#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
+#define MIN_CLUSTER_BITS 9
+#define MAX_CLUSTER_BITS 16
+
typedef struct QCowHeader {
uint32_t magic;
uint32_t version;
static int update_cluster_refcount(BlockDriverState *bs,
int64_t cluster_index,
int addend);
-static void update_refcount(BlockDriverState *bs,
+static int update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
int addend);
static int64_t alloc_clusters(BlockDriverState *bs, int64_t size);
if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION)
goto fail;
if (header.size <= 1 ||
- header.cluster_bits < 9 ||
- header.cluster_bits > 16)
+ header.cluster_bits < MIN_CLUSTER_BITS ||
+ header.cluster_bits > MAX_CLUSTER_BITS)
goto fail;
if (header.crypt_method > QCOW_CRYPT_AES)
goto fail;
return 0;
}
-static int qcow_write(BlockDriverState *bs, int64_t sector_num,
- const uint8_t *buf, int nb_sectors)
-{
- BDRVQcowState *s = bs->opaque;
- int ret, index_in_cluster, n;
- uint64_t cluster_offset;
- int n_end;
- QCowL2Meta l2meta;
-
- while (nb_sectors > 0) {
- index_in_cluster = sector_num & (s->cluster_sectors - 1);
- n_end = index_in_cluster + nb_sectors;
- if (s->crypt_method &&
- n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors)
- n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;
- cluster_offset = alloc_cluster_offset(bs, sector_num << 9,
- index_in_cluster,
- n_end, &n, &l2meta);
- if (!cluster_offset)
- return -1;
- if (s->crypt_method) {
- encrypt_sectors(s, sector_num, s->cluster_data, buf, n, 1,
- &s->aes_encrypt_key);
- ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512,
- s->cluster_data, n * 512);
- } else {
- ret = bdrv_pwrite(s->hd, cluster_offset + index_in_cluster * 512, buf, n * 512);
- }
- if (ret != n * 512 || alloc_cluster_link_l2(bs, cluster_offset, &l2meta) < 0) {
- free_any_clusters(bs, cluster_offset, l2meta.nb_clusters);
- return -1;
- }
- nb_sectors -= n;
- sector_num += n;
- buf += n * 512;
- }
- s->cluster_cache_offset = -1; /* disable compressed cache */
- return 0;
-}
-
typedef struct QCowAIOCB {
BlockDriverAIOCB common;
int64_t sector_num;
QCowL2Meta l2meta;
} QCowAIOCB;
+static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
+{
+ QCowAIOCB *acb = (QCowAIOCB *)blockacb;
+ if (acb->hd_aiocb)
+ bdrv_aio_cancel(acb->hd_aiocb);
+ qemu_aio_release(acb);
+}
+
+static AIOPool qcow_aio_pool = {
+ .aiocb_size = sizeof(QCowAIOCB),
+ .cancel = qcow_aio_cancel,
+};
+
static void qcow_aio_read_cb(void *opaque, int ret);
static void qcow_aio_read_bh(void *opaque)
{
{
QCowAIOCB *acb;
- acb = qemu_aio_get(bs, cb, opaque);
+ acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque);
if (!acb)
return NULL;
acb->hd_aiocb = NULL;
return &acb->common;
}
-static void qcow_aio_cancel(BlockDriverAIOCB *blockacb)
-{
- QCowAIOCB *acb = (QCowAIOCB *)blockacb;
- if (acb->hd_aiocb)
- bdrv_aio_cancel(acb->hd_aiocb);
- qemu_aio_release(acb);
-}
-
static void qcow_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
}
}
+static int get_bits_from_size(size_t size)
+{
+ int res = 0;
+
+ if (size == 0) {
+ return -1;
+ }
+
+ while (size != 1) {
+ /* Not a power of two */
+ if (size & 1) {
+ return -1;
+ }
+
+ size >>= 1;
+ res++;
+ }
+
+ return res;
+}
+
static int qcow_create2(const char *filename, int64_t total_size,
const char *backing_file, const char *backing_format,
- int flags)
+ int flags, size_t cluster_size)
{
int fd, header_size, backing_filename_len, l1_size, i, shift, l2_bits;
header.backing_file_size = cpu_to_be32(backing_filename_len);
header_size += backing_filename_len;
}
- s->cluster_bits = 12; /* 4 KB clusters */
+
+ /* Cluster size */
+ s->cluster_bits = get_bits_from_size(cluster_size);
+ if (s->cluster_bits < MIN_CLUSTER_BITS ||
+ s->cluster_bits > MAX_CLUSTER_BITS)
+ {
