1 files changed, 24 insertions, 12 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 60794658ffd8..e390451c72e6 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -16,6 +16,7 @@
  * Boston, MA 021110-1307, USA.
  */
 #include <linux/sched.h>
+#include <linux/sched/signal.h>
 #include <linux/pagemap.h>
 #include <linux/writeback.h>
 #include <linux/blkdev.h>
@@ -130,6 +131,16 @@ void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 	if (atomic_dec_and_test(&cache->count)) {
 		WARN_ON(cache->pinned > 0);
 		WARN_ON(cache->reserved > 0);
+
+		/*
+		 * If not empty, someone is still holding mutex of
+		 * full_stripe_lock, which can only be released by caller.
+		 * And it will definitely cause use-after-free when caller
+		 * tries to release full stripe lock.
+		 *
+		 * No better way to resolve, but only to warn.
+		 */
+		WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 		kfree(cache->free_space_ctl);
 		kfree(cache);
 	}
@@ -315,14 +326,14 @@ get_caching_control(struct btrfs_block_group_cache *cache)
 	}
 
 	ctl = cache->caching_ctl;
-	atomic_inc(&ctl->count);
+	refcount_inc(&ctl->count);
 	spin_unlock(&cache->lock);
 	return ctl;
 }
 
 static void put_caching_control(struct btrfs_caching_control *ctl)
 {
-	if (atomic_dec_and_test(&ctl->count))
+	if (refcount_dec_and_test(&ctl->count))
 		kfree(ctl);
 }
 
@@ -598,7 +609,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 	init_waitqueue_head(&caching_ctl->wait);
 	caching_ctl->block_group = cache;
 	caching_ctl->progress = cache->key.objectid;
-	atomic_set(&caching_ctl->count, 1);
+	refcount_set(&caching_ctl->count, 1);
 	btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 			caching_thread, NULL, NULL);
 
@@ -619,7 +630,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 		struct btrfs_caching_control *ctl;
 
 		ctl = cache->caching_ctl;
-		atomic_inc(&ctl->count);
+		refcount_inc(&ctl->count);
 		prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 		spin_unlock(&cache->lock);
 
@@ -706,7 +717,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache,
 	}
 
 	down_write(&fs_info->commit_root_sem);
-	atomic_inc(&caching_ctl->count);
+	refcount_inc(&caching_ctl->count);
 	list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 	up_write(&fs_info->commit_root_sem);
 
@@ -891,7 +902,7 @@ search_again:
 	head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 	if (head) {
 		if (!mutex_trylock(&head->mutex)) {
-			atomic_inc(&head->node.refs);
+			refcount_inc(&head->node.refs);
 			spin_unlock(&delayed_refs->lock);
 
 			btrfs_release_path(path);
@@ -2979,7 +2990,7 @@ again:
 				struct btrfs_delayed_ref_node *ref;
 
 				ref = &head->node;
-				atomic_inc(&ref->refs);
+				refcount_inc(&ref->refs);
 
 				spin_unlock(&delayed_refs->lock);
 				/*
@@ -3002,7 +3013,6 @@ again:
 		goto again;
 	}
 out:
-	assert_qgroups_uptodate(trans);
 	trans->can_flush_pending_bgs = can_flush_pending_bgs;
 	return 0;
 }
@@ -3056,7 +3066,7 @@ static noinline int check_delayed_ref(struct btrfs_root *root,
 	}
 
 	if (!mutex_trylock(&head->mutex)) {
-		atomic_inc(&head->node.refs);
+		refcount_inc(&head->node.refs);
 		spin_unlock(&delayed_refs->lock);
 
 		btrfs_release_path(path);
@@ -3442,7 +3452,8 @@ again:
 		/*
 		 * don't bother trying to write stuff out _if_
 		 * a) we're not cached,
-		 * b) we're with nospace_cache mount option.
+		 * b) we're with nospace_cache mount option,
+		 * c) we're with v2 space_cache (FREE_SPACE_TREE).
 		 */
 		dcs = BTRFS_DC_WRITTEN;
 		spin_unlock(&block_group->lock);
@@ -9916,6 +9927,7 @@ btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
 	btrfs_init_free_space_ctl(cache);
 	atomic_set(&cache->trimming, 0);
 	mutex_init(&cache->free_space_lock);
+	btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
 
 	return cache;
 }
@@ -10415,7 +10427,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 				    &fs_info->caching_block_groups, list)
 				if (ctl->block_group == block_group) {
 					caching_ctl = ctl;
-					atomic_inc(&caching_ctl->count);
+					refcount_inc(&caching_ctl->count);
 					break;
 				}
 		}
@@ -10849,7 +10861,7 @@ static int btrfs_trim_free_extents(struct btrfs_device *device,
 		spin_lock(&fs_info->trans_lock);
 		trans = fs_info->running_transaction;
 		if (trans)
-			atomic_inc(&trans->use_count);
+			refcount_inc(&trans->use_count);
 		spin_unlock(&fs_info->trans_lock);
 
 		ret = find_free_dev_extent_start(trans, device, minlen, start,