[PATCH] md: raid10 read-error handling - resync and read-only
Add in correct read-error handling for resync and read-only situations.
When read-only, we don't over-write, so we need to mark the failed drive in
the r10_bio so we don't re-try it. During resync, we always read all blocks,
so if there is a read error, we simply over-write it with the good block that
we found (assuming we found one).
Note that the recovery case still isn't handled in an interesting way. There
is nothing useful to do for the 2-copies case. If there are 3 or more copies,
then we could try reading from one of the non-missing copies, but this is a
bit complicated and very rarely would be used, so I'm leaving it for now.
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 64bb4dd..3f8df2e 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -172,7 +172,7 @@
for (i = 0; i < conf->copies; i++) {
struct bio **bio = & r10_bio->devs[i].bio;
- if (*bio)
+ if (*bio && *bio != IO_BLOCKED)
bio_put(*bio);
*bio = NULL;
}
@@ -500,6 +500,7 @@
disk = r10_bio->devs[slot].devnum;
while ((rdev = rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
+ r10_bio->devs[slot].bio == IO_BLOCKED ||
!test_bit(In_sync, &rdev->flags)) {
slot++;
if (slot == conf->copies) {
@@ -517,6 +518,7 @@
slot = 0;
disk = r10_bio->devs[slot].devnum;
while ((rdev=rcu_dereference(conf->mirrors[disk].rdev)) == NULL ||
+ r10_bio->devs[slot].bio == IO_BLOCKED ||
!test_bit(In_sync, &rdev->flags)) {
slot ++;
if (slot == conf->copies) {
@@ -537,6 +539,7 @@
if ((rdev=rcu_dereference(conf->mirrors[ndisk].rdev)) == NULL ||
+ r10_bio->devs[nslot].bio == IO_BLOCKED ||
!test_bit(In_sync, &rdev->flags))
continue;
@@ -1104,7 +1107,6 @@
static int end_sync_read(struct bio *bio, unsigned int bytes_done, int error)
{
- int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
r10bio_t * r10_bio = (r10bio_t *)(bio->bi_private);
conf_t *conf = mddev_to_conf(r10_bio->mddev);
int i,d;
@@ -1119,7 +1121,10 @@
BUG();
update_head_pos(i, r10_bio);
d = r10_bio->devs[i].devnum;
- if (!uptodate)
+
+ if (test_bit(BIO_UPTODATE, &bio->bi_flags))
+ set_bit(R10BIO_Uptodate, &r10_bio->state);
+ else if (!test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery))
md_error(r10_bio->mddev,
conf->mirrors[d].rdev);
@@ -1209,25 +1214,30 @@
fbio = r10_bio->devs[i].bio;
/* now find blocks with errors */
- for (i=first+1 ; i < conf->copies ; i++) {
- int vcnt, j, d;
+ for (i=0 ; i < conf->copies ; i++) {
+ int j, d;
+ int vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
- if (!test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags))
- continue;
- /* We know that the bi_io_vec layout is the same for
- * both 'first' and 'i', so we just compare them.
- * All vec entries are PAGE_SIZE;
- */
tbio = r10_bio->devs[i].bio;
- vcnt = r10_bio->sectors >> (PAGE_SHIFT-9);
- for (j = 0; j < vcnt; j++)
- if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
- page_address(tbio->bi_io_vec[j].bv_page),
- PAGE_SIZE))
- break;
- if (j == vcnt)
+
+ if (tbio->bi_end_io != end_sync_read)
continue;
- mddev->resync_mismatches += r10_bio->sectors;
+ if (i == first)
+ continue;
+ if (test_bit(BIO_UPTODATE, &r10_bio->devs[i].bio->bi_flags)) {
+ /* We know that the bi_io_vec layout is the same for
+ * both 'first' and 'i', so we just compare them.
+ * All vec entries are PAGE_SIZE;
+ */
+ for (j = 0; j < vcnt; j++)
+ if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
+ page_address(tbio->bi_io_vec[j].bv_page),
+ PAGE_SIZE))
+ break;
+ if (j == vcnt)
+ continue;
+ mddev->resync_mismatches += r10_bio->sectors;
+ }
if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
/* Don't fix anything. */
continue;
@@ -1308,7 +1318,10 @@
atomic_inc(&conf->mirrors[d].rdev->nr_pending);
md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
- generic_make_request(wbio);
+ if (test_bit(R10BIO_Uptodate, &r10_bio->state))
+ generic_make_request(wbio);
+ else
+ bio_endio(wbio, wbio->bi_size, -EIO);
}
@@ -1445,7 +1458,8 @@
unfreeze_array(conf);
bio = r10_bio->devs[r10_bio->read_slot].bio;
- r10_bio->devs[r10_bio->read_slot].bio = NULL;
+ r10_bio->devs[r10_bio->read_slot].bio =
+ mddev->ro ? IO_BLOCKED : NULL;
bio_put(bio);
mirror = read_balance(conf, r10_bio);
if (mirror == -1) {