SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/exofs/inode.c

   1 /*
   2  * Copyright (C) 2005, 2006
   3  * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
   4  * Copyright (C) 2005, 2006
   5  * International Business Machines
   6  * Copyright (C) 2008, 2009
   7  * Boaz Harrosh <bharrosh@panasas.com>
   8  *
   9  * Copyrights for code taken from ext2:
  10  *     Copyright (C) 1992, 1993, 1994, 1995
  11  *     Remy Card (card@masi.ibp.fr)
  12  *     Laboratoire MASI - Institut Blaise Pascal
  13  *     Universite Pierre et Marie Curie (Paris VI)
  14  *     from
  15  *     linux/fs/minix/inode.c
  16  *     Copyright (C) 1991, 1992  Linus Torvalds
  17  *
  18  * This file is part of exofs.
  19  *
  20  * exofs is free software; you can redistribute it and/or modify
  21  * it under the terms of the GNU General Public License as published by
  22  * the Free Software Foundation.  Since it is based on ext2, and the only
  23  * valid version of GPL for the Linux kernel is version 2, the only valid
  24  * version of GPL for exofs is version 2.
  25  *
  26  * exofs is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  * GNU General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU General Public License
  32  * along with exofs; if not, write to the Free Software
  33  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  34  */
  35
  36 #include <linux/writeback.h>
  37 #include <linux/buffer_head.h>
  38 #include <scsi/scsi_device.h>
  39
  40 #include "exofs.h"
  41
  42 #ifdef CONFIG_EXOFS_DEBUG
  43 #  define EXOFS_DEBUG_OBJ_ISIZE 1
  44 #endif
  45
  46 struct page_collect {
  47         struct exofs_sb_info *sbi;
  48         struct request_queue *req_q;
  49         struct inode *inode;
  50         unsigned expected_pages;
  51
  52         struct bio *bio;
  53         unsigned nr_pages;
  54         unsigned long length;
  55         loff_t pg_first; /* keep 64bit also in 32-arches */
  56 };
  57
  58 static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
  59                 struct inode *inode)
  60 {
  61         struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
  62         struct request_queue *req_q = sbi->s_dev->scsi_device->request_queue;
  63
  64         pcol->sbi = sbi;
  65         pcol->req_q = req_q;
  66         pcol->inode = inode;
  67         pcol->expected_pages = expected_pages;
  68
  69         pcol->bio = NULL;
  70         pcol->nr_pages = 0;
  71         pcol->length = 0;
  72         pcol->pg_first = -1;
  73
  74         EXOFS_DBGMSG("_pcol_init ino=0x%lx expected_pages=%u\n", inode->i_ino,
  75                      expected_pages);
  76 }
  77
  78 static void _pcol_reset(struct page_collect *pcol)
  79 {
  80         pcol->expected_pages -= min(pcol->nr_pages, pcol->expected_pages);
  81
  82         pcol->bio = NULL;
  83         pcol->nr_pages = 0;
  84         pcol->length = 0;
  85         pcol->pg_first = -1;
  86         EXOFS_DBGMSG("_pcol_reset ino=0x%lx expected_pages=%u\n",
  87                      pcol->inode->i_ino, pcol->expected_pages);
  88
  89         /* this is probably the end of the loop but in writes
  90          * it might not end here. don't be left with nothing
  91          */
  92         if (!pcol->expected_pages)
  93                 pcol->expected_pages = 128;
  94 }
  95
  96 static int pcol_try_alloc(struct page_collect *pcol)
  97 {
  98         int pages = min_t(unsigned, pcol->expected_pages, BIO_MAX_PAGES);
  99
 100         for (; pages; pages >>= 1) {
 101                 pcol->bio = bio_alloc(GFP_KERNEL, pages);
 102                 if (likely(pcol->bio))
 103                         return 0;
 104         }
 105
 106         EXOFS_ERR("Failed to kcalloc expected_pages=%u\n",
 107                   pcol->expected_pages);
 108         return -ENOMEM;
 109 }
 110
 111 static void pcol_free(struct page_collect *pcol)
 112 {
 113         bio_put(pcol->bio);
 114         pcol->bio = NULL;
 115 }
 116
