[Qemu-devel] [PATCH V12 4/6] rename qcow2-cache.c to block-cache.c

[Dong Xu Wang]

add-cow and qcow2 file format will share the same cache code, so rename
block-cache.c to block-cache.c. And related structure and qcow2 code also
are changed.

Signed-off-by: Dong Xu Wang <address@hidden>
---
 block.h                |    3 +
 block/Makefile.objs    |    3 +-
 block/qcow2-cache.c    |  323 ------------------------------------------------
 block/qcow2-cluster.c  |   66 ++++++----
 block/qcow2-refcount.c |   66 ++++++-----
 block/qcow2.c          |   36 +++---
 block/qcow2.h          |   24 +---
 trace-events           |   13 +-
 8 files changed, 109 insertions(+), 425 deletions(-)
 delete mode 100644 block/qcow2-cache.c

diff --git a/block.h b/block.h
index e5dfcd7..c325661 100644
--- a/block.h
+++ b/block.h
@@ -401,6 +401,9 @@ typedef enum {
     BLKDBG_CLUSTER_ALLOC_BYTES,
     BLKDBG_CLUSTER_FREE,
 
+    BLKDBG_ADD_COW_UPDATE,
+    BLKDBG_ADD_COW_LOAD,
+
     BLKDBG_EVENT_MAX,
 } BlkDebugEvent;
 
