Current write_zeroes implementation is good enough to satisfy this flag too

Signed-off-by: Anton Nefedov <anton.nefedov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
---
 block/file-posix.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/block/file-posix.c b/block/file-posix.c
index 36ee89e..c36e156 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -558,7 +558,10 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     }
     if (S_ISREG(st.st_mode)) {
         s->discard_zeroes = true;
+#ifdef CONFIG_FALLOCATE
         s->has_fallocate = true;
+        bs->supported_zero_flags |= BDRV_REQ_ALLOCATE;
+#endif
     }
     if (S_ISBLK(st.st_mode)) {
 #ifdef BLKDISCARDZEROES
@@ -593,6 +596,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
 #ifdef CONFIG_XFS
     if (platform_test_xfs_fd(s->fd)) {
         s->is_xfs = true;
+        bs->supported_zero_flags |= BDRV_REQ_ALLOCATE;
     }
 #endif
 
@@ -1413,6 +1417,10 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
         }
         s->has_fallocate = false;
     }
+
+    if (!s->has_fallocate) {
+        aiocb->bs->supported_zero_flags &= ~BDRV_REQ_ALLOCATE;
+    }
 #endif
 
     return -ENOTSUP;
-- 
2.7.4