[Qemu-devel] [PATCH v2 3/4] block: qcow2 - used QEMU_PACKED for on-disk structures

[Jeff Cody]

QCowHeader and QCowExtension are structs that reside in the on-disk
image format, and are read and written directly via bdrv_pread()/write(),
and as such should be packed to avoid any unintentional struct padding.

Signed-off-by: Jeff Cody <address@hidden>
---
 block/qcow2.c | 2 +-
 block/qcow2.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index 318d95d..4a9888c 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -52,7 +52,7 @@
 typedef struct {
     uint32_t magic;
     uint32_t len;
-} QCowExtension;
+} QEMU_PACKED QCowExtension;
 
 #define  QCOW2_EXT_MAGIC_END 0
 #define  QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
diff --git a/block/qcow2.h b/block/qcow2.h
index c90e5d6..455e38d 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -86,7 +86,7 @@ typedef struct QCowHeader {
 
     uint32_t refcount_order;
     uint32_t header_length;
-} QCowHeader;
+} QEMU_PACKED QCowHeader;
 
 typedef struct QCowSnapshot {
     uint64_t l1_table_offset;
-- 
1.8.3.1