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-rw-r--r--drivers/md/md.c41
1 files changed, 31 insertions, 10 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2ecd1d5eb4f..e1678a0f91e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -507,9 +507,32 @@ static inline int mddev_trylock(mddev_t * mddev)
return mutex_trylock(&mddev->reconfig_mutex);
}
+static struct attribute_group md_redundancy_group;
+
static inline void mddev_unlock(mddev_t * mddev)
{
- mutex_unlock(&mddev->reconfig_mutex);
+ if (mddev->pers == NULL && mddev->private) {
+ /* 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
+ * a deadlock.
+ * So hold open_mutex instead - we are allowed to take
+ * it while holding reconfig_mutex, and md_run can
+ * use it to wait for the remove to complete.
+ */
+ 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;
+ mutex_unlock(&mddev->open_mutex);
+ } else
+ mutex_unlock(&mddev->reconfig_mutex);
md_wakeup_thread(mddev->thread);
}
@@ -4081,15 +4104,6 @@ static void mddev_delayed_delete(struct work_struct *ws)
{
mddev_t *mddev = container_of(ws, mddev_t, del_work);
- if (mddev->private) {
- 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;
- }
sysfs_remove_group(&mddev->kobj, &md_bitmap_group);
kobject_del(&mddev->kobj);
kobject_put(&mddev->kobj);
@@ -4247,6 +4261,13 @@ static int do_md_run(mddev_t * mddev)
if (mddev->pers)
return -EBUSY;
+ /* These two calls synchronise us with the
+ * sysfs_remove_group calls in mddev_unlock,
+ * so they must have completed.
+ */
+ mutex_lock(&mddev->open_mutex);
+ mutex_unlock(&mddev->open_mutex);
+
/*
* Analyze all RAID superblock(s)
*/