From 278d9b8ba6673e34b7ceb41212cf3e270a04d683 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Wed, 17 Jun 2015 13:00:10 +0200 Subject: fs: nfs: Implement Linux rootarg Add the root= parameter for NFS filesystems. We currently hardcode v3 and tcp which probably needs to become configurable at some point. Signed-off-by: Sascha Hauer --- Documentation/filesystems/nfs.rst | 13 +++++++++++++ fs/nfs.c | 24 ++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/Documentation/filesystems/nfs.rst b/Documentation/filesystems/nfs.rst index f4eda5d13c..4469ac1dff 100644 --- a/Documentation/filesystems/nfs.rst +++ b/Documentation/filesystems/nfs.rst @@ -10,3 +10,16 @@ barebox has readonly support for NFSv3 in UDP mode. Example:: mount -t nfs 192.168.23.4:/home/user/nfsroot /mnt/nfs + +The barebox NFS driver adds a ``linux.bootargs`` device parameter to the NFS device. +This parameter holds a Linux kernel commandline snippet containing a suitable root= +option for booting from exactly that NFS share. + +Example:: + + devinfo nfs0 + ... + linux.bootargs: root=/dev/nfs nfsroot=192.168.23.4:/home/sha/nfsroot/generic-v7,v3,tcp + +The options default to ``v3,tcp`` but can be adjusted before mounting the NFS share with +the ``global.linux.rootnfsopts`` variable diff --git a/fs/nfs.c b/fs/nfs.c index 2738c781d7..5bff54a4dd 100644 --- a/fs/nfs.c +++ b/fs/nfs.c @@ -35,6 +35,7 @@ #include #include #include +#include #include "parseopt.h" @@ -1306,6 +1307,23 @@ static int nfs_stat(struct device_d *dev, const char *filename, struct stat *s) } } +static char *rootnfsopts; + +static void nfs_set_rootarg(struct nfs_priv *npriv, struct fs_device_d *fsdev) +{ + char *str; + const char *ip; + + ip = ip_to_string(npriv->server); + str = asprintf("root=/dev/nfs nfsroot=%s:%s%s%s", + ip, npriv->path, rootnfsopts[0] ? "," : "", + rootnfsopts); + + fsdev_set_linux_rootarg(fsdev, str); + + free(str); +} + static int nfs_probe(struct device_d *dev) { struct fs_device_d *fsdev = dev_to_fs_device(dev); @@ -1369,6 +1387,8 @@ static int nfs_probe(struct device_d *dev) goto err2; } + nfs_set_rootarg(npriv, fsdev); + free(tmp); return 0; @@ -1421,6 +1441,10 @@ static struct fs_driver_d nfs_driver = { static int nfs_init(void) { + rootnfsopts = xstrdup("v3,tcp"); + + globalvar_add_simple_string("linux.rootnfsopts", &rootnfsopts); + return register_fs_driver(&nfs_driver); } coredevice_initcall(nfs_init); -- cgit v1.2.3