1 /* 2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. 3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. 4 * 5 * This copyrighted material is made available to anyone wishing to use, 6 * modify, copy, or redistribute it subject to the terms and conditions 7 * of the GNU General Public License version 2. 8 */ 9 10 #include <linux/sched.h> 11 #include <linux/slab.h> 12 #include <linux/spinlock.h> 13 #include <linux/completion.h> 14 #include <linux/buffer_head.h> 15 #include <linux/pagemap.h> 16 #include <linux/pagevec.h> 17 #include <linux/mpage.h> 18 #include <linux/fs.h> 19 #include <linux/writeback.h> 20 #include <linux/swap.h> 21 #include <linux/gfs2_ondisk.h> 22 #include <linux/backing-dev.h> 23 #include <linux/uio.h> 24 #include <trace/events/writeback.h> 25 #include <linux/sched/signal.h> 26 27 #include "gfs2.h" 28 #include "incore.h" 29 #include "bmap.h" 30 #include "glock.h" 31 #include "inode.h" 32 #include "log.h" 33 #include "meta_io.h" 34 #include "quota.h" 35 #include "trans.h" 36 #include "rgrp.h" 37 #include "super.h" 38 #include "util.h" 39 #include "glops.h" 40 #include "aops.h" 41 42 43 void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page, 44 unsigned int from, unsigned int len) 45 { 46 struct buffer_head *head = page_buffers(page); 47 unsigned int bsize = head->b_size; 48 struct buffer_head *bh; 49 unsigned int to = from + len; 50 unsigned int start, end; 51 52 for (bh = head, start = 0; bh != head || !start; 53 bh = bh->b_this_page, start = end) { 54 end = start + bsize; 55 if (end <= from) 56 continue; 57 if (start >= to) 58 break; 59 set_buffer_uptodate(bh); 60 gfs2_trans_add_data(ip->i_gl, bh); 61 } 62 } 63 64 /** 65 * gfs2_get_block_noalloc - Fills in a buffer head with details about a block 66 * @inode: The inode 67 * @lblock: The block number to look up 68 * @bh_result: The buffer head to return the result in 69 * @create: Non-zero if we may add block to the file 70 * 71 * Returns: errno 72 */ 73 74 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock, 75 struct buffer_head *bh_result, int create) 76 { 77 int error; 78 79 error = gfs2_block_map(inode, lblock, bh_result, 0); 80 if (error) 81 return error; 82 if (!buffer_mapped(bh_result)) 83 return -EIO; 84 return 0; 85 } 86 87 /** 88 * gfs2_writepage_common - Common bits of writepage 89 * @page: The page to be written 90 * @wbc: The writeback control 91 * 92 * Returns: 1 if writepage is ok, otherwise an error code or zero if no error. 93 */ 94 95 static int gfs2_writepage_common(struct page *page, 96 struct writeback_control *wbc) 97 { 98 struct inode *inode = page->mapping->host; 99 struct gfs2_inode *ip = GFS2_I(inode); 100 struct gfs2_sbd *sdp = GFS2_SB(inode); 101 loff_t i_size = i_size_read(inode); 102 pgoff_t end_index = i_size >> PAGE_SHIFT; 103 unsigned offset; 104 105 if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) 106 goto out; 107 if (current->journal_info) 108 goto redirty; 109 /* Is the page fully outside i_size? (truncate in progress) */ 110 offset = i_size & (PAGE_SIZE-1); 111 if (page->index > end_index || (page->index == end_index && !offset)) { 112 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE); 113 goto out; 114 } 115 return 1; 116 redirty: 117 redirty_page_for_writepage(wbc, page); 118 out: 119 unlock_page(page); 120 return 0; 121 } 122 123 /** 124 * gfs2_writepage - Write page for writeback mappings 125 * @page: The page 126 * @wbc: The writeback control 127 * 128 */ 129 130 static int gfs2_writepage(struct page *page, struct writeback_control *wbc) 131 { 132 int ret; 133 134 ret = gfs2_writepage_common(page, wbc); 135 if (ret <= 0) 136 return ret; 137 138 return nobh_writepage(page, gfs2_get_block_noalloc, wbc); 139 } 140 141 /* This is the same as calling block_write_full_page, but it also 142 * writes pages outside of i_size 143 */ 144 static int gfs2_write_full_page(struct page *page, get_block_t *get_block, 145 struct writeback_control *wbc) 146 { 147 struct inode * const inode = page->mapping->host; 148 loff_t i_size = i_size_read(inode); 149 const pgoff_t end_index = i_size >> PAGE_SHIFT; 150 unsigned offset; 151 152 /* 153 * The page straddles i_size. It must be zeroed out on each and every 154 * writepage invocation because it may be mmapped. "A file is mapped 155 * in multiples of the page