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qcow2: Aggregate same type clusters (Laurent Vivier) 

Modify get_cluster_offset(), alloc_cluster_offset() to specify how many clusters
we want.

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5006 c046a42c-6fe2-441c-8c8c-71466251a162
stable-0.10
aliguori 18 years ago
parent
52d893ecf9
commit
095a9c58ce
1 changed files with 181 additions and 53 deletions
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  1. 234
      block-qcow2.c

234
block-qcow2.c
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@ -52,6 +52,8 @@
#define QCOW_CRYPT_NONE 0
#define QCOW_CRYPT_AES 1
#define QCOW_MAX_CRYPT_CLUSTERS 32
/* indicate that the refcount of the referenced cluster is exactly one. */
#define QCOW_OFLAG_COPIED (1LL << 63)
/* indicate that the cluster is compressed (they never have the copied flag) */
@ -263,7 +265,8 @@ static int qcow_open(BlockDriverState *bs, const char *filename, int flags)
if (!s->cluster_cache)
goto fail;
/* one more sector for decompressed data alignment */
s->cluster_data = qemu_malloc(s->cluster_size + 512);
s->cluster_data = qemu_malloc(QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
+ 512);
if (!s->cluster_data)
goto fail;
s->cluster_cache_offset = -1;
@ -612,43 +615,98 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
* For a given offset of the disk image, return cluster offset in
* qcow2 file.
*
* on entry, *num is the number of contiguous clusters we'd like to
* access following offset.
*
* on exit, *num is the number of contiguous clusters we can read.
*
* Return 1, if the offset is found
* Return 0, otherwise.
*
*/
static uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset)
static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t offset, int *num)
{
BDRVQcowState *s = bs->opaque;
int l1_index, l2_index;
uint64_t l2_offset, *l2_table, cluster_offset;
uint64_t l2_offset, *l2_table, cluster_offset, next;
int l1_bits;
int index_in_cluster, nb_available, nb_needed;
index_in_cluster = (offset >> 9) & (s->cluster_sectors - 1);
nb_needed = *num + index_in_cluster;
l1_bits = s->l2_bits + s->cluster_bits;
/* compute how many bytes there are between the offset and
* and the end of the l1 entry
*/
nb_available = (1 << l1_bits) - (offset & ((1 << l1_bits) - 1));
/* compute the number of available sectors */
nb_available = (nb_available >> 9) + index_in_cluster;
cluster_offset = 0;
/* seek the the l2 offset in the l1 table */
l1_index = offset >> (s->l2_bits + s->cluster_bits);
l1_index = offset >> l1_bits;
if (l1_index >= s->l1_size)
return 0;
goto out;
l2_offset = s->l1_table[l1_index];
/* seek the l2 table of the given l2 offset */
if (!l2_offset)
return 0;
goto out;
/* load the l2 table in memory */
l2_offset &= ~QCOW_OFLAG_COPIED;
l2_table = l2_load(bs, l2_offset);
if (l2_table == NULL)
return 0;
goto out;
/* find the cluster offset for the given disk offset */
l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
cluster_offset = be64_to_cpu(l2_table[l2_index]);
nb_available = s->cluster_sectors;
l2_index++;
if (!cluster_offset) {
return cluster_offset & ~QCOW_OFLAG_COPIED;
/* how many empty clusters ? */
while (nb_available < nb_needed && !l2_table[l2_index]) {
l2_index++;
nb_available += s->cluster_sectors;
}
} else {
/* how many allocated clusters ? */
cluster_offset &= ~QCOW_OFLAG_COPIED;
while (nb_available < nb_needed) {
next = be64_to_cpu(l2_table[l2_index]) & ~QCOW_OFLAG_COPIED;
if (next != cluster_offset + (nb_available << 9))
break;
l2_index++;
