Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
[linux-2.6.git] / fs / exofs / ios.c
1 /*
2  * Copyright (C) 2005, 2006
3  * Avishay Traeger (avishay@gmail.com)
4  * Copyright (C) 2008, 2009
5  * Boaz Harrosh <bharrosh@panasas.com>
6  *
7  * This file is part of exofs.
8  *
9  * exofs is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation.  Since it is based on ext2, and the only
12  * valid version of GPL for the Linux kernel is version 2, the only valid
13  * version of GPL for exofs is version 2.
14  *
15  * exofs is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with exofs; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
23  */
24
25 #include <linux/slab.h>
26 #include <scsi/scsi_device.h>
27 #include <asm/div64.h>
28
29 #include "exofs.h"
30
31 #define EXOFS_DBGMSG2(M...) do {} while (0)
32 /* #define EXOFS_DBGMSG2 EXOFS_DBGMSG */
33
34 void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
35 {
36         osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
37 }
38
39 int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
40                     u64 offset, void *p, unsigned length)
41 {
42         struct osd_request *or = osd_start_request(od, GFP_KERNEL);
43 /*      struct osd_sense_info osi = {.key = 0};*/
44         int ret;
45
46         if (unlikely(!or)) {
47                 EXOFS_DBGMSG("%s: osd_start_request failed.\n", __func__);
48                 return -ENOMEM;
49         }
50         ret = osd_req_read_kern(or, obj, offset, p, length);
51         if (unlikely(ret)) {
52                 EXOFS_DBGMSG("%s: osd_req_read_kern failed.\n", __func__);
53                 goto out;
54         }
55
56         ret = osd_finalize_request(or, 0, cred, NULL);
57         if (unlikely(ret)) {
58                 EXOFS_DBGMSG("Failed to osd_finalize_request() => %d\n", ret);
59                 goto out;
60         }
61
62         ret = osd_execute_request(or);
63         if (unlikely(ret))
64                 EXOFS_DBGMSG("osd_execute_request() => %d\n", ret);
65         /* osd_req_decode_sense(or, ret); */
66
67 out:
68         osd_end_request(or);
69         return ret;
70 }
71
72 int exofs_get_io_state(struct exofs_layout *layout,
73                        struct exofs_io_state **pios)
74 {
75         struct exofs_io_state *ios;
76
77         /*TODO: Maybe use kmem_cach per sbi of size
78          * exofs_io_state_size(layout->s_numdevs)
79          */
80         ios = kzalloc(exofs_io_state_size(layout->s_numdevs), GFP_KERNEL);
81         if (unlikely(!ios)) {
82                 EXOFS_DBGMSG("Failed kzalloc bytes=%d\n",
83                              exofs_io_state_size(layout->s_numdevs));
84                 *pios = NULL;
85                 return -ENOMEM;
86         }
87
88         ios->layout = layout;
89         ios->obj.partition = layout->s_pid;
90         *pios = ios;
91         return 0;
92 }
93
94 void exofs_put_io_state(struct exofs_io_state *ios)
95 {
96         if (ios) {
97                 unsigned i;
98
99                 for (i = 0; i < ios->numdevs; i++) {
100                         struct exofs_per_dev_state *per_dev = &ios->per_dev[i];
101
102                         if (per_dev->or)
103                                 osd_end_request(per_dev->or);
104                         if (per_dev->bio)
105                                 bio_put(per_dev->bio);
106                 }
107
108                 kfree(ios);
109         }
110 }
111
112 unsigned exofs_layout_od_id(struct exofs_layout *layout,
113                             osd_id obj_no, unsigned layout_index)
114 {
115 /*      switch (layout->lay_func) {
116         case LAYOUT_MOVING_WINDOW:
117         {*/
118                 unsigned dev_mod = obj_no;
119
120                 return (layout_index + dev_mod * layout->mirrors_p1) %
121                                                               layout->s_numdevs;
122 /*      }
123         case LAYOUT_FUNC_IMPLICT:
124                 return layout->devs[layout_index];
125         }*/
126 }
127
128 static inline struct osd_dev *exofs_ios_od(struct exofs_io_state *ios,
129                                            unsigned layout_index)
130 {
131         return ios->layout->s_ods[
132                 exofs_layout_od_id(ios->layout, ios->obj.id, layout_index)];
133 }
134
135 static void _sync_done(struct exofs_io_state *ios, void *p)
136 {
137         struct completion *waiting = p;
138
139         complete(waiting);
140 }
141
142 static void _last_io(struct kref *kref)
143 {
144         struct exofs_io_state *ios = container_of(
145                                         kref, struct exofs_io_state, kref);
146
147         ios->done(ios, ios->private);
148 }
149
150 static void _done_io(struct osd_request *or, void *p)
151 {
152         struct exofs_io_state *ios = p;
153
154         kref_put(&ios->kref, _last_io);
155 }
156
157 static int exofs_io_execute(struct exofs_io_state *ios)
