blob: d8e6d421c27fb74eed07369e83278183bb394f82 [file] [log] [blame]
Ian Kente9a7c2f2016-03-15 14:58:25 -07001/*
2 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
3 * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
4 * Copyright 2001-2006 Ian Kent <raven@themaw.net>
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
6 * This file is part of the Linux kernel and is made available under
7 * the terms of the GNU General Public License, version 2, or at your
8 * option, any later version, incorporated herein by reference.
Ian Kente9a7c2f2016-03-15 14:58:25 -07009 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070010
11#include "autofs_i.h"
12
13static unsigned long now;
14
Ian Kent1f5f2c32006-03-27 01:14:44 -080015/* Check if a dentry can be expired */
Linus Torvalds1da177e2005-04-16 15:20:36 -070016static inline int autofs4_can_expire(struct dentry *dentry,
Ian Kente9a7c2f2016-03-15 14:58:25 -070017 unsigned long timeout, int do_now)
Linus Torvalds1da177e2005-04-16 15:20:36 -070018{
19 struct autofs_info *ino = autofs4_dentry_ino(dentry);
20
21 /* dentry in the process of being deleted */
22 if (ino == NULL)
23 return 0;
24
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 if (!do_now) {
26 /* Too young to die */
Ian Kentc0ba7e52006-09-25 16:24:16 -070027 if (!timeout || time_after(ino->last_used + timeout, now))
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 return 1;
31}
32
Ian Kent1f5f2c32006-03-27 01:14:44 -080033/* Check a mount point for busyness */
34static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035{
Ian Kente0a7aae2006-03-27 01:14:47 -080036 struct dentry *top = dentry;
Al Viro9393bd02009-04-18 13:58:15 -040037 struct path path = {.mnt = mnt, .dentry = dentry};
Ian Kent1f5f2c32006-03-27 01:14:44 -080038 int status = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Ian Kent8a78d592016-03-15 14:58:45 -070040 pr_debug("dentry %p %pd\n", dentry, dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
Al Viro9393bd02009-04-18 13:58:15 -040042 path_get(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
David Howellscc53ce52011-01-14 18:45:26 +000044 if (!follow_down_one(&path))
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 goto done;
46
Al Viro9393bd02009-04-18 13:58:15 -040047 if (is_autofs4_dentry(path.dentry)) {
48 struct autofs_sb_info *sbi = autofs4_sbi(path.dentry->d_sb);
Ian Kentbc9c4062008-11-06 12:53:22 -080049
50 /* This is an autofs submount, we can't expire it */
Ian Kenta92daf62009-01-06 14:42:08 -080051 if (autofs_type_indirect(sbi->type))
Ian Kentbc9c4062008-11-06 12:53:22 -080052 goto done;
Ian Kentbc9c4062008-11-06 12:53:22 -080053 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
Ian Kente0a7aae2006-03-27 01:14:47 -080055 /* Update the expiry counter if fs is busy */
Ian Kent37d08922009-09-01 11:26:22 +080056 if (!may_umount_tree(path.mnt)) {
Ian Kente9a7c2f2016-03-15 14:58:25 -070057 struct autofs_info *ino;
58
59 ino = autofs4_dentry_ino(top);
Ian Kente0a7aae2006-03-27 01:14:47 -080060 ino->last_used = jiffies;
61 goto done;
62 }
63
64 status = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065done:
Ian Kent8a78d592016-03-15 14:58:45 -070066 pr_debug("returning = %d\n", status);
Al Viro9393bd02009-04-18 13:58:15 -040067 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 return status;
69}
70
Ian Kent1ce12ba2006-03-27 01:14:45 -080071/*
Ian Kentd4a85e32011-03-25 01:51:20 +080072 * Calculate and dget next entry in the subdirs list under root.
