Patchwork [V19,5/8] Make block-cache.c be common interface

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Submitter Robert Wang
Date May 30, 2013, 10 a.m.
Message ID <1369908025-9556-6-git-send-email-wdongxu@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/247534/
State New
Headers show

Comments

Robert Wang - May 30, 2013, 10 a.m.
From: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>

To use block-cache.c be common cache interface, we need to add
some parameter to identify cache's type.

Define a struct named BlockTableType, pass BlockTableType and
table size parameters to block cache initialization function.

v17-v18:
1) move struct to source file.
2) cluster_size->table_size.

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Dongxu Wang <wdongxu@linux.vnet.ibm.com>
---
 block/block-cache.c         | 75 ++++++++++++++++++++++++++-------------------
 block/qcow2-cluster.c       | 30 +++++++++---------
 block/qcow2-refcount.c      | 30 +++++++++---------
 block/qcow2.c               |  7 +++--
 block/qcow2.h               | 24 ++-------------
 include/block/block-cache.h | 55 +++++++++++++++++++++++++++++++++
 trace-events                |  1 +
 7 files changed, 139 insertions(+), 83 deletions(-)
 create mode 100644 include/block/block-cache.h

Patch

diff --git a/block/block-cache.c b/block/block-cache.c
index bc057a8..f5d75d1 100644
--- a/block/block-cache.c
+++ b/block/block-cache.c
@@ -1,4 +1,8 @@ 
 /*
+ * QEMU Block Layer Cache
+ *
+ * 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 <kwolf@redhat.com>
@@ -24,11 +28,11 @@ 
 
 #include "block/block_int.h"
 #include "qemu-common.h"
-#include "qcow2.h"
 #include "trace.h"
+#include "block/block-cache.h"
 
 typedef struct BlockCachedTable {
-    void*   table;
+    void    *table;
     int64_t offset;
     bool    dirty;
     int     cache_hits;
@@ -36,30 +40,34 @@  typedef struct BlockCachedTable {
 } BlockCachedTable;
 
 struct BlockCache {
-    BlockCachedTable*       entries;
-    struct BlockCache*      depends;
-    int                     size;
-    bool                    depends_on_flush;
+    BlockCachedTable    *entries;
+    struct BlockCache   *depends;
+    int                 size;
+    size_t              table_size;
+    BlockTableType      table_type;
+    bool                depends_on_flush;
 };
 
-BlockCache *block_cache_create(BlockDriverState *bs, int num_tables)
+BlockCache *block_cache_create(BlockDriverState *bs, int num_tables,
+                               size_t table_size, BlockTableType type)
 {
-    BDRVQcowState *s = bs->opaque;
     BlockCache *c;
     int i;
 
     c = g_malloc0(sizeof(*c));
     c->size = num_tables;
     c->entries = g_malloc0(sizeof(*c->entries) * num_tables);
+    c->table_type = type;
+    c->table_size = table_size;
 
     for (i = 0; i < c->size; i++) {
-        c->entries[i].table = qemu_blockalign(bs, s->cluster_size);
+        c->entries[i].table = qemu_blockalign(bs, table_size);
     }
 
     return c;
 }
 
-int block_cache_destroy(BlockDriverState* bs, BlockCache *c)
+int block_cache_destroy(BlockDriverState *bs, BlockCache *c)
 {
     int i;
 
@@ -91,15 +99,13 @@  static int block_cache_flush_dependency(BlockDriverState *bs, BlockCache *c)
 
 static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i)
 {
-    BDRVQcowState *s = bs->opaque;
     int ret = 0;
 
     if (!c->entries[i].dirty || !c->entries[i].offset) {
         return 0;
     }
 
-    trace_block_cache_entry_flush(qemu_coroutine_self(),
-                                  c == s->l2_table_cache, i);
+    trace_block_cache_entry_flush(qemu_coroutine_self(), c->table_type, i);
 
     if (c->depends) {
         ret = block_cache_flush_dependency(bs, c);
@@ -114,14 +120,16 @@  static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i)
         return ret;
     }
 
-    if (c == s->refcount_block_cache) {
+    if (c->table_type == BLOCK_TABLE_REF) {
         BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART);
-    } else if (c == s->l2_table_cache) {
+    } else if (c->table_type == BLOCK_TABLE_L2) {
         BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
+    } else if (c->table_type == BLOCK_TABLE_BITMAP) {
+        BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
     }
 
-    ret = bdrv_pwrite(bs->file, c->entries[i].offset, c->entries[i].table,
-        s->cluster_size);
+    ret = bdrv_pwrite(bs->file, c->entries[i].offset,
+                      c->entries[i].table, c->table_size);
     if (ret < 0) {
         return ret;
     }
@@ -133,12 +141,11 @@  static int block_cache_entry_flush(BlockDriverState *bs, BlockCache *c, int i)
 
 int block_cache_flush(BlockDriverState *bs, BlockCache *c)
 {
-    BDRVQcowState *s = bs->opaque;
     int result = 0;
     int ret;
     int i;
 
