[Qemu-devel] [PATCH 02/17] qcow2: Bitmaps extension: 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 | 47 ++++++++++++++++++++++++++++++++++++++++++++++
 block/qcow2.h              | 34 +++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 1 deletion(-)
 create mode 100644 block/qcow2-dirty-bitmap.c

diff --git a/block/Makefile.objs b/block/Makefile.objs
index cdd8655..c4dcf7c 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..2c749ab
--- /dev/null
+++ b/block/qcow2-dirty-bitmap.c
@@ -0,0 +1,47 @@
+/*
+ * 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: BME here means Bitmaps Extension and used as a namespace for
+ * _internal_ constants. Please do not use this _internal_ abbreviation for
+ * other needs and/or outside of this file. */
+
+/* Bitmap directory entry constraints */
+#define BME_MAX_TABLE_SIZE 0x8000000
+#define BME_MAX_PHYS_SIZE 0x20000000 /* 512 mb */
+#define BME_MAX_GRANULARITY_BITS 31
+#define BME_MIN_GRANULARITY_BITS 9
+#define BME_MAX_NAME_SIZE 1023
+
+/* Bitmap directory entry flags */
+#define BME_RESERVED_FLAGS 0xffffffff
+
+/* bits [1, 8] U [56, 63] are reserved */
+#define BME_TABLE_ENTRY_RESERVED_MASK 0xff000000000001fe
+
+typedef enum BitmapType {
+    BT_DIRTY_TRACKING_BITMAP = 1
+} BitmapType;
diff --git a/block/qcow2.h b/block/qcow2.h
index a063a3c..3f7429e 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)
 
+/* Bitmap header extension constraints */
+#define QCOW_MAX_DIRTY_BITMAPS 65535
+#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) */
@@ -142,6 +146,22 @@ typedef struct QEMU_PACKED QCowSnapshotHeader {
     /* name follows  */
 } QCowSnapshotHeader;
 
+/* QCow2BitmapHeader is actually a bitmap directory entry */
+typedef struct QEMU_PACKED QCow2BitmapHeader {
+    /* header is 8 byte aligned */
+    uint64_t bitmap_table_offset;
+
+    uint32_t bitmap_table_size;
+    uint32_t flags;
+
+    uint8_t type;
+    uint8_t granularity_bits;
+    uint16_t name_size;
+    uint32_t extra_data_size;
+    /* extra data follows  */
+    /* name follows  */
+} QCow2BitmapHeader;
+
 typedef struct QEMU_PACKED QCowSnapshotExtraData {
     uint64_t vm_state_size_large;
     uint64_t disk_size;
@@ -160,6 +180,11 @@ typedef struct QCowSnapshot {
     uint64_t vm_clock_nsec;
 } QCowSnapshot;
 
+typedef struct QCow2Bitmap {
+    uint64_t offset;
+    char *name;
+} QCow2Bitmap;
+
 struct Qcow2Cache;
 typedef struct Qcow2Cache Qcow2Cache;
 
@@ -222,6 +247,15 @@ typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
 typedef void Qcow2SetRefcountFunc(void *refcount_array,
                                   uint64_t index, uint64_t value);
 
+/* Be careful, Qcow2BitmapHeaderExt is not an extension of QCow2BitmapHeader, it
+ * is Qcow2 header extension */
+typedef struct Qcow2BitmapHeaderExt {
+    uint32_t nb_bitmaps;
+    uint32_t reserved32;
+    uint64_t bitmap_directory_size;
+    uint64_t bitmap_directory_offset;
+} QEMU_PACKED Qcow2BitmapHeaderExt;
+
 typedef struct BDRVQcow2State {
     int cluster_bits;
     int cluster_size;
-- 
1.8.3.1