On Fri, Apr 23, 2021 at 02:54:36PM -0700, Linus Torvalds wrote:
> On Fri, Apr 23, 2021 at 2:06 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
> >
> > A single fix for a behavioral regression in this series, when re-reading
> > the partition table with partitions open.
>
> Hmm. The fact that it's no longer calling blk_drop_partitions() didn't
> just mean that the check for "bdev->bd_part_count" was lost (now
> re-instated).
It still calls blk_drop_partitions:
blkdev_reread_part
-> blkdev_get_by_dev
-> __blkdev_get
-> bdev_disk_changed
-> blk_drop_partitions
The difference is that before blkdev_reread_part called
bdev_disk_changed directly. We now do it through blkdev_get to hook
into the driver. But __blkdev_get ignores the return value from
bdev_disk_changed.
> It also seems to mean that blkdev_reread_part() no longer does the
>
> sync_blockdev(bdev);
> invalidate_bdev(bdev);
>
> to write back and invalidate any caches.
>
> Are we sure cache writeback/invalidate isn't needed? Or does it get
> done some other place?
It is still in place. But given how our cache coherency works not
actually needed anyway, but peeling that onion will take a while.
