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qcow2: compressed read: simplify cluster descriptor passing

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Let's pass the whole L2 entry and not bother with
L2E_COMPRESSED_OFFSET_SIZE_MASK.

It also helps further refactoring that adds generic
qcow2_parse_compressed_l2_entry() helper.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20210914122454.141075-3-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2021-09-14 15:24:46 +03:00 committed by Hanna Reitz
parent 786c22d9c2
commit 9a3978a46b
3 changed files with 9 additions and 9 deletions
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5
block/qcow2-cluster.c
View file

@ -556,8 +556,7 @@ static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,
* offset needs to be aligned to a cluster boundary.
*
* If the cluster is unallocated then *host_offset will be 0.
* If the cluster is compressed then *host_offset will contain the
* complete compressed cluster descriptor.
* If the cluster is compressed then *host_offset will contain the l2 entry.
*
* On entry, *bytes is the maximum number of contiguous bytes starting at
* offset that we are interested in.
@ -660,7 +659,7 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset,
ret = -EIO;
goto fail;
}
*host_offset = l2_entry & L2E_COMPRESSED_OFFSET_SIZE_MASK;
*host_offset = l2_entry;
break;
case QCOW2_SUBCLUSTER_ZERO_PLAIN:
case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:

12
block/qcow2.c
View file

@ -74,7 +74,7 @@ typedef struct {
static int coroutine_fn
qcow2_co_preadv_compressed(BlockDriverState *bs,
uint64_t cluster_descriptor,
uint64_t l2_entry,
uint64_t offset,
uint64_t bytes,
QEMUIOVector *qiov,
@ -2205,7 +2205,7 @@ typedef struct Qcow2AioTask {
BlockDriverState *bs;
QCow2SubclusterType subcluster_type; /* only for read */
uint64_t host_offset; /* or full descriptor in compressed clusters */
uint64_t host_offset; /* or l2_entry for compressed read */
uint64_t offset;
uint64_t bytes;
QEMUIOVector *qiov;
@ -4693,7 +4693,7 @@ qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
static int coroutine_fn
qcow2_co_preadv_compressed(BlockDriverState *bs,
uint64_t cluster_descriptor,
uint64_t l2_entry,
uint64_t offset,
uint64_t bytes,
QEMUIOVector *qiov,
@ -4705,8 +4705,10 @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
uint8_t *buf, *out_buf;
int offset_in_cluster = offset_into_cluster(s, offset);
coffset = cluster_descriptor & s->cluster_offset_mask;
nb_csectors = ((cluster_descriptor >> s->csize_shift) & s->csize_mask) + 1;
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);

1
block/qcow2.h
View file

@ -588,7 +588,6 @@ typedef enum QCow2MetadataOverlap {
#define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
#define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
#define REFT_OFFSET_MASK 0xfffffffffffffe00ULL