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 if (!op->store.laundering) 400 afs_pages_written_back(vnode, op->store.first, op->store.last); 401 afs_stat_v(vnode, n_stores); 402 atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) - 403 (op->store.first * PAGE_SIZE + op->store.first_offset), 404 &afs_v2net(vnode)->n_store_bytes); 405 } 406 } 407 408 static const struct afs_operation_ops afs_store_data_operation = { 409 .issue_afs_rpc = afs_fs_store_data, 410 .issue_yfs_rpc = yfs_fs_store_data, 411 .success = afs_store_data_success, 412 }; 413 414 /* 415 * write to a file 416 */ 417 static int afs_store_data(struct address_space *mapping, 418 pgoff_t first, pgoff_t last, 419 unsigned offset, unsigned to, bool laundering) 420 { 421 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 422 struct afs_operation *op; 423 struct afs_wb_key *wbk = NULL; 424 int ret; 425 426 _enter("%s{%llx:%llu.%u},%lx,%lx,%x,%x", 427 vnode->volume->name, 428 vnode->fid.vid, 429 vnode->fid.vnode, 430 vnode->fid.unique, 431 first, last, offset, to); 432 433 ret = afs_get_writeback_key(vnode, &wbk); 434 if (ret) { 435 _leave(" = %d [no keys]", ret); 436 return ret; 437 } 438 439 op = afs_alloc_operation(wbk->key, vnode->volume); 440 if (IS_ERR(op)) { 441 afs_put_wb_key(wbk); 442 return -ENOMEM; 443 } 444 445 afs_op_set_vnode(op, 0, vnode); 446 op->file[0].dv_delta = 1; 447 op->store.mapping = mapping; 448 op->store.first = first; 449 op->store.last = last; 450 op->store.first_offset = offset; 451 op->store.last_to = to; 452 op->store.laundering = laundering; 453 op->mtime = vnode->vfs_inode.i_mtime; 454 op->flags |= AFS_OPERATION_UNINTR; 455 op->ops = &afs_store_data_operation; 456 457 try_next_key: 458 afs_begin_vnode_operation(op); 459 afs_wait_for_operation(op); 460 461 switch (op->error) { 462 case -EACCES: 463 case -EPERM: 464 case -ENOKEY: 465 case -EKEYEXPIRED: 466 case -EKEYREJECTED: 467 case -EKEYREVOKED: 468 _debug("next"); 469 470 ret = afs_get_writeback_key(vnode, &wbk); 471 if (ret == 0) { 472 key_put(op->key); 473 op->key = key_get(wbk->key); 474 goto try_next_key; 475 } 476 break; 477 } 478 479 afs_put_wb_key(wbk); 480 _leave(" = %d", op->error); 481 return afs_put_operation(op); 482 } 483 484 /* 485 * Synchronously write back the locked page and any subsequent non-locked dirty 486 * pages. 487 */ 488 static int afs_write_back_from_locked_page(struct address_space *mapping, 489 struct writeback_control *wbc, 490 struct page *primary_page, 491 pgoff_t final_page) 492 { 493 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 494 struct page *pages[8], *page; 495 unsigned long count, priv; 496 unsigned n, offset, to, f, t; 497 pgoff_t start, first, last; 498 loff_t i_size, end; 499 int loop, ret; 500 501 _enter(",%lx", primary_page->index); 502 503 count = 1; 504 if (test_set_page_writeback(primary_page)) 505 BUG(); 506 507 /* Find all consecutive lockable dirty pages that have contiguous 508 * written regions, stopping when we find a page that is not 509 * immediately lockable, is not dirty or is missing, or we reach the 510 * end of the range. 