[PATCH v4 11/21] parallels: Add dirty bitmaps saving

[Alexander Ivanov <alexander.ivanov@virtuozzo.com>]

Now dirty bitmaps can be loaded but there is no their saving. Add code for
dirty bitmap storage.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
---
 block/parallels-ext.c | 168 ++++++++++++++++++++++++++++++++++++++++++
 block/parallels.c     |  16 +++-
 block/parallels.h     |   5 ++
 3 files changed, 187 insertions(+), 2 deletions(-)

diff --git a/block/parallels-ext.c b/block/parallels-ext.c
index b4e14c88f2..c83d1ea393 100644
--- a/block/parallels-ext.c
+++ b/block/parallels-ext.c
@@ -24,6 +24,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/error-report.h"
 #include "qapi/error.h"
 #include "block/block-io.h"
 #include "block/block_int.h"
@@ -300,3 +301,170 @@ out:
 
     return ret;
 }
+
+static void GRAPH_RDLOCK parallels_save_bitmap(BlockDriverState *bs,
+                                               BdrvDirtyBitmap *bitmap,
+                                               uint8_t **buf, int *buf_size)
+{
+    BDRVParallelsState *s = bs->opaque;
+    ParallelsFeatureHeader *fh;
+    ParallelsDirtyBitmapFeature *bh;
+    uint64_t *l1_table, l1_size, granularity, limit;
+    int64_t bm_size, ser_size, offset, buf_used;
+    int64_t alloc_size = 1;
+    const char *name;
+    uint8_t *bm_buf;
+    QemuUUID uuid;
+    int ret = 0;
+
+    if (!bdrv_dirty_bitmap_get_persistence(bitmap) ||
+        bdrv_dirty_bitmap_inconsistent(bitmap)) {
+        return;
+    }
+
+    bm_size = bdrv_dirty_bitmap_size(bitmap);
+    granularity = bdrv_dirty_bitmap_granularity(bitmap);
+    limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap);
+    ser_size = bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size);
+    l1_size = DIV_ROUND_UP(ser_size, s->cluster_size);
+
+    buf_used = l1_size * 8 + sizeof(*fh) + sizeof(*bh);
+    /* Check if there is enough space for the final section */
+    if (*buf_size - buf_used < sizeof(*fh)) {
+        return;
+    }
+
+    name = bdrv_dirty_bitmap_name(bitmap);
+    ret = qemu_uuid_parse(name, &uuid);
+    if (ret < 0) {
+        error_report("Can't save dirty bitmap: ID parsing error: '%s'", name);
+        return;
+    }
+
+    fh = (ParallelsFeatureHeader *)*buf;
+    bh = (ParallelsDirtyBitmapFeature *)(*buf + sizeof(*fh));
+    l1_table = (uint64_t *)((uint8_t *)bh + sizeof(*bh));
+
+    fh->magic = cpu_to_le64(PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC);
+    fh->data_size = cpu_to_le32(l1_size * 8 + sizeof(*bh));
+
+    bh->l1_size = cpu_to_le32(l1_size);
+    bh->size = cpu_to_le64(bm_size >> BDRV_SECTOR_BITS);
+    bh->granularity = cpu_to_le32(granularity >> BDRV_SECTOR_BITS);
+    memcpy(bh->id, &uuid, sizeof(uuid));
+
+    bm_buf = qemu_blockalign(bs, s->cluster_size);
+
+    offset = 0;
+    while ((offset = bdrv_dirty_bitmap_next_dirty(bitmap, offset, bm_size)) >= 0) {
+        uint64_t idx = offset / limit;
+        int64_t cluster_off, end, write_size;
+
+        offset = QEMU_ALIGN_DOWN(offset, limit);
+        end = MIN(bm_size, offset + limit);
+        write_size = bdrv_dirty_bitmap_serialization_size(bitmap, offset,
+                                                          end - offset);
+        assert(write_size <= s->cluster_size);
+
+        bdrv_dirty_bitmap_serialize_part(bitmap, bm_buf, offset, end - offset);
+        if (write_size < s->cluster_size) {
+            memset(bm_buf + write_size, 0, s->cluster_size - write_size);
+        }
+
+        cluster_off = parallels_allocate_host_clusters(bs, &alloc_size);
+        if (cluster_off <= 0) {
+            goto end;
+        }
+
+        ret = bdrv_pwrite(bs->file, cluster_off, s->cluster_size, bm_buf, 0);
+        if (ret < 0) {
+            memset(&fh->magic, 0, sizeof(fh->magic));
+            parallels_mark_unused(bs, s->used_bmap, s->used_bmap_size,
+                                  cluster_off, 1);
+            goto end;
+        }
+
+        l1_table[idx] = cpu_to_le64(cluster_off >> BDRV_SECTOR_BITS);
+        offset = end;
+    }
+
+    *buf_size -= buf_used;
+    *buf += buf_used;
+
+end:
+    qemu_vfree(bm_buf);
+}
+
+void GRAPH_RDLOCK
+parallels_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp)
+{
+    BDRVParallelsState *s = bs->opaque;
+    BdrvDirtyBitmap *bitmap;
+    ParallelsFormatExtensionHeader *eh;
+    int remaining = s->cluster_size;
+    uint8_t *buf, *pos;
+    int64_t header_off, alloc_size = 1;
+    g_autofree uint8_t *hash = NULL;
+    size_t hash_len = 0;
+    int ret;
+
+    s->header->ext_off = 0;
+
+    if (!bdrv_has_named_bitmaps(bs)) {
+        return;
+    }
+
+    buf = qemu_blockalign0(bs, s->cluster_size);
+
+    eh = (ParallelsFormatExtensionHeader *)buf;
+    pos = buf + sizeof(*eh);
+
+    eh->magic = cpu_to_le64(PARALLELS_FORMAT_EXTENSION_MAGIC);
+
+    FOR_EACH_DIRTY_BITMAP(bs, bitmap) {
+        parallels_save_bitmap(bs, bitmap, &pos, &remaining);
+    }
+
+    header_off = parallels_allocate_host_clusters(bs, &alloc_size);
+    if (header_off < 0) {
+        error_report("Can't save dirty bitmap: cluster allocation error");
+        ret = header_off;
+        goto end;
+    }
+
+    ret = qcrypto_hash_bytes(QCRYPTO_HASH_ALG_MD5,
+                             (const char *)(buf + sizeof(*eh)),
+                             s->cluster_size - sizeof(*eh),
+                             &hash, &hash_len, errp);
+    if (ret < 0 || hash_len != sizeof(eh->check_sum)) {
+        error_report("Can't save dirty bitmap: hash error");
+        ret = -EINVAL;
+        goto end;
+    }
+    memcpy(eh->check_sum, hash, hash_len);
+
+    ret = bdrv_pwrite(bs->file, header_off, s->cluster_size, buf, 0);
+    if (ret < 0) {
+        error_report("Can't save dirty bitmap: IO error");
+        parallels_mark_unused(bs, s->used_bmap, s->used_bmap_size,
+                              header_off, 1);
+        goto end;
+    }
+
+    s->header->ext_off = cpu_to_le64(header_off / BDRV_SECTOR_SIZE);
+end:
+    qemu_vfree(buf);
+}
+
+bool coroutine_fn parallels_co_can_store_new_dirty_bitmap(BlockDriverState *bs,
+                                                          const char *name,
+                                                          uint32_t granularity,
+                                                          Error **errp)
+{
+    if (bdrv_find_dirty_bitmap(bs, name)) {
+        error_setg(errp, "Bitmap already exists: %s", name);
+        return false;
+    }
+
+    return true;
+}
diff --git a/block/parallels.c b/block/parallels.c
index f38dd2309c..a49922c6a7 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -1466,14 +1466,25 @@ fail:
 static int GRAPH_RDLOCK parallels_inactivate(BlockDriverState *bs)
 {
     BDRVParallelsState *s = bs->opaque;
+    Error *err = NULL;
     int ret;
 
