initial_commit

21 files changed, 9050 insertions, 0 deletions

diff --git a/fs/ext2/Kconfig b/fs/ext2/Kconfig
new file mode 100644
index 00000000..14a6780f
--- /dev/null
+++ b/fs/ext2/Kconfig
@@ -0,0 +1,55 @@
+config EXT2_FS
+	tristate "Second extended fs support"
+	help
+	  Ext2 is a standard Linux file system for hard disks.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called ext2.
+
+	  If unsure, say Y.
+
+config EXT2_FS_XATTR
+	bool "Ext2 extended attributes"
+	depends on EXT2_FS
+	help
+	  Extended attributes are name:value pairs associated with inodes by
+	  the kernel or by users (see the attr(5) manual page, or visit
+	  <http://acl.bestbits.at/> for details).
+
+	  If unsure, say N.
+
+config EXT2_FS_POSIX_ACL
+	bool "Ext2 POSIX Access Control Lists"
+	depends on EXT2_FS_XATTR
+	select FS_POSIX_ACL
+	help
+	  Posix Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  To learn more about Access Control Lists, visit the Posix ACLs for
+	  Linux website <http://acl.bestbits.at/>.
+
+	  If you don't know what Access Control Lists are, say N
+
+config EXT2_FS_SECURITY
+	bool "Ext2 Security Labels"
+	depends on EXT2_FS_XATTR
+	help
+	  Security labels support alternative access control models
+	  implemented by security modules like SELinux.  This option
+	  enables an extended attribute handler for file security
+	  labels in the ext2 filesystem.
+
+	  If you are not using a security module that requires using
+	  extended attributes for file security labels, say N.
+
+config EXT2_FS_XIP
+	bool "Ext2 execute in place support"
+	depends on EXT2_FS && MMU
+	help
+	  Execute in place can be used on memory-backed block devices. If you
+	  enable this option, you can select to mount block devices which are
+	  capable of this feature without using the page cache.
+
+	  If you do not use a block device that is capable of using this,
+	  or if unsure, say N.
diff --git a/fs/ext2/Makefile b/fs/ext2/Makefile
new file mode 100644
index 00000000..f42af45c
--- /dev/null
+++ b/fs/ext2/Makefile
@@ -0,0 +1,13 @@
+#
+# Makefile for the linux ext2-filesystem routines.
+#
+
+obj-$(CONFIG_EXT2_FS) += ext2.o
+
+ext2-y := balloc.o dir.o file.o ialloc.o inode.o \
+	  ioctl.o namei.o super.o symlink.o
+
+ext2-$(CONFIG_EXT2_FS_XATTR)	 += xattr.o xattr_user.o xattr_trusted.o
+ext2-$(CONFIG_EXT2_FS_POSIX_ACL) += acl.o
+ext2-$(CONFIG_EXT2_FS_SECURITY)	 += xattr_security.o
+ext2-$(CONFIG_EXT2_FS_XIP)	 += xip.o
diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
new file mode 100644
index 00000000..abea5a17
--- /dev/null
+++ b/fs/ext2/acl.c
@@ -0,0 +1,445 @@
+/*
+ * linux/fs/ext2/acl.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ */
+
+#include <linux/capability.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Convert from filesystem to in-memory representation.
+ */
+static struct posix_acl *
+ext2_acl_from_disk(const void *value, size_t size)
+{
+	const char *end = (char *)value + size;
+	int n, count;
+	struct posix_acl *acl;
+
+	if (!value)
+		return NULL;
+	if (size < sizeof(ext2_acl_header))
+		 return ERR_PTR(-EINVAL);
+	if (((ext2_acl_header *)value)->a_version !=
+	    cpu_to_le32(EXT2_ACL_VERSION))
+		return ERR_PTR(-EINVAL);
+	value = (char *)value + sizeof(ext2_acl_header);
+	count = ext2_acl_count(size);
+	if (count < 0)
+		return ERR_PTR(-EINVAL);
+	if (count == 0)
+		return NULL;
+	acl = posix_acl_alloc(count, GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+	for (n=0; n < count; n++) {
+		ext2_acl_entry *entry =
+			(ext2_acl_entry *)value;
+		if ((char *)value + sizeof(ext2_acl_entry_short) > end)
+			goto fail;
+		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
+		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
+		switch(acl->a_entries[n].e_tag) {
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				value = (char *)value +
+					sizeof(ext2_acl_entry_short);
+				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
+				break;
+
+			case ACL_USER:
+			case ACL_GROUP:
+				value = (char *)value + sizeof(ext2_acl_entry);
+				if ((char *)value > end)
+					goto fail;
+				acl->a_entries[n].e_id =
+					le32_to_cpu(entry->e_id);
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	if (value != end)
+		goto fail;
+	return acl;
+
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * Convert from in-memory to filesystem representation.
+ */
+static void *
+ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
+{
+	ext2_acl_header *ext_acl;
+	char *e;
+	size_t n;
+
+	*size = ext2_acl_size(acl->a_count);
+	ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
+			sizeof(ext2_acl_entry), GFP_KERNEL);
+	if (!ext_acl)
+		return ERR_PTR(-ENOMEM);
+	ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
+	e = (char *)ext_acl + sizeof(ext2_acl_header);
+	for (n=0; n < acl->a_count; n++) {
+		ext2_acl_entry *entry = (ext2_acl_entry *)e;
+		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
+		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
+		switch(acl->a_entries[n].e_tag) {
+			case ACL_USER:
+			case ACL_GROUP:
+				entry->e_id =
+					cpu_to_le32(acl->a_entries[n].e_id);
+				e += sizeof(ext2_acl_entry);
+				break;
+
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				e += sizeof(ext2_acl_entry_short);
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	return (char *)ext_acl;
+
+fail:
+	kfree(ext_acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * inode->i_mutex: don't care
+ */
+static struct posix_acl *
+ext2_get_acl(struct inode *inode, int type)
+{
+	int name_index;
+	char *value = NULL;
+	struct posix_acl *acl;
+	int retval;
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return NULL;
+
+	acl = get_cached_acl(inode, type);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
+	if (retval > 0) {
+		value = kmalloc(retval, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		retval = ext2_xattr_get(inode, name_index, "", value, retval);
+	}
+	if (retval > 0)
+		acl = ext2_acl_from_disk(value, retval);
+	else if (retval == -ENODATA || retval == -ENOSYS)
+		acl = NULL;
+	else
+		acl = ERR_PTR(retval);
+	kfree(value);
+
+	if (!IS_ERR(acl))
+		set_cached_acl(inode, type, acl);
+
+	return acl;
+}
+
+/*
+ * inode->i_mutex: down
+ */
+static int
+ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+	int name_index;
+	void *value = NULL;
+	size_t size = 0;
+	int error;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return 0;
+
+	switch(type) {
+		case ACL_TYPE_ACCESS:
+			name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
+			if (acl) {
+				mode_t mode = inode->i_mode;
+				error = posix_acl_equiv_mode(acl, &mode);
+				if (error < 0)
+					return error;
+				else {
+					inode->i_mode = mode;
+					inode->i_ctime = CURRENT_TIME_SEC;
+					mark_inode_dirty(inode);
+					if (error == 0)
+						acl = NULL;
+				}
+			}
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
+			if (!S_ISDIR(inode->i_mode))
+				return acl ? -EACCES : 0;
+			break;
+
+		default:
+			return -EINVAL;
+	}
+ 	if (acl) {
+		value = ext2_acl_to_disk(acl, &size);
+		if (IS_ERR(value))
+			return (int)PTR_ERR(value);
+	}
+
+	error = ext2_xattr_set(inode, name_index, "", value, size, 0);
+
+	kfree(value);
+	if (!error)
+		set_cached_acl(inode, type, acl);
+	return error;
+}
+
+int
+ext2_check_acl(struct inode *inode, int mask, unsigned int flags)
+{
+	struct posix_acl *acl;
+
+	if (flags & IPERM_FLAG_RCU) {
+		if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+			return -ECHILD;
+		return -EAGAIN;
+	}
+
+	acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl) {
+		int error = posix_acl_permission(inode, acl, mask);
+		posix_acl_release(acl);
+		return error;
+	}
+
+	return -EAGAIN;
+}
+
+/*
+ * Initialize the ACLs of a new inode. Called from ext2_new_inode.
+ *
+ * dir->i_mutex: down
+ * inode->i_mutex: up (access to inode is still exclusive)
+ */
+int
+ext2_init_acl(struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *acl = NULL;
+	int error = 0;
+
+	if (!S_ISLNK(inode->i_mode)) {
+		if (test_opt(dir->i_sb, POSIX_ACL)) {
+			acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
+			if (IS_ERR(acl))
+				return PTR_ERR(acl);
+		}
+		if (!acl)
+			inode->i_mode &= ~current_umask();
+	}
+	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
+               struct posix_acl *clone;
+	       mode_t mode;
+
+		if (S_ISDIR(inode->i_mode)) {
+			error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
+			if (error)
+				goto cleanup;
+		}
+		clone = posix_acl_clone(acl, GFP_KERNEL);
+		error = -ENOMEM;
+		if (!clone)
+			goto cleanup;
+		mode = inode->i_mode;
+		error = posix_acl_create_masq(clone, &mode);
+		if (error >= 0) {
+			inode->i_mode = mode;
+			if (error > 0) {
+				/* This is an extended ACL */
+				error = ext2_set_acl(inode,
+						     ACL_TYPE_ACCESS, clone);
+			}
+		}
+		posix_acl_release(clone);
+	}
+cleanup:
+       posix_acl_release(acl);
+       return error;
+}
+
+/*
+ * Does chmod for an inode that may have an Access Control List. The
+ * inode->i_mode field must be updated to the desired value by the caller
+ * before calling this function.
+ * Returns 0 on success, or a negative error number.
+ *
+ * We change the ACL rather than storing some ACL entries in the file
+ * mode permission bits (which would be more efficient), because that
+ * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
+ * for directories) are added. There are no more bits available in the
+ * file mode.
+ *
+ * inode->i_mutex: down
+ */
+int
+ext2_acl_chmod(struct inode *inode)
+{
+	struct posix_acl *acl, *clone;
+        int error;
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return 0;
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl) || !acl)
+		return PTR_ERR(acl);
+	clone = posix_acl_clone(acl, GFP_KERNEL);
+	posix_acl_release(acl);
+	if (!clone)
+		return -ENOMEM;
+	error = posix_acl_chmod_masq(clone, inode->i_mode);
+	if (!error)
+		error = ext2_set_acl(inode, ACL_TYPE_ACCESS, clone);
+	posix_acl_release(clone);
+	return error;
+}
+
+/*
+ * Extended attribut handlers
+ */
+static size_t
+ext2_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_size,
+			   const char *name, size_t name_len, int type)
+{
+	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
+
+	if (!test_opt(dentry->d_sb, POSIX_ACL))
+		return 0;
+	if (list && size <= list_size)
+		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
+	return size;
+}
+
+static size_t
+ext2_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_size,
+			    const char *name, size_t name_len, int type)
+{
+	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
+
+	if (!test_opt(dentry->d_sb, POSIX_ACL))
+		return 0;
+	if (list && size <= list_size)
+		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
+	return size;
+}
+
+static int
+ext2_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
+		   size_t size, int type)
+{
+	struct posix_acl *acl;
+	int error;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	if (!test_opt(dentry->d_sb, POSIX_ACL))
+		return -EOPNOTSUPP;
+
+	acl = ext2_get_acl(dentry->d_inode, type);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl == NULL)
+		return -ENODATA;
+	error = posix_acl_to_xattr(acl, buffer, size);
+	posix_acl_release(acl);
+
+	return error;
+}
+
+static int
+ext2_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
+		   size_t size, int flags, int type)
+{
+	struct posix_acl *acl;
+	int error;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	if (!test_opt(dentry->d_sb, POSIX_ACL))
+		return -EOPNOTSUPP;
+	if (!inode_owner_or_capable(dentry->d_inode))
+		return -EPERM;
+
+	if (value) {
+		acl = posix_acl_from_xattr(value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		else if (acl) {
+			error = posix_acl_valid(acl);
+			if (error)
+				goto release_and_out;
+		}
+	} else
+		acl = NULL;
+
+	error = ext2_set_acl(dentry->d_inode, type, acl);
+
+release_and_out:
+	posix_acl_release(acl);
+	return error;
+}
+
+const struct xattr_handler ext2_xattr_acl_access_handler = {
+	.prefix	= POSIX_ACL_XATTR_ACCESS,
+	.flags	= ACL_TYPE_ACCESS,
+	.list	= ext2_xattr_list_acl_access,
+	.get	= ext2_xattr_get_acl,
+	.set	= ext2_xattr_set_acl,
+};
+
+const struct xattr_handler ext2_xattr_acl_default_handler = {
+	.prefix	= POSIX_ACL_XATTR_DEFAULT,
+	.flags	= ACL_TYPE_DEFAULT,
+	.list	= ext2_xattr_list_acl_default,
+	.get	= ext2_xattr_get_acl,
+	.set	= ext2_xattr_set_acl,
+};
diff --git a/fs/ext2/acl.h b/fs/ext2/acl.h
new file mode 100644
index 00000000..c939b7b1
--- /dev/null
+++ b/fs/ext2/acl.h
@@ -0,0 +1,78 @@
+/*
+  File: fs/ext2/acl.h
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/posix_acl_xattr.h>
+
+#define EXT2_ACL_VERSION	0x0001
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+	__le32		e_id;
+} ext2_acl_entry;
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+} ext2_acl_entry_short;
+
+typedef struct {
+	__le32		a_version;
+} ext2_acl_header;
+
+static inline size_t ext2_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(ext2_acl_header) +
+		       count * sizeof(ext2_acl_entry_short);
+	} else {
+		return sizeof(ext2_acl_header) +
+		       4 * sizeof(ext2_acl_entry_short) +
+		       (count - 4) * sizeof(ext2_acl_entry);
+	}
+}
+
+static inline int ext2_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext2_acl_header);
+	s = size - 4 * sizeof(ext2_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext2_acl_entry_short))
+			return -1;
+		return size / sizeof(ext2_acl_entry_short);
+	} else {
+		if (s % sizeof(ext2_acl_entry))
+			return -1;
+		return s / sizeof(ext2_acl_entry) + 4;
+	}
+}
+
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+
+/* acl.c */
+extern int ext2_check_acl (struct inode *, int, unsigned int);
+extern int ext2_acl_chmod (struct inode *);
+extern int ext2_init_acl (struct inode *, struct inode *);
+
+#else
+#include <linux/sched.h>
+#define ext2_check_acl	NULL
+#define ext2_get_acl	NULL
+#define ext2_set_acl	NULL
+
+static inline int
+ext2_acl_chmod (struct inode *inode)
+{
+	return 0;
+}
+
+static inline int ext2_init_acl (struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+#endif
+
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
new file mode 100644
index 00000000..8f44cef1
--- /dev/null
+++ b/fs/ext2/balloc.c
@@ -0,0 +1,1555 @@
+/*
+ *  linux/fs/ext2/balloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include "ext2.h"
+#include <linux/quotaops.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/buffer_head.h>
+#include <linux/capability.h>
+
+/*
+ * balloc.c contains the blocks allocation and deallocation routines
+ */
+
+/*
+ * The free blocks are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.  The descriptors are loaded in memory
+ * when a file system is mounted (see ext2_fill_super).
+ */
+
+
+#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
+
+struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
+					     unsigned int block_group,
+					     struct buffer_head ** bh)
+{
+	unsigned long group_desc;
+	unsigned long offset;
+	struct ext2_group_desc * desc;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	if (block_group >= sbi->s_groups_count) {
+		ext2_error (sb, "ext2_get_group_desc",
+			    "block_group >= groups_count - "
+			    "block_group = %d, groups_count = %lu",
+			    block_group, sbi->s_groups_count);
+
+		return NULL;
+	}
+
+	group_desc = block_group >> EXT2_DESC_PER_BLOCK_BITS(sb);
+	offset = block_group & (EXT2_DESC_PER_BLOCK(sb) - 1);
+	if (!sbi->s_group_desc[group_desc]) {
+		ext2_error (sb, "ext2_get_group_desc",
+			    "Group descriptor not loaded - "
+			    "block_group = %d, group_desc = %lu, desc = %lu",
+			     block_group, group_desc, offset);
+		return NULL;
+	}
+
+	desc = (struct ext2_group_desc *) sbi->s_group_desc[group_desc]->b_data;
+	if (bh)
+		*bh = sbi->s_group_desc[group_desc];
+	return desc + offset;
+}
+
+static int ext2_valid_block_bitmap(struct super_block *sb,
+					struct ext2_group_desc *desc,
+					unsigned int block_group,
+					struct buffer_head *bh)
+{
+	ext2_grpblk_t offset;
+	ext2_grpblk_t next_zero_bit;
+	ext2_fsblk_t bitmap_blk;
+	ext2_fsblk_t group_first_block;
+
+	group_first_block = ext2_group_first_block_no(sb, block_group);
+
+	/* check whether block bitmap block number is set */
+	bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+	offset = bitmap_blk - group_first_block;
+	if (!ext2_test_bit(offset, bh->b_data))
+		/* bad block bitmap */
+		goto err_out;
+
+	/* check whether the inode bitmap block number is set */
+	bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
+	offset = bitmap_blk - group_first_block;
+	if (!ext2_test_bit(offset, bh->b_data))
+		/* bad block bitmap */
+		goto err_out;
+
+	/* check whether the inode table block number is set */
+	bitmap_blk = le32_to_cpu(desc->bg_inode_table);
+	offset = bitmap_blk - group_first_block;
+	next_zero_bit = ext2_find_next_zero_bit(bh->b_data,
+				offset + EXT2_SB(sb)->s_itb_per_group,
+				offset);
+	if (next_zero_bit >= offset + EXT2_SB(sb)->s_itb_per_group)
+		/* good bitmap for inode tables */
+		return 1;
+
+err_out:
+	ext2_error(sb, __func__,
+			"Invalid block bitmap - "
+			"block_group = %d, block = %lu",
+			block_group, bitmap_blk);
+	return 0;
+}
+
+/*
+ * Read the bitmap for a given block_group,and validate the
+ * bits for block/inode/inode tables are set in the bitmaps
+ *
+ * Return buffer_head on success or NULL in case of failure.
+ */
+static struct buffer_head *
+read_block_bitmap(struct super_block *sb, unsigned int block_group)
+{
+	struct ext2_group_desc * desc;
+	struct buffer_head * bh = NULL;
+	ext2_fsblk_t bitmap_blk;
+
+	desc = ext2_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		return NULL;
+	bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
+	bh = sb_getblk(sb, bitmap_blk);
+	if (unlikely(!bh)) {
+		ext2_error(sb, __func__,
+			    "Cannot read block bitmap - "
+			    "block_group = %d, block_bitmap = %u",
+			    block_group, le32_to_cpu(desc->bg_block_bitmap));
+		return NULL;
+	}
+	if (likely(bh_uptodate_or_lock(bh)))
+		return bh;
+
+	if (bh_submit_read(bh) < 0) {
+		brelse(bh);
+		ext2_error(sb, __func__,
+			    "Cannot read block bitmap - "
+			    "block_group = %d, block_bitmap = %u",
+			    block_group, le32_to_cpu(desc->bg_block_bitmap));
+		return NULL;
+	}
+
+	ext2_valid_block_bitmap(sb, desc, block_group, bh);
+	/*
+	 * file system mounted not to panic on error, continue with corrupt
+	 * bitmap
+	 */
+	return bh;
+}
+
+static void release_blocks(struct super_block *sb, int count)
+{
+	if (count) {
+		struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+		percpu_counter_add(&sbi->s_freeblocks_counter, count);
+		sb->s_dirt = 1;
+	}
+}
+
+static void group_adjust_blocks(struct super_block *sb, int group_no,
+	struct ext2_group_desc *desc, struct buffer_head *bh, int count)
+{
+	if (count) {
+		struct ext2_sb_info *sbi = EXT2_SB(sb);
+		unsigned free_blocks;
+
+		spin_lock(sb_bgl_lock(sbi, group_no));
+		free_blocks = le16_to_cpu(desc->bg_free_blocks_count);
+		desc->bg_free_blocks_count = cpu_to_le16(free_blocks + count);
+		spin_unlock(sb_bgl_lock(sbi, group_no));
+		sb->s_dirt = 1;
+		mark_buffer_dirty(bh);
+	}
+}
+
+/*
+ * The reservation window structure operations
+ * --------------------------------------------
+ * Operations include:
+ * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
+ *
+ * We use a red-black tree to represent per-filesystem reservation
+ * windows.
+ *
+ */
+
+/**
+ * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
+ * @rb_root:		root of per-filesystem reservation rb tree
+ * @verbose:		verbose mode
+ * @fn:			function which wishes to dump the reservation map
+ *
+ * If verbose is turned on, it will print the whole block reservation
+ * windows(start, end). Otherwise, it will only print out the "bad" windows,
+ * those windows that overlap with their immediate neighbors.
+ */
+#if 1
+static void __rsv_window_dump(struct rb_root *root, int verbose,
+			      const char *fn)
+{
+	struct rb_node *n;
+	struct ext2_reserve_window_node *rsv, *prev;
+	int bad;
+
+restart:
+	n = rb_first(root);
+	bad = 0;
+	prev = NULL;
+
+	printk("Block Allocation Reservation Windows Map (%s):\n", fn);
+	while (n) {
+		rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
+		if (verbose)
+			printk("reservation window 0x%p "
+				"start: %lu, end: %lu\n",
+				rsv, rsv->rsv_start, rsv->rsv_end);
+		if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
+			printk("Bad reservation %p (start >= end)\n",
+			       rsv);
+			bad = 1;
+		}
+		if (prev && prev->rsv_end >= rsv->rsv_start) {
+			printk("Bad reservation %p (prev->end >= start)\n",
+			       rsv);
+			bad = 1;
+		}
+		if (bad) {
+			if (!verbose) {
+				printk("Restarting reservation walk in verbose mode\n");
+				verbose = 1;
+				goto restart;
+			}
+		}
+		n = rb_next(n);
+		prev = rsv;
+	}
+	printk("Window map complete.\n");
+	BUG_ON(bad);
+}
+#define rsv_window_dump(root, verbose) \
+	__rsv_window_dump((root), (verbose), __func__)
+#else
+#define rsv_window_dump(root, verbose) do {} while (0)
+#endif
+
+/**
+ * goal_in_my_reservation()
+ * @rsv:		inode's reservation window
+ * @grp_goal:		given goal block relative to the allocation block group
+ * @group:		the current allocation block group
+ * @sb:			filesystem super block
+ *
+ * Test if the given goal block (group relative) is within the file's
+ * own block reservation window range.
+ *
+ * If the reservation window is outside the goal allocation group, return 0;
+ * grp_goal (given goal block) could be -1, which means no specific
+ * goal block. In this case, always return 1.
+ * If the goal block is within the reservation window, return 1;
+ * otherwise, return 0;
+ */
+static int
+goal_in_my_reservation(struct ext2_reserve_window *rsv, ext2_grpblk_t grp_goal,
+			unsigned int group, struct super_block * sb)
+{
+	ext2_fsblk_t group_first_block, group_last_block;
+
+	group_first_block = ext2_group_first_block_no(sb, group);
+	group_last_block = group_first_block + EXT2_BLOCKS_PER_GROUP(sb) - 1;
+
+	if ((rsv->_rsv_start > group_last_block) ||
+	    (rsv->_rsv_end < group_first_block))
+		return 0;
+	if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
+		|| (grp_goal + group_first_block > rsv->_rsv_end)))
+		return 0;
+	return 1;
+}
+
+/**
+ * search_reserve_window()
+ * @rb_root:		root of reservation tree
+ * @goal:		target allocation block
+ *
+ * Find the reserved window which includes the goal, or the previous one
+ * if the goal is not in any window.
+ * Returns NULL if there are no windows or if all windows start after the goal.
+ */
+static struct ext2_reserve_window_node *
+search_reserve_window(struct rb_root *root, ext2_fsblk_t goal)
+{
+	struct rb_node *n = root->rb_node;
+	struct ext2_reserve_window_node *rsv;
+
+	if (!n)
+		return NULL;
+
+	do {
+		rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
+
+		if (goal < rsv->rsv_start)
+			n = n->rb_left;
+		else if (goal > rsv->rsv_end)
+			n = n->rb_right;
+		else
+			return rsv;
+	} while (n);
+	/*
+	 * We've fallen off the end of the tree: the goal wasn't inside
+	 * any particular node.  OK, the previous node must be to one
+	 * side of the interval containing the goal.  If it's the RHS,
+	 * we need to back up one.
+	 */
+	if (rsv->rsv_start > goal) {
+		n = rb_prev(&rsv->rsv_node);
+		rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
+	}
+	return rsv;
+}
+
+/*
+ * ext2_rsv_window_add() -- Insert a window to the block reservation rb tree.
+ * @sb:			super block
+ * @rsv:		reservation window to add
+ *
+ * Must be called with rsv_lock held.
+ */
+void ext2_rsv_window_add(struct super_block *sb,
+		    struct ext2_reserve_window_node *rsv)
+{
+	struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root;
+	struct rb_node *node = &rsv->rsv_node;
+	ext2_fsblk_t start = rsv->rsv_start;
+
+	struct rb_node ** p = &root->rb_node;
+	struct rb_node * parent = NULL;
+	struct ext2_reserve_window_node *this;
+
+	while (*p)
+	{
+		parent = *p;
+		this = rb_entry(parent, struct ext2_reserve_window_node, rsv_node);
+
+		if (start < this->rsv_start)
+			p = &(*p)->rb_left;
+		else if (start > this->rsv_end)
+			p = &(*p)->rb_right;
+		else {
+			rsv_window_dump(root, 1);
+			BUG();
+		}
+	}
+
+	rb_link_node(node, parent, p);
+	rb_insert_color(node, root);
+}
+
+/**
+ * rsv_window_remove() -- unlink a window from the reservation rb tree
+ * @sb:			super block
+ * @rsv:		reservation window to remove
+ *
+ * Mark the block reservation window as not allocated, and unlink it
+ * from the filesystem reservation window rb tree. Must be called with
+ * rsv_lock held.
+ */
+static void rsv_window_remove(struct super_block *sb,
+			      struct ext2_reserve_window_node *rsv)
+{
+	rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+	rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+	rsv->rsv_alloc_hit = 0;
+	rb_erase(&rsv->rsv_node, &EXT2_SB(sb)->s_rsv_window_root);
+}
+
+/*
+ * rsv_is_empty() -- Check if the reservation window is allocated.
+ * @rsv:		given reservation window to check
+ *
+ * returns 1 if the end block is EXT2_RESERVE_WINDOW_NOT_ALLOCATED.
+ */
+static inline int rsv_is_empty(struct ext2_reserve_window *rsv)
+{
+	/* a valid reservation end block could not be 0 */
+	return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED);
+}
+
+/**
+ * ext2_init_block_alloc_info()
+ * @inode:		file inode structure
+ *
+ * Allocate and initialize the  reservation window structure, and
+ * link the window to the ext2 inode structure at last
+ *
+ * The reservation window structure is only dynamically allocated
+ * and linked to ext2 inode the first time the open file
+ * needs a new block. So, before every ext2_new_block(s) call, for
+ * regular files, we should check whether the reservation window
+ * structure exists or not. In the latter case, this function is called.
+ * Fail to do so will result in block reservation being turned off for that
+ * open file.
+ *
+ * This function is called from ext2_get_blocks_handle(), also called
+ * when setting the reservation window size through ioctl before the file
+ * is open for write (needs block allocation).
+ *
+ * Needs truncate_mutex protection prior to calling this function.
+ */
+void ext2_init_block_alloc_info(struct inode *inode)
+{
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info;
+	struct super_block *sb = inode->i_sb;
+
+	block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
+	if (block_i) {
+		struct ext2_reserve_window_node *rsv = &block_i->rsv_window_node;
+
+		rsv->rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+		rsv->rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+
+	 	/*
+		 * if filesystem is mounted with NORESERVATION, the goal
+		 * reservation window size is set to zero to indicate
+		 * block reservation is off
+		 */
+		if (!test_opt(sb, RESERVATION))
+			rsv->rsv_goal_size = 0;
+		else
+			rsv->rsv_goal_size = EXT2_DEFAULT_RESERVE_BLOCKS;
+		rsv->rsv_alloc_hit = 0;
+		block_i->last_alloc_logical_block = 0;
+		block_i->last_alloc_physical_block = 0;
+	}
+	ei->i_block_alloc_info = block_i;
+}
+
+/**
+ * ext2_discard_reservation()
+ * @inode:		inode
+ *
+ * Discard(free) block reservation window on last file close, or truncate
+ * or at last iput().
+ *
+ * It is being called in three cases:
+ * 	ext2_release_file(): last writer closes the file
+ * 	ext2_clear_inode(): last iput(), when nobody links to this file.
+ * 	ext2_truncate(): when the block indirect map is about to change.
+ */
+void ext2_discard_reservation(struct inode *inode)
+{
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	struct ext2_block_alloc_info *block_i = ei->i_block_alloc_info;
+	struct ext2_reserve_window_node *rsv;
+	spinlock_t *rsv_lock = &EXT2_SB(inode->i_sb)->s_rsv_window_lock;
+
+	if (!block_i)
+		return;
+
+	rsv = &block_i->rsv_window_node;
+	if (!rsv_is_empty(&rsv->rsv_window)) {
+		spin_lock(rsv_lock);
+		if (!rsv_is_empty(&rsv->rsv_window))
+			rsv_window_remove(inode->i_sb, rsv);
+		spin_unlock(rsv_lock);
+	}
+}
+
+/**
+ * ext2_free_blocks_sb() -- Free given blocks and update quota and i_blocks
+ * @inode:		inode
+ * @block:		start physcial block to free
+ * @count:		number of blocks to free
+ */
+void ext2_free_blocks (struct inode * inode, unsigned long block,
+		       unsigned long count)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head * bh2;
+	unsigned long block_group;
+	unsigned long bit;
+	unsigned long i;
+	unsigned long overflow;
+	struct super_block * sb = inode->i_sb;
+	struct ext2_sb_info * sbi = EXT2_SB(sb);
+	struct ext2_group_desc * desc;
+	struct ext2_super_block * es = sbi->s_es;
+	unsigned freed = 0, group_freed;
+
+	if (block < le32_to_cpu(es->s_first_data_block) ||
+	    block + count < block ||
+	    block + count > le32_to_cpu(es->s_blocks_count)) {
+		ext2_error (sb, "ext2_free_blocks",
+			    "Freeing blocks not in datazone - "
+			    "block = %lu, count = %lu", block, count);
+		goto error_return;
+	}
+
+	ext2_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
+
+do_more:
+	overflow = 0;
+	block_group = (block - le32_to_cpu(es->s_first_data_block)) /
+		      EXT2_BLOCKS_PER_GROUP(sb);
+	bit = (block - le32_to_cpu(es->s_first_data_block)) %
+		      EXT2_BLOCKS_PER_GROUP(sb);
+	/*
+	 * Check to see if we are freeing blocks across a group
+	 * boundary.
+	 */
+	if (bit + count > EXT2_BLOCKS_PER_GROUP(sb)) {
+		overflow = bit + count - EXT2_BLOCKS_PER_GROUP(sb);
+		count -= overflow;
+	}
+	brelse(bitmap_bh);
+	bitmap_bh = read_block_bitmap(sb, block_group);
+	if (!bitmap_bh)
+		goto error_return;
+
+	desc = ext2_get_group_desc (sb, block_group, &bh2);
+	if (!desc)
+		goto error_return;
+
+	if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
+	    in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
+	    in_range (block, le32_to_cpu(desc->bg_inode_table),
+		      sbi->s_itb_per_group) ||
+	    in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
+		      sbi->s_itb_per_group)) {
+		ext2_error (sb, "ext2_free_blocks",
+			    "Freeing blocks in system zones - "
+			    "Block = %lu, count = %lu",
+			    block, count);
+		goto error_return;
+	}
+
+	for (i = 0, group_freed = 0; i < count; i++) {
+		if (!ext2_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
+						bit + i, bitmap_bh->b_data)) {
+			ext2_error(sb, __func__,
+				"bit already cleared for block %lu", block + i);
+		} else {
+			group_freed++;
+		}
+	}
+
+	mark_buffer_dirty(bitmap_bh);
+	if (sb->s_flags & MS_SYNCHRONOUS)
+		sync_dirty_buffer(bitmap_bh);
+
+	group_adjust_blocks(sb, block_group, desc, bh2, group_freed);
+	freed += group_freed;
+
+	if (overflow) {
+		block += count;
+		count = overflow;
+		goto do_more;
+	}
+error_return:
+	brelse(bitmap_bh);
+	release_blocks(sb, freed);
+	dquot_free_block_nodirty(inode, freed);
+}
+
+/**
+ * bitmap_search_next_usable_block()
+ * @start:		the starting block (group relative) of the search
+ * @bh:			bufferhead contains the block group bitmap
+ * @maxblocks:		the ending block (group relative) of the reservation
+ *
+ * The bitmap search --- search forward through the actual bitmap on disk until
+ * we find a bit free.
