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 */ 19int 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 */ 28static 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 */ 77int 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 page = grab_cache_page_write_begin(mapping, index, flags); 94 if (!page) 95 return -ENOMEM; 96 97 if (!PageUptodate(page) && len != PAGE_SIZE) { 98 ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page); 99 if (ret < 0) { 100 unlock_page(page); 101 put_page(page); 102 _leave(" = %d [prep]", ret); 103 return ret; 104 } 105 SetPageUptodate(page); 106 } 107 108try_again: 109 /* See if this page is already partially written in a way that we can 110 * merge the new write with. 111 */ 112 t = f = 0; 113 if (PagePrivate(page)) { 114 priv = page_private(page); 115 f = afs_page_dirty_from(priv); 116 t = afs_page_dirty_to(priv); 117 ASSERTCMP(f, <=, t); 118 } 119 120 if (f != t) { 121 if (PageWriteback(page)) { 122 trace_afs_page_dirty(vnode, tracepoint_string("alrdy"), 123 page->index, priv); 124 goto flush_conflicting_write; 125 } 126 /* If the file is being filled locally, allow inter-write 127 * spaces to be merged into writes. If it's not, only write 128 * back what the user gives us. 129 */ 130 if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && 131 (to < f || from > t)) 132 goto flush_conflicting_write; 133 } 134 135 *_page = page; 136 _leave(" = 0"); 137 return 0; 138 139 /* The previous write and this write aren't adjacent or overlapping, so 140 * flush the page out. 141 */ 142flush_conflicting_write: 143 _debug("flush conflict"); 144 ret = write_one_page(page); 145 if (ret < 0) 146 goto error; 147 148 ret = lock_page_killable(page); 149 if (ret < 0) 150 goto error; 151 goto try_again; 152 153error: 154 put_page(page); 155 _leave(" = %d", ret); 156 return ret; 157} 158 159/* 160 * finalise part of a write to a page 161 */ 162int afs_write_end(struct file *file, struct address_space *mapping, 163 loff_t pos, unsigned len, unsigned copied, 164 struct page *page, void *fsdata) 165{ 166 struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); 167 struct key *key = afs_file_key(file); 168 unsigned long priv; 169 unsigned int f, from = pos & (PAGE_SIZE - 1); 170 unsigned int t, to = from + copied; 171 loff_t i_size, maybe_i_size; 172 int ret = 0; 173 174 _enter("{%llx:%llu},{%lx}", 175 vnode->fid.vid, vnode->fid.vnode, page->index); 176 177 if (copied == 0) 178 goto out; 179 180 maybe_i_size = pos + copied; 181 182 i_size = i_size_read(&vnode->vfs_inode); 183 if (maybe_i_size > i_size) { 184 write_seqlock(&vnode->cb_lock); 185 i_size = i_size_read(&vnode->vfs_inode); 186 if (maybe_i_size > i_size) 187 afs_set_i_size(vnode, maybe_i_size); 188 write_sequnlock(&vnode->cb_lock); 189 } 190 191 if (!PageUptodate(page)) { 192 if (copied < len) { 193 /* Try and load any missing data from the server. The 194 * unmarshalling routine will take care of clearing any 195 * bits that are beyond the EOF. 196 */ 197 ret = afs_fill_page(vnode, key, pos + copied, 198 len - copied, page); 199 if (ret < 0) 200 goto out; 201 } 202 SetPageUptodate(page); 203 } 204 205 if (PagePrivate(page)) { 206 priv = page_private(page); 207 f = afs_page_dirty_from(priv); 208 t = afs_page_dirty_to(priv); 209 if (from < f) 210 f = from; 211 if (to > t) 212 t = to; 213 priv = afs_page_dirty(f, t); 214 set_page_private(page, priv); 215 trace_afs_page_dirty(vnode, tracepoint_string("dirty+"), 216 page->index, priv); 217 } else { 218 priv = afs_page_dirty(from, to); 219 attach_page_private(page, (void *)priv); 220 trace_afs_page_dirty(vnode, tracepoint_string("dirty"), 221 page->index, priv); 222 } 223 224 set_page_dirty(page); 225 if (PageDirty(page)) 226 _debug("dirtied"); 227 ret = copied; 