blob: 60408646176b9e7fdc1c9da0e7cc1c8986812024 [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
10#include <linux/config.h>
11
12#include <linux/dcache.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>
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
Trond Myklebust51d8fa62006-06-09 09:34:20 -040023static void nfs_expire_automounts(void *list);
David Howellsf7b422b2006-06-09 09:34:33 -040024
25LIST_HEAD(nfs_automount_list);
Trond Myklebust51d8fa62006-06-09 09:34:20 -040026static DECLARE_WORK(nfs_automount_task, nfs_expire_automounts, &nfs_automount_list);
27int nfs_mountpoint_expiry_timeout = 500 * HZ;
28
Adrian Bunk66f37502006-09-27 01:51:13 -070029static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
30 const struct dentry *dentry,
31 struct nfs_fh *fh,
32 struct nfs_fattr *fattr);
33
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
36 * @base - arbitrary string to prepend to the path
David Howells54ceac42006-08-22 20:06:13 -040037 * @droot - pointer to root dentry for mountpoint
David Howellsf7b422b2006-06-09 09:34:33 -040038 * @dentry - pointer to dentry
39 * @buffer - result buffer
40 * @buflen - length of buffer
41 *
42 * Helper function for constructing the path from the
43 * root dentry to an arbitrary hashed dentry.
44 *
45 * This is mainly for use in figuring out the path on the
46 * server side when automounting on top of an existing partition.
47 */
David Howells54ceac42006-08-22 20:06:13 -040048char *nfs_path(const char *base,
49 const struct dentry *droot,
50 const struct dentry *dentry,
David Howellsf7b422b2006-06-09 09:34:33 -040051 char *buffer, ssize_t buflen)
52{
53 char *end = buffer+buflen;
54 int namelen;
55
56 *--end = '\0';
57 buflen--;
58 spin_lock(&dcache_lock);
David Howells54ceac42006-08-22 20:06:13 -040059 while (!IS_ROOT(dentry) && dentry != droot) {
David Howellsf7b422b2006-06-09 09:34:33 -040060 namelen = dentry->d_name.len;
61 buflen -= namelen + 1;
62 if (buflen < 0)
Josh Triplettce510192006-07-24 16:30:00 -070063 goto Elong_unlock;
David Howellsf7b422b2006-06-09 09:34:33 -040064 end -= namelen;
65 memcpy(end, dentry->d_name.name, namelen);
66 *--end = '/';
67 dentry = dentry->d_parent;
68 }
69 spin_unlock(&dcache_lock);
70 namelen = strlen(base);
71 /* Strip off excess slashes in base string */
72 while (namelen > 0 && base[namelen - 1] == '/')
73 namelen--;
74 buflen -= namelen;
75 if (buflen < 0)
76 goto Elong;
77 end -= namelen;
78 memcpy(end, base, namelen);
79 return end;
Josh Triplettce510192006-07-24 16:30:00 -070080Elong_unlock:
81 spin_unlock(&dcache_lock);
David Howellsf7b422b2006-06-09 09:34:33 -040082Elong:
83 return ERR_PTR(-ENAMETOOLONG);
84}
85
86/*
Trond Myklebust55a97592006-06-09 09:34:19 -040087 * nfs_follow_mountpoint - handle crossing a mountpoint on the server
88 * @dentry - dentry of mountpoint
89 * @nd - nameidata info
90 *
91 * When we encounter a mountpoint on the server, we want to set up
92 * a mountpoint on the client too, to prevent inode numbers from
93 * colliding, and to allow "df" to work properly.
94 * On NFSv4, we also want to allow for the fact that different
95 * filesystems may be migrated to different servers in a failover
96 * situation, and that different filesystems may want to use
97 * different security flavours.
98 */
99static void * nfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
100{
101 struct vfsmount *mnt;
102 struct nfs_server *server = NFS_SERVER(dentry->d_inode);
103 struct dentry *parent;
104 struct nfs_fh fh;
105 struct nfs_fattr fattr;
106 int err;
107
David Howells54ceac42006-08-22 20:06:13 -0400108 dprintk("--> nfs_follow_mountpoint()\n");
109
Trond Myklebust55a97592006-06-09 09:34:19 -0400110 BUG_ON(IS_ROOT(dentry));
111 dprintk("%s: enter\n", __FUNCTION__);
112 dput(nd->dentry);
113 nd->dentry = dget(dentry);
David Howells54ceac42006-08-22 20:06:13 -0400114
Trond Myklebust55a97592006-06-09 09:34:19 -0400115 /* Look it up again */
116 parent = dget_parent(nd->dentry);
David Howells8fa5c002006-08-22 20:06:12 -0400117 err = server->nfs_client->rpc_ops->lookup(parent->d_inode,
118 &nd->dentry->d_name,
119 &fh, &fattr);
Trond Myklebust55a97592006-06-09 09:34:19 -0400120 dput(parent);
121 if (err != 0)
122 goto out_err;
123
Manoj Naik6b97fd32006-06-09 09:34:29 -0400124 if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL)
125 mnt = nfs_do_refmount(nd->mnt, nd->dentry);
126 else
127 mnt = nfs_do_submount(nd->mnt, nd->dentry, &fh, &fattr);
Trond Myklebust55a97592006-06-09 09:34:19 -0400128 err = PTR_ERR(mnt);