158 {
159         DECLARE_COMPLETION_ONSTACK(wait);
160         bool sync = (ios->done == NULL);
161         int i, ret;
162
163         if (sync) {
164                 ios->done = _sync_done;
165                 ios->private = &wait;
166         }
167
168         for (i = 0; i < ios->numdevs; i++) {
169                 struct osd_request *or = ios->per_dev[i].or;
170                 if (unlikely(!or))
171                         continue;
172
173                 ret = osd_finalize_request(or, 0, ios->cred, NULL);
174                 if (unlikely(ret)) {
175                         EXOFS_DBGMSG("Failed to osd_finalize_request() => %d\n",
176                                      ret);
177                         return ret;
178                 }
179         }
180
181         kref_init(&ios->kref);
182
183         for (i = 0; i < ios->numdevs; i++) {
184                 struct osd_request *or = ios->per_dev[i].or;
185                 if (unlikely(!or))
186                         continue;
187
188                 kref_get(&ios->kref);
189                 osd_execute_request_async(or, _done_io, ios);
190         }
191
192         kref_put(&ios->kref, _last_io);
193         ret = 0;
194
195         if (sync) {
196                 wait_for_completion(&wait);
197                 ret = exofs_check_io(ios, NULL);
198         }
199         return ret;
200 }
201
202 static void _clear_bio(struct bio *bio)
203 {
204         struct bio_vec *bv;
205         unsigned i;
206
207         __bio_for_each_segment(bv, bio, i, 0) {
208                 unsigned this_count = bv->bv_len;
209
210                 if (likely(PAGE_SIZE == this_count))
211                         clear_highpage(bv->bv_page);
212                 else
213                         zero_user(bv->bv_page, bv->bv_offset, this_count);
214         }
215 }
216
217 int exofs_check_io(struct exofs_io_state *ios, u64 *resid)
218 {
219         enum osd_err_priority acumulated_osd_err = 0;
220         int acumulated_lin_err = 0;
221         int i;
222
223         for (i = 0; i < ios->numdevs; i++) {
224                 struct osd_sense_info osi;
225                 struct osd_request *or = ios->per_dev[i].or;
226                 int ret;
227
228                 if (unlikely(!or))
229                         continue;
230
231                 ret = osd_req_decode_sense(or, &osi);
232                 if (likely(!ret))
233                         continue;
234
235                 if (OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) {
236                         /* start read offset passed endof file */
237                         _clear_bio(ios->per_dev[i].bio);
238                         EXOFS_DBGMSG("start read offset passed end of file "
239                                 "offset=0x%llx, length=0x%llx\n",
240                                 _LLU(ios->per_dev[i].offset),
241                                 _LLU(ios->per_dev[i].length));
242
243                         continue; /* we recovered */
244                 }
245
246                 if (osi.osd_err_pri >= acumulated_osd_err) {
247                         acumulated_osd_err = osi.osd_err_pri;
248                         acumulated_lin_err = ret;
249                 }
250         }
251
252         /* TODO: raid specific residual calculations */
253         if (resid) {
254                 if (likely(!acumulated_lin_err))
255                         *resid = 0;
256                 else
257                         *resid = ios->length;
258         }
259
260         return acumulated_lin_err;
261 }
262
263 /*
264  * L - logical offset into the file
265  *
266  * U - The number of bytes in a stripe within a group
267  *
268  *      U = stripe_unit * group_width
269  *
270  * T - The number of bytes striped within a group of component objects
271  *     (before advancing to the next group)
272  *
273  *      T = stripe_unit * group_width * group_depth
274  *
275  * S - The number of bytes striped across all component objects
276  *     before the pattern repeats
277  *
278  *      S = stripe_unit * group_width * group_depth * group_count
279  *
280  * M - The "major" (i.e., across all components) stripe number
281  *
282  *      M = L / S
283  *
284  * G - Counts the groups from the beginning of the major stripe
285  *
286  *      G = (L - (M * S)) / T   [or (L % S) / T]
287  *
288  * H - The byte offset within the group
289  *
290  *      H = (L - (M * S)) % T   [or (L % S) % T]
291  *
292  * N - The "minor" (i.e., across the group) stripe number
293  *
294  *      N = H / U
295  *
296  * C - The component index coresponding to L
297  *
298  *      C = (H - (N * U)) / stripe_unit + G * group_width
299  *      [or (L % U) / stripe_unit + G * group_width]
300  *
301  * O - The component offset coresponding to L
302  *
303  *      O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
304  */
305 struct _striping_info {
