[PATCH] btrfs-progs: drop unique uuid test for btrfstune -M

[Anand Jain <anand.jain@oracle.com>]

It's common to copy/snapshot an OS image to run another instance of the OS.
A duplicate fsid can't be mounted on the same system unless the fsid is
changed by using btrfstune -m.

However in some circumstances the image needs to go back to the original
fsid /metadata_uuid.

As of now btrfstune -M fails if the specified uuid isn't unique, as show
below.

btrfstune -M $(btrfs in dump-super ./2-2g.img | grep metadata_uuid | \
					awk '{print $2}') ./2-2g.img
ERROR: fsid 87f8d9c5-a8b7-438e-a890-17bbe11c95e5 is not unique

But as we are changing the fsid of an unmounted image, so its ok to
leave it to the users choice if the fsid is not unique, so that the
image can be sent back the system where it was used with that fsid.

So this patch drops the check test_uuid_unique() for btrfstune -M|m.
Thanks.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 btrfstune.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/btrfstune.c b/btrfstune.c
index afa3aae35412..4befcadef8b1 100644
--- a/btrfstune.c
+++ b/btrfstune.c
@@ -570,10 +570,6 @@ int BOX_MAIN(btrfstune)(int argc, char *argv[])
 			error("could not parse UUID: %s", new_fsid_str);
 			return 1;
 		}
-		if (!test_uuid_unique(new_fsid_str)) {
-			error("fsid %s is not unique", new_fsid_str);
-			return 1;
-		}
 	}
 
 	fd = open(device, O_RDWR);
-- 
2.21.0 (Apple Git-120)