blob: d45c02db694393a1989119ec510709b653dd76e9 [file] [log] [blame]
David Teigland869d81d2006-01-17 08:47:12 +00001/*
David Teigland24022112008-03-14 15:09:15 -05002 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
David Teigland869d81d2006-01-17 08:47:12 +00003 *
4 * This copyrighted material is made available to anyone wishing to use,
5 * modify, copy, or redistribute it subject to the terms and conditions
Steven Whitehousee9fc2aa2006-09-01 11:05:15 -04006 * of the GNU General Public License version 2.
David Teigland869d81d2006-01-17 08:47:12 +00007 */
8
David Teigland24022112008-03-14 15:09:15 -05009#include <linux/fs.h>
David Teigland869d81d2006-01-17 08:47:12 +000010#include <linux/miscdevice.h>
Al Virobd01f842006-10-19 17:23:57 -040011#include <linux/poll.h>
David Teigland24022112008-03-14 15:09:15 -050012#include <linux/dlm.h>
13#include <linux/dlm_plock.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090014#include <linux/slab.h>
David Teigland869d81d2006-01-17 08:47:12 +000015
David Teigland24022112008-03-14 15:09:15 -050016#include "dlm_internal.h"
17#include "lockspace.h"
David Teigland869d81d2006-01-17 08:47:12 +000018
19static spinlock_t ops_lock;
20static struct list_head send_list;
21static struct list_head recv_list;
22static wait_queue_head_t send_wq;
23static wait_queue_head_t recv_wq;
24
25struct plock_op {
26 struct list_head list;
27 int done;
David Teigland24022112008-03-14 15:09:15 -050028 struct dlm_plock_info info;
David Teigland869d81d2006-01-17 08:47:12 +000029};
30
Marc Eshel586759f2006-11-14 16:37:25 -050031struct plock_xop {
32 struct plock_op xop;
33 void *callback;
34 void *fl;
35 void *file;
36 struct file_lock flc;
37};
38
39
David Teigland24022112008-03-14 15:09:15 -050040static inline void set_version(struct dlm_plock_info *info)
David Teigland869d81d2006-01-17 08:47:12 +000041{
David Teigland24022112008-03-14 15:09:15 -050042 info->version[0] = DLM_PLOCK_VERSION_MAJOR;
43 info->version[1] = DLM_PLOCK_VERSION_MINOR;
44 info->version[2] = DLM_PLOCK_VERSION_PATCH;
David Teigland869d81d2006-01-17 08:47:12 +000045}
46
David Teigland24022112008-03-14 15:09:15 -050047static int check_version(struct dlm_plock_info *info)
David Teigland869d81d2006-01-17 08:47:12 +000048{
David Teigland24022112008-03-14 15:09:15 -050049 if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
50 (DLM_PLOCK_VERSION_MINOR < info->version[1])) {
51 log_print("plock device version mismatch: "
David Teigland869d81d2006-01-17 08:47:12 +000052 "kernel (%u.%u.%u), user (%u.%u.%u)",
David Teigland24022112008-03-14 15:09:15 -050053 DLM_PLOCK_VERSION_MAJOR,
54 DLM_PLOCK_VERSION_MINOR,
55 DLM_PLOCK_VERSION_PATCH,
David Teigland869d81d2006-01-17 08:47:12 +000056 info->version[0],
57 info->version[1],
58 info->version[2]);
59 return -EINVAL;
60 }
61 return 0;
62}
63
64static void send_op(struct plock_op *op)
65{
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);
72}
73
David Teigland24022112008-03-14 15:09:15 -050074int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
75 int cmd, struct file_lock *fl)
David Teigland869d81d2006-01-17 08:47:12 +000076{
David Teigland24022112008-03-14 15:09:15 -050077 struct dlm_ls *ls;
David Teigland869d81d2006-01-17 08:47:12 +000078 struct plock_op *op;
Marc Eshel586759f2006-11-14 16:37:25 -050079 struct plock_xop *xop;
David Teigland869d81d2006-01-17 08:47:12 +000080 int rv;
81
David Teigland24022112008-03-14 15:09:15 -050082 ls = dlm_find_lockspace_local(lockspace);
83 if (!ls)
84 return -EINVAL;
85
David Teigland573c24c2009-11-30 16:34:43 -060086 xop = kzalloc(sizeof(*xop), GFP_NOFS);
David Teigland24022112008-03-14 15:09:15 -050087 if (!xop) {
