btrfs-progs: make the device scan logic more clear

1. Use long option to replace the original strcmp() to parse
the "--all-devices".
2. the "int ret" is defined in 2 places, just define it once
and make the return pattern into "goto + single return".

This does not change the actual scan procedure and return values.
Just make it clear, the original seems a little confusing.

Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>

diff --git a/cmds-device.c b/cmds-device.c
index d8bdcf4..309b49e 100644 (file)
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -187,51 +187,67 @@ static int cmd_rm_dev(int argc, char **argv)
 }
 
 static const char * const cmd_scan_dev_usage[] = {
-       "btrfs device scan [<--all-devices>|<device> [<device>...]]",
+       "btrfs device scan [options] [<device> [<device>...]]",
        "Scan devices for a btrfs filesystem",
+       "-d|--all-devices    scan all devices under /dev",
        NULL
 };
 
 static int cmd_scan_dev(int argc, char **argv)
 {
-       int     i, fd, e;
-       int     where = BTRFS_SCAN_LBLKID;
-       int     devstart = 1;
+       int i, fd, e;
+       int where = BTRFS_SCAN_LBLKID;
+       int devstart = 1;
+       int all = 0;
+       int ret = 0;
 
-       if( argc > 1 && !strcmp(argv[1],"--all-devices")){
-               if (check_argc_max(argc, 2))
+       optind = 1;
+       while (1) {
+               int long_index;
+               static struct option long_options[] = {
+                       { "all-devices", no_argument, NULL, 'd'},
+                       { 0, 0, 0, 0 },
+               };
+               int c = getopt_long(argc, argv, "d", long_options,
+                                   &long_index);
+               if (c < 0)
+                       break;
+               switch (c) {
+               case 'd':
+                       where = BTRFS_SCAN_DEV;
+                       all = 1;
+                       break;
+               default:
                        usage(cmd_scan_dev_usage);
-
-               where = BTRFS_SCAN_DEV;
-               devstart += 1;
+               }
        }
 
-       if(argc<=devstart){
-               int ret;
+       if (all && check_argc_max(argc, 2))
+               usage(cmd_scan_dev_usage);
+
+       if (all || argc == 1) {
                printf("Scanning for Btrfs filesystems\n");
                ret = scan_for_btrfs(where, BTRFS_UPDATE_KERNEL);
-               if (ret){
+               if (ret)
                        fprintf(stderr, "ERROR: error %d while scanning\n", ret);
-                       return 1;
-               }
-               return 0;
+               goto out;
        }
 
        fd = open("/dev/btrfs-control", O_RDWR);
        if (fd < 0) {
                perror("failed to open /dev/btrfs-control");
-               return 1;
+               ret = 1;
+               goto out;
        }
 
        for( i = devstart ; i < argc ; i++ ){
                struct btrfs_ioctl_vol_args args;
-               int ret;
 
                if (!is_block_device(argv[i])) {
                        fprintf(stderr,
                                "ERROR: %s is not a block device\n", argv[i]);
-                       close(fd);
-                       return 1;
+                       ret = 1;
+                       goto close_out;
                }
                printf("Scanning for Btrfs filesystems in '%s'\n", argv[i]);
 
@@ -245,15 +261,16 @@ static int cmd_scan_dev(int argc, char **argv)
                e = errno;
 
                if( ret < 0 ){
-                       close(fd);
                        fprintf(stderr, "ERROR: unable to scan the device '%s' - %s\n",
                                argv[i], strerror(e));
-                       return 1;
+                       goto close_out;
                }
        }
 
+close_out:
        close(fd);
-       return 0;
+out:
+       return !!ret;
 }
 
 static const char * const cmd_ready_dev_usage[] = {