73 */
74static struct dentry *get_next_positive_subdir(struct dentry *prev,
Ian Kente9a7c2f2016-03-15 14:58:25 -070075 struct dentry *root)
Ian Kentd4a85e32011-03-25 01:51:20 +080076{
Ian Kente7854722011-03-25 01:51:31 +080077 struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
Ian Kentd4a85e32011-03-25 01:51:20 +080078 struct list_head *next;
Ian Kenta45440f2012-08-06 09:37:47 +080079 struct dentry *q;
Ian Kentd4a85e32011-03-25 01:51:20 +080080
Ian Kente7854722011-03-25 01:51:31 +080081 spin_lock(&sbi->lookup_lock);
Ian Kenta45440f2012-08-06 09:37:47 +080082 spin_lock(&root->d_lock);
Ian Kentd4a85e32011-03-25 01:51:20 +080083
Ian Kenta45440f2012-08-06 09:37:47 +080084 if (prev)
Al Viro946e51f2014-10-26 19:19:16 -040085 next = prev->d_child.next;
Ian Kenta45440f2012-08-06 09:37:47 +080086 else {
Ian Kentd4a85e32011-03-25 01:51:20 +080087 prev = dget_dlock(root);
88 next = prev->d_subdirs.next;
Ian Kentd4a85e32011-03-25 01:51:20 +080089 }
90
Ian Kenta45440f2012-08-06 09:37:47 +080091cont:
Ian Kentd4a85e32011-03-25 01:51:20 +080092 if (next == &root->d_subdirs) {
Ian Kenta45440f2012-08-06 09:37:47 +080093 spin_unlock(&root->d_lock);
Ian Kente7854722011-03-25 01:51:31 +080094 spin_unlock(&sbi->lookup_lock);
Ian Kentd4a85e32011-03-25 01:51:20 +080095 dput(prev);
96 return NULL;
97 }
98
Al Viro946e51f2014-10-26 19:19:16 -040099 q = list_entry(next, struct dentry, d_child);
Ian Kentd4a85e32011-03-25 01:51:20 +0800100
101 spin_lock_nested(&q->d_lock, DENTRY_D_LOCK_NESTED);
Ian Kenta45440f2012-08-06 09:37:47 +0800102 /* Already gone or negative dentry (under construction) - try next */
Al Viro84d08fa2013-07-05 18:59:33 +0400103 if (!d_count(q) || !simple_positive(q)) {
Ian Kenta45440f2012-08-06 09:37:47 +0800104 spin_unlock(&q->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400105 next = q->d_child.next;
Ian Kenta45440f2012-08-06 09:37:47 +0800106 goto cont;
Ian Kentd4a85e32011-03-25 01:51:20 +0800107 }
108 dget_dlock(q);
109 spin_unlock(&q->d_lock);
Ian Kenta45440f2012-08-06 09:37:47 +0800110 spin_unlock(&root->d_lock);
Ian Kente7854722011-03-25 01:51:31 +0800111 spin_unlock(&sbi->lookup_lock);
Ian Kentd4a85e32011-03-25 01:51:20 +0800112
113 dput(prev);
114
115 return q;
116}
117
118/*
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100119 * Calculate and dget next entry in top down tree traversal.
