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DEFINITIONS
This source file includes following definitions.
- nfs4_pathname_string
- nfs4_path
- nfs4_validate_fspath
- valid_ipaddr4
- nfs_follow_referral
- nfs_do_refmount
/*
* linux/fs/nfs/nfs4namespace.c
*
* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
* - Modified by David Howells <dhowells@redhat.com>
*
* NFSv4 namespace
*/
#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/nfs_fs.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"
#define NFSDBG_FACILITY NFSDBG_VFS
/*
* Check if fs_root is valid
*/
static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
char *buffer, ssize_t buflen)
{
char *end = buffer + buflen;
int n;
*--end = '\0';
buflen--;
n = pathname->ncomponents;
while (--n >= 0) {
const struct nfs4_string *component = &pathname->components[n];
buflen -= component->len + 1;
if (buflen < 0)
goto Elong;
end -= component->len;
memcpy(end, component->data, component->len);
*--end = '/';
}
return end;
Elong:
return ERR_PTR(-ENAMETOOLONG);
}
/*
* Determine the mount path as a string
*/
static char *nfs4_path(const struct vfsmount *mnt_parent,
const struct dentry *dentry,
char *buffer, ssize_t buflen)
{
const char *srvpath;
srvpath = strchr(mnt_parent->mnt_devname, ':');
if (srvpath)
srvpath++;
else
srvpath = mnt_parent->mnt_devname;
return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
}
/*
* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
* believe to be the server path to this dentry
*/
static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
const struct dentry *dentry,
const struct nfs4_fs_locations *locations,
char *page, char *page2)
{
const char *path, *fs_path;
path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
if (IS_ERR(path))
return PTR_ERR(path);
fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
if (IS_ERR(fs_path))
return PTR_ERR(fs_path);
if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
dprintk("%s: path %s does not begin with fsroot %s\n",
__func__, path, fs_path);
return -ENOENT;
}
return 0;
}
/*
* Check if the string represents a "valid" IPv4 address
*/
static inline int valid_ipaddr4(const char *buf)
{
int rc, count, in[4];
rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
if (rc != 4)
return -EINVAL;
for (count = 0; count < 4; count++) {
if (in[count] > 255)
return -EINVAL;
}
return 0;
}
/**
* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
* @mnt_parent - mountpoint of parent directory
* @dentry - parent directory
* @locations - array of NFSv4 server location information
*
*/
static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
const struct dentry *dentry,
const struct nfs4_fs_locations *locations)
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
struct nfs_clone_mount mountdata = {
.sb = mnt_parent->mnt_sb,
.dentry = dentry,
.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
};
char *page = NULL, *page2 = NULL;
unsigned int s;
int loc, error;
if (locations == NULL || locations->nlocations <= 0)
goto out;
dprintk("%s: referral at %s/%s\n", __func__,
dentry->d_parent->d_name.name, dentry->d_name.name);
page = (char *) __get_free_page(GFP_USER);
if (!page)
goto out;
page2 = (char *) __get_free_page(GFP_USER);
if (!page2)
goto out;
/* Ensure fs path is a prefix of current dentry path */
error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
if (error < 0) {
mnt = ERR_PTR(error);
goto out;
}
loc = 0;
while (loc < locations->nlocations && IS_ERR(mnt)) {
const struct nfs4_fs_location *location = &locations->locations[loc];
char *mnt_path;
if (location == NULL || location->nservers <= 0 ||
location->rootpath.ncomponents == 0) {
loc++;
continue;
}
mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
if (IS_ERR(mnt_path)) {
loc++;
continue;
}
mountdata.mnt_path = mnt_path;
s = 0;
while (s < location->nservers) {
struct sockaddr_in addr = {
.sin_family = AF_INET,
.sin_port = htons(NFS_PORT),
};
if (location->servers[s].len <= 0 ||
valid_ipaddr4(location->servers[s].data) < 0) {
s++;
continue;
}
mountdata.hostname = location->servers[s].data;
addr.sin_addr.s_addr = in_aton(mountdata.hostname),
mountdata.addr = (struct sockaddr *)&addr;
mountdata.addrlen = sizeof(addr);
snprintf(page, PAGE_SIZE, "%s:%s",
mountdata.hostname,
mountdata.mnt_path);
mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, &mountdata);
if (!IS_ERR(mnt)) {
break;
}
s++;
}
loc++;
}
out:
free_page((unsigned long) page);
free_page((unsigned long) page2);
dprintk("%s: done\n", __func__);
return mnt;
}
/*
* nfs_do_refmount - handle crossing a referral on server
* @dentry - dentry of referral
* @nd - nameidata info
*
*/
struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
{
struct vfsmount *mnt = ERR_PTR(-ENOMEM);
struct dentry *parent;
struct nfs4_fs_locations *fs_locations = NULL;
struct page *page;
int err;
/* BUG_ON(IS_ROOT(dentry)); */
dprintk("%s: enter\n", __func__);
page = alloc_page(GFP_KERNEL);
if (page == NULL)
goto out;
fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
if (fs_locations == NULL)
goto out_free;
/* Get locations */
mnt = ERR_PTR(-ENOENT);
parent = dget_parent(dentry);
dprintk("%s: getting locations for %s/%s\n",
__func__, parent->d_name.name, dentry->d_name.name);
err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
dput(parent);
if (err != 0 ||
fs_locations->nlocations <= 0 ||
fs_locations->fs_path.ncomponents <= 0)
goto out_free;
mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
out_free:
__free_page(page);
kfree(fs_locations);
out:
dprintk("%s: done\n", __func__);
return mnt;
}