blob: 1f063bacd2857caa119f4dce1bf429402b0be909 [file] [log] [blame]
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
Trond Myklebust55a97592006-06-09 09:34:19 -040010#include <linux/dcache.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090011#include <linux/gfp.h>
Trond Myklebust55a97592006-06-09 09:34:19 -040012#include <linux/mount.h>
13#include <linux/namei.h>
14#include <linux/nfs_fs.h>
15#include <linux/string.h>
16#include <linux/sunrpc/clnt.h>
17#include <linux/vfs.h>
Bryan Schumaker7ebb9312011-03-24 17:12:30 +000018#include <linux/sunrpc/gss_api.h>
David Howellsf7b422b2006-06-09 09:34:33 -040019#include "internal.h"
Trond Myklebust55a97592006-06-09 09:34:19 -040020
21#define NFSDBG_FACILITY NFSDBG_VFS
22
David Howells65f27f32006-11-22 14:55:48 +000023static void nfs_expire_automounts(struct work_struct *work);
David Howellsf7b422b2006-06-09 09:34:33 -040024
Adrian Bunka3dab292008-04-14 21:41:32 +030025static LIST_HEAD(nfs_automount_list);
David Howells65f27f32006-11-22 14:55:48 +000026static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
Trond Myklebust51d8fa62006-06-09 09:34:20 -040027int nfs_mountpoint_expiry_timeout = 500 * HZ;
28
Al Virof8ad9c42011-03-16 06:32:07 -040029static struct vfsmount *nfs_do_submount(struct dentry *dentry,
Adrian Bunk66f37502006-09-27 01:51:13 -070030 struct nfs_fh *fh,
Bryan Schumaker7ebb9312011-03-24 17:12:30 +000031 struct nfs_fattr *fattr,
32 rpc_authflavor_t authflavor);
Adrian Bunk66f37502006-09-27 01:51:13 -070033
Trond Myklebust55a97592006-06-09 09:34:19 -040034/*
David Howellsf7b422b2006-06-09 09:34:33 -040035 * nfs_path - reconstruct the path given an arbitrary dentry
Al Virob514f872011-03-16 06:26:11 -040036 * @base - used to return pointer to the end of devname part of path
David Howellsf7b422b2006-06-09 09:34:33 -040037 * @dentry - pointer to dentry
38 * @buffer - result buffer
39 * @buflen - length of buffer
40 *
Al Virob514f872011-03-16 06:26:11 -040041 * Helper function for constructing the server pathname
42 * by arbitrary hashed dentry.
David Howellsf7b422b2006-06-09 09:34:33 -040043 *
44 * This is mainly for use in figuring out the path on the
Al Virob514f872011-03-16 06:26:11 -040045 * server side when automounting on top of an existing partition
46 * and in generating /proc/mounts and friends.
David Howellsf7b422b2006-06-09 09:34:33 -040047 */
Al Virob514f872011-03-16 06:26:11 -040048char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen)
David Howellsf7b422b2006-06-09 09:34:33 -040049{
Nick Piggin949854d2011-01-07 17:49:37 +110050 char *end;
David Howellsf7b422b2006-06-09 09:34:33 -040051 int namelen;
Nick Piggin949854d2011-01-07 17:49:37 +110052 unsigned seq;
Al Virob514f872011-03-16 06:26:11 -040053 const char *base;
David Howellsf7b422b2006-06-09 09:34:33 -040054
Nick Piggin949854d2011-01-07 17:49:37 +110055rename_retry:
56 end = buffer+buflen;
David Howellsf7b422b2006-06-09 09:34:33 -040057 *--end = '\0';
58 buflen--;
Nick Piggin949854d2011-01-07 17:49:37 +110059
60 seq = read_seqbegin(&rename_lock);
61 rcu_read_lock();
Al Virob514f872011-03-16 06:26:11 -040062 while (1) {
63 spin_lock(&dentry->d_lock);
64 if (IS_ROOT(dentry))
65 break;
David Howellsf7b422b2006-06-09 09:34:33 -040066 namelen = dentry->d_name.len;
67 buflen -= namelen + 1;
68 if (buflen < 0)
Josh Triplettce510192006-07-24 16:30:00 -070069 goto Elong_unlock;
David Howellsf7b422b2006-06-09 09:34:33 -040070 end -= namelen;
71 memcpy(end, dentry->d_name.name, namelen);
