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 static u8 *_ios_cred(struct exofs_io_state *ios, unsigned index)
  35 {
  36         return ios->comps->comps[index & ios->comps->single_comp].cred;
  37 }
  38
  39 static struct osd_obj_id *_ios_obj(struct exofs_io_state *ios, unsigned index)
  40 {
  41         return &ios->comps->comps[index & ios->comps->single_comp].obj;
  42 }
  43
  44 static struct osd_dev *_ios_od(struct exofs_io_state *ios, unsigned index)
  45 {
  46         return ios->comps->ods[index];
  47 }
  48
  49 int exofs_get_rw_state(struct exofs_layout *layout,
  50                         struct exofs_components *comps,
  51                         bool is_reading, u64 offset, u64 length,
  52                         struct exofs_io_state **pios)
  53 {
  54         struct exofs_io_state *ios;
  55
  56         /*TODO: Maybe use kmem_cach per sbi of size
  57          * exofs_io_state_size(layout->s_numdevs)
  58          */
  59         ios = kzalloc(exofs_io_state_size(comps->numdevs), GFP_KERNEL);
  60         if (unlikely(!ios)) {
  61                 EXOFS_DBGMSG("Failed kzalloc bytes=%d\n",
  62                              exofs_io_state_size(comps->numdevs));
  63                 *pios = NULL;
  64                 return -ENOMEM;
  65         }
  66
  67         ios->layout = layout;
  68         ios->comps = comps;
  69         ios->offset = offset;
  70         ios->length = length;
  71         ios->reading = is_reading;
  72
  73         *pios = ios;
  74         return 0;
  75 }
  76
  77 int  exofs_get_io_state(struct exofs_layout *layout,
  78                         struct exofs_components *comps,
  79                         struct exofs_io_state **ios)
  80 {
  81         return exofs_get_rw_state(layout, comps, true, 0, 0, ios);
  82 }
  83
  84 void exofs_put_io_state(struct exofs_io_state *ios)
  85 {
  86         if (ios) {
  87                 unsigned i;
  88
  89                 for (i = 0; i < ios->numdevs; i++) {
  90                         struct exofs_per_dev_state *per_dev = &ios->per_dev[i];
  91
  92                         if (per_dev->or)
  93                                 osd_end_request(per_dev->or);
  94                         if (per_dev->bio)
  95                                 bio_put(per_dev->bio);
  96                 }
  97
  98                 kfree(ios);
  99         }
 100 }
 101
 102 static void _sync_done(struct exofs_io_state *ios, void *p)
 103 {
 104         struct completion *waiting = p;
 105
 106         complete(waiting);
 107 }
 108
 109 static void _last_io(struct kref *kref)
 110 {
 111         struct exofs_io_state *ios = container_of(
 112                                         kref, struct exofs_io_state, kref);
 113
 114         ios->done(ios, ios->private);
 115 }
 116
 117 static void _done_io(struct osd_request *or, void *p)
 118 {
 119         struct exofs_io_state *ios = p;
 120
 121         kref_put(&ios->kref, _last_io);
 122 }
 123
 124 static int exofs_io_execute(struct exofs_io_state *ios)
 125 {
 126         DECLARE_COMPLETION_ONSTACK(wait);
 127         bool sync = (ios->done == NULL);
 128         int i, ret;
 129
 130         if (sync) {
 131                 ios->done = _sync_done;
 132                 ios->private = &wait;
 133         }
 134
 135         for (i = 0; i < ios->numdevs; i++) {
 136                 struct osd_request *or = ios->per_dev[i].or;
 137                 if (unlikely(!or))
 138                         continue;
 139
 140                 ret = osd_finalize_request(or, 0, _ios_cred(ios, i), NULL);
 141                 if (unlikely(ret)) {
 142                         EXOFS_DBGMSG("Failed to osd_finalize_request() => %d\n",
 143                                      ret);
 144                         return ret;
 145                 }
 146         }
 147
 148         kref_init(&ios->kref);
 149
 150         for (i = 0; i < ios->numdevs; i++) {
 151                 struct osd_request *or = ios->per_dev[i].or;
 152                 if (unlikely(!or))
 153                         continue;
 154
 155                 kref_get(&ios->kref);
 156                 osd_execute_request_async(or, _done_io, ios);
 157         }
 158
 159         kref_put(&ios->kref, _last_io);
 160         ret = 0;
