Commit | Line | Data |
---|---|---|
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 | ||
55a97593 | 10 | #include <linux/dcache.h> |
5a0e3ad6 | 11 | #include <linux/gfp.h> |
55a97593 TM |
12 | #include <linux/mount.h> |
13 | #include <linux/namei.h> | |
14 | #include <linux/nfs_fs.h> | |
15 | #include <linux/string.h> | |
16 | #include <linux/sunrpc/clnt.h> | |
17 | #include <linux/vfs.h> | |
f7b422b1 | 18 | #include "internal.h" |
55a97593 TM |
19 | |
20 | #define NFSDBG_FACILITY NFSDBG_VFS | |
21 | ||
65f27f38 | 22 | static void nfs_expire_automounts(struct work_struct *work); |
f7b422b1 | 23 | |
a3dab293 | 24 | static LIST_HEAD(nfs_automount_list); |
65f27f38 | 25 | static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); |
51d8fa6a TM |
26 | int nfs_mountpoint_expiry_timeout = 500 * HZ; |
27 | ||
f8ad9c4b | 28 | static struct vfsmount *nfs_do_submount(struct dentry *dentry, |
66f37509 AB |
29 | struct nfs_fh *fh, |
30 | struct nfs_fattr *fattr); | |
31 | ||
f7b422b1 DH |
32 | /* |
33 | * nfs_path - reconstruct the path given an arbitrary dentry | |
b514f872 | 34 | * @base - used to return pointer to the end of devname part of path |
f7b422b1 DH |
35 | * @dentry - pointer to dentry |
36 | * @buffer - result buffer | |
37 | * @buflen - length of buffer | |
38 | * | |
b514f872 AV |
39 | * Helper function for constructing the server pathname |
40 | * by arbitrary hashed dentry. | |
f7b422b1 DH |
41 | * |
42 | * This is mainly for use in figuring out the path on the | |
b514f872 AV |
43 | * server side when automounting on top of an existing partition |
44 | * and in generating /proc/mounts and friends. | |
f7b422b1 | 45 | */ |
b514f872 | 46 | char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen) |
f7b422b1 | 47 | { |
949854d0 | 48 | char *end; |
f7b422b1 | 49 | int namelen; |
949854d0 | 50 | unsigned seq; |
b514f872 | 51 | const char *base; |
f7b422b1 | 52 | |
949854d0 NP |
53 | rename_retry: |
54 | end = buffer+buflen; | |
f7b422b1 DH |
55 | *--end = '\0'; |
56 | buflen--; | |
949854d0 NP |
57 | |
58 | seq = read_seqbegin(&rename_lock); | |
59 | rcu_read_lock(); | |
b514f872 AV |
60 | while (1) { |
61 | spin_lock(&dentry->d_lock); | |
62 | if (IS_ROOT(dentry)) | |
63 | break; | |
f7b422b1 DH |
64 | namelen = dentry->d_name.len; |
65 | buflen -= namelen + 1; | |
66 | if (buflen < 0) | |
ce510193 | 67 | goto Elong_unlock; |
f7b422b1 DH |
68 | end -= namelen; |
69 | memcpy(end, dentry->d_name.name, namelen); | |
70 | *--end = '/'; | |
b514f872 | 71 | spin_unlock(&dentry->d_lock); |
f7b422b1 DH |
72 | dentry = dentry->d_parent; |
73 | } | |
b514f872 AV |
74 | if (read_seqretry(&rename_lock, seq)) { |
75 | spin_unlock(&dentry->d_lock); | |
76 | rcu_read_unlock(); | |
949854d0 | 77 | goto rename_retry; |
b514f872 | 78 | } |
0b75b35c | 79 | if (*end != '/') { |
b514f872 AV |
80 | if (--buflen < 0) { |
81 | spin_unlock(&dentry->d_lock); | |
82 | rcu_read_unlock(); | |
0b75b35c | 83 | goto Elong; |
b514f872 | 84 | } |
0b75b35c TM |
85 | *--end = '/'; |
86 | } | |
b514f872 AV |
87 | *p = end; |
88 | base = dentry->d_fsdata; | |
89 | if (!base) { | |
90 | spin_unlock(&dentry->d_lock); | |
91 | rcu_read_unlock(); | |
92 | WARN_ON(1); | |
93 | return end; | |
94 | } | |
f7b422b1 DH |
95 | namelen = strlen(base); |
96 | /* Strip off excess slashes in base string */ | |