Ian Kent1ce12ba2006-03-27 01:14:45 -0800120 */
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100121static struct dentry *get_next_positive_dentry(struct dentry *prev,
Ian Kente9a7c2f2016-03-15 14:58:25 -0700122 struct dentry *root)
Ian Kent1ce12ba2006-03-27 01:14:45 -0800123{
Ian Kente7854722011-03-25 01:51:31 +0800124 struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100125 struct list_head *next;
126 struct dentry *p, *ret;
Ian Kent1ce12ba2006-03-27 01:14:45 -0800127
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100128 if (prev == NULL)
Ian Kentc14cc632011-01-18 12:06:04 +0800129 return dget(root);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100130
Ian Kente7854722011-03-25 01:51:31 +0800131 spin_lock(&sbi->lookup_lock);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100132relock:
133 p = prev;
134 spin_lock(&p->d_lock);
135again:
136 next = p->d_subdirs.next;
Ian Kent1ce12ba2006-03-27 01:14:45 -0800137 if (next == &p->d_subdirs) {
138 while (1) {
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100139 struct dentry *parent;
140
141 if (p == root) {
142 spin_unlock(&p->d_lock);
Ian Kente7854722011-03-25 01:51:31 +0800143 spin_unlock(&sbi->lookup_lock);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100144 dput(prev);
Ian Kent1ce12ba2006-03-27 01:14:45 -0800145 return NULL;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100146 }
147
148 parent = p->d_parent;
149 if (!spin_trylock(&parent->d_lock)) {
150 spin_unlock(&p->d_lock);
151 cpu_relax();
152 goto relock;
153 }
154 spin_unlock(&p->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400155 next = p->d_child.next;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100156 p = parent;
157 if (next != &parent->d_subdirs)
Ian Kent1ce12ba2006-03-27 01:14:45 -0800158 break;
Ian Kent1ce12ba2006-03-27 01:14:45 -0800159 }
160 }
Al Viro946e51f2014-10-26 19:19:16 -0400161 ret = list_entry(next, struct dentry, d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100162
163 spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
164 /* Negative dentry - try next */
165 if (!simple_positive(ret)) {
Ian Kentc14cc632011-01-18 12:06:04 +0800166 spin_unlock(&p->d_lock);
Steven Rostedt1d6f2092011-08-22 11:52:28 +0800167 lock_set_subclass(&ret->d_lock.dep_map, 0, _RET_IP_);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100168 p = ret;
169 goto again;
170 }
171 dget_dlock(ret);
172 spin_unlock(&ret->d_lock);
173 spin_unlock(&p->d_lock);
Ian Kente7854722011-03-25 01:51:31 +0800174 spin_unlock(&sbi->lookup_lock);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100175
176 dput(prev);
177
178 return ret;
Ian Kent1ce12ba2006-03-27 01:14:45 -0800179}
180
Ian Kent3a15e2a2006-03-27 01:14:55 -0800181/*
182 * Check a direct mount point for busyness.
183 * Direct mounts have similar expiry semantics to tree mounts.
184 * The tree is not busy iff no mountpoints are busy and there are no
185 * autofs submounts.
186 */
187static int autofs4_direct_busy(struct vfsmount *mnt,
Ian Kente9a7c2f2016-03-15 14:58:25 -0700188 struct dentry *top,
189 unsigned long timeout,
190 int do_now)
Ian Kent3a15e2a2006-03-27 01:14:55 -0800191{
Ian Kent8a78d592016-03-15 14:58:45 -0700192 pr_debug("top %p %pd\n", top, top);
Ian Kent3a15e2a2006-03-27 01:14:55 -0800193
Ian Kent3a15e2a2006-03-27 01:14:55 -0800194 /* If it's busy update the expiry counters */
195 if (!may_umount_tree(mnt)) {
Ian Kente9a7c2f2016-03-15 14:58:25 -0700196 struct autofs_info *ino;
197
198 ino = autofs4_dentry_ino(top);
Ian Kent3a15e2a2006-03-27 01:14:55 -0800199 if (ino)
200 ino->last_used = jiffies;
201 return 1;
202 }
203
204 /* Timeout of a direct mount is determined by its top dentry */
205 if (!autofs4_can_expire(top, timeout, do_now))
206 return 1;
207
208 return 0;
209}
210
Ian Kente9a7c2f2016-03-15 14:58:25 -0700211/*
212 * Check a directory tree of mount points for busyness
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 * The tree is not busy iff no mountpoints are busy
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 */
Ian Kent1f5f2c32006-03-27 01:14:44 -0800215static int autofs4_tree_busy(struct vfsmount *mnt,
216 struct dentry *top,
217 unsigned long timeout,
218 int do_now)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
Ian Kente0a7aae2006-03-27 01:14:47 -0800220 struct autofs_info *top_ino = autofs4_dentry_ino(top);
Ian Kent1ce12ba2006-03-27 01:14:45 -0800221 struct dentry *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
Ian Kent8a78d592016-03-15 14:58:45 -0700223 pr_debug("top %p %pd\n", top, top);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
225 /* Negative dentry - give up */
226 if (!simple_positive(top))
Ian Kent1f5f2c32006-03-27 01:14:44 -0800227 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100229 p = NULL;
230 while ((p = get_next_positive_dentry(p, top))) {
Ian Kent8a78d592016-03-15 14:58:45 -0700231 pr_debug("dentry %p %pd\n", p, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
Ian Kent1aff3c82006-03-27 01:14:46 -0800233 /*
234 * Is someone visiting anywhere in the subtree ?
