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

[Hannes Reinecke]

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 <h...@suse.de>
---
 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