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[fs/lustre-release.git] / lustre / obdecho / echo.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) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
28  * Use is subject to license terms.
29  *
30  * Copyright (c) 2010, 2013, Intel Corporation.
31  */
32 /*
33  * This file is part of Lustre, http://www.lustre.org/
34  * Lustre is a trademark of Sun Microsystems, Inc.
35  *
36  * lustre/obdecho/echo.c
37  *
38  * Author: Peter Braam <braam@clusterfs.com>
39  * Author: Andreas Dilger <adilger@clusterfs.com>
40  */
41
42 #define DEBUG_SUBSYSTEM S_ECHO
43
44 #include <obd_support.h>
45 #include <obd_class.h>
46 #include <lustre_debug.h>
47 #include <lustre_dlm.h>
48 #include <lprocfs_status.h>
49
50 #include "echo_internal.h"
51
52 /* The echo objid needs to be below 2^32, because regular FID numbers are
53  * limited to 2^32 objects in f_oid for the FID_SEQ_ECHO range. b=23335 */
54 #define ECHO_INIT_OID        0x10000000ULL
55 #define ECHO_HANDLE_MAGIC    0xabcd0123fedc9876ULL
56
57 #define ECHO_PERSISTENT_PAGES (ECHO_PERSISTENT_SIZE >> CFS_PAGE_SHIFT)
58 static cfs_page_t *echo_persistent_pages[ECHO_PERSISTENT_PAGES];
59
60 enum {
61         LPROC_ECHO_READ_BYTES = 1,
62         LPROC_ECHO_WRITE_BYTES = 2,
63         LPROC_ECHO_LAST = LPROC_ECHO_WRITE_BYTES +1
64 };
65
66 static int echo_connect(const struct lu_env *env,
67                         struct obd_export **exp, struct obd_device *obd,
68                         struct obd_uuid *cluuid, struct obd_connect_data *data,
69                         void *localdata)
70 {
71         struct lustre_handle conn = { 0 };
72         int rc;
73
74         data->ocd_connect_flags &= ECHO_CONNECT_SUPPORTED;
75         rc = class_connect(&conn, obd, cluuid);
76         if (rc) {
77                 CERROR("can't connect %d\n", rc);
78                 return rc;
79         }
80         *exp = class_conn2export(&conn);
81
82         return 0;
83 }
84
85 static int echo_disconnect(struct obd_export *exp)
86 {
87         LASSERT (exp != NULL);
88
89         return server_disconnect_export(exp);
90 }
91
92 static int echo_init_export(struct obd_export *exp)
93 {
94         return ldlm_init_export(exp);
95 }
96
97 static int echo_destroy_export(struct obd_export *exp)
98 {
99         ENTRY;
100
101         target_destroy_export(exp);
102         ldlm_destroy_export(exp);
103
104         RETURN(0);
105 }
106
107  static __u64 echo_next_id(struct obd_device *obddev)
108 {
109         obd_id id;
110
111         spin_lock(&obddev->u.echo.eo_lock);
112         id = ++obddev->u.echo.eo_lastino;
113         spin_unlock(&obddev->u.echo.eo_lock);
114
115         return id;
116 }
117
118 static int echo_create(const struct lu_env *env, struct obd_export *exp,
119                        struct obdo *oa, struct lov_stripe_md **ea,
120                        struct obd_trans_info *oti)
121 {
122         struct obd_device *obd = class_exp2obd(exp);
123
124         if (!obd) {
125                 CERROR("invalid client cookie "LPX64"\n",
126                        exp->exp_handle.h_cookie);
127                 return -EINVAL;
128         }
129
130         if (!(oa->o_mode && S_IFMT)) {
131                 CERROR("echo obd: no type!\n");
132                 return -ENOENT;
133         }
134
135         if (!(oa->o_valid & OBD_MD_FLTYPE)) {
136                 CERROR("invalid o_valid "LPX64"\n", oa->o_valid);
137                 return -EINVAL;
138         }
139
140         ostid_set_seq_echo(&oa->o_oi);
141         ostid_set_id(&oa->o_oi, echo_next_id(obd));
142         oa->o_valid = OBD_MD_FLID;
143
144         return 0;
145 }
146
147 static int echo_destroy(const struct lu_env *env, struct obd_export *exp,
148                         struct obdo *oa, struct lov_stripe_md *ea,
149                         struct obd_trans_info *oti, struct obd_export *md_exp,
150                         void *capa)
151 {
152         struct obd_device *obd = class_exp2obd(exp);
153
