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-rw-r--r--fs/dlm/plock.c439
1 files changed, 439 insertions, 0 deletions
diff --git a/fs/dlm/plock.c b/fs/dlm/plock.c
new file mode 100644
index 000000000000..d6d6e370f89c
--- /dev/null
+++ b/fs/dlm/plock.c
@@ -0,0 +1,439 @@
1/*
2 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
3 *
4 * This copyrighted material is made available to anyone wishing to use,
5 * modify, copy, or redistribute it subject to the terms and conditions
6 * of the GNU General Public License version 2.
7 */
8
9#include <linux/fs.h>
10#include <linux/miscdevice.h>
11#include <linux/poll.h>
12#include <linux/dlm.h>
13#include <linux/dlm_plock.h>
14
15#include "dlm_internal.h"
16#include "lockspace.h"
17
18static spinlock_t ops_lock;
19static struct list_head send_list;
20static struct list_head recv_list;
21static wait_queue_head_t send_wq;
22static wait_queue_head_t recv_wq;
23
24struct plock_op {
25 struct list_head list;
26 int done;
27 struct dlm_plock_info info;
28};
29
30struct plock_xop {
31 struct plock_op xop;
32 void *callback;
33 void *fl;
34 void *file;
35 struct file_lock flc;
36};
37
38
39static inline void set_version(struct dlm_plock_info *info)
40{
41 info->version[0] = DLM_PLOCK_VERSION_MAJOR;
42 info->version[1] = DLM_PLOCK_VERSION_MINOR;
43 info->version[2] = DLM_PLOCK_VERSION_PATCH;
44}
45
46static int check_version(struct dlm_plock_info *info)
47{
48 if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
49 (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
50 log_print("plock device version mismatch: "
51 "kernel (%u.%u.%u), user (%u.%u.%u)",
52 DLM_PLOCK_VERSION_MAJOR,
53 DLM_PLOCK_VERSION_MINOR,
54 DLM_PLOCK_VERSION_PATCH,
55 info->version[0],
56 info->version[1],
57 info->version[2]);
58 return -EINVAL;
59 }
60 return 0;
61}
62
63static void send_op(struct plock_op *op)
64{
65 set_version(&op->info);
66 INIT_LIST_HEAD(&op->list);
67 spin_lock(&ops_lock);
68 list_add_tail(&op->list, &send_list);
69 spin_unlock(&ops_lock);
70 wake_up(&send_wq);
71}
72
73int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
74 int cmd, struct file_lock *fl)
75{
76 struct dlm_ls *ls;
77 struct plock_op *op;
78 struct plock_xop *xop;
79 int rv;
80
81 ls = dlm_find_lockspace_local(lockspace);
82 if (!ls)
83 return -EINVAL;
84
85 xop = kzalloc(sizeof(*xop), GFP_KERNEL);
86 if (!xop) {
87 rv = -ENOMEM;
88 goto out;
89 }
90
91 op = &xop->xop;
92 op->info.optype = DLM_PLOCK_OP_LOCK;
93 op->info.pid = fl->fl_pid;
94 op->info.ex = (fl->fl_type == F_WRLCK);
95 op->info.wait = IS_SETLKW(cmd);
96 op->info.fsid = ls->ls_global_id;
97 op->info.number = number;
98 op->info.start = fl->fl_start;
99 op->info.end = fl->fl_end;
100 if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
101 /* fl_owner is lockd which doesn't distinguish
102 processes on the nfs client */
103 op->info.owner = (__u64) fl->fl_pid;
104 xop->callback = fl->fl_lmops->fl_grant;
105 locks_init_lock(&xop->flc);
106 locks_copy_lock(&xop->flc, fl);
107 xop->fl = fl;
108 xop->file = file;
109 } else {
110 op->info.owner = (__u64)(long) fl->fl_owner;
111 xop->callback = NULL;
112 }
113
114 send_op(op);
115
116 if (xop->callback == NULL)
117 wait_event(recv_wq, (op->done != 0));
118 else {
119 rv = -EINPROGRESS;
120 goto out;
121 }
122
123 spin_lock(&ops_lock);
124 if (!list_empty(&op->list)) {
125 log_error(ls, "dlm_posix_lock: op on list %llx",
126 (unsigned long long)number);
127 list_del(&op->list);
128 }
129 spin_unlock(&ops_lock);
130
131 rv = op->info.rv;
132
133 if (!rv) {
134 if (posix_lock_file_wait(file, fl) < 0)
135 log_error(ls, "dlm_posix_lock: vfs lock error %llx",
136 (unsigned long long)number);
137 }
138
139 kfree(xop);
140out:
141 dlm_put_lockspace(ls);
142 return rv;
143}
144EXPORT_SYMBOL_GPL(dlm_posix_lock);
145
146/* Returns failure iff a succesful lock operation should be canceled */
147static int dlm_plock_callback(struct plock_op *op)
148{
149 struct file *file;
150 struct file_lock *fl;
151 struct file_lock *flc;
152 int (*notify)(void *, void *, int) = NULL;
153 struct plock_xop *xop = (struct plock_xop *)op;
154 int rv = 0;
155
156 spin_lock(&ops_lock);
157 if (!list_empty(&op->list)) {
158 log_print("dlm_plock_callback: op on list %llx",
159 (unsigned long long)op->info.number);
160 list_del(&op->list);
161 }
162 spin_unlock(&ops_lock);
163
164 /* check if the following 2 are still valid or make a copy */
165 file = xop->file;
166 flc = &xop->flc;
167 fl = xop->fl;
168 notify = xop->callback;
169
170 if (op->info.rv) {
171 notify(flc, NULL, op->info.rv);
172 goto out;
173 }
174
175 /* got fs lock; bookkeep locally as well: */
176 flc->fl_flags &= ~FL_SLEEP;
177 if (posix_lock_file(file, flc, NULL)) {
178 /*
179 * This can only happen in the case of kmalloc() failure.
