fs/exofs/ore.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 <asm/div64.h>
  27
  28 #include <scsi/osd_ore.h>
  29
  30 #define ORE_ERR(fmt, a...) printk(KERN_ERR "ore: " fmt, ##a)
  31
  32 #ifdef CONFIG_EXOFS_DEBUG
  33 #define ORE_DBGMSG(fmt, a...) \
  34         printk(KERN_NOTICE "ore @%s:%d: " fmt, __func__, __LINE__, ##a)
  35 #else
  36 #define ORE_DBGMSG(fmt, a...) \
  37         do { if (0) printk(fmt, ##a); } while (0)
  38 #endif
  39
  40 /* u64 has problems with printk this will cast it to unsigned long long */
  41 #define _LLU(x) (unsigned long long)(x)
  42
  43 #define ORE_DBGMSG2(M...) do {} while (0)
  44 /* #define ORE_DBGMSG2 ORE_DBGMSG */
  45
  46 MODULE_AUTHOR("Boaz Harrosh <bharrosh@panasas.com>");
  47 MODULE_DESCRIPTION("Objects Raid Engine ore.ko");
  48 MODULE_LICENSE("GPL");
  49
  50 static void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,
  51                                  struct ore_striping_info *si);
  52
  53 static u8 *_ios_cred(struct ore_io_state *ios, unsigned index)
  54 {
  55         return ios->oc->comps[index & ios->oc->single_comp].cred;
  56 }
  57
  58 static struct osd_obj_id *_ios_obj(struct ore_io_state *ios, unsigned index)
  59 {
  60         return &ios->oc->comps[index & ios->oc->single_comp].obj;
  61 }
  62
  63 static struct osd_dev *_ios_od(struct ore_io_state *ios, unsigned index)
  64 {
  65         return ore_comp_dev(ios->oc, index);
  66 }
  67
  68 static int  _get_io_state(struct ore_layout *layout,
  69                           struct ore_components *oc, unsigned numdevs,
  70                           struct ore_io_state **pios)
  71 {
  72         struct ore_io_state *ios;
  73
  74         /*TODO: Maybe use kmem_cach per sbi of size
  75          * exofs_io_state_size(layout->s_numdevs)
  76          */
  77         ios = kzalloc(ore_io_state_size(numdevs), GFP_KERNEL);
  78         if (unlikely(!ios)) {
  79                 ORE_DBGMSG("Failed kzalloc bytes=%d\n",
  80                            ore_io_state_size(numdevs));
  81                 *pios = NULL;
  82                 return -ENOMEM;
  83         }
  84
  85         ios->layout = layout;
  86         ios->oc = oc;
  87         *pios = ios;
  88         return 0;
  89 }
  90
  91 /* Allocate an io_state for only a single group of devices
  92  *
  93  * If a user needs to call ore_read/write() this version must be used becase it
  94  * allocates extra stuff for striping and raid.
  95  * The ore might decide to only IO less then @length bytes do to alignmets
  96  * and constrains as follows:
  97  * - The IO cannot cross group boundary.
  98  * - In raid5/6 The end of the IO must align at end of a stripe eg.
  99  *   (@offset + @length) % strip_size == 0. Or the complete range is within a
 100  *   single stripe.
 101  * - Memory condition only permitted a shorter IO. (A user can use @length=~0
 102  *   And check the returned ios->length for max_io_size.)
