diff options
author | NeilBrown <neilb@suse.de> | 2011-07-28 11:39:24 +1000 |
---|---|---|
committer | NeilBrown <neilb@suse.de> | 2011-07-28 11:39:24 +1000 |
commit | d4432c23be957ff061f7b23fd60e8506cb472a55 (patch) | |
tree | 1e9e8cbc75721e62300bb2251658de870bf79d8a | |
parent | e875ecea266a543e643b19e44cf472f1412708f9 (diff) |
md/raid10: avoid writing to known bad blocks on known bad drives.
Writing to known bad blocks on drives that have seen a write error
is asking for trouble. So try to avoid these blocks.
Signed-off-by: NeilBrown <neilb@suse.de>
-rw-r--r-- | drivers/md/raid10.c | 105 |
1 files changed, 93 insertions, 12 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index de608992627..13077a3fd7d 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -807,6 +807,8 @@ static int make_request(mddev_t *mddev, struct bio * bio) unsigned long flags; mdk_rdev_t *blocked_rdev; int plugged; + int sectors_handled; + int max_sectors; if (unlikely(bio->bi_rw & REQ_FLUSH)) { md_flush_request(mddev, bio); @@ -895,7 +897,6 @@ static int make_request(mddev_t *mddev, struct bio * bio) /* * read balancing logic: */ - int max_sectors; int disk; int slot; @@ -925,8 +926,6 @@ read_again: /* Could not read all from this device, so we will * need another r10_bio. */ - int sectors_handled; - sectors_handled = (r10_bio->sectors + max_sectors - bio->bi_sector); r10_bio->sectors = max_sectors; @@ -963,13 +962,22 @@ read_again: /* first select target devices under rcu_lock and * inc refcount on their rdev. Record them by setting * bios[x] to bio + * If there are known/acknowledged bad blocks on any device + * on which we have seen a write error, we want to avoid + * writing to those blocks. This potentially requires several + * writes to write around the bad blocks. Each set of writes + * gets its own r10_bio with a set of bios attached. The number + * of r10_bios is recored in bio->bi_phys_segments just as with + * the read case. */ plugged = mddev_check_plugged(mddev); raid10_find_phys(conf, r10_bio); - retry_write: +retry_write: blocked_rdev = NULL; rcu_read_lock(); + max_sectors = r10_bio->sectors; + for (i = 0; i < conf->copies; i++) { int d = r10_bio->devs[i].devnum; mdk_rdev_t *rdev = rcu_dereference(conf->mirrors[d].rdev); @@ -978,13 +986,55 @@ read_again: blocked_rdev = rdev; break; } - if (rdev && !test_bit(Faulty, &rdev->flags)) { - atomic_inc(&rdev->nr_pending); - r10_bio->devs[i].bio = bio; - } else { - r10_bio->devs[i].bio = NULL; + r10_bio->devs[i].bio = NULL; + if (!rdev || test_bit(Faulty, &rdev->flags)) { set_bit(R10BIO_Degraded, &r10_bio->state); + continue; + } + if (test_bit(WriteErrorSeen, &rdev->flags)) { + sector_t first_bad; + sector_t dev_sector = r10_bio->devs[i].addr; + int bad_sectors; + int is_bad; + + is_bad = is_badblock(rdev, dev_sector, + max_sectors, + &first_bad, &bad_sectors); + if (is_bad < 0) { + /* Mustn't write here until the bad block + * is acknowledged + */ + atomic_inc(&rdev->nr_pending); + set_bit(BlockedBadBlocks, &rdev->flags); + blocked_rdev = rdev; + break; + } + if (is_bad && first_bad <= dev_sector) { + /* Cannot write here at all */ + bad_sectors -= (dev_sector - first_bad); + if (bad_sectors < max_sectors) + /* Mustn't write more than bad_sectors + * to other devices yet + */ + max_sectors = bad_sectors; + /* We don't set R10BIO_Degraded as that + * only applies if the disk is missing, + * so it might be re-added, and we want to + * know to recover this chunk. + * In this case the device is here, and the + * fact that this chunk is not in-sync is + * recorded in the bad block log. + */ + continue; + } + if (is_bad) { + int good_sectors = first_bad - dev_sector; + if (good_sectors < max_sectors) + max_sectors = good_sectors; + } } + r10_bio->devs[i].bio = bio; + atomic_inc(&rdev->nr_pending); } rcu_read_unlock(); @@ -1004,8 +1054,22 @@ read_again: goto retry_write; } + if (max_sectors < r10_bio->sectors) { + /* We are splitting this into multiple parts, so + * we need to prepare for allocating another r10_bio. + */ + r10_bio->sectors = max_sectors; + spin_lock_irq(&conf->device_lock); + if (bio->bi_phys_segments == 0) + bio->bi_phys_segments = 2; + else + bio->bi_phys_segments++; + spin_unlock_irq(&conf->device_lock); + } + sectors_handled = r10_bio->sector + max_sectors - bio->bi_sector; + atomic_set(&r10_bio->remaining, 1); - bitmap_startwrite(mddev->bitmap, bio->bi_sector, r10_bio->sectors, 0); + bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0); for (i = 0; i < conf->copies; i++) { struct bio *mbio; @@ -1014,10 +1078,12 @@ read_again: continue; mbio = bio_clone_mddev(bio, GFP_NOIO, mddev); + md_trim_bio(mbio, r10_bio->sector - bio->bi_sector, + max_sectors); r10_bio->devs[i].bio = mbio; - mbio->bi_sector = r10_bio->devs[i].addr+ - conf->mirrors[d].rdev->data_offset; + mbio->bi_sector = (r10_bio->devs[i].addr+ + conf->mirrors[d].rdev->data_offset); mbio->bi_bdev = conf->mirrors[d].rdev->bdev; mbio->bi_end_io = raid10_end_write_request; mbio->bi_rw = WRITE | do_sync | do_fua; @@ -1042,6 +1108,21 @@ read_again: /* In case raid10d snuck in to freeze_array */ wake_up(&conf->wait_barrier); + if (sectors_handled < (bio->bi_size >> 9)) { + /* We need another r1_bio. It has already been counted + * in bio->bi_phys_segments. + */ + r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); + + r10_bio->master_bio = bio; + r10_bio->sectors = (bio->bi_size >> 9) - sectors_handled; + + r10_bio->mddev = mddev; + r10_bio->sector = bio->bi_sector + sectors_handled; + r10_bio->state = 0; + goto retry_write; + } + if (do_sync || !mddev->bitmap || !plugged) md_wakeup_thread(mddev->thread); return 0; |