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 | ||
55a97593 TM |
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> | |
f7b422b1 | 17 | #include "internal.h" |
55a97593 TM |
18 | |
19 | #define NFSDBG_FACILITY NFSDBG_VFS | |
20 | ||
65f27f38 | 21 | static void nfs_expire_automounts(struct work_struct *work); |
f7b422b1 | 22 | |
a3dab293 | 23 | static LIST_HEAD(nfs_automount_list); |
65f27f38 | 24 | static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); |
51d8fa6a TM |
25 | int nfs_mountpoint_expiry_timeout = 500 * HZ; |
26 | ||
66f37509 AB |
27 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
28 | const struct dentry *dentry, | |
29 | struct nfs_fh *fh, | |
30 | struct nfs_fattr *fattr); | |
31 | ||
f7b422b1 DH |
32 | /* |
33 | * nfs_path - reconstruct the path given an arbitrary dentry | |
34 | * @base - arbitrary string to prepend to the path | |
54ceac45 | 35 | * @droot - pointer to root dentry for mountpoint |
f7b422b1 DH |
36 | * @dentry - pointer to dentry |
37 | * @buffer - result buffer | |
38 | * @buflen - length of buffer | |
39 | * | |
40 | * Helper function for constructing the path from the | |
41 | * root dentry to an arbitrary hashed dentry. | |
42 | * | |
43 | * This is mainly for use in figuring out the path on the | |
44 | * server side when automounting on top of an existing partition. | |
45 | */ | |
54ceac45 DH |
46 | char *nfs_path(const char *base, |
47 | const struct dentry *droot, | |
48 | const struct dentry *dentry, | |
f7b422b1 DH |
49 | char *buffer, ssize_t buflen) |
50 | { | |
51 | char *end = buffer+buflen; | |
52 | int namelen; | |
53 | ||
54 | *--end = '\0'; | |
55 | buflen--; | |
56 | spin_lock(&dcache_lock); | |
54ceac45 | 57 | while (!IS_ROOT(dentry) && dentry != droot) { |
f7b422b1 DH |
58 | namelen = dentry->d_name.len; |
59 | buflen -= namelen + 1; | |
60 | if (buflen < 0) | |
ce510193 | 61 | goto Elong_unlock; |
f7b422b1 DH |
62 | end -= namelen; |
63 | memcpy(end, dentry->d_name.name, namelen); | |
64 | *--end = '/'; | |
65 | dentry = dentry->d_parent; | |
66 | } | |
67 | spin_unlock(&dcache_lock); | |
68 | namelen = strlen(base); | |
69 | /* Strip off excess slashes in base string */ | |
70 | while (namelen > 0 && base[namelen - 1] == '/') | |
71 | namelen--; | |
72 | buflen -= namelen; | |
73 | if (buflen < 0) | |
74 | goto Elong; | |
75 | end -= namelen; | |
76 | memcpy(end, base, namelen); | |
77 | return end; | |
ce510193 JT |
78 | Elong_unlock: |
79 | spin_unlock(&dcache_lock); | |
f7b422b1 DH |
80 | Elong: |
81 | return ERR_PTR(-ENAMETOOLONG); | |
82 | } | |
83 | ||
55a97593 TM |
84 | /* |
85 | * nfs_follow_mountpoint - handle crossing a mountpoint on the server | |
86 | * @dentry - dentry of mountpoint | |
87 | * @nd - nameidata info | |
88 | * | |
89 | * When we encounter a mountpoint on the server, we want to set up | |
90 | * a mountpoint on the client too, to prevent inode numbers from | |
91 | * colliding, and to allow "df" to work properly. | |
92 | * On NFSv4, we also want to allow for the fact that different | |
93 | * filesystems may be migrated to different servers in a failover | |
94 | * situation, and that different filesystems may want to use | |
95 | * different security flavours. | |
96 | */ | |
97 | static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
98 | { | |
99 | struct vfsmount *mnt; | |
100 | struct nfs_server *server = NFS_SERVER(dentry->d_inode); | |
101 | struct dentry *parent; | |
102 | struct nfs_fh fh; | |
103 | struct nfs_fattr fattr; | |
104 | int err; | |
105 | ||
54ceac45 DH |
106 | dprintk("--> nfs_follow_mountpoint()\n"); |
107 | ||
55a97593 | 108 | BUG_ON(IS_ROOT(dentry)); |
3110ff80 | 109 | dprintk("%s: enter\n", __func__); |
4ac91378 JB |
110 | dput(nd->path.dentry); |
111 | nd->path.dentry = dget(dentry); | |
54ceac45 | 112 | |
55a97593 | 113 | /* Look it up again */ |
4ac91378 | 114 | parent = dget_parent(nd->path.dentry); |
8fa5c000 | 115 | err = server->nfs_client->rpc_ops->lookup(parent->d_inode, |
4ac91378 | 116 | &nd->path.dentry->d_name, |
8fa5c000 | 117 | &fh, &fattr); |
55a97593 TM |
118 | dput(parent); |
119 | if (err != 0) | |
120 | goto out_err; | |
121 | ||
6b97fd3d | 122 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) |
4ac91378 | 123 | mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry); |
6b97fd3d | 124 | else |
4ac91378 JB |
125 | mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, &fh, |