nb_available += s->cluster_sectors;
}
}
out:
if (nb_available > nb_needed)
nb_available = nb_needed;
*num = nb_available - index_in_cluster;
return cluster_offset;
}
/*
@ -659,13 +717,10 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset)
*/
static void free_any_clusters(BlockDriverState *bs,
uint64_t cluster_offset)
uint64_t cluster_offset, int nb_clusters)
{
BDRVQcowState *s = bs->opaque;
if (cluster_offset == 0)
return;
/* free the cluster */
if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
@ -677,7 +732,9 @@ static void free_any_clusters(BlockDriverState *bs,
return;
}
free_clusters(bs, cluster_offset, s->cluster_size);
free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
return;
}
/*
@ -768,7 +825,8 @@ static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
if (cluster_offset & QCOW_OFLAG_COPIED)
return cluster_offset & ~QCOW_OFLAG_COPIED;
free_any_clusters(bs, cluster_offset);
if (cluster_offset)
free_any_clusters(bs, cluster_offset, 1);
cluster_offset = alloc_bytes(bs, compressed_size);
nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
@ -806,68 +864,136 @@ static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
static uint64_t alloc_cluster_offset(BlockDriverState *bs,
uint64_t offset,
int n_start, int n_end)
int n_start, int n_end,
int *num)
{
BDRVQcowState *s = bs->opaque;
int l2_index, ret;
uint64_t l2_offset, *l2_table, cluster_offset;
int nb_available, nb_clusters, i;
uint64_t start_sect, current;
ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
if (ret == 0)
return 0;
nb_clusters = ((n_end << 9) + s->cluster_size - 1) >>
s->cluster_bits;
if (nb_clusters > s->l2_size - l2_index)
nb_clusters = s->l2_size - l2_index;
cluster_offset = be64_to_cpu(l2_table[l2_index]);
if (cluster_offset & QCOW_OFLAG_COPIED)
return cluster_offset & ~QCOW_OFLAG_COPIED;
free_any_clusters(bs, cluster_offset);
/* We keep all QCOW_OFLAG_COPIED clusters */
if (cluster_offset & QCOW_OFLAG_COPIED) {
for (i = 1; i < nb_clusters; i++) {
current = be64_to_cpu(l2_table[l2_index + i]);
if (cluster_offset + (i << s->cluster_bits) != current)
break;
}
nb_clusters = i;
nb_available = nb_clusters << (s->cluster_bits - 9);
if (nb_available > n_end)
nb_available = n_end;
cluster_offset &= ~QCOW_OFLAG_COPIED;
goto out;
}
/* for the moment, multiple compressed clusters are not managed */
if (cluster_offset & QCOW_OFLAG_COMPRESSED)
nb_clusters = 1;
/* how many empty or how many to free ? */
if (!cluster_offset) {
/* how many free clusters ? */
i = 1;
while (i < nb_clusters &&
l2_table[l2_index + i] == 0) {
i++;
}
nb_clusters = i;
} else {
/* how many contiguous clusters ? */
for (i = 1; i < nb_clusters; i++) {
current = be64_to_cpu(l2_table[l2_index + i]);
if (cluster_offset + (i << s->cluster_bits) != current)
break;
}
nb_clusters = i;
free_any_clusters(bs, cluster_offset, i);
}
/* allocate a new cluster */
cluster_offset = alloc_clusters(bs, s->cluster_size);
cluster_offset = alloc_clusters(bs, nb_clusters * s->cluster_size);
/* we must initialize the cluster content which won't be
written */
if ((n_end - n_start) < s->cluster_sectors) {
uint64_t start_sect;
nb_available = nb_clusters << (s->cluster_bits - 9);
if (nb_available > n_end)
nb_available = n_end;
start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
ret = copy_sectors(bs, start_sect,
cluster_offset, 0, n_start);
/* copy content of unmodified sectors */
start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
if (n_start) {
ret = copy_sectors(bs, start_sect, cluster_offset, 0, n_start);
