- 根目录:
- fs
- nfs
- nfs4namespace.c
/*
* 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/nfs_mount.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"
#include "dns_resolve.h"
#define NFSDBG_FACILITY NFSDBG_VFS
/*
* Convert the NFSv4 pathname components into a standard posix path.
*
* Note that the resulting string will be placed at the end of the buffer
*/
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);
}
/*
* return the path component of "<server>:<path>"
* nfspath - the "<server>:<path>" string
* end - one past the last char that could contain "<server>:"
* returns NULL on failure
*/
static char *nfs_path_component(const char *nfspath, const char *end)
{
char *p;
if (*nfspath == '[') {
/* parse [] escaped IPv6 addrs */
p = strchr(nfspath, ']');
if (p != NULL && ++p < end && *p == ':')
return p + 1;
} else {
/* otherwise split on first colon */
p = strchr(nfspath, ':');
if (p != NULL && p < end)
return p + 1;
}
return NULL;
}
/*
* Determine the mount path as a string
*/
static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
{
char *limit;
char *path = nfs_path(&limit, dentry, buffer, buflen,
NFS_PATH_CANONICAL);
if (!IS_ERR(path)) {
char *path_component = nfs_path_component(path, limit);
if (path_component)
return path_component;
}
return path;
}
/*
* 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(struct dentry *dentry,
const struct nfs4_fs_locations *locations,
char *page, char *page2)
{
const char *path, *fs_path;
path = nfs4_path(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;
}
static size_t nfs_parse_server_name(char *string, size_t len,
struct sockaddr *sa, size_t salen, struct net *net)
{
ssize_t ret;
ret = rpc_pton(net, string, len, sa, salen);
if (ret == 0) {
ret = nfs_dns_resolve_name(net, string, len, sa, salen);
if (ret < 0)
ret = 0;
}
return ret;
}
/**
* nfs_find_best_sec - Find a security mechanism supported locally
* @server: NFS server struct
* @flavors: List of security tuples returned by SECINFO procedure
*
* Return an rpc client that uses the first security mechanism in
* "flavors" that is locally supported. The "flavors" array
* is searched in the order returned from the server, per RFC 3530
* recommendation and each flavor is checked for membership in the
* sec= mount option list if it exists.
*
* Return -EPERM if no matching flavor is found in the array.
*
* Please call rpc_shutdown_client() when you are done with this rpc client.
*
*/
static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
struct nfs_server *server,
struct nfs4_secinfo_flavors *flavors)
{
rpc_authflavor_t pflavor;
struct nfs4_secinfo4 *secinfo;
unsigned int i;
for (i = 0; i < flavors->num_flavors; i++) {
secinfo = &flavors->flavors[i];
switch (secinfo->flavor) {
case RPC_AUTH_NULL:
case RPC_AUTH_UNIX:
case RPC_AUTH_GSS:
pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
&secinfo->flavor_info);
/* does the pseudoflavor match a sec= mount opt? */
if (pflavor != RPC_AUTH_MAXFLAVOR &&
nfs_auth_info_match(&server->auth_info, pflavor)) {
struct rpc_clnt *new;
struct rpc_cred *cred;
/* Cloning creates an rpc_auth for the flavor */
new = rpc_clone_client_set_auth(clnt, pflavor);
if (IS_ERR(new))
continue;
/**
* Check that the user actually can use the
* flavor. This is mostly for RPC_AUTH_GSS
* where cr_init obtains a gss context
*/
cred = rpcauth_lookupcred(new->cl_auth, 0);
if (IS_ERR(cred)) {
rpc_shutdown_client(new);
continue;
}
put_rpccred(cred);
return new;
}
}
}
return ERR_PTR(-EPERM);
}
/**
* nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
* return an rpc_clnt that uses the best available security flavor with
* respect to the secinfo flavor list and the sec= mount options.
*
* @clnt: RPC client to clone
* @inode: directory inode
* @name: lookup name
*
* Please call rpc_shutdown_client() when you are done with this rpc client.
