From: "zhangyi (F)" yi.zhang@huawei.com
hulk inclusion category: bugfix bugzilla: 49893 CVE: NA ---------------------------
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.
Fixes: 21401081d4e ("ext4: fix bug for rename with RENAME_WHITEOUT") Signed-off-by: zhangyi (F) yi.zhang@huawei.com Reviewed-by: Yang Erkun yangerkun@huawei.com Reviewed-by: Ye bin yebin10@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/ext4/namei.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 558d8d9b8b224..a8face65e5fd4 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3464,6 +3464,31 @@ static int ext4_setent(handle_t *handle, struct ext4_renament *ent, 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de may no longer valid and need to find it again + * before reset old inode info.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) { @@ -3760,8 +3785,8 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 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);