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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.sun.com/software/products/lustre/docs/GPLv2.pdf
19  *
20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21  * CA 95054 USA or visit www.sun.com if you need additional information or
22  * have any questions.
23  *
24  * GPL HEADER END
25  */
26 /*
27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
28  * Use is subject to license terms.
29  *
30  * Copyright (c) 2012, Intel Corporation.
31  *
32  */
33 /*
34  * This file is part of Lustre, http://www.lustre.org/
35  * Lustre is a trademark of Sun Microsystems, Inc.
36  *
37  * osc cache management.
38  *
39  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
40  */
41
42 #define DEBUG_SUBSYSTEM S_OSC
43
44 #include "osc_cl_internal.h"
45 #include "osc_internal.h"
46
47 static int extent_debug; /* set it to be true for more debug */
48
49 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
50 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
51                            int state);
52 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
53                               struct osc_async_page *oap, int sent, int rc);
54 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
55                           int cmd);
56 static int osc_refresh_count(const struct lu_env *env,
57                              struct osc_async_page *oap, int cmd);
58 static int osc_io_unplug_async(const struct lu_env *env,
59                                struct client_obd *cli, struct osc_object *osc);
60 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
61                            unsigned int lost_grant);
62
63 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
64                                   const char *func, int line);
65 #define osc_extent_tree_dump(lvl, obj) \
66         osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
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 (ext->oe_intree)
78                 *buf++ = 'i';
79         if (ext->oe_srvlock)
80                 *buf++ = 's';
81         if (ext->oe_hp)
82                 *buf++ = 'h';
83         if (ext->oe_urgent)
84                 *buf++ = 'u';
85         if (ext->oe_memalloc)
86                 *buf++ = 'm';
87         if (ext->oe_trunc_pending)
88                 *buf++ = 't';
89         if (ext->oe_fsync_wait)
90                 *buf++ = 'Y';
91         *buf = 0;
92         return flags;
93 }
94
95 static inline char list_empty_marker(cfs_list_t *list)
96 {
97         return cfs_list_empty(list) ? '-' : '+';
98 }
99
100 #define EXTSTR       "[%lu -> %lu/%lu]"
101 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
102
103 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                           \
104         struct osc_extent *__ext = (extent);                                  \
105         const char *__str[] = OES_STRINGS;                                    \
106         char __buf[16];                                                       \
107                                                                               \
108         CDEBUG(lvl,                                                           \
109                 "extent %p@{" EXTSTR ", "                                     \
110                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
111                 /* ----- extent part 0 ----- */                               \
112                 __ext, EXTPARA(__ext),                                        \
113                 /* ----- part 1 ----- */                                      \
114                 cfs_atomic_read(&__ext->oe_refc),                             \
115                 cfs_atomic_read(&__ext->oe_users),                            \
116                 list_empty_marker(&__ext->oe_link),                           \
117                 __str[__ext->oe_state], ext_flags(__ext, __buf),              \
118                 __ext->oe_obj,                                                \
119                 /* ----- part 2 ----- */                                      \
120                 __ext->oe_grants, __ext->oe_nr_pages,                         \
121                 list_empty_marker(&__ext->oe_pages),                          \
122                 cfs_waitq_active(&__ext->oe_waitq) ? '+' : '-',               \
123                 __ext->oe_osclock, __ext->oe_mppr, __ext->oe_owner,           \
124                 /* ----- part 4 ----- */                                      \
125                 ## __VA_ARGS__);                                              \
126 } while (0)
127
128 #undef EASSERTF
129 #define EASSERTF(expr, ext, fmt, args...) do {                          \
130         if (!(expr)) {                                                  \
131                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);            \
132                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);            \
133                 LASSERT(expr);                                          \
134         }                                                                    \
135 } while (0)
136
137 #undef EASSERT
138 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
139
140 static inline struct osc_extent *rb_extent(struct rb_node *n)
141 {
142         if (n == NULL)
143                 return NULL;
144
145         return container_of(n, struct osc_extent, oe_node);
146 }
147
148 static inline struct osc_extent *next_extent(struct osc_extent *ext)
149 {
150         if (ext == NULL)
151                 return NULL;
152
153         LASSERT(ext->oe_intree);
154         return rb_extent(rb_next(&ext->oe_node));
155 }
156
157 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
158 {
159         if (ext == NULL)
160                 return NULL;
161
162         LASSERT(ext->oe_intree);
163         return rb_extent(rb_prev(&ext->oe_node));
164 }
165
166 static inline struct osc_extent *first_extent(struct osc_object *obj)
167 {
168         return rb_extent(rb_first(&obj->oo_root));
169 }
170
171 /* object must be locked by caller. */
172 static int osc_extent_sanity_check0(struct osc_extent *ext,
173                                     const char *func, const int line)
174 {
175         struct osc_object *obj = ext->oe_obj;
176         struct osc_async_page *oap;
177         int page_count;
178         int rc = 0;
179
180         if (!osc_object_is_locked(obj))
181                 GOTO(out, rc = 9);
182
183         if (ext->oe_state >= OES_STATE_MAX)
184                 GOTO(out, rc = 10);
185
186         if (cfs_atomic_read(&ext->oe_refc) <= 0)
187                 GOTO(out, rc = 20);
188
189         if (cfs_atomic_read(&ext->oe_refc) < cfs_atomic_read(&ext->oe_users))
190                 GOTO(out, rc = 30);
191
192         switch (ext->oe_state) {
193         case OES_INV:
194                 if (ext->oe_nr_pages > 0 || !cfs_list_empty(&ext->oe_pages))
195                         GOTO(out, rc = 35);
196                 GOTO(out, rc = 0);
197                 break;
198         case OES_ACTIVE:
199                 if (cfs_atomic_read(&ext->oe_users) == 0)
200                         GOTO(out, rc = 40);
201                 if (ext->oe_hp)
202                         GOTO(out, rc = 50);
203                 if (ext->oe_fsync_wait && !ext->oe_urgent)
204                         GOTO(out, rc = 55);
205                 break;
206         case OES_CACHE:
207                 if (ext->oe_grants == 0)
208                         GOTO(out, rc = 60);
209                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
210                         GOTO(out, rc = 65);
211         default:
212                 if (cfs_atomic_read(&ext->oe_users) > 0)
213                         GOTO(out, rc = 70);
214         }
215
216         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
217                 GOTO(out, rc = 80);
218
219         if (ext->oe_osclock == NULL && ext->oe_grants > 0)
220                 GOTO(out, rc = 90);
221
222         if (ext->oe_osclock) {
223                 struct cl_lock_descr *descr;
224                 descr = &ext->oe_osclock->cll_descr;
225                 if (!(descr->cld_start <= ext->oe_start &&
226                       descr->cld_end >= ext->oe_max_end))
227                         GOTO(out, rc = 100);
228         }
229
230         if (ext->oe_nr_pages > ext->oe_mppr)
231                 GOTO(out, rc = 105);
232
233         /* Do not verify page list if extent is in RPC. This is because an
234          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
235         if (ext->oe_state > OES_CACHE)
236                 GOTO(out, rc = 0);
237
238         if (!extent_debug)
239                 GOTO(out, rc = 0);
240
241         page_count = 0;
242         cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
243                 pgoff_t index = oap2cl_page(oap)->cp_index;
244                 ++page_count;
245                 if (index > ext->oe_end || index < ext->oe_start)
246                         GOTO(out, rc = 110);
247         }
248         if (page_count != ext->oe_nr_pages)
249                 GOTO(out, rc = 120);
250
251 out:
252         if (rc != 0)
253                 OSC_EXTENT_DUMP(D_ERROR, ext,
254                                 "%s:%d sanity check %p failed with rc = %d\n",
255                                 func, line, ext, rc);
256         return rc;
257 }
258
259 #define sanity_check_nolock(ext) \
260         osc_extent_sanity_check0(ext, __func__, __LINE__)
261
262 #define sanity_check(ext) ({                                                   \
263         int __res;                                                             \
264         osc_object_lock((ext)->oe_obj);                                        \
265         __res = sanity_check_nolock(ext);                                      \
266         osc_object_unlock((ext)->oe_obj);                                      \
267         __res;                                                                 \
268 })
269
270
271 /**
272  * sanity check - to make sure there is no overlapped extent in the tree.
273  */
274 static int osc_extent_is_overlapped(struct osc_object *obj,
275                                     struct osc_extent *ext)
276 {
277         struct osc_extent *tmp;
278
279         LASSERT(osc_object_is_locked(obj));
280
281         if (!extent_debug)
282                 return 0;
283
284         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
285                 if (tmp == ext)
286                         continue;
287                 if (tmp->oe_end >= ext->oe_start &&
288                     tmp->oe_start <= ext->oe_end)
289                         return 1;
290         }
291         return 0;
292 }
293
294 static void osc_extent_state_set(struct osc_extent *ext, int state)
295 {
296         LASSERT(osc_object_is_locked(ext->oe_obj));
297         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
298
299         /* Never try to sanity check a state changing extent :-) */
300         /* LASSERT(sanity_check_nolock(ext) == 0); */
301
302         /* TODO: validate the state machine */
303         ext->oe_state = state;
304         cfs_waitq_broadcast(&ext->oe_waitq);
305 }
306
307 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
308 {
309         struct osc_extent *ext;
310
311         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, CFS_ALLOC_STD);
312         if (ext == NULL)
313                 return NULL;
314
315         RB_CLEAR_NODE(&ext->oe_node);
316         ext->oe_obj = obj;
317         cfs_atomic_set(&ext->oe_refc, 1);
318         cfs_atomic_set(&ext->oe_users, 0);
319         CFS_INIT_LIST_HEAD(&ext->oe_link);
320         ext->oe_state = OES_INV;
321         CFS_INIT_LIST_HEAD(&ext->oe_pages);
322         cfs_waitq_init(&ext->oe_waitq);
323         ext->oe_osclock = NULL;
324
325         return ext;
326 }
327
328 static void osc_extent_free(struct osc_extent *ext)
329 {
330         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
331 }
332
333 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
334 {
335         LASSERT(cfs_atomic_read(&ext->oe_refc) >= 0);
336         cfs_atomic_inc(&ext->oe_refc);
337         return ext;
338 }
339
340 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
341 {
342         LASSERT(cfs_atomic_read(&ext->oe_refc) > 0);
343         if (cfs_atomic_dec_and_test(&ext->oe_refc)) {
344                 LASSERT(cfs_list_empty(&ext->oe_link));
345                 LASSERT(cfs_atomic_read(&ext->oe_users) == 0);
346                 LASSERT(ext->oe_state == OES_INV);
347                 LASSERT(!ext->oe_intree);
348
349                 if (ext->oe_osclock) {
350                         cl_lock_put(env, ext->oe_osclock);
351                         ext->oe_osclock = NULL;
352                 }
353                 osc_extent_free(ext);
354         }
355 }
356
357 /**
358  * osc_extent_put_trust() is a special version of osc_extent_put() when
359  * it's known that the caller is not the last user. This is to address the
360  * problem of lacking of lu_env ;-).
361  */
362 static void osc_extent_put_trust(struct osc_extent *ext)
363 {
364         LASSERT(cfs_atomic_read(&ext->oe_refc) > 1);
365         LASSERT(osc_object_is_locked(ext->oe_obj));
366         cfs_atomic_dec(&ext->oe_refc);
367 }
368
369 /**
370  * Return the extent which includes pgoff @index, or return the greatest
371  * previous extent in the tree.
372  */
373 static struct osc_extent *osc_extent_search(struct osc_object *obj,
374                                             pgoff_t index)
375 {
376         struct rb_node    *n = obj->oo_root.rb_node;
377         struct osc_extent *tmp, *p = NULL;
378
379         LASSERT(osc_object_is_locked(obj));
380         while (n != NULL) {
381                 tmp = rb_extent(n);
382                 if (index < tmp->oe_start) {
383                         n = n->rb_left;
384                 } else if (index > tmp->oe_end) {
385                         p = rb_extent(n);
386                         n = n->rb_right;
387                 } else {
388                         return tmp;
389                 }
390         }
391         return p;
392 }
393
394 /*
395  * Return the extent covering @index, otherwise return NULL.
396  * caller must have held object lock.
