On Fri, Apr 07, 2017 at 08:58:58AM +0200, Hannes Reinecke wrote: > 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.
Actually this UAPI flag is only for setting logical block size. > > Signed-off-by: Hannes Reinecke <[email protected]> > --- > drivers/block/loop.c | 36 +++++++++++++++++++++++++++++++----- > drivers/block/loop.h | 1 + > include/uapi/linux/loop.h | 3 +++ > 3 files changed, 35 insertions(+), 5 deletions(-) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index 81b3900..f098681 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 @@ static void __loop_update_dio(struct loop_device *lo, > bool dio) > 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); > + } We can move setting physical block size into loop_set_fd(), and set 512 bytes as default logical block size in loop_set_fd() too. > 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 */ > @@ -814,6 +821,7 @@ 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 = blksize_bits(lo->lo_logical_blocksize); > > /* > * We use punch hole to reclaim the free space used by the > @@ -833,7 +841,7 @@ 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_discard_sectors(q, UINT_MAX >> lo_bits); > q->limits.discard_zeroes_data = 1; > queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q); > } > @@ -922,6 +930,7 @@ 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; It isn't enough to just this local vaiable as 512 here, since the last logical block size is still kept in queue's setting. > lo->lo_device = bdev; > lo->lo_flags = lo_flags; > lo->lo_backing_file = file; > @@ -1087,6 +1096,7 @@ static int loop_clr_fd(struct loop_device *lo) > 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) && > @@ -1119,9 +1129,24 @@ static int loop_clr_fd(struct loop_device *lo) > if (err) > goto exit; > > + if (info->lo_flags & LO_FLAGS_BLOCKSIZE) { > + 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, > + info->lo_init[0])) > err = -EFBIG; > goto exit; > } > @@ -1312,7 +1337,8 @@ 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 fb2237c..579f2f7 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 c8125ec..a3960f9 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 <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 > */ > -- > 1.8.5.6 > -- Ming
