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Commit c303da6d authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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md: give userspace control over removing failed devices when external metdata in use 



When a device fails, we must not allow an further writes to the array until
the device failure has been recorded in array metadata.  When metadata is
managed externally, this requires some synchronisation...

Allow/require userspace to explicitly remove failed devices from active
service in the array by writing 'none' to the 'slot' attribute.  If this
reduces the number of failed devices to 0, the write block will automatically
be lowered.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e691063a

drivers/md/md.c

+34 −9
Original line number Diff line number Diff line
@@ -1891,20 +1891,44 @@ static ssize_t 
slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)

{

	char *e;

	int err;

	char nm[20];

	int slot = simple_strtoul(buf, &e, 10);

	if (strncmp(buf, "none", 4)==0)

		slot = -1;

	else if (e==buf || (*e && *e!= '\n'))

		return -EINVAL;

	if (rdev->mddev->pers)

		/* Cannot set slot in active array (yet) */

	if (rdev->mddev->pers) {

		/* Setting 'slot' on an active array requires also

		 * updating the 'rd%d' link, and communicating

		 * with the personality with ->hot_*_disk.

		 * For now we only support removing

		 * failed/spare devices.  This normally happens automatically,

		 * but not when the metadata is externally managed.

		 */

		if (slot != -1)

			return -EBUSY;

		if (rdev->raid_disk == -1)

			return -EEXIST;

		/* personality does all needed checks */

		if (rdev->mddev->pers->hot_add_disk == NULL)

			return -EINVAL;

		err = rdev->mddev->pers->

			hot_remove_disk(rdev->mddev, rdev->raid_disk);

		if (err)

			return err;

		sprintf(nm, "rd%d", rdev->raid_disk);

		sysfs_remove_link(&rdev->mddev->kobj, nm);

		set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);

		md_wakeup_thread(rdev->mddev->thread);

	} else {

		if (slot >= rdev->mddev->raid_disks)

			return -ENOSPC;

		rdev->raid_disk = slot;

		/* assume it is working */

		rdev->flags = 0;

		set_bit(In_sync, &rdev->flags);

	}

	return len;

}
@@ -5549,6 +5573,7 @@ static int remove_and_add_spares(mddev_t *mddev) 


	ITERATE_RDEV(mddev,rdev,rtmp)

		if (rdev->raid_disk >= 0 &&

		    !mddev->external &&

		    (test_bit(Faulty, &rdev->flags) ||

		     ! test_bit(In_sync, &rdev->flags)) &&

		    atomic_read(&rdev->nr_pending)==0) {