 103  *
 104  * The caller must check returned ios->length (and/or ios->nr_pages) and
 105  * re-issue these pages that fall outside of ios->length
 106  */
 107 int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,
 108                       bool is_reading, u64 offset, u64 length,
 109                       struct ore_io_state **pios)
 110 {
 111         struct ore_io_state *ios;
 112         unsigned numdevs = layout->group_width * layout->mirrors_p1;
 113         int ret;
 114
 115         ret = _get_io_state(layout, oc, numdevs, pios);
 116         if (unlikely(ret))
 117                 return ret;
 118
 119         ios = *pios;
 120         ios->reading = is_reading;
 121         ios->offset = offset;
 122
 123         if (length) {
 124                 ore_calc_stripe_info(layout, offset, &ios->si);
 125                 ios->length = (length <= ios->si.group_length) ? length :
 126                                                         ios->si.group_length;
 127                 ios->nr_pages = (ios->length + PAGE_SIZE - 1) / PAGE_SIZE;
 128         }
 129
 130         return 0;
 131 }
 132 EXPORT_SYMBOL(ore_get_rw_state);
 133
 134 /* Allocate an io_state for all the devices in the comps array
 135  *
 136  * This version of io_state allocation is used mostly by create/remove
 137  * and trunc where we currently need all the devices. The only wastful
 138  * bit is the read/write_attributes with no IO. Those sites should
 139  * be converted to use ore_get_rw_state() with length=0
 140  */
 141 int  ore_get_io_state(struct ore_layout *layout, struct ore_components *oc,
 142                       struct ore_io_state **pios)
 143 {
 144         return _get_io_state(layout, oc, oc->numdevs, pios);
 145 }
 146 EXPORT_SYMBOL(ore_get_io_state);
 147
 148 void ore_put_io_state(struct ore_io_state *ios)
 149 {
 150         if (ios) {
 151                 unsigned i;
 152
 153                 for (i = 0; i < ios->numdevs; i++) {
 154                         struct ore_per_dev_state *per_dev = &ios->per_dev[i];
 155
 156                         if (per_dev->or)
 157                                 osd_end_request(per_dev->or);
 158                         if (per_dev->bio)
 159                                 bio_put(per_dev->bio);
 160                 }
 161
 162                 kfree(ios);
 163         }
 164 }
 165 EXPORT_SYMBOL(ore_put_io_state);
 166
 167 static void _sync_done(struct ore_io_state *ios, void *p)
 168 {
 169         struct completion *waiting = p;
 170
 171         complete(waiting);
 172 }
 173
 174 static void _last_io(struct kref *kref)
 175 {
 176         struct ore_io_state *ios = container_of(
 177                                         kref, struct ore_io_state, kref);
 178
 179         ios->done(ios, ios->private);
 180 }
 181
 182 static void _done_io(struct osd_request *or, void *p)
 183 {
 184         struct ore_io_state *ios = p;
 185
 186         kref_put(&ios->kref, _last_io);
 187 }
 188
 189 static int ore_io_execute(struct ore_io_state *ios)
 190 {
 191         DECLARE_COMPLETION_ONSTACK(wait);
 192         bool sync = (ios->done == NULL);
 193         int i, ret;
 194
 195         if (sync) {
 196                 ios->done = _sync_done;
 197                 ios->private = &wait;
 198         }
 199
 200         for (i = 0; i < ios->numdevs; i++) {
 201                 struct osd_request *or = ios->per_dev[i].or;
 202                 if (unlikely(!or))
 203                         continue;
 204
 205                 ret = osd_finalize_request(or, 0, _ios_cred(ios, i), NULL);
 206                 if (unlikely(ret)) {
 207                         ORE_DBGMSG("Failed to osd_finalize_request() => %d\n",
 208                                      ret);
 209                         return ret;
 210                 }
 211         }
 212
 213         kref_init(&ios->kref);