 161
 162         if (sync) {
 163                 wait_for_completion(&wait);
 164                 ret = exofs_check_io(ios, NULL);
 165         }
 166         return ret;
 167 }
 168
 169 static void _clear_bio(struct bio *bio)
 170 {
 171         struct bio_vec *bv;
 172         unsigned i;
 173
 174         __bio_for_each_segment(bv, bio, i, 0) {
 175                 unsigned this_count = bv->bv_len;
 176
 177                 if (likely(PAGE_SIZE == this_count))
 178                         clear_highpage(bv->bv_page);
 179                 else
 180                         zero_user(bv->bv_page, bv->bv_offset, this_count);
 181         }
 182 }
 183
 184 int exofs_check_io(struct exofs_io_state *ios, u64 *resid)
 185 {
 186         enum osd_err_priority acumulated_osd_err = 0;
 187         int acumulated_lin_err = 0;
 188         int i;
 189
 190         for (i = 0; i < ios->numdevs; i++) {
 191                 struct osd_sense_info osi;
 192                 struct osd_request *or = ios->per_dev[i].or;
 193                 int ret;
 194
 195                 if (unlikely(!or))
 196                         continue;
 197
 198                 ret = osd_req_decode_sense(or, &osi);
 199                 if (likely(!ret))
 200                         continue;
 201
 202                 if (OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) {
 203                         /* start read offset passed endof file */
 204                         _clear_bio(ios->per_dev[i].bio);
 205                         EXOFS_DBGMSG("start read offset passed end of file "
 206                                 "offset=0x%llx, length=0x%llx\n",
 207                                 _LLU(ios->per_dev[i].offset),
 208                                 _LLU(ios->per_dev[i].length));
 209
 210                         continue; /* we recovered */
 211                 }
 212
 213                 if (osi.osd_err_pri >= acumulated_osd_err) {
 214                         acumulated_osd_err = osi.osd_err_pri;
 215                         acumulated_lin_err = ret;
 216                 }
 217         }
 218
 219         /* TODO: raid specific residual calculations */
 220         if (resid) {
 221                 if (likely(!acumulated_lin_err))
 222                         *resid = 0;
 223                 else
 224                         *resid = ios->length;
 225         }
 226
 227         return acumulated_lin_err;
 228 }
 229
 230 /*
 231  * L - logical offset into the file
 232  *
 233  * U - The number of bytes in a stripe within a group
 234  *
 235  *      U = stripe_unit * group_width
 236  *
 237  * T - The number of bytes striped within a group of component objects
 238  *     (before advancing to the next group)
 239  *
 240  *      T = stripe_unit * group_width * group_depth
 241  *
 242  * S - The number of bytes striped across all component objects
 243  *     before the pattern repeats
 244  *
 245  *      S = stripe_unit * group_width * group_depth * group_count
 246  *
 247  * M - The "major" (i.e., across all components) stripe number
 248  *
 249  *      M = L / S
 250  *
 251  * G - Counts the groups from the beginning of the major stripe
 252  *
 253  *      G = (L - (M * S)) / T   [or (L % S) / T]
 254  *
 255  * H - The byte offset within the group
 256  *
 257  *      H = (L - (M * S)) % T   [or (L % S) % T]
 258  *
 259  * N - The "minor" (i.e., across the group) stripe number
 260  *
 261  *      N = H / U
 262  *
 263  * C - The component index coresponding to L
 264  *
 265  *      C = (H - (N * U)) / stripe_unit + G * group_width
 266  *      [or (L % U) / stripe_unit + G * group_width]
 267  *
 268  * O - The component offset coresponding to L
 269  *
 270  *      O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
 271  */
 272 struct _striping_info {
 273         u64 obj_offset;
 274         u64 group_length;
 275         u64 M; /* for truncate */
 276         unsigned dev;
 277         unsigned unit_off;
 278 };
 279
 280 static void _calc_stripe_info(struct exofs_layout *layout, u64 file_offset,
 281                               struct _striping_info *si)
 282 {
 283         u32     stripe_unit = layout->stripe_unit;
 284         u32     group_width = layout->group_width;
 285         u64     group_depth = layout->group_depth;
