5293bc411d17735fcfed8b685e7d3ab9d0e80da4
[linux-flexiantxendom0-natty.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 <scsi/scsi_device.h>
26 #include <asm/div64.h>
27
28 #include "exofs.h"
29
30 #define EXOFS_DBGMSG2(M...) do {} while (0)
31 /* #define EXOFS_DBGMSG2 EXOFS_DBGMSG */
32
33 void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
34 {
35         osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
36 }
37
38 int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
39                     u64 offset, void *p, unsigned length)
40 {
41         struct osd_request *or = osd_start_request(od, GFP_KERNEL);
42 /*      struct osd_sense_info osi = {.key = 0};*/
43         int ret;
44
45         if (unlikely(!or)) {
46                 EXOFS_DBGMSG("%s: osd_start_request failed.\n", __func__);
47                 return -ENOMEM;
48         }
49         ret = osd_req_read_kern(or, obj, offset, p, length);
50         if (unlikely(ret)) {
51                 EXOFS_DBGMSG("%s: osd_req_read_kern failed.\n", __func__);
52                 goto out;
53         }
54
55         ret = osd_finalize_request(or, 0, cred, NULL);
56         if (unlikely(ret)) {
57                 EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n", ret);
58                 goto out;
59         }
60
61         ret = osd_execute_request(or);
62         if (unlikely(ret))
63                 EXOFS_DBGMSG("osd_execute_request() => %d\n", ret);
64         /* osd_req_decode_sense(or, ret); */
65
66 out:
67         osd_end_request(or);
68         return ret;
69 }
70
71 int exofs_get_io_state(struct exofs_layout *layout,
72                        struct exofs_io_state **pios)
73 {
74         struct exofs_io_state *ios;
75
76         /*TODO: Maybe use kmem_cach per sbi of size
77          * exofs_io_state_size(layout->s_numdevs)
78          */
79         ios = kzalloc(exofs_io_state_size(layout->s_numdevs), GFP_KERNEL);
80         if (unlikely(!ios)) {
81                 EXOFS_DBGMSG("Faild kzalloc bytes=%d\n",
82                              exofs_io_state_size(layout->s_numdevs));
83                 *pios = NULL;
84                 return -ENOMEM;
85         }
86
87         ios->layout = layout;
88         ios->obj.partition = layout->s_pid;
89         *pios = ios;
90         return 0;
91 }
92
93 void exofs_put_io_state(struct exofs_io_state *ios)
94 {
95         if (ios) {
96                 unsigned i;
97
98                 for (i = 0; i < ios->numdevs; i++) {
99                         struct exofs_per_dev_state *per_dev = &ios->per_dev[i];
100
101                         if (per_dev->or)
102                                 osd_end_request(per_dev->or);
103                         if (per_dev->bio)
104                                 bio_put(per_dev->bio);
105                 }
106
107                 kfree(ios);
108         }
109 }
110
111 unsigned exofs_layout_od_id(struct exofs_layout *layout,
112                             osd_id obj_no, unsigned layout_index)
113 {
114 /*      switch (layout->lay_func) {
115         case LAYOUT_MOVING_WINDOW:
116         {*/
117                 unsigned dev_mod = obj_no;
118
119                 return (layout_index + dev_mod * layout->mirrors_p1) %
120                                                               layout->s_numdevs;
121 /*      }
122         case LAYOUT_FUNC_IMPLICT:
123                 return layout->devs[layout_index];
124         }*/
125 }
126
127 static inline struct osd_dev *exofs_ios_od(struct exofs_io_state *ios,
128                                            unsigned layout_index)
129 {
130         return ios->layout->s_ods[
131                 exofs_layout_od_id(ios->layout, ios->obj.id, layout_index)];
132 }
133
134 static void _sync_done(struct exofs_io_state *ios, void *p)
135 {
136         struct completion *waiting = p;
137
138         complete(waiting);
139 }
140
141 static void _last_io(struct kref *kref)
142 {
143         struct exofs_io_state *ios = container_of(
144                                         kref, struct exofs_io_state, kref);
145
146         ios->done(ios, ios->private);
147 }
148
149 static void _done_io(struct osd_request *or, void *p)
150 {
151         struct exofs_io_state *ios = p;
152
153         kref_put(&ios->kref, _last_io);
154 }
155
156 static int exofs_io_execute(struct exofs_io_state *ios)
157 {
158         DECLARE_COMPLETION_ONSTACK(wait);
159         bool sync = (ios->done == NULL);
160         int i, ret;
161
162         if (sync) {
163                 ios->done = _sync_done;
164                 ios->private = &wait;
165         }
166
167         for (i = 0; i < ios->numdevs; i++) {
168                 struct osd_request *or = ios->per_dev[i].or;
169                 if (unlikely(!or))
170                         continue;
171
172                 ret = osd_finalize_request(or, 0, ios->cred, NULL);
173                 if (unlikely(ret)) {
174                         EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n",
