New multiple snapshot support for VMDK, by Igor Lvovsky.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2352 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths 2007-01-24 21:05:24 +00:00
parent b29a0341d7
commit 5f4da8c0f3

View file

@ -22,6 +22,7 @@
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "vl.h"
#include "block_int.h"
@ -59,7 +60,7 @@ typedef struct {
#define L2_CACHE_SIZE 16
typedef struct BDRVVmdkState {
int fd;
BlockDriverState *hd;
int64_t l1_table_offset;
int64_t l1_backup_table_offset;
uint32_t *l1_table;
@ -73,6 +74,7 @@ typedef struct BDRVVmdkState {
uint32_t l2_cache_counts[L2_CACHE_SIZE];
unsigned int cluster_sectors;
uint32_t parent_cid;
} BDRVVmdkState;
static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
@ -89,27 +91,278 @@ static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
return 0;
}
#define CHECK_CID 1
#define SECTOR_SIZE 512
#define DESC_SIZE 20*SECTOR_SIZE // 20 sectors of 512 bytes each
#define HEADER_SIZE 512 // first sector of 512 bytes
static uint32_t vmdk_read_cid(BlockDriverState *bs, int parent)
{
BDRVVmdkState *s = bs->opaque;
char desc[DESC_SIZE];
uint32_t cid;
char *p_name, *cid_str;
size_t cid_str_size;
/* the descriptor offset = 0x200 */
if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
return 0;
if (parent) {
cid_str = "parentCID";
cid_str_size = sizeof("parentCID");
} else {
cid_str = "CID";
cid_str_size = sizeof("CID");
}
if ((p_name = strstr(desc,cid_str)) != 0) {
p_name += cid_str_size;
sscanf(p_name,"%x",&cid);
}
return cid;
}
static int vmdk_write_cid(BlockDriverState *bs, uint32_t cid)
{
BDRVVmdkState *s = bs->opaque;
char desc[DESC_SIZE], tmp_desc[DESC_SIZE];
char *p_name, *tmp_str;
/* the descriptor offset = 0x200 */
if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
return -1;
tmp_str = strstr(desc,"parentCID");
strcpy(tmp_desc, tmp_str);
if ((p_name = strstr(desc,"CID")) != 0) {
p_name += sizeof("CID");
sprintf(p_name,"%x\n",cid);
strcat(desc,tmp_desc);
}
if (bdrv_pwrite(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
return -1;
return 0;
}
static int vmdk_is_cid_valid(BlockDriverState *bs)
{
#ifdef CHECK_CID
BDRVVmdkState *s = bs->opaque;
BlockDriverState *p_bs = s->hd->backing_hd;
uint32_t cur_pcid;
if (p_bs) {
cur_pcid = vmdk_read_cid(p_bs,0);
if (s->parent_cid != cur_pcid)
// CID not valid
return 0;
}
#endif
// CID valid
return 1;
}
static int vmdk_snapshot_create(const char *filename, const char *backing_file)
{
int snp_fd, p_fd;
uint32_t p_cid;
char *p_name, *gd_buf, *rgd_buf;
const char *real_filename, *temp_str;
VMDK4Header header;
uint32_t gde_entries, gd_size;
int64_t gd_offset, rgd_offset, capacity, gt_size;
char p_desc[DESC_SIZE], s_desc[DESC_SIZE], hdr[HEADER_SIZE];
char *desc_template =
"# Disk DescriptorFile\n"
"version=1\n"
"CID=%x\n"
"parentCID=%x\n"
"createType=\"monolithicSparse\"\n"
"parentFileNameHint=\"%s\"\n"
"\n"
"# Extent description\n"
"RW %lu SPARSE \"%s\"\n"
"\n"
"# The Disk Data Base \n"
"#DDB\n"
"\n";
