initial_commit

6 files changed, 1149 insertions, 0 deletions

diff --git a/fs/bfs/Kconfig b/fs/bfs/Kconfig
new file mode 100644
index 00000000..c2336c62
--- /dev/null
+++ b/fs/bfs/Kconfig
@@ -0,0 +1,19 @@
+config BFS_FS
+	tristate "BFS file system support (EXPERIMENTAL)"
+	depends on BLOCK && EXPERIMENTAL
+	help
+	  Boot File System (BFS) is a file system used under SCO UnixWare to
+	  allow the bootloader access to the kernel image and other important
+	  files during the boot process.  It is usually mounted under /stand
+	  and corresponds to the slice marked as "STAND" in the UnixWare
+	  partition.  You should say Y if you want to read or write the files
+	  on your /stand slice from within Linux.  You then also need to say Y
+	  to "UnixWare slices support", below.  More information about the BFS
+	  file system is contained in the file
+	  <file:Documentation/filesystems/bfs.txt>.
+
+	  If you don't know what this is about, say N.
+
+	  To compile this as a module, choose M here: the module will be called
+	  bfs.  Note that the file system of your root partition (the one
+	  containing the directory /) cannot be compiled as a module.
diff --git a/fs/bfs/Makefile b/fs/bfs/Makefile
new file mode 100644
index 00000000..c787b36d
--- /dev/null
+++ b/fs/bfs/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for BFS filesystem.
+#
+
+obj-$(CONFIG_BFS_FS) += bfs.o
+
+bfs-objs := inode.o file.o dir.o
diff --git a/fs/bfs/bfs.h b/fs/bfs/bfs.h
new file mode 100644
index 00000000..f7f87e23
--- /dev/null
+++ b/fs/bfs/bfs.h
@@ -0,0 +1,59 @@
+/*
+ *	fs/bfs/bfs.h
+ *	Copyright (C) 1999 Tigran Aivazian <tigran@veritas.com>
+ */
+#ifndef _FS_BFS_BFS_H
+#define _FS_BFS_BFS_H
+
+#include <linux/bfs_fs.h>
+
+/*
+ * BFS file system in-core superblock info
+ */
+struct bfs_sb_info {
+	unsigned long si_blocks;
+	unsigned long si_freeb;
+	unsigned long si_freei;
+	unsigned long si_lf_eblk;
+	unsigned long si_lasti;
+	unsigned long *si_imap;
+	struct mutex bfs_lock;
+};
+
+/*
+ * BFS file system in-core inode info
+ */
+struct bfs_inode_info {
+	unsigned long i_dsk_ino; /* inode number from the disk, can be 0 */
+	unsigned long i_sblock;
+	unsigned long i_eblock;
+	struct inode vfs_inode;
+};
+
+static inline struct bfs_sb_info *BFS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct bfs_inode_info *BFS_I(struct inode *inode)
+{
+	return container_of(inode, struct bfs_inode_info, vfs_inode);
+}
+
+
+#define printf(format, args...) \
+	printk(KERN_ERR "BFS-fs: %s(): " format, __func__, ## args)
+
+/* inode.c */
+extern struct inode *bfs_iget(struct super_block *sb, unsigned long ino);
+
+/* file.c */
+extern const struct inode_operations bfs_file_inops;
+extern const struct file_operations bfs_file_operations;
+extern const struct address_space_operations bfs_aops;
+
+/* dir.c */
+extern const struct inode_operations bfs_dir_inops;
+extern const struct file_operations bfs_dir_operations;
+
+#endif /* _FS_BFS_BFS_H */
diff --git a/fs/bfs/dir.c b/fs/bfs/dir.c
new file mode 100644
index 00000000..b14cebfd
--- /dev/null
+++ b/fs/bfs/dir.c
@@ -0,0 +1,374 @@
+/*
+ *	fs/bfs/dir.c
+ *	BFS directory operations.