+ */
+static ext2_grpblk_t
+bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh,
+					ext2_grpblk_t maxblocks)
+{
+	ext2_grpblk_t next;
+
+	next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start);
+	if (next >= maxblocks)
+		return -1;
+	return next;
+}
+
+/**
+ * find_next_usable_block()
+ * @start:		the starting block (group relative) to find next
+ * 			allocatable block in bitmap.
+ * @bh:			bufferhead contains the block group bitmap
+ * @maxblocks:		the ending block (group relative) for the search
+ *
+ * Find an allocatable block in a bitmap.  We perform the "most
+ * appropriate allocation" algorithm of looking for a free block near
+ * the initial goal; then for a free byte somewhere in the bitmap;
+ * then for any free bit in the bitmap.
+ */
+static ext2_grpblk_t
+find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
+{
+	ext2_grpblk_t here, next;
+	char *p, *r;
+
+	if (start > 0) {
+		/*
+		 * The goal was occupied; search forward for a free 
+		 * block within the next XX blocks.
+		 *
+		 * end_goal is more or less random, but it has to be
+		 * less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
+		 * next 64-bit boundary is simple..
+		 */
+		ext2_grpblk_t end_goal = (start + 63) & ~63;
+		if (end_goal > maxblocks)
+			end_goal = maxblocks;
+		here = ext2_find_next_zero_bit(bh->b_data, end_goal, start);
+		if (here < end_goal)
+			return here;
+		ext2_debug("Bit not found near goal\n");
+	}
+
+	here = start;
+	if (here < 0)
+		here = 0;
+
+	p = ((char *)bh->b_data) + (here >> 3);
+	r = memscan(p, 0, ((maxblocks + 7) >> 3) - (here >> 3));
+	next = (r - ((char *)bh->b_data)) << 3;
+
+	if (next < maxblocks && next >= here)
+		return next;
+
+	here = bitmap_search_next_usable_block(here, bh, maxblocks);
+	return here;
+}
+
+/**
+ * ext2_try_to_allocate()
+ * @sb:			superblock
+ * @group:		given allocation block group
+ * @bitmap_bh:		bufferhead holds the block bitmap
+ * @grp_goal:		given target block within the group
+ * @count:		target number of blocks to allocate
+ * @my_rsv:		reservation window
+ *
+ * Attempt to allocate blocks within a give range. Set the range of allocation
+ * first, then find the first free bit(s) from the bitmap (within the range),
+ * and at last, allocate the blocks by claiming the found free bit as allocated.
+ *
+ * To set the range of this allocation:
+ * 	if there is a reservation window, only try to allocate block(s)
+ * 	from the file's own reservation window;
+ * 	Otherwise, the allocation range starts from the give goal block,
+ * 	ends at the block group's last block.
+ *
+ * If we failed to allocate the desired block then we may end up crossing to a
+ * new bitmap.
+ */
+static int
+ext2_try_to_allocate(struct super_block *sb, int group,
+			struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
+			unsigned long *count,
+			struct ext2_reserve_window *my_rsv)
+{
+	ext2_fsblk_t group_first_block;
+       	ext2_grpblk_t start, end;
+	unsigned long num = 0;
+
+	/* we do allocation within the reservation window if we have a window */
+	if (my_rsv) {
+		group_first_block = ext2_group_first_block_no(sb, group);
+		if (my_rsv->_rsv_start >= group_first_block)
+			start = my_rsv->_rsv_start - group_first_block;
+		else
+			/* reservation window cross group boundary */
+			start = 0;
+		end = my_rsv->_rsv_end - group_first_block + 1;
+		if (end > EXT2_BLOCKS_PER_GROUP(sb))
+			/* reservation window crosses group boundary */
+			end = EXT2_BLOCKS_PER_GROUP(sb);
+		if ((start <= grp_goal) && (grp_goal < end))
+			start = grp_goal;
+		else
+			grp_goal = -1;
+	} else {
+		if (grp_goal > 0)
+			start = grp_goal;
+		else
+			start = 0;
+		end = EXT2_BLOCKS_PER_GROUP(sb);
+	}
+
+	BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb));
+
+repeat:
+	if (grp_goal < 0) {
+		grp_goal = find_next_usable_block(start, bitmap_bh, end);
+		if (grp_goal < 0)
+			goto fail_access;
+		if (!my_rsv) {
+			int i;
+
+			for (i = 0; i < 7 && grp_goal > start &&
+					!ext2_test_bit(grp_goal - 1,
+					     		bitmap_bh->b_data);
+			     		i++, grp_goal--)
+				;
+		}
+	}
+	start = grp_goal;
+
+	if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), grp_goal,
+			       				bitmap_bh->b_data)) {
+		/*
+		 * The block was allocated by another thread, or it was
+		 * allocated and then freed by another thread
+		 */
+		start++;
+		grp_goal++;
+		if (start >= end)
+			goto fail_access;
+		goto repeat;
+	}
+	num++;
+	grp_goal++;
+	while (num < *count && grp_goal < end
+		&& !ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group),
+					grp_goal, bitmap_bh->b_data)) {
+		num++;
+		grp_goal++;
+	}
+	*count = num;
+	return grp_goal - num;
+fail_access:
+	*count = num;
+	return -1;
+}
+
+/**
+ * 	find_next_reservable_window():
+ *		find a reservable space within the given range.
+ *		It does not allocate the reservation window for now:
+ *		alloc_new_reservation() will do the work later.
+ *
+ * 	@search_head: the head of the searching list;
+ *		This is not necessarily the list head of the whole filesystem
+ *
+ *		We have both head and start_block to assist the search
+ *		for the reservable space. The list starts from head,
+ *		but we will shift to the place where start_block is,
+ *		then start from there, when looking for a reservable space.
+ *
+ * 	@size: the target new reservation window size
+ *
+ * 	@group_first_block: the first block we consider to start
+ *			the real search from
+ *
+ * 	@last_block:
+ *		the maximum block number that our goal reservable space
+ *		could start from. This is normally the last block in this
+ *		group. The search will end when we found the start of next
+ *		possible reservable space is out of this boundary.
+ *		This could handle the cross boundary reservation window
+ *		request.
+ *
+ * 	basically we search from the given range, rather than the whole
+ * 	reservation double linked list, (start_block, last_block)
+ * 	to find a free region that is of my size and has not
+ * 	been reserved.
+ *
+ */
+static int find_next_reservable_window(
+				struct ext2_reserve_window_node *search_head,
+				struct ext2_reserve_window_node *my_rsv,
+				struct super_block * sb,
+				ext2_fsblk_t start_block,
+				ext2_fsblk_t last_block)
+{
+	struct rb_node *next;
+	struct ext2_reserve_window_node *rsv, *prev;
+	ext2_fsblk_t cur;
+	int size = my_rsv->rsv_goal_size;
+
+	/* TODO: make the start of the reservation window byte-aligned */
+	/* cur = *start_block & ~7;*/
+	cur = start_block;
+	rsv = search_head;
+	if (!rsv)
+		return -1;
+
+	while (1) {
+		if (cur <= rsv->rsv_end)
+			cur = rsv->rsv_end + 1;
+
+		/* TODO?
+		 * in the case we could not find a reservable space
+		 * that is what is expected, during the re-search, we could
+		 * remember what's the largest reservable space we could have
+		 * and return that one.
+		 *
+		 * For now it will fail if we could not find the reservable
+		 * space with expected-size (or more)...
+		 */
+		if (cur > last_block)
+			return -1;		/* fail */
+
+		prev = rsv;
+		next = rb_next(&rsv->rsv_node);
+		rsv = rb_entry(next,struct ext2_reserve_window_node,rsv_node);
+
+		/*
+		 * Reached the last reservation, we can just append to the
+		 * previous one.
+		 */
+		if (!next)
+			break;
+
+		if (cur + size <= rsv->rsv_start) {
+			/*
+			 * Found a reserveable space big enough.  We could
+			 * have a reservation across the group boundary here
+		 	 */
+			break;
+		}
+	}
+	/*
+	 * we come here either :
+	 * when we reach the end of the whole list,
+	 * and there is empty reservable space after last entry in the list.
+	 * append it to the end of the list.
+	 *
+	 * or we found one reservable space in the middle of the list,
+	 * return the reservation window that we could append to.
+	 * succeed.
+	 */
+
+	if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
+		rsv_window_remove(sb, my_rsv);
+
+	/*
+	 * Let's book the whole available window for now.  We will check the
+	 * disk bitmap later and then, if there are free blocks then we adjust
+	 * the window size if it's larger than requested.
+	 * Otherwise, we will remove this node from the tree next time
+	 * call find_next_reservable_window.
+	 */
+	my_rsv->rsv_start = cur;
+	my_rsv->rsv_end = cur + size - 1;
+	my_rsv->rsv_alloc_hit = 0;
+
+	if (prev != my_rsv)
+		ext2_rsv_window_add(sb, my_rsv);
+
+	return 0;
+}
+
+/**
+ * 	alloc_new_reservation()--allocate a new reservation window
+ *
+ *		To make a new reservation, we search part of the filesystem
+ *		reservation list (the list that inside the group). We try to
+ *		allocate a new reservation window near the allocation goal,
+ *		or the beginning of the group, if there is no goal.
+ *
+ *		We first find a reservable space after the goal, then from
+ *		there, we check the bitmap for the first free block after
+ *		it. If there is no free block until the end of group, then the
+ *		whole group is full, we failed. Otherwise, check if the free
+ *		block is inside the expected reservable space, if so, we
+ *		succeed.
+ *		If the first free block is outside the reservable space, then
+ *		start from the first free block, we search for next available
+ *		space, and go on.
+ *
+ *	on succeed, a new reservation will be found and inserted into the list
+ *	It contains at least one free block, and it does not overlap with other
+ *	reservation windows.
+ *
+ *	failed: we failed to find a reservation window in this group
+ *
+ *	@rsv: the reservation
+ *
+ *	@grp_goal: The goal (group-relative).  It is where the search for a
+ *		free reservable space should start from.
+ *		if we have a goal(goal >0 ), then start from there,
+ *		no goal(goal = -1), we start from the first block
+ *		of the group.
+ *
+ *	@sb: the super block
+ *	@group: the group we are trying to allocate in
+ *	@bitmap_bh: the block group block bitmap
+ *
+ */
+static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv,
+		ext2_grpblk_t grp_goal, struct super_block *sb,
+		unsigned int group, struct buffer_head *bitmap_bh)
+{
+	struct ext2_reserve_window_node *search_head;
+	ext2_fsblk_t group_first_block, group_end_block, start_block;
+	ext2_grpblk_t first_free_block;
+	struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root;
+	unsigned long size;
+	int ret;
+	spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock;
+
+	group_first_block = ext2_group_first_block_no(sb, group);
+	group_end_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1);
+
+	if (grp_goal < 0)
+		start_block = group_first_block;
+	else
+		start_block = grp_goal + group_first_block;
+
+	size = my_rsv->rsv_goal_size;
+
+	if (!rsv_is_empty(&my_rsv->rsv_window)) {
+		/*
+		 * if the old reservation is cross group boundary
+		 * and if the goal is inside the old reservation window,
+		 * we will come here when we just failed to allocate from
+		 * the first part of the window. We still have another part
+		 * that belongs to the next group. In this case, there is no
+		 * point to discard our window and try to allocate a new one
+		 * in this group(which will fail). we should
+		 * keep the reservation window, just simply move on.
+		 *
+		 * Maybe we could shift the start block of the reservation
+		 * window to the first block of next group.
+		 */
+
+		if ((my_rsv->rsv_start <= group_end_block) &&
+				(my_rsv->rsv_end > group_end_block) &&
+				(start_block >= my_rsv->rsv_start))
+			return -1;
+
+		if ((my_rsv->rsv_alloc_hit >
+		     (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
+			/*
+			 * if the previously allocation hit ratio is
+			 * greater than 1/2, then we double the size of
+			 * the reservation window the next time,
+			 * otherwise we keep the same size window
+			 */
+			size = size * 2;
+			if (size > EXT2_MAX_RESERVE_BLOCKS)
+				size = EXT2_MAX_RESERVE_BLOCKS;
+			my_rsv->rsv_goal_size= size;
+		}
+	}
+
+	spin_lock(rsv_lock);
+	/*
+	 * shift the search start to the window near the goal block
+	 */
+	search_head = search_reserve_window(fs_rsv_root, start_block);
+
+	/*
+	 * find_next_reservable_window() simply finds a reservable window
+	 * inside the given range(start_block, group_end_block).
+	 *
+	 * To make sure the reservation window has a free bit inside it, we
+	 * need to check the bitmap after we found a reservable window.
+	 */
+retry:
+	ret = find_next_reservable_window(search_head, my_rsv, sb,
+						start_block, group_end_block);
+
+	if (ret == -1) {
+		if (!rsv_is_empty(&my_rsv->rsv_window))
+			rsv_window_remove(sb, my_rsv);
+		spin_unlock(rsv_lock);
+		return -1;
+	}
+
+	/*
+	 * On success, find_next_reservable_window() returns the
+	 * reservation window where there is a reservable space after it.
+	 * Before we reserve this reservable space, we need
+	 * to make sure there is at least a free block inside this region.
+	 *
+	 * Search the first free bit on the block bitmap.  Search starts from
+	 * the start block of the reservable space we just found.
+	 */
+	spin_unlock(rsv_lock);
+	first_free_block = bitmap_search_next_usable_block(
+			my_rsv->rsv_start - group_first_block,
+			bitmap_bh, group_end_block - group_first_block + 1);
+
+	if (first_free_block < 0) {
+		/*
+		 * no free block left on the bitmap, no point
+		 * to reserve the space. return failed.
+		 */
+		spin_lock(rsv_lock);
+		if (!rsv_is_empty(&my_rsv->rsv_window))
+			rsv_window_remove(sb, my_rsv);
+		spin_unlock(rsv_lock);
+		return -1;		/* failed */
+	}
+
+	start_block = first_free_block + group_first_block;
+	/*
+	 * check if the first free block is within the
+	 * free space we just reserved
+	 */
+	if (start_block >= my_rsv->rsv_start && start_block <= my_rsv->rsv_end)
+		return 0;		/* success */
+	/*
+	 * if the first free bit we found is out of the reservable space
+	 * continue search for next reservable space,
+	 * start from where the free block is,
+	 * we also shift the list head to where we stopped last time
+	 */
+	search_head = my_rsv;
+	spin_lock(rsv_lock);
+	goto retry;
+}
+
+/**
+ * try_to_extend_reservation()
+ * @my_rsv:		given reservation window
+ * @sb:			super block
+ * @size:		the delta to extend
+ *
+ * Attempt to expand the reservation window large enough to have
+ * required number of free blocks
+ *
+ * Since ext2_try_to_allocate() will always allocate blocks within
+ * the reservation window range, if the window size is too small,
+ * multiple blocks allocation has to stop at the end of the reservation
+ * window. To make this more efficient, given the total number of
+ * blocks needed and the current size of the window, we try to
+ * expand the reservation window size if necessary on a best-effort
+ * basis before ext2_new_blocks() tries to allocate blocks.
+ */
+static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv,
+			struct super_block *sb, int size)
+{
+	struct ext2_reserve_window_node *next_rsv;
+	struct rb_node *next;
+	spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock;
+
+	if (!spin_trylock(rsv_lock))
+		return;
+
+	next = rb_next(&my_rsv->rsv_node);
+
+	if (!next)
+		my_rsv->rsv_end += size;
+	else {
+		next_rsv = rb_entry(next, struct ext2_reserve_window_node, rsv_node);
+
+		if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
+			my_rsv->rsv_end += size;
+		else
+			my_rsv->rsv_end = next_rsv->rsv_start - 1;
+	}
+	spin_unlock(rsv_lock);
+}
+
+/**
+ * ext2_try_to_allocate_with_rsv()
+ * @sb:			superblock
+ * @group:		given allocation block group
+ * @bitmap_bh:		bufferhead holds the block bitmap
+ * @grp_goal:		given target block within the group
+ * @count:		target number of blocks to allocate
+ * @my_rsv:		reservation window
+ *
+ * This is the main function used to allocate a new block and its reservation
+ * window.
+ *
+ * Each time when a new block allocation is need, first try to allocate from
+ * its own reservation.  If it does not have a reservation window, instead of
+ * looking for a free bit on bitmap first, then look up the reservation list to
+ * see if it is inside somebody else's reservation window, we try to allocate a
+ * reservation window for it starting from the goal first. Then do the block
+ * allocation within the reservation window.
+ *
+ * This will avoid keeping on searching the reservation list again and
+ * again when somebody is looking for a free block (without
+ * reservation), and there are lots of free blocks, but they are all
+ * being reserved.
+ *
+ * We use a red-black tree for the per-filesystem reservation list.
+ */
+static ext2_grpblk_t
+ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group,
+			struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
+			struct ext2_reserve_window_node * my_rsv,
+			unsigned long *count)
+{
+	ext2_fsblk_t group_first_block, group_last_block;
+	ext2_grpblk_t ret = 0;
+	unsigned long num = *count;
+
+	/*
+	 * we don't deal with reservation when
+	 * filesystem is mounted without reservation
+	 * or the file is not a regular file
+	 * or last attempt to allocate a block with reservation turned on failed
+	 */
+	if (my_rsv == NULL) {
+		return ext2_try_to_allocate(sb, group, bitmap_bh,
+						grp_goal, count, NULL);
+	}
+	/*
+	 * grp_goal is a group relative block number (if there is a goal)
+	 * 0 <= grp_goal < EXT2_BLOCKS_PER_GROUP(sb)
+	 * first block is a filesystem wide block number
+	 * first block is the block number of the first block in this group
+	 */
+	group_first_block = ext2_group_first_block_no(sb, group);
+	group_last_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1);
+
+	/*
+	 * Basically we will allocate a new block from inode's reservation
+	 * window.
+	 *
+	 * We need to allocate a new reservation window, if:
+	 * a) inode does not have a reservation window; or
+	 * b) last attempt to allocate a block from existing reservation
+	 *    failed; or
+	 * c) we come here with a goal and with a reservation window
+	 *
+	 * We do not need to allocate a new reservation window if we come here
+	 * at the beginning with a goal and the goal is inside the window, or
+	 * we don't have a goal but already have a reservation window.
+	 * then we could go to allocate from the reservation window directly.
+	 */
+	while (1) {
+		if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
+			!goal_in_my_reservation(&my_rsv->rsv_window,
+						grp_goal, group, sb)) {
+			if (my_rsv->rsv_goal_size < *count)
+				my_rsv->rsv_goal_size = *count;
+			ret = alloc_new_reservation(my_rsv, grp_goal, sb,
+							group, bitmap_bh);
+			if (ret < 0)
+				break;			/* failed */
+
+			if (!goal_in_my_reservation(&my_rsv->rsv_window,
+							grp_goal, group, sb))
+				grp_goal = -1;
+		} else if (grp_goal >= 0) {
+			int curr = my_rsv->rsv_end -
+					(grp_goal + group_first_block) + 1;
+
+			if (curr < *count)
+				try_to_extend_reservation(my_rsv, sb,
+							*count - curr);
+		}
+
+		if ((my_rsv->rsv_start > group_last_block) ||
+				(my_rsv->rsv_end < group_first_block)) {
+			rsv_window_dump(&EXT2_SB(sb)->s_rsv_window_root, 1);
+			BUG();
+		}
+		ret = ext2_try_to_allocate(sb, group, bitmap_bh, grp_goal,
+					   &num, &my_rsv->rsv_window);
+		if (ret >= 0) {
+			my_rsv->rsv_alloc_hit += num;
+			*count = num;
+			break;				/* succeed */
+		}
+		num = *count;
+	}
+	return ret;
+}
+
+/**
+ * ext2_has_free_blocks()
+ * @sbi:		in-core super block structure.
+ *
+ * Check if filesystem has at least 1 free block available for allocation.
+ */
+static int ext2_has_free_blocks(struct ext2_sb_info *sbi)
+{
+	ext2_fsblk_t free_blocks, root_blocks;
+
+	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+	root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
+	if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
+		sbi->s_resuid != current_fsuid() &&
+		(sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
+		return 0;
+	}
+	return 1;
+}
+
+/*
+ * ext2_new_blocks() -- core block(s) allocation function
+ * @inode:		file inode
+ * @goal:		given target block(filesystem wide)
+ * @count:		target number of blocks to allocate
+ * @errp:		error code
+ *
+ * ext2_new_blocks uses a goal block to assist allocation.  If the goal is
+ * free, or there is a free block within 32 blocks of the goal, that block
+ * is allocated.  Otherwise a forward search is made for a free block; within 
+ * each block group the search first looks for an entire free byte in the block
+ * bitmap, and then for any free bit if that fails.
+ * This function also updates quota and i_blocks field.
+ */
+ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
+		    unsigned long *count, int *errp)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *gdp_bh;
+	int group_no;
+	int goal_group;
+	ext2_grpblk_t grp_target_blk;	/* blockgroup relative goal block */
+	ext2_grpblk_t grp_alloc_blk;	/* blockgroup-relative allocated block*/
+	ext2_fsblk_t ret_block;		/* filesyetem-wide allocated block */
+	int bgi;			/* blockgroup iteration index */
+	int performed_allocation = 0;
+	ext2_grpblk_t free_blocks;	/* number of free blocks in a group */
+	struct super_block *sb;
+	struct ext2_group_desc *gdp;
+	struct ext2_super_block *es;
+	struct ext2_sb_info *sbi;
+	struct ext2_reserve_window_node *my_rsv = NULL;
+	struct ext2_block_alloc_info *block_i;
+	unsigned short windowsz = 0;
+	unsigned long ngroups;
+	unsigned long num = *count;
+	int ret;
+
+	*errp = -ENOSPC;
+	sb = inode->i_sb;
+	if (!sb) {
+		printk("ext2_new_blocks: nonexistent device");
+		return 0;
+	}
+
+	/*
+	 * Check quota for allocation of this block.
+	 */
+	ret = dquot_alloc_block(inode, num);
+	if (ret) {
+		*errp = ret;
+		return 0;
+	}
+
+	sbi = EXT2_SB(sb);
+	es = EXT2_SB(sb)->s_es;
+	ext2_debug("goal=%lu.\n", goal);
+	/*
+	 * Allocate a block from reservation only when
+	 * filesystem is mounted with reservation(default,-o reservation), and
+	 * it's a regular file, and
+	 * the desired window size is greater than 0 (One could use ioctl
+	 * command EXT2_IOC_SETRSVSZ to set the window size to 0 to turn off
+	 * reservation on that particular file)
+	 */
+	block_i = EXT2_I(inode)->i_block_alloc_info;
+	if (block_i) {
+		windowsz = block_i->rsv_window_node.rsv_goal_size;
+		if (windowsz > 0)
+			my_rsv = &block_i->rsv_window_node;
+	}
+
+	if (!ext2_has_free_blocks(sbi)) {
+		*errp = -ENOSPC;
+		goto out;
+	}
+
+	/*
+	 * First, test whether the goal block is free.
+	 */
+	if (goal < le32_to_cpu(es->s_first_data_block) ||
+	    goal >= le32_to_cpu(es->s_blocks_count))
+		goal = le32_to_cpu(es->s_first_data_block);
+	group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
+			EXT2_BLOCKS_PER_GROUP(sb);
+	goal_group = group_no;
+retry_alloc:
+	gdp = ext2_get_group_desc(sb, group_no, &gdp_bh);
+	if (!gdp)
+		goto io_error;
+
+	free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+	/*
+	 * if there is not enough free blocks to make a new resevation
+	 * turn off reservation for this allocation
+	 */
+	if (my_rsv && (free_blocks < windowsz)
+		&& (free_blocks > 0)
+		&& (rsv_is_empty(&my_rsv->rsv_window)))
+		my_rsv = NULL;
+
+	if (free_blocks > 0) {
+		grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
+				EXT2_BLOCKS_PER_GROUP(sb));
+		bitmap_bh = read_block_bitmap(sb, group_no);
+		if (!bitmap_bh)
+			goto io_error;
+		grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
+					bitmap_bh, grp_target_blk,
+					my_rsv, &num);
+		if (grp_alloc_blk >= 0)
+			goto allocated;
+	}
+
+	ngroups = EXT2_SB(sb)->s_groups_count;
+	smp_rmb();
+
+	/*
+	 * Now search the rest of the groups.  We assume that
+	 * group_no and gdp correctly point to the last group visited.
+	 */
+	for (bgi = 0; bgi < ngroups; bgi++) {
+		group_no++;
+		if (group_no >= ngroups)
+			group_no = 0;
+		gdp = ext2_get_group_desc(sb, group_no, &gdp_bh);
+		if (!gdp)
+			goto io_error;
+
+		free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+		/*
+		 * skip this group (and avoid loading bitmap) if there
+		 * are no free blocks
+		 */
+		if (!free_blocks)
+			continue;
+		/*
+		 * skip this group if the number of
+		 * free blocks is less than half of the reservation
+		 * window size.
+		 */
+		if (my_rsv && (free_blocks <= (windowsz/2)))
+			continue;
+
+		brelse(bitmap_bh);
+		bitmap_bh = read_block_bitmap(sb, group_no);
+		if (!bitmap_bh)
+			goto io_error;
+		/*
+		 * try to allocate block(s) from this group, without a goal(-1).
+		 */
+		grp_alloc_blk = ext2_try_to_allocate_with_rsv(sb, group_no,
+					bitmap_bh, -1, my_rsv, &num);
+		if (grp_alloc_blk >= 0)
+			goto allocated;
+	}
+	/*
+	 * We may end up a bogus earlier ENOSPC error due to
+	 * filesystem is "full" of reservations, but
+	 * there maybe indeed free blocks available on disk
+	 * In this case, we just forget about the reservations
+	 * just do block allocation as without reservations.
+	 */
+	if (my_rsv) {
+		my_rsv = NULL;
+		windowsz = 0;
+		group_no = goal_group;
+		goto retry_alloc;
+	}
+	/* No space left on the device */
+	*errp = -ENOSPC;
+	goto out;
+
+allocated:
+
+	ext2_debug("using block group %d(%d)\n",
+			group_no, gdp->bg_free_blocks_count);
+
+	ret_block = grp_alloc_blk + ext2_group_first_block_no(sb, group_no);
+
+	if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
+	    in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
+	    in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
+		      EXT2_SB(sb)->s_itb_per_group) ||
+	    in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
+		      EXT2_SB(sb)->s_itb_per_group)) {
+		ext2_error(sb, "ext2_new_blocks",
+			    "Allocating block in system zone - "
+			    "blocks from "E2FSBLK", length %lu",
+			    ret_block, num);
+		/*
+		 * ext2_try_to_allocate marked the blocks we allocated as in
+		 * use.  So we may want to selectively mark some of the blocks
+		 * as free
+		 */
+		goto retry_alloc;
+	}
+
+	performed_allocation = 1;
+
+	if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
+		ext2_error(sb, "ext2_new_blocks",
+			    "block("E2FSBLK") >= blocks count(%d) - "
+			    "block_group = %d, es == %p ", ret_block,
+			le32_to_cpu(es->s_blocks_count), group_no, es);
+		goto out;
+	}
+
+	group_adjust_blocks(sb, group_no, gdp, gdp_bh, -num);
+	percpu_counter_sub(&sbi->s_freeblocks_counter, num);
+
+	mark_buffer_dirty(bitmap_bh);
+	if (sb->s_flags & MS_SYNCHRONOUS)
+		sync_dirty_buffer(bitmap_bh);
+
+	*errp = 0;
+	brelse(bitmap_bh);
+	dquot_free_block_nodirty(inode, *count-num);
+	mark_inode_dirty(inode);
+	*count = num;
+	return ret_block;
+
+io_error:
+	*errp = -EIO;
+out:
+	/*
+	 * Undo the block allocation
+	 */
+	if (!performed_allocation) {
+		dquot_free_block_nodirty(inode, *count);
+		mark_inode_dirty(inode);
+	}
+	brelse(bitmap_bh);
+	return 0;
+}
+
+ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp)
+{
+	unsigned long count = 1;
+
+	return ext2_new_blocks(inode, goal, &count, errp);
+}
+
+#ifdef EXT2FS_DEBUG
+
+static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
+
+unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
+{
+	unsigned int i;
+	unsigned long sum = 0;
+
+	if (!map)
+		return (0);
+	for (i = 0; i < numchars; i++)
+		sum += nibblemap[map->b_data[i] & 0xf] +
+			nibblemap[(map->b_data[i] >> 4) & 0xf];
+	return (sum);
+}
+
+#endif  /*  EXT2FS_DEBUG  */
+
+unsigned long ext2_count_free_blocks (struct super_block * sb)
+{
+	struct ext2_group_desc * desc;
+	unsigned long desc_count = 0;
+	int i;
+#ifdef EXT2FS_DEBUG
+	unsigned long bitmap_count, x;
+	struct ext2_super_block *es;
+
+	es = EXT2_SB(sb)->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	desc = NULL;
+	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
+		struct buffer_head *bitmap_bh;
+		desc = ext2_get_group_desc (sb, i, NULL);
+		if (!desc)
+			continue;
+		desc_count += le16_to_cpu(desc->bg_free_blocks_count);
+		bitmap_bh = read_block_bitmap(sb, i);
+		if (!bitmap_bh)
+			continue;
+		
+		x = ext2_count_free(bitmap_bh, sb->s_blocksize);
+		printk ("group %d: stored = %d, counted = %lu\n",
+			i, le16_to_cpu(desc->bg_free_blocks_count), x);
+		bitmap_count += x;
+		brelse(bitmap_bh);
+	}
+	printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n",
+		(long)le32_to_cpu(es->s_free_blocks_count),
+		desc_count, bitmap_count);
+	return bitmap_count;
+#else
+        for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
+                desc = ext2_get_group_desc (sb, i, NULL);
+                if (!desc)
+                        continue;
+                desc_count += le16_to_cpu(desc->bg_free_blocks_count);
+	}
+	return desc_count;
+#endif
+}
+
+static inline int test_root(int a, int b)
+{
+	int num = b;
+
+	while (a > num)
+		num *= b;
+	return num == a;
+}
+
+static int ext2_group_sparse(int group)
+{
+	if (group <= 1)
+		return 1;
+	return (test_root(group, 3) || test_root(group, 5) ||
+		test_root(group, 7));
+}
+
+/**
+ *	ext2_bg_has_super - number of blocks used by the superblock in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the superblock (primary or backup)
+ *	in this group.  Currently this will be only 0 or 1.
+ */
+int ext2_bg_has_super(struct super_block *sb, int group)
+{
+	if (EXT2_HAS_RO_COMPAT_FEATURE(sb,EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
+	    !ext2_group_sparse(group))
+		return 0;
+	return 1;
+}
+
+/**
+ *	ext2_bg_num_gdb - number of blocks used by the group table in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the group descriptor table
+ *	(primary or backup) in this group.  In the future there may be a
+ *	different number of descriptor blocks in each group.
+ */
+unsigned long ext2_bg_num_gdb(struct super_block *sb, int group)
+{
+	return ext2_bg_has_super(sb, group) ? EXT2_SB(sb)->s_gdb_count : 0;
+}
+
diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
new file mode 100644
index 00000000..47cda410
--- /dev/null
+++ b/fs/ext2/dir.c
@@ -0,0 +1,733 @@
+/*
+ *  linux/fs/ext2/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext2 directory handling functions
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * All code that works with directory layout had been switched to pagecache
+ * and moved here. AV
+ */
+
+#include "ext2.h"
+#include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+
+typedef struct ext2_dir_entry_2 ext2_dirent;
+
+/*
+ * Tests against MAX_REC_LEN etc were put in place for 64k block
+ * sizes; if that is not possible on this arch, we can skip
+ * those tests and speed things up.
+ */
+static inline unsigned ext2_rec_len_from_disk(__le16 dlen)
+{
+	unsigned len = le16_to_cpu(dlen);
+
+#if (PAGE_CACHE_SIZE >= 65536)
+	if (len == EXT2_MAX_REC_LEN)
+		return 1 << 16;
+#endif
+	return len;
+}
+
+static inline __le16 ext2_rec_len_to_disk(unsigned len)
+{
+#if (PAGE_CACHE_SIZE >= 65536)
+	if (len == (1 << 16))
+		return cpu_to_le16(EXT2_MAX_REC_LEN);
+	else
+		BUG_ON(len > (1 << 16));
+#endif
+	return cpu_to_le16(len);
+}
+
+/*
+ * ext2 uses block-sized chunks. Arguably, sector-sized ones would be
+ * more robust, but we have what we have
+ */
+static inline unsigned ext2_chunk_size(struct inode *inode)
+{
+	return inode->i_sb->s_blocksize;
+}
+
+static inline void ext2_put_page(struct page *page)
+{
+	kunmap(page);
+	page_cache_release(page);
+}
+
+static inline unsigned long dir_pages(struct inode *inode)
+{
+	return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
+}
+
+/*
+ * Return the offset into page `page_nr' of the last valid
+ * byte in that page, plus one.
