Commit b0bd158d authored by Martijn Coenen's avatar Martijn Coenen Committed by Jens Axboe
Browse files

loop: Refactor loop_set_status() size calculation 



figure_loop_size() calculates the loop size based on the passed in
parameters, but at the same time it updates the offset and sizelimit
parameters in the loop device configuration. That is a somewhat
unexpected side effect of a function with this name, and it is only only
needed by one of the two callers of this function - loop_set_status().

Move the lo_offset and lo_sizelimit assignment back into loop_set_status(),
and use the newly factored out functions to validate and apply the newly
calculated size. This allows us to get rid of figure_loop_size() in a
follow-up commit.

Signed-off-by: default avatarMartijn Coenen <maco@android.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 716ad098

drivers/block/loop.c

+19 −18
Original line number Diff line number Diff line
@@ -250,11 +250,6 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) 
{

	loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);



	if (lo->lo_offset != offset)

		lo->lo_offset = offset;

	if (lo->lo_sizelimit != sizelimit)

		lo->lo_sizelimit = sizelimit;



	loop_set_size(lo, size);

}
@@ -1272,6 +1267,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 
	kuid_t uid = current_uid();

	struct block_device *bdev;

	bool partscan = false;

	bool size_changed = false;



	err = mutex_lock_killable(&loop_ctl_mutex);

	if (err)
@@ -1293,6 +1289,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 


	if (lo->lo_offset != info->lo_offset ||

	    lo->lo_sizelimit != info->lo_sizelimit) {

		size_changed = true;

		sync_blockdev(lo->lo_device);

		kill_bdev(lo->lo_device);

	}
@@ -1300,6 +1297,15 @@ 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 kill_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;

	}



	err = loop_release_xfer(lo);

	if (err)

		goto out_unfreeze;
@@ -1323,19 +1329,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 
	if (err)

		goto out_unfreeze;



	if (lo->lo_offset != info->lo_offset ||

	    lo->lo_sizelimit != info->lo_sizelimit) {

		/* kill_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;

		}

		figure_loop_size(lo, info->lo_offset, info->lo_sizelimit);

	}



	lo->lo_offset = info->lo_offset;

	lo->lo_sizelimit = info->lo_sizelimit;

	memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);

	memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);

	lo->lo_file_name[LO_NAME_SIZE-1] = 0;
@@ -1359,6 +1354,12 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 
		lo->lo_key_owner = uid;

	}



	if (size_changed) {

		loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,

					   lo->lo_backing_file);

		loop_set_size(lo, new_size);

	}



	loop_config_discard(lo);



	/* update dio if lo_offset or transfer is changed */

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