+ *	Copyright (C) 1999,2000  Tigran Aivazian <tigran@veritas.com>
+ *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
+ */
+
+#include <linux/time.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/sched.h>
+#include "bfs.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...)	printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+static int bfs_add_entry(struct inode *dir, const unsigned char *name,
+						int namelen, int ino);
+static struct buffer_head *bfs_find_entry(struct inode *dir,
+				const unsigned char *name, int namelen,
+				struct bfs_dirent **res_dir);
+
+static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir)
+{
+	struct inode *dir = f->f_path.dentry->d_inode;
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
+	unsigned int offset;
+	int block;
+
+	mutex_lock(&info->bfs_lock);
+
+	if (f->f_pos & (BFS_DIRENT_SIZE - 1)) {
+		printf("Bad f_pos=%08lx for %s:%08lx\n",
+					(unsigned long)f->f_pos,
+					dir->i_sb->s_id, dir->i_ino);
+		mutex_unlock(&info->bfs_lock);
+		return -EBADF;
+	}
+
+	while (f->f_pos < dir->i_size) {
+		offset = f->f_pos & (BFS_BSIZE - 1);
+		block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
+		bh = sb_bread(dir->i_sb, block);
+		if (!bh) {
+			f->f_pos += BFS_BSIZE - offset;
+			continue;
+		}
+		do {
+			de = (struct bfs_dirent *)(bh->b_data + offset);
+			if (de->ino) {
+				int size = strnlen(de->name, BFS_NAMELEN);
+				if (filldir(dirent, de->name, size, f->f_pos,
+						le16_to_cpu(de->ino),
+						DT_UNKNOWN) < 0) {
+					brelse(bh);
+					mutex_unlock(&info->bfs_lock);
+					return 0;
+				}
+			}
+			offset += BFS_DIRENT_SIZE;
+			f->f_pos += BFS_DIRENT_SIZE;
+		} while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size));
+		brelse(bh);
+	}
+
+	mutex_unlock(&info->bfs_lock);
+	return 0;	
+}
+
+const struct file_operations bfs_dir_operations = {
+	.read		= generic_read_dir,
+	.readdir	= bfs_readdir,
+	.fsync		= generic_file_fsync,
+	.llseek		= generic_file_llseek,
+};
+
+extern void dump_imap(const char *, struct super_block *);
+
+static int bfs_create(struct inode *dir, struct dentry *dentry, int mode,
+						struct nameidata *nd)
+{
+	int err;
+	struct inode *inode;
+	struct super_block *s = dir->i_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	unsigned long ino;
+
+	inode = new_inode(s);
+	if (!inode)
+		return -ENOSPC;
+	mutex_lock(&info->bfs_lock);
+	ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1);
+	if (ino > info->si_lasti) {
+		mutex_unlock(&info->bfs_lock);
+		iput(inode);
+		return -ENOSPC;
+	}
+	set_bit(ino, info->si_imap);
+	info->si_freei--;
+	inode_init_owner(inode, dir, mode);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
+	inode->i_blocks = 0;
+	inode->i_op = &bfs_file_inops;
+	inode->i_fop = &bfs_file_operations;
+	inode->i_mapping->a_ops = &bfs_aops;
+	inode->i_ino = ino;
+	BFS_I(inode)->i_dsk_ino = ino;
+	BFS_I(inode)->i_sblock = 0;
+	BFS_I(inode)->i_eblock = 0;
+	insert_inode_hash(inode);
+        mark_inode_dirty(inode);
+	dump_imap("create", s);
+
+	err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len,
+							inode->i_ino);
+	if (err) {
+		inode_dec_link_count(inode);
+		mutex_unlock(&info->bfs_lock);
+		iput(inode);
+		return err;
+	}
+	mutex_unlock(&info->bfs_lock);
+	d_instantiate(dentry, inode);
+	return 0;
+}
+
+static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry,
+						struct nameidata *nd)
+{
+	struct inode *inode = NULL;
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	struct bfs_sb_info *info = BFS_SB(dir->i_sb);
+
+	if (dentry->d_name.len > BFS_NAMELEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	mutex_lock(&info->bfs_lock);
+	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
+	if (bh) {
+		unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
+		brelse(bh);
+		inode = bfs_iget(dir->i_sb, ino);
+		if (IS_ERR(inode)) {
+			mutex_unlock(&info->bfs_lock);
+			return ERR_CAST(inode);
+		}
+	}
+	mutex_unlock(&info->bfs_lock);
