qcow2: Add list of bitmaps to ImageInfoSpecificQCow2

In the 'Format specific information' section of the 'qemu-img info'
command output, the supplemental information about existing QCOW2
bitmaps will be shown, such as a bitmap name, flags and granularity:

image: /vz/vmprivate/VM1/harddisk.hdd
file format: qcow2
virtual size: 64G (68719476736 bytes)
disk size: 3.0M
cluster_size: 1048576
Format specific information:
    compat: 1.1
    lazy refcounts: true
    bitmaps:
        [0]:
            flags:
                [0]: in-use
                [1]: auto
            name: back-up1
            granularity: 65536
        [1]:
            flags:
                [0]: in-use
                [1]: auto
            name: back-up2
            granularity: 65536
    refcount bits: 16
    corrupt: false

Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <1549638368-530182-3-git-send-email-andrey.shinkevich@virtuozzo.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 76 insertions, 0 deletions

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index b946301..3ee524d 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -1006,6 +1006,82 @@ fail:
     return false;
 }
 
+
+static Qcow2BitmapInfoFlagsList *get_bitmap_info_flags(uint32_t flags)
+{
+    Qcow2BitmapInfoFlagsList *list = NULL;
+    Qcow2BitmapInfoFlagsList **plist = &list;
+    int i;
+
+    static const struct {
+        int bme;  /* Bitmap directory entry flags */
+        int info; /* The flags to report to the user */
+    } map[] = {
+        { BME_FLAG_IN_USE, QCOW2_BITMAP_INFO_FLAGS_IN_USE },
+        { BME_FLAG_AUTO,   QCOW2_BITMAP_INFO_FLAGS_AUTO },
+    };
+
+    int map_size = ARRAY_SIZE(map);
+
+    for (i = 0; i < map_size; ++i) {
+        if (flags & map[i].bme) {
+            Qcow2BitmapInfoFlagsList *entry =
+                g_new0(Qcow2BitmapInfoFlagsList, 1);
+            entry->value = map[i].info;
+            *plist = entry;
+            plist = &entry->next;
+            flags &= ~map[i].bme;
+        }
+    }
+    /* Check if the BME_* mapping above is complete */
+    assert(!flags);
+
+    return list;
+}
+
+/*
+ * qcow2_get_bitmap_info_list()
+ * Returns a list of QCOW2 bitmap details.
+ * In case of no bitmaps, the function returns NULL and
+ * the @errp parameter is not set.
+ * When bitmap information can not be obtained, the function returns
+ * NULL and the @errp parameter is set.
+ */
+Qcow2BitmapInfoList *qcow2_get_bitmap_info_list(BlockDriverState *bs,
+                                                Error **errp)
+{
+    BDRVQcow2State *s = bs->opaque;
+    Qcow2BitmapList *bm_list;
+    Qcow2Bitmap *bm;
+    Qcow2BitmapInfoList *list = NULL;
+    Qcow2BitmapInfoList **plist = &list;
+
+    if (s->nb_bitmaps == 0) {
+        return NULL;
+    }
+
+    bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
+                               s->bitmap_directory_size, errp);
+    if (bm_list == NULL) {
+        return NULL;
+    }
+
+    QSIMPLEQ_FOREACH(bm, bm_list, entry) {
+        Qcow2BitmapInfo *info = g_new0(Qcow2BitmapInfo, 1);
+        Qcow2BitmapInfoList *obj = g_new0(Qcow2BitmapInfoList, 1);
+        info->granularity = 1U << bm->granularity_bits;
+        info->name = g_strdup(bm->name);
+        info->flags = get_bitmap_info_flags(bm->flags & ~BME_RESERVED_FLAGS);
+        obj->value = info;
+        *plist = obj;
+        plist = &obj->next;
+    }
+
+    bitmap_list_free(bm_list);
+
+    return list;
+}
+
 int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
                                  Error **errp)
 {