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1da177e4 LT |
1 | /* -*- c -*- --------------------------------------------------------------- * |
2 | * | |
3 | * linux/fs/autofs/waitq.c | |
4 | * | |
5 | * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved | |
5c0a32fc | 6 | * Copyright 2001-2006 Ian Kent <raven@themaw.net> |
1da177e4 LT |
7 | * |
8 | * This file is part of the Linux kernel and is made available under | |
9 | * the terms of the GNU General Public License, version 2, or at your | |
10 | * option, any later version, incorporated herein by reference. | |
11 | * | |
12 | * ------------------------------------------------------------------------- */ | |
13 | ||
14 | #include <linux/slab.h> | |
15 | #include <linux/time.h> | |
16 | #include <linux/signal.h> | |
17 | #include <linux/file.h> | |
18 | #include "autofs_i.h" | |
19 | ||
20 | /* We make this a static variable rather than a part of the superblock; it | |
21 | is better if we don't reassign numbers easily even across filesystems */ | |
22 | static autofs_wqt_t autofs4_next_wait_queue = 1; | |
23 | ||
24 | /* These are the signals we allow interrupting a pending mount */ | |
25 | #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT)) | |
26 | ||
27 | void autofs4_catatonic_mode(struct autofs_sb_info *sbi) | |
28 | { | |
29 | struct autofs_wait_queue *wq, *nwq; | |
30 | ||
31 | DPRINTK("entering catatonic mode"); | |
32 | ||
33 | sbi->catatonic = 1; | |
34 | wq = sbi->queues; | |
35 | sbi->queues = NULL; /* Erase all wait queues */ | |
e77fbddf | 36 | while (wq) { |
1da177e4 LT |
37 | nwq = wq->next; |
38 | wq->status = -ENOENT; /* Magic is gone - report failure */ | |
39 | kfree(wq->name); | |
40 | wq->name = NULL; | |
41 | wake_up_interruptible(&wq->queue); | |
42 | wq = nwq; | |
43 | } | |
44 | if (sbi->pipe) { | |
45 | fput(sbi->pipe); /* Close the pipe */ | |
46 | sbi->pipe = NULL; | |
47 | } | |
1da177e4 LT |
48 | } |
49 | ||
50 | static int autofs4_write(struct file *file, const void *addr, int bytes) | |
51 | { | |
52 | unsigned long sigpipe, flags; | |
53 | mm_segment_t fs; | |
54 | const char *data = (const char *)addr; | |
55 | ssize_t wr = 0; | |
56 | ||
57 | /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/ | |
58 | ||
59 | sigpipe = sigismember(¤t->pending.signal, SIGPIPE); | |
60 | ||
61 | /* Save pointer to user space and point back to kernel space */ | |
62 | fs = get_fs(); | |
63 | set_fs(KERNEL_DS); | |
64 | ||
65 | while (bytes && | |
66 | (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) { | |
67 | data += wr; | |
68 | bytes -= wr; | |
69 | } | |
70 | ||
71 | set_fs(fs); | |
72 | ||
73 | /* Keep the currently executing process from receiving a | |
74 | SIGPIPE unless it was already supposed to get one */ | |
75 | if (wr == -EPIPE && !sigpipe) { | |
76 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
77 | sigdelset(¤t->pending.signal, SIGPIPE); | |
78 | recalc_sigpending(); | |
79 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
80 | } | |
81 | ||
82 | return (bytes > 0); | |
83 | } | |
84 | ||
85 | static void autofs4_notify_daemon(struct autofs_sb_info *sbi, | |
86 | struct autofs_wait_queue *wq, | |
87 | int type) | |
88 | { | |
89 | union autofs_packet_union pkt; | |
90 | size_t pktsz; | |
91 | ||
92 | DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d", | |
93 | wq->wait_queue_token, wq->len, wq->name, type); | |
94 | ||
95 | memset(&pkt,0,sizeof pkt); /* For security reasons */ | |
96 | ||
97 | pkt.hdr.proto_version = sbi->version; | |
