From 23da422b1951cb8dbcb7c3090057cb6d5ceedf49 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 15 Dec 2014 12:57:01 +1100 Subject: [PATCH] md: use mddev->lock to protect updates to resync_{min,max}. There are interdependencies between these two sysfs attributes and whether a resync is currently running. Rather than depending on reconfig_mutex to ensure no races when testing these interdependencies are met, use the spinlock. This will allow the mutex to be remove from protecting this code in a subsequent patch. Signed-off-by: NeilBrown --- drivers/md/md.c | 58 ++++++++++++++++++++++++++++++++++++++++++++------------- drivers/md/md.h | 2 ++ 2 files changed, 47 insertions(+), 13 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 0f9bc9a..0f00c1e 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4269,22 +4269,36 @@ static ssize_t min_sync_store(struct mddev *mddev, const char *buf, size_t len) { unsigned long long min; + int err; + int chunk; + if (kstrtoull(buf, 10, &min)) return -EINVAL; + + spin_lock(&mddev->lock); + err = -EINVAL; if (min > mddev->resync_max) - return -EINVAL; + goto out_unlock; + + err = -EBUSY; if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) - return -EBUSY; + goto out_unlock; /* Must be a multiple of chunk_size */ - if (mddev->chunk_sectors) { + chunk = mddev->chunk_sectors; + if (chunk) { sector_t temp = min; - if (sector_div(temp, mddev->chunk_sectors)) - return -EINVAL; + + err = -EINVAL; + if (sector_div(temp, chunk)) + goto out_unlock; } mddev->resync_min = min; + err = 0; - return len; +out_unlock: + spin_unlock(&mddev->lock); + return err ?: len; } static struct md_sysfs_entry md_min_sync = @@ -4302,29 +4316,42 @@ max_sync_show(struct mddev *mddev, char *page) static ssize_t max_sync_store(struct mddev *mddev, const char *buf, size_t len) { + int err; + spin_lock(&mddev->lock); if (strncmp(buf, "max", 3) == 0) mddev->resync_max = MaxSector; else { unsigned long long max; + int chunk; + + err = -EINVAL; if (kstrtoull(buf, 10, &max)) - return -EINVAL; + goto out_unlock; if (max < mddev->resync_min) - return -EINVAL; + goto out_unlock; + + err = -EBUSY; if (max < mddev->resync_max && mddev->ro == 0 && test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) - return -EBUSY; + goto out_unlock; /* Must be a multiple of chunk_size */ - if (mddev->chunk_sectors) { + chunk = mddev->chunk_sectors; + if (chunk) { sector_t temp = max; - if (sector_div(temp, mddev->chunk_sectors)) - return -EINVAL; + + err = -EINVAL; + if (sector_div(temp, chunk)) + goto out_unlock; } mddev->resync_max = max; } wake_up(&mddev->recovery_wait); - return len; + err = 0; +out_unlock: + spin_unlock(&mddev->lock); + return err ?: len; } static struct md_sysfs_entry md_max_sync = @@ -7585,6 +7612,7 @@ void md_do_sync(struct md_thread *thread) skip: set_bit(MD_CHANGE_DEVS, &mddev->flags); + spin_lock(&mddev->lock); if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { /* We completed so min/max setting can be forgotten if used. */ if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) @@ -7593,6 +7621,8 @@ void md_do_sync(struct md_thread *thread) } else if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) mddev->resync_min = mddev->curr_resync_completed; mddev->curr_resync = 0; + spin_unlock(&mddev->lock); + wake_up(&resync_wait); set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); @@ -7793,7 +7823,9 @@ void md_check_recovery(struct mddev *mddev) * any transients in the value of "sync_action". */ mddev->curr_resync_completed = 0; + spin_lock(&mddev->lock); set_bit(MD_RECOVERY_RUNNING, &mddev->recovery); + spin_unlock(&mddev->lock); /* Clear some bits that don't mean anything, but * might be left set */ diff --git a/drivers/md/md.h b/drivers/md/md.h index b4fbd6a..6bf3faa 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -394,6 +394,8 @@ struct mddev { * pers (also protected by reconfig_mutex and pending IO). * clearing ->bitmap * clearing ->bitmap_info.file + * changing ->resync_{min,max} + * setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max}) */ spinlock_t lock; wait_queue_head_t sb_wait; /* for waiting on superblock updates */ -- 2.7.4