btrfs: convert block group refcount to refcount_t

We have refcount_t now with the associated library to handle refcounts,
which gives us extra debugging around reference count mistakes that may
be made.  For example it'll warn on any transition from 0->1 or 0->-1,
which is handy for noticing cases where we've messed up reference
counting.  Convert the block group ref counting from an atomic_t to
refcount_t and use the appropriate helpers.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 6ade9d345e660494ea4ea42eab2a5e3982cbbeb9..884de28a41e4ba4cafcd30100ae3399d465bd700 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -118,12 +118,12 @@ u64 btrfs_get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
 
 void btrfs_get_block_group(struct btrfs_block_group *cache)
 {
-       atomic_inc(&cache->count);
+       refcount_inc(&cache->refs);
 }
 
 void btrfs_put_block_group(struct btrfs_block_group *cache)
 {
-       if (atomic_dec_and_test(&cache->count)) {
+       if (refcount_dec_and_test(&cache->refs)) {
                WARN_ON(cache->pinned > 0);
                WARN_ON(cache->reserved > 0);
 
@@ -1805,7 +1805,7 @@ static struct btrfs_block_group *btrfs_create_block_group_cache(
 
        cache->discard_index = BTRFS_DISCARD_INDEX_UNUSED;
 
-       atomic_set(&cache->count, 1);
+       refcount_set(&cache->refs, 1);
        spin_lock_init(&cache->lock);
        init_rwsem(&cache->data_rwsem);
        INIT_LIST_HEAD(&cache->list);
@@ -3380,7 +3380,7 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
                ASSERT(list_empty(&block_group->dirty_list));
                ASSERT(list_empty(&block_group->io_list));
                ASSERT(list_empty(&block_group->bg_list));
-               ASSERT(atomic_read(&block_group->count) == 1);
+               ASSERT(refcount_read(&block_group->refs) == 1);
                btrfs_put_block_group(block_group);
 
                spin_lock(&info->block_group_cache_lock);

diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index b6ee70a039c70ca01f99479ff193cf3704243a07..adfd7583a17b80e074e7e6604ebca2fc65461ff9 100644 (file)
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -114,8 +114,7 @@ struct btrfs_block_group {
        /* For block groups in the same raid type */
        struct list_head list;
 
-       /* Usage count */
-       atomic_t count;
+       refcount_t refs;
 
        /*
         * List of struct btrfs_free_clusters for this block group.