Allow tracking of first file write in the VHDX image, as well as
the ability to update the GUID in the header. This is in preparation
for log support.
Signed-off-by: Jeff Cody <jc...@redhat.com>
---
block/vhdx.c | 30 ++++++++++++++++++++++++------
block/vhdx.h | 6 ++++++
2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/block/vhdx.c b/block/vhdx.c
index 15a4d1d..4dc056b 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -229,7 +229,7 @@ static int vhdx_probe(const uint8_t *buf, int buf_size,
const char *filename)
* - non-current header is updated with largest sequence number
*/
static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s,
- bool generate_data_write_guid)
+ bool generate_data_write_guid, MSGUID *log_guid)
{
int ret = 0;
int hdr_idx = 0;
@@ -261,6 +261,11 @@ static int vhdx_update_header(BlockDriverState *bs,
BDRVVHDXState *s,
vhdx_guid_generate(&inactive_header->data_write_guid);
}
+ /* update the log guid if present */
+ if (log_guid) {
+ inactive_header->log_guid = *log_guid;
+ }
+
/* the header checksum is not over just the packed size of VHDXHeader,
* but rather over the entire 'reserved' range for the header, which is
* 4KB (VHDX_HEADER_SIZE). */
@@ -293,16 +298,16 @@ exit:
* The VHDX spec calls for header updates to be performed twice, so that both
* the current and non-current header have valid info
*/
-static int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
- bool generate_data_write_guid)
+int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s,
+ bool generate_data_write_guid, MSGUID *log_guid)
{
int ret;
- ret = vhdx_update_header(bs, s, generate_data_write_guid);
+ ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
if (ret < 0) {
return ret;
}
- ret = vhdx_update_header(bs, s, generate_data_write_guid);
+ ret = vhdx_update_header(bs, s, generate_data_write_guid, log_guid);
return ret;
}
@@ -782,6 +787,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options,
int flags)
s->bat = NULL;
+ s->first_visible_write = true;
qemu_co_mutex_init(&s->lock);
@@ -862,7 +868,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options,
int flags)
}
if (flags & BDRV_O_RDWR) {
- ret = vhdx_update_headers(bs, s, false);
+ ret = vhdx_update_headers(bs, s, false, NULL);
if (ret < 0) {
goto fail;
}
@@ -1002,6 +1008,18 @@ exit:
+/* Per the spec, on the first write of guest-visible data to the file the
+ * data write guid must be updated in the header */
+int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s)
+{
+ int ret = 0;
+ if (s->first_visible_write) {
+ s->first_visible_write = false;
+ ret = vhdx_update_headers(bs, s, true, NULL);
+ }
+ return ret;
+}
+
static coroutine_fn int vhdx_co_writev(BlockDriverState *bs, int64_t
sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
diff --git a/block/vhdx.h b/block/vhdx.h
index 89d9a78..8c61bfd 100644
--- a/block/vhdx.h
+++ b/block/vhdx.h
@@ -361,6 +361,7 @@ typedef struct BDRVVHDXState {
VHDXBatEntry *bat;
uint64_t bat_offset;
+ bool first_visible_write;
MSGUID session_guid;
VHDXLogEntries log;
@@ -372,6 +373,9 @@ typedef struct BDRVVHDXState {
void vhdx_guid_generate(MSGUID *guid);
+int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw,
+ MSGUID *log_guid);
+
uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset);
uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
int crc_offset);
@@ -401,4 +405,6 @@ void vhdx_log_data_le_export(VHDXLogDataSector *d);
void vhdx_log_entry_hdr_le_import(VHDXLogEntryHeader *hdr);
void vhdx_log_entry_hdr_le_export(VHDXLogEntryHeader *hdr);
+int vhdx_user_visible_write(BlockDriverState *bs, BDRVVHDXState *s);
+
#endif
--
1.8.1.4
