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1/*
2 * GPL HEADER START
3 *
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
19 *
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
22 * have any questions.
23 *
24 * GPL HEADER END
25 */
26/*
27 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
29 *
30 * Copyright (c) 2010, 2012, Intel Corporation.
31 */
32/*
33 * This file is part of Lustre, http://www.lustre.org/
34 * Lustre is a trademark of Sun Microsystems, Inc.
35 */
36/**
37 * This file contains Asynchronous System Trap (AST) handlers and related
38 * LDLM request-processing routines.
39 *
40 * An AST is a callback issued on a lock when its state is changed. There are
41 * several different types of ASTs (callbacks) registered for each lock:
42 *
43 * - completion AST: when a lock is enqueued by some process, but cannot be
44 *   granted immediately due to other conflicting locks on the same resource,
45 *   the completion AST is sent to notify the caller when the lock is
46 *   eventually granted
47 *
48 * - blocking AST: when a lock is granted to some process, if another process
49 *   enqueues a conflicting (blocking) lock on a resource, a blocking AST is
50 *   sent to notify the holder(s) of the lock(s) of the conflicting lock
51 *   request. The lock holder(s) must release their lock(s) on that resource in
52 *   a timely manner or be evicted by the server.
53 *
54 * - glimpse AST: this is used when a process wants information about a lock
55 *   (i.e. the lock value block (LVB)) but does not necessarily require holding
56 *   the lock. If the resource is locked, the lock holder(s) are sent glimpse
57 *   ASTs and the LVB is returned to the caller, and lock holder(s) may CANCEL
58 *   their lock(s) if they are idle. If the resource is not locked, the server
59 *   may grant the lock.
60 */
61
62#define DEBUG_SUBSYSTEM S_LDLM
63
64#include "../include/lustre_dlm.h"
65#include "../include/obd_class.h"
66#include "../include/obd.h"
67
68#include "ldlm_internal.h"
69
70int ldlm_enqueue_min = OBD_TIMEOUT_DEFAULT;
71module_param(ldlm_enqueue_min, int, 0644);
72MODULE_PARM_DESC(ldlm_enqueue_min, "lock enqueue timeout minimum");
73
74/* in client side, whether the cached locks will be canceled before replay */
75unsigned int ldlm_cancel_unused_locks_before_replay = 1;
76
77static void interrupted_completion_wait(void *data)
78{
79}
80
81struct lock_wait_data {
82	struct ldlm_lock *lwd_lock;
83	__u32	     lwd_conn_cnt;
84};
85
86struct ldlm_async_args {
87	struct lustre_handle lock_handle;
88};
89
90int ldlm_expired_completion_wait(void *data)
91{
92	struct lock_wait_data *lwd = data;
93	struct ldlm_lock *lock = lwd->lwd_lock;
94	struct obd_import *imp;
95	struct obd_device *obd;
96
97	if (lock->l_conn_export == NULL) {
98		static unsigned long next_dump = 0, last_dump = 0;
99
100		LCONSOLE_WARN("lock timed out (enqueued at "CFS_TIME_T", "
101			      CFS_DURATION_T"s ago)\n",
102			      lock->l_last_activity,
103			      cfs_time_sub(get_seconds(),
104					   lock->l_last_activity));
105		LDLM_DEBUG(lock, "lock timed out (enqueued at "CFS_TIME_T", "
106			   CFS_DURATION_T"s ago); not entering recovery in "
107			   "server code, just going back to sleep",
108			   lock->l_last_activity,
109			   cfs_time_sub(get_seconds(),
110					lock->l_last_activity));
111		if (cfs_time_after(cfs_time_current(), next_dump)) {
112			last_dump = next_dump;
113			next_dump = cfs_time_shift(300);
114			ldlm_namespace_dump(D_DLMTRACE,
115					    ldlm_lock_to_ns(lock));
116			if (last_dump == 0)
117				libcfs_debug_dumplog();
118		}
119		return 0;
120	}
121
122	obd = lock->l_conn_export->exp_obd;
123	imp = obd->u.cli.cl_import;
124	ptlrpc_fail_import(imp, lwd->lwd_conn_cnt);
125	LDLM_ERROR(lock, "lock timed out (enqueued at "CFS_TIME_T", "
126		  CFS_DURATION_T"s ago), entering recovery for %s@%s",
127		  lock->l_last_activity,
128		  cfs_time_sub(get_seconds(), lock->l_last_activity),
129		  obd2cli_tgt(obd), imp->imp_connection->c_remote_uuid.uuid);
130
131	return 0;
132}
133EXPORT_SYMBOL(ldlm_expired_completion_wait);
134
135/* We use the same basis for both server side and client side functions
136   from a single node. */
137int ldlm_get_enq_timeout(struct ldlm_lock *lock)
138{
139	int timeout = at_get(ldlm_lock_to_ns_at(lock));
140	if (AT_OFF)
141		return obd_timeout / 2;
142	/* Since these are non-updating timeouts, we should be conservative.
143	   It would be nice to have some kind of "early reply" mechanism for
144	   lock callbacks too... */
145	timeout = min_t(int, at_max, timeout + (timeout >> 1)); /* 150% */
146	return max(timeout, ldlm_enqueue_min);
147}
148EXPORT_SYMBOL(ldlm_get_enq_timeout);
149
150/**
151 * Helper function for ldlm_completion_ast(), updating timings when lock is
152 * actually granted.
153 */
154static int ldlm_completion_tail(struct ldlm_lock *lock)
155{
156	long delay;
157	int  result;
158
159	if (lock->l_flags & (LDLM_FL_DESTROYED | LDLM_FL_FAILED)) {
160		LDLM_DEBUG(lock, "client-side enqueue: destroyed");
161		result = -EIO;
162	} else {
163		delay = cfs_time_sub(get_seconds(),
164				     lock->l_last_activity);
165		LDLM_DEBUG(lock, "client-side enqueue: granted after "
166			   CFS_DURATION_T"s", delay);
167
168		/* Update our time estimate */
169		at_measured(ldlm_lock_to_ns_at(lock),
170			    delay);
171		result = 0;
172	}
173	return result;
174}
175
176/**
177 * Implementation of ->l_completion_ast() for a client, that doesn't wait
178 * until lock is granted. Suitable for locks enqueued through ptlrpcd, of
179 * other threads that cannot block for long.
180 */
181int ldlm_completion_ast_async(struct ldlm_lock *lock, __u64 flags, void *data)
182{
183	if (flags == LDLM_FL_WAIT_NOREPROC) {
184		LDLM_DEBUG(lock, "client-side enqueue waiting on pending lock");
185		return 0;
186	}
187
188	if (!(flags & (LDLM_FL_BLOCK_WAIT | LDLM_FL_BLOCK_GRANTED |
189		       LDLM_FL_BLOCK_CONV))) {
190		wake_up(&lock->l_waitq);
191		return ldlm_completion_tail(lock);
192	}
193
194	LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
195		   "going forward");
196	ldlm_reprocess_all(lock->l_resource);
197	return 0;
198}
199EXPORT_SYMBOL(ldlm_completion_ast_async);
200
201/**
202 * Generic LDLM "completion" AST. This is called in several cases:
203 *
204 *     - when a reply to an ENQUEUE RPC is received from the server
205 *       (ldlm_cli_enqueue_fini()). Lock might be granted or not granted at
206 *       this point (determined by flags);
207 *
208 *     - when LDLM_CP_CALLBACK RPC comes to client to notify it that lock has
209 *       been granted;
210 *
211 *     - when ldlm_lock_match(LDLM_FL_LVB_READY) is about to wait until lock
212 *       gets correct lvb;
213 *
214 *     - to force all locks when resource is destroyed (cleanup_resource());
215 *
216 *     - during lock conversion (not used currently).
217 *
218 * If lock is not granted in the first case, this function waits until second
219 * or penultimate cases happen in some other thread.
220 *
221 */
222int ldlm_completion_ast(struct ldlm_lock *lock, __u64 flags, void *data)
223{
224	/* XXX ALLOCATE - 160 bytes */
225	struct lock_wait_data lwd;
226	struct obd_device *obd;
227	struct obd_import *imp = NULL;
228	struct l_wait_info lwi;
229	__u32 timeout;
230	int rc = 0;
231
232	if (flags == LDLM_FL_WAIT_NOREPROC) {
233		LDLM_DEBUG(lock, "client-side enqueue waiting on pending lock");
234		goto noreproc;
235	}
236
237	if (!(flags & (LDLM_FL_BLOCK_WAIT | LDLM_FL_BLOCK_GRANTED |
238		       LDLM_FL_BLOCK_CONV))) {
239		wake_up(&lock->l_waitq);
240		return 0;
241	}
242
243	LDLM_DEBUG(lock, "client-side enqueue returned a blocked lock, "
244		   "sleeping");
245
246noreproc:
247
248	obd = class_exp2obd(lock->l_conn_export);
249
250	/* if this is a local lock, then there is no import */
251	if (obd != NULL) {
252		imp = obd->u.cli.cl_import;
253	}
254
255	/* Wait a long time for enqueue - server may have to callback a
256	   lock from another client.  Server will evict the other client if it
257	   doesn't respond reasonably, and then give us the lock. */
258	timeout = ldlm_get_enq_timeout(lock) * 2;
259
260	lwd.lwd_lock = lock;
261
262	if (lock->l_flags & LDLM_FL_NO_TIMEOUT) {
263		LDLM_DEBUG(lock, "waiting indefinitely because of NO_TIMEOUT");
264		lwi = LWI_INTR(interrupted_completion_wait, &lwd);
265	} else {
266		lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(timeout),
267				       ldlm_expired_completion_wait,
268				       interrupted_completion_wait, &lwd);
269	}
270
271	if (imp != NULL) {
272		spin_lock(&imp->imp_lock);
273		lwd.lwd_conn_cnt = imp->imp_conn_cnt;
274		spin_unlock(&imp->imp_lock);
275	}
276
277	if (ns_is_client(ldlm_lock_to_ns(lock)) &&
278	    OBD_FAIL_CHECK_RESET(OBD_FAIL_LDLM_INTR_CP_AST,
279				 OBD_FAIL_LDLM_CP_BL_RACE | OBD_FAIL_ONCE)) {
280		lock->l_flags |= LDLM_FL_FAIL_LOC;
281		rc = -EINTR;
282	} else {
283		/* Go to sleep until the lock is granted or cancelled. */
284		rc = l_wait_event(lock->l_waitq,
285				  is_granted_or_cancelled(lock), &lwi);
286	}
287
288	if (rc) {
289		LDLM_DEBUG(lock, "client-side enqueue waking up: failed (%d)",
290			   rc);
291		return rc;
292	}
293
294	return ldlm_completion_tail(lock);
295}
296EXPORT_SYMBOL(ldlm_completion_ast);
297
298/**
299 * A helper to build a blocking AST function
300 *
301 * Perform a common operation for blocking ASTs:
302 * deferred lock cancellation.
303 *
304 * \param lock the lock blocking or canceling AST was called on
305 * \retval 0
306 * \see mdt_blocking_ast
307 * \see ldlm_blocking_ast
308 */
309int ldlm_blocking_ast_nocheck(struct ldlm_lock *lock)
310{
311	int do_ast;
312
313	lock->l_flags |= LDLM_FL_CBPENDING;
314	do_ast = (!lock->l_readers && !lock->l_writers);
315	unlock_res_and_lock(lock);
316
317	if (do_ast) {
318		struct lustre_handle lockh;
319		int rc;
320
321		LDLM_DEBUG(lock, "already unused, calling ldlm_cli_cancel");
322		ldlm_lock2handle(lock, &lockh);
323		rc = ldlm_cli_cancel(&lockh, LCF_ASYNC);
324		if (rc < 0)
325			CERROR("ldlm_cli_cancel: %d\n", rc);
326	} else {
327		LDLM_DEBUG(lock, "Lock still has references, will be "
328			   "cancelled later");
329	}
330	return 0;
331}
332EXPORT_SYMBOL(ldlm_blocking_ast_nocheck);
333
334/**
335 * Server blocking AST
336 *
337 * ->l_blocking_ast() callback for LDLM locks acquired by server-side
338 * OBDs.
