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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/miscdevice.h>
8#include <linux/poll.h>
9#include <linux/dlm.h>
10#include <linux/dlm_plock.h>
11#include <linux/slab.h>
12
13#include "dlm_internal.h"
14#include "lockspace.h"
15
16static spinlock_t ops_lock;
17static struct list_head send_list;
18static struct list_head recv_list;
19static wait_queue_head_t send_wq;
20static wait_queue_head_t recv_wq;
21
22struct plock_op {
23 struct list_head list;
24 int done;
25 struct dlm_plock_info info;
26};
27
28struct plock_xop {
29 struct plock_op xop;
30 int (*callback)(struct file_lock *fl, int result);
31 void *fl;
32 void *file;
33 struct file_lock flc;
34};
35
36
37static inline void set_version(struct dlm_plock_info *info)
38{
39 info->version[0] = DLM_PLOCK_VERSION_MAJOR;
40 info->version[1] = DLM_PLOCK_VERSION_MINOR;
41 info->version[2] = DLM_PLOCK_VERSION_PATCH;
42}
43
44static int check_version(struct dlm_plock_info *info)
45{
46 if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
47 (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
48 log_print("plock device version mismatch: "
49 "kernel (%u.%u.%u), user (%u.%u.%u)",
50 DLM_PLOCK_VERSION_MAJOR,
51 DLM_PLOCK_VERSION_MINOR,
52 DLM_PLOCK_VERSION_PATCH,
53 info->version[0],
54 info->version[1],
55 info->version[2]);
56 return -EINVAL;
57 }
58 return 0;
59}
60
61static void send_op(struct plock_op *op)
62{
63 set_version(&op->info);
64 INIT_LIST_HEAD(&op->list);
65 spin_lock(&ops_lock);
66 list_add_tail(&op->list, &send_list);
67 spin_unlock(&ops_lock);
68 wake_up(&send_wq);
69}
70
71/* If a process was killed while waiting for the only plock on a file,
72 locks_remove_posix will not see any lock on the file so it won't
73 send an unlock-close to us to pass on to userspace to clean up the
74 abandoned waiter. So, we have to insert the unlock-close when the
75 lock call is interrupted. */
76
77static void do_unlock_close(struct dlm_ls *ls, u64 number,
78 struct file *file, struct file_lock *fl)
79{
80 struct plock_op *op;
81
82 op = kzalloc(sizeof(*op), GFP_NOFS);
83 if (!op)
84 return;
85
86 op->info.optype = DLM_PLOCK_OP_UNLOCK;
87 op->info.pid = fl->fl_pid;
88 op->info.fsid = ls->ls_global_id;
89 op->info.number = number;
90 op->info.start = 0;
91 op->info.end = OFFSET_MAX;
92 if (fl->fl_lmops && fl->fl_lmops->lm_grant)
93 op->info.owner = (__u64) fl->fl_pid;
94 else
95 op->info.owner = (__u64)(long) fl->fl_owner;
96
97 op->info.flags |= DLM_PLOCK_FL_CLOSE;
98 send_op(op);
99}
100
101int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
102 int cmd, struct file_lock *fl)
103{
104 struct dlm_ls *ls;
105 struct plock_op *op;
106 struct plock_xop *xop;
107 int rv;
108
109 ls = dlm_find_lockspace_local(lockspace);
110 if (!ls)
111 return -EINVAL;
112
113 xop = kzalloc(sizeof(*xop), GFP_NOFS);
114 if (!xop) {
115 rv = -ENOMEM;
116 goto out;
117 }
118
119 op = &xop->xop;
120 op->info.optype = DLM_PLOCK_OP_LOCK;
121 op->info.pid = fl->fl_pid;
122 op->info.ex = (fl->fl_type == F_WRLCK);
123 op->info.wait = IS_SETLKW(cmd);
124 op->info.fsid = ls->ls_global_id;
125 op->info.number = number;
126 op->info.start = fl->fl_start;
127 op->info.end = fl->fl_end;
128 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
129 /* fl_owner is lockd which doesn't distinguish
130 processes on the nfs client */
131 op->info.owner = (__u64) fl->fl_pid;
132 xop->callback = fl->fl_lmops->lm_grant;
133 locks_init_lock(&xop->flc);