154         ENTRY;
155         if (!obd) {
156                 CERROR("invalid client cookie "LPX64"\n",
157                        exp->exp_handle.h_cookie);
158                 RETURN(-EINVAL);
159         }
160
161         if (!(oa->o_valid & OBD_MD_FLID)) {
162                 CERROR("obdo missing FLID valid flag: "LPX64"\n", oa->o_valid);
163                 RETURN(-EINVAL);
164         }
165
166         if (ostid_id(&oa->o_oi) > obd->u.echo.eo_lastino ||
167             ostid_id(&oa->o_oi) < ECHO_INIT_OID) {
168                 CERROR("bad destroy objid: "DOSTID"\n", POSTID(&oa->o_oi));
169                 RETURN(-EINVAL);
170         }
171
172         RETURN(0);
173 }
174
175 static int echo_getattr(const struct lu_env *env, struct obd_export *exp,
176                         struct obd_info *oinfo)
177 {
178         struct obd_device *obd = class_exp2obd(exp);
179         obd_id id = ostid_id(&oinfo->oi_oa->o_oi);
180
181         ENTRY;
182         if (!obd) {
183                 CERROR("invalid client cookie "LPX64"\n",
184                        exp->exp_handle.h_cookie);
185                 RETURN(-EINVAL);
186         }
187
188         if (!(oinfo->oi_oa->o_valid & OBD_MD_FLID)) {
189                 CERROR("obdo missing FLID valid flag: "LPX64"\n",
190                        oinfo->oi_oa->o_valid);
191                 RETURN(-EINVAL);
192         }
193
194         obdo_cpy_md(oinfo->oi_oa, &obd->u.echo.eo_oa, oinfo->oi_oa->o_valid);
195         ostid_set_seq_echo(&oinfo->oi_oa->o_oi);
196         ostid_set_id(&oinfo->oi_oa->o_oi, id);
197
198         RETURN(0);
199 }
200
201 static int echo_setattr(const struct lu_env *env, struct obd_export *exp,
202                         struct obd_info *oinfo, struct obd_trans_info *oti)
203 {
204         struct obd_device *obd = class_exp2obd(exp);
205
206         ENTRY;
207         if (!obd) {
208                 CERROR("invalid client cookie "LPX64"\n",
209                        exp->exp_handle.h_cookie);
210                 RETURN(-EINVAL);
211         }
212
213         if (!(oinfo->oi_oa->o_valid & OBD_MD_FLID)) {
214                 CERROR("obdo missing FLID valid flag: "LPX64"\n",
215                        oinfo->oi_oa->o_valid);
216                 RETURN(-EINVAL);
217         }
218
219         memcpy(&obd->u.echo.eo_oa, oinfo->oi_oa, sizeof(*oinfo->oi_oa));
220
221         if (ostid_id(&oinfo->oi_oa->o_oi) & 4) {
222                 /* Save lock to force ACKed reply */
223                 ldlm_lock_addref (&obd->u.echo.eo_nl_lock, LCK_NL);
224                 oti->oti_ack_locks[0].mode = LCK_NL;
225                 oti->oti_ack_locks[0].lock = obd->u.echo.eo_nl_lock;
226         }
227
228         RETURN(0);
229 }
230
231 static void
232 echo_page_debug_setup(cfs_page_t *page, int rw, obd_id id,
233                       __u64 offset, int len)
234 {
235         int   page_offset = offset & ~CFS_PAGE_MASK;
236         char *addr        = ((char *)cfs_kmap(page)) + page_offset;
237
238         if (len % OBD_ECHO_BLOCK_SIZE != 0)
239                 CERROR("Unexpected block size %d\n", len);
240
241         while (len > 0) {
242                 if (rw & OBD_BRW_READ)
243                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
244                                           offset, id);
245                 else
246                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
247                                           0xecc0ecc0ecc0ecc0ULL,
248                                           0xecc0ecc0ecc0ecc0ULL);
249
250                 addr   += OBD_ECHO_BLOCK_SIZE;
251                 offset += OBD_ECHO_BLOCK_SIZE;
252                 len    -= OBD_ECHO_BLOCK_SIZE;
253         }
254
255         cfs_kunmap(page);
256 }
257
258 static int
259 echo_page_debug_check(cfs_page_t *page, obd_id id,
260                       __u64 offset, int len)
261 {
262         int   page_offset = offset & ~CFS_PAGE_MASK;
263         char *addr        = ((char *)cfs_kmap(page)) + page_offset;