+	d_add(dentry, inode);
+	return NULL;
+}
+
+static int bfs_link(struct dentry *old, struct inode *dir,
+						struct dentry *new)
+{
+	struct inode *inode = old->d_inode;
+	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
+	int err;
+
+	mutex_lock(&info->bfs_lock);
+	err = bfs_add_entry(dir, new->d_name.name, new->d_name.len,
+							inode->i_ino);
+	if (err) {
+		mutex_unlock(&info->bfs_lock);
+		return err;
+	}
+	inc_nlink(inode);
+	inode->i_ctime = CURRENT_TIME_SEC;
+	mark_inode_dirty(inode);
+	ihold(inode);
+	d_instantiate(new, inode);
+	mutex_unlock(&info->bfs_lock);
+	return 0;
+}
+
+static int bfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	int error = -ENOENT;
+	struct inode *inode = dentry->d_inode;
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
+
+	mutex_lock(&info->bfs_lock);
+	bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
+	if (!bh || (le16_to_cpu(de->ino) != inode->i_ino))
+		goto out_brelse;
+
+	if (!inode->i_nlink) {
+		printf("unlinking non-existent file %s:%lu (nlink=%d)\n",
+					inode->i_sb->s_id, inode->i_ino,
+					inode->i_nlink);
+		inode->i_nlink = 1;
+	}
+	de->ino = 0;
+	mark_buffer_dirty_inode(bh, dir);
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
+	mark_inode_dirty(dir);
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+	error = 0;
+
+out_brelse:
+	brelse(bh);
+	mutex_unlock(&info->bfs_lock);
+	return error;
+}
+
+static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct inode *old_inode, *new_inode;
+	struct buffer_head *old_bh, *new_bh;
+	struct bfs_dirent *old_de, *new_de;
+	struct bfs_sb_info *info;
+	int error = -ENOENT;
+
+	old_bh = new_bh = NULL;
+	old_inode = old_dentry->d_inode;
+	if (S_ISDIR(old_inode->i_mode))
+		return -EINVAL;
+
+	info = BFS_SB(old_inode->i_sb);
+
+	mutex_lock(&info->bfs_lock);
+	old_bh = bfs_find_entry(old_dir, 
+				old_dentry->d_name.name, 
+				old_dentry->d_name.len, &old_de);
+
+	if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino))
+		goto end_rename;
+
+	error = -EPERM;
+	new_inode = new_dentry->d_inode;
+	new_bh = bfs_find_entry(new_dir, 
+				new_dentry->d_name.name, 
+				new_dentry->d_name.len, &new_de);
+
+	if (new_bh && !new_inode) {
+		brelse(new_bh);
+		new_bh = NULL;
+	}
+	if (!new_bh) {
+		error = bfs_add_entry(new_dir, 
+					new_dentry->d_name.name,
+					new_dentry->d_name.len,
+					old_inode->i_ino);
+		if (error)
+			goto end_rename;
+	}
+	old_de->ino = 0;
+	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
+	mark_inode_dirty(old_dir);
+	if (new_inode) {
+		new_inode->i_ctime = CURRENT_TIME_SEC;
+		inode_dec_link_count(new_inode);
+	}
+	mark_buffer_dirty_inode(old_bh, old_dir);
+	error = 0;
+
+end_rename:
+	mutex_unlock(&info->bfs_lock);
+	brelse(old_bh);
+	brelse(new_bh);
+	return error;
+}
+
+const struct inode_operations bfs_dir_inops = {
+	.create			= bfs_create,
+	.lookup			= bfs_lookup,
+	.link			= bfs_link,
+	.unlink			= bfs_unlink,
+	.rename			= bfs_rename,
+};
+
+static int bfs_add_entry(struct inode *dir, const unsigned char *name,
+							int namelen, int ino)
+{
+	struct buffer_head *bh;
+	struct bfs_dirent *de;
+	int block, sblock, eblock, off, pos;
+	int i;
+
+	dprintf("name=%s, namelen=%d\n", name, namelen);
+
+	if (!namelen)
+		return -ENOENT;
+	if (namelen > BFS_NAMELEN)
+		return -ENAMETOOLONG;
+
+	sblock = BFS_I(dir)->i_sblock;
+	eblock = BFS_I(dir)->i_eblock;
+	for (block = sblock; block <= eblock; block++) {
+		bh = sb_bread(dir->i_sb, block);
+		if (!bh)
+			return -ENOSPC;
+		for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) {
+			de = (struct bfs_dirent *)(bh->b_data + off);
+			if (!de->ino) {
+				pos = (block - sblock) * BFS_BSIZE + off;
+				if (pos >= dir->i_size) {
+					dir->i_size += BFS_DIRENT_SIZE;
+					dir->i_ctime = CURRENT_TIME_SEC;
+				}
+				dir->i_mtime = CURRENT_TIME_SEC;
+				mark_inode_dirty(dir);
+				de->ino = cpu_to_le16((u16)ino);
+				for (i = 0; i < BFS_NAMELEN; i++)
+					de->name[i] =
