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Commit | Line | Data |
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55a97593 TM |
1 | /* |
2 | * linux/fs/nfs/namespace.c | |
3 | * | |
4 | * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> | |
54ceac45 | 5 | * - Modified by David Howells <dhowells@redhat.com> |
55a97593 TM |
6 | * |
7 | * NFS namespace | |
8 | */ | |
9 | ||
ddda8e0a | 10 | #include <linux/module.h> |
55a97593 | 11 | #include <linux/dcache.h> |
5a0e3ad6 | 12 | #include <linux/gfp.h> |
55a97593 TM |
13 | #include <linux/mount.h> |
14 | #include <linux/namei.h> | |
15 | #include <linux/nfs_fs.h> | |
16 | #include <linux/string.h> | |
17 | #include <linux/sunrpc/clnt.h> | |
18 | #include <linux/vfs.h> | |
7ebb9315 | 19 | #include <linux/sunrpc/gss_api.h> |
f7b422b1 | 20 | #include "internal.h" |
55a97593 TM |
21 | |
22 | #define NFSDBG_FACILITY NFSDBG_VFS | |
23 | ||
65f27f38 | 24 | static void nfs_expire_automounts(struct work_struct *work); |
f7b422b1 | 25 | |
a3dab293 | 26 | static LIST_HEAD(nfs_automount_list); |
65f27f38 | 27 | static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); |
51d8fa6a TM |
28 | int nfs_mountpoint_expiry_timeout = 500 * HZ; |
29 | ||
f7b422b1 DH |
30 | /* |
31 | * nfs_path - reconstruct the path given an arbitrary dentry | |
b514f872 | 32 | * @base - used to return pointer to the end of devname part of path |
f7b422b1 DH |
33 | * @dentry - pointer to dentry |
34 | * @buffer - result buffer | |
35 | * @buflen - length of buffer | |
97a54868 | 36 | * @flags - options (see below) |
f7b422b1 | 37 | * |
b514f872 AV |
38 | * Helper function for constructing the server pathname |
39 | * by arbitrary hashed dentry. | |
f7b422b1 DH |
40 | * |
41 | * This is mainly for use in figuring out the path on the | |
b514f872 AV |
42 | * server side when automounting on top of an existing partition |
43 | * and in generating /proc/mounts and friends. | |
97a54868 BH |
44 | * |
45 | * Supported flags: | |
46 | * NFS_PATH_CANONICAL: ensure there is exactly one slash after | |
47 | * the original device (export) name | |
48 | * (if unset, the original name is returned verbatim) | |
f7b422b1 | 49 | */ |
97a54868 BH |
50 | char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen, |
51 | unsigned flags) | |
f7b422b1 | 52 | { |
949854d0 | 53 | char *end; |
f7b422b1 | 54 | int namelen; |
949854d0 | 55 | unsigned seq; |
b514f872 | 56 | const char *base; |
f7b422b1 | 57 | |
949854d0 NP |
58 | rename_retry: |
59 | end = buffer+buflen; | |
f7b422b1 DH |
60 | *--end = '\0'; |
61 | buflen--; | |
949854d0 NP |
62 | |
63 | seq = read_seqbegin(&rename_lock); | |
64 | rcu_read_lock(); | |
b514f872 AV |
65 | while (1) { |
66 | spin_lock(&dentry->d_lock); | |
67 | if (IS_ROOT(dentry)) | |
68 | break; | |
f7b422b1 DH |
69 | namelen = dentry->d_name.len; |
70 | buflen -= namelen + 1; | |
71 | if (buflen < 0) | |
ce510193 | 72 | goto Elong_unlock; |
f7b422b1 DH |
73 | end -= namelen; |
74 | memcpy(end, dentry->d_name.name, namelen); | |
75 | *--end = '/'; | |
b514f872 | 76 | spin_unlock(&dentry->d_lock); |
f7b422b1 DH |
77 | dentry = dentry->d_parent; |
78 | } | |
b514f872 AV |
79 | if (read_seqretry(&rename_lock, seq)) { |
80 | spin_unlock(&dentry->d_lock); | |
81 | rcu_read_unlock(); | |
949854d0 | 82 | goto rename_retry; |
b514f872 | 83 | } |
97a54868 | 84 | if ((flags & NFS_PATH_CANONICAL) && *end != '/') { |
b514f872 AV |
85 | if (--buflen < 0) { |
86 | spin_unlock(&dentry->d_lock); | |
87 | rcu_read_unlock(); | |
0b75b35c | 88 | goto Elong; |
b514f872 | 89 | } |
0b75b35c TM |
90 | *--end = '/'; |
91 | } | |