 214
 215         for (i = 0; i < ios->numdevs; i++) {
 216                 struct osd_request *or = ios->per_dev[i].or;
 217                 if (unlikely(!or))
 218                         continue;
 219
 220                 kref_get(&ios->kref);
 221                 osd_execute_request_async(or, _done_io, ios);
 222         }
 223
 224         kref_put(&ios->kref, _last_io);
 225         ret = 0;
 226
 227         if (sync) {
 228                 wait_for_completion(&wait);
 229                 ret = ore_check_io(ios, NULL);
 230         }
 231         return ret;
 232 }
 233
 234 static void _clear_bio(struct bio *bio)
 235 {
 236         struct bio_vec *bv;
 237         unsigned i;
 238
 239         __bio_for_each_segment(bv, bio, i, 0) {
 240                 unsigned this_count = bv->bv_len;
 241
 242                 if (likely(PAGE_SIZE == this_count))
 243                         clear_highpage(bv->bv_page);
 244                 else
 245                         zero_user(bv->bv_page, bv->bv_offset, this_count);
 246         }
 247 }
 248
 249 int ore_check_io(struct ore_io_state *ios, u64 *resid)
 250 {
 251         enum osd_err_priority acumulated_osd_err = 0;
 252         int acumulated_lin_err = 0;
 253         int i;
 254
 255         for (i = 0; i < ios->numdevs; i++) {
 256                 struct osd_sense_info osi;
 257                 struct osd_request *or = ios->per_dev[i].or;
 258                 int ret;
 259
 260                 if (unlikely(!or))
 261                         continue;
 262
 263                 ret = osd_req_decode_sense(or, &osi);
 264                 if (likely(!ret))
 265                         continue;
 266
 267                 if (OSD_ERR_PRI_CLEAR_PAGES == osi.osd_err_pri) {
 268                         /* start read offset passed endof file */
 269                         _clear_bio(ios->per_dev[i].bio);
 270                         ORE_DBGMSG("start read offset passed end of file "
 271                                 "offset=0x%llx, length=0x%llx\n",
 272                                 _LLU(ios->per_dev[i].offset),
 273                                 _LLU(ios->per_dev[i].length));
 274
 275                         continue; /* we recovered */
 276                 }
 277
 278                 if (osi.osd_err_pri >= acumulated_osd_err) {
 279                         acumulated_osd_err = osi.osd_err_pri;
 280                         acumulated_lin_err = ret;
 281                 }
 282         }
 283
 284         /* TODO: raid specific residual calculations */
 285         if (resid) {
 286                 if (likely(!acumulated_lin_err))
 287                         *resid = 0;
 288                 else
 289                         *resid = ios->length;
 290         }
 291
 292         return acumulated_lin_err;
 293 }
 294 EXPORT_SYMBOL(ore_check_io);
 295
 296 /*
 297  * L - logical offset into the file
 298  *
 299  * U - The number of bytes in a stripe within a group
 300  *
 301  *      U = stripe_unit * group_width
 302  *
 303  * T - The number of bytes striped within a group of component objects
 304  *     (before advancing to the next group)
 305  *
 306  *      T = stripe_unit * group_width * group_depth
 307  *
 308  * S - The number of bytes striped across all component objects
 309  *     before the pattern repeats
 310  *
 311  *      S = stripe_unit * group_width * group_depth * group_count
 312  *
 313  * M - The "major" (i.e., across all components) stripe number
 314  *
 315  *      M = L / S
 316  *
 317  * G - Counts the groups from the beginning of the major stripe
 318  *
 319  *      G = (L - (M * S)) / T   [or (L % S) / T]
 320  *
 321  * H - The byte offset within the group
 322  *
 323  *      H = (L - (M * S)) % T   [or (L % S) % T]
 324  *
 325  * N - The "minor" (i.e., across the group) stripe number