+						(i < namelen) ? name[i] : 0;
+				mark_buffer_dirty_inode(bh, dir);
+				brelse(bh);
+				return 0;
+			}
+		}
+		brelse(bh);
+	}
+	return -ENOSPC;
+}
+
+static inline int bfs_namecmp(int len, const unsigned char *name,
+							const char *buffer)
+{
+	if ((len < BFS_NAMELEN) && buffer[len])
+		return 0;
+	return !memcmp(name, buffer, len);
+}
+
+static struct buffer_head *bfs_find_entry(struct inode *dir,
+			const unsigned char *name, int namelen,
+			struct bfs_dirent **res_dir)
+{
+	unsigned long block = 0, offset = 0;
+	struct buffer_head *bh = NULL;
+	struct bfs_dirent *de;
+
+	*res_dir = NULL;
+	if (namelen > BFS_NAMELEN)
+		return NULL;
+
+	while (block * BFS_BSIZE + offset < dir->i_size) {
+		if (!bh) {
+			bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
+			if (!bh) {
+				block++;
+				continue;
+			}
+		}
+		de = (struct bfs_dirent *)(bh->b_data + offset);
+		offset += BFS_DIRENT_SIZE;
+		if (le16_to_cpu(de->ino) &&
+				bfs_namecmp(namelen, name, de->name)) {
+			*res_dir = de;
+			return bh;
+		}
+		if (offset < bh->b_size)
+			continue;
+		brelse(bh);
+		bh = NULL;
+		offset = 0;
+		block++;
+	}
+	brelse(bh);
+	return NULL;
+}
diff --git a/fs/bfs/file.c b/fs/bfs/file.c
new file mode 100644
index 00000000..f20e8a71
--- /dev/null
+++ b/fs/bfs/file.c
@@ -0,0 +1,194 @@
+/*
+ *	fs/bfs/file.c
+ *	BFS file operations.
+ *	Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
+ *
+ *	Make the file block allocation algorithm understand the size
+ *	of the underlying block device.
+ *	Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include "bfs.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...)	printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+const struct file_operations bfs_file_operations = {
+	.llseek 	= generic_file_llseek,
+	.read		= do_sync_read,
+	.aio_read	= generic_file_aio_read,
+	.write		= do_sync_write,
+	.aio_write	= generic_file_aio_write,
+	.mmap		= generic_file_mmap,
+	.splice_read	= generic_file_splice_read,
+};
+
+static int bfs_move_block(unsigned long from, unsigned long to,
+					struct super_block *sb)
+{
+	struct buffer_head *bh, *new;
+
+	bh = sb_bread(sb, from);
+	if (!bh)
+		return -EIO;
+	new = sb_getblk(sb, to);
+	memcpy(new->b_data, bh->b_data, bh->b_size);
+	mark_buffer_dirty(new);
+	bforget(bh);
+	brelse(new);
+	return 0;
+}
+
+static int bfs_move_blocks(struct super_block *sb, unsigned long start,
+				unsigned long end, unsigned long where)
+{
+	unsigned long i;
+
+	dprintf("%08lx-%08lx->%08lx\n", start, end, where);
+	for (i = start; i <= end; i++)
+		if(bfs_move_block(i, where + i, sb)) {
+			dprintf("failed to move block %08lx -> %08lx\n", i,
+								where + i);
+			return -EIO;
+		}
+	return 0;
+}
+
+static int bfs_get_block(struct inode *inode, sector_t block,
+			struct buffer_head *bh_result, int create)
+{
+	unsigned long phys;
+	int err;
+	struct super_block *sb = inode->i_sb;
+	struct bfs_sb_info *info = BFS_SB(sb);
+	struct bfs_inode_info *bi = BFS_I(inode);
+
+	phys = bi->i_sblock + block;
+	if (!create) {
+		if (phys <= bi->i_eblock) {
+			dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
+                                create, (unsigned long)block, phys);
+			map_bh(bh_result, sb, phys);
+		}
+		return 0;
+	}
+
+	/*
+	 * If the file is not empty and the requested block is within the
+	 * range of blocks allocated for this file, we can grant it.
+	 */
+	if (bi->i_sblock && (phys <= bi->i_eblock)) {
+		dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", 
+				create, (unsigned long)block, phys);
+		map_bh(bh_result, sb, phys);
+		return 0;
+	}
+
+	/* The file will be extended, so let's see if there is enough space. */
+	if (phys >= info->si_blocks)
+		return -ENOSPC;
+
+	/* The rest has to be protected against itself. */
+	mutex_lock(&info->bfs_lock);
+
+	/*
+	 * If the last data block for this file is the last allocated
+	 * block, we can extend the file trivially, without moving it
+	 * anywhere.
