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 **_page, 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 try_again: 114 /* See if this page is already partially written in a way that we can 115 * merge the new write with. 116 */ 117 t = f = 0; 118 if (PagePrivate(page)) { 119 priv = page_private(page); 120 f = priv & AFS_PRIV_MAX; 121 t = priv >> AFS_PRIV_SHIFT; 122 ASSERTCMP(f, <=, t); 123 } 124 125 if (f != t) { 126 if (PageWriteback(page)) { 127 trace_afs_page_dirty(vnode, tracepoint_string("alrdy"), 128 page->index, priv); 129 goto flush_conflicting_write; 130 } 131 /* If the file is being filled locally, allow inter-write 132 * spaces to be merged into writes. If it's not, only write 133 * back what the user gives us. 134 */ 135 if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && 136 (to < f || from > t)) 137 goto flush_conflicting_write; 138 } 139 140 *_page = page; 141 _leave(" = 0"); 142 return 0; 143 144 /* The previous write and this write aren't adjacent or overlapping, so 145 * flush the page out. 146 */ 147 flush_conflicting_write: 148 _debug("flush conflict"); 149 ret = write_one_page(page); 150 if (ret < 0) 151 goto error; 152 153 ret = lock_page_killable(page); 154 if (ret < 0) 155 goto error; 156 goto try_again; 157 158 error: 159 put_page(page); 160 _leave(" = %d", ret); 161 return ret; 162 } 163 164 /* 165 * finalise part of a write to a page 166 */ 167 int afs_write_end(struct file *file, struct address_space *mapping, 168 loff_t pos, unsigned len, unsigned copied, 169 struct page *page, void *fsdata) 170 { 171 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 172 struct key *key = afs_file_key(file); 173 unsigned long priv; 174 unsigned int f, from = pos & (PAGE_SIZE - 1); 175 unsigned int t, to = from + copied; 176 loff_t i_size, maybe_i_size; 177 int ret; 178 179 _enter("{%llx:%llu},{%lx}", 180 vnode->fid.vid, vnode->fid.vnode, page->index); 181 182 maybe_i_size = pos + copied; 183 184 i_size = i_size_read(&vnode->vfs_inode); 185 if (maybe_i_size > i_size) { 186 write_seqlock(&vnode->cb_lock); 187 i_size = i_size_read(&vnode->vfs_inode); 188 if (maybe_i_size > i_size) 189 i_size_write(&vnode->vfs_inode, maybe_i_size); 190 write_sequnlock(&vnode->cb_lock); 191 } 192 193 if (!PageUptodate(page)) { 194 if (copied < len) { 195 /* Try and load any missing data from the server. The 196 * unmarshalling routine will take care of clearing any 197 * bits that are beyond the EOF. 198 */ 199 ret = afs_fill_page(vnode, key, pos + copied, 200 len - copied, page); 201 if (ret < 0) 202 goto out; 203 } 204 SetPageUptodate(page); 205 } 206 207 if (PagePrivate(page)) { 208 priv = page_private(page); 209 f = priv & AFS_PRIV_MAX; 210 t = priv >> AFS_PRIV_SHIFT; 211 if (from < f) 212 f = from; 213 if (to > t) 214 t = to; 215 priv = (unsigned long)t << AFS_PRIV_SHIFT; 216 priv |= f; 217 set_page_private(page, priv); 218 trace_afs_page_dirty(vnode, tracepoint_string("dirty+"), 219 page->index, priv); 220 } else { 221 f = from; 222 t = to; 223 priv = (unsigned long)t << AFS_PRIV_SHIFT; 224 priv |= f; 225 attach_page_private(page, (void *)priv); 226 trace_afs_page_dirty(vnode, tracepoint_string("dirty"), 227 page->index, priv); 228 } 229 230 set_page_dirty(page); 231 if (PageDirty(page)) 232 _debug("dirtied"); 233 ret = copied; 234 235 out: 236 unlock_page(page); 237 put_page(page); 238 return ret; 239 } 240 241 /* 242 * kill all the pages in the given range 243 */ 244 static void afs_kill_pages(struct address_space *mapping, 245 pgoff_t first, pgoff_t last) 246 { 247 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 248 struct pagevec pv; 249 unsigned count, loop; 250 251 _enter("{%llx:%llu},%lx-%lx", 