+ fprintf(stderr, "Cluster size must be a power of two between "
+ "%d and %dk\n",
+ 1 << MIN_CLUSTER_BITS,
+ 1 << (MAX_CLUSTER_BITS - 10));
+ return -EINVAL;
+ }
s->cluster_size = 1 << s->cluster_bits;
+
header.cluster_bits = cpu_to_be32(s->cluster_bits);
header_size = (header_size + 7) & ~7;
if (flags & BLOCK_FLAG_ENCRYPT) {
return 0;
}
-static int qcow_create(const char *filename, int64_t total_size,
- const char *backing_file, int flags)
-{
- return qcow_create2(filename, total_size, backing_file, NULL, flags);
+static int qcow_create(const char *filename, QEMUOptionParameter *options)
+{
+ const char *backing_file = NULL;
+ const char *backing_fmt = NULL;
+ uint64_t sectors = 0;
+ int flags = 0;
+ size_t cluster_size = 4096;
+
+ /* Read out options */
+ while (options && options->name) {
+ if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
+ sectors = options->value.n / 512;
+ } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
+ backing_file = options->value.s;
+ } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FMT)) {
+ backing_fmt = options->value.s;
+ } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
+ flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
+ } else if (!strcmp(options->name, BLOCK_OPT_CLUSTER_SIZE)) {
+ if (options->value.n) {
+ cluster_size = options->value.n;
+ }
+ }
+ options++;
+ }
+
+ return qcow_create2(filename, sectors, backing_file, backing_fmt, flags,
+ cluster_size);
}
static int qcow_make_empty(BlockDriverState *bs)
if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
/* could not compress: write normal cluster */
- qcow_write(bs, sector_num, buf, s->cluster_sectors);
+ bdrv_write(bs, sector_num, buf, s->cluster_sectors);
} else {
cluster_offset = alloc_compressed_cluster_offset(bs, sector_num << 9,
out_len);
return -EIO;
}
-/* addend must be 1 or -1 */
-/* XXX: cache several refcount block clusters ? */
-static int update_cluster_refcount(BlockDriverState *bs,
- int64_t cluster_index,
- int addend)
+
+static int64_t alloc_refcount_block(BlockDriverState *bs, int64_t cluster_index)
{
BDRVQcowState *s = bs->opaque;
int64_t offset, refcount_block_offset;
- int ret, refcount_table_index, block_index, refcount;
+ int ret, refcount_table_index;
uint64_t data64;
+ /* Find L1 index and grow refcount table if needed */
refcount_table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
if (refcount_table_index >= s->refcount_table_size) {
- if (addend < 0)
- return -EINVAL;
ret = grow_refcount_table(bs, refcount_table_index + 1);
if (ret < 0)
return ret;
}
+
+ /* Load or allocate the refcount block */
refcount_block_offset = s->refcount_table[refcount_table_index];
if (!refcount_block_offset) {
- if (addend < 0)
- return -EINVAL;
/* create a new refcount block */
/* Note: we cannot update the refcount now to avoid recursion */
offset = alloc_clusters_noref(bs, s->cluster_size);
return -EIO;
}
}
- /* we can update the count and save it */
- block_index = cluster_index &
- ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
- refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
- refcount += addend;
- if (refcount < 0 || refcount > 0xffff)
- return -EINVAL;
- if (refcount == 0 && cluster_index < s->free_cluster_index) {
- s->free_cluster_index = cluster_index;
+
+ return refcount_block_offset;
+}
+
+/* addend must be 1 or -1 */
+static int update_cluster_refcount(BlockDriverState *bs,
+ int64_t cluster_index,
+ int addend)
+{
+ BDRVQcowState *s = bs->opaque;
+ int ret;
+
+ ret = update_refcount(bs, cluster_index << s->cluster_bits, 1, addend);
+ if (ret < 0) {
+ return ret;
}
- s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
- if (bdrv_pwrite(s->hd,
- refcount_block_offset + (block_index << REFCOUNT_SHIFT),
- &s->refcount_block_cache[block_index], 2) != 2)
