2 * linux/fs/nfs/nfs4namespace.c
4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
5 * - Modified by David Howells <dhowells@redhat.com>
10 #include <linux/dcache.h>
11 #include <linux/mount.h>
12 #include <linux/namei.h>
13 #include <linux/nfs_fs.h>
14 #include <linux/slab.h>
15 #include <linux/string.h>
16 #include <linux/sunrpc/clnt.h>
17 #include <linux/vfs.h>
18 #include <linux/inet.h>
21 #include "dns_resolve.h"
23 #define NFSDBG_FACILITY NFSDBG_VFS
26 * Convert the NFSv4 pathname components into a standard posix path.
28 * Note that the resulting string will be placed at the end of the buffer
30 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
31 char *buffer, ssize_t buflen)
33 char *end = buffer + buflen;
39 n = pathname->ncomponents;
41 const struct nfs4_string *component = &pathname->components[n];
42 buflen -= component->len + 1;
45 end -= component->len;
46 memcpy(end, component->data, component->len);
51 return ERR_PTR(-ENAMETOOLONG);
55 * Determine the mount path as a string
57 static char *nfs4_path(const struct vfsmount *mnt_parent,
58 const struct dentry *dentry,
59 char *buffer, ssize_t buflen)
63 srvpath = strchr(mnt_parent->mnt_devname, ':');
67 srvpath = mnt_parent->mnt_devname;
69 return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
73 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
74 * believe to be the server path to this dentry
76 static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
77 const struct dentry *dentry,
78 const struct nfs4_fs_locations *locations,
79 char *page, char *page2)
81 const char *path, *fs_path;
83 path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
87 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
89 return PTR_ERR(fs_path);
91 if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
92 dprintk("%s: path %s does not begin with fsroot %s\n",
93 __func__, path, fs_path);
100 static size_t nfs_parse_server_name(char *string, size_t len,
101 struct sockaddr *sa, size_t salen)
105 ret = rpc_pton(string, len, sa, salen);
107 ret = nfs_dns_resolve_name(string, len, sa, salen);
114 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
115 char *page, char *page2,
116 const struct nfs4_fs_location *location)
118 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
119 struct vfsmount *mnt = ERR_PTR(-ENOENT);
121 unsigned int maxbuflen;
124 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
125 if (IS_ERR(mnt_path))
126 return ERR_CAST(mnt_path);
127 mountdata->mnt_path = mnt_path;
128 maxbuflen = mnt_path - 1 - page2;
130 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
131 if (mountdata->addr == NULL)
132 return ERR_PTR(-ENOMEM);
134 for (s = 0; s < location->nservers; s++) {
135 const struct nfs4_string *buf = &location->servers[s];
137 if (buf->len <= 0 || buf->len >= maxbuflen)
140 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
143 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
144 mountdata->addr, addr_bufsize);
145 if (mountdata->addrlen == 0)
148 rpc_set_port(mountdata->addr, NFS_PORT);
150 memcpy(page2, buf->data, buf->len);
151 page2[buf->len] = '\0';
152 mountdata->hostname = page2;
154 snprintf(page, PAGE_SIZE, "%s:%s",
156 mountdata->mnt_path);
158 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
162 kfree(mountdata->addr);
167 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
168 * @mnt_parent - mountpoint of parent directory
169 * @dentry - parent directory
170 * @locations - array of NFSv4 server location information
173 static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
174 const struct dentry *dentry,
175 const struct nfs4_fs_locations *locations)
177 struct vfsmount *mnt = ERR_PTR(-ENOENT);
178 struct nfs_clone_mount mountdata = {
179 .sb = mnt_parent->mnt_sb,
181 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
183 char *page = NULL, *page2 = NULL;
186 if (locations == NULL || locations->nlocations <= 0)
189 dprintk("%s: referral at %s/%s\n", __func__,
190 dentry->d_parent->d_name.name, dentry->d_name.name);
192 page = (char *) __get_free_page(GFP_USER);
196 page2 = (char *) __get_free_page(GFP_USER);
200 /* Ensure fs path is a prefix of current dentry path */
201 error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
203 mnt = ERR_PTR(error);
207 for (loc = 0; loc < locations->nlocations; loc++) {
208 const struct nfs4_fs_location *location = &locations->locations[loc];
210 if (location == NULL || location->nservers <= 0 ||
211 location->rootpath.ncomponents == 0)
214 mnt = try_location(&mountdata, page, page2, location);
220 free_page((unsigned long) page);
221 free_page((unsigned long) page2);
222 dprintk("%s: done\n", __func__);
227 * nfs_do_refmount - handle crossing a referral on server
228 * @mnt_parent - mountpoint of referral
229 * @dentry - dentry of referral
232 struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
234 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
235 struct dentry *parent;
236 struct nfs4_fs_locations *fs_locations = NULL;
240 /* BUG_ON(IS_ROOT(dentry)); */
241 dprintk("%s: enter\n", __func__);
243 page = alloc_page(GFP_KERNEL);
247 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
248 if (fs_locations == NULL)
252 mnt = ERR_PTR(-ENOENT);
254 parent = dget_parent(dentry);
255 dprintk("%s: getting locations for %s/%s\n",
256 __func__, parent->d_name.name, dentry->d_name.name);
258 err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
261 fs_locations->nlocations <= 0 ||
262 fs_locations->fs_path.ncomponents <= 0)
265 mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
270 dprintk("%s: done\n", __func__);