+ */
+static unsigned
+ext2_last_byte(struct inode *inode, unsigned long page_nr)
+{
+	unsigned last_byte = inode->i_size;
+
+	last_byte -= page_nr << PAGE_CACHE_SHIFT;
+	if (last_byte > PAGE_CACHE_SIZE)
+		last_byte = PAGE_CACHE_SIZE;
+	return last_byte;
+}
+
+static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *dir = mapping->host;
+	int err = 0;
+
+	dir->i_version++;
+	block_write_end(NULL, mapping, pos, len, len, page, NULL);
+
+	if (pos+len > dir->i_size) {
+		i_size_write(dir, pos+len);
+		mark_inode_dirty(dir);
+	}
+
+	if (IS_DIRSYNC(dir)) {
+		err = write_one_page(page, 1);
+		if (!err)
+			err = sync_inode_metadata(dir, 1);
+	} else {
+		unlock_page(page);
+	}
+
+	return err;
+}
+
+static void ext2_check_page(struct page *page, int quiet)
+{
+	struct inode *dir = page->mapping->host;
+	struct super_block *sb = dir->i_sb;
+	unsigned chunk_size = ext2_chunk_size(dir);
+	char *kaddr = page_address(page);
+	u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count);
+	unsigned offs, rec_len;
+	unsigned limit = PAGE_CACHE_SIZE;
+	ext2_dirent *p;
+	char *error;
+
+	if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
+		limit = dir->i_size & ~PAGE_CACHE_MASK;
+		if (limit & (chunk_size - 1))
+			goto Ebadsize;
+		if (!limit)
+			goto out;
+	}
+	for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) {
+		p = (ext2_dirent *)(kaddr + offs);
+		rec_len = ext2_rec_len_from_disk(p->rec_len);
+
+		if (unlikely(rec_len < EXT2_DIR_REC_LEN(1)))
+			goto Eshort;
+		if (unlikely(rec_len & 3))
+			goto Ealign;
+		if (unlikely(rec_len < EXT2_DIR_REC_LEN(p->name_len)))
+			goto Enamelen;
+		if (unlikely(((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)))
+			goto Espan;
+		if (unlikely(le32_to_cpu(p->inode) > max_inumber))
+			goto Einumber;
+	}
+	if (offs != limit)
+		goto Eend;
+out:
+	SetPageChecked(page);
+	return;
+
+	/* Too bad, we had an error */
+
+Ebadsize:
+	if (!quiet)
+		ext2_error(sb, __func__,
+			"size of directory #%lu is not a multiple "
+			"of chunk size", dir->i_ino);
+	goto fail;
+Eshort:
+	error = "rec_len is smaller than minimal";
+	goto bad_entry;
+Ealign:
+	error = "unaligned directory entry";
+	goto bad_entry;
+Enamelen:
+	error = "rec_len is too small for name_len";
+	goto bad_entry;
+Espan:
+	error = "directory entry across blocks";
+	goto bad_entry;
+Einumber:
+	error = "inode out of bounds";
+bad_entry:
+	if (!quiet)
+		ext2_error(sb, __func__, "bad entry in directory #%lu: : %s - "
+			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
+			dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
+			(unsigned long) le32_to_cpu(p->inode),
+			rec_len, p->name_len);
+	goto fail;
+Eend:
+	if (!quiet) {
+		p = (ext2_dirent *)(kaddr + offs);
+		ext2_error(sb, "ext2_check_page",
+			"entry in directory #%lu spans the page boundary"
+			"offset=%lu, inode=%lu",
+			dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
+			(unsigned long) le32_to_cpu(p->inode));
+	}
+fail:
+	SetPageChecked(page);
+	SetPageError(page);
+}
+
+static struct page * ext2_get_page(struct inode *dir, unsigned long n,
+				   int quiet)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct page *page = read_mapping_page(mapping, n, NULL);
+	if (!IS_ERR(page)) {
+		kmap(page);
+		if (!PageChecked(page))
+			ext2_check_page(page, quiet);
+		if (PageError(page))
+			goto fail;
+	}
+	return page;
+
+fail:
+	ext2_put_page(page);
+	return ERR_PTR(-EIO);
+}
+
+/*
+ * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure.
+ *
+ * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller.
+ */
+static inline int ext2_match (int len, const char * const name,
+					struct ext2_dir_entry_2 * de)
+{
+	if (len != de->name_len)
+		return 0;
+	if (!de->inode)
+		return 0;
+	return !memcmp(name, de->name, len);
+}
+
+/*
+ * p is at least 6 bytes before the end of page
+ */
+static inline ext2_dirent *ext2_next_entry(ext2_dirent *p)
+{
+	return (ext2_dirent *)((char *)p +
+			ext2_rec_len_from_disk(p->rec_len));
+}
+
+static inline unsigned 
+ext2_validate_entry(char *base, unsigned offset, unsigned mask)
+{
+	ext2_dirent *de = (ext2_dirent*)(base + offset);
+	ext2_dirent *p = (ext2_dirent*)(base + (offset&mask));
+	while ((char*)p < (char*)de) {
+		if (p->rec_len == 0)
+			break;
+		p = ext2_next_entry(p);
+	}
+	return (char *)p - base;
+}
+
+static unsigned char ext2_filetype_table[EXT2_FT_MAX] = {
+	[EXT2_FT_UNKNOWN]	= DT_UNKNOWN,
+	[EXT2_FT_REG_FILE]	= DT_REG,
+	[EXT2_FT_DIR]		= DT_DIR,
+	[EXT2_FT_CHRDEV]	= DT_CHR,
+	[EXT2_FT_BLKDEV]	= DT_BLK,
+	[EXT2_FT_FIFO]		= DT_FIFO,
+	[EXT2_FT_SOCK]		= DT_SOCK,
+	[EXT2_FT_SYMLINK]	= DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= EXT2_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= EXT2_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= EXT2_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= EXT2_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= EXT2_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= EXT2_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= EXT2_FT_SYMLINK,
+};
+
+static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode)
+{
+	mode_t mode = inode->i_mode;
+	if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
+		de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
+	else
+		de->file_type = 0;
+}
+
+static int
+ext2_readdir (struct file * filp, void * dirent, filldir_t filldir)
+{
+	loff_t pos = filp->f_pos;
+	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct super_block *sb = inode->i_sb;
+	unsigned int offset = pos & ~PAGE_CACHE_MASK;
+	unsigned long n = pos >> PAGE_CACHE_SHIFT;
+	unsigned long npages = dir_pages(inode);
+	unsigned chunk_mask = ~(ext2_chunk_size(inode)-1);
+	unsigned char *types = NULL;
+	int need_revalidate = filp->f_version != inode->i_version;
+
+	if (pos > inode->i_size - EXT2_DIR_REC_LEN(1))
+		return 0;
+
+	if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE))
+		types = ext2_filetype_table;
+
+	for ( ; n < npages; n++, offset = 0) {
+		char *kaddr, *limit;
+		ext2_dirent *de;
+		struct page *page = ext2_get_page(inode, n, 0);
+
+		if (IS_ERR(page)) {
+			ext2_error(sb, __func__,
+				   "bad page in #%lu",
+				   inode->i_ino);
+			filp->f_pos += PAGE_CACHE_SIZE - offset;
+			return PTR_ERR(page);
+		}
+		kaddr = page_address(page);
+		if (unlikely(need_revalidate)) {
+			if (offset) {
+				offset = ext2_validate_entry(kaddr, offset, chunk_mask);
+				filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
+			}
+			filp->f_version = inode->i_version;
+			need_revalidate = 0;
+		}
+		de = (ext2_dirent *)(kaddr+offset);
+		limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1);
+		for ( ;(char*)de <= limit; de = ext2_next_entry(de)) {
+			if (de->rec_len == 0) {
+				ext2_error(sb, __func__,
+					"zero-length directory entry");
+				ext2_put_page(page);
+				return -EIO;
+			}
+			if (de->inode) {
+				int over;
+				unsigned char d_type = DT_UNKNOWN;
+
+				if (types && de->file_type < EXT2_FT_MAX)
+					d_type = types[de->file_type];
+
+				offset = (char *)de - kaddr;
+				over = filldir(dirent, de->name, de->name_len,
+						(n<<PAGE_CACHE_SHIFT) | offset,
+						le32_to_cpu(de->inode), d_type);
+				if (over) {
+					ext2_put_page(page);
+					return 0;
+				}
+			}
+			filp->f_pos += ext2_rec_len_from_disk(de->rec_len);
+		}
+		ext2_put_page(page);
+	}
+	return 0;
+}
+
+/*
+ *	ext2_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the page in which the entry was found (as a parameter - res_page),
+ * and the entry itself. Page is returned mapped and unlocked.
+ * Entry is guaranteed to be valid.
+ */
+struct ext2_dir_entry_2 *ext2_find_entry (struct inode * dir,
+			struct qstr *child, struct page ** res_page)
+{
+	const char *name = child->name;
+	int namelen = child->len;
+	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
+	unsigned long start, n;
+	unsigned long npages = dir_pages(dir);
+	struct page *page = NULL;
+	struct ext2_inode_info *ei = EXT2_I(dir);
+	ext2_dirent * de;
+	int dir_has_error = 0;
+
+	if (npages == 0)
+		goto out;
+
+	/* OFFSET_CACHE */
+	*res_page = NULL;
+
+	start = ei->i_dir_start_lookup;
+	if (start >= npages)
+		start = 0;
+	n = start;
+	do {
+		char *kaddr;
+		page = ext2_get_page(dir, n, dir_has_error);
+		if (!IS_ERR(page)) {
+			kaddr = page_address(page);
+			de = (ext2_dirent *) kaddr;
+			kaddr += ext2_last_byte(dir, n) - reclen;
+			while ((char *) de <= kaddr) {
+				if (de->rec_len == 0) {
+					ext2_error(dir->i_sb, __func__,
+						"zero-length directory entry");
+					ext2_put_page(page);
+					goto out;
+				}
+				if (ext2_match (namelen, name, de))
+					goto found;
+				de = ext2_next_entry(de);
+			}
+			ext2_put_page(page);
+		} else
+			dir_has_error = 1;
+
+		if (++n >= npages)
+			n = 0;
+		/* next page is past the blocks we've got */
+		if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) {
+			ext2_error(dir->i_sb, __func__,
+				"dir %lu size %lld exceeds block count %llu",
+				dir->i_ino, dir->i_size,
+				(unsigned long long)dir->i_blocks);
+			goto out;
+		}
+	} while (n != start);
+out:
+	return NULL;
+
+found:
+	*res_page = page;
+	ei->i_dir_start_lookup = n;
+	return de;
+}
+
+struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
+{
+	struct page *page = ext2_get_page(dir, 0, 0);
+	ext2_dirent *de = NULL;
+
+	if (!IS_ERR(page)) {
+		de = ext2_next_entry((ext2_dirent *) page_address(page));
+		*p = page;
+	}
+	return de;
+}
+
+ino_t ext2_inode_by_name(struct inode *dir, struct qstr *child)
+{
+	ino_t res = 0;
+	struct ext2_dir_entry_2 *de;
+	struct page *page;
+	
+	de = ext2_find_entry (dir, child, &page);
+	if (de) {
+		res = le32_to_cpu(de->inode);
+		ext2_put_page(page);
+	}
+	return res;
+}
+
+static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	return __block_write_begin(page, pos, len, ext2_get_block);
+}
+
+/* Releases the page */
+void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
+		   struct page *page, struct inode *inode, int update_times)
+{
+	loff_t pos = page_offset(page) +
+			(char *) de - (char *) page_address(page);
+	unsigned len = ext2_rec_len_from_disk(de->rec_len);
+	int err;
+
+	lock_page(page);
+	err = ext2_prepare_chunk(page, pos, len);
+	BUG_ON(err);
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext2_set_de_type(de, inode);
+	err = ext2_commit_chunk(page, pos, len);
+	ext2_put_page(page);
+	if (update_times)
+		dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
+	mark_inode_dirty(dir);
+}
+
+/*
+ *	Parent is locked.
+ */
+int ext2_add_link (struct dentry *dentry, struct inode *inode)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	unsigned chunk_size = ext2_chunk_size(dir);
+	unsigned reclen = EXT2_DIR_REC_LEN(namelen);
+	unsigned short rec_len, name_len;
+	struct page *page = NULL;
+	ext2_dirent * de;
+	unsigned long npages = dir_pages(dir);
+	unsigned long n;
+	char *kaddr;
+	loff_t pos;
+	int err;
+
+	/*
+	 * We take care of directory expansion in the same loop.
+	 * This code plays outside i_size, so it locks the page
+	 * to protect that region.
+	 */
+	for (n = 0; n <= npages; n++) {
+		char *dir_end;
+
+		page = ext2_get_page(dir, n, 0);
+		err = PTR_ERR(page);
+		if (IS_ERR(page))
+			goto out;
+		lock_page(page);
+		kaddr = page_address(page);
+		dir_end = kaddr + ext2_last_byte(dir, n);
+		de = (ext2_dirent *)kaddr;
+		kaddr += PAGE_CACHE_SIZE - reclen;
+		while ((char *)de <= kaddr) {
+			if ((char *)de == dir_end) {
+				/* We hit i_size */
+				name_len = 0;
+				rec_len = chunk_size;
+				de->rec_len = ext2_rec_len_to_disk(chunk_size);
+				de->inode = 0;
+				goto got_it;
+			}
+			if (de->rec_len == 0) {
+				ext2_error(dir->i_sb, __func__,
+					"zero-length directory entry");
+				err = -EIO;
+				goto out_unlock;
+			}
+			err = -EEXIST;
+			if (ext2_match (namelen, name, de))
+				goto out_unlock;
+			name_len = EXT2_DIR_REC_LEN(de->name_len);
+			rec_len = ext2_rec_len_from_disk(de->rec_len);
+			if (!de->inode && rec_len >= reclen)
+				goto got_it;
+			if (rec_len >= name_len + reclen)
+				goto got_it;
+			de = (ext2_dirent *) ((char *) de + rec_len);
+		}
+		unlock_page(page);
+		ext2_put_page(page);
+	}
+	BUG();
+	return -EINVAL;
+
+got_it:
+	pos = page_offset(page) +
+		(char*)de - (char*)page_address(page);
+	err = ext2_prepare_chunk(page, pos, rec_len);
+	if (err)
+		goto out_unlock;
+	if (de->inode) {
+		ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len);
+		de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len);
+		de->rec_len = ext2_rec_len_to_disk(name_len);
+		de = de1;
+	}
+	de->name_len = namelen;
+	memcpy(de->name, name, namelen);
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext2_set_de_type (de, inode);
+	err = ext2_commit_chunk(page, pos, rec_len);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+	EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL;
+	mark_inode_dirty(dir);
+	/* OFFSET_CACHE */
+out_put:
+	ext2_put_page(page);
+out:
+	return err;
+out_unlock:
+	unlock_page(page);
+	goto out_put;
+}
+
+/*
+ * ext2_delete_entry deletes a directory entry by merging it with the
+ * previous entry. Page is up-to-date. Releases the page.
+ */
+int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page )
+{
+	struct inode *inode = page->mapping->host;
+	char *kaddr = page_address(page);
+	unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1);
+	unsigned to = ((char *)dir - kaddr) +
+				ext2_rec_len_from_disk(dir->rec_len);
+	loff_t pos;
+	ext2_dirent * pde = NULL;
+	ext2_dirent * de = (ext2_dirent *) (kaddr + from);
+	int err;
+
+	while ((char*)de < (char*)dir) {
+		if (de->rec_len == 0) {
+			ext2_error(inode->i_sb, __func__,
+				"zero-length directory entry");
+			err = -EIO;
+			goto out;
+		}
+		pde = de;
+		de = ext2_next_entry(de);
+	}
+	if (pde)
+		from = (char*)pde - (char*)page_address(page);
+	pos = page_offset(page) + from;
+	lock_page(page);
+	err = ext2_prepare_chunk(page, pos, to - from);
+	BUG_ON(err);
+	if (pde)
+		pde->rec_len = ext2_rec_len_to_disk(to - from);
+	dir->inode = 0;
+	err = ext2_commit_chunk(page, pos, to - from);
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+	EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL;
+	mark_inode_dirty(inode);
+out:
+	ext2_put_page(page);
+	return err;
+}
+
+/*
+ * Set the first fragment of directory.
+ */
+int ext2_make_empty(struct inode *inode, struct inode *parent)
+{
+	struct page *page = grab_cache_page(inode->i_mapping, 0);
+	unsigned chunk_size = ext2_chunk_size(inode);
+	struct ext2_dir_entry_2 * de;
+	int err;
+	void *kaddr;
+
+	if (!page)
+		return -ENOMEM;
+
+	err = ext2_prepare_chunk(page, 0, chunk_size);
+	if (err) {
+		unlock_page(page);
+		goto fail;
+	}
+	kaddr = kmap_atomic(page, KM_USER0);
+	memset(kaddr, 0, chunk_size);
+	de = (struct ext2_dir_entry_2 *)kaddr;
+	de->name_len = 1;
+	de->rec_len = ext2_rec_len_to_disk(EXT2_DIR_REC_LEN(1));
+	memcpy (de->name, ".\0\0", 4);
+	de->inode = cpu_to_le32(inode->i_ino);
+	ext2_set_de_type (de, inode);
+
+	de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1));
+	de->name_len = 2;
+	de->rec_len = ext2_rec_len_to_disk(chunk_size - EXT2_DIR_REC_LEN(1));
+	de->inode = cpu_to_le32(parent->i_ino);
+	memcpy (de->name, "..\0", 4);
+	ext2_set_de_type (de, inode);
+	kunmap_atomic(kaddr, KM_USER0);
+	err = ext2_commit_chunk(page, 0, chunk_size);
+fail:
+	page_cache_release(page);
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+int ext2_empty_dir (struct inode * inode)
+{
+	struct page *page = NULL;
+	unsigned long i, npages = dir_pages(inode);
+	int dir_has_error = 0;
+
+	for (i = 0; i < npages; i++) {
+		char *kaddr;
+		ext2_dirent * de;
+		page = ext2_get_page(inode, i, dir_has_error);
+
+		if (IS_ERR(page)) {
+			dir_has_error = 1;
+			continue;
+		}
+
+		kaddr = page_address(page);
+		de = (ext2_dirent *)kaddr;
+		kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1);
+
+		while ((char *)de <= kaddr) {
+			if (de->rec_len == 0) {
+				ext2_error(inode->i_sb, __func__,
+					"zero-length directory entry");
+				printk("kaddr=%p, de=%p\n", kaddr, de);
+				goto not_empty;
+			}
+			if (de->inode != 0) {
+				/* check for . and .. */
+				if (de->name[0] != '.')
+					goto not_empty;
+				if (de->name_len > 2)
+					goto not_empty;
+				if (de->name_len < 2) {
+					if (de->inode !=
+					    cpu_to_le32(inode->i_ino))
+						goto not_empty;
+				} else if (de->name[1] != '.')
+					goto not_empty;
+			}
+			de = ext2_next_entry(de);
+		}
+		ext2_put_page(page);
+	}
+	return 1;
+
+not_empty:
+	ext2_put_page(page);
+	return 0;
+}
+
+const struct file_operations ext2_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.readdir	= ext2_readdir,
+	.unlocked_ioctl = ext2_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext2_compat_ioctl,
+#endif
+	.fsync		= ext2_fsync,
+};
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
new file mode 100644
index 00000000..645be9e7
--- /dev/null
+++ b/fs/ext2/ext2.h
@@ -0,0 +1,182 @@
+#include <linux/fs.h>
+#include <linux/ext2_fs.h>
+
+/*
+ * ext2 mount options
+ */
+struct ext2_mount_options {
+	unsigned long s_mount_opt;
+	uid_t s_resuid;
+	gid_t s_resgid;
+};
+
+/*
+ * second extended file system inode data in memory
+ */
+struct ext2_inode_info {
+	__le32	i_data[15];
+	__u32	i_flags;
+	__u32	i_faddr;
+	__u8	i_frag_no;
+	__u8	i_frag_size;
+	__u16	i_state;
+	__u32	i_file_acl;
+	__u32	i_dir_acl;
+	__u32	i_dtime;
+
+	/*
+	 * i_block_group is the number of the block group which contains
+	 * this file's inode.  Constant across the lifetime of the inode,
+	 * it is used for making block allocation decisions - we try to
+	 * place a file's data blocks near its inode block, and new inodes
+	 * near to their parent directory's inode.
+	 */
+	__u32	i_block_group;
+
+	/* block reservation info */
+	struct ext2_block_alloc_info *i_block_alloc_info;
+
+	__u32	i_dir_start_lookup;
+#ifdef CONFIG_EXT2_FS_XATTR
+	/*
+	 * Extended attributes can be read independently of the main file
+	 * data. Taking i_mutex even when reading would cause contention
+	 * between readers of EAs and writers of regular file data, so
+	 * instead we synchronize on xattr_sem when reading or changing
+	 * EAs.
+	 */
+	struct rw_semaphore xattr_sem;
+#endif
+	rwlock_t i_meta_lock;
+
+	/*
+	 * truncate_mutex is for serialising ext2_truncate() against
+	 * ext2_getblock().  It also protects the internals of the inode's
+	 * reservation data structures: ext2_reserve_window and
+	 * ext2_reserve_window_node.
+	 */
+	struct mutex truncate_mutex;
+	struct inode	vfs_inode;
+	struct list_head i_orphan;	/* unlinked but open inodes */
+};
+
+/*
+ * Inode dynamic state flags
+ */
+#define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
+
+
+/*
+ * Function prototypes
+ */
+
+/*
+ * Ok, these declarations are also in <linux/kernel.h> but none of the
+ * ext2 source programs needs to include it so they are duplicated here.
+ */
+
+static inline struct ext2_inode_info *EXT2_I(struct inode *inode)
+{
+	return container_of(inode, struct ext2_inode_info, vfs_inode);
+}
+
+/* balloc.c */
+extern int ext2_bg_has_super(struct super_block *sb, int group);
+extern unsigned long ext2_bg_num_gdb(struct super_block *sb, int group);
+extern ext2_fsblk_t ext2_new_block(struct inode *, unsigned long, int *);
+extern ext2_fsblk_t ext2_new_blocks(struct inode *, unsigned long,
+				unsigned long *, int *);
+extern void ext2_free_blocks (struct inode *, unsigned long,
+			      unsigned long);
+extern unsigned long ext2_count_free_blocks (struct super_block *);
+extern unsigned long ext2_count_dirs (struct super_block *);
+extern void ext2_check_blocks_bitmap (struct super_block *);
+extern struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
+						    unsigned int block_group,
+						    struct buffer_head ** bh);
+extern void ext2_discard_reservation (struct inode *);
+extern int ext2_should_retry_alloc(struct super_block *sb, int *retries);
+extern void ext2_init_block_alloc_info(struct inode *);
+extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_window_node *rsv);
+
+/* dir.c */
+extern int ext2_add_link (struct dentry *, struct inode *);
+extern ino_t ext2_inode_by_name(struct inode *, struct qstr *);
+extern int ext2_make_empty(struct inode *, struct inode *);
+extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct qstr *, struct page **);
+extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);
+extern int ext2_empty_dir (struct inode *);
+extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **);
+extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int);
+
+/* ialloc.c */
+extern struct inode * ext2_new_inode (struct inode *, int, const struct qstr *);
+extern void ext2_free_inode (struct inode *);
+extern unsigned long ext2_count_free_inodes (struct super_block *);
+extern void ext2_check_inodes_bitmap (struct super_block *);
+extern unsigned long ext2_count_free (struct buffer_head *, unsigned);
+
+/* inode.c */
+extern struct inode *ext2_iget (struct super_block *, unsigned long);
+extern int ext2_write_inode (struct inode *, struct writeback_control *);
+extern void ext2_evict_inode(struct inode *);
+extern int ext2_get_block(struct inode *, sector_t, struct buffer_head *, int);
+extern int ext2_setattr (struct dentry *, struct iattr *);
+extern void ext2_set_inode_flags(struct inode *inode);
+extern void ext2_get_inode_flags(struct ext2_inode_info *);
+extern int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		       u64 start, u64 len);
+
+/* ioctl.c */
+extern long ext2_ioctl(struct file *, unsigned int, unsigned long);
+extern long ext2_compat_ioctl(struct file *, unsigned int, unsigned long);
+
+/* namei.c */
+struct dentry *ext2_get_parent(struct dentry *child);
+
+/* super.c */
+extern void ext2_error (struct super_block *, const char *, const char *, ...)
+	__attribute__ ((format (printf, 3, 4)));
+extern void ext2_msg(struct super_block *, const char *, const char *, ...)
+	__attribute__ ((format (printf, 3, 4)));
+extern void ext2_update_dynamic_rev (struct super_block *sb);
+extern void ext2_write_super (struct super_block *);
+
+/*
+ * Inodes and files operations
+ */
+
+/* dir.c */
+extern const struct file_operations ext2_dir_operations;
+
+/* file.c */
+extern int ext2_fsync(struct file *file, int datasync);
+extern const struct inode_operations ext2_file_inode_operations;
+extern const struct file_operations ext2_file_operations;
+extern const struct file_operations ext2_xip_file_operations;
+
+/* inode.c */
+extern const struct address_space_operations ext2_aops;
+extern const struct address_space_operations ext2_aops_xip;
+extern const struct address_space_operations ext2_nobh_aops;
+
+/* namei.c */
+extern const struct inode_operations ext2_dir_inode_operations;
+extern const struct inode_operations ext2_special_inode_operations;
+
+/* symlink.c */
+extern const struct inode_operations ext2_fast_symlink_inode_operations;
+extern const struct inode_operations ext2_symlink_inode_operations;
+
+static inline ext2_fsblk_t
+ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
+{
+	return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
+		le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
+}
+
+#define ext2_set_bit	__test_and_set_bit_le
+#define ext2_clear_bit	__test_and_clear_bit_le
+#define ext2_test_bit	test_bit_le
+#define ext2_find_first_zero_bit	find_first_zero_bit_le
+#define ext2_find_next_zero_bit		find_next_zero_bit_le
diff --git a/fs/ext2/file.c b/fs/ext2/file.c
new file mode 100644
index 00000000..49eec945
--- /dev/null
+++ b/fs/ext2/file.c
@@ -0,0 +1,107 @@
+/*
+ *  linux/fs/ext2/file.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/file.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext2 fs regular file handling primitives
+ *
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ * 	(jj@sunsite.ms.mff.cuni.cz)
+ */
+
+#include <linux/time.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Called when filp is released. This happens when all file descriptors
+ * for a single struct file are closed. Note that different open() calls
+ * for the same file yield different struct file structures.
+ */
+static int ext2_release_file (struct inode * inode, struct file * filp)
+{
+	if (filp->f_mode & FMODE_WRITE) {
+		mutex_lock(&EXT2_I(inode)->truncate_mutex);
+		ext2_discard_reservation(inode);
+		mutex_unlock(&EXT2_I(inode)->truncate_mutex);
+	}
+	return 0;
+}
+
+int ext2_fsync(struct file *file, int datasync)
+{
+	int ret;
+	struct super_block *sb = file->f_mapping->host->i_sb;
+	struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
+
+	ret = generic_file_fsync(file, datasync);
+	if (ret == -EIO || test_and_clear_bit(AS_EIO, &mapping->flags)) {
+		/* We don't really know where the IO error happened... */
+		ext2_error(sb, __func__,
+			   "detected IO error when writing metadata buffers");
+		ret = -EIO;
+	}
+	return ret;
+}
+
+/*
+ * We have mostly NULL's here: the current defaults are ok for
+ * the ext2 filesystem.
+ */
+const struct file_operations ext2_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= do_sync_read,
+	.write		= do_sync_write,
+	.aio_read	= generic_file_aio_read,
+	.aio_write	= generic_file_aio_write,
+	.unlocked_ioctl = ext2_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext2_compat_ioctl,
+#endif
+	.mmap		= generic_file_mmap,
+	.open		= dquot_file_open,
+	.release	= ext2_release_file,
+	.fsync		= ext2_fsync,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= generic_file_splice_write,
+};
+
+#ifdef CONFIG_EXT2_FS_XIP
+const struct file_operations ext2_xip_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= xip_file_read,
+	.write		= xip_file_write,
+	.unlocked_ioctl = ext2_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext2_compat_ioctl,
+#endif
+	.mmap		= xip_file_mmap,
+	.open		= dquot_file_open,
+	.release	= ext2_release_file,
+	.fsync		= ext2_fsync,
+};
+#endif
+
+const struct inode_operations ext2_file_inode_operations = {
+#ifdef CONFIG_EXT2_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext2_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+	.setattr	= ext2_setattr,
+	.check_acl	= ext2_check_acl,
+	.fiemap		= ext2_fiemap,
+};
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
new file mode 100644
index 00000000..ee9ed319
--- /dev/null
+++ b/fs/ext2/ialloc.c
@@ -0,0 +1,674 @@
+/*
+ *  linux/fs/ext2/ialloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  BSD ufs-inspired inode and directory allocation by 
+ *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/quotaops.h>
+#include <linux/sched.h>
+#include <linux/backing-dev.h>
+#include <linux/buffer_head.h>
+#include <linux/random.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * ialloc.c contains the inodes allocation and deallocation routines
+ */
+
+/*
+ * The free inodes are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.
+ */
+
+
+/*
+ * Read the inode allocation bitmap for a given block_group, reading
+ * into the specified slot in the superblock's bitmap cache.
+ *
+ * Return buffer_head of bitmap on success or NULL.
+ */
+static struct buffer_head *
+read_inode_bitmap(struct super_block * sb, unsigned long block_group)
+{
+	struct ext2_group_desc *desc;
+	struct buffer_head *bh = NULL;
+
+	desc = ext2_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		goto error_out;
+
+	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
+	if (!bh)
+		ext2_error(sb, "read_inode_bitmap",
+			    "Cannot read inode bitmap - "
+			    "block_group = %lu, inode_bitmap = %u",
+			    block_group, le32_to_cpu(desc->bg_inode_bitmap));
+error_out:
+	return bh;
+}
+
+static void ext2_release_inode(struct super_block *sb, int group, int dir)
+{
+	struct ext2_group_desc * desc;
+	struct buffer_head *bh;
+
+	desc = ext2_get_group_desc(sb, group, &bh);
+	if (!desc) {
+		ext2_error(sb, "ext2_release_inode",
+			"can't get descriptor for group %d", group);
+		return;
+	}
+
+	spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
+	le16_add_cpu(&desc->bg_free_inodes_count, 1);
+	if (dir)
+		le16_add_cpu(&desc->bg_used_dirs_count, -1);
+	spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
+	if (dir)
+		percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
+	sb->s_dirt = 1;
+	mark_buffer_dirty(bh);
+}
+
+/*
+ * NOTE! When we get the inode, we're the only people
+ * that have access to it, and as such there are no
+ * race conditions we have to worry about. The inode
+ * is not on the hash-lists, and it cannot be reached
+ * through the filesystem because the directory entry
+ * has been deleted earlier.
+ *
+ * HOWEVER: we must make sure that we get no aliases,
+ * which means that we have to call "clear_inode()"
+ * _before_ we mark the inode not in use in the inode
+ * bitmaps. Otherwise a newly created file might use
+ * the same inode number (not actually the same pointer
+ * though), and then we'd have two inodes sharing the
+ * same inode number and space on the harddisk.
+ */
+void ext2_free_inode (struct inode * inode)
+{
+	struct super_block * sb = inode->i_sb;
+	int is_directory;
+	unsigned long ino;
+	struct buffer_head *bitmap_bh;
+	unsigned long block_group;
+	unsigned long bit;
+	struct ext2_super_block * es;
+
+	ino = inode->i_ino;
+	ext2_debug ("freeing inode %lu\n", ino);
+
+	/*
+	 * Note: we must free any quota before locking the superblock,
+	 * as writing the quota to disk may need the lock as well.
+	 */
+	/* Quota is already initialized in iput() */
+	ext2_xattr_delete_inode(inode);
+	dquot_free_inode(inode);
+	dquot_drop(inode);
+
+	es = EXT2_SB(sb)->s_es;
+	is_directory = S_ISDIR(inode->i_mode);
+
+	if (ino < EXT2_FIRST_INO(sb) ||
+	    ino > le32_to_cpu(es->s_inodes_count)) {
+		ext2_error (sb, "ext2_free_inode",
+			    "reserved or nonexistent inode %lu", ino);
+		return;
+	}
+	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
+	bitmap_bh = read_inode_bitmap(sb, block_group);
+	if (!bitmap_bh)
+		return;
+
+	/* Ok, now we can actually update the inode bitmaps.. */
+	if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
+				bit, (void *) bitmap_bh->b_data))
+		ext2_error (sb, "ext2_free_inode",
+			      "bit already cleared for inode %lu", ino);
+	else
+		ext2_release_inode(sb, block_group, is_directory);
+	mark_buffer_dirty(bitmap_bh);
+	if (sb->s_flags & MS_SYNCHRONOUS)
+		sync_dirty_buffer(bitmap_bh);
+
+	brelse(bitmap_bh);
+}
+
+/*
+ * We perform asynchronous prereading of the new inode's inode block when
+ * we create the inode, in the expectation that the inode will be written
+ * back soon.  There are two reasons:
+ *
+ * - When creating a large number of files, the async prereads will be
+ *   nicely merged into large reads
+ * - When writing out a large number of inodes, we don't need to keep on
+ *   stalling the writes while we read the inode block.
