From 220843fb6a0c3f9523b1f20a2b30ea104dba55ad Mon Sep 17 00:00:00 2001
From: detworam <detworam@gmail.com>
Date: Wed, 24 May 2017 13:09:37 -0400
Subject: [PATCH] add ability to set block size

---
 buse.c | 15 +++++++++++++--
 buse.h |  3 +++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/buse.c b/buse.c
index 5fada2e..4d52fe3 100644
--- a/buse.c
+++ b/buse.c
@@ -103,8 +103,19 @@ int buse_main(const char* dev_file, const struct buse_operations *aop, void *use
     return 1;
   }
 
-  err = ioctl(nbd, NBD_SET_SIZE, aop->size);
-  assert(err != -1);
+  if (aop->blksize) {
+    err = ioctl(nbd, NBD_SET_BLKSIZE, aop->blksize);
+    assert(err != -1);
+  }
+  if (aop->size) {
+    err = ioctl(nbd, NBD_SET_SIZE, aop->size);
+    assert(err != -1);
+  }
+  if (aop->size_blocks) {
+    err = ioctl(nbd, NBD_SET_SIZE_BLOCKS, aop->size_blocks);
+    assert(err != -1);
+  }
+
   err = ioctl(nbd, NBD_CLEAR_SOCK);
   assert(err != -1);
 
diff --git a/buse.h b/buse.h
index 4cedf1b..c3d379c 100644
--- a/buse.h
+++ b/buse.h
@@ -17,7 +17,10 @@ extern "C" {
     int (*flush)(void *userdata);
     int (*trim)(u_int64_t from, u_int32_t len, void *userdata);
 
+    // either set size, OR set both blksize and size_blocks
     u_int64_t size;
+    u_int32_t blksize;
+    u_int64_t size_blocks;
   };
 
   int buse_main(const char* dev_file, const struct buse_operations *bop, void *userdata);