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Trond Myklebust55a97592006-06-09 09:34:19 -04001/*
2 * linux/fs/nfs/namespace.c
3 *
4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
David Howells54ceac42006-08-22 20:06:13 -04005 * - Modified by David Howells <dhowells@redhat.com>
Trond Myklebust55a97592006-06-09 09:34:19 -04006 *
7 * NFS namespace
8 */
9
Bryan Schumakerddda8e02012-07-30 16:05:23 -040010#include <linux/module.h>
Trond Myklebust55a97592006-06-09 09:34:19 -040011#include <linux/dcache.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090012#include <linux/gfp.h>
Trond Myklebust55a97592006-06-09 09:34:19 -040013#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>
Bryan Schumaker7ebb9312011-03-24 17:12:30 +000019#include <linux/sunrpc/gss_api.h>
David Howellsf7b422b2006-06-09 09:34:33 -040020#include "internal.h"
Trond Myklebust55a97592006-06-09 09:34:19 -040021
22#define NFSDBG_FACILITY NFSDBG_VFS
23
David Howells65f27f32006-11-22 14:55:48 +000024static void nfs_expire_automounts(struct work_struct *work);
David Howellsf7b422b2006-06-09 09:34:33 -040025
Adrian Bunka3dab292008-04-14 21:41:32 +030026static LIST_HEAD(nfs_automount_list);
David Howells65f27f32006-11-22 14:55:48 +000027static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
Trond Myklebust51d8fa62006-06-09 09:34:20 -040028int nfs_mountpoint_expiry_timeout = 500 * HZ;
29
Trond Myklebust55a97592006-06-09 09:34:19 -040030/*
David Howellsf7b422b2006-06-09 09:34:33 -040031 * nfs_path - reconstruct the path given an arbitrary dentry
Al Virob514f872011-03-16 06:26:11 -040032 * @base - used to return pointer to the end of devname part of path
David Howellsf7b422b2006-06-09 09:34:33 -040033 * @dentry - pointer to dentry
34 * @buffer - result buffer
35 * @buflen - length of buffer
Ben Hutchings97a54862012-10-21 19:23:52 +010036 * @flags - options (see below)
David Howellsf7b422b2006-06-09 09:34:33 -040037 *
Al Virob514f872011-03-16 06:26:11 -040038 * Helper function for constructing the server pathname
39 * by arbitrary hashed dentry.
David Howellsf7b422b2006-06-09 09:34:33 -040040 *
41 * This is mainly for use in figuring out the path on the
Al Virob514f872011-03-16 06:26:11 -040042 * server side when automounting on top of an existing partition
43 * and in generating /proc/mounts and friends.
Ben Hutchings97a54862012-10-21 19:23:52 +010044 *
45 * Supported flags:
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)
David Howellsf7b422b2006-06-09 09:34:33 -040049 */
Ben Hutchings97a54862012-10-21 19:23:52 +010050char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
51 unsigned flags)
David Howellsf7b422b2006-06-09 09:34:33 -040052{
Nick Piggin949854d2011-01-07 17:49:37 +110053 char *end;
David Howellsf7b422b2006-06-09 09:34:33 -040054 int namelen;
Nick Piggin949854d2011-01-07 17:49:37 +110055 unsigned seq;
Al Virob514f872011-03-16 06:26:11 -040056 const char *base;
David Howellsf7b422b2006-06-09 09:34:33 -040057
Nick Piggin949854d2011-01-07 17:49:37 +110058rename_retry:
59 end = buffer+buflen;
David Howellsf7b422b2006-06-09 09:34:33 -040060 *--end = '\0';
61 buflen--;
Nick Piggin949854d2011-01-07 17:49:37 +110062
63 seq = read_seqbegin(&rename_lock);
64 rcu_read_lock();
Al Virob514f872011-03-16 06:26:11 -040065 while (1) {
66 spin_lock(&dentry->d_lock);
