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