diff options
author | Yu Kuai <yukuai3@huawei.com> | 2023-10-10 18:19:43 +0300 |
---|---|---|
committer | Song Liu <song@kernel.org> | 2023-10-11 04:49:49 +0300 |
commit | 714d20150ed85811193ae07a494d91f9927c590f (patch) | |
tree | 0e14a78c85da36565bd3ade9eb4cd3e3952799c4 /drivers/md/md.c | |
parent | 2e82248b70f48a98f3720cdaa8ea7a4e7f8bd760 (diff) | |
download | linux-714d20150ed85811193ae07a494d91f9927c590f.tar.xz |
md: add new helpers to suspend/resume array
Advantages for new apis:
- reconfig_mutex is not required;
- the weird logical that suspend array hold 'reconfig_mutex' for
mddev_check_recovery() to update superblock is not needed;
- the specail handling, 'pers->prepare_suspend', for raid456 is not
needed;
- It's safe to be called at any time once mddev is allocated, and it's
designed to be used from slow path where array configuration is changed;
- the new helpers is designed to be called before mddev_lock(), hence
it support to be interrupted by user as well.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20231010151958.145896-5-yukuai1@huaweicloud.com
Diffstat (limited to 'drivers/md/md.c')
-rw-r--r-- | drivers/md/md.c | 102 |
1 files changed, 100 insertions, 2 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index cf929c42cdbe..201de29d913c 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -443,12 +443,22 @@ void mddev_suspend(struct mddev *mddev) lockdep_is_held(&mddev->reconfig_mutex)); WARN_ON_ONCE(thread && current == thread->tsk); - if (mddev->suspended++) + + /* can't concurrent with __mddev_suspend() and __mddev_resume() */ + mutex_lock(&mddev->suspend_mutex); + if (mddev->suspended++) { + mutex_unlock(&mddev->suspend_mutex); return; + } + wake_up(&mddev->sb_wait); set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags); percpu_ref_kill(&mddev->active_io); + /* + * TODO: cleanup 'pers->prepare_suspend after all callers are replaced + * by __mddev_suspend(). + */ if (mddev->pers && mddev->pers->prepare_suspend) mddev->pers->prepare_suspend(mddev); @@ -459,14 +469,21 @@ void mddev_suspend(struct mddev *mddev) del_timer_sync(&mddev->safemode_timer); /* restrict memory reclaim I/O during raid array is suspend */ mddev->noio_flag = memalloc_noio_save(); + + mutex_unlock(&mddev->suspend_mutex); } EXPORT_SYMBOL_GPL(mddev_suspend); void mddev_resume(struct mddev *mddev) { lockdep_assert_held(&mddev->reconfig_mutex); - if (--mddev->suspended) + + /* can't concurrent with __mddev_suspend() and __mddev_resume() */ + mutex_lock(&mddev->suspend_mutex); + if (--mddev->suspended) { + mutex_unlock(&mddev->suspend_mutex); return; + } /* entred the memalloc scope from mddev_suspend() */ memalloc_noio_restore(mddev->noio_flag); @@ -477,9 +494,89 @@ void mddev_resume(struct mddev *mddev) set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ + + mutex_unlock(&mddev->suspend_mutex); } EXPORT_SYMBOL_GPL(mddev_resume); +int __mddev_suspend(struct mddev *mddev, bool interruptible) +{ + int err = 0; + + /* + * hold reconfig_mutex to wait for normal io will deadlock, because + * other context can't update super_block, and normal io can rely on + * updating super_block. + */ + lockdep_assert_not_held(&mddev->reconfig_mutex); + + if (interruptible) + err = mutex_lock_interruptible(&mddev->suspend_mutex); + else + mutex_lock(&mddev->suspend_mutex); + if (err) + return err; + + if (mddev->suspended) { + WRITE_ONCE(mddev->suspended, mddev->suspended + 1); + mutex_unlock(&mddev->suspend_mutex); + return 0; + } + + percpu_ref_kill(&mddev->active_io); + if (interruptible) + err = wait_event_interruptible(mddev->sb_wait, + percpu_ref_is_zero(&mddev->active_io)); + else + wait_event(mddev->sb_wait, + percpu_ref_is_zero(&mddev->active_io)); + if (err) { + percpu_ref_resurrect(&mddev->active_io); + mutex_unlock(&mddev->suspend_mutex); + return err; + } + + /* + * For raid456, io might be waiting for reshape to make progress, + * allow new reshape to start while waiting for io to be done to + * prevent deadlock. + */ + WRITE_ONCE(mddev->suspended, mddev->suspended + 1); + + del_timer_sync(&mddev->safemode_timer); + /* restrict memory reclaim I/O during raid array is suspend */ + mddev->noio_flag = memalloc_noio_save(); + + mutex_unlock(&mddev->suspend_mutex); + return 0; +} +EXPORT_SYMBOL_GPL(__mddev_suspend); + +void __mddev_resume(struct mddev *mddev) +{ + lockdep_assert_not_held(&mddev->reconfig_mutex); + + mutex_lock(&mddev->suspend_mutex); + WRITE_ONCE(mddev->suspended, mddev->suspended - 1); + if (mddev->suspended) { + mutex_unlock(&mddev->suspend_mutex); + return; + } + + /* entred the memalloc scope from __mddev_suspend() */ + memalloc_noio_restore(mddev->noio_flag); + + percpu_ref_resurrect(&mddev->active_io); + wake_up(&mddev->sb_wait); + + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + md_wakeup_thread(mddev->thread); + md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ + + mutex_unlock(&mddev->suspend_mutex); +} +EXPORT_SYMBOL_GPL(__mddev_resume); + /* * Generic flush handling for md */ @@ -672,6 +769,7 @@ int mddev_init(struct mddev *mddev) mutex_init(&mddev->open_mutex); mutex_init(&mddev->reconfig_mutex); mutex_init(&mddev->sync_mutex); + mutex_init(&mddev->suspend_mutex); mutex_init(&mddev->bitmap_info.mutex); INIT_LIST_HEAD(&mddev->disks); INIT_LIST_HEAD(&mddev->all_mddevs); |