228 229out: 230 unlock_page(page); 231 put_page(page); 232 return ret; 233} 234 235/* 236 * kill all the pages in the given range 237 */ 238static void afs_kill_pages(struct address_space *mapping, 239 pgoff_t first, pgoff_t last) 240{ 241 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 242 struct pagevec pv; 243 unsigned count, loop; 244 245 _enter("{%llx:%llu},%lx-%lx", 246 vnode->fid.vid, vnode->fid.vnode, first, last); 247 248 pagevec_init(&pv); 249 250 do { 251 _debug("kill %lx-%lx", first, last); 252 253 count = last - first + 1; 254 if (count > PAGEVEC_SIZE) 255 count = PAGEVEC_SIZE; 256 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); 257 ASSERTCMP(pv.nr, ==, count); 258 259 for (loop = 0; loop < count; loop++) { 260 struct page *page = pv.pages[loop]; 261 ClearPageUptodate(page); 262 SetPageError(page); 263 end_page_writeback(page); 264 if (page->index >= first) 265 first = page->index + 1; 266 lock_page(page); 267 generic_error_remove_page(mapping, page); 268 unlock_page(page); 269 } 270 271 __pagevec_release(&pv); 272 } while (first <= last); 273 274 _leave(""); 275} 276 277/* 278 * Redirty all the pages in a given range. 279 */ 280static void afs_redirty_pages(struct writeback_control *wbc, 281 struct address_space *mapping, 282 pgoff_t first, pgoff_t last) 283{ 284 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 285 struct pagevec pv; 286 unsigned count, loop; 287 288 _enter("{%llx:%llu},%lx-%lx", 289 vnode->fid.vid, vnode->fid.vnode, first, last); 290 291 pagevec_init(&pv); 292 293 do { 294 _debug("redirty %lx-%lx", first, last); 295 296 count = last - first + 1; 297 if (count > PAGEVEC_SIZE) 298 count = PAGEVEC_SIZE; 299 pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); 300 ASSERTCMP(pv.nr, ==, count); 301 302 for (loop = 0; loop < count; loop++) { 303 struct page *page = pv.pages[loop]; 304 305 redirty_page_for_writepage(wbc, page); 306 end_page_writeback(page); 307 if (page->index >= first) 308 first = page->index + 1; 309 } 310 311 __pagevec_release(&pv); 312 } while (first <= last); 313 314 _leave(""); 315} 316 317/* 318 * completion of write to server 319 */ 320static void afs_pages_written_back(struct afs_vnode *vnode, 321 pgoff_t first, pgoff_t last) 322{ 323 struct pagevec pv; 324 unsigned long priv; 325 unsigned count, loop; 326 327 _enter("{%llx:%llu},{%lx-%lx}", 328 vnode->fid.vid, vnode->fid.vnode, first, last); 329 330 pagevec_init(&pv); 331 332 do { 333 _debug("done %lx-%lx", first, last); 334 335 count = last - first + 1; 336 if (count > PAGEVEC_SIZE) 337 count = PAGEVEC_SIZE; 338 pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, 339 first, count, pv.pages); 340 ASSERTCMP(pv.nr, ==, count); 341 342 for (loop = 0; loop < count; loop++) { 343 priv = (unsigned long)detach_page_private(pv.pages[loop]); 344 trace_afs_page_dirty(vnode, tracepoint_string("clear"), 345 pv.pages[loop]->index, priv); 346 end_page_writeback(pv.pages[loop]); 347 } 348 first += count; 349 __pagevec_release(&pv); 350 } while (first <= last); 351 352 afs_prune_wb_keys(vnode); 353 _leave(""); 354} 355 356/* 357 * Find a key to use for the writeback. We cached the keys used to author the 358 * writes on the vnode. *_wbk will contain the last writeback key used or NULL 359 * and we need to start from there if it's set. 360 */ 361static int afs_get_writeback_key(struct afs_vnode *vnode, 362 struct afs_wb_key **_wbk) 363{ 364 struct afs_wb_key *wbk = NULL; 365 struct list_head *p; 366 int ret = -ENOKEY, ret2; 367 368 spin_lock(&vnode->wb_lock); 369 if (*_wbk) 370 p = (*_wbk)->vnode_link.next; 371 else 372 p = vnode->wb_keys.next; 373 374 while (p != &vnode->wb_keys) { 375 wbk = list_entry(p, struct afs_wb_key, vnode_link); 376 _debug("wbk %u", key_serial(wbk->key)); 