[Qemu-devel] [PATCH v2 2/2] sheepdog: implement .bdrv_co_is_allocated()

[Liu Yuan <namei.unix@gmail.com>]

From: Liu Yuan <tailai.ly@taobao.com>

Cc: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
---
 block/sheepdog.c |   36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/block/sheepdog.c b/block/sheepdog.c
index 0b700a3..0dbf039 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2137,6 +2137,39 @@ static coroutine_fn int sd_co_discard(BlockDriverState *bs, int64_t sector_num,
     return acb->ret;
 }
 
+static coroutine_fn int
+sd_co_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
+                   int *pnum)
+{
+    BDRVSheepdogState *s = bs->opaque;
+    SheepdogInode *inode = &s->inode;
+    unsigned long start = sector_num * BDRV_SECTOR_SIZE / SD_DATA_OBJ_SIZE, idx,
+                  end = DIV_ROUND_UP((sector_num + nb_sectors) *
+                                     BDRV_SECTOR_SIZE, SD_DATA_OBJ_SIZE);
+    int ret = 1;
+
+    for (idx = start; idx <= end; idx++) {
+        if (inode->data_vdi_id[idx] == 0) {
+            break;
+        }
+    }
+    if (idx == start) {
+        /* Get te longest length of unallocated sectors */
+        ret = 0;
+        for (idx = start + 1; idx <= end; idx++) {
+            if (inode->data_vdi_id[idx] != 0) {
+                break;
+            }
+        }
+    }
+
+    *pnum = (idx - start) * SD_DATA_OBJ_SIZE / BDRV_SECTOR_SIZE;
+    if (*pnum > nb_sectors) {
+        *pnum = nb_sectors;
+    }
+    return ret;
+}
+
 static QEMUOptionParameter sd_create_options[] = {
     {
         .name = BLOCK_OPT_SIZE,
@@ -2170,6 +2203,7 @@ static BlockDriver bdrv_sheepdog = {
     .bdrv_co_writev = sd_co_writev,
     .bdrv_co_flush_to_disk  = sd_co_flush_to_disk,
     .bdrv_co_discard = sd_co_discard,
+    .bdrv_co_is_allocated = sd_co_is_allocated,
 
     .bdrv_snapshot_create   = sd_snapshot_create,
     .bdrv_snapshot_goto     = sd_snapshot_goto,
@@ -2196,6 +2230,7 @@ static BlockDriver bdrv_sheepdog_tcp = {
     .bdrv_co_writev = sd_co_writev,
     .bdrv_co_flush_to_disk  = sd_co_flush_to_disk,
     .bdrv_co_discard = sd_co_discard,
+    .bdrv_co_is_allocated = sd_co_is_allocated,
 
     .bdrv_snapshot_create   = sd_snapshot_create,
     .bdrv_snapshot_goto     = sd_snapshot_goto,
@@ -2222,6 +2257,7 @@ static BlockDriver bdrv_sheepdog_unix = {
     .bdrv_co_writev = sd_co_writev,
     .bdrv_co_flush_to_disk  = sd_co_flush_to_disk,
     .bdrv_co_discard = sd_co_discard,
+    .bdrv_co_is_allocated = sd_co_is_allocated,
 
     .bdrv_snapshot_create   = sd_snapshot_create,
     .bdrv_snapshot_goto     = sd_snapshot_goto,
-- 
1.7.9.5