Commit 28cb13f2 authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: don't BUG_ON() when 0 reference count at btrfs_lookup_extent_info() 



Instead of doing a BUG_ON() handle the error by returning -EUCLEAN,
aborting the transaction and logging an error message.

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 5c83b3be

fs/btrfs/extent-tree.c

+20 −4
Original line number Diff line number Diff line
@@ -164,9 +164,16 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, 


		ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);

		num_refs = btrfs_extent_refs(leaf, ei);

		if (unlikely(num_refs == 0)) {

			ret = -EUCLEAN;

			btrfs_err(fs_info,

		"unexpected zero reference count for extent item (%llu %u %llu)",

				  key.objectid, key.type, key.offset);

			btrfs_abort_transaction(trans, ret);

			goto out_free;

		}

		extent_flags = btrfs_extent_flags(leaf, ei);

		owner = btrfs_get_extent_owner_root(fs_info, leaf, path->slots[0]);

		BUG_ON(num_refs == 0);

	} else {

		num_refs = 0;

		extent_flags = 0;
@@ -193,10 +200,19 @@ int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans, 
			goto search_again;

		}

		spin_lock(&head->lock);

		if (head->extent_op && head->extent_op->update_flags)

		if (head->extent_op && head->extent_op->update_flags) {

			extent_flags |= head->extent_op->flags_to_set;

		else

			BUG_ON(num_refs == 0);

		} else if (unlikely(num_refs == 0)) {

			spin_unlock(&head->lock);

			mutex_unlock(&head->mutex);

			spin_unlock(&delayed_refs->lock);

			ret = -EUCLEAN;

			btrfs_err(fs_info,

			  "unexpected zero reference count for extent %llu (%s)",

				  bytenr, metadata ? "metadata" : "data");

			btrfs_abort_transaction(trans, ret);

			goto out_free;

		}



		num_refs += head->ref_mod;

		spin_unlock(&head->lock);