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[fs/lustre-release.git] / lustre / osc / osc_cache.c
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.gnu.org/licenses/gpl-2.0.html
19  *
20  * GPL HEADER END
21  */
22 /*
23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2012, 2017, Intel Corporation.
27  *
28  */
29 /*
30  * This file is part of Lustre, http://www.lustre.org/
31  *
32  * osc cache management.
33  *
34  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
35  */
36
37 #define DEBUG_SUBSYSTEM S_OSC
38
39 #include <lustre_osc.h>
40 #include <lustre_dlm.h>
41
42 #include "osc_internal.h"
43
44 static int extent_debug; /* set it to be true for more debug */
45
46 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
47 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
48                            enum osc_extent_state state);
49 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
50                               struct osc_async_page *oap, int sent, int rc);
51 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
52                           int cmd);
53 static int osc_refresh_count(const struct lu_env *env,
54                              struct osc_async_page *oap, int cmd);
55 static int osc_io_unplug_async(const struct lu_env *env,
56                                struct client_obd *cli, struct osc_object *osc);
57 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
58                            unsigned int lost_grant, unsigned int dirty_grant);
59
60 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
61                                   const char *func, int line);
62 #define osc_extent_tree_dump(mask, obj) \
63         osc_extent_tree_dump0(mask, obj, __func__, __LINE__)
64
65 static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
66                                 unsigned int unused);
67
68 /** \addtogroup osc
69  *  @{
70  */
71
72 /* ------------------ osc extent ------------------ */
73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
74 {
75         char *buf = flags;
76         *buf++ = ext->oe_rw ? 'r' : 'w';
77         if (!RB_EMPTY_NODE(&ext->oe_node))
78                 *buf++ = 'i';
79         if (ext->oe_sync)
80                 *buf++ = 'S';
81         if (ext->oe_srvlock)
82                 *buf++ = 's';
83         if (ext->oe_hp)
84                 *buf++ = 'h';
85         if (ext->oe_urgent)
86                 *buf++ = 'u';
87         if (ext->oe_memalloc)
88                 *buf++ = 'm';
89         if (ext->oe_trunc_pending)
90                 *buf++ = 't';
91         if (ext->oe_fsync_wait)
92                 *buf++ = 'Y';
93         *buf = 0;
94         return flags;
95 }
96
97 #define EXTSTR       "[%lu -> %lu/%lu]"
98 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
99 static const char *const oes_strings[] = {
100         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
101
102 #define OSC_EXTENT_DUMP_WITH_LOC(file, func, line, mask, extent, fmt, ...) do {\
103         static struct cfs_debug_limit_state cdls;                             \
104         struct osc_extent *__ext = (extent);                                  \
105         char __buf[16];                                                       \
106                                                                               \
107         __CDEBUG_WITH_LOC(file, func, line, mask, &cdls,                      \
108                 "extent %p@{" EXTSTR ", "                                     \
109                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
110                 /* ----- extent part 0 ----- */                               \
111                 __ext, EXTPARA(__ext),                                        \
112                 /* ----- part 1 ----- */                                      \
113                 kref_read(&__ext->oe_refc),                                   \
114                 atomic_read(&__ext->oe_users),                                \
115                 list_empty_marker(&__ext->oe_link),                           \
116                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
117                 __ext->oe_obj,                                                \
118                 /* ----- part 2 ----- */                                      \
119                 __ext->oe_grants, __ext->oe_nr_pages,                         \
120                 list_empty_marker(&__ext->oe_pages),                          \
121                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
122                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
123                 /* ----- part 4 ----- */                                      \
124                 ## __VA_ARGS__);                                              \
125         if (mask == D_ERROR && __ext->oe_dlmlock != NULL)                     \
126                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
127         else                                                                  \
128                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
129 } while (0)
130
131 #define OSC_EXTENT_DUMP(mask, ext, fmt, ...)                            \
132         OSC_EXTENT_DUMP_WITH_LOC(__FILE__, __func__, __LINE__,          \
133                                  mask, ext, fmt, ## __VA_ARGS__)
134
135 #undef EASSERTF
136 #define EASSERTF(expr, ext, fmt, args...) do {                          \
137         if (!(expr)) {                                                  \
138                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
139                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
140                 LASSERT(expr);                                          \
141         }                                                               \
142 } while (0)
143
144 #undef EASSERT
145 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
146
147 static inline struct osc_extent *rb_extent(struct rb_node *n)
148 {
149         return rb_entry_safe(n, struct osc_extent, oe_node);
150 }
151
152 static inline struct osc_extent *next_extent(struct osc_extent *ext)
153 {
154         if (ext == NULL)
155                 return NULL;
156
157         LASSERT(!RB_EMPTY_NODE(&ext->oe_node));
158         return rb_extent(rb_next(&ext->oe_node));
159 }
160
161 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
162 {
163         if (ext == NULL)
164                 return NULL;
165
166         LASSERT(!RB_EMPTY_NODE(&ext->oe_node));
167         return rb_extent(rb_prev(&ext->oe_node));
168 }
169
170 static inline struct osc_extent *first_extent(struct osc_object *obj)
171 {
172         return rb_extent(rb_first(&obj->oo_root));
173 }
174
175 /* object must be locked by caller. */
176 static int osc_extent_sanity_check0(struct osc_extent *ext,
177                                     const char *func, const int line)
178 {
179         struct osc_object *obj = ext->oe_obj;
180         struct osc_async_page *oap;
181         size_t page_count;
182         int rc = 0;
183
184         assert_osc_object_is_locked(obj);
185
186         if (ext->oe_state >= OES_STATE_MAX)
187                 GOTO(out, rc = 10);
188
189         if (kref_read(&ext->oe_refc) <= 0)
190                 GOTO(out, rc = 20);
191
192         if (kref_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
193                 GOTO(out, rc = 30);
194
195         switch (ext->oe_state) {
196         case OES_INV:
197                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
198                         GOTO(out, rc = 35);
199                 GOTO(out, rc = 0);
200                 break;
201         case OES_ACTIVE:
202                 if (atomic_read(&ext->oe_users) == 0)
203                         GOTO(out, rc = 40);
204                 if (ext->oe_hp)
205                         GOTO(out, rc = 50);
206                 if (ext->oe_fsync_wait && !ext->oe_urgent)
207                         GOTO(out, rc = 55);
208                 break;
209         case OES_CACHE:
210                 if (ext->oe_grants == 0)
211                         GOTO(out, rc = 60);
212                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
213                         GOTO(out, rc = 65);
214                 /* fallthrough */
215         default:
216                 if (atomic_read(&ext->oe_users) > 0)
217                         GOTO(out, rc = 70);
218         }
219
220         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
221                 GOTO(out, rc = 80);
222
223         if (ext->oe_sync && ext->oe_grants > 0)
224                 GOTO(out, rc = 90);
225
226         if (ext->oe_dlmlock != NULL &&
227             ext->oe_dlmlock->l_resource->lr_type == LDLM_EXTENT &&
228             !ldlm_is_failed(ext->oe_dlmlock)) {
229                 struct ldlm_extent *extent;
230
231                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
232                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
233                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
234                         GOTO(out, rc = 100);
235
236                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
237                         GOTO(out, rc = 102);
238         }
239
240         if (ext->oe_nr_pages > ext->oe_mppr)
241                 GOTO(out, rc = 105);
242
243         /* Do not verify page list if extent is in RPC. This is because an
244          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
245         if (ext->oe_state > OES_CACHE)
246                 GOTO(out, rc = 0);
247
248         if (!extent_debug)
249                 GOTO(out, rc = 0);
250
251         page_count = 0;
252         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
253                 pgoff_t index = osc_index(oap2osc(oap));
254                 ++page_count;
255                 if (index > ext->oe_end || index < ext->oe_start)
256                         GOTO(out, rc = 110);
257         }
258         if (page_count != ext->oe_nr_pages)
259                 GOTO(out, rc = 120);
260
261 out:
262         if (rc != 0)
263                 OSC_EXTENT_DUMP_WITH_LOC(__FILE__, func, line, D_ERROR, ext,
264                                          "sanity check %p failed: rc = %d\n",
265                                          ext, rc);
266         return rc;
267 }
268
269 #define sanity_check_nolock(ext) \
270         osc_extent_sanity_check0(ext, __func__, __LINE__)
271
272 #define sanity_check(ext) ({                                                   \
273         int __res;                                                             \
274         osc_object_lock((ext)->oe_obj);                                        \
275         __res = sanity_check_nolock(ext);                                      \
276         osc_object_unlock((ext)->oe_obj);                                      \
277         __res;                                                                 \
278 })
279
280 static inline bool
281 overlapped(const struct osc_extent *ex1, const struct osc_extent *ex2)
282 {
283         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
284 }
285
286 /**
287  * sanity check - to make sure there is no overlapped extent in the tree.
288  */
289 static int osc_extent_is_overlapped(struct osc_object *obj,
290                                     struct osc_extent *ext)
291 {
292         struct osc_extent *tmp;
293
294         assert_osc_object_is_locked(obj);
295
296         if (!extent_debug)
297                 return 0;
298
299         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
300                 if (tmp == ext)
301                         continue;
302                 if (overlapped(tmp, ext))
303                         return 1;
304         }
305         return 0;
306 }
307
308 static void osc_extent_state_set(struct osc_extent *ext, int state)
309 {
310         assert_osc_object_is_locked(ext->oe_obj);
311         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
312
313         /* Never try to sanity check a state changing extent :-) */
314         /* LASSERT(sanity_check_nolock(ext) == 0); */
315
316         /* TODO: validate the state machine */
317         smp_store_release(&ext->oe_state, state);
318         wake_up(&ext->oe_waitq);
319 }
320
321 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
322 {
323         struct osc_extent *ext;
324
325         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
326         if (ext == NULL)
327                 return NULL;
328
329         RB_CLEAR_NODE(&ext->oe_node);
330         ext->oe_obj = obj;
331         cl_object_get(osc2cl(obj));
332         kref_init(&ext->oe_refc);
333         atomic_set(&ext->oe_users, 0);
334         INIT_LIST_HEAD(&ext->oe_link);
335         ext->oe_state = OES_INV;
336         INIT_LIST_HEAD(&ext->oe_pages);
337         init_waitqueue_head(&ext->oe_waitq);
338         ext->oe_dlmlock = NULL;
339
340         return ext;
341 }
342
343 static void osc_extent_free(struct kref *kref)
344 {
345         struct osc_extent *ext = container_of(kref, struct osc_extent,
346                                               oe_refc);
347
348         LASSERT(list_empty(&ext->oe_link));
349         LASSERT(atomic_read(&ext->oe_users) == 0);
350         LASSERT(ext->oe_state == OES_INV);
351         LASSERT(RB_EMPTY_NODE(&ext->oe_node));
352
353         if (ext->oe_dlmlock) {
354                 lu_ref_del(&ext->oe_dlmlock->l_reference,
355                            "osc_extent", ext);
356                 LDLM_LOCK_PUT(ext->oe_dlmlock);
357                 ext->oe_dlmlock = NULL;
358         }
359 #if 0
360         /* If/When cl_object_put drops the need for 'env',
361          * this code can be enabled, and matching code in
362          * osc_extent_put removed.
363          */
364         cl_object_put(osc2cl(ext->oe_obj));
365
366         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
367 #endif
368 }
369
370 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
371 {
372         LASSERT(kref_read(&ext->oe_refc) >= 0);
373         kref_get(&ext->oe_refc);
374         return ext;
375 }
376
377 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
378 {
379         LASSERT(kref_read(&ext->oe_refc) > 0);
380         if (kref_put(&ext->oe_refc, osc_extent_free)) {
381                 /* This should be in osc_extent_free(), but
382                  * while we need to pass 'env' it cannot be.
383                  */
384                 cl_object_put(env, osc2cl(ext->oe_obj));
385
386                 OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
387         }
388 }
389
390 /**
391  * osc_extent_put_trust() is a special version of osc_extent_put() when
392  * it's known that the caller is not the last user. This is to address the
393  * problem of lacking of lu_env ;-).
394  */
395 static void osc_extent_put_trust(struct osc_extent *ext)
396 {
397         LASSERT(kref_read(&ext->oe_refc) > 1);
398         assert_osc_object_is_locked(ext->oe_obj);
399         osc_extent_put(NULL, ext);
400 }
401
402 /**
403  * Return the extent which includes pgoff @index, or return the greatest
404  * previous extent in the tree.
405  */
406 static struct osc_extent *osc_extent_search(struct osc_object *obj,
407                                             pgoff_t index)
408 {
409         struct rb_node    *n = obj->oo_root.rb_node;
410         struct osc_extent *tmp, *p = NULL;
411
412         assert_osc_object_is_locked(obj);
413         while (n != NULL) {
414                 tmp = rb_extent(n);
415                 if (index < tmp->oe_start) {
416                         n = n->rb_left;
417                 } else if (index > tmp->oe_end) {
418                         p = rb_extent(n);
419                         n = n->rb_right;
420                 } else {
421                         return tmp;
422                 }
423         }
424         return p;
425 }
426
427 /*
428  * Return the extent covering @index, otherwise return NULL.
429  * caller must have held object lock.