+    parallels_store_persistent_dirty_bitmaps(bs, &err);
+    if (err != NULL) {
+        error_reportf_err(err, "Lost persistent bitmaps during "
+                          "inactivation of node '%s': ",
+                          bdrv_get_device_or_node_name(bs));
+    }
+
     s->header->inuse = 0;
     parallels_update_header(bs);
 
     /* errors are ignored, so we might as well pass exact=true */
-    ret = bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS, true,
-                        PREALLOC_MODE_OFF, 0, NULL);
+    ret = bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS,
+                        true, PREALLOC_MODE_OFF, 0, NULL);
+    if (ret < 0) {
+        error_report("Failed to truncate image: %s", strerror(-ret));
+    }
 
     return ret;
 }
@@ -1525,6 +1536,7 @@ static BlockDriver bdrv_parallels = {
     .bdrv_co_pdiscard           = parallels_co_pdiscard,
     .bdrv_co_pwrite_zeroes      = parallels_co_pwrite_zeroes,
     .bdrv_inactivate            = parallels_inactivate,
+    .bdrv_co_can_store_new_dirty_bitmap = parallels_co_can_store_new_dirty_bitmap,
 };
 
 static void bdrv_parallels_init(void)
diff --git a/block/parallels.h b/block/parallels.h
index 493c89e976..9db4f5c908 100644
--- a/block/parallels.h
+++ b/block/parallels.h
@@ -101,5 +101,10 @@ int64_t GRAPH_RDLOCK parallels_allocate_host_clusters(BlockDriverState *bs,
 int GRAPH_RDLOCK
 parallels_read_format_extension(BlockDriverState *bs, int64_t ext_off,
                                 Error **errp);
+void GRAPH_RDLOCK
+parallels_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
+bool coroutine_fn
+parallels_co_can_store_new_dirty_bitmap(BlockDriverState *bs, const char *name,
+                                        uint32_t granularity, Error **errp);
 
 #endif
-- 
2.40.1