88 rv = -ENOMEM;
89 goto out;
90 }
David Teigland869d81d2006-01-17 08:47:12 +000091
Marc Eshel586759f2006-11-14 16:37:25 -050092 op = &xop->xop;
David Teigland24022112008-03-14 15:09:15 -050093 op->info.optype = DLM_PLOCK_OP_LOCK;
David Teigland3a2a9c92006-04-25 15:45:51 -040094 op->info.pid = fl->fl_pid;
David Teigland869d81d2006-01-17 08:47:12 +000095 op->info.ex = (fl->fl_type == F_WRLCK);
96 op->info.wait = IS_SETLKW(cmd);
David Teigland24022112008-03-14 15:09:15 -050097 op->info.fsid = ls->ls_global_id;
98 op->info.number = number;
David Teigland869d81d2006-01-17 08:47:12 +000099 op->info.start = fl->fl_start;
100 op->info.end = fl->fl_end;
Marc Eshel586759f2006-11-14 16:37:25 -0500101 if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
David Teigland2066b582007-12-06 09:35:25 -0600102 /* fl_owner is lockd which doesn't distinguish
103 processes on the nfs client */
104 op->info.owner = (__u64) fl->fl_pid;
Marc Eshel586759f2006-11-14 16:37:25 -0500105 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;
David Teigland2066b582007-12-06 09:35:25 -0600110 } else {
111 op->info.owner = (__u64)(long) fl->fl_owner;
Marc Eshel586759f2006-11-14 16:37:25 -0500112 xop->callback = NULL;
David Teigland2066b582007-12-06 09:35:25 -0600113 }
David Teigland869d81d2006-01-17 08:47:12 +0000114
115 send_op(op);
Marc Eshel586759f2006-11-14 16:37:25 -0500116
117 if (xop->callback == NULL)
118 wait_event(recv_wq, (op->done != 0));
David Teigland24022112008-03-14 15:09:15 -0500119 else {
Miklos Szeredibde74e42008-07-25 01:48:57 -0700120 rv = FILE_LOCK_DEFERRED;
David Teigland24022112008-03-14 15:09:15 -0500121 goto out;
122 }
David Teigland869d81d2006-01-17 08:47:12 +0000123
124 spin_lock(&ops_lock);
125 if (!list_empty(&op->list)) {
David Teigland24022112008-03-14 15:09:15 -0500126 log_error(ls, "dlm_posix_lock: op on list %llx",
127 (unsigned long long)number);
David Teigland869d81d2006-01-17 08:47:12 +0000128 list_del(&op->list);
129 }
130 spin_unlock(&ops_lock);
131
132 rv = op->info.rv;
133
134 if (!rv) {
135 if (posix_lock_file_wait(file, fl) < 0)
David Teigland24022112008-03-14 15:09:15 -0500136 log_error(ls, "dlm_posix_lock: vfs lock error %llx",
137 (unsigned long long)number);
David Teigland869d81d2006-01-17 08:47:12 +0000138 }
139
Marc Eshel586759f2006-11-14 16:37:25 -0500140 kfree(xop);
David Teigland24022112008-03-14 15:09:15 -0500141out:
142 dlm_put_lockspace(ls);
Marc Eshel586759f2006-11-14 16:37:25 -0500143 return rv;
144}
David Teigland24022112008-03-14 15:09:15 -0500145EXPORT_SYMBOL_GPL(dlm_posix_lock);
Marc Eshel586759f2006-11-14 16:37:25 -0500146
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200147/* Returns failure iff a successful lock operation should be canceled */
David Teigland24022112008-03-14 15:09:15 -0500148static int dlm_plock_callback(struct plock_op *op)
Marc Eshel586759f2006-11-14 16:37:25 -0500149{
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;
156
157 spin_lock(&ops_lock);
158 if (!list_empty(&op->list)) {
David Teigland24022112008-03-14 15:09:15 -0500159 log_print("dlm_plock_callback: op on list %llx",
160 (unsigned long long)op->info.number);
Marc Eshel586759f2006-11-14 16:37:25 -0500161 list_del(&op->list);
162 }
163 spin_unlock(&ops_lock);
164
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;
170
171 if (op->info.rv) {
David Teigland24179f42009-01-19 13:13:33 -0600172 notify(fl, NULL, op->info.rv);
Marc Eshel586759f2006-11-14 16:37:25 -0500173 goto out;
174 }
175
176 /* got fs lock; bookkeep locally as well: */
177 flc->fl_flags &= ~FL_SLEEP;
178 if (posix_lock_file(file, flc, NULL)) {
179 /*
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.
