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Date:   Mon, 10 Aug 2020 19:16:32 +0200
From:   Lennart Poettering <mzxreary@0pointer.de>
To:     linux-block <linux-block@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
        Yang Xu <xuyang2018.jy@cn.fujitsu.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH v2] loop: unset GENHD_FL_NO_PART_SCAN on LOOP_CONFIGURE
Message-ID: <20200810171632.GA226564@gardel-login>
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Sender: linux-kernel-owner@vger.kernel.org
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When LOOP_CONFIGURE is used with LO_FLAGS_PARTSCAN we need to propagate
this into the GENHD_FL_NO_PART_SCAN. LOOP_SETSTATUS does this,
LOOP_CONFIGURE doesn't so far. Effect is that setting up a loopback
device with partition scanning doesn't actually work when LOOP_CONFIGURE
is issued, though it works fine with LOOP_SETSTATUS.

Let's correct that and propagate the flag in LOOP_CONFIGURE too.

Fixes: 3448914e8cc5("loop: Add LOOP_CONFIGURE ioctl")

Signed-off-by: Lennart Poettering <lennart@poettering.net>
Acked-by: Martijn Coenen <maco@android.com>
---
 drivers/block/loop.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d18160146226..2f137d6ce169 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1171,6 +1171,8 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
 	if (part_shift)
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
 	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
+	if (partscan)
+		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;

 	/* Grab the block_device to prevent its destruction after we
 	 * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev).
--
2.26.2