339 *
340 * \param lock the lock which blocks a request or cancelling lock
341 * \param desc unused
342 * \param data unused
343 * \param flag indicates whether this cancelling or blocking callback
344 * \retval 0
345 * \see ldlm_blocking_ast_nocheck
346 */
347int ldlm_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
348		      void *data, int flag)
349{
350	if (flag == LDLM_CB_CANCELING) {
351		/* Don't need to do anything here. */
352		return 0;
353	}
354
355	lock_res_and_lock(lock);
356	/* Get this: if ldlm_blocking_ast is racing with intent_policy, such
357	 * that ldlm_blocking_ast is called just before intent_policy method
358	 * takes the lr_lock, then by the time we get the lock, we might not
359	 * be the correct blocking function anymore.  So check, and return
360	 * early, if so. */
361	if (lock->l_blocking_ast != ldlm_blocking_ast) {
362		unlock_res_and_lock(lock);
363		return 0;
364	}
365	return ldlm_blocking_ast_nocheck(lock);
366}
367EXPORT_SYMBOL(ldlm_blocking_ast);
368
369/**
370 * ->l_glimpse_ast() for DLM extent locks acquired on the server-side. See
371 * comment in filter_intent_policy() on why you may need this.
372 */
373int ldlm_glimpse_ast(struct ldlm_lock *lock, void *reqp)
374{
375	/*
376	 * Returning -ELDLM_NO_LOCK_DATA actually works, but the reason for
377	 * that is rather subtle: with OST-side locking, it may so happen that
378	 * _all_ extent locks are held by the OST. If client wants to obtain
379	 * current file size it calls ll{,u}_glimpse_size(), and (as locks are
380	 * on the server), dummy glimpse callback fires and does
381	 * nothing. Client still receives correct file size due to the
382	 * following fragment in filter_intent_policy():
383	 *
384	 * rc = l->l_glimpse_ast(l, NULL); // this will update the LVB
385	 * if (rc != 0 && res->lr_namespace->ns_lvbo &&
386	 *     res->lr_namespace->ns_lvbo->lvbo_update) {
387	 *	 res->lr_namespace->ns_lvbo->lvbo_update(res, NULL, 0, 1);
388	 * }
389	 *
390	 * that is, after glimpse_ast() fails, filter_lvbo_update() runs, and
391	 * returns correct file size to the client.
392	 */
393	return -ELDLM_NO_LOCK_DATA;
394}
395EXPORT_SYMBOL(ldlm_glimpse_ast);
396
397/**
398 * Enqueue a local lock (typically on a server).
399 */
400int ldlm_cli_enqueue_local(struct ldlm_namespace *ns,
401			   const struct ldlm_res_id *res_id,
402			   ldlm_type_t type, ldlm_policy_data_t *policy,
403			   ldlm_mode_t mode, __u64 *flags,
404			   ldlm_blocking_callback blocking,
405			   ldlm_completion_callback completion,
406			   ldlm_glimpse_callback glimpse,
407			   void *data, __u32 lvb_len, enum lvb_type lvb_type,
408			   const __u64 *client_cookie,
409			   struct lustre_handle *lockh)
410{
411	struct ldlm_lock *lock;
412	int err;
413	const struct ldlm_callback_suite cbs = { .lcs_completion = completion,
414						 .lcs_blocking   = blocking,
415						 .lcs_glimpse    = glimpse,
416	};
417
418	LASSERT(!(*flags & LDLM_FL_REPLAY));
419	if (unlikely(ns_is_client(ns))) {
420		CERROR("Trying to enqueue local lock in a shadow namespace\n");
421		LBUG();
422	}
423
424	lock = ldlm_lock_create(ns, res_id, type, mode, &cbs, data, lvb_len,
425				lvb_type);
426	if (unlikely(!lock)) {
427		err = -ENOMEM;
428		goto out_nolock;
429	}
430
431	ldlm_lock2handle(lock, lockh);
432
433	/* NB: we don't have any lock now (lock_res_and_lock)
434	 * because it's a new lock */
435	ldlm_lock_addref_internal_nolock(lock, mode);
436	lock->l_flags |= LDLM_FL_LOCAL;
437	if (*flags & LDLM_FL_ATOMIC_CB)
438		lock->l_flags |= LDLM_FL_ATOMIC_CB;
439
440	if (policy != NULL)
441		lock->l_policy_data = *policy;
442	if (client_cookie != NULL)
443		lock->l_client_cookie = *client_cookie;
444	if (type == LDLM_EXTENT)
445		lock->l_req_extent = policy->l_extent;
446
447	err = ldlm_lock_enqueue(ns, &lock, policy, flags);
448	if (unlikely(err != ELDLM_OK))
449		goto out;
450
451	if (policy != NULL)
452		*policy = lock->l_policy_data;
453
454	if (lock->l_completion_ast)
455		lock->l_completion_ast(lock, *flags, NULL);
456
457	LDLM_DEBUG(lock, "client-side local enqueue handler, new lock created");
458 out:
459	LDLM_LOCK_RELEASE(lock);
460 out_nolock:
461	return err;
462}
463EXPORT_SYMBOL(ldlm_cli_enqueue_local);
464
465static void failed_lock_cleanup(struct ldlm_namespace *ns,
466				struct ldlm_lock *lock, int mode)
467{
468	int need_cancel = 0;
469
470	/* Set a flag to prevent us from sending a CANCEL (bug 407) */
471	lock_res_and_lock(lock);
472	/* Check that lock is not granted or failed, we might race. */
473	if ((lock->l_req_mode != lock->l_granted_mode) &&
474	    !(lock->l_flags & LDLM_FL_FAILED)) {
475		/* Make sure that this lock will not be found by raced
476		 * bl_ast and -EINVAL reply is sent to server anyways.
477		 * bug 17645 */
478		lock->l_flags |= LDLM_FL_LOCAL_ONLY | LDLM_FL_FAILED |
479				 LDLM_FL_ATOMIC_CB | LDLM_FL_CBPENDING;
480		need_cancel = 1;
481	}
482	unlock_res_and_lock(lock);
483
484	if (need_cancel)
485		LDLM_DEBUG(lock,
486			   "setting FL_LOCAL_ONLY | LDLM_FL_FAILED | "
487			   "LDLM_FL_ATOMIC_CB | LDLM_FL_CBPENDING");
488	else
489		LDLM_DEBUG(lock, "lock was granted or failed in race");
490
491	ldlm_lock_decref_internal(lock, mode);
492
493	/* XXX - HACK because we shouldn't call ldlm_lock_destroy()
494	 *       from llite/file.c/ll_file_flock(). */
495	/* This code makes for the fact that we do not have blocking handler on
496	 * a client for flock locks. As such this is the place where we must
497	 * completely kill failed locks. (interrupted and those that
498	 * were waiting to be granted when server evicted us. */
499	if (lock->l_resource->lr_type == LDLM_FLOCK) {
500		lock_res_and_lock(lock);
501		ldlm_resource_unlink_lock(lock);
502		ldlm_lock_destroy_nolock(lock);
503		unlock_res_and_lock(lock);
504	}
505}
506
507/**
508 * Finishing portion of client lock enqueue code.
509 *
510 * Called after receiving reply from server.
511 */
512int ldlm_cli_enqueue_fini(struct obd_export *exp, struct ptlrpc_request *req,
513			  ldlm_type_t type, __u8 with_policy, ldlm_mode_t mode,
514			  __u64 *flags, void *lvb, __u32 lvb_len,
515			  struct lustre_handle *lockh, int rc)
516{
517	struct ldlm_namespace *ns = exp->exp_obd->obd_namespace;
518	int is_replay = *flags & LDLM_FL_REPLAY;
519	struct ldlm_lock *lock;
520	struct ldlm_reply *reply;
521	int cleanup_phase = 1;
522	int size = 0;
523
524	lock = ldlm_handle2lock(lockh);
525	/* ldlm_cli_enqueue is holding a reference on this lock. */
526	if (!lock) {
527		LASSERT(type == LDLM_FLOCK);
528		return -ENOLCK;
529	}
530
531	LASSERTF(ergo(lvb_len != 0, lvb_len == lock->l_lvb_len),
532		 "lvb_len = %d, l_lvb_len = %d\n", lvb_len, lock->l_lvb_len);
533
534	if (rc != ELDLM_OK) {
535		LASSERT(!is_replay);
536		LDLM_DEBUG(lock, "client-side enqueue END (%s)",
537			   rc == ELDLM_LOCK_ABORTED ? "ABORTED" : "FAILED");
538
539		if (rc != ELDLM_LOCK_ABORTED)
540			goto cleanup;
541	}
542
543	/* Before we return, swab the reply */
544	reply = req_capsule_server_get(&req->rq_pill, &RMF_DLM_REP);
545	if (reply == NULL) {
546		rc = -EPROTO;
547		goto cleanup;
548	}
549
550	if (lvb_len != 0) {
551		LASSERT(lvb != NULL);
552
553		size = req_capsule_get_size(&req->rq_pill, &RMF_DLM_LVB,
554					    RCL_SERVER);
555		if (size < 0) {
556			LDLM_ERROR(lock, "Fail to get lvb_len, rc = %d", size);
557			rc = size;
558			goto cleanup;
559		} else if (unlikely(size > lvb_len)) {
560			LDLM_ERROR(lock, "Replied LVB is larger than "
561				   "expectation, expected = %d, replied = %d",
562				   lvb_len, size);
563			rc = -EINVAL;
564			goto cleanup;
565		}
566	}
567
568	if (rc == ELDLM_LOCK_ABORTED) {
569		if (lvb_len != 0)
570			rc = ldlm_fill_lvb(lock, &req->rq_pill, RCL_SERVER,
571					   lvb, size);
572		if (rc == 0)
573			rc = ELDLM_LOCK_ABORTED;
574		goto cleanup;
575	}
576
577	/* lock enqueued on the server */
578	cleanup_phase = 0;
579
580	lock_res_and_lock(lock);
581	/* Key change rehash lock in per-export hash with new key */
582	if (exp->exp_lock_hash) {
583		/* In the function below, .hs_keycmp resolves to
584		 * ldlm_export_lock_keycmp() */
585		/* coverity[overrun-buffer-val] */
586		cfs_hash_rehash_key(exp->exp_lock_hash,
587				    &lock->l_remote_handle,
588				    &reply->lock_handle,
589				    &lock->l_exp_hash);
590	} else {
591		lock->l_remote_handle = reply->lock_handle;
592	}
593
594	*flags = ldlm_flags_from_wire(reply->lock_flags);
595	lock->l_flags |= ldlm_flags_from_wire(reply->lock_flags &
596					      LDLM_INHERIT_FLAGS);
597	/* move NO_TIMEOUT flag to the lock to force ldlm_lock_match()
598	 * to wait with no timeout as well */
599	lock->l_flags |= ldlm_flags_from_wire(reply->lock_flags &
600					      LDLM_FL_NO_TIMEOUT);
601	unlock_res_and_lock(lock);
602
603	CDEBUG(D_INFO, "local: %p, remote cookie: %#llx, flags: 0x%llx\n",
604	       lock, reply->lock_handle.cookie, *flags);
605
606	/* If enqueue returned a blocked lock but the completion handler has
607	 * already run, then it fixed up the resource and we don't need to do it
608	 * again. */
609	if ((*flags) & LDLM_FL_LOCK_CHANGED) {
610		int newmode = reply->lock_desc.l_req_mode;
611		LASSERT(!is_replay);
612		if (newmode && newmode != lock->l_req_mode) {
613			LDLM_DEBUG(lock, "server returned different mode %s",
614				   ldlm_lockname[newmode]);
615			lock->l_req_mode = newmode;
616		}
617
618		if (!ldlm_res_eq(&reply->lock_desc.l_resource.lr_name,
619				 &lock->l_resource->lr_name)) {
620			CDEBUG(D_INFO, "remote intent success, locking "DLDLMRES
621				       " instead of "DLDLMRES"\n",
622			       PLDLMRES(&reply->lock_desc.l_resource),
623			       PLDLMRES(lock->l_resource));
624
625			rc = ldlm_lock_change_resource(ns, lock,
626					&reply->lock_desc.l_resource.lr_name);
627			if (rc || lock->l_resource == NULL) {
628				rc = -ENOMEM;
629				goto cleanup;
630			}
631			LDLM_DEBUG(lock, "client-side enqueue, new resource");
632		}
633		if (with_policy)
634			if (!(type == LDLM_IBITS &&
635			      !(exp_connect_flags(exp) & OBD_CONNECT_IBITS)))
636				/* We assume lock type cannot change on server*/
637				ldlm_convert_policy_to_local(exp,
638						lock->l_resource->lr_type,
639						&reply->lock_desc.l_policy_data,
640						&lock->l_policy_data);
641		if (type != LDLM_PLAIN)
642			LDLM_DEBUG(lock,
643				   "client-side enqueue, new policy data");
644	}
645
646	if ((*flags) & LDLM_FL_AST_SENT ||
647	    /* Cancel extent locks as soon as possible on a liblustre client,
648	     * because it cannot handle asynchronous ASTs robustly (see
649	     * bug 7311). */
650	    (LIBLUSTRE_CLIENT && type == LDLM_EXTENT)) {
651		lock_res_and_lock(lock);
652		lock->l_flags |= LDLM_FL_CBPENDING |  LDLM_FL_BL_AST;
653		unlock_res_and_lock(lock);
654		LDLM_DEBUG(lock, "enqueue reply includes blocking AST");
655	}
656
657	/* If the lock has already been granted by a completion AST, don't
658	 * clobber the LVB with an older one. */
659	if (lvb_len != 0) {
660		/* We must lock or a racing completion might update lvb without
661		 * letting us know and we'll clobber the correct value.
