Commit e3b9703e authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] md: yet another attempt to get bitmap-based resync to do the right thing in all cases... 



Firstly, R1BIO_Degraded was being set in a number of places in the resync
code, but is never used there, so get rid of those settings.

Then: When doing a resync, we want to clear the bit in the bitmap iff the
array will be non-degraded when the sync has completed.  However the current
code would clear the bitmap if the array was non-degraded when the resync
*started*, which obviously isn't right (it is for 'resync' but not for
'recovery' - i.e.  rebuilding a failed drive).

This patch calculated 'still_degraded' and uses the to tell bitmap_start_sync
whether this sync should clear the corresponding bit.

Signed-off-by: default avatarNeil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 193f1c93

drivers/md/raid1.c

+15 −14
Original line number Diff line number Diff line
@@ -893,7 +893,6 @@ static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error) 
	if (!uptodate) {

		md_error(r1_bio->mddev,

			 conf->mirrors[r1_bio->read_disk].rdev);

		set_bit(R1BIO_Degraded, &r1_bio->state);

	} else

		set_bit(R1BIO_Uptodate, &r1_bio->state);

	rdev_dec_pending(conf->mirrors[r1_bio->read_disk].rdev, conf->mddev);
@@ -918,10 +917,9 @@ static int end_sync_write(struct bio *bio, unsigned int bytes_done, int error) 
			mirror = i;

			break;

		}

	if (!uptodate) {

	if (!uptodate)

		md_error(mddev, conf->mirrors[mirror].rdev);

		set_bit(R1BIO_Degraded, &r1_bio->state);

	}



	update_head_pos(mirror, r1_bio);



	if (atomic_dec_and_test(&r1_bio->remaining)) {
@@ -1109,6 +1107,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 
	int i;

	int write_targets = 0;

	int sync_blocks;

	int still_degraded = 0;



	if (!conf->r1buf_pool)

	{
@@ -1137,7 +1136,10 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 
		return 0;

	}



	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, mddev->degraded) &&

	/* before building a request, check if we can skip these blocks..

	 * This call the bitmap_start_sync doesn't actually record anything

	 */

	if (!bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&

	    !conf->fullsync) {

		/* We can skip this block, and probably several more */

		*skipped = 1;
@@ -1203,24 +1205,23 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 
		if (i == disk) {

			bio->bi_rw = READ;

			bio->bi_end_io = end_sync_read;

		} else if (conf->mirrors[i].rdev &&

			   !conf->mirrors[i].rdev->faulty &&

			   (!conf->mirrors[i].rdev->in_sync ||

			    sector_nr + RESYNC_SECTORS > mddev->recovery_cp)) {

		} else if (conf->mirrors[i].rdev == NULL ||

			   conf->mirrors[i].rdev->faulty) {

			still_degraded = 1;

			continue;

		} else if (!conf->mirrors[i].rdev->in_sync ||

			   sector_nr + RESYNC_SECTORS > mddev->recovery_cp) {

			bio->bi_rw = WRITE;

			bio->bi_end_io = end_sync_write;

			write_targets ++;

		} else

			/* no need to read or write here */

			continue;

		bio->bi_sector = sector_nr + conf->mirrors[i].rdev->data_offset;

		bio->bi_bdev = conf->mirrors[i].rdev->bdev;

		bio->bi_private = r1_bio;

	}



	if (write_targets + 1 < conf->raid_disks)

		/* array degraded, can't clear bitmap */

		set_bit(R1BIO_Degraded, &r1_bio->state);



	if (write_targets == 0) {

		/* There is nowhere to write, so all non-sync

		 * drives must be failed - so we are finished
@@ -1243,7 +1244,7 @@ static sector_t sync_request(mddev_t *mddev, sector_t sector_nr, int *skipped, i 
			break;

		if (sync_blocks == 0) {

			if (!bitmap_start_sync(mddev->bitmap, sector_nr,

					&sync_blocks, mddev->degraded) &&

					&sync_blocks, still_degraded) &&

					!conf->fullsync)

				break;

			if (sync_blocks < (PAGE_SIZE>>9))

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