Root/
1 | /* |
2 | * linux/fs/nfs/namespace.c |
3 | * |
4 | * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> |
5 | * - Modified by David Howells <dhowells@redhat.com> |
6 | * |
7 | * NFS namespace |
8 | */ |
9 | |
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> |
17 | #include "internal.h" |
18 | |
19 | #define NFSDBG_FACILITY NFSDBG_VFS |
20 | |
21 | static void nfs_expire_automounts(struct work_struct *work); |
22 | |
23 | static LIST_HEAD(nfs_automount_list); |
24 | static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts); |
25 | int nfs_mountpoint_expiry_timeout = 500 * HZ; |
26 | |
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 | |
32 | /* |
33 | * nfs_path - reconstruct the path given an arbitrary dentry |
34 | * @base - arbitrary string to prepend to the path |
35 | * @droot - pointer to root dentry for mountpoint |
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 | */ |
46 | char *nfs_path(const char *base, |
47 | const struct dentry *droot, |
48 | const struct dentry *dentry, |
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); |
57 | while (!IS_ROOT(dentry) && dentry != droot) { |
58 | namelen = dentry->d_name.len; |
59 | buflen -= namelen + 1; |
60 | if (buflen < 0) |
61 | goto Elong_unlock; |
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 | if (*end != '/') { |
69 | if (--buflen < 0) |
70 | goto Elong; |
71 | *--end = '/'; |
72 | } |
73 | namelen = strlen(base); |
74 | /* Strip off excess slashes in base string */ |
75 | while (namelen > 0 && base[namelen - 1] == '/') |
76 | namelen--; |
77 | buflen -= namelen; |
78 | if (buflen < 0) |
79 | goto Elong; |
80 | end -= namelen; |
81 | memcpy(end, base, namelen); |
82 | return end; |
83 | Elong_unlock: |
84 | spin_unlock(&dcache_lock); |
85 | Elong: |
86 | return ERR_PTR(-ENAMETOOLONG); |
87 | } |
88 | |
89 | /* |
90 | * nfs_follow_mountpoint - handle crossing a mountpoint on the server |
91 | * @dentry - dentry of mountpoint |
92 | * @nd - nameidata info |
93 | * |
94 | * When we encounter a mountpoint on the server, we want to set up |
95 | * a mountpoint on the client too, to prevent inode numbers from |
96 | * colliding, and to allow "df" to work properly. |
97 | * On NFSv4, we also want to allow for the fact that different |
98 | * filesystems may be migrated to different servers in a failover |
99 | * situation, and that different filesystems may want to use |
100 | * different security flavours. |
101 | */ |
102 | static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) |
103 | { |
104 | struct vfsmount *mnt; |
105 | struct nfs_server *server = NFS_SERVER(dentry->d_inode); |
106 | struct dentry *parent; |
107 | struct nfs_fh fh; |
108 | struct nfs_fattr fattr; |
109 | int err; |
110 | |
111 | dprintk("--> nfs_follow_mountpoint()\n"); |
112 | |
113 | err = -ESTALE; |
114 | if (IS_ROOT(dentry)) |
115 | goto out_err; |
116 | |
117 | dprintk("%s: enter\n", __func__); |
118 | dput(nd->path.dentry); |
119 | nd->path.dentry = dget(dentry); |
120 | |
121 | /* Look it up again */ |
122 | parent = dget_parent(nd->path.dentry); |
123 | err = server->nfs_client->rpc_ops->lookup(parent->d_inode, |
124 | &nd->path.dentry->d_name, |
125 | &fh, &fattr); |
126 | dput(parent); |
127 | if (err != 0) |
128 | goto out_err; |
129 | |
130 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) |
131 | mnt = nfs_do_refmount(nd->path.mnt, nd->path.dentry); |
132 | else |
133 | mnt = nfs_do_submount(nd->path.mnt, nd->path.dentry, &fh, |
134 | &fattr); |
135 | err = PTR_ERR(mnt); |
136 | if (IS_ERR(mnt)) |
137 | goto out_err; |
138 | |
139 | mntget(mnt); |
140 | err = do_add_mount(mnt, &nd->path, nd->path.mnt->mnt_flags|MNT_SHRINKABLE, |