72 *--end = '/';
Al Virob514f872011-03-16 06:26:11 -040073 spin_unlock(&dentry->d_lock);
David Howellsf7b422b2006-06-09 09:34:33 -040074 dentry = dentry->d_parent;
75 }
Al Virob514f872011-03-16 06:26:11 -040076 if (read_seqretry(&rename_lock, seq)) {
77 spin_unlock(&dentry->d_lock);
78 rcu_read_unlock();
Nick Piggin949854d2011-01-07 17:49:37 +110079 goto rename_retry;
Al Virob514f872011-03-16 06:26:11 -040080 }
Trond Myklebust0b75b352009-06-22 15:09:14 -040081 if (*end != '/') {
Al Virob514f872011-03-16 06:26:11 -040082 if (--buflen < 0) {
83 spin_unlock(&dentry->d_lock);
84 rcu_read_unlock();
Trond Myklebust0b75b352009-06-22 15:09:14 -040085 goto Elong;
Al Virob514f872011-03-16 06:26:11 -040086 }
Trond Myklebust0b75b352009-06-22 15:09:14 -040087 *--end = '/';
88 }
Al Virob514f872011-03-16 06:26:11 -040089 *p = end;
90 base = dentry->d_fsdata;
91 if (!base) {
92 spin_unlock(&dentry->d_lock);
93 rcu_read_unlock();
94 WARN_ON(1);
95 return end;
96 }
David Howellsf7b422b2006-06-09 09:34:33 -040097 namelen = strlen(base);
98 /* Strip off excess slashes in base string */
99 while (namelen > 0 && base[namelen - 1] == '/')
100 namelen--;
101 buflen -= namelen;
Al Virob514f872011-03-16 06:26:11 -0400102 if (buflen < 0) {
Dan Carpenter1c340922011-03-20 14:22:07 +0300103 spin_unlock(&dentry->d_lock);
Al Virob514f872011-03-16 06:26:11 -0400104 rcu_read_unlock();
David Howellsf7b422b2006-06-09 09:34:33 -0400105 goto Elong;
Al Virob514f872011-03-16 06:26:11 -0400106 }
David Howellsf7b422b2006-06-09 09:34:33 -0400107 end -= namelen;
108 memcpy(end, base, namelen);
Al Virob514f872011-03-16 06:26:11 -0400109 spin_unlock(&dentry->d_lock);
110 rcu_read_unlock();
David Howellsf7b422b2006-06-09 09:34:33 -0400111 return end;
Josh Triplettce510192006-07-24 16:30:00 -0700112Elong_unlock:
Dan Carpenter1c340922011-03-20 14:22:07 +0300113 spin_unlock(&dentry->d_lock);
Nick Piggin949854d2011-01-07 17:49:37 +1100114 rcu_read_unlock();
115 if (read_seqretry(&rename_lock, seq))
116 goto rename_retry;
David Howellsf7b422b2006-06-09 09:34:33 -0400117Elong:
118 return ERR_PTR(-ENAMETOOLONG);
119}
120
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000121#ifdef CONFIG_NFS_V4
Bryan Schumaker561f0b02011-04-12 08:47:15 -0400122static rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000123{
124 struct gss_api_mech *mech;
125 struct xdr_netobj oid;
126 int i;
127 rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;
128
129 for (i = 0; i < flavors->num_flavors; i++) {
130 struct nfs4_secinfo_flavor *flavor;
131 flavor = &flavors->flavors[i];
132
133 if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) {
134 pseudoflavor = flavor->flavor;
135 break;
136 } else if (flavor->flavor == RPC_AUTH_GSS) {
137 oid.len = flavor->gss.sec_oid4.len;
138 oid.data = flavor->gss.sec_oid4.data;
139 mech = gss_mech_get_by_OID(&oid);
140 if (!mech)
141 continue;
142 pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service);
143 gss_mech_put(mech);
144 break;
145 }
146 }
147
148 return pseudoflavor;
149}
150
Bryan Schumaker41887592011-04-06 14:33:28 -0400151static int nfs_negotiate_security(const struct dentry *parent,
152 const struct dentry *dentry,
153 rpc_authflavor_t *flavor)
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000154{
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000155 struct page *page;
156 struct nfs4_secinfo_flavors *flavors;
157 int (*secinfo)(struct inode *, const struct qstr *, struct nfs4_secinfo_flavors *);