511 */ 512 start = primary_page->index; 513 priv = page_private(primary_page); 514 offset = priv & AFS_PRIV_MAX; 515 to = priv >> AFS_PRIV_SHIFT; 516 trace_afs_page_dirty(vnode, tracepoint_string("store"), 517 primary_page->index, priv); 518 519 WARN_ON(offset == to); 520 if (offset == to) 521 trace_afs_page_dirty(vnode, tracepoint_string("WARN"), 522 primary_page->index, priv); 523 524 if (start >= final_page || 525 (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))) 526 goto no_more; 527 528 start++; 529 do { 530 _debug("more %lx [%lx]", start, count); 531 n = final_page - start + 1; 532 if (n > ARRAY_SIZE(pages)) 533 n = ARRAY_SIZE(pages); 534 n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages); 535 _debug("fgpc %u", n); 536 if (n == 0) 537 goto no_more; 538 if (pages[0]->index != start) { 539 do { 540 put_page(pages[--n]); 541 } while (n > 0); 542 goto no_more; 543 } 544 545 for (loop = 0; loop < n; loop++) { 546 page = pages[loop]; 547 if (to != PAGE_SIZE && 548 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) 549 break; 550 if (page->index > final_page) 551 break; 552 if (!trylock_page(page)) 553 break; 554 if (!PageDirty(page) || PageWriteback(page)) { 555 unlock_page(page); 556 break; 557 } 558 559 priv = page_private(page); 560 f = priv & AFS_PRIV_MAX; 561 t = priv >> AFS_PRIV_SHIFT; 562 if (f != 0 && 563 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) { 564 unlock_page(page); 565 break; 566 } 567 to = t; 568 569 trace_afs_page_dirty(vnode, tracepoint_string("store+"), 570 page->index, priv); 571 572 if (!clear_page_dirty_for_io(page)) 573 BUG(); 574 if (test_set_page_writeback(page)) 575 BUG(); 576 unlock_page(page); 577 put_page(page); 578 } 579 count += loop; 580 if (loop < n) { 581 for (; loop < n; loop++) 582 put_page(pages[loop]); 583 goto no_more; 584 } 585 586 start += loop; 587 } while (start <= final_page && count < 65536); 588 589 no_more: 590 /* We now have a contiguous set of dirty pages, each with writeback 591 * set; the first page is still locked at this point, but all the rest 592 * have been unlocked. 593 */ 594 unlock_page(primary_page); 595 596 first = primary_page->index; 597 last = first + count - 1; 598 599 end = (loff_t)last * PAGE_SIZE + to; 600 i_size = i_size_read(&vnode->vfs_inode); 601 602 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); 603 if (end > i_size) 604 to = i_size & ~PAGE_MASK; 605 606 ret = afs_store_data(mapping, first, last, offset, to, false); 607 switch (ret) { 608 case 0: 609 ret = count; 610 break; 611 612 default: 613 pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret); 614 fallthrough; 615 case -EACCES: 616 case -EPERM: 617 case -ENOKEY: 618 case -EKEYEXPIRED: 619 case -EKEYREJECTED: 620 case -EKEYREVOKED: 621 afs_redirty_pages(wbc, mapping, first, last); 622 mapping_set_error(mapping, ret); 623 break; 624 625 case -EDQUOT: 626 case -ENOSPC: 627 afs_redirty_pages(wbc, mapping, first, last); 628 mapping_set_error(mapping, -ENOSPC); 629 break; 630 631 case -EROFS: 632 case -EIO: 633 case -EREMOTEIO: 634 case -EFBIG: 635 case -ENOENT: 636 case -ENOMEDIUM: 637 case -ENXIO: 638 trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail); 639 afs_kill_pages(mapping, first, last); 640 mapping_set_error(mapping, ret); 641 break; 642 } 643 644 _leave(" = %d", ret); 645 return ret; 646 } 647 648 /* 649 * write a page back to the server 650 * - the caller locked the page for us 651 */ 652 int afs_writepage(struct page *page, struct writeback_control *wbc) 653 { 654 int ret; 655 656 _enter("{%lx},", page->index); 657 658 ret = afs_write_back_from_locked_page(page->mapping, wbc, page, 659 wbc->range_end >> PAGE_SHIFT); 660 if (ret < 0) { 661 _leave(" = %d", ret); 662 return 0; 663 } 664 665 wbc->nr_to_write -= ret; 666 667 _leave(" = 0"); 668 return 0; 669 } 670 671 /* 672 * write a region of pages back to the server 673 */ 674 static int afs_writepages_region(struct address_space *mapping, 675 struct writeback_control *wbc, 676 pgoff_t index, pgoff_t end, pgoff_t *_next) 677 { 678 struct page *page; 679 int ret, n; 680 681 _enter(",,%lx,%lx,", index, end); 