From patchwork Fri Nov 10 20:44:57 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 13452794 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 DBEC33B780 for ; Fri, 10 Nov 2023 20:45:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="T7yezgZ3" Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C8445279 for ; Fri, 10 Nov 2023 12:45:17 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 100191F8BD; Fri, 10 Nov 2023 20:45:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1699649116; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=xoT4pUKg1s0hiaFkzWUp1fPgYX4s4zFhfKWt4WpSplk=; b=T7yezgZ3KIukHWRz7PFt+c4bBFVXgkpsZsXEkPNOAZ2up31ipOEn/65JW1uSWXN5hVZKK1 vgeDO687SVvqXaMIv3GgJsGH8T6NbxJg6dje1JthKhE9BRa04QHreuQfQRaEF6w1oTuA2G Mfl1Ip+XZtd6dx9NGY+48XI6J4QUmaA= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id F3D4E13398; Fri, 10 Nov 2023 20:45:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id mWvkK1qWTmVKeQAAMHmgww (envelope-from ); Fri, 10 Nov 2023 20:45:14 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: syzbot+4d81015bc10889fd12ea@syzkaller.appspotmail.com Subject: [PATCH] btrfs: do not abort transaction if there is already an existing qgroup Date: Sat, 11 Nov 2023 07:14:57 +1030 Message-ID: X-Mailer: git-send-email 2.42.1 Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 [BUG] Syzbot reported a regression that after commit 6ed05643ddb1 ("btrfs: create qgroup earlier in snapshot creation") we can trigger transaction abort during subvolume creation: ------------[ cut here ]------------ BTRFS: Transaction aborted (error -17) WARNING: CPU: 0 PID: 5057 at fs/btrfs/transaction.c:1778 create_pending_snapshot+0x25f4/0x2b70 fs/btrfs/transaction.c:1778 Modules linked in: CPU: 0 PID: 5057 Comm: syz-executor225 Not tainted 6.6.0-syzkaller-15365-g305230142ae0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023 RIP: 0010:create_pending_snapshot+0x25f4/0x2b70 fs/btrfs/transaction.c:1778 Call Trace: create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1967 btrfs_commit_transaction+0xf1c/0x3730 fs/btrfs/transaction.c:2440 create_snapshot+0x4a5/0x7e0 fs/btrfs/ioctl.c:845 btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:995 btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1041 __btrfs_ioctl_snap_create+0x344/0x460 fs/btrfs/ioctl.c:1294 btrfs_ioctl_snap_create+0x13c/0x190 fs/btrfs/ioctl.c:1321 btrfs_ioctl+0xbbf/0xd40 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f2f791127b9 [CAUSE] The error number is -EEXIST, which can happen for qgroup if there is already an existing qgroup and then we're trying to create a subvolume for it. [FIX] In that case, we can continue creating the subvolume, although it may lead to qgroup inconsistency, it's not so critical to abort the current transaction. So in this case, we can just ignore the non-critical errors, mostly -EEXIST (there is already a qgroup). Reported-by: syzbot+4d81015bc10889fd12ea@syzkaller.appspotmail.com Fixes: 6ed05643ddb1 ("btrfs: create qgroup earlier in snapshot creation") Signed-off-by: Qu Wenruo Reviewed-by: Filipe Manana --- fs/btrfs/transaction.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 9694a3ca1739..7af9665bebae 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1774,7 +1774,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, btrfs_release_path(path); ret = btrfs_create_qgroup(trans, objectid); - if (ret) { + if (ret && ret != -EEXIST) { btrfs_abort_transaction(trans, ret); goto fail; }