2 files changed, 8 insertions, 6 deletions

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index b922bebb29cc..35be6dbca5e8 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -747,10 +747,10 @@ int btrfs_cache_block_group(struct btrfs_block_group *cache, int load_cache_only
 	cache->has_caching_ctl = 1;
 	spin_unlock(&cache->lock);
 
-	down_write(&fs_info->commit_root_sem);
+	spin_lock(&fs_info->block_group_cache_lock);
 	refcount_inc(&caching_ctl->count);
 	list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
-	up_write(&fs_info->commit_root_sem);
+	spin_unlock(&fs_info->block_group_cache_lock);
 
 	btrfs_get_block_group(cache);
 
@@ -999,7 +999,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	if (block_group->cached == BTRFS_CACHE_STARTED)
 		btrfs_wait_block_group_cache_done(block_group);
 	if (block_group->has_caching_ctl) {
-		down_write(&fs_info->commit_root_sem);
+		spin_lock(&fs_info->block_group_cache_lock);
 		if (!caching_ctl) {
 			struct btrfs_caching_control *ctl;
 
@@ -1013,7 +1013,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 		}
 		if (caching_ctl)
 			list_del_init(&caching_ctl->list);
-		up_write(&fs_info->commit_root_sem);
+		spin_unlock(&fs_info->block_group_cache_lock);
 		if (caching_ctl) {
 			/* Once for the caching bgs list and once for us. */
 			btrfs_put_caching_control(caching_ctl);
@@ -3311,14 +3311,14 @@ int btrfs_free_block_groups(struct btrfs_fs_info *info)
 	struct btrfs_caching_control *caching_ctl;
 	struct rb_node *n;
 
-	down_write(&info->commit_root_sem);
+	spin_lock(&info->block_group_cache_lock);
 	while (!list_empty(&info->caching_block_groups)) {
 		caching_ctl = list_entry(info->caching_block_groups.next,
 					 struct btrfs_caching_control, list);
 		list_del(&caching_ctl->list);
 		btrfs_put_caching_control(caching_ctl);
 	}
-	up_write(&info->commit_root_sem);
+	spin_unlock(&info->block_group_cache_lock);
 
 	spin_lock(&info->unused_bgs_lock);
 	while (!list_empty(&info->unused_bgs)) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 89597ea57115..b671ea4d80e1 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -208,6 +208,7 @@ static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
 	 * the caching thread will re-start it's search from 3, and thus find
 	 * the hole from [4,6) to add to the free space cache.
 	 */
+	spin_lock(&fs_info->block_group_cache_lock);
 	list_for_each_entry_safe(caching_ctl, next,
 				 &fs_info->caching_block_groups, list) {
 		struct btrfs_block_group *cache = caching_ctl->block_group;
@@ -220,6 +221,7 @@ static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
 			cache->last_byte_to_unpin = caching_ctl->progress;
 		}
 	}
+	spin_unlock(&fs_info->block_group_cache_lock);
 	up_write(&fs_info->commit_root_sem);
 }