662		 * Cannot unlock after the check either, a that still leaves
663		 * a tiny window for completion to get in */
664		lock_res_and_lock(lock);
665		if (lock->l_req_mode != lock->l_granted_mode)
666			rc = ldlm_fill_lvb(lock, &req->rq_pill, RCL_SERVER,
667					   lock->l_lvb_data, size);
668		unlock_res_and_lock(lock);
669		if (rc < 0) {
670			cleanup_phase = 1;
671			goto cleanup;
672		}
673	}
674
675	if (!is_replay) {
676		rc = ldlm_lock_enqueue(ns, &lock, NULL, flags);
677		if (lock->l_completion_ast != NULL) {
678			int err = lock->l_completion_ast(lock, *flags, NULL);
679			if (!rc)
680				rc = err;
681			if (rc)
682				cleanup_phase = 1;
683		}
684	}
685
686	if (lvb_len && lvb != NULL) {
687		/* Copy the LVB here, and not earlier, because the completion
688		 * AST (if any) can override what we got in the reply */
689		memcpy(lvb, lock->l_lvb_data, lvb_len);
690	}
691
692	LDLM_DEBUG(lock, "client-side enqueue END");
693cleanup:
694	if (cleanup_phase == 1 && rc)
695		failed_lock_cleanup(ns, lock, mode);
696	/* Put lock 2 times, the second reference is held by ldlm_cli_enqueue */
697	LDLM_LOCK_PUT(lock);
698	LDLM_LOCK_RELEASE(lock);
699	return rc;
700}
701EXPORT_SYMBOL(ldlm_cli_enqueue_fini);
702
703/**
704 * Estimate number of lock handles that would fit into request of given
705 * size.  PAGE_SIZE-512 is to allow TCP/IP and LNET headers to fit into
706 * a single page on the send/receive side. XXX: 512 should be changed to
707 * more adequate value.
708 */
709static inline int ldlm_req_handles_avail(int req_size, int off)
710{
711	int avail;
712
713	avail = min_t(int, LDLM_MAXREQSIZE, PAGE_CACHE_SIZE - 512) - req_size;
714	if (likely(avail >= 0))
715		avail /= (int)sizeof(struct lustre_handle);
716	else
717		avail = 0;
718	avail += LDLM_LOCKREQ_HANDLES - off;
719
720	return avail;
721}
722
723static inline int ldlm_capsule_handles_avail(struct req_capsule *pill,
724					     enum req_location loc,
725					     int off)
726{
727	int size = req_capsule_msg_size(pill, loc);
728	return ldlm_req_handles_avail(size, off);
729}
730
731static inline int ldlm_format_handles_avail(struct obd_import *imp,
732					    const struct req_format *fmt,
733					    enum req_location loc, int off)
734{
735	int size = req_capsule_fmt_size(imp->imp_msg_magic, fmt, loc);
736	return ldlm_req_handles_avail(size, off);
737}
738
739/**
740 * Cancel LRU locks and pack them into the enqueue request. Pack there the given
741 * \a count locks in \a cancels.
742 *
743 * This is to be called by functions preparing their own requests that
744 * might contain lists of locks to cancel in addition to actual operation
745 * that needs to be performed.
746 */
747int ldlm_prep_elc_req(struct obd_export *exp, struct ptlrpc_request *req,
748		      int version, int opc, int canceloff,
749		      struct list_head *cancels, int count)
750{
751	struct ldlm_namespace   *ns = exp->exp_obd->obd_namespace;
752	struct req_capsule      *pill = &req->rq_pill;
753	struct ldlm_request     *dlm = NULL;
754	int flags, avail, to_free, pack = 0;
755	LIST_HEAD(head);
756	int rc;
757
758	if (cancels == NULL)
759		cancels = &head;
760	if (ns_connect_cancelset(ns)) {
761		/* Estimate the amount of available space in the request. */
762		req_capsule_filled_sizes(pill, RCL_CLIENT);
763		avail = ldlm_capsule_handles_avail(pill, RCL_CLIENT, canceloff);
764
765		flags = ns_connect_lru_resize(ns) ?
766			LDLM_CANCEL_LRUR : LDLM_CANCEL_AGED;
767		to_free = !ns_connect_lru_resize(ns) &&
768			  opc == LDLM_ENQUEUE ? 1 : 0;
769
770		/* Cancel LRU locks here _only_ if the server supports
771		 * EARLY_CANCEL. Otherwise we have to send extra CANCEL
772		 * RPC, which will make us slower. */
773		if (avail > count)
774			count += ldlm_cancel_lru_local(ns, cancels, to_free,
775						       avail - count, 0, flags);
776		if (avail > count)
777			pack = count;
778		else
779			pack = avail;
780		req_capsule_set_size(pill, &RMF_DLM_REQ, RCL_CLIENT,
781				     ldlm_request_bufsize(pack, opc));
782	}
783
784	rc = ptlrpc_request_pack(req, version, opc);
785	if (rc) {
786		ldlm_lock_list_put(cancels, l_bl_ast, count);
787		return rc;
788	}
789
790	if (ns_connect_cancelset(ns)) {
791		if (canceloff) {
792			dlm = req_capsule_client_get(pill, &RMF_DLM_REQ);
793			LASSERT(dlm);
794			/* Skip first lock handler in ldlm_request_pack(),
795			 * this method will increment @lock_count according
796			 * to the lock handle amount actually written to
797			 * the buffer. */
798			dlm->lock_count = canceloff;
799		}
800		/* Pack into the request @pack lock handles. */
801		ldlm_cli_cancel_list(cancels, pack, req, 0);
802		/* Prepare and send separate cancel RPC for others. */
803		ldlm_cli_cancel_list(cancels, count - pack, NULL, 0);
804	} else {
805		ldlm_lock_list_put(cancels, l_bl_ast, count);
806	}
807	return 0;
808}
809EXPORT_SYMBOL(ldlm_prep_elc_req);
810
811int ldlm_prep_enqueue_req(struct obd_export *exp, struct ptlrpc_request *req,
812			  struct list_head *cancels, int count)
813{
814	return ldlm_prep_elc_req(exp, req, LUSTRE_DLM_VERSION, LDLM_ENQUEUE,
815				 LDLM_ENQUEUE_CANCEL_OFF, cancels, count);
816}
817EXPORT_SYMBOL(ldlm_prep_enqueue_req);
818
819struct ptlrpc_request *ldlm_enqueue_pack(struct obd_export *exp, int lvb_len)
820{
821	struct ptlrpc_request *req;
822	int rc;
823
824	req = ptlrpc_request_alloc(class_exp2cliimp(exp), &RQF_LDLM_ENQUEUE);
825	if (req == NULL)
826		return ERR_PTR(-ENOMEM);
827
828	rc = ldlm_prep_enqueue_req(exp, req, NULL, 0);
829	if (rc) {
830		ptlrpc_request_free(req);
831		return ERR_PTR(rc);
832	}
833
834	req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER, lvb_len);
835	ptlrpc_request_set_replen(req);
836	return req;
837}
838EXPORT_SYMBOL(ldlm_enqueue_pack);
839
840/**
841 * Client-side lock enqueue.
842 *
843 * If a request has some specific initialisation it is passed in \a reqp,
844 * otherwise it is created in ldlm_cli_enqueue.
845 *
846 * Supports sync and async requests, pass \a async flag accordingly. If a
847 * request was created in ldlm_cli_enqueue and it is the async request,
848 * pass it to the caller in \a reqp.
849 */
850int ldlm_cli_enqueue(struct obd_export *exp, struct ptlrpc_request **reqp,
851		     struct ldlm_enqueue_info *einfo,
852		     const struct ldlm_res_id *res_id,
853		     ldlm_policy_data_t const *policy, __u64 *flags,
854		     void *lvb, __u32 lvb_len, enum lvb_type lvb_type,
855		     struct lustre_handle *lockh, int async)
856{
857	struct ldlm_namespace *ns;
858	struct ldlm_lock      *lock;
859	struct ldlm_request   *body;
860	int		    is_replay = *flags & LDLM_FL_REPLAY;
861	int		    req_passed_in = 1;
862	int		    rc, err;
863	struct ptlrpc_request *req;
864
865	LASSERT(exp != NULL);
866
867	ns = exp->exp_obd->obd_namespace;
868
869	/* If we're replaying this lock, just check some invariants.
