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 | { | |
949854d0 | 52 | char *end; |
f7b422b1 | 53 | int namelen; |
949854d0 | 54 | unsigned seq; |
f7b422b1 | 55 | |
949854d0 NP |
56 | rename_retry: |
57 | end = buffer+buflen; | |
f7b422b1 DH |
58 | *--end = '\0'; |
59 | buflen--; | |
949854d0 NP |
60 | |
61 | seq = read_seqbegin(&rename_lock); | |
62 | rcu_read_lock(); | |
54ceac45 | 63 | while (!IS_ROOT(dentry) && dentry != droot) { |
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 = '/'; | |
71 | dentry = dentry->d_parent; | |
72 | } | |
949854d0 NP |
73 | rcu_read_unlock(); |
74 | if (read_seqretry(&rename_lock, seq)) | |
75 | goto rename_retry; | |
0b75b35c TM |
76 | if (*end != '/') { |
77 | if (--buflen < 0) | |
78 | goto Elong; | |
79 | *--end = '/'; | |
80 | } | |
f7b422b1 DH |
81 | namelen = strlen(base); |
82 | /* Strip off excess slashes in base string */ | |
83 | while (namelen > 0 && base[namelen - 1] == '/') | |
84 | namelen--; | |
85 | buflen -= namelen; | |
86 | if (buflen < 0) | |
87 | goto Elong; | |
88 | end -= namelen; | |
89 | memcpy(end, base, namelen); | |
90 | return end; | |
ce510193 | 91 | Elong_unlock: |
949854d0 NP |
92 | rcu_read_unlock(); |
93 | if (read_seqretry(&rename_lock, seq)) | |
94 | goto rename_retry; | |
f7b422b1 DH |
95 | Elong: |
96 | return ERR_PTR(-ENAMETOOLONG); | |
97 | } | |
98 | ||
55a97593 | 99 | /* |
36d43a43 DH |
100 | * nfs_d_automount - Handle crossing a mountpoint on the server |
101 | * @path - The mountpoint | |
55a97593 TM |
102 | * |
103 | * When we encounter a mountpoint on the server, we want to set up | |
104 | * a mountpoint on the client too, to prevent inode numbers from | |
105 | * colliding, and to allow "df" to work properly. | |
106 | * On NFSv4, we also want to allow for the fact that different | |
107 | * filesystems may be migrated to different servers in a failover | |
108 | * situation, and that different filesystems may want to use | |
109 | * different security flavours. | |
110 | */ | |
36d43a43 | 111 | struct vfsmount *nfs_d_automount(struct path *path) |
55a97593 TM |
112 | { |
113 | struct vfsmount *mnt; | |
36d43a43 | 114 | struct nfs_server *server = NFS_SERVER(path->dentry->d_inode); |
55a97593 | 115 | struct dentry *parent; |
a4d7f168 TM |
116 | struct nfs_fh *fh = NULL; |
117 | struct nfs_fattr *fattr = NULL; | |
55a97593 TM |
118 | int err; |
119 | ||
36d43a43 | 120 | dprintk("--> nfs_d_automount()\n"); |
54ceac45 | 121 | |
36d43a43 DH |
122 | mnt = ERR_PTR(-ESTALE); |
123 | if (IS_ROOT(path->dentry)) | |
124 | goto out_nofree; | |
44d5759d | 125 | |
36d43a43 | 126 | mnt = ERR_PTR(-ENOMEM); |
a4d7f168 TM |
127 | fh = nfs_alloc_fhandle(); |
128 | fattr = nfs_alloc_fattr(); | |
129 | if (fh == NULL || fattr == NULL) | |
36d43a43 | 130 | goto out; |
a4d7f168 | 131 | |
3110ff80 | 132 | dprintk("%s: enter\n", __func__); |
54ceac45 | 133 | |
36d43a43 DH |
134 | /* Look it up again to get its attributes */ |
135 | parent = dget_parent(path->dentry); | |
8fa5c000 | 136 | err = server->nfs_client->rpc_ops->lookup(parent->d_inode, |
36d43a43 | 137 | &path->dentry->d_name, |
a4d7f168 | 138 | fh, fattr); |
55a97593 | 139 | dput(parent); |
36d43a43 DH |
140 | if (err != 0) { |
141 | mnt = ERR_PTR(err); | |
142 | goto out; | |
143 | } | |
55a97593 | 144 | |
a4d7f168 | 145 | if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) |
36d43a43 | 146 | mnt = nfs_do_refmount(path->mnt, path->dentry); |
6b97fd3d | 147 | else |
36d43a43 | 148 | mnt = nfs_do_submount(path->mnt, path->dentry, fh, fattr); |
55a97593 | 149 | if (IS_ERR(mnt)) |
36d43a43 | 150 | goto out; |
55a97593 | 151 | |
ea5b778a DH |
152 | dprintk("%s: done, success\n", __func__); |
