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Extract compressing part from alloc_cluster_offset() (Laurent Vivier)

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Divide alloc_cluster_offset() into alloc_cluster_offset() and
alloc_compressed_cluster_offset().
Common parts are moved to free_any_clusters() and get_cluster_table();

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@5005 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2008-08-14 18:09:32 +00:00
parent 052035244f
commit 52d893ecf9
1 changed files with 126 additions and 47 deletions
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173
block-qcow2.c
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@ -652,26 +652,53 @@ static uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset)
}
/*
* alloc_cluster_offset
* free_any_clusters
*
* For a given offset of the disk image, return cluster offset in
* qcow2 file.
*
* If the offset is not found, allocate a new cluster.
*
* Return the cluster offset if successful,
* Return 0, otherwise.
* free clusters according to its type: compressed or not
*
*/
static uint64_t alloc_cluster_offset(BlockDriverState *bs,
uint64_t offset,
int compressed_size,
int n_start, int n_end)
static void free_any_clusters(BlockDriverState *bs,
uint64_t cluster_offset)
{
BDRVQcowState *s = bs->opaque;
if (cluster_offset == 0)
return;
/* free the cluster */
if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
int nb_csectors;
nb_csectors = ((cluster_offset >> s->csize_shift) &
s->csize_mask) + 1;
free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
nb_csectors * 512);
return;
}
free_clusters(bs, cluster_offset, s->cluster_size);
}
/*
* get_cluster_table
*
* for a given disk offset, load (and allocate if needed)
* the l2 table.
*
* the l2 table offset in the qcow2 file and the cluster index
* in the l2 table are given to the caller.
*
*/
static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
uint64_t **new_l2_table,
uint64_t *new_l2_offset,
int *new_l2_index)
{
BDRVQcowState *s = bs->opaque;
int l1_index, l2_index, ret;
uint64_t l2_offset, *l2_table, cluster_offset;
uint64_t l2_offset, *l2_table;
/* seek the the l2 offset in the l1 table */
@ -703,47 +730,97 @@ static uint64_t alloc_cluster_offset(BlockDriverState *bs,
/* 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]);
*new_l2_table = l2_table;
*new_l2_offset = l2_offset;
*new_l2_index = l2_index;
return 1;
}
/*
* alloc_compressed_cluster_offset
*
* For a given offset of the disk image, return cluster offset in
* qcow2 file.
*
* If the offset is not found, allocate a new compressed cluster.
*
* Return the cluster offset if successful,
* Return 0, otherwise.
*
*/
static uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
uint64_t offset,
int compressed_size)
{
BDRVQcowState *s = bs->opaque;
int l2_index, ret;
uint64_t l2_offset, *l2_table, cluster_offset;
int nb_csectors;
ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
if (ret == 0)
return 0;
cluster_offset = be64_to_cpu(l2_table[l2_index]);
if (cluster_offset & QCOW_OFLAG_COPIED)
return cluster_offset & ~QCOW_OFLAG_COPIED;
if (cluster_offset) {
/* free the cluster */
if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
int nb_csectors;
nb_csectors = ((cluster_offset >> s->csize_shift) &
s->csize_mask) + 1;
free_clusters(bs, (cluster_offset & s->cluster_offset_mask) & ~511,
nb_csectors * 512);
} else {
free_clusters(bs, cluster_offset, s->cluster_size);
}
}
free_any_clusters(bs, cluster_offset);
if (compressed_size) {
int nb_csectors;
cluster_offset = alloc_bytes(bs, compressed_size);
nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
(cluster_offset >> 9);
cluster_offset = alloc_bytes(bs, compressed_size);
nb_csectors = ((cluster_offset + compressed_size - 1) >> 9) -
(cluster_offset >> 9);
cluster_offset |= QCOW_OFLAG_COMPRESSED |
((uint64_t)nb_csectors << s->csize_shift);
cluster_offset |= QCOW_OFLAG_COMPRESSED |
((uint64_t)nb_csectors << s->csize_shift);
/* update L2 table */
/* update L2 table */
/* compressed clusters never have the copied flag */
/* compressed clusters never have the copied flag */
l2_table[l2_index] = cpu_to_be64(cluster_offset);
if (bdrv_pwrite(s->hd,
l2_offset + l2_index * sizeof(uint64_t),
l2_table + l2_index,
sizeof(uint64_t)) != sizeof(uint64_t))
return 0;
l2_table[l2_index] = cpu_to_be64(cluster_offset);
if (bdrv_pwrite(s->hd,
l2_offset + l2_index * sizeof(uint64_t),
l2_table + l2_index,
sizeof(uint64_t)) != sizeof(uint64_t))
return 0;
return cluster_offset;
}
return cluster_offset;
}
/*
* alloc_cluster_offset
*
* For a given offset of the disk image, return cluster offset in
* qcow2 file.
*
* If the offset is not found, allocate a new cluster.
*
* Return the cluster offset if successful,
* Return 0, otherwise.
*
*/
static uint64_t alloc_cluster_offset(BlockDriverState *bs,
uint64_t offset,
int n_start, int n_end)
{
BDRVQcowState *s = bs->opaque;
int l2_index, ret;
uint64_t l2_offset, *l2_table, cluster_offset;
ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index);
if (ret == 0)
return 0;
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);
/* allocate a new cluster */
@ -916,7 +993,7 @@ static int qcow_write(BlockDriverState *bs, int64_t sector_num,
n = s->cluster_sectors - index_in_cluster;
if (n > nb_sectors)
n = nb_sectors;
cluster_offset = alloc_cluster_offset(bs, sector_num << 9, 0,
cluster_offset = alloc_cluster_offset(bs, sector_num << 9,
index_in_cluster,
index_in_cluster + n);
if (!cluster_offset)
@ -1100,7 +1177,7 @@ static void qcow_aio_write_cb(void *opaque, int ret)
acb->n = s->cluster_sectors - index_in_cluster;
if (acb->n > acb->nb_sectors)
acb->n = acb->nb_sectors;
cluster_offset = alloc_cluster_offset(bs, acb->sector_num << 9, 0,
cluster_offset = alloc_cluster_offset(bs, acb->sector_num << 9,
index_in_cluster,
index_in_cluster + acb->n);
if (!cluster_offset || (cluster_offset & 511) != 0) {
@ -1362,8 +1439,10 @@ static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
/* could not compress: write normal cluster */
qcow_write(bs, sector_num, buf, s->cluster_sectors);
} else {
cluster_offset = alloc_cluster_offset(bs, sector_num << 9,
out_len, 0, 0);
cluster_offset = alloc_compressed_cluster_offset(bs, sector_num << 9,
out_len);
if (!cluster_offset)
return -1;
cluster_offset &= s->cluster_offset_mask;
if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
qemu_free(out_buf);