From patchwork Mon Mar 20 02:12:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 13180675 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 C119BC7618A for ; Mon, 20 Mar 2023 02:13:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229593AbjCTCNW (ORCPT ); Sun, 19 Mar 2023 22:13:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbjCTCNV (ORCPT ); Sun, 19 Mar 2023 22:13:21 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB69F5FD1 for ; Sun, 19 Mar 2023 19:13:19 -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-out2.suse.de (Postfix) with ESMTPS id 6D9031F37C for ; Mon, 20 Mar 2023 02:13:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1679278398; 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=9BQ9aESDdebOSMvFa3KOcio9lX7tdJPkSm/sKhbines=; b=ur4516i1+GsRzobYMf9DmuFgdPENyJnShWYbWTsKA6cjZaV4Qa6BJscZ3htwSz7kNvTXbk AxxjjgYM9F3fC66pvUq2U/NBJ3veneamXvnYLUq4GSektAfSHEE8f7lZ2IS0qAdRiWzvfe OOz8Xj5p23f5wJ5Y7cJlmi9QZ6mV374= 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 C514213416 for ; Mon, 20 Mar 2023 02:13:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id CaS8CD3BF2QLPQAAMHmgww (envelope-from ) for ; Mon, 20 Mar 2023 02:13:17 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v3 00/12] btrfs: scrub: use a more reader friendly code to implement scrub_simple_mirror() Date: Mon, 20 Mar 2023 10:12:46 +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] 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 (12): btrfs: scrub: use dedicated super block verification function to scrub one super block btrfs: introduce a new helper to submit 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 | 144 +++- fs/btrfs/bio.h | 20 +- fs/btrfs/file-item.c | 9 +- fs/btrfs/file-item.h | 3 +- fs/btrfs/raid56.c | 2 +- fs/btrfs/scrub.c | 1658 ++++++++++++++++++++++++++++++------------ 6 files changed, 1351 insertions(+), 485 deletions(-)