98 | pkt.hdr.type = type; | |
5c0a32fc IK |
99 | switch (type) { |
100 | /* Kernel protocol v4 missing and expire packets */ | |
101 | case autofs_ptype_missing: | |
102 | { | |
1da177e4 LT |
103 | struct autofs_packet_missing *mp = &pkt.missing; |
104 | ||
105 | pktsz = sizeof(*mp); | |
106 | ||
107 | mp->wait_queue_token = wq->wait_queue_token; | |
108 | mp->len = wq->len; | |
109 | memcpy(mp->name, wq->name, wq->len); | |
110 | mp->name[wq->len] = '\0'; | |
5c0a32fc IK |
111 | break; |
112 | } | |
113 | case autofs_ptype_expire_multi: | |
114 | { | |
1da177e4 LT |
115 | struct autofs_packet_expire_multi *ep = &pkt.expire_multi; |
116 | ||
117 | pktsz = sizeof(*ep); | |
118 | ||
119 | ep->wait_queue_token = wq->wait_queue_token; | |
120 | ep->len = wq->len; | |
121 | memcpy(ep->name, wq->name, wq->len); | |
122 | ep->name[wq->len] = '\0'; | |
5c0a32fc IK |
123 | break; |
124 | } | |
125 | /* | |
126 | * Kernel protocol v5 packet for handling indirect and direct | |
127 | * mount missing and expire requests | |
128 | */ | |
129 | case autofs_ptype_missing_indirect: | |
130 | case autofs_ptype_expire_indirect: | |
131 | case autofs_ptype_missing_direct: | |
132 | case autofs_ptype_expire_direct: | |
133 | { | |
134 | struct autofs_v5_packet *packet = &pkt.v5_packet; | |
135 | ||
136 | pktsz = sizeof(*packet); | |
137 | ||
138 | packet->wait_queue_token = wq->wait_queue_token; | |
139 | packet->len = wq->len; | |
140 | memcpy(packet->name, wq->name, wq->len); | |
141 | packet->name[wq->len] = '\0'; | |
142 | packet->dev = wq->dev; | |
143 | packet->ino = wq->ino; | |
144 | packet->uid = wq->uid; | |
145 | packet->gid = wq->gid; | |
146 | packet->pid = wq->pid; | |
147 | packet->tgid = wq->tgid; | |
148 | break; | |
149 | } | |
150 | default: | |
1da177e4 LT |
151 | printk("autofs4_notify_daemon: bad type %d!\n", type); |
152 | return; | |
153 | } | |
154 | ||
155 | if (autofs4_write(sbi->pipe, &pkt, pktsz)) | |
156 | autofs4_catatonic_mode(sbi); | |
157 | } | |
158 | ||
159 | static int autofs4_getpath(struct autofs_sb_info *sbi, | |
160 | struct dentry *dentry, char **name) | |
161 | { | |
162 | struct dentry *root = sbi->sb->s_root; | |
163 | struct dentry *tmp; | |
164 | char *buf = *name; | |
165 | char *p; | |
166 | int len = 0; | |
167 | ||
168 | spin_lock(&dcache_lock); | |
169 | for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent) | |
170 | len += tmp->d_name.len + 1; | |
171 | ||
172 | if (--len > NAME_MAX) { | |
173 | spin_unlock(&dcache_lock); | |
174 | return 0; | |
175 | } | |
176 | ||
177 | *(buf + len) = '\0'; | |
178 | p = buf + len - dentry->d_name.len; | |
179 | strncpy(p, dentry->d_name.name, dentry->d_name.len); | |
180 | ||
181 | for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) { | |
182 | *(--p) = '/'; | |
183 | p -= tmp->d_name.len; | |
184 | strncpy(p, tmp->d_name.name, tmp->d_name.len); | |
185 | } | |
186 | spin_unlock(&dcache_lock); | |
187 | ||
188 | return len; | |
189 | } | |
190 | ||
a5370553 IK |
191 | static struct autofs_wait_queue * |
192 | autofs4_find_wait(struct autofs_sb_info *sbi, | |
193 | char *name, unsigned int hash, unsigned int len) | |
194 | { | |
195 | struct autofs_wait_queue *wq; | |
196 | ||
197 | for (wq = sbi->queues; wq; wq = wq->next) { | |
198 | if (wq->hash == hash && | |
199 | wq->len == len && | |
200 | wq->name && !memcmp(wq->name, name, len)) | |
201 | break; | |
202 | } | |
203 | return wq; | |
204 | } | |
205 | ||
1da177e4 LT |
