NFS: Allow NFSROOT debugging messages to be enabled dynamically

As a convenience, introduce a kernel command line option to enable
NFSROOT debugging messages.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 13 insertions, 6 deletions

diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 8e7d623173a9..460df3652889 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -67,6 +67,7 @@
  *                              NFS over TCP.
  *      Fabian Frederick:       Option parser rebuilt (using parser lib)
  *      Chuck Lever     :       Use super.c's text-based mount option parsing
+ *      Chuck Lever     :       Add "nfsrootdebug".
  */
 
 #include <linux/types.h>
@@ -80,8 +81,6 @@
 
 #include "internal.h"
 
-/* Define this to allow debugging output */
-#undef NFSROOT_DEBUG
 #define NFSDBG_FACILITY NFSDBG_ROOT
 
 /* Default path we try to mount. "%s" gets replaced by our IP address */
@@ -103,6 +102,18 @@ static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
 static char nfs_root_device[NFS_MAXPATHLEN + 1] __initdata = "";
 
 /*
+ * When the "nfsrootdebug" kernel command line option is specified,
+ * enable debugging messages for NFSROOT.
+ */
+static int __init nfs_root_debug(char *__unused)
+{
+        nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
+        return 1;
+}
+
+__setup("nfsrootdebug", nfs_root_debug);
+
+/*
  *  Parse NFS server and directory information passed on the kernel
  *  command line.
  *
@@ -282,10 +293,6 @@ out_devnametoolong:
  */
 int __init nfs_root_data(char **root_device, char **root_data)
 {
-#ifdef NFSROOT_DEBUG
-        nfs_debug |= NFSDBG_ROOT | NFSDBG_MOUNT;
-#endif  /* NFSROOT_DEBUG */
-
         servaddr = root_server_addr;
         if (servaddr == htonl(INADDR_NONE)) {
                 printk(KERN_ERR "Root-NFS: no NFS server address\n");