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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2008-08-14 18:09:32 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2008-08-14 18:09:32 +0000
commit52d893ecf98a43d17f9b65c5a22a130ecacd9bf1 (patch)
tree008f610c31e9d75ada44284908f431f19478a24c /block-qcow2.c
parent052035244f66acfa532b730b1444c4b7e8a4f302 (diff)
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Extract compressing part from alloc_cluster_offset() (Laurent Vivier)
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
Diffstat (limited to 'block-qcow2.c')
-rw-r--r--block-qcow2.c169
1 files changed, 124 insertions, 45 deletions
diff --git a/block-qcow2.c b/block-qcow2.c
index 1eca17b..b05fd14 100644
--- a/block-qcow2.c
+++ b/block-qcow2.c
@@ -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.
+ * free clusters according to its type: compressed or not
*
- * If the offset is not found, allocate a new cluster.
+ */
+
+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
*
- * Return the cluster offset if successful,
- * Return 0, otherwise.
+ * 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 uint64_t alloc_cluster_offset(BlockDriverState *bs,
- uint64_t offset,
- int compressed_size,
- int n_start, int n_end)
+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);