md: Better control of when do_md_stop is allowed to stop the array.

do_md_stop check the number of active users before allowing the array
to be stopped.
Two problems:
  1/ it assumes the request is coming through an open file descriptor
     (via ioctl) so it allows for that.  This is not always the case.
  2/ it doesn't do the check it the array hasn't been activated.
     This is not good for cases when we use an inactive array to hold
     some devices in a container.

Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 15 insertions, 14 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 328e247e2bf5..4c4c79da72b9 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2688,7 +2688,7 @@ array_state_show(mddev_t *mddev, char *page)
         return sprintf(page, "%s\n", array_states[st]);
 }
 
-static int do_md_stop(mddev_t * mddev, int ro);
+static int do_md_stop(mddev_t * mddev, int ro, int is_open);
 static int do_md_run(mddev_t * mddev);
 static int restart_array(mddev_t *mddev);
 
@@ -2704,14 +2704,14 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
                 /* stopping an active array */
                 if (atomic_read(&mddev->active) > 1)
                         return -EBUSY;
-                err = do_md_stop(mddev, 0);
+                err = do_md_stop(mddev, 0, 0);
                 break;
         case inactive:
                 /* stopping an active array */
                 if (mddev->pers) {
                         if (atomic_read(&mddev->active) > 1)
                                 return -EBUSY;
-                        err = do_md_stop(mddev, 2);
+                        err = do_md_stop(mddev, 2, 0);
                 } else
                         err = 0; /* already inactive */
                 break;
@@ -2719,7 +2719,7 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
                 break; /* not supported yet */
         case readonly:
                 if (mddev->pers)
-                        err = do_md_stop(mddev, 1);
+                        err = do_md_stop(mddev, 1, 0);
                 else {
                         mddev->ro = 1;
                         set_disk_ro(mddev->gendisk, 1);
@@ -2729,7 +2729,7 @@ array_state_store(mddev_t *mddev, const char *buf, size_t len)
         case read_auto:
                 if (mddev->pers) {
                         if (mddev->ro != 1)
-                                err = do_md_stop(mddev, 1);
+                                err = do_md_stop(mddev, 1, 0);
                         else
                                 err = restart_array(mddev);
                         if (err == 0) {
@@ -3818,16 +3818,17 @@ static void restore_bitmap_write_access(struct file *file)
  *   1 - switch to readonly
  *   2 - stop but do not disassemble array
  */
-static int do_md_stop(mddev_t * mddev, int mode)
+static int do_md_stop(mddev_t * mddev, int mode, int is_open)
 {
         int err = 0;
         struct gendisk *disk = mddev->gendisk;
 
+        if (atomic_read(&mddev->active) > 1 + is_open) {
+                printk("md: %s still in use.\n",mdname(mddev));
+                return -EBUSY;
+        }
+
         if (mddev->pers) {
-                if (atomic_read(&mddev->active)>2) {
-                        printk("md: %s still in use.\n",mdname(mddev));
-                        return -EBUSY;
-                }
 
                 if (mddev->sync_thread) {
                         set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
@@ -3976,7 +3977,7 @@ static void autorun_array(mddev_t *mddev)
         err = do_md_run (mddev);
         if (err) {
                 printk(KERN_WARNING "md: do_md_run() returned %d\n", err);
-                do_md_stop (mddev, 0);
+                do_md_stop (mddev, 0, 0);
         }
 }
 
@@ -4931,11 +4932,11 @@ static int md_ioctl(struct inode *inode, struct file *file,
                         goto done_unlock;
 
                 case STOP_ARRAY:
-                        err = do_md_stop (mddev, 0);
+                        err = do_md_stop (mddev, 0, 1);
                         goto done_unlock;
 
                 case STOP_ARRAY_RO:
-                        err = do_md_stop (mddev, 1);
+                        err = do_md_stop (mddev, 1, 1);
                         goto done_unlock;
 
         }
@@ -6226,7 +6227,7 @@ static int md_notify_reboot(struct notifier_block *this,
 
                 for_each_mddev(mddev, tmp)
                         if (mddev_trylock(mddev)) {
-                                do_md_stop (mddev, 1);
+                                do_md_stop (mddev, 1, 0);
                                 mddev_unlock(mddev);
                         }
                 /*