From: NeilBrown <neilb@cse.unsw.edu.au>
i.e. missing or failed drives are moved to the end of the list. The means
a 3 drive md array with the first drive missing can be shrunk to a two
drive array. Currently that isn't possible.
Also, the "last_used" device number might be out-of-range after the number
of devices is reduced, so we set it to 0.
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
drivers/md/raid1.c | 24 +++++++++++++++++++-----
1 files changed, 19 insertions(+), 5 deletions(-)
diff -puN drivers/md/raid1.c~md-cause-md-raid1-to-repack-working-devices-when-number-of-drives-is-changed drivers/md/raid1.c
--- 25/drivers/md/raid1.c~md-cause-md-raid1-to-repack-working-devices-when-number-of-drives-is-changed 2005-05-13 22:44:24.000000000 -0700
+++ 25-akpm/drivers/md/raid1.c 2005-05-13 22:44:24.000000000 -0700
@@ -1349,17 +1349,26 @@ static int raid1_reshape(mddev_t *mddev,
* We allocate a new r1bio_pool if we can.
* Then raise a device barrier and wait until all IO stops.
* Then resize conf->mirrors and swap in the new r1bio pool.
+ *
+ * At the same time, we "pack" the devices so that all the missing
+ * devices have the higher raid_disk numbers.
*/
mempool_t *newpool, *oldpool;
struct pool_info *newpoolinfo;
mirror_info_t *newmirrors;
conf_t *conf = mddev_to_conf(mddev);
+ int cnt;
- int d;
+ int d, d2;
- for (d= raid_disks; d < conf->raid_disks; d++)
- if (conf->mirrors[d].rdev)
+ if (raid_disks < conf->raid_disks) {
+ cnt=0;
+ for (d= 0; d < conf->raid_disks; d++)
+ if (conf->mirrors[d].rdev)
+ cnt++;
+ if (cnt > raid_disks)
return -EBUSY;
+ }
newpoolinfo = kmalloc(sizeof(*newpoolinfo), GFP_KERNEL);
if (!newpoolinfo)
@@ -1390,8 +1399,12 @@ static int raid1_reshape(mddev_t *mddev,
/* ok, everything is stopped */
oldpool = conf->r1bio_pool;
conf->r1bio_pool = newpool;
- for (d=0; d < raid_disks && d < conf->raid_disks; d++)
- newmirrors[d] = conf->mirrors[d];
+
+ for (d=d2=0; d < conf->raid_disks; d++)
+ if (conf->mirrors[d].rdev) {
+ conf->mirrors[d].rdev->raid_disk = d2;
+ newmirrors[d2++].rdev = conf->mirrors[d].rdev;
+ }
kfree(conf->mirrors);
conf->mirrors = newmirrors;
kfree(conf->poolinfo);
@@ -1400,6 +1413,7 @@ static int raid1_reshape(mddev_t *mddev,
mddev->degraded += (raid_disks - conf->raid_disks);
conf->raid_disks = mddev->raid_disks = raid_disks;
+ conf->last_used = 0; /* just make sure it is in-range */
spin_lock_irq(&conf->resync_lock);
conf->barrier--;
spin_unlock_irq(&conf->resync_lock);
_