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>
This commit is contained in:
NeilBrown 2011-07-28 11:39:24 +10:00
parent e875ecea26
commit d4432c23be

View File

@ -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;