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qcow2: introduce qcow2_parse_compressed_l2_entry() helper

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Add helper to parse compressed l2_entry and use it everywhere instead
of open-coding.

Note, that in most places we move to precise coffset/csize instead of
sector-aligned. Still it should work good enough for updating
refcounts.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20210914122454.141075-4-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-09-14 15:24:47 +03:00 committed by Hanna Reitz
parent 9a3978a46b
commit a6e098462b
4 changed files with 36 additions and 27 deletions
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15
block/qcow2-cluster.c
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@ -2480,3 +2480,18 @@ fail:
g_free(l1_table);
return ret;
}
void qcow2_parse_compressed_l2_entry(BlockDriverState *bs, uint64_t l2_entry,
uint64_t *coffset, int *csize)
{
BDRVQcow2State *s = bs->opaque;
int nb_csectors;
assert(qcow2_get_cluster_type(bs, l2_entry) == QCOW2_CLUSTER_COMPRESSED);
*coffset = l2_entry & s->cluster_offset_mask;
nb_csectors = ((l2_entry >> s->csize_shift) & s->csize_mask) + 1;
*csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE -
(*coffset & (QCOW2_COMPRESSED_SECTOR_SIZE - 1));
}

36
block/qcow2-refcount.c
View File

@ -1177,11 +1177,11 @@ void qcow2_free_any_cluster(BlockDriverState *bs, uint64_t l2_entry,
switch (ctype) {
case QCOW2_CLUSTER_COMPRESSED:
{
int64_t offset = (l2_entry & s->cluster_offset_mask)
& QCOW2_COMPRESSED_SECTOR_MASK;
int size = QCOW2_COMPRESSED_SECTOR_SIZE *
(((l2_entry >> s->csize_shift) & s->csize_mask) + 1);
qcow2_free_clusters(bs, offset, size, type);
uint64_t coffset;
int csize;
qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
qcow2_free_clusters(bs, coffset, csize, type);
}
break;
case QCOW2_CLUSTER_NORMAL:
@ -1247,7 +1247,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
bool l1_allocated = false;
int64_t old_entry, old_l2_offset;
unsigned slice, slice_size2, n_slices;
int i, j, l1_modified = 0, nb_csectors;
int i, j, l1_modified = 0;
int ret;
assert(addend >= -1 && addend <= 1);
@ -1318,14 +1318,14 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
switch (qcow2_get_cluster_type(bs, entry)) {
case QCOW2_CLUSTER_COMPRESSED:
nb_csectors = ((entry >> s->csize_shift) &
s->csize_mask) + 1;
if (addend != 0) {
uint64_t coffset = (entry & s->cluster_offset_mask)
& QCOW2_COMPRESSED_SECTOR_MASK;
uint64_t coffset;
int csize;
qcow2_parse_compressed_l2_entry(bs, entry,
&coffset, &csize);
ret = update_refcount(
bs, coffset,
nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE,
bs, coffset, csize,
abs(addend), addend < 0,
QCOW2_DISCARD_SNAPSHOT);
if (ret < 0) {
@ -1603,7 +1603,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
BDRVQcow2State *s = bs->opaque;
uint64_t l2_entry;
uint64_t next_contiguous_offset = 0;
int i, nb_csectors, ret;
int i, ret;
size_t l2_size_bytes = s->l2_size * l2_entry_size(s);
g_autofree uint64_t *l2_table = g_malloc(l2_size_bytes);
@ -1617,6 +1617,8 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
/* Do the actual checks */
for (i = 0; i < s->l2_size; i++) {
uint64_t coffset;
int csize;
l2_entry = get_l2_entry(s, l2_table, i);
switch (qcow2_get_cluster_type(bs, l2_entry)) {
@ -1638,13 +1640,9 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
}
/* Mark cluster as used */
nb_csectors = ((l2_entry >> s->csize_shift) &
s->csize_mask) + 1;
l2_entry &= s->cluster_offset_mask;
qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
ret = qcow2_inc_refcounts_imrt(
bs, res, refcount_table, refcount_table_size,
l2_entry & QCOW2_COMPRESSED_SECTOR_MASK,
nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE);
bs, res, refcount_table, refcount_table_size, coffset, csize);
if (ret < 0) {
return ret;
}

9
block/qcow2.c
View File

@ -4700,17 +4700,12 @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
size_t qiov_offset)
{
BDRVQcow2State *s = bs->opaque;
int ret = 0, csize, nb_csectors;
int ret = 0, csize;
uint64_t coffset;
uint8_t *buf, *out_buf;
int offset_in_cluster = offset_into_cluster(s, offset);
assert(qcow2_get_cluster_type(bs, l2_entry) == QCOW2_CLUSTER_COMPRESSED);
coffset = l2_entry & s->cluster_offset_mask;
nb_csectors = ((l2_entry >> s->csize_shift) & s->csize_mask) + 1;
csize = nb_csectors * QCOW2_COMPRESSED_SECTOR_SIZE -
(coffset & ~QCOW2_COMPRESSED_SECTOR_MASK);
qcow2_parse_compressed_l2_entry(bs, l2_entry, &coffset, &csize);
buf = g_try_malloc(csize);
if (!buf) {

3
block/qcow2.h
View File

@ -110,7 +110,6 @@
/* Defined in the qcow2 spec (compressed cluster descriptor) */
#define QCOW2_COMPRESSED_SECTOR_SIZE 512U
#define QCOW2_COMPRESSED_SECTOR_MASK (~(QCOW2_COMPRESSED_SECTOR_SIZE - 1ULL))
/* Must be at least 2 to cover COW */
#define MIN_L2_CACHE_SIZE 2 /* cache entries */
@ -913,6 +912,8 @@ int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
uint64_t offset,
int compressed_size,
uint64_t *host_offset);
void qcow2_parse_compressed_l2_entry(BlockDriverState *bs, uint64_t l2_entry,
uint64_t *coffset, int *csize);
int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);