306         u64 obj_offset;
307         u64 group_length;
308         unsigned dev;
309         unsigned unit_off;
310 };
311
312 static void _calc_stripe_info(struct exofs_io_state *ios, u64 file_offset,
313                               struct _striping_info *si)
314 {
315         u32     stripe_unit = ios->layout->stripe_unit;
316         u32     group_width = ios->layout->group_width;
317         u64     group_depth = ios->layout->group_depth;
318
319         u32     U = stripe_unit * group_width;
320         u64     T = U * group_depth;
321         u64     S = T * ios->layout->group_count;
322         u64     M = div64_u64(file_offset, S);
323
324         /*
325         G = (L - (M * S)) / T
326         H = (L - (M * S)) % T
327         */
328         u64     LmodS = file_offset - M * S;
329         u32     G = div64_u64(LmodS, T);
330         u64     H = LmodS - G * T;
331
332         u32     N = div_u64(H, U);
333
334         /* "H - (N * U)" is just "H % U" so it's bound to u32 */
335         si->dev = (u32)(H - (N * U)) / stripe_unit + G * group_width;
336         si->dev *= ios->layout->mirrors_p1;
337
338         div_u64_rem(file_offset, stripe_unit, &si->unit_off);
339
340         si->obj_offset = si->unit_off + (N * stripe_unit) +
341                                   (M * group_depth * stripe_unit);
342
343         si->group_length = T - H;
344 }
345
346 static int _add_stripe_unit(struct exofs_io_state *ios,  unsigned *cur_pg,
347                 unsigned pgbase, struct exofs_per_dev_state *per_dev,
348                 int cur_len)
349 {
350         unsigned pg = *cur_pg;
351         struct request_queue *q =
352                         osd_request_queue(exofs_ios_od(ios, per_dev->dev));
353
354         per_dev->length += cur_len;
355
356         if (per_dev->bio == NULL) {
357                 unsigned pages_in_stripe = ios->layout->group_width *
358                                         (ios->layout->stripe_unit / PAGE_SIZE);
359                 unsigned bio_size = (ios->nr_pages + pages_in_stripe) /
360                                                 ios->layout->group_width;
361
362                 per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
363                 if (unlikely(!per_dev->bio)) {
364                         EXOFS_DBGMSG("Failed to allocate BIO size=%u\n",
365                                      bio_size);
366                         return -ENOMEM;
367                 }
368         }
369
370         while (cur_len > 0) {
371                 unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
372                 unsigned added_len;
373
374                 BUG_ON(ios->nr_pages <= pg);
375                 cur_len -= pglen;
376
377                 added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
378                                             pglen, pgbase);
379                 if (unlikely(pglen != added_len))
380                         return -ENOMEM;
381                 pgbase = 0;
382                 ++pg;
383         }
384         BUG_ON(cur_len);
385
386         *cur_pg = pg;
387         return 0;
388 }
389
390 static int _prepare_one_group(struct exofs_io_state *ios, u64 length,
391                               struct _striping_info *si)
392 {
393         unsigned stripe_unit = ios->layout->stripe_unit;
394         unsigned mirrors_p1 = ios->layout->mirrors_p1;
395         unsigned devs_in_group = ios->layout->group_width * mirrors_p1;
396         unsigned dev = si->dev;
397         unsigned first_dev = dev - (dev % devs_in_group);
398         unsigned max_comp = ios->numdevs ? ios->numdevs - mirrors_p1 : 0;
399         unsigned cur_pg = ios->pages_consumed;
400         int ret = 0;
401
402         while (length) {
403                 struct exofs_per_dev_state *per_dev = &ios->per_dev[dev];
404                 unsigned cur_len, page_off = 0;
405
406                 if (!per_dev->length) {
407                         per_dev->dev = dev;
408                         if (dev < si->dev) {
409                                 per_dev->offset = si->obj_offset + stripe_unit -
410                                                                    si->unit_off;
411                                 cur_len = stripe_unit;
412                         } else if (dev == si->dev) {
413                                 per_dev->offset = si->obj_offset;
414                                 cur_len = stripe_unit - si->unit_off;
415                                 page_off = si->unit_off & ~PAGE_MASK;
416                                 BUG_ON(page_off && (page_off != ios->pgbase));
417                         } else { /* dev > si->dev */
418                                 per_dev->offset = si->obj_offset - si->unit_off;
419                                 cur_len = stripe_unit;
420                         }
421
422                         if (max_comp < dev)