 286
 287         u32     U = stripe_unit * group_width;
 288         u64     T = U * group_depth;
 289         u64     S = T * layout->group_count;
 290         u64     M = div64_u64(file_offset, S);
 291
 292         /*
 293         G = (L - (M * S)) / T
 294         H = (L - (M * S)) % T
 295         */
 296         u64     LmodS = file_offset - M * S;
 297         u32     G = div64_u64(LmodS, T);
 298         u64     H = LmodS - G * T;
 299
 300         u32     N = div_u64(H, U);
 301
 302         /* "H - (N * U)" is just "H % U" so it's bound to u32 */
 303         si->dev = (u32)(H - (N * U)) / stripe_unit + G * group_width;
 304         si->dev *= layout->mirrors_p1;
 305
 306         div_u64_rem(file_offset, stripe_unit, &si->unit_off);
 307
 308         si->obj_offset = si->unit_off + (N * stripe_unit) +
 309                                   (M * group_depth * stripe_unit);
 310
 311         si->group_length = T - H;
 312         si->M = M;
 313 }
 314
 315 static int _add_stripe_unit(struct exofs_io_state *ios,  unsigned *cur_pg,
 316                 unsigned pgbase, struct exofs_per_dev_state *per_dev,
 317                 int cur_len)
 318 {
 319         unsigned pg = *cur_pg;
 320         struct request_queue *q =
 321                         osd_request_queue(_ios_od(ios, per_dev->dev));
 322
 323         per_dev->length += cur_len;
 324
 325         if (per_dev->bio == NULL) {
 326                 unsigned pages_in_stripe = ios->layout->group_width *
 327                                         (ios->layout->stripe_unit / PAGE_SIZE);
 328                 unsigned bio_size = (ios->nr_pages + pages_in_stripe) /
 329                                                 ios->layout->group_width;
 330
 331                 per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
 332                 if (unlikely(!per_dev->bio)) {
 333                         EXOFS_DBGMSG("Failed to allocate BIO size=%u\n",
 334                                      bio_size);
 335                         return -ENOMEM;
 336                 }
 337         }
 338
 339         while (cur_len > 0) {
 340                 unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
 341                 unsigned added_len;
 342
 343                 BUG_ON(ios->nr_pages <= pg);
 344                 cur_len -= pglen;
 345
 346                 added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
 347                                             pglen, pgbase);
 348                 if (unlikely(pglen != added_len))
 349                         return -ENOMEM;
 350                 pgbase = 0;
 351                 ++pg;
 352         }
 353         BUG_ON(cur_len);
 354
 355         *cur_pg = pg;
 356         return 0;
 357 }
 358
 359 static int _prepare_one_group(struct exofs_io_state *ios, u64 length,
 360                               struct _striping_info *si)
 361 {
 362         unsigned stripe_unit = ios->layout->stripe_unit;
 363         unsigned mirrors_p1 = ios->layout->mirrors_p1;
 364         unsigned devs_in_group = ios->layout->group_width * mirrors_p1;
 365         unsigned dev = si->dev;
 366         unsigned first_dev = dev - (dev % devs_in_group);
 367         unsigned max_comp = ios->numdevs ? ios->numdevs - mirrors_p1 : 0;
 368         unsigned cur_pg = ios->pages_consumed;
 369         int ret = 0;
 370
 371         while (length) {
 372                 struct exofs_per_dev_state *per_dev = &ios->per_dev[dev];
 373                 unsigned cur_len, page_off = 0;
 374
 375                 if (!per_dev->length) {
 376                         per_dev->dev = dev;
 377                         if (dev < si->dev) {
 378                                 per_dev->offset = si->obj_offset + stripe_unit -
 379                                                                    si->unit_off;
 380                                 cur_len = stripe_unit;
 381                         } else if (dev == si->dev) {
 382                                 per_dev->offset = si->obj_offset;
 383                                 cur_len = stripe_unit - si->unit_off;
 384                                 page_off = si->unit_off & ~PAGE_MASK;
 385                                 BUG_ON(page_off && (page_off != ios->pgbase));