129 if (IS_ERR(mnt))
130 goto out_err;
131
132 mntget(mnt);
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400133 err = do_add_mount(mnt, nd, nd->mnt->mnt_flags|MNT_SHRINKABLE, &nfs_automount_list);
Trond Myklebust55a97592006-06-09 09:34:19 -0400134 if (err < 0) {
135 mntput(mnt);
136 if (err == -EBUSY)
137 goto out_follow;
138 goto out_err;
139 }
140 mntput(nd->mnt);
141 dput(nd->dentry);
142 nd->mnt = mnt;
143 nd->dentry = dget(mnt->mnt_root);
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400144 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
Trond Myklebust55a97592006-06-09 09:34:19 -0400145out:
146 dprintk("%s: done, returned %d\n", __FUNCTION__, err);
David Howells54ceac42006-08-22 20:06:13 -0400147
148 dprintk("<-- nfs_follow_mountpoint() = %d\n", err);
Trond Myklebust55a97592006-06-09 09:34:19 -0400149 return ERR_PTR(err);
150out_err:
151 path_release(nd);
152 goto out;
153out_follow:
154 while(d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
155 ;
156 err = 0;
157 goto out;
158}
159
160struct inode_operations nfs_mountpoint_inode_operations = {
161 .follow_link = nfs_follow_mountpoint,
162 .getattr = nfs_getattr,
163};
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400164
Manoj Naik6b97fd32006-06-09 09:34:29 -0400165struct inode_operations nfs_referral_inode_operations = {
166 .follow_link = nfs_follow_mountpoint,
167};
168
Trond Myklebust51d8fa62006-06-09 09:34:20 -0400169static void nfs_expire_automounts(void *data)
170{
171 struct list_head *list = (struct list_head *)data;
172
173 mark_mounts_for_expiry(list);
174 if (!list_empty(list))
175 schedule_delayed_work(&nfs_automount_task, nfs_mountpoint_expiry_timeout);
176}
177
178void nfs_release_automount_timer(void)
179{
180 if (list_empty(&nfs_automount_list)) {
181 cancel_delayed_work(&nfs_automount_task);
182 flush_scheduled_work();
183 }
184}
David Howellsf7b422b2006-06-09 09:34:33 -0400185
186/*
187 * Clone a mountpoint of the appropriate type
188 */
David Howells509de812006-08-22 20:06:11 -0400189static struct vfsmount *nfs_do_clone_mount(struct nfs_server *server,
190 const char *devname,
David Howellsf7b422b2006-06-09 09:34:33 -0400191 struct nfs_clone_mount *mountdata)
192{
193#ifdef CONFIG_NFS_V4
194 struct vfsmount *mnt = NULL;
David Howells8fa5c002006-08-22 20:06:12 -0400195 switch (server->nfs_client->cl_nfsversion) {
David Howellsf7b422b2006-06-09 09:34:33 -0400196 case 2:
197 case 3:
David Howells54ceac42006-08-22 20:06:13 -0400198 mnt = vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400199 break;
200 case 4:
David Howells54ceac42006-08-22 20:06:13 -0400201 mnt = vfs_kern_mount(&nfs4_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400202 }
203 return mnt;
204#else
David Howells54ceac42006-08-22 20:06:13 -0400205 return vfs_kern_mount(&nfs_xdev_fs_type, 0, devname, mountdata);
David Howellsf7b422b2006-06-09 09:34:33 -0400206#endif
207}
208
209/**
210 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
211 * @mnt_parent - mountpoint of parent directory
212 * @dentry - parent directory
213 * @fh - filehandle for new root dentry
214 * @fattr - attributes for new root inode
215 *
216 */
Adrian Bunk66f37502006-09-27 01:51:13 -0700217static struct vfsmount *nfs_do_submount(const struct vfsmount *mnt_parent,
218 const struct dentry *dentry,
219 struct nfs_fh *fh,
220 struct nfs_fattr *fattr)
David Howellsf7b422b2006-06-09 09:34:33 -0400221{
222 struct nfs_clone_mount mountdata = {
223 .sb = mnt_parent->mnt_sb,
224 .dentry = dentry,
225 .fh = fh,
226 .fattr = fattr,
227 };
228 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
229 char *page = (char *) __get_free_page(GFP_USER);
230 char *devname;
231
David Howells54ceac42006-08-22 20:06:13 -0400232 dprintk("--> nfs_do_submount()\n");
233
David Howellsf7b422b2006-06-09 09:34:33 -0400234 dprintk("%s: submounting on %s/%s\n", __FUNCTION__,
235 dentry->d_parent->d_name.name,
236 dentry->d_name.name);
237 if (page == NULL)
238 goto out;
239 devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);
240 mnt = (struct vfsmount *)devname;
241 if (IS_ERR(devname))
242 goto free_page;
243 mnt = nfs_do_clone_mount(NFS_SB(mnt_parent->mnt_sb), devname, &mountdata);
244free_page:
245 free_page((unsigned long)page);
246out:
247 dprintk("%s: done\n", __FUNCTION__);
David Howells54ceac42006-08-22 20:06:13 -0400248
249 dprintk("<-- nfs_do_submount() = %p\n", mnt);
David Howellsf7b422b2006-06-09 09:34:33 -0400250 return mnt;
251}