682 683 do { 684 n = find_get_pages_range_tag(mapping, &index, end, 685 PAGECACHE_TAG_DIRTY, 1, &page); 686 if (!n) 687 break; 688 689 _debug("wback %lx", page->index); 690 691 /* 692 * at this point we hold neither the i_pages lock nor the 693 * page lock: the page may be truncated or invalidated 694 * (changing page->mapping to NULL), or even swizzled 695 * back from swapper_space to tmpfs file mapping 696 */ 697 ret = lock_page_killable(page); 698 if (ret < 0) { 699 put_page(page); 700 _leave(" = %d", ret); 701 return ret; 702 } 703 704 if (page->mapping != mapping || !PageDirty(page)) { 705 unlock_page(page); 706 put_page(page); 707 continue; 708 } 709 710 if (PageWriteback(page)) { 711 unlock_page(page); 712 if (wbc->sync_mode != WB_SYNC_NONE) 713 wait_on_page_writeback(page); 714 put_page(page); 715 continue; 716 } 717 718 if (!clear_page_dirty_for_io(page)) 719 BUG(); 720 ret = afs_write_back_from_locked_page(mapping, wbc, page, end); 721 put_page(page); 722 if (ret < 0) { 723 _leave(" = %d", ret); 724 return ret; 725 } 726 727 wbc->nr_to_write -= ret; 728 729 cond_resched(); 730 } while (index < end && wbc->nr_to_write > 0); 731 732 *_next = index; 733 _leave(" = 0 [%lx]", *_next); 734 return 0; 735 } 736 737 /* 738 * write some of the pending data back to the server 739 */ 740 int afs_writepages(struct address_space *mapping, 741 struct writeback_control *wbc) 742 { 743 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 744 pgoff_t start, end, next; 745 int ret; 746 747 _enter(""); 748 749 /* We have to be careful as we can end up racing with setattr() 750 * truncating the pagecache since the caller doesn't take a lock here 751 * to prevent it. 752 */ 753 if (wbc->sync_mode == WB_SYNC_ALL) 754 down_read(&vnode->validate_lock); 755 else if (!down_read_trylock(&vnode->validate_lock)) 756 return 0; 757 758 if (wbc->range_cyclic) { 759 start = mapping->writeback_index; 760 end = -1; 761 ret = afs_writepages_region(mapping, wbc, start, end, &next); 762 if (start > 0 && wbc->nr_to_write > 0 && ret == 0) 763 ret = afs_writepages_region(mapping, wbc, 0, start, 764 &next); 765 mapping->writeback_index = next; 766 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { 767 end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); 768 ret = afs_writepages_region(mapping, wbc, 0, end, &next); 769 if (wbc->nr_to_write > 0) 770 mapping->writeback_index = next; 771 } else { 772 start = wbc->range_start >> PAGE_SHIFT; 773 end = wbc->range_end >> PAGE_SHIFT; 774 ret = afs_writepages_region(mapping, wbc, start, end, &next); 775 } 776 777 up_read(&vnode->validate_lock); 778 _leave(" = %d", ret); 779 return ret; 780 } 781 782 /* 783 * write to an AFS file 784 */ 785 ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) 786 { 787 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); 788 ssize_t result; 789 size_t count = iov_iter_count(from); 790 791 _enter("{%llx:%llu},{%zu},", 792 vnode->fid.vid, vnode->fid.vnode, count); 793 794 if (IS_SWAPFILE(&vnode->vfs_inode)) { 795 printk(KERN_INFO 796 "AFS: Attempt to write to active swap file!\n"); 797 return -EBUSY; 798 } 799 800 if (!count) 801 return 0; 802 803 result = generic_file_write_iter(iocb, from); 804 805 _leave(" = %zd", result); 806 return result; 807 } 808 809 /* 810 * flush any dirty pages for this process, and check for write errors. 811 * - the return status from this call provides a reliable indication of 812 * whether any write errors occurred for this process. 