 386                         } else { /* dev > si->dev */
 387                                 per_dev->offset = si->obj_offset - si->unit_off;
 388                                 cur_len = stripe_unit;
 389                         }
 390
 391                         if (max_comp < dev)
 392                                 max_comp = dev;
 393                 } else {
 394                         cur_len = stripe_unit;
 395                 }
 396                 if (cur_len >= length)
 397                         cur_len = length;
 398
 399                 ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
 400                                        cur_len);
 401                 if (unlikely(ret))
 402                         goto out;
 403
 404                 dev += mirrors_p1;
 405                 dev = (dev % devs_in_group) + first_dev;
 406
 407                 length -= cur_len;
 408         }
 409 out:
 410         ios->numdevs = max_comp + mirrors_p1;
 411         ios->pages_consumed = cur_pg;
 412         return ret;
 413 }
 414
 415 static int _prepare_for_striping(struct exofs_io_state *ios)
 416 {
 417         u64 length = ios->length;
 418         u64 offset = ios->offset;
 419         struct _striping_info si;
 420         int ret = 0;
 421
 422         if (!ios->pages) {
 423                 if (ios->kern_buff) {
 424                         struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
 425
 426                         _calc_stripe_info(ios->layout, ios->offset, &si);
 427                         per_dev->offset = si.obj_offset;
 428                         per_dev->dev = si.dev;
 429
 430                         /* no cross device without page array */
 431                         BUG_ON((ios->layout->group_width > 1) &&
 432                                (si.unit_off + ios->length >
 433                                 ios->layout->stripe_unit));
 434                 }
 435                 ios->numdevs = ios->layout->mirrors_p1;
 436                 return 0;
 437         }
 438
 439         while (length) {
 440                 _calc_stripe_info(ios->layout, offset, &si);
 441
 442                 if (length < si.group_length)
 443                         si.group_length = length;
 444
 445                 ret = _prepare_one_group(ios, si.group_length, &si);
 446                 if (unlikely(ret))
 447                         goto out;
 448
 449                 offset += si.group_length;
 450                 length -= si.group_length;
 451         }
 452
 453 out:
 454         return ret;
 455 }
 456
 457 int exofs_sbi_create(struct exofs_io_state *ios)
 458 {
 459         int i, ret;
 460
 461         for (i = 0; i < ios->comps->numdevs; i++) {
 462                 struct osd_request *or;
 463
 464                 or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
 465                 if (unlikely(!or)) {
 466                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
 467                         ret = -ENOMEM;
 468                         goto out;
 469                 }
 470                 ios->per_dev[i].or = or;
 471                 ios->numdevs++;
 472
 473                 osd_req_create_object(or, _ios_obj(ios, i));
 474         }
 475         ret = exofs_io_execute(ios);
 476
 477 out:
 478         return ret;
 479 }
 480
 481 int exofs_sbi_remove(struct exofs_io_state *ios)
 482 {
 483         int i, ret;
 484
 485         for (i = 0; i < ios->comps->numdevs; i++) {
 486                 struct osd_request *or;
 487
 488                 or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
 489                 if (unlikely(!or)) {
 490                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
 491                         ret = -ENOMEM;
 492                         goto out;
 493                 }
 494                 ios->per_dev[i].or = or;
 495                 ios->numdevs++;
 496
 497                 osd_req_remove_object(or, _ios_obj(ios, i));
 498         }
 499         ret = exofs_io_execute(ios);
 500
 501 out:
 502         return ret;
 503 }
 504
 505 static int _sbi_write_mirror(struct exofs_io_state *ios, int cur_comp)
 506 {
 507         struct exofs_per_dev_state *master_dev = &ios->per_dev[cur_comp];
