From: Jan Kara jack@suse.cz
[ Upstream commit 0813299c586b175d7edb25f56412c54b812d0379 ]
When we are renaming a directory to a different directory, we need to update '..' entry in the moved directory. However nothing prevents moved directory from being modified and even converted from the inline format to the normal format. When such race happens the rename code gets confused and we crash. Fix the problem by locking the moved directory.
CC: stable@vger.kernel.org Fixes: 32f7f22c0b52 ("ext4: let ext4_rename handle inline dir") Signed-off-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20230126112221.11866-1-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext4/namei.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 924e16b239e07..e8f429330f3c3 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3873,9 +3873,16 @@ 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) + if (retval) { + inode_unlock(old.inode); goto end_rename; + } } /* * If we're renaming a file within an inline_data dir and adding or @@ -4007,6 +4014,8 @@ 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);