Bryan Schumaker41887592011-04-06 14:33:28 -0400158 int ret = -EPERM;
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000159
160 secinfo = NFS_PROTO(parent->d_inode)->secinfo;
161 if (secinfo != NULL) {
162 page = alloc_page(GFP_KERNEL);
163 if (!page) {
Bryan Schumaker41887592011-04-06 14:33:28 -0400164 ret = -ENOMEM;
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000165 goto out;
166 }
167 flavors = page_address(page);
Bryan Schumaker41887592011-04-06 14:33:28 -0400168 ret = secinfo(parent->d_inode, &dentry->d_name, flavors);
Bryan Schumaker561f0b02011-04-12 08:47:15 -0400169 *flavor = nfs_find_best_sec(flavors);
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000170 put_page(page);
171 }
172
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000173out:
Bryan Schumaker41887592011-04-06 14:33:28 -0400174 return ret;
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000175}
176
Bryan Schumaker41887592011-04-06 14:33:28 -0400177static int nfs_lookup_with_sec(struct nfs_server *server, struct dentry *parent,
178 struct dentry *dentry, struct path *path,
179 struct nfs_fh *fh, struct nfs_fattr *fattr,
180 rpc_authflavor_t *flavor)
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000181{
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000182 struct rpc_clnt *clone;
183 struct rpc_auth *auth;
184 int err;
185
Bryan Schumaker41887592011-04-06 14:33:28 -0400186 err = nfs_negotiate_security(parent, path->dentry, flavor);
187 if (err < 0)
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000188 goto out;
189 clone = rpc_clone_client(server->client);
Bryan Schumaker41887592011-04-06 14:33:28 -0400190 auth = rpcauth_create(*flavor, clone);
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000191 if (!auth) {
Bryan Schumaker41887592011-04-06 14:33:28 -0400192 err = -EIO;
Trond Myklebusta0e7e3c2011-03-26 02:24:35 -0400193 goto out_shutdown;
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000194 }
195 err = server->nfs_client->rpc_ops->lookup(clone, parent->d_inode,
196 &path->dentry->d_name,
197 fh, fattr);
Trond Myklebusta0e7e3c2011-03-26 02:24:35 -0400198out_shutdown:
199 rpc_shutdown_client(clone);
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000200out:
Bryan Schumaker41887592011-04-06 14:33:28 -0400201 return err;
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000202}
203#else /* CONFIG_NFS_V4 */
Bryan Schumaker41887592011-04-06 14:33:28 -0400204static inline int nfs_lookup_with_sec(struct nfs_server *server,
205 struct dentry *parent, struct dentry *dentry,
206 struct path *path, struct nfs_fh *fh,
207 struct nfs_fattr *fattr,
208 rpc_authflavor_t *flavor)
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000209{
210 return -EPERM;
211}
212#endif /* CONFIG_NFS_V4 */
213
David Howellsf7b422b2006-06-09 09:34:33 -0400214/*
David Howells36d43a42011-01-14 18:45:42 +0000215 * nfs_d_automount - Handle crossing a mountpoint on the server
216 * @path - The mountpoint
Trond Myklebust55a97592006-06-09 09:34:19 -0400217 *
218 * When we encounter a mountpoint on the server, we want to set up
219 * a mountpoint on the client too, to prevent inode numbers from
220 * colliding, and to allow "df" to work properly.
221 * On NFSv4, we also want to allow for the fact that different
222 * filesystems may be migrated to different servers in a failover
223 * situation, and that different filesystems may want to use
224 * different security flavours.
