btrfs-progs: qgroup assign: add option to schedule rescan

Previous patch detecs inconsistency and unconditionally triggers quota
rescan. This may not be always desired as it's a heavy metadata
operation. In case of batch assignments it's better to trigger the
rescan at the end.

Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/Documentation/btrfs-qgroup.asciidoc b/Documentation/btrfs-qgroup.asciidoc
index eadfe1c..cd7192c 100644 (file)
--- a/Documentation/btrfs-qgroup.asciidoc
+++ b/Documentation/btrfs-qgroup.asciidoc
@@ -36,9 +36,17 @@ will not be functional until qgroup '0/<subvolume id>' is created again.
 
 SUBCOMMAND
 ----------
-*assign* <src> <dst> <path>::
+*assign* [options] <src> <dst> <path>::
 Assign qgroup <src> as the child qgroup of <dst> in the btrfs filesystem
 identified by <path>.
++
+`Options`
++
+--rescan::::
+Automatically schedule quota rescan if the new qgroup assignment leads to
+quota inconsistency.
+--no-rescan::::
+Explicitly ask not to do a rescan.
 
 *create* <qgroupid> <path>::
 Create a subvolume quota group.

diff --git a/cmds-qgroup.c b/cmds-qgroup.c
index f2200b7..4a8b8d2 100644 (file)
--- a/cmds-qgroup.c
+++ b/cmds-qgroup.c
@@ -37,19 +37,40 @@ static int qgroup_assign(int assign, int argc, char **argv)
        int ret = 0;
        int fd;
        int e;
+       int rescan = 0;
        char *path;
        struct btrfs_ioctl_qgroup_assign_args args;
        DIR *dirstream = NULL;
 
-       if (check_argc_exact(argc, 4))
+       while (1) {
+               enum { GETOPT_VAL_RESCAN = 256 };
+               static const struct option long_options[] = {
+                       { "rescan", no_argument, NULL, GETOPT_VAL_RESCAN },
+                       { NULL, 0, NULL, 0 }
+               };
+               int c = getopt_long(argc, argv, "", long_options, NULL);
+
+               if (c < 0)
+                       break;
+               switch (c) {
+               case GETOPT_VAL_RESCAN:
+                       rescan = 1;
+                       break;
+               default:
+                       /* Usage printed by the caller */
+                       return -1;
+               }
+       }
+
+       if (check_argc_exact(argc - optind, 3))
                return -1;
 
        memset(&args, 0, sizeof(args));
        args.assign = assign;
-       args.src = parse_qgroupid(argv[1]);
-       args.dst = parse_qgroupid(argv[2]);
+       args.src = parse_qgroupid(argv[optind]);
+       args.dst = parse_qgroupid(argv[optind + 1]);
 
-       path = argv[3];
+       path = argv[optind + 2];
 
        /*
         * FIXME src should accept subvol path
@@ -82,14 +103,19 @@ static int qgroup_assign(int assign, int argc, char **argv)
         * INCONSISTENT bit.
         */
        if (ret > 0) {
-               struct btrfs_ioctl_quota_rescan_args args;
-
-               printf("Quota data changed, quota rescan scheduled\n");
-               memset(&args, 0, sizeof(args));
-               ret = ioctl(fd, BTRFS_IOC_QUOTA_RESCAN, &args);
-               if (ret < 0)
-                       fprintf(stderr, "ERROR: quota rescan failed: %s\n",
-                               strerror(errno));
+               if (rescan) {
+                       struct btrfs_ioctl_quota_rescan_args args;
+
+                       printf("Quota data changed, rescan scheduled\n");
+                       memset(&args, 0, sizeof(args));
+                       ret = ioctl(fd, BTRFS_IOC_QUOTA_RESCAN, &args);
+                       if (ret < 0)
+                               fprintf(stderr,
+                                       "ERROR: quota rescan failed: %s\n",
+                                       strerror(errno));
+               } else {
+                       printf("WARNING: quotas may be inconsistent, rescan needed\n");
+               }
        }
        close_file_or_dir(fd, dirstream);
        return ret;
@@ -179,8 +205,11 @@ static int parse_limit(const char *p, unsigned long long *s)
 }
 
 static const char * const cmd_qgroup_assign_usage[] = {
-       "btrfs qgroup assign <src> <dst> <path>",
+       "btrfs qgroup assign [options] <src> <dst> <path>",
        "Enable subvolume qgroup support for a filesystem.",
+       "",
+       "--rescan       schedule qutoa rescan if needed",
+       "--no-rescan    ",
        NULL
 };