snp_fd = open(filename, O_RDWR | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE, 0644);
if (snp_fd < 0)
return -1;
p_fd = open(backing_file, O_RDONLY | O_BINARY | O_LARGEFILE);
if (p_fd < 0) {
close(snp_fd);
return -1;
}
/* read the header */
if (lseek(p_fd, 0x0, SEEK_SET) == -1)
goto fail;
if (read(p_fd, hdr, HEADER_SIZE) != HEADER_SIZE)
goto fail;
/* write the header */
if (lseek(snp_fd, 0x0, SEEK_SET) == -1)
goto fail;
if (write(snp_fd, hdr, HEADER_SIZE) == -1)
goto fail;
memset(&header, 0, sizeof(header));
memcpy(&header,&hdr[4], sizeof(header)); // skip the VMDK4_MAGIC
ftruncate(snp_fd, header.grain_offset << 9);
/* the descriptor offset = 0x200 */
if (lseek(p_fd, 0x200, SEEK_SET) == -1)
goto fail;
if (read(p_fd, p_desc, DESC_SIZE) != DESC_SIZE)
goto fail;
if ((p_name = strstr(p_desc,"CID")) != 0) {
p_name += sizeof("CID");
sscanf(p_name,"%x",&p_cid);
}
real_filename = filename;
if ((temp_str = strrchr(real_filename, '\\')) != NULL)
real_filename = temp_str + 1;
if ((temp_str = strrchr(real_filename, '/')) != NULL)
real_filename = temp_str + 1;
if ((temp_str = strrchr(real_filename, ':')) != NULL)
real_filename = temp_str + 1;
sprintf(s_desc, desc_template, p_cid, p_cid, backing_file
, (uint32_t)header.capacity, real_filename);
/* write the descriptor */
if (lseek(snp_fd, 0x200, SEEK_SET) == -1)
goto fail;
if (write(snp_fd, s_desc, strlen(s_desc)) == -1)
goto fail;
gd_offset = header.gd_offset * SECTOR_SIZE; // offset of GD table
rgd_offset = header.rgd_offset * SECTOR_SIZE; // offset of RGD table
capacity = header.capacity * SECTOR_SIZE; // Extent size
/*
* Each GDE span 32M disk, means:
* 512 GTE per GT, each GTE points to grain
*/
gt_size = (int64_t)header.num_gtes_per_gte * header.granularity * SECTOR_SIZE;
if (!gt_size)
goto fail;
gde_entries = (uint32_t)(capacity / gt_size); // number of gde/rgde
gd_size = gde_entries * sizeof(uint32_t);
/* write RGD */
rgd_buf = qemu_malloc(gd_size);
if (!rgd_buf)
goto fail;
if (lseek(p_fd, rgd_offset, SEEK_SET) == -1)
goto fail_rgd;
if (read(p_fd, rgd_buf, gd_size) != gd_size)
goto fail_rgd;
if (lseek(snp_fd, rgd_offset, SEEK_SET) == -1)
goto fail_rgd;
if (write(snp_fd, rgd_buf, gd_size) == -1)
goto fail_rgd;
qemu_free(rgd_buf);
/* write GD */
gd_buf = qemu_malloc(gd_size);
if (!gd_buf)
goto fail_rgd;
if (lseek(p_fd, gd_offset, SEEK_SET) == -1)
goto fail_gd;
if (read(p_fd, gd_buf, gd_size) != gd_size)
goto fail_gd;
if (lseek(snp_fd, gd_offset, SEEK_SET) == -1)
goto fail_gd;
if (write(snp_fd, gd_buf, gd_size) == -1)
goto fail_gd;
qemu_free(gd_buf);
close(p_fd);
close(snp_fd);
return 0;
fail_gd:
qemu_free(gd_buf);
fail_rgd:
qemu_free(rgd_buf);
fail:
close(p_fd);
close(snp_fd);
return -1;
}
static void vmdk_parent_close(BlockDriverState *bs)
{
if (bs->backing_hd)
bdrv_close(bs->backing_hd);
}
static int vmdk_parent_open(BlockDriverState *bs, const char * filename)
{
BDRVVmdkState *s = bs->opaque;
char *p_name;
char desc[DESC_SIZE];
char parent_img_name[1024];
/* the descriptor offset = 0x200 */
if (bdrv_pread(s->hd, 0x200, desc, DESC_SIZE) != DESC_SIZE)
return -1;