180 * The filesystem's own lock is the authoritative lock,
181 * so a failure to get the lock locally is not a disaster.
182 * As long as the fs cannot reliably cancel locks (especially
183 * in a low-memory situation), we're better off ignoring
184 * this failure than trying to recover.
185 */
186 log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
187 (unsigned long long)op->info.number, file, fl);
188 }
189
190 rv = notify(flc, NULL, 0);
191 if (rv) {
192 /* XXX: We need to cancel the fs lock here: */
193 log_print("dlm_plock_callback: lock granted after lock request "
194 "failed; dangling lock!\n");
195 goto out;
196 }
197
198out:
199 kfree(xop);
200 return rv;
201}
202
203int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
204 struct file_lock *fl)
205{
206 struct dlm_ls *ls;
207 struct plock_op *op;
208 int rv;
209
210 ls = dlm_find_lockspace_local(lockspace);
211 if (!ls)
212 return -EINVAL;
213
214 op = kzalloc(sizeof(*op), GFP_KERNEL);
215 if (!op) {
216 rv = -ENOMEM;
217 goto out;
218 }
219
220 if (posix_lock_file_wait(file, fl) < 0)
221 log_error(ls, "dlm_posix_unlock: vfs unlock error %llx",
222 (unsigned long long)number);
223
224 op->info.optype = DLM_PLOCK_OP_UNLOCK;
225 op->info.pid = fl->fl_pid;
226 op->info.fsid = ls->ls_global_id;
227 op->info.number = number;
228 op->info.start = fl->fl_start;
229 op->info.end = fl->fl_end;
230 if (fl->fl_lmops && fl->fl_lmops->fl_grant)
231 op->info.owner = (__u64) fl->fl_pid;
232 else
233 op->info.owner = (__u64)(long) fl->fl_owner;
234
235 send_op(op);
236 wait_event(recv_wq, (op->done != 0));
237
238 spin_lock(&ops_lock);
239 if (!list_empty(&op->list)) {
240 log_error(ls, "dlm_posix_unlock: op on list %llx",
241 (unsigned long long)number);
242 list_del(&op->list);
243 }
244 spin_unlock(&ops_lock);
245
246 rv = op->info.rv;
247
248 if (rv == -ENOENT)
249 rv = 0;
250
251 kfree(op);
252out:
253 dlm_put_lockspace(ls);
254 return rv;
255}
256EXPORT_SYMBOL_GPL(dlm_posix_unlock);
257
258int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
259 struct file_lock *fl)
260{
261 struct dlm_ls *ls;
262 struct plock_op *op;
263 int rv;
264
265 ls = dlm_find_lockspace_local(lockspace);
266 if (!ls)
267 return -EINVAL;
268
269 op = kzalloc(sizeof(*op), GFP_KERNEL);
270 if (!op) {
271 rv = -ENOMEM;
272 goto out;
273 }
274
275 op->info.optype = DLM_PLOCK_OP_GET;
276 op->info.pid = fl->fl_pid;
277 op->info.ex = (fl->fl_type == F_WRLCK);
278 op->info.fsid = ls->ls_global_id;
279 op->info.number = number;
280 op->info.start = fl->fl_start;
281 op->info.end = fl->fl_end;
282 if (fl->fl_lmops && fl->fl_lmops->fl_grant)
283 op->info.owner = (__u64) fl->fl_pid;
284 else
285 op->info.owner = (__u64)(long) fl->fl_owner;
286
287 send_op(op);
288 wait_event(recv_wq, (op->done != 0));
289
290 spin_lock(&ops_lock);
291 if (!list_empty(&op->list)) {
292 log_error(ls, "dlm_posix_get: op on list %llx",
293 (unsigned long long)number);
294 list_del(&op->list);
295 }
296 spin_unlock(&ops_lock);
297
298 /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
299 -ENOENT if there are no locks on the file */
300
301 rv = op->info.rv;
302
303 fl->fl_type = F_UNLCK;
304 if (rv == -ENOENT)
305 rv = 0;
