[PATCH v4 1/2] block: Fixes nfs compiling error on msys2/mingw

[Yonggang Luo <luoyonggang@gmail.com>]

These compiling errors are fixed:
../block/nfs.c:27:10: fatal error: poll.h: No such file or directory
   27 | #include <poll.h>
      |          ^~~~~~~~
compilation terminated.

../block/nfs.c:63:5: error: unknown type name 'blkcnt_t'
   63 |     blkcnt_t st_blocks;
      |     ^~~~~~~~
../block/nfs.c: In function 'nfs_client_open':
../block/nfs.c:550:27: error: 'struct _stat64' has no member named 'st_blocks'
  550 |     client->st_blocks = st.st_blocks;
      |                           ^
../block/nfs.c: In function 'nfs_get_allocated_file_size':
../block/nfs.c:751:41: error: 'struct _stat64' has no member named 'st_blocks'
  751 |     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
      |                                         ^
../block/nfs.c: In function 'nfs_reopen_prepare':
../block/nfs.c:805:31: error: 'struct _stat64' has no member named 'st_blocks'
  805 |         client->st_blocks = st.st_blocks;
      |                               ^
../block/nfs.c: In function 'nfs_get_allocated_file_size':
../block/nfs.c:752:1: error: control reaches end of non-void function [-Werror=return-type]
  752 | }
      | ^

On msys2/mingw, there is no st_blocks in struct _stat64 yet, we disable the usage of it
on msys2/mingw, and create a typedef long long blkcnt_t; for further implementation

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
---
 block/nfs.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/block/nfs.c b/block/nfs.c
index f86e660374..77905f516d 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -24,7 +24,9 @@
 
 #include "qemu/osdep.h"
 
+#if !defined(_WIN32)
 #include <poll.h>
+#endif
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
 #include "qapi/error.h"
@@ -58,7 +60,7 @@ typedef struct NFSClient {
     bool has_zero_init;
     AioContext *aio_context;
     QemuMutex mutex;
-    blkcnt_t st_blocks;
+    uint64_t st_blocks;
     bool cache_used;
     NFSServer *server;
     char *path;
@@ -545,7 +547,9 @@ static int64_t nfs_client_open(NFSClient *client, BlockdevOptionsNfs *opts,
     }
 
     ret = DIV_ROUND_UP(st.st_size, BDRV_SECTOR_SIZE);
+#if !defined(_WIN32)
     client->st_blocks = st.st_blocks;
+#endif
     client->has_zero_init = S_ISREG(st.st_mode);
     *strp = '/';
     goto out;
@@ -706,6 +710,7 @@ static int nfs_has_zero_init(BlockDriverState *bs)
     return client->has_zero_init;
 }
 
+#if !defined(_WIN32)
 /* Called (via nfs_service) with QemuMutex held.  */
 static void
 nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,
@@ -748,6 +753,7 @@ static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
 
     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 }
+#endif
 
 static int coroutine_fn
 nfs_file_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
@@ -800,7 +806,9 @@ static int nfs_reopen_prepare(BDRVReopenState *state,
                        nfs_get_error(client->context));
             return ret;
         }
+#if !defined(_WIN32)
         client->st_blocks = st.st_blocks;
+#endif
     }
 
     return 0;
@@ -869,7 +877,10 @@ static BlockDriver bdrv_nfs = {
     .create_opts                    = &nfs_create_opts,
 
     .bdrv_has_zero_init             = nfs_has_zero_init,
+/* libnfs does not provide the allocated filesize of a file on win32. */
+#if !defined(_WIN32)
     .bdrv_get_allocated_file_size   = nfs_get_allocated_file_size,
+#endif
     .bdrv_co_truncate               = nfs_file_co_truncate,
 
     .bdrv_file_open                 = nfs_file_open,
-- 
2.28.0.windows.1