 117 static int pcol_add_page(struct page_collect *pcol, struct page *page,
 118                          unsigned len)
 119 {
 120         int added_len = bio_add_pc_page(pcol->req_q, pcol->bio, page, len, 0);
 121         if (unlikely(len != added_len))
 122                 return -ENOMEM;
 123
 124         ++pcol->nr_pages;
 125         pcol->length += len;
 126         return 0;
 127 }
 128
 129 static int update_read_page(struct page *page, int ret)
 130 {
 131         if (ret == 0) {
 132                 /* Everything is OK */
 133                 SetPageUptodate(page);
 134                 if (PageError(page))
 135                         ClearPageError(page);
 136         } else if (ret == -EFAULT) {
 137                 /* In this case we were trying to read something that wasn't on
 138                  * disk yet - return a page full of zeroes.  This should be OK,
 139                  * because the object should be empty (if there was a write
 140                  * before this read, the read would be waiting with the page
 141                  * locked */
 142                 clear_highpage(page);
 143
 144                 SetPageUptodate(page);
 145                 if (PageError(page))
 146                         ClearPageError(page);
 147                 ret = 0; /* recovered error */
 148                 EXOFS_DBGMSG("recovered read error\n");
 149         } else /* Error */
 150                 SetPageError(page);
 151
 152         return ret;
 153 }
 154
 155 static void update_write_page(struct page *page, int ret)
 156 {
 157         if (ret) {
 158                 mapping_set_error(page->mapping, ret);
 159                 SetPageError(page);
 160         }
 161         end_page_writeback(page);
 162 }
 163
 164 /* Called at the end of reads, to optionally unlock pages and update their
 165  * status.
 166  */
 167 static int __readpages_done(struct osd_request *or, struct page_collect *pcol,
 168                             bool do_unlock)
 169 {
 170         struct bio_vec *bvec;
 171         int i;
 172         u64 resid;
 173         u64 good_bytes;
 174         u64 length = 0;
 175         int ret = exofs_check_ok_resid(or, &resid, NULL);
 176
 177         osd_end_request(or);
 178
 179         if (likely(!ret))
 180                 good_bytes = pcol->length;
 181         else if (!resid)
 182                 good_bytes = 0;
 183         else
 184                 good_bytes = pcol->length - resid;
 185
 186         EXOFS_DBGMSG("readpages_done(0x%lx) good_bytes=0x%llx"
 187                      " length=0x%lx nr_pages=%u\n",
 188                      pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
 189                      pcol->nr_pages);
 190
 191         __bio_for_each_segment(bvec, pcol->bio, i, 0) {
 192                 struct page *page = bvec->bv_page;
 193                 struct inode *inode = page->mapping->host;
 194                 int page_stat;
 195
 196                 if (inode != pcol->inode)
 197                         continue; /* osd might add more pages at end */
 198
 199                 if (likely(length < good_bytes))
 200                         page_stat = 0;
 201                 else
 202                         page_stat = ret;
 203
 204                 EXOFS_DBGMSG("    readpages_done(0x%lx, 0x%lx) %s\n",
 205                           inode->i_ino, page->index,
 206                           page_stat ? "bad_bytes" : "good_bytes");
 207
 208                 ret = update_read_page(page, page_stat);
 209                 if (do_unlock)
 210                         unlock_page(page);
 211                 length += bvec->bv_len;
 212         }
 213
 214         pcol_free(pcol);
 215         EXOFS_DBGMSG("readpages_done END\n");
 216         return ret;
 217 }
 218
 219 /* callback of async reads */
 220 static void readpages_done(struct osd_request *or, void *p)
 221 {
 222         struct page_collect *pcol = p;
 223
 224         __readpages_done(or, pcol, true);
 225         atomic_dec(&pcol->sbi->s_curr_pending);
