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Commit f2c6df7d authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Jens Axboe
Browse files

loop: support 4k physical blocksize 



When generating bootable VM images certain systems (most notably
s390x) require devices with 4k blocksize. This patch implements
a new flag 'LO_FLAGS_BLOCKSIZE' which will set the physical
blocksize to that of the underlying device, and allow to change
the logical blocksize for up to the physical blocksize.

Signed-off-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 51001b7d

drivers/block/loop.c

+37 −6
Original line number Diff line number Diff line
@@ -221,7 +221,8 @@ static void __loop_update_dio(struct loop_device *lo, bool dio) 
}



static int

figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)

figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit,

		 loff_t logical_blocksize)

{

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

	sector_t x = (sector_t)size;
@@ -233,6 +234,12 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) 
		lo->lo_offset = offset;

	if (lo->lo_sizelimit != sizelimit)

		lo->lo_sizelimit = sizelimit;

	if (lo->lo_flags & LO_FLAGS_BLOCKSIZE) {

		lo->lo_logical_blocksize = logical_blocksize;

		blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);

		blk_queue_logical_block_size(lo->lo_queue,

					     lo->lo_logical_blocksize);

	}

	set_capacity(lo->lo_disk, x);

	bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);

	/* let user-space know about the new size */
@@ -810,6 +817,7 @@ static void loop_config_discard(struct loop_device *lo) 
	struct file *file = lo->lo_backing_file;

	struct inode *inode = file->f_mapping->host;

	struct request_queue *q = lo->lo_queue;

	int lo_bits = 9;



	/*

	 * We use punch hole to reclaim the free space used by the
@@ -829,8 +837,11 @@ static void loop_config_discard(struct loop_device *lo) 


	q->limits.discard_granularity = inode->i_sb->s_blocksize;

	q->limits.discard_alignment = 0;

	blk_queue_max_discard_sectors(q, UINT_MAX >> 9);

	blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> 9);

	if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)

		lo_bits = blksize_bits(lo->lo_logical_blocksize);



	blk_queue_max_discard_sectors(q, UINT_MAX >> lo_bits);

	blk_queue_max_write_zeroes_sectors(q, UINT_MAX >> lo_bits);

	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);

}
@@ -918,6 +929,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, 


	lo->use_dio = false;

	lo->lo_blocksize = lo_blocksize;

	lo->lo_logical_blocksize = 512;

	lo->lo_device = bdev;

	lo->lo_flags = lo_flags;

	lo->lo_backing_file = file;
@@ -1083,6 +1095,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 
	int err;

	struct loop_func_table *xfer;

	kuid_t uid = current_uid();

	int lo_flags = lo->lo_flags;



	if (lo->lo_encrypt_key_size &&

	    !uid_eq(lo->lo_key_owner, uid) &&
@@ -1115,9 +1128,26 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) 
	if (err)

		goto exit;



	if (info->lo_flags & LO_FLAGS_BLOCKSIZE) {

		if (!(lo->lo_flags & LO_FLAGS_BLOCKSIZE))

			lo->lo_logical_blocksize = 512;

		lo->lo_flags |= LO_FLAGS_BLOCKSIZE;

		if (LO_INFO_BLOCKSIZE(info) != 512 &&

		    LO_INFO_BLOCKSIZE(info) != 1024 &&

		    LO_INFO_BLOCKSIZE(info) != 2048 &&

		    LO_INFO_BLOCKSIZE(info) != 4096)

			return -EINVAL;

		if (LO_INFO_BLOCKSIZE(info) > lo->lo_blocksize)

			return -EINVAL;

	}



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

	    lo->lo_sizelimit != info->lo_sizelimit)

		if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) {

	    lo->lo_sizelimit != info->lo_sizelimit ||

	    lo->lo_flags != lo_flags ||

	    ((lo->lo_flags & LO_FLAGS_BLOCKSIZE) &&

	     lo->lo_logical_blocksize != LO_INFO_BLOCKSIZE(info))) {

		if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit,

				     LO_INFO_BLOCKSIZE(info)))

			err = -EFBIG;

			goto exit;

		}
@@ -1308,7 +1338,8 @@ static int loop_set_capacity(struct loop_device *lo) 
	if (unlikely(lo->lo_state != Lo_bound))

		return -ENXIO;



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

	return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit,

				lo->lo_logical_blocksize);

}



static int loop_set_dio(struct loop_device *lo, unsigned long arg)

drivers/block/loop.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ struct loop_device { 
	struct file *	lo_backing_file;

	struct block_device *lo_device;

	unsigned	lo_blocksize;

	unsigned	lo_logical_blocksize;

	void		*key_data; 



	gfp_t		old_gfp_mask;

include/uapi/linux/loop.h

+3 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ enum { 
	LO_FLAGS_AUTOCLEAR	= 4,

	LO_FLAGS_PARTSCAN	= 8,

	LO_FLAGS_DIRECT_IO	= 16,

	LO_FLAGS_BLOCKSIZE	= 32,

};



#include <asm/posix_types.h>	/* for __kernel_old_dev_t */
@@ -59,6 +60,8 @@ struct loop_info64 { 
	__u64		   lo_init[2];

};



#define LO_INFO_BLOCKSIZE(l) (l)->lo_init[0]



/*

 * Loop filter types

 */