[PATCH 4.19 39/43] ext4: find old entry again if failed to rename whiteout

Greg Kroah-Hartman
2021-03-22T13:04:16Z

From: zhangyi (F) <yi.zhang@huawei.com>

commit b7ff91fd030dc9d72ed91b1aab36e445a003af4f upstream.

If we failed to add new entry on rename whiteout, we cannot reset the
old->de entry directly, because the old->de could have moved from under
us during make indexed dir. So find the old entry again before reset is
needed, otherwise it may corrupt the filesystem as below.

/dev/sda: Entry '00000001' in ??? (12) has deleted/unused inode 15. CLEARED.
/dev/sda: Unattached inode 75
/dev/sda: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.

Fixes: 6b4b8e6b4ad ("ext4: fix bug for rename with RENAME_WHITEOUT")
Cc: stable@vger.kernel.org
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20210303131703.330415-1-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ext4/namei.c | 29 +++++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)

--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3440,6 +3440,31 @@ static int ext4_setent(handle_t *handle,
return 0;
}

+static void ext4_resetent(handle_t *handle, struct ext4_renament *ent,
+ unsigned ino, unsigned file_type)
+{
+ struct ext4_renament old = *ent;
+ int retval = 0;
+
+ /*
+ * old->de could have moved from under us during make indexed dir,
+ * so the old->de may no longer valid and need to find it again
+ * before reset old inode info.
+ */
+ old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, NULL);
+ if (IS_ERR(old.bh))
+ retval = PTR_ERR(old.bh);
+ if (!old.bh)
+ retval = -ENOENT;
+ if (retval) {
+ ext4_std_error(old.dir->i_sb, retval);
+ return;
+ }
+
+ ext4_setent(handle, &old, ino, file_type);
+ brelse(old.bh);
+}
+
static int ext4_find_delete_entry(handle_t *handle, struct inode *dir,
const struct qstr *d_name)
{
@@ -3736,8 +3761,8 @@ static int ext4_rename(struct inode *old
end_rename:
if (whiteout) {
if (retval) {
- ext4_setent(handle, &old,
- old.inode->i_ino, old_file_type);
+ ext4_resetent(handle, &old,
+ old.inode->i_ino, old_file_type);
drop_nlink(whiteout);
}
unlock_new_inode(whiteout);