 326  *
 327  *      N = H / U
 328  *
 329  * C - The component index coresponding to L
 330  *
 331  *      C = (H - (N * U)) / stripe_unit + G * group_width
 332  *      [or (L % U) / stripe_unit + G * group_width]
 333  *
 334  * O - The component offset coresponding to L
 335  *
 336  *      O = L % stripe_unit + N * stripe_unit + M * group_depth * stripe_unit
 337  */
 338 static void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,
 339                                  struct ore_striping_info *si)
 340 {
 341         u32     stripe_unit = layout->stripe_unit;
 342         u32     group_width = layout->group_width;
 343         u64     group_depth = layout->group_depth;
 344
 345         u32     U = stripe_unit * group_width;
 346         u64     T = U * group_depth;
 347         u64     S = T * layout->group_count;
 348         u64     M = div64_u64(file_offset, S);
 349
 350         /*
 351         G = (L - (M * S)) / T
 352         H = (L - (M * S)) % T
 353         */
 354         u64     LmodS = file_offset - M * S;
 355         u32     G = div64_u64(LmodS, T);
 356         u64     H = LmodS - G * T;
 357
 358         u32     N = div_u64(H, U);
 359
 360         /* "H - (N * U)" is just "H % U" so it's bound to u32 */
 361         si->dev = (u32)(H - (N * U)) / stripe_unit + G * group_width;
 362         si->dev *= layout->mirrors_p1;
 363
 364         div_u64_rem(file_offset, stripe_unit, &si->unit_off);
 365
 366         si->obj_offset = si->unit_off + (N * stripe_unit) +
 367                                   (M * group_depth * stripe_unit);
 368
 369         si->group_length = T - H;
 370         si->M = M;
 371 }
 372
 373 static int _add_stripe_unit(struct ore_io_state *ios,  unsigned *cur_pg,
 374                 unsigned pgbase, struct ore_per_dev_state *per_dev,
 375                 int cur_len)
 376 {
 377         unsigned pg = *cur_pg;
 378         struct request_queue *q =
 379                         osd_request_queue(_ios_od(ios, per_dev->dev));
 380         unsigned len = cur_len;
 381         int ret;
 382
 383         if (per_dev->bio == NULL) {
 384                 unsigned pages_in_stripe = ios->layout->group_width *
 385                                         (ios->layout->stripe_unit / PAGE_SIZE);
 386                 unsigned bio_size = (ios->nr_pages + pages_in_stripe) /
 387                                                 ios->layout->group_width;
 388
 389                 per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
 390                 if (unlikely(!per_dev->bio)) {
 391                         ORE_DBGMSG("Failed to allocate BIO size=%u\n",
 392                                      bio_size);
 393                         ret = -ENOMEM;
 394                         goto out;
 395                 }
 396         }
 397
 398         while (cur_len > 0) {
 399                 unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
 400                 unsigned added_len;
 401
 402                 BUG_ON(ios->nr_pages <= pg);
 403                 cur_len -= pglen;
 404
 405                 added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
 406                                             pglen, pgbase);
 407                 if (unlikely(pglen != added_len)) {
 408                         ret = -ENOMEM;
 409                         goto out;
 410                 }
 411                 pgbase = 0;
 412                 ++pg;
 413         }
 414         BUG_ON(cur_len);
 415
 416         per_dev->length += len;
 417         *cur_pg = pg;
 418         ret = 0;
 419 out:    /* we fail the complete unit on an error eg don't advance
 420          * per_dev->length and cur_pg. This means that we might have a bigger
 421          * bio than the CDB requested length (per_dev->length). That's fine
 422          * only the oposite is fatal.
