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a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711320553; c=relaxed/simple; bh=yVUsKV4jgxvtvm1H6E8T9TK0qKFypGddsw3+FQLzm+g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hefjqB7FEQx7fTqHJdAHQRjm6QtSRnOHeEpdZPej91q5FfFyc/MAbctupzJKO/3sJdC1kf3pzCWHk1JIYLIgZ1JmQLz3TSD78PawqAA6AUnVEMBEjdoJ0QrCVFZzIaVpilD9hyA0TMbPPXo938IljOQarEuZnVXaSm4ImezncwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ChUnC/Ho; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 10787C43394; Sun, 24 Mar 2024 22:49:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711320551; bh=yVUsKV4jgxvtvm1H6E8T9TK0qKFypGddsw3+FQLzm+g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ChUnC/HoTmVmlLpQW1vULMR1Mi9Xfx3yxf1TgY5gjkPyMqIpcUaZ3QpysZiLf3bn4 7JSLvLKzb1by3tipCi0I7M3/JVT5VBUMPAHUdTcLW8FdtaffAweCMJrmo18g+mg6D9 E3vi/iJrwWQp9CZ7veQNNsiBOJnLxDIYNFWhY8Xw2QQu9u4p72smatfiZXhiMFUpdE pjRJ3G1gJMsWuNrA3uZwKrAPCeH1X3se0fWYbFT6jraqaXXpPhUEMKsl91sPP/wkOl X4Iou8EO930RK229U5ZyeH1ZlT1MJYRR/Th8Ato1fd+oAl4njrKp6Fa02K5cXyHUYy pWqHPCIkdP+cQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yu Kuai , Song Liu , Sasha Levin Subject: [PATCH 6.7 112/713] md: remove flag RemoveSynchronized Date: Sun, 24 Mar 2024 18:37:18 -0400 Message-ID: <20240324224720.1345309-113-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324224720.1345309-1-sashal@kernel.org> References: <20240324224720.1345309-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Yu Kuai [ Upstream commit c891f1fd90e66e584bb1353e1859cef7c9eb36f8 ] rcu is not used correctly here, because synchronize_rcu() is called before replacing old value, for example: remove_and_add_spares // other path synchronize_rcu // called before replacing old value set_bit(RemoveSynchronized) rcu_read_lock() rdev = conf->mirros[].rdev pers->hot_remove_disk conf->mirros[].rdev = NULL; if (!test_bit(RemoveSynchronized)) synchronize_rcu /* * won't be called, and won't wait * for concurrent readers to be done. */ // access rdev after remove_and_add_spares() rcu_read_unlock() Fortunately, there is a separate rcu protection to prevent such rdev to be freed: md_kick_rdev_from_array //other path rcu_read_lock() rdev = conf->mirros[].rdev list_del_rcu(&rdev->same_set) rcu_read_unlock() /* * rdev can be removed from conf, but * rdev won't be freed. */ synchronize_rcu() free rdev Hence remove this useless flag and prepare to remove rcu protection to access rdev from 'conf'. Signed-off-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20231125081604.3939938-2-yukuai1@huaweicloud.com Stable-dep-of: 257ac239ffcf ("md/raid1: fix choose next idle in read_balance()") Signed-off-by: Sasha Levin --- drivers/md/md-multipath.c | 9 --------- drivers/md/md.c | 37 ++++++------------------------------- drivers/md/md.h | 5 ----- drivers/md/raid1.c | 9 --------- drivers/md/raid10.c | 9 --------- drivers/md/raid5.c | 9 --------- 6 files changed, 6 insertions(+), 72 deletions(-) diff --git a/drivers/md/md-multipath.c b/drivers/md/md-multipath.c index d22276870283d..aa77133f31887 100644 --- a/drivers/md/md-multipath.c +++ b/drivers/md/md-multipath.c @@ -258,15 +258,6 @@ static int multipath_remove_disk(struct mddev *mddev, struct md_rdev *rdev) goto abort; } p->rdev = NULL; - if (!test_bit(RemoveSynchronized, &rdev->flags)) { - synchronize_rcu(); - if (atomic_read(&rdev->nr_pending)) { - /* lost the race, try later */ - err = -EBUSY; - p->rdev = rdev; - goto abort; - } - } err = md_integrity_register(mddev); } abort: diff --git a/drivers/md/md.c b/drivers/md/md.c index b2f27ac51bfb6..99b60d37114c4 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9314,44 +9314,19 @@ static int remove_and_add_spares(struct