if ((p_name = strstr(desc,"parentFileNameHint")) != 0) {
char *end_name;
struct stat file_buf;
p_name += sizeof("parentFileNameHint") + 1;
if ((end_name = strchr(p_name,'\"')) == 0)
return -1;
strncpy(s->hd->backing_file, p_name, end_name - p_name);
if (stat(s->hd->backing_file, &file_buf) != 0) {
path_combine(parent_img_name, sizeof(parent_img_name),
filename, s->hd->backing_file);
} else {
strcpy(parent_img_name, s->hd->backing_file);
}
s->hd->backing_hd = bdrv_new("");
if (!s->hd->backing_hd) {
failure:
bdrv_close(s->hd);
return -1;
}
if (bdrv_open(s->hd->backing_hd, parent_img_name, 0) < 0)
goto failure;
}
return 0;
}
static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
{
BDRVVmdkState *s = bs->opaque;
int fd, i;
uint32_t magic;
int l1_size;
int l1_size, i, ret;
fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
if (fd < 0) {
fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
if (fd < 0)
return -1;
bs->read_only = 1;
}
if (read(fd, &magic, sizeof(magic)) != sizeof(magic))
ret = bdrv_file_open(&s->hd, filename, flags);
if (ret < 0)
return ret;
if (bdrv_pread(s->hd, 0, &magic, sizeof(magic)) != sizeof(magic))
goto fail;
magic = be32_to_cpu(magic);
if (magic == VMDK3_MAGIC) {
VMDK3Header header;
if (read(fd, &header, sizeof(header)) !=
sizeof(header))
if (bdrv_pread(s->hd, sizeof(magic), &header, sizeof(header)) != sizeof(header))
goto fail;
s->cluster_sectors = le32_to_cpu(header.granularity);
s->l2_size = 1 << 9;
@ -120,8 +373,8 @@ static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
s->l1_entry_sectors = s->l2_size * s->cluster_sectors;
} else if (magic == VMDK4_MAGIC) {
VMDK4Header header;
if (read(fd, &header, sizeof(header)) != sizeof(header))
if (bdrv_pread(s->hd, sizeof(magic), &header, sizeof(header)) != sizeof(header))
goto fail;
bs->total_sectors = le64_to_cpu(header.capacity);
s->cluster_sectors = le64_to_cpu(header.granularity);
@ -133,17 +386,22 @@ static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
/ s->l1_entry_sectors;
s->l1_table_offset = le64_to_cpu(header.rgd_offset) << 9;
s->l1_backup_table_offset = le64_to_cpu(header.gd_offset) << 9;
// try to open parent images, if exist
if (vmdk_parent_open(bs, filename) != 0)
goto fail;
// write the CID once after the image creation
s->parent_cid = vmdk_read_cid(bs,1);
} else {
goto fail;
}
/* read the L1 table */
l1_size = s->l1_size * sizeof(uint32_t);
s->l1_table = qemu_malloc(l1_size);
if (!s->l1_table)
goto fail;
if (lseek(fd, s->l1_table_offset, SEEK_SET) == -1)
goto fail;
if (read(fd, s->l1_table, l1_size) != l1_size)
if (bdrv_pread(s->hd, s->l1_table_offset, s->l1_table, l1_size) != l1_size)
goto fail;
for(i = 0; i < s->l1_size; i++) {
le32_to_cpus(&s->l1_table[i]);
@ -153,9 +411,7 @@ static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
s->l1_backup_table = qemu_malloc(l1_size);
if (!s->l1_backup_table)
goto fail;
if (lseek(fd, s->l1_backup_table_offset, SEEK_SET) == -1)
goto fail;
if (read(fd, s->l1_backup_table, l1_size) != l1_size)