+ *
+ * FIXME: ext2_get_group_desc() needs to be simplified.
+ */
+static void ext2_preread_inode(struct inode *inode)
+{
+	unsigned long block_group;
+	unsigned long offset;
+	unsigned long block;
+	struct ext2_group_desc * gdp;
+	struct backing_dev_info *bdi;
+
+	bdi = inode->i_mapping->backing_dev_info;
+	if (bdi_read_congested(bdi))
+		return;
+	if (bdi_write_congested(bdi))
+		return;
+
+	block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
+	gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
+	if (gdp == NULL)
+		return;
+
+	/*
+	 * Figure out the offset within the block group inode table
+	 */
+	offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
+				EXT2_INODE_SIZE(inode->i_sb);
+	block = le32_to_cpu(gdp->bg_inode_table) +
+				(offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
+	sb_breadahead(inode->i_sb, block);
+}
+
+/*
+ * There are two policies for allocating an inode.  If the new inode is
+ * a directory, then a forward search is made for a block group with both
+ * free space and a low directory-to-inode ratio; if that fails, then of
+ * the groups with above-average free space, that group with the fewest
+ * directories already is chosen.
+ *
+ * For other inodes, search forward from the parent directory\'s block
+ * group to find a free inode.
+ */
+static int find_group_dir(struct super_block *sb, struct inode *parent)
+{
+	int ngroups = EXT2_SB(sb)->s_groups_count;
+	int avefreei = ext2_count_free_inodes(sb) / ngroups;
+	struct ext2_group_desc *desc, *best_desc = NULL;
+	int group, best_group = -1;
+
+	for (group = 0; group < ngroups; group++) {
+		desc = ext2_get_group_desc (sb, group, NULL);
+		if (!desc || !desc->bg_free_inodes_count)
+			continue;
+		if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
+			continue;
+		if (!best_desc || 
+		    (le16_to_cpu(desc->bg_free_blocks_count) >
+		     le16_to_cpu(best_desc->bg_free_blocks_count))) {
+			best_group = group;
+			best_desc = desc;
+		}
+	}
+	if (!best_desc)
+		return -1;
+
+	return best_group;
+}
+
+/* 
+ * Orlov's allocator for directories. 
+ * 
+ * We always try to spread first-level directories.
+ *
+ * If there are blockgroups with both free inodes and free blocks counts 
+ * not worse than average we return one with smallest directory count. 
+ * Otherwise we simply return a random group. 
+ * 
+ * For the rest rules look so: 
+ * 
+ * It's OK to put directory into a group unless 
+ * it has too many directories already (max_dirs) or 
+ * it has too few free inodes left (min_inodes) or 
+ * it has too few free blocks left (min_blocks) or 
+ * it's already running too large debt (max_debt). 
+ * Parent's group is preferred, if it doesn't satisfy these 
+ * conditions we search cyclically through the rest. If none 
+ * of the groups look good we just look for a group with more 
+ * free inodes than average (starting at parent's group). 
+ * 
+ * Debt is incremented each time we allocate a directory and decremented 
+ * when we allocate an inode, within 0--255. 
+ */ 
+
+#define INODE_COST 64
+#define BLOCK_COST 256
+
+static int find_group_orlov(struct super_block *sb, struct inode *parent)
+{
+	int parent_group = EXT2_I(parent)->i_block_group;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+	int ngroups = sbi->s_groups_count;
+	int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
+	int freei;
+	int avefreei;
+	int free_blocks;
+	int avefreeb;
+	int blocks_per_dir;
+	int ndirs;
+	int max_debt, max_dirs, min_blocks, min_inodes;
+	int group = -1, i;
+	struct ext2_group_desc *desc;
+
+	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
+	avefreei = freei / ngroups;
+	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+	avefreeb = free_blocks / ngroups;
+	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
+
+	if ((parent == sb->s_root->d_inode) ||
+	    (EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
+		struct ext2_group_desc *best_desc = NULL;
+		int best_ndir = inodes_per_group;
+		int best_group = -1;
+
+		get_random_bytes(&group, sizeof(group));
+		parent_group = (unsigned)group % ngroups;
+		for (i = 0; i < ngroups; i++) {
+			group = (parent_group + i) % ngroups;
+			desc = ext2_get_group_desc (sb, group, NULL);
+			if (!desc || !desc->bg_free_inodes_count)
+				continue;
+			if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
+				continue;
+			if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
+				continue;
+			if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
+				continue;
+			best_group = group;
+			best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
+			best_desc = desc;
+		}
+		if (best_group >= 0) {
+			desc = best_desc;
+			group = best_group;
+			goto found;
+		}
+		goto fallback;
+	}
+
+	if (ndirs == 0)
+		ndirs = 1;	/* percpu_counters are approximate... */
+
+	blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;
+
+	max_dirs = ndirs / ngroups + inodes_per_group / 16;
+	min_inodes = avefreei - inodes_per_group / 4;
+	min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;
+
+	max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
+	if (max_debt * INODE_COST > inodes_per_group)
+		max_debt = inodes_per_group / INODE_COST;
+	if (max_debt > 255)
+		max_debt = 255;
+	if (max_debt == 0)
+		max_debt = 1;
+
+	for (i = 0; i < ngroups; i++) {
+		group = (parent_group + i) % ngroups;
+		desc = ext2_get_group_desc (sb, group, NULL);
+		if (!desc || !desc->bg_free_inodes_count)
+			continue;
+		if (sbi->s_debts[group] >= max_debt)
+			continue;
+		if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
+			continue;
+		if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
+			continue;
+		if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
+			continue;
+		goto found;
+	}
+
+fallback:
+	for (i = 0; i < ngroups; i++) {
+		group = (parent_group + i) % ngroups;
+		desc = ext2_get_group_desc (sb, group, NULL);
+		if (!desc || !desc->bg_free_inodes_count)
+			continue;
+		if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
+			goto found;
+	}
+
+	if (avefreei) {
+		/*
+		 * The free-inodes counter is approximate, and for really small
+		 * filesystems the above test can fail to find any blockgroups
+		 */
+		avefreei = 0;
+		goto fallback;
+	}
+
+	return -1;
+
+found:
+	return group;
+}
+
+static int find_group_other(struct super_block *sb, struct inode *parent)
+{
+	int parent_group = EXT2_I(parent)->i_block_group;
+	int ngroups = EXT2_SB(sb)->s_groups_count;
+	struct ext2_group_desc *desc;
+	int group, i;
+
+	/*
+	 * Try to place the inode in its parent directory
+	 */
+	group = parent_group;
+	desc = ext2_get_group_desc (sb, group, NULL);
+	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
+			le16_to_cpu(desc->bg_free_blocks_count))
+		goto found;
+
+	/*
+	 * We're going to place this inode in a different blockgroup from its
+	 * parent.  We want to cause files in a common directory to all land in
+	 * the same blockgroup.  But we want files which are in a different
+	 * directory which shares a blockgroup with our parent to land in a
+	 * different blockgroup.
+	 *
+	 * So add our directory's i_ino into the starting point for the hash.
+	 */
+	group = (group + parent->i_ino) % ngroups;
+
+	/*
+	 * Use a quadratic hash to find a group with a free inode and some
+	 * free blocks.
+	 */
+	for (i = 1; i < ngroups; i <<= 1) {
+		group += i;
+		if (group >= ngroups)
+			group -= ngroups;
+		desc = ext2_get_group_desc (sb, group, NULL);
+		if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
+				le16_to_cpu(desc->bg_free_blocks_count))
+			goto found;
+	}
+
+	/*
+	 * That failed: try linear search for a free inode, even if that group
+	 * has no free blocks.
+	 */
+	group = parent_group;
+	for (i = 0; i < ngroups; i++) {
+		if (++group >= ngroups)
+			group = 0;
+		desc = ext2_get_group_desc (sb, group, NULL);
+		if (desc && le16_to_cpu(desc->bg_free_inodes_count))
+			goto found;
+	}
+
+	return -1;
+
+found:
+	return group;
+}
+
+struct inode *ext2_new_inode(struct inode *dir, int mode,
+			     const struct qstr *qstr)
+{
+	struct super_block *sb;
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *bh2;
+	int group, i;
+	ino_t ino = 0;
+	struct inode * inode;
+	struct ext2_group_desc *gdp;
+	struct ext2_super_block *es;
+	struct ext2_inode_info *ei;
+	struct ext2_sb_info *sbi;
+	int err;
+
+	sb = dir->i_sb;
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	ei = EXT2_I(inode);
+	sbi = EXT2_SB(sb);
+	es = sbi->s_es;
+	if (S_ISDIR(mode)) {
+		if (test_opt(sb, OLDALLOC))
+			group = find_group_dir(sb, dir);
+		else
+			group = find_group_orlov(sb, dir);
+	} else 
+		group = find_group_other(sb, dir);
+
+	if (group == -1) {
+		err = -ENOSPC;
+		goto fail;
+	}
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		gdp = ext2_get_group_desc(sb, group, &bh2);
+		brelse(bitmap_bh);
+		bitmap_bh = read_inode_bitmap(sb, group);
+		if (!bitmap_bh) {
+			err = -EIO;
+			goto fail;
+		}
+		ino = 0;
+
+repeat_in_this_group:
+		ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
+					      EXT2_INODES_PER_GROUP(sb), ino);
+		if (ino >= EXT2_INODES_PER_GROUP(sb)) {
+			/*
+			 * Rare race: find_group_xx() decided that there were
+			 * free inodes in this group, but by the time we tried
+			 * to allocate one, they're all gone.  This can also
+			 * occur because the counters which find_group_orlov()
+			 * uses are approximate.  So just go and search the
+			 * next block group.
+			 */
+			if (++group == sbi->s_groups_count)
+				group = 0;
+			continue;
+		}
+		if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
+						ino, bitmap_bh->b_data)) {
+			/* we lost this inode */
+			if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
+				/* this group is exhausted, try next group */
+				if (++group == sbi->s_groups_count)
+					group = 0;
+				continue;
+			}
+			/* try to find free inode in the same group */
+			goto repeat_in_this_group;
+		}
+		goto got;
+	}
+
+	/*
+	 * Scanned all blockgroups.
+	 */
+	err = -ENOSPC;
+	goto fail;
+got:
+	mark_buffer_dirty(bitmap_bh);
+	if (sb->s_flags & MS_SYNCHRONOUS)
+		sync_dirty_buffer(bitmap_bh);
+	brelse(bitmap_bh);
+
+	ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
+	if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
+		ext2_error (sb, "ext2_new_inode",
+			    "reserved inode or inode > inodes count - "
+			    "block_group = %d,inode=%lu", group,
+			    (unsigned long) ino);
+		err = -EIO;
+		goto fail;
+	}
+
+	percpu_counter_add(&sbi->s_freeinodes_counter, -1);
+	if (S_ISDIR(mode))
+		percpu_counter_inc(&sbi->s_dirs_counter);
+
+	spin_lock(sb_bgl_lock(sbi, group));
+	le16_add_cpu(&gdp->bg_free_inodes_count, -1);
+	if (S_ISDIR(mode)) {
+		if (sbi->s_debts[group] < 255)
+			sbi->s_debts[group]++;
+		le16_add_cpu(&gdp->bg_used_dirs_count, 1);
+	} else {
+		if (sbi->s_debts[group])
+			sbi->s_debts[group]--;
+	}
+	spin_unlock(sb_bgl_lock(sbi, group));
+
+	sb->s_dirt = 1;
+	mark_buffer_dirty(bh2);
+	if (test_opt(sb, GRPID)) {
+		inode->i_mode = mode;
+		inode->i_uid = current_fsuid();
+		inode->i_gid = dir->i_gid;
+	} else
+		inode_init_owner(inode, dir, mode);
+
+	inode->i_ino = ino;
+	inode->i_blocks = 0;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
+	memset(ei->i_data, 0, sizeof(ei->i_data));
+	ei->i_flags =
+		ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
+	ei->i_faddr = 0;
+	ei->i_frag_no = 0;
+	ei->i_frag_size = 0;
+	ei->i_file_acl = 0;
+	ei->i_dir_acl = 0;
+	ei->i_dtime = 0;
+	ei->i_block_alloc_info = NULL;
+	ei->i_block_group = group;
+	ei->i_dir_start_lookup = 0;
+	ei->i_state = EXT2_STATE_NEW;
+	ext2_set_inode_flags(inode);
+	spin_lock(&sbi->s_next_gen_lock);
+	inode->i_generation = sbi->s_next_generation++;
+	spin_unlock(&sbi->s_next_gen_lock);
+	if (insert_inode_locked(inode) < 0) {
+		err = -EINVAL;
+		goto fail_drop;
+	}
+
+	dquot_initialize(inode);
+	err = dquot_alloc_inode(inode);
+	if (err)
+		goto fail_drop;
+
+	err = ext2_init_acl(inode, dir);
+	if (err)
+		goto fail_free_drop;
+
+	err = ext2_init_security(inode, dir, qstr);
+	if (err)
+		goto fail_free_drop;
+
+	mark_inode_dirty(inode);
+	ext2_debug("allocating inode %lu\n", inode->i_ino);
+	ext2_preread_inode(inode);
+	return inode;
+
+fail_free_drop:
+	dquot_free_inode(inode);
+
+fail_drop:
+	dquot_drop(inode);
+	inode->i_flags |= S_NOQUOTA;
+	inode->i_nlink = 0;
+	unlock_new_inode(inode);
+	iput(inode);
+	return ERR_PTR(err);
+
+fail:
+	make_bad_inode(inode);
+	iput(inode);
+	return ERR_PTR(err);
+}
+
+unsigned long ext2_count_free_inodes (struct super_block * sb)
+{
+	struct ext2_group_desc *desc;
+	unsigned long desc_count = 0;
+	int i;	
+
+#ifdef EXT2FS_DEBUG
+	struct ext2_super_block *es;
+	unsigned long bitmap_count = 0;
+	struct buffer_head *bitmap_bh = NULL;
+
+	es = EXT2_SB(sb)->s_es;
+	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
+		unsigned x;
+
+		desc = ext2_get_group_desc (sb, i, NULL);
+		if (!desc)
+			continue;
+		desc_count += le16_to_cpu(desc->bg_free_inodes_count);
+		brelse(bitmap_bh);
+		bitmap_bh = read_inode_bitmap(sb, i);
+		if (!bitmap_bh)
+			continue;
+
+		x = ext2_count_free(bitmap_bh, EXT2_INODES_PER_GROUP(sb) / 8);
+		printk("group %d: stored = %d, counted = %u\n",
+			i, le16_to_cpu(desc->bg_free_inodes_count), x);
+		bitmap_count += x;
+	}
+	brelse(bitmap_bh);
+	printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
+		percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
+		desc_count, bitmap_count);
+	return desc_count;
+#else
+	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
+		desc = ext2_get_group_desc (sb, i, NULL);
+		if (!desc)
+			continue;
+		desc_count += le16_to_cpu(desc->bg_free_inodes_count);
+	}
+	return desc_count;
+#endif
+}
+
+/* Called at mount-time, super-block is locked */
+unsigned long ext2_count_dirs (struct super_block * sb)
+{
+	unsigned long count = 0;
+	int i;
+
+	for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
+		struct ext2_group_desc *gdp = ext2_get_group_desc (sb, i, NULL);
+		if (!gdp)
+			continue;
+		count += le16_to_cpu(gdp->bg_used_dirs_count);
+	}
+	return count;
+}
+
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
new file mode 100644
index 00000000..788e09a0
--- /dev/null
+++ b/fs/ext2/inode.c
@@ -0,0 +1,1552 @@
+/*
+ *  linux/fs/ext2/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Goal-directed block allocation by Stephen Tweedie
+ * 	(sct@dcs.ed.ac.uk), 1993, 1998
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ * 	(jj@sunsite.ms.mff.cuni.cz)
+ *
+ *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
+ */
+
+#include <linux/time.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h>
+#include <linux/mpage.h>
+#include <linux/fiemap.h>
+#include <linux/namei.h>
+#include "ext2.h"
+#include "acl.h"
+#include "xip.h"
+
+MODULE_AUTHOR("Remy Card and others");
+MODULE_DESCRIPTION("Second Extended Filesystem");
+MODULE_LICENSE("GPL");
+
+static int __ext2_write_inode(struct inode *inode, int do_sync);
+
+/*
+ * Test whether an inode is a fast symlink.
+ */
+static inline int ext2_inode_is_fast_symlink(struct inode *inode)
+{
+	int ea_blocks = EXT2_I(inode)->i_file_acl ?
+		(inode->i_sb->s_blocksize >> 9) : 0;
+
+	return (S_ISLNK(inode->i_mode) &&
+		inode->i_blocks - ea_blocks == 0);
+}
+
+static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
+
+static void ext2_write_failed(struct address_space *mapping, loff_t to)
+{
+	struct inode *inode = mapping->host;
+
+	if (to > inode->i_size) {
+		truncate_pagecache(inode, to, inode->i_size);
+		ext2_truncate_blocks(inode, inode->i_size);
+	}
+}
+
+/*
+ * Called at the last iput() if i_nlink is zero.
+ */
+void ext2_evict_inode(struct inode * inode)
+{
+	struct ext2_block_alloc_info *rsv;
+	int want_delete = 0;
+
+	if (!inode->i_nlink && !is_bad_inode(inode)) {
+		want_delete = 1;
+		dquot_initialize(inode);
+	} else {
+		dquot_drop(inode);
+	}
+
+	truncate_inode_pages(&inode->i_data, 0);
+
+	if (want_delete) {
+		/* set dtime */
+		EXT2_I(inode)->i_dtime	= get_seconds();
+		mark_inode_dirty(inode);
+		__ext2_write_inode(inode, inode_needs_sync(inode));
+		/* truncate to 0 */
+		inode->i_size = 0;
+		if (inode->i_blocks)
+			ext2_truncate_blocks(inode, 0);
+	}
+
+	invalidate_inode_buffers(inode);
+	end_writeback(inode);
+
+	ext2_discard_reservation(inode);
+	rsv = EXT2_I(inode)->i_block_alloc_info;
+	EXT2_I(inode)->i_block_alloc_info = NULL;
+	if (unlikely(rsv))
+		kfree(rsv);
+
+	if (want_delete)
+		ext2_free_inode(inode);
+}
+
+typedef struct {
+	__le32	*p;
+	__le32	key;
+	struct buffer_head *bh;
+} Indirect;
+
+static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
+{
+	p->key = *(p->p = v);
+	p->bh = bh;
+}
+
+static inline int verify_chain(Indirect *from, Indirect *to)
+{
+	while (from <= to && from->key == *from->p)
+		from++;
+	return (from > to);
+}
+
+/**
+ *	ext2_block_to_path - parse the block number into array of offsets
+ *	@inode: inode in question (we are only interested in its superblock)
+ *	@i_block: block number to be parsed
+ *	@offsets: array to store the offsets in
+ *      @boundary: set this non-zero if the referred-to block is likely to be
+ *             followed (on disk) by an indirect block.
+ *	To store the locations of file's data ext2 uses a data structure common
+ *	for UNIX filesystems - tree of pointers anchored in the inode, with
+ *	data blocks at leaves and indirect blocks in intermediate nodes.
+ *	This function translates the block number into path in that tree -
+ *	return value is the path length and @offsets[n] is the offset of
+ *	pointer to (n+1)th node in the nth one. If @block is out of range
+ *	(negative or too large) warning is printed and zero returned.
+ *
+ *	Note: function doesn't find node addresses, so no IO is needed. All
+ *	we need to know is the capacity of indirect blocks (taken from the
+ *	inode->i_sb).
+ */
+
+/*
+ * Portability note: the last comparison (check that we fit into triple
+ * indirect block) is spelled differently, because otherwise on an
+ * architecture with 32-bit longs and 8Kb pages we might get into trouble
+ * if our filesystem had 8Kb blocks. We might use long long, but that would
+ * kill us on x86. Oh, well, at least the sign propagation does not matter -
+ * i_block would have to be negative in the very beginning, so we would not
+ * get there at all.
+ */
+
+static int ext2_block_to_path(struct inode *inode,
+			long i_block, int offsets[4], int *boundary)
+{
+	int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
+	int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
+	const long direct_blocks = EXT2_NDIR_BLOCKS,
+		indirect_blocks = ptrs,
+		double_blocks = (1 << (ptrs_bits * 2));
+	int n = 0;
+	int final = 0;
+
+	if (i_block < 0) {
+		ext2_msg(inode->i_sb, KERN_WARNING,
+			"warning: %s: block < 0", __func__);
+	} else if (i_block < direct_blocks) {
+		offsets[n++] = i_block;
+		final = direct_blocks;
+	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
+		offsets[n++] = EXT2_IND_BLOCK;
+		offsets[n++] = i_block;
+		final = ptrs;
+	} else if ((i_block -= indirect_blocks) < double_blocks) {
+		offsets[n++] = EXT2_DIND_BLOCK;
+		offsets[n++] = i_block >> ptrs_bits;
+		offsets[n++] = i_block & (ptrs - 1);
+		final = ptrs;
+	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
+		offsets[n++] = EXT2_TIND_BLOCK;
+		offsets[n++] = i_block >> (ptrs_bits * 2);
+		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
+		offsets[n++] = i_block & (ptrs - 1);
+		final = ptrs;
+	} else {
+		ext2_msg(inode->i_sb, KERN_WARNING,
+			"warning: %s: block is too big", __func__);
+	}
+	if (boundary)
+		*boundary = final - 1 - (i_block & (ptrs - 1));
+
+	return n;
+}
+
+/**
+ *	ext2_get_branch - read the chain of indirect blocks leading to data
+ *	@inode: inode in question
+ *	@depth: depth of the chain (1 - direct pointer, etc.)
+ *	@offsets: offsets of pointers in inode/indirect blocks
+ *	@chain: place to store the result
+ *	@err: here we store the error value
+ *
+ *	Function fills the array of triples <key, p, bh> and returns %NULL
+ *	if everything went OK or the pointer to the last filled triple
+ *	(incomplete one) otherwise. Upon the return chain[i].key contains
+ *	the number of (i+1)-th block in the chain (as it is stored in memory,
+ *	i.e. little-endian 32-bit), chain[i].p contains the address of that
+ *	number (it points into struct inode for i==0 and into the bh->b_data
+ *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
+ *	block for i>0 and NULL for i==0. In other words, it holds the block
+ *	numbers of the chain, addresses they were taken from (and where we can
+ *	verify that chain did not change) and buffer_heads hosting these
+ *	numbers.
+ *
+ *	Function stops when it stumbles upon zero pointer (absent block)
+ *		(pointer to last triple returned, *@err == 0)
+ *	or when it gets an IO error reading an indirect block
+ *		(ditto, *@err == -EIO)
+ *	or when it notices that chain had been changed while it was reading
+ *		(ditto, *@err == -EAGAIN)
+ *	or when it reads all @depth-1 indirect blocks successfully and finds
+ *	the whole chain, all way to the data (returns %NULL, *err == 0).
+ */
+static Indirect *ext2_get_branch(struct inode *inode,
+				 int depth,
+				 int *offsets,
+				 Indirect chain[4],
+				 int *err)
+{
+	struct super_block *sb = inode->i_sb;
+	Indirect *p = chain;
+	struct buffer_head *bh;
+
+	*err = 0;
+	/* i_data is not going away, no lock needed */
+	add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
+	if (!p->key)
+		goto no_block;
+	while (--depth) {
+		bh = sb_bread(sb, le32_to_cpu(p->key));
+		if (!bh)
+			goto failure;
+		read_lock(&EXT2_I(inode)->i_meta_lock);
+		if (!verify_chain(chain, p))
+			goto changed;
+		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
+		read_unlock(&EXT2_I(inode)->i_meta_lock);
+		if (!p->key)
+			goto no_block;
+	}
+	return NULL;
+
+changed:
+	read_unlock(&EXT2_I(inode)->i_meta_lock);
+	brelse(bh);
+	*err = -EAGAIN;
+	goto no_block;
+failure:
+	*err = -EIO;
+no_block:
+	return p;
+}
+
+/**
+ *	ext2_find_near - find a place for allocation with sufficient locality
+ *	@inode: owner
+ *	@ind: descriptor of indirect block.
+ *
+ *	This function returns the preferred place for block allocation.
+ *	It is used when heuristic for sequential allocation fails.
+ *	Rules are:
+ *	  + if there is a block to the left of our position - allocate near it.
+ *	  + if pointer will live in indirect block - allocate near that block.
+ *	  + if pointer will live in inode - allocate in the same cylinder group.
+ *
+ * In the latter case we colour the starting block by the callers PID to
+ * prevent it from clashing with concurrent allocations for a different inode
+ * in the same block group.   The PID is used here so that functionally related
+ * files will be close-by on-disk.
+ *
+ *	Caller must make sure that @ind is valid and will stay that way.
+ */
+
+static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
+{
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
+	__le32 *p;
+	ext2_fsblk_t bg_start;
+	ext2_fsblk_t colour;
+
+	/* Try to find previous block */
+	for (p = ind->p - 1; p >= start; p--)
+		if (*p)
+			return le32_to_cpu(*p);
+
+	/* No such thing, so let's try location of indirect block */
+	if (ind->bh)
+		return ind->bh->b_blocknr;
+
+	/*
+	 * It is going to be referred from inode itself? OK, just put it into
+	 * the same cylinder group then.
+	 */
+	bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
+	colour = (current->pid % 16) *
+			(EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+	return bg_start + colour;
+}
+
+/**
+ *	ext2_find_goal - find a preferred place for allocation.
+ *	@inode: owner
+ *	@block:  block we want
+ *	@partial: pointer to the last triple within a chain
+ *
+ *	Returns preferred place for a block (the goal).
+ */
+
+static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
+					  Indirect *partial)
+{
+	struct ext2_block_alloc_info *block_i;
+
+	block_i = EXT2_I(inode)->i_block_alloc_info;
+
+	/*
+	 * try the heuristic for sequential allocation,
+	 * failing that at least try to get decent locality.
+	 */
+	if (block_i && (block == block_i->last_alloc_logical_block + 1)
+		&& (block_i->last_alloc_physical_block != 0)) {
+		return block_i->last_alloc_physical_block + 1;
+	}
+
+	return ext2_find_near(inode, partial);
+}
+
+/**
+ *	ext2_blks_to_allocate: Look up the block map and count the number
+ *	of direct blocks need to be allocated for the given branch.
+ *
+ * 	@branch: chain of indirect blocks
+ *	@k: number of blocks need for indirect blocks
+ *	@blks: number of data blocks to be mapped.
+ *	@blocks_to_boundary:  the offset in the indirect block
+ *
+ *	return the total number of blocks to be allocate, including the
+ *	direct and indirect blocks.
+ */
+static int
+ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
+		int blocks_to_boundary)
+{
+	unsigned long count = 0;
+
+	/*
+	 * Simple case, [t,d]Indirect block(s) has not allocated yet
+	 * then it's clear blocks on that path have not allocated
+	 */
+	if (k > 0) {
+		/* right now don't hanel cross boundary allocation */
+		if (blks < blocks_to_boundary + 1)
+			count += blks;
+		else
+			count += blocks_to_boundary + 1;
+		return count;
+	}
+
+	count++;
+	while (count < blks && count <= blocks_to_boundary
+		&& le32_to_cpu(*(branch[0].p + count)) == 0) {
+		count++;
+	}
+	return count;
+}
+
+/**
+ *	ext2_alloc_blocks: multiple allocate blocks needed for a branch
+ *	@indirect_blks: the number of blocks need to allocate for indirect
+ *			blocks
+ *
+ *	@new_blocks: on return it will store the new block numbers for
+ *	the indirect blocks(if needed) and the first direct block,
+ *	@blks:	on return it will store the total number of allocated
+ *		direct blocks
+ */
+static int ext2_alloc_blocks(struct inode *inode,
+			ext2_fsblk_t goal, int indirect_blks, int blks,
+			ext2_fsblk_t new_blocks[4], int *err)
+{
+	int target, i;
+	unsigned long count = 0;
+	int index = 0;
+	ext2_fsblk_t current_block = 0;
+	int ret = 0;
+
+	/*
+	 * Here we try to allocate the requested multiple blocks at once,
+	 * on a best-effort basis.
+	 * To build a branch, we should allocate blocks for
+	 * the indirect blocks(if not allocated yet), and at least
+	 * the first direct block of this branch.  That's the
+	 * minimum number of blocks need to allocate(required)
+	 */
+	target = blks + indirect_blks;
+
+	while (1) {
+		count = target;
+		/* allocating blocks for indirect blocks and direct blocks */
+		current_block = ext2_new_blocks(inode,goal,&count,err);
+		if (*err)
+			goto failed_out;
+
+		target -= count;
+		/* allocate blocks for indirect blocks */
+		while (index < indirect_blks && count) {
+			new_blocks[index++] = current_block++;
+			count--;
+		}
+
+		if (count > 0)
+			break;
+	}
+
+	/* save the new block number for the first direct block */
+	new_blocks[index] = current_block;
+
+	/* total number of blocks allocated for direct blocks */
+	ret = count;
+	*err = 0;
+	return ret;
+failed_out:
+	for (i = 0; i <index; i++)
+		ext2_free_blocks(inode, new_blocks[i], 1);
+	if (index)
+		mark_inode_dirty(inode);
+	return ret;
+}
+
+/**
+ *	ext2_alloc_branch - allocate and set up a chain of blocks.
+ *	@inode: owner
+ *	@num: depth of the chain (number of blocks to allocate)
+ *	@offsets: offsets (in the blocks) to store the pointers to next.
+ *	@branch: place to store the chain in.
+ *
+ *	This function allocates @num blocks, zeroes out all but the last one,
+ *	links them into chain and (if we are synchronous) writes them to disk.
+ *	In other words, it prepares a branch that can be spliced onto the
+ *	inode. It stores the information about that chain in the branch[], in
+ *	the same format as ext2_get_branch() would do. We are calling it after
+ *	we had read the existing part of chain and partial points to the last
+ *	triple of that (one with zero ->key). Upon the exit we have the same
+ *	picture as after the successful ext2_get_block(), except that in one
+ *	place chain is disconnected - *branch->p is still zero (we did not
+ *	set the last link), but branch->key contains the number that should
+ *	be placed into *branch->p to fill that gap.
+ *
+ *	If allocation fails we free all blocks we've allocated (and forget
+ *	their buffer_heads) and return the error value the from failed
+ *	ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
+ *	as described above and return 0.
+ */
+
+static int ext2_alloc_branch(struct inode *inode,
+			int indirect_blks, int *blks, ext2_fsblk_t goal,
+			int *offsets, Indirect *branch)
+{
+	int blocksize = inode->i_sb->s_blocksize;
+	int i, n = 0;
+	int err = 0;
+	struct buffer_head *bh;
+	int num;
+	ext2_fsblk_t new_blocks[4];
+	ext2_fsblk_t current_block;
+
+	num = ext2_alloc_blocks(inode, goal, indirect_blks,
+				*blks, new_blocks, &err);
+	if (err)
+		return err;
+
+	branch[0].key = cpu_to_le32(new_blocks[0]);
+	/*
+	 * metadata blocks and data blocks are allocated.
+	 */
+	for (n = 1; n <= indirect_blks;  n++) {
+		/*
+		 * Get buffer_head for parent block, zero it out
+		 * and set the pointer to new one, then send
+		 * parent to disk.
+		 */
+		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
+		branch[n].bh = bh;
+		lock_buffer(bh);
+		memset(bh->b_data, 0, blocksize);
+		branch[n].p = (__le32 *) bh->b_data + offsets[n];
+		branch[n].key = cpu_to_le32(new_blocks[n]);
+		*branch[n].p = branch[n].key;
+		if ( n == indirect_blks) {
+			current_block = new_blocks[n];
+			/*
+			 * End of chain, update the last new metablock of
+			 * the chain to point to the new allocated
+			 * data blocks numbers
+			 */
+			for (i=1; i < num; i++)
+				*(branch[n].p + i) = cpu_to_le32(++current_block);
+		}
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+		mark_buffer_dirty_inode(bh, inode);
+		/* We used to sync bh here if IS_SYNC(inode).
+		 * But we now rely upon generic_write_sync()
+		 * and b_inode_buffers.  But not for directories.
+		 */
+		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
+			sync_dirty_buffer(bh);
+	}
+	*blks = num;
+	return err;
+}
+
+/**
+ * ext2_splice_branch - splice the allocated branch onto inode.
+ * @inode: owner
+ * @block: (logical) number of block we are adding
+ * @where: location of missing link
+ * @num:   number of indirect blocks we are adding
+ * @blks:  number of direct blocks we are adding
+ *
+ * This function fills the missing link and does all housekeeping needed in
+ * inode (->i_blocks, etc.). In case of success we end up with the full
+ * chain to new block and return 0.
