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.
10 #include <linux/miscdevice.h>
11 #include <linux/poll.h>
12 #include <linux/dlm.h>
13 #include <linux/dlm_plock.h>
15 #include "dlm_internal.h"
16 #include "lockspace.h"
18 static spinlock_t ops_lock;
19 static struct list_head send_list;
20 static struct list_head recv_list;
21 static wait_queue_head_t send_wq;
22 static wait_queue_head_t recv_wq;
25 struct list_head list;
27 struct dlm_plock_info info;
39 static inline void set_version(struct dlm_plock_info *info)
41 info->version[0] = DLM_PLOCK_VERSION_MAJOR;
42 info->version[1] = DLM_PLOCK_VERSION_MINOR;
43 info->version[2] = DLM_PLOCK_VERSION_PATCH;
46 static int check_version(struct dlm_plock_info *info)
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,
63 static void send_op(struct plock_op *op)
65 set_version(&op->info);
66 INIT_LIST_HEAD(&op->list);
68 list_add_tail(&op->list, &send_list);
69 spin_unlock(&ops_lock);
73 int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
74 int cmd, struct file_lock *fl)
78 struct plock_xop *xop;
81 ls = dlm_find_lockspace_local(lockspace);
85 xop = kzalloc(sizeof(*xop), GFP_KERNEL);
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);
110 op->info.owner = (__u64)(long) fl->fl_owner;
111 xop->callback = NULL;
116 if (xop->callback == NULL)
117 wait_event(recv_wq, (op->done != 0));
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);
129 spin_unlock(&ops_lock);
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);
141 dlm_put_lockspace(ls);
144 EXPORT_SYMBOL_GPL(dlm_posix_lock);
146 /* Returns failure iff a succesful lock operation should be canceled */
147 static int dlm_plock_callback(struct plock_op *op)
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;
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);
162 spin_unlock(&ops_lock);
164 /* check if the following 2 are still valid or make a copy */
168 notify = xop->callback;
171 notify(flc, NULL, op->info.rv);
175 /* got fs lock; bookkeep locally as well: */
176 flc->fl_flags &= ~FL_SLEEP;
177 if (posix_lock_file(file, flc, NULL)) {
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.
186 log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p",
187 (unsigned long long)op->info.number, file, fl);
190 rv = notify(flc, NULL, 0);
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");
203 int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file,
204 struct file_lock *fl)
210 ls = dlm_find_lockspace_local(lockspace);
214 op = kzalloc(sizeof(*op), GFP_KERNEL);
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);
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;
233 op->info.owner = (__u64)(long) fl->fl_owner;
236 wait_event(recv_wq, (op->done != 0));
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);
244 spin_unlock(&ops_lock);
253 dlm_put_lockspace(ls);
256 EXPORT_SYMBOL_GPL(dlm_posix_unlock);
258 int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file,
259 struct file_lock *fl)
265 ls = dlm_find_lockspace_local(lockspace);
269 op = kzalloc(sizeof(*op), GFP_KERNEL);
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;
285 op->info.owner = (__u64)(long) fl->fl_owner;
288 wait_event(recv_wq, (op->done != 0));
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);
296 spin_unlock(&ops_lock);
298 /* info.rv from userspace is 1 for conflict, 0 for no-conflict,
299 -ENOENT if there are no locks on the file */
303 fl->fl_type = F_UNLCK;
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;
316 dlm_put_lockspace(ls);
319 EXPORT_SYMBOL_GPL(dlm_posix_get);
321 /* a read copies out one plock request from the send list */
322 static ssize_t dev_read(struct file *file, char __user *u, size_t count,
325 struct dlm_plock_info info;
326 struct plock_op *op = NULL;
328 if (count < sizeof(info))
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));
337 spin_unlock(&ops_lock);
342 if (copy_to_user(u, &info, sizeof(info)))
347 /* a write copies in one plock result that should match a plock_op
349 static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
352 struct dlm_plock_info info;
356 if (count != sizeof(info))
359 if (copy_from_user(&info, u, sizeof(info)))
362 if (check_version(&info))
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);
372 memcpy(&op->info, &info, sizeof(info));
376 spin_unlock(&ops_lock);
379 struct plock_xop *xop;
380 xop = (struct plock_xop *)op;
382 count = dlm_plock_callback(op);
386 log_print("dev_write no op %x %llx", info.fsid,
387 (unsigned long long)info.number);
391 static unsigned int dev_poll(struct file *file, poll_table *wait)
393 unsigned int mask = 0;
395 poll_wait(file, &send_wq, wait);
397 spin_lock(&ops_lock);
398 if (!list_empty(&send_list))
399 mask = POLLIN | POLLRDNORM;
400 spin_unlock(&ops_lock);
405 static const struct file_operations dev_fops = {
412 static struct miscdevice plock_dev_misc = {
413 .minor = MISC_DYNAMIC_MINOR,
414 .name = DLM_PLOCK_MISC_NAME,
418 int dlm_plock_init(void)
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);
428 rv = misc_register(&plock_dev_misc);
430 log_print("dlm_plock_init: misc_register failed %d", rv);
434 void dlm_plock_exit(void)
436 if (misc_deregister(&plock_dev_misc) < 0)
437 log_print("dlm_plock_exit: misc_deregister failed");