> I have not tested it yet, but I am pretty sure it won't work. It > looks like the patch changes the BLKRRPART path to go ahead and remove > existing partitions when GENHD_FL_NO_PARTSCAN is set. loop doesn't > issue the BLKRRPART ioctl when !LO_FLAGS_PARTSCAN so this won't help. > I think loop needs to set GENHD_FL_NO_PARTSCAN and then issue the > ioctl regardless of the LO_FLAGS_PARTSCAN flag to get the partitions > to be removed. I will try to test tonight.
After testing, my initial thoughts appeared to have been correct. I had to modify the patch as follows. To test, simply do: truncate -s 10m img losetup /dev/loop0 img parted /dev/loop0 mklabel msdos mkpart primary ext2 1m 2m quit ls /dev/loop0* Note the /dev/loop0p1 node. Run losetup -d /dev/loop0 and see if it is still there.
diff --git a/block/ioctl.c b/block/ioctl.c
index a31d91d..8b78b5a 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -155,7 +155,7 @@ static int blkdev_reread_part(struct block_device *bdev)
struct gendisk *disk = bdev->bd_disk;
int res;
- if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
+ if (bdev != bdev->bd_contains)
return -EINVAL;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
diff --git a/block/partition-generic.c b/block/partition-generic.c
index 1cb4dec..0e7d637 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -430,6 +430,15 @@ rescan:
disk->fops->revalidate_disk(disk);
check_disk_size_change(disk, bdev);
bdev->bd_invalidated = 0;
+
+ /*
+ * If partition scanning is disabled, we are done.
+ */
+ if (!disk_part_scan_enabled(disk)) {
+ kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+ return 0;
+ }
+
if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
return 0;
if (IS_ERR(state)) {
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 8bc6d39..326fac9 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1039,11 +1039,9 @@ 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_disk->flags |= GENHD_FL_NO_PART_SCAN;
+ 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);
/*
* Need not hold lo_ctl_mutex to fput backing file.
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