870	 * If we're creating a new lock, get everything all setup nice. */
871	if (is_replay) {
872		lock = ldlm_handle2lock_long(lockh, 0);
873		LASSERT(lock != NULL);
874		LDLM_DEBUG(lock, "client-side enqueue START");
875		LASSERT(exp == lock->l_conn_export);
876	} else {
877		const struct ldlm_callback_suite cbs = {
878			.lcs_completion = einfo->ei_cb_cp,
879			.lcs_blocking	= einfo->ei_cb_bl,
880			.lcs_glimpse	= einfo->ei_cb_gl
881		};
882		lock = ldlm_lock_create(ns, res_id, einfo->ei_type,
883					einfo->ei_mode, &cbs, einfo->ei_cbdata,
884					lvb_len, lvb_type);
885		if (lock == NULL)
886			return -ENOMEM;
887		/* for the local lock, add the reference */
888		ldlm_lock_addref_internal(lock, einfo->ei_mode);
889		ldlm_lock2handle(lock, lockh);
890		if (policy != NULL)
891				lock->l_policy_data = *policy;
892
893		if (einfo->ei_type == LDLM_EXTENT)
894			lock->l_req_extent = policy->l_extent;
895		LDLM_DEBUG(lock, "client-side enqueue START, flags %llx\n",
896			   *flags);
897	}
898
899	lock->l_conn_export = exp;
900	lock->l_export = NULL;
901	lock->l_blocking_ast = einfo->ei_cb_bl;
902	lock->l_flags |= (*flags & (LDLM_FL_NO_LRU | LDLM_FL_EXCL));
903
904	/* lock not sent to server yet */
905
906	if (reqp == NULL || *reqp == NULL) {
907		req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
908						&RQF_LDLM_ENQUEUE,
909						LUSTRE_DLM_VERSION,
910						LDLM_ENQUEUE);
911		if (req == NULL) {
912			failed_lock_cleanup(ns, lock, einfo->ei_mode);
913			LDLM_LOCK_RELEASE(lock);
914			return -ENOMEM;
915		}
916		req_passed_in = 0;
917		if (reqp)
918			*reqp = req;
919	} else {
920		int len;
921
922		req = *reqp;
923		len = req_capsule_get_size(&req->rq_pill, &RMF_DLM_REQ,
924					   RCL_CLIENT);
925		LASSERTF(len >= sizeof(*body), "buflen[%d] = %d, not %d\n",
926			 DLM_LOCKREQ_OFF, len, (int)sizeof(*body));
927	}
928
929	/* Dump lock data into the request buffer */
930	body = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
931	ldlm_lock2desc(lock, &body->lock_desc);
932	body->lock_flags = ldlm_flags_to_wire(*flags);
933	body->lock_handle[0] = *lockh;
934
935	/* Continue as normal. */
936	if (!req_passed_in) {
937		if (lvb_len > 0)
938			req_capsule_extend(&req->rq_pill,
939					   &RQF_LDLM_ENQUEUE_LVB);
940		req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
941				     lvb_len);
942		ptlrpc_request_set_replen(req);
943	}
944
945	/*
946	 * Liblustre client doesn't get extent locks, except for O_APPEND case
947	 * where [0, OBD_OBJECT_EOF] lock is taken, or truncate, where
948	 * [i_size, OBD_OBJECT_EOF] lock is taken.
949	 */
950	LASSERT(ergo(LIBLUSTRE_CLIENT, einfo->ei_type != LDLM_EXTENT ||
951		     policy->l_extent.end == OBD_OBJECT_EOF));
952
953	if (async) {
954		LASSERT(reqp != NULL);
955		return 0;
956	}
957
958	LDLM_DEBUG(lock, "sending request");
959
960	rc = ptlrpc_queue_wait(req);
961
962	err = ldlm_cli_enqueue_fini(exp, req, einfo->ei_type, policy ? 1 : 0,
963				    einfo->ei_mode, flags, lvb, lvb_len,
964				    lockh, rc);
965
966	/* If ldlm_cli_enqueue_fini did not find the lock, we need to free
967	 * one reference that we took */
968	if (err == -ENOLCK)
969		LDLM_LOCK_RELEASE(lock);
970	else
971		rc = err;
972
973	if (!req_passed_in && req != NULL) {
974		ptlrpc_req_finished(req);
975		if (reqp)
976			*reqp = NULL;
977	}
978
979	return rc;
980}
981EXPORT_SYMBOL(ldlm_cli_enqueue);
982
983static int ldlm_cli_convert_local(struct ldlm_lock *lock, int new_mode,
984				  __u32 *flags)
985{
986	struct ldlm_resource *res;
987	int rc;
988
989	if (ns_is_client(ldlm_lock_to_ns(lock))) {
990		CERROR("Trying to cancel local lock\n");
991		LBUG();
992	}
993	LDLM_DEBUG(lock, "client-side local convert");
994
995	res = ldlm_lock_convert(lock, new_mode, flags);
996	if (res) {
997		ldlm_reprocess_all(res);
998		rc = 0;
999	} else {
1000		rc = LUSTRE_EDEADLK;
1001	}
1002	LDLM_DEBUG(lock, "client-side local convert handler END");
1003	LDLM_LOCK_PUT(lock);
1004	return rc;
1005}
1006
1007/* FIXME: one of ldlm_cli_convert or the server side should reject attempted
1008 * conversion of locks which are on the waiting or converting queue */
1009/* Caller of this code is supposed to take care of lock readers/writers
1010   accounting */
1011int ldlm_cli_convert(struct lustre_handle *lockh, int new_mode, __u32 *flags)
1012{
1013	struct ldlm_request   *body;
1014	struct ldlm_reply     *reply;
1015	struct ldlm_lock      *lock;
1016	struct ldlm_resource  *res;
1017	struct ptlrpc_request *req;
1018	int		    rc;
1019
1020	lock = ldlm_handle2lock(lockh);
1021	if (!lock) {
1022		LBUG();
1023		return -EINVAL;
1024	}
1025	*flags = 0;
1026
1027	if (lock->l_conn_export == NULL)
1028		return ldlm_cli_convert_local(lock, new_mode, flags);
1029
1030	LDLM_DEBUG(lock, "client-side convert");
1031
1032	req = ptlrpc_request_alloc_pack(class_exp2cliimp(lock->l_conn_export),
1033					&RQF_LDLM_CONVERT, LUSTRE_DLM_VERSION,
1034					LDLM_CONVERT);
1035	if (req == NULL) {
1036		LDLM_LOCK_PUT(lock);
1037		return -ENOMEM;
1038	}
1039
1040	body = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
1041	body->lock_handle[0] = lock->l_remote_handle;
1042
1043	body->lock_desc.l_req_mode = new_mode;
1044	body->lock_flags = ldlm_flags_to_wire(*flags);
1045
1046
1047	ptlrpc_request_set_replen(req);
1048	rc = ptlrpc_queue_wait(req);
1049	if (rc != ELDLM_OK)
1050		goto out;
1051
1052	reply = req_capsule_server_get(&req->rq_pill, &RMF_DLM_REP);
1053	if (reply == NULL) {
1054		rc = -EPROTO;
1055		goto out;
1056	}
1057
1058	if (req->rq_status) {
1059		rc = req->rq_status;
1060		goto out;
1061	}
1062
1063	res = ldlm_lock_convert(lock, new_mode, &reply->lock_flags);
1064	if (res != NULL) {
1065		ldlm_reprocess_all(res);
1066		/* Go to sleep until the lock is granted. */
1067		/* FIXME: or cancelled. */
1068		if (lock->l_completion_ast) {
1069			rc = lock->l_completion_ast(lock, LDLM_FL_WAIT_NOREPROC,
1070						    NULL);
1071			if (rc)
1072				goto out;
1073		}
1074	} else {
1075		rc = LUSTRE_EDEADLK;
1076	}
1077 out:
1078	LDLM_LOCK_PUT(lock);
1079	ptlrpc_req_finished(req);
1080	return rc;
1081}
1082EXPORT_SYMBOL(ldlm_cli_convert);
1083
1084/**
1085 * Cancel locks locally.
1086 * Returns:
1087 * \retval LDLM_FL_LOCAL_ONLY if there is no need for a CANCEL RPC to the server
1088 * \retval LDLM_FL_CANCELING otherwise;
1089 * \retval LDLM_FL_BL_AST if there is a need for a separate CANCEL RPC.
1090 */
1091static __u64 ldlm_cli_cancel_local(struct ldlm_lock *lock)
1092{
1093	__u64 rc = LDLM_FL_LOCAL_ONLY;
1094
1095	if (lock->l_conn_export) {
1096		bool local_only;
1097
1098		LDLM_DEBUG(lock, "client-side cancel");
1099		/* Set this flag to prevent others from getting new references*/
1100		lock_res_and_lock(lock);
1101		lock->l_flags |= LDLM_FL_CBPENDING;
1102		local_only = !!(lock->l_flags &
1103				(LDLM_FL_LOCAL_ONLY|LDLM_FL_CANCEL_ON_BLOCK));
1104		ldlm_cancel_callback(lock);
1105		rc = (lock->l_flags & LDLM_FL_BL_AST) ?
1106			LDLM_FL_BL_AST : LDLM_FL_CANCELING;
1107		unlock_res_and_lock(lock);
1108
1109		if (local_only) {
1110			CDEBUG(D_DLMTRACE, "not sending request (at caller's "
1111			       "instruction)\n");
1112			rc = LDLM_FL_LOCAL_ONLY;
1113		}
1114		ldlm_lock_cancel(lock);
1115	} else {
1116		if (ns_is_client(ldlm_lock_to_ns(lock))) {
1117			LDLM_ERROR(lock, "Trying to cancel local lock");
1118			LBUG();
1119		}
1120		LDLM_DEBUG(lock, "server-side local cancel");
1121		ldlm_lock_cancel(lock);
1122		ldlm_reprocess_all(lock->l_resource);
1123	}
1124
1125	return rc;
1126}
1127
1128/**
1129 * Pack \a count locks in \a head into ldlm_request buffer of request \a req.
1130 */
1131static void ldlm_cancel_pack(struct ptlrpc_request *req,
1132			     struct list_head *head, int count)
1133{
1134	struct ldlm_request *dlm;
1135	struct ldlm_lock *lock;
1136	int max, packed = 0;
1137
1138	dlm = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
1139	LASSERT(dlm != NULL);
1140
1141	/* Check the room in the request buffer. */
1142	max = req_capsule_get_size(&req->rq_pill, &RMF_DLM_REQ, RCL_CLIENT) -
1143		sizeof(struct ldlm_request);
1144	max /= sizeof(struct lustre_handle);
1145	max += LDLM_LOCKREQ_HANDLES;
1146	LASSERT(max >= dlm->lock_count + count);
1147
1148	/* XXX: it would be better to pack lock handles grouped by resource.
