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