Re: [Qemu-devel] [PATCH 1.0] 9pfs: improve portability to older systems

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On Mon, 21 Nov 2011 09:29:11 +0100, Paolo Bonzini <pbonzini@redhat.com> wrote:
> Small requirements on "new" features have percolated to virtio-9p-local.c.
> In particular, the utimensat wrapper actually only supports dirfd = AT_FDCWD
> and flags = AT_SYMLINK_NOFOLLOW in the fallback code.  Remove the arguments
> so that virtio-9p-local.c will not use AT_* constants.
> 
> At the same time, fail local_ioc_getversion if the ioctl is not supported
> by the host.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  hw/9pfs/virtio-9p-local.c |    7 +++++--
>  oslib-posix.c             |    5 ++---
>  qemu-os-posix.h           |    3 +--
>  3 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
> index 7f1c089..cbd07e8 100644
> --- a/hw/9pfs/virtio-9p-local.c
> +++ b/hw/9pfs/virtio-9p-local.c
> @@ -583,8 +583,7 @@ static int local_utimensat(FsContext *s, V9fsPath *fs_path,
>      char buffer[PATH_MAX];
>      char *path = fs_path->data;
> 
> -    return qemu_utimensat(AT_FDCWD, rpath(s, path, buffer), buf,
> -                          AT_SYMLINK_NOFOLLOW);
> +    return qemu_utimens(rpath(s, path, buffer), buf);
>  }
> 
>  static int local_remove(FsContext *ctx, const char *path)
> @@ -694,6 +693,7 @@ static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
>                                  mode_t st_mode, uint64_t *st_gen)
>  {
>      int err;
> +#ifdef FS_IOC_GETVERSION
>      V9fsFidOpenState fid_open;
> 
>      /*
> @@ -709,6 +709,9 @@ static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
>      }
>      err = ioctl(fid_open.fd, FS_IOC_GETVERSION, st_gen);
>      local_close(ctx, &fid_open);
> +#else
> +    err = -ENOTTY;
> +#endif
>      return err;


I guess we can also make sure we don't  call local_ioc_getversion at
all. 

diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
index 0da3bdd..1c349af 100644
--- a/hw/9pfs/virtio-9p-local.c
+++ b/hw/9pfs/virtio-9p-local.c
@@ -714,10 +714,14 @@ static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
 
 static int local_init(FsContext *ctx)
 {
-    int err;
+    int err = 0;
     struct statfs stbuf;
 
     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
+#ifdef FS_IOC_GETVERSION
+    /*
+     * use ioc_getversion only if the iocl is definied
+     */
     err = statfs(ctx->fs_root, &stbuf);
     if (!err) {
         switch (stbuf.f_type) {
@@ -729,6 +733,7 @@ static int local_init(FsContext *ctx)
             break;
         }
     }
+#endif
     return err;
 }
 


We would also require same changes for virtio-9p-handle.c right ?

-aneesh