md/raid5: recognise replacements when assembling array.

If a Replacement is seen, file it as such.

If we see two replacements (or two normal devices) for the one slot,
abort.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 31 insertions, 6 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index b443cd2459df..c80f8c2471cc 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4847,7 +4847,15 @@ static struct r5conf *setup_conf(struct mddev *mddev)
                         continue;
                 disk = conf->disks + raid_disk;
 
-                disk->rdev = rdev;
+                if (test_bit(Replacement, &rdev->flags)) {
+                        if (disk->replacement)
+                                goto abort;
+                        disk->replacement = rdev;
+                } else {
+                        if (disk->rdev)
+                                goto abort;
+                        disk->rdev = rdev;
+                }
 
                 if (test_bit(In_sync, &rdev->flags)) {
                         char b[BDEVNAME_SIZE];
@@ -4936,6 +4944,7 @@ static int run(struct mddev *mddev)
         int dirty_parity_disks = 0;
         struct md_rdev *rdev;
         sector_t reshape_offset = 0;
+        int i;
 
         if (mddev->recovery_cp != MaxSector)
                 printk(KERN_NOTICE "md/raid:%s: not clean"
@@ -5025,12 +5034,25 @@ static int run(struct mddev *mddev)
         conf->thread = NULL;
         mddev->private = conf;
 
-        /*
-         * 0 for a fully functional array, 1 or 2 for a degraded array.
-         */
-        list_for_each_entry(rdev, &mddev->disks, same_set) {
-                if (rdev->raid_disk < 0)
+        for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
+             i++) {
+                rdev = conf->disks[i].rdev;
+                if (!rdev && conf->disks[i].replacement) {
+                        /* The replacement is all we have yet */
+                        rdev = conf->disks[i].replacement;
+                        conf->disks[i].replacement = NULL;
+                        clear_bit(Replacement, &rdev->flags);
+                        conf->disks[i].rdev = rdev;
+                }
+                if (!rdev)
                         continue;
+                if (conf->disks[i].replacement &&
+                    conf->reshape_progress != MaxSector) {
+                        /* replacements and reshape simply do not mix. */
+                        printk(KERN_ERR "md: cannot handle concurrent "
+                               "replacement and reshape.\n");
+                        goto abort;
+                }
                 if (test_bit(In_sync, &rdev->flags)) {
                         working_disks++;
                         continue;
@@ -5064,6 +5086,9 @@ static int run(struct mddev *mddev)
                 dirty_parity_disks++;
         }
 
+        /*
+         * 0 for a fully functional array, 1 or 2 for a degraded array.
+         */
         mddev->degraded = calc_degraded(conf);
 
         if (has_failed(conf)) {