btrfs: add wrapper for transaction abort predicate

The status of aborted transaction can change between calls and it needs
to be accessed by READ_ONCE. Add a helper that also wraps the unlikely
hint.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2b4c3ca..da3d9ea 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1583,7 +1583,7 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
 	int err = 0;
 	int metadata = !extent_op->is_data;
 
-	if (trans->aborted)
+	if (TRANS_ABORTED(trans))
 		return 0;
 
 	if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
@@ -1703,7 +1703,7 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
 {
 	int ret = 0;
 
-	if (trans->aborted) {
+	if (TRANS_ABORTED(trans)) {
 		if (insert_reserved)
 			btrfs_pin_extent(trans->fs_info, node->bytenr,
 					 node->num_bytes, 1);
@@ -2191,7 +2191,7 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 	int run_all = count == (unsigned long)-1;
 
 	/* We'll clean this up in btrfs_cleanup_transaction */
-	if (trans->aborted)
+	if (TRANS_ABORTED(trans))
 		return 0;
 
 	if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
@@ -2913,7 +2913,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
 	else
 		unpin = &fs_info->freed_extents[0];
 
-	while (!trans->aborted) {
+	while (!TRANS_ABORTED(trans)) {
 		struct extent_state *cached_state = NULL;
 
 		mutex_lock(&fs_info->unused_bg_unpin_mutex);
@@ -2950,7 +2950,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
 		u64 trimmed = 0;
 
 		ret = -EROFS;
-		if (!trans->aborted)
+		if (!TRANS_ABORTED(trans))
 			ret = btrfs_discard_extent(fs_info,
 						   block_group->start,
 						   block_group->length,