175                                      ret);
176                         return ret;
177                 }
178         }
179
180         kref_init(&ios->kref);
181
182         for (i = 0; i < ios->numdevs; i++) {
183                 struct osd_request *or = ios->per_dev[i].or;
184                 if (unlikely(!or))
185                         continue;
186
187                 kref_get(&ios->kref);
188                 osd_execute_request_async(or, _done_io, ios);
189         }
190
191         kref_put(&ios->kref, _last_io);
192         ret = 0;
193
194         if (sync) {
195                 wait_for_completion(&wait);
196                 ret = exofs_check_io(ios, NULL);
197         }
198         return ret;
199 }
200
201 static void _clear_bio(struct bio *bio)
202 {
203         struct bio_vec *bv;
204         unsigned i;
205
206         __bio_for_each_segment(bv, bio, i, 0) {
207                 unsigned this_count = bv->bv_len;
208
209                 if (likely(PAGE_SIZE == this_count))
210                         clear_highpage(bv->bv_page);
211                 else
212                         zero_user(bv->bv_page, bv->bv_offset, this_count);
213         }
214 }
215
216 int exofs_check_io(struct exofs_io_state *ios, u64 *resid)
217 {
218         enum osd_err_priority acumulated_osd_err = 0;
219         int acumulated_lin_err = 0;
220         int i;
221
222         for (i = 0; i < ios->numdevs; i++) {
223                 struct osd_sense_info osi;
224                 struct osd_request *or = ios->per_dev[i].or;
225                 int ret;
226
227                 if (unlikely(!or))
228                         continue;
229
230                 ret = osd_req_decode_sense(or, &osi);
231                 if (likely(!ret))
232                         continue;
233
234                 if (OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) {
235                         /* start read offset passed endof file */
236                         _clear_bio(ios->per_dev[i].bio);
237                         EXOFS_DBGMSG("start read offset passed end of file "
238                                 "offset=0x%llx, length=0x%llx\n",
239                                 _LLU(ios->per_dev[i].offset),
240                                 _LLU(ios->per_dev[i].length));
241
242                         continue; /* we recovered */
243                 }
244
245                 if (osi.osd_err_pri >= acumulated_osd_err) {
246                         acumulated_osd_err = osi.osd_err_pri;
247                         acumulated_lin_err = ret;
248                 }
249         }
250
251         /* TODO: raid specific residual calculations */
252         if (resid) {
253                 if (likely(!acumulated_lin_err))
254                         *resid = 0;
255                 else
256                         *resid = ios->length;
257         }
258
259         return acumulated_lin_err;
260 }
261
262 /*
263  * L - logical offset into the file
264  *
265  * U - The number of bytes in a stripe within a group
266  *
267  *      U = stripe_unit * group_width
268  *
269  * T - The number of bytes striped within a group of component objects
270  *     (before advancing to the next group)
271  *
272  *      T = stripe_unit * group_width * group_depth
273  *
274  * S - The number of bytes striped across all component objects
275  *     before the pattern repeats
276  *
277  *      S = stripe_unit * group_width * group_depth * group_count
278  *
279  * M - The "major" (i.e., across all components) stripe number
280  *
281  *      M = L / S
282  *
283  * G - Counts the groups from the beginning of the major stripe
284  *
285  *      G = (L - (M * S)) / T   [or (L % S) / T]
286  *
287  * H - The byte offset within the group
288  *
289  *      H = (L - (M * S)) % T   [or (L % S) % T]
290  *
291  * N - The "minor" (i.e., across the group) stripe number
292  *
293  *      N = H / U
294  *
295  * C - The component index coresponding to L
296  *
297  *      C = (H - (N * U)) / stripe_unit + G * group_width
298  *      [or (L % U) / stripe_unit + G * group_width]
299  *
300  * O - The component offset coresponding to L
301  *
302  *      O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
303  */
304 struct _striping_info {
305         u64 obj_offset;
306         u64 group_length;
307         u64 total_group_length;
308         u64 Major;
309         unsigned dev;
310         unsigned unit_off;
311 };
312
313 static void _calc_stripe_info(struct exofs_io_state *ios, u64 file_offset,
314                               struct _striping_info *si)
315 {
316         u32     stripe_unit = ios->layout->stripe_unit;
317         u32     group_width = ios->layout->group_width;
318         u64     group_depth = ios->layout->group_depth;
319
320         u32     U = stripe_unit * group_width;
321         u64     T = U * group_depth;
322         u64     S = T * ios->layout->group_count;
