1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* handling of writes to regular files and writing back to the server 3 * 4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #include <linux/backing-dev.h> 9 #include <linux/slab.h> 10 #include <linux/fs.h> 11 #include <linux/pagemap.h> 12 #include <linux/writeback.h> 13 #include <linux/pagevec.h> 14 #include "internal.h" 15 16 /* 17 * mark a page as having been made dirty and thus needing writeback 18 */ 19 int afs_set_page_dirty(struct page *page) 20 { 21 _enter(""); 22 return __set_page_dirty_nobuffers(page); 23 } 24 25 /* 26 * partly or wholly fill a page that's under preparation for writing 27 */ 28 static int afs_fill_page(struct afs_vnode *vnode, struct key *key, 29 loff_t pos, unsigned int len, struct page *page) 30 { 31 struct afs_read *req; 32 size_t p; 33 void *data; 34 int ret; 35 36 _enter(",,%llu", (unsigned long long)pos); 37 38 if (pos >= vnode->vfs_inode.i_size) { 39 p = pos & ~PAGE_MASK; 40 ASSERTCMP(p + len, <=, PAGE_SIZE); 41 data = kmap(page); 42 memset(data + p, 0, len); 43 kunmap(page); 44 return 0; 45 } 46 47 req = kzalloc(struct_size(req, array, 1), GFP_KERNEL); 48 if (!req) 49 return -ENOMEM; 50 51 refcount_set(&req->usage, 1); 52 req->pos = pos; 53 req->len = len; 54 req->nr_pages = 1; 55 req->pages = req->array; 56 req->pages[0] = page; 57 get_page(page); 58 59 ret = afs_fetch_data(vnode, key, req); 60 afs_put_read(req); 61 if (ret < 0) { 62 if (ret == -ENOENT) { 63 _debug("got NOENT from server" 64 " - marking file deleted and stale"); 65 set_bit(AFS_VNODE_DELETED, &vnode->flags); 66 ret = -ESTALE; 67 } 68 } 69 70 _leave(" = %d", ret); 71 return ret; 72 } 73 74 /* 75 * prepare to perform part of a write to a page 76 */ 77 int afs_write_begin(struct file *file, struct address_space *mapping, 78 loff_t pos, unsigned len, unsigned flags, 79 struct page **pagep, void **fsdata) 80 { 81 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 82 struct page *page; 83 struct key *key = afs_file_key(file); 84 unsigned long priv; 85 unsigned f, from = pos & (PAGE_SIZE - 1); 86 unsigned t, to = from + len; 87 pgoff_t index = pos >> PAGE_SHIFT; 88 int ret; 89 90 _enter("{%llx:%llu},{%lx},%u,%u", 91 vnode->fid.vid, vnode->fid.vnode, index, from, to); 92 93 /* We want to store information about how much of a page is altered in 94 * page->private. 95 */ 96 BUILD_BUG_ON(PAGE_SIZE > 32768 && sizeof(page->private) < 8); 97 98 page = grab_cache_page_write_begin(mapping, index, flags); 99 if (!page) 100 return -ENOMEM; 101 102 if (!PageUptodate(page) && len != PAGE_SIZE) { 103 ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page); 104 if (ret < 0) { 105 unlock_page(page); 106 put_page(page); 107 _leave(" = %d [prep]", ret); 108 return ret; 109 } 110 SetPageUptodate(page); 111 } 112 113 /* page won't leak in error case: it eventually gets cleaned off LRU */ 114 *pagep = page; 115 116 try_again: 117 /* See if this page is already partially written in a way that we can 118 * merge the new write with. 119 */ 120 t = f = 0; 121 if (PagePrivate(page)) { 122 priv = page_private(page); 123 f = priv & AFS_PRIV_MAX; 124 t = priv >> AFS_PRIV_SHIFT; 125 ASSERTCMP(f, <=, t); 126 } 127 128 if (f != t) { 129 if (PageWriteback(page)) { 130 trace_afs_page_dirty(vnode, tracepoint_string("alrdy"), 131 page->index, priv); 132 goto flush_conflicting_write; 133 } 134 /* If the file