134 locks_copy_lock(&xop->flc, fl);
135 xop->fl = fl;
136 xop->file = file;
137 } else {
138 op->info.owner = (__u64)(long) fl->fl_owner;
139 xop->callback = NULL;
140 }
141
142 send_op(op);
143
144 if (xop->callback == NULL) {
145 rv = wait_event_interruptible(recv_wq, (op->done != 0));
146 if (rv == -ERESTARTSYS) {
147 log_debug(ls, "dlm_posix_lock: wait killed %llx",
148 (unsigned long long)number);
149 spin_lock(&ops_lock);
150 list_del(&op->list);
151 spin_unlock(&ops_lock);
152 kfree(xop);
153 do_unlock_close(ls, number, file, fl);
154 goto out;
155 }
156 } else {
157 rv = FILE_LOCK_DEFERRED;
158 goto out;
159 }
160
161 spin_lock(&ops_lock);
162 if (!list_empty(&op->list)) {
163 log_error(ls, "dlm_posix_lock: op on list %llx",
164 (unsigned long long)number);
165 list_del(&op->list);
166 }
167 spin_unlock(&ops_lock);
168
169 rv = op->info.rv;
170
171 if (!rv) {
172 if (locks_lock_file_wait(file, fl) < 0)
173 log_error(ls, "dlm_posix_lock: vfs lock error %llx",
174 (unsigned long long)number);
175 }
176
177 kfree(xop);
178out:
179 dlm_put_lockspace(ls);
180 return rv;
181}
182EXPORT_SYMBOL_GPL(dlm_posix_lock);
183
184/* Returns failure iff a successful lock operation should be canceled */
185static int dlm_plock_callback(struct plock_op *op)
186{
187 struct file *file;
188 struct file_lock *fl;
189 struct file_lock *flc;
190 int (*notify)(struct file_lock *fl, int result) = NULL;
191 struct plock_xop *xop = (struct plock_xop *)op;
192 int rv = 0;
193
194 spin_lock(&ops_lock);
195 if (!list_empty(&op->list)) {
196 log_print("dlm_plock_callback: op on list %llx",
197 (unsigned long long)op->info.number);
198 list_del(&op->list);
199 }
200 spin_unlock(&ops_lock);
201
202 /* check if the following 2 are still valid or make a copy */
203 file = xop->file;
204 flc = &xop->flc;
205 fl = xop->fl;
206 notify = xop->callback;
207
208 if (op->info.rv) {
209 notify(fl, op->info.rv);
210 goto out;
211 }
212
213 /* got fs lock; bookkeep locally as well: */
214 flc->fl_flags &= ~FL_SLEEP;
215 if (posix_lock_file(file, flc, NULL)) {
216 /*
217 * This can only happen in the case of kmalloc() failure.
218 * The filesystem's own lock is the authoritative lock,
219 * so a failure to get the lock locally is not a disaster.
220 * As long as the fs cannot reliably cancel locks (especially
221 * in a low-memory situation), we're better off ignoring
222 * this failure than trying to recover.
223 */
224 log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
225 (unsigned long long)op->info.number, file, fl);
226 }
227
228 rv = notify(fl, 0);
229 if (rv) {
230 /* XXX: We need to cancel the fs lock here: */
231 log_print("dlm_plock_callback: lock granted after lock request "
232 "failed; dangling lock!\n");
233 goto out;
234 }
235
236out:
237 kfree(xop);
238 return rv;
239}
240
241int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
242 struct file_lock *fl)
243{
244 struct dlm_ls *ls;
245 struct plock_op *op;
246 int rv;
247 unsigned char fl_flags = fl->fl_flags;
248
249 ls = dlm_find_lockspace_local(lockspace);
250 if (!ls)
251 return -EINVAL;
252
253 op = kzalloc(sizeof(*op), GFP_NOFS);
254 if (!op) {
255 rv = -ENOMEM;
256 goto out;
257 }
258
259 /* cause the vfs unlock to return ENOENT if lock is not found */
260 fl->fl_flags |= FL_EXISTS;
261
262 rv = locks_lock_file_wait(file, fl);
263 if (rv == -ENOENT) {
264 rv = 0;
265 goto out_free;
266 }
267 if (rv < 0) {
268 log_error(ls, "dlm_posix_unlock: vfs unlock error %d %llx",
