1 files changed, 26 insertions, 3 deletions

diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index c7b0fdaeac96..f45451eb1e38 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -176,9 +176,24 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
         if (IS_ERR(exp))
                 return nfserrno(PTR_ERR(exp));
 
-        error = nfsd_setuser_and_check_port(rqstp, exp);
-        if (error)
-                goto out;
+        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.
+                 */
+                current->cap_effective =
+                        cap_raise_nfsd_set(current->cap_effective,
+                                           current->cap_permitted);
+        } else {
+                error = nfsd_setuser_and_check_port(rqstp, exp);
+                if (error)
+                        goto out;
+        }
 
         /*
          * Look up the dentry using the NFS file handle.
@@ -215,6 +230,14 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
                 goto out;
         }
 
+        if (exp->ex_flags & NFSEXP_NOSUBTREECHECK) {
+                error = nfsd_setuser_and_check_port(rqstp, exp);
+                if (error) {
+                        dput(dentry);
+                        goto out;
+                }
+        }
+
         if (S_ISDIR(dentry->d_inode->i_mode) &&
                         (dentry->d_flags & DCACHE_DISCONNECTED)) {
                 printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %s/%s\n",