225 */
David Howells36d43a42011-01-14 18:45:42 +0000226struct vfsmount *nfs_d_automount(struct path *path)
Trond Myklebust55a97592006-06-09 09:34:19 -0400227{
228 struct vfsmount *mnt;
David Howells36d43a42011-01-14 18:45:42 +0000229 struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
Trond Myklebust55a97592006-06-09 09:34:19 -0400230 struct dentry *parent;
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400231 struct nfs_fh *fh = NULL;
232 struct nfs_fattr *fattr = NULL;
Trond Myklebust55a97592006-06-09 09:34:19 -0400233 int err;
Bryan Schumaker41887592011-04-06 14:33:28 -0400234 rpc_authflavor_t flavor = RPC_AUTH_UNIX;
Trond Myklebust55a97592006-06-09 09:34:19 -0400235
David Howells36d43a42011-01-14 18:45:42 +0000236 dprintk("--> nfs_d_automount()\n");
David Howells54ceac42006-08-22 20:06:13 -0400237
David Howells36d43a42011-01-14 18:45:42 +0000238 mnt = ERR_PTR(-ESTALE);
239 if (IS_ROOT(path->dentry))
240 goto out_nofree;
Denis V. Lunev44d57592008-08-11 12:02:34 +0400241
David Howells36d43a42011-01-14 18:45:42 +0000242 mnt = ERR_PTR(-ENOMEM);
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400243 fh = nfs_alloc_fhandle();
244 fattr = nfs_alloc_fattr();
245 if (fh == NULL || fattr == NULL)
David Howells36d43a42011-01-14 18:45:42 +0000246 goto out;
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400247
Harvey Harrison3110ff82008-05-02 13:42:44 -0700248 dprintk("%s: enter\n", __func__);
David Howells54ceac42006-08-22 20:06:13 -0400249
David Howells36d43a42011-01-14 18:45:42 +0000250 /* Look it up again to get its attributes */
251 parent = dget_parent(path->dentry);
Bryan Schumaker7c513052011-03-24 17:12:24 +0000252 err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode,
David Howells36d43a42011-01-14 18:45:42 +0000253 &path->dentry->d_name,
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400254 fh, fattr);
Bryan Schumaker41887592011-04-06 14:33:28 -0400255 if (err == -EPERM && NFS_PROTO(parent->d_inode)->secinfo != NULL)
256 err = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr, &flavor);
Trond Myklebust55a97592006-06-09 09:34:19 -0400257 dput(parent);
David Howells36d43a42011-01-14 18:45:42 +0000258 if (err != 0) {
259 mnt = ERR_PTR(err);
260 goto out;
261 }
Trond Myklebust55a97592006-06-09 09:34:19 -0400262
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400263 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
Al Virof8ad9c42011-03-16 06:32:07 -0400264 mnt = nfs_do_refmount(path->dentry);
Manoj Naik6b97fd32006-06-09 09:34:29 -0400265 else
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000266 mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
Trond Myklebust55a97592006-06-09 09:34:19 -0400267 if (IS_ERR(mnt))
David Howells36d43a42011-01-14 18:45:42 +0000268 goto out;
Trond Myklebust55a97592006-06-09 09:34:19 -0400269
David Howellsea5b7782011-01-14 19:10:03 +0000270 dprintk("%s: done, success\n", __func__);
271 mntget(mnt); /* prevent immediate expiration */
272 mnt_set_expiry(mnt, &nfs_automount_list);
273 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
David Howells36d43a42011-01-14 18:45:42 +0000274
Trond Myklebust55a97592006-06-09 09:34:19 -0400275out:
Trond Myklebusta4d7f162010-04-16 16:22:46 -0400276 nfs_free_fattr(fattr);
277 nfs_free_fhandle(fh);
David Howells36d43a42011-01-14 18:45:42 +0000278out_nofree:
279 dprintk("<-- nfs_follow_mountpoint() = %p\n", mnt);
280 return mnt;
Trond Myklebust55a97592006-06-09 09:34:19 -0400281}
282
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800283const struct inode_operations nfs_mountpoint_inode_operations = {
Trond Myklebust55a97592006-06-09 09:34:19 -0400284 .getattr = nfs_getattr,
285};
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400286
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800287const struct inode_operations nfs_referral_inode_operations = {
Manoj Naik6b97fd32006-06-09 09:34:29 -0400288};
289