is being filled locally, allow inter-write 135 * spaces to be merged into writes. If it's not, only write 136 * back what the user gives us. 137 */ 138 if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && 139 (to < f || from > t)) 140 goto flush_conflicting_write; 141 if (from < f) 142 f = from; 143 if (to > t) 144 t = to; 145 } else { 146 f = from; 147 t = to; 148 } 149 150 priv = (unsigned long)t << AFS_PRIV_SHIFT; 151 priv |= f; 152 trace_afs_page_dirty(vnode, tracepoint_string("begin"), 153 page->index, priv); 154 SetPagePrivate(page); 155 set_page_private(page, priv); 156 _leave(" = 0"); 157 return 0; 158 159 /* The previous write and this write aren't adjacent or overlapping, so 160 * flush the page out. 161 */ 162 flush_conflicting_write: 163 _debug("flush conflict"); 164 ret = write_one_page(page); 165 if (ret < 0) { 166 _leave(" = %d", ret); 167 return ret; 168 } 169 170 ret = lock_page_killable(page); 171 if (ret < 0) { 172 _leave(" = %d", ret); 173 return ret; 174 } 175 goto try_again; 176 } 177 178 /* 179 * finalise part of a write to a page 180 */ 181 int afs_write_end(struct file *file, struct address_space *mapping, 182 loff_t pos, unsigned len, unsigned copied, 183 struct page *page, void *fsdata) 184 { 185 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 186 struct key *key = afs_file_key(file); 187 loff_t i_size, maybe_i_size; 188 int ret; 189 190 _enter("{%llx:%llu},{%lx}", 191 vnode->fid.vid, vnode->fid.vnode, page->index); 192 193 maybe_i_size = pos + copied; 194 195 i_size = i_size_read(&vnode->vfs_inode); 196 if (maybe_i_size > i_size) { 197 write_seqlock(&vnode->cb_lock); 198 i_size = i_size_read(&vnode->vfs_inode); 199 if (maybe_i_size > i_size) 200 i_size_write(&vnode->vfs_inode, maybe_i_size); 201 write_sequnlock(&vnode->cb_lock); 202 } 203 204 if (!PageUptodate(page)) { 205 if (copied < len) { 206 /* Try and load any missing data from the server. The 207 * unmarshalling routine will take care of clearing any 208 * bits that are beyond the EOF. 209 */ 210 ret = afs_fill_page(vnode, key, pos + copied, 211 len - copied, page); 212 if (ret < 0) 213 goto out; 214 } 215 SetPageUptodate(page); 216 } 217 218 set_page_dirty(page); 219 if (PageDirty(page)) 220 _debug("dirtied"); 221 ret = copied; 222 223 out: 224 unlock_page(page); 225 put_page(page); 226 return ret; 227 } 228 229 /* 230 * kill all the pages in the given range 231 */ 232 static void afs_kill_pages(struct address_space *mapping, 233 pgoff_t first, pgoff_t last) 234 { 235 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 236 struct pagevec pv; 237 unsigned count, loop; 238 239 _enter("{%llx:%llu},%lx-%lx", 240 vnode->fid.vid, vnode->fid.vnode, first, last); 241 242 pagevec_init(&pv); 243 244 do { 245 _debug("kill %lx-%lx", first, last); 246 247 count = last - first + 1; 248 if (count > PAGEVEC_SIZE) 249 count = PAGEVEC_SIZE; 250 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); 251 ASSERTCMP(pv.nr, ==, count); 252 253 for (loop = 0; loop < count; loop++) { 254 struct page *page = pv.pages[loop]; 255 ClearPageUptodate(page); 256 SetPageError(page); 257 end_page_writeback(page); 258 if (page->index >= first) 259 first = page->index + 1; 260 lock_page(page); 261 generic_error_remove_page(mapping, page); 262 unlock_page(page); 263 } 264 265 __pagevec_release(&pv); 266 } while (first <= last); 267 268 _leave(""); 269 } 270 271 /* 272 * Redirty all the pages in a given range. 