4 files changed, 20 insertions, 9 deletions

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 59b133c5d652..a54fe51c1dfb 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -353,8 +353,9 @@ extern void nfs_sb_active(struct super_block *sb);
 extern void nfs_sb_deactive(struct super_block *sb);
 
 /* namespace.c */
+#define NFS_PATH_CANONICAL 1
 extern char *nfs_path(char **p, struct dentry *dentry,
-                      char *buffer, ssize_t buflen);
+                      char *buffer, ssize_t buflen, unsigned flags);
 extern struct vfsmount *nfs_d_automount(struct path *path);
 struct vfsmount *nfs_submount(struct nfs_server *, struct dentry *,
                               struct nfs_fh *, struct nfs_fattr *);
@@ -498,7 +499,7 @@ static inline char *nfs_devname(struct dentry *dentry,
                                 char *buffer, ssize_t buflen)
 {
         char *dummy;
-        return nfs_path(&dummy, dentry, buffer, buflen);
+        return nfs_path(&dummy, dentry, buffer, buflen, NFS_PATH_CANONICAL);
 }
 
 /*
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 655925373b91..dd057bc6b65b 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -33,6 +33,7 @@ int nfs_mountpoint_expiry_timeout = 500 * HZ;
  * @dentry - pointer to dentry
  * @buffer - result buffer
  * @buflen - length of buffer
+ * @flags - options (see below)
  *
  * Helper function for constructing the server pathname
  * by arbitrary hashed dentry.
@@ -40,8 +41,14 @@ int nfs_mountpoint_expiry_timeout = 500 * HZ;
  * This is mainly for use in figuring out the path on the
  * server side when automounting on top of an existing partition
  * and in generating /proc/mounts and friends.
+ *
+ * Supported flags:
+ * NFS_PATH_CANONICAL: ensure there is exactly one slash after
+ *                     the original device (export) name
+ *                     (if unset, the original name is returned verbatim)
  */
-char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen)
+char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
+               unsigned flags)
 {
         char *end;
         int namelen;
@@ -74,7 +81,7 @@ rename_retry:
                 rcu_read_unlock();
                 goto rename_retry;
         }
-        if (*end != '/') {
+        if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
                 if (--buflen < 0) {
                         spin_unlock(&dentry->d_lock);
                         rcu_read_unlock();
@@ -91,9 +98,11 @@ rename_retry:
                 return end;
         }
         namelen = strlen(base);
-        /* Strip off excess slashes in base string */
-        while (namelen > 0 && base[namelen - 1] == '/')
-                namelen--;
+        if (flags & NFS_PATH_CANONICAL) {
+                /* Strip off excess slashes in base string */
+                while (namelen > 0 && base[namelen - 1] == '/')
+                        namelen--;
+        }
         buflen -= namelen;
         if (buflen < 0) {
                 spin_unlock(&dentry->d_lock);
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 79fbb61ce202..1e09eb78543b 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -81,7 +81,8 @@ static char *nfs_path_component(const char *nfspath, const char *end)
 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
 {
         char *limit;
-        char *path = nfs_path(&limit, dentry, buffer, buflen);
+        char *path = nfs_path(&limit, dentry, buffer, buflen,
+                              NFS_PATH_CANONICAL);
         if (!IS_ERR(path)) {
                 char *path_component = nfs_path_component(path, limit);
                 if (path_component)
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index e831bce49766..13c2a5be4765 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -771,7 +771,7 @@ int nfs_show_devname(struct seq_file *m, struct dentry *root)
         int err = 0;
         if (!page)
                 return -ENOMEM;
-        devname = nfs_path(&dummy, root, page, PAGE_SIZE);
+        devname = nfs_path(&dummy, root, page, PAGE_SIZE, 0);
         if (IS_ERR(devname))
                 err = PTR_ERR(devname);
         else