264         int   rc          = 0;
265         int   rc2;
266
267         if (len % OBD_ECHO_BLOCK_SIZE != 0)
268                 CERROR("Unexpected block size %d\n", len);
269
270         while (len > 0) {
271                 rc2 = block_debug_check("echo", addr, OBD_ECHO_BLOCK_SIZE,
272                                         offset, id);
273
274                 if (rc2 != 0 && rc == 0)
275                         rc = rc2;
276
277                 addr   += OBD_ECHO_BLOCK_SIZE;
278                 offset += OBD_ECHO_BLOCK_SIZE;
279                 len    -= OBD_ECHO_BLOCK_SIZE;
280         }
281
282         cfs_kunmap(page);
283
284         return (rc);
285 }
286
287 /* This allows us to verify that desc_private is passed unmolested */
288 #define DESC_PRIV 0x10293847
289
290 static int echo_map_nb_to_lb(struct obdo *oa, struct obd_ioobj *obj,
291                              struct niobuf_remote *nb, int *pages,
292                              struct niobuf_local *lb, int cmd, int *left)
293 {
294         int gfp_mask = (ostid_id(&obj->ioo_oid) & 1) ?
295                         CFS_ALLOC_HIGHUSER : CFS_ALLOC_STD;
296         int ispersistent = ostid_id(&obj->ioo_oid) == ECHO_PERSISTENT_OBJID;
297         int debug_setup = (!ispersistent &&
298                            (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
299                            (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
300         struct niobuf_local *res = lb;
301         obd_off offset = nb->offset;
302         int len = nb->len;
303
304         while (len > 0) {
305                 int plen = CFS_PAGE_SIZE - (offset & (CFS_PAGE_SIZE-1));
306                 if (len < plen)
307                         plen = len;
308
309                 /* check for local buf overflow */
310                 if (*left == 0)
311                         return -EINVAL;
312
313                 res->lnb_file_offset = offset;
314                 res->len = plen;
315                 LASSERT((res->lnb_file_offset & ~CFS_PAGE_MASK) + res->len <=
316                         CFS_PAGE_SIZE);
317
318                 if (ispersistent &&
319                     ((res->lnb_file_offset >> CFS_PAGE_SHIFT) <
320                       ECHO_PERSISTENT_PAGES)) {
321                         res->page =
322                                 echo_persistent_pages[res->lnb_file_offset >>
323                                                       CFS_PAGE_SHIFT];
324                         /* Take extra ref so __free_pages() can be called OK */
325                         cfs_get_page (res->page);
326                 } else {
327                         OBD_PAGE_ALLOC(res->page, gfp_mask);
328                         if (res->page == NULL) {
329                                 CERROR("can't get page for id " DOSTID"\n",
330                                        POSTID(&obj->ioo_oid));
331                                 return -ENOMEM;
332                         }
333                 }
334
335                 CDEBUG(D_PAGE, "$$$$ get page %p @ "LPU64" for %d\n",
336                        res->page, res->lnb_file_offset, res->len);
337
338                 if (cmd & OBD_BRW_READ)
339                         res->rc = res->len;
340
341                 if (debug_setup)
342                         echo_page_debug_setup(res->page, cmd,
343                                               ostid_id(&obj->ioo_oid),
344                                               res->lnb_file_offset, res->len);
345
346                 offset += plen;
347                 len -= plen;
348                 res++;
349
350                 (*left)--;
351                 (*pages)++;
352         }
353
354         return 0;
355 }
356
357 static int echo_finalize_lb(struct obdo *oa, struct obd_ioobj *obj,
358                             struct niobuf_remote *rb, int *pgs,
359                             struct niobuf_local *lb, int verify)
360 {
361         struct niobuf_local *res = lb;
362         obd_off start  = rb->offset >> CFS_PAGE_SHIFT;