252 vnode->fid.vid, vnode->fid.vnode, first, last); 253 254 pagevec_init(&pv); 255 256 do { 257 _debug("kill %lx-%lx", first, last); 258 259 count = last - first + 1; 260 if (count > PAGEVEC_SIZE) 261 count = PAGEVEC_SIZE; 262 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); 263 ASSERTCMP(pv.nr, ==, count); 264 265 for (loop = 0; loop < count; loop++) { 266 struct page *page = pv.pages[loop]; 267 ClearPageUptodate(page); 268 SetPageError(page); 269 end_page_writeback(page); 270 if (page->index >= first) 271 first = page->index + 1; 272 lock_page(page); 273 generic_error_remove_page(mapping, page); 274 unlock_page(page); 275 } 276 277 __pagevec_release(&pv); 278 } while (first <= last); 279 280 _leave(""); 281 } 282 283 /* 284 * Redirty all the pages in a given range. 285 */ 286 static void afs_redirty_pages(struct writeback_control *wbc, 287 struct address_space *mapping, 288 pgoff_t first, pgoff_t last) 289 { 290 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 291 struct pagevec pv; 292 unsigned count, loop; 293 294 _enter("{%llx:%llu},%lx-%lx", 295 vnode->fid.vid, vnode->fid.vnode, first, last); 296 297 pagevec_init(&pv); 298 299 do { 300 _debug("redirty %lx-%lx", first, last); 301 302 count = last - first + 1; 303 if (count > PAGEVEC_SIZE) 304 count = PAGEVEC_SIZE; 305 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); 306 ASSERTCMP(pv.nr, ==, count); 307 308 for (loop = 0; loop < count; loop++) { 309 struct page *page = pv.pages[loop]; 310 311 redirty_page_for_writepage(wbc, page); 312 end_page_writeback(page); 313 if (page->index >= first) 314 first = page->index + 1; 315 } 316 317 __pagevec_release(&pv); 318 } while (first <= last); 319 320 _leave(""); 321 } 322 323 /* 324 * completion of write to server 325 */ 326 static void afs_pages_written_back(struct afs_vnode *vnode, 327 pgoff_t first, pgoff_t last) 328 { 329 struct pagevec pv; 330 unsigned long priv; 331 unsigned count, loop; 332 333 _enter("{%llx:%llu},{%lx-%lx}", 334 vnode->fid.vid, vnode->fid.vnode, first, last); 335 336 pagevec_init(&pv); 337 338 do { 339 _debug("done %lx-%lx", first, last); 340 341 count = last - first + 1; 342 if (count > PAGEVEC_SIZE) 343 count = PAGEVEC_SIZE; 344 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, 345 first, count, pv.pages); 346 ASSERTCMP(pv.nr, ==, count); 347 348 for (loop = 0; loop < count; loop++) { 349 priv = (unsigned long)detach_page_private(pv.pages[loop]); 350 trace_afs_page_dirty(vnode, tracepoint_string("clear"), 351 pv.pages[loop]->index, priv); 352 end_page_writeback(pv.pages[loop]); 353 } 354 first += count; 355 __pagevec_release(&pv); 356 } while (first <= last); 357 358 afs_prune_wb_keys(vnode); 359 _leave(""); 360 } 361 362 /* 363 * Find a key to use for the writeback. We cached the keys used to author the 364 * writes on the vnode. *_wbk will contain the last writeback key used or NULL 365 * and we need to start from there if it's set. 366 */ 367 static int afs_get_writeback_key(struct afs_vnode *vnode, 368 struct afs_wb_key **_wbk) 369 { 370 struct afs_wb_key *wbk = NULL; 371 struct list_head *p; 372 int ret = -ENOKEY, ret2; 373 374 spin_lock(&vnode->wb_lock); 375 if (*_wbk) 376 p = (*_wbk)->vnode_link.next; 377 else 378 p = vnode->wb_keys.next; 379 380 while (p != &vnode->wb_keys) { 381 wbk = list_entry(p, struct afs_wb_key, vnode_link); 382 _debug("wbk %u", key_serial(wbk->key)); 383 ret2 = key_validate(wbk->key); 384 if (ret2 == 0) { 385 refcount_inc(&wbk->usage); 386 _debug("USE WB KEY %u", key_serial(wbk->key)); 387 break; 388 } 389 390 wbk = NULL; 391 if (ret == -ENOKEY) 392 ret = ret2; 393 p = p->next; 394 } 395 396 spin_unlock(&vnode->wb_lock); 397 if (*_wbk) 398 