blob: ccd0b212e82a703b6ea1792339f7bf4603e5015f [file] [log] [blame]
David Howellsec268152007-04-26 15:49:28 -07001/* mountpoint management
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
3 * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/fs.h>
16#include <linux/pagemap.h>
17#include <linux/mount.h>
18#include <linux/namei.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090019#include <linux/gfp.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "internal.h"
21
22
23static struct dentry *afs_mntpt_lookup(struct inode *dir,
24 struct dentry *dentry,
Al Viro00cd8dd2012-06-10 17:13:09 -040025 unsigned int flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070026static int afs_mntpt_open(struct inode *inode, struct file *file);
David Howells08e0e7c2007-04-26 15:55:03 -070027static void afs_mntpt_expiry_timed_out(struct work_struct *work);
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -080029const struct file_operations afs_mntpt_file_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 .open = afs_mntpt_open,
Arnd Bergmann6038f372010-08-15 18:52:59 +020031 .llseek = noop_llseek,
Linus Torvalds1da177e2005-04-16 15:20:36 -070032};
33
Arjan van de Ven754661f2007-02-12 00:55:38 -080034const struct inode_operations afs_mntpt_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 .lookup = afs_mntpt_lookup,
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 .readlink = page_readlink,
David Howells416351f2007-05-09 02:33:45 -070037 .getattr = afs_getattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -070038};
39
wangleibec5eb62010-08-11 09:38:04 +010040const struct inode_operations afs_autocell_inode_operations = {
wangleibec5eb62010-08-11 09:38:04 +010041 .getattr = afs_getattr,
42};
43
Linus Torvalds1da177e2005-04-16 15:20:36 -070044static LIST_HEAD(afs_vfsmounts);
David Howells08e0e7c2007-04-26 15:55:03 -070045static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Adrian Bunkc1206a22007-10-16 23:26:41 -070047static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
Linus Torvalds1da177e2005-04-16 15:20:36 -070049/*
50 * check a symbolic link to see whether it actually encodes a mountpoint
51 * - sets the AFS_VNODE_MOUNTPOINT flag on the vnode appropriately
52 */
David Howells00d3b7a2007-04-26 15:57:07 -070053int afs_mntpt_check_symlink(struct afs_vnode *vnode, struct key *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -070054{
55 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 size_t size;
57 char *buf;
58 int ret;
59
David Howells416351f2007-05-09 02:33:45 -070060 _enter("{%x:%u,%u}",
61 vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 /* read the contents of the symlink into the pagecache */
Al Virof6d335c2010-05-21 15:27:09 +010064 page = read_cache_page(AFS_VNODE_TO_I(vnode)->i_mapping, 0,
65 afs_page_filler, key);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 if (IS_ERR(page)) {
67 ret = PTR_ERR(page);
68 goto out;
69 }
70
71 ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 if (PageError(page))
73 goto out_free;
74
Nick Piggin6fe69002007-05-06 14:49:04 -070075 buf = kmap(page);
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 /* examine the symlink's contents */
78 size = vnode->status.size;
David Howells08e0e7c2007-04-26 15:55:03 -070079 _debug("symlink to %*.*s", (int) size, (int) size, buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81 if (size > 2 &&
82 (buf[0] == '%' || buf[0] == '#') &&
83 buf[size - 1] == '.'
