nfs4: fix referrals on mounts that use IPv6 addrs

All referrals (IPv4 addr, IPv6 addr, and DNS) are broken on mounts of
IPv6 addresses, because validation code uses a path that is parsed
from the dev_name ("<server>:<path>") by splitting on the first colon and
colons are used in IPv6 addrs.
This patch ignores colons within IPv6 addresses that are escaped by '[' and ']'.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 27 insertions, 3 deletions

diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 9c8eca315f43..7483a177dc97 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -52,6 +52,30 @@ Elong:
 }
 
 /*
+ * return the path component of "<server>:<path>"
+ *  nfspath - the "<server>:<path>" string
+ *  end - one past the last char that could contain "<server>:"
+ * returns NULL on failure
+ */
+static char *nfs_path_component(const char *nfspath, const char *end)
+{
+        char *p;
+
+        if (*nfspath == '[') {
+                /* parse [] escaped IPv6 addrs */
+                p = strchr(nfspath, ']');
+                if (p != NULL && ++p < end && *p == ':')
+                        return p + 1;
+        } else {
+                /* otherwise split on first colon */
+                p = strchr(nfspath, ':');
+                if (p != NULL && p < end)
+                        return p + 1;
+        }
+        return NULL;
+}
+
+/*
  * Determine the mount path as a string
  */
 static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
@@ -59,9 +83,9 @@ static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
         char *limit;
         char *path = nfs_path(&limit, dentry, buffer, buflen);
         if (!IS_ERR(path)) {
-                char *colon = strchr(path, ':');
-                if (colon && colon < limit)
-                        path = colon + 1;
+                char *path_component = nfs_path_component(path, limit);
+                if (path_component)
+                        return path_component;
         }
         return path;
 }