diff --git a/block/Makefile.objs b/block/Makefile.objs
index b5754d3..23bdfc8 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -1,7 +1,8 @@
 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 += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o
 block-obj-y += qed-check.o
+block-obj-y += block-cache.o
 block-obj-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o
 block-obj-y += stream.o
 block-obj-$(CONFIG_WIN32) += raw-win32.o
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
deleted file mode 100644
index 2d4322a..0000000
--- a/block/qcow2-cache.c
+++ /dev/null
@@ -1,323 +0,0 @@
-/*
- * L2/refcount table cache for the QCOW2 format
- *
- * Copyright (c) 2010 Kevin Wolf <address@hidden>
- *
- * 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 "qcow2.h"
-#include "trace.h"
-
-typedef struct Qcow2CachedTable {
-    void*   table;
-    int64_t offset;
-    bool    dirty;
-    int     cache_hits;
-    int     ref;
-} Qcow2CachedTable;
-
-struct Qcow2Cache {
-    Qcow2CachedTable*       entries;
-    struct Qcow2Cache*      depends;
-    int                     size;
-    bool                    depends_on_flush;
-};
-
-Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables)
-{
-    BDRVQcowState *s = bs->opaque;
-    Qcow2Cache *c;
-    int i;
-
-    c = g_malloc0(sizeof(*c));
-    c->size = num_tables;
-    c->entries = g_malloc0(sizeof(*c->entries) * num_tables);
-
-    for (i = 0; i < c->size; i++) {
-        c->entries[i].table = qemu_blockalign(bs, s->cluster_size);
-    }
-
-    return c;
-}
-
-int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c)
-{
-    int i;
-
-    for (i = 0; i < c->size; i++) {
-        assert(c->entries[i].ref == 0);
-        qemu_vfree(c->entries[i].table);
-    }
-
-    g_free(c->entries);
-    g_free(c);
-
-    return 0;
-}
-
-static int qcow2_cache_flush_dependency(BlockDriverState *bs, Qcow2Cache *c)
-{
-    int ret;
-
-    ret = qcow2_cache_flush(bs, c->depends);
-    if (ret < 0) {
-        return ret;
-    }
-
-    c->depends = NULL;
-    c->depends_on_flush = false;
-
-    return 0;
-}
-
-static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i)
-{
-    BDRVQcowState *s = bs->opaque;
-    int ret = 0;
-
-    if (!c->entries[i].dirty || !c->entries[i].offset) {
-        return 0;
-    }
-
-    trace_qcow2_cache_entry_flush(qemu_coroutine_self(),
-                                  c == s->l2_table_cache, i);
-
-    if (c->depends) {
-        ret = qcow2_cache_flush_dependency(bs, c);
-    } else if (c->depends_on_flush) {
-        ret = bdrv_flush(bs->file);
-        if (ret >= 0) {
-            c->depends_on_flush = false;
-        }
-    }
-
-    if (ret < 0) {
-        return ret;
-    }
-
-    if (c == s->refcount_block_cache) {
-        BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART);
-    } else if (c == s->l2_table_cache) {
-        BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
-    }
-
-    ret = bdrv_pwrite(bs->file, c->entries[i].offset, c->entries[i].table,
-        s->cluster_size);
-    if (ret < 0) {
-        return ret;
-    }
-
-    c->entries[i].dirty = false;
-
-    return 0;
-}
-
-int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c)
-{
-    BDRVQcowState *s = bs->opaque;
-    int result = 0;
-    int ret;
-    int i;
-
-    trace_qcow2_cache_flush(qemu_coroutine_self(), c == s->l2_table_cache);
-
-    for (i = 0; i < c->size; i++) {
-        ret = qcow2_cache_entry_flush(bs, c, i);
-        if (ret < 0 && result != -ENOSPC) {
-            result = ret;
-        }
-    }
-
-    if (result == 0) {
-        ret = bdrv_flush(bs->file);
-        if (ret < 0) {
-            result = ret;
-        }
-    }
-
-    return result;
-}
-
-int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
-    Qcow2Cache *dependency)
-{
-    int ret;
-
-    if (dependency->depends) {
-        ret = qcow2_cache_flush_dependency(bs, dependency);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
-    if (c->depends && (c->depends != dependency)) {
-        ret = qcow2_cache_flush_dependency(bs, c);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
-    c->depends = dependency;
-    return 0;
-}
-
-void qcow2_cache_depends_on_flush(Qcow2Cache *c)
-{
-    c->depends_on_flush = true;
-}
-
-static int qcow2_cache_find_entry_to_replace(Qcow2Cache *c)
-{
-    int i;
-    int min_count = INT_MAX;
-    int min_index = -1;
-
-
-    for (i = 0; i < c->size; i++) {
-        if (c->entries[i].ref) {
-            continue;
-        }
-
-        if (c->entries[i].cache_hits < min_count) {
-            min_index = i;
-            min_count = c->entries[i].cache_hits;
-        }
-
-        /* Give newer hits priority */
-        /* TODO Check how to optimize the replacement strategy */
-        c->entries[i].cache_hits /= 2;
-    }
-
-    if (min_index == -1) {
-        /* This can't happen in current synchronous code, but leave the check
-         * here as a reminder for whoever starts using AIO with the cache */
-        abort();
-    }
-    return min_index;
-}
-
-static int qcow2_cache_do_get(BlockDriverState *bs, Qcow2Cache *c,
-    uint64_t offset, void **table, bool read_from_disk)
-{
-    BDRVQcowState *s = bs->opaque;
-    int i;
-    int ret;
-
-    trace_qcow2_cache_get(qemu_coroutine_self(), c == s->l2_table_cache,
-                          offset, read_from_disk);
-
-    /* Check if the table is already cached */
-    for (i = 0; i < c->size; i++) {
-        if (c->entries[i].offset == offset) {
-            goto found;
-        }
-    }
-
-    /* If not, write a table back and replace it */
-    i = qcow2_cache_find_entry_to_replace(c);
-    trace_qcow2_cache_get_replace_entry(qemu_coroutine_self(),
-                                        c == s->l2_table_cache, i);
-    if (i < 0) {
-        return i;
-    }
-
-    ret = qcow2_cache_entry_flush(bs, c, i);
-    if (ret < 0) {
-        return ret;
-    }
-
-    trace_qcow2_cache_get_read(qemu_coroutine_self(),
-                               c == s->l2_table_cache, i);
-    c->entries[i].offset = 0;
-    if (read_from_disk) {
-        if (c == s->l2_table_cache) {
-            BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
-        }
-
-        ret = bdrv_pread(bs->file, offset, c->entries[i].table, 
s->cluster_size);
-        if (ret < 0) {
-            return ret;
-        }
-    }
-
-    /* Give the table some hits for the start so that it won't be replaced
-     * immediately. The number 32 is completely arbitrary. */
-    c->entries[i].cache_hits = 32;
-    c->entries[i].offset = offset;
-
-    /* And return the right table */
-found:
-    c->entries[i].cache_hits++;
-    c->entries[i].ref++;
-    *table = c->entries[i].table;
-
-    trace_qcow2_cache_get_done(qemu_coroutine_self(),
-                               c == s->l2_table_cache, i);
-
-    return 0;
-}
-
-int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
-    void **table)
-{
-    return qcow2_cache_do_get(bs, c, offset, table, true);
-}
-
-int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
-    void **table)
-{
-    return qcow2_cache_do_get(bs, c, offset, table, false);
-}
-
-int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *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--;
-    *table = NULL;
-
-    assert(c->entries[i].ref >= 0);
-    return 0;
-}
-
-void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table)
-{
-    int i;
-
-    for (i = 0; i < c->size; i++) {
-        if (c->entries[i].table == table) {
-            goto found;
-        }
-    }
-    abort();
-
-found:
-    c->entries[i].dirty = true;
-}
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index e179211..335dc7a 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -28,6 +28,7 @@
 #include "block_int.h"
 #include "block/qcow2.h"
 #include "trace.h"
+#include "block-cache.h"
 
