On Tue, 31 Aug 2010 17:21:31 -0400
Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
> The logic that manages negotiating NFS version and protocol settings
> is getting more complex over time, so let's split this out of
> nfs_try_mount().
>
> This should make Bruce a little happier, as it eliminates the silent
> switch case fall through in nfs_try_mount(). And it should help Neil
> fix some bugs he's found in this logic.
Hi Chuck,
thanks for these..
One question....
.....
> +{
> + int result;
> +
> + /*
> + * Before 2.6.32, the kernel NFS client didn't support
> + * "-t nfs vers=4" mounts, so NFS version 4 cannot be
> + * included when autonegotiating while running on
> + * those kernels.
> + */
> + if (linux_version_code() <= MAKE_VERSION(2, 6, 31))
> + goto fall_back;
> +
> + errno = 0;
> + result = nfs_try_mount_v4(mi);
> + switch (errno) {
Should we not have e.g.
if (result)
return result;
before the switch(errno)?? Typically errno is 'undefined' in no error is
reported.
I realise the current code doesn't have that test either, but I still think
it is wrong not to.
Thanks
NeilBrown
> + case EPROTONOSUPPORT:
> + /* A clear indication that the server or our
> + * client does not support NFS version 4. */
> + goto fall_back;
> + case ENOENT:
> + /* Legacy Linux servers don't export an NFS
> + * version 4 pseudoroot. */
> + goto fall_back;
> + case EPERM:
> + /* Linux servers prior to 2.6.25 may return
> + * EPERM when NFS version 4 is not supported. */
> + goto fall_back;
> + default:
> + return result;
> + }
> +
> +fall_back:
> + return nfs_try_mount_v3v2(mi);
> +}
> +
> +/*
> * This is a single pass through the fg/bg loop.
> *
> * Returns TRUE if successful, otherwise FALSE.
> @@ -758,20 +801,8 @@ static int nfs_try_mount(struct nfsmount_info *mi)
>
> switch (mi->version) {
> case 0:
> - if (linux_version_code() > MAKE_VERSION(2, 6, 31)) {
> - errno = 0;
> - result = nfs_try_mount_v4(mi);
> - if (errno != EPROTONOSUPPORT) {
> - /*
> - * To deal with legacy Linux servers that don't
> - * automatically export a pseudo root, retry
> - * ENOENT errors using version 3. And for
> - * Linux servers prior to 2.6.25, retry EPERM
> - */
> - if (errno != ENOENT && errno != EPERM)
> - break;
> - }
> - }
> + result = nfs_autonegotiate(mi);
> + break;
> case 2:
> case 3:
> result = nfs_try_mount_v3v2(mi);
--
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