430  */
431 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
432                                             pgoff_t index)
433 {
434         struct osc_extent *ext;
435
436         ext = osc_extent_search(obj, index);
437         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
438                 return osc_extent_get(ext);
439         return NULL;
440 }
441
442 /* caller must have held object lock. */
443 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
444 {
445         struct rb_node   **n      = &obj->oo_root.rb_node;
446         struct rb_node    *parent = NULL;
447         struct osc_extent *tmp;
448
449         LASSERT(RB_EMPTY_NODE(&ext->oe_node));
450         LASSERT(ext->oe_obj == obj);
451         assert_osc_object_is_locked(obj);
452         while (*n != NULL) {
453                 tmp = rb_extent(*n);
454                 parent = *n;
455
456                 if (ext->oe_end < tmp->oe_start)
457                         n = &(*n)->rb_left;
458                 else if (ext->oe_start > tmp->oe_end)
459                         n = &(*n)->rb_right;
460                 else
461                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
462         }
463         rb_link_node(&ext->oe_node, parent, n);
464         rb_insert_color(&ext->oe_node, &obj->oo_root);
465         osc_extent_get(ext);
466 }
467
468 /* caller must have held object lock. */
469 static void osc_extent_erase(struct osc_extent *ext)
470 {
471         struct osc_object *obj = ext->oe_obj;
472         assert_osc_object_is_locked(obj);
473         if (!RB_EMPTY_NODE(&ext->oe_node)) {
474                 rb_erase(&ext->oe_node, &obj->oo_root);
475                 RB_CLEAR_NODE(&ext->oe_node);
476                 /* rbtree held a refcount */
477                 osc_extent_put_trust(ext);
478         }
479 }
480
481 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
482 {
483         struct osc_object *obj = ext->oe_obj;
484
485         assert_osc_object_is_locked(obj);
486         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
487         if (ext->oe_state == OES_CACHE) {
488                 osc_extent_state_set(ext, OES_ACTIVE);
489                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
490         }
491         atomic_inc(&ext->oe_users);
492         list_del_init(&ext->oe_link);
493         return osc_extent_get(ext);
494 }
495
496 static void __osc_extent_remove(struct osc_extent *ext)
497 {
498         assert_osc_object_is_locked(ext->oe_obj);
499         LASSERT(list_empty(&ext->oe_pages));
500         osc_extent_erase(ext);
501         list_del_init(&ext->oe_link);
502         osc_extent_state_set(ext, OES_INV);
503         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
504 }
505
506 static void osc_extent_remove(struct osc_extent *ext)
507 {
508         struct osc_object *obj = ext->oe_obj;
509
510         osc_object_lock(obj);
511         __osc_extent_remove(ext);
512         osc_object_unlock(obj);
513 }
514
515 /**
516  * This function is used to merge extents to get better performance. It checks
517  * if @cur and @victim are contiguous at block level.
518  */
519 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
520                             struct osc_extent *victim)
521 {
522         struct osc_object       *obj = cur->oe_obj;
523         struct client_obd       *cli = osc_cli(obj);
524         pgoff_t                  chunk_start;
525         pgoff_t                  chunk_end;
526         int                      ppc_bits;
527
528         LASSERT(cur->oe_state == OES_CACHE);
529         assert_osc_object_is_locked(obj);
530         if (victim == NULL)
531                 return -EINVAL;
532
533         if (victim->oe_state != OES_INV &&
534             (victim->oe_state != OES_CACHE || victim->oe_fsync_wait))
535                 return -EBUSY;
536
537         if (cur->oe_max_end != victim->oe_max_end)
538                 return -ERANGE;
539
540         /*
541          * In the rare case max_pages_per_rpc (mppr) is changed, don't
542          * merge extents until after old ones have been sent, or the
543          * "extents are aligned to RPCs" checks are unhappy.
544          */
545         if (cur->oe_mppr != victim->oe_mppr)
546                 return -ERANGE;
547
548         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
549         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT;
550         chunk_start = cur->oe_start >> ppc_bits;
551         chunk_end   = cur->oe_end   >> ppc_bits;
552         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
553             chunk_end + 1 != victim->oe_start >> ppc_bits)
554                 return -ERANGE;
555
556         /* overall extent size should not exceed the max supported limit
557          * reported by the server */
558         if (cur->oe_end - cur->oe_start + 1 +
559             victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
560                 return -ERANGE;
561
562         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
563
564         cur->oe_start     = min(cur->oe_start, victim->oe_start);
565         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
566         /* per-extent tax should be accounted only once for the whole extent */
567         cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
568         cur->oe_nr_pages += victim->oe_nr_pages;
569         /* only the following bits are needed to merge */
570         cur->oe_urgent   |= victim->oe_urgent;
571         cur->oe_memalloc |= victim->oe_memalloc;
572         list_splice_init(&victim->oe_pages, &cur->oe_pages);
573         victim->oe_nr_pages = 0;
574
575         osc_extent_get(victim);
576         __osc_extent_remove(victim);
577         osc_extent_put(env, victim);
578
579         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
580         return 0;
581 }
582
583 /**
584  * Drop user count of osc_extent, and unplug IO asynchronously.
585  */
586 void osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
587 {
588         struct osc_object *obj = ext->oe_obj;
589         struct client_obd *cli = osc_cli(obj);
590         ENTRY;
591
592         LASSERT(atomic_read(&ext->oe_users) > 0);
593         LASSERT(sanity_check(ext) == 0);
594         LASSERT(ext->oe_grants > 0);
595
596         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
597                 LASSERT(ext->oe_state == OES_ACTIVE);
598                 if (ext->oe_trunc_pending) {
599                         /* a truncate process is waiting for this extent.
600                          * This may happen due to a race, check
601                          * osc_cache_truncate_start(). */
602                         osc_extent_state_set(ext, OES_TRUNC);
603                         ext->oe_trunc_pending = 0;
604                         osc_object_unlock(obj);
605                 } else {
606                         int grant = 0;
607
608                         osc_extent_state_set(ext, OES_CACHE);
609                         osc_update_pending(obj, OBD_BRW_WRITE,
610                                            ext->oe_nr_pages);
611
612                         /* try to merge the previous and next extent. */
613                         if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
614                                 grant += cli->cl_grant_extent_tax;
615                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
616                                 grant += cli->cl_grant_extent_tax;
617
618                         if (ext->oe_hp)
619                                 list_move_tail(&ext->oe_link,
620                                                &obj->oo_hp_exts);
621                         else if (ext->oe_urgent)
622                                 list_move_tail(&ext->oe_link,
623                                                &obj->oo_urgent_exts);
624                         else if (ext->oe_nr_pages == ext->oe_mppr) {
625                                 list_move_tail(&ext->oe_link,
626                                                &obj->oo_full_exts);
627                         }
628                         osc_object_unlock(obj);
629                         if (grant > 0)
630                                 osc_unreserve_grant(cli, 0, grant);
631                 }
632
633                 osc_io_unplug_async(env, cli, obj);
634         }
635         osc_extent_put(env, ext);
636
637         RETURN_EXIT;
638 }
639
640 /**
641  * Find or create an extent which includes @index, core function to manage
642  * extent tree.
643  */
644 static struct osc_extent *osc_extent_find(const struct lu_env *env,
645                                           struct osc_object *obj, pgoff_t index,
646                                           unsigned int *grants)
647 {
648         struct client_obd *cli = osc_cli(obj);
649         struct osc_lock   *olck;
650         struct cl_lock_descr *descr;
651         struct osc_extent *cur;
652         struct osc_extent *ext;
653         struct osc_extent *conflict = NULL;
654         struct osc_extent *found = NULL;
655         pgoff_t    chunk;
656         pgoff_t    max_end;
657         unsigned int max_pages; /* max_pages_per_rpc */
658         unsigned int chunksize;
659         int        ppc_bits; /* pages per chunk bits */
660         pgoff_t    chunk_mask;
661         int        rc;
662         ENTRY;
663
664         cur = osc_extent_alloc(obj);
665         if (cur == NULL)
666                 RETURN(ERR_PTR(-ENOMEM));
667
668         olck = osc_env_io(env)->oi_write_osclock;
669         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
670         LASSERT(olck->ols_state == OLS_GRANTED);
671
672         descr = &olck->ols_cl.cls_lock->cll_descr;
673         LASSERT(descr->cld_mode >= CLM_WRITE);
674
675         LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
676                  "chunkbits: %u\n", cli->cl_chunkbits);
677         ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
678         chunk_mask = ~((1 << ppc_bits) - 1);
679         chunksize  = 1 << cli->cl_chunkbits;
680         chunk      = index >> ppc_bits;
681
682         /* align end to RPC edge. */
683         max_pages = cli->cl_max_pages_per_rpc;
684         if ((max_pages & ~chunk_mask) != 0) {
685                 CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
686                        max_pages, cli->cl_chunkbits, chunk_mask);
687                 RETURN(ERR_PTR(-EINVAL));
688         }
689         max_end = index - (index % max_pages) + max_pages - 1;
690         max_end = min_t(pgoff_t, max_end, descr->cld_end);
691
692         /* initialize new extent by parameters so far */
693         cur->oe_max_end = max_end;
694         cur->oe_start   = index & chunk_mask;
695         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
696         if (cur->oe_start < descr->cld_start)
697                 cur->oe_start = descr->cld_start;
698         if (cur->oe_end > max_end)
699                 cur->oe_end = max_end;
700         cur->oe_grants  = chunksize + cli->cl_grant_extent_tax;
701         cur->oe_mppr    = max_pages;
702         if (olck->ols_dlmlock != NULL) {
703                 LASSERT(olck->ols_hold);
704                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
705                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
706         }
707
708         /* grants has been allocated by caller */
709         LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
710                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
711         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
712                  EXTPARA(cur));
713
714 restart:
715         osc_object_lock(obj);
716         ext = osc_extent_search(obj, cur->oe_start);
717         if (!ext)
718                 ext = first_extent(obj);
719         for (; ext; ext = next_extent(ext)) {
720                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
721                 pgoff_t ext_chk_end = ext->oe_end >> ppc_bits;
722
723                 LASSERT(sanity_check_nolock(ext) == 0);
724                 if (chunk > ext_chk_end + 1 || chunk < ext_chk_start)
725                         break;
726
727                 /* if covering by different locks, no chance to match */
728                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
729                         EASSERTF(!overlapped(ext, cur), ext,
730                                  EXTSTR"\n", EXTPARA(cur));
731
732                         continue;
733                 }
734
735                 /* discontiguous chunks? */
736                 if (chunk + 1 < ext_chk_start)
737                         continue;
738
739                 /* ok, from now on, ext and cur have these attrs:
740                  * 1. covered by the same lock
741                  * 2. contiguous at chunk level or overlapping. */
742
743                 if (overlapped(ext, cur)) {
744                         /* cur is the minimum unit, so overlapping means
745                          * full contain. */
746                         EASSERTF((ext->oe_start <= cur->oe_start &&
747                                   ext->oe_end >= cur->oe_end),
748                                  ext, EXTSTR"\n", EXTPARA(cur));
749
750                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
751                                 /* for simplicity, we wait for this extent to
752                                  * finish before going forward. */
753                                 conflict = osc_extent_get(ext);
754                                 break;
755                         }
756
757                         found = osc_extent_hold(ext);
758                         break;
759                 }
760
761                 /* non-overlapped extent */
762                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait)
763                         /* we can't do anything for a non OES_CACHE extent, or
764                          * if there is someone waiting for this extent to be
765                          * flushed, try next one. */
766                         continue;
767
768                 if (osc_extent_merge(env, ext, cur) == 0) {
769                         LASSERT(*grants >= chunksize);
770                         *grants -= chunksize;
771
772                         /*
773                          * Try to merge with the next one too because we
774                          * might have just filled in a gap.
775                          */
776                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
777                                 /* we can save extent tax from next extent */
778                                 *grants += cli->cl_grant_extent_tax;
779
780                         found = osc_extent_hold(ext);
781                         break;
782                 }
783         }
784
785         osc_extent_tree_dump(D_CACHE, obj);
786         if (found != NULL) {
787                 LASSERT(conflict == NULL);
788                 if (!IS_ERR(found)) {
789                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
790                         OSC_EXTENT_DUMP(D_CACHE, found,
791                                         "found caching ext for %lu.\n", index);
792                 }
793         } else if (conflict == NULL) {
794                 /* create a new extent */
795                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
796                 LASSERT(*grants >= cur->oe_grants);
797                 *grants -= cur->oe_grants;
798
799                 cur->oe_state = OES_CACHE;
800                 found = osc_extent_hold(cur);
801                 osc_extent_insert(obj, cur);
802                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
803                                 index, descr->cld_end);
804         }
805         osc_object_unlock(obj);
806
807         if (conflict != NULL) {
808                 LASSERT(found == NULL);
809
810                 /* waiting for IO to finish. Please notice that it's impossible
811                  * to be an OES_TRUNC extent. */
812                 rc = osc_extent_wait(env, conflict, OES_INV);
813                 osc_extent_put(env, conflict);
814                 conflict = NULL;
815                 if (rc < 0)
816                         GOTO(out, found = ERR_PTR(rc));
817
818                 goto restart;
819         }
820         EXIT;
821
822 out:
823         osc_extent_put(env, cur);
824         return found;
825 }
826
827 /**
828  * Called when IO is finished to an extent.
