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_in - pointer to dentry
34 * @buffer - result buffer
35 * @buflen_in - length of buffer
36 * @flags - options (see below)
38 * Helper function for constructing the server pathname
39 * by arbitrary hashed dentry.
41 * This is mainly for use in figuring out the path on the
42 * server side when automounting on top of an existing partition
43 * and in generating /proc/mounts and friends.
46 * NFS_PATH_CANONICAL: ensure there is exactly one slash after
47 * the original device (export) name
48 * (if unset, the original name is returned verbatim)
50 char *nfs_path(char **p, struct dentry *dentry_in, char *buffer,
51 ssize_t buflen_in, unsigned flags)
57 struct dentry *dentry;
67 seq = read_seqbegin(&rename_lock);
70 spin_lock(&dentry->d_lock);
73 namelen = dentry->d_name.len;
74 buflen -= namelen + 1;
78 memcpy(end, dentry->d_name.name, namelen);
80 spin_unlock(&dentry->d_lock);
81 dentry = dentry->d_parent;
83 if (read_seqretry(&rename_lock, seq)) {
84 spin_unlock(&dentry->d_lock);
88 if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
90 spin_unlock(&dentry->d_lock);
97 base = dentry->d_fsdata;
99 spin_unlock(&dentry->d_lock);
104 namelen = strlen(base);
106 /* Strip off excess slashes in base string */
107 while (namelen > 0 && base[namelen - 1] == '/')
112 spin_unlock(&dentry->d_lock);
117 memcpy(end, base, namelen);
118 spin_unlock(&dentry->d_lock);
122 spin_unlock(&dentry->d_lock);
124 if (read_seqretry(&rename_lock, seq))
127 return ERR_PTR(-ENAMETOOLONG);
129 EXPORT_SYMBOL_GPL(nfs_path);
132 * nfs_d_automount - Handle crossing a mountpoint on the server
133 * @path - The mountpoint
135 * When we encounter a mountpoint on the server, we want to set up
136 * a mountpoint on the client too, to prevent inode numbers from
137 * colliding, and to allow "df" to work properly.
138 * On NFSv4, we also want to allow for the fact that different
139 * filesystems may be migrated to different servers in a failover
140 * situation, and that different filesystems may want to use
141 * different security flavours.
143 struct vfsmount *nfs_d_automount(struct path *path)
145 struct vfsmount *mnt;
146 struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
147 struct nfs_fh *fh = NULL;
148 struct nfs_fattr *fattr = NULL;
150 dprintk("--> nfs_d_automount()\n");
152 mnt = ERR_PTR(-ESTALE);
153 if (IS_ROOT(path->dentry))
156 mnt = ERR_PTR(-ENOMEM);
157 fh = nfs_alloc_fhandle();
158 fattr = nfs_alloc_fattr();
159 if (fh == NULL || fattr == NULL)
162 dprintk("%s: enter\n", __func__);
164 mnt = server->nfs_client->rpc_ops->submount(server, path->dentry, fh, fattr);
168 dprintk("%s: done, success\n", __func__);
169 mntget(mnt); /* prevent immediate expiration */
170 mnt_set_expiry(mnt, &nfs_automount_list);
171 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
174 nfs_free_fattr(fattr);
175 nfs_free_fhandle(fh);
178 dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt));
180 dprintk("<-- %s() = %p\n", __func__, mnt);
185 nfs_namespace_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
187 if (NFS_FH(d_inode(dentry))->size != 0)
188 return nfs_getattr(mnt, dentry, stat);
189 generic_fillattr(d_inode(dentry), stat);
194 nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
196 if (NFS_FH(d_inode(dentry))->size != 0)
197 return nfs_setattr(dentry, attr);
201 const struct inode_operations nfs_mountpoint_inode_operations = {
202 .getattr = nfs_getattr,
203 .setattr = nfs_setattr,
206 const struct inode_operations nfs_referral_inode_operations = {
207 .getattr = nfs_namespace_getattr,
208 .setattr = nfs_namespace_setattr,
211 static void nfs_expire_automounts(struct work_struct *work)
213 struct list_head *list = &nfs_automount_list;
215 mark_mounts_for_expiry(list);
216 if (!list_empty(list))
217 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
220 void nfs_release_automount_timer(void)
222 if (list_empty(&nfs_automount_list))
223 cancel_delayed_work(&nfs_automount_task);
227 * Clone a mountpoint of the appropriate type
229 static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
231 struct nfs_clone_mount *mountdata)
233 return vfs_submount(mountdata->dentry, &nfs_xdev_fs_type, devname, mountdata);
237 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
238 * @dentry - parent directory
239 * @fh - filehandle for new root dentry
240 * @fattr - attributes for new root inode
241 * @authflavor - security flavor to use when performing the mount
244 struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
245 struct nfs_fattr *fattr, rpc_authflavor_t authflavor)
247 struct nfs_clone_mount mountdata = {
252 .authflavor = authflavor,
254 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
255 char *page = (char *) __get_free_page(GFP_USER);
258 dprintk("--> nfs_do_submount()\n");
260 dprintk("%s: submounting on %pd2\n", __func__,
264 devname = nfs_devname(dentry, page, PAGE_SIZE);
265 mnt = (struct vfsmount *)devname;
268 mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
270 free_page((unsigned long)page);
272 dprintk("%s: done\n", __func__);
274 dprintk("<-- nfs_do_submount() = %p\n", mnt);
277 EXPORT_SYMBOL_GPL(nfs_do_submount);
279 struct vfsmount *nfs_submount(struct nfs_server *server, struct dentry *dentry,
280 struct nfs_fh *fh, struct nfs_fattr *fattr)
283 struct dentry *parent = dget_parent(dentry);
285 /* Look it up again to get its attributes */
286 err = server->nfs_client->rpc_ops->lookup(d_inode(parent), &dentry->d_name, fh, fattr, NULL);
291 return nfs_do_submount(dentry, fh, fattr, server->client->cl_auth->au_flavor);
293 EXPORT_SYMBOL_GPL(nfs_submount);