273 */ 274 static void afs_redirty_pages(struct writeback_control *wbc, 275 struct address_space *mapping, 276 pgoff_t first, pgoff_t last) 277 { 278 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 279 struct pagevec pv; 280 unsigned count, loop; 281 282 _enter("{%llx:%llu},%lx-%lx", 283 vnode->fid.vid, vnode->fid.vnode, first, last); 284 285 pagevec_init(&pv); 286 287 do { 288 _debug("redirty %lx-%lx", first, last); 289 290 count = last - first + 1; 291 if (count > PAGEVEC_SIZE) 292 count = PAGEVEC_SIZE; 293 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); 294 ASSERTCMP(pv.nr, ==, count); 295 296 for (loop = 0; loop < count; loop++) { 297 struct page *page = pv.pages[loop]; 298 299 redirty_page_for_writepage(wbc, page); 300 end_page_writeback(page); 301 if (page->index >= first) 302 first = page->index + 1; 303 } 304 305 __pagevec_release(&pv); 306 } while (first <= last); 307 308 _leave(""); 309 } 310 311 /* 312 * completion of write to server 313 */ 314 static void afs_pages_written_back(struct afs_vnode *vnode, 315 pgoff_t first, pgoff_t last) 316 { 317 struct pagevec pv; 318 unsigned long priv; 319 unsigned count, loop; 320 321 _enter("{%llx:%llu},{%lx-%lx}", 322 vnode->fid.vid, vnode->fid.vnode, first, last); 323 324 pagevec_init(&pv); 325 326 do { 327 _debug("done %lx-%lx", first, last); 328 329 count = last - first + 1; 330 if (count > PAGEVEC_SIZE) 331 count = PAGEVEC_SIZE; 332 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, 333 first, count, pv.pages); 334 ASSERTCMP(pv.nr, ==, count); 335 336 for (loop = 0; loop < count; loop++) { 337 priv = page_private(pv.pages[loop]); 338 trace_afs_page_dirty(vnode, tracepoint_string("clear"), 339 pv.pages[loop]->index, priv); 340 set_page_private(pv.pages[loop], 0); 341 end_page_writeback(pv.pages[loop]); 342 } 343 first += count; 344 __pagevec_release(&pv); 345 } while (first <= last); 346 347 afs_prune_wb_keys(vnode); 348 _leave(""); 349 } 350 351 /* 352 * Find a key to use for the writeback. We cached the keys used to author the 353 * writes on the vnode. *_wbk will contain the last writeback key used or NULL 354 * and we need to start from there if it's set. 355 */ 356 static int afs_get_writeback_key(struct afs_vnode *vnode, 357 struct afs_wb_key **_wbk) 358 { 359 struct afs_wb_key *wbk = NULL; 360 struct list_head *p; 361 int ret = -ENOKEY, ret2; 362 363 spin_lock(&vnode->wb_lock); 364 if (*_wbk) 365 p = (*_wbk)->vnode_link.next; 366 else 367 p = vnode->wb_keys.next; 368 369 while (p != &vnode->wb_keys) { 370 wbk = list_entry(p, struct afs_wb_key, vnode_link); 371 _debug("wbk %u", key_serial(wbk->key)); 372 ret2 = key_validate(wbk->key); 373 if (ret2 == 0) { 374 refcount_inc(&wbk->usage); 375 _debug("USE WB KEY %u", key_serial(wbk->key)); 376 break; 377 } 378 379 wbk = NULL; 380 if (ret == -ENOKEY) 381 ret = ret2; 382 p = p->next; 383 } 384 385 spin_unlock(&vnode->wb_lock); 386 if (*_wbk) 387 afs_put_wb_key(*_wbk); 388 *_wbk = wbk; 389 return 0; 390 } 391 392 static void afs_store_data_success(struct afs_operation *op) 393 { 394 struct afs_vnode *vnode = op->file[0].vnode; 395 396 op->ctime = op->file[0].scb.status.mtime_client; 397 afs_vnode_commit_status(op, &op->file[0]); 398 if (op->error == 0) { 399 afs_pages_written_back(vnode, op->store.first, op->store.last); 400 afs_stat_v(vnode, n_stores); 401 atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) - 402 (op->store.first * PAGE_SIZE + op->store.first_offset), 403 &afs_v2net(vnode)->n_store_bytes); 404 } 405 } 406 407 static const struct afs_operation_ops afs_store_data_operation = { 408 .issue_afs_rpc = afs_fs_store_data, 409 .issue_yfs_rpc = yfs_fs_store_data, 410 .success = afs_store_data_success, 411 }; 412 413 /* 414 * write to a file 415 */ 416 static int afs_store_data(struct address_space *mapping, 417 pgoff_t first, pgoff_t last, 418 unsigned offset, unsigned to) 419 { 420 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 421 struct afs_operation *op; 422 struct afs_wb_key *wbk = NULL; 423 int ret; 424 425 _enter("%s{%llx:%llu.%u},%lx,%lx,%x,%x", 426 vnode->volume->name, 427 vnode->fid.vid, 428 vnode->fid.vnode, 429 vnode->fid.unique, 430 first, last, offset, to); 431 432 ret = afs_get_writeback_key(vnode, &wbk); 433 if (ret) { 434 _leave(" = %d [no keys]", ret); 435 return ret; 436 } 437 438 op = afs_alloc_operation(wbk->key, vnode->volume); 439 if (IS_ERR(op)) { 440 afs_put_wb_key(wbk); 441 return -ENOMEM; 442 } 443 444 afs_op_set_vnode(op, 0, vnode); 445 op->file[0].dv_delta = 1; 446 op->store.mapping = mapping; 447 op->store.first = first; 448 op->store.last = last; 449 op->store.first_offset = offset; 450 op->store.last_to = to; 451 op->mtime = vnode->vfs_inode.i_mtime; 452 op->ops = &afs_store_data_operation; 453 454 try_next_key: 455 afs_begin_vnode_operation(op); 456 afs_wait_for_operation(op); 457 458 switch (op->error) { 459 case -EACCES: 460 case -EPERM: 461 case -ENOKEY: 462 case -EKEYEXPIRED: 463 case -EKEYREJECTED: 464 case -EKEYREVOKED: 465 _debug("next"); 466 467 ret = afs_get_writeback_key(vnode, &wbk); 468 if (ret == 0) { 469 key_put(op->key); 470 op->key = key_get(wbk->key); 471 goto try_next_key; 472 } 473 break; 474 } 475 476 afs_put_wb_key(wbk); 477 _leave(" = %d", op->error); 478 return afs_put_operation(op); 479 } 480 481 /* 482 * Synchronously write back the locked page and any subsequent non-locked dirty 483 * pages. 484 */ 485 static int afs_write_back_from_locked_page(struct address_space *mapping, 486 struct writeback_control *wbc, 487 struct page *primary_page, 488 pgoff_t final_page) 489 { 490 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 491 struct page *pages[8], *page; 492 unsigned long count, priv; 493 unsigned n, offset, to, f, t; 494 pgoff_t start, first, last; 495 int loop, ret; 496 497 _enter(",%lx", primary_page->index); 498 499 count = 1; 500 if (test_set_page_writeback(primary_page)) 501 BUG(); 502 503 /* Find all consecutive lockable dirty pages that have contiguous 504 * written regions, stopping when we find a page that is not 505 * immediately lockable, is not dirty or is missing, or we reach the 506 * end of the range. 507 */ 508 start = primary_page->index; 509 priv = page_private(primary_page); 510 offset = priv & AFS_PRIV_MAX; 511 to = priv >> AFS_PRIV_SHIFT; 512 trace_afs_page_dirty(vnode, tracepoint_string("store"), 513 primary_page->index, priv); 514 515 WARN_ON(offset == to); 516 if (offset == to) 517 trace_afs_page_dirty(vnode, tracepoint_string("WARN"), 518 primary_page->index, priv); 519 520 if (start >= final_page || 521 (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))) 522 goto no_more; 523 524 start++; 525 do { 526 _debug("more %lx [%lx]", start, count); 527 n = final_page - start + 1; 