On 04/07/2017 11:34 AM, Ming Lei wrote: > 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. > Hmm? No, we're setting the physical blocksize, too. Or am I missing something?
>> >> 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. > Okay. >> 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. > Right. Will be updating the queue setting, too. Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)
