[PATCH/RFC] md/raid10: spread read for subordinate r10bios during recovery
From: Namhyung Kim <hidden>
Date: 2011-06-10 03:31:48
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
In the current scheme, multiple read request could be directed to the first active disk during recovery if there are several disk failure at the same time. Spreading those requests on other in-sync disks might be helpful. Signed-off-by: Namhyung Kim <redacted> --- drivers/md/raid10.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index dea73bdb99b8..d0188e49f881 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c@@ -1832,6 +1832,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) { /* recovery... the complicated one */ int j, k; + int last_read = -1; r10_bio = NULL; for (i=0 ; i<conf->raid_disks; i++) {
@@ -1891,7 +1892,9 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, &sync_blocks, still_degraded); for (j=0; j<conf->copies;j++) { - int d = r10_bio->devs[j].devnum; + int c = (last_read + j + 1) % conf->copies; + int d = r10_bio->devs[c].devnum; + if (!conf->mirrors[d].rdev || !test_bit(In_sync, &conf->mirrors[d].rdev->flags)) continue;
@@ -1902,13 +1905,14 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, bio->bi_private = r10_bio; bio->bi_end_io = end_sync_read; bio->bi_rw = READ; - bio->bi_sector = r10_bio->devs[j].addr + + bio->bi_sector = r10_bio->devs[c].addr + conf->mirrors[d].rdev->data_offset; bio->bi_bdev = conf->mirrors[d].rdev->bdev; atomic_inc(&conf->mirrors[d].rdev->nr_pending); atomic_inc(&r10_bio->remaining); - /* and we write to 'i' */ + last_read = c; + /* and we write to 'i' */ for (k=0; k<conf->copies; k++) if (r10_bio->devs[k].devnum == i) break;
--
1.7.5.2