 508         unsigned dev = ios->per_dev[cur_comp].dev;
 509         unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
 510         int ret = 0;
 511
 512         if (ios->pages && !master_dev->length)
 513                 return 0; /* Just an empty slot */
 514
 515         for (; cur_comp < last_comp; ++cur_comp, ++dev) {
 516                 struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 517                 struct osd_request *or;
 518
 519                 or = osd_start_request(_ios_od(ios, dev), GFP_KERNEL);
 520                 if (unlikely(!or)) {
 521                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
 522                         ret = -ENOMEM;
 523                         goto out;
 524                 }
 525                 per_dev->or = or;
 526                 per_dev->offset = master_dev->offset;
 527
 528                 if (ios->pages) {
 529                         struct bio *bio;
 530
 531                         if (per_dev != master_dev) {
 532                                 bio = bio_kmalloc(GFP_KERNEL,
 533                                                   master_dev->bio->bi_max_vecs);
 534                                 if (unlikely(!bio)) {
 535                                         EXOFS_DBGMSG(
 536                                               "Failed to allocate BIO size=%u\n",
 537                                               master_dev->bio->bi_max_vecs);
 538                                         ret = -ENOMEM;
 539                                         goto out;
 540                                 }
 541
 542                                 __bio_clone(bio, master_dev->bio);
 543                                 bio->bi_bdev = NULL;
 544                                 bio->bi_next = NULL;
 545                                 per_dev->length = master_dev->length;
 546                                 per_dev->bio =  bio;
 547                                 per_dev->dev = dev;
 548                         } else {
 549                                 bio = master_dev->bio;
 550                                 /* FIXME: bio_set_dir() */
 551                                 bio->bi_rw |= REQ_WRITE;
 552                         }
 553
 554                         osd_req_write(or, _ios_obj(ios, dev), per_dev->offset,
 555                                       bio, per_dev->length);
 556                         EXOFS_DBGMSG("write(0x%llx) offset=0x%llx "
 557                                       "length=0x%llx dev=%d\n",
 558                                      _LLU(_ios_obj(ios, dev)->id),
 559                                      _LLU(per_dev->offset),
 560                                      _LLU(per_dev->length), dev);
 561                 } else if (ios->kern_buff) {
 562                         ret = osd_req_write_kern(or, _ios_obj(ios, dev),
 563                                                  per_dev->offset,
 564                                                  ios->kern_buff, ios->length);
 565                         if (unlikely(ret))
 566                                 goto out;
 567                         EXOFS_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
 568                                       "length=0x%llx dev=%d\n",
 569                                      _LLU(_ios_obj(ios, dev)->id),
 570                                      _LLU(per_dev->offset),
 571                                      _LLU(ios->length), dev);
 572                 } else {
 573                         osd_req_set_attributes(or, _ios_obj(ios, dev));
 574                         EXOFS_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
 575                                      _LLU(_ios_obj(ios, dev)->id),
 576                                      ios->out_attr_len, dev);
 577                 }
 578
 579                 if (ios->out_attr)
 580                         osd_req_add_set_attr_list(or, ios->out_attr,
 581                                                   ios->out_attr_len);
 582
 583                 if (ios->in_attr)
 584                         osd_req_add_get_attr_list(or, ios->in_attr,
 585                                                   ios->in_attr_len);
 586         }
 587
 588 out:
 589         return ret;
 590 }
 591