 226         kfree(p);
 227 }
 228
 229 static void _unlock_pcol_pages(struct page_collect *pcol, int ret, int rw)
 230 {
 231         struct bio_vec *bvec;
 232         int i;
 233
 234         __bio_for_each_segment(bvec, pcol->bio, i, 0) {
 235                 struct page *page = bvec->bv_page;
 236
 237                 if (rw == READ)
 238                         update_read_page(page, ret);
 239                 else
 240                         update_write_page(page, ret);
 241
 242                 unlock_page(page);
 243         }
 244         pcol_free(pcol);
 245 }
 246
 247 static int read_exec(struct page_collect *pcol, bool is_sync)
 248 {
 249         struct exofs_i_info *oi = exofs_i(pcol->inode);
 250         struct osd_obj_id obj = {pcol->sbi->s_pid,
 251                                         pcol->inode->i_ino + EXOFS_OBJ_OFF};
 252         struct osd_request *or = NULL;
 253         struct page_collect *pcol_copy = NULL;
 254         loff_t i_start = pcol->pg_first << PAGE_CACHE_SHIFT;
 255         int ret;
 256
 257         if (!pcol->bio)
 258                 return 0;
 259
 260         /* see comment in _readpage() about sync reads */
 261         WARN_ON(is_sync && (pcol->nr_pages != 1));
 262
 263         or = osd_start_request(pcol->sbi->s_dev, GFP_KERNEL);
 264         if (unlikely(!or)) {
 265                 ret = -ENOMEM;
 266                 goto err;
 267         }
 268
 269         osd_req_read(or, &obj, pcol->bio, i_start);
 270
 271         if (is_sync) {
 272                 exofs_sync_op(or, pcol->sbi->s_timeout, oi->i_cred);
 273                 return __readpages_done(or, pcol, false);
 274         }
 275
 276         pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
 277         if (!pcol_copy) {
 278                 ret = -ENOMEM;
 279                 goto err;
 280         }
 281
 282         *pcol_copy = *pcol;
 283         ret = exofs_async_op(or, readpages_done, pcol_copy, oi->i_cred);
 284         if (unlikely(ret))
 285                 goto err;
 286
 287         atomic_inc(&pcol->sbi->s_curr_pending);
 288
 289         EXOFS_DBGMSG("read_exec obj=0x%llx start=0x%llx length=0x%lx\n",
 290                   obj.id, _LLU(i_start), pcol->length);
 291
 292         /* pages ownership was passed to pcol_copy */
 293         _pcol_reset(pcol);
 294         return 0;
 295
 296 err:
 297         if (!is_sync)
 298                 _unlock_pcol_pages(pcol, ret, READ);
 299         kfree(pcol_copy);
 300         if (or)
 301                 osd_end_request(or);
 302         return ret;
 303 }
 304
 305 /* readpage_strip is called either directly from readpage() or by the VFS from
 306  * within read_cache_pages(), to add one more page to be read. It will try to
 307  * collect as many contiguous pages as posible. If a discontinuity is
 308  * encountered, or it runs out of resources, it will submit the previous segment
 309  * and will start a new collection. Eventually caller must submit the last
 310  * segment if present.
 311  */
 312 static int readpage_strip(void *data, struct page *page)
 313 {
 314         struct page_collect *pcol = data;
 315         struct inode *inode = pcol->inode;
 316         struct exofs_i_info *oi = exofs_i(inode);
 317         loff_t i_size = i_size_read(inode);
 318         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 319         size_t len;
 320         int ret;
 321
 322         /* FIXME: Just for debugging, will be removed */
 323         if (PageUptodate(page))
 324                 EXOFS_ERR("PageUptodate(0x%lx, 0x%lx)\n", pcol->inode->i_ino,
 325                           page->index);
 326
 327         if (page->index < end_index)
 328                 len = PAGE_CACHE_SIZE;
 329         else if (page->index == end_index)
 330                 len = i_size & ~PAGE_CACHE_MASK;
 331         else
 332                 len = 0;
 333
 334         if (!len || !obj_created(oi)) {
 335                 /* this will be out of bounds, or doesn't exist yet.