269 rv, (unsigned long long)number);
270 }
271
272 op->info.optype = DLM_PLOCK_OP_UNLOCK;
273 op->info.pid = fl->fl_pid;
274 op->info.fsid = ls->ls_global_id;
275 op->info.number = number;
276 op->info.start = fl->fl_start;
277 op->info.end = fl->fl_end;
278 if (fl->fl_lmops && fl->fl_lmops->lm_grant)
279 op->info.owner = (__u64) fl->fl_pid;
280 else
281 op->info.owner = (__u64)(long) fl->fl_owner;
282
283 if (fl->fl_flags & FL_CLOSE) {
284 op->info.flags |= DLM_PLOCK_FL_CLOSE;
285 send_op(op);
286 rv = 0;
287 goto out;
288 }
289
290 send_op(op);
291 wait_event(recv_wq, (op->done != 0));
292
293 spin_lock(&ops_lock);
294 if (!list_empty(&op->list)) {
295 log_error(ls, "dlm_posix_unlock: op on list %llx",
296 (unsigned long long)number);
297 list_del(&op->list);
298 }
299 spin_unlock(&ops_lock);
300
301 rv = op->info.rv;
302
303 if (rv == -ENOENT)
304 rv = 0;
305
306out_free:
307 kfree(op);
308out:
309 dlm_put_lockspace(ls);
310 fl->fl_flags = fl_flags;
311 return rv;
312}
313EXPORT_SYMBOL_GPL(dlm_posix_unlock);
314
315int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
316 struct file_lock *fl)
317{
318 struct dlm_ls *ls;
319 struct plock_op *op;
320 int rv;
321
322 ls = dlm_find_lockspace_local(lockspace);
323 if (!ls)
324 return -EINVAL;
325
326 op = kzalloc(sizeof(*op), GFP_NOFS);
327 if (!op) {
328 rv = -ENOMEM;
329 goto out;
330 }
331
332 op->info.optype = DLM_PLOCK_OP_GET;
333 op->info.pid = fl->fl_pid;
334 op->info.ex = (fl->fl_type == F_WRLCK);
335 op->info.fsid = ls->ls_global_id;
336 op->info.number = number;
337 op->info.start = fl->fl_start;
338 op->info.end = fl->fl_end;
339 if (fl->fl_lmops && fl->fl_lmops->lm_grant)
340 op->info.owner = (__u64) fl->fl_pid;
341 else
342 op->info.owner = (__u64)(long) fl->fl_owner;
343
344 send_op(op);
345 wait_event(recv_wq, (op->done != 0));
346
347 spin_lock(&ops_lock);
348 if (!list_empty(&op->list)) {
349 log_error(ls, "dlm_posix_get: op on list %llx",
350 (unsigned long long)number);
351 list_del(&op->list);
352 }
353 spin_unlock(&ops_lock);
354
355 /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
356 -ENOENT if there are no locks on the file */
357
358 rv = op->info.rv;
359
360 fl->fl_type = F_UNLCK;
361 if (rv == -ENOENT)
362 rv = 0;
363 else if (rv > 0) {
364 locks_init_lock(fl);
365 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
366 fl->fl_flags = FL_POSIX;
367 fl->fl_pid = -op->info.pid;
368 fl->fl_start = op->info.start;
369 fl->fl_end = op->info.end;
370 rv = 0;
371 }
372
373 kfree(op);
374out:
375 dlm_put_lockspace(ls);
376 return rv;
377}
378EXPORT_SYMBOL_GPL(dlm_posix_get);
379
380/* a read copies out one plock request from the send list */
381static ssize_t dev_read(struct file *file, char __user *u, size_t count,
382 loff_t *ppos)
383{
384 struct dlm_plock_info info;
385 struct plock_op *op = NULL;
386
387 if (count < sizeof(info))
388 return -EINVAL;
389
390 spin_lock(&ops_lock);
391 if (!list_empty(&send_list)) {
392 op = list_entry(send_list.next, struct plock_op, list);
393 if (op->info.flags & DLM_PLOCK_FL_CLOSE)
394 list_del(&op->list);
395 else
396 list_move(&op->list, &recv_list);
397 memcpy(&info, &op->info, sizeof(info));
398 }
399 spin_unlock(&ops_lock);
400
401 if (!op)
402 return -EAGAIN;
403
404 /* there is no need to get a reply from userspace for unlocks
405 that were generated by the vfs cleaning up for a close
406 (the process did not make an unlock call). */
407
