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Divide get_cluster_offset() (Laurent Vivier)

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Divide get_cluster_offset() into get_cluster_offset() and
alloc_cluster_offset().

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@5004 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2008-08-14 18:08:21 +00:00
parent 108534b968
commit 052035244f
1 changed files with 134 additions and 78 deletions
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212
block-qcow2.c
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@ -606,22 +606,77 @@ static uint64_t *l2_allocate(BlockDriverState *bs, int l1_index)
return l2_table;
}
static uint64_t get_cluster_offset(BlockDriverState *bs,
uint64_t offset, int allocate,
int compressed_size,
int n_start, int n_end)
/*
* get_cluster_offset
*
* For a given offset of the disk image, return cluster offset in
* qcow2 file.
*
* Return 1, if the offset is found
* Return 0, otherwise.
*
*/
static uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset)
{
BDRVQcowState *s = bs->opaque;
int l1_index, l2_index;
uint64_t l2_offset, *l2_table, cluster_offset;
/* seek the the l2 offset in the l1 table */
l1_index = offset >> (s->l2_bits + s->cluster_bits);
if (l1_index >= s->l1_size)
return 0;
l2_offset = s->l1_table[l1_index];
/* seek the l2 table of the given l2 offset */
if (!l2_offset)
return 0;
/* load the l2 table in memory */
l2_offset &= ~QCOW_OFLAG_COPIED;
l2_table = l2_load(bs, l2_offset);
if (l2_table == NULL)
return 0;
/* 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]);
return cluster_offset & ~QCOW_OFLAG_COPIED;
}
/*
* 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 compressed_size,
int n_start, int n_end)
{
BDRVQcowState *s = bs->opaque;
int l1_index, l2_index, ret;
uint64_t l2_offset, *l2_table, cluster_offset, tmp;
uint64_t l2_offset, *l2_table, cluster_offset;
/* seek the the l2 offset in the l1 table */
l1_index = offset >> (s->l2_bits + s->cluster_bits);
if (l1_index >= s->l1_size) {
/* outside l1 table is allowed: we grow the table if needed */
if (!allocate)
return 0;
ret = grow_l1_table(bs, l1_index + 1);
if (ret < 0)
return 0;
@ -630,44 +685,30 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
/* seek the l2 table of the given l2 offset */
if (!l2_offset) {
/* the l2 table doesn't exist */
if (!allocate)
if (l2_offset & QCOW_OFLAG_COPIED) {
/* load the l2 table in memory */
l2_offset &= ~QCOW_OFLAG_COPIED;
l2_table = l2_load(bs, l2_offset);
if (l2_table == NULL)
return 0;
/* allocate a new l2 table for this offset */
} else {
if (l2_offset)
free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
l2_table = l2_allocate(bs, l1_index);
if (l2_table == NULL)
return 0;
l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
} else {
/* the l2 table exists */
if (!(l2_offset & QCOW_OFLAG_COPIED) && allocate) {
/* duplicate the l2 table, and free the old table */
free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
l2_table = l2_allocate(bs, l1_index);
if (l2_table == NULL)
return 0;
l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
} else {
/* load the l2 table in memory */
l2_offset &= ~QCOW_OFLAG_COPIED;
l2_table = l2_load(bs, l2_offset);
if (l2_table == NULL)
return 0;
}
}
/* 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]);
if (!cluster_offset) {
/* cluster doesn't exist */
if (!allocate)
return 0;
} else if (!(cluster_offset & QCOW_OFLAG_COPIED)) {
if (!allocate)
return cluster_offset;
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;
@ -678,46 +719,62 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
} else {
free_clusters(bs, cluster_offset, s->cluster_size);
}
} else {
cluster_offset &= ~QCOW_OFLAG_COPIED;
}
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 |= QCOW_OFLAG_COMPRESSED |
((uint64_t)nb_csectors << s->csize_shift);
/* update L2 table */
/* 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;
return cluster_offset;
}
if (allocate == 1) {
/* allocate a new cluster */
cluster_offset = alloc_clusters(bs, s->cluster_size);
/* allocate a new cluster */
/* we must initialize the cluster content which won't be
written */
if ((n_end - n_start) < s->cluster_sectors) {
uint64_t start_sect;
cluster_offset = alloc_clusters(bs, s->cluster_size);
start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
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 (ret < 0)
return 0;
}
tmp = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED);
} else {
int nb_csectors;
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);
/* compressed clusters never have the copied flag */
tmp = cpu_to_be64(cluster_offset);
/* we must initialize the cluster content which won't be
written */
if ((n_end - n_start) < s->cluster_sectors) {
uint64_t start_sect;
start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
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 (ret < 0)
return 0;
}
/* update L2 table */
l2_table[l2_index] = tmp;
l2_table[l2_index] = cpu_to_be64(cluster_offset | QCOW_OFLAG_COPIED);
if (bdrv_pwrite(s->hd,
l2_offset + l2_index * sizeof(tmp), &tmp, sizeof(tmp)) != sizeof(tmp))
l2_offset + l2_index * sizeof(uint64_t),
l2_table + l2_index,
sizeof(uint64_t)) != sizeof(uint64_t))
return 0;
return cluster_offset;
}
@ -728,7 +785,7 @@ static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
int index_in_cluster, n;
uint64_t cluster_offset;
cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
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)
@ -810,7 +867,7 @@ 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, 0, 0, 0, 0);
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)
@ -859,9 +916,9 @@ 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 = get_cluster_offset(bs, sector_num << 9, 1, 0,
index_in_cluster,
index_in_cluster + n);
cluster_offset = alloc_cluster_offset(bs, sector_num << 9, 0,
index_in_cluster,
index_in_cluster + n);
if (!cluster_offset)
return -1;
if (s->crypt_method) {
@ -934,8 +991,7 @@ 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,
0, 0, 0, 0);
acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9);
index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
acb->n = s->cluster_sectors - index_in_cluster;
if (acb->n > acb->nb_sectors)
@ -1044,9 +1100,9 @@ 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 = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
index_in_cluster,
index_in_cluster + acb->n);
cluster_offset = alloc_cluster_offset(bs, acb->sector_num << 9, 0,
index_in_cluster,
index_in_cluster + acb->n);
if (!cluster_offset || (cluster_offset & 511) != 0) {
ret = -EIO;
goto fail;
@ -1306,8 +1362,8 @@ 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 = get_cluster_offset(bs, sector_num << 9, 2,
out_len, 0, 0);
cluster_offset = alloc_cluster_offset(bs, sector_num << 9,
out_len, 0, 0);
cluster_offset &= s->cluster_offset_mask;
if (bdrv_pwrite(s->hd, cluster_offset, out_buf, out_len) != out_len) {
qemu_free(out_buf);