Commit c2fccc1c authored by Jens Axboe's avatar Jens Axboe
Browse files

Revert "loop: cleanup partitions when detaching loop device" 



This reverts commit 8761a3dc.

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: default avatarJens Axboe <axboe@kernel.dk>
parent c66bb3f0

block/partition-generic.c

+0 −1
Original line number Diff line number Diff line
@@ -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)

drivers/block/loop.c

+2 −19
Original line number Diff line number Diff line
@@ -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

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