1149	 * so that the server cancel would call filter_lvbo_update() less
1150	 * frequently. */
1151	list_for_each_entry(lock, head, l_bl_ast) {
1152		if (!count--)
1153			break;
1154		LASSERT(lock->l_conn_export);
1155		/* Pack the lock handle to the given request buffer. */
1156		LDLM_DEBUG(lock, "packing");
1157		dlm->lock_handle[dlm->lock_count++] = lock->l_remote_handle;
1158		packed++;
1159	}
1160	CDEBUG(D_DLMTRACE, "%d locks packed\n", packed);
1161}
1162
1163/**
1164 * Prepare and send a batched cancel RPC. It will include \a count lock
1165 * handles of locks given in \a cancels list. */
1166int ldlm_cli_cancel_req(struct obd_export *exp, struct list_head *cancels,
1167			int count, ldlm_cancel_flags_t flags)
1168{
1169	struct ptlrpc_request *req = NULL;
1170	struct obd_import *imp;
1171	int free, sent = 0;
1172	int rc = 0;
1173
1174	LASSERT(exp != NULL);
1175	LASSERT(count > 0);
1176
1177	CFS_FAIL_TIMEOUT(OBD_FAIL_LDLM_PAUSE_CANCEL, cfs_fail_val);
1178
1179	if (CFS_FAIL_CHECK(OBD_FAIL_LDLM_CANCEL_RACE))
1180		return count;
1181
1182	free = ldlm_format_handles_avail(class_exp2cliimp(exp),
1183					 &RQF_LDLM_CANCEL, RCL_CLIENT, 0);
1184	if (count > free)
1185		count = free;
1186
1187	while (1) {
1188		imp = class_exp2cliimp(exp);
1189		if (imp == NULL || imp->imp_invalid) {
1190			CDEBUG(D_DLMTRACE,
1191			       "skipping cancel on invalid import %p\n", imp);
1192			return count;
1193		}
1194
1195		req = ptlrpc_request_alloc(imp, &RQF_LDLM_CANCEL);
1196		if (req == NULL) {
1197			rc = -ENOMEM;
1198			goto out;
1199		}
1200
1201		req_capsule_filled_sizes(&req->rq_pill, RCL_CLIENT);
1202		req_capsule_set_size(&req->rq_pill, &RMF_DLM_REQ, RCL_CLIENT,
1203				     ldlm_request_bufsize(count, LDLM_CANCEL));
1204
1205		rc = ptlrpc_request_pack(req, LUSTRE_DLM_VERSION, LDLM_CANCEL);
1206		if (rc) {
1207			ptlrpc_request_free(req);
1208			goto out;
1209		}
1210
1211		req->rq_request_portal = LDLM_CANCEL_REQUEST_PORTAL;
1212		req->rq_reply_portal = LDLM_CANCEL_REPLY_PORTAL;
1213		ptlrpc_at_set_req_timeout(req);
1214
1215		ldlm_cancel_pack(req, cancels, count);
1216
1217		ptlrpc_request_set_replen(req);
1218		if (flags & LCF_ASYNC) {
1219			ptlrpcd_add_req(req, PDL_POLICY_LOCAL, -1);
1220			sent = count;
1221			goto out;
1222		} else {
1223			rc = ptlrpc_queue_wait(req);
1224		}
1225		if (rc == LUSTRE_ESTALE) {
1226			CDEBUG(D_DLMTRACE, "client/server (nid %s) "
1227			       "out of sync -- not fatal\n",
1228			       libcfs_nid2str(req->rq_import->
1229					      imp_connection->c_peer.nid));
1230			rc = 0;
1231		} else if (rc == -ETIMEDOUT && /* check there was no reconnect*/
1232			   req->rq_import_generation == imp->imp_generation) {
1233			ptlrpc_req_finished(req);
1234			continue;
1235		} else if (rc != ELDLM_OK) {
1236			/* -ESHUTDOWN is common on umount */
1237			CDEBUG_LIMIT(rc == -ESHUTDOWN ? D_DLMTRACE : D_ERROR,
1238				     "Got rc %d from cancel RPC: "
1239				     "canceling anyway\n", rc);
1240			break;
1241		}
1242		sent = count;
1243		break;
1244	}
1245
1246	ptlrpc_req_finished(req);
1247out:
1248	return sent ? sent : rc;
1249}
1250EXPORT_SYMBOL(ldlm_cli_cancel_req);
1251
1252static inline struct ldlm_pool *ldlm_imp2pl(struct obd_import *imp)
1253{
1254	LASSERT(imp != NULL);
1255	return &imp->imp_obd->obd_namespace->ns_pool;
1256}
1257
1258/**
1259 * Update client's OBD pool related fields with new SLV and Limit from \a req.
1260 */
1261int ldlm_cli_update_pool(struct ptlrpc_request *req)
1262{
1263	struct obd_device *obd;
1264	__u64 new_slv;
1265	__u32 new_limit;
1266
1267	if (unlikely(!req->rq_import || !req->rq_import->imp_obd ||
1268		     !imp_connect_lru_resize(req->rq_import))) {
1269		/*
1270		 * Do nothing for corner cases.
1271		 */
1272		return 0;
1273	}
1274
1275	/* In some cases RPC may contain SLV and limit zeroed out. This
1276	 * is the case when server does not support LRU resize feature.
1277	 * This is also possible in some recovery cases when server-side
1278	 * reqs have no reference to the OBD export and thus access to
1279	 * server-side namespace is not possible. */
1280	if (lustre_msg_get_slv(req->rq_repmsg) == 0 ||
1281	    lustre_msg_get_limit(req->rq_repmsg) == 0) {
1282		DEBUG_REQ(D_HA, req, "Zero SLV or Limit found (SLV: %llu, Limit: %u)",
1283			  lustre_msg_get_slv(req->rq_repmsg),
1284			  lustre_msg_get_limit(req->rq_repmsg));
1285		return 0;
1286	}
1287
1288	new_limit = lustre_msg_get_limit(req->rq_repmsg);
1289	new_slv = lustre_msg_get_slv(req->rq_repmsg);
1290	obd = req->rq_import->imp_obd;
1291
1292	/* Set new SLV and limit in OBD fields to make them accessible
1293	 * to the pool thread. We do not access obd_namespace and pool
1294	 * directly here as there is no reliable way to make sure that
1295	 * they are still alive at cleanup time. Evil races are possible
1296	 * which may cause Oops at that time. */
1297	write_lock(&obd->obd_pool_lock);
1298	obd->obd_pool_slv = new_slv;
1299	obd->obd_pool_limit = new_limit;
1300	write_unlock(&obd->obd_pool_lock);
1301
1302	return 0;
1303}
1304EXPORT_SYMBOL(ldlm_cli_update_pool);
1305
1306/**
1307 * Client side lock cancel.
1308 *
1309 * Lock must not have any readers or writers by this time.
1310 */
1311int ldlm_cli_cancel(struct lustre_handle *lockh,
1312		    ldlm_cancel_flags_t cancel_flags)
1313{
1314	struct obd_export *exp;
1315	int avail, flags, count = 1;
1316	__u64 rc = 0;
1317	struct ldlm_namespace *ns;
1318	struct ldlm_lock *lock;
1319	LIST_HEAD(cancels);
1320
1321	/* concurrent cancels on the same handle can happen */
1322	lock = ldlm_handle2lock_long(lockh, LDLM_FL_CANCELING);
1323	if (lock == NULL) {
1324		LDLM_DEBUG_NOLOCK("lock is already being destroyed\n");
1325		return 0;
1326	}
1327
1328	rc = ldlm_cli_cancel_local(lock);
1329	if (rc == LDLM_FL_LOCAL_ONLY || cancel_flags & LCF_LOCAL) {
1330		LDLM_LOCK_RELEASE(lock);
1331		return 0;
1332	}
1333	/* Even if the lock is marked as LDLM_FL_BL_AST, this is a LDLM_CANCEL
1334	 * RPC which goes to canceld portal, so we can cancel other LRU locks
1335	 * here and send them all as one LDLM_CANCEL RPC. */
1336	LASSERT(list_empty(&lock->l_bl_ast));
1337	list_add(&lock->l_bl_ast, &cancels);
1338
1339	exp = lock->l_conn_export;
1340	if (exp_connect_cancelset(exp)) {
1341		avail = ldlm_format_handles_avail(class_exp2cliimp(exp),
1342						  &RQF_LDLM_CANCEL,
1343						  RCL_CLIENT, 0);
1344		LASSERT(avail > 0);
1345
1346		ns = ldlm_lock_to_ns(lock);
1347		flags = ns_connect_lru_resize(ns) ?
1348			LDLM_CANCEL_LRUR : LDLM_CANCEL_AGED;
1349		count += ldlm_cancel_lru_local(ns, &cancels, 0, avail - 1,
1350					       LCF_BL_AST, flags);
1351	}
1352	ldlm_cli_cancel_list(&cancels, count, NULL, cancel_flags);
1353	return 0;
1354}
1355EXPORT_SYMBOL(ldlm_cli_cancel);
1356
1357/**
1358 * Locally cancel up to \a count locks in list \a cancels.
1359 * Return the number of cancelled locks.
1360 */
1361int ldlm_cli_cancel_list_local(struct list_head *cancels, int count,
1362			       ldlm_cancel_flags_t flags)
1363{
1364	LIST_HEAD(head);
1365	struct ldlm_lock *lock, *next;
1366	int left = 0, bl_ast = 0;
1367	__u64 rc;
1368
1369	left = count;
1370	list_for_each_entry_safe(lock, next, cancels, l_bl_ast) {
1371		if (left-- == 0)
1372			break;
1373
1374		if (flags & LCF_LOCAL) {
1375			rc = LDLM_FL_LOCAL_ONLY;
1376			ldlm_lock_cancel(lock);
1377		} else {
1378			rc = ldlm_cli_cancel_local(lock);
1379		}
1380		/* Until we have compound requests and can send LDLM_CANCEL
1381		 * requests batched with generic RPCs, we need to send cancels
1382		 * with the LDLM_FL_BL_AST flag in a separate RPC from
1383		 * the one being generated now. */
1384		if (!(flags & LCF_BL_AST) && (rc == LDLM_FL_BL_AST)) {
1385			LDLM_DEBUG(lock, "Cancel lock separately");
1386			list_del_init(&lock->l_bl_ast);
1387			list_add(&lock->l_bl_ast, &head);
1388			bl_ast++;
1389			continue;
1390		}
1391		if (rc == LDLM_FL_LOCAL_ONLY) {
1392			/* CANCEL RPC should not be sent to server. */
1393			list_del_init(&lock->l_bl_ast);
1394			LDLM_LOCK_RELEASE(lock);
1395			count--;
1396		}
1397	}
1398	if (bl_ast > 0) {
1399		count -= bl_ast;
1400		ldlm_cli_cancel_list(&head, bl_ast, NULL, 0);
1401	}
1402
1403	return count;
1404}
1405EXPORT_SYMBOL(ldlm_cli_cancel_list_local);
1406
1407/**
1408 * Cancel as many locks as possible w/o sending any RPCs (e.g. to write back
1409 * dirty data, to close a file, ...) or waiting for any RPCs in-flight (e.g.
1410 * readahead requests, ...)
1411 */
1412static ldlm_policy_res_t ldlm_cancel_no_wait_policy(struct ldlm_namespace *ns,
1413						    struct ldlm_lock *lock,
1414						    int unused, int added,
1415						    int count)
1416{
1417	ldlm_policy_res_t result = LDLM_POLICY_CANCEL_LOCK;
1418	ldlm_cancel_for_recovery cb = ns->ns_cancel_for_recovery;
1419	lock_res_and_lock(lock);
1420
1421	/* don't check added & count since we want to process all locks
1422	 * from unused list */
1423	switch (lock->l_resource->lr_type) {
1424		case LDLM_EXTENT:
1425		case LDLM_IBITS:
1426			if (cb && cb(lock))
1427				break;
1428		default:
1429			result = LDLM_POLICY_SKIP_LOCK;
1430			lock->l_flags |= LDLM_FL_SKIPPED;
1431			break;
1432	}
1433
1434	unlock_res_and_lock(lock);
1435	return result;
1436}
1437
1438/**
1439 * Callback function for LRU-resize policy. Decides whether to keep
1440 * \a lock in LRU for current \a LRU size \a unused, added in current
1441 * scan \a added and number of locks to be preferably canceled \a count.