377 ret2 = key_validate(wbk->key); 378 if (ret2 == 0) { 379 refcount_inc(&wbk->usage); 380 _debug("USE WB KEY %u", key_serial(wbk->key)); 381 break; 382 } 383 384 wbk = NULL; 385 if (ret == -ENOKEY) 386 ret = ret2; 387 p = p->next; 388 } 389 390 spin_unlock(&vnode->wb_lock); 391 if (*_wbk) 392 afs_put_wb_key(*_wbk); 393 *_wbk = wbk; 394 return 0; 395} 396 397static void afs_store_data_success(struct afs_operation *op) 398{ 399 struct afs_vnode *vnode = op->file[0].vnode; 400 401 op->ctime = op->file[0].scb.status.mtime_client; 402 afs_vnode_commit_status(op, &op->file[0]); 403 if (op->error == 0) { 404 if (!op->store.laundering) 405 afs_pages_written_back(vnode, op->store.first, op->store.last); 406 afs_stat_v(vnode, n_stores); 407 atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) - 408 (op->store.first * PAGE_SIZE + op->store.first_offset), 409 &afs_v2net(vnode)->n_store_bytes); 410 } 411} 412 413static const struct afs_operation_ops afs_store_data_operation = { 414 .issue_afs_rpc = afs_fs_store_data, 415 .issue_yfs_rpc = yfs_fs_store_data, 416 .success = afs_store_data_success, 417}; 418 419/* 420 * write to a file 421 */ 422static int afs_store_data(struct address_space *mapping, 423 pgoff_t first, pgoff_t last, 424 unsigned offset, unsigned to, bool laundering) 425{ 426 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 427 struct afs_operation *op; 428 struct afs_wb_key *wbk = NULL; 429 int ret; 430 431 _enter("%s{%llx:%llu.%u},%lx,%lx,%x,%x", 432 vnode->volume->name, 433 vnode->fid.vid, 434 vnode->fid.vnode, 435 vnode->fid.unique, 436 first, last, offset, to); 437 438 ret = afs_get_writeback_key(vnode, &wbk); 439 if (ret) { 440 _leave(" = %d [no keys]", ret); 441 return ret; 442 } 443 444 op = afs_alloc_operation(wbk->key, vnode->volume); 445 if (IS_ERR(op)) { 446 afs_put_wb_key(wbk); 447 return -ENOMEM; 448 } 449 450 afs_op_set_vnode(op, 0, vnode); 451 op->file[0].dv_delta = 1; 452 op->store.mapping = mapping; 453 op->file[0].modification = true; 454 op->store.first = first; 455 op->store.last = last; 456 op->store.first_offset = offset; 457 op->store.last_to = to; 458 op->store.laundering = laundering; 459 op->mtime = vnode->vfs_inode.i_mtime; 460 op->flags |= AFS_OPERATION_UNINTR; 461 op->ops = &afs_store_data_operation; 462 463try_next_key: 464 afs_begin_vnode_operation(op); 465 afs_wait_for_operation(op); 466 467 switch (op->error) { 468 case -EACCES: 469 case -EPERM: 470 case -ENOKEY: 471 case -EKEYEXPIRED: 472 case -EKEYREJECTED: 473 case -EKEYREVOKED: 474 _debug("next"); 475 476 ret = afs_get_writeback_key(vnode, &wbk); 477 if (ret == 0) { 478 key_put(op->key); 479 op->key = key_get(wbk->key); 480 goto try_next_key; 481 } 482 break; 483 } 484 485 afs_put_wb_key(wbk); 486 _leave(" = %d", op->error); 487 return afs_put_operation(op); 488} 489 490/* 491 * Synchronously write back the locked page and any subsequent non-locked dirty 492 * pages. 493 */ 494static int afs_write_back_from_locked_page(struct address_space *mapping, 495 struct writeback_control *wbc, 496 struct page *primary_page, 497 pgoff_t final_page) 498{ 499 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 500 struct page *pages[8], *page; 501 unsigned long count, priv; 502 unsigned n, offset, to, f, t; 503 pgoff_t start, first, last; 504 loff_t i_size, end; 505 int loop, ret; 506 507 _enter(",%lx", primary_page->index); 508 509 count = 1; 510 if (test_set_page_writeback(primary_page)) 511 BUG(); 512 513 /* Find all consecutive lockable dirty pages that have contiguous 514 * written regions, stopping when we find a page that is not 515 * immediately lockable, is not dirty or is missing, or we reach the 516 * end of the range. 