block: fix wrong mode for blkdev_put() from disk_scan_partitions()

mainline inclusion
from mainline-v6.3-rc2
commit 428913bc
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6MQLP
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e5cfefa97bccf956ea0bb6464c1f6c84fd7a8d9f

--------------------------------

If disk_scan_partitions() is called with 'FMODE_EXCL',
blkdev_get_by_dev() will be called without 'FMODE_EXCL', however, follow
blkdev_put() is still called with 'FMODE_EXCL', which will cause
'bd_holders' counter to leak.

Fix the problem by using the right mode for blkdev_put().

Reported-by: syzbot+2bcc0d79e548c4f62a59@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/f9649d501bc8c3444769418f6c26263555d9d3be.camel@linux.ibm.com/T/Tested-by: NJulian Ruess <julianr@linux.ibm.com>
Fixes: e5cfefa9 ("block: fix scan partition for exclusively open device again")
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NHou Tao <houtao1@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>

block/genhd.c

@@ -768,7 +768,7 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 	if (IS_ERR(bdev))
 		ret = PTR_ERR(bdev);
 	else
-		blkdev_put(bdev, mode);
+		blkdev_put(bdev, mode & ~FMODE_EXCL);
 
 	if (!(mode & FMODE_EXCL)) {
 		bd_abort_claiming(claim, claim, disk_scan_partitions);