*/
struct rpc_clnt *
nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
struct qstr *name)
{
struct page *page;
struct nfs4_secinfo_flavors *flavors;
struct rpc_clnt *new;
int err;
page = alloc_page(GFP_KERNEL);
if (!page)
return ERR_PTR(-ENOMEM);
flavors = page_address(page);
err = nfs4_proc_secinfo(inode, name, flavors);
if (err < 0) {
new = ERR_PTR(err);
goto out;
}
new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
out:
put_page(page);
return new;
}
static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
char *page, char *page2,
const struct nfs4_fs_location *location)
{
const size_t addr_bufsize = sizeof(struct sockaddr_storage);
struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
struct vfsmount *mnt = ERR_PTR(-ENOENT);
char *mnt_path;
unsigned int maxbuflen;
unsigned int s;
mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
if (IS_ERR(mnt_path))
return ERR_CAST(mnt_path);
mountdata->mnt_path = mnt_path;
maxbuflen = mnt_path - 1 - page2;
mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
if (mountdata->addr == NULL)
return ERR_PTR(-ENOMEM);
for (s = 0; s < location->nservers; s++) {
const struct nfs4_string *buf = &location->servers[s];
if (buf->len <= 0 || buf->len >= maxbuflen)
continue;
if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
continue;
mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
mountdata->addr, addr_bufsize, net);
if (mountdata->addrlen == 0)
continue;
rpc_set_port(mountdata->addr, NFS_PORT);
memcpy(page2, buf->data, buf->len);
page2[buf->len] = '\0';
mountdata->hostname = page2;
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;
}
kfree(mountdata->addr);
return mnt;
}
/**
* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
* @dentry - parent directory
* @locations - array of NFSv4 server location information
*
*/
static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
const struct nfs4_fs_locations *locations)
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
struct nfs_clone_mount mountdata = {
.sb = dentry->d_sb,
.dentry = dentry,
.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
};
char *page = NULL, *page2 = NULL;
int loc, error;
if (locations == NULL || locations->nlocations <= 0)
goto out;
dprintk("%s: referral at %pd2\n", __func__, dentry);
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(dentry, locations, page, page2);
if (error < 0) {
mnt = ERR_PTR(error);
goto out;
}
for (loc = 0; loc < locations->nlocations; loc++) {
const struct nfs4_fs_location *location = &locations->locations[loc];
if (location == NULL || location->nservers <= 0 ||
location->rootpath.ncomponents == 0)
continue;
mnt = try_location(&mountdata, page, page2, location);
if (!IS_ERR(mnt))
break;
}
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
*
*/
static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, 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 %pd2\n",
__func__, dentry);
err = nfs4_proc_fs_locations(client, 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(dentry, fs_locations);
out_free:
__free_page(page);
kfree(fs_locations);
out:
dprintk("%s: done\n", __func__);
return mnt;
}
struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
struct nfs_fh *fh, struct nfs_fattr *fattr)
{
rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
struct dentry *parent = dget_parent(dentry);
struct inode *dir = parent->d_inode;
struct qstr *name = &dentry->d_name;
struct rpc_clnt *client;
struct vfsmount *mnt;
/* Look it up again to get its attributes and sec flavor */
client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
dput(parent);
if (IS_ERR(client))
return ERR_CAST(client);
if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
mnt = nfs_do_refmount(client, dentry);
goto out;
}
if (client->cl_auth->au_flavor != flavor)
flavor = client->cl_auth->au_flavor;
mnt = nfs_do_submount(dentry, fh, fattr, flavor);
out:
rpc_shutdown_client(client);
return mnt;
}
/*
* Try one location from the fs_locations array.
*
* Returns zero on success, or a negative errno value.
*/
static int nfs4_try_replacing_one_location(struct nfs_server *server,
char *page, char *page2,
const struct nfs4_fs_location *location)
{
const size_t addr_bufsize = sizeof(struct sockaddr_storage);
struct net *net = rpc_net_ns(server->client);
struct sockaddr *sap;
unsigned int s;
size_t salen;
int error;
sap = kmalloc(addr_bufsize, GFP_KERNEL);
if (sap == NULL)
return -ENOMEM;
error = -ENOENT;
for (s = 0; s < location->nservers; s++) {
const struct nfs4_string *buf = &location->servers[s];
char *hostname;
if (buf->len <= 0 || buf->len > PAGE_SIZE)
continue;
if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
continue;
salen = nfs_parse_server_name(buf->data, buf->len,
sap, addr_bufsize, net);
if (salen == 0)
continue;
rpc_set_port(sap, NFS_PORT);
error = -ENOMEM;
hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
if (hostname == NULL)
break;
error = nfs4_update_server(server, hostname, sap, salen, net);
kfree(hostname);
if (error == 0)
break;
}
kfree(sap);
return error;
}
/**
* nfs4_replace_transport - set up transport to destination server
*
* @server: export being migrated
* @locations: fs_locations array
*
* Returns zero on success, or a negative errno value.
*
* The client tries all the entries in the "locations" array, in the
* order returned by the server, until one works or the end of the
* array is reached.
*/
int nfs4_replace_transport(struct nfs_server *server,
const struct nfs4_fs_locations *locations)
{
char *page = NULL, *page2 = NULL;
int loc, error;
error = -ENOENT;
if (locations == NULL || locations->nlocations <= 0)
goto out;
error = -ENOMEM;
page = (char *) __get_free_page(GFP_USER);
if (!page)
goto out;
page2 = (char *) __get_free_page(GFP_USER);
if (!page2)
goto out;
for (loc = 0; loc < locations->nlocations; loc++) {
const struct nfs4_fs_location *location =
&locations->locations[loc];
if (location == NULL || location->nservers <= 0 ||
location->rootpath.ncomponents == 0)
continue;
error = nfs4_try_replacing_one_location(server, page,
page2, location);
if (error == 0)
break;
}
out:
free_page((unsigned long)page);
free_page((unsigned long)page2);
return error;
}