408 if (op->info.flags & DLM_PLOCK_FL_CLOSE)
409 kfree(op);
410
411 if (copy_to_user(u, &info, sizeof(info)))
412 return -EFAULT;
413 return sizeof(info);
414}
415
416/* a write copies in one plock result that should match a plock_op
417 on the recv list */
418static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
419 loff_t *ppos)
420{
421 struct dlm_plock_info info;
422 struct plock_op *op;
423 int found = 0, do_callback = 0;
424
425 if (count != sizeof(info))
426 return -EINVAL;
427
428 if (copy_from_user(&info, u, sizeof(info)))
429 return -EFAULT;
430
431 if (check_version(&info))
432 return -EINVAL;
433
434 spin_lock(&ops_lock);
435 list_for_each_entry(op, &recv_list, list) {
436 if (op->info.fsid == info.fsid &&
437 op->info.number == info.number &&
438 op->info.owner == info.owner) {
439 struct plock_xop *xop = (struct plock_xop *)op;
440 list_del_init(&op->list);
441 memcpy(&op->info, &info, sizeof(info));
442 if (xop->callback)
443 do_callback = 1;
444 else
445 op->done = 1;
446 found = 1;
447 break;
448 }
449 }
450 spin_unlock(&ops_lock);
451
452 if (found) {
453 if (do_callback)
454 dlm_plock_callback(op);
455 else
456 wake_up(&recv_wq);
457 } else
458 log_print("dev_write no op %x %llx", info.fsid,
459 (unsigned long long)info.number);
460 return count;
461}
462
463static __poll_t dev_poll(struct file *file, poll_table *wait)
464{
465 __poll_t mask = 0;
466
467 poll_wait(file, &send_wq, wait);
468
469 spin_lock(&ops_lock);
470 if (!list_empty(&send_list))
471 mask = EPOLLIN | EPOLLRDNORM;
472 spin_unlock(&ops_lock);
473
474 return mask;
475}
476
477static const struct file_operations dev_fops = {
478 .read = dev_read,
479 .write = dev_write,
480 .poll = dev_poll,
481 .owner = THIS_MODULE,
482 .llseek = noop_llseek,
483};
484
485static struct miscdevice plock_dev_misc = {
486 .minor = MISC_DYNAMIC_MINOR,
487 .name = DLM_PLOCK_MISC_NAME,
488 .fops = &dev_fops
489};
490
491int dlm_plock_init(void)
492{
493 int rv;
494
495 spin_lock_init(&ops_lock);
496 INIT_LIST_HEAD(&send_list);
497 INIT_LIST_HEAD(&recv_list);
498 init_waitqueue_head(&send_wq);
499 init_waitqueue_head(&recv_wq);
500
501 rv = misc_register(&plock_dev_misc);
502 if (rv)
503 log_print("dlm_plock_init: misc_register failed %d", rv);
504 return rv;
505}
506
507void dlm_plock_exit(void)
508{
509 misc_deregister(&plock_dev_misc);
510}
511
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/filelock.h>
8#include <linux/miscdevice.h>
9#include <linux/poll.h>
10#include <linux/dlm.h>
11#include <linux/dlm_plock.h>
12#include <linux/slab.h>
13
14#include <trace/events/dlm.h>
15
16#include "dlm_internal.h"
17#include "lockspace.h"
18
19static DEFINE_SPINLOCK(ops_lock);
20static LIST_HEAD(send_list);
21static LIST_HEAD(recv_list);
22static DECLARE_WAIT_QUEUE_HEAD(send_wq);
23static DECLARE_WAIT_QUEUE_HEAD(recv_wq);
24
25struct plock_async_data {
26 void *fl;
27 void *file;
28 struct file_lock flc;
29 int (*callback)(struct file_lock *fl, int result);
30};
31
32struct plock_op {
33 struct list_head list;
34 int done;
35 struct dlm_plock_info info;
36 /* if set indicates async handling */
37 struct plock_async_data *data;
38};
39
40static inline void set_version(struct dlm_plock_info *info)
41{
42 info->version[0] = DLM_PLOCK_VERSION_MAJOR;
43 info->version[1] = DLM_PLOCK_VERSION_MINOR;
44 info->version[2] = DLM_PLOCK_VERSION_PATCH;
45}
46
47static struct plock_op *plock_lookup_waiter(const struct dlm_plock_info *info)
48{
49 struct plock_op *op = NULL, *iter;