David Teigland24022112008-03-14 15:09:15 -0500183 * As long as the fs cannot reliably cancel locks (especially
Marc Eshel586759f2006-11-14 16:37:25 -0500184 * in a low-memory situation), we're better off ignoring
185 * this failure than trying to recover.
186 */
David Teigland24022112008-03-14 15:09:15 -0500187 log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
188 (unsigned long long)op->info.number, file, fl);
Marc Eshel586759f2006-11-14 16:37:25 -0500189 }
190
David Teigland24179f42009-01-19 13:13:33 -0600191 rv = notify(fl, NULL, 0);
Marc Eshel586759f2006-11-14 16:37:25 -0500192 if (rv) {
193 /* XXX: We need to cancel the fs lock here: */
David Teigland24022112008-03-14 15:09:15 -0500194 log_print("dlm_plock_callback: lock granted after lock request "
195 "failed; dangling lock!\n");
Marc Eshel586759f2006-11-14 16:37:25 -0500196 goto out;
197 }
198
199out:
200 kfree(xop);
David Teigland869d81d2006-01-17 08:47:12 +0000201 return rv;
202}
203
David Teigland24022112008-03-14 15:09:15 -0500204int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
205 struct file_lock *fl)
David Teigland869d81d2006-01-17 08:47:12 +0000206{
David Teigland24022112008-03-14 15:09:15 -0500207 struct dlm_ls *ls;
David Teigland869d81d2006-01-17 08:47:12 +0000208 struct plock_op *op;
209 int rv;
210
David Teigland24022112008-03-14 15:09:15 -0500211 ls = dlm_find_lockspace_local(lockspace);
212 if (!ls)
213 return -EINVAL;
214
David Teigland573c24c2009-11-30 16:34:43 -0600215 op = kzalloc(sizeof(*op), GFP_NOFS);
David Teigland24022112008-03-14 15:09:15 -0500216 if (!op) {
217 rv = -ENOMEM;
218 goto out;
219 }
David Teigland869d81d2006-01-17 08:47:12 +0000220
221 if (posix_lock_file_wait(file, fl) < 0)
David Teigland24022112008-03-14 15:09:15 -0500222 log_error(ls, "dlm_posix_unlock: vfs unlock error %llx",
223 (unsigned long long)number);
David Teigland869d81d2006-01-17 08:47:12 +0000224
David Teigland24022112008-03-14 15:09:15 -0500225 op->info.optype = DLM_PLOCK_OP_UNLOCK;
David Teigland3a2a9c92006-04-25 15:45:51 -0400226 op->info.pid = fl->fl_pid;
David Teigland24022112008-03-14 15:09:15 -0500227 op->info.fsid = ls->ls_global_id;
228 op->info.number = number;
David Teigland869d81d2006-01-17 08:47:12 +0000229 op->info.start = fl->fl_start;
230 op->info.end = fl->fl_end;
David Teigland2066b582007-12-06 09:35:25 -0600231 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;
David Teigland869d81d2006-01-17 08:47:12 +0000235
236 send_op(op);
237 wait_event(recv_wq, (op->done != 0));
238
239 spin_lock(&ops_lock);
240 if (!list_empty(&op->list)) {
David Teigland24022112008-03-14 15:09:15 -0500241 log_error(ls, "dlm_posix_unlock: op on list %llx",
242 (unsigned long long)number);
David Teigland869d81d2006-01-17 08:47:12 +0000243 list_del(&op->list);
244 }
245 spin_unlock(&ops_lock);
246
247 rv = op->info.rv;
248
Marc Eshel586759f2006-11-14 16:37:25 -0500249 if (rv == -ENOENT)
250 rv = 0;
251
David Teigland869d81d2006-01-17 08:47:12 +0000252 kfree(op);
David Teigland24022112008-03-14 15:09:15 -0500253out:
254 dlm_put_lockspace(ls);
David Teigland869d81d2006-01-17 08:47:12 +0000255 return rv;
256}
David Teigland24022112008-03-14 15:09:15 -0500257EXPORT_SYMBOL_GPL(dlm_posix_unlock);
David Teigland869d81d2006-01-17 08:47:12 +0000258
David Teigland24022112008-03-14 15:09:15 -0500259int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
260 struct file_lock *fl)
David Teigland869d81d2006-01-17 08:47:12 +0000261{
David Teigland24022112008-03-14 15:09:15 -0500262 struct dlm_ls *ls;
