[PATCH 4/4] loop: Pass logical blocksize in 'lo_init[0]' ioctl field

From: Hannes Reinecke
Date: Mon Oct 31 2016 - 15:38:15 EST


The current LOOP_SET_STATUS64 ioctl has two unused fields
'init[2]', which can be used in conjunction with the
LO_FLAGS_BLOCKSIZE flag to pass in the new logical blocksize.

Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/block/loop.c | 24 +++++++++++++++++++-----
1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index a863667..9ad56bf 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;
@@ -234,6 +235,7 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
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);
@@ -1124,13 +1126,24 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
if (err)
return err;

- if (info->lo_flags & LO_FLAGS_BLOCKSIZE)
+ if (info->lo_flags & LO_FLAGS_BLOCKSIZE) {
lo->lo_flags |= LO_FLAGS_BLOCKSIZE;
+ if ((info->lo_init[0] != 512) &&
+ (info->lo_init[0] != 1024) &&
+ (info->lo_init[0] != 2048) &&
+ (info->lo_init[0] != 4096))
+ return -EINVAL;
+ if (info->lo_init[0] > lo->lo_blocksize)
+ return -EINVAL;
+ }

if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit ||
- lo->lo_flags != lo_flags)
- if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
+ lo->lo_flags != lo_flags ||
+ ((lo->lo_flags & LO_FLAGS_BLOCKSIZE) &&
+ (lo->lo_logical_blocksize != info->lo_init[0])))
+ if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit,
+ info->lo_init[0]))
return -EFBIG;

loop_config_discard(lo);
@@ -1315,7 +1328,8 @@ 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)
--
2.6.6