1442 *
1443 * \retval LDLM_POLICY_KEEP_LOCK keep lock in LRU in stop scanning
1444 *
1445 * \retval LDLM_POLICY_CANCEL_LOCK cancel lock from LRU
1446 */
1447static ldlm_policy_res_t ldlm_cancel_lrur_policy(struct ldlm_namespace *ns,
1448						 struct ldlm_lock *lock,
1449						 int unused, int added,
1450						 int count)
1451{
1452	unsigned long cur = cfs_time_current();
1453	struct ldlm_pool *pl = &ns->ns_pool;
1454	__u64 slv, lvf, lv;
1455	unsigned long la;
1456
1457	/* Stop LRU processing when we reach past @count or have checked all
1458	 * locks in LRU. */
1459	if (count && added >= count)
1460		return LDLM_POLICY_KEEP_LOCK;
1461
1462	slv = ldlm_pool_get_slv(pl);
1463	lvf = ldlm_pool_get_lvf(pl);
1464	la = cfs_duration_sec(cfs_time_sub(cur,
1465			      lock->l_last_used));
1466	lv = lvf * la * unused;
1467
1468	/* Inform pool about current CLV to see it via proc. */
1469	ldlm_pool_set_clv(pl, lv);
1470
1471	/* Stop when SLV is not yet come from server or lv is smaller than
1472	 * it is. */
1473	return (slv == 0 || lv < slv) ?
1474		LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
1475}
1476
1477/**
1478 * Callback function for proc used policy. Makes decision whether to keep
1479 * \a lock in LRU for current \a LRU size \a unused, added in current scan \a
1480 * added and number of locks to be preferably canceled \a count.
1481 *
1482 * \retval LDLM_POLICY_KEEP_LOCK keep lock in LRU in stop scanning
1483 *
1484 * \retval LDLM_POLICY_CANCEL_LOCK cancel lock from LRU
1485 */
1486static ldlm_policy_res_t ldlm_cancel_passed_policy(struct ldlm_namespace *ns,
1487						   struct ldlm_lock *lock,
1488						   int unused, int added,
1489						   int count)
1490{
1491	/* Stop LRU processing when we reach past @count or have checked all
1492	 * locks in LRU. */
1493	return (added >= count) ?
1494		LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
1495}
1496
1497/**
1498 * Callback function for aged policy. Makes decision whether to keep \a lock in
1499 * LRU for current LRU size \a unused, added in current scan \a added and
1500 * number of locks to be preferably canceled \a count.
1501 *
1502 * \retval LDLM_POLICY_KEEP_LOCK keep lock in LRU in stop scanning
1503 *
1504 * \retval LDLM_POLICY_CANCEL_LOCK cancel lock from LRU
1505 */
1506static ldlm_policy_res_t ldlm_cancel_aged_policy(struct ldlm_namespace *ns,
1507						 struct ldlm_lock *lock,
1508						 int unused, int added,
1509						 int count)
1510{
1511	/* Stop LRU processing if young lock is found and we reach past count */
1512	return ((added >= count) &&
1513		time_before(cfs_time_current(),
1514			    cfs_time_add(lock->l_last_used, ns->ns_max_age))) ?
1515		LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
1516}
1517
1518/**
1519 * Callback function for default policy. Makes decision whether to keep \a lock
1520 * in LRU for current LRU size \a unused, added in current scan \a added and
1521 * number of locks to be preferably canceled \a count.
1522 *
1523 * \retval LDLM_POLICY_KEEP_LOCK keep lock in LRU in stop scanning
1524 *
1525 * \retval LDLM_POLICY_CANCEL_LOCK cancel lock from LRU
1526 */
1527static ldlm_policy_res_t ldlm_cancel_default_policy(struct ldlm_namespace *ns,
1528						    struct ldlm_lock *lock,
1529						    int unused, int added,
1530						    int count)
1531{
1532	/* Stop LRU processing when we reach past count or have checked all
1533	 * locks in LRU. */
1534	return (added >= count) ?
1535		LDLM_POLICY_KEEP_LOCK : LDLM_POLICY_CANCEL_LOCK;
1536}
1537
1538typedef ldlm_policy_res_t (*ldlm_cancel_lru_policy_t)(struct ldlm_namespace *,
1539						      struct ldlm_lock *, int,
1540						      int, int);
1541
1542static ldlm_cancel_lru_policy_t
1543ldlm_cancel_lru_policy(struct ldlm_namespace *ns, int flags)
1544{
1545	if (flags & LDLM_CANCEL_NO_WAIT)
1546		return ldlm_cancel_no_wait_policy;
1547
1548	if (ns_connect_lru_resize(ns)) {
1549		if (flags & LDLM_CANCEL_SHRINK)
1550			/* We kill passed number of old locks. */
1551			return ldlm_cancel_passed_policy;
1552		else if (flags & LDLM_CANCEL_LRUR)
1553			return ldlm_cancel_lrur_policy;
1554		else if (flags & LDLM_CANCEL_PASSED)
1555			return ldlm_cancel_passed_policy;
1556	} else {
1557		if (flags & LDLM_CANCEL_AGED)
1558			return ldlm_cancel_aged_policy;
1559	}
1560
1561	return ldlm_cancel_default_policy;
1562}
1563
1564/**
1565 * - Free space in LRU for \a count new locks,
1566 *   redundant unused locks are canceled locally;
1567 * - also cancel locally unused aged locks;
1568 * - do not cancel more than \a max locks;
1569 * - GET the found locks and add them into the \a cancels list.
1570 *
1571 * A client lock can be added to the l_bl_ast list only when it is
1572 * marked LDLM_FL_CANCELING. Otherwise, somebody is already doing
1573 * CANCEL.  There are the following use cases:
1574 * ldlm_cancel_resource_local(), ldlm_cancel_lru_local() and
1575 * ldlm_cli_cancel(), which check and set this flag properly. As any
1576 * attempt to cancel a lock rely on this flag, l_bl_ast list is accessed
1577 * later without any special locking.
1578 *
1579 * Calling policies for enabled LRU resize:
1580 * ----------------------------------------
1581 * flags & LDLM_CANCEL_LRUR - use LRU resize policy (SLV from server) to
1582 *			    cancel not more than \a count locks;
1583 *
1584 * flags & LDLM_CANCEL_PASSED - cancel \a count number of old locks (located at
1585 *			      the beginning of LRU list);
1586 *
1587 * flags & LDLM_CANCEL_SHRINK - cancel not more than \a count locks according to
1588 *			      memory pressure policy function;
1589 *
1590 * flags & LDLM_CANCEL_AGED - cancel \a count locks according to "aged policy".
1591 *
1592 * flags & LDLM_CANCEL_NO_WAIT - cancel as many unused locks as possible
1593 *			       (typically before replaying locks) w/o
1594 *			       sending any RPCs or waiting for any
1595 *			       outstanding RPC to complete.
1596 */
1597static int ldlm_prepare_lru_list(struct ldlm_namespace *ns, struct list_head *cancels,
1598				 int count, int max, int flags)
1599{
1600	ldlm_cancel_lru_policy_t pf;
1601	struct ldlm_lock *lock, *next;
1602	int added = 0, unused, remained;
1603
1604	spin_lock(&ns->ns_lock);
1605	unused = ns->ns_nr_unused;
1606	remained = unused;
1607
1608	if (!ns_connect_lru_resize(ns))
1609		count += unused - ns->ns_max_unused;
1610
1611	pf = ldlm_cancel_lru_policy(ns, flags);
1612	LASSERT(pf != NULL);
1613
1614	while (!list_empty(&ns->ns_unused_list)) {
1615		ldlm_policy_res_t result;
1616
1617		/* all unused locks */
1618		if (remained-- <= 0)
1619			break;
1620
1621		/* For any flags, stop scanning if @max is reached. */
1622		if (max && added >= max)
1623			break;
1624
1625		list_for_each_entry_safe(lock, next, &ns->ns_unused_list,
1626					     l_lru) {
1627			/* No locks which got blocking requests. */
1628			LASSERT(!(lock->l_flags & LDLM_FL_BL_AST));
1629
1630			if (flags & LDLM_CANCEL_NO_WAIT &&
1631			    lock->l_flags & LDLM_FL_SKIPPED)
1632				/* already processed */
1633				continue;
1634
1635			/* Somebody is already doing CANCEL. No need for this
1636			 * lock in LRU, do not traverse it again. */
1637			if (!(lock->l_flags & LDLM_FL_CANCELING))
1638				break;
1639
1640			ldlm_lock_remove_from_lru_nolock(lock);
1641		}
1642		if (&lock->l_lru == &ns->ns_unused_list)
1643			break;
1644
1645		LDLM_LOCK_GET(lock);
1646		spin_unlock(&ns->ns_lock);
1647		lu_ref_add(&lock->l_reference, __func__, current);
1648
1649		/* Pass the lock through the policy filter and see if it
1650		 * should stay in LRU.
1651		 *
1652		 * Even for shrinker policy we stop scanning if
1653		 * we find a lock that should stay in the cache.
1654		 * We should take into account lock age anyway
1655		 * as a new lock is a valuable resource even if
1656		 * it has a low weight.
1657		 *
1658		 * That is, for shrinker policy we drop only
1659		 * old locks, but additionally choose them by
1660		 * their weight. Big extent locks will stay in
1661		 * the cache. */
1662		result = pf(ns, lock, unused, added, count);
1663		if (result == LDLM_POLICY_KEEP_LOCK) {
1664			lu_ref_del(&lock->l_reference,
1665				   __func__, current);
1666			LDLM_LOCK_RELEASE(lock);
1667			spin_lock(&ns->ns_lock);
1668			break;
1669		}
1670		if (result == LDLM_POLICY_SKIP_LOCK) {
1671			lu_ref_del(&lock->l_reference,
1672				   __func__, current);
1673			LDLM_LOCK_RELEASE(lock);
1674			spin_lock(&ns->ns_lock);
1675			continue;
1676		}
1677
1678		lock_res_and_lock(lock);
1679		/* Check flags again under the lock. */
1680		if ((lock->l_flags & LDLM_FL_CANCELING) ||
1681		    (ldlm_lock_remove_from_lru(lock) == 0)) {
1682			/* Another thread is removing lock from LRU, or
1683			 * somebody is already doing CANCEL, or there
1684			 * is a blocking request which will send cancel
1685			 * by itself, or the lock is no longer unused. */
1686			unlock_res_and_lock(lock);
1687			lu_ref_del(&lock->l_reference,
1688				   __func__, current);
1689			LDLM_LOCK_RELEASE(lock);
1690			spin_lock(&ns->ns_lock);
1691			continue;
1692		}
1693		LASSERT(!lock->l_readers && !lock->l_writers);
1694
1695		/* If we have chosen to cancel this lock voluntarily, we
1696		 * better send cancel notification to server, so that it
1697		 * frees appropriate state. This might lead to a race
1698		 * where while we are doing cancel here, server is also
1699		 * silently cancelling this lock. */
1700		lock->l_flags &= ~LDLM_FL_CANCEL_ON_BLOCK;
1701
1702		/* Setting the CBPENDING flag is a little misleading,
1703		 * but prevents an important race; namely, once
1704		 * CBPENDING is set, the lock can accumulate no more
1705		 * readers/writers. Since readers and writers are
1706		 * already zero here, ldlm_lock_decref() won't see
1707		 * this flag and call l_blocking_ast */
1708		lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING;
1709
1710		/* We can't re-add to l_lru as it confuses the
1711		 * refcounting in ldlm_lock_remove_from_lru() if an AST
1712		 * arrives after we drop lr_lock below. We use l_bl_ast
1713		 * and can't use l_pending_chain as it is used both on
1714		 * server and client nevertheless bug 5666 says it is
1715		 * used only on server */
1716		LASSERT(list_empty(&lock->l_bl_ast));
1717		list_add(&lock->l_bl_ast, cancels);
1718		unlock_res_and_lock(lock);
1719		lu_ref_del(&lock->l_reference, __func__, current);
1720		spin_lock(&ns->ns_lock);
1721		added++;
1722		unused--;
1723	}
1724	spin_unlock(&ns->ns_lock);
1725	return added;
1726}
1727
1728int ldlm_cancel_lru_local(struct ldlm_namespace *ns, struct list_head *cancels,
1729			  int count, int max, ldlm_cancel_flags_t cancel_flags,
1730			  int flags)
1731{
1732	int added;
1733	added = ldlm_prepare_lru_list(ns, cancels, count, max, flags);
1734	if (added <= 0)
1735		return added;
1736	return ldlm_cli_cancel_list_local(cancels, added, cancel_flags);
1737}
1738
1739/**
1740 * Cancel at least \a nr locks from given namespace LRU.
