btrfs-progs: Introduce change_uuid function

This function does all the needed things for changing filesystem uuid.

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 9a63f41..7b8090a 100644 (file)
--- a/btrfstune.c
+++ b/btrfstune.c
@@ -23,11 +23,14 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <dirent.h>
+#include <uuid/uuid.h>
+
 #include "kerncompat.h"
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
 #include "utils.h"
+#include "volumes.h"
 
 static char *device;
 static int force = 0;
@@ -290,6 +293,72 @@ static int change_fsid_done(struct btrfs_fs_info *fs_info)
        return write_all_supers(fs_info->tree_root);
 }
 
+static int change_uuid(struct btrfs_fs_info *fs_info, const char *new_fsid,
+                      const char *new_chunk_uuid)
+{
+       int ret = 0;
+
+       /* caller should do extra check on passed uuid */
+       if (new_fsid) {
+               /* allocated mem will be freed at close_ctree() */
+               fs_info->new_fsid = malloc(BTRFS_FSID_SIZE);
+               if (!fs_info->new_fsid) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               ret = uuid_parse(new_fsid, fs_info->new_fsid);
+               if (ret < 0)
+                       goto out;
+       }
+
+       if (new_chunk_uuid) {
+               /* allocated mem will be freed at close_ctree() */
+               fs_info->new_chunk_tree_uuid = malloc(BTRFS_UUID_SIZE);
+               if (!fs_info->new_chunk_tree_uuid) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               ret = uuid_parse(new_chunk_uuid, fs_info->new_chunk_tree_uuid);
+               if (ret < 0)
+                       goto out;
+       }
+
+       /* Now we can begin fsid change */
+       ret = change_fsid_prepare(fs_info);
+       if (ret < 0)
+               goto out;
+
+       /* Change extents first */
+       ret = change_extents_uuid(fs_info);
+       if (ret < 0) {
+               fprintf(stderr, "Failed to change UUID of metadata\n");
+               goto out;
+       }
+
+       /* Then devices */
+       ret = change_devices_uuid(fs_info);
+       if (ret < 0) {
+               fprintf(stderr, "Failed to change UUID of devices\n");
+               goto out;
+       }
+
+       /* Last, change fsid in super, only fsid change needs this */
+       if (new_fsid) {
+               memcpy(fs_info->fs_devices->fsid, fs_info->new_fsid,
+                      BTRFS_FSID_SIZE);
+               memcpy(fs_info->super_copy->fsid, fs_info->new_fsid,
+                      BTRFS_FSID_SIZE);
+               ret = write_all_supers(fs_info->tree_root);
+               if (ret < 0)
+                       goto out;
+       }
+
+       /* Now fsid change is done */
+       ret = change_fsid_done(fs_info);
+out:
+       return ret;
+}
+
 static void print_usage(void)
 {
        fprintf(stderr, "usage: btrfstune [options] device\n");