Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
[cris-mirror.git] / fs / dlm / plock.c
blob30d8b85febbf1eb413333bddac0b365b29b676d3
1 /*
2 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
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 */
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 #include <linux/slab.h>
16 #include "dlm_internal.h"
17 #include "lockspace.h"
19 static spinlock_t ops_lock;
20 static struct list_head send_list;
21 static struct list_head recv_list;
22 static wait_queue_head_t send_wq;
23 static wait_queue_head_t recv_wq;
25 struct plock_op {
26 struct list_head list;
27 int done;
28 struct dlm_plock_info info;
31 struct plock_xop {
32 struct plock_op xop;
33 void *callback;
34 void *fl;
35 void *file;
36 struct file_lock flc;
40 static inline void set_version(struct dlm_plock_info *info)
42 info->version[0] = DLM_PLOCK_VERSION_MAJOR;
43 info->version[1] = DLM_PLOCK_VERSION_MINOR;
44 info->version[2] = DLM_PLOCK_VERSION_PATCH;
47 static int check_version(struct dlm_plock_info *info)
49 if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
50 (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
51 log_print("plock device version mismatch: "
52 "kernel (%u.%u.%u), user (%u.%u.%u)",
53 DLM_PLOCK_VERSION_MAJOR,
54 DLM_PLOCK_VERSION_MINOR,
55 DLM_PLOCK_VERSION_PATCH,
56 info->version[0],
57 info->version[1],
58 info->version[2]);
59 return -EINVAL;
61 return 0;
64 static void send_op(struct plock_op *op)
66 set_version(&op->info);
67 INIT_LIST_HEAD(&op->list);
68 spin_lock(&ops_lock);
69 list_add_tail(&op->list, &send_list);
70 spin_unlock(&ops_lock);
71 wake_up(&send_wq);
74 int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
75 int cmd, struct file_lock *fl)
77 struct dlm_ls *ls;
78 struct plock_op *op;
79 struct plock_xop *xop;
80 int rv;
82 ls = dlm_find_lockspace_local(lockspace);
83 if (!ls)
84 return -EINVAL;
86 xop = kzalloc(sizeof(*xop), GFP_NOFS);
87 if (!xop) {
88 rv = -ENOMEM;
89 goto out;
92 op = &xop->xop;
93 op->info.optype = DLM_PLOCK_OP_LOCK;
94 op->info.pid = fl->fl_pid;
95 op->info.ex = (fl->fl_type == F_WRLCK);
96 op->info.wait = IS_SETLKW(cmd);
97 op->info.fsid = ls->ls_global_id;
98 op->info.number = number;
99 op->info.start = fl->fl_start;
100 op->info.end = fl->fl_end;
101 if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
102 /* fl_owner is lockd which doesn't distinguish
103 processes on the nfs client */
104 op->info.owner = (__u64) fl->fl_pid;
105 xop->callback = fl->fl_lmops->fl_grant;
106 locks_init_lock(&xop->flc);
107 locks_copy_lock(&xop->flc, fl);
108 xop->fl = fl;
109 xop->file = file;
110 } else {
111 op->info.owner = (__u64)(long) fl->fl_owner;
112 xop->callback = NULL;
115 send_op(op);
117 if (xop->callback == NULL)
118 wait_event(recv_wq, (op->done != 0));
119 else {
120 rv = FILE_LOCK_DEFERRED;
121 goto out;
124 spin_lock(&ops_lock);
125 if (!list_empty(&op->list)) {
126 log_error(ls, "dlm_posix_lock: op on list %llx",
127 (unsigned long long)number);
128 list_del(&op->list);
130 spin_unlock(&ops_lock);
132 rv = op->info.rv;
134 if (!rv) {
135 if (posix_lock_file_wait(file, fl) < 0)
136 log_error(ls, "dlm_posix_lock: vfs lock error %llx",
137 (unsigned long long)number);
140 kfree(xop);
141 out:
142 dlm_put_lockspace(ls);
143 return rv;
145 EXPORT_SYMBOL_GPL(dlm_posix_lock);
147 /* Returns failure iff a successful lock operation should be canceled */
148 static int dlm_plock_callback(struct plock_op *op)
150 struct file *file;
151 struct file_lock *fl;
152 struct file_lock *flc;
153 int (*notify)(void *, void *, int) = NULL;
154 struct plock_xop *xop = (struct plock_xop *)op;
155 int rv = 0;
157 spin_lock(&ops_lock);
158 if (!list_empty(&op->list)) {
159 log_print("dlm_plock_callback: op on list %llx",
160 (unsigned long long)op->info.number);
161 list_del(&op->list);
163 spin_unlock(&ops_lock);
165 /* check if the following 2 are still valid or make a copy */
166 file = xop->file;
167 flc = &xop->flc;
168 fl = xop->fl;
169 notify = xop->callback;
171 if (op->info.rv) {
172 notify(fl, NULL, op->info.rv);
173 goto out;
176 /* got fs lock; bookkeep locally as well: */
177 flc->fl_flags &= ~FL_SLEEP;
178 if (posix_lock_file(file, flc, NULL)) {
180 * This can only happen in the case of kmalloc() failure.
