[PATCH v2 2/2] block: warn once for each partition in bio_check_ro()

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

Commit 1b0a151c10a6 ("blk-core: use pr_warn_ratelimited() in
bio_check_ro()") fix message storm by limit the rate, however, there
will still be lots of message in the long term. Fix it better by warn
once for each partition.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 block/blk-core.c          | 14 +++++++++++---
 include/linux/blk_types.h |  1 +
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index f9f8b12ba626..6575f684d41e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -502,9 +502,17 @@ static inline void bio_check_ro(struct bio *bio)
 	if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) {
 		if (op_is_flush(bio->bi_opf) && !bio_sectors(bio))
 			return;
-		pr_warn_ratelimited("Trying to write to read-only block-device %pg\n",
-				    bio->bi_bdev);
-		/* Older lvm-tools actually trigger this */
+
+		if (bdev_flagged(bio->bi_bdev, BD_FLAG_RO_WARNED))
+			return;
+
+		bdev_set_flag(bio->bi_bdev, BD_FLAG_RO_WARNED);
+		/*
+		 * Use ioctl to set underlying disk of raid/dm to read-only
+		 * will trigger this.
+		 */
+		pr_warn("Trying to write to read-only block-device %pg\n",
+			bio->bi_bdev);
 	}
 }
 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index f7a7965eeb25..07abd0165226 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -41,6 +41,7 @@ struct bio_crypt_ctx;
 #define BD_FLAG_WRITE_HOLDER	1
 #define BD_FLAG_HAS_SUBMIT_BIO	2
 #define BD_FLAG_MAKE_IT_FAIL	3
+#define BD_FLAG_RO_WARNED	4
 
 struct block_device {
 	sector_t		bd_start_sect;
-- 
2.39.2