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