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15#include "autofs_i.h"
16
17static unsigned long now;
18
19
20static inline int autofs4_can_expire(struct dentry *dentry,
21 unsigned long timeout, int do_now)
22{
23 struct autofs_info *ino = autofs4_dentry_ino(dentry);
24
25
26 if (ino == NULL)
27 return 0;
28
29 if (!do_now) {
30
31 if (!timeout || time_after(ino->last_used + timeout, now))
32 return 0;
33
34
35
36
37
38 ino->last_used = now;
39 }
40 return 1;
41}
42
43
44static int autofs4_mount_busy(struct vfsmount *mnt, struct dentry *dentry)
45{
46 struct dentry *top = dentry;
47 struct path path = {.mnt = mnt, .dentry = dentry};
48 int status = 1;
49
50 DPRINTK("dentry %p %.*s",
51 dentry, (int)dentry->d_name.len, dentry->d_name.name);
52
53 path_get(&path);
54
55 if (!follow_down_one(&path))
56 goto done;
57
58 if (is_autofs4_dentry(path.dentry)) {
59 struct autofs_sb_info *sbi = autofs4_sbi(path.dentry->d_sb);
60
61
62 if (autofs_type_indirect(sbi->type))
63 goto done;
64 }
65
66
67 if (!may_umount_tree(path.mnt)) {
68 struct autofs_info *ino = autofs4_dentry_ino(top);
69 ino->last_used = jiffies;
70 goto done;
71 }
72
73 status = 0;
74done:
75 DPRINTK("returning = %d", status);
76 path_put(&path);
77 return status;
78}
79
80
81
82
83static struct dentry *get_next_positive_subdir(struct dentry *prev,
84 struct dentry *root)
85{
86 struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
87 struct list_head *next;
88 struct dentry *q;
89
90 spin_lock(&sbi->lookup_lock);
91 spin_lock(&root->d_lock);
92
93 if (prev)
94 next = prev->d_u.d_child.next;
95 else {
96 prev = dget_dlock(root);
97 next = prev->d_subdirs.next;
98 }
99
100cont:
101 if (next == &root->d_subdirs) {
102 spin_unlock(&root->d_lock);
103 spin_unlock(&sbi->lookup_lock);
104 dput(prev);
105 return NULL;
106 }
107
108 q = list_entry(next, struct dentry, d_u.d_child);
109
110 spin_lock_nested(&q->d_lock, DENTRY_D_LOCK_NESTED);
111
112 if (!d_count(q) || !simple_positive(q)) {
113 spin_unlock(&q->d_lock);
114 next = q->d_u.d_child.next;
115 goto cont;
116 }
117 dget_dlock(q);
118 spin_unlock(&q->d_lock);
119 spin_unlock(&root->d_lock);
120 spin_unlock(&sbi->lookup_lock);
121
122 dput(prev);
123
124 return q;
125}
126
127
128
129
130static struct dentry *get_next_positive_dentry(struct dentry *prev,
131 struct dentry *root)
132{
133 struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
134 struct list_head *next;
135 struct dentry *p, *ret;
136
137 if (prev == NULL)
138 return dget(root);
139
140 spin_lock(&sbi->lookup_lock);
141relock:
142 p = prev;
143 spin_lock(&p->d_lock);
144again:
145 next = p->d_subdirs.next;
146 if (next == &p->d_subdirs) {
147 while (1) {
148 struct dentry *parent;
149
150 if (p == root) {
151 spin_unlock(&p->d_lock);
152 spin_unlock(&sbi->lookup_lock);
153 dput(prev);
154 return NULL;
155 }
156
157 parent = p->d_parent;
158 if (!spin_trylock(&parent->d_lock)) {
159 spin_unlock(&p->d_lock);
160 cpu_relax();
161 goto relock;
162 }
163 spin_unlock(&p->d_lock);
164 next = p->d_u.d_child.next;
165 p = parent;
166 if (next != &parent->d_subdirs)
167 break;
168 }
169 }
170 ret = list_entry(next, struct dentry, d_u.d_child);
171
172 spin_lock_nested(&ret->d_lock, DENTRY_D_LOCK_NESTED);
173
174 if (!simple_positive(ret)) {
175 spin_unlock(&p->d_lock);
176 lock_set_subclass(&ret->d_lock.dep_map, 0, _RET_IP_);
177 p = ret;
178 goto again;
179 }
180 dget_dlock(ret);
181 spin_unlock(&ret->d_lock);
182 spin_unlock(&p->d_lock);
183 spin_unlock(&sbi->lookup_lock);
184
185 dput(prev);
186
187 return ret;
188}
189
190
191
192
193
194
195
196static int autofs4_direct_busy(struct vfsmount *mnt,
197 struct dentry *top,
198 unsigned long timeout,
199 int do_now)
200{
201 DPRINTK("top %p %.*s",
202 top, (int) top->d_name.len, top->d_name.name);
203
204
205 if (!may_umount_tree(mnt)) {
206 struct autofs_info *ino = autofs4_dentry_ino(top);
207 if (ino)
208 ino->last_used = jiffies;
209 return 1;
