2 * linux/fs/nfs/namespace.c
4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
5 * - Modified by David Howells <dhowells@redhat.com>
10 #include <linux/module.h>
11 #include <linux/dcache.h>
12 #include <linux/gfp.h>
13 #include <linux/mount.h>
14 #include <linux/namei.h>
15 #include <linux/nfs_fs.h>
16 #include <linux/string.h>
17 #include <linux/sunrpc/clnt.h>
18 #include <linux/vfs.h>
19 #include <linux/sunrpc/gss_api.h>
22 #define NFSDBG_FACILITY NFSDBG_VFS
24 static void nfs_expire_automounts(struct work_struct
*work
);
26 static LIST_HEAD(nfs_automount_list
);
27 static DECLARE_DELAYED_WORK(nfs_automount_task
, nfs_expire_automounts
);
28 int nfs_mountpoint_expiry_timeout
= 500 * HZ
;
31 * nfs_path - reconstruct the path given an arbitrary dentry
32 * @base - used to return pointer to the end of devname part of path
33 * @dentry - pointer to dentry
34 * @buffer - result buffer
35 * @buflen - length of buffer
37 * Helper function for constructing the server pathname
38 * by arbitrary hashed dentry.
40 * This is mainly for use in figuring out the path on the
41 * server side when automounting on top of an existing partition
42 * and in generating /proc/mounts and friends.
44 char *nfs_path(char **p
, struct dentry
*dentry
, char *buffer
, ssize_t buflen
)
56 seq
= read_seqbegin(&rename_lock
);
59 spin_lock(&dentry
->d_lock
);
62 namelen
= dentry
->d_name
.len
;
63 buflen
-= namelen
+ 1;
67 memcpy(end
, dentry
->d_name
.name
, namelen
);
69 spin_unlock(&dentry
->d_lock
);
70 dentry
= dentry
->d_parent
;
72 if (read_seqretry(&rename_lock
, seq
)) {
73 spin_unlock(&dentry
->d_lock
);
79 spin_unlock(&dentry
->d_lock
);
86 base
= dentry
->d_fsdata
;
88 spin_unlock(&dentry
->d_lock
);
93 namelen
= strlen(base
);
94 /* Strip off excess slashes in base string */
95 while (namelen
> 0 && base
[namelen
- 1] == '/')
99 spin_unlock(&dentry
->d_lock
);
104 memcpy(end
, base
, namelen
);
105 spin_unlock(&dentry
->d_lock
);
109 spin_unlock(&dentry
->d_lock
);
111 if (read_seqretry(&rename_lock
, seq
))
114 return ERR_PTR(-ENAMETOOLONG
);
116 EXPORT_SYMBOL_GPL(nfs_path
);
119 * nfs_d_automount - Handle crossing a mountpoint on the server
120 * @path - The mountpoint
122 * When we encounter a mountpoint on the server, we want to set up
123 * a mountpoint on the client too, to prevent inode numbers from
124 * colliding, and to allow "df" to work properly.
125 * On NFSv4, we also want to allow for the fact that different
126 * filesystems may be migrated to different servers in a failover
127 * situation, and that different filesystems may want to use
128 * different security flavours.
130 struct vfsmount
*nfs_d_automount(struct path
*path
)
132 struct vfsmount
*mnt
;
133 struct nfs_server
*server
= NFS_SERVER(path
->dentry
->d_inode
);
134 struct nfs_fh
*fh
= NULL
;
135 struct nfs_fattr
*fattr
= NULL
;
137 dprintk("--> nfs_d_automount()\n");
139 mnt
= ERR_PTR(-ESTALE
);
140 if (IS_ROOT(path
->dentry
))
143 mnt
= ERR_PTR(-ENOMEM
);
144 fh
= nfs_alloc_fhandle();
145 fattr
= nfs_alloc_fattr();
146 if (fh
== NULL
|| fattr
== NULL
)
149 dprintk("%s: enter\n", __func__
);
151 mnt
= server
->nfs_client
->rpc_ops
->submount(server
, path
->dentry
, fh
, fattr
);
155 dprintk("%s: done, success\n", __func__
);
156 mntget(mnt
); /* prevent immediate expiration */
157 mnt_set_expiry(mnt
, &nfs_automount_list
);
158 schedule_delayed_work(&nfs_automount_task
, nfs_mountpoint_expiry_timeout
);
161 nfs_free_fattr(fattr
);
162 nfs_free_fhandle(fh
);
165 dprintk("<-- %s(): error %ld\n", __func__
, PTR_ERR(mnt
));
167 dprintk("<-- %s() = %p\n", __func__
, mnt
);
171 const struct inode_operations nfs_mountpoint_inode_operations
= {
172 .getattr
= nfs_getattr
,
175 const struct inode_operations nfs_referral_inode_operations
= {
178 static void nfs_expire_automounts(struct work_struct
*work
)
180 struct list_head
*list
= &nfs_automount_list
;
182 mark_mounts_for_expiry(list
);
183 if (!list_empty(list
))
184 schedule_delayed_work(&nfs_automount_task
, nfs_mountpoint_expiry_timeout
);
187 void nfs_release_automount_timer(void)
189 if (list_empty(&nfs_automount_list
))
190 cancel_delayed_work(&nfs_automount_task
);
194 * Clone a mountpoint of the appropriate type
196 static struct vfsmount
*nfs_do_clone_mount(struct nfs_server
*server
,
198 struct nfs_clone_mount
*mountdata
)
200 return vfs_kern_mount(&nfs_xdev_fs_type
, 0, devname
, mountdata
);
204 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
205 * @dentry - parent directory
206 * @fh - filehandle for new root dentry
207 * @fattr - attributes for new root inode
208 * @authflavor - security flavor to use when performing the mount
211 struct vfsmount
*nfs_do_submount(struct dentry
*dentry
, struct nfs_fh
*fh
,
212 struct nfs_fattr
*fattr
, rpc_authflavor_t authflavor
)
214 struct nfs_clone_mount mountdata
= {
219 .authflavor
= authflavor
,
221 struct vfsmount
*mnt
= ERR_PTR(-ENOMEM
);
222 char *page
= (char *) __get_free_page(GFP_USER
);
225 dprintk("--> nfs_do_submount()\n");
227 dprintk("%s: submounting on %s/%s\n", __func__
,
228 dentry
->d_parent
->d_name
.name
,
229 dentry
->d_name
.name
);
232 devname
= nfs_devname(dentry
, page
, PAGE_SIZE
);
233 mnt
= (struct vfsmount
*)devname
;
236 mnt
= nfs_do_clone_mount(NFS_SB(dentry
->d_sb
), devname
, &mountdata
);
238 free_page((unsigned long)page
);
240 dprintk("%s: done\n", __func__
);
242 dprintk("<-- nfs_do_submount() = %p\n", mnt
);
245 EXPORT_SYMBOL_GPL(nfs_do_submount
);
247 struct vfsmount
*nfs_submount(struct nfs_server
*server
, struct dentry
*dentry
,
248 struct nfs_fh
*fh
, struct nfs_fattr
*fattr
)
251 struct dentry
*parent
= dget_parent(dentry
);
253 /* Look it up again to get its attributes */
254 err
= server
->nfs_client
->rpc_ops
->lookup(parent
->d_inode
, &dentry
->d_name
, fh
, fattr
);
259 return nfs_do_submount(dentry
, fh
, fattr
, server
->client
->cl_auth
->au_flavor
);
261 EXPORT_SYMBOL_GPL(nfs_submount
);