From nobody Sun Nov 24 05:42:00 2024 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 A773E1D63FD; Thu, 21 Nov 2024 14:17:29 +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=1732198649; cv=none; b=XZ0zUF08onWRZXrzpScA1pl7w4Qit2gc/jlCSTYyEtQsYnrAAw9A8cezNq8OVe4ntQI0vBla+h2TGdD/cViAshDhlgxyykO8cLGkIM6ati0hAIk/EpePPQyYD2heSli+F2DY1lCghxRHuC3+1Di4/Y+bGBJnwHI9jJosJApaxaI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732198649; c=relaxed/simple; bh=Nwing6hxd7cbL8mrx1UFhwO+4wTLgqqgFjW37N/tBsY=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=GgDlLtbMg9vTh7d0yOMIJrPwdhg9jC0f1vHUM96311FSTFVJD/v+2Qb89vIRstjpZBbmWgcnBq6sfFZKUt1Jhn5rUI1Ro8GZFfi2gstkklLGIWCYXf4dA5W13D56r1eA0Kvjc+Mwa1sav1JCwmS4VlFIMPscOvvrs6CjMHj7+KI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WFBO2pNb; 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="WFBO2pNb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2882C4CECC; Thu, 21 Nov 2024 14:17:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1732198649; bh=Nwing6hxd7cbL8mrx1UFhwO+4wTLgqqgFjW37N/tBsY=; h=From:To:Cc:Subject:Date:From; b=WFBO2pNbkJJdN3p7N5UR1GeTs2j6WYsbgzGfuu+5SGkRUCMTRmfBooHBQHQM/Fsg2 k9Zr14TBDhpekulan4sDjdyDiGe054/+vJ9NYTAP77515vh6ZgBuesca6wwOesiboQ aCrH2TzvD44QIcYNG59RfppvjzC/dgUc5oy80PlHtUiqdXk2J+MIX76aJzpYZSHyaj z5tHo5O2mUbCN25lZL+wiXfHhnWzuZ7Ed1CXzMLME7qT81YdoPwMEkLEmAIFubXkbK doltu3cGGVfqHr01kx4nvU6VFrC8b1a2UhsQv35/4W5nEZvBtHoSpYHB/dYH+Q+Ts6 qZvui8KMW5T6g== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu , stable@vger.kernel.org, Piergiorgio Sartor Subject: [PATCH] f2fs: fix to drop all discards after creating snapshot on lvm device Date: Thu, 21 Nov 2024 22:17:16 +0800 Message-Id: <20241121141716.3018855-1-chao@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Piergiorgio reported a bug in bugzilla as below: Reported-by: Piergiorgio Sartor ------------[ cut here ]------------ WARNING: CPU: 2 PID: 969 at fs/f2fs/segment.c:1330 RIP: 0010:__submit_discard_cmd+0x27d/0x400 [f2fs] Call Trace: __issue_discard_cmd+0x1ca/0x350 [f2fs] issue_discard_thread+0x191/0x480 [f2fs] kthread+0xcf/0x100 ret_from_fork+0x31/0x50 ret_from_fork_asm+0x1a/0x30 w/ below testcase, it can reproduce this bug quickly: - pvcreate /dev/vdb - vgcreate myvg1 /dev/vdb - lvcreate -L 1024m -n mylv1 myvg1 - mount /dev/myvg1/mylv1 /mnt/f2fs - dd if=3D/dev/zero of=3D/mnt/f2fs/file bs=3D1M count=3D20 - sync - rm /mnt/f2fs/file - sync - lvcreate -L 1024m -s -n mylv1-snapshot /dev/myvg1/mylv1 - umount /mnt/f2fs The root cause is: it will update discard_max_bytes of mounted lvm device to zero after creating snapshot on this lvm device, then, __submit_discard_cmd() will pass parameter @nr_sects w/ zero value to __blkdev_issue_discard(), it returns a NULL bio pointer, result in panic. This patch changes as below for fixing: 1. Let's drop all remained discards in f2fs_unfreeze() if snapshot of lvm device is created. 2. Checking discard_max_bytes before submitting discard during __submit_discard_cmd(). Cc: stable@vger.kernel.org Fixes: 35ec7d574884 ("f2fs: split discard command in prior to block layer") Reported-by: Piergiorgio Sartor Closes: https://bugzilla.kernel.org/show_bug.cgi?id=3D219484 Signed-off-by: Chao Yu --- fs/f2fs/segment.c | 16 +++++++++------- fs/f2fs/super.c | 12 ++++++++++++ 2 files changed, 21 insertions(+), 7 deletions(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 7bdfe08ce9ea..af3fb3f6d9b5 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1290,16 +1290,18 @@ static int __submit_discard_cmd(struct f2fs_sb_info= *sbi, wait_list, issued); return 0; } - - /* - * Issue discard for conventional zones only if the device - * supports discard. - */ - if (!bdev_max_discard_sectors(bdev)) - return -EOPNOTSUPP; } #endif =20 + /* + * stop issuing discard for any of below cases: + * 1. device is conventional zone, but it doesn't support discard. + * 2. device is regulare device, after snapshot it doesn't support + * discard. + */ + if (!bdev_max_discard_sectors(bdev)) + return -EOPNOTSUPP; + trace_f2fs_issue_discard(bdev, dc->di.start, dc->di.len); =20 lstart =3D dc->di.lstart; diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index c0670cd61956..fc7d463dee15 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1760,6 +1760,18 @@ static int f2fs_freeze(struct super_block *sb) =20 static int f2fs_unfreeze(struct super_block *sb) { + struct f2fs_sb_info *sbi =3D F2FS_SB(sb); + + /* + * It will update discard_max_bytes of mounted lvm device to zero + * after creating snapshot on this lvm device, let's drop all + * remained discards. + * We don't need to disable real-time discard because discard_max_bytes + * will recover after removal of snapshot. + */ + if (test_opt(sbi, DISCARD) && !f2fs_hw_support_discard(sbi)) + f2fs_issue_discard_timeout(sbi); + clear_sbi_flag(F2FS_SB(sb), SBI_IS_FREEZING); return 0; } --=20 2.40.1