67 if (IS_ROOT(dentry))
68 break;
David Howellsf7b422b2006-06-09 09:34:33 -040069 namelen = dentry->d_name.len;
70 buflen -= namelen + 1;
71 if (buflen < 0)
Josh Triplettce510192006-07-24 16:30:00 -070072 goto Elong_unlock;
David Howellsf7b422b2006-06-09 09:34:33 -040073 end -= namelen;
74 memcpy(end, dentry->d_name.name, namelen);
75 *--end = '/';
Al Virob514f872011-03-16 06:26:11 -040076 spin_unlock(&dentry->d_lock);
David Howellsf7b422b2006-06-09 09:34:33 -040077 dentry = dentry->d_parent;
78 }
Al Virob514f872011-03-16 06:26:11 -040079 if (read_seqretry(&rename_lock, seq)) {
80 spin_unlock(&dentry->d_lock);
81 rcu_read_unlock();
Nick Piggin949854d2011-01-07 17:49:37 +110082 goto rename_retry;
Al Virob514f872011-03-16 06:26:11 -040083 }
Ben Hutchings97a54862012-10-21 19:23:52 +010084 if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
Al Virob514f872011-03-16 06:26:11 -040085 if (--buflen < 0) {
86 spin_unlock(&dentry->d_lock);
87 rcu_read_unlock();
Trond Myklebust0b75b352009-06-22 15:09:14 -040088 goto Elong;
Al Virob514f872011-03-16 06:26:11 -040089 }
Trond Myklebust0b75b352009-06-22 15:09:14 -040090 *--end = '/';
91 }
Al Virob514f872011-03-16 06:26:11 -040092 *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 }
David Howellsf7b422b2006-06-09 09:34:33 -0400100 namelen = strlen(base);
Ben Hutchings97a54862012-10-21 19:23:52 +0100101 if (flags & NFS_PATH_CANONICAL) {
102 /* Strip off excess slashes in base string */
103 while (namelen > 0 && base[namelen - 1] == '/')
104 namelen--;
105 }
David Howellsf7b422b2006-06-09 09:34:33 -0400106 buflen -= namelen;
Al Virob514f872011-03-16 06:26:11 -0400107 if (buflen < 0) {
Dan Carpenter1c340922011-03-20 14:22:07 +0300108 spin_unlock(&dentry->d_lock);
Al Virob514f872011-03-16 06:26:11 -0400109 rcu_read_unlock();
David Howellsf7b422b2006-06-09 09:34:33 -0400110 goto Elong;
Al Virob514f872011-03-16 06:26:11 -0400111 }
David Howellsf7b422b2006-06-09 09:34:33 -0400112 end -= namelen;
113 memcpy(end, base, namelen);
Al Virob514f872011-03-16 06:26:11 -0400114 spin_unlock(&dentry->d_lock);
115 rcu_read_unlock();
David Howellsf7b422b2006-06-09 09:34:33 -0400116 return end;
Josh Triplettce510192006-07-24 16:30:00 -0700117Elong_unlock:
Dan Carpenter1c340922011-03-20 14:22:07 +0300118 spin_unlock(&dentry->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +1100119 rcu_read_unlock();
120 if (read_seqretry(&rename_lock, seq))
121 goto rename_retry;
David Howellsf7b422b2006-06-09 09:34:33 -0400122Elong:
123 return ERR_PTR(-ENAMETOOLONG);
124}
Bryan Schumaker89d77c82012-07-30 16:05:25 -0400125EXPORT_SYMBOL_GPL(nfs_path);
David Howellsf7b422b2006-06-09 09:34:33 -0400126
127/*
David Howells36d43a42011-01-14 18:45:42 +0000128 * nfs_d_automount - Handle crossing a mountpoint on the server
129 * @path - The mountpoint
Trond Myklebust55a97592006-06-09 09:34:19 -0400130 *
131 * When we encounter a mountpoint on the server, we want to set up
132 * a mountpoint on the client too, to prevent inode numbers from
133 * colliding, and to allow "df" to work properly.
134 * On NFSv4, we also want to allow for the fact that different
135 * filesystems may be migrated to different servers in a failover
136 * situation, and that different filesystems may want to use
137 * different security flavours.
