Declare modalias for nfs4filelayout to support auto-loading of modules.

Hi,
I had a brief look at configuring pnfs recently and wondered why

http://wiki.linux-nfs.org/wiki/index.php/PNFS_Setup_Instructions

suggested that the layout module should be explicitly 'modprobe'd when that sort of thing is normally automatic.
pnfs.c makes the appropriate 'request-module' call, but there is no MODULE_ALIAS to link the relevant module with the requested name.

This patch adds the required MODULE_ALIAS. It has only been compile-tested (my interest is as yet only theoretical :-)

Thanks,
NeilBrown

From: NeilBrown <[email protected]>
Date: Mon, 16 May 2011 10:55:57 +1000
Subject: [PATCH] Declare modalias for nfs4filelayout to support auto-loading of modules.

pnfs.c uses 'request_module' with the name
nfs-layouttype4-1

when it actually wants
nfs4filelayout

so give the latter a "MODULE_ALIAS" so it can be found with the former name.

This avoids needing to add an alais to /etc/modprobe.d/...

---
 fs/nfs/nfs4filelayout.c |    1 +
 fs/nfs/pnfs.h           |    2 ++
 2 files changed, 3 insertions(+), 0 deletions(-)

index be79dc9..86c2f5f 100644
@@ -873,6 +873,7 @@ static struct pnfs_layoutdriver_type filelayout_type = {
 	.read_pagelist		= filelayout_read_pagelist,
 	.write_pagelist		= filelayout_write_pagelist,
 };
+NFSV4_LAYOUT_MODULE_ALIAS(LAYOUT_NFSV4_1_FILES);
 
 static int __init nfs4filelayout_init(void)
 {

index 0c015ba..1c2a1f1 100644
@@ -55,6 +55,8 @@ enum pnfs_try_status {
 #ifdef CONFIG_NFS_V4_1
 
 #define LAYOUT_NFSV4_1_MODULE_PREFIX "nfs-layouttype4"
+#define NFSV4_LAYOUT_MODULE_ALIAS(id) \
+	MODULE_ALIAS(LAYOUT_NFSV4_1_MODULE_PREFIX "-" #id)
 
 enum {
 	NFS_LAYOUT_RO_FAILED = 0,	/* get ro layout failed stop trying */

1.7.3.4