On Fri 28-01-22 14:00:17, Christoph Hellwig wrote:
> Nothing prevents a file system or userspace opener of the block device
> from redirtying the page right afte sync_blockdev returned. Fortunately
> data in the page cache during a block device change is mostly harmless
> anyway.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Tested-by: Darrick J. Wong <djwong@xxxxxxxxxx>
OK. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> drivers/block/loop.c | 20 --------------------
> 1 file changed, 20 deletions(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 6ec55a5d9dfc4..d3a7f281ce1b6 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1278,15 +1278,6 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
> /* I/O need to be drained during transfer transition */
> blk_mq_freeze_queue(lo->lo_queue);
>
> - if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
> - /* If any pages were dirtied after invalidate_bdev(), try again */
> - err = -EAGAIN;
> - pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
> - __func__, lo->lo_number, lo->lo_file_name,
> - lo->lo_device->bd_inode->i_mapping->nrpages);
> - goto out_unfreeze;
> - }
> -
> prev_lo_flags = lo->lo_flags;
>
> err = loop_set_status_from_info(lo, info);
> @@ -1497,21 +1488,10 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
> invalidate_bdev(lo->lo_device);
>
> blk_mq_freeze_queue(lo->lo_queue);
> -
> - /* invalidate_bdev should have truncated all the pages */
> - if (lo->lo_device->bd_inode->i_mapping->nrpages) {
> - err = -EAGAIN;
> - pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
> - __func__, lo->lo_number, lo->lo_file_name,
> - lo->lo_device->bd_inode->i_mapping->nrpages);
> - goto out_unfreeze;
> - }
> -
> blk_queue_logical_block_size(lo->lo_queue, arg);
> blk_queue_physical_block_size(lo->lo_queue, arg);
> blk_queue_io_min(lo->lo_queue, arg);
> loop_update_dio(lo);
> -out_unfreeze:
> blk_mq_unfreeze_queue(lo->lo_queue);
>
> return err;
> --
> 2.30.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
