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 50D97C433EF for ; Mon, 28 Mar 2022 13:17:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243086AbiC1NTe (ORCPT ); Mon, 28 Mar 2022 09:19:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243087AbiC1NTe (ORCPT ); Mon, 28 Mar 2022 09:19:34 -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 1A08C5E147 for ; Mon, 28 Mar 2022 06:17:53 -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 B43C061011 for ; Mon, 28 Mar 2022 13:17:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3098C004DD; Mon, 28 Mar 2022 13:17:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648473472; bh=f8TCbSSlO6THfm18iQE0Dj4jY1GCKECJzfO9iKwr3Os=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fwF7jZnD7Wa/Z0zGct7blp/IK7LPrQHM9EeKbpnRnbILe3b0rPSgYXe2MDp2ENbmR mpL/eu11djLjnAJ6s3Y/iz8MDw/TbvUIlkxhTlrlvObrnAMgXf987DPh2JZ+Qj4+6N 1pxLMf2Bg3XBT+LG+X+oIYIZaPChV4qzvzZISC/bP7QY3Q0F2LUS0Ay0xRSMZ0vb3N 8i4F0domyMnkPR7ncDNqs+6o4ydGqNewkfpd1hvbGNMIgKils9/8DNuQJEHnDFOSvO vJHsDr9Q8mEcx7ktqEtmmc1QMZiD2artSNmePjWtFG3X3DTODURDHsX5Kh39/gbUj8 6QIG/LM1riwnA== Date: Mon, 28 Mar 2022 14:17:49 +0100 From: Filipe Manana To: Naohiro Aota Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] btrfs: fix outstanding extents calculation Message-ID: References: <06cc127b5d3c535917e90fbdce0534742dcde478.1648470587.git.naohiro.aota@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, Mar 28, 2022 at 02:08:30PM +0100, Filipe Manana wrote: > On Mon, Mar 28, 2022 at 09:32:05PM +0900, Naohiro Aota wrote: > > Running generic/406 causes the following WARNING in btrfs_destroy_inode() > > which tells there is outstanding extents left. > > I can't trigger the warning with generic/406. > Any special setup or config to trigger it? > > The change looks fine to me, however I'm curious why this isn't triggered > with generic/406, nor anyone else reported it before, since the test is > fully deterministic. Also the subject "btrfs: fix outstanding extents calculation" is confusing, as the problem is not in the outstanding extents calculation code, but rather not releasing delalloc by the correct amount in a specific code path. So something like "btrfs: release correct delalloc amount in direct IO write path" would be more correct and specific. > > Thanks. > > > > > In btrfs_get_blocks_direct_write(), we reserve a temporary outstanding > > extents with btrfs_delalloc_reserve_metadata() (or indirectly from > > btrfs_delalloc_reserve_space(()). We then release the outstanding extents > > with btrfs_delalloc_release_extents(). However, the "len" can be modified > > in the CoW case, which releasing fewer outstanding extents than expected. > > > > Fix it by calling btrfs_delalloc_release_extents() for the original length. > > > > ------------[ cut here ]------------ > > WARNING: CPU: 0 PID: 757 at fs/btrfs/inode.c:8848 btrfs_destroy_inode+0x1e6/0x210 [btrfs] > > Modules linked in: btrfs blake2b_generic xor lzo_compress > > lzo_decompress raid6_pq zstd zstd_decompress zstd_compress xxhash zram > > zsmalloc > > CPU: 0 PID: 757 Comm: umount Not tainted 5.17.0-rc8+ #101 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS d55cb5a 04/01/2014 > > RIP: 0010:btrfs_destroy_inode+0x1e6/0x210 [btrfs] > > Code: fe ff ff 0f 0b e9 d6 fe ff ff 0f 0b 48 83 bb e0 01 00 00 00 0f 84 > > 65 fe ff ff 0f 0b 48 83 bb 78 ff ff ff 00 0f 84 63 fe ff ff <0f> 0b 48 > > 83 bb 70 ff ff ff 00 0f 84 61 fe ff ff 0f 0b e9 5a fe ff > > RSP: 0018:ffffc9000327bda8 EFLAGS: 00010206 > > RAX: 0000000000000000 RBX: ffff888100548b78 RCX: 0000000000000000 > > RDX: 0000000000026900 RSI: 0000000000000000 RDI: ffff888100548b78 > > RBP: ffff888100548940 R08: 0000000000000000 R09: ffff88810b48aba8 > > R10: 0000000000000001 R11: ffff8881004eb240 R12: ffff88810b48a800 > > R13: ffff88810b48ec08 R14: ffff88810b48ed00 R15: ffff888100490c68 > > FS: 00007f8549ea0b80(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f854a09e733 CR3: 000000010a2e9003 CR4: 0000000000370eb0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > > > destroy_inode+0x33/0x70 > > dispose_list+0x43/0x60 > > evict_inodes+0x161/0x1b0 > > generic_shutdown_super+0x2d/0x110 > > kill_anon_super+0xf/0x20 > > btrfs_kill_super+0xd/0x20 [btrfs] > > deactivate_locked_super+0x27/0x90 > > cleanup_mnt+0x12c/0x180 > > task_work_run+0x54/0x80 > > exit_to_user_mode_prepare+0x152/0x160 > > syscall_exit_to_user_mode+0x12/0x30 > > do_syscall_64+0x42/0x80 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > RIP: 0033:0x7f854a000fb7 > > > > Fixes: f0bfa76a11e9 ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range") > > CC: stable@vger.kernel.org # 5.17 > > Signed-off-by: Naohiro Aota > > --- > > fs/btrfs/inode.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > > index c7b15634fe70..5c0c54057921 100644 > > --- a/fs/btrfs/inode.c > > +++ b/fs/btrfs/inode.c > > @@ -7409,6 +7409,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map, > > u64 block_start, orig_start, orig_block_len, ram_bytes; > > bool can_nocow = false; > > bool space_reserved = false; > > + u64 prev_len; > > int ret = 0; > > > > /* > > @@ -7436,6 +7437,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map, > > can_nocow = true; > > } > > > > + prev_len = len; > > if (can_nocow) { > > struct extent_map *em2; > > > > @@ -7465,8 +7467,6 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map, > > goto out; > > } > > } else { > > - const u64 prev_len = len; > > - > > /* Our caller expects us to free the input extent map. */ > > free_extent_map(em); > > *map = NULL; > > @@ -7497,7 +7497,7 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map, > > * We have created our ordered extent, so we can now release our reservation > > * for an outstanding extent. > > */ > > - btrfs_delalloc_release_extents(BTRFS_I(inode), len); > > + btrfs_delalloc_release_extents(BTRFS_I(inode), prev_len); > > > > /* > > * Need to update the i_size under the extent lock so buffered > > -- > > 2.35.1 > >