From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: qemu-block@nongnu.org
Cc: qemu-devel@nongnu.org, mreitz@redhat.com, kwolf@redhat.com,
vsementsov@virtuozzo.com, den@openvz.org, ktkhai@virtuozzo.com,
eblake@redhat.com, berto@igalia.com
Subject: [PATCH v2 02/10] qcow2: compressed read: simplify cluster descriptor passing
Date: Wed, 5 May 2021 09:59:47 +0300 [thread overview]
Message-ID: <20210505065955.13964-3-vsementsov@virtuozzo.com> (raw)
In-Reply-To: <20210505065955.13964-1-vsementsov@virtuozzo.com>
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>
---
block/qcow2.h | 1 -
block/qcow2-cluster.c | 5 ++---
block/qcow2.c | 12 +++++++-----
3 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/block/qcow2.h b/block/qcow2.h
index 0fe5f74ed3..42a0058ab7 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -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
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index bd0597842f..04735ee439 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -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:
diff --git a/block/qcow2.c b/block/qcow2.c
index 9727ae8fe3..746ae85b89 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -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,
@@ -2177,7 +2177,7 @@ 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;
@@ -4665,7 +4665,7 @@ 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,
@@ -4677,8 +4677,10 @@ 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);
--
2.29.2
next prev parent reply other threads:[~2021-05-05 7:11 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 6:59 [PATCH v2 00/10] qcow2 check: check some reserved bits and subcluster bitmaps Vladimir Sementsov-Ogievskiy
2021-05-05 6:59 ` [PATCH v2 01/10] qcow2-refcount: improve style of check_refcounts_l2() Vladimir Sementsov-Ogievskiy
2021-05-05 6:59 ` Vladimir Sementsov-Ogievskiy [this message]
2021-05-10 15:36 ` [PATCH v2 02/10] qcow2: compressed read: simplify cluster descriptor passing Alberto Garcia
2021-05-05 6:59 ` [PATCH v2 03/10] qcow2: introduce qcow2_parse_compressed_l2_entry() helper Vladimir Sementsov-Ogievskiy
2021-05-05 6:59 ` [PATCH v2 04/10] qcow2-refcount: introduce fix_l2_entry_by_zero() Vladimir Sementsov-Ogievskiy
2021-05-05 6:59 ` [PATCH v2 05/10] qcow2-refcount: fix_l2_entry_by_zero(): also zero L2 entry bitmap Vladimir Sementsov-Ogievskiy
2021-05-05 6:59 ` [PATCH v2 06/10] qcow2-refcount: check_refcounts_l2(): check l2_bitmap Vladimir Sementsov-Ogievskiy
2021-05-11 16:49 ` Kirill Tkhai
2021-05-05 6:59 ` [PATCH v2 07/10] qcow2-refcount: check_refcounts_l2(): check reserved bits Vladimir Sementsov-Ogievskiy
2021-05-11 16:54 ` Kirill Tkhai
2021-05-05 6:59 ` [PATCH v2 08/10] qcow2-refcount: improve style of check_refcounts_l1() Vladimir Sementsov-Ogievskiy
2021-05-05 6:59 ` [PATCH v2 09/10] qcow2-refcount: check_refcounts_l1(): check reserved bits Vladimir Sementsov-Ogievskiy
2021-05-11 16:55 ` Kirill Tkhai
2021-05-05 6:59 ` [PATCH v2 10/10] qcow2-refcount: check_refblocks(): add separate message for reserved Vladimir Sementsov-Ogievskiy
2021-05-11 17:09 ` Kirill Tkhai
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