diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 7e607416755a880fef1a06d3a8a3482417c0b364..0b180708bf79d87a36c9dcc78bbd6d72772101df 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1171,6 +1171,7 @@ struct btrfs_space_info {
 	struct percpu_counter total_bytes_pinned;
 
 	struct list_head list;
+	/* Protected by the spinlock 'lock'. */
 	struct list_head ro_bgs;
 
 	struct rw_semaphore groups_sem;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 15116585e7142d3865d822828011ee1ac38f0519..a684086c3c8123702cc41caa4d4dfe085aa7db3b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9422,7 +9422,6 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	 * are still on the list after taking the semaphore
 	 */
 	list_del_init(&block_group->list);
-	list_del_init(&block_group->ro_list);
 	if (list_empty(&block_group->space_info->block_groups[index])) {
 		kobj = block_group->space_info->block_group_kobjs[index];
 		block_group->space_info->block_group_kobjs[index] = NULL;
@@ -9464,6 +9463,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 	btrfs_remove_free_space_cache(block_group);
 
 	spin_lock(&block_group->space_info->lock);
+	list_del_init(&block_group->ro_list);
 	block_group->space_info->total_bytes -= block_group->key.offset;
 	block_group->space_info->bytes_readonly -= block_group->key.offset;
 	block_group->space_info->disk_total -= block_group->key.offset * factor;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 4ebabd2371533788c496070122def464004328ac..790dbae3343c4f965eaa58e317c08d702ad0a7ff 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2190,7 +2190,7 @@ void btrfs_free_io_failure_record(struct inode *inode, u64 start, u64 end)
 
 		next = next_state(state);
 
-		failrec = (struct io_failure_record *)state->private;
+		failrec = (struct io_failure_record *)(unsigned long)state->private;
 		free_extent_state(state);
 		kfree(failrec);
 
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 9e1569ffbf6ea66f1324022db9f9aba559339c73..2f0fbc374e876f90ee1e07ecfe5704bd4021c570 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3053,7 +3053,7 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 
 	ppath = btrfs_alloc_path();
 	if (!ppath) {
-		btrfs_free_path(ppath);
+		btrfs_free_path(path);
 		return -ENOMEM;
 	}
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 60f7cbe815e9c88362a1680f8e4259f51ca6f019..6f49b2872a6454330bac0ef912be3d0152e2ef4f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1000,10 +1000,20 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
 			 */
 			if (fs_info->pending_changes == 0)
 				return 0;
+			/*
+			 * A non-blocking test if the fs is frozen. We must not
+			 * start a new transaction here otherwise a deadlock
+			 * happens. The pending operations are delayed to the
+			 * next commit after thawing.
+			 */
+			if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
+				__sb_end_write(sb, SB_FREEZE_WRITE);
+			else
+				return 0;
 			trans = btrfs_start_transaction(root, 0);
-		} else {
-			return PTR_ERR(trans);
 		}
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
 	}
 	return btrfs_commit_transaction(trans, root);
 }
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index a605d4e2f2bca98e14c430c31514588c1b7982f1..e88b59d13439690f15810359ee7be343ad86b7a9 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -2118,7 +2118,7 @@ void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
 	unsigned long prev;
 	unsigned long bit;
 
-	prev = cmpxchg(&fs_info->pending_changes, 0, 0);
+	prev = xchg(&fs_info->pending_changes, 0);
 	if (!prev)
 		return;