397  */
398 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
399                                             pgoff_t index)
400 {
401         struct osc_extent *ext;
402
403         ext = osc_extent_search(obj, index);
404         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
405                 return osc_extent_get(ext);
406         return NULL;
407 }
408
409 /* caller must have held object lock. */
410 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
411 {
412         struct rb_node   **n      = &obj->oo_root.rb_node;
413         struct rb_node    *parent = NULL;
414         struct osc_extent *tmp;
415
416         LASSERT(ext->oe_intree == 0);
417         LASSERT(ext->oe_obj == obj);
418         LASSERT(osc_object_is_locked(obj));
419         while (*n != NULL) {
420                 tmp = rb_extent(*n);
421                 parent = *n;
422
423                 if (ext->oe_end < tmp->oe_start)
424                         n = &(*n)->rb_left;
425                 else if (ext->oe_start > tmp->oe_end)
426                         n = &(*n)->rb_right;
427                 else
428                         EASSERTF(0, tmp, EXTSTR, EXTPARA(ext));
429         }
430         rb_link_node(&ext->oe_node, parent, n);
431         rb_insert_color(&ext->oe_node, &obj->oo_root);
432         osc_extent_get(ext);
433         ext->oe_intree = 1;
434 }
435
436 /* caller must have held object lock. */
437 static void osc_extent_erase(struct osc_extent *ext)
438 {
439         struct osc_object *obj = ext->oe_obj;
440         LASSERT(osc_object_is_locked(obj));
441         if (ext->oe_intree) {
442                 rb_erase(&ext->oe_node, &obj->oo_root);
443                 ext->oe_intree = 0;
444                 /* rbtree held a refcount */
445                 osc_extent_put_trust(ext);
446         }
447 }
448
449 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
450 {
451         struct osc_object *obj = ext->oe_obj;
452
453         LASSERT(osc_object_is_locked(obj));
454         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
455         if (ext->oe_state == OES_CACHE) {
456                 osc_extent_state_set(ext, OES_ACTIVE);
457                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
458         }
459         cfs_atomic_inc(&ext->oe_users);
460         cfs_list_del_init(&ext->oe_link);
461         return osc_extent_get(ext);
462 }
463
464 static void __osc_extent_remove(struct osc_extent *ext)
465 {
466         LASSERT(osc_object_is_locked(ext->oe_obj));
467         LASSERT(cfs_list_empty(&ext->oe_pages));
468         osc_extent_erase(ext);
469         cfs_list_del_init(&ext->oe_link);
470         osc_extent_state_set(ext, OES_INV);
471         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
472 }
473
474 static void osc_extent_remove(struct osc_extent *ext)
475 {
476         struct osc_object *obj = ext->oe_obj;
477
478         osc_object_lock(obj);
479         __osc_extent_remove(ext);
480         osc_object_unlock(obj);
481 }
482
483 /**
484  * This function is used to merge extents to get better performance. It checks
485  * if @cur and @victim are contiguous at chunk level.
486  */
487 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
488                             struct osc_extent *victim)
489 {
490         struct osc_object *obj = cur->oe_obj;
491         pgoff_t chunk_start;
492         pgoff_t chunk_end;
493         int ppc_bits;
494
495         LASSERT(cur->oe_state == OES_CACHE);
496         LASSERT(osc_object_is_locked(obj));
497         if (victim == NULL)
498                 return -EINVAL;
499
500         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
501                 return -EBUSY;
502
503         if (cur->oe_max_end != victim->oe_max_end)
504                 return -ERANGE;
505
506         LASSERT(cur->oe_osclock == victim->oe_osclock);
507         ppc_bits = osc_cli(obj)->cl_chunkbits - CFS_PAGE_SHIFT;
508         chunk_start = cur->oe_start >> ppc_bits;
509         chunk_end   = cur->oe_end   >> ppc_bits;
510         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
511             chunk_end + 1 != victim->oe_start >> ppc_bits)
512                 return -ERANGE;
513
514         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
515
516         cur->oe_start     = min(cur->oe_start, victim->oe_start);
517         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
518         cur->oe_grants   += victim->oe_grants;
519         cur->oe_nr_pages += victim->oe_nr_pages;
520         /* only the following bits are needed to merge */
521         cur->oe_urgent   |= victim->oe_urgent;
522         cur->oe_memalloc |= victim->oe_memalloc;
523         cfs_list_splice_init(&victim->oe_pages, &cur->oe_pages);
524         cfs_list_del_init(&victim->oe_link);
525         victim->oe_nr_pages = 0;
526
527         osc_extent_get(victim);
528         __osc_extent_remove(victim);
529         osc_extent_put(env, victim);
530
531         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
532         return 0;
533 }
534
535 /**
536  * Drop user count of osc_extent, and unplug IO asynchronously.
537  */
538 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
539 {
540         struct osc_object *obj = ext->oe_obj;
541         int rc = 0;
542         ENTRY;
543
544         LASSERT(cfs_atomic_read(&ext->oe_users) > 0);
545         LASSERT(sanity_check(ext) == 0);
546         LASSERT(ext->oe_grants > 0);
547
548         if (cfs_atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
549                 LASSERT(ext->oe_state == OES_ACTIVE);
550                 if (ext->oe_trunc_pending) {
551                         /* a truncate process is waiting for this extent.
552                          * This may happen due to a race, check
553                          * osc_cache_truncate_start(). */
554                         osc_extent_state_set(ext, OES_TRUNC);
555                         ext->oe_trunc_pending = 0;
556                 } else {
557                         osc_extent_state_set(ext, OES_CACHE);
558                         osc_update_pending(obj, OBD_BRW_WRITE,
559                                            ext->oe_nr_pages);
560
561                         /* try to merge the previous and next extent. */
562                         osc_extent_merge(env, ext, prev_extent(ext));
563                         osc_extent_merge(env, ext, next_extent(ext));
564
565                         if (ext->oe_urgent)
566                                 cfs_list_move_tail(&ext->oe_link,
567                                                    &obj->oo_urgent_exts);
568                 }
569                 osc_object_unlock(obj);
570
571                 osc_io_unplug_async(env, osc_cli(obj), obj);
572         }
573         osc_extent_put(env, ext);
574         RETURN(rc);
575 }
576
577 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
578 {
579         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
580 }
581
582 /**
583  * Find or create an extent which includes @index, core function to manage
584  * extent tree.
585  */
586 struct osc_extent *osc_extent_find(const struct lu_env *env,
587                                    struct osc_object *obj, pgoff_t index,
588                                    int *grants)
589
590 {
591         struct client_obd *cli = osc_cli(obj);
592         struct cl_lock    *lock;
593         struct osc_extent *cur;
594         struct osc_extent *ext;
595         struct osc_extent *conflict = NULL;
596         struct osc_extent *found = NULL;
597         pgoff_t    chunk;
598         pgoff_t    max_end;
599         int        max_pages; /* max_pages_per_rpc */
600         int        chunksize;
601         int        ppc_bits; /* pages per chunk bits */
602         int        chunk_mask;
603         int        rc;
604         ENTRY;
605
606         cur = osc_extent_alloc(obj);
607         if (cur == NULL)
608                 RETURN(ERR_PTR(-ENOMEM));
609
610         lock = cl_lock_at_pgoff(env, osc2cl(obj), index, NULL, 1, 0);
611         LASSERT(lock != NULL);
612         LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
613
614         LASSERT(cli->cl_chunkbits >= CFS_PAGE_SHIFT);
615         ppc_bits   = cli->cl_chunkbits - CFS_PAGE_SHIFT;
616         chunk_mask = ~((1 << ppc_bits) - 1);
617         chunksize  = 1 << cli->cl_chunkbits;
618         chunk      = index >> ppc_bits;
619
620         /* align end to rpc edge, rpc size may not be a power 2 integer. */
621         max_pages = cli->cl_max_pages_per_rpc;
622         LASSERT((max_pages & ~chunk_mask) == 0);
623         max_end = index - (index % max_pages) + max_pages - 1;
624         max_end = min_t(pgoff_t, max_end, lock->cll_descr.cld_end);
625
626         /* initialize new extent by parameters so far */
627         cur->oe_max_end = max_end;
628         cur->oe_start   = index & chunk_mask;
629         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
630         if (cur->oe_start < lock->cll_descr.cld_start)
631                 cur->oe_start = lock->cll_descr.cld_start;
632         if (cur->oe_end > max_end)
633                 cur->oe_end = max_end;
634         cur->oe_osclock = lock;
635         cur->oe_grants  = 0;
636         cur->oe_mppr    = max_pages;
637
638         /* grants has been allocated by caller */
639         LASSERTF(*grants >= chunksize + cli->cl_extent_tax,
640                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_extent_tax);
641         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR, EXTPARA(cur));
642
643 restart:
644         osc_object_lock(obj);
645         ext = osc_extent_search(obj, cur->oe_start);
646         if (ext == NULL)
647                 ext = first_extent(obj);
648         while (ext != NULL) {
649                 loff_t ext_chk_start = ext->oe_start >> ppc_bits;
650                 loff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
651
652                 LASSERT(sanity_check_nolock(ext) == 0);
653                 if (chunk > ext_chk_end + 1)
654                         break;
655
656                 /* if covering by different locks, no chance to match */
657                 if (lock != ext->oe_osclock) {
658                         EASSERTF(!overlapped(ext, cur), ext,
659                                  EXTSTR, EXTPARA(cur));
660
661                         ext = next_extent(ext);
662                         continue;
663                 }
664
665                 /* discontiguous chunks? */
666                 if (chunk + 1 < ext_chk_start) {
667                         ext = next_extent(ext);
668                         continue;
669                 }
670
671                 /* ok, from now on, ext and cur have these attrs:
672                  * 1. covered by the same lock
673                  * 2. contiguous at chunk level or overlapping. */
674
675                 if (overlapped(ext, cur)) {
676                         /* cur is the minimum unit, so overlapping means
677                          * full contain. */
678                         EASSERTF((ext->oe_start <= cur->oe_start &&
679                                   ext->oe_end >= cur->oe_end),
680                                  ext, EXTSTR, EXTPARA(cur));
681
682                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
683                                 /* for simplicity, we wait for this extent to
684                                  * finish before going forward. */
685                                 conflict = osc_extent_get(ext);
686                                 break;
687                         }
688
689                         found = osc_extent_hold(ext);
690                         break;
691                 }
692
693                 /* non-overlapped extent */
694                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
695                         /* we can't do anything for a non OES_CACHE extent, or
696                          * if there is someone waiting for this extent to be
697                          * flushed, try next one. */
698                         ext = next_extent(ext);
699                         continue;
700                 }
701
702                 /* check if they belong to the same rpc slot before trying to
703                  * merge. the extents are not overlapped and contiguous at
704                  * chunk level to get here. */
705                 if (ext->oe_max_end != max_end) {
706                         /* if they don't belong to the same RPC slot or
707                          * max_pages_per_rpc has ever changed, do not merge. */
708                         ext = next_extent(ext);
709                         continue;
710                 }
711
712                 /* it's required that an extent must be contiguous at chunk
713                  * level so that we know the whole extent is covered by grant
714                  * (the pages in the extent are NOT required to be contiguous).
715                  * Otherwise, it will be too much difficult to know which
716                  * chunks have grants allocated. */
717
718                 /* try to do front merge - extend ext's start */
719                 if (chunk + 1 == ext_chk_start) {
720                         /* ext must be chunk size aligned */
721                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
722
723                         /* pull ext's start back to cover cur */
724                         ext->oe_start   = cur->oe_start;
725                         ext->oe_grants += chunksize;
726                         *grants -= chunksize;
727
728                         found = osc_extent_hold(ext);
729                 } else if (chunk == ext_chk_end + 1) {
730                         /* rear merge */
731                         ext->oe_end     = cur->oe_end;
732                         ext->oe_grants += chunksize;
733                         *grants -= chunksize;
734
735                         /* try to merge with the next one because we just fill
736                          * in a gap */
737                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
738                                 /* we can save extent tax from next extent */
739                                 *grants += cli->cl_extent_tax;
740
741                         found = osc_extent_hold(ext);
742                 }
743                 if (found != NULL)
744                         break;
745
746                 ext = next_extent(ext);
747         }
748
749         osc_extent_tree_dump(D_CACHE, obj);
750         if (found != NULL) {
751                 LASSERT(conflict == NULL);
752                 if (!IS_ERR(found)) {
753                         LASSERT(found->oe_osclock == cur->oe_osclock);
754                         OSC_EXTENT_DUMP(D_CACHE, found,
755                                         "found caching ext for %lu.\n", index);
756                 }
757         } else if (conflict == NULL) {
758                 /* create a new extent */
759                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
760                 cur->oe_grants = chunksize + cli->cl_extent_tax;
761                 *grants -= cur->oe_grants;
762                 LASSERT(*grants >= 0);
763
764                 cur->oe_state = OES_CACHE;
765                 found = osc_extent_hold(cur);
766                 osc_extent_insert(obj, cur);
767                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
768                                 index, lock->cll_descr.cld_end);
769         }
770         osc_object_unlock(obj);
771
772         if (conflict != NULL) {
773                 LASSERT(found == NULL);
774
775                 /* waiting for IO to finish. Please notice that it's impossible
776                  * to be an OES_TRUNC extent. */
777                 rc = osc_extent_wait(env, conflict, OES_INV);
778                 osc_extent_put(env, conflict);
779                 conflict = NULL;
780                 if (rc < 0)
781                         GOTO(out, found = ERR_PTR(rc));
782
783                 goto restart;
784         }
785         EXIT;
786
787 out:
788         osc_extent_put(env, cur);
789         LASSERT(*grants >= 0);
790         return found;
791 }
792
793 /**
794  * Called when IO is finished to an extent.