+ */
+static void ext2_splice_branch(struct inode *inode,
+			long block, Indirect *where, int num, int blks)
+{
+	int i;
+	struct ext2_block_alloc_info *block_i;
+	ext2_fsblk_t current_block;
+
+	block_i = EXT2_I(inode)->i_block_alloc_info;
+
+	/* XXX LOCKING probably should have i_meta_lock ?*/
+	/* That's it */
+
+	*where->p = where->key;
+
+	/*
+	 * Update the host buffer_head or inode to point to more just allocated
+	 * direct blocks blocks
+	 */
+	if (num == 0 && blks > 1) {
+		current_block = le32_to_cpu(where->key) + 1;
+		for (i = 1; i < blks; i++)
+			*(where->p + i ) = cpu_to_le32(current_block++);
+	}
+
+	/*
+	 * update the most recently allocated logical & physical block
+	 * in i_block_alloc_info, to assist find the proper goal block for next
+	 * allocation
+	 */
+	if (block_i) {
+		block_i->last_alloc_logical_block = block + blks - 1;
+		block_i->last_alloc_physical_block =
+				le32_to_cpu(where[num].key) + blks - 1;
+	}
+
+	/* We are done with atomic stuff, now do the rest of housekeeping */
+
+	/* had we spliced it onto indirect block? */
+	if (where->bh)
+		mark_buffer_dirty_inode(where->bh, inode);
+
+	inode->i_ctime = CURRENT_TIME_SEC;
+	mark_inode_dirty(inode);
+}
+
+/*
+ * Allocation strategy is simple: if we have to allocate something, we will
+ * have to go the whole way to leaf. So let's do it before attaching anything
+ * to tree, set linkage between the newborn blocks, write them if sync is
+ * required, recheck the path, free and repeat if check fails, otherwise
+ * set the last missing link (that will protect us from any truncate-generated
+ * removals - all blocks on the path are immune now) and possibly force the
+ * write on the parent block.
+ * That has a nice additional property: no special recovery from the failed
+ * allocations is needed - we simply release blocks and do not touch anything
+ * reachable from inode.
+ *
+ * `handle' can be NULL if create == 0.
+ *
+ * return > 0, # of blocks mapped or allocated.
+ * return = 0, if plain lookup failed.
+ * return < 0, error case.
+ */
+static int ext2_get_blocks(struct inode *inode,
+			   sector_t iblock, unsigned long maxblocks,
+			   struct buffer_head *bh_result,
+			   int create)
+{
+	int err = -EIO;
+	int offsets[4];
+	Indirect chain[4];
+	Indirect *partial;
+	ext2_fsblk_t goal;
+	int indirect_blks;
+	int blocks_to_boundary = 0;
+	int depth;
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	int count = 0;
+	ext2_fsblk_t first_block = 0;
+
+	depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
+
+	if (depth == 0)
+		return (err);
+
+	partial = ext2_get_branch(inode, depth, offsets, chain, &err);
+	/* Simplest case - block found, no allocation needed */
+	if (!partial) {
+		first_block = le32_to_cpu(chain[depth - 1].key);
+		clear_buffer_new(bh_result); /* What's this do? */
+		count++;
+		/*map more blocks*/
+		while (count < maxblocks && count <= blocks_to_boundary) {
+			ext2_fsblk_t blk;
+
+			if (!verify_chain(chain, chain + depth - 1)) {
+				/*
+				 * Indirect block might be removed by
+				 * truncate while we were reading it.
+				 * Handling of that case: forget what we've
+				 * got now, go to reread.
+				 */
+				err = -EAGAIN;
+				count = 0;
+				break;
+			}
+			blk = le32_to_cpu(*(chain[depth-1].p + count));
+			if (blk == first_block + count)
+				count++;
+			else
+				break;
+		}
+		if (err != -EAGAIN)
+			goto got_it;
+	}
+
+	/* Next simple case - plain lookup or failed read of indirect block */
+	if (!create || err == -EIO)
+		goto cleanup;
+
+	mutex_lock(&ei->truncate_mutex);
+	/*
+	 * If the indirect block is missing while we are reading
+	 * the chain(ext2_get_branch() returns -EAGAIN err), or
+	 * if the chain has been changed after we grab the semaphore,
+	 * (either because another process truncated this branch, or
+	 * another get_block allocated this branch) re-grab the chain to see if
+	 * the request block has been allocated or not.
+	 *
+	 * Since we already block the truncate/other get_block
+	 * at this point, we will have the current copy of the chain when we
+	 * splice the branch into the tree.
+	 */
+	if (err == -EAGAIN || !verify_chain(chain, partial)) {
+		while (partial > chain) {
+			brelse(partial->bh);
+			partial--;
+		}
+		partial = ext2_get_branch(inode, depth, offsets, chain, &err);
+		if (!partial) {
+			count++;
+			mutex_unlock(&ei->truncate_mutex);
+			if (err)
+				goto cleanup;
+			clear_buffer_new(bh_result);
+			goto got_it;
+		}
+	}
+
+	/*
+	 * Okay, we need to do block allocation.  Lazily initialize the block
+	 * allocation info here if necessary
+	*/
+	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
+		ext2_init_block_alloc_info(inode);
+
+	goal = ext2_find_goal(inode, iblock, partial);
+
+	/* the number of blocks need to allocate for [d,t]indirect blocks */
+	indirect_blks = (chain + depth) - partial - 1;
+	/*
+	 * Next look up the indirect map to count the totoal number of
+	 * direct blocks to allocate for this branch.
+	 */
+	count = ext2_blks_to_allocate(partial, indirect_blks,
+					maxblocks, blocks_to_boundary);
+	/*
+	 * XXX ???? Block out ext2_truncate while we alter the tree
+	 */
+	err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
+				offsets + (partial - chain), partial);
+
+	if (err) {
+		mutex_unlock(&ei->truncate_mutex);
+		goto cleanup;
+	}
+
+	if (ext2_use_xip(inode->i_sb)) {
+		/*
+		 * we need to clear the block
+		 */
+		err = ext2_clear_xip_target (inode,
+			le32_to_cpu(chain[depth-1].key));
+		if (err) {
+			mutex_unlock(&ei->truncate_mutex);
+			goto cleanup;
+		}
+	}
+
+	ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
+	mutex_unlock(&ei->truncate_mutex);
+	set_buffer_new(bh_result);
+got_it:
+	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
+	if (count > blocks_to_boundary)
+		set_buffer_boundary(bh_result);
+	err = count;
+	/* Clean up and exit */
+	partial = chain + depth - 1;	/* the whole chain */
+cleanup:
+	while (partial > chain) {
+		brelse(partial->bh);
+		partial--;
+	}
+	return err;
+}
+
+int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
+{
+	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int ret = ext2_get_blocks(inode, iblock, max_blocks,
+			      bh_result, create);
+	if (ret > 0) {
+		bh_result->b_size = (ret << inode->i_blkbits);
+		ret = 0;
+	}
+	return ret;
+
+}
+
+int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		u64 start, u64 len)
+{
+	return generic_block_fiemap(inode, fieinfo, start, len,
+				    ext2_get_block);
+}
+
+static int ext2_writepage(struct page *page, struct writeback_control *wbc)
+{
+	return block_write_full_page(page, ext2_get_block, wbc);
+}
+
+static int ext2_readpage(struct file *file, struct page *page)
+{
+	return mpage_readpage(page, ext2_get_block);
+}
+
+static int
+ext2_readpages(struct file *file, struct address_space *mapping,
+		struct list_head *pages, unsigned nr_pages)
+{
+	return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
+}
+
+static int
+ext2_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
+				ext2_get_block);
+	if (ret < 0)
+		ext2_write_failed(mapping, pos + len);
+	return ret;
+}
+
+static int ext2_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
+{
+	int ret;
+
+	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
+	if (ret < len)
+		ext2_write_failed(mapping, pos + len);
+	return ret;
+}
+
+static int
+ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	int ret;
+
+	ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
+			       ext2_get_block);
+	if (ret < 0)
+		ext2_write_failed(mapping, pos + len);
+	return ret;
+}
+
+static int ext2_nobh_writepage(struct page *page,
+			struct writeback_control *wbc)
+{
+	return nobh_writepage(page, ext2_get_block, wbc);
+}
+
+static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
+{
+	return generic_block_bmap(mapping,block,ext2_get_block);
+}
+
+static ssize_t
+ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
+			loff_t offset, unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct address_space *mapping = file->f_mapping;
+	struct inode *inode = mapping->host;
+	ssize_t ret;
+
+	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev,
+				iov, offset, nr_segs, ext2_get_block, NULL);
+	if (ret < 0 && (rw & WRITE))
+		ext2_write_failed(mapping, offset + iov_length(iov, nr_segs));
+	return ret;
+}
+
+static int
+ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+	return mpage_writepages(mapping, wbc, ext2_get_block);
+}
+
+const struct address_space_operations ext2_aops = {
+	.readpage		= ext2_readpage,
+	.readpages		= ext2_readpages,
+	.writepage		= ext2_writepage,
+	.write_begin		= ext2_write_begin,
+	.write_end		= ext2_write_end,
+	.bmap			= ext2_bmap,
+	.direct_IO		= ext2_direct_IO,
+	.writepages		= ext2_writepages,
+	.migratepage		= buffer_migrate_page,
+	.is_partially_uptodate	= block_is_partially_uptodate,
+	.error_remove_page	= generic_error_remove_page,
+};
+
+const struct address_space_operations ext2_aops_xip = {
+	.bmap			= ext2_bmap,
+	.get_xip_mem		= ext2_get_xip_mem,
+};
+
+const struct address_space_operations ext2_nobh_aops = {
+	.readpage		= ext2_readpage,
+	.readpages		= ext2_readpages,
+	.writepage		= ext2_nobh_writepage,
+	.write_begin		= ext2_nobh_write_begin,
+	.write_end		= nobh_write_end,
+	.bmap			= ext2_bmap,
+	.direct_IO		= ext2_direct_IO,
+	.writepages		= ext2_writepages,
+	.migratepage		= buffer_migrate_page,
+	.error_remove_page	= generic_error_remove_page,
+};
+
+/*
+ * Probably it should be a library function... search for first non-zero word
+ * or memcmp with zero_page, whatever is better for particular architecture.
+ * Linus?
+ */
+static inline int all_zeroes(__le32 *p, __le32 *q)
+{
+	while (p < q)
+		if (*p++)
+			return 0;
+	return 1;
+}
+
+/**
+ *	ext2_find_shared - find the indirect blocks for partial truncation.
+ *	@inode:	  inode in question
+ *	@depth:	  depth of the affected branch
+ *	@offsets: offsets of pointers in that branch (see ext2_block_to_path)
+ *	@chain:	  place to store the pointers to partial indirect blocks
+ *	@top:	  place to the (detached) top of branch
+ *
+ *	This is a helper function used by ext2_truncate().
+ *
+ *	When we do truncate() we may have to clean the ends of several indirect
+ *	blocks but leave the blocks themselves alive. Block is partially
+ *	truncated if some data below the new i_size is referred from it (and
+ *	it is on the path to the first completely truncated data block, indeed).
+ *	We have to free the top of that path along with everything to the right
+ *	of the path. Since no allocation past the truncation point is possible
+ *	until ext2_truncate() finishes, we may safely do the latter, but top
+ *	of branch may require special attention - pageout below the truncation
+ *	point might try to populate it.
+ *
+ *	We atomically detach the top of branch from the tree, store the block
+ *	number of its root in *@top, pointers to buffer_heads of partially
+ *	truncated blocks - in @chain[].bh and pointers to their last elements
+ *	that should not be removed - in @chain[].p. Return value is the pointer
+ *	to last filled element of @chain.
+ *
+ *	The work left to caller to do the actual freeing of subtrees:
+ *		a) free the subtree starting from *@top
+ *		b) free the subtrees whose roots are stored in
+ *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
+ *		c) free the subtrees growing from the inode past the @chain[0].p
+ *			(no partially truncated stuff there).
+ */
+
+static Indirect *ext2_find_shared(struct inode *inode,
+				int depth,
+				int offsets[4],
+				Indirect chain[4],
+				__le32 *top)
+{
+	Indirect *partial, *p;
+	int k, err;
+
+	*top = 0;
+	for (k = depth; k > 1 && !offsets[k-1]; k--)
+		;
+	partial = ext2_get_branch(inode, k, offsets, chain, &err);
+	if (!partial)
+		partial = chain + k-1;
+	/*
+	 * If the branch acquired continuation since we've looked at it -
+	 * fine, it should all survive and (new) top doesn't belong to us.
+	 */
+	write_lock(&EXT2_I(inode)->i_meta_lock);
+	if (!partial->key && *partial->p) {
+		write_unlock(&EXT2_I(inode)->i_meta_lock);
+		goto no_top;
+	}
+	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
+		;
+	/*
+	 * OK, we've found the last block that must survive. The rest of our
+	 * branch should be detached before unlocking. However, if that rest
+	 * of branch is all ours and does not grow immediately from the inode
+	 * it's easier to cheat and just decrement partial->p.
+	 */
+	if (p == chain + k - 1 && p > chain) {
+		p->p--;
+	} else {
+		*top = *p->p;
+		*p->p = 0;
+	}
+	write_unlock(&EXT2_I(inode)->i_meta_lock);
+
+	while(partial > p)
+	{
+		brelse(partial->bh);
+		partial--;
+	}
+no_top:
+	return partial;
+}
+
+/**
+ *	ext2_free_data - free a list of data blocks
+ *	@inode:	inode we are dealing with
+ *	@p:	array of block numbers
+ *	@q:	points immediately past the end of array
+ *
+ *	We are freeing all blocks referred from that array (numbers are
+ *	stored as little-endian 32-bit) and updating @inode->i_blocks
+ *	appropriately.
+ */
+static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
+{
+	unsigned long block_to_free = 0, count = 0;
+	unsigned long nr;
+
+	for ( ; p < q ; p++) {
+		nr = le32_to_cpu(*p);
+		if (nr) {
+			*p = 0;
+			/* accumulate blocks to free if they're contiguous */
+			if (count == 0)
+				goto free_this;
+			else if (block_to_free == nr - count)
+				count++;
+			else {
+				ext2_free_blocks (inode, block_to_free, count);
+				mark_inode_dirty(inode);
+			free_this:
+				block_to_free = nr;
+				count = 1;
+			}
+		}
+	}
+	if (count > 0) {
+		ext2_free_blocks (inode, block_to_free, count);
+		mark_inode_dirty(inode);
+	}
+}
+
+/**
+ *	ext2_free_branches - free an array of branches
+ *	@inode:	inode we are dealing with
+ *	@p:	array of block numbers
+ *	@q:	pointer immediately past the end of array
+ *	@depth:	depth of the branches to free
+ *
+ *	We are freeing all blocks referred from these branches (numbers are
+ *	stored as little-endian 32-bit) and updating @inode->i_blocks
+ *	appropriately.
+ */
+static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
+{
+	struct buffer_head * bh;
+	unsigned long nr;
+
+	if (depth--) {
+		int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
+		for ( ; p < q ; p++) {
+			nr = le32_to_cpu(*p);
+			if (!nr)
+				continue;
+			*p = 0;
+			bh = sb_bread(inode->i_sb, nr);
+			/*
+			 * A read failure? Report error and clear slot
+			 * (should be rare).
+			 */ 
+			if (!bh) {
+				ext2_error(inode->i_sb, "ext2_free_branches",
+					"Read failure, inode=%ld, block=%ld",
+					inode->i_ino, nr);
+				continue;
+			}
+			ext2_free_branches(inode,
+					   (__le32*)bh->b_data,
+					   (__le32*)bh->b_data + addr_per_block,
+					   depth);
+			bforget(bh);
+			ext2_free_blocks(inode, nr, 1);
+			mark_inode_dirty(inode);
+		}
+	} else
+		ext2_free_data(inode, p, q);
+}
+
+static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
+{
+	__le32 *i_data = EXT2_I(inode)->i_data;
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
+	int offsets[4];
+	Indirect chain[4];
+	Indirect *partial;
+	__le32 nr = 0;
+	int n;
+	long iblock;
+	unsigned blocksize;
+	blocksize = inode->i_sb->s_blocksize;
+	iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
+
+	n = ext2_block_to_path(inode, iblock, offsets, NULL);
+	if (n == 0)
+		return;
+
+	/*
+	 * From here we block out all ext2_get_block() callers who want to
+	 * modify the block allocation tree.
+	 */
+	mutex_lock(&ei->truncate_mutex);
+
+	if (n == 1) {
+		ext2_free_data(inode, i_data+offsets[0],
+					i_data + EXT2_NDIR_BLOCKS);
+		goto do_indirects;
+	}
+
+	partial = ext2_find_shared(inode, n, offsets, chain, &nr);
+	/* Kill the top of shared branch (already detached) */
+	if (nr) {
+		if (partial == chain)
+			mark_inode_dirty(inode);
+		else
+			mark_buffer_dirty_inode(partial->bh, inode);
+		ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
+	}
+	/* Clear the ends of indirect blocks on the shared branch */
+	while (partial > chain) {
+		ext2_free_branches(inode,
+				   partial->p + 1,
+				   (__le32*)partial->bh->b_data+addr_per_block,
+				   (chain+n-1) - partial);
+		mark_buffer_dirty_inode(partial->bh, inode);
+		brelse (partial->bh);
+		partial--;
+	}
+do_indirects:
+	/* Kill the remaining (whole) subtrees */
+	switch (offsets[0]) {
+		default:
+			nr = i_data[EXT2_IND_BLOCK];
+			if (nr) {
+				i_data[EXT2_IND_BLOCK] = 0;
+				mark_inode_dirty(inode);
+				ext2_free_branches(inode, &nr, &nr+1, 1);
+			}
+		case EXT2_IND_BLOCK:
+			nr = i_data[EXT2_DIND_BLOCK];
+			if (nr) {
+				i_data[EXT2_DIND_BLOCK] = 0;
+				mark_inode_dirty(inode);
+				ext2_free_branches(inode, &nr, &nr+1, 2);
+			}
+		case EXT2_DIND_BLOCK:
+			nr = i_data[EXT2_TIND_BLOCK];
+			if (nr) {
+				i_data[EXT2_TIND_BLOCK] = 0;
+				mark_inode_dirty(inode);
+				ext2_free_branches(inode, &nr, &nr+1, 3);
+			}
+		case EXT2_TIND_BLOCK:
+			;
+	}
+
+	ext2_discard_reservation(inode);
+
+	mutex_unlock(&ei->truncate_mutex);
+}
+
+static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
+{
+	/*
+	 * XXX: it seems like a bug here that we don't allow
+	 * IS_APPEND inode to have blocks-past-i_size trimmed off.
+	 * review and fix this.
+	 *
+	 * Also would be nice to be able to handle IO errors and such,
+	 * but that's probably too much to ask.
+	 */
+	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+	    S_ISLNK(inode->i_mode)))
+		return;
+	if (ext2_inode_is_fast_symlink(inode))
+		return;
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return;
+	__ext2_truncate_blocks(inode, offset);
+}
+
+static int ext2_setsize(struct inode *inode, loff_t newsize)
+{
+	int error;
+
+	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+	    S_ISLNK(inode->i_mode)))
+		return -EINVAL;
+	if (ext2_inode_is_fast_symlink(inode))
+		return -EINVAL;
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return -EPERM;
+
+	if (mapping_is_xip(inode->i_mapping))
+		error = xip_truncate_page(inode->i_mapping, newsize);
+	else if (test_opt(inode->i_sb, NOBH))
+		error = nobh_truncate_page(inode->i_mapping,
+				newsize, ext2_get_block);
+	else
+		error = block_truncate_page(inode->i_mapping,
+				newsize, ext2_get_block);
+	if (error)
+		return error;
+
+	truncate_setsize(inode, newsize);
+	__ext2_truncate_blocks(inode, newsize);
+
+	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
+	if (inode_needs_sync(inode)) {
+		sync_mapping_buffers(inode->i_mapping);
+		sync_inode_metadata(inode, 1);
+	} else {
+		mark_inode_dirty(inode);
+	}
+
+	return 0;
+}
+
+static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
+					struct buffer_head **p)
+{
+	struct buffer_head * bh;
+	unsigned long block_group;
+	unsigned long block;
+	unsigned long offset;
+	struct ext2_group_desc * gdp;
+
+	*p = NULL;
+	if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
+	    ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
+		goto Einval;
+
+	block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
+	gdp = ext2_get_group_desc(sb, block_group, NULL);
+	if (!gdp)
+		goto Egdp;
+	/*
+	 * Figure out the offset within the block group inode table
+	 */
+	offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
+	block = le32_to_cpu(gdp->bg_inode_table) +
+		(offset >> EXT2_BLOCK_SIZE_BITS(sb));
+	if (!(bh = sb_bread(sb, block)))
+		goto Eio;
+
+	*p = bh;
+	offset &= (EXT2_BLOCK_SIZE(sb) - 1);
+	return (struct ext2_inode *) (bh->b_data + offset);
+
+Einval:
+	ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
+		   (unsigned long) ino);
+	return ERR_PTR(-EINVAL);
+Eio:
+	ext2_error(sb, "ext2_get_inode",
+		   "unable to read inode block - inode=%lu, block=%lu",
+		   (unsigned long) ino, block);
+Egdp:
+	return ERR_PTR(-EIO);
+}
+
+void ext2_set_inode_flags(struct inode *inode)
+{
+	unsigned int flags = EXT2_I(inode)->i_flags;
+
+	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+	if (flags & EXT2_SYNC_FL)
+		inode->i_flags |= S_SYNC;
+	if (flags & EXT2_APPEND_FL)
+		inode->i_flags |= S_APPEND;
+	if (flags & EXT2_IMMUTABLE_FL)
+		inode->i_flags |= S_IMMUTABLE;
+	if (flags & EXT2_NOATIME_FL)
+		inode->i_flags |= S_NOATIME;
+	if (flags & EXT2_DIRSYNC_FL)
+		inode->i_flags |= S_DIRSYNC;
+}
+
+/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
+void ext2_get_inode_flags(struct ext2_inode_info *ei)
+{
+	unsigned int flags = ei->vfs_inode.i_flags;
+
+	ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
+			EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
+	if (flags & S_SYNC)
+		ei->i_flags |= EXT2_SYNC_FL;
+	if (flags & S_APPEND)
+		ei->i_flags |= EXT2_APPEND_FL;
+	if (flags & S_IMMUTABLE)
+		ei->i_flags |= EXT2_IMMUTABLE_FL;
+	if (flags & S_NOATIME)
+		ei->i_flags |= EXT2_NOATIME_FL;
+	if (flags & S_DIRSYNC)
+		ei->i_flags |= EXT2_DIRSYNC_FL;
+}
+
+struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
+{
+	struct ext2_inode_info *ei;
+	struct buffer_head * bh;
+	struct ext2_inode *raw_inode;
+	struct inode *inode;
+	long ret = -EIO;
+	int n;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	ei = EXT2_I(inode);
+	ei->i_block_alloc_info = NULL;
+
+	raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
+	if (IS_ERR(raw_inode)) {
+		ret = PTR_ERR(raw_inode);
+ 		goto bad_inode;
+	}
+
+	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
+	inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
+	inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
+	if (!(test_opt (inode->i_sb, NO_UID32))) {
+		inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
+		inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
+	}
+	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
+	inode->i_size = le32_to_cpu(raw_inode->i_size);
+	inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
+	inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
+	inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
+	inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
+	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
+	/* We now have enough fields to check if the inode was active or not.
+	 * This is needed because nfsd might try to access dead inodes
+	 * the test is that same one that e2fsck uses
+	 * NeilBrown 1999oct15
+	 */
+	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
+		/* this inode is deleted */
+		brelse (bh);
+		ret = -ESTALE;
+		goto bad_inode;
+	}
+	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
+	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
+	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
+	ei->i_frag_no = raw_inode->i_frag;
+	ei->i_frag_size = raw_inode->i_fsize;
+	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
+	ei->i_dir_acl = 0;
+	if (S_ISREG(inode->i_mode))
+		inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
+	else
+		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
+	ei->i_dtime = 0;
+	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+	ei->i_state = 0;
+	ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
+	ei->i_dir_start_lookup = 0;
+
+	/*
+	 * NOTE! The in-memory inode i_data array is in little-endian order
+	 * even on big-endian machines: we do NOT byteswap the block numbers!
+	 */
+	for (n = 0; n < EXT2_N_BLOCKS; n++)
+		ei->i_data[n] = raw_inode->i_block[n];
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &ext2_file_inode_operations;
+		if (ext2_use_xip(inode->i_sb)) {
+			inode->i_mapping->a_ops = &ext2_aops_xip;
+			inode->i_fop = &ext2_xip_file_operations;
+		} else if (test_opt(inode->i_sb, NOBH)) {
+			inode->i_mapping->a_ops = &ext2_nobh_aops;
+			inode->i_fop = &ext2_file_operations;
+		} else {
+			inode->i_mapping->a_ops = &ext2_aops;
+			inode->i_fop = &ext2_file_operations;
+		}
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &ext2_dir_inode_operations;
+		inode->i_fop = &ext2_dir_operations;
+		if (test_opt(inode->i_sb, NOBH))
+			inode->i_mapping->a_ops = &ext2_nobh_aops;
+		else
+			inode->i_mapping->a_ops = &ext2_aops;
+	} else if (S_ISLNK(inode->i_mode)) {
+		if (ext2_inode_is_fast_symlink(inode)) {
+			inode->i_op = &ext2_fast_symlink_inode_operations;
+			nd_terminate_link(ei->i_data, inode->i_size,
+				sizeof(ei->i_data) - 1);
+		} else {
+			inode->i_op = &ext2_symlink_inode_operations;
+			if (test_opt(inode->i_sb, NOBH))
+				inode->i_mapping->a_ops = &ext2_nobh_aops;
+			else
+				inode->i_mapping->a_ops = &ext2_aops;
+		}
+	} else {
+		inode->i_op = &ext2_special_inode_operations;
+		if (raw_inode->i_block[0])
+			init_special_inode(inode, inode->i_mode,
+			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
+		else 
+			init_special_inode(inode, inode->i_mode,
+			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
+	}
+	brelse (bh);
+	ext2_set_inode_flags(inode);
+	unlock_new_inode(inode);
+	return inode;
+	
+bad_inode:
+	iget_failed(inode);
+	return ERR_PTR(ret);
+}
+
+static int __ext2_write_inode(struct inode *inode, int do_sync)
+{
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	struct super_block *sb = inode->i_sb;
+	ino_t ino = inode->i_ino;
+	uid_t uid = inode->i_uid;
+	gid_t gid = inode->i_gid;
+	struct buffer_head * bh;
+	struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
+	int n;
+	int err = 0;
+
+	if (IS_ERR(raw_inode))
+ 		return -EIO;
+
+	/* For fields not not tracking in the in-memory inode,
+	 * initialise them to zero for new inodes. */
+	if (ei->i_state & EXT2_STATE_NEW)
+		memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
+
+	ext2_get_inode_flags(ei);
+	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+	if (!(test_opt(sb, NO_UID32))) {
+		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
+		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
+/*
+ * Fix up interoperability with old kernels. Otherwise, old inodes get
+ * re-used with the upper 16 bits of the uid/gid intact
+ */
+		if (!ei->i_dtime) {
+			raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
+			raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
+		} else {
+			raw_inode->i_uid_high = 0;
+			raw_inode->i_gid_high = 0;
+		}
+	} else {
+		raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
+		raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
+		raw_inode->i_uid_high = 0;
+		raw_inode->i_gid_high = 0;
+	}
+	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
+	raw_inode->i_size = cpu_to_le32(inode->i_size);
+	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
+	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
+	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
+
+	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
+	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
+	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
+	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
+	raw_inode->i_frag = ei->i_frag_no;
+	raw_inode->i_fsize = ei->i_frag_size;
+	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
+	if (!S_ISREG(inode->i_mode))
+		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
+	else {
+		raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
+		if (inode->i_size > 0x7fffffffULL) {
+			if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
+					EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
+			    EXT2_SB(sb)->s_es->s_rev_level ==
+					cpu_to_le32(EXT2_GOOD_OLD_REV)) {
+			       /* If this is the first large file
+				* created, add a flag to the superblock.
+				*/
+				spin_lock(&EXT2_SB(sb)->s_lock);
+				ext2_update_dynamic_rev(sb);
+				EXT2_SET_RO_COMPAT_FEATURE(sb,
+					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
+				spin_unlock(&EXT2_SB(sb)->s_lock);
+				ext2_write_super(sb);
+			}
+		}
+	}
+	
+	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+		if (old_valid_dev(inode->i_rdev)) {
+			raw_inode->i_block[0] =
+				cpu_to_le32(old_encode_dev(inode->i_rdev));
+			raw_inode->i_block[1] = 0;
+		} else {
+			raw_inode->i_block[0] = 0;
+			raw_inode->i_block[1] =
+				cpu_to_le32(new_encode_dev(inode->i_rdev));
+			raw_inode->i_block[2] = 0;
+		}
+	} else for (n = 0; n < EXT2_N_BLOCKS; n++)
+		raw_inode->i_block[n] = ei->i_data[n];
+	mark_buffer_dirty(bh);
+	if (do_sync) {
+		sync_dirty_buffer(bh);
+		if (buffer_req(bh) && !buffer_uptodate(bh)) {
+			printk ("IO error syncing ext2 inode [%s:%08lx]\n",
+				sb->s_id, (unsigned long) ino);
+			err = -EIO;
+		}
+	}
+	ei->i_state &= ~EXT2_STATE_NEW;
+	brelse (bh);
+	return err;
+}
+
+int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
+}
+
+int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = dentry->d_inode;
+	int error;
+
+	error = inode_change_ok(inode, iattr);
+	if (error)
+		return error;
+
+	if (is_quota_modification(inode, iattr))
+		dquot_initialize(inode);
+	if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
+	    (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
+		error = dquot_transfer(inode, iattr);
+		if (error)
+			return error;
+	}
+	if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
+		error = ext2_setsize(inode, iattr->ia_size);
+		if (error)
+			return error;
+	}
+	setattr_copy(inode, iattr);
+	if (iattr->ia_valid & ATTR_MODE)
+		error = ext2_acl_chmod(inode);
+	mark_inode_dirty(inode);
+
+	return error;
+}
diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
new file mode 100644
index 00000000..f81e250a
--- /dev/null
+++ b/fs/ext2/ioctl.c
@@ -0,0 +1,178 @@
+/*
+ * linux/fs/ext2/ioctl.c
+ *
+ * Copyright (C) 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include "ext2.h"
+#include <linux/capability.h>
+#include <linux/time.h>
+#include <linux/sched.h>
+#include <linux/compat.h>
+#include <linux/mount.h>
+#include <asm/current.h>
+#include <asm/uaccess.h>
+
+
+long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct ext2_inode_info *ei = EXT2_I(inode);
+	unsigned int flags;
+	unsigned short rsv_window_size;
+	int ret;
+
+	ext2_debug ("cmd = %u, arg = %lu\n", cmd, arg);
+
+	switch (cmd) {
+	case EXT2_IOC_GETFLAGS:
+		ext2_get_inode_flags(ei);
+		flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
+		return put_user(flags, (int __user *) arg);
+	case EXT2_IOC_SETFLAGS: {
+		unsigned int oldflags;
+
+		ret = mnt_want_write(filp->f_path.mnt);
+		if (ret)
+			return ret;
+
+		if (!inode_owner_or_capable(inode)) {
+			ret = -EACCES;
+			goto setflags_out;
+		}
+
+		if (get_user(flags, (int __user *) arg)) {
+			ret = -EFAULT;
+			goto setflags_out;
+		}
+
+		flags = ext2_mask_flags(inode->i_mode, flags);
+
+		mutex_lock(&inode->i_mutex);
+		/* Is it quota file? Do not allow user to mess with it */
+		if (IS_NOQUOTA(inode)) {
+			mutex_unlock(&inode->i_mutex);
+			ret = -EPERM;
+			goto setflags_out;
+		}
+		oldflags = ei->i_flags;
+
+		/*
+		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+		 * the relevant capability.