afs_put_wb_key(*_wbk); 399 *_wbk = wbk; 400 return 0; 401 } 402 403 static void afs_store_data_success(struct afs_operation *op) 404 { 405 struct afs_vnode *vnode = op->file[0].vnode; 406 407 op->ctime = op->file[0].scb.status.mtime_client; 408 afs_vnode_commit_status(op, &op->file[0]); 409 if (op->error == 0) { 410 if (!op->store.laundering) 411 afs_pages_written_back(vnode, op->store.first, op->store.last); 412 afs_stat_v(vnode, n_stores); 413 atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) - 414 (op->store.first * PAGE_SIZE + op->store.first_offset), 415 &afs_v2net(vnode)->n_store_bytes); 416 } 417 } 418 419 static const struct afs_operation_ops afs_store_data_operation = { 420 .issue_afs_rpc = afs_fs_store_data, 421 .issue_yfs_rpc = yfs_fs_store_data, 422 .success = afs_store_data_success, 423 }; 424 425 /* 426 * write to a file 427 */ 428 static int afs_store_data(struct address_space *mapping, 429 pgoff_t first, pgoff_t last, 430 unsigned offset, unsigned to, bool laundering) 431 { 432 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 433 struct afs_operation *op; 434 struct afs_wb_key *wbk = NULL; 435 int ret; 436 437 _enter("%s{%llx:%llu.%u},%lx,%lx,%x,%x", 438 vnode->volume->name, 439 vnode->fid.vid, 440 vnode->fid.vnode, 441 vnode->fid.unique, 442 first, last, offset, to); 443 444 ret = afs_get_writeback_key(vnode, &wbk); 445 if (ret) { 446 _leave(" = %d [no keys]", ret); 447 return ret; 448 } 449 450 op = afs_alloc_operation(wbk->key, vnode->volume); 451 if (IS_ERR(op)) { 452 afs_put_wb_key(wbk); 453 return -ENOMEM; 454 } 455 456 afs_op_set_vnode(op, 0, vnode); 457 op->file[0].dv_delta = 1; 458 op->store.mapping = mapping; 459 op->store.first = first; 460 op->store.last = last; 461 op->store.first_offset = offset; 462 op->store.last_to = to; 463 op->store.laundering = laundering; 464 op->mtime = vnode->vfs_inode.i_mtime; 465 op->flags |= AFS_OPERATION_UNINTR; 466 op->ops = &afs_store_data_operation; 467 468 try_next_key: 469 afs_begin_vnode_operation(op); 470 afs_wait_for_operation(op); 471 472 switch (op->error) { 473 case -EACCES: 474 case -EPERM: 475 case -ENOKEY: 476 case -EKEYEXPIRED: 477 case -EKEYREJECTED: 478 case -EKEYREVOKED: 479 _debug("next"); 480 481 ret = afs_get_writeback_key(vnode, &wbk); 482 if (ret == 0) { 483 key_put(op->key); 484 op->key = key_get(wbk->key); 485 goto try_next_key; 486 } 487 break; 488 } 489 490 afs_put_wb_key(wbk); 491 _leave(" = %d", op->error); 492 return afs_put_operation(op); 493 } 494 495 /* 496 * Synchronously write back the locked page and any subsequent non-locked dirty 497 * pages. 498 */ 499 static int afs_write_back_from_locked_page(struct address_space *mapping, 500 struct writeback_control *wbc, 501 struct page *primary_page, 502 pgoff_t final_page) 503 { 504 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 505 struct page *pages[8], *page; 506 unsigned long count, priv; 507 unsigned n, offset, to, f, t; 508 pgoff_t start, first, last; 509 loff_t i_size, end; 510 int loop, ret; 511 512 _enter(",%lx", primary_page->index); 513 514 count = 1; 515 if (test_set_page_writeback(primary_page)) 516 BUG(); 517 518 /* Find all consecutive lockable dirty pages that have contiguous 519 * written regions, stopping when we find a page that is not 520 * immediately lockable, is not dirty or is missing, or we reach the 521 * end of the range. 