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 B917DC761A6 for ; Tue, 28 Mar 2023 23:57:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229711AbjC1X5F (ORCPT ); Tue, 28 Mar 2023 19:57:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38052 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229862AbjC1X5A (ORCPT ); Tue, 28 Mar 2023 19:57:00 -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 393912D55 for ; Tue, 28 Mar 2023 16:56:42 -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 C3D5A1FDAC for ; Tue, 28 Mar 2023 23:56:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1680047797; 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=Xz15HjwyuXGDkt3qOlJPF5gjrHYjOV8HDE/QyvECB0w=; b=AWIs109AWgkHv5Tep1+IbhPRRCrLRqWdy/KENjkEuBxCHSKbo3eT/rmH550bAZMLxWTSad szp2a31O3CgITJnz0FTaEEK+JK2GCvp3uIAmikfNvudz3QFa61sP3ksw4j1fcAB6WkTf37 NBLJI1fDLg4jUskMPTTGvLp94sy+O4M= 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 39E5113488 for ; Tue, 28 Mar 2023 23:56:37 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id tXo7A7V+I2T4eQAAMHmgww (envelope-from ) for ; Tue, 28 Mar 2023 23:56:37 +0000 From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH v7 00/13] btrfs: scrub: use a more reader friendly code to implement scrub_simple_mirror() Date: Wed, 29 Mar 2023 07:56:07 +0800 Message-Id: X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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] v7: - Fix a bug that scrub_stripe::extent_sector_bitmap is not cleared Exposed during my development for RAID56 new scrub code. Extent_sector_bitmap indicates whether the sector is utilized by any extent. If that bitmap is not cleared before running the next stripe, we can treat unused sectors as NODATASUM data. This is not a big deal for non-RAID56 profiles, as they skip empty stripe through other methods. But can be very problematic for RAID56, as they need to scrub data stripes then P/Q stripes. Such inherited bitmap makes RAID56 to scrub all those unused full stripes and greatly slow down the scrub. 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. - Cleanup on RAID56 path Already done in the github repo. Still needs to do some patch split as the cleanup itself is twice the size of the submitted series already. 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 | 1662 ++++++++++++++++++++++++++++++------------ 6 files changed, 1378 insertions(+), 485 deletions(-) -- 2.39.2