+	 */
+	if (bi->i_eblock == info->si_lf_eblk) {
+		dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", 
+				create, (unsigned long)block, phys);
+		map_bh(bh_result, sb, phys);
+		info->si_freeb -= phys - bi->i_eblock;
+		info->si_lf_eblk = bi->i_eblock = phys;
+		mark_inode_dirty(inode);
+		err = 0;
+		goto out;
+	}
+
+	/* Ok, we have to move this entire file to the next free block. */
+	phys = info->si_lf_eblk + 1;
+	if (phys + block >= info->si_blocks) {
+		err = -ENOSPC;
+		goto out;
+	}
+
+	if (bi->i_sblock) {
+		err = bfs_move_blocks(inode->i_sb, bi->i_sblock, 
+						bi->i_eblock, phys);
+		if (err) {
+			dprintf("failed to move ino=%08lx -> fs corruption\n",
+								inode->i_ino);
+			goto out;
+		}
+	} else
+		err = 0;
+
+	dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
+                create, (unsigned long)block, phys);
+	bi->i_sblock = phys;
+	phys += block;
+	info->si_lf_eblk = bi->i_eblock = phys;
+
+	/*
+	 * This assumes nothing can write the inode back while we are here
+	 * and thus update inode->i_blocks! (XXX)
+	 */
+	info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
+	mark_inode_dirty(inode);
+	map_bh(bh_result, sb, phys);
+out:
+	mutex_unlock(&info->bfs_lock);
+	return err;
+}
+
+static int bfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	return block_write_full_page(page, bfs_get_block, wbc);
+}
+
+static int bfs_readpage(struct file *file, struct page *page)
+{
+	return block_read_full_page(page, bfs_get_block);
+}
+
+static int bfs_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,
+				bfs_get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
+}
+
+static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
+{
+	return generic_block_bmap(mapping, block, bfs_get_block);
+}
+
+const struct address_space_operations bfs_aops = {
+	.readpage	= bfs_readpage,
+	.writepage	= bfs_writepage,
+	.write_begin	= bfs_write_begin,
+	.write_end	= generic_write_end,
+	.bmap		= bfs_bmap,
+};
+
+const struct inode_operations bfs_file_inops;
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
new file mode 100644
index 00000000..a8e37f81
--- /dev/null
+++ b/fs/bfs/inode.c
@@ -0,0 +1,496 @@
+/*
+ *	fs/bfs/inode.c
+ *	BFS superblock and inode operations.
+ *	Copyright (C) 1999-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
+ *	From fs/minix, Copyright (C) 1991, 1992 Linus Torvalds.
+ *
+ *      Made endianness-clean by Andrew Stribblehill <ads@wompom.org>, 2005.
+ */
+
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/vfs.h>
+#include <linux/writeback.h>
+#include <asm/uaccess.h>
+#include "bfs.h"
+
+MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
+MODULE_DESCRIPTION("SCO UnixWare BFS filesystem for Linux");
+MODULE_LICENSE("GPL");
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...)	printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+void dump_imap(const char *prefix, struct super_block *s);
+
+struct inode *bfs_iget(struct super_block *sb, unsigned long ino)
+{
+	struct bfs_inode *di;
+	struct inode *inode;
+	struct buffer_head *bh;
+	int block, off;
+
+	inode = iget_locked(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+
+	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(inode->i_sb)->si_lasti)) {
+		printf("Bad inode number %s:%08lx\n", inode->i_sb->s_id, ino);
+		goto error;
+	}
+
+	block = (ino - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
+	bh = sb_bread(inode->i_sb, block);
+	if (!bh) {
+		printf("Unable to read inode %s:%08lx\n", inode->i_sb->s_id,
+									ino);
+		goto error;
+	}
+
+	off = (ino - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
+	di = (struct bfs_inode *)bh->b_data + off;
+
+	inode->i_mode = 0x0000FFFF & le32_to_cpu(di->i_mode);
+	if (le32_to_cpu(di->i_vtype) == BFS_VDIR) {
+		inode->i_mode |= S_IFDIR;
+		inode->i_op = &bfs_dir_inops;
