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>

diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 9c8eca3..7483a17 100644 (file)
--- 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;
 }