btrfs: simplify error detection flow during log replay

We have this fuzzy logic at btrfs_recover_log_trees() where we don't
abort the transaction and exit immediately after each function call that
returned an error, and instead have if-then-else logic or check if the
previous function call returned success before calling the next function.

Make the flow more straightforward by immediately aborting the transaction
and exiting after each function call failure. This also allows to avoid
two consecutive if statements that test the same conditions:

   if (!ret && wc.stage == LOG_WALK_REPLAY_ALL) {
        (...)
   }

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 29 insertions, 24 deletions

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index e52e15d46114..cc384f78dd21 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -7192,8 +7192,6 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
 	struct btrfs_path *path;
 	struct btrfs_trans_handle *trans;
 	struct btrfs_key key;
-	struct btrfs_key found_key;
-	struct btrfs_root *log;
 	struct btrfs_fs_info *fs_info = log_root_tree->fs_info;
 	struct walk_control wc = {
 		.process_func = process_one_buffer,
@@ -7227,6 +7225,9 @@ again:
 	key.offset = (u64)-1;
 
 	while (1) {
+		struct btrfs_root *log;
+		struct btrfs_key found_key;
+
 		ret = btrfs_search_slot(NULL, log_root_tree, &key, path, 0, 0);
 
 		if (ret < 0) {
@@ -7255,6 +7256,7 @@ again:
 						   true);
 		if (IS_ERR(wc.replay_dest)) {
 			ret = PTR_ERR(wc.replay_dest);
+			wc.replay_dest = NULL;
 			if (ret != -ENOENT) {
 				btrfs_put_root(log);
 				btrfs_abort_transaction(trans, ret);
@@ -7273,35 +7275,35 @@ again:
 			 * each subsequent pass.
 			 */
 			ret = btrfs_pin_extent_for_log_replay(trans, log->node);
-			btrfs_put_root(log);
-
-			if (!ret)
-				goto next;
-			btrfs_abort_transaction(trans, ret);
-			goto error;
+			if (ret) {
+				btrfs_put_root(log);
+				btrfs_abort_transaction(trans, ret);
+				goto error;
+			}
+			goto next;
 		}
 
 		wc.replay_dest->log_root = log;
 		ret = btrfs_record_root_in_trans(trans, wc.replay_dest);
 		if (ret) {
-			/* The loop needs to continue due to the root refs */
 			btrfs_abort_transaction(trans, ret);
-		} else {
-			ret = walk_log_tree(trans, log, &wc);
-			if (ret)
-				btrfs_abort_transaction(trans, ret);
+			goto next;
 		}
 
-		if (!ret && wc.stage == LOG_WALK_REPLAY_ALL) {
-			ret = fixup_inode_link_counts(trans, wc.replay_dest,
-						      path);
-			if (ret)
-				btrfs_abort_transaction(trans, ret);
+		ret = walk_log_tree(trans, log, &wc);
+		if (ret) {
+			btrfs_abort_transaction(trans, ret);
+			goto next;
 		}
 
-		if (!ret && wc.stage == LOG_WALK_REPLAY_ALL) {
+		if (wc.stage == LOG_WALK_REPLAY_ALL) {
 			struct btrfs_root *root = wc.replay_dest;
 
+			ret = fixup_inode_link_counts(trans, wc.replay_dest, path);
+			if (ret) {
+				btrfs_abort_transaction(trans, ret);
+				goto next;
+			}
 			/*
 			 * We have just replayed everything, and the highest
 			 * objectid of fs roots probably has changed in case
@@ -7311,17 +7313,20 @@ again:
 			 * could only happen during mount.
 			 */
 			ret = btrfs_init_root_free_objectid(root);
-			if (ret)
+			if (ret) {
 				btrfs_abort_transaction(trans, ret);
+				goto next;
+			}
+		}
+next:
+		if (wc.replay_dest) {
+			wc.replay_dest->log_root = NULL;
+			btrfs_put_root(wc.replay_dest);
 		}
-
-		wc.replay_dest->log_root = NULL;
-		btrfs_put_root(wc.replay_dest);
 		btrfs_put_root(log);
 
 		if (ret)
 			goto error;
-next:
 		if (found_key.offset == 0)
 			break;
 		key.offset = found_key.offset - 1;