SYNC_FILE_RANGE_WRITE may and will block. Document that.
[linux-2.6/mini2440.git] / fs / dlm / user.c
blobf976f303c196284e2426167611325772c84d4cde
1 /*
2 * Copyright (C) 2006-2007 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 v.2.
7 */
9 #include <linux/miscdevice.h>
10 #include <linux/init.h>
11 #include <linux/wait.h>
12 #include <linux/module.h>
13 #include <linux/file.h>
14 #include <linux/fs.h>
15 #include <linux/poll.h>
16 #include <linux/signal.h>
17 #include <linux/spinlock.h>
18 #include <linux/smp_lock.h>
19 #include <linux/dlm.h>
20 #include <linux/dlm_device.h>
22 #include "dlm_internal.h"
23 #include "lockspace.h"
24 #include "lock.h"
25 #include "lvb_table.h"
26 #include "user.h"
28 static const char name_prefix[] = "dlm";
29 static const struct file_operations device_fops;
31 #ifdef CONFIG_COMPAT
33 struct dlm_lock_params32 {
34 __u8 mode;
35 __u8 namelen;
36 __u16 unused;
37 __u32 flags;
38 __u32 lkid;
39 __u32 parent;
40 __u64 xid;
41 __u64 timeout;
42 __u32 castparam;
43 __u32 castaddr;
44 __u32 bastparam;
45 __u32 bastaddr;
46 __u32 lksb;
47 char lvb[DLM_USER_LVB_LEN];
48 char name[0];
51 struct dlm_write_request32 {
52 __u32 version[3];
53 __u8 cmd;
54 __u8 is64bit;
55 __u8 unused[2];
57 union {
58 struct dlm_lock_params32 lock;
59 struct dlm_lspace_params lspace;
60 struct dlm_purge_params purge;
61 } i;
64 struct dlm_lksb32 {
65 __u32 sb_status;
66 __u32 sb_lkid;
67 __u8 sb_flags;
68 __u32 sb_lvbptr;
71 struct dlm_lock_result32 {
72 __u32 version[3];
73 __u32 length;
74 __u32 user_astaddr;
75 __u32 user_astparam;
76 __u32 user_lksb;
77 struct dlm_lksb32 lksb;
78 __u8 bast_mode;
79 __u8 unused[3];
80 /* Offsets may be zero if no data is present */
81 __u32 lvb_offset;
84 static void compat_input(struct dlm_write_request *kb,
85 struct dlm_write_request32 *kb32,
86 size_t count)
88 kb->version[0] = kb32->version[0];
89 kb->version[1] = kb32->version[1];
90 kb->version[2] = kb32->version[2];
92 kb->cmd = kb32->cmd;
93 kb->is64bit = kb32->is64bit;
94 if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
95 kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
96 kb->i.lspace.flags = kb32->i.lspace.flags;
97 kb->i.lspace.minor = kb32->i.lspace.minor;
98 memcpy(kb->i.lspace.name, kb32->i.lspace.name, count -
99 offsetof(struct dlm_write_request32, i.lspace.name));
100 } else if (kb->cmd == DLM_USER_PURGE) {
101 kb->i.purge.nodeid = kb32->i.purge.nodeid;
102 kb->i.purge.pid = kb32->i.purge.pid;
103 } else {
104 kb->i.lock.mode = kb32->i.lock.mode;
105 kb->i.lock.namelen = kb32->i.lock.namelen;
106 kb->i.lock.flags = kb32->i.lock.flags;
107 kb->i.lock.lkid = kb32->i.lock.lkid;
108 kb->i.lock.parent = kb32->i.lock.parent;
109 kb->i.lock.xid = kb32->i.lock.xid;
110 kb->i.lock.timeout = kb32->i.lock.timeout;
111 kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
112 kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
113 kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
114 kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
115 kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
116 memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
117 memcpy(kb->i.lock.name, kb32->i.lock.name, count -
118 offsetof(struct dlm_write_request32, i.lock.name));
122 static void compat_output(struct dlm_lock_result *res,
123 struct dlm_lock_result32 *res32)
125 res32->version[0] = res->version[0];