-    trace_block_cache_flush(qemu_coroutine_self(), c == s->l2_table_cache);
+    trace_block_cache_flush(qemu_coroutine_self(), c->table_type);
 
     for (i = 0; i < c->size; i++) {
         ret = block_cache_entry_flush(bs, c, i);
@@ -157,8 +164,9 @@  int block_cache_flush(BlockDriverState *bs, BlockCache *c)
     return result;
 }
 
-int block_cache_set_dependency(BlockDriverState *bs, BlockCache *c,
-    BlockCache *dependency)
+int block_cache_set_dependency(BlockDriverState *bs,
+                               BlockCache *c,
+                               BlockCache *dependency)
 {
     int ret;
 
@@ -216,13 +224,13 @@  static int block_cache_find_entry_to_replace(BlockCache *c)
 }
 
 static int block_cache_do_get(BlockDriverState *bs, BlockCache *c,
-    uint64_t offset, void **table, bool read_from_disk)
+                              uint64_t offset, void **table,
+                              bool read_from_disk)
 {
-    BDRVQcowState *s = bs->opaque;
     int i;
     int ret;
 
-    trace_block_cache_get(qemu_coroutine_self(), c == s->l2_table_cache,
+    trace_block_cache_get(qemu_coroutine_self(), c->table_type,
                           offset, read_from_disk);
 
     /* Check if the table is already cached */
@@ -235,7 +243,7 @@  static int block_cache_do_get(BlockDriverState *bs, BlockCache *c,
     /* If not, write a table back and replace it */
     i = block_cache_find_entry_to_replace(c);
     trace_block_cache_get_replace_entry(qemu_coroutine_self(),
-                                        c == s->l2_table_cache, i);
+                                        c->table_type, i);
     if (i < 0) {
         return i;
     }
@@ -246,14 +254,17 @@  static int block_cache_do_get(BlockDriverState *bs, BlockCache *c,
     }
 
     trace_block_cache_get_read(qemu_coroutine_self(),
-                               c == s->l2_table_cache, i);
+                               c->table_type, i);
     c->entries[i].offset = 0;
     if (read_from_disk) {
-        if (c == s->l2_table_cache) {
+        if (c->table_type == BLOCK_TABLE_L2) {
             BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
+        } else if (c->table_type == BLOCK_TABLE_BITMAP) {
+            BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
         }
 
-        ret = bdrv_pread(bs->file, offset, c->entries[i].table, s->cluster_size);
+        ret = bdrv_pread(bs->file, offset, c->entries[i].table,
+                         c->table_size);
         if (ret < 0) {
             return ret;
         }
@@ -271,19 +282,19 @@  found:
     *table = c->entries[i].table;
 
     trace_block_cache_get_done(qemu_coroutine_self(),
-                               c == s->l2_table_cache, i);
+                               c->table_type, i);
 
     return 0;
 }
 
 int block_cache_get(BlockDriverState *bs, BlockCache *c, uint64_t offset,
-    void **table)
+                    void **table)
 {
     return block_cache_do_get(bs, c, offset, table, true);
 }
 
-int block_cache_get_empty(BlockDriverState *bs, BlockCache *c, uint64_t offset,
-    void **table)
+int block_cache_get_empty(BlockDriverState *bs, BlockCache *c,
+                          uint64_t offset, void **table)
 {
     return block_cache_do_get(bs, c, offset, table, false);
 }
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index ede64af..7a01c27 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -125,7 +125,8 @@  static int l2_load(BlockDriverState *bs, uint64_t l2_offset,
     BDRVQcowState *s = bs->opaque;
     int ret;
 
-    ret = block_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);
 
     return ret;
 }
@@ -194,7 +195,8 @@  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 = block_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);
     if (ret < 0) {
         return ret;
     }
@@ -211,14 +213,14 @@  static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
         BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
         ret = block_cache_get(bs, s->l2_table_cache,
             old_l2_offset & L1E_OFFSET_MASK,
-            (void**) &old_table);
+            (void **) &old_table);
         if (ret < 0) {
             goto fail;
         }
 
         memcpy(l2_table, old_table, s->cluster_size);
 
