md: manage redundancy group in sysfs when changing level.
Some levels expect the 'redundancy group' to be present,
others don't.
So when we change level of an array we might need to
add or remove this group.
This requires fixing up the current practice of overloading ->private
to indicate (when ->pers == NULL) that something needs to be removed.
So create a new ->to_remove to fill that role.
When changing levels, we may need to add or remove attributes. When
changing RAID5 -> RAID6, we both add and remove the same thing. It is
important to catch this and optimise it out as the removal is delayed
until a lock is released, so trying to add immediately would cause
problems.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index edf777f6..e8d2388 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -509,9 +509,9 @@
static struct attribute_group md_redundancy_group;
-static inline void mddev_unlock(mddev_t * mddev)
+static void mddev_unlock(mddev_t * mddev)
{
- if (mddev->pers == NULL && mddev->private) {
+ if (mddev->to_remove) {
/* These cannot be removed under reconfig_mutex as
* an access to the files will try to take reconfig_mutex
* while holding the file unremovable, which leads to
@@ -520,16 +520,20 @@
* it while holding reconfig_mutex, and md_run can
* use it to wait for the remove to complete.
*/
+ struct attribute_group *to_remove = mddev->to_remove;
+ mddev->to_remove = NULL;
mutex_lock(&mddev->open_mutex);
mutex_unlock(&mddev->reconfig_mutex);
- sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
- if (mddev->private != (void*)1)
- sysfs_remove_group(&mddev->kobj, mddev->private);
- if (mddev->sysfs_action)
- sysfs_put(mddev->sysfs_action);
- mddev->sysfs_action = NULL;
- mddev->private = NULL;
+ if (to_remove != &md_redundancy_group)
+ sysfs_remove_group(&mddev->kobj, to_remove);
+ if (mddev->pers == NULL ||
+ mddev->pers->sync_request == NULL) {
+ sysfs_remove_group(&mddev->kobj, &md_redundancy_group);
+ if (mddev->sysfs_action)
+ sysfs_put(mddev->sysfs_action);
+ mddev->sysfs_action = NULL;
+ }
mutex_unlock(&mddev->open_mutex);
} else
mutex_unlock(&mddev->reconfig_mutex);
@@ -2996,6 +3000,23 @@
/* Looks like we have a winner */
mddev_suspend(mddev);
mddev->pers->stop(mddev);
+
+ if (mddev->pers->sync_request == NULL &&
+ pers->sync_request != NULL) {
+ /* need to add the md_redundancy_group */
+ if (sysfs_create_group(&mddev->kobj, &md_redundancy_group))
+ printk(KERN_WARNING
+ "md: cannot register extra attributes for %s\n",
+ mdname(mddev));
+ mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, "sync_action");
+ }
+ if (mddev->pers->sync_request != NULL &&
+ pers->sync_request == NULL) {
+ /* need to remove the md_redundancy_group */
+ if (mddev->to_remove == NULL)
+ mddev->to_remove = &md_redundancy_group;
+ }
+
module_put(mddev->pers->owner);
/* Invalidate devices that are now superfluous */
list_for_each_entry(rdev, &mddev->disks, same_set)
@@ -4550,8 +4571,8 @@
mddev->queue->unplug_fn = NULL;
mddev->queue->backing_dev_info.congested_fn = NULL;
module_put(mddev->pers->owner);
- if (mddev->pers->sync_request && mddev->private == NULL)
- mddev->private = (void*)1;
+ if (mddev->pers->sync_request && mddev->to_remove == NULL)
+ mddev->to_remove = &md_redundancy_group;
mddev->pers = NULL;
/* tell userspace to handle 'inactive' */
sysfs_notify_dirent(mddev->sysfs_state);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 8e4c75c..722f5df 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -305,6 +305,7 @@
atomic_t max_corr_read_errors; /* max read retries */
struct list_head all_mddevs;
+ struct attribute_group *to_remove;
/* Generic barrier handling.
* If there is a pending barrier request, all other
* writes are blocked while the devices are flushed.
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 70ffbd0..a361398 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5090,7 +5090,9 @@
}
/* Ok, everything is just fine now */
- if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
+ if (mddev->to_remove == &raid5_attrs_group)
+ mddev->to_remove = NULL;
+ else if (sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
printk(KERN_WARNING
"raid5: failed to create sysfs attributes for %s\n",
mdname(mddev));
@@ -5137,7 +5139,8 @@
mddev->queue->backing_dev_info.congested_fn = NULL;
blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
free_conf(conf);
- mddev->private = &raid5_attrs_group;
+ mddev->private = NULL;
+ mddev->to_remove = &raid5_attrs_group;
return 0;
}