From patchwork Tue Mar 28 08:52:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 13190678 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 DB969C76196 for ; Tue, 28 Mar 2023 08:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230376AbjC1IxS (ORCPT ); Tue, 28 Mar 2023 04:53:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbjC1IxR (ORCPT ); Tue, 28 Mar 2023 04:53:17 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 407AB40F8 for ; Tue, 28 Mar 2023 01:53:16 -0700 (PDT) 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-out1.suse.de (Postfix) with ESMTPS id EBF1D21835 for ; Tue, 28 Mar 2023 08:53:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1679993594; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=7JXHFZ9NPbTHg93g8dZs24NSiEc3lfy14LKQUgNP/qA=; b=Qphs8Eyf6cI/KZrVrDOjrQUOpStz5tSQadVgQUrpMu9EJlSxJMYPek0QQDWLEDlIjLKuLi 0b5deKobIca1gee5CgmYMNWqyLdkQkdCblpFz9/Vm3euVLiz5d361JHLavoVz9xjaxeiCc 9kgCp4E5EpNsYJfShK9O17CQAZTUpw4= 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 5C1EF1390B for ; Tue, 28 Mar 2023 08:53:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id Qlg1C/qqImRBMwAAMHmgww (envelope-from ) for ; Tue, 28 Mar 2023 08:53:14 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v6 00/13] btrfs: scrub: use a more reader friendly code to implement scrub_simple_mirror() Date: Tue, 28 Mar 2023 16:52:44 +0800 Message-Id: X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This series can be found in my github repo: https://github.com/adam900710/linux/tree/scrub_stripe It's recommended to fetch from the repo, as our misc-next seems to change pretty rapidly. [Changelog] v6: - Fix a bug in zoned block group repair Exposed during my development for RAID56 new scrub code. There is a bug that we may use @stripe to determine if we need to queue a block group for repair. But @stripe is the last stripe we checked, it may not have any error. The correct way is to go through all the stripes and queue the repair if we found any error. v5: - Fix a bug that unconditionally repairs a zoned block group Only trigger the repair if we had any initial read failure Huge thanks to Johannes for the initial ZNS tests. v4: - Add a dedicated patch to add btrfs_bio::fs_info Along with dedicated allocator for scrub btrfs bios. The dedicated allocator is due to the fact that scrub and regular btrfs bios have very different mandatory members (fs_info vs inode + file_offset). For now I believe a different allocator would be better. - Some code style change * No more single letter temporray structure copied from old scrub code * Use "for (int i = 0; ...)" when possible * Some new lines fixes * Extra brackets for tenrary operators * A new macro for (BTRFS_STRIPE_LEN >> PAGE_SHIFT) * Use enum for scrub_stripe::state bit flags * Use extra brackets for double shifting * Use explicit != 0 or == 0 comparing memcmp() results * Remove unnecessary ASSERT()s after btrfs_bio allocation v3: - Add a dedicated @fs_info member for btrfs_bio Unfortunately although we have a 32 bytes hole between @end_io_work and @bio, compiler still choose not to use that hole for whatever reasons. Thus this would increase the size of btrfs_bio by 4 bytes. - Rebased to lastest misc-next - Fix various while space error not caught by btrfs-workflow v2: - Use batched scrub_stripe submission This allows much better performance compared to the old scrub code - Add scrub specific bio layer helpers This makes the scrub code to be completely rely on logical bytenr + mirror_num. [PROBLEMS OF OLD SCRUB] - Too many delayed jumps, making it hard to read Even starting from scrub_simple_mirror(), we have the following functions: scrub_extent() | v scrub_sectors() | v scrub_add_sector_to_rd_bio() | endio function v scrub_bio_end_io() | delayed work v scrub_bio_end_io_worker() | v scrub_block_complete() | v scrub_handle_errored_blocks() | v scrub_recheck_block() | v scrub_repair_sector_from_good_copy() Not to mention the hidden jumps in certain branches. - IOPS inefficient for fragmented extents The real block size of scrub read is between 4K and 128K. If the extents are not adjacent, the blocksize drops to 4K and would be an IOPS disaster. - All hardcoded to do the logical -> physical mapping by scrub itself No usage of any existing bio facilities. And even implemented a RAID56 recovery wrapper. [NEW SCRUB_STRIPE BASED SOLUTION] - Overall streamlined code base queue_scrub_stripe() | v scrub_find_fill_first_stripe() | v done Or queue_scrub_stripe() | v flush_scrub_stripes() | v scrub_submit_initial_read() | endio function v scrub_read_endio() | delayed work v scrub_stripe_read_repair_worker() | v scrub_verify_one_stripe() | v scrub_stripe_submit_repair_read() | v scrub_write_sectors() | v scrub_stripe_report_errors() Only one endio and delayed work, all other work are properly done in a sequential workflow. - Always read in 64KiB block size The real blocksize of read starts at 64KiB, and ends at 512K. This already results a better performance even for the worst case: With patchset: 404.81MiB/s Without patchset: 369.30MiB/s Around 10% performance improvement on an SATA SSD. - All logical bytenr/mirror_num based read and write With the new single stripe fast path in btrfs_submit_bio(), scrub can reuse most of the bio layer code, result much simpler scrub code. [TODO] - More testing on zoned devices Now the patchset can already pass all scrub/replace groups with regular devices. - More cleanup on RAID56 path Now RAID56 still uses some old facility, resulting things like scrub_sector and scrub_bio can not be fully cleaned up. Qu Wenruo (13): btrfs: scrub: use dedicated super block verification function to scrub one super block btrfs: introduce a new allocator for scrub specific btrfs_bio btrfs: introduce a new helper to submit read bio for scrub btrfs: introduce a new helper to submit write bio for scrub btrfs: scrub: introduce the structure for new BTRFS_STRIPE_LEN based interface btrfs: scrub: introduce a helper to find and fill the sector info for a scrub_stripe btrfs: scrub: introduce a helper to verify one metadata btrfs: scrub: introduce a helper to verify one scrub_stripe btrfs: scrub: introduce the main read repair worker for scrub_stripe btrfs: scrub: introduce a writeback helper for scrub_stripe btrfs: scrub: introduce error reporting functionality for scrub_stripe btrfs: scrub: introduce the helper to queue a stripe for scrub btrfs: scrub: switch scrub_simple_mirror() to scrub_stripe infrastructure fs/btrfs/bio.c | 165 ++++- fs/btrfs/bio.h | 22 +- fs/btrfs/file-item.c | 9 +- fs/btrfs/file-item.h | 3 +- fs/btrfs/raid56.c | 2 +- fs/btrfs/scrub.c | 1661 ++++++++++++++++++++++++++++++------------ 6 files changed, 1377 insertions(+), 485 deletions(-)