linux-kernel - [PATCH AUTOSEL 5.5 75/75] block: fix busy device checking in blk_drop

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Date:   Sat, 18 Apr 2020 10:09:10 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Christoph Hellwig <hch@....de>, Qian Cai <cai@....pw>,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>,
        linux-block@...r.kernel.org
Subject: [PATCH AUTOSEL 5.5 75/75] block: fix busy device checking in blk_drop_partitions again

From: Christoph Hellwig <hch@....de>

[ Upstream commit cb6b771b05c3026a85ed4817c1b87c5e6f41d136 ]

The previous fix had an off by one in the bd_openers checking, counting
the callers blkdev_get.

Fixes: d3ef5536274f ("block: fix busy device checking in blk_drop_partitions")
Reported-by: Qian Cai <cai@....pw>
Signed-off-by: Christoph Hellwig <hch@....de>
Tested-by: Qian Cai <cai@....pw>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 block/partition-generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/partition-generic.c b/block/partition-generic.c
index 5f3b2a959aa51..ebe4c2e9834bd 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -468,7 +468,7 @@ int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev)
 
 	if (!disk_part_scan_enabled(disk))
 		return 0;
-	if (bdev->bd_part_count || bdev->bd_openers)
+	if (bdev->bd_part_count || bdev->bd_openers > 1)
 		return -EBUSY;
 	res = invalidate_partition(disk, 0);
 	if (res)
-- 
2.20.1