84 ) {
85 _debug("symlink is a mountpoint");
86 spin_lock(&vnode->lock);
David Howells08e0e7c2007-04-26 15:55:03 -070087 set_bit(AFS_VNODE_MOUNTPOINT, &vnode->flags);
David Howellsd18610b2011-01-14 19:04:05 +000088 vnode->vfs_inode.i_flags |= S_AUTOMOUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 spin_unlock(&vnode->lock);
90 }
91
92 ret = 0;
93
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 kunmap(page);
Nick Piggin6fe69002007-05-06 14:49:04 -070095out_free:
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 page_cache_release(page);
David Howellsec268152007-04-26 15:49:28 -070097out:
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 _leave(" = %d", ret);
99 return ret;
David Howellsec268152007-04-26 15:49:28 -0700100}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102/*
103 * no valid lookup procedure on this sort of dir
104 */
105static struct dentry *afs_mntpt_lookup(struct inode *dir,
106 struct dentry *dentry,
Al Viro00cd8dd2012-06-10 17:13:09 -0400107 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
Al Viroa4555892014-10-21 20:11:25 -0400109 _enter("%p,%p{%pd2}", dir, dentry, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 return ERR_PTR(-EREMOTE);
David Howellsec268152007-04-26 15:49:28 -0700111}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113/*
114 * no valid open procedure on this sort of dir
115 */
116static int afs_mntpt_open(struct inode *inode, struct file *file)
117{
Al Viroa4555892014-10-21 20:11:25 -0400118 _enter("%p,%p{%pD2}", inode, file, file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 return -EREMOTE;
David Howellsec268152007-04-26 15:49:28 -0700120}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122/*
123 * create a vfsmount to be automounted
124 */
125static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
126{
127 struct afs_super_info *super;
128 struct vfsmount *mnt;
wangleibec5eb62010-08-11 09:38:04 +0100129 struct afs_vnode *vnode;
David Howells083fd8b2010-04-21 12:01:23 +0100130 struct page *page;
wangleibec5eb62010-08-11 09:38:04 +0100131 char *devname, *options;
132 bool rwpath = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 int ret;
134
Al Viroa4555892014-10-21 20:11:25 -0400135 _enter("{%pd}", mntpt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
David Howells2b0143b2015-03-17 22:25:59 +0000137 BUG_ON(!d_inode(mntpt));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 ret = -ENOMEM;
140 devname = (char *) get_zeroed_page(GFP_KERNEL);
141 if (!devname)
David Howells083fd8b2010-04-21 12:01:23 +0100142 goto error_no_devname;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
144 options = (char *) get_zeroed_page(GFP_KERNEL);
145 if (!options)
David Howells083fd8b2010-04-21 12:01:23 +0100146 goto error_no_options;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
David Howells2b0143b2015-03-17 22:25:59 +0000148 vnode = AFS_FS_I(d_inode(mntpt));
wangleibec5eb62010-08-11 09:38:04 +0100149 if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
150 /* if the directory is a pseudo directory, use the d_name */
151 static const char afs_root_cell[] = ":root.cell.";
152 unsigned size = mntpt->d_name.len;
153
154 ret = -ENOENT;
155 if (size < 2 || size > AFS_MAXCELLNAME)
156 goto error_no_page;
157
158 if (mntpt->d_name.name[0] == '.') {
159 devname[0] = '#';
160 memcpy(devname + 1, mntpt->d_name.name, size - 1);
161 memcpy(devname + size, afs_root_cell,
162 sizeof(afs_root_cell));
163 rwpath = true;
164 } else {
165 devname[0] = '%';
166 memcpy(devname + 1, mntpt->d_name.name, size);
167 memcpy(devname + size + 1, afs_root_cell,
168 sizeof(afs_root_cell));
169 }
170 } else {
171 /* read the contents of the AFS special symlink */
David Howells2b0143b2015-03-17 22:25:59 +0000172 loff_t size = i_size_read(d_inode(mntpt));
wangleibec5eb62010-08-11 09:38:04 +0100173 char *buf;
174
175 ret = -EINVAL;
176 if (size > PAGE_SIZE - 1)
177 goto error_no_page;
178
David Howells2b0143b2015-03-17 22:25:59 +0000179 page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
wangleibec5eb62010-08-11 09:38:04 +0100180 if (IS_ERR(page)) {
181 ret = PTR_ERR(page);
182 goto error_no_page;
183 }
184
185 ret = -EIO;
186 if (PageError(page))