-        ret = block_cache_put(bs, s->l2_table_cache, (void**) &old_table);
+        ret = block_cache_put(bs, s->l2_table_cache, (void **) &old_table);
         if (ret < 0) {
             goto fail;
         }
@@ -248,7 +250,7 @@  static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
 
 fail:
     trace_qcow2_l2_allocate_done(bs, l1_index, ret);
-    block_cache_put(bs, s->l2_table_cache, (void**) table);
+    block_cache_put(bs, s->l2_table_cache, (void **) table);
     s->l1_table[l1_index] = old_l2_offset;
     return ret;
 }
@@ -484,7 +486,7 @@  int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
         abort();
     }
 
-    block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
 
     nb_available = (c * s->cluster_sectors);
 
@@ -594,13 +596,13 @@  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) {
-        block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
         return 0;
     }
 
     cluster_offset = qcow2_alloc_bytes(bs, compressed_size);
     if (cluster_offset < 0) {
-        block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
         return 0;
     }
 
@@ -617,7 +619,7 @@  uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
     BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
     block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
     l2_table[l2_index] = cpu_to_be64(cluster_offset);
-    ret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     if (ret < 0) {
         return 0;
     }
@@ -707,7 +709,7 @@  int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
      }
 
 
-    ret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     if (ret < 0) {
         goto err;
     }
@@ -916,7 +918,7 @@  static int handle_copied(BlockDriverState *bs, uint64_t guest_offset,
 
     /* Cleanup */
 out:
-    pret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    pret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     if (pret < 0) {
         return pret;
     }
@@ -1044,7 +1046,7 @@  static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
      * wrong with our code. */
     assert(nb_clusters > 0);
 
-    ret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     if (ret < 0) {
         return ret;
     }
@@ -1342,7 +1344,7 @@  static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
         qcow2_free_any_clusters(bs, old_offset, 1);
     }
 
-    ret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     if (ret < 0) {
         return ret;
     }
@@ -1421,7 +1423,7 @@  static int zero_single_l2(BlockDriverState *bs, uint64_t offset,
         }
     }
 
-    ret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+    ret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     if (ret < 0) {
         return ret;
     }
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 332af27..c7427e8 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -99,7 +99,7 @@  static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
         return 0;
 
     ret = block_cache_get(bs, s->refcount_block_cache, refcount_block_offset,
-        (void**) &refcount_block);
+        (void **) &refcount_block);
     if (ret < 0) {
         return ret;
     }
@@ -109,7 +109,7 @@  static int get_refcount(BlockDriverState *bs, int64_t cluster_index)
     refcount = be16_to_cpu(refcount_block[block_index]);
 
     ret = block_cache_put(bs, s->refcount_block_cache,
-        (void**) &refcount_block);
+        (void **) &refcount_block);
     if (ret < 0) {
         return ret;
     }
@@ -172,7 +172,7 @@  static int alloc_refcount_block(BlockDriverState *bs,
         /* If it's already there, we're done */
         if (refcount_block_offset) {
              return load_refcount_block(bs, refcount_block_offset,
-                 (void**) refcount_block);
+                 (void **) refcount_block);
         }
     }
 
@@ -221,7 +221,7 @@  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 = block_cache_get_empty(bs, s->refcount_block_cache, new_block,
-            (void**) refcount_block);
+            (void **) refcount_block);
         if (ret < 0) {
             goto fail_block;
         }
@@ -248,7 +248,7 @@  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 = block_cache_get_empty(bs, s->refcount_block_cache, new_block,
-            (void**) refcount_block);
+            (void **) refcount_block);
         if (ret < 0) {
             goto fail_block;
         }
@@ -279,7 +279,8 @@  static int alloc_refcount_block(BlockDriverState *bs,
         return 0;
     }
 
-    ret = block_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
+    ret = block_cache_put(bs, s->refcount_block_cache,
+                          (void **) refcount_block);
     if (ret < 0) {
         goto fail_block;
     }
@@ -402,7 +403,7 @@  static int alloc_refcount_block(BlockDriverState *bs,
     qcow2_free_clusters(bs, old_table_offset, old_table_size * sizeof(uint64_t));
     s->free_cluster_index = old_free_cluster_index;
 
-    ret = load_refcount_block(bs, new_block, (void**) refcount_block);
+    ret = load_refcount_block(bs, new_block, (void **) refcount_block);
     if (ret < 0) {
         return ret;
     }
@@ -413,7 +414,7 @@  fail_table:
     g_free(new_table);
 fail_block:
     if (*refcount_block != NULL) {
-        block_cache_put(bs, s->refcount_block_cache, (void**) refcount_block);
+        block_cache_put(bs, s->refcount_block_cache, (void **) refcount_block);
     }
     return ret;
 }
@@ -457,7 +458,7 @@  static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs,
         if (table_index != old_table_index) {
             if (refcount_block) {
                 ret = block_cache_put(bs, s->refcount_block_cache,
-                    (void**) &refcount_block);
+                    (void **) &refcount_block);
                 if (ret < 0) {
                     goto fail;
                 }
@@ -494,7 +495,7 @@  fail:
     if (refcount_block) {
         int wret;
         wret = block_cache_put(bs, s->refcount_block_cache,
-            (void**) &refcount_block);
+            (void **) &refcount_block);
         if (wret < 0) {
             return ret < 0 ? ret : wret;
         }
@@ -768,7 +769,7 @@  int qcow2_update_snapshot_refcount(BlockDriverState *bs,
             l2_offset &= L1E_OFFSET_MASK;
 