126 res32->version[1] = res->version[1];
127 res32->version[2] = res->version[2];
129 res32->user_astaddr = (__u32)(long)res->user_astaddr;
130 res32->user_astparam = (__u32)(long)res->user_astparam;
131 res32->user_lksb = (__u32)(long)res->user_lksb;
132 res32->bast_mode = res->bast_mode;
134 res32->lvb_offset = res->lvb_offset;
135 res32->length = res->length;
137 res32->lksb.sb_status = res->lksb.sb_status;
138 res32->lksb.sb_flags = res->lksb.sb_flags;
139 res32->lksb.sb_lkid = res->lksb.sb_lkid;
140 res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
142 #endif
144 /* Figure out if this lock is at the end of its life and no longer
145 available for the application to use. The lkb still exists until
146 the final ast is read. A lock becomes EOL in three situations:
147 1. a noqueue request fails with EAGAIN
148 2. an unlock completes with EUNLOCK
149 3. a cancel of a waiting request completes with ECANCEL/EDEADLK
150 An EOL lock needs to be removed from the process's list of locks.
151 And we can't allow any new operation on an EOL lock. This is
152 not related to the lifetime of the lkb struct which is managed
153 entirely by refcount. */
155 static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
157 switch (sb_status) {
158 case -DLM_EUNLOCK:
159 return 1;
160 case -DLM_ECANCEL:
161 case -ETIMEDOUT:
162 case -EDEADLK:
163 if (lkb->lkb_grmode == DLM_LOCK_IV)
164 return 1;
165 break;
166 case -EAGAIN:
167 if (type == AST_COMP && lkb->lkb_grmode == DLM_LOCK_IV)
168 return 1;
169 break;
171 return 0;
174 /* we could possibly check if the cancel of an orphan has resulted in the lkb
175 being removed and then remove that lkb from the orphans list and free it */
177 void dlm_user_add_ast(struct dlm_lkb *lkb, int type)
179 struct dlm_ls *ls;
180 struct dlm_user_args *ua;
181 struct dlm_user_proc *proc;
182 int eol = 0, ast_type;
184 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
185 return;
187 ls = lkb->lkb_resource->res_ls;
188 mutex_lock(&ls->ls_clear_proc_locks);
190 /* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
191 can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
192 lkb->ua so we can't try to use it. This second check is necessary
193 for cases where a completion ast is received for an operation that
194 began before clear_proc_locks did its cancel/unlock. */
196 if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
197 goto out;
199 DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
200 ua = lkb->lkb_ua;
201 proc = ua->proc;
203 if (type == AST_BAST && ua->bastaddr == NULL)
204 goto out;
206 spin_lock(&proc->asts_spin);
208 ast_type = lkb->lkb_ast_type;
209 lkb->lkb_ast_type |= type;
211 if (!ast_type) {
212 kref_get(&lkb->lkb_ref);
213 list_add_tail(&lkb->lkb_astqueue, &proc->asts);
214 wake_up_interruptible(&proc->wait);
216 if (type == AST_COMP && (ast_type & AST_COMP))
217 log_debug(ls, "ast overlap %x status %x %x",
218 lkb->lkb_id, ua->lksb.sb_status, lkb->lkb_flags);
220 eol = lkb_is_endoflife(lkb, ua->lksb.sb_status, type);
221 if (eol) {
222 lkb->lkb_ast_type &= ~AST_BAST;
223 lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
226 /* We want to copy the lvb to userspace when the completion
227 ast is read if the status is 0, the lock has an lvb and
228 lvb_ops says we should. We could probably have set_lvb_lock()
229 set update_user_lvb instead and not need old_mode */
