diff options
| author | Jan Kara <jack@suse.cz> | 2023-03-01 15:10:04 +0100 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2023-03-08 03:45:38 +0100 |
| commit | 3c92792da8506a295afb6d032b4476e46f979725 (patch) | |
| tree | 92613efa0c13d22c51e0f24709db7e9409f8e0e4 /fs/ext4/namei.c | |
| parent | ext4: Fix comment about the 64BIT feature (diff) | |
| download | linux-3c92792da8506a295afb6d032b4476e46f979725.tar.xz linux-3c92792da8506a295afb6d032b4476e46f979725.zip | |
ext4: Fix deadlock during directory rename
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>
Diffstat (limited to '')
| -rw-r--r-- | fs/ext4/namei.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index e8f429330f3c..7cc3918e2f18 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3813,10 +3813,20 @@ 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 @@ -3873,11 +3883,6 @@ 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); @@ -4014,12 +4019,15 @@ end_rename: } 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; } |