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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>
20#include "internal.h"
21
22#define NFSDBG_FACILITY NFSDBG_VFS
23
24static void nfs_expire_automounts(struct work_struct *work);
25
26static LIST_HEAD(nfs_automount_list);
27static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
28int nfs_mountpoint_expiry_timeout = 500 * HZ;
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50char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
51 unsigned flags)
52{
53 char *end;
54 int namelen;
55 unsigned seq;
56 const char *base;
57
58rename_retry:
59 end = buffer+buflen;
60 *--end = '\0';
61 buflen--;
62
63 seq = read_seqbegin(&rename_lock);
64 rcu_read_lock();
65 while (1) {
66 spin_lock(&dentry->d_lock);
67 if (IS_ROOT(dentry))
68 break;
69 namelen = dentry->d_name.len;
70 buflen -= namelen + 1;
71 if (buflen < 0)
72 goto Elong_unlock;
73 end -= namelen;
74 memcpy(end, dentry->d_name.name, namelen);
75 *--end = '/';
76 spin_unlock(&dentry->d_lock);
77 dentry = dentry->d_parent;
78 }
79 if (read_seqretry(&rename_lock, seq)) {
80 spin_unlock(&dentry->d_lock);
81 rcu_read_unlock();
82 goto rename_retry;
83 }
84 if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
85 if (--buflen < 0) {
86 spin_unlock(&dentry->d_lock);
87 rcu_read_unlock();
88 goto Elong;
89 }
90 *--end = '/';
91 }
92 *p = end;
93 base = dentry->d_fsdata;
94 if (!base) {
95 spin_unlock(&dentry->d_lock);
96 rcu_read_unlock();
97 WARN_ON(1);
98 return end;
99 }
100 namelen = strlen(base);
101 if (*end == '/') {
102
103 while (namelen > 0 && base[namelen - 1] == '/')
104 namelen--;
105 }
106 buflen -= namelen;
107 if (buflen < 0) {
108 spin_unlock(&dentry->d_lock);
109 rcu_read_unlock();
110 goto Elong;
111 }
112 end -= namelen;
113 memcpy(end, base, namelen);
114 spin_unlock(&dentry->d_lock);
115 rcu_read_unlock();
116 return end;
117Elong_unlock:
118 spin_unlock(&dentry->d_lock);
119 rcu_read_unlock();
120 if (read_seqretry(&rename_lock, seq))
121 goto rename_retry;
122Elong:
123 return ERR_PTR(-ENAMETOOLONG);
124}
125EXPORT_SYMBOL_GPL(nfs_path);
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139struct vfsmount *nfs_d_automount(struct path *path)
140{
141 struct vfsmount *mnt;
142 struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
143 struct nfs_fh *fh = NULL;
144 struct nfs_fattr *fattr = NULL;
145
146 if (IS_ROOT(path->dentry))
147 return ERR_PTR(-ESTALE);
148
149 mnt = ERR_PTR(-ENOMEM);
150 fh = nfs_alloc_fhandle();
151 fattr = nfs_alloc_fattr();
152 if (fh == NULL || fattr == NULL)
153 goto out;
154
155 mnt = server->nfs_client->rpc_ops->submount(server, path->dentry, fh, fattr);
156 if (IS_ERR(mnt))
157 goto out;
158
159 mntget(mnt);
160 mnt_set_expiry(mnt, &nfs_automount_list);
161 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
162
163out:
164 nfs_free_fattr(fattr);
165 nfs_free_fhandle(fh);
166 return mnt;
167}
168
169static int
170nfs_namespace_getattr(const struct path *path, struct kstat *stat,
171 u32 request_mask, unsigned int query_flags)
172{
173 if (NFS_FH(d_inode(path->dentry))->size != 0)
174 return nfs_getattr(path, stat, request_mask, query_flags);
175 generic_fillattr(d_inode(path->dentry), stat);
176 return 0;
177}
178
179static int
180nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
181{
182 if (NFS_FH(d_inode(dentry))->size != 0)
183 return nfs_setattr(dentry, attr);
184 return -EACCES;
185}
186
187const struct inode_operations nfs_mountpoint_inode_operations = {
188 .getattr = nfs_getattr,
189 .setattr = nfs_setattr,
190};
191
192const struct inode_operations nfs_referral_inode_operations = {
193 .getattr = nfs_namespace_getattr,
194 .setattr = nfs_namespace_setattr,
195};
196
197static void nfs_expire_automounts(struct work_struct *work)
198{
199 struct list_head *list = &nfs_automount_list;
200
201 mark_mounts_for_expiry(list);
202 if (!list_empty(list))
203 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
204}
205
206void nfs_release_automount_timer(void)
207{
208 if (list_empty(&nfs_automount_list))
209 cancel_delayed_work(&nfs_automount_task);
210}
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214
215static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
216 const char *devname,
217 struct nfs_clone_mount *mountdata)
218{
219 return vfs_submount(mountdata->dentry, &nfs_xdev_fs_type, devname, mountdata);
220}
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230struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
231 struct nfs_fattr *fattr, rpc_authflavor_t authflavor)
232{
233 struct nfs_clone_mount mountdata = {
234 .sb = dentry->d_sb,
235 .dentry = dentry,
236 .fh = fh,
237 .fattr = fattr,
238 .authflavor = authflavor,
239 };
240 struct vfsmount *mnt;
241 char *page = (char *) __get_free_page(GFP_USER);
242 char *devname;
243
244 if (page == NULL)
245 return ERR_PTR(-ENOMEM);
246
247 devname = nfs_devname(dentry, page, PAGE_SIZE);
248 if (IS_ERR(devname))
249 mnt = ERR_CAST(devname);
250 else
251 mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
252
253 free_page((unsigned long)page);
254 return mnt;
255}
256EXPORT_SYMBOL_GPL(nfs_do_submount);
257
258struct vfsmount *nfs_submount(struct nfs_server *server, struct dentry *dentry,
259 struct nfs_fh *fh, struct nfs_fattr *fattr)
260{
261 int err;
262 struct dentry *parent = dget_parent(dentry);
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265 err = server->nfs_client->rpc_ops->lookup(d_inode(parent), &dentry->d_name, fh, fattr, NULL);
266 dput(parent);
267 if (err != 0)
268 return ERR_PTR(err);
269
270 return nfs_do_submount(dentry, fh, fattr, server->client->cl_auth->au_flavor);
271}
272EXPORT_SYMBOL_GPL(nfs_submount);
273