153 | mntget(mnt); /* prevent immediate expiration */ | |
154 | mnt_set_expiry(mnt, &nfs_automount_list); | |
155 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
36d43a43 | 156 | |
55a97593 | 157 | out: |
a4d7f168 TM |
158 | nfs_free_fattr(fattr); |
159 | nfs_free_fhandle(fh); | |
36d43a43 DH |
160 | out_nofree: |
161 | dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt); | |
162 | return mnt; | |
55a97593 TM |
163 | } |
164 | ||
92e1d5be | 165 | const struct inode_operations nfs_mountpoint_inode_operations = { |
55a97593 TM |
166 | .getattr = nfs_getattr, |
167 | }; | |
51d8fa6a | 168 | |
92e1d5be | 169 | const struct inode_operations nfs_referral_inode_operations = { |
6b97fd3d MN |
170 | }; |
171 | ||
65f27f38 | 172 | static void nfs_expire_automounts(struct work_struct *work) |
51d8fa6a | 173 | { |
65f27f38 | 174 | struct list_head *list = &nfs_automount_list; |
51d8fa6a TM |
175 | |
176 | mark_mounts_for_expiry(list); | |
177 | if (!list_empty(list)) | |
178 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); | |
179 | } | |
180 | ||
181 | void nfs_release_automount_timer(void) | |
182 | { | |
3d39c691 | 183 | if (list_empty(&nfs_automount_list)) |
560aef74 | 184 | cancel_delayed_work(&nfs_automount_task); |
51d8fa6a | 185 | } |
f7b422b1 DH |
186 | |
187 | /* | |
188 | * Clone a mountpoint of the appropriate type | |
189 | */ | |
509de811 DH |
190 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
191 | const char *devname, | |
f7b422b1 DH |
192 | struct nfs_clone_mount *mountdata) |
193 | { | |
194 | #ifdef CONFIG_NFS_V4 | |
fd08d7e9 | 195 | struct vfsmount *mnt = ERR_PTR(-EINVAL); |
40c55319 | 196 | switch (server->nfs_client->rpc_ops->version) { |
f7b422b1 DH |
197 | case 2: |
198 | case 3: | |
54ceac45 | 199 | mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
200 | break; |
201 | case 4: | |
54ceac45 | 202 | mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
203 | } |
204 | return mnt; | |
205 | #else | |
54ceac45 | 206 | return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
f7b422b1 DH |
207 | #endif |
208 | } | |
209 | ||
210 | /** | |
211 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary | |
212 | * @mnt_parent - mountpoint of parent directory | |
213 | * @dentry - parent directory | |
214 | * @fh - filehandle for new root dentry | |
215 | * @fattr - attributes for new root inode | |
216 | * | |
217 | */ | |
66f37509 AB |
218 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
219 | const struct dentry *dentry, | |
220 | struct nfs_fh *fh, | |
221 | struct nfs_fattr *fattr) | |
f7b422b1 DH |
222 | { |
223 | struct nfs_clone_mount mountdata = { | |
224 | .sb = mnt_parent->mnt_sb, | |
225 | .dentry = dentry, | |
226 | .fh = fh, | |
227 | .fattr = fattr, | |
228 | }; | |
229 | struct vfsmount *mnt = ERR_PTR(-ENOMEM); | |
230 | char *page = (char *) __get_free_page(GFP_USER); | |
231 | char *devname; | |
232 | ||
54ceac45 DH |
233 | dprintk("--> nfs_do_submount()\n"); |
234 | ||
3110ff80 | 235 | dprintk("%s: submounting on %s/%s\n", __func__, |
f7b422b1 DH |
236 | dentry->d_parent->d_name.name, |
237 | dentry->d_name.name); | |
238 | if (page == NULL) | |
239 | goto out; | |
240 | devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); | |
241 | mnt = (struct vfsmount *)devname; | |
242 | if (IS_ERR(devname)) | |
243 | goto free_page; | |
244 | mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); | |
245 | free_page: | |
246 | free_page((unsigned long)page); | |
247 | out: | |
3110ff80 | 248 | dprintk("%s: done\n", __func__); |
54ceac45 DH |
249 | |
250 | dprintk("<-- nfs_do_submount() = %p\n", mnt); | |
f7b422b1 DH |
251 | return mnt; |
252 | } |