 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size)
 {
@@ -69,7 +70,8 @@ int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, 
bool exact_size)
         return new_l1_table_offset;
     }
 
-    ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+    ret = block_cache_flush(bs, s->refcount_block_cache,
+        BLOCK_TABLE_REF, s->cluster_size);
     if (ret < 0) {
         goto fail;
     }
@@ -119,7 +121,8 @@ static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
     BDRVQcowState *s = bs->opaque;
     int ret;
 
-    ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset, (void**) l2_table);
+    ret = block_cache_get(bs, s->l2_table_cache, l2_offset,
+        (void **) l2_table, BLOCK_TABLE_L2, s->cluster_size);
 
     return ret;
 }
@@ -180,7 +183,8 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, 
uint64_t **table)
         return l2_offset;
     }
 
-    ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+    ret = block_cache_flush(bs, s->refcount_block_cache,
+        BLOCK_TABLE_REF, s->cluster_size);
     if (ret < 0) {
         goto fail;
     }
@@ -188,7 +192,8 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, 
uint64_t **table)
     /* allocate a new entry in the l2 cache */
 
     trace_qcow2_l2_allocate_get_empty(bs, l1_index);
-    ret = qcow2_cache_get_empty(bs, s->l2_table_cache, l2_offset, (void**) 
table);
+    ret = block_cache_get_empty(bs, s->l2_table_cache, l2_offset,
+        (void **) table, BLOCK_TABLE_L2, s->cluster_size);
     if (ret < 0) {
         return ret;
     }
@@ -203,16 +208,17 @@ static int l2_allocate(BlockDriverState *bs, int 
l1_index, uint64_t **table)
 
         /* if there was an old l2 table, read it from the disk */
         BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
-        ret = qcow2_cache_get(bs, s->l2_table_cache,
+        ret = block_cache_get(bs, s->l2_table_cache,
             old_l2_offset & L1E_OFFSET_MASK,
-            (void**) &old_table);
+            (void **) &old_table, BLOCK_TABLE_L2, s->cluster_size);
         if (ret < 0) {
             goto fail;
         }
 
         memcpy(l2_table, old_table, s->cluster_size);
 