517 */ 518 start = primary_page->index; 519 priv = page_private(primary_page); 520 offset = afs_page_dirty_from(priv); 521 to = afs_page_dirty_to(priv); 522 trace_afs_page_dirty(vnode, tracepoint_string("store"), 523 primary_page->index, priv); 524 525 WARN_ON(offset == to); 526 if (offset == to) 527 trace_afs_page_dirty(vnode, tracepoint_string("WARN"), 528 primary_page->index, priv); 529 530 if (start >= final_page || 531 (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))) 532 goto no_more; 533 534 start++; 535 do { 536 _debug("more %lx [%lx]", start, count); 537 n = final_page - start + 1; 538 if (n > ARRAY_SIZE(pages)) 539 n = ARRAY_SIZE(pages); 540 n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages); 541 _debug("fgpc %u", n); 542 if (n == 0) 543 goto no_more; 544 if (pages[0]->index != start) { 545 do { 546 put_page(pages[--n]); 547 } while (n > 0); 548 goto no_more; 549 } 550 551 for (loop = 0; loop < n; loop++) { 552 page = pages[loop]; 553 if (to != PAGE_SIZE && 554 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) 555 break; 556 if (page->index > final_page) 557 break; 558 if (!trylock_page(page)) 559 break; 560 if (!PageDirty(page) || PageWriteback(page)) { 561 unlock_page(page); 562 break; 563 } 564 565 priv = page_private(page); 566 f = afs_page_dirty_from(priv); 567 t = afs_page_dirty_to(priv); 568 if (f != 0 && 569 !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) { 570 unlock_page(page); 571 break; 572 } 573 to = t; 574 575 trace_afs_page_dirty(vnode, tracepoint_string("store+"), 576 page->index, priv); 577 578 if (!clear_page_dirty_for_io(page)) 579 BUG(); 580 if (test_set_page_writeback(page)) 581 BUG(); 582 unlock_page(page); 583 put_page(page); 584 } 585 count += loop; 586 if (loop < n) { 587 for (; loop < n; loop++) 588 put_page(pages[loop]); 589 goto no_more; 590 } 591 592 start += loop; 593 } while (start <= final_page && count < 65536); 594 595no_more: 596 /* We now have a contiguous set of dirty pages, each with writeback 597 * set; the first page is still locked at this point, but all the rest 598 * have been unlocked. 599 */ 600 unlock_page(primary_page); 601 602 first = primary_page->index; 603 last = first + count - 1; 604 605 end = (loff_t)last * PAGE_SIZE + to; 606 i_size = i_size_read(&vnode->vfs_inode); 607 608 _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); 609 if (end > i_size) 610 to = i_size & ~PAGE_MASK; 611 612 ret = afs_store_data(mapping, first, last, offset, to, false); 613 switch (ret) { 614 case 0: 615 ret = count; 616 break; 617 618 default: 619 pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret); 620 fallthrough; 621 case -EACCES: 622 case -EPERM: 623 case -ENOKEY: 624 case -EKEYEXPIRED: 625 case -EKEYREJECTED: 626 case -EKEYREVOKED: 627 afs_redirty_pages(wbc, mapping, first, last); 628 mapping_set_error(mapping, ret); 629 break; 630 631 case -EDQUOT: 632 case -ENOSPC: 633 afs_redirty_pages(wbc, mapping, first, last); 634 mapping_set_error(mapping, -ENOSPC); 635 break; 636 637 case -EROFS: 638 case -EIO: 639 case -EREMOTEIO: 640 case -EFBIG: 641 case -ENOENT: 642 case -ENOMEDIUM: 643 case -ENXIO: 644 trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail); 645 afs_kill_pages(mapping, first, last); 646 mapping_set_error(mapping, ret); 647 break; 648 } 649 650 _leave(" = %d", ret); 651 return ret; 652} 653 654/* 655 * write a page back to the server 656 * - the caller locked the page for us 657 */ 658int afs_writepage(struct page *page, struct writeback_control *wbc) 659{ 660 int ret; 661 662 _enter("{%lx},", page->index); 663 664 ret = afs_write_back_from_locked_page(page->mapping, wbc, page, 665 wbc->range_end >> PAGE_SHIFT); 666 if (ret < 0) { 667 _leave(" = %d", ret); 668 return 0; 669 } 670 671 wbc->nr_to_write -= ret; 672 673 _leave(" = 0"); 674 return 0; 675} 676 677/* 678 * write