 423          */
 424         return ret;
 425 }
 426
 427 static int _prepare_for_striping(struct ore_io_state *ios)
 428 {
 429         struct ore_striping_info *si = &ios->si;
 430         unsigned stripe_unit = ios->layout->stripe_unit;
 431         unsigned mirrors_p1 = ios->layout->mirrors_p1;
 432         unsigned devs_in_group = ios->layout->group_width * mirrors_p1;
 433         unsigned dev = si->dev;
 434         unsigned first_dev = dev - (dev % devs_in_group);
 435         unsigned cur_pg = ios->pages_consumed;
 436         u64 length = ios->length;
 437         int ret = 0;
 438
 439         if (!ios->pages) {
 440                 ios->numdevs = ios->layout->mirrors_p1;
 441                 return 0;
 442         }
 443
 444         BUG_ON(length > si->group_length);
 445
 446         while (length) {
 447                 unsigned comp = dev - first_dev;
 448                 struct ore_per_dev_state *per_dev = &ios->per_dev[comp];
 449                 unsigned cur_len, page_off = 0;
 450
 451                 if (!per_dev->length) {
 452                         per_dev->dev = dev;
 453                         if (dev < si->dev) {
 454                                 per_dev->offset = si->obj_offset + stripe_unit -
 455                                                                    si->unit_off;
 456                                 cur_len = stripe_unit;
 457                         } else if (dev == si->dev) {
 458                                 per_dev->offset = si->obj_offset;
 459                                 cur_len = stripe_unit - si->unit_off;
 460                                 page_off = si->unit_off & ~PAGE_MASK;
 461                                 BUG_ON(page_off && (page_off != ios->pgbase));
 462                         } else { /* dev > si->dev */
 463                                 per_dev->offset = si->obj_offset - si->unit_off;
 464                                 cur_len = stripe_unit;
 465                         }
 466                 } else {
 467                         cur_len = stripe_unit;
 468                 }
 469                 if (cur_len >= length)
 470                         cur_len = length;
 471
 472                 ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
 473                                        cur_len);
 474                 if (unlikely(ret))
 475                         goto out;
 476
 477                 dev += mirrors_p1;
 478                 dev = (dev % devs_in_group) + first_dev;
 479
 480                 length -= cur_len;
 481         }
 482 out:
 483         ios->numdevs = devs_in_group;
 484         ios->pages_consumed = cur_pg;
 485         if (unlikely(ret)) {
 486                 if (length == ios->length)
 487                         return ret;
 488                 else
 489                         ios->length -= length;
 490         }
 491         return 0;
 492 }
 493
 494 int ore_create(struct ore_io_state *ios)
 495 {
 496         int i, ret;
 497
 498         for (i = 0; i < ios->oc->numdevs; i++) {
 499                 struct osd_request *or;
 500
 501                 or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
 502                 if (unlikely(!or)) {
 503                         ORE_ERR("%s: osd_start_request failed\n", __func__);
 504                         ret = -ENOMEM;
 505                         goto out;
 506                 }
 507                 ios->per_dev[i].or = or;
 508                 ios->numdevs++;
 509
 510                 osd_req_create_object(or, _ios_obj(ios, i));
 511         }
 512         ret = ore_io_execute(ios);
 513
 514 out:
 515         return ret;
 516 }
 517 EXPORT_SYMBOL(ore_create);
 518
 519 int ore_remove(struct ore_io_state *ios)
 520 {
 521         int i, ret;
 522
 523         for (i = 0; i < ios->oc->numdevs; i++) {
 524                 struct osd_request *or;
 525
 526                 or = osd_start_request(_ios_od(ios, i), GFP_KERNEL);
 527                 if (unlikely(!or)) {
 528                         ORE_ERR("%s: osd_start_request failed\n", __func__);
 529                         ret = -ENOMEM;
 530                         goto out;
 531                 }
 532                 ios->per_dev[i].or = or;
 533                 ios->numdevs++;
 534
 535                 osd_req_remove_object(or, _ios_obj(ios, i));
 536         }