97 | while (namelen > 0 && base[namelen - 1] == '/') | |
98 | namelen--; | |
99 | buflen -= namelen; | |
b514f872 AV |
100 | if (buflen < 0) { |
101 | spin_lock(&dentry->d_lock); | |
102 | rcu_read_unlock(); | |
f7b422b1 | 103 | goto Elong; |
b514f872 | 104 | } |
f7b422b1 DH |
105 | end -= namelen; |
106 | memcpy(end, base, namelen); | |
b514f872 AV |
107 | spin_unlock(&dentry->d_lock); |
108 | rcu_read_unlock(); | |
f7b422b1 | 109 | return end; |
ce510193 | 110 | Elong_unlock: |
b514f872 | 111 | spin_lock(&dentry->d_lock); |
949854d0 NP |
112 | rcu_read_unlock(); |
113 | if (read_seqretry(&rename_lock, seq)) | |
114 | goto rename_retry; | |
f7b422b1 DH |
115 | Elong: |
116 | return ERR_PTR(-ENAMETOOLONG); | |
117 | } | |
118 | ||
55a97593 | 119 | /* |
36d43a43 DH |
120 | * nfs_d_automount - Handle crossing a mountpoint on the server |
121 | * @path - The mountpoint | |
55a97593 TM |
122 | * |
123 | * When we encounter a mountpoint on the server, we want to set up | |
124 | * a mountpoint on the client too, to prevent inode numbers from | |
125 | * colliding, and to allow "df" to work properly. | |
126 | * On NFSv4, we also want to allow for the fact that different | |
127 | * filesystems may be migrated to different servers in a failover | |
128 | * situation, and that different filesystems may want to use | |
129 | * different security flavours. | |
130 | */ | |
36d43a43 | 131 | struct vfsmount *nfs_d_automount(struct path *path) |
55a97593 TM |
132 | { |
133 | struct vfsmount *mnt; | |
36d43a43 | 134 | struct nfs_server *server = NFS_SERVER(path->dentry->d_inode); |
55a97593 | 135 | struct dentry *parent; |
a4d7f168 TM |
136 | struct nfs_fh *fh = NULL; |
137 | struct nfs_fattr *fattr = NULL; | |
55a97593 TM |
138 | int err; |
139 | ||
36d43a43 | 140 | dprintk("--> nfs_d_automount()\n"); |
54ceac45 | 141 | |
36d43a43 DH |
142 | mnt = ERR_PTR(-ESTALE); |
143 | if (IS_ROOT(path->dentry)) | |
144 | goto out_nofree; | |
44d5759d | 145 | |
36d43a43 | 146 | mnt = ERR_PTR(-ENOMEM); |
a4d7f168 TM |
147 | fh = nfs_alloc_fhandle(); |
148 | fattr = nfs_alloc_fattr(); | |
149 | if (fh == NULL || fattr == NULL) | |
36d43a43 | 150 | goto out; |
a4d7f168 | 151 | |
3110ff80 | 152 | dprintk("%s: enter\n", __func__); |
54ceac45 | 153 | |
36d43a43 DH |
154 | /* Look it up again to get its attributes */ |
155 | parent = dget_parent(path->dentry); | |
8fa5c000 | 156 | err = server->nfs_client->rpc_ops->lookup(parent->d_inode, |
36d43a43 | 157 | &path->dentry->d_name, |
a4d7f168 | 158 | fh, fattr); |
55a97593 | 159 | dput(parent); |
36d43a43 DH |
160 | if (err != 0) { |
161 | mnt = ERR_PTR(err); | |
162 | goto out; | |
163 | } | |
55a97593 | 164 | |
a4d7f168 | 165 | if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) |
f8ad9c4b | 166 | mnt = nfs_do_refmount(path->dentry); |
6b97fd3d | 167 | else |
f8ad9c4b | 168 | mnt = nfs_do_submount(path->dentry, fh, fattr); |
55a97593 | 169 | if (IS_ERR(mnt)) |
36d43a43 | 170 | goto out; |
55a97593 | 171 | |
ea5b778a DH |
172 | dprintk("%s: done, success\n", __func__); |
173 | mntget(mnt); /* prevent immediate expiration */ | |
174 | mnt_set_expiry(mnt, &nfs_automount_list); | |
175 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
36d43a43 | 176 | |
55a97593 | 177 | out: |
a4d7f168 TM |
178 | nfs_free_fattr(fattr); |
179 | nfs_free_fhandle(fh); | |
36d43a43 DH |
