On Tue, Dec 11, 2012 at 1:11 AM, Kevin Wolf <kw...@redhat.com> wrote:
> Am 06.12.2012 07:51, schrieb Dong Xu Wang:
>> We will re-use qcow2-cache as block layer common cache code,
>> so change its name and made some changes, define a struct named
>> BlockTableType, pass BlockTableType and table size parameters to
>> block cache initialization function.
>>
>> Signed-off-by: Dong Xu Wang <wdon...@linux.vnet.ibm.com>
>> ---
>> block/Makefile.objs | 3 +-
>> block/block-cache.c | 317
>> +++++++++++++++++++++++++++++++++++++++++++++++
>> block/block-cache.h | 76 +++++++++++
>> block/qcow2-cache.c | 323
>> ------------------------------------------------
>> block/qcow2-cluster.c | 53 ++++----
>> block/qcow2-refcount.c | 66 ++++++-----
>> block/qcow2.c | 21 ++--
>> block/qcow2.h | 24 +---
>> trace-events | 13 +-
>> 9 files changed, 481 insertions(+), 415 deletions(-)
>> create mode 100644 block/block-cache.c
>> create mode 100644 block/block-cache.h
>> delete mode 100644 block/qcow2-cache.c
>>
>> diff --git a/block/Makefile.objs b/block/Makefile.objs
>> index 7f01510..d23c250 100644
>> --- a/block/Makefile.objs
>> +++ b/block/Makefile.objs
>> @@ -1,5 +1,6 @@
>> block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o
>> vvfat.o
>> -block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
>> qcow2-cache.o
>> +block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o
>> +block-obj-y += block-cache.o
>> block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
>> block-obj-y += qed-check.o
>> block-obj-y += parallels.o blkdebug.o blkverify.o
>> diff --git a/block/block-cache.c b/block/block-cache.c
>> new file mode 100644
>> index 0000000..bf5c57c
>> --- /dev/null
>> +++ b/block/block-cache.c
>> @@ -0,0 +1,317 @@
>> +/*
>> + * QEMU Block Layer Cache
>> + *
>> + * Copyright IBM, Corp. 2012
>> + *
>> + * Authors:
>> + * Dong Xu Wang <wdon...@linux.vnet.ibm.com>
>> + *
>> + * This file is based on qcow2-cache.c, see its copyrights below:
>> + *
>> + * L2/refcount table cache for the QCOW2 format
>> + *
>> + * Copyright (c) 2010 Kevin Wolf <kw...@redhat.com>
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> copy
>> + * of this software and associated documentation files (the "Software"), to
>> deal
>> + * in the Software without restriction, including without limitation the
>> rights
>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
>> + * copies of the Software, and to permit persons to whom the Software is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included
>> in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
>> OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
>> FROM,
>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>> + * THE SOFTWARE.
>> + */
>> +
>> +#include "block_int.h"
>> +#include "qemu-common.h"
>> +#include "trace.h"
>> +#include "block-cache.h"
>> +
>> +BlockCache *block_cache_create(BlockDriverState *bs, int num_tables,
>> + size_t cluster_size, BlockTableType type)
>
> cluster_size should probably be called table_size. It just happens that
> qcow2 tables are always one cluster, but it may be different for other
> formats using this implementation in the future.
>
Okay.
>> +int block_cache_put(BlockDriverState *bs, BlockCache *c, void **table)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < c->size; i++) {
>> + if (c->entries[i].table == *table) {
>> + goto found;
>> + }
>> + }
>> + return -ENOENT;
>> +
>> +found:
>> + c->entries[i].ref--;
>> + assert(c->entries[i].ref >= 0);
>> + *table = NULL;
>> + return 0;
>> +}
>
> Why did you swap the assert() and *table = NULL?
>
I will use original code here. I have no reason to swap them..
>> diff --git a/block/block-cache.h b/block/block-cache.h
>> new file mode 100644
>> index 0000000..4efa06e
>> --- /dev/null
>> +++ b/block/block-cache.h
>> @@ -0,0 +1,76 @@
>> +/*
>> + * QEMU Block Layer Cache
>> + *
>> + * Copyright IBM, Corp. 2012
>> + *
>> + * Authors:
>> + * Dong Xu Wang <wdon...@linux.vnet.ibm.com>
>> + *
>> + * This file is based on qcow2-cache.c, see its copyrights below:
>> + *
>> + * L2/refcount table cache for the QCOW2 format
>> + *
>> + * Copyright (c) 2010 Kevin Wolf <kw...@redhat.com>
>> + *
>> + * Permission is hereby granted, free of charge, to any person obtaining a
>> copy
>> + * of this software and associated documentation files (the "Software"), to
>> deal
>> + * in the Software without restriction, including without limitation the
>> rights
>> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
>> + * copies of the Software, and to permit persons to whom the Software is
>> + * furnished to do so, subject to the following conditions:
>> + *
>> + * The above copyright notice and this permission notice shall be included
>> in
>> + * all copies or substantial portions of the Software.
>> + *
>> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
>> OR
>> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
>> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
>> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
>> OTHER
>> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
>> FROM,
>> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
>> + * THE SOFTWARE.
>> + */
>> +
>> +#ifndef BLOCK_CACHE_H
>> +#define BLOCK_CACHE_H
>> +
>> +typedef enum {
>> + BLOCK_TABLE_REF,
>> + BLOCK_TABLE_L2,
>> +} BlockTableType;
>
> I'm not excited about exposing these types, but it's okay for now. We
> can always change the implementation later to be nicer.
>
>> +
>> +typedef struct BlockCachedTable {
>> + void *table;
>> + int64_t offset;
>> + bool dirty;
>> + int cache_hits;
>> + int ref;
>> +} BlockCachedTable;
>> +
>> +struct BlockCache {
>> + BlockCachedTable *entries;
>> + struct BlockCache *depends;
>> + int size;
>> + size_t cluster_size;
>> + BlockTableType table_type;
>> + bool depends_on_flush;
>> +};
>
> Why have these definitions been moved to the header file? They are
> supposed to be private to the implementation.
>
Both qcow2.h:BDRVQcowState and add-cow.c: BDRVAddCowState have a
member typed BlockCache,
such as:
typedef struct BDRVAddCowState {
BlockDriverState *image_hd;
CoMutex lock;
int cluster_size;
BlockCache *bitmap_cache;
uint64_t bitmap_size;
AddCowHeader header;
char backing_fmt[16];
char image_fmt[16];
} BDRVAddCowState;
So I have to move the definitions to the header file, so that both
add-cow.c and qcow2.h can use BlockCache.
Is it Okay?
>> +
>> +struct BlockCache;
>> +typedef struct BlockCache BlockCache;
>> +
>> +BlockCache *block_cache_create(BlockDriverState *bs, int num_tables,
>> + size_t cluster_size, BlockTableType type);
>> +int block_cache_destroy(BlockDriverState *bs, BlockCache *c);
>> +int block_cache_flush(BlockDriverState *bs, BlockCache *c);
>> +int block_cache_set_dependency(BlockDriverState *bs,
>> + BlockCache *c,
>> + BlockCache *dependency);
>> +void block_cache_depends_on_flush(BlockCache *c);
>> +int block_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset,
>> + void **table);
>> +int block_cache_get_empty(BlockDriverState *bs, BlockCache *c,
>> + uint64_t offset, void **table);
>> +int block_cache_put(BlockDriverState *bs, BlockCache *c, void **table);
>> +void block_cache_entry_mark_dirty(BlockCache *c, void *table);
>
> Kevin
>
Thank you Kevin.
