Commit 13c2018f authored by Filipe Manana's avatar Filipe Manana Committed by David Sterba
Browse files

btrfs: assert proper locks are held at tree_insert_offset() 



There are multiple code paths leading to tree_insert_offset(), and each
path takes the necessary locks before tree_insert_offset() is called,
since they do other things that require those locks to be held. This makes
it easy to miss the locking somewhere, so make tree_insert_offset() assert
that the required locks are being held by the calling task.

Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 0d6bac4d

fs/btrfs/free-space-cache.c

+19 −6
Original line number Diff line number Diff line
@@ -1598,12 +1598,25 @@ static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl, 
	return bitmap_start;

}



static int tree_insert_offset(struct rb_root *root,

static int tree_insert_offset(struct btrfs_free_space_ctl *ctl,

			      struct btrfs_free_cluster *cluster,

			      struct btrfs_free_space *new_entry)

{

	struct rb_node **p = &root->rb_node;

	struct rb_root *root;

	struct rb_node **p;

	struct rb_node *parent = NULL;



	lockdep_assert_held(&ctl->tree_lock);



	if (cluster) {

		lockdep_assert_held(&cluster->lock);

		root = &cluster->root;

	} else {

		root = &ctl->free_space_offset;

	}



	p = &root->rb_node;



	while (*p) {

		struct btrfs_free_space *info;
@@ -1836,7 +1849,7 @@ static int link_free_space(struct btrfs_free_space_ctl *ctl, 
	int ret = 0;



	ASSERT(info->bytes || info->bitmap);

	ret = tree_insert_offset(&ctl->free_space_offset, info);

	ret = tree_insert_offset(ctl, NULL, info);

	if (ret)

		return ret;
@@ -3013,7 +3026,7 @@ static void __btrfs_return_cluster_to_free_space( 
					entry->bytes;

			}

		}

		tree_insert_offset(&ctl->free_space_offset, entry);

		tree_insert_offset(ctl, NULL, entry);

		rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes,

			      entry_less);

	}
@@ -3387,7 +3400,7 @@ static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group, 
	 */

	RB_CLEAR_NODE(&entry->bytes_index);



	ret = tree_insert_offset(&cluster->root, entry);

	ret = tree_insert_offset(ctl, cluster, entry);

	ASSERT(!ret); /* -EEXIST; Logic error */



	trace_btrfs_setup_cluster(block_group, cluster,
@@ -3477,7 +3490,7 @@ setup_cluster_no_bitmap(struct btrfs_block_group *block_group, 


		rb_erase(&entry->offset_index, &ctl->free_space_offset);

		rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);

		ret = tree_insert_offset(&cluster->root, entry);

		ret = tree_insert_offset(ctl, cluster, entry);

		total_size += entry->bytes;

		ASSERT(!ret); /* -EEXIST; Logic error */

	} while (node && entry != last);