126 | &fattr); | |
55a97593 TM |
127 | err = PTR_ERR(mnt); |
128 | if (IS_ERR(mnt)) | |
129 | goto out_err; | |
130 | ||
131 | mntget(mnt); | |
4ac91378 JB |
132 | err = do_add_mount(mnt, nd, nd->path.mnt->mnt_flags|MNT_SHRINKABLE, |
133 | &nfs_automount_list); | |
55a97593 TM |
134 | if (err < 0) { |
135 | mntput(mnt); | |
136 | if (err == -EBUSY) | |
137 | goto out_follow; | |
138 | goto out_err; | |
139 | } | |
31f31db1 | 140 | path_put(&nd->path); |
4ac91378 JB |
141 | nd->path.mnt = mnt; |
142 | nd->path.dentry = dget(mnt->mnt_root); | |
51d8fa6a | 143 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
55a97593 | 144 | out: |
3110ff80 | 145 | dprintk("%s: done, returned %d\n", __func__, err); |
54ceac45 DH |
146 | |
147 | dprintk("<-- nfs_follow_mountpoint() = %d\n", err); | |
55a97593 TM |
148 | return ERR_PTR(err); |
149 | out_err: | |
1d957f9b | 150 | path_put(&nd->path); |
55a97593 TM |
151 | goto out; |
152 | out_follow: | |
4ac91378 JB |
153 | while (d_mountpoint(nd->path.dentry) && |
154 | follow_down(&nd->path.mnt, &nd->path.dentry)) | |
55a97593 TM |
155 | ; |
156 | err = 0; | |
157 | goto out; | |
158 | } | |
159 | ||
92e1d5be | 160 | const struct inode_operations nfs_mountpoint_inode_operations = { |
55a97593 TM |
161 | .follow_link = nfs_follow_mountpoint, |
162 | .getattr = nfs_getattr, | |
163 | }; | |
51d8fa6a | 164 | |
92e1d5be | 165 | const struct inode_operations nfs_referral_inode_operations = { |
6b97fd3d MN |
166 | .follow_link = nfs_follow_mountpoint, |
167 | }; | |
168 | ||
65f27f38 | 169 | static void nfs_expire_automounts(struct work_struct *work) |
51d8fa6a | 170 | { |
65f27f38 | 171 | struct list_head *list = &nfs_automount_list; |
51d8fa6a TM |
172 | |
173 | mark_mounts_for_expiry(list); | |
174 | if (!list_empty(list)) | |
175 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
176 | } | |
177 | ||
178 | void nfs_release_automount_timer(void) | |
179 | { | |
3d39c691 | 180 | if (list_empty(&nfs_automount_list)) |
560aef74 | 181 | cancel_delayed_work(&nfs_automount_task); |
51d8fa6a | 182 | } |
f7b422b1 DH |
183 | |
184 | /* | |
185 | * Clone a mountpoint of the appropriate type | |
186 | */ | |
509de811 DH |
187 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
188 | const char *devname, | |
f7b422b1 DH |
189 | struct nfs_clone_mount *mountdata) |
190 | { | |
191 | #ifdef CONFIG_NFS_V4 | |
192 | struct vfsmount *mnt = NULL; | |
40c55319 | 193 | switch (server->nfs_client->rpc_ops->version) { |
f7b422b1 DH |
194 | case 2: |
195 | case 3: | |
54ceac45 | 196 | mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
197 | break; |
198 | case 4: | |
54ceac45 | 199 | mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
200 | } |
201 | return mnt; | |
202 | #else | |
54ceac45 | 203 | return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
204 | #endif |
205 | } | |
206 | ||
207 | /** | |
208 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary | |
209 | * @mnt_parent - mountpoint of parent directory | |
210 | * @dentry - parent directory | |
211 | * @fh - filehandle for new root dentry | |
212 | * @fattr - attributes for new root inode | |
213 | * | |
214 | */ | |
66f37509 AB |
215 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
216 | const struct dentry *dentry, | |
217 | struct nfs_fh *fh, | |
218 | struct nfs_fattr *fattr) | |
f7b422b1 DH |
219 | { |
220 | struct nfs_clone_mount mountdata = { | |
221 | .sb = mnt_parent->mnt_sb, | |
222 | .dentry = dentry, | |
223 | .fh = fh, | |
224 | .fattr = fattr, | |
225 | }; | |
226 | struct vfsmount *mnt = ERR_PTR(-ENOMEM); | |
227 | char *page = (char *) __get_free_page(GFP_USER); | |
228 | char *devname; | |
229 | ||
54ceac45 DH |
230 | dprintk("--> nfs_do_submount()\n"); |
231 | ||
3110ff80 | 232 | dprintk("%s: submounting on %s/%s\n", __func__, |
f7b422b1 DH |
233 | dentry->d_parent->d_name.name, |
234 | dentry->d_name.name); | |
235 | if (page == NULL) | |
236 | goto out; | |
237 | devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); | |
238 | mnt = (struct vfsmount *)devname; | |
239 | if (IS_ERR(devname)) | |
240 | goto free_page; | |
241 | mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); | |
242 | free_page: | |
243 | free_page((unsigned long)page); | |
244 | out: | |
3110ff80 | 245 | dprintk("%s: done\n", __func__); |
54ceac45 DH |
246 | |
247 | dprintk("<-- nfs_do_submount() = %p\n", mnt); | |
f7b422b1 DH |
248 | return mnt; |
249 | } |