-        ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &old_table);
+        ret = block_cache_put(bs, s->l2_table_cache,
+            (void **) &old_table, BLOCK_TABLE_L2);
         if (ret < 0) {
             goto fail;
         }
@@ -222,8 +228,9 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, 
uint64_t **table)
     BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_WRITE);
 
     trace_qcow2_l2_allocate_write_l2(bs, l1_index);
-    qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
-    ret = qcow2_cache_flush(bs, s->l2_table_cache);
+    block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+    ret = block_cache_flush(bs, s->l2_table_cache,
+        BLOCK_TABLE_L2, s->cluster_size);
     if (ret < 0) {
         goto fail;
     }
@@ -242,7 +249,7 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, 
uint64_t **table)
 
 fail:
     trace_qcow2_l2_allocate_done(bs, l1_index, ret);
-    qcow2_cache_put(bs, s->l2_table_cache, (void**) table);
+    block_cache_put(bs, s->l2_table_cache, (void **) table, BLOCK_TABLE_L2);
     s->l1_table[l1_index] = old_l2_offset;
     return ret;
 }
@@ -475,7 +482,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t 
offset,
         abort();
     }
 
-    qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    block_cache_put(bs, s->l2_table_cache, (void **) &l2_table, 
BLOCK_TABLE_L2);
 
     nb_available = (c * s->cluster_sectors);
 
@@ -584,13 +591,15 @@ uint64_t 
qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
      * allocated. */
     cluster_offset = be64_to_cpu(l2_table[l2_index]);
     if (cluster_offset & L2E_OFFSET_MASK) {
-        qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        block_cache_put(bs, s->l2_table_cache,
+            (void **) &l2_table, BLOCK_TABLE_L2);
         return 0;
     }
 
     cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
     if (cluster_offset < 0) {
-        qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        block_cache_put(bs, s->l2_table_cache,
+            (void **) &l2_table, BLOCK_TABLE_L2);
         return 0;
     }
 
@@ -605,9 +614,10 @@ uint64_t 
qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
     /* compressed clusters never have the copied flag */
 
     BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
-    qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+    block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
     l2_table[l2_index] = cpu_to_be64(cluster_offset);
-    ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache,
+        (void **) &l2_table, BLOCK_TABLE_L2);
     if (ret < 0) {
         return 0;
     }
@@ -659,18 +669,16 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, 
QCowL2Meta *m)
      * handled.
      */
     if (cow) {
-        qcow2_cache_depends_on_flush(s->l2_table_cache);
+        block_cache_depends_on_flush(s->l2_table_cache);
     }
 
-    if (qcow2_need_accurate_refcounts(s)) {
-        qcow2_cache_set_dependency(bs, s->l2_table_cache,
-                                   s->refcount_block_cache);
-    }
+    block_cache_set_dependency(bs, s->l2_table_cache, BLOCK_TABLE_L2,
+        s->refcount_block_cache, s->cluster_size);
     ret = get_cluster_table(bs, m->offset, &l2_table, &l2_index);
     if (ret < 0) {
         goto err;
     }
-    qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+    block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
 
     for (i = 0; i < m->nb_clusters; i++) {
         /* if two concurrent writes happen to the same unallocated cluster
@@ -687,7 +695,8 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, 
QCowL2Meta *m)
      }
 
 
-    ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache,
+        (void **) &l2_table, BLOCK_TABLE_L2);
     if (ret < 0) {
         goto err;
     }
@@ -913,7 +922,8 @@ again:
      * request to complete. If we still had the reference, we could use up the
      * whole cache with sleeping requests.
      */
-    ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache,
+        (void **) &l2_table, BLOCK_TABLE_L2);
     if (ret < 0) {
         return ret;
     }
@@ -1077,14 +1087,15 @@ static int discard_single_l2(BlockDriverState *bs, 
uint64_t offset,
         }
 
         /* First remove L2 entries */
-        qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+        block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
         l2_table[l2_index + i] = cpu_to_be64(0);
 
         /* Then decrease the refcount */
         qcow2_free_any_clusters(bs, old_offset, 1);
     }
 
-    ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache,
+        (void **) &l2_table, BLOCK_TABLE_L2);
     if (ret < 0) {
         return ret;
     }
@@ -1154,7 +1165,7 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t 
offset,
         old_offset = be64_to_cpu(l2_table[l2_index + i]);
 
