Support adding a spare to a live md array with external metadata.

i.e. extend the 'md/dev-XXX/slot' attribute so that you can
tell a device to fill an vacant slot in an and md array.

Signed-off-by: Neil Brown <neilb@suse.de>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3b5cd4e..5d6fac1 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1932,7 +1932,7 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                slot = -1;
        else if (e==buf || (*e && *e!= '\n'))
                return -EINVAL;
-       if (rdev->mddev->pers) {
+       if (rdev->mddev->pers && slot == -1) {
                /* Setting 'slot' on an active array requires also
                 * updating the 'rd%d' link, and communicating
                 * with the personality with ->hot_*_disk.
@@ -1940,8 +1940,6 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                 * 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 */
@@ -1955,6 +1953,44 @@ slot_store(mdk_rdev_t *rdev, const char *buf, size_t len)
                sysfs_remove_link(&rdev->mddev->kobj, nm);
                set_bit(MD_RECOVERY_NEEDED, &rdev->mddev->recovery);
                md_wakeup_thread(rdev->mddev->thread);
+       } else if (rdev->mddev->pers) {
+               mdk_rdev_t *rdev2;
+               struct list_head *tmp;
+               /* Activating a spare .. or possibly reactivating
+                * if we every get bitmaps working here.
+                */
+
+               if (rdev->raid_disk != -1)
+                       return -EBUSY;
+
+               if (rdev->mddev->pers->hot_add_disk == NULL)
+                       return -EINVAL;
+
+               rdev_for_each(rdev2, tmp, rdev->mddev)
+                       if (rdev2->raid_disk == slot)
+                               return -EEXIST;
+
+               rdev->raid_disk = slot;
+               if (test_bit(In_sync, &rdev->flags))
+                       rdev->saved_raid_disk = slot;
+               else
+                       rdev->saved_raid_disk = -1;
+               err = rdev->mddev->pers->
+                       hot_add_disk(rdev->mddev, rdev);
+               if (err != 1) {
+                       rdev->raid_disk = -1;
+                       if (err == 0)
+                               return -EEXIST;
+                       return err;
+               }
+               sprintf(nm, "rd%d", rdev->raid_disk);
+               if (sysfs_create_link(&rdev->mddev->kobj, &rdev->kobj, nm))
+                       printk(KERN_WARNING
+                              "md: cannot register "
+                              "%s for %s\n",
+                              nm, mdname(rdev->mddev));
+
+               /* don't wakeup anyone, leave that to userspace. */
        } else {
                if (slot >= rdev->mddev->raid_disks)
                        return -ENOSPC;

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index e968116..4a1d714 100644 (file)
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -284,10 +284,15 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
        int found = 0;
        int path;
        struct multipath_info *p;
+       int first = 0;
+       int last = mddev->raid_disks - 1;
+
+       if (rdev->raid_disk >= 0)
+               first = last = rdev->raid_disk;
 
        print_multipath_conf(conf);
 
-       for (path=0; path<mddev->raid_disks; path++) 
+       for (path = first; path <= last; path++)
                if ((p=conf->multipaths+path)->rdev == NULL) {
                        q = rdev->bdev->bd_disk->queue;
                        blk_queue_stack_limits(mddev->queue, q);

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index c610b94..d32fc55 100644 (file)
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1103,8 +1103,13 @@ static int raid1_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
        int found = 0;
        int mirror = 0;
        mirror_info_t *p;
+       int first = 0;
+       int last = mddev->raid_disks - 1;
 
-       for (mirror=0; mirror < mddev->raid_disks; mirror++)
+       if (rdev->raid_disk >= 0)
+               first = last = rdev->raid_disk;
+
+       for (mirror = first; mirror <= last; mirror++)
                if ( !(p=conf->mirrors+mirror)->rdev) {
 
                        blk_queue_stack_limits(mddev->queue,

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index a71277b..50ad8d2 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1116,6 +1116,8 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
        int found = 0;
        int mirror;
        mirror_info_t *p;
+       int first = 0;
+       int last = mddev->raid_disks - 1;
 
        if (mddev->recovery_cp < MaxSector)
                /* only hot-add to in-sync arrays, as recovery is
@@ -1125,12 +1127,16 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
        if (!enough(conf))
                return 0;
 
+       if (rdev->raid_disk)
+               first = last = rdev->raid_disk;
+
        if (rdev->saved_raid_disk >= 0 &&
+           rdev->saved_raid_disk >= first &&
            conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
                mirror = rdev->saved_raid_disk;
        else
-               mirror = 0;
-       for ( ; mirror < mddev->raid_disks; mirror++)
+               mirror = first;
+       for ( ; mirror <= last ; mirror++)
                if ( !(p=conf->mirrors+mirror)->rdev) {
 
                        blk_queue_stack_limits(mddev->queue,

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 214b441..002f33b 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4607,21 +4607,27 @@ static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
        int found = 0;
        int disk;
        struct disk_info *p;
+       int first = 0;
+       int last = conf->raid_disks - 1;
 
        if (mddev->degraded > conf->max_degraded)
                /* no point adding a device */
                return 0;
 
+       if (rdev->raid_disk >= 0)
+               first = last = rdev->raid_disk;
+
        /*
         * find the disk ... but prefer rdev->saved_raid_disk
         * if possible.
         */
        if (rdev->saved_raid_disk >= 0 &&
+           rdev->saved_raid_disk >= first &&
            conf->disks[rdev->saved_raid_disk].rdev == NULL)
                disk = rdev->saved_raid_disk;
        else
-               disk = 0;
-       for ( ; disk < conf->raid_disks; disk++)
+               disk = first;
+       for ( ; disk <= last ; disk++)
                if ((p=conf->disks + disk)->rdev == NULL) {
                        clear_bit(In_sync, &rdev->flags);
                        rdev->raid_disk = disk;