From f2c6df7dbf9a60e1cd9941f9fb376d4d9ad1e8dd Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Thu, 8 Jun 2017 13:46:45 +0200 Subject: [PATCH] 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: Hannes Reinecke Signed-off-by: Jens Axboe --- drivers/block/loop.c | 43 +++++++++++++++++++++++++++++++++------ drivers/block/loop.h | 1 + include/uapi/linux/loop.h | 3 +++ 3 files changed, 41 insertions(+), 6 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index fc706adff6a4..4d376c10a97a 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -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) diff --git a/drivers/block/loop.h b/drivers/block/loop.h index fecd3f97ef8c..2c096b9a17b8 100644 --- a/drivers/block/loop.h +++ b/drivers/block/loop.h @@ -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; diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h index c8125ec1f4f2..a3960f98679c 100644 --- a/include/uapi/linux/loop.h +++ b/include/uapi/linux/loop.h @@ -22,6 +22,7 @@ enum { LO_FLAGS_AUTOCLEAR = 4, LO_FLAGS_PARTSCAN = 8, LO_FLAGS_DIRECT_IO = 16, + LO_FLAGS_BLOCKSIZE = 32, }; #include /* 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 */ -- 2.20.1