795  */
796 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
797                       int sent, int rc)
798 {
799         struct client_obd *cli = osc_cli(ext->oe_obj);
800         struct osc_async_page *oap;
801         struct osc_async_page *tmp;
802         int nr_pages = ext->oe_nr_pages;
803         int lost_grant = 0;
804         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
805         __u64 last_off = 0;
806         int last_count = -1;
807         ENTRY;
808
809         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
810
811         ext->oe_rc = rc ?: ext->oe_nr_pages;
812         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
813         cfs_list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
814                                      oap_pending_item) {
815                 cfs_list_del_init(&oap->oap_rpc_item);
816                 cfs_list_del_init(&oap->oap_pending_item);
817                 if (last_off <= oap->oap_obj_off) {
818                         last_off = oap->oap_obj_off;
819                         last_count = oap->oap_count;
820                 }
821
822                 --ext->oe_nr_pages;
823                 osc_ap_completion(env, cli, oap, sent, rc);
824         }
825         EASSERT(ext->oe_nr_pages == 0, ext);
826
827         if (!sent) {
828                 lost_grant = ext->oe_grants;
829         } else if (blocksize < CFS_PAGE_SIZE &&
830                    last_count != CFS_PAGE_SIZE) {
831                 /* For short writes we shouldn't count parts of pages that
832                  * span a whole chunk on the OST side, or our accounting goes
833                  * wrong.  Should match the code in filter_grant_check. */
834                 int offset = oap->oap_page_off & ~CFS_PAGE_MASK;
835                 int count = oap->oap_count + (offset & (blocksize - 1));
836                 int end = (offset + oap->oap_count) & (blocksize - 1);
837                 if (end)
838                         count += blocksize - end;
839
840                 lost_grant = CFS_PAGE_SIZE - count;
841         }
842         if (ext->oe_grants > 0)
843                 osc_free_grant(cli, nr_pages, lost_grant);
844
845         osc_extent_remove(ext);
846         /* put the refcount for RPC */
847         osc_extent_put(env, ext);
848         RETURN(0);
849 }
850
851 static int extent_wait_cb(struct osc_extent *ext, int state)
852 {
853         int ret;
854
855         osc_object_lock(ext->oe_obj);
856         ret = ext->oe_state == state;
857         osc_object_unlock(ext->oe_obj);
858
859         return ret;
860 }
861
862 /**
863  * Wait for the extent's state to become @state.
864  */
865 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
866                            int state)
867 {
868         struct osc_object *obj = ext->oe_obj;
869         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
870                                                   LWI_ON_SIGNAL_NOOP, NULL);
871         int rc = 0;
872         ENTRY;
873
874         osc_object_lock(obj);
875         LASSERT(sanity_check_nolock(ext) == 0);
876         /* `Kick' this extent only if the caller is waiting for it to be
877          * written out. */
878         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
879                 if (ext->oe_state == OES_ACTIVE) {
880                         ext->oe_urgent = 1;
881                 } else if (ext->oe_state == OES_CACHE) {
882                         ext->oe_urgent = 1;
883                         osc_extent_hold(ext);
884                         rc = 1;
885                 }
886         }
887         osc_object_unlock(obj);
888         if (rc == 1)
889                 osc_extent_release(env, ext);
890
891         /* wait for the extent until its state becomes @state */
892         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
893         if (rc == -ETIMEDOUT) {
894                 OSC_EXTENT_DUMP(D_ERROR, ext,
895                         "%s: wait ext to %d timedout, recovery in progress?\n",
896                         osc_export(obj)->exp_obd->obd_name, state);
897
898                 lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
899                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
900                                   &lwi);
901         }
902         if (rc == 0 && ext->oe_rc < 0)
903                 rc = ext->oe_rc;
904         RETURN(rc);
905 }
906
907 /**
908  * Discard pages with index greater than @size. If @ext is overlapped with
909  * @size, then partial truncate happens.
910  */
911 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
912                                 bool partial)
913 {
914         struct cl_env_nest     nest;
915         struct lu_env         *env;
916         struct cl_io          *io;
917         struct osc_object     *obj = ext->oe_obj;
918         struct client_obd     *cli = osc_cli(obj);
919         struct osc_async_page *oap;
920         struct osc_async_page *tmp;
921         int                    pages_in_chunk = 0;
922         int                    ppc_bits    = cli->cl_chunkbits - CFS_PAGE_SHIFT;
923         __u64                  trunc_chunk = trunc_index >> ppc_bits;
924         int                    grants   = 0;
925         int                    nr_pages = 0;
926         int                    rc       = 0;
927         ENTRY;
928
929         LASSERT(sanity_check(ext) == 0);
930         LASSERT(ext->oe_state == OES_TRUNC);
931         LASSERT(!ext->oe_urgent);
932
933         /* Request new lu_env.
934          * We can't use that env from osc_cache_truncate_start() because
935          * it's from lov_io_sub and not fully initialized. */
936         env = cl_env_nested_get(&nest);
937         io  = &osc_env_info(env)->oti_io;
938         io->ci_obj = cl_object_top(osc2cl(obj));
939         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
940         if (rc < 0)
941                 GOTO(out, rc);
942
943         /* discard all pages with index greater then trunc_index */
944         cfs_list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
945                                      oap_pending_item) {
946                 struct cl_page  *sub  = oap2cl_page(oap);
947                 struct cl_page  *page = cl_page_top(sub);
948
949                 LASSERT(cfs_list_empty(&oap->oap_rpc_item));
950
951                 /* only discard the pages with their index greater than
952                  * trunc_index, and ... */
953                 if (sub->cp_index < trunc_index ||
954                     (sub->cp_index == trunc_index && partial)) {
955                         /* accounting how many pages remaining in the chunk
956                          * so that we can calculate grants correctly. */
957                         if (sub->cp_index >> ppc_bits == trunc_chunk)
958                                 ++pages_in_chunk;
959                         continue;
960                 }
961
962                 cfs_list_del_init(&oap->oap_pending_item);
963
964                 cl_page_get(page);
965                 lu_ref_add(&page->cp_reference, "truncate", cfs_current());
966
967                 if (cl_page_own(env, io, page) == 0) {
968                         cl_page_unmap(env, io, page);
969                         cl_page_discard(env, io, page);
970                         cl_page_disown(env, io, page);
971                 } else {
972                         LASSERT(page->cp_state == CPS_FREEING);
973                         LASSERT(0);
974                 }
975
976                 lu_ref_del(&page->cp_reference, "truncate", cfs_current());
977                 cl_page_put(env, page);
978
979                 --ext->oe_nr_pages;
980                 ++nr_pages;
981         }
982         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
983                       ext->oe_nr_pages == 0),
984                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
985
986         osc_object_lock(obj);
987         if (ext->oe_nr_pages == 0) {
988                 LASSERT(pages_in_chunk == 0);
989                 grants = ext->oe_grants;
990                 ext->oe_grants = 0;
991         } else { /* calculate how many grants we can free */
992                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
993                 pgoff_t last_index;
994
995
996                 /* if there is no pages in this chunk, we can also free grants
997                  * for the last chunk */
998                 if (pages_in_chunk == 0) {
999                         /* if this is the 1st chunk and no pages in this chunk,
1000                          * ext->oe_nr_pages must be zero, so we should be in
1001                          * the other if-clause. */
1002                         LASSERT(trunc_chunk > 0);
1003                         --trunc_chunk;
1004                         ++chunks;
1005                 }
1006
1007                 /* this is what we can free from this extent */
1008                 grants          = chunks << cli->cl_chunkbits;
1009                 ext->oe_grants -= grants;
1010                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1011                 ext->oe_end     = min(last_index, ext->oe_max_end);
1012                 LASSERT(ext->oe_end >= ext->oe_start);
1013                 LASSERT(ext->oe_grants > 0);
1014         }
1015         osc_object_unlock(obj);
1016
1017         if (grants > 0 || nr_pages > 0)
1018                 osc_free_grant(cli, nr_pages, grants);
1019
1020 out:
1021         cl_io_fini(env, io);
1022         cl_env_nested_put(&nest, env);
1023         RETURN(rc);
1024 }
1025
1026 /**
1027  * This function is used to make the extent prepared for transfer.
1028  * A race with flusing page - ll_writepage() has to be handled cautiously.
1029  */
1030 static int osc_extent_make_ready(const struct lu_env *env,
1031                                  struct osc_extent *ext)
1032 {
1033         struct osc_async_page *oap;
1034         struct osc_async_page *last = NULL;
1035         struct osc_object *obj = ext->oe_obj;
1036         int page_count = 0;
1037         int rc;
1038         ENTRY;
1039
1040         /* we're going to grab page lock, so object lock must not be taken. */
1041         LASSERT(sanity_check(ext) == 0);
1042         /* in locking state, any process should not touch this extent. */
1043         EASSERT(ext->oe_state == OES_LOCKING, ext);
1044         EASSERT(ext->oe_owner != NULL, ext);
1045
1046         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1047
1048         cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1049                 ++page_count;
1050                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1051                         last = oap;
1052
1053                 /* checking ASYNC_READY is race safe */
1054                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1055                         continue;
1056
1057                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1058                 switch (rc) {
1059                 case 0:
1060                         spin_lock(&oap->oap_lock);
1061                         oap->oap_async_flags |= ASYNC_READY;
1062                         spin_unlock(&oap->oap_lock);
1063                         break;
1064                 case -EALREADY:
1065                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1066                         break;
1067                 default:
1068                         LASSERTF(0, "unknown return code: %d\n", rc);
1069                 }
1070         }
1071
1072         LASSERT(page_count == ext->oe_nr_pages);
1073         LASSERT(last != NULL);
1074         /* the last page is the only one we need to refresh its count by
1075          * the size of file. */
1076         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1077                 last->oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1078                 LASSERT(last->oap_count > 0);
1079                 LASSERT(last->oap_page_off + last->oap_count <= CFS_PAGE_SIZE);
1080                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1081         }
1082
1083         /* for the rest of pages, we don't need to call osf_refresh_count()
1084          * because it's known they are not the last page */
1085         cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1086                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1087                         oap->oap_count = CFS_PAGE_SIZE - oap->oap_page_off;
1088                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1089                 }
1090         }
1091
1092         osc_object_lock(obj);
1093         osc_extent_state_set(ext, OES_RPC);
1094         osc_object_unlock(obj);
1095         /* get a refcount for RPC. */
1096         osc_extent_get(ext);
1097
1098         RETURN(0);
1099 }
1100
1101 /**
1102  * Quick and simple version of osc_extent_find(). This function is frequently
1103  * called to expand the extent for the same IO. To expand the extent, the
1104  * page index must be in the same or next chunk of ext->oe_end.