323         u64     M = div64_u64(file_offset, S);
324
325         /*
326         G = (L - (M * S)) / T
327         H = (L - (M * S)) % T
328         */
329         u64     LmodS = file_offset - M * S;
330         u32     G = div64_u64(LmodS, T);
331         u64     H = LmodS - G * T;
332
333         u32     N = div_u64(H, U);
334
335         /* "H - (N * U)" is just "H % U" so it's bound to u32 */
336         si->dev = (u32)(H - (N * U)) / stripe_unit + G * group_width;
337         si->dev *= ios->layout->mirrors_p1;
338
339         div_u64_rem(file_offset, stripe_unit, &si->unit_off);
340
341         si->obj_offset = si->unit_off + (N * stripe_unit) +
342                                   (M * group_depth * stripe_unit);
343
344         si->group_length = T - H;
345         si->total_group_length = T;
346         si->Major = M;
347 }
348
349 static int _add_stripe_unit(struct exofs_io_state *ios,  unsigned *cur_pg,
350                 unsigned pgbase, struct exofs_per_dev_state *per_dev,
351                 int cur_len)
352 {
353         unsigned pg = *cur_pg;
354         struct request_queue *q =
355                         osd_request_queue(exofs_ios_od(ios, per_dev->dev));
356
357         per_dev->length += cur_len;
358
359         if (per_dev->bio == NULL) {
360                 unsigned pages_in_stripe = ios->layout->group_width *
361                                         (ios->layout->stripe_unit / PAGE_SIZE);
362                 unsigned bio_size = (ios->nr_pages + pages_in_stripe) /
363                                                 ios->layout->group_width;
364
365                 per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
366                 if (unlikely(!per_dev->bio)) {
367                         EXOFS_DBGMSG("Faild to allocate BIO size=%u\n",
368                                      bio_size);
369                         return -ENOMEM;
370                 }
371         }
372
373         while (cur_len > 0) {
374                 unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
375                 unsigned added_len;
376
377                 BUG_ON(ios->nr_pages <= pg);
378                 cur_len -= pglen;
379
380                 added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
381                                             pglen, pgbase);
382                 if (unlikely(pglen != added_len))
383                         return -ENOMEM;
384                 pgbase = 0;
385                 ++pg;
386         }
387         BUG_ON(cur_len);
388
389         *cur_pg = pg;
390         return 0;
391 }
392
393 static int _prepare_one_group(struct exofs_io_state *ios, u64 length,
394                               struct _striping_info *si, unsigned first_comp)
395 {
396         unsigned stripe_unit = ios->layout->stripe_unit;
397         unsigned mirrors_p1 = ios->layout->mirrors_p1;
398         unsigned devs_in_group = ios->layout->group_width * mirrors_p1;
399         unsigned dev = si->dev;
400         unsigned first_dev = dev - (dev % devs_in_group);
401         unsigned comp = first_comp + (dev - first_dev);
402         unsigned max_comp = ios->numdevs ? ios->numdevs - mirrors_p1 : 0;
403         unsigned cur_pg = ios->pages_consumed;
404         int ret = 0;
405
406         while (length) {
407                 struct exofs_per_dev_state *per_dev = &ios->per_dev[comp];
408                 unsigned cur_len, page_off = 0;
409
410                 if (!per_dev->length) {
411                         per_dev->dev = dev;
412                         if (dev < si->dev) {
413                                 per_dev->offset = si->obj_offset + stripe_unit -
414                                                                    si->unit_off;
415                                 cur_len = stripe_unit;
416                         } else if (dev == si->dev) {
417                                 per_dev->offset = si->obj_offset;
418                                 cur_len = stripe_unit - si->unit_off;
419                                 page_off = si->unit_off & ~PAGE_MASK;
420                                 BUG_ON(page_off && (page_off != ios->pgbase));
421                         } else { /* dev > si->dev */
422                                 per_dev->offset = si->obj_offset - si->unit_off;
423                                 cur_len = stripe_unit;
424                         }
425
426                         if (max_comp < comp)
427                                 max_comp = comp;
428
429                         dev += mirrors_p1;
430                         dev = (dev % devs_in_group) + first_dev;
431                 } else {
432                         cur_len = stripe_unit;
433                 }
434                 if (cur_len >= length)
435                         cur_len = length;
436
437                 ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
438                                        cur_len);
439                 if (unlikely(ret))