522 */ 523 start = primary_page->index; 524 priv = page_private(primary_page); 525 offset = priv & AFS_PRIV_MAX; 526 to = priv >> AFS_PRIV_SHIFT; 527 trace_afs_page_dirty(vnode, tracepoint_string("store"), 528 primary_page->index, priv); 529 530 WARN_ON(offset == to); 531 if (offset == to) 532 trace_afs_page_dirty(vnode, tracepoint_string("WARN"), 533 primary_page->index, priv); 534 535 if (start >= final_page || 536 (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))) 537 goto no_more; 538 539 start++; 540 do { 541 _debug("more %lx [%lx]", start, count); 542 n = final_page - start + 1; 543 if (n > ARRAY_SIZE(pages)) 544 n = ARRAY_SIZE(pages); 545 n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages); 546 _debug("fgpc %u", n); 547 if (n == 0) 548 goto no_more; 549 if (pages[0]->index != start) { 550 do { 551 put_page(pages[--n]); 552 } while (n > 0); 553 goto no_more; 554 } 555 556 for (loop = 0; loop < n; loop++) { 557 page = pages[loop]; 558 if (to != PAGE_SIZE && 559 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) 560 break; 561 if (page->index > final_page) 562 break; 563 if (!trylock_page(page)) 564 break; 565 if (!PageDirty(page) || PageWriteback(page)) { 566 unlock_page(page); 567 break; 568 } 569 570 priv = page_private(page); 571 f = priv & AFS_PRIV_MAX; 572 t = priv >> AFS_PRIV_SHIFT; 573 if (f != 0 && 574 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) { 575 unlock_page(page); 576 break; 577 } 578 to = t; 579 580 trace_afs_page_dirty(vnode, tracepoint_string("store+"), 581 page->index, priv); 582 583 if (!clear_page_dirty_for_io(page)) 584 BUG(); 585 if (test_set_page_writeback(page)) 586 BUG(); 587 unlock_page(page); 588 put_page(page); 589 } 590 count += loop; 591 if (loop < n) { 592 for (; loop < n; loop++) 593 put_page(pages[loop]); 594 goto no_more; 595 } 596 597 start += loop; 598 } while (start <= final_page && count < 65536); 599 600 no_more: 601 /* We now have a contiguous set of dirty pages, each with writeback 602 * set; the first page is still locked at this point, but all the rest 603 * have been unlocked. 604 */ 605 unlock_page(primary_page); 606 607 first = primary_page->index; 608 last = first + count - 1; 609 610 end = (loff_t)last * PAGE_SIZE + to; 611 i_size = i_size_read(&vnode->vfs_inode); 612 613 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); 614 if (end > i_size) 615 to = i_size & ~PAGE_MASK; 616 617 ret = afs_store_data(mapping, first, last, offset, to, false); 618 switch (ret) { 619 case 0: 620 ret = count; 621 break; 622 623 default: 624 pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret); 625 fallthrough; 626 case -EACCES: 627 case -EPERM: 628 case -ENOKEY: 629 case -EKEYEXPIRED: 630 case -EKEYREJECTED: 631 case -EKEYREVOKED: 632 afs_redirty_pages(wbc, mapping, first, last); 633 mapping_set_error(mapping, ret); 634 break; 635 636 case -EDQUOT: 637 case -ENOSPC: 638 afs_redirty_pages(wbc, mapping, first, last); 639 mapping_set_error(mapping, -ENOSPC); 640 break; 641 642 case -EROFS: 643 case -EIO: 644 case -EREMOTEIO: 645 case -EFBIG: 646 case -ENOENT: 647 case -ENOMEDIUM: 648 case -ENXIO: 649 trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail); 650 afs_kill_pages(mapping, first, last); 651 mapping_set_error(mapping, ret); 652 break; 653 } 654 655 _leave(" = %d", ret); 656 return ret; 657 } 658 659 /* 660 * write a page back to the server 661 * - the caller locked the page for us 662 */ 663 int afs_writepage(struct page *page, struct writeback_control *wbc) 664 { 665 int ret; 666 667 _enter("{%lx},", page->index); 668 669 ret = afs_write_back_from_locked_page(page->mapping, wbc, page, 670 wbc->range_end >> PAGE_SHIFT); 671 if (ret < 0) { 672 _leave(" = %d", ret); 673 return 0; 674 } 675 676 wbc->nr_to_write -= ret; 677 678 _leave(" = 0"); 679 return 0; 680 } 681 682 /* 683 * write a region of pages back to the server 684 */ 685 static int afs_writepages_region(struct address_space *mapping, 686 struct writeback_control *wbc, 687 pgoff_t index, pgoff_t