----- Original Message -----
> From: "NeilBrown" <neilb@xxxxxxx>
> To: "Xiao Ni" <xni@xxxxxxxxxx>
> Cc: linux-raid@xxxxxxxxxxxxxxx
> Sent: Wednesday, February 4, 2015 2:39:21 PM
> Subject: Re: Can't reshape raid0 to raid10
>
> On Mon, 29 Dec 2014 22:13:41 -0500 (EST) Xiao Ni <xni@xxxxxxxxxx> wrote:
>
> > Hi Neil
> >
> > When I try to reshape a raid0 to raid10, it'll fail like this:
> >
> > [root@dhcp-12-133 mdadm-3.3.2]# lsblk
> > NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
> > sda 8:0 0 111.8G 0 disk
> > ├─sda1 8:1 0 1000M 0 part /boot
> > ├─sda2 8:2 0 29.3G 0 part /
> > ├─sda3 8:3 0 512M 0 part [SWAP]
> > ├─sda4 8:4 0 1K 0 part
> > ├─sda5 8:5 0 102M 0 part
> > └─sda6 8:6 0 10.1G 0 part
> > └─VolGroup00-LogVol00 254:0 0 9.9G 0 lvm
> > sdb 8:16 0 111.8G 0 disk
> > ├─sdb1 8:17 0 2G 0 part
> > └─sdb2 8:18 0 10G 0 part
> > sdc 8:32 0 186.3G 0 disk
> > ├─sdc1 8:33 0 2G 0 part
> > └─sdc2 8:34 0 10G 0 part
> > sdd 8:48 0 111.8G 0 disk
> > ├─sdd1 8:49 0 2G 0 part
> > └─sdd2 8:50 0 10G 0 part
> > [root@dhcp-12-133 mdadm-3.3.2]# mdadm -CR /dev/md0 -l0 -n3 /dev/sdb1
> > /dev/sdc1 /dev/sdd1
> > mdadm: Defaulting to version 1.2 metadata
> > mdadm: array /dev/md0 started.
> > [root@dhcp-12-133 mdadm-3.3.2]# mdadm --grow /dev/md0 -l10 -a /dev/sdb2
> > /dev/sdc2 /dev/sdd2
> > mdadm: level of /dev/md0 changed to raid10
> > mdadm: add new device failed for /dev/sdb2 as 6: No space left on device
> >
> >
> > But if I reshape the raid0 to raid5, reshape raid5 to raid0, then
> > reshape raid0 to raid10 use
> > the same command it'll succeed.
> >
> > [root@dhcp-12-133 mdadm-3.3.2]# mdadm -CR /dev/md0 -l0 -n3 /dev/sdb1
> > /dev/sdc1 /dev/sdd1
> > [root@dhcp-12-133 mdadm-3.3.2]# mdadm --grow /dev/md0 -l5
> > [root@dhcp-12-133 mdadm-3.3.2]# cat /proc/mdstat
> > Personalities : [raid6] [raid5] [raid4] [raid0] [raid10]
> > md0 : active raid5 sdd1[2] sdc1[1] sdb1[0]
> > 6285312 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3]
> > [UUU_]
> >
> > unused devices: <none>
> >
> > [root@dhcp-12-133 mdadm-3.3.2]# mdadm --grow /dev/md0 -l0
> > [root@dhcp-12-133 mdadm-3.3.2]# cat /proc/mdstat
> > Personalities : [raid6] [raid5] [raid4] [raid0] [raid10]
> > md0 : active raid0 sdd1[2] sdc1[1] sdb1[0]
> > 6285312 blocks super 1.2 512k chunks
> >
> > unused devices: <none>
> > [root@dhcp-12-133 mdadm-3.3.2]# mdadm --grow /dev/md0 -l10 -a /dev/sdb2
> > /dev/sdc2 /dev/sdd2
> > mdadm: level of /dev/md0 changed to raid10
> > mdadm: added /dev/sdb2
> > mdadm: added /dev/sdc2
> > mdadm: added /dev/sdd2
> >
> > So I guess it's the problem add the disk to raid10 after the reshaping.
> > In the function
> > super_1_validate, it'll set the mddev->dev_sectors using the superblock
> > read from disks.
> > If it's raid0, the le64_to_cpu(sb-size) is 0. So when add disk to raid10
> > bind_rdev_to_array
> > return -ENOSPC.
> >
> > When create raid0, it doesn't write give the value to s->size. So the
> > sb-size is 0.
> > I modify the code about Create.c. I'm not sure whether it's right to do so.
> > But it can resolve
> > the problem.
>
> Thanks for the report.
>
> I think this need to be fixing in the md driver, when the reshape happens.
>
> Something like the following.
>
> NeilBrown
>
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index d1203cddb024..b8d76b1fba64 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -3872,7 +3872,7 @@ static int raid10_resize(struct mddev *mddev, sector_t
> sectors)
> return 0;
> }
>
> -static void *raid10_takeover_raid0(struct mddev *mddev)
> +static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int
> devs)
> {
> struct md_rdev *rdev;
> struct r10conf *conf;
> @@ -3882,6 +3882,7 @@ static void *raid10_takeover_raid0(struct mddev *mddev)
> mdname(mddev));
> return ERR_PTR(-EINVAL);
> }
> + sector_div(size, devs);
>
> /* Set new parameters */
> mddev->new_level = 10;
> @@ -3892,12 +3893,15 @@ static void *raid10_takeover_raid0(struct mddev
> *mddev)
> mddev->raid_disks *= 2;
> /* make sure it will be not marked as dirty */
> mddev->recovery_cp = MaxSector;
> + mddev->dev_sectors = size;
>
> conf = setup_conf(mddev);
> if (!IS_ERR(conf)) {
> rdev_for_each(rdev, mddev)
> - if (rdev->raid_disk >= 0)
> + if (rdev->raid_disk >= 0) {
> rdev->new_raid_disk = rdev->raid_disk * 2;
> + rdev->sectors = size;
> + }
> conf->barrier = 1;
> }
>
> @@ -3920,7 +3924,9 @@ static void *raid10_takeover(struct mddev *mddev)
> mdname(mddev));
> return ERR_PTR(-EINVAL);
> }
> - return raid10_takeover_raid0(mddev);
> + return raid10_takeover_raid0(mddev,
> + raid0_conf->strip_zone->zone_end,
> + raid0_conf->strip_zone->nb_dev);
> }
> return ERR_PTR(-EINVAL);
> }
>
Thanks, the problem is fixed.
Best Regards
Xiao
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