1741 *
1742 * When called with LCF_ASYNC the blocking callback will be handled
1743 * in a thread and this function will return after the thread has been
1744 * asked to call the callback.  When called with LCF_ASYNC the blocking
1745 * callback will be performed in this function.
1746 */
1747int ldlm_cancel_lru(struct ldlm_namespace *ns, int nr,
1748		    ldlm_cancel_flags_t cancel_flags,
1749		    int flags)
1750{
1751	LIST_HEAD(cancels);
1752	int count, rc;
1753
1754	/* Just prepare the list of locks, do not actually cancel them yet.
1755	 * Locks are cancelled later in a separate thread. */
1756	count = ldlm_prepare_lru_list(ns, &cancels, nr, 0, flags);
1757	rc = ldlm_bl_to_thread_list(ns, NULL, &cancels, count, cancel_flags);
1758	if (rc == 0)
1759		return count;
1760
1761	return 0;
1762}
1763
1764/**
1765 * Find and cancel locally unused locks found on resource, matched to the
1766 * given policy, mode. GET the found locks and add them into the \a cancels
1767 * list.
1768 */
1769int ldlm_cancel_resource_local(struct ldlm_resource *res,
1770			       struct list_head *cancels,
1771			       ldlm_policy_data_t *policy,
1772			       ldlm_mode_t mode, __u64 lock_flags,
1773			       ldlm_cancel_flags_t cancel_flags, void *opaque)
1774{
1775	struct ldlm_lock *lock;
1776	int count = 0;
1777
1778	lock_res(res);
1779	list_for_each_entry(lock, &res->lr_granted, l_res_link) {
1780		if (opaque != NULL && lock->l_ast_data != opaque) {
1781			LDLM_ERROR(lock, "data %p doesn't match opaque %p",
1782				   lock->l_ast_data, opaque);
1783			//LBUG();
1784			continue;
1785		}
1786
1787		if (lock->l_readers || lock->l_writers)
1788			continue;
1789
1790		/* If somebody is already doing CANCEL, or blocking AST came,
1791		 * skip this lock. */
1792		if (lock->l_flags & LDLM_FL_BL_AST ||
1793		    lock->l_flags & LDLM_FL_CANCELING)
1794			continue;
1795
1796		if (lockmode_compat(lock->l_granted_mode, mode))
1797			continue;
1798
1799		/* If policy is given and this is IBITS lock, add to list only
1800		 * those locks that match by policy. */
1801		if (policy && (lock->l_resource->lr_type == LDLM_IBITS) &&
1802		    !(lock->l_policy_data.l_inodebits.bits &
1803		      policy->l_inodebits.bits))
1804			continue;
1805
1806		/* See CBPENDING comment in ldlm_cancel_lru */
1807		lock->l_flags |= LDLM_FL_CBPENDING | LDLM_FL_CANCELING |
1808				 lock_flags;
1809
1810		LASSERT(list_empty(&lock->l_bl_ast));
1811		list_add(&lock->l_bl_ast, cancels);
1812		LDLM_LOCK_GET(lock);
1813		count++;
1814	}
1815	unlock_res(res);
1816
1817	return ldlm_cli_cancel_list_local(cancels, count, cancel_flags);
1818}
1819EXPORT_SYMBOL(ldlm_cancel_resource_local);
1820
1821/**
1822 * Cancel client-side locks from a list and send/prepare cancel RPCs to the
1823 * server.
1824 * If \a req is NULL, send CANCEL request to server with handles of locks
1825 * in the \a cancels. If EARLY_CANCEL is not supported, send CANCEL requests
1826 * separately per lock.
1827 * If \a req is not NULL, put handles of locks in \a cancels into the request
1828 * buffer at the offset \a off.
1829 * Destroy \a cancels at the end.
1830 */
1831int ldlm_cli_cancel_list(struct list_head *cancels, int count,
1832			 struct ptlrpc_request *req, ldlm_cancel_flags_t flags)
1833{
1834	struct ldlm_lock *lock;
1835	int res = 0;
1836
1837	if (list_empty(cancels) || count == 0)
1838		return 0;
1839
1840	/* XXX: requests (both batched and not) could be sent in parallel.
1841	 * Usually it is enough to have just 1 RPC, but it is possible that
1842	 * there are too many locks to be cancelled in LRU or on a resource.
1843	 * It would also speed up the case when the server does not support
1844	 * the feature. */
1845	while (count > 0) {
1846		LASSERT(!list_empty(cancels));
1847		lock = list_entry(cancels->next, struct ldlm_lock,
1848				      l_bl_ast);
1849		LASSERT(lock->l_conn_export);
1850
1851		if (exp_connect_cancelset(lock->l_conn_export)) {
1852			res = count;
1853			if (req)
1854				ldlm_cancel_pack(req, cancels, count);
1855			else
1856				res = ldlm_cli_cancel_req(lock->l_conn_export,
1857							  cancels, count,
1858							  flags);
1859		} else {
1860			res = ldlm_cli_cancel_req(lock->l_conn_export,
1861						  cancels, 1, flags);
1862		}
1863
1864		if (res < 0) {
1865			CDEBUG_LIMIT(res == -ESHUTDOWN ? D_DLMTRACE : D_ERROR,
1866				     "ldlm_cli_cancel_list: %d\n", res);
1867			res = count;
1868		}
1869
1870		count -= res;
1871		ldlm_lock_list_put(cancels, l_bl_ast, res);
1872	}
1873	LASSERT(count == 0);
1874	return 0;
1875}
1876EXPORT_SYMBOL(ldlm_cli_cancel_list);
1877
1878/**
1879 * Cancel all locks on a resource that have 0 readers/writers.
1880 *
1881 * If flags & LDLM_FL_LOCAL_ONLY, throw the locks away without trying
1882 * to notify the server. */
1883int ldlm_cli_cancel_unused_resource(struct ldlm_namespace *ns,
1884				    const struct ldlm_res_id *res_id,
1885				    ldlm_policy_data_t *policy,
1886				    ldlm_mode_t mode,
1887				    ldlm_cancel_flags_t flags,
1888				    void *opaque)
1889{
1890	struct ldlm_resource *res;
1891	LIST_HEAD(cancels);
1892	int count;
1893	int rc;
1894
1895	res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
1896	if (res == NULL) {
1897		/* This is not a problem. */
1898		CDEBUG(D_INFO, "No resource %llu\n", res_id->name[0]);
1899		return 0;
1900	}
1901
1902	LDLM_RESOURCE_ADDREF(res);
1903	count = ldlm_cancel_resource_local(res, &cancels, policy, mode,
1904					   0, flags | LCF_BL_AST, opaque);
1905	rc = ldlm_cli_cancel_list(&cancels, count, NULL, flags);
1906	if (rc != ELDLM_OK)
1907		CERROR("canceling unused lock "DLDLMRES": rc = %d\n",
1908		       PLDLMRES(res), rc);
1909
1910	LDLM_RESOURCE_DELREF(res);
1911	ldlm_resource_putref(res);
1912	return 0;
1913}
1914EXPORT_SYMBOL(ldlm_cli_cancel_unused_resource);
1915
1916struct ldlm_cli_cancel_arg {
1917	int     lc_flags;
1918	void   *lc_opaque;
1919};
1920
1921static int ldlm_cli_hash_cancel_unused(struct cfs_hash *hs, struct cfs_hash_bd *bd,
1922				       struct hlist_node *hnode, void *arg)
1923{
1924	struct ldlm_resource	   *res = cfs_hash_object(hs, hnode);
1925	struct ldlm_cli_cancel_arg     *lc = arg;
1926
1927	ldlm_cli_cancel_unused_resource(ldlm_res_to_ns(res), &res->lr_name,
1928					NULL, LCK_MINMODE,
1929					lc->lc_flags, lc->lc_opaque);
1930	/* must return 0 for hash iteration */
1931	return 0;
1932}
1933
1934/**
1935 * Cancel all locks on a namespace (or a specific resource, if given)
1936 * that have 0 readers/writers.
1937 *
1938 * If flags & LCF_LOCAL, throw the locks away without trying
1939 * to notify the server. */
1940int ldlm_cli_cancel_unused(struct ldlm_namespace *ns,
1941			   const struct ldlm_res_id *res_id,
1942			   ldlm_cancel_flags_t flags, void *opaque)
1943{
1944	struct ldlm_cli_cancel_arg arg = {
1945		.lc_flags       = flags,
1946		.lc_opaque      = opaque,
1947	};
1948
1949	if (ns == NULL)
1950		return ELDLM_OK;
1951
1952	if (res_id != NULL) {
1953		return ldlm_cli_cancel_unused_resource(ns, res_id, NULL,
1954						       LCK_MINMODE, flags,
1955						       opaque);
1956	} else {
1957		cfs_hash_for_each_nolock(ns->ns_rs_hash,
1958					 ldlm_cli_hash_cancel_unused, &arg);
1959		return ELDLM_OK;
1960	}
1961}
1962EXPORT_SYMBOL(ldlm_cli_cancel_unused);
1963
1964/* Lock iterators. */
1965
1966int ldlm_resource_foreach(struct ldlm_resource *res, ldlm_iterator_t iter,
1967			  void *closure)
1968{
1969	struct list_head *tmp, *next;
1970	struct ldlm_lock *lock;
1971	int rc = LDLM_ITER_CONTINUE;
1972
1973	if (!res)
1974		return LDLM_ITER_CONTINUE;
1975
1976	lock_res(res);
1977	list_for_each_safe(tmp, next, &res->lr_granted) {
1978		lock = list_entry(tmp, struct ldlm_lock, l_res_link);
1979
1980		if (iter(lock, closure) == LDLM_ITER_STOP) {
1981			rc = LDLM_ITER_STOP;
1982			goto out;
1983		}
1984	}
1985
1986	list_for_each_safe(tmp, next, &res->lr_converting) {
1987		lock = list_entry(tmp, struct ldlm_lock, l_res_link);
1988
1989		if (iter(lock, closure) == LDLM_ITER_STOP) {
1990			rc = LDLM_ITER_STOP;
1991			goto out;
1992		}
1993	}
1994
1995	list_for_each_safe(tmp, next, &res->lr_waiting) {
1996		lock = list_entry(tmp, struct ldlm_lock, l_res_link);
1997
1998		if (iter(lock, closure) == LDLM_ITER_STOP) {
1999			rc = LDLM_ITER_STOP;
2000			goto out;
2001		}
2002	}
2003 out:
2004	unlock_res(res);
2005	return rc;
2006}
2007EXPORT_SYMBOL(ldlm_resource_foreach);
2008
2009struct iter_helper_data {
2010	ldlm_iterator_t iter;
2011	void *closure;
2012};
2013
2014static int ldlm_iter_helper(struct ldlm_lock *lock, void *closure)
2015{
2016	struct iter_helper_data *helper = closure;
2017	return helper->iter(lock, helper->closure);
2018}
2019
2020static int ldlm_res_iter_helper(struct cfs_hash *hs, struct cfs_hash_bd *bd,
2021				struct hlist_node *hnode, void *arg)
2022
2023{
2024	struct ldlm_resource *res = cfs_hash_object(hs, hnode);
2025
2026	return ldlm_resource_foreach(res, ldlm_iter_helper, arg) ==
2027	       LDLM_ITER_STOP;
2028}
2029
2030void ldlm_namespace_foreach(struct ldlm_namespace *ns,
2031			    ldlm_iterator_t iter, void *closure)
2032
2033{
2034	struct iter_helper_data helper = {
2035		.iter		= iter,
2036		.closure	= closure,
2037	};
2038
2039	cfs_hash_for_each_nolock(ns->ns_rs_hash,
2040				 ldlm_res_iter_helper, &helper);
2041
2042}
2043EXPORT_SYMBOL(ldlm_namespace_foreach);
2044
2045/* non-blocking function to manipulate a lock whose cb_data is being put away.