210 }
211
212
213 if (!autofs4_can_expire(top, timeout, do_now))
214 return 1;
215
216 return 0;
217}
218
219
220
221
222static int autofs4_tree_busy(struct vfsmount *mnt,
223 struct dentry *top,
224 unsigned long timeout,
225 int do_now)
226{
227 struct autofs_info *top_ino = autofs4_dentry_ino(top);
228 struct dentry *p;
229
230 DPRINTK("top %p %.*s",
231 top, (int)top->d_name.len, top->d_name.name);
232
233
234 if (!simple_positive(top))
235 return 1;
236
237 p = NULL;
238 while ((p = get_next_positive_dentry(p, top))) {
239 DPRINTK("dentry %p %.*s",
240 p, (int) p->d_name.len, p->d_name.name);
241
242
243
244
245
246
247
248 if (d_mountpoint(p)) {
249 if (autofs4_mount_busy(mnt, p)) {
250 top_ino->last_used = jiffies;
251 dput(p);
252 return 1;
253 }
254 } else {
255 struct autofs_info *ino = autofs4_dentry_ino(p);
256 unsigned int ino_count = atomic_read(&ino->count);
257
258
259
260
261
262 d_invalidate(p);
263
264
265 if (p == top)
266 ino_count += 2;
267 else
268 ino_count++;
269
270 if (d_count(p) > ino_count) {
271 top_ino->last_used = jiffies;
272 dput(p);
273 return 1;
274 }
275 }
276 }
277
278
279 if (!autofs4_can_expire(top, timeout, do_now))
280 return 1;
281
282 return 0;
283}
284
285static struct dentry *autofs4_check_leaves(struct vfsmount *mnt,
286 struct dentry *parent,
287 unsigned long timeout,
288 int do_now)
289{
290 struct dentry *p;
291
292 DPRINTK("parent %p %.*s",
293 parent, (int)parent->d_name.len, parent->d_name.name);
294
295 p = NULL;
296 while ((p = get_next_positive_dentry(p, parent))) {
297 DPRINTK("dentry %p %.*s",
298 p, (int) p->d_name.len, p->d_name.name);
299
300 if (d_mountpoint(p)) {
301
302 if (autofs4_mount_busy(mnt, p))
303 continue;
304
305
306 if (autofs4_can_expire(p, timeout, do_now))
307 return p;
308 }
309 }
310 return NULL;
311}
312
313
314struct dentry *autofs4_expire_direct(struct super_block *sb,
315 struct vfsmount *mnt,
316 struct autofs_sb_info *sbi,
317 int how)
318{
319 unsigned long timeout;
320 struct dentry *root = dget(sb->s_root);
321 int do_now = how & AUTOFS_EXP_IMMEDIATE;
322 struct autofs_info *ino;
323
324 if (!root)
325 return NULL;
326
327 now = jiffies;
328 timeout = sbi->exp_timeout;
329
330 spin_lock(&sbi->fs_lock);
331 ino = autofs4_dentry_ino(root);
332
333 if (ino->flags & AUTOFS_INF_PENDING)
334 goto out;
335 if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
336 struct autofs_info *ino = autofs4_dentry_ino(root);
337 ino->flags |= AUTOFS_INF_EXPIRING;
338 init_completion(&ino->expire_complete);
339 spin_unlock(&sbi->fs_lock);
340 return root;
341 }
342out:
343 spin_unlock(&sbi->fs_lock);
344 dput(root);
345
346 return NULL;
347}
348
349
350
351
352
353
354
355struct dentry *autofs4_expire_indirect(struct super_block *sb,
356 struct vfsmount *mnt,
357 struct autofs_sb_info *sbi,
358 int how)
359{
360 unsigned long timeout;
361 struct dentry *root = sb->s_root;
362 struct dentry *dentry;
363 struct dentry *expired = NULL;
364 int do_now = how & AUTOFS_EXP_IMMEDIATE;
365 int exp_leaves = how & AUTOFS_EXP_LEAVES;
366 struct autofs_info *ino;
367 unsigned int ino_count;
368
369 if (!root)
370 return NULL;
371
372 now = jiffies;
373 timeout = sbi->exp_timeout;
374
375 dentry = NULL;
376 while ((dentry = get_next_positive_subdir(dentry, root))) {
377 spin_lock(&sbi->fs_lock);
378 ino = autofs4_dentry_ino(dentry);
379
380 if (ino->flags & AUTOFS_INF_PENDING)
381 goto next;
382
383
384
385
386
387
388
389 if (d_mountpoint(dentry)) {
390 DPRINTK("checking mountpoint %p %.*s",
391 dentry, (int)dentry->d_name.len, dentry->d_name.name);
392
393
394 if (autofs4_mount_busy(mnt, dentry))
395 goto next;
396
397
398 if (autofs4_can_expire(dentry, timeout, do_now)) {
399 expired = dentry;
400 goto found;
401 }
402 goto next;
403 }
404
405 if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) {
406 DPRINTK("checking symlink %p %.*s",
407 dentry, (int)dentry->d_name.len, dentry->d_name.name);
408
409
410
