Revert "loop: cleanup partitions when detaching loop device"

This reverts commit 8761a3dc1f07b163414e2215a2cadbb4cfe2a107.

There are situations where the destruction path is called
with the bdev->bd_mutex already held, which then deadlocks in
loop_clr_fd(). The normal partition cleanup does a trylock()
on the mutex, but it'd be nice to have a more bullet proof
method in loop. So punt this more involved fix to the next
merge window, and just back out this buggy fix for now.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

2 files changed, 2 insertions, 20 deletions

diff --git a/block/partition-generic.c b/block/partition-generic.c
index ae95ee6a58aa..789cdea05893 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -257,7 +257,6 @@ void delete_partition(struct gendisk *disk, int partno)
 
         hd_struct_put(part);
 }
-EXPORT_SYMBOL(delete_partition);
 
 static ssize_t whole_disk_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index fe5f6403417f..ee13a82f3f5e 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1044,29 +1044,12 @@ 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);
-
-        /*
-         * Remove all partitions, since BLKRRPART won't remove user
-         * added partitions when max_part=0
-         */
-        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