+		inode->i_fop = &bfs_dir_operations;
+	} else if (le32_to_cpu(di->i_vtype) == BFS_VREG) {
+		inode->i_mode |= S_IFREG;
+		inode->i_op = &bfs_file_inops;
+		inode->i_fop = &bfs_file_operations;
+		inode->i_mapping->a_ops = &bfs_aops;
+	}
+
+	BFS_I(inode)->i_sblock =  le32_to_cpu(di->i_sblock);
+	BFS_I(inode)->i_eblock =  le32_to_cpu(di->i_eblock);
+	BFS_I(inode)->i_dsk_ino = le16_to_cpu(di->i_ino);
+	inode->i_uid =  le32_to_cpu(di->i_uid);
+	inode->i_gid =  le32_to_cpu(di->i_gid);
+	inode->i_nlink =  le32_to_cpu(di->i_nlink);
+	inode->i_size = BFS_FILESIZE(di);
+	inode->i_blocks = BFS_FILEBLOCKS(di);
+	inode->i_atime.tv_sec =  le32_to_cpu(di->i_atime);
+	inode->i_mtime.tv_sec =  le32_to_cpu(di->i_mtime);
+	inode->i_ctime.tv_sec =  le32_to_cpu(di->i_ctime);
+	inode->i_atime.tv_nsec = 0;
+	inode->i_mtime.tv_nsec = 0;
+	inode->i_ctime.tv_nsec = 0;
+
+	brelse(bh);
+	unlock_new_inode(inode);
+	return inode;
+
+error:
+	iget_failed(inode);
+	return ERR_PTR(-EIO);
+}
+
+static struct bfs_inode *find_inode(struct super_block *sb, u16 ino, struct buffer_head **p)
+{
+	if ((ino < BFS_ROOT_INO) || (ino > BFS_SB(sb)->si_lasti)) {
+		printf("Bad inode number %s:%08x\n", sb->s_id, ino);
+		return ERR_PTR(-EIO);
+	}
+
+	ino -= BFS_ROOT_INO;
+
+	*p = sb_bread(sb, 1 + ino / BFS_INODES_PER_BLOCK);
+	if (!*p) {
+		printf("Unable to read inode %s:%08x\n", sb->s_id, ino);
+		return ERR_PTR(-EIO);
+	}
+
+	return (struct bfs_inode *)(*p)->b_data +  ino % BFS_INODES_PER_BLOCK;
+}
+
+static int bfs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	struct bfs_sb_info *info = BFS_SB(inode->i_sb);
+	unsigned int ino = (u16)inode->i_ino;
+        unsigned long i_sblock;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
+	int err = 0;
+
+        dprintf("ino=%08x\n", ino);
+
+	di = find_inode(inode->i_sb, ino, &bh);
+	if (IS_ERR(di))
+		return PTR_ERR(di);
+
+	mutex_lock(&info->bfs_lock);
+
+	if (ino == BFS_ROOT_INO)
+		di->i_vtype = cpu_to_le32(BFS_VDIR);
+	else
+		di->i_vtype = cpu_to_le32(BFS_VREG);
+
+	di->i_ino = cpu_to_le16(ino);
+	di->i_mode = cpu_to_le32(inode->i_mode);
+	di->i_uid = cpu_to_le32(inode->i_uid);
+	di->i_gid = cpu_to_le32(inode->i_gid);
+	di->i_nlink = cpu_to_le32(inode->i_nlink);
+	di->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
+	di->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
+	di->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
+        i_sblock = BFS_I(inode)->i_sblock;
+	di->i_sblock = cpu_to_le32(i_sblock);
+	di->i_eblock = cpu_to_le32(BFS_I(inode)->i_eblock);
+	di->i_eoffset = cpu_to_le32(i_sblock * BFS_BSIZE + inode->i_size - 1);
+
+	mark_buffer_dirty(bh);
+	if (wbc->sync_mode == WB_SYNC_ALL) {
+		sync_dirty_buffer(bh);
+		if (buffer_req(bh) && !buffer_uptodate(bh))
+			err = -EIO;
+	}
+	brelse(bh);
+	mutex_unlock(&info->bfs_lock);
+	return err;
+}
+
+static void bfs_evict_inode(struct inode *inode)
+{
+	unsigned long ino = inode->i_ino;
+	struct bfs_inode *di;
+	struct buffer_head *bh;
+	struct super_block *s = inode->i_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	struct bfs_inode_info *bi = BFS_I(inode);
+
+	dprintf("ino=%08lx\n", ino);
+
+	truncate_inode_pages(&inode->i_data, 0);
+	invalidate_inode_buffers(inode);
+	end_writeback(inode);
+
+	if (inode->i_nlink)
+		return;
+
+	di = find_inode(s, inode->i_ino, &bh);
+	if (IS_ERR(di))
+		return;
+
+	mutex_lock(&info->bfs_lock);
+	/* clear on-disk inode */
+	memset(di, 0, sizeof(struct bfs_inode));
+	mark_buffer_dirty(bh);
+	brelse(bh);
+
+        if (bi->i_dsk_ino) {
+		if (bi->i_sblock)
+			info->si_freeb += bi->i_eblock + 1 - bi->i_sblock;
+		info->si_freei++;
+		clear_bit(ino, info->si_imap);
+		dump_imap("delete_inode", s);
+        }
+
+	/*
+	 * If this was the last file, make the previous block
+	 * "last block of the last file" even if there is no
+	 * real file there, saves us 1 gap.