206 | int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry, |
207 | enum autofs_notify notify) | |
208 | { | |
a5370553 | 209 | struct autofs_info *ino; |
1da177e4 LT |
210 | struct autofs_wait_queue *wq; |
211 | char *name; | |
5c0a32fc IK |
212 | unsigned int len = 0; |
213 | unsigned int hash = 0; | |
a5370553 | 214 | int status, type; |
1da177e4 LT |
215 | |
216 | /* In catatonic mode, we don't wait for nobody */ | |
e77fbddf | 217 | if (sbi->catatonic) |
1da177e4 LT |
218 | return -ENOENT; |
219 | ||
220 | name = kmalloc(NAME_MAX + 1, GFP_KERNEL); | |
221 | if (!name) | |
222 | return -ENOMEM; | |
223 | ||
5c0a32fc | 224 | /* If this is a direct mount request create a dummy name */ |
44d53eb0 | 225 | if (IS_ROOT(dentry) && (sbi->type & AUTOFS_TYPE_DIRECT)) |
5c0a32fc IK |
226 | len = sprintf(name, "%p", dentry); |
227 | else { | |
228 | len = autofs4_getpath(sbi, dentry, &name); | |
229 | if (!len) { | |
230 | kfree(name); | |
231 | return -ENOENT; | |
232 | } | |
1da177e4 | 233 | } |
5c0a32fc | 234 | hash = full_name_hash(name, len); |
1da177e4 | 235 | |
1d5599e3 | 236 | if (mutex_lock_interruptible(&sbi->wq_mutex)) { |
1da177e4 LT |
237 | kfree(name); |
238 | return -EINTR; | |
239 | } | |
240 | ||
a5370553 IK |
241 | wq = autofs4_find_wait(sbi, name, hash, len); |
242 | ino = autofs4_dentry_ino(dentry); | |
243 | if (!wq && ino && notify == NFY_NONE) { | |
244 | /* | |
245 | * Either we've betean the pending expire to post it's | |
246 | * wait or it finished while we waited on the mutex. | |
247 | * So we need to wait till either, the wait appears | |
248 | * or the expire finishes. | |
249 | */ | |
250 | ||
251 | while (ino->flags & AUTOFS_INF_EXPIRING) { | |
252 | mutex_unlock(&sbi->wq_mutex); | |
253 | schedule_timeout_interruptible(HZ/10); | |
254 | if (mutex_lock_interruptible(&sbi->wq_mutex)) { | |
255 | kfree(name); | |
256 | return -EINTR; | |
257 | } | |
258 | wq = autofs4_find_wait(sbi, name, hash, len); | |
259 | if (wq) | |
260 | break; | |
261 | } | |
1da177e4 | 262 | |
a5370553 IK |
263 | /* |
264 | * Not ideal but the status has already gone. Of the two | |
265 | * cases where we wait on NFY_NONE neither depend on the | |
266 | * return status of the wait. | |
267 | */ | |
268 | if (!wq) { | |
cc9acc88 | 269 | kfree(name); |
1d5599e3 | 270 | mutex_unlock(&sbi->wq_mutex); |
a5370553 | 271 | return 0; |
cc9acc88 | 272 | } |
a5370553 | 273 | } |
cc9acc88 | 274 | |
a5370553 | 275 | if (!wq) { |
1da177e4 LT |
276 | /* Create a new wait queue */ |
277 | wq = kmalloc(sizeof(struct autofs_wait_queue),GFP_KERNEL); | |
e77fbddf | 278 | if (!wq) { |
1da177e4 | 279 | kfree(name); |
1d5599e3 | 280 | mutex_unlock(&sbi->wq_mutex); |
1da177e4 LT |
281 | return -ENOMEM; |
282 | } | |
283 | ||
284 | wq->wait_queue_token = autofs4_next_wait_queue; | |
285 | if (++autofs4_next_wait_queue == 0) | |
286 | autofs4_next_wait_queue = 1; | |
287 | wq->next = sbi->queues; | |
288 | sbi->queues = wq; | |
289 | init_waitqueue_head(&wq->queue); | |
5c0a32fc | 290 | wq->hash = hash; |
1da177e4 LT |
291 | wq->name = name; |
292 | wq->len = len; | |
5c0a32fc IK |
293 | wq->dev = autofs4_get_dev(sbi); |
294 | wq->ino = autofs4_get_ino(sbi); | |
295 | wq->uid = current->uid; | |
296 | wq->gid = current->gid; | |
297 | wq->pid = current->pid; | |
298 | wq->tgid = current->tgid; | |
1da177e4 LT |
299 | wq->status = -EINTR; /* Status return if interrupted */ |
300 | atomic_set(&wq->wait_ctr, 2); | |
1d5599e3 | 301 | mutex_unlock(&sbi->wq_mutex); |
3e7b1919 | 302 | |
5c0a32fc IK |