1105  */
1106 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
1107 {
1108         struct osc_object *obj = ext->oe_obj;
1109         struct client_obd *cli = osc_cli(obj);
1110         struct osc_extent *next;
1111         int ppc_bits = cli->cl_chunkbits - CFS_PAGE_SHIFT;
1112         pgoff_t chunk = index >> ppc_bits;
1113         pgoff_t end_chunk;
1114         pgoff_t end_index;
1115         int chunksize = 1 << cli->cl_chunkbits;
1116         int rc = 0;
1117         ENTRY;
1118
1119         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1120         osc_object_lock(obj);
1121         LASSERT(sanity_check_nolock(ext) == 0);
1122         end_chunk = ext->oe_end >> ppc_bits;
1123         if (chunk > end_chunk + 1)
1124                 GOTO(out, rc = -ERANGE);
1125
1126         if (end_chunk >= chunk)
1127                 GOTO(out, rc = 0);
1128
1129         LASSERT(end_chunk + 1 == chunk);
1130         /* try to expand this extent to cover @index */
1131         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1132
1133         next = next_extent(ext);
1134         if (next != NULL && next->oe_start <= end_index)
1135                 /* complex mode - overlapped with the next extent,
1136                  * this case will be handled by osc_extent_find() */
1137                 GOTO(out, rc = -EAGAIN);
1138
1139         ext->oe_end = end_index;
1140         ext->oe_grants += chunksize;
1141         *grants -= chunksize;
1142         LASSERT(*grants >= 0);
1143         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1144                  "overlapped after expanding for %lu.\n", index);
1145         EXIT;
1146
1147 out:
1148         osc_object_unlock(obj);
1149         RETURN(rc);
1150 }
1151
1152 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1153                                   const char *func, int line)
1154 {
1155         struct osc_extent *ext;
1156         int cnt;
1157
1158         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1159                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1160
1161         /* osc_object_lock(obj); */
1162         cnt = 1;
1163         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1164                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1165
1166         cnt = 1;
1167         cfs_list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1168                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1169
1170         cnt = 1;
1171         cfs_list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1172                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1173
1174         cnt = 1;
1175         cfs_list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1176                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1177         /* osc_object_unlock(obj); */
1178 }
1179
1180 /* ------------------ osc extent end ------------------ */
1181
1182 static inline int osc_is_ready(struct osc_object *osc)
1183 {
1184         return !cfs_list_empty(&osc->oo_ready_item) ||
1185                !cfs_list_empty(&osc->oo_hp_ready_item);
1186 }
1187
1188 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1189         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1190                (OSC), osc_is_ready(OSC),                                       \
1191                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1192                list_empty_marker(&(OSC)->oo_ready_item),                       \
1193                cfs_atomic_read(&(OSC)->oo_nr_writes),                          \
1194                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1195                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1196                cfs_atomic_read(&(OSC)->oo_nr_reads),                           \
1197                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1198                ##args)
1199
1200 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1201                           int cmd)
1202 {
1203         struct osc_page *opg  = oap2osc_page(oap);
1204         struct cl_page  *page = cl_page_top(oap2cl_page(oap));
1205         int result;
1206
1207         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1208
1209         ENTRY;
1210         result = cl_page_make_ready(env, page, CRT_WRITE);
1211         if (result == 0)
1212                 opg->ops_submit_time = cfs_time_current();
1213         RETURN(result);
1214 }
1215
1216 static int osc_refresh_count(const struct lu_env *env,
1217                              struct osc_async_page *oap, int cmd)
1218 {
1219         struct osc_page  *opg = oap2osc_page(oap);
1220         struct cl_page   *page = oap2cl_page(oap);
1221         struct cl_object *obj;
1222         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1223
1224         int result;
1225         loff_t kms;
1226
1227         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1228         LASSERT(!(cmd & OBD_BRW_READ));
1229         LASSERT(opg != NULL);
1230         obj = opg->ops_cl.cpl_obj;
1231
1232         cl_object_attr_lock(obj);
1233         result = cl_object_attr_get(env, obj, attr);
1234         cl_object_attr_unlock(obj);
1235         if (result < 0)
1236                 return result;
1237         kms = attr->cat_kms;
1238         if (cl_offset(obj, page->cp_index) >= kms)
1239                 /* catch race with truncate */
1240                 return 0;
1241         else if (cl_offset(obj, page->cp_index + 1) > kms)
1242                 /* catch sub-page write at end of file */
1243                 return kms % CFS_PAGE_SIZE;
1244         else
1245                 return CFS_PAGE_SIZE;
1246 }
1247
1248 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1249                           int cmd, int rc)
1250 {
1251         struct osc_page   *opg  = oap2osc_page(oap);
1252         struct cl_page    *page = cl_page_top(oap2cl_page(oap));
1253         struct osc_object *obj  = cl2osc(opg->ops_cl.cpl_obj);
1254         enum cl_req_type   crt;
1255         int srvlock;
1256
1257         ENTRY;
1258
1259         cmd &= ~OBD_BRW_NOQUOTA;
1260         LASSERT(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ));
1261         LASSERT(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE));
1262         LASSERT(opg->ops_transfer_pinned);
1263
1264         /*
1265          * page->cp_req can be NULL if io submission failed before
1266          * cl_req was allocated.
1267          */
1268         if (page->cp_req != NULL)
1269                 cl_req_page_done(env, page);
1270         LASSERT(page->cp_req == NULL);
1271
1272         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1273         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1274         opg->ops_transfer_pinned = 0;
1275
1276         spin_lock(&obj->oo_seatbelt);
1277         LASSERT(opg->ops_submitter != NULL);
1278         LASSERT(!cfs_list_empty(&opg->ops_inflight));
1279         cfs_list_del_init(&opg->ops_inflight);
1280         opg->ops_submitter = NULL;
1281         spin_unlock(&obj->oo_seatbelt);
1282
1283         opg->ops_submit_time = 0;
1284         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1285
1286         cl_page_completion(env, page, crt, rc);
1287
1288         /* statistic */
1289         if (rc == 0 && srvlock) {
1290                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1291                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1292                 int bytes = oap->oap_count;
1293
1294                 if (crt == CRT_READ)
1295                         stats->os_lockless_reads += bytes;
1296                 else
1297                         stats->os_lockless_writes += bytes;
1298         }
1299
1300         /*
1301          * This has to be the last operation with the page, as locks are
1302          * released in cl_page_completion() and nothing except for the
1303          * reference counter protects page from concurrent reclaim.
1304          */
1305         lu_ref_del(&page->cp_reference, "transfer", page);
1306         /*
1307          * As page->cp_obj is pinned by a reference from page->cp_req, it is
1308          * safe to call cl_page_put() without risking object destruction in a
1309          * non-blocking context.
1310          */
1311         cl_page_put(env, page);
1312         RETURN(0);
1313 }
1314
1315 #define OSC_DUMP_GRANT(cli, fmt, args...) do {                                \
1316         struct client_obd *__tmp = (cli);                                     \
1317         CDEBUG(D_CACHE, "%s: { dirty: %ld/%ld dirty_pages: %d/%d "            \
1318                "dropped: %ld avail: %ld, reserved: %ld, flight: %d } " fmt,   \
1319                __tmp->cl_import->imp_obd->obd_name,                           \
1320                __tmp->cl_dirty, __tmp->cl_dirty_max,                          \
1321                cfs_atomic_read(&obd_dirty_pages), obd_max_dirty_pages,        \
1322                __tmp->cl_lost_grant, __tmp->cl_avail_grant,                   \
1323                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight, ##args);      \
1324 } while (0)
1325
1326 /* caller must hold loi_list_lock */
1327 static void osc_consume_write_grant(struct client_obd *cli,
1328                                     struct brw_page *pga)
1329 {
1330         LASSERT_SPIN_LOCKED(&cli->cl_loi_list_lock.lock);
1331         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1332         cfs_atomic_inc(&obd_dirty_pages);
1333         cli->cl_dirty += CFS_PAGE_SIZE;
1334         pga->flag |= OBD_BRW_FROM_GRANT;
1335         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1336                CFS_PAGE_SIZE, pga, pga->pg);
1337         osc_update_next_shrink(cli);
1338 }
1339
1340 /* the companion to osc_consume_write_grant, called when a brw has completed.
1341  * must be called with the loi lock held. */
1342 static void osc_release_write_grant(struct client_obd *cli,
1343                                     struct brw_page *pga)
1344 {
1345         ENTRY;
1346
1347         LASSERT_SPIN_LOCKED(&cli->cl_loi_list_lock.lock);
1348         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1349                 EXIT;
1350                 return;
1351         }
1352
1353         pga->flag &= ~OBD_BRW_FROM_GRANT;
1354         cfs_atomic_dec(&obd_dirty_pages);
1355         cli->cl_dirty -= CFS_PAGE_SIZE;
1356         if (pga->flag & OBD_BRW_NOCACHE) {
1357                 pga->flag &= ~OBD_BRW_NOCACHE;
1358                 cfs_atomic_dec(&obd_dirty_transit_pages);
1359                 cli->cl_dirty_transit -= CFS_PAGE_SIZE;
1360         }
1361         EXIT;
1362 }
1363
1364 /**
1365  * To avoid sleeping with object lock held, it's good for us allocate enough
1366  * grants before entering into critical section.
1367  *
1368  * client_obd_list_lock held by caller
1369  */
1370 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1371 {
1372         int rc = -EDQUOT;
1373
1374         if (cli->cl_avail_grant >= bytes) {
1375                 cli->cl_avail_grant    -= bytes;
1376                 cli->cl_reserved_grant += bytes;
1377                 rc = 0;
1378         }
1379         return rc;
1380 }
1381
1382 static void __osc_unreserve_grant(struct client_obd *cli,
1383                                   unsigned int reserved, unsigned int unused)
1384 {
1385         /* it's quite normal for us to get more grant than reserved.
1386          * Thinking about a case that two extents merged by adding a new
1387          * chunk, we can save one extent tax. If extent tax is greater than
1388          * one chunk, we can save more grant by adding a new chunk */
1389         cli->cl_reserved_grant -= reserved;
1390         if (unused > reserved) {
1391                 cli->cl_avail_grant += reserved;
1392                 cli->cl_lost_grant  += unused - reserved;
1393         } else {
1394                 cli->cl_avail_grant += unused;
1395         }
1396 }
1397
1398 void osc_unreserve_grant(struct client_obd *cli,
1399                          unsigned int reserved, unsigned int unused)
1400 {
1401         client_obd_list_lock(&cli->cl_loi_list_lock);
1402         __osc_unreserve_grant(cli, reserved, unused);
1403         if (unused > 0)
1404                 osc_wake_cache_waiters(cli);
1405         client_obd_list_unlock(&cli->cl_loi_list_lock);
1406 }
1407
1408 /**
1409  * Free grant after IO is finished or canceled.
1410  *
1411  * @lost_grant is used to remember how many grants we have allocated but not
1412  * used, we should return these grants to OST. There're two cases where grants
1413  * can be lost:
1414  * 1. truncate;
1415  * 2. blocksize at OST is less than CFS_PAGE_SIZE and a partial page was
1416  *    written. In this case OST may use less chunks to serve this partial
1417  *    write. OSTs don't actually know the page size on the client side. so
1418  *    clients have to calculate lost grant by the blocksize on the OST.
1419  *    See filter_grant_check() for details.
1420  */
1421 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1422                            unsigned int lost_grant)
1423 {
1424         int grant = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
1425
1426         client_obd_list_lock(&cli->cl_loi_list_lock);
1427         cfs_atomic_sub(nr_pages, &obd_dirty_pages);
1428         cli->cl_dirty -= nr_pages << CFS_PAGE_SHIFT;
1429         cli->cl_lost_grant += lost_grant;
1430         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1431                 /* borrow some grant from truncate to avoid the case that
1432                  * truncate uses up all avail grant */
1433                 cli->cl_lost_grant -= grant;
1434                 cli->cl_avail_grant += grant;
1435         }
1436         osc_wake_cache_waiters(cli);
1437         client_obd_list_unlock(&cli->cl_loi_list_lock);
1438         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu\n",
1439                lost_grant, cli->cl_lost_grant,
1440                cli->cl_avail_grant, cli->cl_dirty);
1441 }
1442
1443 /**
1444  * The companion to osc_enter_cache(), called when @oap is no longer part of
1445  * the dirty accounting due to error.
1446  */
1447 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1448 {
1449         client_obd_list_lock(&cli->cl_loi_list_lock);
1450         osc_release_write_grant(cli, &oap->oap_brw_page);
1451         client_obd_list_unlock(&cli->cl_loi_list_lock);
1452 }
1453
1454 /**
1455  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1456  * is available.
1457  */
1458 static int osc_enter_cache_try(struct client_obd *cli,
1459                                struct osc_async_page *oap,
1460                                int bytes, int transient)
1461 {
1462         int rc;
1463
1464         OSC_DUMP_GRANT(cli, "need:%d.\n", bytes);
1465
1466         rc = osc_reserve_grant(cli, bytes);
1467         if (rc < 0)
1468                 return 0;
1469
1470         if (cli->cl_dirty + CFS_PAGE_SIZE <= cli->cl_dirty_max &&
1471             cfs_atomic_read(&obd_dirty_pages) + 1 <= obd_max_dirty_pages) {
1472                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1473                 if (transient) {
1474                         cli->cl_dirty_transit += CFS_PAGE_SIZE;
1475                         cfs_atomic_inc(&obd_dirty_transit_pages);
1476                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1477                 }
1478                 rc = 1;
1479         } else {
1480                 __osc_unreserve_grant(cli, bytes, bytes);
1481                 rc = 0;
1482         }
1483         return rc;
1484 }
1485
1486 /**
1487  * The main entry to reserve dirty page accounting. Usually the grant reserved
1488  * in this function will be freed in bulk in osc_free_grant() unless it fails
1489  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1490  *
1491  * The process will be put into sleep if it's already run out of grant.