138 */
David Howells36d43a42011-01-14 18:45:42 +0000139struct vfsmount *nfs_d_automount(struct path *path)
Trond Myklebust55a97592006-06-09 09:34:19 -0400140{
141 struct vfsmount *mnt;
Bryan Schumaker281cad42012-04-27 13:27:45 -0400142 struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400143 struct nfs_fh *fh = NULL;
144 struct nfs_fattr *fattr = NULL;
Trond Myklebust55a97592006-06-09 09:34:19 -0400145
David Howells36d43a42011-01-14 18:45:42 +0000146 dprintk("--> nfs_d_automount()\n");
David Howells54ceac42006-08-22 20:06:13 -0400147
David Howells36d43a42011-01-14 18:45:42 +0000148 mnt = ERR_PTR(-ESTALE);
149 if (IS_ROOT(path->dentry))
150 goto out_nofree;
Denis V. Lunev44d57592008-08-11 12:02:34 +0400151
David Howells36d43a42011-01-14 18:45:42 +0000152 mnt = ERR_PTR(-ENOMEM);
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400153 fh = nfs_alloc_fhandle();
154 fattr = nfs_alloc_fattr();
155 if (fh == NULL || fattr == NULL)
David Howells36d43a42011-01-14 18:45:42 +0000156 goto out;
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400157
Harvey Harrison3110ff82008-05-02 13:42:44 -0700158 dprintk("%s: enter\n", __func__);
David Howells54ceac42006-08-22 20:06:13 -0400159
Bryan Schumaker281cad42012-04-27 13:27:45 -0400160 mnt = server->nfs_client->rpc_ops->submount(server, path->dentry, fh, fattr);
Trond Myklebust55a97592006-06-09 09:34:19 -0400161 if (IS_ERR(mnt))
David Howells36d43a42011-01-14 18:45:42 +0000162 goto out;
Trond Myklebust55a97592006-06-09 09:34:19 -0400163
David Howellsea5b7782011-01-14 19:10:03 +0000164 dprintk("%s: done, success\n", __func__);
165 mntget(mnt); /* prevent immediate expiration */
166 mnt_set_expiry(mnt, &nfs_automount_list);
167 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
David Howells36d43a42011-01-14 18:45:42 +0000168
Trond Myklebust55a97592006-06-09 09:34:19 -0400169out:
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400170 nfs_free_fattr(fattr);
171 nfs_free_fhandle(fh);
David Howells36d43a42011-01-14 18:45:42 +0000172out_nofree:
Chuck Leverd7c32672012-02-15 16:35:17 -0500173 if (IS_ERR(mnt))
174 dprintk("<-- %s(): error %ld\n", __func__, PTR_ERR(mnt));
175 else
176 dprintk("<-- %s() = %p\n", __func__, mnt);
David Howells36d43a42011-01-14 18:45:42 +0000177 return mnt;
Trond Myklebust55a97592006-06-09 09:34:19 -0400178}
179
Trond Myklebustab225412013-01-22 00:17:06 -0500180static int
181nfs_namespace_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
182{
183 if (NFS_FH(dentry->d_inode)->size != 0)
184 return nfs_getattr(mnt, dentry, stat);
185 generic_fillattr(dentry->d_inode, stat);
186 return 0;
187}
188
189static int
190nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
191{
192 if (NFS_FH(dentry->d_inode)->size != 0)
193 return nfs_setattr(dentry, attr);
194 return -EACCES;
195}
196
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800197const struct inode_operations nfs_mountpoint_inode_operations = {
Trond Myklebust55a97592006-06-09 09:34:19 -0400198 .getattr = nfs_getattr,
Trond Myklebustab225412013-01-22 00:17:06 -0500199 .setattr = nfs_setattr,
Trond Myklebust55a97592006-06-09 09:34:19 -0400200};
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400201
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800202const struct inode_operations nfs_referral_inode_operations = {
Trond Myklebustab225412013-01-22 00:17:06 -0500203 .getattr = nfs_namespace_getattr,
204 .setattr = nfs_namespace_setattr,
Manoj Naik6b97fd32006-06-09 09:34:29 -0400205};
206
David Howells65f27f32006-11-22 14:55:48 +0000207static void nfs_expire_automounts(struct work_struct *work)
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400208{
David Howells65f27f32006-11-22 14:55:48 +0000209 struct list_head *list = &nfs_automount_list;
