Revert "md: improve partition detection in md array"

This reverts commit 5b479c91da90eef605f851508744bfe8269591a0.

Quoth Neil Brown:

  "It causes an oops when auto-detecting raid arrays, and it doesn't
   seem easy to fix.

   The array may not be 'open' when do_md_run is called, so
   bdev->bd_disk might be NULL, so bd_set_size can oops.

   This whole approach of opening an md device before it has been
   assembled just seems to get more and more painful.  I think I'm going
   to have to come up with something clever to provide both backward
   comparability with usage expectation, and sane integration into the
   rest of the kernel."

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 18 insertions, 8 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2901d0c0ee9e..65814b0340cb 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3104,7 +3104,6 @@ static int do_md_run(mddev_t * mddev)
         struct gendisk *disk;
         struct mdk_personality *pers;
         char b[BDEVNAME_SIZE];
-        struct block_device *bdev;
 
         if (list_empty(&mddev->disks))
                 /* cannot run an array with no devices.. */
@@ -3332,13 +3331,7 @@ static int do_md_run(mddev_t * mddev)
         md_wakeup_thread(mddev->thread);
         md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */
 
-        bdev = bdget_disk(mddev->gendisk, 0);
-        if (bdev) {
-                bd_set_size(bdev, mddev->array_size << 1);
-                blkdev_ioctl(bdev->bd_inode, NULL, BLKRRPART, 0);
-                bdput(bdev);
-        }
-
+        mddev->changed = 1;
         md_new_event(mddev);
         kobject_uevent(&mddev->gendisk->kobj, KOBJ_CHANGE);
         return 0;
@@ -3460,6 +3453,7 @@ static int do_md_stop(mddev_t * mddev, int mode)
                         mddev->pers = NULL;
 
                         set_capacity(disk, 0);
+                        mddev->changed = 1;
 
                         if (mddev->ro)
                                 mddev->ro = 0;
@@ -4599,6 +4593,20 @@ static int md_release(struct inode *inode, struct file * file)
         return 0;
 }
 
+static int md_media_changed(struct gendisk *disk)
+{
+        mddev_t *mddev = disk->private_data;
+
+        return mddev->changed;
+}
+
+static int md_revalidate(struct gendisk *disk)
+{
+        mddev_t *mddev = disk->private_data;
+
+        mddev->changed = 0;
+        return 0;
+}
 static struct block_device_operations md_fops =
 {
         .owner          = THIS_MODULE,
@@ -4606,6 +4614,8 @@ static struct block_device_operations md_fops =
         .release        = md_release,
         .ioctl          = md_ioctl,
         .getgeo         = md_getgeo,
+        .media_changed  = md_media_changed,
+        .revalidate_disk= md_revalidate,
 };
 
 static int md_thread(void * arg)