50
51 list_for_each_entry(iter, &recv_list, list) {
52 if (iter->info.fsid == info->fsid &&
53 iter->info.number == info->number &&
54 iter->info.owner == info->owner &&
55 iter->info.pid == info->pid &&
56 iter->info.start == info->start &&
57 iter->info.end == info->end &&
58 iter->info.ex == info->ex &&
59 iter->info.wait) {
60 op = iter;
61 break;
62 }
63 }
64
65 return op;
66}
67
68static int check_version(struct dlm_plock_info *info)
69{
70 if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
71 (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
72 log_print("plock device version mismatch: "
73 "kernel (%u.%u.%u), user (%u.%u.%u)",
74 DLM_PLOCK_VERSION_MAJOR,
75 DLM_PLOCK_VERSION_MINOR,
76 DLM_PLOCK_VERSION_PATCH,
77 info->version[0],
78 info->version[1],
79 info->version[2]);
80 return -EINVAL;
81 }
82 return 0;
83}
84
85static void dlm_release_plock_op(struct plock_op *op)
86{
87 kfree(op->data);
88 kfree(op);
89}
90
91static void send_op(struct plock_op *op)
92{
93 set_version(&op->info);
94 spin_lock(&ops_lock);
95 list_add_tail(&op->list, &send_list);
96 spin_unlock(&ops_lock);
97 wake_up(&send_wq);
98}
99
100static int do_lock_cancel(const struct dlm_plock_info *orig_info)
101{
102 struct plock_op *op;
103 int rv;
104
105 op = kzalloc(sizeof(*op), GFP_NOFS);
106 if (!op)
107 return -ENOMEM;
108
109 op->info = *orig_info;
110 op->info.optype = DLM_PLOCK_OP_CANCEL;
111 op->info.wait = 0;
112
113 send_op(op);
114 wait_event(recv_wq, (op->done != 0));
115
116 rv = op->info.rv;
117
118 dlm_release_plock_op(op);
119 return rv;
120}
121
122int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
123 int cmd, struct file_lock *fl)
124{
125 struct plock_async_data *op_data;
126 struct dlm_ls *ls;
127 struct plock_op *op;
128 int rv;
129
130 ls = dlm_find_lockspace_local(lockspace);
131 if (!ls)
132 return -EINVAL;
133
134 op = kzalloc(sizeof(*op), GFP_NOFS);
135 if (!op) {
136 rv = -ENOMEM;
137 goto out;
138 }
139
140 op->info.optype = DLM_PLOCK_OP_LOCK;
141 op->info.pid = fl->fl_pid;
142 op->info.ex = (fl->fl_type == F_WRLCK);
143 op->info.wait = !!(fl->fl_flags & FL_SLEEP);
144 op->info.fsid = ls->ls_global_id;
145 op->info.number = number;
146 op->info.start = fl->fl_start;
147 op->info.end = fl->fl_end;
148 op->info.owner = (__u64)(long)fl->fl_owner;
149 /* async handling */
150 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
151 op_data = kzalloc(sizeof(*op_data), GFP_NOFS);
152 if (!op_data) {
153 dlm_release_plock_op(op);
154 rv = -ENOMEM;
155 goto out;
156 }
157
158 op_data->callback = fl->fl_lmops->lm_grant;
159 locks_init_lock(&op_data->flc);
160 locks_copy_lock(&op_data->flc, fl);
161 op_data->fl = fl;
162 op_data->file = file;
163
164 op->data = op_data;
165
166 send_op(op);
167 rv = FILE_LOCK_DEFERRED;
168 goto out;
169 }
170
171 send_op(op);
172
173 if (op->info.wait) {
174 rv = wait_event_interruptible(recv_wq, (op->done != 0));
175 if (rv == -ERESTARTSYS) {
176 spin_lock(&ops_lock);
177 /* recheck under ops_lock if we got a done != 0,
178 * if so this interrupt case should be ignored
179 */
180 if (op->done != 0) {
181 spin_unlock(&ops_lock);
182 goto do_lock_wait;
183 }
184 spin_unlock(&ops_lock);
185
186 rv = do_lock_cancel(&op->info);
187 switch (rv) {
188 case 0:
189 /* waiter was deleted in user space, answer will never come
190 * remove original request. The original request must be
191 * on recv_list because the answer of do_lock_cancel()
192 * synchronized it.