+		 *
+		 * This test looks nicer. Thanks to Pauline Middelink
+		 */
+		if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
+			if (!capable(CAP_LINUX_IMMUTABLE)) {
+				mutex_unlock(&inode->i_mutex);
+				ret = -EPERM;
+				goto setflags_out;
+			}
+		}
+
+		flags = flags & EXT2_FL_USER_MODIFIABLE;
+		flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
+		ei->i_flags = flags;
+		mutex_unlock(&inode->i_mutex);
+
+		ext2_set_inode_flags(inode);
+		inode->i_ctime = CURRENT_TIME_SEC;
+		mark_inode_dirty(inode);
+setflags_out:
+		mnt_drop_write(filp->f_path.mnt);
+		return ret;
+	}
+	case EXT2_IOC_GETVERSION:
+		return put_user(inode->i_generation, (int __user *) arg);
+	case EXT2_IOC_SETVERSION:
+		if (!inode_owner_or_capable(inode))
+			return -EPERM;
+		ret = mnt_want_write(filp->f_path.mnt);
+		if (ret)
+			return ret;
+		if (get_user(inode->i_generation, (int __user *) arg)) {
+			ret = -EFAULT;
+		} else {
+			inode->i_ctime = CURRENT_TIME_SEC;
+			mark_inode_dirty(inode);
+		}
+		mnt_drop_write(filp->f_path.mnt);
+		return ret;
+	case EXT2_IOC_GETRSVSZ:
+		if (test_opt(inode->i_sb, RESERVATION)
+			&& S_ISREG(inode->i_mode)
+			&& ei->i_block_alloc_info) {
+			rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
+			return put_user(rsv_window_size, (int __user *)arg);
+		}
+		return -ENOTTY;
+	case EXT2_IOC_SETRSVSZ: {
+
+		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
+			return -ENOTTY;
+
+		if (!inode_owner_or_capable(inode))
+			return -EACCES;
+
+		if (get_user(rsv_window_size, (int __user *)arg))
+			return -EFAULT;
+
+		ret = mnt_want_write(filp->f_path.mnt);
+		if (ret)
+			return ret;
+
+		if (rsv_window_size > EXT2_MAX_RESERVE_BLOCKS)
+			rsv_window_size = EXT2_MAX_RESERVE_BLOCKS;
+
+		/*
+		 * need to allocate reservation structure for this inode
+		 * before set the window size
+		 */
+		/*
+		 * XXX What lock should protect the rsv_goal_size?
+		 * Accessed in ext2_get_block only.  ext3 uses i_truncate.
+		 */
+		mutex_lock(&ei->truncate_mutex);
+		if (!ei->i_block_alloc_info)
+			ext2_init_block_alloc_info(inode);
+
+		if (ei->i_block_alloc_info){
+			struct ext2_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
+			rsv->rsv_goal_size = rsv_window_size;
+		}
+		mutex_unlock(&ei->truncate_mutex);
+		mnt_drop_write(filp->f_path.mnt);
+		return 0;
+	}
+	default:
+		return -ENOTTY;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+long ext2_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	/* These are just misnamed, they actually get/put from/to user an int */
+	switch (cmd) {
+	case EXT2_IOC32_GETFLAGS:
+		cmd = EXT2_IOC_GETFLAGS;
+		break;
+	case EXT2_IOC32_SETFLAGS:
+		cmd = EXT2_IOC_SETFLAGS;
+		break;
+	case EXT2_IOC32_GETVERSION:
+		cmd = EXT2_IOC_GETVERSION;
+		break;
+	case EXT2_IOC32_SETVERSION:
+		cmd = EXT2_IOC_SETVERSION;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+	return ext2_ioctl(file, cmd, (unsigned long) compat_ptr(arg));
+}
+#endif
diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
new file mode 100644
index 00000000..ed5c5d49
--- /dev/null
+++ b/fs/ext2/namei.c
@@ -0,0 +1,427 @@
+/*
+ * linux/fs/ext2/namei.c
+ *
+ * Rewrite to pagecache. Almost all code had been changed, so blame me
+ * if the things go wrong. Please, send bug reports to
+ * viro@parcelfarce.linux.theplanet.co.uk
+ *
+ * Stuff here is basically a glue between the VFS and generic UNIXish
+ * filesystem that keeps everything in pagecache. All knowledge of the
+ * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
+ * and it's easier to debug that way. In principle we might want to
+ * generalize that a bit and turn it into a library. Or not.
+ *
+ * The only non-static object here is ext2_dir_inode_operations.
+ *
+ * TODO: get rid of kmap() use, add readahead.
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/namei.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "xip.h"
+
+static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
+{
+	int err = ext2_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		unlock_new_inode(inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	unlock_new_inode(inode);
+	iput(inode);
+	return err;
+}
+
+/*
+ * Methods themselves.
+ */
+
+static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
+{
+	struct inode * inode;
+	ino_t ino;
+	
+	if (dentry->d_name.len > EXT2_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	ino = ext2_inode_by_name(dir, &dentry->d_name);
+	inode = NULL;
+	if (ino) {
+		inode = ext2_iget(dir->i_sb, ino);
+		if (IS_ERR(inode)) {
+			if (PTR_ERR(inode) == -ESTALE) {
+				ext2_error(dir->i_sb, __func__,
+						"deleted inode referenced: %lu",
+						(unsigned long) ino);
+				return ERR_PTR(-EIO);
+			} else {
+				return ERR_CAST(inode);
+			}
+		}
+	}
+	return d_splice_alias(inode, dentry);
+}
+
+struct dentry *ext2_get_parent(struct dentry *child)
+{
+	struct qstr dotdot = {.name = "..", .len = 2};
+	unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot);
+	if (!ino)
+		return ERR_PTR(-ENOENT);
+	return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino));
+} 
+
+/*
+ * By the time this is called, we already have created
+ * the directory cache entry for the new file, but it
+ * is so far negative - it has no inode.
+ *
+ * If the create succeeds, we fill in the inode information
+ * with d_instantiate(). 
+ */
+static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
+{
+	struct inode *inode;
+
+	dquot_initialize(dir);
+
+	inode = ext2_new_inode(dir, mode, &dentry->d_name);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	inode->i_op = &ext2_file_inode_operations;
+	if (ext2_use_xip(inode->i_sb)) {
+		inode->i_mapping->a_ops = &ext2_aops_xip;
+		inode->i_fop = &ext2_xip_file_operations;
+	} else if (test_opt(inode->i_sb, NOBH)) {
+		inode->i_mapping->a_ops = &ext2_nobh_aops;
+		inode->i_fop = &ext2_file_operations;
+	} else {
+		inode->i_mapping->a_ops = &ext2_aops;
+		inode->i_fop = &ext2_file_operations;
+	}
+	mark_inode_dirty(inode);
+	return ext2_add_nondir(dentry, inode);
+}
+
+static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev)
+{
+	struct inode * inode;
+	int err;
+
+	if (!new_valid_dev(rdev))
+		return -EINVAL;
+
+	dquot_initialize(dir);
+
+	inode = ext2_new_inode (dir, mode, &dentry->d_name);
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		init_special_inode(inode, inode->i_mode, rdev);
+#ifdef CONFIG_EXT2_FS_XATTR
+		inode->i_op = &ext2_special_inode_operations;
+#endif
+		mark_inode_dirty(inode);
+		err = ext2_add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int ext2_symlink (struct inode * dir, struct dentry * dentry,
+	const char * symname)
+{
+	struct super_block * sb = dir->i_sb;
+	int err = -ENAMETOOLONG;
+	unsigned l = strlen(symname)+1;
+	struct inode * inode;
+
+	if (l > sb->s_blocksize)
+		goto out;
+
+	dquot_initialize(dir);
+
+	inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+
+	if (l > sizeof (EXT2_I(inode)->i_data)) {
+		/* slow symlink */
+		inode->i_op = &ext2_symlink_inode_operations;
+		if (test_opt(inode->i_sb, NOBH))
+			inode->i_mapping->a_ops = &ext2_nobh_aops;
+		else
+			inode->i_mapping->a_ops = &ext2_aops;
+		err = page_symlink(inode, symname, l);
+		if (err)
+			goto out_fail;
+	} else {
+		/* fast symlink */
+		inode->i_op = &ext2_fast_symlink_inode_operations;
+		memcpy((char*)(EXT2_I(inode)->i_data),symname,l);
+		inode->i_size = l-1;
+	}
+	mark_inode_dirty(inode);
+
+	err = ext2_add_nondir(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	unlock_new_inode(inode);
+	iput (inode);
+	goto out;
+}
+
+static int ext2_link (struct dentry * old_dentry, struct inode * dir,
+	struct dentry *dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+	int err;
+
+	if (inode->i_nlink >= EXT2_LINK_MAX)
+		return -EMLINK;
+
+	dquot_initialize(dir);
+
+	inode->i_ctime = CURRENT_TIME_SEC;
+	inode_inc_link_count(inode);
+	ihold(inode);
+
+	err = ext2_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	iput(inode);
+	return err;
+}
+
+static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode)
+{
+	struct inode * inode;
+	int err = -EMLINK;
+
+	if (dir->i_nlink >= EXT2_LINK_MAX)
+		goto out;
+
+	dquot_initialize(dir);
+
+	inode_inc_link_count(dir);
+
+	inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_dir;
+
+	inode->i_op = &ext2_dir_inode_operations;
+	inode->i_fop = &ext2_dir_operations;
+	if (test_opt(inode->i_sb, NOBH))
+		inode->i_mapping->a_ops = &ext2_nobh_aops;
+	else
+		inode->i_mapping->a_ops = &ext2_aops;
+
+	inode_inc_link_count(inode);
+
+	err = ext2_make_empty(inode, dir);
+	if (err)
+		goto out_fail;
+
+	err = ext2_add_link(dentry, inode);
+	if (err)
+		goto out_fail;
+
+	d_instantiate(dentry, inode);
+	unlock_new_inode(inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	inode_dec_link_count(inode);
+	unlock_new_inode(inode);
+	iput(inode);
+out_dir:
+	inode_dec_link_count(dir);
+	goto out;
+}
+
+static int ext2_unlink(struct inode * dir, struct dentry *dentry)
+{
+	struct inode * inode = dentry->d_inode;
+	struct ext2_dir_entry_2 * de;
+	struct page * page;
+	int err = -ENOENT;
+
+	dquot_initialize(dir);
+
+	de = ext2_find_entry (dir, &dentry->d_name, &page);
+	if (!de)
+		goto out;
+
+	err = ext2_delete_entry (de, page);
+	if (err)
+		goto out;
+
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+	err = 0;
+out:
+	return err;
+}
+
+static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
+{
+	struct inode * inode = dentry->d_inode;
+	int err = -ENOTEMPTY;
+
+	if (ext2_empty_dir(inode)) {
+		err = ext2_unlink(dir, dentry);
+		if (!err) {
+			inode->i_size = 0;
+			inode_dec_link_count(inode);
+			inode_dec_link_count(dir);
+		}
+	}
+	return err;
+}
+
+static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
+	struct inode * new_dir,	struct dentry * new_dentry )
+{
+	struct inode * old_inode = old_dentry->d_inode;
+	struct inode * new_inode = new_dentry->d_inode;
+	struct page * dir_page = NULL;
+	struct ext2_dir_entry_2 * dir_de = NULL;
+	struct page * old_page;
+	struct ext2_dir_entry_2 * old_de;
+	int err = -ENOENT;
+
+	dquot_initialize(old_dir);
+	dquot_initialize(new_dir);
+
+	old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
+	if (!old_de)
+		goto out;
+
+	if (S_ISDIR(old_inode->i_mode)) {
+		err = -EIO;
+		dir_de = ext2_dotdot(old_inode, &dir_page);
+		if (!dir_de)
+			goto out_old;
+	}
+
+	if (new_inode) {
+		struct page *new_page;
+		struct ext2_dir_entry_2 *new_de;
+
+		err = -ENOTEMPTY;
+		if (dir_de && !ext2_empty_dir (new_inode))
+			goto out_dir;
+
+		err = -ENOENT;
+		new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
+		if (!new_de)
+			goto out_dir;
+		ext2_set_link(new_dir, new_de, new_page, old_inode, 1);
+		new_inode->i_ctime = CURRENT_TIME_SEC;
+		if (dir_de)
+			drop_nlink(new_inode);
+		inode_dec_link_count(new_inode);
+	} else {
+		if (dir_de) {
+			err = -EMLINK;
+			if (new_dir->i_nlink >= EXT2_LINK_MAX)
+				goto out_dir;
+		}
+		err = ext2_add_link(new_dentry, old_inode);
+		if (err)
+			goto out_dir;
+		if (dir_de)
+			inode_inc_link_count(new_dir);
+	}
+
+	/*
+	 * Like most other Unix systems, set the ctime for inodes on a
+ 	 * rename.
+	 */
+	old_inode->i_ctime = CURRENT_TIME_SEC;
+	mark_inode_dirty(old_inode);
+
+	ext2_delete_entry (old_de, old_page);
+
+	if (dir_de) {
+		if (old_dir != new_dir)
+			ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0);
+		else {
+			kunmap(dir_page);
+			page_cache_release(dir_page);
+		}
+		inode_dec_link_count(old_dir);
+	}
+	return 0;
+
+
+out_dir:
+	if (dir_de) {
+		kunmap(dir_page);
+		page_cache_release(dir_page);
+	}
+out_old:
+	kunmap(old_page);
+	page_cache_release(old_page);
+out:
+	return err;
+}
+
+const struct inode_operations ext2_dir_inode_operations = {
+	.create		= ext2_create,
+	.lookup		= ext2_lookup,
+	.link		= ext2_link,
+	.unlink		= ext2_unlink,
+	.symlink	= ext2_symlink,
+	.mkdir		= ext2_mkdir,
+	.rmdir		= ext2_rmdir,
+	.mknod		= ext2_mknod,
+	.rename		= ext2_rename,
+#ifdef CONFIG_EXT2_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext2_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+	.setattr	= ext2_setattr,
+	.check_acl	= ext2_check_acl,
+};
+
+const struct inode_operations ext2_special_inode_operations = {
+#ifdef CONFIG_EXT2_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext2_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+	.setattr	= ext2_setattr,
+	.check_acl	= ext2_check_acl,
+};
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
new file mode 100644
index 00000000..1dd62ed3
--- /dev/null
+++ b/fs/ext2/super.c
@@ -0,0 +1,1525 @@
+/*
+ *  linux/fs/ext2/super.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/parser.h>
+#include <linux/random.h>
+#include <linux/buffer_head.h>
+#include <linux/exportfs.h>
+#include <linux/vfs.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/log2.h>
+#include <linux/quotaops.h>
+#include <asm/uaccess.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+#include "xip.h"
+
+static void ext2_sync_super(struct super_block *sb,
+			    struct ext2_super_block *es, int wait);
+static int ext2_remount (struct super_block * sb, int * flags, char * data);
+static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
+static int ext2_sync_fs(struct super_block *sb, int wait);
+
+void ext2_error(struct super_block *sb, const char *function,
+		const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+
+	if (!(sb->s_flags & MS_RDONLY)) {
+		spin_lock(&sbi->s_lock);
+		sbi->s_mount_state |= EXT2_ERROR_FS;
+		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
+		spin_unlock(&sbi->s_lock);
+		ext2_sync_super(sb, es, 1);
+	}
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
+	       sb->s_id, function, &vaf);
+
+	va_end(args);
+
+	if (test_opt(sb, ERRORS_PANIC))
+		panic("EXT2-fs: panic from previous error\n");
+	if (test_opt(sb, ERRORS_RO)) {
+		ext2_msg(sb, KERN_CRIT,
+			     "error: remounting filesystem read-only");
+		sb->s_flags |= MS_RDONLY;
+	}
+}
+
+void ext2_msg(struct super_block *sb, const char *prefix,
+		const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
+
+	va_end(args);
+}
+
+/*
+ * This must be called with sbi->s_lock held.
+ */
+void ext2_update_dynamic_rev(struct super_block *sb)
+{
+	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
+
+	if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
+		return;
+
+	ext2_msg(sb, KERN_WARNING,
+		     "warning: updating to rev %d because of "
+		     "new feature flag, running e2fsck is recommended",
+		     EXT2_DYNAMIC_REV);
+
+	es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
+	es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
+	es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
+	/* leave es->s_feature_*compat flags alone */
+	/* es->s_uuid will be set by e2fsck if empty */
+
+	/*
+	 * The rest of the superblock fields should be zero, and if not it
+	 * means they are likely already in use, so leave them alone.  We
+	 * can leave it up to e2fsck to clean up any inconsistencies there.
+	 */
+}
+
+static void ext2_put_super (struct super_block * sb)
+{
+	int db_count;
+	int i;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
+
+	if (sb->s_dirt)
+		ext2_write_super(sb);
+
+	ext2_xattr_put_super(sb);
+	if (!(sb->s_flags & MS_RDONLY)) {
+		struct ext2_super_block *es = sbi->s_es;
+
+		spin_lock(&sbi->s_lock);
+		es->s_state = cpu_to_le16(sbi->s_mount_state);
+		spin_unlock(&sbi->s_lock);
+		ext2_sync_super(sb, es, 1);
+	}
+	db_count = sbi->s_gdb_count;
+	for (i = 0; i < db_count; i++)
+		if (sbi->s_group_desc[i])
+			brelse (sbi->s_group_desc[i]);
+	kfree(sbi->s_group_desc);
+	kfree(sbi->s_debts);
+	percpu_counter_destroy(&sbi->s_freeblocks_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+	brelse (sbi->s_sbh);
+	sb->s_fs_info = NULL;
+	kfree(sbi->s_blockgroup_lock);
+	kfree(sbi);
+}
+
+static struct kmem_cache * ext2_inode_cachep;
+
+static struct inode *ext2_alloc_inode(struct super_block *sb)
+{
+	struct ext2_inode_info *ei;
+	ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
+	if (!ei)
+		return NULL;
+	ei->i_block_alloc_info = NULL;
+	ei->vfs_inode.i_version = 1;
+	return &ei->vfs_inode;
+}
+
+static void ext2_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	INIT_LIST_HEAD(&inode->i_dentry);
+	kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
+}
+
+static void ext2_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, ext2_i_callback);
+}
+
+static void init_once(void *foo)
+{
+	struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
+
+	rwlock_init(&ei->i_meta_lock);
+#ifdef CONFIG_EXT2_FS_XATTR
+	init_rwsem(&ei->xattr_sem);
+#endif
+	mutex_init(&ei->truncate_mutex);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int init_inodecache(void)
+{
+	ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
+					     sizeof(struct ext2_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD),
+					     init_once);
+	if (ext2_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	kmem_cache_destroy(ext2_inode_cachep);
+}
+
+static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+	struct super_block *sb = vfs->mnt_sb;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+	unsigned long def_mount_opts;
+
+	spin_lock(&sbi->s_lock);
+	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+
+	if (sbi->s_sb_block != 1)
+		seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
+	if (test_opt(sb, MINIX_DF))
+		seq_puts(seq, ",minixdf");
+	if (test_opt(sb, GRPID))
+		seq_puts(seq, ",grpid");
+	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
+		seq_puts(seq, ",nogrpid");
+	if (sbi->s_resuid != EXT2_DEF_RESUID ||
+	    le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
+		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
+	}
+	if (sbi->s_resgid != EXT2_DEF_RESGID ||
+	    le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
+		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
+	}
+	if (test_opt(sb, ERRORS_RO)) {
+		int def_errors = le16_to_cpu(es->s_errors);
+
+		if (def_errors == EXT2_ERRORS_PANIC ||
+		    def_errors == EXT2_ERRORS_CONTINUE) {
+			seq_puts(seq, ",errors=remount-ro");
+		}
+	}
+	if (test_opt(sb, ERRORS_CONT))
+		seq_puts(seq, ",errors=continue");
+	if (test_opt(sb, ERRORS_PANIC))
+		seq_puts(seq, ",errors=panic");
+	if (test_opt(sb, NO_UID32))
+		seq_puts(seq, ",nouid32");
+	if (test_opt(sb, DEBUG))
+		seq_puts(seq, ",debug");
+	if (test_opt(sb, OLDALLOC))
+		seq_puts(seq, ",oldalloc");
+
+#ifdef CONFIG_EXT2_FS_XATTR
+	if (test_opt(sb, XATTR_USER))
+		seq_puts(seq, ",user_xattr");
+	if (!test_opt(sb, XATTR_USER) &&
+	    (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
+		seq_puts(seq, ",nouser_xattr");
+	}
+#endif
+
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	if (test_opt(sb, POSIX_ACL))
+		seq_puts(seq, ",acl");
+	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
+		seq_puts(seq, ",noacl");
+#endif
+
+	if (test_opt(sb, NOBH))
+		seq_puts(seq, ",nobh");
+
+#if defined(CONFIG_QUOTA)
+	if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
+		seq_puts(seq, ",usrquota");
+
+	if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
+		seq_puts(seq, ",grpquota");
+#endif
+
+#if defined(CONFIG_EXT2_FS_XIP)
+	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
+		seq_puts(seq, ",xip");
+#endif
+
+	if (!test_opt(sb, RESERVATION))
+		seq_puts(seq, ",noreservation");
+
+	spin_unlock(&sbi->s_lock);
+	return 0;
+}
+
+#ifdef CONFIG_QUOTA
+static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
+static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
+#endif
+
+static const struct super_operations ext2_sops = {
+	.alloc_inode	= ext2_alloc_inode,
+	.destroy_inode	= ext2_destroy_inode,
+	.write_inode	= ext2_write_inode,
+	.evict_inode	= ext2_evict_inode,
+	.put_super	= ext2_put_super,
+	.write_super	= ext2_write_super,
+	.sync_fs	= ext2_sync_fs,
+	.statfs		= ext2_statfs,
+	.remount_fs	= ext2_remount,
+	.show_options	= ext2_show_options,
+#ifdef CONFIG_QUOTA
+	.quota_read	= ext2_quota_read,
+	.quota_write	= ext2_quota_write,
+#endif
+};
+
+static struct inode *ext2_nfs_get_inode(struct super_block *sb,
+		u64 ino, u32 generation)
+{
+	struct inode *inode;
+
+	if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
+		return ERR_PTR(-ESTALE);
+	if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
+		return ERR_PTR(-ESTALE);
+
+	/* iget isn't really right if the inode is currently unallocated!!
+	 * ext2_read_inode currently does appropriate checks, but
+	 * it might be "neater" to call ext2_get_inode first and check
+	 * if the inode is valid.....
+	 */
+	inode = ext2_iget(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (generation && inode->i_generation != generation) {
+		/* we didn't find the right inode.. */
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return inode;
+}
+
+static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    ext2_nfs_get_inode);
+}
+
+static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    ext2_nfs_get_inode);
+}
+
+/* Yes, most of these are left as NULL!!
+ * A NULL value implies the default, which works with ext2-like file
+ * systems, but can be improved upon.
+ * Currently only get_parent is required.
+ */
+static const struct export_operations ext2_export_ops = {
+	.fh_to_dentry = ext2_fh_to_dentry,
+	.fh_to_parent = ext2_fh_to_parent,
+	.get_parent = ext2_get_parent,
+};
+
+static unsigned long get_sb_block(void **data)
+{
+	unsigned long 	sb_block;
+	char 		*options = (char *) *data;
+
+	if (!options || strncmp(options, "sb=", 3) != 0)
+		return 1;	/* Default location */
+	options += 3;
+	sb_block = simple_strtoul(options, &options, 0);
+	if (*options && *options != ',') {
+		printk("EXT2-fs: Invalid sb specification: %s\n",
+		       (char *) *data);
+		return 1;
+	}
+	if (*options == ',')
+		options++;
+	*data = (void *) options;
+	return sb_block;
+}
+
+enum {
+	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
+	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
+	Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
+	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
+	Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
+	Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
+};
+
+static const match_table_t tokens = {
+	{Opt_bsd_df, "bsddf"},
+	{Opt_minix_df, "minixdf"},
+	{Opt_grpid, "grpid"},
+	{Opt_grpid, "bsdgroups"},
+	{Opt_nogrpid, "nogrpid"},
+	{Opt_nogrpid, "sysvgroups"},
+	{Opt_resgid, "resgid=%u"},
+	{Opt_resuid, "resuid=%u"},
+	{Opt_sb, "sb=%u"},
+	{Opt_err_cont, "errors=continue"},
+	{Opt_err_panic, "errors=panic"},
+	{Opt_err_ro, "errors=remount-ro"},
+	{Opt_nouid32, "nouid32"},
+	{Opt_nocheck, "check=none"},
+	{Opt_nocheck, "nocheck"},
+	{Opt_debug, "debug"},
+	{Opt_oldalloc, "oldalloc"},
+	{Opt_orlov, "orlov"},
+	{Opt_nobh, "nobh"},
+	{Opt_user_xattr, "user_xattr"},
+	{Opt_nouser_xattr, "nouser_xattr"},
+	{Opt_acl, "acl"},
+	{Opt_noacl, "noacl"},
+	{Opt_xip, "xip"},
+	{Opt_grpquota, "grpquota"},
+	{Opt_ignore, "noquota"},
+	{Opt_quota, "quota"},
+	{Opt_usrquota, "usrquota"},
+	{Opt_reservation, "reservation"},
+	{Opt_noreservation, "noreservation"},
+	{Opt_err, NULL}
+};
+
+static int parse_options(char *options, struct super_block *sb)
+{
+	char *p;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep (&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_bsd_df:
+			clear_opt (sbi->s_mount_opt, MINIX_DF);
+			break;
+		case Opt_minix_df:
+			set_opt (sbi->s_mount_opt, MINIX_DF);
+			break;
+		case Opt_grpid:
+			set_opt (sbi->s_mount_opt, GRPID);
+			break;
+		case Opt_nogrpid:
+			clear_opt (sbi->s_mount_opt, GRPID);
+			break;
+		case Opt_resuid:
+			if (match_int(&args[0], &option))
+				return 0;
+			sbi->s_resuid = option;
+			break;
+		case Opt_resgid:
+			if (match_int(&args[0], &option))
+				return 0;
+			sbi->s_resgid = option;
+			break;
+		case Opt_sb:
+			/* handled by get_sb_block() instead of here */
+			/* *sb_block = match_int(&args[0]); */
+			break;
+		case Opt_err_panic:
+			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt (sbi->s_mount_opt, ERRORS_RO);
+			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			break;
+		case Opt_err_ro:
+			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt (sbi->s_mount_opt, ERRORS_RO);
+			break;
+		case Opt_err_cont:
+			clear_opt (sbi->s_mount_opt, ERRORS_RO);
+			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt (sbi->s_mount_opt, ERRORS_CONT);
+			break;
+		case Opt_nouid32:
+			set_opt (sbi->s_mount_opt, NO_UID32);
+			break;
+		case Opt_nocheck:
+			clear_opt (sbi->s_mount_opt, CHECK);
+			break;
+		case Opt_debug:
+			set_opt (sbi->s_mount_opt, DEBUG);
+			break;
+		case Opt_oldalloc:
+			set_opt (sbi->s_mount_opt, OLDALLOC);
+			break;
+		case Opt_orlov:
+			clear_opt (sbi->s_mount_opt, OLDALLOC);
+			break;
+		case Opt_nobh:
+			set_opt (sbi->s_mount_opt, NOBH);
+			break;
+#ifdef CONFIG_EXT2_FS_XATTR
+		case Opt_user_xattr:
+			set_opt (sbi->s_mount_opt, XATTR_USER);
+			break;
+		case Opt_nouser_xattr:
+			clear_opt (sbi->s_mount_opt, XATTR_USER);
+			break;
+#else
+		case Opt_user_xattr:
+		case Opt_nouser_xattr:
+			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
+				"not supported");
+			break;
+#endif
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+		case Opt_acl:
+			set_opt(sbi->s_mount_opt, POSIX_ACL);
+			break;
+		case Opt_noacl:
+			clear_opt(sbi->s_mount_opt, POSIX_ACL);
+			break;
+#else
+		case Opt_acl:
+		case Opt_noacl:
+			ext2_msg(sb, KERN_INFO,
+				"(no)acl options not supported");
+			break;
+#endif
+		case Opt_xip:
+#ifdef CONFIG_EXT2_FS_XIP
+			set_opt (sbi->s_mount_opt, XIP);
+#else
+			ext2_msg(sb, KERN_INFO, "xip option not supported");
+#endif
+			break;
+
+#if defined(CONFIG_QUOTA)
+		case Opt_quota:
+		case Opt_usrquota:
+			set_opt(sbi->s_mount_opt, USRQUOTA);
+			break;
+
+		case Opt_grpquota:
+			set_opt(sbi->s_mount_opt, GRPQUOTA);
+			break;
+#else
+		case Opt_quota:
+		case Opt_usrquota:
+		case Opt_grpquota:
+			ext2_msg(sb, KERN_INFO,
+				"quota operations not supported");
+			break;
+#endif
+
+		case Opt_reservation:
+			set_opt(sbi->s_mount_opt, RESERVATION);
+			ext2_msg(sb, KERN_INFO, "reservations ON");
+			break;
+		case Opt_noreservation:
+			clear_opt(sbi->s_mount_opt, RESERVATION);
+			ext2_msg(sb, KERN_INFO, "reservations OFF");
+			break;
+		case Opt_ignore:
+			break;
+		default:
+			return 0;
+		}
+	}
+	return 1;
+}
+
+static int ext2_setup_super (struct super_block * sb,
+			      struct ext2_super_block * es,
+			      int read_only)
+{
+	int res = 0;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
+		ext2_msg(sb, KERN_ERR,
+			"error: revision level too high, "
+			"forcing read-only mode");
+		res = MS_RDONLY;
+	}
+	if (read_only)
+		return res;
+	if (!(sbi->s_mount_state & EXT2_VALID_FS))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: mounting unchecked fs, "
+			"running e2fsck is recommended");
+	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: mounting fs with errors, "
+			"running e2fsck is recommended");
+	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
+		 le16_to_cpu(es->s_mnt_count) >=
+		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: maximal mount count reached, "
+			"running e2fsck is recommended");
+	else if (le32_to_cpu(es->s_checkinterval) &&
+		(le32_to_cpu(es->s_lastcheck) +
+			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: checktime reached, "
+			"running e2fsck is recommended");
+	if (!le16_to_cpu(es->s_max_mnt_count))
+		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
+	le16_add_cpu(&es->s_mnt_count, 1);
+	if (test_opt (sb, DEBUG))
+		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
+			"bpg=%lu, ipg=%lu, mo=%04lx]",
+			EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
+			sbi->s_frag_size,
+			sbi->s_groups_count,
+			EXT2_BLOCKS_PER_GROUP(sb),
+			EXT2_INODES_PER_GROUP(sb),
+			sbi->s_mount_opt);
+	return res;
+}
+
+static int ext2_check_descriptors(struct super_block *sb)
+{
+	int i;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	ext2_debug ("Checking group descriptors");
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
+		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
+		ext2_fsblk_t last_block;
+
+		if (i == sbi->s_groups_count - 1)
+			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
+		else
+			last_block = first_block +
+				(EXT2_BLOCKS_PER_GROUP(sb) - 1);
+
+		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
+		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
+		{
+			ext2_error (sb, "ext2_check_descriptors",
+				    "Block bitmap for group %d"
+				    " not in group (block %lu)!",
+				    i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
+			return 0;
+		}
+		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
+		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
+		{
+			ext2_error (sb, "ext2_check_descriptors",
+				    "Inode bitmap for group %d"
+				    " not in group (block %lu)!",
+				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
+			return 0;
+		}
+		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
+		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
+		    last_block)
+		{
+			ext2_error (sb, "ext2_check_descriptors",
+				    "Inode table for group %d"
+				    " not in group (block %lu)!",
+				    i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
+			return 0;
+		}
+	}
+	return 1;
+}
+
+/*
+ * Maximal file size.  There is a direct, and {,double-,triple-}indirect
+ * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
+ * We need to be 1 filesystem block less than the 2^32 sector limit.
+ */
+static loff_t ext2_max_size(int bits)
+{
+	loff_t res = EXT2_NDIR_BLOCKS;
+	int meta_blocks;
+	loff_t upper_limit;
+
+	/* This is calculated to be the largest file size for a
+	 * dense, file such that the total number of
+	 * sectors in the file, including data and all indirect blocks,
+	 * does not exceed 2^32 -1
+	 * __u32 i_blocks representing the total number of
+	 * 512 bytes blocks of the file
+	 */
+	upper_limit = (1LL << 32) - 1;
+
+	/* total blocks in file system block size */
+	upper_limit >>= (bits - 9);
+
+
+	/* indirect blocks */
+	meta_blocks = 1;
+	/* double indirect blocks */
+	meta_blocks += 1 + (1LL << (bits-2));
+	/* tripple indirect blocks */
+	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
+
+	upper_limit -= meta_blocks;
+	upper_limit <<= bits;
+
+	res += 1LL << (bits-2);
+	res += 1LL << (2*(bits-2));
+	res += 1LL << (3*(bits-2));
+	res <<= bits;
+	if (res > upper_limit)
+		res = upper_limit;
+
+	if (res > MAX_LFS_FILESIZE)
+		res = MAX_LFS_FILESIZE;
+
+	return res;
+}
+
+static unsigned long descriptor_loc(struct super_block *sb,
+				    unsigned long logic_sb_block,
+				    int nr)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	unsigned long bg, first_meta_bg;
+	int has_super = 0;
+	
+	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
+
+	if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
+	    nr < first_meta_bg)
+		return (logic_sb_block + nr + 1);
+	bg = sbi->s_desc_per_block * nr;
+	if (ext2_bg_has_super(sb, bg))
+		has_super = 1;
+
+	return ext2_group_first_block_no(sb, bg) + has_super;
+}
+
+static int ext2_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct buffer_head * bh;
+	struct ext2_sb_info * sbi;
+	struct ext2_super_block * es;
+	struct inode *root;
+	unsigned long block;
+	unsigned long sb_block = get_sb_block(&data);
+	unsigned long logic_sb_block;
+	unsigned long offset = 0;
+	unsigned long def_mount_opts;
+	long ret = -EINVAL;
+	int blocksize = BLOCK_SIZE;
+	int db_count;
+	int i, j;
+	__le32 features;
+	int err;
+
+	err = -ENOMEM;
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		goto failed_unlock;
+
+	sbi->s_blockgroup_lock =
+		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
+	if (!sbi->s_blockgroup_lock) {
+		kfree(sbi);
+		goto failed_unlock;
+	}
+	sb->s_fs_info = sbi;
+	sbi->s_sb_block = sb_block;
+
+	spin_lock_init(&sbi->s_lock);
+
+	/*
+	 * See what the current blocksize for the device is, and
+	 * use that as the blocksize.  Otherwise (or if the blocksize
+	 * is smaller than the default) use the default.