1492  */
1493 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1494                            struct osc_async_page *oap, int bytes)
1495 {
1496         struct osc_object *osc = oap->oap_obj;
1497         struct lov_oinfo  *loi = osc->oo_oinfo;
1498         struct osc_cache_waiter ocw;
1499         struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
1500         int rc = -EDQUOT;
1501         ENTRY;
1502
1503         OSC_DUMP_GRANT(cli, "need:%d.\n", bytes);
1504
1505         client_obd_list_lock(&cli->cl_loi_list_lock);
1506
1507         /* force the caller to try sync io.  this can jump the list
1508          * of queued writes and create a discontiguous rpc stream */
1509         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1510             cli->cl_dirty_max < CFS_PAGE_SIZE     ||
1511             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync)
1512                 GOTO(out, rc = -EDQUOT);
1513
1514         /* Hopefully normal case - cache space and write credits available */
1515         if (osc_enter_cache_try(cli, oap, bytes, 0))
1516                 GOTO(out, rc = 0);
1517
1518         /* We can get here for two reasons: too many dirty pages in cache, or
1519          * run out of grants. In both cases we should write dirty pages out.
1520          * Adding a cache waiter will trigger urgent write-out no matter what
1521          * RPC size will be.
1522          * The exiting condition is no avail grants and no dirty pages caching,
1523          * that really means there is no space on the OST. */
1524         cfs_waitq_init(&ocw.ocw_waitq);
1525         ocw.ocw_oap   = oap;
1526         ocw.ocw_grant = bytes;
1527         while (cli->cl_dirty > 0 || cli->cl_w_in_flight > 0) {
1528                 cfs_list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1529                 ocw.ocw_rc = 0;
1530                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1531
1532                 osc_io_unplug(env, cli, osc, PDL_POLICY_ROUND);
1533
1534                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1535                        cli->cl_import->imp_obd->obd_name, &ocw, oap);
1536
1537                 rc = l_wait_event(ocw.ocw_waitq,
1538                                   cfs_list_empty(&ocw.ocw_entry), &lwi);
1539
1540                 client_obd_list_lock(&cli->cl_loi_list_lock);
1541                 cfs_list_del_init(&ocw.ocw_entry);
1542                 if (rc < 0)
1543                         break;
1544
1545                 rc = ocw.ocw_rc;
1546                 if (rc != -EDQUOT)
1547                         break;
1548                 if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1549                         rc = 0;
1550                         break;
1551                 }
1552         }
1553         EXIT;
1554
1555 out:
1556         client_obd_list_unlock(&cli->cl_loi_list_lock);
1557         OSC_DUMP_GRANT(cli, "returned %d.\n", rc);
1558         RETURN(rc);
1559 }
1560
1561 /* caller must hold loi_list_lock */
1562 void osc_wake_cache_waiters(struct client_obd *cli)
1563 {
1564         cfs_list_t *l, *tmp;
1565         struct osc_cache_waiter *ocw;
1566
1567         ENTRY;
1568         cfs_list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1569                 /* if we can't dirty more, we must wait until some is written */
1570                 if ((cli->cl_dirty + CFS_PAGE_SIZE > cli->cl_dirty_max) ||
1571                     (cfs_atomic_read(&obd_dirty_pages) + 1 >
1572                      obd_max_dirty_pages)) {
1573                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1574                                "osc max %ld, sys max %d\n", cli->cl_dirty,
1575                                cli->cl_dirty_max, obd_max_dirty_pages);
1576                         return;
1577                 }
1578
1579                 /* if still dirty cache but no grant wait for pending RPCs that
1580                  * may yet return us some grant before doing sync writes */
1581                 if (cli->cl_w_in_flight && cli->cl_avail_grant < CFS_PAGE_SIZE) {
1582                         CDEBUG(D_CACHE, "%u BRW writes in flight, no grant\n",
1583                                cli->cl_w_in_flight);
1584                         return;
1585                 }
1586
1587                 ocw = cfs_list_entry(l, struct osc_cache_waiter, ocw_entry);
1588                 cfs_list_del_init(&ocw->ocw_entry);
1589
1590                 ocw->ocw_rc = 0;
1591                 if (!osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1592                         ocw->ocw_rc = -EDQUOT;
1593
1594                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1595                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1596
1597                 cfs_waitq_signal(&ocw->ocw_waitq);
1598         }
1599
1600         EXIT;
1601 }
1602
1603 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1604 {
1605         int hprpc = !!cfs_list_empty(&osc->oo_hp_exts);
1606         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1607 }
1608
1609 /* This maintains the lists of pending pages to read/write for a given object
1610  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1611  * to quickly find objects that are ready to send an RPC. */
1612 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1613                          int cmd)
1614 {
1615         int invalid_import = 0;
1616         ENTRY;
1617
1618         /* if we have an invalid import we want to drain the queued pages
1619          * by forcing them through rpcs that immediately fail and complete
1620          * the pages.  recovery relies on this to empty the queued pages
1621          * before canceling the locks and evicting down the llite pages */
1622         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1623                 invalid_import = 1;
1624
1625         if (cmd & OBD_BRW_WRITE) {
1626                 if (cfs_atomic_read(&osc->oo_nr_writes) == 0)
1627                         RETURN(0);
1628                 if (invalid_import) {
1629                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1630                         RETURN(1);
1631                 }
1632                 if (!cfs_list_empty(&osc->oo_hp_exts)) {
1633                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1634                         RETURN(1);
1635                 }
1636                 if (!cfs_list_empty(&osc->oo_urgent_exts)) {
1637                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1638                         RETURN(1);
1639                 }
1640                 /* trigger a write rpc stream as long as there are dirtiers
1641                  * waiting for space.  as they're waiting, they're not going to
1642                  * create more pages to coalesce with what's waiting.. */
1643                 if (!cfs_list_empty(&cli->cl_cache_waiters)) {
1644                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1645                         RETURN(1);
1646                 }
1647                 if (cfs_atomic_read(&osc->oo_nr_writes) >=
1648                     cli->cl_max_pages_per_rpc)
1649                         RETURN(1);
1650         } else {
1651                 if (cfs_atomic_read(&osc->oo_nr_reads) == 0)
1652                         RETURN(0);
1653                 if (invalid_import) {
1654                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1655                         RETURN(1);
1656                 }
1657                 /* all read are urgent. */
1658                 if (!cfs_list_empty(&osc->oo_reading_exts))
1659                         RETURN(1);
1660         }
1661
1662         RETURN(0);
1663 }
1664
1665 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1666 {
1667         struct client_obd *cli = osc_cli(obj);
1668         if (cmd & OBD_BRW_WRITE) {
1669                 cfs_atomic_add(delta, &obj->oo_nr_writes);
1670                 cfs_atomic_add(delta, &cli->cl_pending_w_pages);
1671                 LASSERT(cfs_atomic_read(&obj->oo_nr_writes) >= 0);
1672         } else {
1673                 cfs_atomic_add(delta, &obj->oo_nr_reads);
1674                 cfs_atomic_add(delta, &cli->cl_pending_r_pages);
1675                 LASSERT(cfs_atomic_read(&obj->oo_nr_reads) >= 0);
1676         }
1677         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1678 }
1679
1680 static int osc_makes_hprpc(struct osc_object *obj)
1681 {
1682         return !cfs_list_empty(&obj->oo_hp_exts);
1683 }
1684
1685 static void on_list(cfs_list_t *item, cfs_list_t *list, int should_be_on)
1686 {
1687         if (cfs_list_empty(item) && should_be_on)
1688                 cfs_list_add_tail(item, list);
1689         else if (!cfs_list_empty(item) && !should_be_on)
1690                 cfs_list_del_init(item);
1691 }
1692
1693 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1694  * can find pages to build into rpcs quickly */
1695 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1696 {
1697         if (osc_makes_hprpc(osc)) {
1698                 /* HP rpc */
1699                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1700                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1701         } else {
1702                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1703                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1704                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1705                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1706         }
1707
1708         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1709                 cfs_atomic_read(&osc->oo_nr_writes) > 0);
1710
1711         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1712                 cfs_atomic_read(&osc->oo_nr_reads) > 0);
1713
1714         return osc_is_ready(osc);
1715 }
1716
1717 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1718 {
1719         int is_ready;
1720
1721         client_obd_list_lock(&cli->cl_loi_list_lock);
1722         is_ready = __osc_list_maint(cli, osc);
1723         client_obd_list_unlock(&cli->cl_loi_list_lock);
1724
1725         return is_ready;
1726 }
1727
1728 /* this is trying to propogate async writeback errors back up to the
1729  * application.  As an async write fails we record the error code for later if
1730  * the app does an fsync.  As long as errors persist we force future rpcs to be
1731  * sync so that the app can get a sync error and break the cycle of queueing
1732  * pages for which writeback will fail. */
1733 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1734                            int rc)
1735 {
1736         if (rc) {
1737                 if (!ar->ar_rc)
1738                         ar->ar_rc = rc;
1739
1740                 ar->ar_force_sync = 1;
1741                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1742                 return;
1743
1744         }
1745
1746         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1747                 ar->ar_force_sync = 0;
1748 }
1749
1750 /* this must be called holding the loi list lock to give coverage to exit_cache,
1751  * async_flag maintenance, and oap_request */
1752 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1753                               struct osc_async_page *oap, int sent, int rc)
1754 {
1755         struct osc_object *osc = oap->oap_obj;
1756         struct lov_oinfo  *loi = osc->oo_oinfo;
1757         __u64 xid = 0;
1758
1759         ENTRY;
1760         if (oap->oap_request != NULL) {
1761                 xid = ptlrpc_req_xid(oap->oap_request);
1762                 ptlrpc_req_finished(oap->oap_request);
1763                 oap->oap_request = NULL;
1764         }
1765
1766         /* As the transfer for this page is being done, clear the flags */
1767         spin_lock(&oap->oap_lock);
1768         oap->oap_async_flags = 0;
1769         spin_unlock(&oap->oap_lock);
1770         oap->oap_interrupted = 0;
1771
1772         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1773                 client_obd_list_lock(&cli->cl_loi_list_lock);
1774                 osc_process_ar(&cli->cl_ar, xid, rc);
1775                 osc_process_ar(&loi->loi_ar, xid, rc);
1776                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1777         }
1778
1779         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1780         if (rc)
1781                 CERROR("completion on oap %p obj %p returns %d.\n",
1782                        oap, osc, rc);
1783
1784         EXIT;
1785 }
1786
1787 /**
1788  * Try to add extent to one RPC. We need to think about the following things:
1789  * - # of pages must not be over max_pages_per_rpc
1790  * - extent must be compatible with previous ones
1791  */
1792 static int try_to_add_extent_for_io(struct client_obd *cli,
1793                                     struct osc_extent *ext, cfs_list_t *rpclist,
1794                                     int *pc, unsigned int *max_pages)
1795 {
1796         struct osc_extent *tmp;
1797         ENTRY;
1798
1799         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1800                 ext);
1801
1802         *max_pages = max(ext->oe_mppr, *max_pages);
1803         if (*pc + ext->oe_nr_pages > *max_pages)
1804                 RETURN(0);
1805
1806         cfs_list_for_each_entry(tmp, rpclist, oe_link) {
1807                 EASSERT(tmp->oe_owner == cfs_current(), tmp);
1808 #if 0
1809                 if (overlapped(tmp, ext)) {
1810                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1811                         EASSERT(0, ext);
1812                 }
1813 #endif
1814
1815                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1816                     !tmp->oe_grants != !ext->oe_grants)
1817                         RETURN(0);
1818
1819                 /* remove break for strict check */
1820                 break;
1821         }
1822
1823         *pc += ext->oe_nr_pages;
1824         cfs_list_move_tail(&ext->oe_link, rpclist);
1825         ext->oe_owner = cfs_current();
1826         RETURN(1);
1827 }
1828
1829 /**
1830  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1831  * get_write_extent() takes all appropriate extents in atomic.
1832  *
1833  * The following policy is used to collect extents for IO:
1834  * 1. Add as many HP extents as possible;
1835  * 2. Add the first urgent extent in urgent extent list and take it out of
1836  *    urgent list;
1837  * 3. Add subsequent extents of this urgent extent;
1838  * 4. If urgent list is not empty, goto 2;
1839  * 5. Traverse the extent tree from the 1st extent;
1840  * 6. Above steps exit if there is no space in this RPC.
