[PATCH 1/4] loop: Enable correct physical blocksize

From: Hannes Reinecke
Date: Tue Nov 10 2015 - 03:13:54 EST


When running on files the physical blocksize is actually 4k,
so we should be announcing it as such. This is enabled with
a new LO_FLAGS_BLOCKSIZE flag value to the existing
loop_set_status ioctl.

Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/block/loop.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 423f4ca..e790487 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -233,6 +233,8 @@ 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)
+ blk_queue_physical_block_size(lo->lo_queue, lo->lo_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 */
@@ -1092,6 +1094,7 @@ 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) &&
@@ -1121,8 +1124,12 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
if (err)
return err;

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

--
1.8.5.6

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