btrfs-progs: btrfstune: add '-U' and '-u' option to change fsid

Add two options, '-U' and '-u' for btrfstune.

For '-u', it is used to change fsid to a random new UUID.
For '-U', it is used to change fsid to a specified UUID.

Both will also change the internal use only chunk_tree_uuid to a random
new UUID.

Although there is a GNU getopt extension "::" to get optional
option-argument, but is forbidden by POSIX.1-2008, so use split options
here.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

diff --git a/btrfstune.c b/btrfstune.c
index 9bf06c2..3324bbe 100644 (file)
--- a/btrfstune.c
+++ b/btrfstune.c
@@ -406,23 +406,28 @@ static void print_usage(void)
        fprintf(stderr, "\t-S value\tpositive value will enable seeding, zero to disable, negative is not allowed\n");
        fprintf(stderr, "\t-r \t\tenable extended inode refs\n");
        fprintf(stderr, "\t-x \t\tenable skinny metadata extent refs\n");
-       fprintf(stderr, "\t-f \t\tforce to set or clear flags, make sure that you are aware of the dangers\n");
+       fprintf(stderr, "\t-f \t\tforce to do dangerous operation, make sure that you are aware of the dangers\n");
+       fprintf(stderr, "\t-u \t\tchange fsid, use a random one\n");
+       fprintf(stderr, "\t-U UUID\t\tchange fsid to UUID\n");
 }
 
 int main(int argc, char *argv[])
 {
        struct btrfs_root *root;
+       enum btrfs_open_ctree_flags ctree_flags = OPEN_CTREE_WRITES;
        int success = 0;
        int total = 0;
        int extrefs_flag = 0;
        int seeding_flag = 0;
        u64 seeding_value = 0;
        int skinny_flag = 0;
+       int random_fsid = 0;
+       char *new_fsid_str = NULL;
        int ret;
 
        optind = 1;
        while(1) {
-               int c = getopt(argc, argv, "S:rxf");
+               int c = getopt(argc, argv, "S:rxfuU:");
                if (c < 0)
                        break;
                switch(c) {
@@ -439,6 +444,14 @@ int main(int argc, char *argv[])
                case 'f':
                        force = 1;
                        break;
+               case 'U':
+                       ctree_flags |= OPEN_CTREE_IGNORE_FSID_MISMATCH;
+                       new_fsid_str = optarg;
+                       break;
+               case 'u':
+                       ctree_flags |= OPEN_CTREE_IGNORE_FSID_MISMATCH;
+                       random_fsid = 1;
+                       break;
                default:
                        print_usage();
                        return 1;
@@ -453,13 +466,37 @@ int main(int argc, char *argv[])
                return 1;
        }
 
-       if (!(seeding_flag + extrefs_flag + skinny_flag)) {
+       if (random_fsid && new_fsid_str) {
+               fprintf(stderr,
+                       "ERROR: Random fsid can't be used with specified fsid\n");
+               return 1;
+       }
+       if (!(seeding_flag + extrefs_flag + skinny_flag) &&
+           !(random_fsid || new_fsid_str)) {
                fprintf(stderr,
                        "ERROR: At least one option should be assigned.\n");
                print_usage();
                return 1;
        }
 
+       if (new_fsid_str) {
+               uuid_t tmp;
+
+               ret = uuid_parse(new_fsid_str, tmp);
+               if (ret < 0) {
+                       fprintf(stderr,
+                               "ERROR: Could not parse UUID: %s\n",
+                               new_fsid_str);
+                       return 1;
+               }
+               if (!test_uuid_unique(new_fsid_str)) {
+                       fprintf(stderr,
+                               "ERROR: Fsid %s is not unique\n",
+                               new_fsid_str);
+                       return 1;
+               }
+       }
+
        ret = check_mounted(device);
        if (ret < 0) {
                fprintf(stderr, "Could not check mount status: %s\n",
@@ -470,7 +507,7 @@ int main(int argc, char *argv[])
                return 1;
        }
 
-       root = open_ctree(device, 0, OPEN_CTREE_WRITES);
+       root = open_ctree(device, 0, ctree_flags);
 
        if (!root) {
                fprintf(stderr, "Open ctree failed\n");
@@ -483,7 +520,8 @@ int main(int argc, char *argv[])
                        ret = ask_user("We are going to clear the seeding flag, are you sure?");
                        if (!ret) {
                                fprintf(stderr, "Clear seeding flag canceled\n");
-                               return 1;
+                               ret = 1;
+                               goto out;
                        }
                }
 
@@ -505,6 +543,25 @@ int main(int argc, char *argv[])
                total++;
        }
 
+       if (random_fsid || new_fsid_str) {
+               if (!force) {
+                       fprintf(stderr,
+                               "Warning: It's highly recommended to run 'btrfs check' before this operation\n");
+                       fprintf(stderr,
+                               "Also canceling running UUID change progress may cause corruption\n");
+                       ret = ask_user("We are going to change UUID, are your sure?");
+                       if (!ret) {
+                               fprintf(stderr, "UUID change canceled\n");
+                               ret = 1;
+                               goto out;
+                       }
+               }
+               ret = change_uuid(root->fs_info, new_fsid_str);
+               if (!ret)
+                       success++;
+               total++;
+       }
+
        if (success == total) {
                ret = 0;
        } else {
@@ -512,6 +569,7 @@ int main(int argc, char *argv[])
                ret = 1;
                fprintf(stderr, "btrfstune failed\n");
        }
+out:
        close_ctree(root);
 
        return ret;