The use case is when it's possible to mount a Btrfs volume ro, but not rw. Example, a situation where # mount -o degraded /dev/sdb /mnt [ 71.064352] BTRFS info (device sdb): allowing degraded mounts [ 71.064812] BTRFS info (device sdb): enabling auto recovery [ 71.065210] BTRFS info (device sdb): disk space caching is enabled [ 71.072068] BTRFS warning (device sdb): devid 2 missing [ 71.097320] BTRFS: too many missing devices, writeable mount is not allowed [ 71.116616] BTRFS: open_ctree failed Yet this works: # mount -o degraded,ro /dev/sdb /mnt It would be great if it were possible to send/receive subvolumes to a different btrfs volume. Currently it's not possible because those subvols aren't ro, and because the mount is ro I can't make ro snapshots first. Chris Murphy-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