235 * If there's no mount we need to check the usage
236 * count for the autofs dentry.
Ian Kente0a7aae2006-03-27 01:14:47 -0800237 * If the fs is busy update the expiry counter.
Ian Kent1aff3c82006-03-27 01:14:46 -0800238 */
Ian Kent1ce12ba2006-03-27 01:14:45 -0800239 if (d_mountpoint(p)) {
Ian Kent1ce12ba2006-03-27 01:14:45 -0800240 if (autofs4_mount_busy(mnt, p)) {
Ian Kente0a7aae2006-03-27 01:14:47 -0800241 top_ino->last_used = jiffies;
Ian Kent1ce12ba2006-03-27 01:14:45 -0800242 dput(p);
Ian Kent1f5f2c32006-03-27 01:14:44 -0800243 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 }
Ian Kent1aff3c82006-03-27 01:14:46 -0800245 } else {
Ian Kente0a7aae2006-03-27 01:14:47 -0800246 struct autofs_info *ino = autofs4_dentry_ino(p);
Ian Kent1aff3c82006-03-27 01:14:46 -0800247 unsigned int ino_count = atomic_read(&ino->count);
248
249 /* allow for dget above and top is already dgot */
250 if (p == top)
251 ino_count += 2;
252 else
253 ino_count++;
254
Al Viro84d08fa2013-07-05 18:59:33 +0400255 if (d_count(p) > ino_count) {
Ian Kente0a7aae2006-03-27 01:14:47 -0800256 top_ino->last_used = jiffies;
Ian Kent1aff3c82006-03-27 01:14:46 -0800257 dput(p);
258 return 1;
259 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 }
Ian Kent1aff3c82006-03-27 01:14:46 -0800262
263 /* Timeout of a tree mount is ultimately determined by its top dentry */
264 if (!autofs4_can_expire(top, timeout, do_now))
265 return 1;
266
Ian Kent1f5f2c32006-03-27 01:14:44 -0800267 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268}
269
270static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
271 struct dentry *parent,
272 unsigned long timeout,
273 int do_now)
274{
Ian Kent1ce12ba2006-03-27 01:14:45 -0800275 struct dentry *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
Ian Kent8a78d592016-03-15 14:58:45 -0700277 pr_debug("parent %p %pd\n", parent, parent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100279 p = NULL;
280 while ((p = get_next_positive_dentry(p, parent))) {
Ian Kent8a78d592016-03-15 14:58:45 -0700281 pr_debug("dentry %p %pd\n", p, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282
Ian Kent1ce12ba2006-03-27 01:14:45 -0800283 if (d_mountpoint(p)) {
Ian Kente0a7aae2006-03-27 01:14:47 -0800284 /* Can we umount this guy */
285 if (autofs4_mount_busy(mnt, p))
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100286 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
Ian Kente0a7aae2006-03-27 01:14:47 -0800288 /* Can we expire this guy */
289 if (autofs4_can_expire(p, timeout, do_now))
Ian Kent1ce12ba2006-03-27 01:14:45 -0800290 return p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 return NULL;
294}
295
Ian Kent3a15e2a2006-03-27 01:14:55 -0800296/* Check if we can expire a direct mount (possibly a tree) */
Ian Kent8d7b48e2008-10-15 22:02:54 -0700297struct dentry *autofs4_expire_direct(struct super_block *sb,
298 struct vfsmount *mnt,
299 struct autofs_sb_info *sbi,
300 int how)
Ian Kent3a15e2a2006-03-27 01:14:55 -0800301{
302 unsigned long timeout;
303 struct dentry *root = dget(sb->s_root);
304 int do_now = how & AUTOFS_EXP_IMMEDIATE;
