sheepdog: implement .bdrv_get_allocated_file_size

With this patch, qemu-img info sheepdog:image will show disk size for sheepdog
images.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: NLiu Yuan <namei.unix@gmail.com>
Reviewed-by: NMORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/sheepdog.c

@@ -2407,6 +2407,22 @@ sd_co_get_block_status(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
     return ret;
 }
 
+static int64_t sd_get_allocated_file_size(BlockDriverState *bs)
+{
+    BDRVSheepdogState *s = bs->opaque;
+    SheepdogInode *inode = &s->inode;
+    unsigned long i, last = DIV_ROUND_UP(inode->vdi_size, SD_DATA_OBJ_SIZE);
+    uint64_t size = 0;
+
+    for (i = 0; i < last; i++) {
+        if (inode->data_vdi_id[i] == 0) {
+            continue;
+        }
+        size += SD_DATA_OBJ_SIZE;
+    }
+    return size;
+}
+
 static QEMUOptionParameter sd_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
@@ -2436,6 +2452,7 @@ static BlockDriver bdrv_sheepdog = {
     .bdrv_create    = sd_create,
     .bdrv_has_zero_init = bdrv_has_zero_init_1,
     .bdrv_getlength = sd_getlength,
+    .bdrv_get_allocated_file_size = sd_get_allocated_file_size,
     .bdrv_truncate  = sd_truncate,
 
     .bdrv_co_readv  = sd_co_readv,
@@ -2465,6 +2482,7 @@ static BlockDriver bdrv_sheepdog_tcp = {
     .bdrv_create    = sd_create,
     .bdrv_has_zero_init = bdrv_has_zero_init_1,
     .bdrv_getlength = sd_getlength,
+    .bdrv_get_allocated_file_size = sd_get_allocated_file_size,
     .bdrv_truncate  = sd_truncate,
 
     .bdrv_co_readv  = sd_co_readv,
@@ -2494,6 +2512,7 @@ static BlockDriver bdrv_sheepdog_unix = {
     .bdrv_create    = sd_create,
     .bdrv_has_zero_init = bdrv_has_zero_init_1,
     .bdrv_getlength = sd_getlength,
+    .bdrv_get_allocated_file_size = sd_get_allocated_file_size,
     .bdrv_truncate  = sd_truncate,
 
     .bdrv_co_readv  = sd_co_readv,