mddev *mddev, struct md_rdev *rdev; int spares = 0; int removed = 0; - bool remove_some = false; if (this && test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) /* Mustn't remove devices when resync thread is running */ return 0; rdev_for_each(rdev, mddev) { - if ((this == NULL || rdev == this) && - rdev->raid_disk >= 0 && - !test_bit(Blocked, &rdev->flags) && - test_bit(Faulty, &rdev->flags) && - atomic_read(&rdev->nr_pending)==0) { - /* Faulty non-Blocked devices with nr_pending == 0 - * never get nr_pending incremented, - * never get Faulty cleared, and never get Blocked set. - * So we can synchronize_rcu now rather than once per device - */ - remove_some = true; - set_bit(RemoveSynchronized, &rdev->flags); - } - } - - if (remove_some) - synchronize_rcu(); - rdev_for_each(rdev, mddev) { - if ((this == NULL || rdev == this) && - (test_bit(RemoveSynchronized, &rdev->flags) || - rdev_removeable(rdev))) { - if (mddev->pers->hot_remove_disk( - mddev, rdev) == 0) { - sysfs_unlink_rdev(mddev, rdev); - rdev->saved_raid_disk = rdev->raid_disk; - rdev->raid_disk = -1; - removed++; - } + if ((this == NULL || rdev == this) && rdev_removeable(rdev) && + !mddev->pers->hot_remove_disk(mddev, rdev)) { + sysfs_unlink_rdev(mddev, rdev); + rdev->saved_raid_disk = rdev->raid_disk; + rdev->raid_disk = -1; + removed++; } - if (remove_some && test_bit(RemoveSynchronized, &rdev->flags)) - clear_bit(RemoveSynchronized, &rdev->flags); } if (removed && mddev->kobj.sd) diff --git a/drivers/md/md.h b/drivers/md/md.h index ade83af123a22..8d881cc597992 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -190,11 +190,6 @@ enum flag_bits { * than other devices in the array */ ClusterRemove, - RemoveSynchronized, /* synchronize_rcu() was called after - * this device was known to be faulty, - * so it is safe to remove without - * another synchronize_rcu() call. - */ ExternalBbl, /* External metadata provides bad * block management for a disk */ diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index e138922d51292..6bd42ccbea9c4 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -1863,15 +1863,6 @@ static int raid1_remove_disk(struct mddev *mddev, struct md_rdev *rdev) goto abort; } p->rdev = NULL; - if (!test_bit(RemoveSynchronized, &rdev->flags)) { - synchronize_rcu(); - if (atomic_read(&rdev->nr_pending)) { - /* lost the race, try later */ - err = -EBUSY; - p->rdev = rdev; - goto abort; - } - } if (conf->mirrors[conf->raid_disks + number].rdev) { /* We just removed a device that is being replaced. * Move down the replacement. We drain all IO before diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index b7b0a573e7f8b..6e828a6aa0b0a 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2247,15 +2247,6 @@ static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev) goto abort; } *rdevp = NULL; - if (!test_bit(RemoveSynchronized, &rdev->flags)) { - synchronize_rcu(); - if (atomic_read(&rdev->nr_pending)) { - /* lost the race, try later */ - err = -EBUSY; - *rdevp = rdev; - goto abort; - } - } if (p->replacement) { /* We must have just cleared 'rdev' */ p->rdev = p->replacement; diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 6fe334bb954ab..f03e4231bec11 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -8241,15 +8241,6 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev) goto abort; } *rdevp = NULL; - if (!test_bit(RemoveSynchronized, &rdev->flags)) { - lockdep_assert_held(&mddev->reconfig_mutex); - synchronize_rcu(); - if (atomic_read(&rdev->nr_pending)) { - /* lost the race, try later */ - err = -EBUSY; - rcu_assign_pointer(*rdevp, rdev); - } - } if (!err) { err = log_modify(conf, rdev, false); if (err) -- 2.43.0