Ian Kentb5b80172011-01-14 18:46:03 +0000305 struct autofs_info *ino;
Ian Kent3a15e2a2006-03-27 01:14:55 -0800306
Ian Kentc0ba7e52006-09-25 16:24:16 -0700307 if (!root)
Ian Kent3a15e2a2006-03-27 01:14:55 -0800308 return NULL;
309
310 now = jiffies;
311 timeout = sbi->exp_timeout;
312
Ian Kent3a15e2a2006-03-27 01:14:55 -0800313 spin_lock(&sbi->fs_lock);
Ian Kentb5b80172011-01-14 18:46:03 +0000314 ino = autofs4_dentry_ino(root);
315 /* No point expiring a pending mount */
Ian Kentf9398c22011-03-25 01:51:14 +0800316 if (ino->flags & AUTOFS_INF_PENDING)
317 goto out;
Ian Kent3a15e2a2006-03-27 01:14:55 -0800318 if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
Al Viroea01a182016-06-12 11:24:46 -0400319 ino->flags |= AUTOFS_INF_WANT_EXPIRE;
Ian Kent3a15e2a2006-03-27 01:14:55 -0800320 spin_unlock(&sbi->fs_lock);
NeilBrown4d885f92014-10-13 15:52:20 -0700321 synchronize_rcu();
322 spin_lock(&sbi->fs_lock);
323 if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
324 ino->flags |= AUTOFS_INF_EXPIRING;
NeilBrown4d885f92014-10-13 15:52:20 -0700325 init_completion(&ino->expire_complete);
326 spin_unlock(&sbi->fs_lock);
327 return root;
328 }
Al Viroea01a182016-06-12 11:24:46 -0400329 ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
Ian Kent3a15e2a2006-03-27 01:14:55 -0800330 }
Ian Kentf9398c22011-03-25 01:51:14 +0800331out:
Ian Kent3a15e2a2006-03-27 01:14:55 -0800332 spin_unlock(&sbi->fs_lock);
333 dput(root);
334
335 return NULL;
336}
337
NeilBrowna5d1dba2014-10-13 15:52:16 -0700338/* Check if 'dentry' should expire, or return a nearby
339 * dentry that is suitable.
340 * If returned dentry is different from arg dentry,
341 * then a dget() reference was taken, else not.
342 */
343static struct dentry *should_expire(struct dentry *dentry,
344 struct vfsmount *mnt,
345 unsigned long timeout,
346 int how)
347{
348 int do_now = how & AUTOFS_EXP_IMMEDIATE;
349 int exp_leaves = how & AUTOFS_EXP_LEAVES;
350 struct autofs_info *ino = autofs4_dentry_ino(dentry);
351 unsigned int ino_count;
352
353 /* No point expiring a pending mount */
354 if (ino->flags & AUTOFS_INF_PENDING)
355 return NULL;
356
357 /*
358 * Case 1: (i) indirect mount or top level pseudo direct mount
359 * (autofs-4.1).
360 * (ii) indirect mount with offset mount, check the "/"
361 * offset (autofs-5.0+).
362 */
363 if (d_mountpoint(dentry)) {
Ian Kent8a78d592016-03-15 14:58:45 -0700364 pr_debug("checking mountpoint %p %pd\n", dentry, dentry);
NeilBrowna5d1dba2014-10-13 15:52:16 -0700365
366 /* Can we umount this guy */
367 if (autofs4_mount_busy(mnt, dentry))
368 return NULL;
369
370 /* Can we expire this guy */
371 if (autofs4_can_expire(dentry, timeout, do_now))
372 return dentry;
373 return NULL;
374 }
375
David Howells2b0143b2015-03-17 22:25:59 +0000376 if (d_really_is_positive(dentry) && d_is_symlink(dentry)) {
Ian Kent8a78d592016-03-15 14:58:45 -0700377 pr_debug("checking symlink %p %pd\n", dentry, dentry);
NeilBrowna5d1dba2014-10-13 15:52:16 -0700378 /*
379 * A symlink can't be "busy" in the usual sense so
380 * just check last used for expire timeout.
