Commit 698b18c1 authored May 23, 2008 by NeilBrown Committed by Linus Torvalds May 24, 2008

md: raid1: Fix restoration of bio between failed read and write.



When performing a "recovery" or "check" pass on a RAID1 array, we read
from each device and possible, if there is a difference or a read error,
write back to some devices.

We use the same 'bio' for both read and write, resetting various fields
between the two operations.

We forgot to reset bv_offset and bv_len however.  These are often left
unchanged, but in the case where there is an IO error one or two sectors
into a page, they are changed.

This results in correctable errors not being corrected properly.  It does
not result in any data corruption.

Cc: "Fairbanks, David" <David.Fairbanks@stratus.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6be9d494

drivers/md/raid1.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -1284,6 +1284,7 @@ static void sync_request_write(mddev_t mddev, r1bio_t r1_bio)
		rdev_dec_pending(conf->mirrors[i].rdev, mddev);
		} else {
		/* fixup the bio for reuse */
		int size;
		sbio->bi_vcnt = vcnt;
		sbio->bi_size = r1_bio->sectors << 9;
		sbio->bi_idx = 0;
		@@ -1297,10 +1298,20 @@ static void sync_request_write(mddev_t mddev, r1bio_t r1_bio)
		sbio->bi_sector = r1_bio->sector +
		conf->mirrors[i].rdev->data_offset;
		sbio->bi_bdev = conf->mirrors[i].rdev->bdev;
		for (j = 0; j < vcnt ; j++)
		memcpy(page_address(sbio->bi_io_vec[j].bv_page),
		size = sbio->bi_size;
		for (j = 0; j < vcnt ; j++) {
		struct bio_vec *bi;
		bi = &sbio->bi_io_vec[j];
		bi->bv_offset = 0;
		if (size > PAGE_SIZE)
		bi->bv_len = PAGE_SIZE;
		else
		bi->bv_len = size;
		size -= PAGE_SIZE;
		memcpy(page_address(bi->bv_page),
		page_address(pbio->bi_io_vec[j].bv_page),
		PAGE_SIZE);
		}

		}
		}

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