 537         ret = ore_io_execute(ios);
 538
 539 out:
 540         return ret;
 541 }
 542 EXPORT_SYMBOL(ore_remove);
 543
 544 static int _write_mirror(struct ore_io_state *ios, int cur_comp)
 545 {
 546         struct ore_per_dev_state *master_dev = &ios->per_dev[cur_comp];
 547         unsigned dev = ios->per_dev[cur_comp].dev;
 548         unsigned last_comp = cur_comp + ios->layout->mirrors_p1;
 549         int ret = 0;
 550
 551         if (ios->pages && !master_dev->length)
 552                 return 0; /* Just an empty slot */
 553
 554         for (; cur_comp < last_comp; ++cur_comp, ++dev) {
 555                 struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 556                 struct osd_request *or;
 557
 558                 or = osd_start_request(_ios_od(ios, dev), GFP_KERNEL);
 559                 if (unlikely(!or)) {
 560                         ORE_ERR("%s: osd_start_request failed\n", __func__);
 561                         ret = -ENOMEM;
 562                         goto out;
 563                 }
 564                 per_dev->or = or;
 565
 566                 if (ios->pages) {
 567                         struct bio *bio;
 568
 569                         if (per_dev != master_dev) {
 570                                 bio = bio_kmalloc(GFP_KERNEL,
 571                                                   master_dev->bio->bi_max_vecs);
 572                                 if (unlikely(!bio)) {
 573                                         ORE_DBGMSG(
 574                                               "Failed to allocate BIO size=%u\n",
 575                                               master_dev->bio->bi_max_vecs);
 576                                         ret = -ENOMEM;
 577                                         goto out;
 578                                 }
 579
 580                                 __bio_clone(bio, master_dev->bio);
 581                                 bio->bi_bdev = NULL;
 582                                 bio->bi_next = NULL;
 583                                 per_dev->offset = master_dev->offset;
 584                                 per_dev->length = master_dev->length;
 585                                 per_dev->bio =  bio;
 586                                 per_dev->dev = dev;
 587                         } else {
 588                                 bio = master_dev->bio;
 589                                 /* FIXME: bio_set_dir() */
 590                                 bio->bi_rw |= REQ_WRITE;
 591                         }
 592
 593                         osd_req_write(or, _ios_obj(ios, dev), per_dev->offset,
 594                                       bio, per_dev->length);
 595                         ORE_DBGMSG("write(0x%llx) offset=0x%llx "
 596                                       "length=0x%llx dev=%d\n",
 597                                      _LLU(_ios_obj(ios, dev)->id),
 598                                      _LLU(per_dev->offset),
 599                                      _LLU(per_dev->length), dev);
 600                 } else if (ios->kern_buff) {
 601                         per_dev->offset = ios->si.obj_offset;
 602                         per_dev->dev = ios->si.dev + dev;
 603
 604                         /* no cross device without page array */
 605                         BUG_ON((ios->layout->group_width > 1) &&
 606                                (ios->si.unit_off + ios->length >
 607                                 ios->layout->stripe_unit));
 608
 609                         ret = osd_req_write_kern(or, _ios_obj(ios, per_dev->dev),
 610                                                  per_dev->offset,
 611                                                  ios->kern_buff, ios->length);
 612                         if (unlikely(ret))
 613                                 goto out;
 614                         ORE_DBGMSG2("write_kern(0x%llx) offset=0x%llx "
 615                                       "length=0x%llx dev=%d\n",
 616                                      _LLU(_ios_obj(ios, dev)->id),
 617                                      _LLU(per_dev->offset),
 618                                      _LLU(ios->length), per_dev->dev);
 619                 } else {
 620                         osd_req_set_attributes(or, _ios_obj(ios, dev));
 621                         ORE_DBGMSG2("obj(0x%llx) set_attributes=%d dev=%d\n",