231 if ((lkb->lkb_ast_type & AST_COMP) &&
232 (lkb->lkb_lksb->sb_status == 0) &&
233 lkb->lkb_lksb->sb_lvbptr &&
234 dlm_lvb_operations[ua->old_mode + 1][lkb->lkb_grmode + 1])
235 ua->update_user_lvb = 1;
236 else
237 ua->update_user_lvb = 0;
239 spin_unlock(&proc->asts_spin);
241 if (eol) {
242 spin_lock(&proc->locks_spin);
243 if (!list_empty(&lkb->lkb_ownqueue)) {
244 list_del_init(&lkb->lkb_ownqueue);
245 dlm_put_lkb(lkb);
247 spin_unlock(&proc->locks_spin);
249 out:
250 mutex_unlock(&ls->ls_clear_proc_locks);
253 static int device_user_lock(struct dlm_user_proc *proc,
254 struct dlm_lock_params *params)
256 struct dlm_ls *ls;
257 struct dlm_user_args *ua;
258 int error = -ENOMEM;
260 ls = dlm_find_lockspace_local(proc->lockspace);
261 if (!ls)
262 return -ENOENT;
264 if (!params->castaddr || !params->lksb) {
265 error = -EINVAL;
266 goto out;
269 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
270 if (!ua)
271 goto out;
272 ua->proc = proc;
273 ua->user_lksb = params->lksb;
274 ua->castparam = params->castparam;
275 ua->castaddr = params->castaddr;
276 ua->bastparam = params->bastparam;
277 ua->bastaddr = params->bastaddr;
278 ua->xid = params->xid;
280 if (params->flags & DLM_LKF_CONVERT)
281 error = dlm_user_convert(ls, ua,
282 params->mode, params->flags,
283 params->lkid, params->lvb,
284 (unsigned long) params->timeout);
285 else {
286 error = dlm_user_request(ls, ua,
287 params->mode, params->flags,
288 params->name, params->namelen,
289 (unsigned long) params->timeout);
290 if (!error)
291 error = ua->lksb.sb_lkid;
293 out:
294 dlm_put_lockspace(ls);
295 return error;
298 static int device_user_unlock(struct dlm_user_proc *proc,
299 struct dlm_lock_params *params)
301 struct dlm_ls *ls;
302 struct dlm_user_args *ua;
303 int error = -ENOMEM;
305 ls = dlm_find_lockspace_local(proc->lockspace);
306 if (!ls)
307 return -ENOENT;
309 ua = kzalloc(sizeof(struct dlm_user_args), GFP_KERNEL);
310 if (!ua)
311 goto out;
312 ua->proc = proc;
313 ua->user_lksb = params->lksb;
314 ua->castparam = params->castparam;
315 ua->castaddr = params->castaddr;
317 if (params->flags & DLM_LKF_CANCEL)
318 error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
319 else
320 error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
321 params->lvb);
322 out:
323 dlm_put_lockspace(ls);
324 return error;
327 static int device_user_deadlock(struct dlm_user_proc *proc,
328 struct dlm_lock_params *params)
330 struct dlm_ls *ls;
331 int error;
333 ls = dlm_find_lockspace_local(proc->lockspace);
334 if (!ls)
335 return -ENOENT;
337 error = dlm_user_deadlock(ls, params->flags, params->lkid);
339 dlm_put_lockspace(ls);
340 return error;
343 static int create_misc_device(struct dlm_ls *ls, char *name)
345 int error, len;
347 error = -ENOMEM;
348 len = strlen(name) + strlen(name_prefix) + 2;
349 ls->ls_device.name = kzalloc(len, GFP_KERNEL);
350 if (!ls->ls_device.name)
351 goto fail;
353 snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
354 name);
355 ls->ls_device.fops = &device_fops;
356 ls->ls_device.minor = MISC_DYNAMIC_MINOR;
358 error = misc_register(&ls->ls_device);
359 if (error) {
360 kfree(ls->ls_device.name);
362 fail:
363 return error;
366 static int device_user_purge(struct dlm_user_proc *proc,
367 struct dlm_purge_params *params)
369 struct dlm_ls *ls;
370 int error;
372 ls = dlm_find_lockspace_local(proc->lockspace);
373 if (!ls)
374 return -ENOENT;
