Btrfs-progs: introduce -g -c --sort options into btrfs subvol list command

This patch introduces '-g' '-c' '--sort' options

The option '-g' can help you filter the subvolumes by the generation, you may
use it just like:

	btrfs subvol list -g +/-value <path>

'+' means the generation of the subvolumes should >= the value you specified.
'-' means the generation should <= the value
If you don't input either '+' nor '-', this command will list the subvolumes
that their generation equals to the value.

However if you want to find gengeration between value1 and value2
you may use the above like:

        btrfs sub list -g -value1 -g +value2 <path>

The option '-c' can help you filter the subvolumes by the ogeneration, you may
use it just like:

	btrfs subvol list -c +/-value <path>

The usage is the same to '-g'

You might want to list subvolumes in order of some items, such as root id, gen
and so on, you can use '--sort'. Now you can sort the subvolumes by root id,
gen, ogen and path.

For example:
If you want to list subvolumes in order of rootid, you can use the option like
that:

	btrfs sub list --sort=+/-rooid <path>

Here, '+' means the result is sorted by ascending order. '-' is by descending
order. If you don't specify either '+' nor '-', the result is sorted by
default - ascending order.

If you want to combine sort items, you do it like that:

	btrfs sub list --sort=-rootid,+path,ogen,gen <path>

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>

1 files changed, 46 insertions, 4 deletions

diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index f385816f..f5da022f 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -23,6 +23,7 @@
 #include <sys/stat.h>
 #include <libgen.h>
 #include <limits.h>
+#include <getopt.h>
 
 #include "kerncompat.h"
 #include "ioctl.h"
@@ -259,7 +260,8 @@ static int cmd_subvol_delete(int argc, char **argv)
 }
 
 static const char * const cmd_subvol_list_usage[] = {
-	"btrfs subvolume list [-pur] [-s 0|1] <path>",
+	"btrfs subvolume list [-pur] [-s 0|1] [-g [+|-]value] [-c [+|-]value] "
+	"[--sort=gen,ogen,rootid,path] <path>",
 	"List subvolumes (and snapshots)",
 	"",
 	"-p           print parent ID",
@@ -267,7 +269,17 @@ static const char * const cmd_subvol_list_usage[] = {
 	"-s value     list snapshots with generation in ascending/descending order",
 	"             (1: ascending, 0: descending)",
 	"-r           list readonly subvolumes (including snapshots)",
-	NULL
+	"-g [+|-]value",
+	"             filter the subvolumes by generation",
+	"             (+value: >= value; -value: <= value; value: = value)",
+	"-c [+|-]value",
+	"             filter the subvolumes by ogeneration",
+	"             (+value: >= value; -value: <= value; value: = value)",
+	"--sort=gen,ogen,rootid,path",
+	"             list the subvolume in order of gen, ogen, rootid or path",
+	"             you also can add '+' or '-' in front of each items.",
+	"             (+:ascending, -:descending, ascending default)",
+	NULL,
 };
 
 static int cmd_subvol_list(int argc, char **argv)
@@ -278,14 +290,20 @@ static int cmd_subvol_list(int argc, char **argv)
 	int fd;
 	int ret;
 	int order;
+	int c;
 	char *subvol;
+	struct option long_options[] = {
+		{"sort", 1, NULL, 'S'},
+		{0, 0, 0, 0}
+	};
 
 	filter_set = btrfs_list_alloc_filter_set();
 	comparer_set = btrfs_list_alloc_comparer_set();
 
 	optind = 1;
 	while(1) {
-		int c = getopt(argc, argv, "ps:ur");
+		c = getopt_long(argc, argv,
+				    "ps:urg:c:", long_options, NULL);
 		if (c < 0)
 			break;
 
@@ -303,13 +321,37 @@ static int cmd_subvol_list(int argc, char **argv)
 						  !order);
 			btrfs_list_setup_print_column(BTRFS_LIST_OGENERATION);
 			btrfs_list_setup_print_column(BTRFS_LIST_OTIME);
-			break;
+
 		case 'u':
 			btrfs_list_setup_print_column(BTRFS_LIST_UUID);
 			break;
 		case 'r':
 			flags |= BTRFS_ROOT_SUBVOL_RDONLY;
 			break;
+		case 'g':
+			btrfs_list_setup_print_column(BTRFS_LIST_GENERATION);
+			ret = btrfs_list_parse_filter_string(optarg,
+							&filter_set,
+							BTRFS_LIST_FILTER_GEN);
+			if (ret)
+				usage(cmd_subvol_list_usage);
+			break;
+
+		case 'c':
+			btrfs_list_setup_print_column(BTRFS_LIST_OGENERATION);
+			ret = btrfs_list_parse_filter_string(optarg,
+							&filter_set,
+							BTRFS_LIST_FILTER_CGEN);
+			if (ret)
+				usage(cmd_subvol_list_usage);
+			break;
+		case 'S':
+			ret = btrfs_list_parse_sort_string(optarg,
+							   &comparer_set);
+			if (ret)
+				usage(cmd_subvol_list_usage);
+			break;
+
 		default:
 			usage(cmd_subvol_list_usage);
 		}