Merge branch 'linus' into core/futexes
[sfrench/cifs-2.6.git] / fs / nfs / nfs4namespace.c
1 /*
2  * linux/fs/nfs/nfs4namespace.c
3  *
4  * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
5  * - Modified by David Howells <dhowells@redhat.com>
6  *
7  * NFSv4 namespace
8  */
9
10 #include <linux/dcache.h>
11 #include <linux/mount.h>
12 #include <linux/namei.h>
13 #include <linux/nfs_fs.h>
14 #include <linux/string.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/vfs.h>
17 #include <linux/inet.h>
18 #include "internal.h"
19 #include "nfs4_fs.h"
20
21 #define NFSDBG_FACILITY         NFSDBG_VFS
22
23 /*
24  * Check if fs_root is valid
25  */
26 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
27                                          char *buffer, ssize_t buflen)
28 {
29         char *end = buffer + buflen;
30         int n;
31
32         *--end = '\0';
33         buflen--;
34
35         n = pathname->ncomponents;
36         while (--n >= 0) {
37                 const struct nfs4_string *component = &pathname->components[n];
38                 buflen -= component->len + 1;
39                 if (buflen < 0)
40                         goto Elong;
41                 end -= component->len;
42                 memcpy(end, component->data, component->len);
43                 *--end = '/';
44         }
45         return end;
46 Elong:
47         return ERR_PTR(-ENAMETOOLONG);
48 }
49
50 /*
51  * Determine the mount path as a string
52  */
53 static char *nfs4_path(const struct vfsmount *mnt_parent,
54                        const struct dentry *dentry,
55                        char *buffer, ssize_t buflen)
56 {
57         const char *srvpath;
58
59         srvpath = strchr(mnt_parent->mnt_devname, ':');
60         if (srvpath)
61                 srvpath++;
62         else
63                 srvpath = mnt_parent->mnt_devname;
64
65         return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
66 }
67
68 /*
69  * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
70  * believe to be the server path to this dentry
71  */
72 static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
73                                 const struct dentry *dentry,
74                                 const struct nfs4_fs_locations *locations,
75                                 char *page, char *page2)
76 {
77         const char *path, *fs_path;
78
79         path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
80         if (IS_ERR(path))
81                 return PTR_ERR(path);
82
83         fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
84         if (IS_ERR(fs_path))
85                 return PTR_ERR(fs_path);
86
87         if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
88                 dprintk("%s: path %s does not begin with fsroot %s\n",
89                         __func__, path, fs_path);
90                 return -ENOENT;
91         }
92
93         return 0;
94 }
95
96 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
97                                      char *page, char *page2,
98                                      const struct nfs4_fs_location *location)
99 {
100         struct vfsmount *mnt = ERR_PTR(-ENOENT);
101         char *mnt_path;
102         int page2len;
103         unsigned int s;
104
105         mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
106         if (IS_ERR(mnt_path))
107                 return mnt;
108         mountdata->mnt_path = mnt_path;
109         page2 += strlen(mnt_path) + 1;
110         page2len = PAGE_SIZE - strlen(mnt_path) - 1;
111
112         for (s = 0; s < location->nservers; s++) {
113                 const struct nfs4_string *buf = &location->servers[s];
114                 struct sockaddr_storage addr;
115
116                 if (buf->len <= 0 || buf->len >= PAGE_SIZE)
117                         continue;
118
119                 mountdata->addr = (struct sockaddr *)&addr;
120
121                 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
122                         continue;
123                 nfs_parse_ip_address(buf->data, buf->len,
124                                 mountdata->addr, &mountdata->addrlen);
125                 if (mountdata->addr->sa_family == AF_UNSPEC)
126                         continue;
127                 nfs_set_port(mountdata->addr, NFS_PORT);
128
129                 strncpy(page2, buf->data, page2len);
130                 page2[page2len] = '\0';
131                 mountdata->hostname = page2;
132
133                 snprintf(page, PAGE_SIZE, "%s:%s",
134                                 mountdata->hostname,
135                                 mountdata->mnt_path);
136
137                 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
138                 if (!IS_ERR(mnt))
139                         break;
140         }
141         return mnt;
142 }
143
144 /**
145  * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
146  * @mnt_parent - mountpoint of parent directory
147  * @dentry - parent directory
148  * @locations - array of NFSv4 server location information
149  *
150  */
151 static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
152                                             const struct dentry *dentry,
153                                             const struct nfs4_fs_locations *locations)
154 {
155         struct vfsmount *mnt = ERR_PTR(-ENOENT);
156         struct nfs_clone_mount mountdata = {
157                 .sb = mnt_parent->mnt_sb,
158                 .dentry = dentry,
159                 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
160         };
161         char *page = NULL, *page2 = NULL;
162         int loc, error;
163
164         if (locations == NULL || locations->nlocations <= 0)
165                 goto out;
166
167         dprintk("%s: referral at %s/%s\n", __func__,
168                 dentry->d_parent->d_name.name, dentry->d_name.name);
169
170         page = (char *) __get_free_page(GFP_USER);
171         if (!page)
172                 goto out;
173
174         page2 = (char *) __get_free_page(GFP_USER);
175         if (!page2)
176                 goto out;
177
178         /* Ensure fs path is a prefix of current dentry path */
179         error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
180         if (error < 0) {
181                 mnt = ERR_PTR(error);
182                 goto out;
183         }
184
185         for (loc = 0; loc < locations->nlocations; loc++) {
186                 const struct nfs4_fs_location *location = &locations->locations[loc];
187
188                 if (location == NULL || location->nservers <= 0 ||
189                     location->rootpath.ncomponents == 0)
190                         continue;
191
192                 mnt = try_location(&mountdata, page, page2, location);
193                 if (!IS_ERR(mnt))
194                         break;
195         }
196
197 out:
198         free_page((unsigned long) page);
199         free_page((unsigned long) page2);
200         dprintk("%s: done\n", __func__);
201         return mnt;
202 }
203
204 /*
205  * nfs_do_refmount - handle crossing a referral on server
206  * @dentry - dentry of referral
207  * @nd - nameidata info
208  *
209  */
210 struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
211 {
212         struct vfsmount *mnt = ERR_PTR(-ENOMEM);
213         struct dentry *parent;
214         struct nfs4_fs_locations *fs_locations = NULL;
215         struct page *page;
216         int err;
217
218         /* BUG_ON(IS_ROOT(dentry)); */
219         dprintk("%s: enter\n", __func__);
220
221         page = alloc_page(GFP_KERNEL);
222         if (page == NULL)
223                 goto out;
224
225         fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
226         if (fs_locations == NULL)
227                 goto out_free;
228
229         /* Get locations */
230         mnt = ERR_PTR(-ENOENT);
231
232         parent = dget_parent(dentry);
233         dprintk("%s: getting locations for %s/%s\n",
234                 __func__, parent->d_name.name, dentry->d_name.name);
235
236         err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
237         dput(parent);
238         if (err != 0 ||
239             fs_locations->nlocations <= 0 ||
240             fs_locations->fs_path.ncomponents <= 0)
241                 goto out_free;
242
243         mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
244 out_free:
245         __free_page(page);
246         kfree(fs_locations);
247 out:
248         dprintk("%s: done\n", __func__);
249         return mnt;
250 }