 336                  * Current page is cleared and the request is split
 337                  */
 338                 clear_highpage(page);
 339
 340                 SetPageUptodate(page);
 341                 if (PageError(page))
 342                         ClearPageError(page);
 343
 344                 unlock_page(page);
 345                 EXOFS_DBGMSG("readpage_strip(0x%lx, 0x%lx) empty page,"
 346                              " splitting\n", inode->i_ino, page->index);
 347
 348                 return read_exec(pcol, false);
 349         }
 350
 351 try_again:
 352
 353         if (unlikely(pcol->pg_first == -1)) {
 354                 pcol->pg_first = page->index;
 355         } else if (unlikely((pcol->pg_first + pcol->nr_pages) !=
 356                    page->index)) {
 357                 /* Discontinuity detected, split the request */
 358                 ret = read_exec(pcol, false);
 359                 if (unlikely(ret))
 360                         goto fail;
 361                 goto try_again;
 362         }
 363
 364         if (!pcol->bio) {
 365                 ret = pcol_try_alloc(pcol);
 366                 if (unlikely(ret))
 367                         goto fail;
 368         }
 369
 370         if (len != PAGE_CACHE_SIZE)
 371                 zero_user(page, len, PAGE_CACHE_SIZE - len);
 372
 373         EXOFS_DBGMSG("    readpage_strip(0x%lx, 0x%lx) len=0x%zx\n",
 374                      inode->i_ino, page->index, len);
 375
 376         ret = pcol_add_page(pcol, page, len);
 377         if (ret) {
 378                 EXOFS_DBGMSG("Failed pcol_add_page pages[i]=%p "
 379                           "this_len=0x%zx nr_pages=%u length=0x%lx\n",
 380                           page, len, pcol->nr_pages, pcol->length);
 381
 382                 /* split the request, and start again with current page */
 383                 ret = read_exec(pcol, false);
 384                 if (unlikely(ret))
 385                         goto fail;
 386
 387                 goto try_again;
 388         }
 389
 390         return 0;
 391
 392 fail:
 393         /* SetPageError(page); ??? */
 394         unlock_page(page);
 395         return ret;
 396 }
 397
 398 static int exofs_readpages(struct file *file, struct address_space *mapping,
 399                            struct list_head *pages, unsigned nr_pages)
 400 {
 401         struct page_collect pcol;
 402         int ret;
 403
 404         _pcol_init(&pcol, nr_pages, mapping->host);
 405
 406         ret = read_cache_pages(mapping, pages, readpage_strip, &pcol);
 407         if (ret) {
 408                 EXOFS_ERR("read_cache_pages => %d\n", ret);
 409                 return ret;
 410         }
 411
 412         return read_exec(&pcol, false);
 413 }
 414
 415 static int _readpage(struct page *page, bool is_sync)
 416 {
 417         struct page_collect pcol;
 418         int ret;
 419
 420         _pcol_init(&pcol, 1, page->mapping->host);
 421
 422         /* readpage_strip might call read_exec(,async) inside at several places
 423          * but this is safe for is_async=0 since read_exec will not do anything
 424          * when we have a single page.
 425          */
 426         ret = readpage_strip(&pcol, page);
 427         if (ret) {
 428                 EXOFS_ERR("_readpage => %d\n", ret);
 429                 return ret;
 430         }
 431
 432         return read_exec(&pcol, is_sync);
 433 }
 434
 435 /*
 436  * We don't need the file
 437  */
 438 static int exofs_readpage(struct file *file, struct page *page)
 439 {
 440         return _readpage(page, false);
 441 }
 442
 443 /* Callback for osd_write. All writes are asynchronouse */
 444 static void writepages_done(struct osd_request *or, void *p)
 445 {
 446         struct page_collect *pcol = p;
 447         struct bio_vec *bvec;
 448         int i;
 449         u64 resid;
 450         u64  good_bytes;
 451         u64  length = 0;
 452
 453         int ret = exofs_check_ok_resid(or, NULL, &resid);
 454
 455         osd_end_request(or);
 456         atomic_dec(&pcol->sbi->s_curr_pending);
 457
 458         if (likely(!ret))
 459                 good_bytes = pcol->length;
 460         else if (!resid)
 461                 good_bytes = 0;
 462         else
 463                 good_bytes = pcol->length - resid;
 464
 465         EXOFS_DBGMSG("writepages_done(0x%lx) good_bytes=0x%llx"
 466                      " length=0x%lx nr_pages=%u\n",
 467                      pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
 468                      pcol->nr_pages);
 469
 470         __bio_for_each_segment(bvec, pcol->bio, i, 0) {
 471                 struct page *page = bvec->bv_page;
 472                 struct inode *inode = page->mapping->host;
 473                 int page_stat;
 474
 475                 if (inode != pcol->inode)
 476                         continue; /* osd might add more pages to a bio */
 477
 478                 if (likely(length < good_bytes))
 479                         page_stat = 0;
