From: Yu Kuai yukuai3@huawei.com
mainline inclusion from mainline-v6.7-rc1 commit db5e653d7c9fae8ed61da58ab5e9a8db2cd61a2b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8T02O
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Before this patch, for read-write array:
1) md_check_recover() found that something need to be done, and it'll try to grab 'reconfig_mutex'. The case that md_check_recover() need to do something: - array is not suspend; - super_block need to be updated; - 'MD_RECOVERY_NEEDED' or 'MD_RECOVERY_DONE' is set; - unusual case related to safemode;
2) if 'MD_RECOVERY_RUNNING' is not set, and 'MD_RECOVERY_NEEDED' is set, md_check_recover() will try to choose a sync action, and then queue a work md_start_sync().
3) md_start_sync() register sync_thread;
After this patch,
1) is the same; 2) if 'MD_RECOVERY_RUNNING' is not set, and 'MD_RECOVERY_NEEDED' is set, queue a work md_start_sync() directly; 3) md_start_sync() will try to choose a sync action, and then register sync_thread();
Because 'MD_RECOVERY_RUNNING' is cleared when sync_thread is done, 2) and 3) and md_do_sync() is always ran in serial and they can never concurrent, this change should not introduce any behavior change for now.
Also fix a problem that md_start_sync() can clear 'MD_RECOVERY_RUNNING' without protection in error path, which might affect the logical in md_check_recovery().
The advantage to change this is that array reconfiguration is independent from daemon now, and it'll be much easier to synchronize it with io, consider that io may rely on daemon thread to be done.
Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Xiao Ni xni@redhat.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20230825031622.1530464-4-yukuai1@huaweicloud.com Signed-off-by: Li Nan linan122@huawei.com --- drivers/md/md.c | 73 ++++++++++++++++++++++++++----------------------- 1 file changed, 39 insertions(+), 34 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c index 81633fb3d241..e9b41bf05855 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9297,6 +9297,22 @@ static bool md_choose_sync_action(struct mddev *mddev, int *spares) static void md_start_sync(struct work_struct *ws) { struct mddev *mddev = container_of(ws, struct mddev, sync_work); + int spares = 0; + + mddev_lock_nointr(mddev); + + if (!md_choose_sync_action(mddev, &spares)) + goto not_running; + + if (!mddev->pers->sync_request) + goto not_running; + + /* + * We are adding a device or devices to an array which has the bitmap + * stored on all devices. So make sure all bitmap pages get written. + */ + if (spares) + md_bitmap_write_all(mddev->bitmap);
rcu_assign_pointer(mddev->sync_thread, md_register_thread(md_do_sync, mddev, "resync")); @@ -9304,20 +9320,27 @@ static void md_start_sync(struct work_struct *ws) pr_warn("%s: could not start resync thread...\n", mdname(mddev)); /* leave the spares where they are, it shouldn't hurt */ - clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); - clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); - clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery); - clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); - clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery); - wake_up(&resync_wait); - if (test_and_clear_bit(MD_RECOVERY_RECOVER, - &mddev->recovery)) - if (mddev->sysfs_action) - sysfs_notify_dirent_safe(mddev->sysfs_action); - } else - md_wakeup_thread(mddev->sync_thread); + goto not_running; + } + + mddev_unlock(mddev); + md_wakeup_thread(mddev->sync_thread); sysfs_notify_dirent_safe(mddev->sysfs_action); md_new_event(); + return; + +not_running: + clear_bit(MD_RECOVERY_SYNC, &mddev->recovery); + clear_bit(MD_RECOVERY_RESHAPE, &mddev->recovery); + clear_bit(MD_RECOVERY_REQUESTED, &mddev->recovery); + clear_bit(MD_RECOVERY_CHECK, &mddev->recovery); + clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery); + mddev_unlock(mddev); + + wake_up(&resync_wait); + if (test_and_clear_bit(MD_RECOVERY_RECOVER, &mddev->recovery) && + mddev->sysfs_action) + sysfs_notify_dirent_safe(mddev->sysfs_action); }
/* @@ -9385,7 +9408,6 @@ void md_check_recovery(struct mddev *mddev) return;
if (mddev_trylock(mddev)) { - int spares = 0; bool try_set_sync = mddev->safemode != 0;
if (!mddev->external && mddev->safemode == 1) @@ -9472,31 +9494,14 @@ void md_check_recovery(struct mddev *mddev) clear_bit(MD_RECOVERY_INTR, &mddev->recovery); clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
- if (!test_and_clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery) || - test_bit(MD_RECOVERY_FROZEN, &mddev->recovery)) - goto not_running; - if (!md_choose_sync_action(mddev, &spares)) - goto not_running; - if (mddev->pers->sync_request) { - if (spares) { - /* We are adding a device or devices to an array - * which has the bitmap stored on all devices. - * So make sure all bitmap pages get written - */ - md_bitmap_write_all(mddev->bitmap); - } + if (test_and_clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery) && + !test_bit(MD_RECOVERY_FROZEN, &mddev->recovery)) { queue_work(md_misc_wq, &mddev->sync_work); - goto unlock; - } - not_running: - if (!mddev->sync_thread) { + } else { clear_bit(MD_RECOVERY_RUNNING, &mddev->recovery); wake_up(&resync_wait); - if (test_and_clear_bit(MD_RECOVERY_RECOVER, - &mddev->recovery)) - if (mddev->sysfs_action) - sysfs_notify_dirent_safe(mddev->sysfs_action); } + unlock: wake_up(&mddev->sb_wait); mddev_unlock(mddev);