180 | out_nofree: |
181 | dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt); | |
182 | return mnt; | |
55a97593 TM |
183 | } |
184 | ||
92e1d5be | 185 | const struct inode_operations nfs_mountpoint_inode_operations = { |
55a97593 TM |
186 | .getattr = nfs_getattr, |
187 | }; | |
51d8fa6a | 188 | |
92e1d5be | 189 | const struct inode_operations nfs_referral_inode_operations = { |
6b97fd3d MN |
190 | }; |
191 | ||
65f27f38 | 192 | static void nfs_expire_automounts(struct work_struct *work) |
51d8fa6a | 193 | { |
65f27f38 | 194 | struct list_head *list = &nfs_automount_list; |
51d8fa6a TM |
195 | |
196 | mark_mounts_for_expiry(list); | |
197 | if (!list_empty(list)) | |
198 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
199 | } | |
200 | ||
201 | void nfs_release_automount_timer(void) | |
202 | { | |
3d39c691 | 203 | if (list_empty(&nfs_automount_list)) |
560aef74 | 204 | cancel_delayed_work(&nfs_automount_task); |
51d8fa6a | 205 | } |
f7b422b1 DH |
206 | |
207 | /* | |
208 | * Clone a mountpoint of the appropriate type | |
209 | */ | |
509de811 DH |
210 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
211 | const char *devname, | |
f7b422b1 DH |
212 | struct nfs_clone_mount *mountdata) |
213 | { | |
214 | #ifdef CONFIG_NFS_V4 | |
fd08d7e9 | 215 | struct vfsmount *mnt = ERR_PTR(-EINVAL); |
40c55319 | 216 | switch (server->nfs_client->rpc_ops->version) { |
f7b422b1 DH |
217 | case 2: |
218 | case 3: | |
54ceac45 | 219 | mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
220 | break; |
221 | case 4: | |
54ceac45 | 222 | mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
223 | } |
224 | return mnt; | |
225 | #else | |
54ceac45 | 226 | return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
227 | #endif |
228 | } | |
229 | ||
230 | /** | |
231 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary | |
f7b422b1 DH |
232 | * @dentry - parent directory |
233 | * @fh - filehandle for new root dentry | |
234 | * @fattr - attributes for new root inode | |
235 | * | |
236 | */ | |
f8ad9c4b | 237 | static struct vfsmount *nfs_do_submount(struct dentry *dentry, |
66f37509 AB |
238 | struct nfs_fh *fh, |
239 | struct nfs_fattr *fattr) | |
f7b422b1 DH |
240 | { |
241 | struct nfs_clone_mount mountdata = { | |
f8ad9c4b | 242 | .sb = dentry->d_sb, |
f7b422b1 DH |
243 | .dentry = dentry, |
244 | .fh = fh, | |
245 | .fattr = fattr, | |
246 | }; | |
247 | struct vfsmount *mnt = ERR_PTR(-ENOMEM); | |
248 | char *page = (char *) __get_free_page(GFP_USER); | |
249 | char *devname; | |
250 | ||
54ceac45 DH |
251 | dprintk("--> nfs_do_submount()\n"); |
252 | ||
3110ff80 | 253 | dprintk("%s: submounting on %s/%s\n", __func__, |
f7b422b1 DH |
254 | dentry->d_parent->d_name.name, |
255 | dentry->d_name.name); | |
256 | if (page == NULL) | |
257 | goto out; | |
b514f872 | 258 | devname = nfs_devname(dentry, page, PAGE_SIZE); |
f7b422b1 DH |
259 | mnt = (struct vfsmount *)devname; |
260 | if (IS_ERR(devname)) | |
261 | goto free_page; | |
f8ad9c4b | 262 | mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata); |
f7b422b1 DH |
263 | free_page: |
264 | free_page((unsigned long)page); | |
265 | out: | |
3110ff80 | 266 | dprintk("%s: done\n", __func__); |
54ceac45 DH |
267 | |
268 | dprintk("<-- nfs_do_submount() = %p\n", mnt); | |
f7b422b1 DH |
269 | return mnt; |
270 | } |