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vmdk: Add option to create zeroed-grain image 

Add image create option "zeroed-grain" to enable zeroed-grain GTE
feature of vmdk sparse extents. When this option is on, header version
of newly created extent will be 2 and VMDK4_FLAG_ZERO_GRAIN flag bit
will be set.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2013-05-02 10:25:24 +08:00 committed by Stefan Hajnoczi
parent 14ead646fe
commit 69e0b6dfa4
1 changed files with 17 additions and 5 deletions
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22
block/vmdk.c
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@ -48,6 +48,8 @@
#define VMDK_UNALLOC (-2)
#define VMDK_ZEROED (-3)
#define BLOCK_OPT_ZEROED_GRAIN "zeroed_grain"
typedef struct {
uint32_t version;
uint32_t flags;
@ -1262,7 +1264,7 @@ static coroutine_fn int vmdk_co_write(BlockDriverState *bs, int64_t sector_num,
static int vmdk_create_extent(const char *filename, int64_t filesize,
bool flat, bool compress)
bool flat, bool compress, bool zeroed_grain)
{
int ret, i;
int fd = 0;
@ -1284,9 +1286,10 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
}
magic = cpu_to_be32(VMDK4_MAGIC);
memset(&header, 0, sizeof(header));
header.version = 1;
header.flags =
3 | (compress ? VMDK4_FLAG_COMPRESS | VMDK4_FLAG_MARKER : 0);
header.version = zeroed_grain ? 2 : 1;
header.flags = 3
| (compress ? VMDK4_FLAG_COMPRESS | VMDK4_FLAG_MARKER : 0)
| (zeroed_grain ? VMDK4_FLAG_ZERO_GRAIN : 0);
header.compressAlgorithm = compress ? VMDK4_COMPRESSION_DEFLATE : 0;
header.capacity = filesize / 512;
header.granularity = 128;
@ -1467,6 +1470,7 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
char parent_desc_line[BUF_SIZE] = "";
uint32_t parent_cid = 0xffffffff;
uint32_t number_heads = 16;
bool zeroed_grain = false;
const char desc_template[] =
"# Disk DescriptorFile\n"
"version=1\n"
@ -1502,6 +1506,8 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
flags |= options->value.n ? BLOCK_FLAG_COMPAT6 : 0;
} else if (!strcmp(options->name, BLOCK_OPT_SUBFMT)) {
fmt = options->value.s;
} else if (!strcmp(options->name, BLOCK_OPT_ZEROED_GRAIN)) {
zeroed_grain |= options->value.n;
}
options++;
}
@ -1588,7 +1594,8 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options)
snprintf(ext_filename, sizeof(ext_filename), "%s%s",
path, desc_filename);
if (vmdk_create_extent(ext_filename, size, flat, compress)) {
if (vmdk_create_extent(ext_filename, size,
flat, compress, zeroed_grain)) {
return -EINVAL;
}
filesize -= size;
@ -1714,6 +1721,11 @@ static QEMUOptionParameter vmdk_create_options[] = {
"VMDK flat extent format, can be one of "
"{monolithicSparse (default) | monolithicFlat | twoGbMaxExtentSparse | twoGbMaxExtentFlat | streamOptimized} "
},
{
.name = BLOCK_OPT_ZEROED_GRAIN,
.type = OPT_FLAG,
.help = "Enable efficient zero writes using the zeroed-grain GTE feature"
},
{ NULL }
};