[PATCH] btrfs-progs: cmds: subvolume: add -p option on creating subvol

[Sidong Yang <realwakka@gmail.com>]

This patch resolves github issue #429. This patch adds an option that
create parent directories when it creates subvolumes on nonexisting
parents. This option tokenizes dstdir and checks each paths whether
it's existing directory and make directory for creating subvolume.

Signed-off-by: Sidong Yang <realwakka@gmail.com>
---
 cmds/subvolume.c | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/cmds/subvolume.c b/cmds/subvolume.c
index fbf56566..1070c74a 100644
--- a/cmds/subvolume.c
+++ b/cmds/subvolume.c
@@ -88,6 +88,7 @@ static const char * const cmd_subvol_create_usage[] = {
 	"",
 	"-i <qgroupid>  add the newly created subvolume to a qgroup. This",
 	"               option can be given multiple times.",
+	"-p             make any missing parent directories for each argument",
 	HELPINFO_INSERT_GLOBALS,
 	HELPINFO_INSERT_QUIET,
 	NULL
@@ -105,10 +106,11 @@ static int cmd_subvol_create(const struct cmd_struct *cmd,
 	char	*dst;
 	struct btrfs_qgroup_inherit *inherit = NULL;
 	DIR	*dirstream = NULL;
+	bool create_parents = false;
 
 	optind = 0;
 	while (1) {
-		int c = getopt(argc, argv, "c:i:");
+		int c = getopt(argc, argv, "c:i:p");
 		if (c < 0)
 			break;
 
@@ -127,6 +129,9 @@ static int cmd_subvol_create(const struct cmd_struct *cmd,
 				goto out;
 			}
 			break;
+		case 'p':
+			create_parents = true;
+			break;
 		default:
 			usage_unknown_option(cmd, argv);
 		}
@@ -167,6 +172,30 @@ static int cmd_subvol_create(const struct cmd_struct *cmd,
 		goto out;
 	}
 
+	if (create_parents) {
+		char p[PATH_MAX];
+		char dstdir_real[PATH_MAX];
+		char *token;
+
+		realpath(dstdir, dstdir_real);
+		token = strtok(dstdir_real, "/");
+		while(token) {
+			strcat(p, "/");
+			strcat(p, token);
+			res = path_is_dir(p);
+			if (res == -ENOENT) {
+				if (mkdir(p, 0755)) {
+					error("failed to make dir: %s", p);
+					goto out;
+				}
+			} else if (res <= 0) {
+				error("failed to check dir: %s", p);				
+				goto out;
+			}
+			token = strtok(NULL, "/");
+		}
+	}
+
 	fddst = btrfs_open_dir(dstdir, &dirstream, 1);
 	if (fddst < 0)
 		goto out;
-- 
2.25.1