1841  */
1842 static int get_write_extents(struct osc_object *obj, cfs_list_t *rpclist)
1843 {
1844         struct client_obd *cli = osc_cli(obj);
1845         struct osc_extent *ext;
1846         int page_count = 0;
1847         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1848
1849         LASSERT(osc_object_is_locked(obj));
1850         while (!cfs_list_empty(&obj->oo_hp_exts)) {
1851                 ext = cfs_list_entry(obj->oo_hp_exts.next, struct osc_extent,
1852                                      oe_link);
1853                 LASSERT(ext->oe_state == OES_CACHE);
1854                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1855                                               &max_pages))
1856                         return page_count;
1857                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1858         }
1859         if (page_count == max_pages)
1860                 return page_count;
1861
1862         while (!cfs_list_empty(&obj->oo_urgent_exts)) {
1863                 ext = cfs_list_entry(obj->oo_urgent_exts.next,
1864                                      struct osc_extent, oe_link);
1865                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1866                                               &max_pages))
1867                         return page_count;
1868
1869                 if (!ext->oe_intree)
1870                         continue;
1871
1872                 while ((ext = next_extent(ext)) != NULL) {
1873                         if ((ext->oe_state != OES_CACHE) ||
1874                             (!cfs_list_empty(&ext->oe_link) &&
1875                              ext->oe_owner != NULL))
1876                                 continue;
1877
1878                         if (!try_to_add_extent_for_io(cli, ext, rpclist,
1879                                                       &page_count, &max_pages))
1880                                 return page_count;
1881                 }
1882         }
1883         if (page_count == max_pages)
1884                 return page_count;
1885
1886         ext = first_extent(obj);
1887         while (ext != NULL) {
1888                 if ((ext->oe_state != OES_CACHE) ||
1889                     /* this extent may be already in current rpclist */
1890                     (!cfs_list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
1891                         ext = next_extent(ext);
1892                         continue;
1893                 }
1894
1895                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1896                                               &max_pages))
1897                         return page_count;
1898
1899                 ext = next_extent(ext);
1900         }
1901         return page_count;
1902 }
1903
1904 static int
1905 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1906                    struct osc_object *osc, pdl_policy_t pol)
1907 {
1908         CFS_LIST_HEAD(rpclist);
1909         struct osc_extent *ext;
1910         struct osc_extent *tmp;
1911         struct osc_extent *first = NULL;
1912         obd_count page_count = 0;
1913         int srvlock = 0;
1914         int rc = 0;
1915         ENTRY;
1916
1917         LASSERT(osc_object_is_locked(osc));
1918
1919         page_count = get_write_extents(osc, &rpclist);
1920         LASSERT(equi(page_count == 0, cfs_list_empty(&rpclist)));
1921
1922         if (cfs_list_empty(&rpclist))
1923                 RETURN(0);
1924
1925         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
1926
1927         cfs_list_for_each_entry(ext, &rpclist, oe_link) {
1928                 LASSERT(ext->oe_state == OES_CACHE ||
1929                         ext->oe_state == OES_LOCK_DONE);
1930                 if (ext->oe_state == OES_CACHE)
1931                         osc_extent_state_set(ext, OES_LOCKING);
1932                 else
1933                         osc_extent_state_set(ext, OES_RPC);
1934         }
1935
1936         /* we're going to grab page lock, so release object lock because
1937          * lock order is page lock -> object lock. */
1938         osc_object_unlock(osc);
1939
1940         cfs_list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
1941                 if (ext->oe_state == OES_LOCKING) {
1942                         rc = osc_extent_make_ready(env, ext);
1943                         if (unlikely(rc < 0)) {
1944                                 cfs_list_del_init(&ext->oe_link);
1945                                 osc_extent_finish(env, ext, 0, rc);
1946                                 continue;
1947                         }
1948                 }
1949                 if (first == NULL) {
1950                         first = ext;
1951                         srvlock = ext->oe_srvlock;
1952                 } else {
1953                         LASSERT(srvlock == ext->oe_srvlock);
1954                 }
1955         }
1956
1957         if (!cfs_list_empty(&rpclist)) {
1958                 LASSERT(page_count > 0);
1959                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE, pol);
1960                 LASSERT(cfs_list_empty(&rpclist));
1961         }
1962
1963         osc_object_lock(osc);
1964         RETURN(rc);
1965 }
1966
1967 /**
1968  * prepare pages for ASYNC io and put pages in send queue.
1969  *
1970  * \param cmd OBD_BRW_* macroses
1971  * \param lop pending pages
1972  *
1973  * \return zero if no page added to send queue.
1974  * \return 1 if pages successfully added to send queue.
1975  * \return negative on errors.
1976  */
1977 static int
1978 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
1979                   struct osc_object *osc, pdl_policy_t pol)
1980 {
1981         struct osc_extent *ext;
1982         struct osc_extent *next;
1983         CFS_LIST_HEAD(rpclist);
1984         int page_count = 0;
1985         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1986         int rc = 0;
1987         ENTRY;
1988
1989         LASSERT(osc_object_is_locked(osc));
1990         cfs_list_for_each_entry_safe(ext, next,
1991                                      &osc->oo_reading_exts, oe_link) {
1992                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
1993                 if (!try_to_add_extent_for_io(cli, ext, &rpclist, &page_count,
1994                                               &max_pages))
1995                         break;
1996                 osc_extent_state_set(ext, OES_RPC);
1997                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1998         }
1999         LASSERT(page_count <= max_pages);
2000
2001         osc_update_pending(osc, OBD_BRW_READ, -page_count);
2002
2003         if (!cfs_list_empty(&rpclist)) {
2004                 osc_object_unlock(osc);
2005
2006                 LASSERT(page_count > 0);
2007                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ, pol);
2008                 LASSERT(cfs_list_empty(&rpclist));
2009
2010                 osc_object_lock(osc);
2011         }
2012         RETURN(rc);
2013 }
2014
2015 #define list_to_obj(list, item) ({                                            \
2016         cfs_list_t *__tmp = (list)->next;                                     \
2017         cfs_list_del_init(__tmp);                                             \
2018         cfs_list_entry(__tmp, struct osc_object, oo_##item);                  \
2019 })
2020
2021 /* This is called by osc_check_rpcs() to find which objects have pages that
2022  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2023 static struct osc_object *osc_next_obj(struct client_obd *cli)
2024 {
2025         ENTRY;
2026
2027         /* First return objects that have blocked locks so that they
2028          * will be flushed quickly and other clients can get the lock,
2029          * then objects which have pages ready to be stuffed into RPCs */
2030         if (!cfs_list_empty(&cli->cl_loi_hp_ready_list))
2031                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2032         if (!cfs_list_empty(&cli->cl_loi_ready_list))
2033                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2034
2035         /* then if we have cache waiters, return all objects with queued
2036          * writes.  This is especially important when many small files
2037          * have filled up the cache and not been fired into rpcs because
2038          * they don't pass the nr_pending/object threshhold */
2039         if (!cfs_list_empty(&cli->cl_cache_waiters) &&
2040             !cfs_list_empty(&cli->cl_loi_write_list))
2041                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2042
2043         /* then return all queued objects when we have an invalid import
2044          * so that they get flushed */
2045         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2046                 if (!cfs_list_empty(&cli->cl_loi_write_list))
2047                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2048                                            write_item));
2049                 if (!cfs_list_empty(&cli->cl_loi_read_list))
2050                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2051                                            read_item));
2052         }
2053         RETURN(NULL);
2054 }
2055
2056 /* called with the loi list lock held */
2057 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
2058                            pdl_policy_t pol)
2059 {
2060         struct osc_object *osc;
2061         int rc = 0;
2062         ENTRY;
2063
2064         while ((osc = osc_next_obj(cli)) != NULL) {
2065                 struct cl_object *obj = osc2cl(osc);
2066                 struct lu_ref_link *link;
2067
2068                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2069
2070                 if (osc_max_rpc_in_flight(cli, osc)) {
2071                         __osc_list_maint(cli, osc);
2072                         break;
2073                 }
2074
2075                 cl_object_get(obj);
2076                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2077                 link = lu_object_ref_add(&obj->co_lu, "check", cfs_current());
2078
2079                 /* attempt some read/write balancing by alternating between
2080                  * reads and writes in an object.  The makes_rpc checks here
2081                  * would be redundant if we were getting read/write work items
2082                  * instead of objects.  we don't want send_oap_rpc to drain a
2083                  * partial read pending queue when we're given this object to
2084                  * do io on writes while there are cache waiters */
2085                 osc_object_lock(osc);
2086                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2087                         rc = osc_send_write_rpc(env, cli, osc, pol);
2088                         if (rc < 0) {
2089                                 CERROR("Write request failed with %d\n", rc);
2090
2091                                 /* osc_send_write_rpc failed, mostly because of
2092                                  * memory pressure.
2093                                  *
2094                                  * It can't break here, because if:
2095                                  *  - a page was submitted by osc_io_submit, so
2096                                  *    page locked;
2097                                  *  - no request in flight
2098                                  *  - no subsequent request
2099                                  * The system will be in live-lock state,
2100                                  * because there is no chance to call
2101                                  * osc_io_unplug() and osc_check_rpcs() any
2102                                  * more. pdflush can't help in this case,
2103                                  * because it might be blocked at grabbing
2104                                  * the page lock as we mentioned.
2105                                  *
2106                                  * Anyway, continue to drain pages. */
2107                                 /* break; */
2108                         }
2109                 }
2110                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2111                         rc = osc_send_read_rpc(env, cli, osc, pol);
2112                         if (rc < 0)
2113                                 CERROR("Read request failed with %d\n", rc);
2114                 }
2115                 osc_object_unlock(osc);
2116
2117                 osc_list_maint(cli, osc);
2118                 lu_object_ref_del_at(&obj->co_lu, link, "check", cfs_current());
2119                 cl_object_put(env, obj);
2120
2121                 client_obd_list_lock(&cli->cl_loi_list_lock);
2122         }
2123 }
2124
2125 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2126                           struct osc_object *osc, pdl_policy_t pol, int async)
2127 {
2128         int has_rpcs = 1;
2129         int rc = 0;
2130
2131         client_obd_list_lock(&cli->cl_loi_list_lock);
2132         if (osc != NULL)
2133                 has_rpcs = __osc_list_maint(cli, osc);
2134         if (has_rpcs) {
2135                 if (!async) {
2136                         osc_check_rpcs(env, cli, pol);
2137                 } else {
2138                         CDEBUG(D_CACHE, "Queue writeback work for client %p.\n",
2139                                cli);
2140                         LASSERT(cli->cl_writeback_work != NULL);
2141                         rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2142                 }
2143         }
2144         client_obd_list_unlock(&cli->cl_loi_list_lock);
2145         return rc;
2146 }
2147
2148 static int osc_io_unplug_async(const struct lu_env *env,
2149                                 struct client_obd *cli, struct osc_object *osc)
2150 {
2151         /* XXX: policy is no use actually. */
2152         return osc_io_unplug0(env, cli, osc, PDL_POLICY_ROUND, 1);
2153 }
2154
2155 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
2156                    struct osc_object *osc, pdl_policy_t pol)
2157 {
2158         (void)osc_io_unplug0(env, cli, osc, pol, 0);
2159 }
2160
2161 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2162                         cfs_page_t *page, loff_t offset)
2163 {
2164         struct obd_export     *exp = osc_export(osc);
2165         struct osc_async_page *oap = &ops->ops_oap;
2166         ENTRY;
2167
2168         if (!page)
2169                 return cfs_size_round(sizeof(*oap));
2170
2171         oap->oap_magic = OAP_MAGIC;
2172         oap->oap_cli = &exp->exp_obd->u.cli;
2173         oap->oap_obj = osc;
2174
2175         oap->oap_page = page;
2176         oap->oap_obj_off = offset;
2177         LASSERT(!(offset & ~CFS_PAGE_MASK));
2178
2179         if (!client_is_remote(exp) && cfs_capable(CFS_CAP_SYS_RESOURCE))
2180                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2181
2182         CFS_INIT_LIST_HEAD(&oap->oap_pending_item);
2183         CFS_INIT_LIST_HEAD(&oap->oap_rpc_item);
2184
2185         spin_lock_init(&oap->oap_lock);
2186         CDEBUG(D_INFO, "oap %p page %p obj off "LPU64"\n",
2187                oap, page, oap->oap_obj_off);
2188         RETURN(0);
2189 }
2190
2191 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2192                        struct osc_page *ops)
2193 {
2194         struct osc_io *oio = osc_env_io(env);
2195         struct osc_extent     *ext = NULL;
2196         struct osc_async_page *oap = &ops->ops_oap;
2197         struct client_obd     *cli = oap->oap_cli;
2198         struct osc_object     *osc = oap->oap_obj;
2199         pgoff_t index;
2200         int    grants = 0;
2201         int    brw_flags = OBD_BRW_ASYNC;
2202         int    cmd = OBD_BRW_WRITE;
2203         int    need_release = 0;
2204         int    rc = 0;
2205         ENTRY;
2206
2207         if (oap->oap_magic != OAP_MAGIC)
2208                 RETURN(-EINVAL);
2209
2210         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2211                 RETURN(-EIO);
2212
2213         if (!cfs_list_empty(&oap->oap_pending_item) ||
2214             !cfs_list_empty(&oap->oap_rpc_item))
2215                 RETURN(-EBUSY);
2216
2217         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2218         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2219         if (!client_is_remote(osc_export(osc)) &&
2220             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2221                 brw_flags |= OBD_BRW_NOQUOTA;
2222                 cmd |= OBD_BRW_NOQUOTA;
2223         }
2224
2225         /* check if the file's owner/group is over quota */
2226         if (!(cmd & OBD_BRW_NOQUOTA)) {
