"Kirill A. Shutemov" <kirill.shute...@linux.intel.com> writes:
> Currently we fail getattr request altogether if we can't read
> P9_STATS_GEN for some reason. It breaks valid use cases:
>
> E.g let's assume we have non-readable directory with execution bit set
> on host and we export it to client over 9p On host we can chdir into
> directory, but not open directory on read and list content.
>
> But if client will try to call getattr (as part of chdir(2)) for the
> directory it will fail with -EACCES. It happens because we try to open
> the directory on read to call ioctl(FS_IOC_GETVERSION), it fails and we
> return the error code to client.
>
> It's excessive. The solution is to make P9_STATS_GEN failure non-fatal
> for getattr request. Just don't set P9_STATS_GEN flag in result mask on
> failure.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
> ---
> hw/9pfs/cofile.c | 4 ----
> hw/9pfs/virtio-9p.c | 12 ++++++++++--
> 2 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/hw/9pfs/cofile.c b/hw/9pfs/cofile.c
> index 194c1306c665..2efebf35710f 100644
> --- a/hw/9pfs/cofile.c
> +++ b/hw/9pfs/cofile.c
> @@ -38,10 +38,6 @@ int v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t
> st_mode,
> });
> v9fs_path_unlock(s);
> }
> - /* The ioctl may not be supported depending on the path */
> - if (err == -ENOTTY) {
> - err = 0;
> - }
> return err;
> }
>
> diff --git a/hw/9pfs/virtio-9p.c b/hw/9pfs/virtio-9p.c
> index 8cbb8ae32a03..83e4e9398347 100644
> --- a/hw/9pfs/virtio-9p.c
> +++ b/hw/9pfs/virtio-9p.c
> @@ -1080,10 +1080,18 @@ static void v9fs_getattr(void *opaque)
> /* fill st_gen if requested and supported by underlying fs */
> if (request_mask & P9_STATS_GEN) {
> retval = v9fs_co_st_gen(pdu, &fidp->path, stbuf.st_mode,
> &v9stat_dotl);
> - if (retval < 0) {
> + switch (retval) {
> + case 0:
> + /* we have valid st_gen: update result mask */
> + v9stat_dotl.st_result_mask |= P9_STATS_GEN;
> + break;
> + case -EINTR:
> + /* request cancelled, e.g. by Tflush */
> goto out;
> + default:
> + /* failed to get st_gen: not fatal, ignore */
> + break;
> }
> - v9stat_dotl.st_result_mask |= P9_STATS_GEN;
> }
> retval = pdu_marshal(pdu, offset, "A", &v9stat_dotl);
> if (retval < 0) {
> --
> 1.8.5.2
