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[3.11.y.z,extended,stable] Patch "md/raid1: restore ability for check and repair to fix read errors." has been added to staging queue

Message ID 1392985464-4964-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques Feb. 21, 2014, 12:24 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    md/raid1: restore ability for check and repair to fix read errors.

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From bde030df7870deda5bbd1f0c9b218ffe95eacc57 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Wed, 5 Feb 2014 12:17:01 +1100
Subject: md/raid1: restore ability for check and repair to fix read errors.

commit 1877db75589a895bbdc4c4c3f23558e57b521141 upstream.

commit 30bc9b53878a9921b02e3b5bc4283ac1c6de102a
    md/raid1: fix bio handling problems in process_checks()

Move the bio_reset() to a point before where BIO_UPTODATE is checked,
so that check now always report that the bio is uptodate, even if it is not.

This causes process_check() to sometimes treat read-errors as
successful matches so the good data isn't written out.

This patch preserves the flag until it is needed.

Bug was introduced in 3.11, but backported to 3.10-stable (as it fixed
an even worse bug).  So suitable for any -stable since 3.10.

Reported-and-tested-by: Michael Tokarev <mjt@tls.msk.ru>
Fixed: 30bc9b53878a9921b02e3b5bc4283ac1c6de102a
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 drivers/md/raid1.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

--
1.9.0
diff mbox

Patch

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index aacf6bf..6edc2db 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1855,11 +1855,15 @@  static int process_checks(struct r1bio *r1_bio)
 	for (i = 0; i < conf->raid_disks * 2; i++) {
 		int j;
 		int size;
+		int uptodate;
 		struct bio *b = r1_bio->bios[i];
 		if (b->bi_end_io != end_sync_read)
 			continue;
-		/* fixup the bio for reuse */
+		/* fixup the bio for reuse, but preserve BIO_UPTODATE */
+		uptodate = test_bit(BIO_UPTODATE, &b->bi_flags);
 		bio_reset(b);
+		if (!uptodate)
+			clear_bit(BIO_UPTODATE, &b->bi_flags);
 		b->bi_vcnt = vcnt;
 		b->bi_size = r1_bio->sectors << 9;
 		b->bi_sector = r1_bio->sector +
@@ -1892,11 +1896,14 @@  static int process_checks(struct r1bio *r1_bio)
 		int j;
 		struct bio *pbio = r1_bio->bios[primary];
 		struct bio *sbio = r1_bio->bios[i];
+		int uptodate = test_bit(BIO_UPTODATE, &sbio->bi_flags);

 		if (sbio->bi_end_io != end_sync_read)
 			continue;
+		/* Now we can 'fixup' the BIO_UPTODATE flag */
+		set_bit(BIO_UPTODATE, &sbio->bi_flags);

-		if (test_bit(BIO_UPTODATE, &sbio->bi_flags)) {
+		if (uptodate) {
 			for (j = vcnt; j-- ; ) {
 				struct page *p, *s;
 				p = pbio->bi_io_vec[j].bv_page;
@@ -1911,7 +1918,7 @@  static int process_checks(struct r1bio *r1_bio)
 		if (j >= 0)
 			atomic64_add(r1_bio->sectors, &mddev->resync_mismatches);
 		if (j < 0 || (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)
-			      && test_bit(BIO_UPTODATE, &sbio->bi_flags))) {
+			      && uptodate)) {
 			/* No need to write to this device. */
 			sbio->bi_end_io = NULL;
 			rdev_dec_pending(conf->mirrors[i].rdev, mddev);