This is a note to let you know that I've just added the patch titled
ext4: Fix possible corruption when moving a directory
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-possible-corruption-when-moving-a-directory.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a3153ce3caa13735cf8d91037fd2cd07217acf1d
Author: Jan Kara <jack@xxxxxxx>
Date: Thu Jan 26 12:22:21 2023 +0100
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@xxxxxxxxxxxxxxx
Fixes: 32f7f22c0b52 ("ext4: let ext4_rename handle inline dir")
Signed-off-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20230126112221.11866-1-jack@xxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 30c37ef8b8af3..f9d11f59df7d2 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3855,9 +3855,16 @@ 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
@@ -3953,6 +3960,8 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
} else {
ext4_journal_stop(handle);
}
+ if (old.dir_bh)
+ inode_unlock(old.inode);
release_bh:
brelse(old.dir_bh);
brelse(old.bh);
