|
| From: | Charles Arnold |
| Subject: | [Qemu-devel] [PATCH] block: Add support for vpc Fixed Disk type |
| Date: | Tue, 31 Jan 2012 12:03:44 -0700 |
The Virtual Hard Disk Image Format Specification allows for three
types of hard disk formats, Fixed, Dynamic, and Differencing. Qemu
currently only supports Dynamic disks. This patch adds support for
the Fixed Disk format.
Usage:
Example 1: qemu-img create -f vpc -o type=fixed <filename> [size]
Example 2: qemu-img convert -O vpc -o type=fixed <input filename> <output
filename>
While it is also allowed to specify '-o type=dynamic', the default disk type
remains Dynamic and is what is used when the type is left unspecified.
Signed-off-by: Charles Arnold <address@hidden>
diff --git a/block/vpc.c b/block/vpc.c
index 89a5ee2..bfe5f7b 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -160,6 +160,7 @@ static int vpc_open(BlockDriverState *bs, int flags)
struct vhd_dyndisk_header* dyndisk_header;
uint8_t buf[HEADER_SIZE];
uint32_t checksum;
+ int disk_type = VHD_DYNAMIC;
int err = -1;
if (bdrv_pread(bs->file, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
@@ -167,7 +168,16 @@ static int vpc_open(BlockDriverState *bs, int flags)
footer = (struct vhd_footer*) s->footer_buf;
if (strncmp(footer->creator, "conectix", 8))
- goto fail;
+ {
+ int64_t offset = bdrv_getlength(bs->file);
+ // If a fixed disk, the footer is found only at the end of the file
+ if (bdrv_pread(bs->file, offset-HEADER_SIZE, s->footer_buf,
HEADER_SIZE)
+ != HEADER_SIZE)
+ goto fail;
+ if (strncmp(footer->creator, "conectix", 8))
+ goto fail;
+ disk_type = VHD_FIXED;
+ }
checksum = be32_to_cpu(footer->checksum);
footer->checksum = 0;
@@ -186,6 +196,14 @@ static int vpc_open(BlockDriverState *bs, int flags)
goto fail;
}
+ // The footer is all that is needed for fixed disks.
+ if (disk_type == VHD_FIXED) {
+ // The fixed disk format doesn't use footer->data_offset but it
+ // should be initialized
+ footer->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFF);
+ return 0;
+ }
+
if (bdrv_pread(bs->file, be64_to_cpu(footer->data_offset), buf,
HEADER_SIZE)
!= HEADER_SIZE)
goto fail;
@@ -533,7 +551,7 @@ static int calculate_geometry(int64_t total_sectors,
uint16_t* cyls,
return 0;
}
-static int vpc_create(const char *filename, QEMUOptionParameter *options)
+static int vpc_create_dynamic_disk(const char *filename, int64_t total_size)
{
uint8_t buf[1024];
struct vhd_footer* footer = (struct vhd_footer*) buf;
@@ -544,13 +562,9 @@ static int vpc_create(const char *filename,
QEMUOptionParameter *options)
uint8_t heads = 0;
uint8_t secs_per_cyl = 0;
size_t block_size, num_bat_entries;
- int64_t total_sectors = 0;
+ int64_t total_sectors = total_size / BDRV_SECTOR_SIZE;
int ret = -EIO;
- // Read out options
- total_sectors = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n /
- BDRV_SECTOR_SIZE;
-
// Create the file
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
if (fd < 0)
@@ -657,6 +671,101 @@ static int vpc_create(const char *filename,
QEMUOptionParameter *options)
return ret;
}
+static int vpc_create_fixed_disk(const char *filename, int64_t total_size)
+{
+ uint8_t buf[1024];