end, pgoff_t *_next) 688 { 689 struct page *page; 690 int ret, n; 691 692 _enter(",,%lx,%lx,", index, end); 693 694 do { 695 n = find_get_pages_range_tag(mapping, &index, end, 696 PAGECACHE_TAG_DIRTY, 1, &page); 697 if (!n) 698 break; 699 700 _debug("wback %lx", page->index); 701 702 /* 703 * at this point we hold neither the i_pages lock nor the 704 * page lock: the page may be truncated or invalidated 705 * (changing page->mapping to NULL), or even swizzled 706 * back from swapper_space to tmpfs file mapping 707 */ 708 ret = lock_page_killable(page); 709 if (ret < 0) { 710 put_page(page); 711 _leave(" = %d", ret); 712 return ret; 713 } 714 715 if (page->mapping != mapping || !PageDirty(page)) { 716 unlock_page(page); 717 put_page(page); 718 continue; 719 } 720 721 if (PageWriteback(page)) { 722 unlock_page(page); 723 if (wbc->sync_mode != WB_SYNC_NONE) 724 wait_on_page_writeback(page); 725 put_page(page); 726 continue; 727 } 728 729 if (!clear_page_dirty_for_io(page)) 730 BUG(); 731 ret = afs_write_back_from_locked_page(mapping, wbc, page, end); 732 put_page(page); 733 if (ret < 0) { 734 _leave(" = %d", ret); 735 return ret; 736 } 737 738 wbc->nr_to_write -= ret; 739 740 cond_resched(); 741 } while (index < end && wbc->nr_to_write > 0); 742 743 *_next = index; 744 _leave(" = 0 [%lx]", *_next); 745 return 0; 746 } 747 748 /* 749 * write some of the pending data back to the server 750 */ 751 int afs_writepages(struct address_space *mapping, 752 struct writeback_control *wbc) 753 { 754 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 755 pgoff_t start, end, next; 756 int ret; 757 758 _enter(""); 759 760 /* We have to be careful as we can end up racing with setattr() 761 * truncating the pagecache since the caller doesn't take a lock here 762 * to prevent it. 763 */ 764 if (wbc->sync_mode == WB_SYNC_ALL) 765 down_read(&vnode->validate_lock); 766 else if (!down_read_trylock(&vnode->validate_lock)) 767 return 0; 768 769 if (wbc->range_cyclic) { 770 start = mapping->writeback_index; 771 end = -1; 772 ret = afs_writepages_region(mapping, wbc, start, end, &next); 773 if (start > 0 && wbc->nr_to_write > 0 && ret == 0) 774 ret = afs_writepages_region(mapping, wbc, 0, start, 775 &next); 776 mapping->writeback_index = next; 777 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { 778 end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); 779 ret = afs_writepages_region(mapping, wbc, 0, end, &next); 780 if (wbc->nr_to_write > 0) 781 mapping->writeback_index = next; 782 } else { 783 start = wbc->range_start >> PAGE_SHIFT; 784 end = wbc->range_end >> PAGE_SHIFT; 785 ret = afs_writepages_region(mapping, wbc, start, end, &next); 786 } 787 788 up_read(&vnode->validate_lock); 789 _leave(" = %d", ret); 790 return ret; 791 } 792 793 /* 794 * write to an AFS file 795 */ 796 ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) 797 { 798 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); 799 ssize_t result; 800 size_t count = iov_iter_count(from); 801 802 _enter("{%llx:%llu},{%zu},", 803 vnode->fid.vid, vnode->fid.vnode, count); 804 805 if (IS_SWAPFILE(&vnode->vfs_inode)) { 806 printk(KERN_INFO 807 "AFS: Attempt to write to active swap file!\n"); 808 return -EBUSY; 809 } 810 811 if (!count) 812 return 0; 813 814 result = generic_file_write_iter(iocb, from); 815 816 _leave(" = %zd", result); 817 return result; 818 } 819 820 /* 821 * flush any dirty pages for this process, and check for write errors. 822 * - the return status from this call provides a reliable indication of 823 * whether any write errors occurred for this process. 