528 if (n > ARRAY_SIZE(pages)) 529 n = ARRAY_SIZE(pages); 530 n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages); 531 _debug("fgpc %u", n); 532 if (n == 0) 533 goto no_more; 534 if (pages[0]->index != start) { 535 do { 536 put_page(pages[--n]); 537 } while (n > 0); 538 goto no_more; 539 } 540 541 for (loop = 0; loop < n; loop++) { 542 page = pages[loop]; 543 if (to != PAGE_SIZE && 544 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) 545 break; 546 if (page->index > final_page) 547 break; 548 if (!trylock_page(page)) 549 break; 550 if (!PageDirty(page) || PageWriteback(page)) { 551 unlock_page(page); 552 break; 553 } 554 555 priv = page_private(page); 556 f = priv & AFS_PRIV_MAX; 557 t = priv >> AFS_PRIV_SHIFT; 558 if (f != 0 && 559 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) { 560 unlock_page(page); 561 break; 562 } 563 to = t; 564 565 trace_afs_page_dirty(vnode, tracepoint_string("store+"), 566 page->index, priv); 567 568 if (!clear_page_dirty_for_io(page)) 569 BUG(); 570 if (test_set_page_writeback(page)) 571 BUG(); 572 unlock_page(page); 573 put_page(page); 574 } 575 count += loop; 576 if (loop < n) { 577 for (; loop < n; loop++) 578 put_page(pages[loop]); 579 goto no_more; 580 } 581 582 start += loop; 583 } while (start <= final_page && count < 65536); 584 585 no_more: 586 /* We now have a contiguous set of dirty pages, each with writeback 587 * set; the first page is still locked at this point, but all the rest 588 * have been unlocked. 589 */ 590 unlock_page(primary_page); 591 592 first = primary_page->index; 593 last = first + count - 1; 594 595 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); 596 597 ret = afs_store_data(mapping, first, last, offset, to); 598 switch (ret) { 599 case 0: 600 ret = count; 601 break; 602 603 default: 604 pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret); 605 /* Fall through */ 606 case -EACCES: 607 case -EPERM: 608 case -ENOKEY: 609 case -EKEYEXPIRED: 610 case -EKEYREJECTED: 611 case -EKEYREVOKED: 612 afs_redirty_pages(wbc, mapping, first, last); 613 mapping_set_error(mapping, ret); 614 break; 615 616 case -EDQUOT: 617 case -ENOSPC: 618 afs_redirty_pages(wbc, mapping, first, last); 619 mapping_set_error(mapping, -ENOSPC); 620 break; 621 622 case -EROFS: 623 case -EIO: 624 case -EREMOTEIO: 625 case -EFBIG: 626 case -ENOENT: 627 case -ENOMEDIUM: 628 case -ENXIO: 629 trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail); 630 afs_kill_pages(mapping, first, last); 631 mapping_set_error(mapping, ret); 632 break; 633 } 634 635 _leave(" = %d", ret); 636 return ret; 637 } 638 639 /* 640 * write a page back to the server 641 * - the caller locked the page for us 642 */ 643 int afs_writepage(struct page *page, struct writeback_control *wbc) 644 { 645 int ret; 646 647 _enter("{%lx},", page->index); 648 649 ret = afs_write_back_from_locked_page(page->mapping, wbc, page, 650 wbc->range_end >> PAGE_SHIFT); 651 if (ret < 0) { 652 _leave(" = %d", ret); 653 return 0; 654 } 655 656 wbc->nr_to_write -= ret; 657 658 _leave(" = 0"); 659 return 0; 660 } 661 662 /* 663 * write a region of pages back to the server 664 */ 665 static int afs_writepages_region(struct address_space *mapping, 666 struct writeback_control *wbc, 667 pgoff_t index, pgoff_t end, pgoff_t *_next) 668 { 669 struct page *page; 670 int ret, n; 671 672 _enter(",,%lx,%lx,", index, end); 673 674 do { 