381 */
382 if (autofs4_can_expire(dentry, timeout, do_now))
383 return dentry;
384 return NULL;
385 }
386
387 if (simple_empty(dentry))
388 return NULL;
389
390 /* Case 2: tree mount, expire iff entire tree is not busy */
391 if (!exp_leaves) {
392 /* Path walk currently on this dentry? */
393 ino_count = atomic_read(&ino->count) + 1;
394 if (d_count(dentry) > ino_count)
395 return NULL;
396
397 if (!autofs4_tree_busy(mnt, dentry, timeout, do_now))
398 return dentry;
399 /*
400 * Case 3: pseudo direct mount, expire individual leaves
401 * (autofs-4.1).
402 */
403 } else {
404 /* Path walk currently on this dentry? */
405 struct dentry *expired;
Ian Kente9a7c2f2016-03-15 14:58:25 -0700406
NeilBrowna5d1dba2014-10-13 15:52:16 -0700407 ino_count = atomic_read(&ino->count) + 1;
408 if (d_count(dentry) > ino_count)
409 return NULL;
410
411 expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
412 if (expired) {
413 if (expired == dentry)
414 dput(dentry);
415 return expired;
416 }
417 }
418 return NULL;
419}
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700420
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421/*
422 * Find an eligible tree to time-out
423 * A tree is eligible if :-
424 * - it is unused by any user process
425 * - it has been unused for exp_timeout time
426 */
Ian Kent8d7b48e2008-10-15 22:02:54 -0700427struct dentry *autofs4_expire_indirect(struct super_block *sb,
428 struct vfsmount *mnt,
429 struct autofs_sb_info *sbi,
430 int how)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431{
432 unsigned long timeout;
433 struct dentry *root = sb->s_root;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100434 struct dentry *dentry;
NeilBrowna5d1dba2014-10-13 15:52:16 -0700435 struct dentry *expired;
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700436 struct dentry *found;
Ian Kent97e74492008-07-23 21:30:26 -0700437 struct autofs_info *ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438
Ian Kentc0ba7e52006-09-25 16:24:16 -0700439 if (!root)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 return NULL;
441
442 now = jiffies;
443 timeout = sbi->exp_timeout;
444
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100445 dentry = NULL;
Ian Kentd4a85e32011-03-25 01:51:20 +0800446 while ((dentry = get_next_positive_subdir(dentry, root))) {
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700447 int flags = how;
448
Ian Kent97e74492008-07-23 21:30:26 -0700449 spin_lock(&sbi->fs_lock);
NeilBrown4d885f92014-10-13 15:52:20 -0700450 ino = autofs4_dentry_ino(dentry);
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700451 if (ino->flags & AUTOFS_INF_WANT_EXPIRE) {
NeilBrown4d885f92014-10-13 15:52:20 -0700452 spin_unlock(&sbi->fs_lock);
453 continue;
454 }
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700455 spin_unlock(&sbi->fs_lock);
456
457 expired = should_expire(dentry, mnt, timeout, flags);
458 if (!expired)
459 continue;
460
461 spin_lock(&sbi->fs_lock);
NeilBrown4d885f92014-10-13 15:52:20 -0700462 ino = autofs4_dentry_ino(expired);
Al Viroea01a182016-06-12 11:24:46 -0400463 ino->flags |= AUTOFS_INF_WANT_EXPIRE;
NeilBrown4d885f92014-10-13 15:52:20 -0700464 spin_unlock(&sbi->fs_lock);
465 synchronize_rcu();
NeilBrown4d885f92014-10-13 15:52:20 -0700466
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700467 /* Make sure a reference is not taken on found if
468 * things have changed.
