From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F59BC43334 for ; Thu, 30 Jun 2022 15:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235559AbiF3PKo (ORCPT ); Thu, 30 Jun 2022 11:10:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235606AbiF3PKn (ORCPT ); Thu, 30 Jun 2022 11:10:43 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43BA32AE26; Thu, 30 Jun 2022 08:10:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D6CEA60ABF; Thu, 30 Jun 2022 15:10:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E11E2C3411E; Thu, 30 Jun 2022 15:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656601841; bh=BkGW5Xjs92vJQ/LaobdSoLoAjMgbz56UiKiJi3QMEIQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AhCGqBvaW0/nE+gYgMHZ/aKvHmjCAa3UTHne7qEoR+zs6E+RTxa30WmGOsybW9u7l atYHAjgC80CTUs7eAimHVg6IDbRD7BqinVJ/LBi6zqawSQUzQf8b7ioE7RO4/1h2CZ 3zAsfRJw13zQAircfNkbkAzvRLYxPPxfAKiqKBiZtqPIqZldo46gmq+qBKQxzUeDLj Me061AtQAg41JIYobeALsWmQQUYedPVQ8zcvTEywpO7SQyV3z9oXM5BtiiSM5XNG3P 0B0hwPJhNIRkRFdb/R01AwoskqHyJ9mp/bkTyQ81riE0d83TUlWrK0L53YTtpBUAi1 gRU35thBg39Cw== Date: Thu, 30 Jun 2022 16:10:38 +0100 From: Filipe Manana To: Dominique MARTINET Cc: Nikolay Borisov , Jens Axboe , io-uring@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: Re: read corruption with qemu master io_uring engine / linux master / btrfs(?) Message-ID: <20220630151038.GA459423@falcondesktop> References: <20220629153710.GA379981@falcondesktop> <20220630104536.GA434846@falcondesktop> <20220630125124.GA446657@falcondesktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, Jun 30, 2022 at 10:08:18PM +0900, Dominique MARTINET wrote: > Filipe Manana wrote on Thu, Jun 30, 2022 at 01:51:24PM +0100: > > > Please ask if there's any infos I could get you. > > > > Ok, maybe it's page fault related or there's something else besides page faults > > involved. > > > > Can you dump the subvolume tree like this: > > > > btrfs inspect-internal dump-tree -t 5 /dev/sda 2>&1 | xz -9 > dump.xz > > > > Here the 5 is the ID of the default subvolume. If the test file is on > > a different subvolume, you'll need to replace 5 with the subvolume's ID. > > Sure thing. > > It's 2MB compressed: > https://gaia.codewreck.org/local/tmp/dump-tree.xz Ok, the file has a mix of compressed and non-compressed extents. This may prevent the short reads (not tested yet): diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 7a54f964ff37..42fb56ed0021 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7684,7 +7684,7 @@ static int btrfs_dio_iomap_begin(struct inode *inode, loff_t start, if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) || em->block_start == EXTENT_MAP_INLINE) { free_extent_map(em); - ret = -ENOTBLK; + ret = (flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOTBLK; goto unlock_err; } Can you give it a try? Thanks. > > > > This is just to look at the file extent layout. > > Also, then tell me what's the inode number of the file (or just its name, > > and I'll find out its inode number), and an example file offset and read > > length that triggers a short read, so that I know where to look at. > > There's just a single file in that subvolume, inode 257 > > > And btw, that dump-tree command will dump all file names, directory names > > and xattr names and values (if they are human readable) - so if privacy is > > a concern here, just pass --hide-names to the dump-tree command. > > (thanks for the warning) > -- > Dominique