2046 * return  0:  find no resource
2047 *       > 0:  must be LDLM_ITER_STOP/LDLM_ITER_CONTINUE.
2048 *       < 0:  errors
2049 */
2050int ldlm_resource_iterate(struct ldlm_namespace *ns,
2051			  const struct ldlm_res_id *res_id,
2052			  ldlm_iterator_t iter, void *data)
2053{
2054	struct ldlm_resource *res;
2055	int rc;
2056
2057	if (ns == NULL) {
2058		CERROR("must pass in namespace\n");
2059		LBUG();
2060	}
2061
2062	res = ldlm_resource_get(ns, NULL, res_id, 0, 0);
2063	if (res == NULL)
2064		return 0;
2065
2066	LDLM_RESOURCE_ADDREF(res);
2067	rc = ldlm_resource_foreach(res, iter, data);
2068	LDLM_RESOURCE_DELREF(res);
2069	ldlm_resource_putref(res);
2070	return rc;
2071}
2072EXPORT_SYMBOL(ldlm_resource_iterate);
2073
2074/* Lock replay */
2075
2076static int ldlm_chain_lock_for_replay(struct ldlm_lock *lock, void *closure)
2077{
2078	struct list_head *list = closure;
2079
2080	/* we use l_pending_chain here, because it's unused on clients. */
2081	LASSERTF(list_empty(&lock->l_pending_chain),
2082		 "lock %p next %p prev %p\n",
2083		 lock, &lock->l_pending_chain.next,&lock->l_pending_chain.prev);
2084	/* bug 9573: don't replay locks left after eviction, or
2085	 * bug 17614: locks being actively cancelled. Get a reference
2086	 * on a lock so that it does not disappear under us (e.g. due to cancel)
2087	 */
2088	if (!(lock->l_flags & (LDLM_FL_FAILED|LDLM_FL_CANCELING))) {
2089		list_add(&lock->l_pending_chain, list);
2090		LDLM_LOCK_GET(lock);
2091	}
2092
2093	return LDLM_ITER_CONTINUE;
2094}
2095
2096static int replay_lock_interpret(const struct lu_env *env,
2097				 struct ptlrpc_request *req,
2098				 struct ldlm_async_args *aa, int rc)
2099{
2100	struct ldlm_lock     *lock;
2101	struct ldlm_reply    *reply;
2102	struct obd_export    *exp;
2103
2104	atomic_dec(&req->rq_import->imp_replay_inflight);
2105	if (rc != ELDLM_OK)
2106		goto out;
2107
2108
2109	reply = req_capsule_server_get(&req->rq_pill, &RMF_DLM_REP);
2110	if (reply == NULL) {
2111		rc = -EPROTO;
2112		goto out;
2113	}
2114
2115	lock = ldlm_handle2lock(&aa->lock_handle);
2116	if (!lock) {
2117		CERROR("received replay ack for unknown local cookie %#llx"
2118		       " remote cookie %#llx from server %s id %s\n",
2119		       aa->lock_handle.cookie, reply->lock_handle.cookie,
2120		       req->rq_export->exp_client_uuid.uuid,
2121		       libcfs_id2str(req->rq_peer));
2122		rc = -ESTALE;
2123		goto out;
2124	}
2125
2126	/* Key change rehash lock in per-export hash with new key */
2127	exp = req->rq_export;
2128	if (exp && exp->exp_lock_hash) {
2129		/* In the function below, .hs_keycmp resolves to
2130		 * ldlm_export_lock_keycmp() */
2131		/* coverity[overrun-buffer-val] */
2132		cfs_hash_rehash_key(exp->exp_lock_hash,
2133				    &lock->l_remote_handle,
2134				    &reply->lock_handle,
2135				    &lock->l_exp_hash);
2136	} else {
2137		lock->l_remote_handle = reply->lock_handle;
2138	}
2139
2140	LDLM_DEBUG(lock, "replayed lock:");
2141	ptlrpc_import_recovery_state_machine(req->rq_import);
2142	LDLM_LOCK_PUT(lock);
2143out:
2144	if (rc != ELDLM_OK)
2145		ptlrpc_connect_import(req->rq_import);
2146
2147	return rc;
2148}
2149
2150static int replay_one_lock(struct obd_import *imp, struct ldlm_lock *lock)
2151{
2152	struct ptlrpc_request *req;
2153	struct ldlm_async_args *aa;
2154	struct ldlm_request   *body;
2155	int flags;
2156
2157	/* Bug 11974: Do not replay a lock which is actively being canceled */
2158	if (lock->l_flags & LDLM_FL_CANCELING) {
2159		LDLM_DEBUG(lock, "Not replaying canceled lock:");
2160		return 0;
2161	}
2162
2163	/* If this is reply-less callback lock, we cannot replay it, since
2164	 * server might have long dropped it, but notification of that event was
2165	 * lost by network. (and server granted conflicting lock already) */
2166	if (lock->l_flags & LDLM_FL_CANCEL_ON_BLOCK) {
2167		LDLM_DEBUG(lock, "Not replaying reply-less lock:");
2168		ldlm_lock_cancel(lock);
2169		return 0;
2170	}
2171
2172	/*
2173	 * If granted mode matches the requested mode, this lock is granted.
2174	 *
2175	 * If they differ, but we have a granted mode, then we were granted
2176	 * one mode and now want another: ergo, converting.
2177	 *
2178	 * If we haven't been granted anything and are on a resource list,
2179	 * then we're blocked/waiting.
2180	 *
2181	 * If we haven't been granted anything and we're NOT on a resource list,
2182	 * then we haven't got a reply yet and don't have a known disposition.
2183	 * This happens whenever a lock enqueue is the request that triggers
2184	 * recovery.
2185	 */
2186	if (lock->l_granted_mode == lock->l_req_mode)
2187		flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_GRANTED;
2188	else if (lock->l_granted_mode)
2189		flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_CONV;
2190	else if (!list_empty(&lock->l_res_link))
2191		flags = LDLM_FL_REPLAY | LDLM_FL_BLOCK_WAIT;
2192	else
2193		flags = LDLM_FL_REPLAY;
2194
2195	req = ptlrpc_request_alloc_pack(imp, &RQF_LDLM_ENQUEUE,
2196					LUSTRE_DLM_VERSION, LDLM_ENQUEUE);
2197	if (req == NULL)
2198		return -ENOMEM;
2199
2200	/* We're part of recovery, so don't wait for it. */
2201	req->rq_send_state = LUSTRE_IMP_REPLAY_LOCKS;
2202
2203	body = req_capsule_client_get(&req->rq_pill, &RMF_DLM_REQ);
2204	ldlm_lock2desc(lock, &body->lock_desc);
2205	body->lock_flags = ldlm_flags_to_wire(flags);
2206
2207	ldlm_lock2handle(lock, &body->lock_handle[0]);
2208	if (lock->l_lvb_len > 0)
2209		req_capsule_extend(&req->rq_pill, &RQF_LDLM_ENQUEUE_LVB);
2210	req_capsule_set_size(&req->rq_pill, &RMF_DLM_LVB, RCL_SERVER,
2211			     lock->l_lvb_len);
2212	ptlrpc_request_set_replen(req);
2213	/* notify the server we've replayed all requests.
2214	 * also, we mark the request to be put on a dedicated
2215	 * queue to be processed after all request replayes.
2216	 * bug 6063 */
2217	lustre_msg_set_flags(req->rq_reqmsg, MSG_REQ_REPLAY_DONE);
2218
2219	LDLM_DEBUG(lock, "replaying lock:");
2220
2221	atomic_inc(&req->rq_import->imp_replay_inflight);
2222	CLASSERT(sizeof(*aa) <= sizeof(req->rq_async_args));
2223	aa = ptlrpc_req_async_args(req);
2224	aa->lock_handle = body->lock_handle[0];
2225	req->rq_interpret_reply = (ptlrpc_interpterer_t)replay_lock_interpret;
2226	ptlrpcd_add_req(req, PDL_POLICY_LOCAL, -1);
2227
2228	return 0;
2229}
2230
2231/**
2232 * Cancel as many unused locks as possible before replay. since we are
2233 * in recovery, we can't wait for any outstanding RPCs to send any RPC
2234 * to the server.
2235 *
2236 * Called only in recovery before replaying locks. there is no need to
2237 * replay locks that are unused. since the clients may hold thousands of
2238 * cached unused locks, dropping the unused locks can greatly reduce the
2239 * load on the servers at recovery time.
2240 */
2241static void ldlm_cancel_unused_locks_for_replay(struct ldlm_namespace *ns)
2242{
2243	int canceled;
2244	LIST_HEAD(cancels);
2245
2246	CDEBUG(D_DLMTRACE, "Dropping as many unused locks as possible before"
2247			   "replay for namespace %s (%d)\n",
2248			   ldlm_ns_name(ns), ns->ns_nr_unused);
2249
2250	/* We don't need to care whether or not LRU resize is enabled
2251	 * because the LDLM_CANCEL_NO_WAIT policy doesn't use the
2252	 * count parameter */
2253	canceled = ldlm_cancel_lru_local(ns, &cancels, ns->ns_nr_unused, 0,
2254					 LCF_LOCAL, LDLM_CANCEL_NO_WAIT);
2255
2256	CDEBUG(D_DLMTRACE, "Canceled %d unused locks from namespace %s\n",
2257			   canceled, ldlm_ns_name(ns));
2258}
2259
2260int ldlm_replay_locks(struct obd_import *imp)
2261{
2262	struct ldlm_namespace *ns = imp->imp_obd->obd_namespace;
2263	LIST_HEAD(list);
2264	struct ldlm_lock *lock, *next;
2265	int rc = 0;
2266
2267	LASSERT(atomic_read(&imp->imp_replay_inflight) == 0);
2268
2269	/* don't replay locks if import failed recovery */
2270	if (imp->imp_vbr_failed)
2271		return 0;
2272
2273	/* ensure this doesn't fall to 0 before all have been queued */
2274	atomic_inc(&imp->imp_replay_inflight);
2275
2276	if (ldlm_cancel_unused_locks_before_replay)
2277		ldlm_cancel_unused_locks_for_replay(ns);
2278
2279	ldlm_namespace_foreach(ns, ldlm_chain_lock_for_replay, &list);
2280
2281	list_for_each_entry_safe(lock, next, &list, l_pending_chain) {
2282		list_del_init(&lock->l_pending_chain);
2283		if (rc) {
2284			LDLM_LOCK_RELEASE(lock);
2285			continue; /* or try to do the rest? */
2286		}
2287		rc = replay_one_lock(imp, lock);
2288		LDLM_LOCK_RELEASE(lock);
2289	}
2290
2291	atomic_dec(&imp->imp_replay_inflight);
2292
2293	return rc;
2294}
2295EXPORT_SYMBOL(ldlm_replay_locks);
2296