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.
> +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?
> 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.
> +
> +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