 592 int exofs_sbi_write(struct exofs_io_state *ios)
 593 {
 594         int i;
 595         int ret;
 596
 597         ret = _prepare_for_striping(ios);
 598         if (unlikely(ret))
 599                 return ret;
 600
 601         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
 602                 ret = _sbi_write_mirror(ios, i);
 603                 if (unlikely(ret))
 604                         return ret;
 605         }
 606
 607         ret = exofs_io_execute(ios);
 608         return ret;
 609 }
 610
 611 static int _sbi_read_mirror(struct exofs_io_state *ios, unsigned cur_comp)
 612 {
 613         struct osd_request *or;
 614         struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 615         struct osd_obj_id *obj = _ios_obj(ios, cur_comp);
 616         unsigned first_dev = (unsigned)obj->id;
 617
 618         if (ios->pages && !per_dev->length)
 619                 return 0; /* Just an empty slot */
 620
 621         first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
 622         or = osd_start_request(_ios_od(ios, first_dev), GFP_KERNEL);
 623         if (unlikely(!or)) {
 624                 EXOFS_ERR("%s: osd_start_request failed\n", __func__);
 625                 return -ENOMEM;
 626         }
 627         per_dev->or = or;
 628
 629         if (ios->pages) {
 630                 osd_req_read(or, obj, per_dev->offset,
 631                                 per_dev->bio, per_dev->length);
 632                 EXOFS_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
 633                              " dev=%d\n", _LLU(obj->id),
 634                              _LLU(per_dev->offset), _LLU(per_dev->length),
 635                              first_dev);
 636         } else if (ios->kern_buff) {
 637                 int ret = osd_req_read_kern(or, obj, per_dev->offset,
 638                                             ios->kern_buff, ios->length);
 639                 EXOFS_DBGMSG2("read_kern(0x%llx) offset=0x%llx "
 640                               "length=0x%llx dev=%d ret=>%d\n",
 641                               _LLU(obj->id), _LLU(per_dev->offset),
 642                               _LLU(ios->length), first_dev, ret);
 643                 if (unlikely(ret))
 644                         return ret;
 645         } else {
 646                 osd_req_get_attributes(or, obj);
 647                 EXOFS_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
 648                               _LLU(obj->id),
 649                               ios->in_attr_len, first_dev);
 650         }
 651         if (ios->out_attr)
 652                 osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);
 653
 654         if (ios->in_attr)
 655                 osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);
 656
 657         return 0;
 658 }
 659
 660 int exofs_sbi_read(struct exofs_io_state *ios)
 661 {
 662         int i;
 663         int ret;
 664
 665         ret = _prepare_for_striping(ios);
 666         if (unlikely(ret))
 667                 return ret;
 668
 669         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
 670                 ret = _sbi_read_mirror(ios, i);
 671                 if (unlikely(ret))
 672                         return ret;
 673         }
 674
 675         ret = exofs_io_execute(ios);
 676         return ret;
 677 }
 678
 679 int extract_attr_from_ios(struct exofs_io_state *ios, struct osd_attr *attr)
 680 {
 681         struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
 682         void *iter = NULL;
 683         int nelem;
 684
 685         do {
 686                 nelem = 1;
 687                 osd_req_decode_get_attr_list(ios->per_dev[0].or,
 688                                              &cur_attr, &nelem, &iter);
 689                 if ((cur_attr.attr_page == attr->attr_page) &&
 690                     (cur_attr.attr_id == attr->attr_id)) {
 691                         attr->len = cur_attr.len;
 692                         attr->val_ptr = cur_attr.val_ptr;
 693                         return 0;
 694                 }
 695         } while (iter);
 696
 697         return -EIO;
 698 }
 699
 700 static int _truncate_mirrors(struct exofs_io_state *ios, unsigned cur_comp,
 701                              struct osd_attr *attr)