411
412 if (autofs4_can_expire(dentry, timeout, do_now)) {
413 expired = dentry;
414 goto found;
415 }
416 goto next;
417 }
418
419 if (simple_empty(dentry))
420 goto next;
421
422
423 if (!exp_leaves) {
424
425 ino_count = atomic_read(&ino->count) + 1;
426 if (d_count(dentry) > ino_count)
427 goto next;
428
429 if (!autofs4_tree_busy(mnt, dentry, timeout, do_now)) {
430 expired = dentry;
431 goto found;
432 }
433
434
435
436
437 } else {
438
439 ino_count = atomic_read(&ino->count) + 1;
440 if (d_count(dentry) > ino_count)
441 goto next;
442
443 expired = autofs4_check_leaves(mnt, dentry, timeout, do_now);
444 if (expired) {
445 dput(dentry);
446 goto found;
447 }
448 }
449next:
450 spin_unlock(&sbi->fs_lock);
451 }
452 return NULL;
453
454found:
455 DPRINTK("returning %p %.*s",
456 expired, (int)expired->d_name.len, expired->d_name.name);
457 ino = autofs4_dentry_ino(expired);
458 ino->flags |= AUTOFS_INF_EXPIRING;
459 init_completion(&ino->expire_complete);
460 spin_unlock(&sbi->fs_lock);
461 spin_lock(&sbi->lookup_lock);
462 spin_lock(&expired->d_parent->d_lock);
463 spin_lock_nested(&expired->d_lock, DENTRY_D_LOCK_NESTED);
464 list_move(&expired->d_parent->d_subdirs, &expired->d_u.d_child);
465 spin_unlock(&expired->d_lock);
466 spin_unlock(&expired->d_parent->d_lock);
467 spin_unlock(&sbi->lookup_lock);
468 return expired;
469}
470
471int autofs4_expire_wait(struct dentry *dentry)
472{
473 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
474 struct autofs_info *ino = autofs4_dentry_ino(dentry);
475 int status;
476
477
478 spin_lock(&sbi->fs_lock);
479 if (ino->flags & AUTOFS_INF_EXPIRING) {
480 spin_unlock(&sbi->fs_lock);
481
482 DPRINTK("waiting for expire %p name=%.*s",
483 dentry, dentry->d_name.len, dentry->d_name.name);
484
485 status = autofs4_wait(sbi, dentry, NFY_NONE);
486 wait_for_completion(&ino->expire_complete);
487
488 DPRINTK("expire done status=%d", status);
489
490 if (d_unhashed(dentry))
491 return -EAGAIN;
492
493 return status;
494 }
495 spin_unlock(&sbi->fs_lock);
496
497 return 0;
498}
499
500
501int autofs4_expire_run(struct super_block *sb,
502 struct vfsmount *mnt,
503 struct autofs_sb_info *sbi,
504 struct autofs_packet_expire __user *pkt_p)
505{
506 struct autofs_packet_expire pkt;
507 struct autofs_info *ino;
508 struct dentry *dentry;
509 int ret = 0;
510
511 memset(&pkt,0,sizeof pkt);
512
513 pkt.hdr.proto_version = sbi->version;
514 pkt.hdr.type = autofs_ptype_expire;
515
516 if ((dentry = autofs4_expire_indirect(sb, mnt, sbi, 0)) == NULL)
517 return -EAGAIN;
518
519 pkt.len = dentry->d_name.len;
520 memcpy(pkt.name, dentry->d_name.name, pkt.len);
521 pkt.name[pkt.len] = '\0';
522 dput(dentry);
523
524 if ( copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)) )
525 ret = -EFAULT;
526
527 spin_lock(&sbi->fs_lock);
528 ino = autofs4_dentry_ino(dentry);
529 ino->flags &= ~AUTOFS_INF_EXPIRING;
530 complete_all(&ino->expire_complete);
531 spin_unlock(&sbi->fs_lock);
532
533 return ret;
534}
535
536int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
537 struct autofs_sb_info *sbi, int when)
538{
539 struct dentry *dentry;
540 int ret = -EAGAIN;
541
542 if (autofs_type_trigger(sbi->type))
543 dentry = autofs4_expire_direct(sb, mnt, sbi, when);
544 else
545 dentry = autofs4_expire_indirect(sb, mnt, sbi, when);
546
547 if (dentry) {
548 struct autofs_info *ino = autofs4_dentry_ino(dentry);
549
550
551
552 ret = autofs4_wait(sbi, dentry, NFY_EXPIRE);
553
554 spin_lock(&sbi->fs_lock);
555 ino->flags &= ~AUTOFS_INF_EXPIRING;
556 complete_all(&ino->expire_complete);
557 spin_unlock(&sbi->fs_lock);
558 dput(dentry);
559 }
560
561 return ret;
562}
563
564
565
566int autofs4_expire_multi(struct super_block *sb, struct vfsmount *mnt,
567 struct autofs_sb_info *sbi, int __user *arg)
568{
569 int do_now = 0;
570
571 if (arg && get_user(do_now, arg))
572 return -EFAULT;
573
574 return autofs4_do_expire_multi(sb, mnt, sbi, do_now);
575}
576
577