Re: [PATCH v3 7/7] tests/9pfs: check fid being unaffected in fs_walk_2nd_nonexistent

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Sonntag, 13. März 2022 10:28:32 CET Christian Schoenebeck wrote:
> Extend previously added test case by checking that fid is unaffected
> by 'Twalk' request (i.e. when 2nd path component of request being
> invalid). Do that by comparing the QID of root fid with QID of walked
> fid; they should be identical.
> 
> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
>  tests/qtest/virtio-9p-test.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/qtest/virtio-9p-test.c b/tests/qtest/virtio-9p-test.c
> index f6e78d388e..b9c6819d01 100644
> --- a/tests/qtest/virtio-9p-test.c
> +++ b/tests/qtest/virtio-9p-test.c
> @@ -721,14 +721,19 @@ static void fs_version(void *obj, void *data,
> QGuestAllocator *t_alloc) do_version(obj);
>  }
> 
> -static void do_attach(QVirtio9P *v9p)
> +static void do_attach_rqid(QVirtio9P *v9p, v9fs_qid *qid)
>  {
>      P9Req *req;
> 
>      do_version(v9p);
>      req = v9fs_tattach(v9p, 0, getuid(), 0);
>      v9fs_req_wait_for_reply(req, NULL);
> -    v9fs_rattach(req, NULL);
> +    v9fs_rattach(req, qid);
> +}
> +
> +static void do_attach(QVirtio9P *v9p)
> +{
> +    do_attach_rqid(v9p, NULL);
>  }
> 
>  static void fs_attach(void *obj, void *data, QGuestAllocator *t_alloc)
> @@ -1101,19 +1106,22 @@ static void fs_walk_2nd_nonexistent(void *obj, void
> *data, {
>      QVirtio9P *v9p = obj;
>      alloc = t_alloc;
> +    v9fs_qid root_qid;
>      uint16_t nwqid;
>      g_autofree v9fs_qid *wqid = NULL;
>      g_autofree char *path = g_strdup_printf(
>          QTEST_V9FS_SYNTH_WALK_FILE "/non-existent", 0
>      );
> 
> -    do_attach(v9p);
> +    do_attach_rqid(v9p, &root_qid);
>      do_walk_rqids(v9p, path, &nwqid, &wqid);
>      /*
>       * The 9p2000 protocol spec says: "nwqid is therefore either nwname or
> the * index of the first elementwise walk that failed."
>       */
>      assert(nwqid == 1);
> +    /* expect fid being unaffected by walk */
> +    g_assert(wqid && wqid[0] && is_same_qid(root_qid, wqid[0]));

Mmm, that's actually not checking whether fid was unaffected by the walk. It 
just checks whether the QID returned by Rwalk equals the root QID, period.

I suggest I leave this check here (just remove the false comment there), it's 
still OK to do that check, but additionally I would send a Tgetatrr on the 
walked fid to do the actual "fid unaffected" check?

I'll wait to see if you spot something else before posting any v4.

>  }
> 
>  static void fs_walk_none(void *obj, void *data, QGuestAllocator *t_alloc)