- return -EIO;
- return refcount;
+
+ return get_refcount(bs, cluster_index);
}
-static void update_refcount(BlockDriverState *bs,
+/* XXX: cache several refcount block clusters ? */
+static int update_refcount(BlockDriverState *bs,
int64_t offset, int64_t length,
int addend)
{
BDRVQcowState *s = bs->opaque;
int64_t start, last, cluster_offset;
+ int64_t refcount_block_offset = 0;
+ int64_t table_index = -1, old_table_index;
+ int first_index = -1, last_index = -1;
#ifdef DEBUG_ALLOC2
printf("update_refcount: offset=%lld size=%lld addend=%d\n",
offset, length, addend);
#endif
if (length <= 0)
- return;
+ return -EINVAL;
start = offset & ~(s->cluster_size - 1);
last = (offset + length - 1) & ~(s->cluster_size - 1);
for(cluster_offset = start; cluster_offset <= last;
- cluster_offset += s->cluster_size) {
- update_cluster_refcount(bs, cluster_offset >> s->cluster_bits, addend);
+ cluster_offset += s->cluster_size)
+ {
+ int block_index, refcount;
+ int64_t cluster_index = cluster_offset >> s->cluster_bits;
+
+ /* Only write refcount block to disk when we are done with it */
+ old_table_index = table_index;
+ table_index = cluster_index >> (s->cluster_bits - REFCOUNT_SHIFT);
+ if ((old_table_index >= 0) && (table_index != old_table_index)) {
+ size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
+ if (bdrv_pwrite(s->hd,
+ refcount_block_offset + (first_index << REFCOUNT_SHIFT),
+ &s->refcount_block_cache[first_index], size) != size)
+ {
+ return -EIO;
+ }
+
+ first_index = -1;
+ last_index = -1;
+ }
+
+ /* Load the refcount block and allocate it if needed */
+ refcount_block_offset = alloc_refcount_block(bs, cluster_index);
+ if (refcount_block_offset < 0) {
+ return refcount_block_offset;
+ }
+
+ /* we can update the count and save it */
+ block_index = cluster_index &
+ ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
+ if (first_index == -1 || block_index < first_index) {
+ first_index = block_index;
+ }
+ if (block_index > last_index) {
+ last_index = block_index;
+ }
+
+ refcount = be16_to_cpu(s->refcount_block_cache[block_index]);
+ refcount += addend;
+ if (refcount < 0 || refcount > 0xffff)
+ return -EINVAL;
+ if (refcount == 0 && cluster_index < s->free_cluster_index) {
+ s->free_cluster_index = cluster_index;
+ }
+ s->refcount_block_cache[block_index] = cpu_to_be16(refcount);
+ }
+
+ /* Write last changed block to disk */
+ if (refcount_block_offset != 0) {
+ size_t size = (last_index - first_index + 1) << REFCOUNT_SHIFT;
+ if (bdrv_pwrite(s->hd,
+ refcount_block_offset + (first_index << REFCOUNT_SHIFT),
+ &s->refcount_block_cache[first_index], size) != size)
+ {
+ return -EIO;
+ }
}
+
+ return 0;
}
/*
return ret;
}
+static QEMUOptionParameter qcow_create_options[] = {
+ {
+ .name = BLOCK_OPT_SIZE,
+ .type = OPT_SIZE,
+ .help = "Virtual disk size"
+ },
+ {
+ .name = BLOCK_OPT_BACKING_FILE,
+ .type = OPT_STRING,
+ .help = "File name of a base image"
+ },
+ {
+ .name = BLOCK_OPT_BACKING_FMT,
+ .type = OPT_STRING,
+ .help = "Image format of the base image"
+ },
+ {
+ .name = BLOCK_OPT_ENCRYPT,
+ .type = OPT_FLAG,
+ .help = "Encrypt the image"
+ },
+ {
+ .name = BLOCK_OPT_CLUSTER_SIZE,
+ .type = OPT_SIZE,
+ .help = "qcow2 cluster size"
+ },
+ { NULL }
+};
+
static BlockDriver bdrv_qcow2 = {
.format_name = "qcow2",
.instance_size = sizeof(BDRVQcowState),
.bdrv_aio_readv = qcow_aio_readv,
.bdrv_aio_writev = qcow_aio_writev,
- .bdrv_aio_cancel = qcow_aio_cancel,
- .aiocb_size = sizeof(QCowAIOCB),
.bdrv_write_compressed = qcow_write_compressed,
.bdrv_snapshot_create = qcow_snapshot_create,
.bdrv_put_buffer = qcow_put_buffer,
.bdrv_get_buffer = qcow_get_buffer,
- .bdrv_create2 = qcow_create2,
+ .create_options = qcow_create_options,
.bdrv_check = qcow_check,
};
projects / qemu / blobdiff