 480                 else
 481                         page_stat = ret;
 482
 483                 update_write_page(page, page_stat);
 484                 unlock_page(page);
 485                 EXOFS_DBGMSG("    writepages_done(0x%lx, 0x%lx) status=%d\n",
 486                              inode->i_ino, page->index, page_stat);
 487
 488                 length += bvec->bv_len;
 489         }
 490
 491         pcol_free(pcol);
 492         kfree(pcol);
 493         EXOFS_DBGMSG("writepages_done END\n");
 494 }
 495
 496 static int write_exec(struct page_collect *pcol)
 497 {
 498         struct exofs_i_info *oi = exofs_i(pcol->inode);
 499         struct osd_obj_id obj = {pcol->sbi->s_pid,
 500                                         pcol->inode->i_ino + EXOFS_OBJ_OFF};
 501         struct osd_request *or = NULL;
 502         struct page_collect *pcol_copy = NULL;
 503         loff_t i_start = pcol->pg_first << PAGE_CACHE_SHIFT;
 504         int ret;
 505
 506         if (!pcol->bio)
 507                 return 0;
 508
 509         or = osd_start_request(pcol->sbi->s_dev, GFP_KERNEL);
 510         if (unlikely(!or)) {
 511                 EXOFS_ERR("write_exec: Faild to osd_start_request()\n");
 512                 ret = -ENOMEM;
 513                 goto err;
 514         }
 515
 516         pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
 517         if (!pcol_copy) {
 518                 EXOFS_ERR("write_exec: Faild to kmalloc(pcol)\n");
 519                 ret = -ENOMEM;
 520                 goto err;
 521         }
 522
 523         *pcol_copy = *pcol;
 524
 525         osd_req_write(or, &obj, pcol_copy->bio, i_start);
 526         ret = exofs_async_op(or, writepages_done, pcol_copy, oi->i_cred);
 527         if (unlikely(ret)) {
 528                 EXOFS_ERR("write_exec: exofs_async_op() Faild\n");
 529                 goto err;
 530         }
 531
 532         atomic_inc(&pcol->sbi->s_curr_pending);
 533         EXOFS_DBGMSG("write_exec(0x%lx, 0x%llx) start=0x%llx length=0x%lx\n",
 534                   pcol->inode->i_ino, pcol->pg_first, _LLU(i_start),
 535                   pcol->length);
 536         /* pages ownership was passed to pcol_copy */
 537         _pcol_reset(pcol);
 538         return 0;
 539
 540 err:
 541         _unlock_pcol_pages(pcol, ret, WRITE);
 542         kfree(pcol_copy);
 543         if (or)
 544                 osd_end_request(or);
 545         return ret;
 546 }
 547
 548 /* writepage_strip is called either directly from writepage() or by the VFS from
 549  * within write_cache_pages(), to add one more page to be written to storage.
 550  * It will try to collect as many contiguous pages as possible. If a
 551  * discontinuity is encountered or it runs out of resources it will submit the
 552  * previous segment and will start a new collection.
 553  * Eventually caller must submit the last segment if present.
 554  */
 555 static int writepage_strip(struct page *page,
 556                            struct writeback_control *wbc_unused, void *data)
 557 {
 558         struct page_collect *pcol = data;
 559         struct inode *inode = pcol->inode;
 560         struct exofs_i_info *oi = exofs_i(inode);
 561         loff_t i_size = i_size_read(inode);
 562         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 563         size_t len;
 564         int ret;
 565
 566         BUG_ON(!PageLocked(page));
 567
 568         ret = wait_obj_created(oi);
 569         if (unlikely(ret))
 570                 goto fail;
 571
 572         if (page->index < end_index)
 573                 /* in this case, the page is within the limits of the file */
 574                 len = PAGE_CACHE_SIZE;
 575         else {
 576                 len = i_size & ~PAGE_CACHE_MASK;
 577
 578                 if (page->index > end_index || !len) {
 579                         /* in this case, the page is outside the limits
 580                          * (truncate in progress)
 581                          */
 582                         ret = write_exec(pcol);
 583                         if (unlikely(ret))
 584                                 goto fail;
 585                         if (PageError(page))
 586                                 ClearPageError(page);
 587                         unlock_page(page);
 588                         return 0;
 589                 }
 590         }
 591
 592 try_again:
 593
 594         if (unlikely(pcol->pg_first == -1)) {
 595                 pcol->pg_first = page->index;
 596         } else if (unlikely((pcol->pg_first + pcol->nr_pages) !=
 597                    page->index)) {
 598                 /* Discontinuity detected, split the request */
 599                 ret = write_exec(pcol);
 600                 if (unlikely(ret))
 601                         goto fail;
 602                 goto try_again;
 603         }
 604
 605         if (!pcol->bio) {
 606                 ret = pcol_try_alloc(pcol);
 607                 if (unlikely(ret))