             ret = block_cache_get(bs, s->l2_table_cache, l2_offset,
-                (void**) &l2_table);
+                (void **) &l2_table);
             if (ret < 0) {
                 goto fail;
             }
@@ -815,12 +816,13 @@  int qcow2_update_snapshot_refcount(BlockDriverState *bs,
                                 s->refcount_block_cache);
                         }
                         l2_table[j] = cpu_to_be64(offset);
-                        block_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+                        block_cache_entry_mark_dirty(s->l2_table_cache,
+                                                     l2_table);
                     }
                 }
             }
 
-            ret = block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+            ret = block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
             if (ret < 0) {
                 goto fail;
             }
@@ -847,7 +849,7 @@  int qcow2_update_snapshot_refcount(BlockDriverState *bs,
     ret = bdrv_flush(bs);
 fail:
     if (l2_table) {
-        block_cache_put(bs, s->l2_table_cache, (void**) &l2_table);
+        block_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
     }
 
     /* Update L1 only if it isn't deleted anyway (addend = -1) */
diff --git a/block/qcow2.c b/block/qcow2.c
index c3340ad..cec1c26 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -454,8 +454,11 @@  static int qcow2_open(BlockDriverState *bs, QDict *options, int flags)
     }
 
     /* alloc L2 table/refcount block cache */
-    s->l2_table_cache = block_cache_create(bs, L2_CACHE_SIZE);
-    s->refcount_block_cache = block_cache_create(bs, REFCOUNT_CACHE_SIZE);
+    s->l2_table_cache = block_cache_create(bs, L2_CACHE_SIZE,
+                                           s->cluster_size, BLOCK_TABLE_L2);
+    s->refcount_block_cache = block_cache_create(bs, REFCOUNT_CACHE_SIZE,
+                                                 s->cluster_size,
+                                                 BLOCK_TABLE_REF);
 
     s->cluster_cache = g_malloc(s->cluster_size);
     /* one more sector for decompressed data alignment */
diff --git a/block/qcow2.h b/block/qcow2.h
index 6e63217..7494814 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -27,6 +27,7 @@ 
 
 #include "qemu/aes.h"
 #include "block/coroutine.h"
+#include "block/block-cache.h"
 
 //#define DEBUG_ALLOC
 //#define DEBUG_ALLOC2
@@ -97,9 +98,6 @@  typedef struct QCowSnapshot {
     uint64_t vm_clock_nsec;
 } QCowSnapshot;
 
-struct BlockCache;
-typedef struct BlockCache BlockCache;
-
 typedef struct Qcow2UnknownHeaderExtension {
     uint32_t magic;
     uint32_t len;
@@ -149,8 +147,8 @@  typedef struct BDRVQcowState {
     uint64_t l1_table_offset;
     uint64_t *l1_table;
 
-    BlockCache* l2_table_cache;
-    BlockCache* refcount_block_cache;
+    BlockCache  *l2_table_cache;
+    BlockCache  *refcount_block_cache;
 
     uint8_t *cluster_cache;
     uint8_t *cluster_data;
@@ -392,20 +390,4 @@  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 */
-BlockCache *block_cache_create(BlockDriverState *bs, int num_tables);
-int block_cache_destroy(BlockDriverState* bs, BlockCache *c);
-
-void block_cache_entry_mark_dirty(BlockCache *c, void *table);
-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);
-
 #endif
diff --git a/include/block/block-cache.h b/include/block/block-cache.h
new file mode 100644
index 0000000..1992765
--- /dev/null
+++ b/include/block/block-cache.h
@@ -0,0 +1,55 @@ 
+/*
+ * QEMU Block Layer Cache
+ *
+ * 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 <kwolf@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,
+    BLOCK_TABLE_BITMAP,
+} BlockTableType;
+
+struct BlockCache;
+typedef struct BlockCache BlockCache;
+
+BlockCache *block_cache_create(BlockDriverState *bs, int num_tables,
+                               size_t table_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);
+#endif /* BLOCK_CACHE_H */
diff --git a/trace-events b/trace-events
index b7edcc9..b701e01 100644
--- a/trace-events
+++ b/trace-events
@@ -503,6 +503,7 @@  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"
 
+# 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"