829  */
830 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
831                       int sent, int rc)
832 {
833         struct client_obd *cli = osc_cli(ext->oe_obj);
834         struct osc_async_page *oap;
835         struct osc_async_page *tmp;
836         int nr_pages = ext->oe_nr_pages;
837         int lost_grant = 0;
838         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
839         loff_t last_off = 0;
840         int last_count = -1;
841         ENTRY;
842
843         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
844
845         ext->oe_rc = rc ?: ext->oe_nr_pages;
846         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
847
848         osc_lru_add_batch(cli, &ext->oe_pages);
849         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
850                                      oap_pending_item) {
851                 list_del_init(&oap->oap_rpc_item);
852                 list_del_init(&oap->oap_pending_item);
853                 if (last_off <= oap->oap_obj_off) {
854                         last_off = oap->oap_obj_off;
855                         last_count = oap->oap_count;
856                 }
857
858                 --ext->oe_nr_pages;
859                 osc_ap_completion(env, cli, oap, sent, rc);
860         }
861         EASSERT(ext->oe_nr_pages == 0, ext);
862
863         if (!sent) {
864                 lost_grant = ext->oe_grants;
865         } else if (blocksize < PAGE_SIZE &&
866                    last_count != PAGE_SIZE) {
867                 /* For short writes we shouldn't count parts of pages that
868                  * span a whole chunk on the OST side, or our accounting goes
869                  * wrong.  Should match the code in filter_grant_check. */
870                 int offset = last_off & ~PAGE_MASK;
871                 int count = last_count + (offset & (blocksize - 1));
872                 int end = (offset + last_count) & (blocksize - 1);
873                 if (end)
874                         count += blocksize - end;
875
876                 lost_grant = PAGE_SIZE - count;
877         }
878         if (ext->oe_grants > 0)
879                 osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
880
881         osc_extent_remove(ext);
882         /* put the refcount for RPC */
883         osc_extent_put(env, ext);
884         RETURN(0);
885 }
886
887 /**
888  * Wait for the extent's state to become @state.
889  */
890 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
891                            enum osc_extent_state state)
892 {
893         struct osc_object *obj = ext->oe_obj;
894         int rc = 0;
895         ENTRY;
896
897         osc_object_lock(obj);
898         LASSERT(sanity_check_nolock(ext) == 0);
899         /* `Kick' this extent only if the caller is waiting for it to be
900          * written out. */
901         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
902                 if (ext->oe_state == OES_ACTIVE) {
903                         ext->oe_urgent = 1;
904                 } else if (ext->oe_state == OES_CACHE) {
905                         ext->oe_urgent = 1;
906                         osc_extent_hold(ext);
907                         rc = 1;
908                 }
909         }
910         osc_object_unlock(obj);
911         if (rc == 1)
912                 osc_extent_release(env, ext);
913
914         /* wait for the extent until its state becomes @state */
915         rc = wait_event_idle_timeout(ext->oe_waitq,
916                                      smp_load_acquire(&ext->oe_state) == state,
917                                      cfs_time_seconds(600));
918         if (rc == 0) {
919                 OSC_EXTENT_DUMP(D_ERROR, ext,
920                         "%s: wait ext to %u timedout, recovery in progress?\n",
921                         cli_name(osc_cli(obj)), state);
922
923                 wait_event_idle(ext->oe_waitq,
924                                 smp_load_acquire(&ext->oe_state) == state);
925         }
926         if (ext->oe_rc < 0)
927                 rc = ext->oe_rc;
928         else
929                 rc = 0;
930         RETURN(rc);
931 }
932
933 /**
934  * Discard pages with index greater than @size. If @ext is overlapped with
935  * @size, then partial truncate happens.
936  */
937 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
938                                 bool partial)
939 {
940         struct lu_env         *env;
941         struct cl_io          *io;
942         struct osc_object     *obj = ext->oe_obj;
943         struct client_obd     *cli = osc_cli(obj);
944         struct osc_async_page *oap;
945         struct osc_async_page *tmp;
946         struct pagevec        *pvec;
947         int                    pages_in_chunk = 0;
948         int                    ppc_bits    = cli->cl_chunkbits -
949                                              PAGE_SHIFT;
950         __u64                  trunc_chunk = trunc_index >> ppc_bits;
951         int                    grants   = 0;
952         int                    nr_pages = 0;
953         int                    rc       = 0;
954         __u16                  refcheck;
955         ENTRY;
956
957         LASSERT(sanity_check(ext) == 0);
958         LASSERT(ext->oe_state == OES_TRUNC);
959         LASSERT(!ext->oe_urgent);
960
961         /* Request new lu_env.
962          * We can't use that env from osc_cache_truncate_start() because
963          * it's from lov_io_sub and not fully initialized. */
964         env = cl_env_get(&refcheck);
965         if (IS_ERR(env))
966                 RETURN(PTR_ERR(env));
967
968         io  = osc_env_thread_io(env);
969         io->ci_obj = cl_object_top(osc2cl(obj));
970         io->ci_ignore_layout = 1;
971         pvec = &osc_env_info(env)->oti_pagevec;
972         ll_pagevec_init(pvec, 0);
973         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
974         if (rc < 0)
975                 GOTO(out, rc);
976
977         /* discard all pages with index greater than trunc_index */
978         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
979                                      oap_pending_item) {
980                 pgoff_t index = osc_index(oap2osc(oap));
981                 struct cl_page  *page = oap2cl_page(oap);
982
983                 LASSERT(list_empty(&oap->oap_rpc_item));
984
985                 /* only discard the pages with their index greater than
986                  * trunc_index, and ... */
987                 if (index < trunc_index ||
988                     (index == trunc_index && partial)) {
989                         /* accounting how many pages remaining in the chunk
990                          * so that we can calculate grants correctly. */
991                         if (index >> ppc_bits == trunc_chunk)
992                                 ++pages_in_chunk;
993                         continue;
994                 }
995
996                 list_del_init(&oap->oap_pending_item);
997
998                 cl_page_get(page);
999                 lu_ref_add(&page->cp_reference, "truncate", current);
1000
1001                 if (cl_page_own(env, io, page) == 0) {
1002                         cl_page_discard(env, io, page);
1003                         cl_page_disown(env, io, page);
1004                 } else {
1005                         LASSERT(page->cp_state == CPS_FREEING);
1006                         LASSERT(0);
1007                 }
1008
1009                 lu_ref_del(&page->cp_reference, "truncate", current);
1010                 cl_pagevec_put(env, page, pvec);
1011
1012                 --ext->oe_nr_pages;
1013                 ++nr_pages;
1014         }
1015         pagevec_release(pvec);
1016
1017         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1018                       ext->oe_nr_pages == 0),
1019                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1020
1021         osc_object_lock(obj);
1022         if (ext->oe_nr_pages == 0) {
1023                 LASSERT(pages_in_chunk == 0);
1024                 grants = ext->oe_grants;
1025                 ext->oe_grants = 0;
1026         } else { /* calculate how many grants we can free */
1027                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1028                 pgoff_t last_index;
1029
1030
1031                 /* if there is no pages in this chunk, we can also free grants
1032                  * for the last chunk */
1033                 if (pages_in_chunk == 0) {
1034                         /* if this is the 1st chunk and no pages in this chunk,
1035                          * ext->oe_nr_pages must be zero, so we should be in
1036                          * the other if-clause. */
1037                         LASSERT(trunc_chunk > 0);
1038                         --trunc_chunk;
1039                         ++chunks;
1040                 }
1041
1042                 /* this is what we can free from this extent */
1043                 grants          = chunks << cli->cl_chunkbits;
1044                 ext->oe_grants -= grants;
1045                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1046                 ext->oe_end     = min(last_index, ext->oe_max_end);
1047                 LASSERT(ext->oe_end >= ext->oe_start);
1048                 LASSERT(ext->oe_grants > 0);
1049         }
1050         osc_object_unlock(obj);
1051
1052         if (grants > 0 || nr_pages > 0)
1053                 osc_free_grant(cli, nr_pages, grants, grants);
1054
1055 out:
1056         cl_io_fini(env, io);
1057         cl_env_put(env, &refcheck);
1058         RETURN(rc);
1059 }
1060
1061 /**
1062  * This function is used to make the extent prepared for transfer.
1063  * A race with flusing page - ll_writepage() has to be handled cautiously.
1064  */
1065 static int osc_extent_make_ready(const struct lu_env *env,
1066                                  struct osc_extent *ext)
1067 {
1068         struct osc_async_page *oap;
1069         struct osc_async_page *last = NULL;
1070         struct osc_object *obj = ext->oe_obj;
1071         unsigned int page_count = 0;
1072         int rc;
1073         ENTRY;
1074
1075         /* we're going to grab page lock, so object lock must not be taken. */
1076         LASSERT(sanity_check(ext) == 0);
1077         /* in locking state, any process should not touch this extent. */
1078         EASSERT(ext->oe_state == OES_LOCKING, ext);
1079         EASSERT(ext->oe_owner != NULL, ext);
1080
1081         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1082
1083         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1084                 ++page_count;
1085                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1086                         last = oap;
1087
1088                 /* checking ASYNC_READY is race safe */
1089                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1090                         continue;
1091
1092                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1093                 switch (rc) {
1094                 case 0:
1095                         spin_lock(&oap->oap_lock);
1096                         oap->oap_async_flags |= ASYNC_READY;
1097                         spin_unlock(&oap->oap_lock);
1098                         break;
1099                 case -EALREADY:
1100                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1101                         break;
1102                 default:
1103                         LASSERTF(0, "unknown return code: %d\n", rc);
1104                 }
1105         }
1106
1107         LASSERT(page_count == ext->oe_nr_pages);
1108         LASSERT(last != NULL);
1109         /* the last page is the only one we need to refresh its count by
1110          * the size of file. */
1111         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1112                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1113                 LASSERTF(last_oap_count > 0,
1114                          "last_oap_count %d\n", last_oap_count);
1115                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
1116                 last->oap_count = last_oap_count;
1117                 spin_lock(&last->oap_lock);
1118                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1119                 spin_unlock(&last->oap_lock);
1120         }
1121
1122         /* for the rest of pages, we don't need to call osf_refresh_count()
1123          * because it's known they are not the last page */
1124         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1125                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1126                         oap->oap_count = PAGE_SIZE - oap->oap_page_off;
1127                         spin_lock(&oap->oap_lock);
1128                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1129                         spin_unlock(&oap->oap_lock);
1130                 }
1131         }
1132
1133         osc_object_lock(obj);
1134         osc_extent_state_set(ext, OES_RPC);
1135         osc_object_unlock(obj);
1136         /* get a refcount for RPC. */
1137         osc_extent_get(ext);
1138
1139         RETURN(0);
1140 }
1141
1142 /**
1143  * Quick and simple version of osc_extent_find(). This function is frequently
1144  * called to expand the extent for the same IO. To expand the extent, the
1145  * page index must be in the same or next chunk of ext->oe_end.
1146  */
1147 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1148                              unsigned int *grants)
1149 {
1150         struct osc_object *obj = ext->oe_obj;
1151         struct client_obd *cli = osc_cli(obj);
1152         struct osc_extent *next;
1153         int ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1154         pgoff_t chunk = index >> ppc_bits;
1155         pgoff_t end_chunk;
1156         pgoff_t end_index;
1157         unsigned int chunksize = 1 << cli->cl_chunkbits;
1158         int rc = 0;
1159         ENTRY;
1160
1161         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1162         osc_object_lock(obj);
1163         LASSERT(sanity_check_nolock(ext) == 0);
1164         end_chunk = ext->oe_end >> ppc_bits;
1165         if (chunk > end_chunk + 1)
1166                 GOTO(out, rc = -ERANGE);
1167
1168         if (end_chunk >= chunk)
1169                 GOTO(out, rc = 0);
1170
1171         LASSERT(end_chunk + 1 == chunk);
1172
1173         /* try to expand this extent to cover @index */
1174         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1175
1176         /* don't go over the maximum extent size reported by server */
1177         if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
1178                 GOTO(out, rc = -ERANGE);
1179
1180         next = next_extent(ext);
1181         if (next != NULL && next->oe_start <= end_index)
1182                 /* complex mode - overlapped with the next extent,
1183                  * this case will be handled by osc_extent_find() */
1184                 GOTO(out, rc = -EAGAIN);
1185
1186         ext->oe_end = end_index;
1187         ext->oe_grants += chunksize;
1188         LASSERT(*grants >= chunksize);
1189         *grants -= chunksize;
1190         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1191                  "overlapped after expanding for %lu.\n", index);
1192         EXIT;
1193
1194 out:
1195         osc_object_unlock(obj);
1196         RETURN(rc);
1197 }
1198
1199 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
1200                                   const char *func, int line)
1201 {
1202         struct osc_extent *ext;
1203         int cnt;
1204
1205         if (!cfs_cdebug_show(mask, DEBUG_SUBSYSTEM))
1206                 return;
1207
1208         CDEBUG(mask, "Dump object %p extents at %s:%d, mppr: %u.\n",
1209                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1210
1211         /* osc_object_lock(obj); */
1212         cnt = 1;
1213         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1214                 OSC_EXTENT_DUMP(mask, ext, "in tree %d.\n", cnt++);
1215
1216         cnt = 1;
1217         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1218                 OSC_EXTENT_DUMP(mask, ext, "hp %d.\n", cnt++);
1219
1220         cnt = 1;
1221         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1222                 OSC_EXTENT_DUMP(mask, ext, "urgent %d.\n", cnt++);
1223
1224         cnt = 1;
1225         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1226                 OSC_EXTENT_DUMP(mask, ext, "reading %d.\n", cnt++);
1227         /* osc_object_unlock(obj); */
1228 }
1229
1230 /* ------------------ osc extent end ------------------ */
1231
1232 static inline int osc_is_ready(struct osc_object *osc)
1233 {
1234         return !list_empty(&osc->oo_ready_item) ||
1235                !list_empty(&osc->oo_hp_ready_item);
1236 }
1237
1238 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1239         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1240                (OSC), osc_is_ready(OSC),                                       \
1241                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1242                list_empty_marker(&(OSC)->oo_ready_item),                       \
1243                atomic_read(&(OSC)->oo_nr_writes),                              \
1244                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1245                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1246                atomic_read(&(OSC)->oo_nr_reads),                               \
1247                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1248                ##args)
1249
1250 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1251                           int cmd)
1252 {
1253         struct osc_page *opg  = oap2osc_page(oap);
1254         struct cl_page  *page = oap2cl_page(oap);
1255         int result;
1256
1257         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1258
1259         ENTRY;
1260         result = cl_page_make_ready(env, page, CRT_WRITE);
1261         if (result == 0)
1262                 opg->ops_submit_time = ktime_get();
1263         RETURN(result);
1264 }
1265
1266 static int osc_refresh_count(const struct lu_env *env,
1267                              struct osc_async_page *oap, int cmd)
1268 {
1269         struct osc_page  *opg = oap2osc_page(oap);
1270         pgoff_t index = osc_index(oap2osc(oap));
1271         struct cl_object *obj;
1272         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1273         int result;
1274         loff_t kms;
1275
1276         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1277         LASSERT(!(cmd & OBD_BRW_READ));
1278         LASSERT(opg != NULL);
1279         obj = opg->ops_cl.cpl_obj;
1280
1281         cl_object_attr_lock(obj);
1282         result = cl_object_attr_get(env, obj, attr);
1283         cl_object_attr_unlock(obj);
1284         if (result < 0)
1285                 return result;
1286         kms = attr->cat_kms;
1287         if (cl_offset(obj, index) >= kms)
1288                 /* catch race with truncate */
1289                 return 0;
1290         else if (cl_offset(obj, index + 1) > kms)
1291                 /* catch sub-page write at end of file */
1292                 return kms & ~PAGE_MASK;
1293         else
1294                 return PAGE_SIZE;
1295 }
1296
1297 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1298                           int cmd, int rc)
1299 {
1300         struct osc_page   *opg  = oap2osc_page(oap);
1301         struct cl_page    *page = oap2cl_page(oap);
1302         enum cl_req_type   crt;
1303         int srvlock;
1304
1305         ENTRY;
1306
1307         cmd &= ~OBD_BRW_NOQUOTA;
1308         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1309                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1310         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1311                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1312         LASSERT(opg->ops_transfer_pinned);
1313
1314         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1315         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1316         opg->ops_transfer_pinned = 0;
1317
1318         opg->ops_submit_time = ktime_set(0, 0);
1319         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1320
1321         /* statistic */
1322         if (rc == 0 && srvlock) {
1323                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1324                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1325                 size_t bytes = oap->oap_count;
1326
1327                 if (crt == CRT_READ)
1328                         stats->os_lockless_reads += bytes;
1329                 else
1330                         stats->os_lockless_writes += bytes;
1331         }
1332
1333         /*
1334          * This has to be the last operation with the page, as locks are
1335          * released in cl_page_completion() and nothing except for the
1336          * reference counter protects page from concurrent reclaim.