141 | &nfs_automount_list); |
142 | if (err < 0) { |
143 | mntput(mnt); |
144 | if (err == -EBUSY) |
145 | goto out_follow; |
146 | goto out_err; |
147 | } |
148 | path_put(&nd->path); |
149 | nd->path.mnt = mnt; |
150 | nd->path.dentry = dget(mnt->mnt_root); |
151 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
152 | out: |
153 | dprintk("%s: done, returned %d\n", __func__, err); |
154 | |
155 | dprintk("<-- nfs_follow_mountpoint() = %d\n", err); |
156 | return ERR_PTR(err); |
157 | out_err: |
158 | path_put(&nd->path); |
159 | goto out; |
160 | out_follow: |
161 | while (d_mountpoint(nd->path.dentry) && |
162 | follow_down(&nd->path)) |
163 | ; |
164 | err = 0; |
165 | goto out; |
166 | } |
167 | |
168 | const struct inode_operations nfs_mountpoint_inode_operations = { |
169 | .follow_link = nfs_follow_mountpoint, |
170 | .getattr = nfs_getattr, |
171 | }; |
172 | |
173 | const struct inode_operations nfs_referral_inode_operations = { |
174 | .follow_link = nfs_follow_mountpoint, |
175 | }; |
176 | |
177 | static void nfs_expire_automounts(struct work_struct *work) |
178 | { |
179 | struct list_head *list = &nfs_automount_list; |
180 | |
181 | mark_mounts_for_expiry(list); |
182 | if (!list_empty(list)) |
183 | schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout); |
184 | } |
185 | |
186 | void nfs_release_automount_timer(void) |
187 | { |
188 | if (list_empty(&nfs_automount_list)) |
189 | cancel_delayed_work(&nfs_automount_task); |
190 | } |
191 | |
192 | /* |
193 | * Clone a mountpoint of the appropriate type |
194 | */ |
195 | static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server, |
196 | const char *devname, |
197 | struct nfs_clone_mount *mountdata) |
198 | { |
199 | #ifdef CONFIG_NFS_V4 |
200 | struct vfsmount *mnt = ERR_PTR(-EINVAL); |
201 | switch (server->nfs_client->rpc_ops->version) { |
202 | case 2: |
203 | case 3: |
204 | mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
205 | break; |
206 | case 4: |
207 | mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata); |
208 | } |
209 | return mnt; |
210 | #else |
211 | return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata); |
212 | #endif |
213 | } |
214 | |
215 | /** |
216 | * nfs_do_submount - set up mountpoint when crossing a filesystem boundary |
217 | * @mnt_parent - mountpoint of parent directory |
218 | * @dentry - parent directory |
219 | * @fh - filehandle for new root dentry |
220 | * @fattr - attributes for new root inode |
221 | * |
222 | */ |
223 | static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent, |
224 | const struct dentry *dentry, |
225 | struct nfs_fh *fh, |
226 | struct nfs_fattr *fattr) |
227 | { |
228 | struct nfs_clone_mount mountdata = { |
229 | .sb = mnt_parent->mnt_sb, |
230 | .dentry = dentry, |
231 | .fh = fh, |
232 | .fattr = fattr, |
233 | }; |
234 | struct vfsmount *mnt = ERR_PTR(-ENOMEM); |
235 | char *page = (char *) __get_free_page(GFP_USER); |
236 | char *devname; |
237 | |
238 | dprintk("--> nfs_do_submount()\n"); |
239 | |
240 | dprintk("%s: submounting on %s/%s\n", __func__, |
241 | dentry->d_parent->d_name.name, |
242 | dentry->d_name.name); |
243 | if (page == NULL) |
244 | goto out; |
245 | devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE); |
246 | mnt = (struct vfsmount *)devname; |
247 | if (IS_ERR(devname)) |
248 | goto free_page; |
249 | mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata); |
250 | free_page: |
251 | free_page((unsigned long)page); |
252 | out: |
253 | dprintk("%s: done\n", __func__); |
254 | |
255 | dprintk("<-- nfs_do_submount() = %p\n", mnt); |
256 | return mnt; |
257 | } |
258 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9