 608                         goto fail;
 609         }
 610
 611         EXOFS_DBGMSG("    writepage_strip(0x%lx, 0x%lx) len=0x%zx\n",
 612                      inode->i_ino, page->index, len);
 613
 614         ret = pcol_add_page(pcol, page, len);
 615         if (unlikely(ret)) {
 616                 EXOFS_DBGMSG("Failed pcol_add_page "
 617                              "nr_pages=%u total_length=0x%lx\n",
 618                              pcol->nr_pages, pcol->length);
 619
 620                 /* split the request, next loop will start again */
 621                 ret = write_exec(pcol);
 622                 if (unlikely(ret)) {
 623                         EXOFS_DBGMSG("write_exec faild => %d", ret);
 624                         goto fail;
 625                 }
 626
 627                 goto try_again;
 628         }
 629
 630         BUG_ON(PageWriteback(page));
 631         set_page_writeback(page);
 632
 633         return 0;
 634
 635 fail:
 636         set_bit(AS_EIO, &page->mapping->flags);
 637         unlock_page(page);
 638         return ret;
 639 }
 640
 641 static int exofs_writepages(struct address_space *mapping,
 642                        struct writeback_control *wbc)
 643 {
 644         struct page_collect pcol;
 645         long start, end, expected_pages;
 646         int ret;
 647
 648         start = wbc->range_start >> PAGE_CACHE_SHIFT;
 649         end = (wbc->range_end == LLONG_MAX) ?
 650                         start + mapping->nrpages :
 651                         wbc->range_end >> PAGE_CACHE_SHIFT;
 652
 653         if (start || end)
 654                 expected_pages = min(end - start + 1, 32L);
 655         else
 656                 expected_pages = mapping->nrpages;
 657
 658         EXOFS_DBGMSG("inode(0x%lx) wbc->start=0x%llx wbc->end=0x%llx"
 659                      " m->nrpages=%lu start=0x%lx end=0x%lx\n",
 660                      mapping->host->i_ino, wbc->range_start, wbc->range_end,
 661                      mapping->nrpages, start, end);
 662
 663         _pcol_init(&pcol, expected_pages, mapping->host);
 664
 665         ret = write_cache_pages(mapping, wbc, writepage_strip, &pcol);
 666         if (ret) {
 667                 EXOFS_ERR("write_cache_pages => %d\n", ret);
 668                 return ret;
 669         }
 670
 671         return write_exec(&pcol);
 672 }
 673
 674 static int exofs_writepage(struct page *page, struct writeback_control *wbc)
 675 {
 676         struct page_collect pcol;
 677         int ret;
 678
 679         _pcol_init(&pcol, 1, page->mapping->host);
 680
 681         ret = writepage_strip(page, NULL, &pcol);
 682         if (ret) {
 683                 EXOFS_ERR("exofs_writepage => %d\n", ret);
 684                 return ret;
 685         }
 686
 687         return write_exec(&pcol);
 688 }
 689
 690 int exofs_write_begin(struct file *file, struct address_space *mapping,
 691                 loff_t pos, unsigned len, unsigned flags,
 692                 struct page **pagep, void **fsdata)
 693 {
 694         int ret = 0;
 695         struct page *page;
 696
 697         page = *pagep;
 698         if (page == NULL) {
 699                 ret = simple_write_begin(file, mapping, pos, len, flags, pagep,
 700                                          fsdata);
 701                 if (ret) {
 702                         EXOFS_DBGMSG("simple_write_begin faild\n");
 703                         return ret;
 704                 }
 705
 706                 page = *pagep;
 707         }
 708
 709          /* read modify write */
 710         if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
 711                 ret = _readpage(page, true);
 712                 if (ret) {
 713                         /*SetPageError was done by _readpage. Is it ok?*/
 714                         unlock_page(page);
 715                         EXOFS_DBGMSG("__readpage_filler faild\n");
 716                 }
 717         }
 718
 719         return ret;
 720 }
 721
 722 static int exofs_write_begin_export(struct file *file,
 723                 struct address_space *mapping,
 724                 loff_t pos, unsigned len, unsigned flags,
 725                 struct page **pagep, void **fsdata)
 726 {
 727         *pagep = NULL;
 728
 729         return exofs_write_begin(file, mapping, pos, len, flags, pagep,
 730                                         fsdata);
 731 }
 732
 733 const struct address_space_operations exofs_aops = {
 734         .readpage       = exofs_readpage,
 735         .readpages      = exofs_readpages,
 736         .writepage      = exofs_writepage,
 737         .writepages     = exofs_writepages,
 738         .write_begin    = exofs_write_begin_export,
 739         .write_end      = simple_write_end,
 740 };
 741
 742 /******************************************************************************
 743  * INODE OPERATIONS
 744  *****************************************************************************/
 745
 746 /*
 747  * Test whether an inode is a fast symlink.