181 * The filesystem's own lock is the authoritative lock,
182 * so a failure to get the lock locally is not a disaster.
183 * As long as the fs cannot reliably cancel locks (especially
184 * in a low-memory situation), we're better off ignoring
185 * this failure than trying to recover.
187 log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
188 (unsigned long long)op->info.number, file, fl);
191 rv = notify(fl, NULL, 0);
192 if (rv) {
193 /* XXX: We need to cancel the fs lock here: */
194 log_print("dlm_plock_callback: lock granted after lock request "
195 "failed; dangling lock!\n");
196 goto out;
199 out:
200 kfree(xop);
201 return rv;
204 int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
205 struct file_lock *fl)
207 struct dlm_ls *ls;
208 struct plock_op *op;
209 int rv;
211 ls = dlm_find_lockspace_local(lockspace);
212 if (!ls)
213 return -EINVAL;
215 op = kzalloc(sizeof(*op), GFP_NOFS);
216 if (!op) {
217 rv = -ENOMEM;
218 goto out;
221 if (posix_lock_file_wait(file, fl) < 0)
222 log_error(ls, "dlm_posix_unlock: vfs unlock error %llx",
223 (unsigned long long)number);
225 op->info.optype = DLM_PLOCK_OP_UNLOCK;
226 op->info.pid = fl->fl_pid;
227 op->info.fsid = ls->ls_global_id;
228 op->info.number = number;
229 op->info.start = fl->fl_start;
230 op->info.end = fl->fl_end;
231 if (fl->fl_lmops && fl->fl_lmops->fl_grant)
232 op->info.owner = (__u64) fl->fl_pid;
233 else
234 op->info.owner = (__u64)(long) fl->fl_owner;
236 send_op(op);
237 wait_event(recv_wq, (op->done != 0));
239 spin_lock(&ops_lock);
240 if (!list_empty(&op->list)) {
241 log_error(ls, "dlm_posix_unlock: op on list %llx",
242 (unsigned long long)number);
243 list_del(&op->list);
245 spin_unlock(&ops_lock);
247 rv = op->info.rv;
249 if (rv == -ENOENT)
250 rv = 0;
252 kfree(op);
253 out:
254 dlm_put_lockspace(ls);
255 return rv;
257 EXPORT_SYMBOL_GPL(dlm_posix_unlock);
259 int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
260 struct file_lock *fl)
262 struct dlm_ls *ls;
263 struct plock_op *op;
264 int rv;
266 ls = dlm_find_lockspace_local(lockspace);
267 if (!ls)
268 return -EINVAL;
270 op = kzalloc(sizeof(*op), GFP_NOFS);
271 if (!op) {
272 rv = -ENOMEM;
273 goto out;
276 op->info.optype = DLM_PLOCK_OP_GET;
277 op->info.pid = fl->fl_pid;
278 op->info.ex = (fl->fl_type == F_WRLCK);
279 op->info.fsid = ls->ls_global_id;
280 op->info.number = number;
281 op->info.start = fl->fl_start;
282 op->info.end = fl->fl_end;
283 if (fl->fl_lmops && fl->fl_lmops->fl_grant)
284 op->info.owner = (__u64) fl->fl_pid;
285 else
286 op->info.owner = (__u64)(long) fl->fl_owner;
288 send_op(op);
289 wait_event(recv_wq, (op->done != 0));
291 spin_lock(&ops_lock);
292 if (!list_empty(&op->list)) {
293 log_error(ls, "dlm_posix_get: op on list %llx",
294 (unsigned long long)number);
295 list_del(&op->list);
297 spin_unlock(&ops_lock);
299 /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
300 -ENOENT if there are no locks on the file */
302 rv = op->info.rv;
304 fl->fl_type = F_UNLCK;
305 if (rv == -ENOENT)
306 rv = 0;
307 else if (rv > 0) {
308 locks_init_lock(fl);