 622                                      _LLU(_ios_obj(ios, dev)->id),
 623                                      ios->out_attr_len, dev);
 624                 }
 625
 626                 if (ios->out_attr)
 627                         osd_req_add_set_attr_list(or, ios->out_attr,
 628                                                   ios->out_attr_len);
 629
 630                 if (ios->in_attr)
 631                         osd_req_add_get_attr_list(or, ios->in_attr,
 632                                                   ios->in_attr_len);
 633         }
 634
 635 out:
 636         return ret;
 637 }
 638
 639 int ore_write(struct ore_io_state *ios)
 640 {
 641         int i;
 642         int ret;
 643
 644         ret = _prepare_for_striping(ios);
 645         if (unlikely(ret))
 646                 return ret;
 647
 648         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
 649                 ret = _write_mirror(ios, i);
 650                 if (unlikely(ret))
 651                         return ret;
 652         }
 653
 654         ret = ore_io_execute(ios);
 655         return ret;
 656 }
 657 EXPORT_SYMBOL(ore_write);
 658
 659 static int _read_mirror(struct ore_io_state *ios, unsigned cur_comp)
 660 {
 661         struct osd_request *or;
 662         struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 663         struct osd_obj_id *obj = _ios_obj(ios, cur_comp);
 664         unsigned first_dev = (unsigned)obj->id;
 665
 666         if (ios->pages && !per_dev->length)
 667                 return 0; /* Just an empty slot */
 668
 669         first_dev = per_dev->dev + first_dev % ios->layout->mirrors_p1;
 670         or = osd_start_request(_ios_od(ios, first_dev), GFP_KERNEL);
 671         if (unlikely(!or)) {
 672                 ORE_ERR("%s: osd_start_request failed\n", __func__);
 673                 return -ENOMEM;
 674         }
 675         per_dev->or = or;
 676
 677         if (ios->pages) {
 678                 osd_req_read(or, obj, per_dev->offset,
 679                                 per_dev->bio, per_dev->length);
 680                 ORE_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
 681                              " dev=%d\n", _LLU(obj->id),
 682                              _LLU(per_dev->offset), _LLU(per_dev->length),
 683                              first_dev);
 684         } else {
 685                 BUG_ON(ios->kern_buff);
 686
 687                 osd_req_get_attributes(or, obj);
 688                 ORE_DBGMSG2("obj(0x%llx) get_attributes=%d dev=%d\n",
 689                               _LLU(obj->id),
 690                               ios->in_attr_len, first_dev);
 691         }
 692         if (ios->out_attr)
 693                 osd_req_add_set_attr_list(or, ios->out_attr, ios->out_attr_len);
 694
 695         if (ios->in_attr)
 696                 osd_req_add_get_attr_list(or, ios->in_attr, ios->in_attr_len);
 697
 698         return 0;
 699 }
 700
 701 int ore_read(struct ore_io_state *ios)
 702 {
 703         int i;
 704         int ret;
 705
 706         ret = _prepare_for_striping(ios);
 707         if (unlikely(ret))
 708                 return ret;
 709
 710         for (i = 0; i < ios->numdevs; i += ios->layout->mirrors_p1) {
 711                 ret = _read_mirror(ios, i);
 712                 if (unlikely(ret))
 713                         return ret;
 714         }
 715
 716         ret = ore_io_execute(ios);
 717         return ret;
 718 }
 719 EXPORT_SYMBOL(ore_read);
 720
 721 int extract_attr_from_ios(struct ore_io_state *ios, struct osd_attr *attr)
 722 {
 723         struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
 724         void *iter = NULL;
 725         int nelem;
 726
 727         do {
 728                 nelem = 1;
 729                 osd_req_decode_get_attr_list(ios->per_dev[0].or,
 730                                              &cur_attr, &nelem, &iter);
 731                 if ((cur_attr.attr_page == attr->attr_page) &&
 732                     (cur_attr.attr_id == attr->attr_id)) {
 733                         attr->len = cur_attr.len;
 734                         attr->val_ptr = cur_attr.val_ptr;
 735                         return 0;
 736                 }
 737         } while (iter);
 738
 739         return -EIO;
 740 }
 741 EXPORT_SYMBOL(extract_attr_from_ios);
 742