a region of pages back to the server 679 */ 680static int afs_writepages_region(struct address_space *mapping, 681 struct writeback_control *wbc, 682 pgoff_t index, pgoff_t end, pgoff_t *_next) 683{ 684 struct page *page; 685 int ret, n; 686 687 _enter(",,%lx,%lx,", index, end); 688 689 do { 690 n = find_get_pages_range_tag(mapping, &index, end, 691 PAGECACHE_TAG_DIRTY, 1, &page); 692 if (!n) 693 break; 694 695 _debug("wback %lx", page->index); 696 697 /* 698 * at this point we hold neither the i_pages lock nor the 699 * page lock: the page may be truncated or invalidated 700 * (changing page->mapping to NULL), or even swizzled 701 * back from swapper_space to tmpfs file mapping 702 */ 703 ret = lock_page_killable(page); 704 if (ret < 0) { 705 put_page(page); 706 _leave(" = %d", ret); 707 return ret; 708 } 709 710 if (page->mapping != mapping || !PageDirty(page)) { 711 unlock_page(page); 712 put_page(page); 713 continue; 714 } 715 716 if (PageWriteback(page)) { 717 unlock_page(page); 718 if (wbc->sync_mode != WB_SYNC_NONE) 719 wait_on_page_writeback(page); 720 put_page(page); 721 continue; 722 } 723 724 if (!clear_page_dirty_for_io(page)) 725 BUG(); 726 ret = afs_write_back_from_locked_page(mapping, wbc, page, end); 727 put_page(page); 728 if (ret < 0) { 729 _leave(" = %d", ret); 730 return ret; 731 } 732 733 wbc->nr_to_write -= ret; 734 735 cond_resched(); 736 } while (index < end && wbc->nr_to_write > 0); 737 738 *_next = index; 739 _leave(" = 0 [%lx]", *_next); 740 return 0; 741} 742 743/* 744 * write some of the pending data back to the server 745 */ 746int afs_writepages(struct address_space *mapping, 747 struct writeback_control *wbc) 748{ 749 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 750 pgoff_t start, end, next; 751 int ret; 752 753 _enter(""); 754 755 /* We have to be careful as we can end up racing with setattr() 756 * truncating the pagecache since the caller doesn't take a lock here 757 * to prevent it. 758 */ 759 if (wbc->sync_mode == WB_SYNC_ALL) 760 down_read(&vnode->validate_lock); 761 else if (!down_read_trylock(&vnode->validate_lock)) 762 return 0; 763 764 if (wbc->range_cyclic) { 765 start = mapping->writeback_index; 766 end = -1; 767 ret = afs_writepages_region(mapping, wbc, start, end, &next); 768 if (start > 0 && wbc->nr_to_write > 0 && ret == 0) 769 ret = afs_writepages_region(mapping, wbc, 0, start, 770 &next); 771 mapping->writeback_index = next; 772 } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { 773 end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); 774 ret = afs_writepages_region(mapping, wbc, 0, end, &next); 775 if (wbc->nr_to_write > 0) 776 mapping->writeback_index = next; 777 } else { 778 start = wbc->range_start >> PAGE_SHIFT; 779 end = wbc->range_end >> PAGE_SHIFT; 780 ret = afs_writepages_region(mapping, wbc, start, end, &next); 781 } 782 783 up_read(&vnode->validate_lock); 784 _leave(" = %d", ret); 785 return ret; 786} 787 788/* 789 * write to an AFS file 790 */ 791ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) 792{ 793 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); 794 ssize_t result; 795 size_t count = iov_iter_count(from); 796 797 _enter("{%llx:%llu},{%zu},", 798 vnode->fid.vid, vnode->fid.vnode, count); 799 800 if (IS_SWAPFILE(&vnode->vfs_inode)) { 801 printk(KERN_INFO 802 "AFS: Attempt to write to active swap file!\n"); 803 return -EBUSY; 804 } 805 806 if (!count) 807 return 0; 808 809 result = generic_file_write_iter(iocb, from); 810 811 _leave(" = %zd", result); 812 return result; 813} 814 815/* 816 * flush any dirty pages for this process, and check for write errors. 817 * - the return status from this call provides a reliable indication of 818 * whether any write errors occurred for this process. 