309 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
310 fl->fl_flags = FL_POSIX;
311 fl->fl_pid = op->info.pid;
312 fl->fl_start = op->info.start;
313 fl->fl_end = op->info.end;
314 rv = 0;
317 kfree(op);
318 out:
319 dlm_put_lockspace(ls);
320 return rv;
322 EXPORT_SYMBOL_GPL(dlm_posix_get);
324 /* a read copies out one plock request from the send list */
325 static ssize_t dev_read(struct file *file, char __user *u, size_t count,
326 loff_t *ppos)
328 struct dlm_plock_info info;
329 struct plock_op *op = NULL;
331 if (count < sizeof(info))
332 return -EINVAL;
334 spin_lock(&ops_lock);
335 if (!list_empty(&send_list)) {
336 op = list_entry(send_list.next, struct plock_op, list);
337 list_move(&op->list, &recv_list);
338 memcpy(&info, &op->info, sizeof(info));
340 spin_unlock(&ops_lock);
342 if (!op)
343 return -EAGAIN;
345 if (copy_to_user(u, &info, sizeof(info)))
346 return -EFAULT;
347 return sizeof(info);
350 /* a write copies in one plock result that should match a plock_op
351 on the recv list */
352 static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
353 loff_t *ppos)
355 struct dlm_plock_info info;
356 struct plock_op *op;
357 int found = 0, do_callback = 0;
359 if (count != sizeof(info))
360 return -EINVAL;
362 if (copy_from_user(&info, u, sizeof(info)))
363 return -EFAULT;
365 if (check_version(&info))
366 return -EINVAL;
368 spin_lock(&ops_lock);
369 list_for_each_entry(op, &recv_list, list) {
370 if (op->info.fsid == info.fsid &&
371 op->info.number == info.number &&
372 op->info.owner == info.owner) {
373 struct plock_xop *xop = (struct plock_xop *)op;
374 list_del_init(&op->list);
375 memcpy(&op->info, &info, sizeof(info));
376 if (xop->callback)
377 do_callback = 1;
378 else
379 op->done = 1;
380 found = 1;
381 break;
384 spin_unlock(&ops_lock);
386 if (found) {
387 if (do_callback)
388 dlm_plock_callback(op);
389 else
390 wake_up(&recv_wq);
391 } else
392 log_print("dev_write no op %x %llx", info.fsid,
393 (unsigned long long)info.number);
394 return count;
397 static unsigned int dev_poll(struct file *file, poll_table *wait)
399 unsigned int mask = 0;
401 poll_wait(file, &send_wq, wait);
403 spin_lock(&ops_lock);
404 if (!list_empty(&send_list))
405 mask = POLLIN | POLLRDNORM;
406 spin_unlock(&ops_lock);
408 return mask;
411 static const struct file_operations dev_fops = {
412 .read = dev_read,
413 .write = dev_write,
414 .poll = dev_poll,
415 .owner = THIS_MODULE,
416 .llseek = noop_llseek,
419 static struct miscdevice plock_dev_misc = {
420 .minor = MISC_DYNAMIC_MINOR,
421 .name = DLM_PLOCK_MISC_NAME,
422 .fops = &dev_fops
425 int dlm_plock_init(void)
427 int rv;
429 spin_lock_init(&ops_lock);
430 INIT_LIST_HEAD(&send_list);
431 INIT_LIST_HEAD(&recv_list);
432 init_waitqueue_head(&send_wq);
433 init_waitqueue_head(&recv_wq);
435 rv = misc_register(&plock_dev_misc);
436 if (rv)
437 log_print("dlm_plock_init: misc_register failed %d", rv);
438 return rv;
441 void dlm_plock_exit(void)
443 if (misc_deregister(&plock_dev_misc) < 0)
444 log_print("dlm_plock_exit: misc_deregister failed");