[PATCH 4.19 053/101] nbd: fix a block_device refcount leak in nbd_release

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit 2bd645b2d3f0bacadaa6037f067538e1cd4e42ef ]

bdget_disk needs to be paired with bdput to not leak a reference
on the block device inode.

Fixes: 08ba91ee6e2c ("nbd: Add the nbd NBD_DISCONNECT_ON_CLOSE config flag.")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/block/nbd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 706115ecd9bee..517318bb350cf 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1448,6 +1448,7 @@ static void nbd_release(struct gendisk *disk, fmode_t mode)
 	if (test_bit(NBD_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
 			bdev->bd_openers == 0)
 		nbd_disconnect_and_put(nbd);
+	bdput(bdev);
 
 	nbd_config_put(nbd);
 	nbd_put(nbd);
-- 
2.27.0