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400210
211 mark_mounts_for_expiry(list);
212 if (!list_empty(list))
213 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
214}
215
216void nfs_release_automount_timer(void)
217{
Trond Myklebust3d39c692007-08-07 15:28:33 -0400218 if (list_empty(&nfs_automount_list))
Trond Myklebust560aef72007-08-27 09:14:56 -0400219 cancel_delayed_work(&nfs_automount_task);
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400220}
David Howellsf7b422b2006-06-09 09:34:33 -0400221
222/*
223 * Clone a mountpoint of the appropriate type
224 */
David Howells509de812006-08-22 20:06:11 -0400225static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
226 const char *devname,
David Howellsf7b422b2006-06-09 09:34:33 -0400227 struct nfs_clone_mount *mountdata)
228{
David Howells54ceac42006-08-22 20:06:13 -0400229 return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400230}
231
232/**
233 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
David Howellsf7b422b2006-06-09 09:34:33 -0400234 * @dentry - parent directory
235 * @fh - filehandle for new root dentry
236 * @fattr - attributes for new root inode
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000237 * @authflavor - security flavor to use when performing the mount
David Howellsf7b422b2006-06-09 09:34:33 -0400238 *
239 */
Bryan Schumaker281cad42012-04-27 13:27:45 -0400240struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh,
241 struct nfs_fattr *fattr, rpc_authflavor_t authflavor)
David Howellsf7b422b2006-06-09 09:34:33 -0400242{
243 struct nfs_clone_mount mountdata = {
Al Virof8ad9c42011-03-16 06:32:07 -0400244 .sb = dentry->d_sb,
David Howellsf7b422b2006-06-09 09:34:33 -0400245 .dentry = dentry,
246 .fh = fh,
247 .fattr = fattr,
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000248 .authflavor = authflavor,
David Howellsf7b422b2006-06-09 09:34:33 -0400249 };
250 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
251 char *page = (char *) __get_free_page(GFP_USER);
252 char *devname;
253
David Howells54ceac42006-08-22 20:06:13 -0400254 dprintk("--> nfs_do_submount()\n");
255
Harvey Harrison3110ff82008-05-02 13:42:44 -0700256 dprintk("%s: submounting on %s/%s\n", __func__,
David Howellsf7b422b2006-06-09 09:34:33 -0400257 dentry->d_parent->d_name.name,
258 dentry->d_name.name);
259 if (page == NULL)
260 goto out;
Al Virob514f872011-03-16 06:26:11 -0400261 devname = nfs_devname(dentry, page, PAGE_SIZE);
David Howellsf7b422b2006-06-09 09:34:33 -0400262 mnt = (struct vfsmount *)devname;
263 if (IS_ERR(devname))
264 goto free_page;
Al Virof8ad9c42011-03-16 06:32:07 -0400265 mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400266free_page:
267 free_page((unsigned long)page);
268out:
Harvey Harrison3110ff82008-05-02 13:42:44 -0700269 dprintk("%s: done\n", __func__);
David Howells54ceac42006-08-22 20:06:13 -0400270
271 dprintk("<-- nfs_do_submount() = %p\n", mnt);
David Howellsf7b422b2006-06-09 09:34:33 -0400272 return mnt;
273}
Bryan Schumaker89d77c82012-07-30 16:05:25 -0400274EXPORT_SYMBOL_GPL(nfs_do_submount);
Bryan Schumaker281cad42012-04-27 13:27:45 -0400275
276struct vfsmount *nfs_submount(struct nfs_server *server, struct dentry *dentry,
277 struct nfs_fh *fh, struct nfs_fattr *fattr)
278{
279 int err;
280 struct dentry *parent = dget_parent(dentry);
281
282 /* Look it up again to get its attributes */
David Quigley1775fd32013-05-22 12:50:42 -0400283 err = server->nfs_client->rpc_ops->lookup(parent->d_inode, &dentry->d_name, fh, fattr, NULL);
Bryan Schumaker281cad42012-04-27 13:27:45 -0400284 dput(parent);
285 if (err != 0)
286 return ERR_PTR(err);
287
288 return nfs_do_submount(dentry, fh, fattr, server->client->cl_auth->au_flavor);
289}
Bryan Schumakerddda8e02012-07-30 16:05:23 -0400290EXPORT_SYMBOL_GPL(nfs_submount);