[Qemu-devel] [PATCH 04/17] qcow2: Dirty Bitmaps Ext: structs and consts

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

Add data structures and constraints accordingly to docs/specs/qcow2.txt

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/Makefile.objs        |  2 +-
 block/qcow2-dirty-bitmap.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 block/qcow2.h              | 28 ++++++++++++++++++++++++++++
 3 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 block/qcow2-dirty-bitmap.c

diff --git a/block/Makefile.objs b/block/Makefile.objs
index 58ef2ef..c6e1f4b 100644
--- a/block/Makefile.objs
+++ b/block/Makefile.objs
@@ -1,5 +1,5 @@
 block-obj-y += raw_bsd.o qcow.o vdi.o vmdk.o cloop.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 qcow2-cache.o qcow2-dirty-bitmap.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-$(CONFIG_VHDX) += vhdx.o vhdx-endian.o vhdx-log.o
diff --git a/block/qcow2-dirty-bitmap.c b/block/qcow2-dirty-bitmap.c
new file mode 100644
index 0000000..fd4e0ef
--- /dev/null
+++ b/block/qcow2-dirty-bitmap.c
@@ -0,0 +1,42 @@
+/*
+ * Dirty bitmaps for the QCOW version 2 format
+ *
+ * Copyright (c) 2014-2015 Vladimir Sementsov-Ogievskiy
+ *
+ * This file is derived from qcow2-snapshot.c, original copyright:
+ * Copyright (c) 2004-2006 Fabrice Bellard
+ *
+ * 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.
+ */
+
+/* NOTICE: DBM here means Dirty Bitmap and used as a namespace for _internal_
+ * constants. Please do not use this _internal_ abbreviation for other needs
+ * and/or outside of this file. */
+
+/* Dirty Bitmap Directory Enrty constraints */
+#define DBM_MAX_TABLE_SIZE 0x8000000
+#define DBM_MAX_PHYS_SIZE 0x20000000 /* 512 mb */
+#define DBM_MAX_GRANULARITY_BITS 63
+#define DBM_MAX_NAME_SIZE 1023
+
+/* Dirty Bitmap Directory Enrty flags */
+#define DBM_RESERVED_FLAGS 0xffffffff
+
+/* bits [0, 8] U [56, 63] are reserved */
+#define DBM_TABLE_ENTRY_RESERVED_MASK 0xff000000000001ff
diff --git a/block/qcow2.h b/block/qcow2.h
index 72e1328..a2a5d4a 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -52,6 +52,10 @@
  * space for snapshot names and IDs */
 #define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS)
 
+/* Dirty Bitmap Header Extension constraints */
+#define QCOW_MAX_DIRTY_BITMAPS 65536
+#define QCOW_MAX_DIRTY_BITMAP_DIRECTORY_SIZE (1024 * QCOW_MAX_DIRTY_BITMAPS)
+
 /* indicate that the refcount of the referenced cluster is exactly one. */
 #define QCOW_OFLAG_COPIED     (1ULL << 63)
 /* indicate that the cluster is compressed (they never have the copied flag) */
@@ -141,6 +145,19 @@ typedef struct QEMU_PACKED QCowSnapshotHeader {
     /* name follows  */
 } QCowSnapshotHeader;
 
+typedef struct QEMU_PACKED QCowDirtyBitmapHeader {
+    /* header is 8 byte aligned */
+    uint64_t dirty_bitmap_table_offset;
+    uint64_t nb_virtual_bits;
+
+    uint32_t dirty_bitmap_table_size;
+    uint32_t granularity_bits;
+
+    uint32_t flags;
+    uint16_t name_size;
+    /* name follows  */
+} QCowDirtyBitmapHeader;
+
 typedef struct QEMU_PACKED QCowSnapshotExtraData {
     uint64_t vm_state_size_large;
     uint64_t disk_size;
@@ -159,6 +176,11 @@ typedef struct QCowSnapshot {
     uint64_t vm_clock_nsec;
 } QCowSnapshot;
 
+typedef struct QCowDirtyBitmap {
+    uint64_t offset;
+    char *name;
+} QCowDirtyBitmap;
+
 struct Qcow2Cache;
 typedef struct Qcow2Cache Qcow2Cache;
 
@@ -221,6 +243,12 @@ typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
 typedef void Qcow2SetRefcountFunc(void *refcount_array,
                                   uint64_t index, uint64_t value);
 
+typedef struct Qcow2DirtyBitmapHeaderExt {
+    uint32_t nb_dirty_bitmaps;
+    uint32_t dirty_bitmap_directory_size;
+    uint64_t dirty_bitmap_directory_offset;
+} QEMU_PACKED Qcow2DirtyBitmapHeaderExt;
+
 typedef struct BDRVQcowState {
     int cluster_bits;
     int cluster_size;
-- 
2.1.4