376 error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
378 dlm_put_lockspace(ls);
379 return error;
382 static int device_create_lockspace(struct dlm_lspace_params *params)
384 dlm_lockspace_t *lockspace;
385 struct dlm_ls *ls;
386 int error;
388 if (!capable(CAP_SYS_ADMIN))
389 return -EPERM;
391 error = dlm_new_lockspace(params->name, strlen(params->name),
392 &lockspace, params->flags, DLM_USER_LVB_LEN);
393 if (error)
394 return error;
396 ls = dlm_find_lockspace_local(lockspace);
397 if (!ls)
398 return -ENOENT;
400 error = create_misc_device(ls, params->name);
401 dlm_put_lockspace(ls);
403 if (error)
404 dlm_release_lockspace(lockspace, 0);
405 else
406 error = ls->ls_device.minor;
408 return error;
411 static int device_remove_lockspace(struct dlm_lspace_params *params)
413 dlm_lockspace_t *lockspace;
414 struct dlm_ls *ls;
415 int error, force = 0;
417 if (!capable(CAP_SYS_ADMIN))
418 return -EPERM;
420 ls = dlm_find_lockspace_device(params->minor);
421 if (!ls)
422 return -ENOENT;
424 /* Deregister the misc device first, so we don't have
425 * a device that's not attached to a lockspace. If
426 * dlm_release_lockspace fails then we can recreate it
428 error = misc_deregister(&ls->ls_device);
429 if (error) {
430 dlm_put_lockspace(ls);
431 goto out;
433 kfree(ls->ls_device.name);
435 if (params->flags & DLM_USER_LSFLG_FORCEFREE)
436 force = 2;
438 lockspace = ls->ls_local_handle;
440 /* dlm_release_lockspace waits for references to go to zero,
441 so all processes will need to close their device for the ls
442 before the release will procede */
444 dlm_put_lockspace(ls);
445 error = dlm_release_lockspace(lockspace, force);
446 if (error)
447 create_misc_device(ls, ls->ls_name);
448 out:
449 return error;
452 /* Check the user's version matches ours */
453 static int check_version(struct dlm_write_request *req)
455 if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
456 (req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
457 req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
459 printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
460 "user (%d.%d.%d) kernel (%d.%d.%d)\n",
461 current->comm,
462 task_pid_nr(current),
463 req->version[0],
464 req->version[1],
465 req->version[2],
466 DLM_DEVICE_VERSION_MAJOR,
467 DLM_DEVICE_VERSION_MINOR,
468 DLM_DEVICE_VERSION_PATCH);
469 return -EINVAL;
471 return 0;
475 * device_write
477 * device_user_lock
478 * dlm_user_request -> request_lock
479 * dlm_user_convert -> convert_lock
481 * device_user_unlock
482 * dlm_user_unlock -> unlock_lock
483 * dlm_user_cancel -> cancel_lock
485 * device_create_lockspace
486 * dlm_new_lockspace
488 * device_remove_lockspace
489 * dlm_release_lockspace
492 /* a write to a lockspace device is a lock or unlock request, a write
493 to the control device is to create/remove a lockspace */
495 static ssize_t device_write(struct file *file, const char __user *buf,
496 size_t count, loff_t *ppos)
498 struct dlm_user_proc *proc = file->private_data;
499 struct dlm_write_request *kbuf;
500 sigset_t tmpsig, allsigs;
501 int error;
503 #ifdef CONFIG_COMPAT
504 if (count < sizeof(struct dlm_write_request32))
505 #else
506 if (count < sizeof(struct dlm_write_request))
507 #endif
508 return -EINVAL;
510 kbuf = kzalloc(count + 1, GFP_KERNEL);
511 if (!kbuf)
512 return -ENOMEM;
514 if (copy_from_user(kbuf, buf, count)) {
515 error = -EFAULT;