303 | if (sbi->version < 5) { |
304 | if (notify == NFY_MOUNT) | |
305 | type = autofs_ptype_missing; | |
306 | else | |
307 | type = autofs_ptype_expire_multi; | |
308 | } else { | |
309 | if (notify == NFY_MOUNT) | |
44d53eb0 | 310 | type = (sbi->type & AUTOFS_TYPE_DIRECT) ? |
5c0a32fc IK |
311 | autofs_ptype_missing_direct : |
312 | autofs_ptype_missing_indirect; | |
313 | else | |
44d53eb0 | 314 | type = (sbi->type & AUTOFS_TYPE_DIRECT) ? |
5c0a32fc IK |
315 | autofs_ptype_expire_direct : |
316 | autofs_ptype_expire_indirect; | |
317 | } | |
4dcd00b1 | 318 | |
682d4fc9 IK |
319 | DPRINTK("new wait id = 0x%08lx, name = %.*s, nfy=%d\n", |
320 | (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify); | |
4dcd00b1 IK |
321 | |
322 | /* autofs4_notify_daemon() may block */ | |
323 | autofs4_notify_daemon(sbi, wq, type); | |
a5370553 IK |
324 | } else { |
325 | atomic_inc(&wq->wait_ctr); | |
326 | mutex_unlock(&sbi->wq_mutex); | |
327 | kfree(name); | |
328 | DPRINTK("existing wait id = 0x%08lx, name = %.*s, nfy=%d", | |
329 | (unsigned long) wq->wait_queue_token, wq->len, wq->name, notify); | |
4dcd00b1 IK |
330 | } |
331 | ||
1da177e4 LT |
332 | /* wq->name is NULL if and only if the lock is already released */ |
333 | ||
e77fbddf | 334 | if (sbi->catatonic) { |
1da177e4 LT |
335 | /* We might have slept, so check again for catatonic mode */ |
336 | wq->status = -ENOENT; | |
f99d49ad JJ |
337 | kfree(wq->name); |
338 | wq->name = NULL; | |
1da177e4 LT |
339 | } |
340 | ||
e77fbddf | 341 | if (wq->name) { |
1da177e4 LT |
342 | /* Block all but "shutdown" signals while waiting */ |
343 | sigset_t oldset; | |
344 | unsigned long irqflags; | |
345 | ||
346 | spin_lock_irqsave(¤t->sighand->siglock, irqflags); | |
347 | oldset = current->blocked; | |
348 | siginitsetinv(¤t->blocked, SHUTDOWN_SIGS & ~oldset.sig[0]); | |
349 | recalc_sigpending(); | |
350 | spin_unlock_irqrestore(¤t->sighand->siglock, irqflags); | |
351 | ||
352 | wait_event_interruptible(wq->queue, wq->name == NULL); | |
353 | ||
354 | spin_lock_irqsave(¤t->sighand->siglock, irqflags); | |
355 | current->blocked = oldset; | |
356 | recalc_sigpending(); | |
357 | spin_unlock_irqrestore(¤t->sighand->siglock, irqflags); | |
358 | } else { | |
359 | DPRINTK("skipped sleeping"); | |
360 | } | |
361 | ||
362 | status = wq->status; | |
363 | ||
364 | /* Are we the last process to need status? */ | |
365 | if (atomic_dec_and_test(&wq->wait_ctr)) | |
366 | kfree(wq); | |
367 | ||
368 | return status; | |
369 | } | |
370 | ||
371 | ||
372 | int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status) | |
373 | { | |
374 | struct autofs_wait_queue *wq, **wql; | |
375 | ||
1d5599e3 | 376 | mutex_lock(&sbi->wq_mutex); |
e77fbddf IK |
377 | for (wql = &sbi->queues ; (wq = *wql) != 0 ; wql = &wq->next) { |
378 | if (wq->wait_queue_token == wait_queue_token) | |
1da177e4 LT |
379 | break; |
380 | } | |
381 | ||
e77fbddf | 382 | if (!wq) { |
1d5599e3 | 383 | mutex_unlock(&sbi->wq_mutex); |
1da177e4 LT |
384 | return -EINVAL; |
385 | } | |
386 | ||
387 | *wql = wq->next; /* Unlink from chain */ | |
1d5599e3 | 388 | mutex_unlock(&sbi->wq_mutex); |
1da177e4 LT |
389 | kfree(wq->name); |
390 | wq->name = NULL; /* Do not wait on this queue */ | |
391 | ||
392 | wq->status = status; | |
393 | ||
394 | if (atomic_dec_and_test(&wq->wait_ctr)) /* Is anyone still waiting for this guy? */ | |
395 | kfree(wq); | |
396 | else | |
397 | wake_up_interruptible(&wq->queue); | |
398 | ||
399 | return 0; | |
400 | } | |
401 |