[PATCH] md: fix possible problem in raid1/raid10 error overwriting
The code to overwrite/reread for addressing read errors in raid1/raid10
currently assumes that the read will not alter the buffer which could be used
to write to the next device. This is not a safe assumption to make.
So we split the loops into a overwrite loop and a separate re-read loop, so
that the writing is complete before reading is attempted.
Cc: Paul Clements <paul.clements@steeleye.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index f23d52c..9647ebb 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1421,6 +1421,7 @@
} while (!success && sl != r10_bio->read_slot);
if (success) {
+ int start = sl;
/* write it back and re-read */
while (sl != r10_bio->read_slot) {
int d;
@@ -1434,14 +1435,27 @@
if (sync_page_io(rdev->bdev,
r10_bio->devs[sl].addr +
sect + rdev->data_offset,
- s<<9, conf->tmppage, WRITE) == 0 ||
- sync_page_io(rdev->bdev,
- r10_bio->devs[sl].addr +
- sect + rdev->data_offset,
- s<<9, conf->tmppage, READ) == 0) {
+ s<<9, conf->tmppage, WRITE) == 0)
/* Well, this device is dead */
md_error(mddev, rdev);
- }
+ }
+ }
+ sl = start;
+ while (sl != r10_bio->read_slot) {
+ int d;
+ if (sl==0)
+ sl = conf->copies;
+ sl--;
+ d = r10_bio->devs[sl].devnum;
+ rdev = conf->mirrors[d].rdev;
+ if (rdev &&
+ test_bit(In_sync, &rdev->flags)) {
+ if (sync_page_io(rdev->bdev,
+ r10_bio->devs[sl].addr +
+ sect + rdev->data_offset,
+ s<<9, conf->tmppage, READ) == 0)
+ /* Well, this device is dead */
+ md_error(mddev, rdev);
}
}
} else {