md: protect ->pers changes with mddev->lock
->pers is already protected by ->reconfig_mutex, and cannot possibly change when there are threads running or outstanding IO. However there are some places where we access ->pers not in a thread or IO context, and where ->reconfig_mutex is unnecessarily heavy-weight: level_show and md_seq_show(). So protect all changes, and those accesses, with ->lock. This is a step toward taking those accesses out from under reconfig_mutex. [Fixed missing "mddev->pers" -> "pers" conversion, thanks to Dan Carpenter <dan.carpenter@oracle.com>] Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown
parent
db721d32b7
commit
36d091f475
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@ -3264,15 +3264,20 @@ __ATTR(safe_mode_delay, S_IRUGO|S_IWUSR,safe_delay_show, safe_delay_store);
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static ssize_t
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level_show(struct mddev *mddev, char *page)
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{
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struct md_personality *p = mddev->pers;
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struct md_personality *p;
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int ret;
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spin_lock(&mddev->lock);
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p = mddev->pers;
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if (p)
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return sprintf(page, "%s\n", p->name);
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ret = sprintf(page, "%s\n", p->name);
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else if (mddev->clevel[0])
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return sprintf(page, "%s\n", mddev->clevel);
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ret = sprintf(page, "%s\n", mddev->clevel);
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else if (mddev->level != LEVEL_NONE)
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return sprintf(page, "%d\n", mddev->level);
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ret = sprintf(page, "%d\n", mddev->level);
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else
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return 0;
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ret = 0;
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spin_unlock(&mddev->lock);
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return ret;
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}
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static ssize_t
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@ -3374,6 +3379,8 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
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/* Looks like we have a winner */
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mddev_suspend(mddev);
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mddev_detach(mddev);
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spin_lock(&mddev->lock);
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oldpers = mddev->pers;
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oldpriv = mddev->private;
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mddev->pers = pers;
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@ -3385,6 +3392,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len)
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mddev->delta_disks = 0;
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mddev->reshape_backwards = 0;
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mddev->degraded = 0;
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spin_unlock(&mddev->lock);
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if (oldpers->sync_request == NULL &&
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mddev->external) {
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@ -4866,7 +4874,6 @@ int md_run(struct mddev *mddev)
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mddev->clevel);
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return -EINVAL;
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}
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mddev->pers = pers;
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spin_unlock(&pers_lock);
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if (mddev->level != pers->level) {
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mddev->level = pers->level;
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@ -4877,7 +4884,6 @@ int md_run(struct mddev *mddev)
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if (mddev->reshape_position != MaxSector &&
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pers->start_reshape == NULL) {
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/* This personality cannot handle reshaping... */
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mddev->pers = NULL;
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module_put(pers->owner);
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return -EINVAL;
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}
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@ -4921,19 +4927,19 @@ int md_run(struct mddev *mddev)
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if (start_readonly && mddev->ro == 0)
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mddev->ro = 2; /* read-only, but switch on first write */
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err = mddev->pers->run(mddev);
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err = pers->run(mddev);
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if (err)
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printk(KERN_ERR "md: pers->run() failed ...\n");
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else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
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else if (pers->size(mddev, 0, 0) < mddev->array_sectors) {
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WARN_ONCE(!mddev->external_size, "%s: default size too small,"
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" but 'external_size' not in effect?\n", __func__);
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printk(KERN_ERR
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"md: invalid array_size %llu > default size %llu\n",
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(unsigned long long)mddev->array_sectors / 2,
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(unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
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(unsigned long long)pers->size(mddev, 0, 0) / 2);
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err = -EINVAL;
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}
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if (err == 0 && mddev->pers->sync_request &&
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if (err == 0 && pers->sync_request &&
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(mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
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err = bitmap_create(mddev);
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if (err)
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@ -4942,9 +4948,8 @@ int md_run(struct mddev *mddev)
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}
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if (err) {
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mddev_detach(mddev);
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mddev->pers->free(mddev, mddev->private);
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module_put(mddev->pers->owner);
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mddev->pers = NULL;
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pers->free(mddev, mddev->private);
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module_put(pers->owner);
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bitmap_destroy(mddev);
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return err;
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}
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@ -4953,7 +4958,7 @@ int md_run(struct mddev *mddev)
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mddev->queue->backing_dev_info.congested_fn = md_congested;
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blk_queue_merge_bvec(mddev->queue, md_mergeable_bvec);
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}
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if (mddev->pers->sync_request) {
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if (pers->sync_request) {
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if (mddev->kobj.sd &&
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sysfs_create_group(&mddev->kobj, &md_redundancy_group))
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printk(KERN_WARNING
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@ -4972,7 +4977,10 @@ int md_run(struct mddev *mddev)
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mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
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mddev->in_sync = 1;
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smp_wmb();
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spin_lock(&mddev->lock);
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mddev->pers = pers;
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mddev->ready = 1;
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spin_unlock(&mddev->lock);
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rdev_for_each(rdev, mddev)
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if (rdev->raid_disk >= 0)
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if (sysfs_link_rdev(mddev, rdev))
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@ -5126,7 +5134,7 @@ static void mddev_detach(struct mddev *mddev)
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wait_event(bitmap->behind_wait,
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atomic_read(&bitmap->behind_writes) == 0);
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}
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if (mddev->pers->quiesce) {
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if (mddev->pers && mddev->pers->quiesce) {
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mddev->pers->quiesce(mddev, 1);
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mddev->pers->quiesce(mddev, 0);
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}
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@ -5137,13 +5145,16 @@ static void mddev_detach(struct mddev *mddev)
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static void __md_stop(struct mddev *mddev)
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{
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mddev->ready = 0;
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struct md_personality *pers = mddev->pers;
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mddev_detach(mddev);
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mddev->pers->free(mddev, mddev->private);
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if (mddev->pers->sync_request && mddev->to_remove == NULL)
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mddev->to_remove = &md_redundancy_group;
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module_put(mddev->pers->owner);
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spin_lock(&mddev->lock);
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mddev->ready = 0;
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mddev->pers = NULL;
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spin_unlock(&mddev->lock);
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pers->free(mddev, mddev->private);
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if (pers->sync_request && mddev->to_remove == NULL)
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mddev->to_remove = &md_redundancy_group;
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module_put(pers->owner);
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clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
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}
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@ -6942,6 +6953,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
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if (mddev_lock(mddev) < 0)
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return -EINTR;
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spin_lock(&mddev->lock);
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if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) {
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seq_printf(seq, "%s : %sactive", mdname(mddev),
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mddev->pers ? "" : "in");
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@ -7012,6 +7024,7 @@ static int md_seq_show(struct seq_file *seq, void *v)
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seq_printf(seq, "\n");
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}
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spin_unlock(&mddev->lock);
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mddev_unlock(mddev);
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return 0;
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@ -391,6 +391,7 @@ struct mddev {
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* rdev superblocks, events
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* clearing MD_CHANGE_*
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* in_sync - and related safemode and MD_CHANGE changes
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* pers (also protected by reconfig_mutex and pending IO).
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*/
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spinlock_t lock;
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wait_queue_head_t sb_wait; /* for waiting on superblock updates */
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