nfsd: filter readdir results in V4ROOT case

As with lookup, we treat every boject as a mountpoint and pretend it
doesn't exist if it isn't exported.

The preexisting code here is confusing, but I haven't yet figured out
how to make it clearer.

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

3 files changed, 9 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index cab97803110..a8587e90fd5 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2196,11 +2196,14 @@ nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
          * we will not follow the cross mount and will fill the attribtutes
          * directly from the mountpoint dentry.
          */
-        if (d_mountpoint(dentry) && !attributes_need_mount(cd->rd_bmval))
-                ignore_crossmnt = 1;
-        else if (d_mountpoint(dentry)) {
+        if (nfsd_mountpoint(dentry, exp)) {
                 int err;
 
+                if (!(exp->ex_flags & NFSEXP_V4ROOT)
+                                && !attributes_need_mount(cd->rd_bmval)) {
+                        ignore_crossmnt = 1;
+                        goto out_encode;
+                }
                 /*
                  * Why the heck aren't we just using nfsd_lookup??
                  * Different "."/".." handling?  Something else?
@@ -2216,6 +2219,7 @@ nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
                         goto out_put;
 
         }
+out_encode:
         nfserr = nfsd4_encode_fattr(NULL, exp, dentry, p, buflen, cd->rd_bmval,
                                         cd->rd_rqstp, ignore_crossmnt);
 out_put:
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index eaf2f0dca12..a0015a958ae 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -170,7 +170,7 @@ static int nfsd_lookup_parent(struct svc_rqst *rqstp, struct dentry *dparent, st
  * For nfsd purposes, we treat V4ROOT exports as though there was an
  * export at *every* directory.
  */
-static int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
+int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
 {
         if (d_mountpoint(dentry))
                 return 1;
diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h
index b8011fd2fca..f4fa6d351bb 100644
--- a/fs/nfsd/vfs.h
+++ b/fs/nfsd/vfs.h
@@ -40,6 +40,7 @@ __be32		 nfsd_lookup_dentry(struct svc_rqst *, struct svc_fh *,
                                 struct svc_export **, struct dentry **);
 __be32          nfsd_setattr(struct svc_rqst *, struct svc_fh *,
                                 struct iattr *, int, time_t);
+int nfsd_mountpoint(struct dentry *, struct svc_export *);
 #ifdef CONFIG_NFSD_V4
 __be32          nfsd4_set_nfs4_acl(struct svc_rqst *, struct svc_fh *,
                     struct nfs4_acl *);