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block: vhdx - update log guid in header, and first write tracker

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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 <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Jeff Cody 2013-10-30 10:44:43 -04:00 committed by Stefan Hajnoczi
parent 0f48e8f097
commit c3906c5e82
2 changed files with 30 additions and 6 deletions
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30
block/vhdx.c
View file

@ -230,7 +230,7 @@ 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;
@ -262,6 +262,11 @@ 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). */
@ -294,16 +299,16 @@ 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;
}
@ -784,6 +789,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
s->bat = NULL;
s->first_visible_write = true;
qemu_co_mutex_init(&s->lock);
@ -864,7 +870,7 @@ 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;
}
@ -1010,6 +1016,18 @@ 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)
{

6
block/vhdx.h
View file

@ -361,6 +361,7 @@ typedef struct BDRVVHDXState {
VHDXBatEntry *bat;
uint64_t bat_offset;
bool first_visible_write;
MSGUID session_guid;
VHDXLogEntries log;
@ -373,6 +374,9 @@ 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);
@ -402,4 +406,6 @@ 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