nfsd4: fix error return when pseudoroot missing

We really shouldn't hit this case at all, and forthcoming kernel and
nfs-utils changes should eliminate this case; if it does happen,
consider it a bug rather than reporting an error that doesn't really
make sense for the operation (since there's no reason for a server to be
accepting v4 traffic yet have no root filehandle).

Also move some exp_pseudoroot code into a helper function while we're
here.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 18 insertions, 4 deletions

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index c1c9e035d4a4..b73baba3fb97 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -1320,6 +1320,23 @@ rqst_exp_parent(struct svc_rqst *rqstp, struct path *path)
         return exp;
 }
 
+static struct svc_export *find_fsidzero_export(struct svc_rqst *rqstp)
+{
+        struct svc_export *exp;
+        u32 fsidv[2];
+
+        mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
+
+        exp = rqst_exp_find(rqstp, FSID_NUM, fsidv);
+        /*
+         * We shouldn't have accepting an nfsv4 request at all if we
+         * don't have a pseudoexport!:
+         */
+        if (IS_ERR(exp) && PTR_ERR(exp) == -ENOENT)
+                exp = ERR_PTR(-ESERVERFAULT);
+        return exp;
+}
+
 /*
  * Called when we need the filehandle for the root of the pseudofs,
  * for a given NFSv4 client.   The root is defined to be the
@@ -1330,11 +1347,8 @@ exp_pseudoroot(struct svc_rqst *rqstp, struct svc_fh *fhp)
 {
         struct svc_export *exp;
         __be32 rv;
-        u32 fsidv[2];
-
-        mk_fsid(FSID_NUM, fsidv, 0, 0, 0, NULL);
 
-        exp = rqst_exp_find(rqstp, FSID_NUM, fsidv);
+        exp = find_fsidzero_export(rqstp);
         if (IS_ERR(exp))
                 return nfserrno(PTR_ERR(exp));
         rv = fh_compose(fhp, exp, exp->ex_path.dentry, NULL);