David Teigland869d81d2006-01-17 08:47:12 +0000263 struct plock_op *op;
264 int rv;
265
David Teigland24022112008-03-14 15:09:15 -0500266 ls = dlm_find_lockspace_local(lockspace);
267 if (!ls)
268 return -EINVAL;
David Teigland869d81d2006-01-17 08:47:12 +0000269
David Teigland573c24c2009-11-30 16:34:43 -0600270 op = kzalloc(sizeof(*op), GFP_NOFS);
David Teigland24022112008-03-14 15:09:15 -0500271 if (!op) {
272 rv = -ENOMEM;
273 goto out;
274 }
275
276 op->info.optype = DLM_PLOCK_OP_GET;
David Teigland3a2a9c92006-04-25 15:45:51 -0400277 op->info.pid = fl->fl_pid;
David Teigland869d81d2006-01-17 08:47:12 +0000278 op->info.ex = (fl->fl_type == F_WRLCK);
David Teigland24022112008-03-14 15:09:15 -0500279 op->info.fsid = ls->ls_global_id;
280 op->info.number = number;
David Teigland869d81d2006-01-17 08:47:12 +0000281 op->info.start = fl->fl_start;
282 op->info.end = fl->fl_end;
David Teigland2066b582007-12-06 09:35:25 -0600283 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;
Marc Eshel586759f2006-11-14 16:37:25 -0500287
David Teigland869d81d2006-01-17 08:47:12 +0000288 send_op(op);
289 wait_event(recv_wq, (op->done != 0));
290
291 spin_lock(&ops_lock);
292 if (!list_empty(&op->list)) {
David Teigland24022112008-03-14 15:09:15 -0500293 log_error(ls, "dlm_posix_get: op on list %llx",
294 (unsigned long long)number);
David Teigland869d81d2006-01-17 08:47:12 +0000295 list_del(&op->list);
296 }
297 spin_unlock(&ops_lock);
298
David Teiglanda7a2ff82007-06-08 17:01:40 -0500299 /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
300 -ENOENT if there are no locks on the file */
301
David Teigland869d81d2006-01-17 08:47:12 +0000302 rv = op->info.rv;
303
Marc Eshel586759f2006-11-14 16:37:25 -0500304 fl->fl_type = F_UNLCK;
305 if (rv == -ENOENT)
306 rv = 0;
David Teiglanda7a2ff82007-06-08 17:01:40 -0500307 else if (rv > 0) {
Jeff Layton20d5a392009-01-21 11:34:50 -0500308 locks_init_lock(fl);
David Teigland869d81d2006-01-17 08:47:12 +0000309 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
Jeff Layton20d5a392009-01-21 11:34:50 -0500310 fl->fl_flags = FL_POSIX;
David Teigland869d81d2006-01-17 08:47:12 +0000311 fl->fl_pid = op->info.pid;
312 fl->fl_start = op->info.start;
313 fl->fl_end = op->info.end;
David Teiglanda7a2ff82007-06-08 17:01:40 -0500314 rv = 0;
David Teigland869d81d2006-01-17 08:47:12 +0000315 }
316
317 kfree(op);
David Teigland24022112008-03-14 15:09:15 -0500318out:
319 dlm_put_lockspace(ls);
David Teigland869d81d2006-01-17 08:47:12 +0000320 return rv;
321}
David Teigland24022112008-03-14 15:09:15 -0500322EXPORT_SYMBOL_GPL(dlm_posix_get);
David Teigland869d81d2006-01-17 08:47:12 +0000323
324/* a read copies out one plock request from the send list */
325static ssize_t dev_read(struct file *file, char __user *u, size_t count,
326 loff_t *ppos)
327{
David Teigland24022112008-03-14 15:09:15 -0500328 struct dlm_plock_info info;
David Teigland869d81d2006-01-17 08:47:12 +0000329 struct plock_op *op = NULL;
330
331 if (count < sizeof(info))
332 return -EINVAL;
333
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));
339 }
340 spin_unlock(&ops_lock);
341
342 if (!op)
343 return -EAGAIN;
344
345 if (copy_to_user(u, &info, sizeof(info)))
346 return -EFAULT;
347 return sizeof(info);
348}
349
350/* a write copies in one plock result that should match a plock_op
351 on the recv list */
352static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
353 loff_t *ppos)
354{
David Teigland24022112008-03-14 15:09:15 -0500355 struct dlm_plock_info info;
David Teigland869d81d2006-01-17 08:47:12 +0000356 struct plock_op *op;
