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>

diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt
index f2430a7..90c71c6 100644 (file)
--- a/Documentation/filesystems/nfs/nfsroot.txt
+++ b/Documentation/filesystems/nfs/nfsroot.txt
@@ -159,6 +159,28 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf>
                 Default: any
 
 
+nfsrootdebug
+
+  This parameter enables debugging messages to appear in the kernel
+  log at boot time so that administrators can verify that the correct
+  NFS mount options, server address, and root path are passed to the
+  NFS client.
+
+
+rdinit=<executable file>
+
+  To specify which file contains the program that starts system
+  initialization, administrators can use this command line parameter.
+  The default value of this parameter is "/init".  If the specified
+  file exists and the kernel can execute it, root filesystem related
+  kernel command line parameters, including `nfsroot=', are ignored.
+
+  A description of the process of mounting the root file system can be
+  found in:
+
+    Documentation/early-userspace/README
+
+
 
 
 3.) Boot Loader

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f084af0..0fe70b2 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1532,12 +1532,15 @@ and is between 256 and 4096 characters. It is defined in the file
                        1 to enable accounting
                        Default value is 0.
 
-       nfsaddrs=       [NFS]
+       nfsaddrs=       [NFS] Deprecated.  Use ip= instead.
                        See Documentation/filesystems/nfs/nfsroot.txt.
 
        nfsroot=        [NFS] nfs root filesystem for disk-less boxes.
                        See Documentation/filesystems/nfs/nfsroot.txt.
 
+       nfsrootdebug    [NFS] enable nfsroot debugging messages.
+                       See Documentation/filesystems/nfs/nfsroot.txt.
+
        nfs.callback_tcpport=
                        [NFS] set the TCP port on which the NFSv4 callback
                        channel should listen.

diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 8e7d623..460df36 100644 (file)
--- 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 */
@@ -102,6 +101,18 @@ static char nfs_export_path[NFS_MAXPATHLEN + 1] __initdata = "";
 /* server:export path string passed to super.c */
 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");