Re: reconnect_path fails with EACCES

["J. Bruce Fields" <bfields@xxxxxxxxxxxx>]

On Thu, Aug 09, 2012 at 02:55:28AM +0530, Rajesh Ghanekar wrote:
> Hi,
> I am facing problem with reconnect_path failing with EACCES when doing
> lookup_one_len. I have 2 users goind to same directory, one with uid=0
> and another with uid=xxx. Sometime for uid=0 request, nfsd is still is using
> uid=xxx (as it was used previously), as uid=xxx doesn't have any permissions
> on the directory.
> 
> Should this probably do nfsd_setuser_and_check_port before
> the below code in nfsd_set_fh_dentry()? As it carries older
> fsuid and fsgid, can it create issues. This always happens
> with disconnected dentries.
> 
>         if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
>                 /* Elevate privileges so that the lack of 'r' or 'x'
>                  * permission on some parent directory will
>                  * not stop exportfs_decode_fh from being able
>                  * to reconnect a directory into the dentry cache.
>                  * The same problem can affect "SUBTREECHECK" exports,
>                  * but as nfsd_acceptable depends on correct
>                  * access control settings being in effect, we cannot
>                  * fix that case easily.

Are you exporting with subtree_check or no_subtree_check?  (What does
"exportfs -v" say?)

In the no_subtree_check case, the cap_raise_nfsd_set() is intended to
override file permissions, so the uid and gid shouldn't matter.

--b.
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