423                                 max_comp = dev;
424                 } else {
425                         cur_len = stripe_unit;
426                 }
427                 if (cur_len >= length)
428                         cur_len = length;
429
430                 ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
431                                        cur_len);
432                 if (unlikely(ret))
433                         goto out;
434
435                 dev += mirrors_p1;
436                 dev = (dev % devs_in_group) + first_dev;
437
438                 length -= cur_len;
439         }
440 out:
441         ios->numdevs = max_comp + mirrors_p1;
442         ios->pages_consumed = cur_pg;
443         return ret;
444 }
445
446 static int _prepare_for_striping(struct exofs_io_state *ios)
447 {
448         u64 length = ios->length;
449         u64 offset = ios->offset;
450         struct _striping_info si;
451         int ret = 0;
452
453         if (!ios->pages) {
454                 if (ios->kern_buff) {
455                         struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
456
457                         _calc_stripe_info(ios, ios->offset, &si);
458                         per_dev->offset = si.obj_offset;
459                         per_dev->dev = si.dev;
460
461                         /* no cross device without page array */
462                         BUG_ON((ios->layout->group_width > 1) &&
463                                (si.unit_off + ios->length >
464                                 ios->layout->stripe_unit));
465                 }
466                 ios->numdevs = ios->layout->mirrors_p1;
467                 return 0;
468         }
469
470         while (length) {
471                 _calc_stripe_info(ios, offset, &si);
472
473                 if (length < si.group_length)
474                         si.group_length = length;
475
476                 ret = _prepare_one_group(ios, si.group_length, &si);
477                 if (unlikely(ret))
478                         goto out;
479
480                 offset += si.group_length;
481                 length -= si.group_length;
482         }
483
484 out:
485         return ret;
486 }
487
488 int exofs_sbi_create(struct exofs_io_state *ios)
489 {
490         int i, ret;
491
492         for (i = 0; i < ios->layout->s_numdevs; i++) {
493                 struct osd_request *or;
494
495                 or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL);
496                 if (unlikely(!or)) {
497                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
498                         ret = -ENOMEM;
499                         goto out;
500                 }
501                 ios->per_dev[i].or = or;
502                 ios->numdevs++;
503
504                 osd_req_create_object(or, &ios->obj);
505         }
506         ret = exofs_io_execute(ios);
507
508 out:
509         return ret;
510 }
511
512 int exofs_sbi_remove(struct exofs_io_state *ios)
513 {
514         int i, ret;
515
516         for (i = 0; i < ios->layout->s_numdevs; i++) {
517                 struct osd_request *or;
518
519                 or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL);
520                 if (unlikely(!or)) {
521                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
522                         ret = -ENOMEM;
523                         goto out;
524                 }
525                 ios->per_dev[i].or = or;
526                 ios->numdevs++;
527
528                 osd_req_remove_object(or, &ios->obj);
529         }
530         ret = exofs_io_execute(ios);
531
532 out:
533         return ret;
534 }
535
536 static int _sbi_write_mirror(struct exofs_io_state *ios, int cur_comp)
537 {
538         struct exofs_per_dev_state *master_dev = &ios->per_dev[cur_comp];
539         unsigned dev = ios->per_dev[cur_comp].dev;
540         unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
541         int ret = 0;
542
543         if (ios->pages && !master_dev->length)
544                 return 0; /* Just an empty slot */
545
546         for (; cur_comp < last_comp; ++cur_comp, ++dev) {
547                 struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
548                 struct osd_request *or;
549
550                 or = osd_start_request(exofs_ios_od(ios, dev), GFP_KERNEL);
551                 if (unlikely(!or)) {
552                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
553                         ret = -ENOMEM;
554                         goto out;
555                 }
556                 per_dev->or = or;
557                 per_dev->offset = master_dev->offset;
558
559                 if (ios->pages) {
560                         struct bio *bio;
561
562                         if (per_dev != master_dev) {
563                                 bio = bio_kmalloc(GFP_KERNEL,