516 goto out_free;
519 if (check_version(kbuf)) {
520 error = -EBADE;
521 goto out_free;
524 #ifdef CONFIG_COMPAT
525 if (!kbuf->is64bit) {
526 struct dlm_write_request32 *k32buf;
527 k32buf = (struct dlm_write_request32 *)kbuf;
528 kbuf = kmalloc(count + 1 + (sizeof(struct dlm_write_request) -
529 sizeof(struct dlm_write_request32)), GFP_KERNEL);
530 if (!kbuf)
531 return -ENOMEM;
533 if (proc)
534 set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
535 compat_input(kbuf, k32buf, count + 1);
536 kfree(k32buf);
538 #endif
540 /* do we really need this? can a write happen after a close? */
541 if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
542 test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
543 return -EINVAL;
545 sigfillset(&allsigs);
546 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
548 error = -EINVAL;
550 switch (kbuf->cmd)
552 case DLM_USER_LOCK:
553 if (!proc) {
554 log_print("no locking on control device");
555 goto out_sig;
557 error = device_user_lock(proc, &kbuf->i.lock);
558 break;
560 case DLM_USER_UNLOCK:
561 if (!proc) {
562 log_print("no locking on control device");
563 goto out_sig;
565 error = device_user_unlock(proc, &kbuf->i.lock);
566 break;
568 case DLM_USER_DEADLOCK:
569 if (!proc) {
570 log_print("no locking on control device");
571 goto out_sig;
573 error = device_user_deadlock(proc, &kbuf->i.lock);
574 break;
576 case DLM_USER_CREATE_LOCKSPACE:
577 if (proc) {
578 log_print("create/remove only on control device");
579 goto out_sig;
581 error = device_create_lockspace(&kbuf->i.lspace);
582 break;
584 case DLM_USER_REMOVE_LOCKSPACE:
585 if (proc) {
586 log_print("create/remove only on control device");
587 goto out_sig;
589 error = device_remove_lockspace(&kbuf->i.lspace);
590 break;
592 case DLM_USER_PURGE:
593 if (!proc) {
594 log_print("no locking on control device");
595 goto out_sig;
597 error = device_user_purge(proc, &kbuf->i.purge);
598 break;
600 default:
601 log_print("Unknown command passed to DLM device : %d\n",
602 kbuf->cmd);
605 out_sig:
606 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
607 recalc_sigpending();
608 out_free:
609 kfree(kbuf);
610 return error;
613 /* Every process that opens the lockspace device has its own "proc" structure
614 hanging off the open file that's used to keep track of locks owned by the
615 process and asts that need to be delivered to the process. */
617 static int device_open(struct inode *inode, struct file *file)
619 struct dlm_user_proc *proc;
620 struct dlm_ls *ls;
622 lock_kernel();
623 ls = dlm_find_lockspace_device(iminor(inode));
624 if (!ls) {
625 unlock_kernel();
626 return -ENOENT;
629 proc = kzalloc(sizeof(struct dlm_user_proc), GFP_KERNEL);
630 if (!proc) {
631 dlm_put_lockspace(ls);
632 unlock_kernel();
633 return -ENOMEM;
636 proc->lockspace = ls->ls_local_handle;
637 INIT_LIST_HEAD(&proc->asts);
638 INIT_LIST_HEAD(&proc->locks);
639 INIT_LIST_HEAD(&proc->unlocking);
640 spin_lock_init(&proc->asts_spin);
641 spin_lock_init(&proc->locks_spin);
642 init_waitqueue_head(&proc->wait);
643 file->private_data = proc;
644 unlock_kernel();
646 return 0;
649 static int device_close(struct inode *inode, struct file *file)
651 struct dlm_user_proc *proc = file->private_data;
652 struct dlm_ls *ls;
653 sigset_t tmpsig, allsigs;
655 ls = dlm_find_lockspace_local(proc->lockspace);
656 if (!ls)
657 return -ENOENT;