363         obd_off end    = (rb->offset + rb->len + CFS_PAGE_SIZE - 1) >> CFS_PAGE_SHIFT;
364         int     count  = (int)(end - start);
365         int     rc     = 0;
366         int     i;
367
368         for (i = 0; i < count; i++, (*pgs) ++, res++) {
369                 cfs_page_t *page = res->page;
370                 void       *addr;
371
372                 if (page == NULL) {
373                         CERROR("null page objid "LPU64":%p, buf %d/%d\n",
374                                ostid_id(&obj->ioo_oid), page, i,
375                                obj->ioo_bufcnt);
376                         return -EFAULT;
377                 }
378
379                 addr = cfs_kmap(page);
380
381                 CDEBUG(D_PAGE, "$$$$ use page %p, addr %p@"LPU64"\n",
382                        res->page, addr, res->lnb_file_offset);
383
384                 if (verify) {
385                         int vrc = echo_page_debug_check(page,
386                                                         ostid_id(&obj->ioo_oid),
387                                                         res->lnb_file_offset,
388                                                         res->len);
389                         /* check all the pages always */
390                         if (vrc != 0 && rc == 0)
391                                 rc = vrc;
392                 }
393
394                 cfs_kunmap(page);
395                 /* NB see comment above regarding persistent pages */
396                 OBD_PAGE_FREE(page);
397         }
398
399         return rc;
400 }
401
402 static int echo_preprw(const struct lu_env *env, int cmd,
403                        struct obd_export *export, struct obdo *oa,
404                        int objcount, struct obd_ioobj *obj,
405                        struct niobuf_remote *nb, int *pages,
406                        struct niobuf_local *res, struct obd_trans_info *oti,
407                        struct lustre_capa *unused)
408 {
409         struct obd_device *obd;
410         int tot_bytes = 0;
411         int rc = 0;
412         int i, left;
413         ENTRY;
414
415         obd = export->exp_obd;
416         if (obd == NULL)
417                 RETURN(-EINVAL);
418
419         /* Temp fix to stop falling foul of osc_announce_cached() */
420         oa->o_valid &= ~(OBD_MD_FLBLOCKS | OBD_MD_FLGRANT);
421
422         memset(res, 0, sizeof(*res) * *pages);
423
424         CDEBUG(D_PAGE, "%s %d obdos with %d IOs\n",
425                cmd == OBD_BRW_READ ? "reading" : "writing", objcount, *pages);
426
427         if (oti)
428                 oti->oti_handle = (void *)DESC_PRIV;
429
430         left = *pages;
431         *pages = 0;
432
433         for (i = 0; i < objcount; i++, obj++) {
434                 int j;
435
436                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, nb++) {
437
438                         rc = echo_map_nb_to_lb(oa, obj, nb, pages,
439                                                res + *pages, cmd, &left);
440                         if (rc)
441                                 GOTO(preprw_cleanup, rc);
442
443                         tot_bytes += nb->len;
444                 }
445         }
446
447         cfs_atomic_add(*pages, &obd->u.echo.eo_prep);
448
449         if (cmd & OBD_BRW_READ)
450                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_READ_BYTES,
451                                     tot_bytes);
452         else
453                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
454                                     tot_bytes);
455
456         CDEBUG(D_PAGE, "%d pages allocated after prep\n",
457                cfs_atomic_read(&obd->u.echo.eo_prep));
458
459         RETURN(0);
460
461 preprw_cleanup:
462         /* It is possible that we would rather handle errors by  allow
463          * any already-set-up pages to complete, rather than tearing them
464          * all down again.  I believe that this is what the in-kernel
465          * prep/commit operations do.