         /* Update L2 entries */
-        qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+        block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
         if (old_offset & QCOW_OFLAG_COMPRESSED) {
             l2_table[l2_index + i] = cpu_to_be64(QCOW_OFLAG_ZERO);
             qcow2_free_any_clusters(bs, old_offset, 1);
@@ -1163,7 +1174,8 @@ static int zero_single_l2(BlockDriverState *bs, uint64_t 
offset,
         }
     }
 
-    ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache,
+        (void **) &l2_table, BLOCK_TABLE_L2);
     if (ret < 0) {
         return ret;
     }
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 5e3f915..728bfc1 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -25,6 +25,7 @@
 #include "qemu-common.h"
 #include "block_int.h"
 #include "block/qcow2.h"
+#include "block-cache.h"
 
 static int64_t alloc_clusters_noref(BlockDriverState *bs, int64_t size);
 static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
@@ -71,8 +72,8 @@ static int load_refcount_block(BlockDriverState *bs,
     int ret;
 
     BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_LOAD);
-    ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
-        refcount_block);
+    ret = block_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
+        refcount_block, BLOCK_TABLE_REF, s->cluster_size);
 
     return ret;
 }
@@ -98,8 +99,8 @@ static int get_refcount(BlockDriverState *bs, int64_t 
cluster_index)
     if (!refcount_block_offset)
         return 0;
 
-    ret = qcow2_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
-        (void**) &refcount_block);
+    ret = block_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
+        (void **) &refcount_block, BLOCK_TABLE_REF, s->cluster_size);
     if (ret < 0) {
         return ret;
     }
@@ -108,8 +109,8 @@ static int get_refcount(BlockDriverState *bs, int64_t 
cluster_index)
         ((1 << (s->cluster_bits - REFCOUNT_SHIFT)) - 1);
     refcount = be16_to_cpu(refcount_block[block_index]);
 
-    ret = qcow2_cache_put(bs, s->refcount_block_cache,
-        (void**) &refcount_block);
+    ret = block_cache_put(bs, s->refcount_block_cache,
+        (void **) &refcount_block, BLOCK_TABLE_REF);
     if (ret < 0) {
         return ret;
     }
@@ -201,7 +202,8 @@ static int alloc_refcount_block(BlockDriverState *bs,
     *refcount_block = NULL;
 
     /* We write to the refcount table, so we might depend on L2 tables */
-    qcow2_cache_flush(bs, s->l2_table_cache);
+    block_cache_flush(bs, s->l2_table_cache,
+        BLOCK_TABLE_L2, s->cluster_size);
 
     /* Allocate the refcount block itself and mark it as used */
     int64_t new_block = alloc_clusters_noref(bs, s->cluster_size);
@@ -217,8 +219,8 @@ static int alloc_refcount_block(BlockDriverState *bs,
 
     if (in_same_refcount_block(s, new_block, cluster_index << 
s->cluster_bits)) {
         /* Zero the new refcount block before updating it */
-        ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block,
-            (void**) refcount_block);
+        ret = block_cache_get_empty(bs, s->refcount_block_cache, new_block,
+            (void **) refcount_block, BLOCK_TABLE_REF, s->cluster_size);
         if (ret < 0) {
             goto fail_block;
         }
@@ -241,8 +243,8 @@ static int alloc_refcount_block(BlockDriverState *bs,
 
         /* Initialize the new refcount block only after updating its refcount,
          * update_refcount uses the refcount cache itself */
-        ret = qcow2_cache_get_empty(bs, s->refcount_block_cache, new_block,
-            (void**) refcount_block);
+        ret = block_cache_get_empty(bs, s->refcount_block_cache, new_block,
+            (void **) refcount_block, BLOCK_TABLE_REF, s->cluster_size);
         if (ret < 0) {
             goto fail_block;
         }
@@ -252,8 +254,9 @@ static int alloc_refcount_block(BlockDriverState *bs,
 