564                                                   master_dev->bio->bi_max_vecs);
565                                 if (unlikely(!bio)) {
566                                         EXOFS_DBGMSG(
567                                               "Failed to allocate BIO size=%u\n",
568                                               master_dev->bio->bi_max_vecs);
569                                         ret = -ENOMEM;
570                                         goto out;
571                                 }
572
573                                 __bio_clone(bio, master_dev->bio);
574                                 bio->bi_bdev = NULL;
575                                 bio->bi_next = NULL;
576                                 per_dev->length = master_dev->length;
577                                 per_dev->bio =  bio;
578                                 per_dev->dev = dev;
579                         } else {
580                                 bio = master_dev->bio;
581                                 /* FIXME: bio_set_dir() */
582                                 bio->bi_rw |= REQ_WRITE;
583                         }
584
585                         osd_req_write(or, &ios->obj, per_dev->offset, bio,
586                                       per_dev->length);
587                         EXOFS_DBGMSG("write(0x%llx) offset=0x%llx "
588                                       "length=0x%llx dev=%d\n",
589                                      _LLU(ios->obj.id), _LLU(per_dev->offset),
590                                      _LLU(per_dev->length), dev);
591                 } else if (ios->kern_buff) {
592                         ret = osd_req_write_kern(or, &ios->obj, per_dev->offset,
593                                            ios->kern_buff, ios->length);
594                         if (unlikely(ret))
595                                 goto out;
596                         EXOFS_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
597                                       "length=0x%llx dev=%d\n",
598                                      _LLU(ios->obj.id), _LLU(per_dev->offset),
599                                      _LLU(ios->length), dev);
600                 } else {
601                         osd_req_set_attributes(or, &ios->obj);
602                         EXOFS_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
603                                      _LLU(ios->obj.id), ios->out_attr_len, dev);
604                 }
605
606                 if (ios->out_attr)
607                         osd_req_add_set_attr_list(or, ios->out_attr,
608                                                   ios->out_attr_len);
609
610                 if (ios->in_attr)
611                         osd_req_add_get_attr_list(or, ios->in_attr,
612                                                   ios->in_attr_len);
613         }
614
615 out:
616         return ret;
617 }
618
619 int exofs_sbi_write(struct exofs_io_state *ios)
620 {
621         int i;
622         int ret;
623
624         ret = _prepare_for_striping(ios);
625         if (unlikely(ret))
626                 return ret;
627
628         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
629                 ret = _sbi_write_mirror(ios, i);
630                 if (unlikely(ret))
631                         return ret;
632         }
633
634         ret = exofs_io_execute(ios);
635         return ret;
636 }
637
638 static int _sbi_read_mirror(struct exofs_io_state *ios, unsigned cur_comp)
639 {
640         struct osd_request *or;
641         struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
642         unsigned first_dev = (unsigned)ios->obj.id;
643
644         if (ios->pages && !per_dev->length)
645                 return 0; /* Just an empty slot */
646
647         first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
648         or = osd_start_request(exofs_ios_od(ios, first_dev), GFP_KERNEL);
649         if (unlikely(!or)) {
650                 EXOFS_ERR("%s: osd_start_request failed\n", __func__);
651                 return -ENOMEM;
652         }
653         per_dev->or = or;
654
655         if (ios->pages) {
656                 osd_req_read(or, &ios->obj, per_dev->offset,
657                                 per_dev->bio, per_dev->length);
658                 EXOFS_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
659                              " dev=%d\n", _LLU(ios->obj.id),
660                              _LLU(per_dev->offset), _LLU(per_dev->length),
661                              first_dev);
662         } else if (ios->kern_buff) {
663                 int ret = osd_req_read_kern(or, &ios->obj, per_dev->offset,
664                                             ios->kern_buff, ios->length);
665                 EXOFS_DBGMSG2("read_kern(0x%llx) offset=0x%llx "
666                               "length=0x%llx dev=%d ret=>%d\n",
667                               _LLU(ios->obj.id), _LLU(per_dev->offset),