+	 * This is important for devices that have a hardware
+	 * sectorsize that is larger than the default.
+	 */
+	blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
+	if (!blocksize) {
+		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
+		goto failed_sbi;
+	}
+
+	/*
+	 * If the superblock doesn't start on a hardware sector boundary,
+	 * calculate the offset.  
+	 */
+	if (blocksize != BLOCK_SIZE) {
+		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
+		offset = (sb_block*BLOCK_SIZE) % blocksize;
+	} else {
+		logic_sb_block = sb_block;
+	}
+
+	if (!(bh = sb_bread(sb, logic_sb_block))) {
+		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
+		goto failed_sbi;
+	}
+	/*
+	 * Note: s_es must be initialized as soon as possible because
+	 *       some ext2 macro-instructions depend on its value
+	 */
+	es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
+	sbi->s_es = es;
+	sb->s_magic = le16_to_cpu(es->s_magic);
+
+	if (sb->s_magic != EXT2_SUPER_MAGIC)
+		goto cantfind_ext2;
+
+	/* Set defaults before we parse the mount options */
+	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+	if (def_mount_opts & EXT2_DEFM_DEBUG)
+		set_opt(sbi->s_mount_opt, DEBUG);
+	if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
+		set_opt(sbi->s_mount_opt, GRPID);
+	if (def_mount_opts & EXT2_DEFM_UID16)
+		set_opt(sbi->s_mount_opt, NO_UID32);
+#ifdef CONFIG_EXT2_FS_XATTR
+	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
+		set_opt(sbi->s_mount_opt, XATTR_USER);
+#endif
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	if (def_mount_opts & EXT2_DEFM_ACL)
+		set_opt(sbi->s_mount_opt, POSIX_ACL);
+#endif
+	
+	if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
+		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
+	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
+		set_opt(sbi->s_mount_opt, ERRORS_CONT);
+	else
+		set_opt(sbi->s_mount_opt, ERRORS_RO);
+
+	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
+	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
+	
+	set_opt(sbi->s_mount_opt, RESERVATION);
+
+	if (!parse_options((char *) data, sb))
+		goto failed_mount;
+
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
+		 MS_POSIXACL : 0);
+
+	ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
+				    EXT2_MOUNT_XIP if not */
+
+	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
+	    (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
+	     EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
+	     EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: feature flags set on rev 0 fs, "
+			"running e2fsck is recommended");
+	/*
+	 * Check feature flags regardless of the revision level, since we
+	 * previously didn't change the revision level when setting the flags,
+	 * so there is a chance incompat flags are set on a rev 0 filesystem.
+	 */
+	features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
+	if (features) {
+		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
+		       "unsupported optional features (%x)",
+			le32_to_cpu(features));
+		goto failed_mount;
+	}
+	if (!(sb->s_flags & MS_RDONLY) &&
+	    (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
+		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
+		       "unsupported optional features (%x)",
+		       le32_to_cpu(features));
+		goto failed_mount;
+	}
+
+	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
+
+	if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
+		if (!silent)
+			ext2_msg(sb, KERN_ERR,
+				"error: unsupported blocksize for xip");
+		goto failed_mount;
+	}
+
+	/* If the blocksize doesn't match, re-read the thing.. */
+	if (sb->s_blocksize != blocksize) {
+		brelse(bh);
+
+		if (!sb_set_blocksize(sb, blocksize)) {
+			ext2_msg(sb, KERN_ERR,
+				"error: bad blocksize %d", blocksize);
+			goto failed_sbi;
+		}
+
+		logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
+		offset = (sb_block*BLOCK_SIZE) % blocksize;
+		bh = sb_bread(sb, logic_sb_block);
+		if(!bh) {
+			ext2_msg(sb, KERN_ERR, "error: couldn't read"
+				"superblock on 2nd try");
+			goto failed_sbi;
+		}
+		es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
+		sbi->s_es = es;
+		if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
+			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
+			goto failed_mount;
+		}
+	}
+
+	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
+
+	if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
+		sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
+		sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
+	} else {
+		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
+		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
+		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
+		    !is_power_of_2(sbi->s_inode_size) ||
+		    (sbi->s_inode_size > blocksize)) {
+			ext2_msg(sb, KERN_ERR,
+				"error: unsupported inode size: %d",
+				sbi->s_inode_size);
+			goto failed_mount;
+		}
+	}
+
+	sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
+				   le32_to_cpu(es->s_log_frag_size);
+	if (sbi->s_frag_size == 0)
+		goto cantfind_ext2;
+	sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
+
+	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
+	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
+	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
+
+	if (EXT2_INODE_SIZE(sb) == 0)
+		goto cantfind_ext2;
+	sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
+	if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
+		goto cantfind_ext2;
+	sbi->s_itb_per_group = sbi->s_inodes_per_group /
+					sbi->s_inodes_per_block;
+	sbi->s_desc_per_block = sb->s_blocksize /
+					sizeof (struct ext2_group_desc);
+	sbi->s_sbh = bh;
+	sbi->s_mount_state = le16_to_cpu(es->s_state);
+	sbi->s_addr_per_block_bits =
+		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
+	sbi->s_desc_per_block_bits =
+		ilog2 (EXT2_DESC_PER_BLOCK(sb));
+
+	if (sb->s_magic != EXT2_SUPER_MAGIC)
+		goto cantfind_ext2;
+
+	if (sb->s_blocksize != bh->b_size) {
+		if (!silent)
+			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
+		goto failed_mount;
+	}
+
+	if (sb->s_blocksize != sbi->s_frag_size) {
+		ext2_msg(sb, KERN_ERR,
+			"error: fragsize %lu != blocksize %lu"
+			"(not supported yet)",
+			sbi->s_frag_size, sb->s_blocksize);
+		goto failed_mount;
+	}
+
+	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #blocks per group too big: %lu",
+			sbi->s_blocks_per_group);
+		goto failed_mount;
+	}
+	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #fragments per group too big: %lu",
+			sbi->s_frags_per_group);
+		goto failed_mount;
+	}
+	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #inodes per group too big: %lu",
+			sbi->s_inodes_per_group);
+		goto failed_mount;
+	}
+
+	if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
+		goto cantfind_ext2;
+ 	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
+ 				le32_to_cpu(es->s_first_data_block) - 1)
+ 					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
+	db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
+		   EXT2_DESC_PER_BLOCK(sb);
+	sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
+	if (sbi->s_group_desc == NULL) {
+		ext2_msg(sb, KERN_ERR, "error: not enough memory");
+		goto failed_mount;
+	}
+	bgl_lock_init(sbi->s_blockgroup_lock);
+	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
+	if (!sbi->s_debts) {
+		ext2_msg(sb, KERN_ERR, "error: not enough memory");
+		goto failed_mount_group_desc;
+	}
+	for (i = 0; i < db_count; i++) {
+		block = descriptor_loc(sb, logic_sb_block, i);
+		sbi->s_group_desc[i] = sb_bread(sb, block);
+		if (!sbi->s_group_desc[i]) {
+			for (j = 0; j < i; j++)
+				brelse (sbi->s_group_desc[j]);
+			ext2_msg(sb, KERN_ERR,
+				"error: unable to read group descriptors");
+			goto failed_mount_group_desc;
+		}
+	}
+	if (!ext2_check_descriptors (sb)) {
+		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
+		goto failed_mount2;
+	}
+	sbi->s_gdb_count = db_count;
+	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
+	spin_lock_init(&sbi->s_next_gen_lock);
+
+	/* per fileystem reservation list head & lock */
+	spin_lock_init(&sbi->s_rsv_window_lock);
+	sbi->s_rsv_window_root = RB_ROOT;
+	/*
+	 * Add a single, static dummy reservation to the start of the
+	 * reservation window list --- it gives us a placeholder for
+	 * append-at-start-of-list which makes the allocation logic
+	 * _much_ simpler.
+	 */
+	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
+	sbi->s_rsv_window_head.rsv_goal_size = 0;
+	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
+
+	err = percpu_counter_init(&sbi->s_freeblocks_counter,
+				ext2_count_free_blocks(sb));
+	if (!err) {
+		err = percpu_counter_init(&sbi->s_freeinodes_counter,
+				ext2_count_free_inodes(sb));
+	}
+	if (!err) {
+		err = percpu_counter_init(&sbi->s_dirs_counter,
+				ext2_count_dirs(sb));
+	}
+	if (err) {
+		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
+		goto failed_mount3;
+	}
+	/*
+	 * set up enough so that it can read an inode
+	 */
+	sb->s_op = &ext2_sops;
+	sb->s_export_op = &ext2_export_ops;
+	sb->s_xattr = ext2_xattr_handlers;
+
+#ifdef CONFIG_QUOTA
+	sb->dq_op = &dquot_operations;
+	sb->s_qcop = &dquot_quotactl_ops;
+#endif
+
+	root = ext2_iget(sb, EXT2_ROOT_INO);
+	if (IS_ERR(root)) {
+		ret = PTR_ERR(root);
+		goto failed_mount3;
+	}
+	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
+		iput(root);
+		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
+		goto failed_mount3;
+	}
+
+	sb->s_root = d_alloc_root(root);
+	if (!sb->s_root) {
+		iput(root);
+		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
+		ret = -ENOMEM;
+		goto failed_mount3;
+	}
+	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: mounting ext3 filesystem as ext2");
+	if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
+		sb->s_flags |= MS_RDONLY;
+	ext2_write_super(sb);
+	return 0;
+
+cantfind_ext2:
+	if (!silent)
+		ext2_msg(sb, KERN_ERR,
+			"error: can't find an ext2 filesystem on dev %s.",
+			sb->s_id);
+	goto failed_mount;
+failed_mount3:
+	percpu_counter_destroy(&sbi->s_freeblocks_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+failed_mount2:
+	for (i = 0; i < db_count; i++)
+		brelse(sbi->s_group_desc[i]);
+failed_mount_group_desc:
+	kfree(sbi->s_group_desc);
+	kfree(sbi->s_debts);
+failed_mount:
+	brelse(bh);
+failed_sbi:
+	sb->s_fs_info = NULL;
+	kfree(sbi->s_blockgroup_lock);
+	kfree(sbi);
+failed_unlock:
+	return ret;
+}
+
+static void ext2_clear_super_error(struct super_block *sb)
+{
+	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
+
+	if (buffer_write_io_error(sbh)) {
+		/*
+		 * Oh, dear.  A previous attempt to write the
+		 * superblock failed.  This could happen because the
+		 * USB device was yanked out.  Or it could happen to
+		 * be a transient write error and maybe the block will
+		 * be remapped.  Nothing we can do but to retry the
+		 * write and hope for the best.
+		 */
+		ext2_msg(sb, KERN_ERR,
+		       "previous I/O error to superblock detected\n");
+		clear_buffer_write_io_error(sbh);
+		set_buffer_uptodate(sbh);
+	}
+}
+
+static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
+			    int wait)
+{
+	ext2_clear_super_error(sb);
+	spin_lock(&EXT2_SB(sb)->s_lock);
+	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
+	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
+	es->s_wtime = cpu_to_le32(get_seconds());
+	/* unlock before we do IO */
+	spin_unlock(&EXT2_SB(sb)->s_lock);
+	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
+	if (wait)
+		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
+	sb->s_dirt = 0;
+}
+
+/*
+ * In the second extended file system, it is not necessary to
+ * write the super block since we use a mapping of the
+ * disk super block in a buffer.
+ *
+ * However, this function is still used to set the fs valid
+ * flags to 0.  We need to set this flag to 0 since the fs
+ * may have been checked while mounted and e2fsck may have
+ * set s_state to EXT2_VALID_FS after some corrections.
+ */
+static int ext2_sync_fs(struct super_block *sb, int wait)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
+
+	spin_lock(&sbi->s_lock);
+	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
+		ext2_debug("setting valid to 0\n");
+		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
+	}
+	spin_unlock(&sbi->s_lock);
+	ext2_sync_super(sb, es, wait);
+	return 0;
+}
+
+
+void ext2_write_super(struct super_block *sb)
+{
+	if (!(sb->s_flags & MS_RDONLY))
+		ext2_sync_fs(sb, 1);
+	else
+		sb->s_dirt = 0;
+}
+
+static int ext2_remount (struct super_block * sb, int * flags, char * data)
+{
+	struct ext2_sb_info * sbi = EXT2_SB(sb);
+	struct ext2_super_block * es;
+	unsigned long old_mount_opt = sbi->s_mount_opt;
+	struct ext2_mount_options old_opts;
+	unsigned long old_sb_flags;
+	int err;
+
+	spin_lock(&sbi->s_lock);
+
+	/* Store the old options */
+	old_sb_flags = sb->s_flags;
+	old_opts.s_mount_opt = sbi->s_mount_opt;
+	old_opts.s_resuid = sbi->s_resuid;
+	old_opts.s_resgid = sbi->s_resgid;
+
+	/*
+	 * Allow the "check" option to be passed as a remount option.
+	 */
+	if (!parse_options(data, sb)) {
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
+	ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
+				    EXT2_MOUNT_XIP if not */
+
+	if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
+		ext2_msg(sb, KERN_WARNING,
+			"warning: unsupported blocksize for xip");
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	es = sbi->s_es;
+	if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
+		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
+			 "xip flag with busy inodes while remounting");
+		sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
+		sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
+	}
+	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
+		spin_unlock(&sbi->s_lock);
+		return 0;
+	}
+	if (*flags & MS_RDONLY) {
+		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
+		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
+			spin_unlock(&sbi->s_lock);
+			return 0;
+		}
+
+		/*
+		 * OK, we are remounting a valid rw partition rdonly, so set
+		 * the rdonly flag and then mark the partition as valid again.
+		 */
+		es->s_state = cpu_to_le16(sbi->s_mount_state);
+		es->s_mtime = cpu_to_le32(get_seconds());
+		spin_unlock(&sbi->s_lock);
+
+		err = dquot_suspend(sb, -1);
+		if (err < 0) {
+			spin_lock(&sbi->s_lock);
+			goto restore_opts;
+		}
+
+		ext2_sync_super(sb, es, 1);
+	} else {
+		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
+					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
+		if (ret) {
+			ext2_msg(sb, KERN_WARNING,
+				"warning: couldn't remount RDWR because of "
+				"unsupported optional features (%x).",
+				le32_to_cpu(ret));
+			err = -EROFS;
+			goto restore_opts;
+		}
+		/*
+		 * Mounting a RDONLY partition read-write, so reread and
+		 * store the current valid flag.  (It may have been changed
+		 * by e2fsck since we originally mounted the partition.)
+		 */
+		sbi->s_mount_state = le16_to_cpu(es->s_state);
+		if (!ext2_setup_super (sb, es, 0))
+			sb->s_flags &= ~MS_RDONLY;
+		spin_unlock(&sbi->s_lock);
+
+		ext2_write_super(sb);
+
+		dquot_resume(sb, -1);
+	}
+
+	return 0;
+restore_opts:
+	sbi->s_mount_opt = old_opts.s_mount_opt;
+	sbi->s_resuid = old_opts.s_resuid;
+	sbi->s_resgid = old_opts.s_resgid;
+	sb->s_flags = old_sb_flags;
+	spin_unlock(&sbi->s_lock);
+	return err;
+}
+
+static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+	u64 fsid;
+
+	spin_lock(&sbi->s_lock);
+
+	if (test_opt (sb, MINIX_DF))
+		sbi->s_overhead_last = 0;
+	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
+		unsigned long i, overhead = 0;
+		smp_rmb();
+
+		/*
+		 * Compute the overhead (FS structures). This is constant
+		 * for a given filesystem unless the number of block groups
+		 * changes so we cache the previous value until it does.
+		 */
+
+		/*
+		 * All of the blocks before first_data_block are
+		 * overhead
+		 */
+		overhead = le32_to_cpu(es->s_first_data_block);
+
+		/*
+		 * Add the overhead attributed to the superblock and
+		 * block group descriptors.  If the sparse superblocks
+		 * feature is turned on, then not all groups have this.
+		 */
+		for (i = 0; i < sbi->s_groups_count; i++)
+			overhead += ext2_bg_has_super(sb, i) +
+				ext2_bg_num_gdb(sb, i);
+
+		/*
+		 * Every block group has an inode bitmap, a block
+		 * bitmap, and an inode table.
+		 */
+		overhead += (sbi->s_groups_count *
+			     (2 + sbi->s_itb_per_group));
+		sbi->s_overhead_last = overhead;
+		smp_wmb();
+		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
+	}
+
+	buf->f_type = EXT2_SUPER_MAGIC;
+	buf->f_bsize = sb->s_blocksize;
+	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
+	buf->f_bfree = ext2_count_free_blocks(sb);
+	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
+	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
+	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
+		buf->f_bavail = 0;
+	buf->f_files = le32_to_cpu(es->s_inodes_count);
+	buf->f_ffree = ext2_count_free_inodes(sb);
+	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
+	buf->f_namelen = EXT2_NAME_LEN;
+	fsid = le64_to_cpup((void *)es->s_uuid) ^
+	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
+	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
+	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
+	spin_unlock(&sbi->s_lock);
+	return 0;
+}
+
+static struct dentry *ext2_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
+}
+
+#ifdef CONFIG_QUOTA
+
+/* Read data from quotafile - avoid pagecache and such because we cannot afford
+ * acquiring the locks... As quota files are never truncated and quota code
+ * itself serializes the operations (and no one else should touch the files)
+ * we don't have to be afraid of races */
+static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
+			       size_t len, loff_t off)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
+	int err = 0;
+	int offset = off & (sb->s_blocksize - 1);
+	int tocopy;
+	size_t toread;
+	struct buffer_head tmp_bh;
+	struct buffer_head *bh;
+	loff_t i_size = i_size_read(inode);
+
+	if (off > i_size)
+		return 0;
+	if (off+len > i_size)
+		len = i_size-off;
+	toread = len;
+	while (toread > 0) {
+		tocopy = sb->s_blocksize - offset < toread ?
+				sb->s_blocksize - offset : toread;
+
+		tmp_bh.b_state = 0;
+		tmp_bh.b_size = sb->s_blocksize;
+		err = ext2_get_block(inode, blk, &tmp_bh, 0);
+		if (err < 0)
+			return err;
+		if (!buffer_mapped(&tmp_bh))	/* A hole? */
+			memset(data, 0, tocopy);
+		else {
+			bh = sb_bread(sb, tmp_bh.b_blocknr);
+			if (!bh)
+				return -EIO;
+			memcpy(data, bh->b_data+offset, tocopy);
+			brelse(bh);
+		}
+		offset = 0;
+		toread -= tocopy;
+		data += tocopy;
+		blk++;
+	}
+	return len;
+}
+
+/* Write to quotafile */
+static ssize_t ext2_quota_write(struct super_block *sb, int type,
+				const char *data, size_t len, loff_t off)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
+	int err = 0;
+	int offset = off & (sb->s_blocksize - 1);
+	int tocopy;
+	size_t towrite = len;
+	struct buffer_head tmp_bh;
+	struct buffer_head *bh;
+
+	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
+	while (towrite > 0) {
+		tocopy = sb->s_blocksize - offset < towrite ?
+				sb->s_blocksize - offset : towrite;
+
+		tmp_bh.b_state = 0;
+		err = ext2_get_block(inode, blk, &tmp_bh, 1);
+		if (err < 0)
+			goto out;
+		if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
+			bh = sb_bread(sb, tmp_bh.b_blocknr);
+		else
+			bh = sb_getblk(sb, tmp_bh.b_blocknr);
+		if (!bh) {
+			err = -EIO;
+			goto out;
+		}
+		lock_buffer(bh);
+		memcpy(bh->b_data+offset, data, tocopy);
+		flush_dcache_page(bh->b_page);
+		set_buffer_uptodate(bh);
+		mark_buffer_dirty(bh);
+		unlock_buffer(bh);
+		brelse(bh);
+		offset = 0;
+		towrite -= tocopy;
+		data += tocopy;
+		blk++;
+	}
+out:
+	if (len == towrite) {
+		mutex_unlock(&inode->i_mutex);
+		return err;
+	}
+	if (inode->i_size < off+len-towrite)
+		i_size_write(inode, off+len-towrite);
+	inode->i_version++;
+	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(inode);
+	mutex_unlock(&inode->i_mutex);
+	return len - towrite;
+}
+
+#endif
+
+static struct file_system_type ext2_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ext2",
+	.mount		= ext2_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init init_ext2_fs(void)
+{
+	int err = init_ext2_xattr();
+	if (err)
+		return err;
+	err = init_inodecache();
+	if (err)
+		goto out1;
+        err = register_filesystem(&ext2_fs_type);
+	if (err)
+		goto out;
+	return 0;
+out:
+	destroy_inodecache();
+out1:
+	exit_ext2_xattr();
+	return err;
+}
+
+static void __exit exit_ext2_fs(void)
+{
+	unregister_filesystem(&ext2_fs_type);
+	destroy_inodecache();
+	exit_ext2_xattr();
+}
+
+module_init(init_ext2_fs)
+module_exit(exit_ext2_fs)
diff --git a/fs/ext2/symlink.c b/fs/ext2/symlink.c
new file mode 100644
index 00000000..565cf817
--- /dev/null
+++ b/fs/ext2/symlink.c
@@ -0,0 +1,54 @@
+/*
+ *  linux/fs/ext2/symlink.c
+ *
+ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/symlink.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext2 symlink handling code
+ */
+
+#include "ext2.h"
+#include "xattr.h"
+#include <linux/namei.h>
+
+static void *ext2_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct ext2_inode_info *ei = EXT2_I(dentry->d_inode);
+	nd_set_link(nd, (char *)ei->i_data);
+	return NULL;
+}
+
+const struct inode_operations ext2_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+	.setattr	= ext2_setattr,
+#ifdef CONFIG_EXT2_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext2_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+};
+ 
+const struct inode_operations ext2_fast_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= ext2_follow_link,
+	.setattr	= ext2_setattr,
+#ifdef CONFIG_EXT2_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext2_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+};
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c
new file mode 100644
index 00000000..52997061
--- /dev/null
+++ b/fs/ext2/xattr.c
@@ -0,0 +1,1031 @@
+/*
+ * linux/fs/ext2/xattr.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de>
+ *
+ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
+ * Extended attributes for symlinks and special files added per
+ *  suggestion of Luka Renko <luka.renko@hermes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
+ *  Red Hat Inc.
+ *
+ */
+
+/*
+ * Extended attributes are stored on disk blocks allocated outside of
+ * any inode. The i_file_acl field is then made to point to this allocated
+ * block. If all extended attributes of an inode are identical, these
+ * inodes may share the same extended attribute block. Such situations
+ * are automatically detected by keeping a cache of recent attribute block
+ * numbers and hashes over the block's contents in memory.
+ *
+ *
+ * Extended attribute block layout:
+ *
+ *   +------------------+
+ *   | header           |
+ *   | entry 1          | |
+ *   | entry 2          | | growing downwards
+ *   | entry 3          | v
+ *   | four null bytes  |
+ *   | . . .            |
+ *   | value 1          | ^
+ *   | value 3          | | growing upwards
+ *   | value 2          | |
+ *   +------------------+
+ *
+ * The block header is followed by multiple entry descriptors. These entry
+ * descriptors are variable in size, and aligned to EXT2_XATTR_PAD
+ * byte boundaries. The entry descriptors are sorted by attribute name,
+ * so that two extended attribute blocks can be compared efficiently.
+ *
+ * Attribute values are aligned to the end of the block, stored in
+ * no specific order. They are also padded to EXT2_XATTR_PAD byte
+ * boundaries. No additional gaps are left between them.
+ *
+ * Locking strategy
+ * ----------------
+ * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem.
+ * EA blocks are only changed if they are exclusive to an inode, so
+ * holding xattr_sem also means that nothing but the EA block's reference
+ * count will change. Multiple writers to an EA block are synchronized
+ * by the bh lock. No more than a single bh lock is held at any time
+ * to avoid deadlocks.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mbcache.h>
+#include <linux/quotaops.h>
+#include <linux/rwsem.h>
+#include <linux/security.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+
+#define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data))
+#define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr))
+#define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#ifdef EXT2_XATTR_DEBUG
+# define ea_idebug(inode, f...) do { \
+		printk(KERN_DEBUG "inode %s:%ld: ", \
+			inode->i_sb->s_id, inode->i_ino); \
+		printk(f); \
+		printk("\n"); \
+	} while (0)
+# define ea_bdebug(bh, f...) do { \
+		char b[BDEVNAME_SIZE]; \
+		printk(KERN_DEBUG "block %s:%lu: ", \
+			bdevname(bh->b_bdev, b), \
+			(unsigned long) bh->b_blocknr); \
+		printk(f); \
+		printk("\n"); \
+	} while (0)
+#else
+# define ea_idebug(f...)
+# define ea_bdebug(f...)
+#endif
+
+static int ext2_xattr_set2(struct inode *, struct buffer_head *,
+			   struct ext2_xattr_header *);
+
+static int ext2_xattr_cache_insert(struct buffer_head *);
+static struct buffer_head *ext2_xattr_cache_find(struct inode *,
+						 struct ext2_xattr_header *);
+static void ext2_xattr_rehash(struct ext2_xattr_header *,
+			      struct ext2_xattr_entry *);
+
+static struct mb_cache *ext2_xattr_cache;
+
+static const struct xattr_handler *ext2_xattr_handler_map[] = {
+	[EXT2_XATTR_INDEX_USER]		     = &ext2_xattr_user_handler,
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	[EXT2_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext2_xattr_acl_access_handler,
+	[EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext2_xattr_acl_default_handler,
+#endif
+	[EXT2_XATTR_INDEX_TRUSTED]	     = &ext2_xattr_trusted_handler,
+#ifdef CONFIG_EXT2_FS_SECURITY
+	[EXT2_XATTR_INDEX_SECURITY]	     = &ext2_xattr_security_handler,
+#endif
+};
+
+const struct xattr_handler *ext2_xattr_handlers[] = {
+	&ext2_xattr_user_handler,
+	&ext2_xattr_trusted_handler,
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	&ext2_xattr_acl_access_handler,
+	&ext2_xattr_acl_default_handler,
+#endif
+#ifdef CONFIG_EXT2_FS_SECURITY
+	&ext2_xattr_security_handler,
+#endif
+	NULL
+};
+
+static inline const struct xattr_handler *
+ext2_xattr_handler(int name_index)
+{
+	const struct xattr_handler *handler = NULL;
+
+	if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map))
+		handler = ext2_xattr_handler_map[name_index];
+	return handler;
+}
+
+/*
+ * ext2_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext2_xattr_get(struct inode *inode, int name_index, const char *name,
+	       void *buffer, size_t buffer_size)
+{
+	struct buffer_head *bh = NULL;
+	struct ext2_xattr_entry *entry;
+	size_t name_len, size;
+	char *end;
+	int error;
+
+	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
+		  name_index, name, buffer, (long)buffer_size);
+
+	if (name == NULL)
+		return -EINVAL;
+	down_read(&EXT2_I(inode)->xattr_sem);
+	error = -ENODATA;
+	if (!EXT2_I(inode)->i_file_acl)
+		goto cleanup;
+	ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
+	bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
+	error = -EIO;
+	if (!bh)
+		goto cleanup;
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
+	end = bh->b_data + bh->b_size;
+	if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
+	    HDR(bh)->h_blocks != cpu_to_le32(1)) {
+bad_block:	ext2_error(inode->i_sb, "ext2_xattr_get",
+			"inode %ld: bad block %d", inode->i_ino,
+			EXT2_I(inode)->i_file_acl);
+		error = -EIO;
+		goto cleanup;
+	}
+	/* find named attribute */
+	name_len = strlen(name);
+
+	error = -ERANGE;
+	if (name_len > 255)
+		goto cleanup;
+	entry = FIRST_ENTRY(bh);
+	while (!IS_LAST_ENTRY(entry)) {
+		struct ext2_xattr_entry *next =
+			EXT2_XATTR_NEXT(entry);
+		if ((char *)next >= end)
+			goto bad_block;
+		if (name_index == entry->e_name_index &&
+		    name_len == entry->e_name_len &&
+		    memcmp(name, entry->e_name, name_len) == 0)
+			goto found;
+		entry = next;
+	}
+	if (ext2_xattr_cache_insert(bh))
+		ea_idebug(inode, "cache insert failed");
+	error = -ENODATA;
+	goto cleanup;
+found:
+	/* check the buffer size */
+	if (entry->e_value_block != 0)
+		goto bad_block;
+	size = le32_to_cpu(entry->e_value_size);
+	if (size > inode->i_sb->s_blocksize ||
+	    le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize)
+		goto bad_block;
+
+	if (ext2_xattr_cache_insert(bh))
+		ea_idebug(inode, "cache insert failed");
+	if (buffer) {
+		error = -ERANGE;
+		if (size > buffer_size)
+			goto cleanup;
+		/* return value of attribute */
+		memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
+			size);
+	}
+	error = size;
+
+cleanup:
+	brelse(bh);
+	up_read(&EXT2_I(inode)->xattr_sem);
+
+	return error;
+}
+
+/*
+ * ext2_xattr_list()
+ *
+ * Copy a list of attribute names into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+static int
+ext2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+	struct inode *inode = dentry->d_inode;
+	struct buffer_head *bh = NULL;
+	struct ext2_xattr_entry *entry;
+	char *end;
+	size_t rest = buffer_size;
+	int error;
+
+	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
+		  buffer, (long)buffer_size);
+
+	down_read(&EXT2_I(inode)->xattr_sem);
+	error = 0;
+	if (!EXT2_I(inode)->i_file_acl)
+		goto cleanup;
+	ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl);
+	bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
+	error = -EIO;
+	if (!bh)
+		goto cleanup;
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount));
+	end = bh->b_data + bh->b_size;
+	if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
+	    HDR(bh)->h_blocks != cpu_to_le32(1)) {
+bad_block:	ext2_error(inode->i_sb, "ext2_xattr_list",
+			"inode %ld: bad block %d", inode->i_ino,
+			EXT2_I(inode)->i_file_acl);
+		error = -EIO;
+		goto cleanup;
+	}
+
+	/* check the on-disk data structure */
+	entry = FIRST_ENTRY(bh);
+	while (!IS_LAST_ENTRY(entry)) {
+		struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry);
+
+		if ((char *)next >= end)
+			goto bad_block;
+		entry = next;
+	}
+	if (ext2_xattr_cache_insert(bh))
+		ea_idebug(inode, "cache insert failed");
+
+	/* list the attribute names */
+	for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry);
+	     entry = EXT2_XATTR_NEXT(entry)) {
+		const struct xattr_handler *handler =
+			ext2_xattr_handler(entry->e_name_index);
+
+		if (handler) {
+			size_t size = handler->list(dentry, buffer, rest,
+						    entry->e_name,
+						    entry->e_name_len,
+						    handler->flags);
+			if (buffer) {
+				if (size > rest) {
+					error = -ERANGE;
+					goto cleanup;
+				}
+				buffer += size;
+			}
+			rest -= size;
+		}
+	}
+	error = buffer_size - rest;  /* total size */
+
+cleanup:
+	brelse(bh);
+	up_read(&EXT2_I(inode)->xattr_sem);
+
+	return error;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * dentry->d_inode->i_mutex: don't care
+ */
+ssize_t
+ext2_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+	return ext2_xattr_list(dentry, buffer, size);
+}
+
+/*
+ * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is
+ * not set, set it.
+ */
+static void ext2_xattr_update_super_block(struct super_block *sb)
+{
+	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR))
+		return;
+
+	spin_lock(&EXT2_SB(sb)->s_lock);
+	EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR);
+	spin_unlock(&EXT2_SB(sb)->s_lock);
+	sb->s_dirt = 1;
+	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
+}
+
+/*
+ * ext2_xattr_set()
+ *
+ * Create, replace or remove an extended attribute for this inode.  Value
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext2_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t value_len, int flags)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *bh = NULL;
+	struct ext2_xattr_header *header = NULL;
+	struct ext2_xattr_entry *here, *last;
+	size_t name_len, free, min_offs = sb->s_blocksize;
+	int not_found = 1, error;
+	char *end;
+	
+	/*
+	 * header -- Points either into bh, or to a temporarily
+	 *           allocated buffer.
+	 * here -- The named entry found, or the place for inserting, within
+	 *         the block pointed to by header.
