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authorNeilBrown <neilb@suse.de>2013-07-16 16:50:47 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-25 14:07:28 -0700
commit2dc04d3333049098691eb652e06d52fbd80771d2 (patch)
tree368daf6f090dbbb6402bcbcc5c287c8254617cbf /drivers/md
parent4b5c14511c401edf5ea78e2592c7043456deb595 (diff)
md/raid10: fix two problems with RAID10 resync.
commit 7bb23c4934059c64cbee2e41d5d24ce122285176 upstream. 1/ When an different between blocks is found, data is copied from one bio to the other. However bv_len is used as the length to copy and this could be zero. So use r10_bio->sectors to calculate length instead. Using bv_len was probably always a bit dubious, but the introduction of bio_advance made it much more likely to be a problem. 2/ When preparing some blocks for sync, we don't set BIO_UPTODATE except on bios that we schedule for a read. This ensures that missing/failed devices don't confuse the loop at the top of sync_request write. Commit 8be185f2c9d54d6 "raid10: Use bio_reset()" removed a loop which set BIO_UPTDATE on all appropriate bios. So we need to re-add that flag. These bugs were introduced in 3.10, so this patch is suitable for 3.10-stable, and can remove a potential for data corruption. Reported-by: Brassow Jonathan <jbrassow@redhat.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/raid10.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index d7bad6bc46d8..d61eb7ea0d81 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2075,11 +2075,17 @@ static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
* both 'first' and 'i', so we just compare them.
* All vec entries are PAGE_SIZE;
*/
- for (j = 0; j < vcnt; j++)
+ int sectors = r10_bio->sectors;
+ for (j = 0; j < vcnt; j++) {
+ int len = PAGE_SIZE;
+ if (sectors < (len / 512))
+ len = sectors * 512;
if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
page_address(tbio->bi_io_vec[j].bv_page),
- fbio->bi_io_vec[j].bv_len))
+ len))
break;
+ sectors -= len/512;
+ }
if (j == vcnt)
continue;
atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
@@ -3385,6 +3391,7 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
if (bio->bi_end_io == end_sync_read) {
md_sync_acct(bio->bi_bdev, nr_sectors);
+ set_bit(BIO_UPTODATE, &bio->bi_flags);
generic_make_request(bio);
}
}