[Qemu-devel] [PATCH 05/12] VMDK: add field BDRVVmdkState.desc_offset to hold descriptor offset

[Fam Zheng]

There are several occurrence of magic number 0x200 as the descriptor
offset within mono sparse image file. This is not the case for images
with separate descriptor file. So a field is added to BDRVVmdkState to
hold the correct value.

Signed-off-by: Fam Zheng <famc...@gmail.com>
---
 block/vmdk.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/block/vmdk.c b/block/vmdk.c
index e360156..b02a7b7 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -81,6 +81,7 @@ typedef struct VmdkExtent {
 } VmdkExtent;

 typedef struct BDRVVmdkState {
+    int desc_offset;
     int num_extents;
     VmdkExtent *extents;
 } BDRVVmdkState;
@@ -126,9 +127,9 @@ static uint32_t vmdk_read_cid(BlockDriverState
*bs, int parent)
     uint32_t cid;
     const char *p_name, *cid_str;
     size_t cid_str_size;
+    BDRVVmdkState *s = bs->opaque;

-    /* the descriptor offset = 0x200 */
-    if (bdrv_pread(bs->file, 0x200, desc, DESC_SIZE) != DESC_SIZE)
+    if (bdrv_pread(bs->file, s->desc_offset, desc, DESC_SIZE) != DESC_SIZE)
         return 0;

     if (parent) {
@@ -151,9 +152,9 @@ static int vmdk_write_cid(BlockDriverState *bs,
uint32_t cid)
 {
     char desc[DESC_SIZE], tmp_desc[DESC_SIZE];
     char *p_name, *tmp_str;
+    BDRVVmdkState *s = bs->opaque;

-    /* the descriptor offset = 0x200 */
-    if (bdrv_pread(bs->file, 0x200, desc, DESC_SIZE) != DESC_SIZE)
+    if (bdrv_pread(bs->file, s->desc_offset, desc, DESC_SIZE) != DESC_SIZE)
         return -1;

     tmp_str = strstr(desc,"parentCID");
@@ -164,7 +165,7 @@ static int vmdk_write_cid(BlockDriverState *bs,
uint32_t cid)
         pstrcat(desc, sizeof(desc), tmp_desc);
     }

-    if (bdrv_pwrite_sync(bs->file, 0x200, desc, DESC_SIZE) < 0)
+    if (bdrv_pwrite_sync(bs->file, s->desc_offset, desc, DESC_SIZE) < 0)
         return -1;
     return 0;
 }
@@ -352,9 +353,9 @@ static int vmdk_parent_open(BlockDriverState *bs)
 {
     char *p_name;
     char desc[DESC_SIZE];
+    BDRVVmdkState *s = bs->opaque;

-    /* the descriptor offset = 0x200 */
-    if (bdrv_pread(bs->file, 0x200, desc, DESC_SIZE) != DESC_SIZE)
+    if (bdrv_pread(bs->file, s->desc_offset, desc, DESC_SIZE) != DESC_SIZE)
         return -1;

     if ((p_name = strstr(desc,"parentFileNameHint")) != NULL) {
@@ -441,6 +442,7 @@ static int vmdk_open_vmdk3(BlockDriverState *bs, int flags)
     extent->l1_backup_table_offset = 0;
     extent->l1_entry_sectors = extent->l2_size * extent->cluster_sectors;
     bs->total_sectors = extent->sectors;
+    s->desc_offset = 0x200;
     if (vmdk_init_tables(bs, extent)) {
         goto fail;
     }
@@ -477,6 +479,7 @@ static int vmdk_open_vmdk4(BlockDriverState *bs, int flags)
     extent->l1_table_offset = le64_to_cpu(header.rgd_offset) << 9;
     extent->l1_backup_table_offset = le64_to_cpu(header.gd_offset) << 9;

+    s->desc_offset = 0x200;
     // try to open parent images, if exist
     if (vmdk_parent_open(bs) != 0) {
         goto fail;