+	 * last -- Points right after the last named entry within the block
+	 *         pointed to by header.
+	 * min_offs -- The offset of the first value (values are aligned
+	 *             towards the end of the block).
+	 * end -- Points right after the block pointed to by header.
+	 */
+	
+	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
+		  name_index, name, value, (long)value_len);
+
+	if (value == NULL)
+		value_len = 0;
+	if (name == NULL)
+		return -EINVAL;
+	name_len = strlen(name);
+	if (name_len > 255 || value_len > sb->s_blocksize)
+		return -ERANGE;
+	down_write(&EXT2_I(inode)->xattr_sem);
+	if (EXT2_I(inode)->i_file_acl) {
+		/* The inode already has an extended attribute block. */
+		bh = sb_bread(sb, EXT2_I(inode)->i_file_acl);
+		error = -EIO;
+		if (!bh)
+			goto cleanup;
+		ea_bdebug(bh, "b_count=%d, refcount=%d",
+			atomic_read(&(bh->b_count)),
+			le32_to_cpu(HDR(bh)->h_refcount));
+		header = HDR(bh);
+		end = bh->b_data + bh->b_size;
+		if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
+		    header->h_blocks != cpu_to_le32(1)) {
+bad_block:		ext2_error(sb, "ext2_xattr_set",
+				"inode %ld: bad block %d", inode->i_ino, 
+				   EXT2_I(inode)->i_file_acl);
+			error = -EIO;
+			goto cleanup;
+		}
+		/* Find the named attribute. */
+		here = FIRST_ENTRY(bh);
+		while (!IS_LAST_ENTRY(here)) {
+			struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here);
+			if ((char *)next >= end)
+				goto bad_block;
+			if (!here->e_value_block && here->e_value_size) {
+				size_t offs = le16_to_cpu(here->e_value_offs);
+				if (offs < min_offs)
+					min_offs = offs;
+			}
+			not_found = name_index - here->e_name_index;
+			if (!not_found)
+				not_found = name_len - here->e_name_len;
+			if (!not_found)
+				not_found = memcmp(name, here->e_name,name_len);
+			if (not_found <= 0)
+				break;
+			here = next;
+		}
+		last = here;
+		/* We still need to compute min_offs and last. */
+		while (!IS_LAST_ENTRY(last)) {
+			struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last);
+			if ((char *)next >= end)
+				goto bad_block;
+			if (!last->e_value_block && last->e_value_size) {
+				size_t offs = le16_to_cpu(last->e_value_offs);
+				if (offs < min_offs)
+					min_offs = offs;
+			}
+			last = next;
+		}
+
+		/* Check whether we have enough space left. */
+		free = min_offs - ((char*)last - (char*)header) - sizeof(__u32);
+	} else {
+		/* We will use a new extended attribute block. */
+		free = sb->s_blocksize -
+			sizeof(struct ext2_xattr_header) - sizeof(__u32);
+		here = last = NULL;  /* avoid gcc uninitialized warning. */
+	}
+
+	if (not_found) {
+		/* Request to remove a nonexistent attribute? */
+		error = -ENODATA;
+		if (flags & XATTR_REPLACE)
+			goto cleanup;
+		error = 0;
+		if (value == NULL)
+			goto cleanup;
+	} else {
+		/* Request to create an existing attribute? */
+		error = -EEXIST;
+		if (flags & XATTR_CREATE)
+			goto cleanup;
+		if (!here->e_value_block && here->e_value_size) {
+			size_t size = le32_to_cpu(here->e_value_size);
+
+			if (le16_to_cpu(here->e_value_offs) + size > 
+			    sb->s_blocksize || size > sb->s_blocksize)
+				goto bad_block;
+			free += EXT2_XATTR_SIZE(size);
+		}
+		free += EXT2_XATTR_LEN(name_len);
+	}
+	error = -ENOSPC;
+	if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len))
+		goto cleanup;
+
+	/* Here we know that we can set the new attribute. */
+
+	if (header) {
+		struct mb_cache_entry *ce;
+
+		/* assert(header == HDR(bh)); */
+		ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev,
+					bh->b_blocknr);
+		lock_buffer(bh);
+		if (header->h_refcount == cpu_to_le32(1)) {
+			ea_bdebug(bh, "modifying in-place");
+			if (ce)
+				mb_cache_entry_free(ce);
+			/* keep the buffer locked while modifying it. */
+		} else {
+			int offset;
+
+			if (ce)
+				mb_cache_entry_release(ce);
+			unlock_buffer(bh);
+			ea_bdebug(bh, "cloning");
+			header = kmalloc(bh->b_size, GFP_KERNEL);
+			error = -ENOMEM;
+			if (header == NULL)
+				goto cleanup;
+			memcpy(header, HDR(bh), bh->b_size);
+			header->h_refcount = cpu_to_le32(1);
+
+			offset = (char *)here - bh->b_data;
+			here = ENTRY((char *)header + offset);
+			offset = (char *)last - bh->b_data;
+			last = ENTRY((char *)header + offset);
+		}
+	} else {
+		/* Allocate a buffer where we construct the new block. */
+		header = kzalloc(sb->s_blocksize, GFP_KERNEL);
+		error = -ENOMEM;
+		if (header == NULL)
+			goto cleanup;
+		end = (char *)header + sb->s_blocksize;
+		header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC);
+		header->h_blocks = header->h_refcount = cpu_to_le32(1);
+		last = here = ENTRY(header+1);
+	}
+
+	/* Iff we are modifying the block in-place, bh is locked here. */
+
+	if (not_found) {
+		/* Insert the new name. */
+		size_t size = EXT2_XATTR_LEN(name_len);
+		size_t rest = (char *)last - (char *)here;
+		memmove((char *)here + size, here, rest);
+		memset(here, 0, size);
+		here->e_name_index = name_index;
+		here->e_name_len = name_len;
+		memcpy(here->e_name, name, name_len);
+	} else {
+		if (!here->e_value_block && here->e_value_size) {
+			char *first_val = (char *)header + min_offs;
+			size_t offs = le16_to_cpu(here->e_value_offs);
+			char *val = (char *)header + offs;
+			size_t size = EXT2_XATTR_SIZE(
+				le32_to_cpu(here->e_value_size));
+
+			if (size == EXT2_XATTR_SIZE(value_len)) {
+				/* The old and the new value have the same
+				   size. Just replace. */
+				here->e_value_size = cpu_to_le32(value_len);
+				memset(val + size - EXT2_XATTR_PAD, 0,
+				       EXT2_XATTR_PAD); /* Clear pad bytes. */
+				memcpy(val, value, value_len);
+				goto skip_replace;
+			}
+
+			/* Remove the old value. */
+			memmove(first_val + size, first_val, val - first_val);
+			memset(first_val, 0, size);
+			here->e_value_offs = 0;
+			min_offs += size;
+
+			/* Adjust all value offsets. */
+			last = ENTRY(header+1);
+			while (!IS_LAST_ENTRY(last)) {
+				size_t o = le16_to_cpu(last->e_value_offs);
+				if (!last->e_value_block && o < offs)
+					last->e_value_offs =
+						cpu_to_le16(o + size);
+				last = EXT2_XATTR_NEXT(last);
+			}
+		}
+		if (value == NULL) {
+			/* Remove the old name. */
+			size_t size = EXT2_XATTR_LEN(name_len);
+			last = ENTRY((char *)last - size);
+			memmove(here, (char*)here + size,
+				(char*)last - (char*)here);
+			memset(last, 0, size);
+		}
+	}
+
+	if (value != NULL) {
+		/* Insert the new value. */
+		here->e_value_size = cpu_to_le32(value_len);
+		if (value_len) {
+			size_t size = EXT2_XATTR_SIZE(value_len);
+			char *val = (char *)header + min_offs - size;
+			here->e_value_offs =
+				cpu_to_le16((char *)val - (char *)header);
+			memset(val + size - EXT2_XATTR_PAD, 0,
+			       EXT2_XATTR_PAD); /* Clear the pad bytes. */
+			memcpy(val, value, value_len);
+		}
+	}
+
+skip_replace:
+	if (IS_LAST_ENTRY(ENTRY(header+1))) {
+		/* This block is now empty. */
+		if (bh && header == HDR(bh))
+			unlock_buffer(bh);  /* we were modifying in-place. */
+		error = ext2_xattr_set2(inode, bh, NULL);
+	} else {
+		ext2_xattr_rehash(header, here);
+		if (bh && header == HDR(bh))
+			unlock_buffer(bh);  /* we were modifying in-place. */
+		error = ext2_xattr_set2(inode, bh, header);
+	}
+
+cleanup:
+	brelse(bh);
+	if (!(bh && header == HDR(bh)))
+		kfree(header);
+	up_write(&EXT2_I(inode)->xattr_sem);
+
+	return error;
+}
+
+/*
+ * Second half of ext2_xattr_set(): Update the file system.
+ */
+static int
+ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh,
+		struct ext2_xattr_header *header)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *new_bh = NULL;
+	int error;
+
+	if (header) {
+		new_bh = ext2_xattr_cache_find(inode, header);
+		if (new_bh) {
+			/* We found an identical block in the cache. */
+			if (new_bh == old_bh) {
+				ea_bdebug(new_bh, "keeping this block");
+			} else {
+				/* The old block is released after updating
+				   the inode.  */
+				ea_bdebug(new_bh, "reusing block");
+
+				error = dquot_alloc_block(inode, 1);
+				if (error) {
+					unlock_buffer(new_bh);
+					goto cleanup;
+				}
+				le32_add_cpu(&HDR(new_bh)->h_refcount, 1);
+				ea_bdebug(new_bh, "refcount now=%d",
+					le32_to_cpu(HDR(new_bh)->h_refcount));
+			}
+			unlock_buffer(new_bh);
+		} else if (old_bh && header == HDR(old_bh)) {
+			/* Keep this block. No need to lock the block as we
+			   don't need to change the reference count. */
+			new_bh = old_bh;
+			get_bh(new_bh);
+			ext2_xattr_cache_insert(new_bh);
+		} else {
+			/* We need to allocate a new block */
+			ext2_fsblk_t goal = ext2_group_first_block_no(sb,
+						EXT2_I(inode)->i_block_group);
+			int block = ext2_new_block(inode, goal, &error);
+			if (error)
+				goto cleanup;
+			ea_idebug(inode, "creating block %d", block);
+
+			new_bh = sb_getblk(sb, block);
+			if (!new_bh) {
+				ext2_free_blocks(inode, block, 1);
+				mark_inode_dirty(inode);
+				error = -EIO;
+				goto cleanup;
+			}
+			lock_buffer(new_bh);
+			memcpy(new_bh->b_data, header, new_bh->b_size);
+			set_buffer_uptodate(new_bh);
+			unlock_buffer(new_bh);
+			ext2_xattr_cache_insert(new_bh);
+			
+			ext2_xattr_update_super_block(sb);
+		}
+		mark_buffer_dirty(new_bh);
+		if (IS_SYNC(inode)) {
+			sync_dirty_buffer(new_bh);
+			error = -EIO;
+			if (buffer_req(new_bh) && !buffer_uptodate(new_bh))
+				goto cleanup;
+		}
+	}
+
+	/* Update the inode. */
+	EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
+	inode->i_ctime = CURRENT_TIME_SEC;
+	if (IS_SYNC(inode)) {
+		error = sync_inode_metadata(inode, 1);
+		/* In case sync failed due to ENOSPC the inode was actually
+		 * written (only some dirty data were not) so we just proceed
+		 * as if nothing happened and cleanup the unused block */
+		if (error && error != -ENOSPC) {
+			if (new_bh && new_bh != old_bh) {
+				dquot_free_block_nodirty(inode, 1);
+				mark_inode_dirty(inode);
+			}
+			goto cleanup;
+		}
+	} else
+		mark_inode_dirty(inode);
+
+	error = 0;
+	if (old_bh && old_bh != new_bh) {
+		struct mb_cache_entry *ce;
+
+		/*
+		 * If there was an old block and we are no longer using it,
+		 * release the old block.
+		 */
+		ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev,
+					old_bh->b_blocknr);
+		lock_buffer(old_bh);
+		if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) {
+			/* Free the old block. */
+			if (ce)
+				mb_cache_entry_free(ce);
+			ea_bdebug(old_bh, "freeing");
+			ext2_free_blocks(inode, old_bh->b_blocknr, 1);
+			mark_inode_dirty(inode);
+			/* We let our caller release old_bh, so we
+			 * need to duplicate the buffer before. */
+			get_bh(old_bh);
+			bforget(old_bh);
+		} else {
+			/* Decrement the refcount only. */
+			le32_add_cpu(&HDR(old_bh)->h_refcount, -1);
+			if (ce)
+				mb_cache_entry_release(ce);
+			dquot_free_block_nodirty(inode, 1);
+			mark_inode_dirty(inode);
+			mark_buffer_dirty(old_bh);
+			ea_bdebug(old_bh, "refcount now=%d",
+				le32_to_cpu(HDR(old_bh)->h_refcount));
+		}
+		unlock_buffer(old_bh);
+	}
+
+cleanup:
+	brelse(new_bh);
+
+	return error;
+}
+
+/*
+ * ext2_xattr_delete_inode()
+ *
+ * Free extended attribute resources associated with this inode. This
+ * is called immediately before an inode is freed.
+ */
+void
+ext2_xattr_delete_inode(struct inode *inode)
+{
+	struct buffer_head *bh = NULL;
+	struct mb_cache_entry *ce;
+
+	down_write(&EXT2_I(inode)->xattr_sem);
+	if (!EXT2_I(inode)->i_file_acl)
+		goto cleanup;
+	bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl);
+	if (!bh) {
+		ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
+			"inode %ld: block %d read error", inode->i_ino,
+			EXT2_I(inode)->i_file_acl);
+		goto cleanup;
+	}
+	ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count)));
+	if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) ||
+	    HDR(bh)->h_blocks != cpu_to_le32(1)) {
+		ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
+			"inode %ld: bad block %d", inode->i_ino,
+			EXT2_I(inode)->i_file_acl);
+		goto cleanup;
+	}
+	ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr);
+	lock_buffer(bh);
+	if (HDR(bh)->h_refcount == cpu_to_le32(1)) {
+		if (ce)
+			mb_cache_entry_free(ce);
+		ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
+		get_bh(bh);
+		bforget(bh);
+		unlock_buffer(bh);
+	} else {
+		le32_add_cpu(&HDR(bh)->h_refcount, -1);
+		if (ce)
+			mb_cache_entry_release(ce);
+		ea_bdebug(bh, "refcount now=%d",
+			le32_to_cpu(HDR(bh)->h_refcount));
+		unlock_buffer(bh);
+		mark_buffer_dirty(bh);
+		if (IS_SYNC(inode))
+			sync_dirty_buffer(bh);
+		dquot_free_block_nodirty(inode, 1);
+	}
+	EXT2_I(inode)->i_file_acl = 0;
+
+cleanup:
+	brelse(bh);
+	up_write(&EXT2_I(inode)->xattr_sem);
+}
+
+/*
+ * ext2_xattr_put_super()
+ *
+ * This is called when a file system is unmounted.
+ */
+void
+ext2_xattr_put_super(struct super_block *sb)
+{
+	mb_cache_shrink(sb->s_bdev);
+}
+
+
+/*
+ * ext2_xattr_cache_insert()
+ *
+ * Create a new entry in the extended attribute cache, and insert
+ * it unless such an entry is already in the cache.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+static int
+ext2_xattr_cache_insert(struct buffer_head *bh)
+{
+	__u32 hash = le32_to_cpu(HDR(bh)->h_hash);
+	struct mb_cache_entry *ce;
+	int error;
+
+	ce = mb_cache_entry_alloc(ext2_xattr_cache, GFP_NOFS);
+	if (!ce)
+		return -ENOMEM;
+	error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash);
+	if (error) {
+		mb_cache_entry_free(ce);
+		if (error == -EBUSY) {
+			ea_bdebug(bh, "already in cache (%d cache entries)",
+				atomic_read(&ext2_xattr_cache->c_entry_count));
+			error = 0;
+		}
+	} else {
+		ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash,
+			  atomic_read(&ext2_xattr_cache->c_entry_count));
+		mb_cache_entry_release(ce);
+	}
+	return error;
+}
+
+/*
+ * ext2_xattr_cmp()
+ *
+ * Compare two extended attribute blocks for equality.
+ *
+ * Returns 0 if the blocks are equal, 1 if they differ, and
+ * a negative error number on errors.
+ */
+static int
+ext2_xattr_cmp(struct ext2_xattr_header *header1,
+	       struct ext2_xattr_header *header2)
+{
+	struct ext2_xattr_entry *entry1, *entry2;
+
+	entry1 = ENTRY(header1+1);
+	entry2 = ENTRY(header2+1);
+	while (!IS_LAST_ENTRY(entry1)) {
+		if (IS_LAST_ENTRY(entry2))
+			return 1;
+		if (entry1->e_hash != entry2->e_hash ||
+		    entry1->e_name_index != entry2->e_name_index ||
+		    entry1->e_name_len != entry2->e_name_len ||
+		    entry1->e_value_size != entry2->e_value_size ||
+		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
+			return 1;
+		if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
+			return -EIO;
+		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
+			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
+			   le32_to_cpu(entry1->e_value_size)))
+			return 1;
+
+		entry1 = EXT2_XATTR_NEXT(entry1);
+		entry2 = EXT2_XATTR_NEXT(entry2);
+	}
+	if (!IS_LAST_ENTRY(entry2))
+		return 1;
+	return 0;
+}
+
+/*
+ * ext2_xattr_cache_find()
+ *
+ * Find an identical extended attribute block.
+ *
+ * Returns a locked buffer head to the block found, or NULL if such
+ * a block was not found or an error occurred.
+ */
+static struct buffer_head *
+ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header)
+{
+	__u32 hash = le32_to_cpu(header->h_hash);
+	struct mb_cache_entry *ce;
+
+	if (!header->h_hash)
+		return NULL;  /* never share */
+	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
+again:
+	ce = mb_cache_entry_find_first(ext2_xattr_cache, inode->i_sb->s_bdev,
+				       hash);
+	while (ce) {
+		struct buffer_head *bh;
+
+		if (IS_ERR(ce)) {
+			if (PTR_ERR(ce) == -EAGAIN)
+				goto again;
+			break;
+		}
+
+		bh = sb_bread(inode->i_sb, ce->e_block);
+		if (!bh) {
+			ext2_error(inode->i_sb, "ext2_xattr_cache_find",
+				"inode %ld: block %ld read error",
+				inode->i_ino, (unsigned long) ce->e_block);
+		} else {
+			lock_buffer(bh);
+			if (le32_to_cpu(HDR(bh)->h_refcount) >
+				   EXT2_XATTR_REFCOUNT_MAX) {
+				ea_idebug(inode, "block %ld refcount %d>%d",
+					  (unsigned long) ce->e_block,
+					  le32_to_cpu(HDR(bh)->h_refcount),
+					  EXT2_XATTR_REFCOUNT_MAX);
+			} else if (!ext2_xattr_cmp(header, HDR(bh))) {
+				ea_bdebug(bh, "b_count=%d",
+					  atomic_read(&(bh->b_count)));
+				mb_cache_entry_release(ce);
+				return bh;
+			}
+			unlock_buffer(bh);
+			brelse(bh);
+		}
+		ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash);
+	}
+	return NULL;
+}
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * ext2_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header,
+					 struct ext2_xattr_entry *entry)
+{
+	__u32 hash = 0;
+	char *name = entry->e_name;
+	int n;
+
+	for (n=0; n < entry->e_name_len; n++) {
+		hash = (hash << NAME_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+		       *name++;
+	}
+
+	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+		__le32 *value = (__le32 *)((char *)header +
+			le16_to_cpu(entry->e_value_offs));
+		for (n = (le32_to_cpu(entry->e_value_size) +
+		     EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) {
+			hash = (hash << VALUE_HASH_SHIFT) ^
+			       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+			       le32_to_cpu(*value++);
+		}
+	}
+	entry->e_hash = cpu_to_le32(hash);
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * ext2_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void ext2_xattr_rehash(struct ext2_xattr_header *header,
+			      struct ext2_xattr_entry *entry)
+{
+	struct ext2_xattr_entry *here;
+	__u32 hash = 0;
+	
+	ext2_xattr_hash_entry(header, entry);
+	here = ENTRY(header+1);
+	while (!IS_LAST_ENTRY(here)) {
+		if (!here->e_hash) {
+			/* Block is not shared if an entry's hash value == 0 */
+			hash = 0;
+			break;
+		}
+		hash = (hash << BLOCK_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+		       le32_to_cpu(here->e_hash);
+		here = EXT2_XATTR_NEXT(here);
+	}
+	header->h_hash = cpu_to_le32(hash);
+}
+
+#undef BLOCK_HASH_SHIFT
+
+int __init
+init_ext2_xattr(void)
+{
+	ext2_xattr_cache = mb_cache_create("ext2_xattr", 6);
+	if (!ext2_xattr_cache)
+		return -ENOMEM;
+	return 0;
+}
+
+void
+exit_ext2_xattr(void)
+{
+	mb_cache_destroy(ext2_xattr_cache);
+}
diff --git a/fs/ext2/xattr.h b/fs/ext2/xattr.h
new file mode 100644
index 00000000..5e41cccf
--- /dev/null
+++ b/fs/ext2/xattr.h
@@ -0,0 +1,127 @@
+/*
+  File: linux/ext2_xattr.h
+
+  On-disk format of extended attributes for the ext2 filesystem.
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/init.h>
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define EXT2_XATTR_MAGIC		0xEA020000
+
+/* Maximum number of references to one attribute block */
+#define EXT2_XATTR_REFCOUNT_MAX		1024
+
+/* Name indexes */
+#define EXT2_XATTR_INDEX_USER			1
+#define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define EXT2_XATTR_INDEX_TRUSTED		4
+#define	EXT2_XATTR_INDEX_LUSTRE			5
+#define EXT2_XATTR_INDEX_SECURITY	        6
+
+struct ext2_xattr_header {
+	__le32	h_magic;	/* magic number for identification */
+	__le32	h_refcount;	/* reference count */
+	__le32	h_blocks;	/* number of disk blocks used */
+	__le32	h_hash;		/* hash value of all attributes */
+	__u32	h_reserved[4];	/* zero right now */
+};
+
+struct ext2_xattr_entry {
+	__u8	e_name_len;	/* length of name */
+	__u8	e_name_index;	/* attribute name index */
+	__le16	e_value_offs;	/* offset in disk block of value */
+	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
+	__le32	e_value_size;	/* size of attribute value */
+	__le32	e_hash;		/* hash value of name and value */
+	char	e_name[0];	/* attribute name */
+};
+
+#define EXT2_XATTR_PAD_BITS		2
+#define EXT2_XATTR_PAD		(1<<EXT2_XATTR_PAD_BITS)
+#define EXT2_XATTR_ROUND		(EXT2_XATTR_PAD-1)
+#define EXT2_XATTR_LEN(name_len) \
+	(((name_len) + EXT2_XATTR_ROUND + \
+	sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
+#define EXT2_XATTR_NEXT(entry) \
+	( (struct ext2_xattr_entry *)( \
+	  (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
+#define EXT2_XATTR_SIZE(size) \
+	(((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
+
+# ifdef CONFIG_EXT2_FS_XATTR
+
+extern const struct xattr_handler ext2_xattr_user_handler;
+extern const struct xattr_handler ext2_xattr_trusted_handler;
+extern const struct xattr_handler ext2_xattr_acl_access_handler;
+extern const struct xattr_handler ext2_xattr_acl_default_handler;
+extern const struct xattr_handler ext2_xattr_security_handler;
+
+extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
+
+extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
+extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
+
+extern void ext2_xattr_delete_inode(struct inode *);
+extern void ext2_xattr_put_super(struct super_block *);
+
+extern int init_ext2_xattr(void);
+extern void exit_ext2_xattr(void);
+
+extern const struct xattr_handler *ext2_xattr_handlers[];
+
+# else  /* CONFIG_EXT2_FS_XATTR */
+
+static inline int
+ext2_xattr_get(struct inode *inode, int name_index,
+	       const char *name, void *buffer, size_t size)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int
+ext2_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t size, int flags)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void
+ext2_xattr_delete_inode(struct inode *inode)
+{
+}
+
+static inline void
+ext2_xattr_put_super(struct super_block *sb)
+{
+}
+
+static inline int
+init_ext2_xattr(void)
+{
+	return 0;
+}
+
+static inline void
+exit_ext2_xattr(void)
+{
+}
+
+#define ext2_xattr_handlers NULL
+
+# endif  /* CONFIG_EXT2_FS_XATTR */
+
+#ifdef CONFIG_EXT2_FS_SECURITY
+extern int ext2_init_security(struct inode *inode, struct inode *dir,
+			      const struct qstr *qstr);
+#else
+static inline int ext2_init_security(struct inode *inode, struct inode *dir,
+				     const struct qstr *qstr)
+{
+	return 0;
+}
+#endif
diff --git a/fs/ext2/xattr_security.c b/fs/ext2/xattr_security.c
new file mode 100644
index 00000000..5d979b43
--- /dev/null
+++ b/fs/ext2/xattr_security.c
@@ -0,0 +1,76 @@
+/*
+ * linux/fs/ext2/xattr_security.c
+ * Handler for storing security labels as extended attributes.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/ext2_fs.h>
+#include <linux/security.h>
+#include "xattr.h"
+
+static size_t
+ext2_xattr_security_list(struct dentry *dentry, char *list, size_t list_size,
+			 const char *name, size_t name_len, int type)
+{
+	const int prefix_len = XATTR_SECURITY_PREFIX_LEN;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext2_xattr_security_get(struct dentry *dentry, const char *name,
+		       void *buffer, size_t size, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext2_xattr_get(dentry->d_inode, EXT2_XATTR_INDEX_SECURITY, name,
+			      buffer, size);
+}
+
+static int
+ext2_xattr_security_set(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext2_xattr_set(dentry->d_inode, EXT2_XATTR_INDEX_SECURITY, name,
+			      value, size, flags);
+}
+
+int
+ext2_init_security(struct inode *inode, struct inode *dir,
+		   const struct qstr *qstr)
+{
+	int err;
+	size_t len;
+	void *value;
+	char *name;
+
+	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return 0;
+		return err;
+	}
+	err = ext2_xattr_set(inode, EXT2_XATTR_INDEX_SECURITY,
+			     name, value, len, 0);
+	kfree(name);
+	kfree(value);
+	return err;
+}
+
+const struct xattr_handler ext2_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.list	= ext2_xattr_security_list,
+	.get	= ext2_xattr_security_get,
+	.set	= ext2_xattr_security_set,
+};
diff --git a/fs/ext2/xattr_trusted.c b/fs/ext2/xattr_trusted.c
new file mode 100644
index 00000000..667e46a8
--- /dev/null
+++ b/fs/ext2/xattr_trusted.c
@@ -0,0 +1,58 @@
+/*
+ * linux/fs/ext2/xattr_trusted.c
+ * Handler for trusted extended attributes.
+ *
+ * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/ext2_fs.h>
+#include "xattr.h"
+
+static size_t
+ext2_xattr_trusted_list(struct dentry *dentry, char *list, size_t list_size,
+		const char *name, size_t name_len, int type)
+{
+	const int prefix_len = XATTR_TRUSTED_PREFIX_LEN;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return 0;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext2_xattr_trusted_get(struct dentry *dentry, const char *name,
+		void *buffer, size_t size, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext2_xattr_get(dentry->d_inode, EXT2_XATTR_INDEX_TRUSTED, name,
+			      buffer, size);
+}
+
+static int
+ext2_xattr_trusted_set(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext2_xattr_set(dentry->d_inode, EXT2_XATTR_INDEX_TRUSTED, name,
+			      value, size, flags);
+}
+
+const struct xattr_handler ext2_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.list	= ext2_xattr_trusted_list,
+	.get	= ext2_xattr_trusted_get,
+	.set	= ext2_xattr_trusted_set,
+};
diff --git a/fs/ext2/xattr_user.c b/fs/ext2/xattr_user.c
new file mode 100644
index 00000000..099d20f4
--- /dev/null
+++ b/fs/ext2/xattr_user.c
@@ -0,0 +1,62 @@
+/*
+ * linux/fs/ext2/xattr_user.c
+ * Handler for extended user attributes.
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include "ext2.h"
+#include "xattr.h"
+
+static size_t
+ext2_xattr_user_list(struct dentry *dentry, char *list, size_t list_size,
+		const char *name, size_t name_len, int type)
+{
+	const size_t prefix_len = XATTR_USER_PREFIX_LEN;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (!test_opt(dentry->d_sb, XATTR_USER))
+		return 0;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_USER_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext2_xattr_user_get(struct dentry *dentry, const char *name,
+		void *buffer, size_t size, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	if (!test_opt(dentry->d_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext2_xattr_get(dentry->d_inode, EXT2_XATTR_INDEX_USER,
+			      name, buffer, size);
+}
+
+static int
+ext2_xattr_user_set(struct dentry *dentry, const char *name,
+		const void *value, size_t size, int flags, int type)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	if (!test_opt(dentry->d_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+
+	return ext2_xattr_set(dentry->d_inode, EXT2_XATTR_INDEX_USER,
+			      name, value, size, flags);
+}
+
+const struct xattr_handler ext2_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.list	= ext2_xattr_user_list,
+	.get	= ext2_xattr_user_get,
+	.set	= ext2_xattr_user_set,
+};
diff --git a/fs/ext2/xip.c b/fs/ext2/xip.c
new file mode 100644
index 00000000..322a56b2
--- /dev/null
+++ b/fs/ext2/xip.c
@@ -0,0 +1,92 @@
+/*
+ *  linux/fs/ext2/xip.c
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Carsten Otte (cotte@de.ibm.com)
+ */
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/buffer_head.h>
+#include <linux/ext2_fs_sb.h>
+#include <linux/ext2_fs.h>
+#include <linux/blkdev.h>
+#include "ext2.h"
+#include "xip.h"
+
+static inline int
+__inode_direct_access(struct inode *inode, sector_t block,
+		      void **kaddr, unsigned long *pfn)
+{
+	struct block_device *bdev = inode->i_sb->s_bdev;
+	const struct block_device_operations *ops = bdev->bd_disk->fops;
+	sector_t sector;
+
+	sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */
+
+	BUG_ON(!ops->direct_access);
+	return ops->direct_access(bdev, sector, kaddr, pfn);
+}
+
+static inline int
+__ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
+		   sector_t *result)
+{
+	struct buffer_head tmp;
+	int rc;
+
+	memset(&tmp, 0, sizeof(struct buffer_head));
+	rc = ext2_get_block(inode, pgoff, &tmp, create);
+	*result = tmp.b_blocknr;
+
+	/* did we get a sparse block (hole in the file)? */
+	if (!tmp.b_blocknr && !rc) {
+		BUG_ON(create);
+		rc = -ENODATA;
+	}
+
+	return rc;
+}
+
+int
+ext2_clear_xip_target(struct inode *inode, sector_t block)
+{
+	void *kaddr;
+	unsigned long pfn;
+	int rc;
+
+	rc = __inode_direct_access(inode, block, &kaddr, &pfn);
+	if (!rc)
+		clear_page(kaddr);
+	return rc;
+}
+
+void ext2_xip_verify_sb(struct super_block *sb)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
+	    !sb->s_bdev->bd_disk->fops->direct_access) {
+		sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
+		ext2_msg(sb, KERN_WARNING,
+			     "warning: ignoring xip option - "
+			     "not supported by bdev");
+	}
+}
+
+int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
+				void **kmem, unsigned long *pfn)
+{
+	int rc;
+	sector_t block;
+
+	/* first, retrieve the sector number */
+	rc = __ext2_get_block(mapping->host, pgoff, create, &block);
+	if (rc)
+		return rc;
+
+	/* retrieve address of the target data */
+	rc = __inode_direct_access(mapping->host, block, kmem, pfn);
+	return rc;
+}
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
new file mode 100644
index 00000000..18b34d2f
--- /dev/null
+++ b/fs/ext2/xip.h
@@ -0,0 +1,26 @@
+/*
+ *  linux/fs/ext2/xip.h
+ *
+ * Copyright (C) 2005 IBM Corporation
+ * Author: Carsten Otte (cotte@de.ibm.com)
+ */
+
+#ifdef CONFIG_EXT2_FS_XIP
+extern void ext2_xip_verify_sb (struct super_block *);
+extern int ext2_clear_xip_target (struct inode *, sector_t);
+
+static inline int ext2_use_xip (struct super_block *sb)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	return (sbi->s_mount_opt & EXT2_MOUNT_XIP);
+}
+int ext2_get_xip_mem(struct address_space *, pgoff_t, int,
+				void **, unsigned long *);
+#define mapping_is_xip(map) unlikely(map->a_ops->get_xip_mem)
+#else
+#define mapping_is_xip(map)			0
+#define ext2_xip_verify_sb(sb)			do { } while (0)
+#define ext2_use_xip(sb)			0
+#define ext2_clear_xip_target(inode, chain)	0
+#define ext2_get_xip_mem			NULL
+#endif