193 */
194 spin_lock(&ops_lock);
195 list_del(&op->list);
196 spin_unlock(&ops_lock);
197 rv = -EINTR;
198 break;
199 case -ENOENT:
200 /* cancellation wasn't successful but op should be done */
201 fallthrough;
202 default:
203 /* internal error doing cancel we need to wait */
204 goto wait;
205 }
206
207 log_debug(ls, "%s: wait interrupted %x %llx pid %d",
208 __func__, ls->ls_global_id,
209 (unsigned long long)number, op->info.pid);
210 dlm_release_plock_op(op);
211 goto out;
212 }
213 } else {
214wait:
215 wait_event(recv_wq, (op->done != 0));
216 }
217
218do_lock_wait:
219
220 WARN_ON(!list_empty(&op->list));
221
222 rv = op->info.rv;
223
224 if (!rv) {
225 if (locks_lock_file_wait(file, fl) < 0)
226 log_error(ls, "dlm_posix_lock: vfs lock error %llx",
227 (unsigned long long)number);
228 }
229
230 dlm_release_plock_op(op);
231out:
232 dlm_put_lockspace(ls);
233 return rv;
234}
235EXPORT_SYMBOL_GPL(dlm_posix_lock);
236
237/* Returns failure iff a successful lock operation should be canceled */
238static int dlm_plock_callback(struct plock_op *op)
239{
240 struct plock_async_data *op_data = op->data;
241 struct file *file;
242 struct file_lock *fl;
243 struct file_lock *flc;
244 int (*notify)(struct file_lock *fl, int result) = NULL;
245 int rv = 0;
246
247 WARN_ON(!list_empty(&op->list));
248
249 /* check if the following 2 are still valid or make a copy */
250 file = op_data->file;
251 flc = &op_data->flc;
252 fl = op_data->fl;
253 notify = op_data->callback;
254
255 if (op->info.rv) {
256 notify(fl, op->info.rv);
257 goto out;
258 }
259
260 /* got fs lock; bookkeep locally as well: */
261 flc->fl_flags &= ~FL_SLEEP;
262 if (posix_lock_file(file, flc, NULL)) {
263 /*
264 * This can only happen in the case of kmalloc() failure.
265 * The filesystem's own lock is the authoritative lock,
266 * so a failure to get the lock locally is not a disaster.
267 * As long as the fs cannot reliably cancel locks (especially
268 * in a low-memory situation), we're better off ignoring
269 * this failure than trying to recover.
270 */
271 log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
272 (unsigned long long)op->info.number, file, fl);
273 }
274
275 rv = notify(fl, 0);
276 if (rv) {
277 /* XXX: We need to cancel the fs lock here: */
278 log_print("%s: lock granted after lock request failed; dangling lock!",
279 __func__);
280 goto out;
281 }
282
283out:
284 dlm_release_plock_op(op);
285 return rv;
286}
287
288int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
289 struct file_lock *fl)
290{
291 struct dlm_ls *ls;
292 struct plock_op *op;
293 int rv;
294 unsigned char fl_flags = fl->fl_flags;
295
296 ls = dlm_find_lockspace_local(lockspace);
297 if (!ls)
298 return -EINVAL;
299
300 op = kzalloc(sizeof(*op), GFP_NOFS);
301 if (!op) {
302 rv = -ENOMEM;
303 goto out;
304 }
305
306 /* cause the vfs unlock to return ENOENT if lock is not found */
307 fl->fl_flags |= FL_EXISTS;
308
309 rv = locks_lock_file_wait(file, fl);
310 if (rv == -ENOENT) {
311 rv = 0;
312 goto out_free;
313 }
314 if (rv < 0) {
315 log_error(ls, "dlm_posix_unlock: vfs unlock error %d %llx",
316 rv, (unsigned long long)number);
317 }
318
319 op->info.optype = DLM_PLOCK_OP_UNLOCK;
320 op->info.pid = fl->fl_pid;
321 op->info.fsid = ls->ls_global_id;
322 op->info.number = number;
323 op->info.start = fl->fl_start;
324 op->info.end = fl->fl_end;
325 op->info.owner = (__u64)(long)fl->fl_owner;
326
327 if (fl->fl_flags & FL_CLOSE) {
328 op->info.flags |= DLM_PLOCK_FL_CLOSE;
329 send_op(op);
330 rv = 0;
331 goto out;
332 }
333
334 send_op(op);
335 wait_event(recv_wq, (op->done != 0));
336
337 WARN_ON(!list_empty(&op->list));
338
339 rv = op->info.rv;
340
341 if (rv == -ENOENT)
342 rv = 0;
343
344out_free:
345 dlm_release_plock_op(op);
346out:
347 dlm_put_lockspace(ls);
348 fl->fl_flags = fl_flags;
349 return rv;
350}
351EXPORT_SYMBOL_GPL(dlm_posix_unlock);
352
353/*
354 * NOTE: This implementation can only handle async lock requests as nfs
355 * do it. It cannot handle cancellation of a pending lock request sitting
356 * in wait_event(), but for now only nfs is the only user local kernel
357 * user.