466          */
467         CERROR("cleaning up %u pages (%d obdos)\n", *pages, objcount);
468         for (i = 0; i < *pages; i++) {
469                 cfs_kunmap(res[i].page);
470                 /* NB if this is a persistent page, __free_pages will just
471                  * lose the extra ref gained above */
472                 OBD_PAGE_FREE(res[i].page);
473                 res[i].page = NULL;
474                 cfs_atomic_dec(&obd->u.echo.eo_prep);
475         }
476
477         return rc;
478 }
479
480 static int echo_commitrw(const struct lu_env *env, int cmd,
481                          struct obd_export *export, struct obdo *oa,
482                          int objcount, struct obd_ioobj *obj,
483                          struct niobuf_remote *rb, int niocount,
484                          struct niobuf_local *res, struct obd_trans_info *oti,
485                          int rc)
486 {
487         struct obd_device *obd;
488         int pgs = 0;
489         int i;
490         ENTRY;
491
492         obd = export->exp_obd;
493         if (obd == NULL)
494                 RETURN(-EINVAL);
495
496         if (rc)
497                 GOTO(commitrw_cleanup, rc);
498
499         if ((cmd & OBD_BRW_RWMASK) == OBD_BRW_READ) {
500                 CDEBUG(D_PAGE, "reading %d obdos with %d IOs\n",
501                        objcount, niocount);
502         } else {
503                 CDEBUG(D_PAGE, "writing %d obdos with %d IOs\n",
504                        objcount, niocount);
505         }
506
507         if (niocount && res == NULL) {
508                 CERROR("NULL res niobuf with niocount %d\n", niocount);
509                 RETURN(-EINVAL);
510         }
511
512         LASSERT(oti == NULL || oti->oti_handle == (void *)DESC_PRIV);
513
514         for (i = 0; i < objcount; i++, obj++) {
515                 int verify = (rc == 0 &&
516                              ostid_id(&obj->ioo_oid) != ECHO_PERSISTENT_OBJID &&
517                               (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
518                               (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
519                 int j;
520
521                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, rb++) {
522                         int vrc = echo_finalize_lb(oa, obj, rb, &pgs, &res[pgs],
523                                                    verify);
524                         if (vrc == 0)
525                                 continue;
526
527                         if (vrc == -EFAULT)
528                                 GOTO(commitrw_cleanup, rc = vrc);
529
530                         if (rc == 0)
531                                 rc = vrc;
532                 }
533
534         }
535
536         cfs_atomic_sub(pgs, &obd->u.echo.eo_prep);
537
538         CDEBUG(D_PAGE, "%d pages remain after commit\n",
539                cfs_atomic_read(&obd->u.echo.eo_prep));
540         RETURN(rc);
541
542 commitrw_cleanup:
543         cfs_atomic_sub(pgs, &obd->u.echo.eo_prep);
544
545         CERROR("cleaning up %d pages (%d obdos)\n",
546                niocount - pgs - 1, objcount);
547
548         while (pgs < niocount) {
549                 cfs_page_t *page = res[pgs++].page;
550
551                 if (page == NULL)
552                         continue;
553
554                 /* NB see comment above regarding persistent pages */
555                 OBD_PAGE_FREE(page);
556                 cfs_atomic_dec(&obd->u.echo.eo_prep);
557         }
558         return rc;
559 }
560
561 static int echo_setup(struct obd_device *obd, struct lustre_cfg *lcfg)
562 {
563         struct lprocfs_static_vars lvars;
564         int                        rc;
565         __u64                      lock_flags = 0;
566         struct ldlm_res_id         res_id = {.name = {1}};
567         char                       ns_name[48];
568         ENTRY;
569
570         obd->u.echo.eo_obt.obt_magic = OBT_MAGIC;
571         spin_lock_init(&obd->u.echo.eo_lock);
572         obd->u.echo.eo_lastino = ECHO_INIT_OID;
573
574         sprintf(ns_name, "echotgt-%s", obd->obd_uuid.uuid);
