From: Jan Kara jack@suse.cz
[ Upstream commit 3c92792da8506a295afb6d032b4476e46f979725 ]
As lockdep properly warns, we should not be locking i_rwsem while having transactions started as the proper lock ordering used by all directory handling operations is i_rwsem -> transaction start. Fix the lock ordering by moving the locking of the directory earlier in ext4_rename().
Reported-by: syzbot+9d16c39efb5fade84574@syzkaller.appspotmail.com Fixes: 0813299c586b ("ext4: Fix possible corruption when moving a directory") Link: https://syzkaller.appspot.com/bug?extid=9d16c39efb5fade84574 Signed-off-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20230301141004.15087-1-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/namei.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index aa689adeeafdf..c79c61002a620 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3827,10 +3827,20 @@ static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir, return retval; }
+ /* + * We need to protect against old.inode directory getting converted + * from inline directory format into a normal one. + */ + if (S_ISDIR(old.inode->i_mode)) + inode_lock_nested(old.inode, I_MUTEX_NONDIR2); + old.bh = ext4_find_entry(old.dir, &old.dentry->d_name, &old.de, &old.inlined); - if (IS_ERR(old.bh)) - return PTR_ERR(old.bh); + if (IS_ERR(old.bh)) { + retval = PTR_ERR(old.bh); + goto unlock_moved_dir; + } + /* * Check for inode number is _not_ due to possible IO errors. * We might rmdir the source, keep it as pwd of some process @@ -3887,11 +3897,6 @@ static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir, if (new.dir != old.dir && EXT4_DIR_LINK_MAX(new.dir)) goto end_rename; } - /* - * We need to protect against old.inode directory getting - * converted from inline directory format into a normal one. - */ - inode_lock_nested(old.inode, I_MUTEX_NONDIR2); retval = ext4_rename_dir_prepare(handle, &old); if (retval) { inode_unlock(old.inode); @@ -4021,12 +4026,15 @@ static int ext4_rename(struct user_namespace *mnt_userns, struct inode *old_dir, } else { ext4_journal_stop(handle); } - if (old.dir_bh) - inode_unlock(old.inode); release_bh: brelse(old.dir_bh); brelse(old.bh); brelse(new.bh); + +unlock_moved_dir: + if (S_ISDIR(old.inode->i_mode)) + inode_unlock(old.inode); + return retval; }