675 n = find_get_pages_range_tag(mapping, &index, end, 676 PAGECACHE_TAG_DIRTY, 1, &page); 677 if (!n) 678 break; 679 680 _debug("wback %lx", page->index); 681 682 /* 683 * at this point we hold neither the i_pages lock nor the 684 * page lock: the page may be truncated or invalidated 685 * (changing page->mapping to NULL), or even swizzled 686 * back from swapper_space to tmpfs file mapping 687 */ 688 ret = lock_page_killable(page); 689 if (ret < 0) { 690 put_page(page); 691 _leave(" = %d", ret); 692 return ret; 693 } 694 695 if (page->mapping != mapping || !PageDirty(page)) { 696 unlock_page(page); 697 put_page(page); 698 continue; 699 } 700 701 if (PageWriteback(page)) { 702 unlock_page(page); 703 if (wbc->sync_mode != WB_SYNC_NONE) 704 wait_on_page_writeback(page); 705 put_page(page); 706 continue; 707 } 708 709 if (!clear_page_dirty_for_io(page)) 710 BUG(); 711 ret = afs_write_back_from_locked_page(mapping, wbc, page, end); 712 put_page(page); 713 if (ret < 0) { 714 _leave(" = %d", ret); 715 return ret; 716 } 717 718 wbc->nr_to_write -= ret; 719 720 cond_resched(); 721 } while (index < end && wbc->nr_to_write > 0); 722 723 *_next = index; 724 _leave(" = 0 [%lx]", *_next); 725 return 0; 726 } 727 728 /* 729 * write some of the pending data back to the server 730 */ 731 int afs_writepages(struct address_space *mapping, 732 struct writeback_control *wbc) 733 { 734 pgoff_t start, end, next; 735 int ret; 736 737 _enter(""); 738 739 if (wbc->range_cyclic) { 740 start = mapping->writeback_index; 741 end = -1; 742 ret = afs_writepages_region(mapping, wbc, start, end, &next); 743 if (start > 0 && wbc->nr_to_write > 0 && ret == 0) 744 ret = afs_writepages_region(mapping, wbc, 0, start, 745 &next); 746 mapping->writeback_index = next; 747 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { 748 end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); 749 ret = afs_writepages_region(mapping, wbc, 0, end, &next); 750 if (wbc->nr_to_write > 0) 751 mapping->writeback_index = next; 752 } else { 753 start = wbc->range_start >> PAGE_SHIFT; 754 end = wbc->range_end >> PAGE_SHIFT; 755 ret = afs_writepages_region(mapping, wbc, start, end, &next); 756 } 757 758 _leave(" = %d", ret); 759 return ret; 760 } 761 762 /* 763 * write to an AFS file 764 */ 765 ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) 766 { 767 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); 768 ssize_t result; 769 size_t count = iov_iter_count(from); 770 771 _enter("{%llx:%llu},{%zu},", 772 vnode->fid.vid, vnode->fid.vnode, count); 773 774 if (IS_SWAPFILE(&vnode->vfs_inode)) { 775 printk(KERN_INFO 776 "AFS: Attempt to write to active swap file!\n"); 777 return -EBUSY; 778 } 779 780 if (!count) 781 return 0; 782 783 result = generic_file_write_iter(iocb, from); 784 785 _leave(" = %zd", result); 786 return result; 787 } 788 789 /* 790 * flush any dirty pages for this process, and check for write errors. 791 * - the return status from this call provides a reliable indication of 792 * whether any write errors occurred for this process. 