b514f872 AV |
92 | *p = end; |
93 | base = dentry->d_fsdata; | |
94 | if (!base) { | |
95 | spin_unlock(&dentry->d_lock); | |
96 | rcu_read_unlock(); | |
97 | WARN_ON(1); | |
98 | return end; | |
99 | } | |
f7b422b1 | 100 | namelen = strlen(base); |
86a6c211 | 101 | if (*end == '/') { |
97a54868 BH |
102 | /* Strip off excess slashes in base string */ |
103 | while (namelen > 0 && base[namelen - 1] == '/') | |
104 | namelen--; | |
105 | } | |
f7b422b1 | 106 | buflen -= namelen; |
b514f872 | 107 | if (buflen < 0) { |
1c34092a | 108 | spin_unlock(&dentry->d_lock); |
b514f872 | 109 | rcu_read_unlock(); |
f7b422b1 | 110 | goto Elong; |
b514f872 | 111 | } |
f7b422b1 DH |
112 | end -= namelen; |
113 | memcpy(end, base, namelen); | |
b514f872 AV |
114 | spin_unlock(&dentry->d_lock); |
115 | rcu_read_unlock(); | |
f7b422b1 | 116 | return end; |
ce510193 | 117 | Elong_unlock: |
1c34092a | 118 | spin_unlock(&dentry->d_lock); |
949854d0 NP |
119 | rcu_read_unlock(); |
120 | if (read_seqretry(&rename_lock, seq)) | |
121 | goto rename_retry; | |
f7b422b1 DH |
122 | Elong: |
123 | return ERR_PTR(-ENAMETOOLONG); | |
124 | } | |
89d77c8f | 125 | EXPORT_SYMBOL_GPL(nfs_path); |
f7b422b1 | 126 | |
55a97593 | 127 | /* |
36d43a43 DH |
128 | * nfs_d_automount - Handle crossing a mountpoint on the server |
129 | * @path - The mountpoint | |
55a97593 TM |
130 | * |
131 | * When we encounter a mountpoint on the server, we want to set up | |
132 | * a mountpoint on the client too, to prevent inode numbers from | |
133 | * colliding, and to allow "df" to work properly. | |
134 | * On NFSv4, we also want to allow for the fact that different | |
135 | * filesystems may be migrated to different servers in a failover | |
136 | * situation, and that different filesystems may want to use | |
137 | * different security flavours. | |
138 | */ | |
36d43a43 | 139 | struct vfsmount *nfs_d_automount(struct path *path) |
55a97593 TM |
140 | { |
141 | struct vfsmount *mnt; | |
2b0143b5 | 142 | struct nfs_server *server = NFS_SERVER(d_inode(path->dentry)); |
a4d7f168 TM |
143 | struct nfs_fh *fh = NULL; |
144 | struct nfs_fattr *fattr = NULL; | |
55a97593 | 145 | |
36d43a43 | 146 | if (IS_ROOT(path->dentry)) |
e36d48e9 | 147 | return ERR_PTR(-ESTALE); |
44d5759d | 148 | |
36d43a43 | 149 | mnt = ERR_PTR(-ENOMEM); |
a4d7f168 TM |
150 | fh = nfs_alloc_fhandle(); |
151 | fattr = nfs_alloc_fattr(); | |
152 | if (fh == NULL || fattr == NULL) | |
36d43a43 | 153 | goto out; |
a4d7f168 | 154 | |
281cad46 | 155 | mnt = server->nfs_client->rpc_ops->submount(server, path->dentry, fh, fattr); |
55a97593 | 156 | if (IS_ERR(mnt)) |
36d43a43 | 157 | goto out; |
55a97593 | 158 | |
ea5b778a DH |
159 | mntget(mnt); /* prevent immediate expiration */ |
160 | mnt_set_expiry(mnt, &nfs_automount_list); | |
161 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
36d43a43 | 162 | |
55a97593 | 163 | out: |
a4d7f168 TM |
164 | nfs_free_fattr(fattr); |
165 | nfs_free_fhandle(fh); | |
36d43a43 | 166 | return mnt; |
55a97593 TM |
167 | } |
168 | ||
ab225417 | 169 | static int |
a528d35e DH |
170 | nfs_namespace_getattr(const struct path *path, struct kstat *stat, |
171 | u32 request_mask, unsigned int query_flags) | |
ab225417 | 172 | { |
a528d35e DH |
173 | if (NFS_FH(d_inode(path->dentry))->size != 0) |
174 | return nfs_getattr(path, stat, request_mask, query_flags); | |
175 | generic_fillattr(d_inode(path->dentry), stat); | |
ab225417 TM |
176 | return 0; |
177 | } | |
178 | ||
179 | static int | |
180 | nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr) | |
181 | { | |