1337          */
1338         lu_ref_del(&page->cp_reference, "transfer", page);
1339
1340         cl_page_completion(env, page, crt, rc);
1341         cl_page_put(env, page);
1342
1343         RETURN(0);
1344 }
1345
1346 #define OSC_DUMP_GRANT(mask, cli, fmt, args...) do {                    \
1347         struct client_obd *__tmp = (cli);                               \
1348         CDEBUG(mask, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu " \
1349                "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
1350                "reserved: %ld, flight: %d } lru {in list: %ld, "        \
1351                "left: %ld, waiters: %d }" fmt "\n",                     \
1352                cli_name(__tmp),                                         \
1353                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1354                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1355                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1356                __tmp->cl_dirty_grant,                                   \
1357                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1358                atomic_long_read(&__tmp->cl_lru_in_list),                \
1359                atomic_long_read(&__tmp->cl_lru_busy),                   \
1360                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1361 } while (0)
1362
1363 /* caller must hold loi_list_lock */
1364 static void osc_consume_write_grant(struct client_obd *cli,
1365                                     struct brw_page *pga)
1366 {
1367         assert_spin_locked(&cli->cl_loi_list_lock);
1368         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1369         cli->cl_dirty_pages++;
1370         pga->flag |= OBD_BRW_FROM_GRANT;
1371         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1372                PAGE_SIZE, pga, pga->pg);
1373 }
1374
1375 /* the companion to osc_consume_write_grant, called when a brw has completed.
1376  * must be called with the loi lock held. */
1377 static void osc_release_write_grant(struct client_obd *cli,
1378                                     struct brw_page *pga)
1379 {
1380         ENTRY;
1381
1382         assert_spin_locked(&cli->cl_loi_list_lock);
1383         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1384                 EXIT;
1385                 return;
1386         }
1387
1388         pga->flag &= ~OBD_BRW_FROM_GRANT;
1389         atomic_long_dec(&obd_dirty_pages);
1390         cli->cl_dirty_pages--;
1391         EXIT;
1392 }
1393
1394 /**
1395  * To avoid sleeping with object lock held, it's good for us allocate enough
1396  * grants before entering into critical section.
1397  *
1398  * client_obd_list_lock held by caller
1399  */
1400 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1401 {
1402         int rc = -EDQUOT;
1403
1404         if (cli->cl_avail_grant >= bytes) {
1405                 cli->cl_avail_grant    -= bytes;
1406                 cli->cl_reserved_grant += bytes;
1407                 rc = 0;
1408         }
1409         return rc;
1410 }
1411
1412 static void __osc_unreserve_grant(struct client_obd *cli,
1413                                   unsigned int reserved, unsigned int unused)
1414 {
1415         /* it's quite normal for us to get more grant than reserved.
1416          * Thinking about a case that two extents merged by adding a new
1417          * chunk, we can save one extent tax. If extent tax is greater than
1418          * one chunk, we can save more grant by adding a new chunk */
1419         cli->cl_reserved_grant -= reserved;
1420         if (unused > reserved) {
1421                 cli->cl_avail_grant += reserved;
1422                 cli->cl_lost_grant  += unused - reserved;
1423                 cli->cl_dirty_grant -= unused - reserved;
1424         } else {
1425                 cli->cl_avail_grant += unused;
1426                 cli->cl_dirty_grant += reserved - unused;
1427         }
1428 }
1429
1430 static void osc_unreserve_grant_nolock(struct client_obd *cli,
1431                                        unsigned int reserved,
1432                                        unsigned int unused)
1433 {
1434         __osc_unreserve_grant(cli, reserved, unused);
1435         if (unused > 0)
1436                 osc_wake_cache_waiters(cli);
1437 }
1438
1439 static void osc_unreserve_grant(struct client_obd *cli,
1440                                 unsigned int reserved, unsigned int unused)
1441 {
1442         spin_lock(&cli->cl_loi_list_lock);
1443         osc_unreserve_grant_nolock(cli, reserved, unused);
1444         spin_unlock(&cli->cl_loi_list_lock);
1445 }
1446
1447 /**
1448  * Free grant after IO is finished or canceled.
1449  *
1450  * @lost_grant is used to remember how many grants we have allocated but not
1451  * used, we should return these grants to OST. There're two cases where grants
1452  * can be lost:
1453  * 1. truncate;
1454  * 2. blocksize at OST is less than PAGE_SIZE and a partial page was
1455  *    written. In this case OST may use less chunks to serve this partial
1456  *    write. OSTs don't actually know the page size on the client side. so
1457  *    clients have to calculate lost grant by the blocksize on the OST.
1458  *    See filter_grant_check() for details.
1459  */
1460 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1461                            unsigned int lost_grant, unsigned int dirty_grant)
1462 {
1463         unsigned long grant;
1464
1465         grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
1466
1467         spin_lock(&cli->cl_loi_list_lock);
1468         atomic_long_sub(nr_pages, &obd_dirty_pages);
1469         cli->cl_dirty_pages -= nr_pages;
1470         cli->cl_lost_grant += lost_grant;
1471         cli->cl_dirty_grant -= dirty_grant;
1472         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1473                 /* borrow some grant from truncate to avoid the case that
1474                  * truncate uses up all avail grant */
1475                 cli->cl_lost_grant -= grant;
1476                 cli->cl_avail_grant += grant;
1477         }
1478         osc_wake_cache_waiters(cli);
1479         spin_unlock(&cli->cl_loi_list_lock);
1480         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
1481                lost_grant, cli->cl_lost_grant,
1482                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_SHIFT,
1483                cli->cl_dirty_grant);
1484 }
1485
1486 /**
1487  * The companion to osc_enter_cache(), called when @oap is no longer part of
1488  * the dirty accounting due to error.
1489  */
1490 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1491 {
1492         spin_lock(&cli->cl_loi_list_lock);
1493         osc_release_write_grant(cli, &oap->oap_brw_page);
1494         spin_unlock(&cli->cl_loi_list_lock);
1495 }
1496
1497 /**
1498  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1499  * is available.
1500  */
1501 static int osc_enter_cache_try(struct client_obd *cli,
1502                                struct osc_async_page *oap,
1503                                int bytes)
1504 {
1505         int rc;
1506
1507         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1508
1509         rc = osc_reserve_grant(cli, bytes);
1510         if (rc < 0)
1511                 return 0;
1512
1513         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages) {
1514                 if (atomic_long_add_return(1, &obd_dirty_pages) <=
1515                     obd_max_dirty_pages) {
1516                         osc_consume_write_grant(cli, &oap->oap_brw_page);
1517                         rc = 1;
1518                         goto out;
1519                 } else
1520                         atomic_long_dec(&obd_dirty_pages);
1521         }
1522         __osc_unreserve_grant(cli, bytes, bytes);
1523
1524 out:
1525         return rc;
1526 }
1527
1528 /* Following two inlines exist to pass code fragments
1529  * to wait_event_idle_exclusive_timeout_cmd().  Passing
1530  * code fragments as macro args can look confusing, so
1531  * we provide inlines to encapsulate them.
1532  */
1533 static inline void cli_unlock_and_unplug(const struct lu_env *env,
1534                                          struct client_obd *cli,
1535                                          struct osc_async_page *oap)
1536 {
1537         spin_unlock(&cli->cl_loi_list_lock);
1538         osc_io_unplug_async(env, cli, NULL);
1539         CDEBUG(D_CACHE,
1540                "%s: sleeping for cache space for %p\n",
1541                cli_name(cli), oap);
1542 }
1543
1544 static inline void cli_lock_after_unplug(struct client_obd *cli)
1545 {
1546         spin_lock(&cli->cl_loi_list_lock);
1547 }
1548 /**
1549  * The main entry to reserve dirty page accounting. Usually the grant reserved
1550  * in this function will be freed in bulk in osc_free_grant() unless it fails
1551  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1552  *
1553  * The process will be put into sleep if it's already run out of grant.
1554  */
1555 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1556                            struct osc_async_page *oap, int bytes)
1557 {
1558         struct osc_object *osc = oap->oap_obj;
1559         struct lov_oinfo *loi = osc->oo_oinfo;
1560         int rc = -EDQUOT;
1561         int remain;
1562         bool entered = false;
1563         /* We cannot wait for a long time here since we are holding ldlm lock
1564          * across the actual IO. If no requests complete fast (e.g. due to
1565          * overloaded OST that takes a long time to process everything, we'd
1566          * get evicted if we wait for a normal obd_timeout or some such.
1567          * So we try to wait half the time it would take the client to be
1568          * evicted by server which is half obd_timeout when AT is off
1569          * or at least ldlm_enqueue_min with AT on.
1570          * See LU-13131 */
1571         unsigned long timeout = cfs_time_seconds(AT_OFF ? obd_timeout / 2 :
1572                                                           ldlm_enqueue_min / 2);
1573
1574         ENTRY;
1575
1576         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1577
1578         spin_lock(&cli->cl_loi_list_lock);
1579
1580         /* force the caller to try sync io.  this can jump the list
1581          * of queued writes and create a discontiguous rpc stream */
1582         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1583             cli->cl_dirty_max_pages == 0 ||
1584             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1585                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1586                 GOTO(out, rc = -EDQUOT);
1587         }
1588
1589         /*
1590          * We can wait here for two reasons: too many dirty pages in cache, or
1591          * run out of grants. In both cases we should write dirty pages out.
1592          * Adding a cache waiter will trigger urgent write-out no matter what
1593          * RPC size will be.
1594          * The exiting condition (other than success) is no avail grants
1595          * and no dirty pages caching, that really means there is no space
1596          * on the OST.
1597          */
1598         remain = wait_event_idle_exclusive_timeout_cmd(
1599                 cli->cl_cache_waiters,
1600                 (entered = osc_enter_cache_try(cli, oap, bytes)) ||
1601                 (cli->cl_dirty_pages == 0 && cli->cl_w_in_flight == 0),
1602                 timeout,
1603                 cli_unlock_and_unplug(env, cli, oap),
1604                 cli_lock_after_unplug(cli));
1605
1606         if (entered) {
1607                 if (remain == timeout)
1608                         OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1609                 else
1610                         OSC_DUMP_GRANT(D_CACHE, cli,
1611                                        "finally got grant space\n");
1612                 wake_up(&cli->cl_cache_waiters);
1613                 rc = 0;
1614         } else if (remain == 0) {
1615                 OSC_DUMP_GRANT(D_CACHE, cli,
1616                                "timeout, fall back to sync i/o\n");
1617                 osc_extent_tree_dump(D_CACHE, osc);
1618                 /* fall back to synchronous I/O */
1619         } else {
1620                 OSC_DUMP_GRANT(D_CACHE, cli,
1621                                "no grant space, fall back to sync i/o\n");
1622                 wake_up_all(&cli->cl_cache_waiters);
1623         }
1624         EXIT;
1625 out:
1626         spin_unlock(&cli->cl_loi_list_lock);
1627         RETURN(rc);
1628 }
1629
1630 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1631 {
1632         int hprpc = !!list_empty(&osc->oo_hp_exts);
1633         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1634 }
1635
1636 /* This maintains the lists of pending pages to read/write for a given object
1637  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1638  * to quickly find objects that are ready to send an RPC. */
1639 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1640                          int cmd)
1641 {
1642         int invalid_import = 0;
1643         ENTRY;
1644
1645         /* if we have an invalid import we want to drain the queued pages
1646          * by forcing them through rpcs that immediately fail and complete
1647          * the pages.  recovery relies on this to empty the queued pages
1648          * before canceling the locks and evicting down the llite pages */
1649         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1650                 invalid_import = 1;
1651
1652         if (cmd & OBD_BRW_WRITE) {
1653                 if (atomic_read(&osc->oo_nr_writes) == 0)
1654                         RETURN(0);
1655                 if (invalid_import) {
1656                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1657                         RETURN(1);
1658                 }
1659                 if (!list_empty(&osc->oo_hp_exts)) {
1660                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1661                         RETURN(1);
1662                 }
1663                 if (!list_empty(&osc->oo_urgent_exts)) {
1664                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1665                         RETURN(1);
1666                 }
1667                 /* trigger a write rpc stream as long as there are dirtiers
1668                  * waiting for space.  as they're waiting, they're not going to
1669                  * create more pages to coalesce with what's waiting..