469 */
470 flags &= ~AUTOFS_EXP_LEAVES;
471 found = should_expire(expired, mnt, timeout, how);
472 if (!found || found != expired)
473 /* Something has changed, continue */
474 goto next;
475
476 if (expired != dentry)
477 dput(dentry);
478
479 spin_lock(&sbi->fs_lock);
480 goto found;
481next:
482 spin_lock(&sbi->fs_lock);
Al Viroea01a182016-06-12 11:24:46 -0400483 ino->flags &= ~AUTOFS_INF_WANT_EXPIRE;
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700484 spin_unlock(&sbi->fs_lock);
NeilBrown4d885f92014-10-13 15:52:20 -0700485 if (expired != dentry)
486 dput(expired);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 return NULL;
Ian Kentafec5702008-05-01 04:35:06 -0700489
490found:
Ian Kent8a78d592016-03-15 14:58:45 -0700491 pr_debug("returning %p %pd\n", expired, expired);
Ian Kent97e74492008-07-23 21:30:26 -0700492 ino->flags |= AUTOFS_INF_EXPIRING;
Ian Kent6e60a9a2008-07-23 21:30:27 -0700493 init_completion(&ino->expire_complete);
Ian Kent97e74492008-07-23 21:30:26 -0700494 spin_unlock(&sbi->fs_lock);
Ian Kentafec5702008-05-01 04:35:06 -0700495 return expired;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496}
497
NeilBrown23bfc2a2014-10-13 15:52:14 -0700498int autofs4_expire_wait(struct dentry *dentry, int rcu_walk)
Ian Kent06a35982008-07-23 21:30:28 -0700499{
500 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
501 struct autofs_info *ino = autofs4_dentry_ino(dentry);
502 int status;
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700503 int state;
Ian Kent06a35982008-07-23 21:30:28 -0700504
505 /* Block on any pending expire */
Al Viroea01a182016-06-12 11:24:46 -0400506 if (!(ino->flags & AUTOFS_INF_WANT_EXPIRE))
NeilBrown4d885f92014-10-13 15:52:20 -0700507 return 0;
508 if (rcu_walk)
509 return -ECHILD;
510
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700511retry:
Ian Kent06a35982008-07-23 21:30:28 -0700512 spin_lock(&sbi->fs_lock);
Ian Kent7cbdb4a2016-09-19 14:44:12 -0700513 state = ino->flags & (AUTOFS_INF_WANT_EXPIRE | AUTOFS_INF_EXPIRING);
514 if (state == AUTOFS_INF_WANT_EXPIRE) {
515 spin_unlock(&sbi->fs_lock);
516 /*
517 * Possibly being selected for expire, wait until
518 * it's selected or not.
519 */
520 schedule_timeout_uninterruptible(HZ/10);
521 goto retry;
522 }
523 if (state & AUTOFS_INF_EXPIRING) {
Ian Kent06a35982008-07-23 21:30:28 -0700524 spin_unlock(&sbi->fs_lock);
525
Ian Kent8a78d592016-03-15 14:58:45 -0700526 pr_debug("waiting for expire %p name=%pd\n", dentry, dentry);
Ian Kent06a35982008-07-23 21:30:28 -0700527
528 status = autofs4_wait(sbi, dentry, NFY_NONE);
529 wait_for_completion(&ino->expire_complete);
530
Ian Kent8a78d592016-03-15 14:58:45 -0700531 pr_debug("expire done status=%d\n", status);
Ian Kent06a35982008-07-23 21:30:28 -0700532
Al Viro4b1ae272010-03-03 12:58:31 -0500533 if (d_unhashed(dentry))
Ian Kent06a35982008-07-23 21:30:28 -0700534 return -EAGAIN;
535
536 return status;
537 }
538 spin_unlock(&sbi->fs_lock);
539
540 return 0;
541}
542
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543/* Perform an expiry operation */
544int autofs4_expire_run(struct super_block *sb,
Ian Kente9a7c2f2016-03-15 14:58:25 -0700545 struct vfsmount *mnt,
546 struct autofs_sb_info *sbi,
547 struct autofs_packet_expire __user *pkt_p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548{
549 struct autofs_packet_expire pkt;
Ian Kent97e74492008-07-23 21:30:26 -0700550 struct autofs_info *ino;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 struct dentry *dentry;
