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qcow2: Update zero_single_l2() to support L2 slices

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zero_single_l2() limits the number of clusters to be zeroed to the
amount that fits inside an L2 table. Since we'll be loading L2 slices
instead of full tables we need to update that limit. The function is
renamed to zero_in_l2_slice() for clarity.

Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: ebc16e7e79fa6969d8975ef487d679794de4fbcc.1517840877.git.berto@igalia.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Alberto Garcia 2018-02-05 16:33:25 +02:00 committed by Max Reitz
parent 21ab3add9c
commit a9a9f8f0b6
1 changed files with 14 additions and 14 deletions
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28
block/qcow2-cluster.c
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@ -1752,33 +1752,33 @@ fail:
/*
* This zeroes as many clusters of nb_clusters as possible at once (i.e.
* all clusters in the same L2 table) and returns the number of zeroed
* all clusters in the same L2 slice) and returns the number of zeroed
* clusters.
*/
static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
uint64_t nb_clusters, int flags)
static int zero_in_l2_slice(BlockDriverState *bs, uint64_t offset,
uint64_t nb_clusters, int flags)
{
BDRVQcow2State *s = bs->opaque;
uint64_t *l2_table;
uint64_t *l2_slice;
int l2_index;
int ret;
int i;
bool unmap = !!(flags & BDRV_REQ_MAY_UNMAP);
ret = get_cluster_table(bs, offset, &l2_table, &l2_index);
ret = get_cluster_table(bs, offset, &l2_slice, &l2_index);
if (ret < 0) {
return ret;
}
/* Limit nb_clusters to one L2 table */
nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
/* Limit nb_clusters to one L2 slice */
nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
assert(nb_clusters <= INT_MAX);
for (i = 0; i < nb_clusters; i++) {
uint64_t old_offset;
QCow2ClusterType cluster_type;
old_offset = be64_to_cpu(l2_table[l2_index + i]);
old_offset = be64_to_cpu(l2_slice[l2_index + i]);
/*
* Minimize L2 changes if the cluster already reads back as
@ -1790,16 +1790,16 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
continue;
}
qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
if (cluster_type == QCOW2_CLUSTER_COMPRESSED || unmap) {
l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
l2_slice[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
qcow2_free_any_clusters(bs, old_offset, 1, QCOW2_DISCARD_REQUEST);
} else {
l2_table[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO);
l2_slice[l2_index + i] |= cpu_to_be64(QCOW_OFLAG_ZERO);
}
}
qcow2_cache_put(s->l2_table_cache, (void **) &l2_table);
qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
return nb_clusters;
}
@ -1823,13 +1823,13 @@ int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
return -ENOTSUP;
}
/* Each L2 table is handled by its own loop iteration */
/* Each L2 slice is handled by its own loop iteration */
nb_clusters = size_to_clusters(s, bytes);
s->cache_discards = true;
while (nb_clusters > 0) {
cleared = zero_single_l2(bs, offset, nb_clusters, flags);
cleared = zero_in_l2_slice(bs, offset, nb_clusters, flags);
if (cleared < 0) {
ret = cleared;
goto fail;