David Teiglandc78a87d2009-06-18 13:20:24 -0500357 int found = 0, do_callback = 0;
David Teigland869d81d2006-01-17 08:47:12 +0000358
359 if (count != sizeof(info))
360 return -EINVAL;
361
362 if (copy_from_user(&info, u, sizeof(info)))
363 return -EFAULT;
364
365 if (check_version(&info))
366 return -EINVAL;
367
368 spin_lock(&ops_lock);
369 list_for_each_entry(op, &recv_list, list) {
David Teiglandc78a87d2009-06-18 13:20:24 -0500370 if (op->info.fsid == info.fsid &&
371 op->info.number == info.number &&
David Teigland08eac932006-08-04 16:19:20 -0500372 op->info.owner == info.owner) {
David Teiglandc78a87d2009-06-18 13:20:24 -0500373 struct plock_xop *xop = (struct plock_xop *)op;
David Teigland869d81d2006-01-17 08:47:12 +0000374 list_del_init(&op->list);
David Teigland869d81d2006-01-17 08:47:12 +0000375 memcpy(&op->info, &info, sizeof(info));
David Teiglandc78a87d2009-06-18 13:20:24 -0500376 if (xop->callback)
377 do_callback = 1;
378 else
379 op->done = 1;
380 found = 1;
David Teigland869d81d2006-01-17 08:47:12 +0000381 break;
382 }
383 }
384 spin_unlock(&ops_lock);
385
Marc Eshel586759f2006-11-14 16:37:25 -0500386 if (found) {
David Teiglandc78a87d2009-06-18 13:20:24 -0500387 if (do_callback)
David Teigland817d10b2008-05-13 14:28:26 -0500388 dlm_plock_callback(op);
Marc Eshel586759f2006-11-14 16:37:25 -0500389 else
390 wake_up(&recv_wq);
391 } else
David Teigland24022112008-03-14 15:09:15 -0500392 log_print("dev_write no op %x %llx", info.fsid,
393 (unsigned long long)info.number);
David Teigland869d81d2006-01-17 08:47:12 +0000394 return count;
395}
396
397static unsigned int dev_poll(struct file *file, poll_table *wait)
398{
Denis Chengcee23c72007-07-25 17:53:58 +0800399 unsigned int mask = 0;
400
David Teigland869d81d2006-01-17 08:47:12 +0000401 poll_wait(file, &send_wq, wait);
402
403 spin_lock(&ops_lock);
Denis Chengcee23c72007-07-25 17:53:58 +0800404 if (!list_empty(&send_list))
405 mask = POLLIN | POLLRDNORM;
David Teigland869d81d2006-01-17 08:47:12 +0000406 spin_unlock(&ops_lock);
Denis Chengcee23c72007-07-25 17:53:58 +0800407
408 return mask;
David Teigland869d81d2006-01-17 08:47:12 +0000409}
410
Arjan van de Ven00977a52007-02-12 00:55:34 -0800411static const struct file_operations dev_fops = {
David Teigland869d81d2006-01-17 08:47:12 +0000412 .read = dev_read,
413 .write = dev_write,
414 .poll = dev_poll,
415 .owner = THIS_MODULE
416};
417
418static struct miscdevice plock_dev_misc = {
419 .minor = MISC_DYNAMIC_MINOR,
David Teigland24022112008-03-14 15:09:15 -0500420 .name = DLM_PLOCK_MISC_NAME,
David Teigland869d81d2006-01-17 08:47:12 +0000421 .fops = &dev_fops
422};
423
David Teigland24022112008-03-14 15:09:15 -0500424int dlm_plock_init(void)
David Teigland869d81d2006-01-17 08:47:12 +0000425{
426 int rv;
427
428 spin_lock_init(&ops_lock);
429 INIT_LIST_HEAD(&send_list);
430 INIT_LIST_HEAD(&recv_list);
431 init_waitqueue_head(&send_wq);
432 init_waitqueue_head(&recv_wq);
433
434 rv = misc_register(&plock_dev_misc);
435 if (rv)
David Teigland24022112008-03-14 15:09:15 -0500436 log_print("dlm_plock_init: misc_register failed %d", rv);
David Teigland869d81d2006-01-17 08:47:12 +0000437 return rv;
438}
439
David Teigland24022112008-03-14 15:09:15 -0500440void dlm_plock_exit(void)
David Teigland869d81d2006-01-17 08:47:12 +0000441{
442 if (misc_deregister(&plock_dev_misc) < 0)
David Teigland24022112008-03-14 15:09:15 -0500443 log_print("dlm_plock_exit: misc_deregister failed");
David Teigland869d81d2006-01-17 08:47:12 +0000444}
445