btrfs: rename ret to err in btrfs_recover_relocation()

In the function btrfs_recover_relocation(), currently the variable 'err'
carries the return value and 'ret' holds the intermediary return value.
However, in some lines, we don't need this two-step approach; we can
directly use 'err'. So, optimize them, which requires reinitializing 'err'
to zero at two locations.

This is a preparatory patch to fix the code style by renaming 'err'
to 'ret'.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/relocation.c

@@ -4233,17 +4233,16 @@ int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
 	key.offset = (u64)-1;
 
 	while (1) {
-		ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
+		err = btrfs_search_slot(NULL, fs_info->tree_root, &key,
 					path, 0, 0);
-		if (ret < 0) {
-			err = ret;
+		if (err < 0)
 			goto out;
-		}
-		if (ret > 0) {
+		if (err > 0) {
 			if (path->slots[0] == 0)
 				break;
 			path->slots[0]--;
 		}
+		err = 0;
 		leaf = path->nodes[0];
 		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 		btrfs_release_path(path);
@@ -4265,16 +4264,13 @@ int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
 			fs_root = btrfs_get_fs_root(fs_info,
 					reloc_root->root_key.offset, false);
 			if (IS_ERR(fs_root)) {
-				ret = PTR_ERR(fs_root);
-				if (ret != -ENOENT) {
-					err = ret;
+				err = PTR_ERR(fs_root);
+				if (err != -ENOENT)
 					goto out;
-				}
-				ret = mark_garbage_root(reloc_root);
-				if (ret < 0) {
-					err = ret;
+				err = mark_garbage_root(reloc_root);
+				if (err < 0)
 					goto out;
-				}
+				err = 0;
 			} else {
 				btrfs_put_root(fs_root);
 			}
@@ -4296,11 +4292,9 @@ int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
 		goto out;
 	}
 
-	ret = reloc_chunk_start(fs_info);
-	if (ret < 0) {
-		err = ret;
+	err = reloc_chunk_start(fs_info);
+	if (err < 0)
 		goto out_end;
-	}
 
 	rc->extent_root = btrfs_extent_root(fs_info, 0);