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From: Richard Weinberger <richard@nod.at>
Date: Tue, 13 Sep 2016 16:18:57 +0200
Subject: [PATCH] ubifs: Implement RENAME_EXCHANGE
Adds RENAME_EXCHANGE to UBIFS, the operation itself
is completely disjunct from a regular rename() that's
why we dispatch very early in ubifs_reaname().
RENAME_EXCHANGE used by the renameat2() system call
allows the caller to exchange two paths atomically.
Both paths have to exist and have to be on the same
filesystem.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -1095,11 +1095,6 @@ static int ubifs_rename(struct inode *ol
old_dentry, old_inode->i_ino, old_dir->i_ino,
new_dentry, new_dir->i_ino, flags);
- if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT))
- return -EINVAL;
-
- ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
- ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
if (unlink)
ubifs_assert(mutex_is_locked(&new_inode->i_mutex));
@@ -1284,6 +1279,64 @@ out_cancel:
return err;
}
+static int ubifs_xrename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
+{
+ struct ubifs_info *c = old_dir->i_sb->s_fs_info;
+ struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
+ .dirtied_ino = 2 };
+ int sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
+ struct inode *fst_inode = d_inode(old_dentry);
+ struct inode *snd_inode = d_inode(new_dentry);
+ struct timespec time;
+ int err;
+
+ ubifs_assert(fst_inode && snd_inode);
+
+ lock_4_inodes(old_dir, new_dir, NULL, NULL);
+
+ time = ubifs_current_time(old_dir);
+ fst_inode->i_ctime = time;
+ snd_inode->i_ctime = time;
+ old_dir->i_mtime = old_dir->i_ctime = time;
+ new_dir->i_mtime = new_dir->i_ctime = time;
+
+ if (old_dir != new_dir) {
+ if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
+ inc_nlink(new_dir);
+ drop_nlink(old_dir);
+ }
+ else if (!S_ISDIR(fst_inode->i_mode) && S_ISDIR(snd_inode->i_mode)) {
+ drop_nlink(new_dir);
+ inc_nlink(old_dir);
+ }
+ }
+
+ err = ubifs_jnl_xrename(c, old_dir, old_dentry, new_dir, new_dentry,
+ sync);
+
+ unlock_4_inodes(old_dir, new_dir, NULL, NULL);
+ ubifs_release_budget(c, &req);
+
+ return err;
+}
+
+static int ubifs_rename2(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry,
+ unsigned int flags)
+{
+ if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT | RENAME_EXCHANGE))
+ return -EINVAL;
+
+ ubifs_assert(mutex_is_locked(&old_dir->i_mutex));
+ ubifs_assert(mutex_is_locked(&new_dir->i_mutex));
+
+ if (flags & RENAME_EXCHANGE)
+ return ubifs_xrename(old_dir, old_dentry, new_dir, new_dentry);
+
+ return ubifs_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
+}
+
int ubifs_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
@@ -1332,7 +1385,7 @@ const struct inode_operations ubifs_dir_
.mkdir = ubifs_mkdir,
.rmdir = ubifs_rmdir,
.mknod = ubifs_mknod,
- .rename2 = ubifs_rename,
+ .rename2 = ubifs_rename2,
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
.setxattr = ubifs_setxattr,
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -908,6 +908,147 @@ int ubifs_jnl_delete_inode(struct ubifs_
}
/**
+ * ubifs_jnl_xrename - cross rename two directory entries.
+ * @c: UBIFS file-system description object
+ * @fst_dir: parent inode of 1st directory entry to exchange
+ * @fst_dentry: 1st directory entry to exchange
+ * @snd_dir: parent inode of 2nd directory entry to exchange
+ * @snd_dentry: 2nd directory entry to exchange
+ * @sync: non-zero if the write-buffer has to be synchronized
+ *
+ * This function implements the cross rename operation which may involve
+ * writing 2 inodes and 2 directory entries. It marks the written inodes as clean
+ * and returns zero on success. In case of failure, a negative error code is
+ * returned.
