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qcow2: Finalise interface of handle_alloc() 

The interface works completely on a byte granularity now and duplicated
parameters are removed.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
master
Kevin Wolf 2013-03-26 17:50:03 +01:00 committed by Stefan Hajnoczi
parent 3b8e2e260c
commit c37f4cd71d
2 changed files with 21 additions and 13 deletions
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29
block/qcow2-cluster.c
View File

@ -875,13 +875,9 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
* newly allocated cluster. * newly allocated cluster.
* *
* -errno: in error cases * -errno: in error cases
*
* TODO Get rid of n_start, n_end
* TODO Make *bytes actually behave as specified above
*/ */
static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m, uint64_t *host_offset, uint64_t *bytes, QCowL2Meta **m)
int n_start, int n_end)
{ {
BDRVQcowState *s = bs->opaque; BDRVQcowState *s = bs->opaque;
int l2_index; int l2_index;
@ -901,8 +897,11 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
* Calculate the number of clusters to look for. We stop at L2 table * Calculate the number of clusters to look for. We stop at L2 table
* boundaries to keep things simple. * boundaries to keep things simple.
*/ */
nb_clusters =
size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
l2_index = offset_to_l2_index(s, guest_offset); l2_index = offset_to_l2_index(s, guest_offset);
nb_clusters = MIN(size_to_clusters(s, *bytes), s->l2_size - l2_index); nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
/* Find L2 entry for the first involved cluster */ /* Find L2 entry for the first involved cluster */
ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index); ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index);
@ -954,10 +953,13 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
* newly allocated cluster to the end of the aread that the write * newly allocated cluster to the end of the aread that the write
* request actually writes to (excluding COW at the end) * request actually writes to (excluding COW at the end)
*/ */
int requested_sectors = n_end; int requested_sectors =
(*bytes + offset_into_cluster(s, guest_offset))
>> BDRV_SECTOR_BITS;
int avail_sectors = nb_clusters int avail_sectors = nb_clusters
<< (s->cluster_bits - BDRV_SECTOR_BITS); << (s->cluster_bits - BDRV_SECTOR_BITS);
int alloc_n_start = *host_offset == 0 ? n_start : 0; int alloc_n_start = offset_into_cluster(s, guest_offset)
>> BDRV_SECTOR_BITS;
int nb_sectors = MIN(requested_sectors, avail_sectors); int nb_sectors = MIN(requested_sectors, avail_sectors);
if (*host_offset == 0) { if (*host_offset == 0) {
@ -984,7 +986,9 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
qemu_co_queue_init(&(*m)->dependent_requests); qemu_co_queue_init(&(*m)->dependent_requests);
QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight); QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
*bytes = nb_clusters * s->cluster_size; *bytes = MIN(*bytes, (nb_sectors * BDRV_SECTOR_SIZE)
- offset_into_cluster(s, guest_offset));
assert(*bytes != 0);
} else { } else {
*bytes = 0; *bytes = 0;
return 0; return 0;
@ -1139,10 +1143,9 @@ again:
alloc_n_end = n_end; alloc_n_end = n_end;
} }
cur_bytes = nb_clusters * s->cluster_size; cur_bytes = MIN(cur_bytes, ((alloc_n_end - alloc_n_start) << BDRV_SECTOR_BITS));
ret = handle_alloc(bs, offset, &cluster_offset, &cur_bytes, m, ret = handle_alloc(bs, offset, &cluster_offset, &cur_bytes, m);
alloc_n_start, alloc_n_end);
if (ret < 0) { if (ret < 0) {
return ret; return ret;
} }
@ -1150,7 +1153,7 @@ again:
if (!*host_offset) { if (!*host_offset) {
*host_offset = cluster_offset; *host_offset = cluster_offset;
} }
nb_clusters = size_to_clusters(s, cur_bytes); nb_clusters = size_to_clusters(s, cur_bytes + offset_into_cluster(s, offset));
/* Some cleanup work */ /* Some cleanup work */
done: done:

5
block/qcow2.h
View File

@ -271,6 +271,11 @@ static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset)
return offset & ~(s->cluster_size - 1); return offset & ~(s->cluster_size - 1);
} }
static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset)
{
return offset & (s->cluster_size - 1);
}
static inline int size_to_clusters(BDRVQcowState *s, int64_t size) static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
{ {
return (size + (s->cluster_size - 1)) >> s->cluster_bits; return (size + (s->cluster_size - 1)) >> s->cluster_bits;