793 */ 794 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 795 { 796 struct inode *inode = file_inode(file); 797 struct afs_vnode *vnode = AFS_FS_I(inode); 798 799 _enter("{%llx:%llu},{n=%pD},%d", 800 vnode->fid.vid, vnode->fid.vnode, file, 801 datasync); 802 803 return file_write_and_wait_range(file, start, end); 804 } 805 806 /* 807 * notification that a previously read-only page is about to become writable 808 * - if it returns an error, the caller will deliver a bus error signal 809 */ 810 vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) 811 { 812 struct file *file = vmf->vma->vm_file; 813 struct inode *inode = file_inode(file); 814 struct afs_vnode *vnode = AFS_FS_I(inode); 815 unsigned long priv; 816 817 _enter("{{%llx:%llu}},{%lx}", 818 vnode->fid.vid, vnode->fid.vnode, vmf->page->index); 819 820 sb_start_pagefault(inode->i_sb); 821 822 /* Wait for the page to be written to the cache before we allow it to 823 * be modified. We then assume the entire page will need writing back. 824 */ 825 #ifdef CONFIG_AFS_FSCACHE 826 fscache_wait_on_page_write(vnode->cache, vmf->page); 827 #endif 828 829 if (PageWriteback(vmf->page) && 830 wait_on_page_bit_killable(vmf->page, PG_writeback) < 0) 831 return VM_FAULT_RETRY; 832 833 if (lock_page_killable(vmf->page) < 0) 834 return VM_FAULT_RETRY; 835 836 /* We mustn't change page->private until writeback is complete as that 837 * details the portion of the page we need to write back and we might 838 * need to redirty the page if there's a problem. 839 */ 840 wait_on_page_writeback(vmf->page); 841 842 priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */ 843 priv |= 0; /* From */ 844 trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), 845 vmf->page->index, priv); 846 SetPagePrivate(vmf->page); 847 set_page_private(vmf->page, priv); 848 file_update_time(file); 849 850 sb_end_pagefault(inode->i_sb); 851 return VM_FAULT_LOCKED; 852 } 853 854 /* 855 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. 856 */ 857 void afs_prune_wb_keys(struct afs_vnode *vnode) 858 { 859 LIST_HEAD(graveyard); 860 struct afs_wb_key *wbk, *tmp; 861 862 /* Discard unused keys */ 863 spin_lock(&vnode->wb_lock); 864 865 if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) && 866 !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) { 867 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { 868 if (refcount_read(&wbk->usage) == 1) 869 list_move(&wbk->vnode_link, &graveyard); 870 } 871 } 872 873 spin_unlock(&vnode->wb_lock); 874 875 while (!list_empty(&graveyard)) { 876 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); 877 list_del(&wbk->vnode_link); 878 afs_put_wb_key(wbk); 879 } 880 } 881 882 /* 883 * Clean up a page during invalidation. 884 */ 885 int afs_launder_page(struct page *page) 886 { 887 struct address_space *mapping = page->mapping; 888 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 889 unsigned long priv; 890 unsigned int f, t; 891 int ret = 0; 892 893 _enter("{%lx}", page->index); 894 895 priv = page_private(page); 896 if (clear_page_dirty_for_io(page)) { 897 f = 0; 898 t = PAGE_SIZE; 899 if (PagePrivate(page)) { 900 f = priv & AFS_PRIV_MAX; 901 t = priv >> AFS_PRIV_SHIFT; 902 } 903 904 trace_afs_page_dirty(vnode, tracepoint_string("launder"), 905 page->index, priv); 906 ret = afs_store_data(mapping, page->index, page->index, t, f); 907 } 908 909 trace_afs_page_dirty(vnode, tracepoint_string("laundered"), 910 page->index, priv); 911 set_page_private(page, 0); 912 ClearPagePrivate(page); 913 914 #ifdef CONFIG_AFS_FSCACHE 915 if (PageFsCache(page)) { 916 fscache_wait_on_page_write(vnode->cache, page); 917 fscache_uncache_page(vnode->cache, page); 918 } 919 #endif 920 return ret; 921 } 922