1670                  */
1671                 if (waitqueue_active(&cli->cl_cache_waiters)) {
1672                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1673                         RETURN(1);
1674                 }
1675                 if (!list_empty(&osc->oo_full_exts)) {
1676                         CDEBUG(D_CACHE, "full extent ready, make an RPC\n");
1677                         RETURN(1);
1678                 }
1679         } else {
1680                 if (atomic_read(&osc->oo_nr_reads) == 0)
1681                         RETURN(0);
1682                 if (invalid_import) {
1683                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1684                         RETURN(1);
1685                 }
1686                 /* all read are urgent. */
1687                 if (!list_empty(&osc->oo_reading_exts))
1688                         RETURN(1);
1689         }
1690
1691         RETURN(0);
1692 }
1693
1694 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1695 {
1696         struct client_obd *cli = osc_cli(obj);
1697         if (cmd & OBD_BRW_WRITE) {
1698                 atomic_add(delta, &obj->oo_nr_writes);
1699                 atomic_add(delta, &cli->cl_pending_w_pages);
1700                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1701         } else {
1702                 atomic_add(delta, &obj->oo_nr_reads);
1703                 atomic_add(delta, &cli->cl_pending_r_pages);
1704                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1705         }
1706         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1707 }
1708
1709 static int osc_makes_hprpc(struct osc_object *obj)
1710 {
1711         return !list_empty(&obj->oo_hp_exts);
1712 }
1713
1714 static void on_list(struct list_head *item, struct list_head *list,
1715                     int should_be_on)
1716 {
1717         if (list_empty(item) && should_be_on)
1718                 list_add_tail(item, list);
1719         else if (!list_empty(item) && !should_be_on)
1720                 list_del_init(item);
1721 }
1722
1723 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1724  * can find pages to build into rpcs quickly */
1725 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1726 {
1727         if (osc_makes_hprpc(osc)) {
1728                 /* HP rpc */
1729                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1730                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1731         } else {
1732                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1733                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1734                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1735                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1736         }
1737
1738         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1739                 atomic_read(&osc->oo_nr_writes) > 0);
1740
1741         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1742                 atomic_read(&osc->oo_nr_reads) > 0);
1743
1744         return osc_is_ready(osc);
1745 }
1746
1747 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1748 {
1749         int is_ready;
1750
1751         spin_lock(&cli->cl_loi_list_lock);
1752         is_ready = __osc_list_maint(cli, osc);
1753         spin_unlock(&cli->cl_loi_list_lock);
1754
1755         return is_ready;
1756 }
1757
1758 /* this is trying to propogate async writeback errors back up to the
1759  * application.  As an async write fails we record the error code for later if
1760  * the app does an fsync.  As long as errors persist we force future rpcs to be
1761  * sync so that the app can get a sync error and break the cycle of queueing
1762  * pages for which writeback will fail. */
1763 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1764                            int rc)
1765 {
1766         if (rc) {
1767                 if (!ar->ar_rc)
1768                         ar->ar_rc = rc;
1769
1770                 ar->ar_force_sync = 1;
1771                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1772                 return;
1773
1774         }
1775
1776         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1777                 ar->ar_force_sync = 0;
1778 }
1779
1780 /* this must be called holding the loi list lock to give coverage to exit_cache,
1781  * async_flag maintenance, and oap_request */
1782 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1783                               struct osc_async_page *oap, int sent, int rc)
1784 {
1785         struct osc_object *osc = oap->oap_obj;
1786         struct lov_oinfo  *loi = osc->oo_oinfo;
1787         __u64 xid = 0;
1788
1789         ENTRY;
1790         if (oap->oap_request != NULL) {
1791                 xid = ptlrpc_req_xid(oap->oap_request);
1792                 ptlrpc_req_finished(oap->oap_request);
1793                 oap->oap_request = NULL;
1794         }
1795
1796         /* As the transfer for this page is being done, clear the flags */
1797         spin_lock(&oap->oap_lock);
1798         oap->oap_async_flags = 0;
1799         spin_unlock(&oap->oap_lock);
1800
1801         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1802                 spin_lock(&cli->cl_loi_list_lock);
1803                 osc_process_ar(&cli->cl_ar, xid, rc);
1804                 osc_process_ar(&loi->loi_ar, xid, rc);
1805                 spin_unlock(&cli->cl_loi_list_lock);
1806         }
1807
1808         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1809         if (rc)
1810                 CERROR("completion on oap %p obj %p returns %d.\n",
1811                        oap, osc, rc);
1812
1813         EXIT;
1814 }
1815
1816 struct extent_rpc_data {
1817         struct list_head        *erd_rpc_list;
1818         unsigned int            erd_page_count;
1819         unsigned int            erd_max_pages;
1820         unsigned int            erd_max_chunks;
1821         unsigned int            erd_max_extents;
1822 };
1823
1824 static inline unsigned osc_extent_chunks(const struct osc_extent *ext)
1825 {
1826         struct client_obd *cli = osc_cli(ext->oe_obj);
1827         unsigned ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1828
1829         return (ext->oe_end >> ppc_bits) - (ext->oe_start >> ppc_bits) + 1;
1830 }
1831
1832 static inline bool
1833 can_merge(const struct osc_extent *ext, const struct osc_extent *in_rpc)
1834 {
1835         if (ext->oe_no_merge || in_rpc->oe_no_merge)
1836                 return false;
1837
1838         if (ext->oe_srvlock != in_rpc->oe_srvlock)
1839                 return false;
1840
1841         if (ext->oe_ndelay != in_rpc->oe_ndelay)
1842                 return false;
1843
1844         if (!ext->oe_grants != !in_rpc->oe_grants)
1845                 return false;
1846
1847         if (ext->oe_dio != in_rpc->oe_dio)
1848                 return false;
1849
1850         /* It's possible to have overlap on DIO */
1851         if (in_rpc->oe_dio && overlapped(ext, in_rpc))
1852                 return false;
1853
1854         if (ext->oe_is_rdma_only != in_rpc->oe_is_rdma_only)
1855                 return false;
1856
1857         return true;
1858 }
1859
1860 /**
1861  * Try to add extent to one RPC. We need to think about the following things:
1862  * - # of pages must not be over max_pages_per_rpc
1863  * - extent must be compatible with previous ones
1864  */
1865 static int try_to_add_extent_for_io(struct client_obd *cli,
1866                                     struct osc_extent *ext,
1867                                     struct extent_rpc_data *data)
1868 {
1869         struct osc_extent *tmp;
1870         unsigned int chunk_count;
1871         ENTRY;
1872
1873         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1874                 ext);
1875         OSC_EXTENT_DUMP(D_CACHE, ext, "trying to add this extent\n");
1876
1877         if (data->erd_max_extents == 0)
1878                 RETURN(0);
1879
1880         chunk_count = osc_extent_chunks(ext);
1881         EASSERTF(data->erd_page_count != 0 ||
1882                  chunk_count <= data->erd_max_chunks, ext,
1883                  "The first extent to be fit in a RPC contains %u chunks, "
1884                  "which is over the limit %u.\n", chunk_count,
1885                  data->erd_max_chunks);
1886         if (chunk_count > data->erd_max_chunks)
1887                 RETURN(0);
1888
1889         data->erd_max_pages = max(ext->oe_mppr, data->erd_max_pages);
1890         EASSERTF(data->erd_page_count != 0 ||
1891                 ext->oe_nr_pages <= data->erd_max_pages, ext,
1892                 "The first extent to be fit in a RPC contains %u pages, "
1893                 "which is over the limit %u.\n", ext->oe_nr_pages,
1894                 data->erd_max_pages);
1895         if (data->erd_page_count + ext->oe_nr_pages > data->erd_max_pages)
1896                 RETURN(0);
1897
1898         list_for_each_entry(tmp, data->erd_rpc_list, oe_link) {
1899                 EASSERT(tmp->oe_owner == current, tmp);
1900
1901                 if (!can_merge(ext, tmp))
1902                         RETURN(0);
1903         }
1904
1905         data->erd_max_extents--;
1906         data->erd_max_chunks -= chunk_count;
1907         data->erd_page_count += ext->oe_nr_pages;
1908         list_move_tail(&ext->oe_link, data->erd_rpc_list);
1909         ext->oe_owner = current;
1910         RETURN(1);
1911 }
1912
1913 /**
1914  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1915  * get_write_extent() takes all appropriate extents in atomic.
1916  *
1917  * The following policy is used to collect extents for IO:
1918  * 1. Add as many HP extents as possible;
1919  * 2. Add the first urgent extent in urgent extent list and take it out of
1920  *    urgent list;
1921  * 3. Add subsequent extents of this urgent extent;
1922  * 4. If urgent list is not empty, goto 2;
1923  * 5. Traverse the extent tree from the 1st extent;
1924  * 6. Above steps exit if there is no space in this RPC.
1925  */
1926 static unsigned int get_write_extents(struct osc_object *obj,
1927                                       struct list_head *rpclist)
1928 {
1929         struct client_obd *cli = osc_cli(obj);
1930         struct osc_extent *ext;
1931         struct extent_rpc_data data = {
1932                 .erd_rpc_list   = rpclist,
1933                 .erd_page_count = 0,
1934                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
1935                 .erd_max_chunks = osc_max_write_chunks(cli),
1936                 .erd_max_extents = 256,
1937         };
1938
1939         assert_osc_object_is_locked(obj);
1940         while ((ext = list_first_entry_or_null(&obj->oo_hp_exts,
1941                                                struct osc_extent,
1942                                                oe_link)) != NULL) {
1943                 if (!try_to_add_extent_for_io(cli, ext, &data))
1944                         return data.erd_page_count;
1945                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
1946         }
1947         if (data.erd_page_count == data.erd_max_pages)
1948                 return data.erd_page_count;
1949
1950         while ((ext = list_first_entry_or_null(&obj->oo_urgent_exts,
1951                                                struct osc_extent,
1952                                                oe_link)) != NULL) {
1953                 if (!try_to_add_extent_for_io(cli, ext, &data))
1954                         return data.erd_page_count;
1955         }
1956         if (data.erd_page_count == data.erd_max_pages)
1957                 return data.erd_page_count;
1958
1959         /* One key difference between full extents and other extents: full
1960          * extents can usually only be added if the rpclist was empty, so if we
1961          * can't add one, we continue on to trying to add normal extents.  This
1962          * is so we don't miss adding extra extents to an RPC containing high
1963          * priority or urgent extents.
1964          */
1965         while ((ext = list_first_entry_or_null(&obj->oo_full_exts,
1966                                                struct osc_extent,
1967                                                oe_link)) != NULL) {
1968                 if (!try_to_add_extent_for_io(cli, ext, &data))
1969                         break;
1970         }
1971         if (data.erd_page_count == data.erd_max_pages)
1972                 return data.erd_page_count;
1973
1974         for (ext = first_extent(obj);
1975              ext;
1976              ext = next_extent(ext)) {
1977                 if ((ext->oe_state != OES_CACHE) ||
1978                     /* this extent may be already in current rpclist */
1979                     (!list_empty(&ext->oe_link) && ext->oe_owner))
1980                         continue;
1981
1982                 if (!try_to_add_extent_for_io(cli, ext, &data))
1983                         return data.erd_page_count;
1984         }
1985         return data.erd_page_count;
1986 }
1987
1988 static int
1989 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1990                    struct osc_object *osc)
1991 __must_hold(osc)
1992 {
1993         LIST_HEAD(rpclist);
1994         struct osc_extent *ext;
1995         struct osc_extent *tmp;
1996         struct osc_extent *first = NULL;
1997         unsigned int page_count = 0;
1998         int srvlock = 0;
1999         int rc = 0;
2000         ENTRY;
2001
2002         assert_osc_object_is_locked(osc);
2003
2004         page_count = get_write_extents(osc, &rpclist);
2005         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
2006
2007         if (list_empty(&rpclist))
2008                 RETURN(0);
2009
2010         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
2011
2012         list_for_each_entry(ext, &rpclist, oe_link) {
2013                 LASSERT(ext->oe_state == OES_CACHE ||
2014                         ext->oe_state == OES_LOCK_DONE);
2015                 if (ext->oe_state == OES_CACHE)
2016                         osc_extent_state_set(ext, OES_LOCKING);
2017                 else
2018                         osc_extent_state_set(ext, OES_RPC);
2019         }
2020
2021         /* we're going to grab page lock, so release object lock because
2022          * lock order is page lock -> object lock. */
2023         osc_object_unlock(osc);
2024
2025         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2026                 if (ext->oe_state == OES_LOCKING) {
2027                         rc = osc_extent_make_ready(env, ext);
2028                         if (unlikely(rc < 0)) {
2029                                 list_del_init(&ext->oe_link);
2030                                 osc_extent_finish(env, ext, 0, rc);
2031                                 continue;
2032                         }
2033                 }
2034                 if (first == NULL) {
2035                         first = ext;
2036                         srvlock = ext->oe_srvlock;
2037                 } else {
2038                         LASSERT(srvlock == ext->oe_srvlock);
2039                 }
2040         }
2041
2042         if (!list_empty(&rpclist)) {
2043                 LASSERT(page_count > 0);
2044                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2045                 LASSERT(list_empty(&rpclist));
2046         }
2047
2048         osc_object_lock(osc);
2049         RETURN(rc);
2050 }
2051
2052 /**
2053  * prepare pages for ASYNC io and put pages in send queue.