2227                 struct cl_object *obj;
2228                 struct cl_attr   *attr;
2229                 unsigned int qid[MAXQUOTAS];
2230
2231                 obj = cl_object_top(&osc->oo_cl);
2232                 attr = &osc_env_info(env)->oti_attr;
2233
2234                 cl_object_attr_lock(obj);
2235                 rc = cl_object_attr_get(env, obj, attr);
2236                 cl_object_attr_unlock(obj);
2237
2238                 qid[USRQUOTA] = attr->cat_uid;
2239                 qid[GRPQUOTA] = attr->cat_gid;
2240                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2241                         rc = -EDQUOT;
2242                 if (rc)
2243                         RETURN(rc);
2244         }
2245
2246         oap->oap_cmd = cmd;
2247         oap->oap_page_off = ops->ops_from;
2248         oap->oap_count = ops->ops_to - ops->ops_from;
2249         oap->oap_async_flags = 0;
2250         oap->oap_brw_flags = brw_flags;
2251
2252         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2253                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2254
2255         index = oap2cl_page(oap)->cp_index;
2256
2257         /* Add this page into extent by the following steps:
2258          * 1. if there exists an active extent for this IO, mostly this page
2259          *    can be added to the active extent and sometimes we need to
2260          *    expand extent to accomodate this page;
2261          * 2. otherwise, a new extent will be allocated. */
2262
2263         ext = oio->oi_active;
2264         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2265                 /* one chunk plus extent overhead must be enough to write this
2266                  * page */
2267                 grants = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2268                 if (ext->oe_end >= index)
2269                         grants = 0;
2270
2271                 /* it doesn't need any grant to dirty this page */
2272                 client_obd_list_lock(&cli->cl_loi_list_lock);
2273                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2274                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2275                 if (rc == 0) { /* try failed */
2276                         grants = 0;
2277                         need_release = 1;
2278                 } else if (ext->oe_end < index) {
2279                         int tmp = grants;
2280                         /* try to expand this extent */
2281                         rc = osc_extent_expand(ext, index, &tmp);
2282                         if (rc < 0) {
2283                                 need_release = 1;
2284                                 /* don't free reserved grant */
2285                         } else {
2286                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2287                                                 "expanded for %lu.\n", index);
2288                                 osc_unreserve_grant(cli, grants, tmp);
2289                                 grants = 0;
2290                         }
2291                 }
2292                 rc = 0;
2293         } else if (ext != NULL) {
2294                 /* index is located outside of active extent */
2295                 need_release = 1;
2296         }
2297         if (need_release) {
2298                 osc_extent_release(env, ext);
2299                 oio->oi_active = NULL;
2300                 ext = NULL;
2301         }
2302
2303         if (ext == NULL) {
2304                 int tmp = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2305
2306                 /* try to find new extent to cover this page */
2307                 LASSERT(oio->oi_active == NULL);
2308                 /* we may have allocated grant for this page if we failed
2309                  * to expand the previous active extent. */
2310                 LASSERT(ergo(grants > 0, grants >= tmp));
2311
2312                 rc = 0;
2313                 if (grants == 0) {
2314                         /* we haven't allocated grant for this page. */
2315                         rc = osc_enter_cache(env, cli, oap, tmp);
2316                         if (rc == 0)
2317                                 grants = tmp;
2318                 }
2319
2320                 tmp = grants;
2321                 if (rc == 0) {
2322                         ext = osc_extent_find(env, osc, index, &tmp);
2323                         if (IS_ERR(ext)) {
2324                                 LASSERT(tmp == grants);
2325                                 osc_exit_cache(cli, oap);
2326                                 rc = PTR_ERR(ext);
2327                                 ext = NULL;
2328                         } else {
2329                                 oio->oi_active = ext;
2330                         }
2331                 }
2332                 if (grants > 0)
2333                         osc_unreserve_grant(cli, grants, tmp);
2334         }
2335
2336         LASSERT(ergo(rc == 0, ext != NULL));
2337         if (ext != NULL) {
2338                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2339                          ext, "index = %lu.\n", index);
2340                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2341
2342                 osc_object_lock(osc);
2343                 if (ext->oe_nr_pages == 0)
2344                         ext->oe_srvlock = ops->ops_srvlock;
2345                 else
2346                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2347                 ++ext->oe_nr_pages;
2348                 cfs_list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2349                 osc_object_unlock(osc);
2350         }
2351         RETURN(rc);
2352 }
2353
2354 int osc_teardown_async_page(const struct lu_env *env,
2355                             struct osc_object *obj, struct osc_page *ops)
2356 {
2357         struct osc_async_page *oap = &ops->ops_oap;
2358         struct osc_extent     *ext = NULL;
2359         int rc = 0;
2360         ENTRY;
2361
2362         LASSERT(oap->oap_magic == OAP_MAGIC);
2363
2364         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2365                oap, ops, oap2cl_page(oap)->cp_index);
2366
2367         osc_object_lock(obj);
2368         if (!cfs_list_empty(&oap->oap_rpc_item)) {
2369                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2370                 rc = -EBUSY;
2371         } else if (!cfs_list_empty(&oap->oap_pending_item)) {
2372                 ext = osc_extent_lookup(obj, oap2cl_page(oap)->cp_index);
2373                 /* only truncated pages are allowed to be taken out.
2374                  * See osc_extent_truncate() and osc_cache_truncate_start()
2375                  * for details. */
2376                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2377                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2378                                         oap2cl_page(oap)->cp_index);
2379                         rc = -EBUSY;
2380                 }
2381         }
2382         osc_object_unlock(obj);
2383         if (ext != NULL)
2384                 osc_extent_put(env, ext);
2385         RETURN(rc);
2386 }
2387
2388 /**
2389  * This is called when a page is picked up by kernel to write out.
2390  *
2391  * We should find out the corresponding extent and add the whole extent
2392  * into urgent list. The extent may be being truncated or used, handle it
2393  * carefully.
2394  */
2395 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2396                          struct osc_page *ops)
2397 {
2398         struct osc_extent *ext   = NULL;
2399         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2400         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2401         pgoff_t            index = cp->cp_index;
2402         struct osc_async_page *oap = &ops->ops_oap;
2403         bool unplug = false;
2404         int rc = 0;
2405         ENTRY;
2406
2407         osc_object_lock(obj);
2408         ext = osc_extent_lookup(obj, index);
2409         if (ext == NULL) {
2410                 osc_extent_tree_dump(D_ERROR, obj);
2411                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2412         }
2413
2414         switch (ext->oe_state) {
2415         case OES_RPC:
2416         case OES_LOCK_DONE:
2417                 CL_PAGE_DEBUG(D_ERROR, env, cl_page_top(cp),
2418                               "flush an in-rpc page?\n");
2419                 LASSERT(0);
2420                 break;
2421         case OES_LOCKING:
2422                 /* If we know this extent is being written out, we should abort
2423                  * so that the writer can make this page ready. Otherwise, there
2424                  * exists a deadlock problem because other process can wait for
2425                  * page writeback bit holding page lock; and meanwhile in
2426                  * vvp_page_make_ready(), we need to grab page lock before
2427                  * really sending the RPC. */
2428         case OES_TRUNC:
2429                 /* race with truncate, page will be redirtied */
2430                 GOTO(out, rc = -EAGAIN);
2431         default:
2432                 break;
2433         }
2434
2435         rc = cl_page_prep(env, io, cl_page_top(cp), CRT_WRITE);
2436         if (rc)
2437                 GOTO(out, rc);
2438
2439         spin_lock(&oap->oap_lock);
2440         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2441         spin_unlock(&oap->oap_lock);
2442
2443         if (cfs_memory_pressure_get())
2444                 ext->oe_memalloc = 1;
2445
2446         ext->oe_urgent = 1;
2447         if (ext->oe_state == OES_CACHE) {
2448                 OSC_EXTENT_DUMP(D_CACHE, ext,
2449                                 "flush page %p make it urgent.\n", oap);
2450                 if (cfs_list_empty(&ext->oe_link))
2451                         cfs_list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2452                 unplug = true;
2453         }
2454         rc = 0;
2455         EXIT;
2456
2457 out:
2458         osc_object_unlock(obj);
2459         osc_extent_put(env, ext);
2460         if (unplug)
2461                 osc_io_unplug_async(env, osc_cli(obj), obj);
2462         return rc;
2463 }
2464
2465 /**
2466  * this is called when a sync waiter receives an interruption.  Its job is to
2467  * get the caller woken as soon as possible.  If its page hasn't been put in an
2468  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2469  * desiring interruption which will forcefully complete the rpc once the rpc
2470  * has timed out.
2471  */
2472 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2473 {
2474         struct osc_async_page *oap = &ops->ops_oap;
2475         struct osc_object     *obj = oap->oap_obj;
2476         struct client_obd     *cli = osc_cli(obj);
2477         struct osc_extent     *ext;
2478         struct osc_extent     *found = NULL;
2479         cfs_list_t            *plist;
2480         pgoff_t index = oap2cl_page(oap)->cp_index;
2481         int     rc = -EBUSY;
2482         int     cmd;
2483         ENTRY;
2484
2485         LASSERT(!oap->oap_interrupted);
2486         oap->oap_interrupted = 1;
2487
2488         /* Find out the caching extent */
2489         osc_object_lock(obj);
2490         if (oap->oap_cmd & OBD_BRW_WRITE) {
2491                 plist = &obj->oo_urgent_exts;
2492                 cmd   = OBD_BRW_WRITE;
2493         } else {
2494                 plist = &obj->oo_reading_exts;
2495                 cmd   = OBD_BRW_READ;
2496         }
2497         cfs_list_for_each_entry(ext, plist, oe_link) {
2498                 if (ext->oe_start <= index && ext->oe_end >= index) {
2499                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2500                         /* For OES_LOCK_DONE state extent, it has already held
2501                          * a refcount for RPC. */
2502                         found = osc_extent_get(ext);
2503                         break;
2504                 }
2505         }
2506         if (found != NULL) {
2507                 cfs_list_del_init(&found->oe_link);
2508                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2509                 osc_object_unlock(obj);
2510
2511                 osc_extent_finish(env, found, 0, -EINTR);
2512                 osc_extent_put(env, found);
2513                 rc = 0;
2514         } else {
2515                 osc_object_unlock(obj);
2516                 /* ok, it's been put in an rpc. only one oap gets a request
2517                  * reference */
2518                 if (oap->oap_request != NULL) {
2519                         ptlrpc_mark_interrupted(oap->oap_request);
2520                         ptlrpcd_wake(oap->oap_request);
2521                         ptlrpc_req_finished(oap->oap_request);
2522                         oap->oap_request = NULL;
2523                 }
2524         }
2525
2526         osc_list_maint(cli, obj);
2527         RETURN(rc);
2528 }
2529
2530 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
2531                          cfs_list_t *list, int cmd, int brw_flags)
2532 {
2533         struct client_obd     *cli = osc_cli(obj);
2534         struct osc_extent     *ext;
2535         struct osc_async_page *oap;
2536         int     page_count = 0;
2537         int     mppr       = cli->cl_max_pages_per_rpc;
2538         pgoff_t start      = CL_PAGE_EOF;
2539         pgoff_t end        = 0;
2540         ENTRY;
2541
2542         cfs_list_for_each_entry(oap, list, oap_pending_item) {
2543                 struct cl_page *cp = oap2cl_page(oap);
2544                 if (cp->cp_index > end)
2545                         end = cp->cp_index;
2546                 if (cp->cp_index < start)
2547                         start = cp->cp_index;
2548                 ++page_count;
2549                 mppr <<= (page_count > mppr);
2550         }
2551
2552         ext = osc_extent_alloc(obj);
2553         if (ext == NULL) {
2554                 cfs_list_for_each_entry(oap, list, oap_pending_item) {
2555                         cfs_list_del_init(&oap->oap_pending_item);
2556                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2557                 }
2558                 RETURN(-ENOMEM);
2559         }
2560
2561         ext->oe_rw = !!(cmd & OBD_BRW_READ);
2562         ext->oe_urgent = 1;
2563         ext->oe_start = start;
2564         ext->oe_end = ext->oe_max_end = end;
2565         ext->oe_obj = obj;
2566         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2567         ext->oe_nr_pages = page_count;
2568         ext->oe_mppr = mppr;
2569         cfs_list_splice_init(list, &ext->oe_pages);
2570
2571         osc_object_lock(obj);
2572         /* Reuse the initial refcount for RPC, don't drop it */
2573         osc_extent_state_set(ext, OES_LOCK_DONE);
2574         if (cmd & OBD_BRW_WRITE) {
2575                 cfs_list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2576                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2577         } else {
2578                 cfs_list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2579                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2580         }
2581         osc_object_unlock(obj);
2582
2583         osc_io_unplug(env, cli, obj, PDL_POLICY_ROUND);
2584         RETURN(0);
2585 }
2586
2587 /**
2588  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2589  */
2590 int osc_cache_truncate_start(const struct lu_env *env, struct osc_io *oio,
2591                              struct osc_object *obj, __u64 size)
2592 {
2593         struct client_obd *cli = osc_cli(obj);
2594         struct osc_extent *ext;
2595         struct osc_extent *waiting = NULL;
2596         pgoff_t index;
2597         CFS_LIST_HEAD(list);
2598         int result = 0;
2599         bool partial;
2600         ENTRY;
2601
2602         /* pages with index greater or equal to index will be truncated. */
2603         index = cl_index(osc2cl(obj), size);
2604         partial = size > cl_offset(osc2cl(obj), index);
2605
2606 again:
2607         osc_object_lock(obj);
2608         ext = osc_extent_search(obj, index);
2609         if (ext == NULL)
2610                 ext = first_extent(obj);
2611         else if (ext->oe_end < index)
2612                 ext = next_extent(ext);
2613         while (ext != NULL) {
2614                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2615
2616                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2617                         /* if ext is in urgent state, it means there must exist
2618                          * a page already having been flushed by write_page().
