nfsroot: make nfsroot to accept the 1024 bytes long directory name

although NFS_MAXPATHLEN is defined to 1024, nfs client hopes to accept
a 1024 byte path, but nfs_root_parms is limited to 256, and the nfs path
will truncated when a user inputs nfs path from kernel cmdline

enlarge nfs_root_parms to 1024, to make it accept the 1024 bytes long
directory name, since nfs_root_parms is defined as _initdata, it will
be released after system bootup
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfsroot.c

@@ -90,7 +90,7 @@
 #define NFS_DEF_OPTIONS		"vers=2,udp,rsize=4096,wsize=4096"
 
 /* Parameters passed from the kernel command line */
-static char nfs_root_parms[256] __initdata = "";
+static char nfs_root_parms[NFS_MAXPATHLEN + 1] __initdata = "";
 
 /* Text-based mount options passed to super.c */
 static char nfs_root_options[256] __initdata = NFS_DEF_OPTIONS;