Commit 7569141e authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: replace BUG_ON() at split_item() with proper error handling 



There's no need to BUG_ON() at split_item() if the leaf does not have
enough free space for the new item, we can just return -ENOSPC since
the caller can deal with errors from split_item(). Also, as this is a
very unlikely condition to happen, because the caller has invoked
setup_leaf_for_split() before calling split_item(), surround the
condition with a WARN_ON() which makes it easier to notice this
unexpected condition and tags the if branch with 'unlikely' as well.

I've actually once hit this BUG_ON() with some incorrect code changes
I had, which was very inconvenient as it required rebooting the VM.

Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 751a2761

fs/btrfs/ctree.c

+6 −1
Original line number Diff line number Diff line
@@ -4000,7 +4000,12 @@ static noinline int split_item(struct btrfs_path *path, 
	struct btrfs_disk_key disk_key;



	leaf = path->nodes[0];

	BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item));

	/*

	 * Shouldn't happen because the caller must have previously called

	 * setup_leaf_for_split() to make room for the new item in the leaf.

	 */

	if (WARN_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item)))

		return -ENOSPC;



	orig_slot = path->slots[0];

	orig_offset = btrfs_item_offset(leaf, path->slots[0]);