loop: cleanup partitions when detaching loop device

Any partitions added by user space to the loop device were being left in
place after detaching the loop device.  This was because the detach path
issued a BLKRRPART to clean up partitions if LO_FLAGS_PARTSCAN was set,
meaning that the partitions were auto scanned on attach.  Replace this
BLKRRPART with code that unconditionally cleans up partitions on detach
instead.

The user-visible effect of this bug is that the partition devnodes still
show up after detaching the backing file, and I think the partitions
remained in place after attaching a new file even though it had different
or no partitions at all.

Signed-off-by: Phillip Susi <psusi@ubuntu.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 747bb2af69dcc55fec530466a9f55d06914ba8f7..738cb0c6f9c3d2bef2b6953b5333ee62100e3d75 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1044,12 +1044,24 @@ static int loop_clr_fd(struct loop_device *lo)
        lo->lo_state = Lo_unbound;
        /* This is safe: open() is still holding a reference. */
        module_put(THIS_MODULE);
-       if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
-               ioctl_by_bdev(bdev, BLKRRPART, 0);
        lo->lo_flags = 0;
        if (!part_shift)
                lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
        mutex_unlock(&lo->lo_ctl_mutex);
+       if (bdev)
+       {
+               struct disk_part_iter piter;
+               struct hd_struct *part;
+
+               mutex_lock_nested(&bdev->bd_mutex, 1);
+               invalidate_partition(bdev->bd_disk, 0);
+               disk_part_iter_init(&piter, bdev->bd_disk, DISK_PITER_INCL_EMPTY);
+               while ((part = disk_part_iter_next(&piter)))
+                       delete_partition(bdev->bd_disk, part->partno);
+               disk_part_iter_exit(&piter);
+               mutex_unlock(&bdev->bd_mutex);
+       }
+
        /*
         * Need not hold lo_ctl_mutex to fput backing file.
         * Calling fput holding lo_ctl_mutex triggers a circular