187 goto error;
188
Cong Wangda4aa362011-11-25 23:14:26 +0800189 buf = kmap_atomic(page);
wangleibec5eb62010-08-11 09:38:04 +0100190 memcpy(devname, buf, size);
Cong Wangda4aa362011-11-25 23:14:26 +0800191 kunmap_atomic(buf);
wangleibec5eb62010-08-11 09:38:04 +0100192 page_cache_release(page);
193 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 }
195
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 /* work out what options we want */
197 super = AFS_FS_S(mntpt->d_sb);
198 memcpy(options, "cell=", 5);
199 strcpy(options + 5, super->volume->cell->name);
wangleibec5eb62010-08-11 09:38:04 +0100200 if (super->volume->type == AFSVL_RWVOL || rwpath)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 strcat(options, ",rwpath");
202
203 /* try and do the mount */
David Howells08e0e7c2007-04-26 15:55:03 -0700204 _debug("--- attempting mount %s -o %s ---", devname, options);
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400205 mnt = vfs_kern_mount(&afs_fs_type, 0, devname, options);
David Howells08e0e7c2007-04-26 15:55:03 -0700206 _debug("--- mount result %p ---", mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
208 free_page((unsigned long) devname);
209 free_page((unsigned long) options);
David Howells08e0e7c2007-04-26 15:55:03 -0700210 _leave(" = %p", mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 return mnt;
212
David Howellsec268152007-04-26 15:49:28 -0700213error:
David Howells083fd8b2010-04-21 12:01:23 +0100214 page_cache_release(page);
215error_no_page:
216 free_page((unsigned long) options);
217error_no_options:
218 free_page((unsigned long) devname);
219error_no_devname:
David Howells08e0e7c2007-04-26 15:55:03 -0700220 _leave(" = %d", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 return ERR_PTR(ret);
David Howellsec268152007-04-26 15:49:28 -0700222}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224/*
David Howellsd18610b2011-01-14 19:04:05 +0000225 * handle an automount point
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 */
David Howellsd18610b2011-01-14 19:04:05 +0000227struct vfsmount *afs_d_automount(struct path *path)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228{
229 struct vfsmount *newmnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Al Viroa4555892014-10-21 20:11:25 -0400231 _enter("{%pd}", path->dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
David Howellsd18610b2011-01-14 19:04:05 +0000233 newmnt = afs_mntpt_do_automount(path->dentry);
234 if (IS_ERR(newmnt))
235 return newmnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
David Howellsea5b7782011-01-14 19:10:03 +0000237 mntget(newmnt); /* prevent immediate expiration */
238 mnt_set_expiry(newmnt, &afs_vfsmounts);
239 queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
240 afs_mntpt_expiry_timeout * HZ);
Al Viro5ffc2832011-11-25 02:22:06 -0500241 _leave(" = %p", newmnt);
David Howellsea5b7782011-01-14 19:10:03 +0000242 return newmnt;
David Howellsec268152007-04-26 15:49:28 -0700243}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245/*
246 * handle mountpoint expiry timer going off
247 */
David Howells08e0e7c2007-04-26 15:55:03 -0700248static void afs_mntpt_expiry_timed_out(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249{
David Howells08e0e7c2007-04-26 15:55:03 -0700250 _enter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
David Howells08e0e7c2007-04-26 15:55:03 -0700252 if (!list_empty(&afs_vfsmounts)) {
253 mark_mounts_for_expiry(&afs_vfsmounts);
Tejun Heo0ad53ee2011-01-14 15:56:37 +0000254 queue_delayed_work(afs_wq, &afs_mntpt_expiry_timer,
255 afs_mntpt_expiry_timeout * HZ);
David Howells08e0e7c2007-04-26 15:55:03 -0700256 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
David Howells08e0e7c2007-04-26 15:55:03 -0700258 _leave("");
259}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
David Howells08e0e7c2007-04-26 15:55:03 -0700261/*
262 * kill the AFS mountpoint timer if it's still running
263 */
264void afs_mntpt_kill_timer(void)
265{
266 _enter("");
267
268 ASSERT(list_empty(&afs_vfsmounts));
Tejun Heo0ad53ee2011-01-14 15:56:37 +0000269 cancel_delayed_work_sync(&afs_mntpt_expiry_timer);
David Howells08e0e7c2007-04-26 15:55:03 -0700270}