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

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

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From e3f948cd3283e4fbe5907f1f3967c839912f480e Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@fb.com>
Date: Thu, 6 Oct 2016 14:09:16 -0700
Subject: RAID1: ignore discard error

From: Shaohua Li <shli@fb.com>

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.

Reported-and-tested-by: Sitsofe Wheeler <sitsofe@gmail.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -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 shli@fb.com 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