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 | ||
66f37509 AB |
28 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
29 | const struct dentry *dentry, | |
30 | struct nfs_fh *fh, | |
31 | struct nfs_fattr *fattr); | |
32 | ||
f7b422b1 DH |
33 | /* |
34 | * nfs_path - reconstruct the path given an arbitrary dentry | |
35 | * @base - arbitrary string to prepend to the path | |
54ceac45 | 36 | * @droot - pointer to root dentry for mountpoint |
f7b422b1 DH |
37 | * @dentry - pointer to dentry |
38 | * @buffer - result buffer | |
39 | * @buflen - length of buffer | |
40 | * | |
41 | * Helper function for constructing the path from the | |
42 | * root dentry to an arbitrary hashed dentry. | |
43 | * | |
44 | * This is mainly for use in figuring out the path on the | |
45 | * server side when automounting on top of an existing partition. | |
46 | */ | |
54ceac45 DH |
47 | char *nfs_path(const char *base, |
48 | const struct dentry *droot, | |
49 | const struct dentry *dentry, | |
f7b422b1 DH |
50 | char *buffer, ssize_t buflen) |
51 | { | |
52 | char *end = buffer+buflen; | |
53 | int namelen; | |
54 | ||
55 | *--end = '\0'; | |
56 | buflen--; | |
57 | spin_lock(&dcache_lock); | |
54ceac45 | 58 | while (!IS_ROOT(dentry) && dentry != droot) { |
f7b422b1 DH |
59 | namelen = dentry->d_name.len; |
60 | buflen -= namelen + 1; | |
61 | if (buflen < 0) | |
ce510193 | 62 | goto Elong_unlock; |
f7b422b1 DH |
63 | end -= namelen; |
64 | memcpy(end, dentry->d_name.name, namelen); | |
65 | *--end = '/'; | |
66 | dentry = dentry->d_parent; | |
67 | } | |
68 | spin_unlock(&dcache_lock); | |
0b75b35c TM |
69 | if (*end != '/') { |
70 | if (--buflen < 0) | |
71 | goto Elong; | |
72 | *--end = '/'; | |
73 | } | |
f7b422b1 DH |
74 | namelen = strlen(base); |
75 | /* Strip off excess slashes in base string */ | |
76 | while (namelen > 0 && base[namelen - 1] == '/') | |
77 | namelen--; | |
78 | buflen -= namelen; | |
79 | if (buflen < 0) | |
80 | goto Elong; | |
81 | end -= namelen; | |
82 | memcpy(end, base, namelen); | |
83 | return end; | |
ce510193 JT |
84 | Elong_unlock: |
85 | spin_unlock(&dcache_lock); | |
f7b422b1 DH |
86 | Elong: |
87 | return ERR_PTR(-ENAMETOOLONG); | |
88 | } | |
89 | ||
55a97593 TM |
90 | /* |
91 | * nfs_follow_mountpoint - handle crossing a mountpoint on the server | |
92 | * @dentry - dentry of mountpoint | |
93 | * @nd - nameidata info | |
94 | * | |
95 | * When we encounter a mountpoint on the server, we want to set up | |
96 | * a mountpoint on the client too, to prevent inode numbers from | |
97 | * colliding, and to allow "df" to work properly. | |
98 | * On NFSv4, we also want to allow for the fact that different | |
99 | * filesystems may be migrated to different servers in a failover | |
100 | * situation, and that different filesystems may want to use | |
101 | * different security flavours. | |
102 | */ | |
103 | static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
104 | { | |
105 | struct vfsmount *mnt; | |
106 | struct nfs_server *server = NFS_SERVER(dentry->d_inode); | |
107 | struct dentry *parent; | |
108 | struct nfs_fh fh; | |
109 | struct nfs_fattr fattr; | |
110 | int err; | |
111 | ||
54ceac45 DH |
112 | dprintk("--> nfs_follow_mountpoint()\n"); |
113 | ||
44d5759d DL |
114 | err = -ESTALE; |
115 | if (IS_ROOT(dentry)) | |
116 | goto out_err; | |
117 | ||
3110ff80 | 118 | dprintk("%s: enter\n", __func__); |
4ac91378 JB |
119 | dput(nd->path.dentry); |
120 | nd->path.dentry = dget(dentry); | |
54ceac45 | 121 | |
55a97593 | 122 | /* Look it up again */ |
4ac91378 | 123 | parent = dget_parent(nd->path.dentry); |
8fa5c000 | 124 | err = server->nfs_client->rpc_ops->lookup(parent->d_inode, |
4ac91378 | 125 | &nd->path.dentry->d_name, |
8fa5c000 | 126 | &fh, &fattr); |
55a97593 TM |
127 | dput(parent); |
128 | if (err != 0) | |
129 | goto out_err; | |
130 | ||
6b97fd3d | 131 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) |
4ac91378 | 132 | mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry); |
6b97fd3d | 133 | else |
4ac91378 JB |
134 | mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, &fh, |
135 | &fattr); | |
55a97593 TM |
136 | err = PTR_ERR(mnt); |
137 | if (IS_ERR(mnt)) | |
138 | goto out_err; | |
139 | ||
140 | mntget(mnt); | |