+ */
+int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
+ const struct dentry *fst_dentry,
+ const struct inode *snd_dir,
+ const struct dentry *snd_dentry, int sync)
+{
+ union ubifs_key key;
+ struct ubifs_dent_node *dent1, *dent2;
+ int err, dlen1, dlen2, lnum, offs, len, plen = UBIFS_INO_NODE_SZ;
+ int aligned_dlen1, aligned_dlen2;
+ int twoparents = (fst_dir != snd_dir);
+ const struct inode *fst_inode = d_inode(fst_dentry);
+ const struct inode *snd_inode = d_inode(snd_dentry);
+ void *p;
+
+ dbg_jnl("dent '%pd' in dir ino %lu between dent '%pd' in dir ino %lu",
+ fst_dentry, fst_dir->i_ino, snd_dentry, snd_dir->i_ino);
+
+ ubifs_assert(ubifs_inode(fst_dir)->data_len == 0);
+ ubifs_assert(ubifs_inode(snd_dir)->data_len == 0);
+ ubifs_assert(mutex_is_locked(&ubifs_inode(fst_dir)->ui_mutex));
+ ubifs_assert(mutex_is_locked(&ubifs_inode(snd_dir)->ui_mutex));
+
+ dlen1 = UBIFS_DENT_NODE_SZ + snd_dentry->d_name.len + 1;
+ dlen2 = UBIFS_DENT_NODE_SZ + fst_dentry->d_name.len + 1;
+ aligned_dlen1 = ALIGN(dlen1, 8);
+ aligned_dlen2 = ALIGN(dlen2, 8);
+
+ len = aligned_dlen1 + aligned_dlen2 + ALIGN(plen, 8);
+ if (twoparents)
+ len += plen;
+
+ dent1 = kmalloc(len, GFP_NOFS);
+ if (!dent1)
+ return -ENOMEM;
+
+ /* Make reservation before allocating sequence numbers */
+ err = make_reservation(c, BASEHD, len);
+ if (err)
+ goto out_free;
+
+ /* Make new dent for 1st entry */
+ dent1->ch.node_type = UBIFS_DENT_NODE;
+ dent_key_init_flash(c, &dent1->key, snd_dir->i_ino, &snd_dentry->d_name);
+ dent1->inum = cpu_to_le64(fst_inode->i_ino);
+ dent1->type = get_dent_type(fst_inode->i_mode);
+ dent1->nlen = cpu_to_le16(snd_dentry->d_name.len);
+ memcpy(dent1->name, snd_dentry->d_name.name, snd_dentry->d_name.len);
+ dent1->name[snd_dentry->d_name.len] = '\0';
+ zero_dent_node_unused(dent1);
+ ubifs_prep_grp_node(c, dent1, dlen1, 0);
+
+ /* Make new dent for 2nd entry */
+ dent2 = (void *)dent1 + aligned_dlen1;
+ dent2->ch.node_type = UBIFS_DENT_NODE;
+ dent_key_init_flash(c, &dent2->key, fst_dir->i_ino, &fst_dentry->d_name);
+ dent2->inum = cpu_to_le64(snd_inode->i_ino);
+ dent2->type = get_dent_type(snd_inode->i_mode);
+ dent2->nlen = cpu_to_le16(fst_dentry->d_name.len);
+ memcpy(dent2->name, fst_dentry->d_name.name, fst_dentry->d_name.len);
+ dent2->name[fst_dentry->d_name.len] = '\0';
+ zero_dent_node_unused(dent2);
+ ubifs_prep_grp_node(c, dent2, dlen2, 0);
+
+ p = (void *)dent2 + aligned_dlen2;
+ if (!twoparents)
+ pack_inode(c, p, fst_dir, 1);
+ else {
+ pack_inode(c, p, fst_dir, 0);
+ p += ALIGN(plen, 8);
+ pack_inode(c, p, snd_dir, 1);
+ }
+
+ err = write_head(c, BASEHD, dent1, len, &lnum, &offs, sync);
+ if (err)
+ goto out_release;
+ if (!sync) {
+ struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+ ubifs_wbuf_add_ino_nolock(wbuf, fst_dir->i_ino);
+ ubifs_wbuf_add_ino_nolock(wbuf, snd_dir->i_ino);
+ }
+ release_head(c, BASEHD);
+
+ dent_key_init(c, &key, snd_dir->i_ino, &snd_dentry->d_name);
+ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen1, &snd_dentry->d_name);
+ if (err)
+ goto out_ro;
+
+ offs += aligned_dlen1;
+ dent_key_init(c, &key, fst_dir->i_ino, &fst_dentry->d_name);
+ err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen2, &fst_dentry->d_name);
+ if (err)
+ goto out_ro;
+
+ offs += aligned_dlen2;
+
+ ino_key_init(c, &key, fst_dir->i_ino);
+ err = ubifs_tnc_add(c, &key, lnum, offs, plen);
+ if (err)
+ goto out_ro;
+
+ if (twoparents) {
+ offs += ALIGN(plen, 8);
+ ino_key_init(c, &key, snd_dir->i_ino);
+ err = ubifs_tnc_add(c, &key, lnum, offs, plen);
+ if (err)
+ goto out_ro;
+ }
+
+ finish_reservation(c);
+
+ mark_inode_clean(c, ubifs_inode(fst_dir));
+ if (twoparents)
+ mark_inode_clean(c, ubifs_inode(snd_dir));
+ kfree(dent1);
+ return 0;
+
+out_release:
+ release_head(c, BASEHD);
+out_ro:
+ ubifs_ro_mode(c, err);
+ finish_reservation(c);
+out_free:
+ kfree(dent1);
+ return err;
+}
+
+/**
* ubifs_jnl_rename - rename a directory entry.
* @c: UBIFS file-system description object
* @old_dir: parent inode of directory entry to rename
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1544,6 +1544,10 @@ int ubifs_jnl_write_data(struct ubifs_in
const union ubifs_key *key, const void *buf, int len);
int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode);
int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode);
+int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
+ const struct dentry *fst_dentry,
+ const struct inode *snd_dir,
+ const struct dentry *snd_dentry, int sync);
int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
const struct dentry *old_dentry,
const struct inode *new_dir,
|
