From: Jens Axboe <axboe@kernel.dk>
Date: Tue, 14 Aug 2018 16:52:40 +0000 (-0600)
Subject: block: don't warn for flush on read-only device
X-Git-Tag: v4.18.8~116
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b02fd8a8dc25e237b2f8b78ff662c6b4d6995598;p=thirdparty%2Fkernel%2Fstable.git

block: don't warn for flush on read-only device

[ Upstream commit b089cfd95d32638335c551651a8e00fd2c4edb0b ]

Don't warn for a flush issued to a read-only device. It's not strictly
a writable command, as it doesn't change any on-media data by itself.

Reported-by: Stefan Agner <stefan@agner.ch>
Fixes: 721c7fc701c7 ("block: fail op_is_write() requests to read-only partitions")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/block/blk-core.c b/block/blk-core.c
index 1646ea85dadeb..746a5eac45410 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2159,7 +2159,9 @@ static inline bool should_fail_request(struct hd_struct *part,
 
 static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part)
 {
-	if (part->policy && op_is_write(bio_op(bio))) {
+	const int op = bio_op(bio);
+
+	if (part->policy && (op_is_write(op) && !op_is_flush(op))) {
 		char b[BDEVNAME_SIZE];
 
 		WARN_ONCE(1,