 702 {
 703         int last_comp = cur_comp + ios->layout->mirrors_p1;
 704
 705         for (; cur_comp < last_comp; ++cur_comp) {
 706                 struct exofs_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 707                 struct osd_request *or;
 708
 709                 or = osd_start_request(_ios_od(ios, cur_comp), GFP_KERNEL);
 710                 if (unlikely(!or)) {
 711                         EXOFS_ERR("%s: osd_start_request failed\n", __func__);
 712                         return -ENOMEM;
 713                 }
 714                 per_dev->or = or;
 715
 716                 osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
 717                 osd_req_add_set_attr_list(or, attr, 1);
 718         }
 719
 720         return 0;
 721 }
 722
 723 struct _trunc_info {
 724         struct _striping_info si;
 725         u64 prev_group_obj_off;
 726         u64 next_group_obj_off;
 727
 728         unsigned first_group_dev;
 729         unsigned nex_group_dev;
 730         unsigned max_devs;
 731 };
 732
 733 void _calc_trunk_info(struct exofs_layout *layout, u64 file_offset,
 734                        struct _trunc_info *ti)
 735 {
 736         unsigned stripe_unit = layout->stripe_unit;
 737
 738         _calc_stripe_info(layout, file_offset, &ti->si);
 739
 740         ti->prev_group_obj_off = ti->si.M * stripe_unit;
 741         ti->next_group_obj_off = ti->si.M ? (ti->si.M - 1) * stripe_unit : 0;
 742
 743         ti->first_group_dev = ti->si.dev - (ti->si.dev % layout->group_width);
 744         ti->nex_group_dev = ti->first_group_dev + layout->group_width;
 745         ti->max_devs = layout->group_width * layout->group_count;
 746 }
 747
 748 int exofs_truncate(struct exofs_layout *layout, struct exofs_components *comps,
 749                    u64 size)
 750 {
 751         struct exofs_io_state *ios;
 752         struct exofs_trunc_attr {
 753                 struct osd_attr attr;
 754                 __be64 newsize;
 755         } *size_attrs;
 756         struct _trunc_info ti;
 757         int i, ret;
 758
 759         ret = exofs_get_io_state(layout, comps, &ios);
 760         if (unlikely(ret))
 761                 return ret;
 762
 763         _calc_trunk_info(ios->layout, size, &ti);
 764
 765         size_attrs = kcalloc(ti.max_devs, sizeof(*size_attrs),
 766                              GFP_KERNEL);
 767         if (unlikely(!size_attrs)) {
 768                 ret = -ENOMEM;
 769                 goto out;
 770         }
 771
 772         ios->numdevs = ios->comps->numdevs;
 773
 774         for (i = 0; i < ti.max_devs; ++i) {
 775                 struct exofs_trunc_attr *size_attr = &size_attrs[i];
 776                 u64 obj_size;
 777
 778                 if (i < ti.first_group_dev)
 779                         obj_size = ti.prev_group_obj_off;
 780                 else if (i >= ti.nex_group_dev)
 781                         obj_size = ti.next_group_obj_off;
 782                 else if (i < ti.si.dev) /* dev within this group */
 783                         obj_size = ti.si.obj_offset +
 784                                       ios->layout->stripe_unit - ti.si.unit_off;
 785                 else if (i == ti.si.dev)
 786                         obj_size = ti.si.obj_offset;
 787                 else /* i > ti.dev */
 788                         obj_size = ti.si.obj_offset - ti.si.unit_off;
 789
 790                 size_attr->newsize = cpu_to_be64(obj_size);
 791                 size_attr->attr = g_attr_logical_length;
 792                 size_attr->attr.val_ptr = &size_attr->newsize;
 793
 794                 EXOFS_DBGMSG("trunc(0x%llx) obj_offset=0x%llx dev=%d\n",
 795                              _LLU(comps->comps->obj.id), _LLU(obj_size), i);
 796                 ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
 797                                         &size_attr->attr);
 798                 if (unlikely(ret))
 799                         goto out;
 800         }
 801         ret = exofs_io_execute(ios);
 802
 803 out:
 804         kfree(size_attrs);
 805         exofs_put_io_state(ios);
 806         return ret;
 807 }
 808
 809 const struct osd_attr g_attr_logical_length = ATTR_DEF(
 810         OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);