358 */
359int dlm_posix_cancel(dlm_lockspace_t *lockspace, u64 number, struct file *file,
360 struct file_lock *fl)
361{
362 struct dlm_plock_info info;
363 struct plock_op *op;
364 struct dlm_ls *ls;
365 int rv;
366
367 /* this only works for async request for now and nfs is the only
368 * kernel user right now.
369 */
370 if (WARN_ON_ONCE(!fl->fl_lmops || !fl->fl_lmops->lm_grant))
371 return -EOPNOTSUPP;
372
373 ls = dlm_find_lockspace_local(lockspace);
374 if (!ls)
375 return -EINVAL;
376
377 memset(&info, 0, sizeof(info));
378 info.pid = fl->fl_pid;
379 info.ex = (fl->fl_type == F_WRLCK);
380 info.fsid = ls->ls_global_id;
381 dlm_put_lockspace(ls);
382 info.number = number;
383 info.start = fl->fl_start;
384 info.end = fl->fl_end;
385 info.owner = (__u64)(long)fl->fl_owner;
386
387 rv = do_lock_cancel(&info);
388 switch (rv) {
389 case 0:
390 spin_lock(&ops_lock);
391 /* lock request to cancel must be on recv_list because
392 * do_lock_cancel() synchronizes it.
393 */
394 op = plock_lookup_waiter(&info);
395 if (WARN_ON_ONCE(!op)) {
396 spin_unlock(&ops_lock);
397 rv = -ENOLCK;
398 break;
399 }
400
401 list_del(&op->list);
402 spin_unlock(&ops_lock);
403 WARN_ON(op->info.optype != DLM_PLOCK_OP_LOCK);
404 op->data->callback(op->data->fl, -EINTR);
405 dlm_release_plock_op(op);
406 rv = -EINTR;
407 break;
408 case -ENOENT:
409 /* if cancel wasn't successful we probably were to late
410 * or it was a non-blocking lock request, so just unlock it.
411 */
412 rv = dlm_posix_unlock(lockspace, number, file, fl);
413 break;
414 default:
415 break;
416 }
417
418 return rv;
419}
420EXPORT_SYMBOL_GPL(dlm_posix_cancel);
421
422int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
423 struct file_lock *fl)
424{
425 struct dlm_ls *ls;
426 struct plock_op *op;
427 int rv;
428
429 ls = dlm_find_lockspace_local(lockspace);
430 if (!ls)
431 return -EINVAL;
432
433 op = kzalloc(sizeof(*op), GFP_NOFS);
434 if (!op) {
435 rv = -ENOMEM;
436 goto out;
437 }
438
439 op->info.optype = DLM_PLOCK_OP_GET;
440 op->info.pid = fl->fl_pid;
441 op->info.ex = (fl->fl_type == F_WRLCK);
442 op->info.fsid = ls->ls_global_id;
443 op->info.number = number;
444 op->info.start = fl->fl_start;
445 op->info.end = fl->fl_end;
446 op->info.owner = (__u64)(long)fl->fl_owner;
447
448 send_op(op);
449 wait_event(recv_wq, (op->done != 0));
450
451 WARN_ON(!list_empty(&op->list));
452
453 /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
454 -ENOENT if there are no locks on the file */
455
456 rv = op->info.rv;
457
458 fl->fl_type = F_UNLCK;
459 if (rv == -ENOENT)
460 rv = 0;
461 else if (rv > 0) {
462 locks_init_lock(fl);
463 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
464 fl->fl_flags = FL_POSIX;
465 fl->fl_pid = op->info.pid;
466 if (op->info.nodeid != dlm_our_nodeid())
467 fl->fl_pid = -fl->fl_pid;
468 fl->fl_start = op->info.start;
469 fl->fl_end = op->info.end;
470 rv = 0;
471 }
472
473 dlm_release_plock_op(op);
474out:
475 dlm_put_lockspace(ls);
476 return rv;
477}
478EXPORT_SYMBOL_GPL(dlm_posix_get);
479
480/* a read copies out one plock request from the send list */
481static ssize_t dev_read(struct file *file, char __user *u, size_t count,
482 loff_t *ppos)
483{
484 struct dlm_plock_info info;
485 struct plock_op *op = NULL;
486
487 if (count < sizeof(info))
488 return -EINVAL;
489
490 spin_lock(&ops_lock);
491 if (!list_empty(&send_list)) {