     /* Now the new refcount block needs to be written to disk */
     BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_ALLOC_WRITE);
-    qcow2_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block);
-    ret = qcow2_cache_flush(bs, s->refcount_block_cache);
+    block_cache_entry_mark_dirty(s->refcount_block_cache, *refcount_block);
+    ret = block_cache_flush(bs, s->refcount_block_cache,
+        BLOCK_TABLE_REF, s->cluster_size);
     if (ret < 0) {
         goto fail_block;
     }
@@ -273,7 +276,8 @@ static int alloc_refcount_block(BlockDriverState *bs,
         return 0;
     }
 
-    ret = qcow2_cache_put(bs, s->refcount_block_cache, (void**) 
refcount_block);
+    ret = block_cache_put(bs, s->refcount_block_cache,
+        (void **) refcount_block, BLOCK_TABLE_REF);
     if (ret < 0) {
         goto fail_block;
     }
@@ -406,7 +410,8 @@ fail_table:
     g_free(new_table);
 fail_block:
     if (*refcount_block != NULL) {
-        qcow2_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
+        block_cache_put(bs, s->refcount_block_cache,
+            (void **) refcount_block, BLOCK_TABLE_REF);
     }
     return ret;
 }
@@ -432,8 +437,8 @@ static int QEMU_WARN_UNUSED_RESULT 
update_refcount(BlockDriverState *bs,
     }
 
     if (addend < 0) {
-        qcow2_cache_set_dependency(bs, s->refcount_block_cache,
-            s->l2_table_cache);
+        block_cache_set_dependency(bs, s->refcount_block_cache, 
BLOCK_TABLE_REF,
+            s->l2_table_cache, s->cluster_size);
     }
 
     start = offset & ~(s->cluster_size - 1);
@@ -449,8 +454,8 @@ static int QEMU_WARN_UNUSED_RESULT 
update_refcount(BlockDriverState *bs,
         /* Load the refcount block and allocate it if needed */
         if (table_index != old_table_index) {
             if (refcount_block) {
-                ret = qcow2_cache_put(bs, s->refcount_block_cache,
-                    (void**) &refcount_block);
+                ret = block_cache_put(bs, s->refcount_block_cache,
+                    (void **) &refcount_block, BLOCK_TABLE_REF);
                 if (ret < 0) {
                     goto fail;
                 }
@@ -463,7 +468,7 @@ static int QEMU_WARN_UNUSED_RESULT 
update_refcount(BlockDriverState *bs,
         }
         old_table_index = table_index;
 
-        qcow2_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block);
+        block_cache_entry_mark_dirty(s->refcount_block_cache, refcount_block);
 
         /* we can update the count and save it */
         block_index = cluster_index &
@@ -486,8 +491,8 @@ fail:
     /* Write last changed block to disk */
     if (refcount_block) {
         int wret;
-        wret = qcow2_cache_put(bs, s->refcount_block_cache,
-            (void**) &refcount_block);
+        wret = block_cache_put(bs, s->refcount_block_cache,
+            (void **) &refcount_block, BLOCK_TABLE_REF);
         if (wret < 0) {
             return ret < 0 ? ret : wret;
         }
@@ -763,8 +768,8 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
             old_l2_offset = l2_offset;
             l2_offset &= L1E_OFFSET_MASK;
 
-            ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset,
-                (void**) &l2_table);
+            ret = block_cache_get(bs, s->l2_table_cache, l2_offset,
+                (void **) &l2_table, BLOCK_TABLE_L2, s->cluster_size);
             if (ret < 0) {
                 goto fail;
             }
@@ -811,16 +816,18 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
                     }
                     if (offset != old_offset) {
                         if (addend > 0) {
-                            qcow2_cache_set_dependency(bs, s->l2_table_cache,
-                                s->refcount_block_cache);
+                            block_cache_set_dependency(bs, s->l2_table_cache,
+                                BLOCK_TABLE_L2, s->refcount_block_cache,
+                                s->cluster_size);
                         }
                         l2_table[j] = cpu_to_be64(offset);
-                        qcow2_cache_entry_mark_dirty(s->l2_table_cache, 
l2_table);
+                        block_cache_entry_mark_dirty(s->l2_table_cache, 
l2_table);
                     }
                 }
             }
 