2054  *
2055  * \param cmd OBD_BRW_* macroses
2056  * \param lop pending pages
2057  *
2058  * \return zero if no page added to send queue.
2059  * \return 1 if pages successfully added to send queue.
2060  * \return negative on errors.
2061  */
2062 static int
2063 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2064                   struct osc_object *osc)
2065 __must_hold(osc)
2066 {
2067         struct osc_extent *ext;
2068         struct osc_extent *next;
2069         LIST_HEAD(rpclist);
2070         struct extent_rpc_data data = {
2071                 .erd_rpc_list   = &rpclist,
2072                 .erd_page_count = 0,
2073                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2074                 .erd_max_chunks = UINT_MAX,
2075                 .erd_max_extents = UINT_MAX,
2076         };
2077         int rc = 0;
2078         ENTRY;
2079
2080         assert_osc_object_is_locked(osc);
2081         list_for_each_entry_safe(ext, next, &osc->oo_reading_exts, oe_link) {
2082                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2083                 if (!try_to_add_extent_for_io(cli, ext, &data))
2084                         break;
2085                 osc_extent_state_set(ext, OES_RPC);
2086                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2087         }
2088         LASSERT(data.erd_page_count <= data.erd_max_pages);
2089
2090         osc_update_pending(osc, OBD_BRW_READ, -data.erd_page_count);
2091
2092         if (!list_empty(&rpclist)) {
2093                 osc_object_unlock(osc);
2094
2095                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2096                 LASSERT(list_empty(&rpclist));
2097
2098                 osc_object_lock(osc);
2099         }
2100         RETURN(rc);
2101 }
2102
2103 #define list_to_obj(list, item) ({                                            \
2104         struct list_head *__tmp = (list)->next;                               \
2105         list_del_init(__tmp);                                         \
2106         list_entry(__tmp, struct osc_object, oo_##item);                      \
2107 })
2108
2109 /* This is called by osc_check_rpcs() to find which objects have pages that
2110  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2111 static struct osc_object *osc_next_obj(struct client_obd *cli)
2112 {
2113         ENTRY;
2114
2115         /* First return objects that have blocked locks so that they
2116          * will be flushed quickly and other clients can get the lock,
2117          * then objects which have pages ready to be stuffed into RPCs */
2118         if (!list_empty(&cli->cl_loi_hp_ready_list))
2119                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2120         if (!list_empty(&cli->cl_loi_ready_list))
2121                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2122
2123         /* then if we have cache waiters, return all objects with queued
2124          * writes.  This is especially important when many small files
2125          * have filled up the cache and not been fired into rpcs because
2126          * they don't pass the nr_pending/object threshhold
2127          */
2128         if (waitqueue_active(&cli->cl_cache_waiters) &&
2129             !list_empty(&cli->cl_loi_write_list))
2130                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2131
2132         /* then return all queued objects when we have an invalid import
2133          * so that they get flushed */
2134         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2135                 if (!list_empty(&cli->cl_loi_write_list))
2136                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2137                                            write_item));
2138                 if (!list_empty(&cli->cl_loi_read_list))
2139                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2140                                            read_item));
2141         }
2142         RETURN(NULL);
2143 }
2144
2145 /* called with the loi list lock held */
2146 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2147 __must_hold(&cli->cl_loi_list_lock)
2148 {
2149         struct osc_object *osc;
2150         int rc = 0;
2151         ENTRY;
2152
2153         while ((osc = osc_next_obj(cli)) != NULL) {
2154                 struct cl_object *obj = osc2cl(osc);
2155                 struct lu_ref_link link;
2156
2157                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2158
2159                 /* even if we have reached our max in flight RPCs, we still
2160                  * allow all high-priority RPCs through to prevent their
2161                  * starvation and leading to server evicting us for not
2162                  * writing out pages in a timely manner LU-13131 */
2163                 if (osc_max_rpc_in_flight(cli, osc) &&
2164                     list_empty(&osc->oo_hp_exts)) {
2165                         __osc_list_maint(cli, osc);
2166                         break;
2167                 }
2168
2169                 cl_object_get(obj);
2170                 spin_unlock(&cli->cl_loi_list_lock);
2171                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2172
2173                 /* attempt some read/write balancing by alternating between
2174                  * reads and writes in an object.  The makes_rpc checks here
2175                  * would be redundant if we were getting read/write work items
2176                  * instead of objects.  we don't want send_oap_rpc to drain a
2177                  * partial read pending queue when we're given this object to
2178                  * do io on writes while there are cache waiters */
2179                 osc_object_lock(osc);
2180                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2181                         rc = osc_send_write_rpc(env, cli, osc);
2182                         if (rc < 0) {
2183                                 CERROR("Write request failed with %d\n", rc);
2184
2185                                 /* osc_send_write_rpc failed, mostly because of
2186                                  * memory pressure.
2187                                  *
2188                                  * It can't break here, because if:
2189                                  *  - a page was submitted by osc_io_submit, so
2190                                  *    page locked;
2191                                  *  - no request in flight
2192                                  *  - no subsequent request
2193                                  * The system will be in live-lock state,
2194                                  * because there is no chance to call
2195                                  * osc_io_unplug() and osc_check_rpcs() any
2196                                  * more. pdflush can't help in this case,
2197                                  * because it might be blocked at grabbing
2198                                  * the page lock as we mentioned.
2199                                  *
2200                                  * Anyway, continue to drain pages. */
2201                                 /* break; */
2202                         }
2203                 }
2204                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2205                         rc = osc_send_read_rpc(env, cli, osc);
2206                         if (rc < 0)
2207                                 CERROR("Read request failed with %d\n", rc);
2208                 }
2209                 osc_object_unlock(osc);
2210
2211                 osc_list_maint(cli, osc);
2212                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2213                 cl_object_put(env, obj);
2214
2215                 spin_lock(&cli->cl_loi_list_lock);
2216         }
2217 }
2218
2219 int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2220                    struct osc_object *osc, int async)
2221 {
2222         int rc = 0;
2223
2224         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2225                 return 0;
2226
2227         if (!async) {
2228                 spin_lock(&cli->cl_loi_list_lock);
2229                 osc_check_rpcs(env, cli);
2230                 spin_unlock(&cli->cl_loi_list_lock);
2231         } else {
2232                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2233                 LASSERT(cli->cl_writeback_work != NULL);
2234                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2235         }
2236         return rc;
2237 }
2238 EXPORT_SYMBOL(osc_io_unplug0);
2239
2240 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2241                         struct cl_page *page, loff_t offset)
2242 {
2243         struct obd_export     *exp = osc_export(osc);
2244         struct osc_async_page *oap = &ops->ops_oap;
2245         struct page           *vmpage = page->cp_vmpage;
2246         ENTRY;
2247
2248         if (!page)
2249                 return cfs_size_round(sizeof(*oap));
2250
2251         oap->oap_magic = OAP_MAGIC;
2252         oap->oap_cli = &exp->exp_obd->u.cli;
2253         oap->oap_obj = osc;
2254
2255         oap->oap_page = vmpage;
2256         oap->oap_obj_off = offset;
2257         LASSERT(!(offset & ~PAGE_MASK));
2258
2259         /* Count of transient (direct i/o) pages is always stable by the time
2260          * they're submitted.  Setting this here lets us avoid calling
2261          * cl_page_clip later to set this.
2262          */
2263         if (page->cp_type == CPT_TRANSIENT)
2264                 oap->oap_async_flags |= ASYNC_COUNT_STABLE|ASYNC_URGENT|
2265                                         ASYNC_READY;
2266
2267         INIT_LIST_HEAD(&oap->oap_pending_item);
2268         INIT_LIST_HEAD(&oap->oap_rpc_item);
2269
2270         spin_lock_init(&oap->oap_lock);
2271         CDEBUG(D_INFO, "oap %p vmpage %p obj off %llu\n",
2272                oap, vmpage, oap->oap_obj_off);
2273         RETURN(0);
2274 }
2275 EXPORT_SYMBOL(osc_prep_async_page);
2276
2277 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2278                        struct osc_page *ops, cl_commit_cbt cb)
2279 {
2280         struct osc_io *oio = osc_env_io(env);
2281         struct osc_extent     *ext = NULL;
2282         struct osc_async_page *oap = &ops->ops_oap;
2283         struct client_obd     *cli = oap->oap_cli;
2284         struct osc_object     *osc = oap->oap_obj;
2285         struct pagevec        *pvec = &osc_env_info(env)->oti_pagevec;
2286         pgoff_t index;
2287         unsigned int tmp;
2288         unsigned int grants = 0;
2289         u32    brw_flags = OBD_BRW_ASYNC;
2290         int    cmd = OBD_BRW_WRITE;
2291         int    need_release = 0;
2292         int    rc = 0;
2293         ENTRY;
2294
2295         if (oap->oap_magic != OAP_MAGIC)
2296                 RETURN(-EINVAL);
2297
2298         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2299                 RETURN(-EIO);
2300
2301         if (!list_empty(&oap->oap_pending_item) ||
2302             !list_empty(&oap->oap_rpc_item))
2303                 RETURN(-EBUSY);
2304
2305         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2306         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2307         if (io->ci_noquota) {
2308                 brw_flags |= OBD_BRW_NOQUOTA;
2309                 cmd |= OBD_BRW_NOQUOTA;
2310         }
2311
2312         if (oio->oi_cap_sys_resource) {
2313                 brw_flags |= OBD_BRW_SYS_RESOURCE;
2314                 cmd |= OBD_BRW_SYS_RESOURCE;
2315         }
2316
2317         /* check if the file's owner/group is over quota */
2318         if (!io->ci_noquota) {
2319                 struct cl_object *obj;
2320                 struct cl_attr   *attr;
2321                 unsigned int qid[LL_MAXQUOTAS];
2322
2323                 obj = cl_object_top(&osc->oo_cl);
2324                 attr = &osc_env_info(env)->oti_attr;
2325
2326                 cl_object_attr_lock(obj);
2327                 rc = cl_object_attr_get(env, obj, attr);
2328                 cl_object_attr_unlock(obj);
2329
2330                 qid[USRQUOTA] = attr->cat_uid;
2331                 qid[GRPQUOTA] = attr->cat_gid;
2332                 qid[PRJQUOTA] = attr->cat_projid;
2333                 /*
2334                  * if EDQUOT returned for root, we double check
2335                  * if root squash enabled or not updated from server side.
2336                  * without root squash, we should bypass quota for root.