440                         goto out;
441
442                 comp += mirrors_p1;
443                 comp = (comp % devs_in_group) + first_comp;
444
445                 length -= cur_len;
446         }
447 out:
448         ios->numdevs = max_comp + mirrors_p1;
449         ios->pages_consumed = cur_pg;
450         return ret;
451 }
452
453 static int _prepare_for_striping(struct exofs_io_state *ios)
454 {
455         u64 length = ios->length;
456         struct _striping_info si;
457         unsigned devs_in_group = ios->layout->group_width *
458                                  ios->layout->mirrors_p1;
459         unsigned first_comp = 0;
460         int ret = 0;
461
462         _calc_stripe_info(ios, ios->offset, &si);
463
464         if (!ios->pages) {
465                 if (ios->kern_buff) {
466                         struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
467
468                         per_dev->offset = si.obj_offset;
469                         per_dev->dev = si.dev;
470
471                         /* no cross device without page array */
472                         BUG_ON((ios->layout->group_width > 1) &&
473                                (si.unit_off + ios->length >
474                                 ios->layout->stripe_unit));
475                 }
476                 ios->numdevs = ios->layout->mirrors_p1;
477                 return 0;
478         }
479
480         while (length) {
481                 if (length < si.group_length)
482                         si.group_length = length;
483
484                 ret = _prepare_one_group(ios, si.group_length, &si, first_comp);
485                 if (unlikely(ret))
486                         goto out;
487
488                 length -= si.group_length;
489
490                 si.group_length = si.total_group_length;
491                 si.unit_off = 0;
492                 ++si.Major;
493                 si.obj_offset = si.Major * ios->layout->stripe_unit *
494                                                 ios->layout->group_depth;
495
496                 si.dev = (si.dev - (si.dev % devs_in_group)) + devs_in_group;
497                 si.dev %= ios->layout->s_numdevs;
498
499                 first_comp += devs_in_group;
500                 first_comp %= ios->layout->s_numdevs;
501         }
502
503 out:
504         return ret;
505 }
506
507 int exofs_sbi_create(struct exofs_io_state *ios)
508 {
509         int i, ret;
510
511         for (i = 0; i < ios->layout->s_numdevs; i++) {
512                 struct osd_request *or;
513
514                 or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL);
515                 if (unlikely(!or)) {
516                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
517                         ret = -ENOMEM;
518                         goto out;
519                 }
520                 ios->per_dev[i].or = or;
521                 ios->numdevs++;
522
523                 osd_req_create_object(or, &ios->obj);
524         }
525         ret = exofs_io_execute(ios);
526
527 out:
528         return ret;
529 }
530
531 int exofs_sbi_remove(struct exofs_io_state *ios)
532 {
533         int i, ret;
534
535         for (i = 0; i < ios->layout->s_numdevs; i++) {
536                 struct osd_request *or;
537
538                 or = osd_start_request(exofs_ios_od(ios, i), GFP_KERNEL);
539                 if (unlikely(!or)) {
540                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
541                         ret = -ENOMEM;
542                         goto out;
543                 }
544                 ios->per_dev[i].or = or;
545                 ios->numdevs++;
546
547                 osd_req_remove_object(or, &ios->obj);
548         }
549         ret = exofs_io_execute(ios);
550
551 out:
552         return ret;
553 }
554
555 static int _sbi_write_mirror(struct exofs_io_state *ios, int cur_comp)
556 {
557         struct exofs_per_dev_state *master_dev = &ios->per_dev[cur_comp];
558         unsigned dev = ios->per_dev[cur_comp].dev;
559         unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
560         int ret = 0;
561
562         if (ios->pages && !master_dev->length)
563                 return 0; /* Just an empty slot */
564
565         for (; cur_comp < last_comp; ++cur_comp, ++dev) {
566                 struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
567                 struct osd_request *or;
568
569                 or = osd_start_request(exofs_ios_od(ios, dev), GFP_KERNEL);
570                 if (unlikely(!or)) {
571                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
572                         ret = -ENOMEM;
573                         goto out;
574                 }
575                 per_dev->or = or;
576                 per_dev->offset = master_dev->offset;
577
578                 if (ios->pages) {
579                         struct bio *bio;
580
581                         if (per_dev != master_dev) {
