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Commit d4432c23 authored by NeilBrown's avatar NeilBrown
Browse files

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: default avatarNeilBrown <neilb@suse.de>
parent e875ecea

drivers/md/raid10.c

+93 −12
Original line number Diff line number Diff line
@@ -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 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
			/* 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;
@@ -963,6 +962,13 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
	/* 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);
@@ -970,6 +976,8 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
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 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
			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;

		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 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
		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 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
			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 @@ static int make_request(mddev_t *mddev, struct bio * bio) 
	/* 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;