306 else if (rv > 0) {
307 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
308 fl->fl_pid = op->info.pid;
309 fl->fl_start = op->info.start;
310 fl->fl_end = op->info.end;
311 rv = 0;
312 }
313
314 kfree(op);
315out:
316 dlm_put_lockspace(ls);
317 return rv;
318}
319EXPORT_SYMBOL_GPL(dlm_posix_get);
320
321/* a read copies out one plock request from the send list */
322static ssize_t dev_read(struct file *file, char __user *u, size_t count,
323 loff_t *ppos)
324{
325 struct dlm_plock_info info;
326 struct plock_op *op = NULL;
327
328 if (count < sizeof(info))
329 return -EINVAL;
330
331 spin_lock(&ops_lock);
332 if (!list_empty(&send_list)) {
333 op = list_entry(send_list.next, struct plock_op, list);
334 list_move(&op->list, &recv_list);
335 memcpy(&info, &op->info, sizeof(info));
336 }
337 spin_unlock(&ops_lock);
338
339 if (!op)
340 return -EAGAIN;
341
342 if (copy_to_user(u, &info, sizeof(info)))
343 return -EFAULT;
344 return sizeof(info);
345}
346
347/* a write copies in one plock result that should match a plock_op
348 on the recv list */
349static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
350 loff_t *ppos)
351{
352 struct dlm_plock_info info;
353 struct plock_op *op;
354 int found = 0;
355
356 if (count != sizeof(info))
357 return -EINVAL;
358
359 if (copy_from_user(&info, u, sizeof(info)))
360 return -EFAULT;
361
362 if (check_version(&info))
363 return -EINVAL;
364
365 spin_lock(&ops_lock);
366 list_for_each_entry(op, &recv_list, list) {
367 if (op->info.fsid == info.fsid && op->info.number == info.number &&
368 op->info.owner == info.owner) {
369 list_del_init(&op->list);
370 found = 1;
371 op->done = 1;
372 memcpy(&op->info, &info, sizeof(info));
373 break;
374 }
375 }
376 spin_unlock(&ops_lock);
377
378 if (found) {
379 struct plock_xop *xop;
380 xop = (struct plock_xop *)op;
381 if (xop->callback)
382 count = dlm_plock_callback(op);
383 else
384 wake_up(&recv_wq);
385 } else
386 log_print("dev_write no op %x %llx", info.fsid,
387 (unsigned long long)info.number);
388 return count;
389}
390
391static unsigned int dev_poll(struct file *file, poll_table *wait)
392{
393 unsigned int mask = 0;
394
395 poll_wait(file, &send_wq, wait);
396
397 spin_lock(&ops_lock);
398 if (!list_empty(&send_list))
399 mask = POLLIN | POLLRDNORM;
400 spin_unlock(&ops_lock);
401
402 return mask;
403}
404
405static const struct file_operations dev_fops = {
406 .read = dev_read,
407 .write = dev_write,
408 .poll = dev_poll,
409 .owner = THIS_MODULE
410};
411
412static struct miscdevice plock_dev_misc = {
413 .minor = MISC_DYNAMIC_MINOR,
414 .name = DLM_PLOCK_MISC_NAME,
415 .fops = &dev_fops
416};
417
418int dlm_plock_init(void)
419{
420 int rv;
421
422 spin_lock_init(&ops_lock);
423 INIT_LIST_HEAD(&send_list);
424 INIT_LIST_HEAD(&recv_list);
425 init_waitqueue_head(&send_wq);
426 init_waitqueue_head(&recv_wq);
427
428 rv = misc_register(&plock_dev_misc);
429 if (rv)
430 log_print("dlm_plock_init: misc_register failed %d", rv);
431 return rv;
432}
433
434void dlm_plock_exit(void)
435{
436 if (misc_deregister(&plock_dev_misc) < 0)
437 log_print("dlm_plock_exit: misc_deregister failed");
438}
439
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