On Tuesday, April 17, 2012 4:53 AM NeilBrown wrote:
>
> On Fri, 13 Apr 2012 16:52:01 +0200 Adam Kwolek <adam.kwolek@xxxxxxxxx>
> wrote:
>
> > For raid0, takeover operation is required for size change.
> > Add takeover to degraded raid4 before size change and back to raid0 after.
> > Array information has to be read again from md after takeover.
> >
> > Signed-off-by: Adam Kwolek <adam.kwolek@xxxxxxxxx>
> > ---
> > Grow.c | 35 +++++++++++++++++++++++++++++++++++
> > 1 files changed, 35 insertions(+), 0 deletions(-)
> >
> > diff --git a/Grow.c b/Grow.c
> > index 8c7bafc..e8f6554 100644
> > --- a/Grow.c
> > +++ b/Grow.c
> > @@ -1626,6 +1626,7 @@ int Grow_reshape(char *devname, int fd, int
> quiet, char *backup_file,
> > long long orig_size = get_component_size(fd)/2;
> > long long min_csize;
> > struct mdinfo *mdi;
> > + int raid0_takeover = 0;
> >
> > if (orig_size == 0)
> > orig_size = array.size;
> > @@ -1674,6 +1675,28 @@ int Grow_reshape(char *devname, int fd, int
> quiet, char *backup_file,
> > "2TB per device\n");
> > size = min_csize;
> > }
> > + if (st->ss->external) {
> > + if (sra->array.level == 0) {
> > + rv = sysfs_set_str(sra, NULL, "level",
> > + "raid5");
> > + if (!rv) {
> > + raid0_takeover = 1;
> > + /* get array parametes after takeover
> > + * to chane one parameter at time
> only
> > + */
> > + rv = ioctl(fd, GET_ARRAY_INFO,
> &array);
> > + }
> > + }
> > + /* make sure mdmon is
> > + * aware of the new level */
> > + if (!mdmon_running(st->container_dev))
> > + start_mdmon(st->container_dev);
> > + ping_monitor(container);
> > + if (mdmon_running(st->container_dev) &&
> > + st->update_tail == NULL)
> > + st->update_tail = &st->updates;
> > + }
> > +
> > array.size = size;
> > if (array.size != size) {
> > /* got truncated to 32bit, write to
> > @@ -1686,12 +1709,24 @@ int Grow_reshape(char *devname, int fd, int
> quiet, char *backup_file,
> > rv = -1;
> > } else {
> > rv = ioctl(fd, SET_ARRAY_INFO, &array);
> > +
> > /* manage array size when it is managed externally
> > */
> > if ((rv == 0) && st->ss->external)
> > rv = set_array_size(st, sra, sra->text_version);
> > }
> >
> > + if (raid0_takeover) {
> > + /* do not recync non-existing parity,
> > + * we will drop it anyway
> > + */
> > + sysfs_set_str(sra, NULL, "sync_action", "idle");
>
> This is probably ineffective. If the array thinks it needs to resync, then
> just setting it to 'idle' will only stop in temporarily. It will immediately
> start syncing again.
>
> However given that it is a RAID5 array which is degraded, it shouldn't try to
> resync at all.
>
> So: does it still work if you remove this line? If so, could you send a
> patch to remove it?
> If not - we should work out why.
>
It doesn't work without this line.
The N-disks raid0 changes to degraded (N+1)-disks raid5 (N of N+1 disks)
in /proc/mdstat after size extension, however the metadata on all disks is correct.
Regards,
Lukasz
>
> > + /* go back to raid0, drop parity disk
> > + */
> > + sysfs_set_str(sra, NULL, "level", "raid0");
> > + ioctl(fd, GET_ARRAY_INFO, &array);
> > + }
> > +
> > if (rv != 0) {
> > int err = errno;
> >
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