Ian Kent97e74492008-07-23 21:30:26 -0700552 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553
Ian Kente9a7c2f2016-03-15 14:58:25 -0700554 memset(&pkt, 0, sizeof(pkt));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555
556 pkt.hdr.proto_version = sbi->version;
557 pkt.hdr.type = autofs_ptype_expire;
558
Ian Kente9a7c2f2016-03-15 14:58:25 -0700559 dentry = autofs4_expire_indirect(sb, mnt, sbi, 0);
560 if (!dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 return -EAGAIN;
562
563 pkt.len = dentry->d_name.len;
564 memcpy(pkt.name, dentry->d_name.name, pkt.len);
565 pkt.name[pkt.len] = '\0';
566 dput(dentry);
567
Ian Kente9a7c2f2016-03-15 14:58:25 -0700568 if (copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)))
Ian Kent97e74492008-07-23 21:30:26 -0700569 ret = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570
Ian Kent97e74492008-07-23 21:30:26 -0700571 spin_lock(&sbi->fs_lock);
572 ino = autofs4_dentry_ino(dentry);
NeilBrown6ece08e2014-10-13 15:52:18 -0700573 /* avoid rapid-fire expire attempts if expiry fails */
574 ino->last_used = now;
Al Viroea01a182016-06-12 11:24:46 -0400575 ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE);
Ian Kent6e60a9a2008-07-23 21:30:27 -0700576 complete_all(&ino->expire_complete);
Ian Kent97e74492008-07-23 21:30:26 -0700577 spin_unlock(&sbi->fs_lock);
578
579 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580}
581
Ian Kent56fcef72009-03-31 15:24:43 -0700582int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
583 struct autofs_sb_info *sbi, int when)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584{
585 struct dentry *dentry;
586 int ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587
Ian Kenta92daf62009-01-06 14:42:08 -0800588 if (autofs_type_trigger(sbi->type))
Ian Kent56fcef72009-03-31 15:24:43 -0700589 dentry = autofs4_expire_direct(sb, mnt, sbi, when);
Ian Kent3a15e2a2006-03-27 01:14:55 -0800590 else
Ian Kent56fcef72009-03-31 15:24:43 -0700591 dentry = autofs4_expire_indirect(sb, mnt, sbi, when);
Ian Kent3a15e2a2006-03-27 01:14:55 -0800592
593 if (dentry) {
Ian Kent1f5f2c32006-03-27 01:14:44 -0800594 struct autofs_info *ino = autofs4_dentry_ino(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595
596 /* This is synchronous because it makes the daemon a
Ian Kente9a7c2f2016-03-15 14:58:25 -0700597 * little easier
598 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
Ian Kent6e60a9a2008-07-23 21:30:27 -0700600
Ian Kent97e74492008-07-23 21:30:26 -0700601 spin_lock(&sbi->fs_lock);
NeilBrown6ece08e2014-10-13 15:52:18 -0700602 /* avoid rapid-fire expire attempts if expiry fails */
603 ino->last_used = now;
Al Viroea01a182016-06-12 11:24:46 -0400604 ino->flags &= ~(AUTOFS_INF_EXPIRING|AUTOFS_INF_WANT_EXPIRE);
Ian Kent6e60a9a2008-07-23 21:30:27 -0700605 complete_all(&ino->expire_complete);
Ian Kent97e74492008-07-23 21:30:26 -0700606 spin_unlock(&sbi->fs_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 dput(dentry);
608 }
Ian Kent1f5f2c32006-03-27 01:14:44 -0800609
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 return ret;
611}
612
Ian Kente9a7c2f2016-03-15 14:58:25 -0700613/*
614 * Call repeatedly until it returns -EAGAIN, meaning there's nothing
615 * more to be done.
616 */
Ian Kent56fcef72009-03-31 15:24:43 -0700617int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
618 struct autofs_sb_info *sbi, int __user *arg)
619{
620 int do_now = 0;
621
622 if (arg && get_user(do_now, arg))
623 return -EFAULT;
624
625 return autofs4_do_expire_multi(sb, mnt, sbi, do_now);
626}
627