659 sigfillset(&allsigs);
660 sigprocmask(SIG_BLOCK, &allsigs, &tmpsig);
662 set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
664 dlm_clear_proc_locks(ls, proc);
666 /* at this point no more lkb's should exist for this lockspace,
667 so there's no chance of dlm_user_add_ast() being called and
668 looking for lkb->ua->proc */
670 kfree(proc);
671 file->private_data = NULL;
673 dlm_put_lockspace(ls);
674 dlm_put_lockspace(ls); /* for the find in device_open() */
676 /* FIXME: AUTOFREE: if this ls is no longer used do
677 device_remove_lockspace() */
679 sigprocmask(SIG_SETMASK, &tmpsig, NULL);
680 recalc_sigpending();
682 return 0;
685 static int copy_result_to_user(struct dlm_user_args *ua, int compat, int type,
686 int bmode, char __user *buf, size_t count)
688 #ifdef CONFIG_COMPAT
689 struct dlm_lock_result32 result32;
690 #endif
691 struct dlm_lock_result result;
692 void *resultptr;
693 int error=0;
694 int len;
695 int struct_len;
697 memset(&result, 0, sizeof(struct dlm_lock_result));
698 result.version[0] = DLM_DEVICE_VERSION_MAJOR;
699 result.version[1] = DLM_DEVICE_VERSION_MINOR;
700 result.version[2] = DLM_DEVICE_VERSION_PATCH;
701 memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
702 result.user_lksb = ua->user_lksb;
704 /* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
705 in a conversion unless the conversion is successful. See code
706 in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
707 notes that a new blocking AST address and parameter are set even if
708 the conversion fails, so maybe we should just do that. */
710 if (type == AST_BAST) {
711 result.user_astaddr = ua->bastaddr;
712 result.user_astparam = ua->bastparam;
713 result.bast_mode = bmode;
714 } else {
715 result.user_astaddr = ua->castaddr;
716 result.user_astparam = ua->castparam;
719 #ifdef CONFIG_COMPAT
720 if (compat)
721 len = sizeof(struct dlm_lock_result32);
722 else
723 #endif
724 len = sizeof(struct dlm_lock_result);
725 struct_len = len;
727 /* copy lvb to userspace if there is one, it's been updated, and
728 the user buffer has space for it */
730 if (ua->update_user_lvb && ua->lksb.sb_lvbptr &&
731 count >= len + DLM_USER_LVB_LEN) {
732 if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
733 DLM_USER_LVB_LEN)) {
734 error = -EFAULT;
735 goto out;
738 result.lvb_offset = len;
739 len += DLM_USER_LVB_LEN;
742 result.length = len;
743 resultptr = &result;
744 #ifdef CONFIG_COMPAT
745 if (compat) {
746 compat_output(&result, &result32);
747 resultptr = &result32;
749 #endif
751 if (copy_to_user(buf, resultptr, struct_len))
752 error = -EFAULT;
753 else
754 error = len;
755 out:
756 return error;
759 static int copy_version_to_user(char __user *buf, size_t count)
761 struct dlm_device_version ver;
763 memset(&ver, 0, sizeof(struct dlm_device_version));
764 ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
765 ver.version[1] = DLM_DEVICE_VERSION_MINOR;
766 ver.version[2] = DLM_DEVICE_VERSION_PATCH;
768 if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
769 return -EFAULT;
770 return sizeof(struct dlm_device_version);
773 /* a read returns a single ast described in a struct dlm_lock_result */
775 static ssize_t device_read(struct file *file, char __user *buf, size_t count,
776 loff_t *ppos)
778 struct dlm_user_proc *proc = file->private_data;
779 struct dlm_lkb *lkb;
780 DECLARE_WAITQUEUE(wait, current);