2337                  */
2338                 if (rc == 0 && osc_quota_chkdq(cli, qid) == -EDQUOT) {
2339                         if (oio->oi_cap_sys_resource &&
2340                             !cli->cl_root_squash) {
2341                                 io->ci_noquota = 1;
2342                                 rc = 0;
2343                         } else {
2344                                 rc = -EDQUOT;
2345                         }
2346                 }
2347                 if (rc)
2348                         RETURN(rc);
2349         }
2350
2351         oap->oap_cmd = cmd;
2352         oap->oap_page_off = ops->ops_from;
2353         oap->oap_count = ops->ops_to - ops->ops_from + 1;
2354         /* No need to hold a lock here,
2355          * since this page is not in any list yet. */
2356         oap->oap_async_flags = 0;
2357         oap->oap_brw_flags = brw_flags;
2358
2359         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2360                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2361
2362         index = osc_index(oap2osc(oap));
2363
2364         /* Add this page into extent by the following steps:
2365          * 1. if there exists an active extent for this IO, mostly this page
2366          *    can be added to the active extent and sometimes we need to
2367          *    expand extent to accomodate this page;
2368          * 2. otherwise, a new extent will be allocated. */
2369
2370         ext = oio->oi_active;
2371         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2372                 /* one chunk plus extent overhead must be enough to write this
2373                  * page */
2374                 grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2375                 if (ext->oe_end >= index)
2376                         grants = 0;
2377
2378                 /* it doesn't need any grant to dirty this page */
2379                 spin_lock(&cli->cl_loi_list_lock);
2380                 rc = osc_enter_cache_try(cli, oap, grants);
2381                 if (rc == 0) { /* try failed */
2382                         grants = 0;
2383                         need_release = 1;
2384                 } else if (ext->oe_end < index) {
2385                         tmp = grants;
2386                         /* try to expand this extent */
2387                         rc = osc_extent_expand(ext, index, &tmp);
2388                         if (rc < 0) {
2389                                 need_release = 1;
2390                                 /* don't free reserved grant */
2391                         } else {
2392                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2393                                                 "expanded for %lu.\n", index);
2394                                 osc_unreserve_grant_nolock(cli, grants, tmp);
2395                                 grants = 0;
2396                         }
2397                 }
2398                 spin_unlock(&cli->cl_loi_list_lock);
2399                 rc = 0;
2400         } else if (ext != NULL) {
2401                 /* index is located outside of active extent */
2402                 need_release = 1;
2403         }
2404         if (need_release) {
2405                 osc_extent_release(env, ext);
2406                 oio->oi_active = NULL;
2407                 ext = NULL;
2408         }
2409
2410         if (ext == NULL) {
2411                 tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2412
2413                 /* try to find new extent to cover this page */
2414                 LASSERT(oio->oi_active == NULL);
2415                 /* we may have allocated grant for this page if we failed
2416                  * to expand the previous active extent. */
2417                 LASSERT(ergo(grants > 0, grants >= tmp));
2418
2419                 rc = 0;
2420                 if (grants == 0) {
2421                         /* We haven't allocated grant for this page, and we
2422                          * must not hold a page lock while we do enter_cache,
2423                          * so we must mark dirty & unlock any pages in the
2424                          * write commit pagevec. */
2425                         if (pagevec_count(pvec)) {
2426                                 cb(env, io, pvec);
2427                                 pagevec_reinit(pvec);
2428                         }
2429                         rc = osc_enter_cache(env, cli, oap, tmp);
2430                         if (rc == 0)
2431                                 grants = tmp;
2432                 }
2433
2434                 tmp = grants;
2435                 if (rc == 0) {
2436                         ext = osc_extent_find(env, osc, index, &tmp);
2437                         if (IS_ERR(ext)) {
2438                                 LASSERT(tmp == grants);
2439                                 osc_exit_cache(cli, oap);
2440                                 rc = PTR_ERR(ext);
2441                                 ext = NULL;
2442                         } else {
2443                                 oio->oi_active = ext;
2444                         }
2445                 }
2446                 if (grants > 0)
2447                         osc_unreserve_grant(cli, grants, tmp);
2448         }
2449
2450         LASSERT(ergo(rc == 0, ext != NULL));
2451         if (ext != NULL) {
2452                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2453                          ext, "index = %lu.\n", index);
2454                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2455
2456                 osc_object_lock(osc);
2457                 if (ext->oe_nr_pages == 0)
2458                         ext->oe_srvlock = ops->ops_srvlock;
2459                 else
2460                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2461                 ++ext->oe_nr_pages;
2462                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2463                 osc_object_unlock(osc);
2464
2465                 if (!ext->oe_layout_version)
2466                         ext->oe_layout_version = io->ci_layout_version;
2467         }
2468
2469         RETURN(rc);
2470 }
2471
2472 int osc_teardown_async_page(const struct lu_env *env,
2473                             struct osc_object *obj, struct osc_page *ops)
2474 {
2475         struct osc_async_page *oap = &ops->ops_oap;
2476         int rc = 0;
2477         ENTRY;
2478
2479         LASSERT(oap->oap_magic == OAP_MAGIC);
2480
2481         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2482                oap, ops, osc_index(oap2osc(oap)));
2483
2484         if (!list_empty(&oap->oap_rpc_item)) {
2485                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2486                 rc = -EBUSY;
2487         } else if (!list_empty(&oap->oap_pending_item)) {
2488                 struct osc_extent *ext = NULL;
2489
2490                 osc_object_lock(obj);
2491                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2492                 osc_object_unlock(obj);
2493                 /* only truncated pages are allowed to be taken out.
2494                  * See osc_extent_truncate() and osc_cache_truncate_start()
2495                  * for details. */
2496                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2497                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2498                                         osc_index(oap2osc(oap)));
2499                         rc = -EBUSY;
2500                 }
2501                 if (ext != NULL)
2502                         osc_extent_put(env, ext);
2503         }
2504         RETURN(rc);
2505 }
2506
2507 /**
2508  * This is called when a page is picked up by kernel to write out.
2509  *
2510  * We should find out the corresponding extent and add the whole extent
2511  * into urgent list. The extent may be being truncated or used, handle it
2512  * carefully.
2513  */
2514 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2515                          struct osc_page *ops)
2516 {
2517         struct osc_extent *ext   = NULL;
2518         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2519         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2520         pgoff_t            index = osc_index(ops);
2521         struct osc_async_page *oap = &ops->ops_oap;
2522         bool unplug = false;
2523         int rc = 0;
2524         ENTRY;
2525
2526         osc_object_lock(obj);
2527         ext = osc_extent_lookup(obj, index);
2528         if (ext == NULL) {
2529                 osc_extent_tree_dump(D_ERROR, obj);
2530                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2531         }
2532
2533         switch (ext->oe_state) {
2534         case OES_RPC:
2535         case OES_LOCK_DONE:
2536                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2537                 LASSERT(0);
2538                 break;
2539         case OES_LOCKING:
2540                 /* If we know this extent is being written out, we should abort
2541                  * so that the writer can make this page ready. Otherwise, there
2542                  * exists a deadlock problem because other process can wait for
2543                  * page writeback bit holding page lock; and meanwhile in
2544                  * vvp_page_make_ready(), we need to grab page lock before
2545                  * really sending the RPC. */
2546         case OES_TRUNC:
2547                 /* race with truncate, page will be redirtied */
2548         case OES_ACTIVE:
2549                 /* The extent is active so we need to abort and let the caller
2550                  * re-dirty the page. If we continued on here, and we were the
2551                  * one making the extent active, we could deadlock waiting for
2552                  * the page writeback to clear but it won't because the extent
2553                  * is active and won't be written out. */
2554                 GOTO(out, rc = -EAGAIN);
2555         default:
2556                 break;
2557         }
2558
2559         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2560         if (rc)
2561                 GOTO(out, rc);
2562
2563         spin_lock(&oap->oap_lock);
2564         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2565         spin_unlock(&oap->oap_lock);
2566
2567         if (current->flags & PF_MEMALLOC)
2568                 ext->oe_memalloc = 1;
2569
2570         ext->oe_urgent = 1;
2571         if (ext->oe_state == OES_CACHE) {
2572                 OSC_EXTENT_DUMP(D_CACHE, ext,
2573                                 "flush page %p make it urgent.\n", oap);
2574                 if (list_empty(&ext->oe_link))
2575                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2576                 unplug = true;
2577         }
2578         rc = 0;
2579         EXIT;
2580
2581 out:
2582         osc_object_unlock(obj);
2583         osc_extent_put(env, ext);
2584         if (unplug)
2585                 osc_io_unplug_async(env, osc_cli(obj), obj);
2586         return rc;
2587 }
2588
2589 int osc_queue_sync_pages(const struct lu_env *env, struct cl_io *io,
2590                          struct osc_object *obj, struct list_head *list,
2591                          int brw_flags)
2592 {
2593         struct client_obd     *cli = osc_cli(obj);
2594         struct osc_extent     *ext;
2595         struct osc_async_page *oap;
2596         int     page_count = 0;
2597         int     mppr       = cli->cl_max_pages_per_rpc;
2598         bool    can_merge   = true;
2599         pgoff_t start      = CL_PAGE_EOF;
2600         pgoff_t end        = 0;
2601         ENTRY;
2602
2603         list_for_each_entry(oap, list, oap_pending_item) {
2604                 struct osc_page *opg = oap2osc_page(oap);
2605                 pgoff_t index = osc_index(opg);
2606
2607                 if (index > end)
2608                         end = index;
2609                 if (index < start)
2610                         start = index;
2611                 ++page_count;
2612                 mppr <<= (page_count > mppr);
2613
2614                 if (unlikely(opg->ops_from > 0 ||
2615                              opg->ops_to < PAGE_SIZE - 1))
2616                         can_merge = false;
2617         }
2618
2619         ext = osc_extent_alloc(obj);
2620         if (ext == NULL) {
2621                 struct osc_async_page *tmp;
2622
2623                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2624                         list_del_init(&oap->oap_pending_item);
2625                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2626                 }
2627                 RETURN(-ENOMEM);
2628         }
2629
2630         ext->oe_rw = !!(brw_flags & OBD_BRW_READ);
2631         ext->oe_sync = 1;
2632         ext->oe_no_merge = !can_merge;
2633         ext->oe_urgent = 1;
2634         ext->oe_start = start;
2635         ext->oe_end = ext->oe_max_end = end;
2636         ext->oe_obj = obj;
2637         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2638         ext->oe_ndelay = !!(brw_flags & OBD_BRW_NDELAY);
2639         ext->oe_dio = !!(brw_flags & OBD_BRW_NOCACHE);
2640         if (ext->oe_dio && !ext->oe_rw) { /* direct io write */
2641                 int grants;
2642                 int ppc;
2643
2644                 ppc = 1 << (cli->cl_chunkbits - PAGE_SHIFT);
2645                 grants = cli->cl_grant_extent_tax;
2646                 grants += (1 << cli->cl_chunkbits) *
2647                         ((page_count + ppc - 1) / ppc);
2648
2649                 CDEBUG(D_CACHE, "requesting %d bytes grant\n", grants);
2650                 spin_lock(&cli->cl_loi_list_lock);
2651                 if (osc_reserve_grant(cli, grants) == 0) {
2652                         list_for_each_entry(oap, list, oap_pending_item) {
2653                                 osc_consume_write_grant(cli,
2654                                                         &oap->oap_brw_page);
2655                         }
2656                         atomic_long_add(page_count, &obd_dirty_pages);
2657                         osc_unreserve_grant_nolock(cli, grants, 0);
2658                         ext->oe_grants = grants;
2659                 } else {
2660                         /* We cannot report ENOSPC correctly if we do parallel
2661                          * DIO (async RPC submission), so turn off parallel dio
2662                          * if there is not sufficient grant available.  This
2663                          * makes individual RPCs synchronous.
2664                          */
2665                         io->ci_parallel_dio = false;
2666                         CDEBUG(D_CACHE,
2667                         "not enough grant available, switching to sync for this i/o\n");
2668                 }
2669                 spin_unlock(&cli->cl_loi_list_lock);
2670                 osc_update_next_shrink(cli);
2671         }
2672
2673         ext->oe_is_rdma_only = !!(brw_flags & OBD_BRW_RDMA_ONLY);
2674         ext->oe_nr_pages = page_count;
2675         ext->oe_mppr = mppr;
2676         list_splice_init(list, &ext->oe_pages);
2677         ext->oe_layout_version = io->ci_layout_version;
2678
2679         osc_object_lock(obj);
2680         /* Reuse the initial refcount for RPC, don't drop it */
2681         osc_extent_state_set(ext, OES_LOCK_DONE);
2682         if (!ext->oe_rw) { /* write */
2683                 if (!ext->oe_srvlock && !ext->oe_dio) {
2684                         /* The most likely case here is from lack of grants
2685                          * so we are either out of quota or out of space.
2686                          * Since this means we are holding locks across
2687                          * potentially multi-striped IO, we must send out
2688                          * everything out instantly to avoid prolonged
2689                          * waits resulting in lock eviction (likely since
2690                          * the extended wait in osc_cache_enter() did not
2691                          * yield any additional grant due to a timeout.
2692                          * LU-13131 */
2693                         ext->oe_hp = 1;
2694                         list_add_tail(&ext->oe_link, &obj->oo_hp_exts);
2695                 } else {
2696                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2697                 }
2698                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2699         } else {
2700                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2701                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2702         }
2703         osc_object_unlock(obj);
2704
2705         osc_io_unplug_async(env, cli, obj);
2706         RETURN(0);
2707 }
2708
2709 /**
2710  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2711  */
2712 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2713                              __u64 size, struct osc_extent **extp)
2714 {
2715         struct client_obd *cli = osc_cli(obj);
2716         struct osc_extent *ext;
2717         struct osc_extent *waiting = NULL;
2718         pgoff_t index;
2719         LIST_HEAD(list);
2720         int result = 0;
2721         bool partial;
2722         ENTRY;
2723
2724         /* pages with index greater or equal to index will be truncated. */
2725         index = cl_index(osc2cl(obj), size);
2726         partial = size > cl_offset(osc2cl(obj), index);
2727
2728 again:
2729         osc_object_lock(obj);
2730         ext = osc_extent_search(obj, index);
2731         if (ext == NULL)
2732                 ext = first_extent(obj);
2733         else if (ext->oe_end < index)
2734                 ext = next_extent(ext);
2735         while (ext != NULL) {
2736                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2737
2738                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2739                         /* if ext is in urgent state, it means there must exist
2740                          * a page already having been flushed by write_page().
2741                          * We have to wait for this extent because we can't
2742                          * truncate that page. */
2743                         OSC_EXTENT_DUMP(D_CACHE, ext,
2744                                         "waiting for busy extent\n");
2745                         waiting = osc_extent_get(ext);
2746                         break;
2747                 }
2748
2749                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:%llu.\n", size);
2750
2751                 osc_extent_get(ext);
2752                 if (ext->oe_state == OES_ACTIVE) {
2753                         /* though we grab inode mutex for write path, but we
2754                          * release it before releasing extent(in osc_io_end()),
2755                          * so there is a race window that an extent is still
2756                          * in OES_ACTIVE when truncate starts. */
2757                         LASSERT(!ext->oe_trunc_pending);
2758                         ext->oe_trunc_pending = 1;
2759                 } else {
2760                         EASSERT(ext->oe_state == OES_CACHE, ext);
2761                         osc_extent_state_set(ext, OES_TRUNC);
2762                         osc_update_pending(obj, OBD_BRW_WRITE,
2763                                            -ext->oe_nr_pages);
2764                 }
2765                 /* This extent could be on the full extents list, that's OK */
2766                 EASSERT(!ext->oe_hp && !ext->oe_urgent, ext);
2767                 if (!list_empty(&ext->oe_link))
2768                         list_move_tail(&ext->oe_link, &list);
2769                 else
2770                         list_add_tail(&ext->oe_link, &list);
2771
2772                 ext = next_extent(ext);
2773         }
2774         osc_object_unlock(obj);
2775
2776         osc_list_maint(cli, obj);
2777
2778         while ((ext = list_first_entry_or_null(&list,
2779                                                struct osc_extent,
2780                                                oe_link)) != NULL) {
2781                 int rc;
2782
2783                 list_del_init(&ext->oe_link);
2784
2785                 /* extent may be in OES_ACTIVE state because inode mutex
2786                  * is released before osc_io_end() in file write case */
2787                 if (ext->oe_state != OES_TRUNC)
2788                         osc_extent_wait(env, ext, OES_TRUNC);
2789
2790                 rc = osc_extent_truncate(ext, index, partial);
2791                 if (rc < 0) {
2792                         if (result == 0)
2793                                 result = rc;
2794
2795                         OSC_EXTENT_DUMP(D_ERROR, ext,
2796                                         "truncate error %d\n", rc);
2797                 } else if (ext->oe_nr_pages == 0) {
2798                         osc_extent_remove(ext);
2799                 } else {
2800                         /* this must be an overlapped extent which means only
2801                          * part of pages in this extent have been truncated.