668                               _LLU(ios->length), first_dev, ret);
669                 if (unlikely(ret))
670                         return ret;
671         } else {
672                 osd_req_get_attributes(or, &ios->obj);
673                 EXOFS_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
674                               _LLU(ios->obj.id), ios->in_attr_len, first_dev);
675         }
676         if (ios->out_attr)
677                 osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);
678
679         if (ios->in_attr)
680                 osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);
681
682         return 0;
683 }
684
685 int exofs_sbi_read(struct exofs_io_state *ios)
686 {
687         int i;
688         int ret;
689
690         ret = _prepare_for_striping(ios);
691         if (unlikely(ret))
692                 return ret;
693
694         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
695                 ret = _sbi_read_mirror(ios, i);
696                 if (unlikely(ret))
697                         return ret;
698         }
699
700         ret = exofs_io_execute(ios);
701         return ret;
702 }
703
704 int extract_attr_from_ios(struct exofs_io_state *ios, struct osd_attr *attr)
705 {
706         struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
707         void *iter = NULL;
708         int nelem;
709
710         do {
711                 nelem = 1;
712                 osd_req_decode_get_attr_list(ios->per_dev[0].or,
713                                              &cur_attr, &nelem, &iter);
714                 if ((cur_attr.attr_page == attr->attr_page) &&
715                     (cur_attr.attr_id == attr->attr_id)) {
716                         attr->len = cur_attr.len;
717                         attr->val_ptr = cur_attr.val_ptr;
718                         return 0;
719                 }
720         } while (iter);
721
722         return -EIO;
723 }
724
725 static int _truncate_mirrors(struct exofs_io_state *ios, unsigned cur_comp,
726                              struct osd_attr *attr)
727 {
728         int last_comp = cur_comp + ios->layout->mirrors_p1;
729
730         for (; cur_comp < last_comp; ++cur_comp) {
731                 struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
732                 struct osd_request *or;
733
734                 or = osd_start_request(exofs_ios_od(ios, cur_comp), GFP_KERNEL);
735                 if (unlikely(!or)) {
736                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
737                         return -ENOMEM;
738                 }
739                 per_dev->or = or;
740
741                 osd_req_set_attributes(or, &ios->obj);
742                 osd_req_add_set_attr_list(or, attr, 1);
743         }
744
745         return 0;
746 }
747
748 int exofs_oi_truncate(struct exofs_i_info *oi, u64 size)
749 {
750         struct exofs_sb_info *sbi = oi->vfs_inode.i_sb->s_fs_info;
751         struct exofs_io_state *ios;
752         struct exofs_trunc_attr {
753                 struct osd_attr attr;
754                 __be64 newsize;
755         } *size_attrs;
756         struct _striping_info si;
757         int i, ret;
758
759         ret = exofs_get_io_state(&sbi->layout, &ios);
760         if (unlikely(ret))
761                 return ret;
762
763         size_attrs = kcalloc(ios->layout->group_width, sizeof(*size_attrs),
764                              GFP_KERNEL);
765         if (unlikely(!size_attrs)) {
766                 ret = -ENOMEM;
767                 goto out;
768         }
769
770         ios->obj.id = exofs_oi_objno(oi);
771         ios->cred = oi->i_cred;
772
773         ios->numdevs = ios->layout->s_numdevs;
774         _calc_stripe_info(ios, size, &si);
775
776         for (i = 0; i < ios->layout->group_width; ++i) {
777                 struct exofs_trunc_attr *size_attr = &size_attrs[i];
778                 u64 obj_size;
779
780                 if (i < si.dev)
781                         obj_size = si.obj_offset +
782                                         ios->layout->stripe_unit - si.unit_off;
783                 else if (i == si.dev)
784                         obj_size = si.obj_offset;
785                 else /* i > si.dev */
786                         obj_size = si.obj_offset - si.unit_off;
787
788                 size_attr->newsize = cpu_to_be64(obj_size);
789                 size_attr->attr = g_attr_logical_length;
790                 size_attr->attr.val_ptr = &size_attr->newsize;
791
792                 ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
793                                         &size_attr->attr);
794                 if (unlikely(ret))
795                         goto out;
796         }
797         ret = exofs_io_execute(ios);
798
799 out:
800         kfree(size_attrs);
801         exofs_put_io_state(ios);
802         return ret;
803 }