 748  */
 749 static inline int exofs_inode_is_fast_symlink(struct inode *inode)
 750 {
 751         struct exofs_i_info *oi = exofs_i(inode);
 752
 753         return S_ISLNK(inode->i_mode) && (oi->i_data[0] != 0);
 754 }
 755
 756 /*
 757  * get_block_t - Fill in a buffer_head
 758  * An OSD takes care of block allocation so we just fake an allocation by
 759  * putting in the inode's sector_t in the buffer_head.
 760  * TODO: What about the case of create==0 and @iblock does not exist in the
 761  * object?
 762  */
 763 static int exofs_get_block(struct inode *inode, sector_t iblock,
 764                     struct buffer_head *bh_result, int create)
 765 {
 766         map_bh(bh_result, inode->i_sb, iblock);
 767         return 0;
 768 }
 769
 770 const struct osd_attr g_attr_logical_length = ATTR_DEF(
 771         OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
 772
 773 /*
 774  * Truncate a file to the specified size - all we have to do is set the size
 775  * attribute.  We make sure the object exists first.
 776  */
 777 void exofs_truncate(struct inode *inode)
 778 {
 779         struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
 780         struct exofs_i_info *oi = exofs_i(inode);
 781         struct osd_obj_id obj = {sbi->s_pid, inode->i_ino + EXOFS_OBJ_OFF};
 782         struct osd_request *or;
 783         struct osd_attr attr;
 784         loff_t isize = i_size_read(inode);
 785         __be64 newsize;
 786         int ret;
 787
 788         if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
 789              || S_ISLNK(inode->i_mode)))
 790                 return;
 791         if (exofs_inode_is_fast_symlink(inode))
 792                 return;
 793         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
 794                 return;
 795         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 796
 797         nobh_truncate_page(inode->i_mapping, isize, exofs_get_block);
 798
 799         or = osd_start_request(sbi->s_dev, GFP_KERNEL);
 800         if (unlikely(!or)) {
 801                 EXOFS_ERR("ERROR: exofs_truncate: osd_start_request failed\n");
 802                 goto fail;
 803         }
 804
 805         osd_req_set_attributes(or, &obj);
 806
 807         newsize = cpu_to_be64((u64)isize);
 808         attr = g_attr_logical_length;
 809         attr.val_ptr = &newsize;
 810         osd_req_add_set_attr_list(or, &attr, 1);
 811
 812         /* if we are about to truncate an object, and it hasn't been
 813          * created yet, wait
 814          */
 815         if (unlikely(wait_obj_created(oi)))
 816                 goto fail;
 817
 818         ret = exofs_sync_op(or, sbi->s_timeout, oi->i_cred);
 819         osd_end_request(or);
 820         if (ret)
 821                 goto fail;
 822
 823 out:
 824         mark_inode_dirty(inode);
 825         return;
 826 fail:
 827         make_bad_inode(inode);
 828         goto out;
 829 }
 830
 831 /*
 832  * Set inode attributes - just call generic functions.
 833  */
 834 int exofs_setattr(struct dentry *dentry, struct iattr *iattr)
 835 {
 836         struct inode *inode = dentry->d_inode;
 837         int error;
 838
 839         error = inode_change_ok(inode, iattr);
 840         if (error)
 841                 return error;
 842
 843         error = inode_setattr(inode, iattr);
 844         return error;
 845 }