From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 22A453233E8; Mon, 24 Aug 2026 13:32:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787578376; cv=none; b=EhFqKK/Pw+/FGoPBB9RkenjuX3ZakO+GAi8r/8dYu2NE/sbuiksGqKXeWf/H1vPbDYto1GmFDhDoWcTBGfGAHoSQE5M3V6x80VTdZXQviAxxAMCS0sEjyv1Shb02dnGLs24C1Se7/Ic3rT7Fe3N6dE/aYIRsdZ9CmIp20r5TEs8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787578376; c=relaxed/simple; bh=bqxr7tJMlMv9QBqyGWY6/PLr9AYldw0DmoB+D9A7GFc=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=ZFj6nsQdYgX86BBFMLhLO60oIauvyFh6LaCzeeEsttca+LZZsDBx1sC9PBDLazr0fjPksVmVk6SLV+r+yC2/knvzb3EihNW8a1gMj2kVfaknFn6Enpth3KNKL2EJm00NhIsvTeYITojN1R3r6aYMSAC+Ggn3VS7jgbQ76psEl9c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G8kAsPfC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="G8kAsPfC" Received: by smtp.kernel.org (Postfix) with ESMTPS id A9339C2BCFB; Mon, 24 Aug 2026 13:32:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1787578375; bh=bqxr7tJMlMv9QBqyGWY6/PLr9AYldw0DmoB+D9A7GFc=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=G8kAsPfCd3v0QZK65ZQP4KbhzUnGfCQ/YNdkoQ3WwCT14wzGj9hReIH273n2r91cC hf9cQNH9FaJ/SegJFP5aGHT+oSKJgm80aw235CTOzila7GC58WdE3xJQgbnh3pLrQ4 WM+MOFoLPeHYdlmGlNN7hiznkG/ykacFsN7uBre0tLzM2dmmPP4vFHSrKCsef9+AAu oITHQNzQTS01lFe580bdiAAWEN0TmE/7m+Sn/alE9JlaAHLvUaDxgpysh07csx+4Gw 0hxsbC4hK2ZL98jZpXhYDhFXcqtp0LsIjBdPRveODY9Bxf5txAk1Zdg9c8XbhyJlqe ic6rZ/mqXn1rA== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 887D9C5DF94; Mon, 24 Aug 2026 13:32:55 +0000 (UTC) From: Daan De Meyer via B4 Relay Date: Mon, 24 Aug 2026 15:32:48 +0200 Subject: [PATCH v2 2/2] nbd: drop stale partitions on NBD_CLEAR_SOCK Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260824-b4-loop-nbd-stale-partitions-v2-2-9815a577cebd@amutable.com> References: <20260824-b4-loop-nbd-stale-partitions-v2-0-9815a577cebd@amutable.com> In-Reply-To: <20260824-b4-loop-nbd-stale-partitions-v2-0-9815a577cebd@amutable.com> To: Jens Axboe , Christian Brauner , Josef Bacik Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, nbd@other.debian.org, Christoph Hellwig , Bart Van Assche , Shin'ichiro Kawasaki , Daan De Meyer , stable@vger.kernel.org X-Mailer: b4 0.15.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1787578374; l=2227; i=daan@amutable.com; s=20260712; h=from:subject:message-id; bh=IJsYukTCp+gKDcCUl73TRLZtzYPIPmGwnx1/NOZHD4E=; b=+3LKI5LgUmNDygotKLNLsRXKAEF5uxws+wjt9ChSEsGXFVqJWzbH+YSsSCGOVnRyU54fmfXoR ve0kGD09ernCUHrWvT8l+uWR/XeooSDOTbqrxfcNt+Ur0EoXvdUX9wz X-Developer-Key: i=daan@amutable.com; a=ed25519; pk=I1l+WwrtmzRgofA5SQ1wTuJi18fjh91w+f5uRkFeZEA= X-Endpoint-Received: by B4 Relay for daan@amutable.com/20260712 with auth_id=868 X-Original-From: Daan De Meyer Reply-To: daan@amutable.com From: Daan De Meyer Commit 267ec4d7223a ("loop: fix partition scan race between udev and loop_reread_partitions()") stopped disk_force_media_change() from setting GD_NEED_PART_SCAN. Besides requesting a rescan, that bit was what removed stale partitions on the next open, as bdev_disk_changed() drops all partitions before it consults disk_has_partscan(). nbd_clear_sock_ioctl() relied on that. It zeroes the capacity through nbd_bdev_reset(), but nothing removes the partitions of the disconnected device anymore. With the default max_part=16 they linger until the next connect sets GD_NEED_PART_SCAN again. With max_part=0 nothing ever sets it, so they are never removed at all, even though nbd does not set GENHD_FL_NO_PART and partitions can therefore still be added with BLKPG. Set GD_NEED_PART_SCAN in nbd_clear_sock_ioctl() so the partitions are dropped on the next open. Calling bdev_disk_changed() directly is not an option as it needs open_mutex, which nbd_open() acquires under config_lock. Fixes: 267ec4d7223a ("loop: fix partition scan race between udev and loop_reread_partitions()") Cc: stable@vger.kernel.org Reviewed-by: Christian Brauner (Amutable) Reviewed-by: Bart Van Assche Tested-by: Shin'ichiro Kawasaki Signed-off-by: Daan De Meyer --- drivers/block/nbd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index ffce519bf008..09b4ad70a5d7 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1616,6 +1616,13 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd) nbd_clear_sock(nbd); disk_force_media_change(nbd->disk); nbd_bdev_reset(nbd); + /* + * Drop the partitions of the disconnected device on the next open. + * They can exist even with max_part zero as they may have been added + * manually with BLKPG. Dropping them here is not possible as that + * needs open_mutex, which nbd_open() acquires under config_lock. + */ + set_bit(GD_NEED_PART_SCAN, &nbd->disk->state); if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, &nbd->config->runtime_flags)) nbd_config_put(nbd); -- 2.54.0