David Howells65f27f32006-11-22 14:55:48 +0000290static void nfs_expire_automounts(struct work_struct *work)
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400291{
David Howells65f27f32006-11-22 14:55:48 +0000292 struct list_head *list = &nfs_automount_list;
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400293
294 mark_mounts_for_expiry(list);
295 if (!list_empty(list))
296 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
297}
298
299void nfs_release_automount_timer(void)
300{
Trond Myklebust3d39c692007-08-07 15:28:33 -0400301 if (list_empty(&nfs_automount_list))
Trond Myklebust560aef72007-08-27 09:14:56 -0400302 cancel_delayed_work(&nfs_automount_task);
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400303}
David Howellsf7b422b2006-06-09 09:34:33 -0400304
305/*
306 * Clone a mountpoint of the appropriate type
307 */
David Howells509de812006-08-22 20:06:11 -0400308static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
309 const char *devname,
David Howellsf7b422b2006-06-09 09:34:33 -0400310 struct nfs_clone_mount *mountdata)
311{
312#ifdef CONFIG_NFS_V4
Denis V. Lunevfd08d7e2008-07-31 09:38:55 +0400313 struct vfsmount *mnt = ERR_PTR(-EINVAL);
Trond Myklebust40c553192007-12-14 14:56:07 -0500314 switch (server->nfs_client->rpc_ops->version) {
David Howellsf7b422b2006-06-09 09:34:33 -0400315 case 2:
316 case 3:
David Howells54ceac42006-08-22 20:06:13 -0400317 mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400318 break;
319 case 4:
David Howells54ceac42006-08-22 20:06:13 -0400320 mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400321 }
322 return mnt;
323#else
David Howells54ceac42006-08-22 20:06:13 -0400324 return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400325#endif
326}
327
328/**
329 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
David Howellsf7b422b2006-06-09 09:34:33 -0400330 * @dentry - parent directory
331 * @fh - filehandle for new root dentry
332 * @fattr - attributes for new root inode
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000333 * @authflavor - security flavor to use when performing the mount
David Howellsf7b422b2006-06-09 09:34:33 -0400334 *
335 */
Al Virof8ad9c42011-03-16 06:32:07 -0400336static struct vfsmount *nfs_do_submount(struct dentry *dentry,
Adrian Bunk66f37502006-09-27 01:51:13 -0700337 struct nfs_fh *fh,
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000338 struct nfs_fattr *fattr,
339 rpc_authflavor_t authflavor)
David Howellsf7b422b2006-06-09 09:34:33 -0400340{
341 struct nfs_clone_mount mountdata = {
Al Virof8ad9c42011-03-16 06:32:07 -0400342 .sb = dentry->d_sb,
David Howellsf7b422b2006-06-09 09:34:33 -0400343 .dentry = dentry,
344 .fh = fh,
345 .fattr = fattr,
Bryan Schumaker7ebb9312011-03-24 17:12:30 +0000346 .authflavor = authflavor,
David Howellsf7b422b2006-06-09 09:34:33 -0400347 };
348 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
349 char *page = (char *) __get_free_page(GFP_USER);
350 char *devname;
351
David Howells54ceac42006-08-22 20:06:13 -0400352 dprintk("--> nfs_do_submount()\n");
353
Harvey Harrison3110ff82008-05-02 13:42:44 -0700354 dprintk("%s: submounting on %s/%s\n", __func__,
David Howellsf7b422b2006-06-09 09:34:33 -0400355 dentry->d_parent->d_name.name,
356 dentry->d_name.name);
357 if (page == NULL)
358 goto out;
Al Virob514f872011-03-16 06:26:11 -0400359 devname = nfs_devname(dentry, page, PAGE_SIZE);
David Howellsf7b422b2006-06-09 09:34:33 -0400360 mnt = (struct vfsmount *)devname;
361 if (IS_ERR(devname))
362 goto free_page;
Al Virof8ad9c42011-03-16 06:32:07 -0400363 mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400364free_page:
365 free_page((unsigned long)page);
366out:
Harvey Harrison3110ff82008-05-02 13:42:44 -0700367 dprintk("%s: done\n", __func__);
David Howells54ceac42006-08-22 20:06:13 -0400368
369 dprintk("<-- nfs_do_submount() = %p\n", mnt);
David Howellsf7b422b2006-06-09 09:34:33 -0400370 return mnt;
371}