2619                          * We have to wait for this extent because we can't
2620                          * truncate that page. */
2621                         LASSERT(!ext->oe_hp);
2622                         OSC_EXTENT_DUMP(D_CACHE, ext,
2623                                         "waiting for busy extent\n");
2624                         waiting = osc_extent_get(ext);
2625                         break;
2626                 }
2627
2628                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:"LPU64".\n", size);
2629
2630                 osc_extent_get(ext);
2631                 if (ext->oe_state == OES_ACTIVE) {
2632                         /* though we grab inode mutex for write path, but we
2633                          * release it before releasing extent(in osc_io_end()),
2634                          * so there is a race window that an extent is still
2635                          * in OES_ACTIVE when truncate starts. */
2636                         LASSERT(!ext->oe_trunc_pending);
2637                         ext->oe_trunc_pending = 1;
2638                 } else {
2639                         EASSERT(ext->oe_state == OES_CACHE, ext);
2640                         osc_extent_state_set(ext, OES_TRUNC);
2641                         osc_update_pending(obj, OBD_BRW_WRITE,
2642                                            -ext->oe_nr_pages);
2643                 }
2644                 EASSERT(cfs_list_empty(&ext->oe_link), ext);
2645                 cfs_list_add_tail(&ext->oe_link, &list);
2646
2647                 ext = next_extent(ext);
2648         }
2649         osc_object_unlock(obj);
2650
2651         osc_list_maint(cli, obj);
2652
2653         while (!cfs_list_empty(&list)) {
2654                 int rc;
2655
2656                 ext = cfs_list_entry(list.next, struct osc_extent, oe_link);
2657                 cfs_list_del_init(&ext->oe_link);
2658
2659                 /* extent may be in OES_ACTIVE state because inode mutex
2660                  * is released before osc_io_end() in file write case */
2661                 if (ext->oe_state != OES_TRUNC)
2662                         osc_extent_wait(env, ext, OES_TRUNC);
2663
2664                 rc = osc_extent_truncate(ext, index, partial);
2665                 if (rc < 0) {
2666                         if (result == 0)
2667                                 result = rc;
2668
2669                         OSC_EXTENT_DUMP(D_ERROR, ext,
2670                                         "truncate error %d\n", rc);
2671                 } else if (ext->oe_nr_pages == 0) {
2672                         osc_extent_remove(ext);
2673                 } else {
2674                         /* this must be an overlapped extent which means only
2675                          * part of pages in this extent have been truncated.
2676                          */
2677                         EASSERTF(ext->oe_start <= index, ext,
2678                                  "trunc index = %lu/%d.\n", index, partial);
2679                         /* fix index to skip this partially truncated extent */
2680                         index = ext->oe_end + 1;
2681                         partial = false;
2682
2683                         /* we need to hold this extent in OES_TRUNC state so
2684                          * that no writeback will happen. This is to avoid
2685                          * BUG 17397. */
2686                         LASSERT(oio->oi_trunc == NULL);
2687                         oio->oi_trunc = osc_extent_get(ext);
2688                         OSC_EXTENT_DUMP(D_CACHE, ext,
2689                                         "trunc at "LPU64"\n", size);
2690                 }
2691                 osc_extent_put(env, ext);
2692         }
2693         if (waiting != NULL) {
2694                 int rc;
2695
2696                 /* ignore the result of osc_extent_wait the write initiator
2697                  * should take care of it. */
2698                 rc = osc_extent_wait(env, waiting, OES_INV);
2699                 if (rc < 0)
2700                         OSC_EXTENT_DUMP(D_CACHE, ext, "wait error: %d.\n", rc);
2701
2702                 osc_extent_put(env, waiting);
2703                 waiting = NULL;
2704                 goto again;
2705         }
2706         RETURN(result);
2707 }
2708
2709 /**
2710  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2711  */
2712 void osc_cache_truncate_end(const struct lu_env *env, struct osc_io *oio,
2713                             struct osc_object *obj)
2714 {
2715         struct osc_extent *ext = oio->oi_trunc;
2716
2717         oio->oi_trunc = NULL;
2718         if (ext != NULL) {
2719                 bool unplug = false;
2720
2721                 EASSERT(ext->oe_nr_pages > 0, ext);
2722                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2723                 EASSERT(!ext->oe_urgent, ext);
2724
2725                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2726                 osc_object_lock(obj);
2727                 osc_extent_state_set(ext, OES_CACHE);
2728                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2729                         ext->oe_urgent = 1;
2730                         cfs_list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2731                         unplug = true;
2732                 }
2733                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2734                 osc_object_unlock(obj);
2735                 osc_extent_put(env, ext);
2736
2737                 if (unplug)
2738                         osc_io_unplug_async(env, osc_cli(obj), obj);
2739         }
2740 }
2741
2742 /**
2743  * Wait for extents in a specific range to be written out.
2744  * The caller must have called osc_cache_writeback_range() to issue IO
2745  * otherwise it will take a long time for this function to finish.
2746  *
2747  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2748  * nobody else can dirty this range of file while we're waiting for
2749  * extents to be written.
2750  */
2751 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2752                          pgoff_t start, pgoff_t end)
2753 {
2754         struct osc_extent *ext;
2755         pgoff_t index = start;
2756         int     result = 0;
2757         ENTRY;
2758
2759 again:
2760         osc_object_lock(obj);
2761         ext = osc_extent_search(obj, index);
2762         if (ext == NULL)
2763                 ext = first_extent(obj);
2764         else if (ext->oe_end < index)
2765                 ext = next_extent(ext);
2766         while (ext != NULL) {
2767                 int rc;
2768
2769                 if (ext->oe_start > end)
2770                         break;
2771
2772                 if (!ext->oe_fsync_wait) {
2773                         ext = next_extent(ext);
2774                         continue;
2775                 }
2776
2777                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2778                              ext->oe_hp || ext->oe_urgent), ext);
2779                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2780                              !ext->oe_hp && ext->oe_urgent), ext);
2781
2782                 index = ext->oe_end + 1;
2783                 osc_extent_get(ext);
2784                 osc_object_unlock(obj);
2785
2786                 rc = osc_extent_wait(env, ext, OES_INV);
2787                 if (result == 0)
2788                         result = rc;
2789                 osc_extent_put(env, ext);
2790                 goto again;
2791         }
2792         osc_object_unlock(obj);
2793
2794         OSC_IO_DEBUG(obj, "sync file range.\n");
2795         RETURN(result);
2796 }
2797
2798 /**
2799  * Called to write out a range of osc object.
2800  *
2801  * @hp     : should be set this is caused by lock cancel;
2802  * @discard: is set if dirty pages should be dropped - file will be deleted or
2803  *         truncated, this implies there is no partially discarding extents.
2804  *
2805  * Return how many pages will be issued, or error code if error occurred.
2806  */
2807 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2808                               pgoff_t start, pgoff_t end, int hp, int discard)
2809 {
2810         struct osc_extent *ext;
2811         CFS_LIST_HEAD(discard_list);
2812         bool unplug = false;
2813         int result = 0;
2814         ENTRY;
2815
2816         osc_object_lock(obj);
2817         ext = osc_extent_search(obj, start);
2818         if (ext == NULL)
2819                 ext = first_extent(obj);
2820         else if (ext->oe_end < start)
2821                 ext = next_extent(ext);
2822         while (ext != NULL) {
2823                 if (ext->oe_start > end)
2824                         break;
2825
2826                 ext->oe_fsync_wait = 1;
2827                 switch (ext->oe_state) {
2828                 case OES_CACHE:
2829                         result += ext->oe_nr_pages;
2830                         if (!discard) {
2831                                 cfs_list_t *list = NULL;
2832                                 if (hp) {
2833                                         EASSERT(!ext->oe_hp, ext);
2834                                         ext->oe_hp = 1;
2835                                         list = &obj->oo_hp_exts;
2836                                 } else if (!ext->oe_urgent) {
2837                                         ext->oe_urgent = 1;
2838                                         list = &obj->oo_urgent_exts;
2839                                 }
2840                                 if (list != NULL)
2841                                         cfs_list_move_tail(&ext->oe_link, list);
2842                                 unplug = true;
2843                         } else {
2844                                 /* the only discarder is lock cancelling, so
2845                                  * [start, end] must contain this extent */
2846                                 EASSERT(ext->oe_start >= start &&
2847                                         ext->oe_max_end <= end, ext);
2848                                 osc_extent_state_set(ext, OES_LOCKING);
2849                                 ext->oe_owner = cfs_current();
2850                                 cfs_list_move_tail(&ext->oe_link,
2851                                                    &discard_list);
2852                                 osc_update_pending(obj, OBD_BRW_WRITE,
2853                                                    -ext->oe_nr_pages);
2854                         }
2855                         break;
2856                 case OES_ACTIVE:
2857                         /* It's pretty bad to wait for ACTIVE extents, because
2858                          * we don't know how long we will wait for it to be
2859                          * flushed since it may be blocked at awaiting more
2860                          * grants. We do this for the correctness of fsync. */
2861                         LASSERT(hp == 0 && discard == 0);
2862                         ext->oe_urgent = 1;
2863                         break;
2864                 case OES_TRUNC:
2865                         /* this extent is being truncated, can't do anything
2866                          * for it now. it will be set to urgent after truncate
2867                          * is finished in osc_cache_truncate_end(). */
2868                 default:
2869                         break;
2870                 }
2871                 ext = next_extent(ext);
2872         }
2873         osc_object_unlock(obj);
2874
2875         LASSERT(ergo(!discard, cfs_list_empty(&discard_list)));
2876         if (!cfs_list_empty(&discard_list)) {
2877                 struct osc_extent *tmp;
2878                 int rc;
2879
2880                 osc_list_maint(osc_cli(obj), obj);
2881                 cfs_list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
2882                         cfs_list_del_init(&ext->oe_link);
2883                         EASSERT(ext->oe_state == OES_LOCKING, ext);
2884
2885                         /* Discard caching pages. We don't actually write this
2886                          * extent out but we complete it as if we did. */
2887                         rc = osc_extent_make_ready(env, ext);
2888                         if (unlikely(rc < 0)) {
2889                                 OSC_EXTENT_DUMP(D_ERROR, ext,
2890                                                 "make_ready returned %d\n", rc);
2891                                 if (result >= 0)
2892                                         result = rc;
2893                         }
2894
2895                         /* finish the extent as if the pages were sent */
2896                         osc_extent_finish(env, ext, 0, 0);
2897                 }
2898         }
2899
2900         if (unplug)
2901                 osc_io_unplug(env, osc_cli(obj), obj, PDL_POLICY_ROUND);
2902
2903         if (hp || discard) {
2904                 int rc;
2905                 rc = osc_cache_wait_range(env, obj, start, end);
2906                 if (result >= 0 && rc < 0)
2907                         result = rc;
2908         }
2909
2910         OSC_IO_DEBUG(obj, "cache page out.\n");
2911         RETURN(result);
2912 }
2913
2914 /** @} osc */