| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20231124075953.1932764-3-yukuai1@huaweicloud.com>
Date: Fri, 24 Nov 2023 15:59:49 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: song@...nel.org, yukuai3@...wei.com, xni@...hat.com
Cc: linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
yukuai1@...weicloud.com, yi.zhang@...wei.com, yangerkun@...wei.com
Subject: [PATCH v2 2/6] md: remove redundant check of 'mddev->sync_thread'
From: Yu Kuai <yukuai3@...wei.com>
The lifetime of sync_thread:
1) Set MD_RECOVERY_NEEDED and wake up daemon thread (by ioctl/sysfs or
other events);
2) Daemon thread woke up, md_check_recovery() found that
MD_RECOVERY_NEEDED is set:
a) try to grab reconfig_mutex;
b) set MD_RECOVERY_RUNNING;
c) clear MD_RECOVERY_NEEDED, and then queue sync_work;
3) md_start_sync() choose sync_action, then register sync_thread;
4) md_do_sync() is done, set MD_RECOVERY_DONE and wake up daemon thread;
5) Daemon thread woke up, md_check_recovery() found that
MD_RECOVERY_DONE is set:
a) try to grab reconfig_mutex;
b) unregister sync_thread;
c) clear MD_RECOVERY_RUNNING and MD_RECOVERY_DONE;
Hence if MD_RECOVERY_RUNNING is not set, mddev->sync_thread must be
NULL, there is no need to judge "mddev->sync_thread == NULL" if
MD_RECOVERY_RUNNING is not set.
Noted that unregister sync_thread(md_reap_sync_thread()) from other
context is wrong and will cause deadlock, for example commit
130443d60b1b ("md: refactor idle/frozen_sync_thread() to fix deadlock").
Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
drivers/md/md.c | 22 +++++++---------------
drivers/md/raid5.c | 6 ++----
2 files changed, 9 insertions(+), 19 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 1701e2fb219f..1d33a39d4f13 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3302,8 +3302,7 @@ static ssize_t new_offset_store(struct md_rdev *rdev,
if (kstrtoull(buf, 10, &new_offset) < 0)
return -EINVAL;
- if (mddev->sync_thread ||
- test_bit(MD_RECOVERY_RUNNING,&mddev->recovery))
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
if (new_offset == rdev->data_offset)
/* reset is always permitted */
@@ -3987,8 +3986,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
*/
rv = -EBUSY;
- if (mddev->sync_thread ||
- test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
mddev->reshape_position != MaxSector ||
mddev->sysfs_active)
goto out_unlock;
@@ -4898,8 +4896,7 @@ static void frozen_sync_thread(struct mddev *mddev)
set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
stop_sync_thread(mddev);
- wait_event(resync_wait, mddev->sync_thread == NULL &&
- !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery));
+ wait_event(resync_wait, !test_bit(MD_RECOVERY_RUNNING, &mddev->recovery));
mutex_unlock(&mddev->sync_mutex);
}
@@ -6388,7 +6385,6 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
mutex_lock(&mddev->open_mutex);
if ((mddev->pers && atomic_read(&mddev->openers) > !!bdev) ||
- mddev->sync_thread ||
test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
pr_warn("md: %s still in use.\n",mdname(mddev));
if (did_freeze) {
@@ -6444,15 +6440,13 @@ static int do_md_stop(struct mddev *mddev, int mode,
md_wakeup_thread_directly(mddev->sync_thread);
mddev_unlock(mddev);
- wait_event(resync_wait, (mddev->sync_thread == NULL &&
- !test_bit(MD_RECOVERY_RUNNING,
- &mddev->recovery)));
+ wait_event(resync_wait, !test_bit(MD_RECOVERY_RUNNING,
+ &mddev->recovery));
mddev_lock_nointr(mddev);
mutex_lock(&mddev->open_mutex);
if ((mddev->pers && atomic_read(&mddev->openers) > !!bdev) ||
mddev->sysfs_active ||
- mddev->sync_thread ||
test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
pr_warn("md: %s still in use.\n",mdname(mddev));
mutex_unlock(&mddev->open_mutex);
@@ -7298,8 +7292,7 @@ static int update_size(struct mddev *mddev, sector_t num_sectors)
* of each device. If num_sectors is zero, we find the largest size
* that fits.
*/
- if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- mddev->sync_thread)
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
return -EBUSY;
if (!md_is_rdwr(mddev))
return -EROFS;
@@ -7336,8 +7329,7 @@ static int update_raid_disks(struct mddev *mddev, int raid_disks)
if (raid_disks <= 0 ||
(mddev->max_disks && raid_disks >= mddev->max_disks))
return -EINVAL;
- if (mddev->sync_thread ||
- test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
test_bit(MD_RESYNCING_REMOTE, &mddev->recovery) ||
mddev->reshape_position != MaxSector)
return -EBUSY;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4207e945e8c8..ec6cb8185207 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7018,10 +7018,8 @@ raid5_store_stripe_size(struct mddev *mddev, const char *page, size_t len)
pr_debug("md/raid: change stripe_size from %lu to %lu\n",
conf->stripe_size, new);
- if (mddev->sync_thread ||
- test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- mddev->reshape_position != MaxSector ||
- mddev->sysfs_active) {
+ if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
+ mddev->reshape_position != MaxSector || mddev->sysfs_active) {
err = -EBUSY;
goto out_unlock;
}
--
2.39.2
Powered by blists - more mailing lists