Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753205AbcDRKtk (ORCPT ); Mon, 18 Apr 2016 06:49:40 -0400 Received: from mail.kernel.org ([198.145.29.136]:34730 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753185AbcDRKti (ORCPT ); Mon, 18 Apr 2016 06:49:38 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, NeilBrown , Zefan Li Subject: [PATCH 3.4 47/92] md/raid1: ensure device failure recorded before write request returns. Date: Mon, 18 Apr 2016 18:45:52 +0800 Message-Id: <1460976397-5688-47-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1460976338-5631-1-git-send-email-lizf@kernel.org> References: <1460976338-5631-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5258 Lines: 145 From: NeilBrown 3.4.112-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit 55ce74d4bfe1b9444436264c637f39a152d1e5ac upstream. When a write to one of the legs of a RAID1 fails, the failure is recorded in the metadata of the other leg(s) so that after a restart the data on the failed drive wont be trusted even if that drive seems to be working again (maybe a cable was unplugged). Similarly when we record a bad-block in response to a write failure, we must not let the write complete until the bad-block update is safe. Currently there is no interlock between the write request completing and the metadata update. So it is possible that the write will complete, the app will confirm success in some way, and then the machine will crash before the metadata update completes. This is an extremely small hole for a racy to fit in, but it is theoretically possible and so should be closed. So: - set MD_CHANGE_PENDING when requesting a metadata update for a failed device, so we can know with certainty when it completes - queue requests that experienced an error on a new queue which is only processed after the metadata update completes - call raid_end_bio_io() on bios in that queue when the time comes. Signed-off-by: NeilBrown Signed-off-by: Zefan Li --- drivers/md/md.c | 1 + drivers/md/raid1.c | 29 ++++++++++++++++++++++++++++- drivers/md/raid1.h | 5 +++++ 3 files changed, 34 insertions(+), 1 deletion(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index a875348..9085ba9 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -7954,6 +7954,7 @@ int rdev_set_badblocks(struct md_rdev *rdev, sector_t s, int sectors, /* Make sure they get written out promptly */ sysfs_notify_dirent_safe(rdev->sysfs_state); set_bit(MD_CHANGE_CLEAN, &rdev->mddev->flags); + set_bit(MD_CHANGE_PENDING, &rdev->mddev->flags); md_wakeup_thread(rdev->mddev->thread); } return rv; diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 189eedb..64d2351c 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1285,6 +1285,7 @@ static void error(struct mddev *mddev, struct md_rdev *rdev) set_bit(Faulty, &rdev->flags); spin_unlock_irqrestore(&conf->device_lock, flags); set_bit(MD_CHANGE_DEVS, &mddev->flags); + set_bit(MD_CHANGE_PENDING, &mddev->flags); printk(KERN_ALERT "md/raid1:%s: Disk failure on %s, disabling device.\n" "md/raid1:%s: Operation continuing on %d devices.\n", @@ -2061,6 +2062,7 @@ static void handle_sync_write_finished(struct r1conf *conf, struct r1bio *r1_bio static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio) { int m; + bool fail = false; for (m = 0; m < conf->raid_disks * 2 ; m++) if (r1_bio->bios[m] == IO_MADE_GOOD) { struct md_rdev *rdev = conf->mirrors[m].rdev; @@ -2073,6 +2075,7 @@ static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio) * narrow down and record precise write * errors. */ + fail = true; if (!narrow_write_error(r1_bio, m)) { md_error(conf->mddev, conf->mirrors[m].rdev); @@ -2084,7 +2087,13 @@ static void handle_write_finished(struct r1conf *conf, struct r1bio *r1_bio) } if (test_bit(R1BIO_WriteError, &r1_bio->state)) close_write(r1_bio); - raid_end_bio_io(r1_bio); + if (fail) { + spin_lock_irq(&conf->device_lock); + list_add(&r1_bio->retry_list, &conf->bio_end_io_list); + spin_unlock_irq(&conf->device_lock); + md_wakeup_thread(conf->mddev->thread); + } else + raid_end_bio_io(r1_bio); } static void handle_read_error(struct r1conf *conf, struct r1bio *r1_bio) @@ -2187,6 +2196,23 @@ static void raid1d(struct mddev *mddev) md_check_recovery(mddev); + if (!list_empty_careful(&conf->bio_end_io_list) && + !test_bit(MD_CHANGE_PENDING, &mddev->flags)) { + LIST_HEAD(tmp); + spin_lock_irqsave(&conf->device_lock, flags); + if (!test_bit(MD_CHANGE_PENDING, &mddev->flags)) { + list_add(&tmp, &conf->bio_end_io_list); + list_del_init(&conf->bio_end_io_list); + } + spin_unlock_irqrestore(&conf->device_lock, flags); + while (!list_empty(&tmp)) { + r1_bio = list_first_entry(&conf->bio_end_io_list, + struct r1bio, retry_list); + list_del(&r1_bio->retry_list); + raid_end_bio_io(r1_bio); + } + } + blk_start_plug(&plug); for (;;) { @@ -2596,6 +2622,7 @@ static struct r1conf *setup_conf(struct mddev *mddev) conf->raid_disks = mddev->raid_disks; conf->mddev = mddev; INIT_LIST_HEAD(&conf->retry_list); + INIT_LIST_HEAD(&conf->bio_end_io_list); spin_lock_init(&conf->resync_lock); init_waitqueue_head(&conf->wait_barrier); diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h index 80ded13..50086cf 100644 --- a/drivers/md/raid1.h +++ b/drivers/md/raid1.h @@ -48,6 +48,11 @@ struct r1conf { * block, or anything else. */ struct list_head retry_list; + /* A separate list of r1bio which just need raid_end_bio_io called. + * This mustn't happen for writes which had any errors if the superblock + * needs to be written. + */ + struct list_head bio_end_io_list; /* queue pending writes to be submitted on unplug */ struct bio_list pending_bio_list; -- 1.9.1