+	 */
+	if (info->si_lf_eblk == bi->i_eblock)
+		info->si_lf_eblk = bi->i_sblock - 1;
+	mutex_unlock(&info->bfs_lock);
+}
+
+static void bfs_put_super(struct super_block *s)
+{
+	struct bfs_sb_info *info = BFS_SB(s);
+
+	if (!info)
+		return;
+
+	mutex_destroy(&info->bfs_lock);
+	kfree(info->si_imap);
+	kfree(info);
+	s->s_fs_info = NULL;
+}
+
+static int bfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *s = dentry->d_sb;
+	struct bfs_sb_info *info = BFS_SB(s);
+	u64 id = huge_encode_dev(s->s_bdev->bd_dev);
+	buf->f_type = BFS_MAGIC;
+	buf->f_bsize = s->s_blocksize;
+	buf->f_blocks = info->si_blocks;
+	buf->f_bfree = buf->f_bavail = info->si_freeb;
+	buf->f_files = info->si_lasti + 1 - BFS_ROOT_INO;
+	buf->f_ffree = info->si_freei;
+	buf->f_fsid.val[0] = (u32)id;
+	buf->f_fsid.val[1] = (u32)(id >> 32);
+	buf->f_namelen = BFS_NAMELEN;
+	return 0;
+}
+
+static struct kmem_cache *bfs_inode_cachep;
+
+static struct inode *bfs_alloc_inode(struct super_block *sb)
+{
+	struct bfs_inode_info *bi;
+	bi = kmem_cache_alloc(bfs_inode_cachep, GFP_KERNEL);
+	if (!bi)
+		return NULL;
+	return &bi->vfs_inode;
+}
+
+static void bfs_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(bfs_inode_cachep, BFS_I(inode));
+}
+
+static void bfs_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, bfs_i_callback);
+}
+
+static void init_once(void *foo)
+{
+	struct bfs_inode_info *bi = foo;
+
+	inode_init_once(&bi->vfs_inode);
+}
+
+static int init_inodecache(void)
+{
+	bfs_inode_cachep = kmem_cache_create("bfs_inode_cache",
+					     sizeof(struct bfs_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD),
+					     init_once);
+	if (bfs_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	kmem_cache_destroy(bfs_inode_cachep);
+}
+
+static const struct super_operations bfs_sops = {
+	.alloc_inode	= bfs_alloc_inode,
+	.destroy_inode	= bfs_destroy_inode,
+	.write_inode	= bfs_write_inode,
+	.evict_inode	= bfs_evict_inode,
+	.put_super	= bfs_put_super,
+	.statfs		= bfs_statfs,
+};
+
+void dump_imap(const char *prefix, struct super_block *s)
+{
+#ifdef DEBUG
+	int i;
+	char *tmpbuf = (char *)get_zeroed_page(GFP_KERNEL);
+
+	if (!tmpbuf)
+		return;
+	for (i = BFS_SB(s)->si_lasti; i >= 0; i--) {
+		if (i > PAGE_SIZE - 100) break;
+		if (test_bit(i, BFS_SB(s)->si_imap))
+			strcat(tmpbuf, "1");
+		else
+			strcat(tmpbuf, "0");
+	}
+	printf("BFS-fs: %s: lasti=%08lx <%s>\n",
+				prefix, BFS_SB(s)->si_lasti, tmpbuf);
+	free_page((unsigned long)tmpbuf);
+#endif
+}
+
+static int bfs_fill_super(struct super_block *s, void *data, int silent)
+{
+	struct buffer_head *bh, *sbh;
+	struct bfs_super_block *bfs_sb;
+	struct inode *inode;
+	unsigned i, imap_len;
+	struct bfs_sb_info *info;
+	int ret = -EINVAL;
+	unsigned long i_sblock, i_eblock, i_eoff, s_size;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+	mutex_init(&info->bfs_lock);
+	s->s_fs_info = info;
+
+	sb_set_blocksize(s, BFS_BSIZE);
+
+	sbh = sb_bread(s, 0);
+	if (!sbh)
+		goto out;
+	bfs_sb = (struct bfs_super_block *)sbh->b_data;
+	if (le32_to_cpu(bfs_sb->s_magic) != BFS_MAGIC) {
+		if (!silent)
+			printf("No BFS filesystem on %s (magic=%08x)\n", 
+				s->s_id,  le32_to_cpu(bfs_sb->s_magic));
+		goto out1;
+	}