-            ret = qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+            ret = block_cache_put(bs, s->l2_table_cache,
+                (void **) &l2_table, BLOCK_TABLE_L2);
             if (ret < 0) {
                 goto fail;
             }
@@ -847,7 +854,8 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
     ret = 0;
 fail:
     if (l2_table) {
-        qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        block_cache_put(bs, s->l2_table_cache,
+            (void **) &l2_table, BLOCK_TABLE_L2);
     }
 
     /* Update L1 only if it isn't deleted anyway (addend = -1) */
diff --git a/block/qcow2.c b/block/qcow2.c
index fd5e214..b89d312 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -30,6 +30,7 @@
 #include "qemu-error.h"
 #include "qerror.h"
 #include "trace.h"
+#include "block-cache.h"
 
 /*
   Differences with QCOW:
@@ -415,8 +416,9 @@ static int qcow2_open(BlockDriverState *bs, int flags)
     }
 
     /* alloc L2 table/refcount block cache */
-    s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE);
-    s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE);
+    s->l2_table_cache = block_cache_create(bs, L2_CACHE_SIZE, s->cluster_size);
+    s->refcount_block_cache =
+        block_cache_create(bs, REFCOUNT_CACHE_SIZE, s->cluster_size);
 
     s->cluster_cache = g_malloc(s->cluster_size);
     /* one more sector for decompressed data alignment */
@@ -500,7 +502,7 @@ static int qcow2_open(BlockDriverState *bs, int flags)
     qcow2_refcount_close(bs);
     g_free(s->l1_table);
     if (s->l2_table_cache) {
-        qcow2_cache_destroy(bs, s->l2_table_cache);
+        block_cache_destroy(bs, s->l2_table_cache, BLOCK_TABLE_L2);
     }
     g_free(s->cluster_cache);
     qemu_vfree(s->cluster_data);
@@ -860,13 +862,13 @@ static void qcow2_close(BlockDriverState *bs)
     BDRVQcowState *s = bs->opaque;
     g_free(s->l1_table);
 
-    qcow2_cache_flush(bs, s->l2_table_cache);
-    qcow2_cache_flush(bs, s->refcount_block_cache);
-
+    block_cache_flush(bs, s->l2_table_cache,
+        BLOCK_TABLE_L2, s->cluster_size);
+    block_cache_flush(bs, s->refcount_block_cache,
+        BLOCK_TABLE_REF, s->cluster_size);
     qcow2_mark_clean(bs);
-
-    qcow2_cache_destroy(bs, s->l2_table_cache);
-    qcow2_cache_destroy(bs, s->refcount_block_cache);
+    block_cache_destroy(bs, s->l2_table_cache, BLOCK_TABLE_L2);
+    block_cache_destroy(bs, s->refcount_block_cache, BLOCK_TABLE_REF);
 
     g_free(s->unknown_header_fields);
     cleanup_unknown_header_ext(bs);
@@ -1339,8 +1341,6 @@ static int qcow2_create(const char *filename, 
QEMUOptionParameter *options)
                     options->value.s);
                 return -EINVAL;
             }
-        } else if (!strcmp(options->name, BLOCK_OPT_LAZY_REFCOUNTS)) {
-            flags |= options->value.n ? BLOCK_FLAG_LAZY_REFCOUNTS : 0;
         }
         options++;
     }
@@ -1537,18 +1537,18 @@ static coroutine_fn int 
qcow2_co_flush_to_os(BlockDriverState *bs)
     int ret;
 
     qemu_co_mutex_lock(&s->lock);
-    ret = qcow2_cache_flush(bs, s->l2_table_cache);
+    ret = block_cache_flush(bs, s->l2_table_cache,
+        BLOCK_TABLE_L2, s->cluster_size);
     if (ret < 0) {
         qemu_co_mutex_unlock(&s->lock);
         return ret;
     }
 
