From patchwork Tue Jun 23 23:23:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 11622085 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EFC8D912 for ; Tue, 23 Jun 2020 23:23:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E20562098B for ; Tue, 23 Jun 2020 23:23:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388092AbgFWXX6 (ORCPT ); Tue, 23 Jun 2020 19:23:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:37738 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387495AbgFWXX5 (ORCPT ); Tue, 23 Jun 2020 19:23:57 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id F3DB8AECE for ; Tue, 23 Jun 2020 23:23:55 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v5 0/3] btrfs: allow btrfs_truncate_block() to fallback to nocow for data space reservation Date: Wed, 24 Jun 2020 07:23:49 +0800 Message-Id: <20200623232352.668681-1-wqu@suse.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Before this patch, btrfs_truncate_block() never checks the NODATACOW bit, thus when we run out of data space, we can return ENOSPC for truncate for NODATACOW inode. This patchset will address this problem by doing the same behavior as buffered write to address it. Changelog: v2: - Rebased to misc-next Only one minor conflict in ctree.h v3: - Added two new patches - Refactor check_can_nocow() Since the introduction of nowait, check_can_nocow() are in fact split into two usage patterns: check_can_nocow(nowait = false) with btrfs_drew_write_unlock(), and single check_can_nocow(nowait = true). Refactor them into two functions: start_nocow_check() paired with end_nocow_check(), and single try_nocow_check(). With comment added. - Rebased to latest misc-next - Added btrfs_assert_drew_write_locked() for btrfs_end_nocow_check() This is a little concerning one, as it's in the hot path of buffered write. It has percpu_counter_sum() called in that hot path, causing obvious performance drop for CONFIG_BTRFS_DEBUG build. Not sure if the assert is worthy since there aren't any other users. v4: - Rebased to latest misc-next - Comment update to follow the relaxed kernel-doc format - Re-order the patches So the fix comes first, then refactors. - Naming updates for the refactor patch Now the exported pair is btrfs_check_nocow_lock() and btrfs_check_nocow_unlock(). - Remove the btrfs_assert_drew_write_lock() It's extremely slow for btrfs/187, and we only have two call sites so far, thus it's not really worthy. v5: - Fix a stupid bug that check_nocow_nolock() passes wrong bool - Update the comment for btrfs_check_nocow_lock() as there is no "nowait" parameter anymore Qu Wenruo (3): btrfs: allow btrfs_truncate_block() to fallback to nocow for data space reservation btrfs: add comments for btrfs_check_can_nocow() and can_nocow_extent() btrfs: refactor btrfs_check_can_nocow() into two variants fs/btrfs/ctree.h | 3 +++ fs/btrfs/file.c | 61 +++++++++++++++++++++++++++++++++++----------- fs/btrfs/inode.c | 63 +++++++++++++++++++++++++++++++++++++++++------- 3 files changed, 104 insertions(+), 23 deletions(-)