Patch "RAID10: ignore discard error" has been added to the 4.8-stable tree

[<gregkh@linuxfoundation.org>]

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

    RAID10: 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:
     raid10-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 579ed34f7b751b8add233cba4cf755258dbdd60a Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@fb.com>
Date: Thu, 6 Oct 2016 14:13:52 -0700
Subject: RAID10: ignore discard error

From: Shaohua Li <shli@fb.com>

commit 579ed34f7b751b8add233cba4cf755258dbdd60a upstream.

This is the counterpart of raid10 fix. If a write error occurs, raid10
will try to rewrite the bio in small chunk size. If the rewrite fails,
raid10 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.

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

---
 drivers/md/raid10.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -447,6 +447,9 @@ static void raid10_end_write_request(str
 	struct r10conf *conf = r10_bio->mddev->private;
 	int slot, repl;
 	struct md_rdev *rdev = NULL;
+	bool discard_error;
+
+	discard_error = bio->bi_error && bio_op(bio) == REQ_OP_DISCARD;
 
 	dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
 
@@ -460,7 +463,7 @@ static void raid10_end_write_request(str
 	/*
 	 * this branch is our 'one mirror IO has finished' event handler:
 	 */
-	if (bio->bi_error) {
+	if (bio->bi_error && !discard_error) {
 		if (repl)
 			/* Never record new bad blocks to replacement,
 			 * just fail it.
@@ -503,7 +506,7 @@ static void raid10_end_write_request(str
 		if (is_badblock(rdev,
 				r10_bio->devs[slot].addr,
 				r10_bio->sectors,
-				&first_bad, &bad_sectors)) {
+				&first_bad, &bad_sectors) && !discard_error) {
 			bio_put(bio);
 			if (repl)
 				r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;


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