-    if (qcow2_need_accurate_refcounts(s)) {
-        ret = qcow2_cache_flush(bs, s->refcount_block_cache);
-        if (ret < 0) {
-            qemu_co_mutex_unlock(&s->lock);
-            return ret;
-        }
+    ret = block_cache_flush(bs, s->refcount_block_cache,
+        BLOCK_TABLE_REF, s->cluster_size);
+    if (ret < 0) {
+        qemu_co_mutex_unlock(&s->lock);
+        return ret;
     }
     qemu_co_mutex_unlock(&s->lock);
 
diff --git a/block/qcow2.h b/block/qcow2.h
index b4eb654..cb6fd7a 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -27,6 +27,7 @@
 
 #include "aes.h"
 #include "qemu-coroutine.h"
+#include "block-cache.h"
 
 //#define DEBUG_ALLOC
 //#define DEBUG_ALLOC2
@@ -94,8 +95,6 @@ typedef struct QCowSnapshot {
     uint64_t vm_clock_nsec;
 } QCowSnapshot;
 
-struct Qcow2Cache;
-typedef struct Qcow2Cache Qcow2Cache;
 
 typedef struct Qcow2UnknownHeaderExtension {
     uint32_t magic;
@@ -146,8 +145,8 @@ typedef struct BDRVQcowState {
     uint64_t l1_table_offset;
     uint64_t *l1_table;
 
-    Qcow2Cache* l2_table_cache;
-    Qcow2Cache* refcount_block_cache;
+    BlockCache *l2_table_cache;
+    BlockCache *refcount_block_cache;
 
     uint8_t *cluster_cache;
     uint8_t *cluster_data;
@@ -316,21 +315,4 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const 
char *snapshot_name);
 
 void qcow2_free_snapshots(BlockDriverState *bs);
 int qcow2_read_snapshots(BlockDriverState *bs);
-
-/* qcow2-cache.c functions */
-Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
-int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
-
-void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
-int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
-int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
-    Qcow2Cache *dependency);
-void qcow2_cache_depends_on_flush(Qcow2Cache *c);
-
-int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
-    void **table);
-int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
-    void **table);
-int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
-
 #endif
diff --git a/trace-events b/trace-events
index 6b12f83..52b6438 100644
--- a/trace-events
+++ b/trace-events
@@ -439,12 +439,13 @@ qcow2_l2_allocate_write_l2(void *bs, int l1_index) "bs %p 
l1_index %d"
 qcow2_l2_allocate_write_l1(void *bs, int l1_index) "bs %p l1_index %d"
 qcow2_l2_allocate_done(void *bs, int l1_index, int ret) "bs %p l1_index %d ret 
%d"
 
-qcow2_cache_get(void *co, int c, uint64_t offset, bool read_from_disk) "co %p 
is_l2_cache %d offset %" PRIx64 " read_from_disk %d"
-qcow2_cache_get_replace_entry(void *co, int c, int i) "co %p is_l2_cache %d 
index %d"
-qcow2_cache_get_read(void *co, int c, int i) "co %p is_l2_cache %d index %d"
-qcow2_cache_get_done(void *co, int c, int i) "co %p is_l2_cache %d index %d"
-qcow2_cache_flush(void *co, int c) "co %p is_l2_cache %d"
-qcow2_cache_entry_flush(void *co, int c, int i) "co %p is_l2_cache %d index %d"
+# block/block-cache.c
+block_cache_get(void *co, int c, uint64_t offset, bool read_from_disk) "co %p 
is_l2_cache %d offset %" PRIx64 " read_from_disk %d"
+block_cache_get_replace_entry(void *co, int c, int i) "co %p is_l2_cache %d 
index %d"
+block_cache_get_read(void *co, int c, int i) "co %p is_l2_cache %d index %d"
+block_cache_get_done(void *co, int c, int i) "co %p is_l2_cache %d index %d"
+block_cache_flush(void *co, int c) "co %p is_l2_cache %d"
+block_cache_entry_flush(void *co, int c, int i) "co %p is_l2_cache %d index %d"
 
 # block/qed-l2-cache.c
 qed_alloc_l2_cache_entry(void *l2_cache, void *entry) "l2_cache %p entry %p"
-- 
1.7.1