575         obd->obd_namespace = ldlm_namespace_new(obd, ns_name,
576                                                 LDLM_NAMESPACE_SERVER,
577                                                 LDLM_NAMESPACE_MODEST,
578                                                 LDLM_NS_TYPE_OST);
579         if (obd->obd_namespace == NULL) {
580                 LBUG();
581                 RETURN(-ENOMEM);
582         }
583
584         rc = ldlm_cli_enqueue_local(obd->obd_namespace, &res_id, LDLM_PLAIN,
585                                     NULL, LCK_NL, &lock_flags, NULL,
586                                     ldlm_completion_ast, NULL, NULL, 0,
587                                     LVB_T_NONE, NULL, &obd->u.echo.eo_nl_lock);
588         LASSERT (rc == ELDLM_OK);
589
590         lprocfs_echo_init_vars(&lvars);
591         if (lprocfs_obd_setup(obd, lvars.obd_vars) == 0 &&
592             lprocfs_alloc_obd_stats(obd, LPROC_ECHO_LAST) == 0) {
593                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_READ_BYTES,
594                                      LPROCFS_CNTR_AVGMINMAX,
595                                      "read_bytes", "bytes");
596                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
597                                      LPROCFS_CNTR_AVGMINMAX,
598                                      "write_bytes", "bytes");
599         }
600
601         ptlrpc_init_client (LDLM_CB_REQUEST_PORTAL, LDLM_CB_REPLY_PORTAL,
602                             "echo_ldlm_cb_client", &obd->obd_ldlm_client);
603         RETURN(0);
604 }
605
606 static int echo_cleanup(struct obd_device *obd)
607 {
608         int leaked;
609         ENTRY;
610
611         lprocfs_obd_cleanup(obd);
612         lprocfs_free_obd_stats(obd);
613
614         ldlm_lock_decref(&obd->u.echo.eo_nl_lock, LCK_NL);
615
616         /* XXX Bug 3413; wait for a bit to ensure the BL callback has
617          * happened before calling ldlm_namespace_free() */
618         cfs_schedule_timeout_and_set_state(CFS_TASK_UNINT, cfs_time_seconds(1));
619
620         ldlm_namespace_free(obd->obd_namespace, NULL, obd->obd_force);
621         obd->obd_namespace = NULL;
622
623         leaked = cfs_atomic_read(&obd->u.echo.eo_prep);
624         if (leaked != 0)
625                 CERROR("%d prep/commitrw pages leaked\n", leaked);
626
627         RETURN(0);
628 }
629
630 struct obd_ops echo_obd_ops = {
631         .o_owner           = THIS_MODULE,
632         .o_connect         = echo_connect,
633         .o_disconnect      = echo_disconnect,
634         .o_init_export     = echo_init_export,
635         .o_destroy_export  = echo_destroy_export,
636         .o_create          = echo_create,
637         .o_destroy         = echo_destroy,
638         .o_getattr         = echo_getattr,
639         .o_setattr         = echo_setattr,
640         .o_preprw          = echo_preprw,
641         .o_commitrw        = echo_commitrw,
642         .o_setup           = echo_setup,
643         .o_cleanup         = echo_cleanup
644 };
645
646 void echo_persistent_pages_fini(void)
647 {
648         int     i;
649
650         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++)
651                 if (echo_persistent_pages[i] != NULL) {
652                         OBD_PAGE_FREE(echo_persistent_pages[i]);
653                         echo_persistent_pages[i] = NULL;
654                 }
655 }
656
657 int echo_persistent_pages_init(void)
658 {
659         cfs_page_t *pg;
660         int          i;
661
662         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++) {
663                 int gfp_mask = (i < ECHO_PERSISTENT_PAGES/2) ?
664                         CFS_ALLOC_STD : CFS_ALLOC_HIGHUSER;
665
666                 OBD_PAGE_ALLOC(pg, gfp_mask);
667                 if (pg == NULL) {
668                         echo_persistent_pages_fini ();
669                         return (-ENOMEM);
670                 }
671
672                 memset (cfs_kmap (pg), 0, CFS_PAGE_SIZE);
673                 cfs_kunmap (pg);
674
675                 echo_persistent_pages[i] = pg;
676         }
677
678         return (0);
679 }