+ struct vhd_footer* footer = (struct vhd_footer*) buf;
+ int fd;
+ uint16_t cyls = 0;
+ uint8_t heads = 0;
+ uint8_t secs_per_cyl = 0;
+ int64_t total_sectors = total_size / BDRV_SECTOR_SIZE;
+ int ret = -EIO;
+
+ // Create the file
+ fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
+ if (fd < 0)
+ return -EIO;
+
+ /* Calculate matching total_size and geometry. */
+ if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl)) {
+ ret = -EFBIG;
+ goto fail;
+ }
+ total_sectors = (int64_t) cyls * heads * secs_per_cyl;
+
+ // Prepare the Hard Disk Footer
+ memset(buf, 0, 1024);
+
+ memcpy(footer->creator, "conectix", 8);
+ // TODO Check if "qemu" creator_app is ok for VPC
+ memcpy(footer->creator_app, "qemu", 4);
+ memcpy(footer->creator_os, "Wi2k", 4);
+
+ footer->features = be32_to_cpu(0x02);
+ footer->version = be32_to_cpu(0x00010000);
+ footer->data_offset = be64_to_cpu(0xFFFFFFFFFFFFFFFF);
+ footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
+
+ // Version of Virtual PC 2007
+ footer->major = be16_to_cpu(0x0005);
+ footer->minor =be16_to_cpu(0x0003);
+ footer->orig_size = be64_to_cpu(total_size);
+ footer->size = be64_to_cpu(total_size);
+ footer->cyls = be16_to_cpu(cyls);
+ footer->heads = heads;
+ footer->secs_per_cyl = secs_per_cyl;
+
+ footer->type = be32_to_cpu(VHD_FIXED);
+
+ // TODO uuid is missing
+
+ footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
+
+ total_size += 512;
+ if (ftruncate(fd, total_size) != 0) {
+ ret = -errno;
+ goto fail;
+ }
+ if (lseek(fd, -512, SEEK_END) < 0) {
+ goto fail;
+ }
+ if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE) {
+ goto fail;
+ }
+
+ ret = 0;
+
+ fail:
+ close(fd);
+ return ret;
+}
+
+static int vpc_create(const char *filename, QEMUOptionParameter *options)
+{
+ int64_t total_size = 0;
+ QEMUOptionParameter *disk_type_param;
+ int ret = -EIO;
+
+ // Read out options
+ total_size = get_option_parameter(options, BLOCK_OPT_SIZE)->value.n;
+
+ disk_type_param = get_option_parameter(options, BLOCK_OPT_TYPE);
+ if (disk_type_param && disk_type_param->value.s) {
+ if (!strcmp(disk_type_param->value.s, "dynamic") ) {
+ ret = vpc_create_dynamic_disk(filename, total_size);
+ }
+ else if (!strcmp(disk_type_param->value.s, "fixed") ) {
+ ret = vpc_create_fixed_disk(filename, total_size);
+ }
+ else
+ ret = -EINVAL;
+ } else {
+ ret = vpc_create_dynamic_disk(filename, total_size);
+ }
+ return ret;
+}
+
static void vpc_close(BlockDriverState *bs)
{
BDRVVPCState *s = bs->opaque;
@@ -675,6 +784,13 @@ static QEMUOptionParameter vpc_create_options[] = {
.type = OPT_SIZE,
.help = "Virtual disk size"
},
+ {
+ .name = BLOCK_OPT_TYPE,
+ .type = OPT_STRING,
+ .help =
+ "Type of virtual hard disk format. Supported formats are "
+ "{dynamic (default) | fixed} "
+ },
{ NULL }
};
diff --git a/block_int.h b/block_int.h
index 311bd2a..6d6cc96 100644
--- a/block_int.h
+++ b/block_int.h
@@ -50,6 +50,7 @@
#define BLOCK_OPT_TABLE_SIZE "table_size"
#define BLOCK_OPT_PREALLOC "preallocation"
#define BLOCK_OPT_SUBFMT "subformat"
+#define BLOCK_OPT_TYPE "type"
typedef struct BdrvTrackedRequest BdrvTrackedRequest;
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