if (ret < 0)
return 0;
ret = copy_sectors(bs, start_sect,
cluster_offset, n_end, s->cluster_sectors);
}
if (nb_available & (s->cluster_sectors - 1)) {
uint64_t end = nb_available & ~(uint64_t)(s->cluster_sectors - 1);
ret = copy_sectors(bs, start_sect + end,
cluster_offset + (end << 9),
nb_available - end,
s->cluster_sectors);
if (ret < 0)
return 0;
}
/* update L2 table */
l2_table[l2_index] = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED);
for (i = 0; i < nb_clusters; i++)
l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
(i << s->cluster_bits)) |
QCOW_OFLAG_COPIED);
if (bdrv_pwrite(s->hd,
l2_offset + l2_index * sizeof(uint64_t),
l2_table + l2_index,
sizeof(uint64_t)) != sizeof(uint64_t))
nb_clusters * sizeof(uint64_t)) !=
nb_clusters * sizeof(uint64_t))
return 0;
out:
*num = nb_available - n_start;
return cluster_offset;
}
static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int *pnum)
{
BDRVQcowState *s = bs->opaque;
int index_in_cluster, n;
uint64_t cluster_offset;
cluster_offset = get_cluster_offset(bs, sector_num << 9);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
*pnum = n;
*pnum = nb_sectors;
cluster_offset = get_cluster_offset(bs, sector_num << 9, pnum);
return (cluster_offset != 0);
}
@ -944,11 +1070,9 @@ static int qcow_read(BlockDriverState *bs, int64_t sector_num,
uint64_t cluster_offset;
while (nb_sectors > 0) {
cluster_offset = get_cluster_offset(bs, sector_num << 9);
n = nb_sectors;
cluster_offset = get_cluster_offset(bs, sector_num << 9, &n);
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
if (!cluster_offset) {
if (bs->backing_hd) {
/* read from the base image */
@ -987,15 +1111,17 @@ static int qcow_write(BlockDriverState *bs, int64_t sector_num,
BDRVQcowState *s = bs->opaque;
int ret, index_in_cluster, n;
uint64_t cluster_offset;
int n_end;
while (nb_sectors > 0) {
index_in_cluster = sector_num & (s->cluster_sectors - 1);
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
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,
index_in_cluster + n);
n_end, &n);
if (!cluster_offset)
return -1;
if (s->crypt_method) {
@ -1068,11 +1194,9 @@ static void qcow_aio_read_cb(void *opaque, int ret)
}
/* prepare next AIO request */
acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9);
acb->n = acb->nb_sectors;
acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, &acb->n);
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
acb->n = s->cluster_sectors - index_in_cluster;
if (acb->n > acb->nb_sectors)
acb->n = acb->nb_sectors;
if (!acb->cluster_offset) {
if (bs->backing_hd) {
@ -1152,6 +1276,7 @@ static void qcow_aio_write_cb(void *opaque, int ret)
int index_in_cluster;
uint64_t cluster_offset;
const uint8_t *src_buf;
int n_end;
acb->hd_aiocb = NULL;
@ -1174,19 +1299,22 @@ static void qcow_aio_write_cb(void *opaque, int ret)
}
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
acb->n = s->cluster_sectors - index_in_cluster;
if (acb->n > acb->nb_sectors)
acb->n = acb->nb_sectors;
n_end = index_in_cluster + acb->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, acb->sector_num << 9,
index_in_cluster,
index_in_cluster + acb->n);
n_end, &acb->n);
if (!cluster_offset || (cluster_offset & 511) != 0) {
ret = -EIO;
goto fail;
}
if (s->crypt_method) {
if (!acb->cluster_data) {
acb->cluster_data = qemu_mallocz(s->cluster_size);
acb->cluster_data = qemu_mallocz(QCOW_MAX_CRYPT_CLUSTERS *
s->cluster_size);
if (!acb->cluster_data) {
ret = -ENOMEM;
goto fail;

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