582                                 bio = bio_kmalloc(GFP_KERNEL,
583                                                   master_dev->bio->bi_max_vecs);
584                                 if (unlikely(!bio)) {
585                                         EXOFS_DBGMSG(
586                                               "Faild to allocate BIO size=%u\n",
587                                               master_dev->bio->bi_max_vecs);
588                                         ret = -ENOMEM;
589                                         goto out;
590                                 }
591
592                                 __bio_clone(bio, master_dev->bio);
593                                 bio->bi_bdev = NULL;
594                                 bio->bi_next = NULL;
595                                 per_dev->length = master_dev->length;
596                                 per_dev->bio =  bio;
597                                 per_dev->dev = dev;
598                         } else {
599                                 bio = master_dev->bio;
600                                 /* FIXME: bio_set_dir() */
601                                 bio->bi_rw |= (1 << BIO_RW);
602                         }
603
604                         osd_req_write(or, &ios->obj, per_dev->offset, bio,
605                                       per_dev->length);
606                         EXOFS_DBGMSG("write(0x%llx) offset=0x%llx "
607                                       "length=0x%llx dev=%d\n",
608                                      _LLU(ios->obj.id), _LLU(per_dev->offset),
609                                      _LLU(per_dev->length), dev);
610                 } else if (ios->kern_buff) {
611                         ret = osd_req_write_kern(or, &ios->obj, per_dev->offset,
612                                            ios->kern_buff, ios->length);
613                         if (unlikely(ret))
614                                 goto out;
615                         EXOFS_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
616                                       "length=0x%llx dev=%d\n",
617                                      _LLU(ios->obj.id), _LLU(per_dev->offset),
618                                      _LLU(ios->length), dev);
619                 } else {
620                         osd_req_set_attributes(or, &ios->obj);
621                         EXOFS_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
622                                      _LLU(ios->obj.id), ios->out_attr_len, dev);
623                 }
624
625                 if (ios->out_attr)
626                         osd_req_add_set_attr_list(or, ios->out_attr,
627                                                   ios->out_attr_len);
628
629                 if (ios->in_attr)
630                         osd_req_add_get_attr_list(or, ios->in_attr,
631                                                   ios->in_attr_len);
632         }
633
634 out:
635         return ret;
636 }
637
638 int exofs_sbi_write(struct exofs_io_state *ios)
639 {
640         int i;
641         int ret;
642
643         ret = _prepare_for_striping(ios);
644         if (unlikely(ret))
645                 return ret;
646
647         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
648                 ret = _sbi_write_mirror(ios, i);
649                 if (unlikely(ret))
650                         return ret;
651         }
652
653         ret = exofs_io_execute(ios);
654         return ret;
655 }
656
657 static int _sbi_read_mirror(struct exofs_io_state *ios, unsigned cur_comp)
658 {
659         struct osd_request *or;
660         struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
661         unsigned first_dev = (unsigned)ios->obj.id;
662
663         if (ios->pages && !per_dev->length)
664                 return 0; /* Just an empty slot */
665
666         first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
667         or = osd_start_request(exofs_ios_od(ios, first_dev), GFP_KERNEL);
668         if (unlikely(!or)) {
669                 EXOFS_ERR("%s: osd_start_request failed\n", __func__);
670                 return -ENOMEM;
671         }
672         per_dev->or = or;
673
674         if (ios->pages) {
675                 osd_req_read(or, &ios->obj, per_dev->offset,
676                                 per_dev->bio, per_dev->length);
677                 EXOFS_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
678                              " dev=%d\n", _LLU(ios->obj.id),
679                              _LLU(per_dev->offset), _LLU(per_dev->length),
680                              first_dev);
681         } else if (ios->kern_buff) {
682                 int ret = osd_req_read_kern(or, &ios->obj, per_dev->offset,
683                                             ios->kern_buff, ios->length);
684                 EXOFS_DBGMSG2("read_kern(0x%llx) offset=0x%llx "
685                               "length=0x%llx dev=%d ret=>%d\n",