+	if (BFS_UNCLEAN(bfs_sb, s) && !silent)
+		printf("%s is unclean, continuing\n", s->s_id);
+
+	s->s_magic = BFS_MAGIC;
+
+	if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
+		printf("Superblock is corrupted\n");
+		goto out1;
+	}
+
+	info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) /
+					sizeof(struct bfs_inode)
+					+ BFS_ROOT_INO - 1;
+	imap_len = (info->si_lasti / 8) + 1;
+	info->si_imap = kzalloc(imap_len, GFP_KERNEL);
+	if (!info->si_imap)
+		goto out1;
+	for (i = 0; i < BFS_ROOT_INO; i++)
+		set_bit(i, info->si_imap);
+
+	s->s_op = &bfs_sops;
+	inode = bfs_iget(s, BFS_ROOT_INO);
+	if (IS_ERR(inode)) {
+		ret = PTR_ERR(inode);
+		goto out2;
+	}
+	s->s_root = d_alloc_root(inode);
+	if (!s->s_root) {
+		iput(inode);
+		ret = -ENOMEM;
+		goto out2;
+	}
+
+	info->si_blocks = (le32_to_cpu(bfs_sb->s_end) + 1) >> BFS_BSIZE_BITS;
+	info->si_freeb = (le32_to_cpu(bfs_sb->s_end) + 1
+			- le32_to_cpu(bfs_sb->s_start)) >> BFS_BSIZE_BITS;
+	info->si_freei = 0;
+	info->si_lf_eblk = 0;
+
+	/* can we read the last block? */
+	bh = sb_bread(s, info->si_blocks - 1);
+	if (!bh) {
+		printf("Last block not available: %lu\n", info->si_blocks - 1);
+		ret = -EIO;
+		goto out3;
+	}
+	brelse(bh);
+
+	bh = NULL;
+	for (i = BFS_ROOT_INO; i <= info->si_lasti; i++) {
+		struct bfs_inode *di;
+		int block = (i - BFS_ROOT_INO) / BFS_INODES_PER_BLOCK + 1;
+		int off = (i - BFS_ROOT_INO) % BFS_INODES_PER_BLOCK;
+		unsigned long eblock;
+
+		if (!off) {
+			brelse(bh);
+			bh = sb_bread(s, block);
+		}
+
+		if (!bh)
+			continue;
+
+		di = (struct bfs_inode *)bh->b_data + off;
+
+		/* test if filesystem is not corrupted */
+
+		i_eoff = le32_to_cpu(di->i_eoffset);
+		i_sblock = le32_to_cpu(di->i_sblock);
+		i_eblock = le32_to_cpu(di->i_eblock);
+		s_size = le32_to_cpu(bfs_sb->s_end);
+
+		if (i_sblock > info->si_blocks ||
+			i_eblock > info->si_blocks ||
+			i_sblock > i_eblock ||
+			i_eoff > s_size ||
+			i_sblock * BFS_BSIZE > i_eoff) {
+
+			printf("Inode 0x%08x corrupted\n", i);
+
+			brelse(bh);
+			ret = -EIO;
+			goto out3;
+		}
+
+		if (!di->i_ino) {
+			info->si_freei++;
+			continue;
+		}
+		set_bit(i, info->si_imap);
+		info->si_freeb -= BFS_FILEBLOCKS(di);
+
+		eblock =  le32_to_cpu(di->i_eblock);
+		if (eblock > info->si_lf_eblk)
+			info->si_lf_eblk = eblock;
+	}
+	brelse(bh);
+	brelse(sbh);
+	dump_imap("read_super", s);
+	return 0;
+
+out3:
+	dput(s->s_root);
+	s->s_root = NULL;
+out2:
+	kfree(info->si_imap);
+out1:
+	brelse(sbh);
+out:
+	mutex_destroy(&info->bfs_lock);
+	kfree(info);
+	s->s_fs_info = NULL;
+	return ret;
+}
+
+static struct dentry *bfs_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, bfs_fill_super);
+}
+
+static struct file_system_type bfs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "bfs",
+	.mount		= bfs_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init init_bfs_fs(void)
+{
+	int err = init_inodecache();
+	if (err)
+		goto out1;
+        err = register_filesystem(&bfs_fs_type);
+	if (err)
+		goto out;
+	return 0;
+out:
+	destroy_inodecache();
+out1:
+	return err;
+}
+
+static void __exit exit_bfs_fs(void)
+{
+	unregister_filesystem(&bfs_fs_type);
+	destroy_inodecache();
+}
+
+module_init(init_bfs_fs)
+module_exit(exit_bfs_fs)