2b0143b5 | 182 | if (NFS_FH(d_inode(dentry))->size != 0) |
ab225417 TM |
183 | return nfs_setattr(dentry, attr); |
184 | return -EACCES; | |
185 | } | |
186 | ||
92e1d5be | 187 | const struct inode_operations nfs_mountpoint_inode_operations = { |
55a97593 | 188 | .getattr = nfs_getattr, |
ab225417 | 189 | .setattr = nfs_setattr, |
55a97593 | 190 | }; |
51d8fa6a | 191 | |
92e1d5be | 192 | const struct inode_operations nfs_referral_inode_operations = { |
ab225417 TM |
193 | .getattr = nfs_namespace_getattr, |
194 | .setattr = nfs_namespace_setattr, | |
6b97fd3d MN |
195 | }; |
196 | ||
65f27f38 | 197 | static void nfs_expire_automounts(struct work_struct *work) |
51d8fa6a | 198 | { |
65f27f38 | 199 | struct list_head *list = &nfs_automount_list; |
51d8fa6a TM |
200 | |
201 | mark_mounts_for_expiry(list); | |
202 | if (!list_empty(list)) | |
203 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
204 | } | |
205 | ||
206 | void nfs_release_automount_timer(void) | |
207 | { | |
3d39c691 | 208 | if (list_empty(&nfs_automount_list)) |
560aef74 | 209 | cancel_delayed_work(&nfs_automount_task); |
51d8fa6a | 210 | } |
f7b422b1 DH |
211 | |
212 | /* | |
213 | * Clone a mountpoint of the appropriate type | |
214 | */ | |
509de811 DH |
215 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
216 | const char *devname, | |
f7b422b1 DH |
217 | struct nfs_clone_mount *mountdata) |
218 | { | |
93faccbb | 219 | return vfs_submount(mountdata->dentry, &nfs_xdev_fs_type, devname, mountdata); |
f7b422b1 DH |
220 | } |
221 | ||
222 | /** | |
223 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary | |
302fad7b TM |
224 | * @dentry: parent directory |
225 | * @fh: filehandle for new root dentry | |
226 | * @fattr: attributes for new root inode | |
227 | * @authflavor: security flavor to use when performing the mount | |
f7b422b1 DH |
228 | * |
229 | */ | |
281cad46 BS |
230 | struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh, |
231 | struct nfs_fattr *fattr, rpc_authflavor_t authflavor) | |
f7b422b1 DH |
232 | { |
233 | struct nfs_clone_mount mountdata = { | |
f8ad9c4b | 234 | .sb = dentry->d_sb, |
f7b422b1 DH |
235 | .dentry = dentry, |
236 | .fh = fh, | |
237 | .fattr = fattr, | |
7ebb9315 | 238 | .authflavor = authflavor, |
f7b422b1 | 239 | }; |
e36d48e9 | 240 | struct vfsmount *mnt; |
f7b422b1 DH |
241 | char *page = (char *) __get_free_page(GFP_USER); |
242 | char *devname; | |
243 | ||
f7b422b1 | 244 | if (page == NULL) |
e36d48e9 AS |
245 | return ERR_PTR(-ENOMEM); |
246 | ||
b514f872 | 247 | devname = nfs_devname(dentry, page, PAGE_SIZE); |
f7b422b1 | 248 | if (IS_ERR(devname)) |
fe3b81b4 | 249 | mnt = ERR_CAST(devname); |
e36d48e9 AS |
250 | else |
251 | mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata); | |
54ceac45 | 252 | |
e36d48e9 | 253 | free_page((unsigned long)page); |
f7b422b1 DH |
254 | return mnt; |
255 | } | |
89d77c8f | 256 | EXPORT_SYMBOL_GPL(nfs_do_submount); |
281cad46 BS |
257 | |
258 | struct vfsmount *nfs_submount(struct nfs_server *server, struct dentry *dentry, | |
259 | struct nfs_fh *fh, struct nfs_fattr *fattr) | |
260 | { | |
261 | int err; | |
262 | struct dentry *parent = dget_parent(dentry); | |
263 | ||
264 | /* Look it up again to get its attributes */ | |
2b0143b5 | 265 | err = server->nfs_client->rpc_ops->lookup(d_inode(parent), &dentry->d_name, fh, fattr, NULL); |
281cad46 BS |
266 | dput(parent); |
267 | if (err != 0) | |
268 | return ERR_PTR(err); | |
269 | ||
270 | return nfs_do_submount(dentry, fh, fattr, server->client->cl_auth->au_flavor); | |
271 | } | |
ddda8e0a | 272 | EXPORT_SYMBOL_GPL(nfs_submount); |