686                               _LLU(ios->obj.id), _LLU(per_dev->offset),
687                               _LLU(ios->length), first_dev, ret);
688                 if (unlikely(ret))
689                         return ret;
690         } else {
691                 osd_req_get_attributes(or, &ios->obj);
692                 EXOFS_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
693                               _LLU(ios->obj.id), ios->in_attr_len, first_dev);
694         }
695         if (ios->out_attr)
696                 osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);
697
698         if (ios->in_attr)
699                 osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);
700
701         return 0;
702 }
703
704 int exofs_sbi_read(struct exofs_io_state *ios)
705 {
706         int i;
707         int ret;
708
709         ret = _prepare_for_striping(ios);
710         if (unlikely(ret))
711                 return ret;
712
713         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
714                 ret = _sbi_read_mirror(ios, i);
715                 if (unlikely(ret))
716                         return ret;
717         }
718
719         ret = exofs_io_execute(ios);
720         return ret;
721 }
722
723 int extract_attr_from_ios(struct exofs_io_state *ios, struct osd_attr *attr)
724 {
725         struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
726         void *iter = NULL;
727         int nelem;
728
729         do {
730                 nelem = 1;
731                 osd_req_decode_get_attr_list(ios->per_dev[0].or,
732                                              &cur_attr, &nelem, &iter);
733                 if ((cur_attr.attr_page == attr->attr_page) &&
734                     (cur_attr.attr_id == attr->attr_id)) {
735                         attr->len = cur_attr.len;
736                         attr->val_ptr = cur_attr.val_ptr;
737                         return 0;
738                 }
739         } while (iter);
740
741         return -EIO;
742 }
743
744 static int _truncate_mirrors(struct exofs_io_state *ios, unsigned cur_comp,
745                              struct osd_attr *attr)
746 {
747         int last_comp = cur_comp + ios->layout->mirrors_p1;
748
749         for (; cur_comp < last_comp; ++cur_comp) {
750                 struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
751                 struct osd_request *or;
752
753                 or = osd_start_request(exofs_ios_od(ios, cur_comp), GFP_KERNEL);
754                 if (unlikely(!or)) {
755                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
756                         return -ENOMEM;
757                 }
758                 per_dev->or = or;
759
760                 osd_req_set_attributes(or, &ios->obj);
761                 osd_req_add_set_attr_list(or, attr, 1);
762         }
763
764         return 0;
765 }
766
767 int exofs_oi_truncate(struct exofs_i_info *oi, u64 size)
768 {
769         struct exofs_sb_info *sbi = oi->vfs_inode.i_sb->s_fs_info;
770         struct exofs_io_state *ios;
771         struct exofs_trunc_attr {
772                 struct osd_attr attr;
773                 __be64 newsize;
774         } *size_attrs;
775         struct _striping_info si;
776         int i, ret;
777
778         ret = exofs_get_io_state(&sbi->layout, &ios);
779         if (unlikely(ret))
780                 return ret;
781
782         size_attrs = kcalloc(ios->layout->group_width, sizeof(*size_attrs),
783                              GFP_KERNEL);
784         if (unlikely(!size_attrs)) {
785                 ret = -ENOMEM;
786                 goto out;
787         }
788
789         ios->obj.id = exofs_oi_objno(oi);
790         ios->cred = oi->i_cred;
791
792         ios->numdevs = ios->layout->s_numdevs;
793         _calc_stripe_info(ios, size, &si);
794
795         for (i = 0; i < ios->layout->group_width; ++i) {
796                 struct exofs_trunc_attr *size_attr = &size_attrs[i];
797                 u64 obj_size;
798
799                 if (i < si.dev)
800                         obj_size = si.obj_offset +
801                                         ios->layout->stripe_unit - si.unit_off;
802                 else if (i == si.dev)
803                         obj_size = si.obj_offset;
804                 else /* i > si.dev */
805                         obj_size = si.obj_offset - si.unit_off;
806
807                 size_attr->newsize = cpu_to_be64(obj_size);
808                 size_attr->attr = g_attr_logical_length;
809                 size_attr->attr.val_ptr = &size_attr->newsize;
810
811                 ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
812                                         &size_attr->attr);
813                 if (unlikely(ret))
814                         goto out;
815         }
816         ret = exofs_io_execute(ios);
817
818 out:
819         kfree(size_attrs);
820         exofs_put_io_state(ios);
821         return ret;
822 }