From patchwork Thu Jul 20 22:52:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boris Burkov X-Patchwork-Id: 13321155 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 D56CFEB64DD for ; Thu, 20 Jul 2023 22:55:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229785AbjGTWzD (ORCPT ); Thu, 20 Jul 2023 18:55:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229618AbjGTWzB (ORCPT ); Thu, 20 Jul 2023 18:55:01 -0400 Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1EDA270B for ; Thu, 20 Jul 2023 15:54:49 -0700 (PDT) Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id BFEB25C00F0; Thu, 20 Jul 2023 18:54:37 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Thu, 20 Jul 2023 18:54:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bur.io; h=cc :content-transfer-encoding:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:sender:subject:subject:to:to; s=fm1; t=1689893677; x= 1689980077; bh=M10GRgW8Oo/CA1itNOSle6w3dntzCKyqXOPnbe/r0Ao=; b=A pZ/EMcK3gSWX76x5iSFC3NY1AVv/5VClnW881gwAXCas71MreAZhhweAKXcv17NR 2YLgDYuUtc2QXhvEFWzNZ5kft0RdqywvAfkmqAjZ2FGIHbzh0YFbd0U+zFF/AwGz 9XcYXFLow8ed40tVVYoATZ2yO6DMkA1gPYoIUoUlV8WSiW5YHr5bwbdVEsAw9Aod S2Z0CFiijpmfzJW52xNRlFwl5ipqVVa6fJ/SbqvBygj+HMqMYieqiQ1RCQh2V0Qh a/QglJ+0loasgMndjgQFrEpqrzBy94Ym8I7Bg3VY5/vzmEq1la0YMaDyQsC7lHvM gHkuk1G9Cyr172Z0Tdr3g== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:date:feedback-id:feedback-id:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to:x-me-proxy:x-me-proxy:x-me-sender :x-me-sender:x-sasl-enc; s=fm3; t=1689893677; x=1689980077; bh=M 10GRgW8Oo/CA1itNOSle6w3dntzCKyqXOPnbe/r0Ao=; b=Xc6uY8nnbHXxBc0jw fPdKHk9LEe7SATjyPZ/itx38CZKKCimG+m/jq1vcfGx+1YmIZc5b+XadH5PqUQOP 85trWD30xIpozawgSGBTGMahoDi/f0wJ8h0CS7hGKpnpvDBaBYybSWRthh7fA2cv p1flkSqLM8CzAnb3UbAAhEgWUBQpZOB1XjVq2E0EREpAZGJxR9XOa29QmMqipViY tg7CuV8FGWhi3MgCMW28mubG9PIpmldcaS0exCQD0a0AEvKV+OQW0u2lboF/NcLu n1SXwwEdEoS+8lqMO8WyikZAJe04H44YhMxXcL5IZFxovIkkh5inmuATPNxJTqRg W505w== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedviedrhedugdduhecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhephffvufffkffojghfggfgsedtkeertd ertddtnecuhfhrohhmpeeuohhrihhsuceuuhhrkhhovhcuoegsohhrihhssegsuhhrrdhi oheqnecuggftrfgrthhtvghrnhepieeuffeuvdeiueejhfehiefgkeevudejjeejffevvd ehtddufeeihfekgeeuheelnecuvehluhhsthgvrhfuihiivgepvdenucfrrghrrghmpehm rghilhhfrhhomhepsghorhhishessghurhdrihho X-ME-Proxy: Feedback-ID: i083147f8:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 20 Jul 2023 18:54:37 -0400 (EDT) From: Boris Burkov To: linux-btrfs@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v2 07/20] btrfs: flush reservations during quota disable Date: Thu, 20 Jul 2023 15:52:35 -0700 Message-ID: X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org The following sequence: enable simple quotas do some writes reserve space create ordered_extent release rsv (store rsv_bytes in OE, mark QGROUP_RESERVED bits) disable quotas enable simple quotas set qgroup rsv to 0 on all subvols ordered_extent finishes create delayed ref with rsv_bytes from before run delayed ref record_simple_quota_delta free rsv_bytes (0 -> -rsv_delta) results in us reliably underflowing the subvolume's qgroup rsv counter, because disabling/re-enabling quotas toggles reservation counters down to 0, but does not remove other file system state which represents successful acquisition of qgroup rsv space. Specifically metadata rsv counters on the root object and rsv_bytes on ordered_extent objects that have released their reservation as well as the corresponding QGROUP_RESERVED extent bits. Normal qgroups gets away with this, I believe because it forces more work to happen on transaction commit, but I am not certain it is totally safe from the ordered_extent/leaked extent bit variant. Simple quotas hits this reliably. The intent of the fix is to make disable take the time to clear that external to qgroups state as well: after flipping off the quota bit on fs_info, flush delalloc and ordered extents, clearing the extent bits along the way. This makes it so there are no ordered extents or meta prealloc hanging around from the first enablement period during the second. Signed-off-by: Boris Burkov Reviewed-by: Josef Bacik --- fs/btrfs/qgroup.c | 47 ++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 44 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index 558f66994667..18f521716e8d 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -1248,6 +1248,40 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info, return ret; } +/* + * It is possible to have outstanding ordered extents + * which reserved bytes before we disabled. We need to fully flush + * delalloc, ordered extents, and a commit to ensure that + * we don't leak such reservations, only to have them come back + * if we re-enable. + * + * i.e.: + * enable simple quotas + * reserve space + * release it, store rsv_bytes in OE + * disable quotas + * enable simple quotas (qgroup rsv are all 0) + * OE finishes + * run delayed refs + * free rsv_bytes, resulting in miscounting or even underflow + */ +static int flush_reservations(struct btrfs_fs_info *fs_info) +{ + struct btrfs_trans_handle *trans; + int ret; + + ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false); + if (ret) + return ret; + btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1); + trans = btrfs_join_transaction(fs_info->tree_root); + if (IS_ERR(trans)) + return PTR_ERR(trans); + btrfs_commit_transaction(trans); + + return ret; +} + int btrfs_quota_disable(struct btrfs_fs_info *fs_info) { struct btrfs_root *quota_root; @@ -1292,6 +1326,10 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags); btrfs_qgroup_wait_for_completion(fs_info, false); + ret = flush_reservations(fs_info); + if (ret) + goto out; + /* * 1 For the root item * @@ -1353,7 +1391,7 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info) if (ret && trans) btrfs_end_transaction(trans); else if (trans) - ret = btrfs_end_transaction(trans); + ret = btrfs_commit_transaction(trans); mutex_unlock(&fs_info->cleaner_mutex); return ret; @@ -3957,8 +3995,11 @@ static int __btrfs_qgroup_release_data(struct btrfs_inode *inode, int trace_op = QGROUP_RELEASE; int ret; - if (btrfs_qgroup_mode(inode->root->fs_info) == BTRFS_QGROUP_MODE_DISABLED) - return 0; + if (btrfs_qgroup_mode(inode->root->fs_info) == BTRFS_QGROUP_MODE_DISABLED) { + extent_changeset_init(&changeset); + return clear_record_extent_bits(&inode->io_tree, start, start + len - 1, + EXTENT_QGROUP_RESERVED, &changeset); + } /* In release case, we shouldn't have @reserved */ WARN_ON(!free && reserved);