if (bdrv_pread(s->hd, s->l1_backup_table_offset, s->l1_backup_table, l1_size) != l1_size)
goto fail;
for(i = 0; i < s->l1_size; i++) {
le32_to_cpus(&s->l1_backup_table[i]);
@ -165,16 +421,43 @@ static int vmdk_open(BlockDriverState *bs, const char *filename, int flags)
s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint32_t));
if (!s->l2_cache)
goto fail;
s->fd = fd;
return 0;
fail:
qemu_free(s->l1_backup_table);
qemu_free(s->l1_table);
qemu_free(s->l2_cache);
close(fd);
bdrv_delete(s->hd);
return -1;
}
static uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate);
static int get_whole_cluster(BlockDriverState *bs, uint64_t cluster_offset,
uint64_t offset, int allocate)
{
uint64_t parent_cluster_offset;
BDRVVmdkState *s = bs->opaque;
uint8_t whole_grain[s->cluster_sectors*512]; // 128 sectors * 512 bytes each = grain size 64KB
// we will be here if it's first write on non-exist grain(cluster).
// try to read from parent image, if exist
if (s->hd->backing_hd) {
BDRVVmdkState *ps = s->hd->backing_hd->opaque;
if (!vmdk_is_cid_valid(bs))
return -1;
parent_cluster_offset = get_cluster_offset(s->hd->backing_hd, offset, allocate);
if (bdrv_pread(ps->hd, parent_cluster_offset, whole_grain, ps->cluster_sectors*512) !=
ps->cluster_sectors*512)
return -1;
if (bdrv_pwrite(s->hd, cluster_offset << 9, whole_grain, sizeof(whole_grain)) !=
sizeof(whole_grain))
return -1;
}
return 0;
}
static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t offset, int allocate)
{
@ -212,34 +495,41 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
}
}
l2_table = s->l2_cache + (min_index * s->l2_size);
lseek(s->fd, (int64_t)l2_offset * 512, SEEK_SET);
if (read(s->fd, l2_table, s->l2_size * sizeof(uint32_t)) !=
s->l2_size * sizeof(uint32_t))
if (bdrv_pread(s->hd, (int64_t)l2_offset * 512, l2_table, s->l2_size * sizeof(uint32_t)) !=
s->l2_size * sizeof(uint32_t))
return 0;
s->l2_cache_offsets[min_index] = l2_offset;
s->l2_cache_counts[min_index] = 1;
found:
l2_index = ((offset >> 9) / s->cluster_sectors) % s->l2_size;
cluster_offset = le32_to_cpu(l2_table[l2_index]);
if (!cluster_offset) {
struct stat file_buf;
if (!allocate)
return 0;
cluster_offset = lseek(s->fd, 0, SEEK_END);
ftruncate(s->fd, cluster_offset + (s->cluster_sectors << 9));
stat(s->hd->filename, &file_buf);
cluster_offset = file_buf.st_size;
bdrv_truncate(s->hd, cluster_offset + (s->cluster_sectors << 9));
cluster_offset >>= 9;
/* update L2 table */
tmp = cpu_to_le32(cluster_offset);
l2_table[l2_index] = tmp;
lseek(s->fd, ((int64_t)l2_offset * 512) + (l2_index * sizeof(tmp)), SEEK_SET);
if (write(s->fd, &tmp, sizeof(tmp)) != sizeof(tmp))
if (bdrv_pwrite(s->hd, ((int64_t)l2_offset * 512) + (l2_index * sizeof(tmp)),
&tmp, sizeof(tmp)) != sizeof(tmp))
return 0;
/* update backup L2 table */
if (s->l1_backup_table_offset != 0) {
l2_offset = s->l1_backup_table[l1_index];
lseek(s->fd, ((int64_t)l2_offset * 512) + (l2_index * sizeof(tmp)), SEEK_SET);
if (write(s->fd, &tmp, sizeof(tmp)) != sizeof(tmp))
if (bdrv_pwrite(s->hd, ((int64_t)l2_offset * 512) + (l2_index * sizeof(tmp)),
