Patch "RAID1: ignore discard error" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

RAID1: ignore discard error

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
raid1-ignore-discard-error.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Shaohua Li <[email protected]>
Date: Thu, 6 Oct 2016 14:09:16 -0700
Subject: RAID1: ignore discard error

From: Shaohua Li <[email protected]>

commit e3f948cd3283e4fbe5907f1f3967c839912f480e upstream.

If a write error occurs, raid1 will try to rewrite the bio in small chunk size. If the rewrite fails, raid1 will record the error in bad block. narrow_write_error will always use WRITE for the bio, but actually it could be a discard. Since discard bio hasn't payload, write the bio will cause different issues. But discard error isn't fatal, we can safely ignore it. This is what this patch does.

This issue should exist since discard is added, but only exposed with recent arbitrary bio size feature.

---
 drivers/md/raid1.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

@@ -407,11 +407,14 @@ static void raid1_end_write_request(stru
 	struct bio *to_put = NULL;
 	int mirror = find_bio_disk(r1_bio, bio);
 	struct md_rdev *rdev = conf->mirrors[mirror].rdev;
+	bool discard_error;
+
+	discard_error = bio->bi_error && bio_op(bio) == REQ_OP_DISCARD;
 
 	/*
 	 * 'one mirror IO has finished' event handler:
 	 */
-	if (bio->bi_error) {
+	if (bio->bi_error && !discard_error) {
 		set_bit(WriteErrorSeen,	&rdev->flags);
 		if (!test_and_set_bit(WantReplacement, &rdev->flags))
 			set_bit(MD_RECOVERY_NEEDED, &

@@ -448,7 +451,7 @@ static void raid1_end_write_request(stru
 
 		/* Maybe we can clear some bad blocks. */
 		if (is_badblock(rdev, r1_bio->sector, r1_bio->sectors,
-				&first_bad, &bad_sectors)) {
+				&first_bad, &bad_sectors) && !discard_error) {
 			r1_bio->bios[mirror] = IO_MADE_GOOD;
 			set_bit(R1BIO_MadeGood, &r1_bio->state);
 		}

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/raid1-ignore-discard-error.patch queue-4.8/raid10-ignore-discard-error.patch queue-4.8/md-be-careful-not-lot-leak-internal-curr_resync-value-into-metadata.-all.patch