On 03/07/2017 07:59 AM, Goldwyn Rodrigues wrote: > Hi, > > I want to know if re-mounting the root filesystem read-only should > change subvolumes mounted as read-write to read-only as well? We do > allow mounting subvolumes RW _after_ the root filesystem is mounted RO. > > # mount /dev/vdb /mnt > # mount -o ro,subvol=svro /dev/vdb /mnt/svro > # mount -o rw,subvol=svrw /dev/vdb /mnt/svrw > # mount -o remount,ro /dev/vdb /mnt > # touch /mnt/f3 > touch: cannot touch '/mnt/f3': Read-only file system > > Changes subvolume to read-only as well. > # touch /mnt/svrw/f3 > touch: cannot touch '/mnt/svrw/f3': Read-only file system > > However, remount of subvol as RW after remount,ro of root works: > # mount -o remount,rw,subvol=svrw /dev/vdb /mnt/svrw > # touch /mnt/svrw/f3 > Just to add, if you remount any one subvolume to read-only, all subvolumes turn read-only. # mount /dev/vdb /mnt # mount -o subvol=svro /dev/vdb /mnt/svro # mount -o subvol=svrw /dev/vdb /mnt/svrw # mount | grep mnt /dev/vdb on /mnt type btrfs (rw,relatime,space_cache,subvolid=5,subvol=/) /dev/vdb on /mnt/svro type btrfs (rw,relatime,space_cache,subvolid=257,subvol=/svro) /dev/vdb on /mnt/svrw type btrfs (rw,relatime,space_cache,subvolid=258,subvol=/svrw) # mount -o remount,ro /dev/vdb /mnt/svro # mount | grep mnt /dev/vdb on /mnt type btrfs (ro,relatime,space_cache,subvolid=5,subvol=/) /dev/vdb on /mnt/svro type btrfs (ro,relatime,space_cache,subvolid=257,subvol=/svro) /dev/vdb on /mnt/svrw type btrfs (ro,relatime,space_cache,subvolid=258,subvol=/svrw) -- Goldwyn -- 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
