md/raid10: If there is a spare and a want_replacement device, start replacement.

When attempting to add a spare to a RAID10 array, also consider
adding it as a replacement for a want_replacement device.

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

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 011827d..6e8aa21 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -419,6 +419,9 @@ static void raid10_end_write_request(struct bio *bio, int error)
                        md_error(rdev->mddev, rdev);
                else {
                        set_bit(WriteErrorSeen, &rdev->flags);
+                       if (!test_and_set_bit(WantReplacement, &rdev->flags))
+                               set_bit(MD_RECOVERY_NEEDED,
+                                       &rdev->mddev->recovery);
                        set_bit(R10BIO_WriteError, &r10_bio->state);
                        dec_rdev = 0;
                }
@@ -1481,8 +1484,25 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
                struct mirror_info *p = &conf->mirrors[mirror];
                if (p->recovery_disabled == mddev->recovery_disabled)
                        continue;
-               if (p->rdev)
-                       continue;
+               if (p->rdev) {
+                       if (!test_bit(WantReplacement, &p->rdev->flags) ||
+                           p->replacement != NULL)
+                               continue;
+                       clear_bit(In_sync, &rdev->flags);
+                       set_bit(Replacement, &rdev->flags);
+                       rdev->raid_disk = mirror;
+                       err = 0;
+                       disk_stack_limits(mddev->gendisk, rdev->bdev,
+                                         rdev->data_offset << 9);
+                       if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
+                               blk_queue_max_segments(mddev->queue, 1);
+                               blk_queue_segment_boundary(mddev->queue,
+                                                          PAGE_CACHE_SIZE - 1);
+                       }
+                       conf->fullsync = 1;
+                       rcu_assign_pointer(p->replacement, rdev);
+                       break;
+               }
 
                disk_stack_limits(mddev->gendisk, rdev->bdev,
                                  rdev->data_offset << 9);
@@ -1658,6 +1678,9 @@ static void end_sync_write(struct bio *bio, int error)
                        md_error(mddev, rdev);
                else {
                        set_bit(WriteErrorSeen, &rdev->flags);
+                       if (!test_and_set_bit(WantReplacement, &rdev->flags))
+                               set_bit(MD_RECOVERY_NEEDED,
+                                       &rdev->mddev->recovery);
                        set_bit(R10BIO_WriteError, &r10_bio->state);
                }
        } else if (is_badblock(rdev,
@@ -1852,8 +1875,13 @@ static void fix_recovery_read_error(struct r10bio *r10_bio)
                                          s << 9,
                                          bio->bi_io_vec[idx].bv_page,
                                          WRITE, false);
-                       if (!ok)
+                       if (!ok) {
                                set_bit(WriteErrorSeen, &rdev->flags);
+                               if (!test_and_set_bit(WantReplacement,
+                                                     &rdev->flags))
+                                       set_bit(MD_RECOVERY_NEEDED,
+                                               &rdev->mddev->recovery);
+                       }
                }
                if (!ok) {
                        /* We don't worry if we cannot set a bad block -
@@ -1971,8 +1999,12 @@ static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
        if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
                /* success */
                return 1;
-       if (rw == WRITE)
+       if (rw == WRITE) {
                set_bit(WriteErrorSeen, &rdev->flags);
+               if (!test_and_set_bit(WantReplacement, &rdev->flags))
+                       set_bit(MD_RECOVERY_NEEDED,
+                               &rdev->mddev->recovery);
+       }
        /* need to record an error - either for the block or the device */
        if (!rdev_set_badblocks(rdev, sector, sectors, 0))
                md_error(rdev->mddev, rdev);