8d66bf54 | 141 | err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE, |
4ac91378 | 142 | &nfs_automount_list); |
55a97593 TM |
143 | if (err < 0) { |
144 | mntput(mnt); | |
145 | if (err == -EBUSY) | |
146 | goto out_follow; | |
147 | goto out_err; | |
148 | } | |
31f31db1 | 149 | path_put(&nd->path); |
4ac91378 JB |
150 | nd->path.mnt = mnt; |
151 | nd->path.dentry = dget(mnt->mnt_root); | |
51d8fa6a | 152 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
55a97593 | 153 | out: |
3110ff80 | 154 | dprintk("%s: done, returned %d\n", __func__, err); |
54ceac45 DH |
155 | |
156 | dprintk("<-- nfs_follow_mountpoint() = %d\n", err); | |
55a97593 TM |
157 | return ERR_PTR(err); |
158 | out_err: | |
1d957f9b | 159 | path_put(&nd->path); |
55a97593 TM |
160 | goto out; |
161 | out_follow: | |
4ac91378 | 162 | while (d_mountpoint(nd->path.dentry) && |
9393bd07 | 163 | follow_down(&nd->path)) |
55a97593 TM |
164 | ; |
165 | err = 0; | |
166 | goto out; | |
167 | } | |
168 | ||
92e1d5be | 169 | const struct inode_operations nfs_mountpoint_inode_operations = { |
55a97593 TM |
170 | .follow_link = nfs_follow_mountpoint, |
171 | .getattr = nfs_getattr, | |
172 | }; | |
51d8fa6a | 173 | |
92e1d5be | 174 | const struct inode_operations nfs_referral_inode_operations = { |
6b97fd3d MN |
175 | .follow_link = nfs_follow_mountpoint, |
176 | }; | |
177 | ||
65f27f38 | 178 | static void nfs_expire_automounts(struct work_struct *work) |
51d8fa6a | 179 | { |
65f27f38 | 180 | struct list_head *list = &nfs_automount_list; |
51d8fa6a TM |
181 | |
182 | mark_mounts_for_expiry(list); | |
183 | if (!list_empty(list)) | |
184 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
185 | } | |
186 | ||
187 | void nfs_release_automount_timer(void) | |
188 | { | |
3d39c691 | 189 | if (list_empty(&nfs_automount_list)) |
560aef74 | 190 | cancel_delayed_work(&nfs_automount_task); |
51d8fa6a | 191 | } |
f7b422b1 DH |
192 | |
193 | /* | |
194 | * Clone a mountpoint of the appropriate type | |
195 | */ | |
509de811 DH |
196 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
197 | const char *devname, | |
f7b422b1 DH |
198 | struct nfs_clone_mount *mountdata) |
199 | { | |
200 | #ifdef CONFIG_NFS_V4 | |
fd08d7e9 | 201 | struct vfsmount *mnt = ERR_PTR(-EINVAL); |
40c55319 | 202 | switch (server->nfs_client->rpc_ops->version) { |
f7b422b1 DH |
203 | case 2: |
204 | case 3: | |
54ceac45 | 205 | mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
206 | break; |
207 | case 4: | |
54ceac45 | 208 | mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
209 | } |
210 | return mnt; | |
211 | #else | |
54ceac45 | 212 | return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
213 | #endif |
214 | } | |
215 | ||
216 | /** | |
217 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary | |
218 | * @mnt_parent - mountpoint of parent directory | |
219 | * @dentry - parent directory | |
220 | * @fh - filehandle for new root dentry | |
221 | * @fattr - attributes for new root inode | |
222 | * | |
223 | */ | |
66f37509 AB |
224 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
225 | const struct dentry *dentry, | |
226 | struct nfs_fh *fh, | |
227 | struct nfs_fattr *fattr) | |
f7b422b1 DH |
228 | { |
229 | struct nfs_clone_mount mountdata = { | |
230 | .sb = mnt_parent->mnt_sb, | |
231 | .dentry = dentry, | |
232 | .fh = fh, | |
233 | .fattr = fattr, | |
234 | }; | |
235 | struct vfsmount *mnt = ERR_PTR(-ENOMEM); | |
236 | char *page = (char *) __get_free_page(GFP_USER); | |
237 | char *devname; | |
238 | ||
54ceac45 DH |
239 | dprintk("--> nfs_do_submount()\n"); |
240 | ||
3110ff80 | 241 | dprintk("%s: submounting on %s/%s\n", __func__, |
f7b422b1 DH |
242 | dentry->d_parent->d_name.name, |
243 | dentry->d_name.name); | |
244 | if (page == NULL) | |
245 | goto out; | |
246 | devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); | |
247 | mnt = (struct vfsmount *)devname; | |
248 | if (IS_ERR(devname)) | |
249 | goto free_page; | |
250 | mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); | |
251 | free_page: | |
252 | free_page((unsigned long)page); | |
253 | out: | |
3110ff80 | 254 | dprintk("%s: done\n", __func__); |
54ceac45 DH |
255 | |
256 | dprintk("<-- nfs_do_submount() = %p\n", mnt); | |
f7b422b1 DH |
257 | return mnt; |
258 | } |