 743 static int _truncate_mirrors(struct ore_io_state *ios, unsigned cur_comp,
 744                              struct osd_attr *attr)
 745 {
 746         int last_comp = cur_comp + ios->layout->mirrors_p1;
 747
 748         for (; cur_comp < last_comp; ++cur_comp) {
 749                 struct ore_per_dev_state *per_dev = &ios->per_dev[cur_comp];
 750                 struct osd_request *or;
 751
 752                 or = osd_start_request(_ios_od(ios, cur_comp), GFP_KERNEL);
 753                 if (unlikely(!or)) {
 754                         ORE_ERR("%s: osd_start_request failed\n", __func__);
 755                         return -ENOMEM;
 756                 }
 757                 per_dev->or = or;
 758
 759                 osd_req_set_attributes(or, _ios_obj(ios, cur_comp));
 760                 osd_req_add_set_attr_list(or, attr, 1);
 761         }
 762
 763         return 0;
 764 }
 765
 766 struct _trunc_info {
 767         struct ore_striping_info si;
 768         u64 prev_group_obj_off;
 769         u64 next_group_obj_off;
 770
 771         unsigned first_group_dev;
 772         unsigned nex_group_dev;
 773 };
 774
 775 static void _calc_trunk_info(struct ore_layout *layout, u64 file_offset,
 776                              struct _trunc_info *ti)
 777 {
 778         unsigned stripe_unit = layout->stripe_unit;
 779
 780         ore_calc_stripe_info(layout, file_offset, &ti->si);
 781
 782         ti->prev_group_obj_off = ti->si.M * stripe_unit;
 783         ti->next_group_obj_off = ti->si.M ? (ti->si.M - 1) * stripe_unit : 0;
 784
 785         ti->first_group_dev = ti->si.dev - (ti->si.dev % layout->group_width);
 786         ti->nex_group_dev = ti->first_group_dev + layout->group_width;
 787 }
 788
 789 int ore_truncate(struct ore_layout *layout, struct ore_components *oc,
 790                    u64 size)
 791 {
 792         struct ore_io_state *ios;
 793         struct exofs_trunc_attr {
 794                 struct osd_attr attr;
 795                 __be64 newsize;
 796         } *size_attrs;
 797         struct _trunc_info ti;
 798         int i, ret;
 799
 800         ret = ore_get_io_state(layout, oc, &ios);
 801         if (unlikely(ret))
 802                 return ret;
 803
 804         _calc_trunk_info(ios->layout, size, &ti);
 805
 806         size_attrs = kcalloc(ios->oc->numdevs, sizeof(*size_attrs),
 807                              GFP_KERNEL);
 808         if (unlikely(!size_attrs)) {
 809                 ret = -ENOMEM;
 810                 goto out;
 811         }
 812
 813         ios->numdevs = ios->oc->numdevs;
 814
 815         for (i = 0; i < ios->numdevs; ++i) {
 816                 struct exofs_trunc_attr *size_attr = &size_attrs[i];
 817                 u64 obj_size;
 818
 819                 if (i < ti.first_group_dev)
 820                         obj_size = ti.prev_group_obj_off;
 821                 else if (i >= ti.nex_group_dev)
 822                         obj_size = ti.next_group_obj_off;
 823                 else if (i < ti.si.dev) /* dev within this group */
 824                         obj_size = ti.si.obj_offset +
 825                                       ios->layout->stripe_unit - ti.si.unit_off;
 826                 else if (i == ti.si.dev)
 827                         obj_size = ti.si.obj_offset;
 828                 else /* i > ti.dev */
 829                         obj_size = ti.si.obj_offset - ti.si.unit_off;
 830
 831                 size_attr->newsize = cpu_to_be64(obj_size);
 832                 size_attr->attr = g_attr_logical_length;
 833                 size_attr->attr.val_ptr = &size_attr->newsize;
 834
 835                 ORE_DBGMSG("trunc(0x%llx) obj_offset=0x%llx dev=%d\n",
 836                              _LLU(oc->comps->obj.id), _LLU(obj_size), i);
 837                 ret = _truncate_mirrors(ios, i * ios->layout->mirrors_p1,
 838                                         &size_attr->attr);
 839                 if (unlikely(ret))
 840                         goto out;
 841         }
 842         ret = ore_io_execute(ios);
 843
 844 out:
 845         kfree(size_attrs);
 846         ore_put_io_state(ios);
 847         return ret;
 848 }
 849 EXPORT_SYMBOL(ore_truncate);
 850
 851 const struct osd_attr g_attr_logical_length = ATTR_DEF(
 852         OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
 853 EXPORT_SYMBOL(g_attr_logical_length);