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Commit 698b18c1 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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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: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6be9d494

drivers/md/raid1.c

+13 −2
Original line number Original line 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);

					rdev_dec_pending(conf->mirrors[i].rdev, mddev);

				} else {

				} else {

					/* fixup the bio for reuse */

					/* fixup the bio for reuse */

					int size;

					sbio->bi_vcnt = vcnt;

					sbio->bi_vcnt = vcnt;

					sbio->bi_size = r1_bio->sectors << 9;

					sbio->bi_size = r1_bio->sectors << 9;

					sbio->bi_idx = 0;

					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 +

					sbio->bi_sector = r1_bio->sector +

						conf->mirrors[i].rdev->data_offset;

						conf->mirrors[i].rdev->data_offset;

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

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

					for (j = 0; j < vcnt ; j++)

					size = sbio->bi_size;

						memcpy(page_address(sbio->bi_io_vec[j].bv_page),

					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_address(pbio->bi_io_vec[j].bv_page),

						       PAGE_SIZE);

						       PAGE_SIZE);

					}





				}

				}

			}

			}