From 0c440f14558bfacd22c6935ae1fd4b2a09e96b5d Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Thu, 26 Jan 2023 12:22:21 +0100 Subject: [PATCH] ext4: Fix possible corruption when moving a directory [ 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 Link: https://lore.kernel.org/r/20230126112221.11866-1-jack@suse.cz Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- 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 6f335d58183e..17590bb76914 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3923,9 +3923,16 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 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 @@ -4050,6 +4057,8 @@ end_rename: } else { ext4_journal_stop(handle); } + if (old.dir_bh) + inode_unlock(old.inode); release_bh: brelse(old.dir_bh); brelse(old.bh);