813 */ 814 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 815 { 816 struct inode *inode = file_inode(file); 817 struct afs_vnode *vnode = AFS_FS_I(inode); 818 819 _enter("{%llx:%llu},{n=%pD},%d", 820 vnode->fid.vid, vnode->fid.vnode, file, 821 datasync); 822 823 return file_write_and_wait_range(file, start, end); 824 } 825 826 /* 827 * notification that a previously read-only page is about to become writable 828 * - if it returns an error, the caller will deliver a bus error signal 829 */ 830 vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) 831 { 832 struct file *file = vmf->vma->vm_file; 833 struct inode *inode = file_inode(file); 834 struct afs_vnode *vnode = AFS_FS_I(inode); 835 unsigned long priv; 836 837 _enter("{{%llx:%llu}},{%lx}", 838 vnode->fid.vid, vnode->fid.vnode, vmf->page->index); 839 840 sb_start_pagefault(inode->i_sb); 841 842 /* Wait for the page to be written to the cache before we allow it to 843 * be modified. We then assume the entire page will need writing back. 844 */ 845 #ifdef CONFIG_AFS_FSCACHE 846 fscache_wait_on_page_write(vnode->cache, vmf->page); 847 #endif 848 849 if (PageWriteback(vmf->page) && 850 wait_on_page_bit_killable(vmf->page, PG_writeback) < 0) 851 return VM_FAULT_RETRY; 852 853 if (lock_page_killable(vmf->page) < 0) 854 return VM_FAULT_RETRY; 855 856 /* We mustn't change page->private until writeback is complete as that 857 * details the portion of the page we need to write back and we might 858 * need to redirty the page if there's a problem. 859 */ 860 wait_on_page_writeback(vmf->page); 861 862 priv = (unsigned long)PAGE_SIZE << AFS_PRIV_SHIFT; /* To */ 863 priv |= 0; /* From */ 864 trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), 865 vmf->page->index, priv); 866 SetPagePrivate(vmf->page); 867 set_page_private(vmf->page, priv); 868 file_update_time(file); 869 870 sb_end_pagefault(inode->i_sb); 871 return VM_FAULT_LOCKED; 872 } 873 874 /* 875 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. 876 */ 877 void afs_prune_wb_keys(struct afs_vnode *vnode) 878 { 879 LIST_HEAD(graveyard); 880 struct afs_wb_key *wbk, *tmp; 881 882 /* Discard unused keys */ 883 spin_lock(&vnode->wb_lock); 884 885 if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) && 886 !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) { 887 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { 888 if (refcount_read(&wbk->usage) == 1) 889 list_move(&wbk->vnode_link, &graveyard); 890 } 891 } 892 893 spin_unlock(&vnode->wb_lock); 894 895 while (!list_empty(&graveyard)) { 896 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); 897 list_del(&wbk->vnode_link); 898 afs_put_wb_key(wbk); 899 } 900 } 901 902 /* 903 * Clean up a page during invalidation. 904 */ 905 int afs_launder_page(struct page *page) 906 { 907 struct address_space *mapping = page->mapping; 908 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 909 unsigned long priv; 910 unsigned int f, t; 911 int ret = 0; 912 913 _enter("{%lx}", page->index); 914 915 priv = page_private(page); 916 if (clear_page_dirty_for_io(page)) { 917 f = 0; 918 t = PAGE_SIZE; 919 if (PagePrivate(page)) { 920 f = priv & AFS_PRIV_MAX; 921 t = priv >> AFS_PRIV_SHIFT; 922 } 923 924 trace_afs_page_dirty(vnode, tracepoint_string("launder"), 925 page->index, priv); 926 ret = afs_store_data(mapping, page->index, page->index, t, f, true); 927 } 928 929 trace_afs_page_dirty(vnode, tracepoint_string("laundered"), 930 page->index, priv); 931 set_page_private(page, 0); 932 ClearPagePrivate(page); 933 934 #ifdef CONFIG_AFS_FSCACHE 935 if (PageFsCache(page)) { 936 fscache_wait_on_page_write(vnode->cache, page); 937 fscache_uncache_page(vnode->cache, page); 938 } 939 #endif 940 return ret; 941 } 942