btrfs-progs: check/lowmem: fix false alerts about EXTENT_OWNER

[BUG]
When simple quota is enabled, lowmem will give false alerts:

 [3/8] checking extents
 ERROR: extent[13631488 168 1048576] has unknown ref type: 172
 ERROR: extent[63963136 168 131072] has unknown ref type: 172
 ERROR: extent[63963136 168 131072] has unknown ref type: 172
 ERROR: file extent[257 0] root 256 owner 256 backref lost
 ERROR: extent[13631488 168 1048576] has unknown ref type: 172
 ERROR: file extent[258 0] root 256 owner 256 backref lost
 ERROR: errors found in extent allocation tree or chunk allocation

[CAUSE]
Lowmem mode has strict checks on the inlined backref type, and
unfortunately EXTENT_OWNER_REF is not inside the support 4 backre types,
thus it's treated as an unknown type, and caused the false alerts.

[FIX]
Add the EXTENT_OWNER_REF type into the supported types.

For lowmem check itself, those key types are just skipped as it's only
to indicate the owner of a data extent, which will be verified by qgroup
part.

Signed-off-by: Qu Wenruo <wqu@suse.com>

Author: adam900710

check/mode-lowmem.c

@@ -3053,6 +3053,7 @@ static int check_extent_inline_ref(struct extent_buffer *eb,
 	case BTRFS_EXTENT_DATA_REF_KEY:
 	case BTRFS_SHARED_BLOCK_REF_KEY:
 	case BTRFS_SHARED_DATA_REF_KEY:
+	case BTRFS_EXTENT_OWNER_REF_KEY:
 		ret = 0;
 		break;
 	default:
@@ -4645,6 +4646,12 @@ static int check_extent_item(struct btrfs_path *path)
 		parent = offset;
 		tmp_err |= check_shared_data_backref(offset, key.objectid);
 		break;
+	case BTRFS_EXTENT_OWNER_REF_KEY:
+		/*
+		 * This is showing the initial owner for SIMPLE QUOTA.
+		 * It will be hanled by qgroup check, skip it here.
+		 */
+		break;
 	default:
 		error("extent[%llu %d %llu] has unknown ref type: %d",
 			key.objectid, key.type, key.offset, type);