492 op = list_first_entry(&send_list, struct plock_op, list);
493 if (op->info.flags & DLM_PLOCK_FL_CLOSE)
494 list_del(&op->list);
495 else
496 list_move_tail(&op->list, &recv_list);
497 memcpy(&info, &op->info, sizeof(info));
498 }
499 spin_unlock(&ops_lock);
500
501 if (!op)
502 return -EAGAIN;
503
504 trace_dlm_plock_read(&info);
505
506 /* there is no need to get a reply from userspace for unlocks
507 that were generated by the vfs cleaning up for a close
508 (the process did not make an unlock call). */
509
510 if (op->info.flags & DLM_PLOCK_FL_CLOSE)
511 dlm_release_plock_op(op);
512
513 if (copy_to_user(u, &info, sizeof(info)))
514 return -EFAULT;
515 return sizeof(info);
516}
517
518/* a write copies in one plock result that should match a plock_op
519 on the recv list */
520static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
521 loff_t *ppos)
522{
523 struct plock_op *op = NULL, *iter;
524 struct dlm_plock_info info;
525 int do_callback = 0;
526
527 if (count != sizeof(info))
528 return -EINVAL;
529
530 if (copy_from_user(&info, u, sizeof(info)))
531 return -EFAULT;
532
533 trace_dlm_plock_write(&info);
534
535 if (check_version(&info))
536 return -EINVAL;
537
538 /*
539 * The results for waiting ops (SETLKW) can be returned in any
540 * order, so match all fields to find the op. The results for
541 * non-waiting ops are returned in the order that they were sent
542 * to userspace, so match the result with the first non-waiting op.
543 */
544 spin_lock(&ops_lock);
545 if (info.wait) {
546 op = plock_lookup_waiter(&info);
547 } else {
548 list_for_each_entry(iter, &recv_list, list) {
549 if (!iter->info.wait &&
550 iter->info.fsid == info.fsid) {
551 op = iter;
552 break;
553 }
554 }
555 }
556
557 if (op) {
558 /* Sanity check that op and info match. */
559 if (info.wait)
560 WARN_ON(op->info.optype != DLM_PLOCK_OP_LOCK);
561 else
562 WARN_ON(op->info.number != info.number ||
563 op->info.owner != info.owner ||
564 op->info.optype != info.optype);
565
566 list_del_init(&op->list);
567 memcpy(&op->info, &info, sizeof(info));
568 if (op->data)
569 do_callback = 1;
570 else
571 op->done = 1;
572 }
573 spin_unlock(&ops_lock);
574
575 if (op) {
576 if (do_callback)
577 dlm_plock_callback(op);
578 else
579 wake_up(&recv_wq);
580 } else
581 pr_debug("%s: no op %x %llx", __func__,
582 info.fsid, (unsigned long long)info.number);
583 return count;
584}
585
586static __poll_t dev_poll(struct file *file, poll_table *wait)
587{
588 __poll_t mask = 0;
589
590 poll_wait(file, &send_wq, wait);
591
592 spin_lock(&ops_lock);
593 if (!list_empty(&send_list))
594 mask = EPOLLIN | EPOLLRDNORM;
595 spin_unlock(&ops_lock);
596
597 return mask;
598}
599
600static const struct file_operations dev_fops = {
601 .read = dev_read,
602 .write = dev_write,
603 .poll = dev_poll,
604 .owner = THIS_MODULE,
605 .llseek = noop_llseek,
606};
607
608static struct miscdevice plock_dev_misc = {
609 .minor = MISC_DYNAMIC_MINOR,
610 .name = DLM_PLOCK_MISC_NAME,
611 .fops = &dev_fops
612};
613
614int dlm_plock_init(void)
615{
616 int rv;
617
618 rv = misc_register(&plock_dev_misc);
619 if (rv)
620 log_print("dlm_plock_init: misc_register failed %d", rv);
621 return rv;
622}
623
624void dlm_plock_exit(void)
625{
626 misc_deregister(&plock_dev_misc);
627 WARN_ON(!list_empty(&send_list));
628 WARN_ON(!list_empty(&recv_list));
629}
630