824 */ 825 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 826 { 827 struct inode *inode = file_inode(file); 828 struct afs_vnode *vnode = AFS_FS_I(inode); 829 830 _enter("{%llx:%llu},{n=%pD},%d", 831 vnode->fid.vid, vnode->fid.vnode, file, 832 datasync); 833 834 return file_write_and_wait_range(file, start, end); 835 } 836 837 /* 838 * notification that a previously read-only page is about to become writable 839 * - if it returns an error, the caller will deliver a bus error signal 840 */ 841 vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) 842 { 843 struct file *file = vmf->vma->vm_file; 844 struct inode *inode = file_inode(file); 845 struct afs_vnode *vnode = AFS_FS_I(inode); 846 unsigned long priv; 847 848 _enter("{{%llx:%llu}},{%lx}", 849 vnode->fid.vid, vnode->fid.vnode, vmf->page->index); 850 851 sb_start_pagefault(inode->i_sb); 852 853 /* Wait for the page to be written to the cache before we allow it to 854 * be modified. We then assume the entire page will need writing back. 855 */ 856 #ifdef CONFIG_AFS_FSCACHE 857 fscache_wait_on_page_write(vnode->cache, vmf->page); 858 #endif 859 860 if (PageWriteback(vmf->page) && 861 wait_on_page_bit_killable(vmf->page, PG_writeback) < 0) 862 return VM_FAULT_RETRY; 863 864 if (lock_page_killable(vmf->page) < 0) 865 return VM_FAULT_RETRY; 866 867 /* We mustn't change page->private until writeback is complete as that 868 * details the portion of the page we need to write back and we might 869 * need to redirty the page if there's a problem. 870 */ 871 wait_on_page_writeback(vmf->page); 872 873 priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */ 874 priv |= 0; /* From */ 875 trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), 876 vmf->page->index, priv); 877 if (PagePrivate(vmf->page)) 878 set_page_private(vmf->page, priv); 879 else 880 attach_page_private(vmf->page, (void *)priv); 881 file_update_time(file); 882 883 sb_end_pagefault(inode->i_sb); 884 return VM_FAULT_LOCKED; 885 } 886 887 /* 888 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. 889 */ 890 void afs_prune_wb_keys(struct afs_vnode *vnode) 891 { 892 LIST_HEAD(graveyard); 893 struct afs_wb_key *wbk, *tmp; 894 895 /* Discard unused keys */ 896 spin_lock(&vnode->wb_lock); 897 898 if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) && 899 !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) { 900 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { 901 if (refcount_read(&wbk->usage) == 1) 902 list_move(&wbk->vnode_link, &graveyard); 903 } 904 } 905 906 spin_unlock(&vnode->wb_lock); 907 908 while (!list_empty(&graveyard)) { 909 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); 910 list_del(&wbk->vnode_link); 911 afs_put_wb_key(wbk); 912 } 913 } 914 915 /* 916 * Clean up a page during invalidation. 917 */ 918 int afs_launder_page(struct page *page) 919 { 920 struct address_space *mapping = page->mapping; 921 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 922 unsigned long priv; 923 unsigned int f, t; 924 int ret = 0; 925 926 _enter("{%lx}", page->index); 927 928 priv = page_private(page); 929 if (clear_page_dirty_for_io(page)) { 930 f = 0; 931 t = PAGE_SIZE; 932 if (PagePrivate(page)) { 933 f = priv & AFS_PRIV_MAX; 934 t = priv >> AFS_PRIV_SHIFT; 935 } 936 937 trace_afs_page_dirty(vnode, tracepoint_string("launder"), 938 page->index, priv); 939 ret = afs_store_data(mapping, page->index, page->index, t, f, true); 940 } 941 942 priv = (unsigned long)detach_page_private(page); 943 trace_afs_page_dirty(vnode, tracepoint_string("laundered"), 944 page->index, priv); 945 946 #ifdef CONFIG_AFS_FSCACHE 947 if (PageFsCache(page)) { 948 fscache_wait_on_page_write(vnode->cache, page); 949 fscache_uncache_page(vnode->cache, page); 950 } 951 #endif 952 return ret; 953 } 954