781 int error, type=0, bmode=0, removed = 0;
783 if (count == sizeof(struct dlm_device_version)) {
784 error = copy_version_to_user(buf, count);
785 return error;
788 if (!proc) {
789 log_print("non-version read from control device %zu", count);
790 return -EINVAL;
793 #ifdef CONFIG_COMPAT
794 if (count < sizeof(struct dlm_lock_result32))
795 #else
796 if (count < sizeof(struct dlm_lock_result))
797 #endif
798 return -EINVAL;
800 /* do we really need this? can a read happen after a close? */
801 if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
802 return -EINVAL;
804 spin_lock(&proc->asts_spin);
805 if (list_empty(&proc->asts)) {
806 if (file->f_flags & O_NONBLOCK) {
807 spin_unlock(&proc->asts_spin);
808 return -EAGAIN;
811 add_wait_queue(&proc->wait, &wait);
813 repeat:
814 set_current_state(TASK_INTERRUPTIBLE);
815 if (list_empty(&proc->asts) && !signal_pending(current)) {
816 spin_unlock(&proc->asts_spin);
817 schedule();
818 spin_lock(&proc->asts_spin);
819 goto repeat;
821 set_current_state(TASK_RUNNING);
822 remove_wait_queue(&proc->wait, &wait);
824 if (signal_pending(current)) {
825 spin_unlock(&proc->asts_spin);
826 return -ERESTARTSYS;
830 /* there may be both completion and blocking asts to return for
831 the lkb, don't remove lkb from asts list unless no asts remain */
833 lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_astqueue);
835 if (lkb->lkb_ast_type & AST_COMP) {
836 lkb->lkb_ast_type &= ~AST_COMP;
837 type = AST_COMP;
838 } else if (lkb->lkb_ast_type & AST_BAST) {
839 lkb->lkb_ast_type &= ~AST_BAST;
840 type = AST_BAST;
841 bmode = lkb->lkb_bastmode;
844 if (!lkb->lkb_ast_type) {
845 list_del(&lkb->lkb_astqueue);
846 removed = 1;
848 spin_unlock(&proc->asts_spin);
850 error = copy_result_to_user(lkb->lkb_ua,
851 test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
852 type, bmode, buf, count);
854 /* removes reference for the proc->asts lists added by
855 dlm_user_add_ast() and may result in the lkb being freed */
856 if (removed)
857 dlm_put_lkb(lkb);
859 return error;
862 static unsigned int device_poll(struct file *file, poll_table *wait)
864 struct dlm_user_proc *proc = file->private_data;
866 poll_wait(file, &proc->wait, wait);
868 spin_lock(&proc->asts_spin);
869 if (!list_empty(&proc->asts)) {
870 spin_unlock(&proc->asts_spin);
871 return POLLIN | POLLRDNORM;
873 spin_unlock(&proc->asts_spin);
874 return 0;
877 static int ctl_device_open(struct inode *inode, struct file *file)
879 cycle_kernel_lock();
880 file->private_data = NULL;
881 return 0;
884 static int ctl_device_close(struct inode *inode, struct file *file)
886 return 0;
889 static const struct file_operations device_fops = {
890 .open = device_open,
891 .release = device_close,
892 .read = device_read,
893 .write = device_write,
894 .poll = device_poll,
895 .owner = THIS_MODULE,
898 static const struct file_operations ctl_device_fops = {
899 .open = ctl_device_open,
900 .release = ctl_device_close,
901 .read = device_read,
902 .write = device_write,
903 .owner = THIS_MODULE,
906 static struct miscdevice ctl_device = {
907 .name = "dlm-control",
908 .fops = &ctl_device_fops,
909 .minor = MISC_DYNAMIC_MINOR,
912 int __init dlm_user_init(void)
914 int error;
916 error = misc_register(&ctl_device);
917 if (error)
918 log_print("misc_register failed for control device");
920 return error;
923 void dlm_user_exit(void)
925 misc_deregister(&ctl_device);