819 */ 820int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) 821{ 822 struct inode *inode = file_inode(file); 823 struct afs_vnode *vnode = AFS_FS_I(inode); 824 825 _enter("{%llx:%llu},{n=%pD},%d", 826 vnode->fid.vid, vnode->fid.vnode, file, 827 datasync); 828 829 return file_write_and_wait_range(file, start, end); 830} 831 832/* 833 * notification that a previously read-only page is about to become writable 834 * - if it returns an error, the caller will deliver a bus error signal 835 */ 836vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) 837{ 838 struct file *file = vmf->vma->vm_file; 839 struct inode *inode = file_inode(file); 840 struct afs_vnode *vnode = AFS_FS_I(inode); 841 unsigned long priv; 842 843 _enter("{{%llx:%llu}},{%lx}", 844 vnode->fid.vid, vnode->fid.vnode, vmf->page->index); 845 846 sb_start_pagefault(inode->i_sb); 847 848 /* Wait for the page to be written to the cache before we allow it to 849 * be modified. We then assume the entire page will need writing back. 850 */ 851#ifdef CONFIG_AFS_FSCACHE 852 fscache_wait_on_page_write(vnode->cache, vmf->page); 853#endif 854 855 if (PageWriteback(vmf->page) && 856 wait_on_page_bit_killable(vmf->page, PG_writeback) < 0) 857 return VM_FAULT_RETRY; 858 859 if (lock_page_killable(vmf->page) < 0) 860 return VM_FAULT_RETRY; 861 862 /* We mustn't change page->private until writeback is complete as that 863 * details the portion of the page we need to write back and we might 864 * need to redirty the page if there's a problem. 865 */ 866 wait_on_page_writeback(vmf->page); 867 868 priv = afs_page_dirty(0, PAGE_SIZE); 869 priv = afs_page_dirty_mmapped(priv); 870 trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), 871 vmf->page->index, priv); 872 if (PagePrivate(vmf->page)) 873 set_page_private(vmf->page, priv); 874 else 875 attach_page_private(vmf->page, (void *)priv); 876 file_update_time(file); 877 878 sb_end_pagefault(inode->i_sb); 879 return VM_FAULT_LOCKED; 880} 881 882/* 883 * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. 884 */ 885void afs_prune_wb_keys(struct afs_vnode *vnode) 886{ 887 LIST_HEAD(graveyard); 888 struct afs_wb_key *wbk, *tmp; 889 890 /* Discard unused keys */ 891 spin_lock(&vnode->wb_lock); 892 893 if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) && 894 !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) { 895 list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { 896 if (refcount_read(&wbk->usage) == 1) 897 list_move(&wbk->vnode_link, &graveyard); 898 } 899 } 900 901 spin_unlock(&vnode->wb_lock); 902 903 while (!list_empty(&graveyard)) { 904 wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); 905 list_del(&wbk->vnode_link); 906 afs_put_wb_key(wbk); 907 } 908} 909 910/* 911 * Clean up a page during invalidation. 912 */ 913int afs_launder_page(struct page *page) 914{ 915 struct address_space *mapping = page->mapping; 916 struct afs_vnode *vnode = AFS_FS_I(mapping->host); 917 unsigned long priv; 918 unsigned int f, t; 919 int ret = 0; 920 921 _enter("{%lx}", page->index); 922 923 priv = page_private(page); 924 if (clear_page_dirty_for_io(page)) { 925 f = 0; 926 t = PAGE_SIZE; 927 if (PagePrivate(page)) { 928 f = afs_page_dirty_from(priv); 929 t = afs_page_dirty_to(priv); 930 } 931 932 trace_afs_page_dirty(vnode, tracepoint_string("launder"), 933 page->index, priv); 934 ret = afs_store_data(mapping, page->index, page->index, t, f, true); 935 } 936 937 priv = (unsigned long)detach_page_private(page); 938 trace_afs_page_dirty(vnode, tracepoint_string("laundered"), 939 page->index, priv); 940 941#ifdef CONFIG_AFS_FSCACHE 942 if (PageFsCache(page)) { 943 fscache_wait_on_page_write(vnode->cache, page); 944 fscache_uncache_page(vnode->cache, page); 945 } 946#endif 947 return ret; 948} 949