2802                          */
2803                         EASSERTF(ext->oe_start <= index, ext,
2804                                  "trunc index = %lu/%d.\n", index, partial);
2805                         /* fix index to skip this partially truncated extent */
2806                         index = ext->oe_end + 1;
2807                         partial = false;
2808
2809                         /* we need to hold this extent in OES_TRUNC state so
2810                          * that no writeback will happen. This is to avoid
2811                          * BUG 17397.
2812                          * Only partial truncate can reach here, if @size is
2813                          * not zero, the caller should provide a valid @extp. */
2814                         LASSERT(*extp == NULL);
2815                         *extp = osc_extent_get(ext);
2816                         OSC_EXTENT_DUMP(D_CACHE, ext,
2817                                         "trunc at %llu\n", size);
2818                 }
2819                 osc_extent_put(env, ext);
2820         }
2821         if (waiting != NULL) {
2822                 int rc;
2823
2824                 /* ignore the result of osc_extent_wait the write initiator
2825                  * should take care of it. */
2826                 rc = osc_extent_wait(env, waiting, OES_INV);
2827                 if (rc < 0)
2828                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2829
2830                 osc_extent_put(env, waiting);
2831                 waiting = NULL;
2832                 goto again;
2833         }
2834         RETURN(result);
2835 }
2836 EXPORT_SYMBOL(osc_cache_truncate_start);
2837
2838 /**
2839  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2840  */
2841 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2842 {
2843         if (ext != NULL) {
2844                 struct osc_object *obj = ext->oe_obj;
2845                 bool unplug = false;
2846
2847                 EASSERT(ext->oe_nr_pages > 0, ext);
2848                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2849                 EASSERT(!ext->oe_urgent, ext);
2850
2851                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2852                 osc_object_lock(obj);
2853                 osc_extent_state_set(ext, OES_CACHE);
2854                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2855                         ext->oe_urgent = 1;
2856                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2857                         unplug = true;
2858                 }
2859                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2860                 osc_object_unlock(obj);
2861                 osc_extent_put(env, ext);
2862
2863                 if (unplug)
2864                         osc_io_unplug_async(env, osc_cli(obj), obj);
2865         }
2866 }
2867
2868 /**
2869  * Wait for extents in a specific range to be written out.
2870  * The caller must have called osc_cache_writeback_range() to issue IO
2871  * otherwise it will take a long time for this function to finish.
2872  *
2873  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2874  * nobody else can dirty this range of file while we're waiting for
2875  * extents to be written.
2876  */
2877 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2878                          pgoff_t start, pgoff_t end)
2879 {
2880         struct osc_extent *ext;
2881         pgoff_t index = start;
2882         int     result = 0;
2883         ENTRY;
2884
2885 again:
2886         osc_object_lock(obj);
2887         ext = osc_extent_search(obj, index);
2888         if (ext == NULL)
2889                 ext = first_extent(obj);
2890         else if (ext->oe_end < index)
2891                 ext = next_extent(ext);
2892         while (ext != NULL) {
2893                 int rc;
2894
2895                 if (ext->oe_start > end)
2896                         break;
2897
2898                 if (!ext->oe_fsync_wait) {
2899                         ext = next_extent(ext);
2900                         continue;
2901                 }
2902
2903                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2904                              ext->oe_hp || ext->oe_urgent), ext);
2905                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2906                              !ext->oe_hp && ext->oe_urgent), ext);
2907
2908                 index = ext->oe_end + 1;
2909                 osc_extent_get(ext);
2910                 osc_object_unlock(obj);
2911
2912                 rc = osc_extent_wait(env, ext, OES_INV);
2913                 if (result == 0)
2914                         result = rc;
2915                 osc_extent_put(env, ext);
2916                 goto again;
2917         }
2918         osc_object_unlock(obj);
2919
2920         OSC_IO_DEBUG(obj, "sync file range.\n");
2921         RETURN(result);
2922 }
2923 EXPORT_SYMBOL(osc_cache_wait_range);
2924
2925 /**
2926  * Called to write out a range of osc object.
2927  *
2928  * @hp     : should be set this is caused by lock cancel;
2929  * @discard: is set if dirty pages should be dropped - file will be deleted or
2930  *         truncated, this implies there is no partially discarding extents.
2931  *
2932  * Return how many pages will be issued, or error code if error occurred.
2933  */
2934 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2935                               pgoff_t start, pgoff_t end, int hp, int discard)
2936 {
2937         struct osc_extent *ext;
2938         LIST_HEAD(discard_list);
2939         bool unplug = false;
2940         int result = 0;
2941         ENTRY;
2942
2943         osc_object_lock(obj);
2944         ext = osc_extent_search(obj, start);
2945         if (ext == NULL)
2946                 ext = first_extent(obj);
2947         else if (ext->oe_end < start)
2948                 ext = next_extent(ext);
2949         while (ext != NULL) {
2950                 if (ext->oe_start > end)
2951                         break;
2952
2953                 ext->oe_fsync_wait = 1;
2954                 switch (ext->oe_state) {
2955                 case OES_CACHE:
2956                         result += ext->oe_nr_pages;
2957                         if (!discard) {
2958                                 struct list_head *list = NULL;
2959                                 if (hp) {
2960                                         EASSERT(!ext->oe_hp, ext);
2961                                         ext->oe_hp = 1;
2962                                         list = &obj->oo_hp_exts;
2963                                 } else if (!ext->oe_urgent && !ext->oe_hp) {
2964                                         ext->oe_urgent = 1;
2965                                         list = &obj->oo_urgent_exts;
2966                                 }
2967                                 if (list != NULL)
2968                                         list_move_tail(&ext->oe_link, list);
2969                                 unplug = true;
2970                         } else {
2971                                 struct client_obd *cli = osc_cli(obj);
2972                                 int pcc_bits = cli->cl_chunkbits - PAGE_SHIFT;
2973                                 pgoff_t align_by = (1 << pcc_bits);
2974                                 pgoff_t a_start = round_down(start, align_by);
2975                                 pgoff_t a_end = round_up(end, align_by);
2976
2977                                 /* overflow case */
2978                                 if (end && !a_end)
2979                                         a_end = CL_PAGE_EOF;
2980                                 /* the only discarder is lock cancelling, so
2981                                  * [start, end], aligned by chunk size, must
2982                                  * contain this extent */
2983                                 LASSERTF(ext->oe_start >= a_start &&
2984                                          ext->oe_end <= a_end,
2985                                          "ext [%lu, %lu] reg [%lu, %lu] "
2986                                          "orig [%lu %lu] align %lu bits "
2987                                          "%d\n", ext->oe_start, ext->oe_end,
2988                                          a_start, a_end, start, end,
2989                                          align_by, pcc_bits);
2990                                 osc_extent_state_set(ext, OES_LOCKING);
2991                                 ext->oe_owner = current;
2992                                 list_move_tail(&ext->oe_link,
2993                                                    &discard_list);
2994                                 osc_update_pending(obj, OBD_BRW_WRITE,
2995                                                    -ext->oe_nr_pages);
2996                         }
2997                         break;
2998                 case OES_ACTIVE:
2999                         /* It's pretty bad to wait for ACTIVE extents, because
3000                          * we don't know how long we will wait for it to be
3001                          * flushed since it may be blocked at awaiting more
3002                          * grants. We do this for the correctness of fsync. */
3003                         LASSERT(hp == 0 && discard == 0);
3004                         ext->oe_urgent = 1;
3005                         break;
3006                 case OES_TRUNC:
3007                         /* this extent is being truncated, can't do anything
3008                          * for it now. it will be set to urgent after truncate
3009                          * is finished in osc_cache_truncate_end(). */
3010                 default:
3011                         break;
3012                 }
3013                 ext = next_extent(ext);
3014         }
3015         osc_object_unlock(obj);
3016
3017         LASSERT(ergo(!discard, list_empty(&discard_list)));
3018         if (!list_empty(&discard_list)) {
3019                 struct osc_extent *tmp;
3020                 int rc;
3021
3022                 osc_list_maint(osc_cli(obj), obj);
3023                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
3024                         list_del_init(&ext->oe_link);
3025                         EASSERT(ext->oe_state == OES_LOCKING, ext);
3026
3027                         /* Discard caching pages. We don't actually write this
3028                          * extent out but we complete it as if we did. */
3029                         rc = osc_extent_make_ready(env, ext);
3030                         if (unlikely(rc < 0)) {
3031                                 OSC_EXTENT_DUMP(D_ERROR, ext,
3032                                                 "make_ready returned %d\n", rc);
3033                                 if (result >= 0)
3034                                         result = rc;
3035                         }
3036
3037                         /* finish the extent as if the pages were sent */
3038                         osc_extent_finish(env, ext, 0, 0);
3039                 }
3040         }
3041
3042         if (unplug)
3043                 osc_io_unplug(env, osc_cli(obj), obj);
3044
3045         if (hp || discard) {
3046                 int rc;
3047                 rc = osc_cache_wait_range(env, obj, start, end);
3048                 if (result >= 0 && rc < 0)
3049                         result = rc;
3050         }
3051
3052         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
3053         RETURN(result);
3054 }
3055 EXPORT_SYMBOL(osc_cache_writeback_range);
3056
3057 /**
3058  * Returns a list of pages by a given [start, end] of \a obj.
3059  *
3060  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
3061  * crucial in the face of [offset, EOF] locks.
3062  *
3063  * Return at least one page in @queue unless there is no covered page.
3064  */
3065 bool osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3066                           struct osc_object *osc, pgoff_t start, pgoff_t end,
3067                           osc_page_gang_cbt cb, void *cbdata)
3068 {
3069         struct osc_page *ops;
3070         struct pagevec  *pagevec;
3071         void            **pvec;
3072         pgoff_t         idx;
3073         unsigned int    nr;
3074         unsigned int    i;
3075         unsigned int    j;
3076         bool            res = true;
3077         bool            tree_lock = true;
3078         ENTRY;
3079
3080         idx = start;
3081         pvec = osc_env_info(env)->oti_pvec;
3082         pagevec = &osc_env_info(env)->oti_pagevec;
3083         ll_pagevec_init(pagevec, 0);
3084         spin_lock(&osc->oo_tree_lock);
3085         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3086                                             idx, OTI_PVEC_SIZE)) > 0) {
3087                 struct cl_page *page;
3088                 bool end_of_region = false;
3089
3090                 for (i = 0, j = 0; i < nr; ++i) {
3091                         ops = pvec[i];
3092                         pvec[i] = NULL;
3093
3094                         idx = osc_index(ops);
3095                         if (idx > end) {
3096                                 end_of_region = true;
3097                                 break;
3098                         }
3099
3100                         page = ops->ops_cl.cpl_page;
3101                         LASSERT(page->cp_type == CPT_CACHEABLE);
3102                         if (page->cp_state == CPS_FREEING)
3103                                 continue;
3104
3105                         cl_page_get(page);
3106                         lu_ref_add_atomic(&page->cp_reference,
3107                                           "gang_lookup", current);
3108                         pvec[j++] = ops;
3109                 }
3110                 ++idx;
3111
3112                 /*
3113                  * Here a delicate locking dance is performed. Current thread
3114                  * holds a reference to a page, but has to own it before it
3115                  * can be placed into queue. Owning implies waiting, so
3116                  * radix-tree lock is to be released. After a wait one has to
3117                  * check that pages weren't truncated (cl_page_own() returns
3118                  * error in the latter case).
3119                  */
3120                 spin_unlock(&osc->oo_tree_lock);
3121                 tree_lock = false;
3122
3123                 res = (*cb)(env, io, pvec, j, cbdata);
3124
3125                 for (i = 0; i < j; ++i) {
3126                         ops = pvec[i];
3127                         page = ops->ops_cl.cpl_page;
3128                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3129                         cl_pagevec_put(env, page, pagevec);
3130                 }
3131                 pagevec_release(pagevec);
3132
3133                 if (nr < OTI_PVEC_SIZE || end_of_region)
3134                         break;
3135
3136                 if (!res)
3137                         break;
3138
3139                 OBD_FAIL_TIMEOUT(OBD_FAIL_OSC_SLOW_PAGE_EVICT,
3140                                  cfs_fail_val ?: 20);
3141
3142                 if (io->ci_type == CIT_MISC &&
3143                     io->u.ci_misc.lm_next_rpc_time &&
3144                     ktime_get_seconds() > io->u.ci_misc.lm_next_rpc_time) {
3145                         osc_send_empty_rpc(osc, idx << PAGE_SHIFT);
3146                         io->u.ci_misc.lm_next_rpc_time = ktime_get_seconds() +
3147                                                          5 * obd_timeout / 16;
3148                 }
3149
3150                 if (need_resched())
3151                         cond_resched();
3152
3153                 spin_lock(&osc->oo_tree_lock);
3154                 tree_lock = true;
3155         }
3156         if (tree_lock)
3157                 spin_unlock(&osc->oo_tree_lock);
3158         RETURN(res);