Merge tag 'nfsd-4.12' of git://linux-nfs.org/~bfields/linux

[sfrench/cifs-2.6.git] / fs / nfsd / vfs.c

diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 9aaf6ca7756998f9f872db91e7d1ef5f92351e8c..2be32955d7f27d285d0cba1dad39e88c885dc7e0 100644 (file)
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -94,6 +94,12 @@ nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
        err = follow_down(&path);
        if (err < 0)
                goto out;
+       if (path.mnt == exp->ex_path.mnt && path.dentry == dentry &&
+           nfsd_mountpoint(dentry, exp) == 2) {
+               /* This is only a mountpoint in some other namespace */
+               path_put(&path);
+               goto out;
+       }
 
        exp2 = rqst_exp_get_by_name(rqstp, &path);
        if (IS_ERR(exp2)) {
@@ -167,16 +173,26 @@ 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.
+ * We return:
+ * '1' if this dentry *must* be an export point,
+ * '2' if it might be, if there is really a mount here, and
+ * '0' if there is no chance of an export point here.
  */
 int nfsd_mountpoint(struct dentry *dentry, struct svc_export *exp)
 {
-       if (d_mountpoint(dentry))
+       if (!d_inode(dentry))
+               return 0;
+       if (exp->ex_flags & NFSEXP_V4ROOT)
                return 1;
        if (nfsd4_is_junction(dentry))
                return 1;
-       if (!(exp->ex_flags & NFSEXP_V4ROOT))
-               return 0;
-       return d_inode(dentry) != NULL;
+       if (d_mountpoint(dentry))
+               /*
+                * Might only be a mountpoint in a different namespace,
+                * but we need to check.
+                */
+               return 2;
+       return 0;
 }
 
 __be32