&tmp, sizeof(tmp)) != sizeof(tmp))
return 0;
}
if (get_whole_cluster(bs, cluster_offset, offset, allocate) == -1)
return 0;
}
cluster_offset <<= 9;
return cluster_offset;
@ -265,9 +555,9 @@ static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVVmdkState *s = bs->opaque;
int ret, index_in_cluster, n;
int index_in_cluster, n, ret;
uint64_t cluster_offset;
while (nb_sectors > 0) {
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0);
index_in_cluster = sector_num % s->cluster_sectors;
@ -275,11 +565,18 @@ static int vmdk_read(BlockDriverState *bs, int64_t sector_num,
if (n > nb_sectors)
n = nb_sectors;
if (!cluster_offset) {
memset(buf, 0, 512 * n);
// try to read from parent image, if exist
if (s->hd->backing_hd) {
if (!vmdk_is_cid_valid(bs))
return -1;
ret = bdrv_read(s->hd->backing_hd, sector_num, buf, n);
if (ret < 0)
return -1;
} else {
memset(buf, 0, 512 * n);
}
} else {
lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
ret = read(s->fd, buf, n * 512);
if (ret != n * 512)
if(bdrv_pread(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512) != n * 512)
return -1;
}
nb_sectors -= n;
@ -293,8 +590,9 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
BDRVVmdkState *s = bs->opaque;
int ret, index_in_cluster, n;
int index_in_cluster, n;
uint64_t cluster_offset;
static int cid_update = 0;
while (nb_sectors > 0) {
index_in_cluster = sector_num & (s->cluster_sectors - 1);
@ -304,13 +602,17 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num,
cluster_offset = get_cluster_offset(bs, sector_num << 9, 1);
if (!cluster_offset)
return -1;
lseek(s->fd, cluster_offset + index_in_cluster * 512, SEEK_SET);
ret = write(s->fd, buf, n * 512);
if (ret != n * 512)
if (bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512) != n * 512)
return -1;
nb_sectors -= n;
sector_num += n;
buf += n * 512;
// update CID on the first write every time the virtual disk is opened
if (!cid_update) {
vmdk_write_cid(bs, time(NULL));
cid_update++;
}
}
return 0;
}
@ -334,7 +636,7 @@ static int vmdk_create(const char *filename, int64_t total_size,
"# The Disk Data Base \n"
"#DDB\n"
"\n"
"ddb.virtualHWVersion = \"3\"\n"
"ddb.virtualHWVersion = \"4\"\n"
"ddb.geometry.cylinders = \"%lu\"\n"
"ddb.geometry.heads = \"16\"\n"
"ddb.geometry.sectors = \"63\"\n"
@ -343,6 +645,9 @@ static int vmdk_create(const char *filename, int64_t total_size,
const char *real_filename, *temp_str;
/* XXX: add support for backing file */
if (backing_file) {
return vmdk_snapshot_create(filename, backing_file);
}
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
0644);
@ -421,15 +726,18 @@ static int vmdk_create(const char *filename, int64_t total_size,
static void vmdk_close(BlockDriverState *bs)
{
BDRVVmdkState *s = bs->opaque;
qemu_free(s->l1_table);
qemu_free(s->l2_cache);
close(s->fd);
bdrv_delete(s->hd);
// try to close parent image, if exist
vmdk_parent_close(s->hd);
}
static void vmdk_flush(BlockDriverState *bs)
{
BDRVVmdkState *s = bs->opaque;
fsync(s->fd);
bdrv_flush(s->hd);
}
BlockDriver bdrv_vmdk = {