Btrfs-progs: introduce '-t' option into subvolume list command

index c6d9a18..d605871 100644
@@ -1334,6 +1334,25 @@ static void print_subvolume_column(struct root_info *subv,
 	}
 }
 
+static void print_single_volume_info_table(struct root_info *subv)
+{
+	int i;
+
+	for (i = 0; i < BTRFS_LIST_ALL; i++) {
+		if (!btrfs_list_columns[i].need_print)
+			continue;
+
+		print_subvolume_column(subv, i);
+
+		if (i != BTRFS_LIST_PATH)
+			printf("\t");
+
+		if (i == BTRFS_LIST_TOP_LEVEL)
+			printf("\t");
+	}
+	printf("\n");
+}
+
 static void print_single_volume_info_default(struct root_info *subv)
 {
 	int i;

@@ -1351,21 +1370,58 @@ static void print_single_volume_info_default(struct root_info *subv)
 	printf("\n");
 }
 
-static void print_all_volume_info_default(struct root_lookup *sorted_tree)
+static void print_all_volume_info_tab_head()
+{
+	int i;
+	int len;
+	char barrier[20];
+
+	for (i = 0; i < BTRFS_LIST_ALL; i++) {
+		if (btrfs_list_columns[i].need_print)
+			printf("%s\t", btrfs_list_columns[i].name);
+
+		if (i == BTRFS_LIST_ALL-1)
+			printf("\n");
+	}
+
+	for (i = 0; i < BTRFS_LIST_ALL; i++) {
+		memset(barrier, 0, sizeof(barrier));
+
+		if (btrfs_list_columns[i].need_print) {
+			len = strlen(btrfs_list_columns[i].name);
+			while (len--)
+				strcat(barrier, "-");
+
+			printf("%s\t", barrier);
+		}
+		if (i == BTRFS_LIST_ALL-1)
+			printf("\n");
+	}
+}
+
+static void print_all_volume_info(struct root_lookup *sorted_tree,
+				  int is_tab_result)
 {
 	struct rb_node *n;
 	struct root_info *entry;
 
+	if (is_tab_result)
+		print_all_volume_info_tab_head();
+
 	n = rb_first(&sorted_tree->root);
 	while (n) {
 		entry = rb_entry(n, struct root_info, sort_node);
-		print_single_volume_info_default(entry);
+		if (is_tab_result)
+			print_single_volume_info_table(entry);
+		else
+			print_single_volume_info_default(entry);
 		n = rb_next(n);
 	}
 }
 
 int btrfs_list_subvols(int fd, struct btrfs_list_filter_set *filter_set,
-		       struct btrfs_list_comparer_set *comp_set)
+		       struct btrfs_list_comparer_set *comp_set,
+		       int is_tab_result)
 {
 	struct root_lookup root_lookup;
 	struct root_lookup root_sort;

@@ -1389,7 +1445,7 @@ int btrfs_list_subvols(int fd, struct btrfs_list_filter_set *filter_set,
 	__filter_and_sort_subvol(&root_lookup, &root_sort, filter_set,
 				 comp_set);
 
-	print_all_volume_info_default(&root_sort);
+	print_all_volume_info(&root_sort, is_tab_result);
 	__free_all_subvolumn(&root_lookup);
 	return ret;
 }

index 26a5c17..9d3687e 100644
@@ -98,7 +98,8 @@ int btrfs_list_setup_comparer(struct btrfs_list_comparer_set **comp_set,
 			      int is_descending);
 
 int btrfs_list_subvols(int fd, struct btrfs_list_filter_set *filter_set,
-		       struct btrfs_list_comparer_set *comp_set);
+		       struct btrfs_list_comparer_set *comp_set,
+			int is_tab_result);
 int btrfs_list_find_updated_files(int fd, u64 root_id, u64 oldest_gen);
 int btrfs_list_get_default_subvolume(int fd, u64 *default_id);
 char *btrfs_list_path_for_root(int fd, u64 root);

index f5da022..8399e72 100644
@@ -260,12 +260,13 @@ static int cmd_subvol_delete(int argc, char **argv)
 }
 
 static const char * const cmd_subvol_list_usage[] = {
-	"btrfs subvolume list [-pur] [-s 0|1] [-g [+|-]value] [-c [+|-]value] "
+	"btrfs subvolume list [-purt] [-s 0|1] [-g [+|-]value] [-c [+|-]value] "
 	"[--sort=gen,ogen,rootid,path] <path>",
 	"List subvolumes (and snapshots)",
 	"",
 	"-p           print parent ID",
 	"-u           print the uuid of subvolumes (and snapshots)",
+	"-t           print the result as a table",
 	"-s value     list snapshots with generation in ascending/descending order",
 	"             (1: ascending, 0: descending)",
 	"-r           list readonly subvolumes (including snapshots)",

@@ -292,6 +293,7 @@ static int cmd_subvol_list(int argc, char **argv)
 	int order;
 	int c;
 	char *subvol;
+	int is_tab_result = 0;
 	struct option long_options[] = {
 		{"sort", 1, NULL, 'S'},
 		{0, 0, 0, 0}

@@ -303,7 +305,7 @@ static int cmd_subvol_list(int argc, char **argv)
 	optind = 1;
 	while(1) {
 		c = getopt_long(argc, argv,
-				    "ps:urg:c:", long_options, NULL);
+				    "ps:urg:c:t", long_options, NULL);
 		if (c < 0)
 			break;
 

@@ -311,6 +313,9 @@ static int cmd_subvol_list(int argc, char **argv)
 		case 'p':
 			btrfs_list_setup_print_column(BTRFS_LIST_PARENT);
 			break;
+		case 't':
+			is_tab_result = 1;
+			break;
 		case 's':
 			order = atoi(optarg);
 			btrfs_list_setup_filter(&filter_set,

@@ -382,7 +387,8 @@ static int cmd_subvol_list(int argc, char **argv)
 		return 12;
 	}
 
-	ret = btrfs_list_subvols(fd, filter_set, comparer_set);
+	ret = btrfs_list_subvols(fd, filter_set, comparer_set,
+				is_tab_result);
 	if (ret)
 		return 19;
 	return 0;

@@ -588,7 +594,7 @@ static int cmd_subvol_get_default(int argc, char **argv)
 	btrfs_list_setup_filter(&filter_set, BTRFS_LIST_FILTER_ROOTID,
 				default_id);
 
-	ret = btrfs_list_subvols(fd, filter_set, NULL);
+	ret = btrfs_list_subvols(fd, filter_set, NULL, 0);
 	if (ret)
 		return 19;
 	return 0;