size. For a file that is not a multiple of 156 * the page size, the remaining memory is zeroed when mapped, and 157 * writes to that region are not written out to the file." 158 */ 159 offset = i_size & (PAGE_SIZE-1); 160 if (page->index == end_index && offset) 161 zero_user_segment(page, offset, PAGE_SIZE); 162 163 return __block_write_full_page(inode, page, get_block, wbc, 164 end_buffer_async_write); 165 } 166 167 /** 168 * __gfs2_jdata_writepage - The core of jdata writepage 169 * @page: The page to write 170 * @wbc: The writeback control 171 * 172 * This is shared between writepage and writepages and implements the 173 * core of the writepage operation. If a transaction is required then 174 * PageChecked will have been set and the transaction will have 175 * already been started before this is called. 176 */ 177 178 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc) 179 { 180 struct inode *inode = page->mapping->host; 181 struct gfs2_inode *ip = GFS2_I(inode); 182 struct gfs2_sbd *sdp = GFS2_SB(inode); 183 184 if (PageChecked(page)) { 185 ClearPageChecked(page); 186 if (!page_has_buffers(page)) { 187 create_empty_buffers(page, inode->i_sb->s_blocksize, 188 BIT(BH_Dirty)|BIT(BH_Uptodate)); 189 } 190 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize); 191 } 192 return gfs2_write_full_page(page, gfs2_get_block_noalloc, wbc); 193 } 194 195 /** 196 * gfs2_jdata_writepage - Write complete page 197 * @page: Page to write 198 * @wbc: The writeback control 199 * 200 * Returns: errno 201 * 202 */ 203 204 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc) 205 { 206 struct inode *inode = page->mapping->host; 207 struct gfs2_inode *ip = GFS2_I(inode); 208 struct gfs2_sbd *sdp = GFS2_SB(inode); 209 int ret; 210 211 if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) 212 goto out; 213 if (PageChecked(page) || current->journal_info) 214 goto out_ignore; 215 ret = __gfs2_jdata_writepage(page, wbc); 216 return ret; 217 218 out_ignore: 219 redirty_page_for_writepage(wbc, page); 220 out: 221 unlock_page(page); 222 return 0; 223 } 224 225 /** 226 * gfs2_writepages - Write a bunch of dirty pages back to disk 227 * @mapping: The mapping to write 228 * @wbc: Write-back control 229 * 230 * Used for both ordered and writeback modes. 231 */ 232 static int gfs2_writepages(struct address_space *mapping, 233 struct writeback_control *wbc) 234 { 235 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); 236 int ret = mpage_writepages(mapping, wbc, gfs2_get_block_noalloc); 237 238 /* 239 * Even if we didn't write any pages here, we might still be holding 240 * dirty pages in the ail. We forcibly flush the ail because we don't 241 * want balance_dirty_pages() to loop indefinitely trying to write out 242 * pages held in the ail that it can't find. 243 */ 244 if (ret == 0) 245 set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags); 246 247 return ret; 248 } 249 250 /** 251 * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages 252 * @mapping: The mapping 253 * @wbc: The writeback control 254 * @pvec: The vector of pages 255 * @nr_pages: The number of pages to write 256 * @done_index: Page index 257 * 258 * Returns: non-zero if loop should terminate, zero otherwise 259 */ 260 261 static int gfs2_write_jdata_pagevec(struct address_space *mapping, 262 struct writeback_control *wbc, 263 struct pagevec *pvec, 264 int nr_pages, 265 pgoff_t *done_index) 266 { 267 struct inode *inode = mapping->host; 268 struct gfs2_sbd *sdp = GFS2_SB(inode); 269 unsigned nrblocks = nr_pages * (PAGE_SIZE/inode->i_sb->s_blocksize); 270 int i; 271 int ret; 272 273 ret = gfs2_trans_begin(sdp, nrblocks, nrblocks); 274 if (ret < 0) 275 return ret; 276 277 for(i = 0; i < nr_pages; i++) { 278 struct page *page = pvec->pages[i]; 279 280 *done_index = page->index; 281 282 lock_page(page); 283 284 if (unlikely(page->mapping != mapping)) { 285 continue_unlock: 286 unlock_page(page); 287 continue; 288 } 289 290 if (!PageDirty(page)) { 291 /* someone wrote it for us */ 292 goto continue_unlock; 293 } 294 295 if (PageWriteback(page)) { 296 if (wbc->sync_mode != WB_SYNC_NONE) 297 wait_on_page_writeback(page); 298 else 299 goto continue_unlock; 300 } 301 302 BUG_ON(PageWriteback(page)); 303 if (!clear_page_dirty_for_io(page)) 304 goto continue_unlock; 305 306 trace_wbc_writepage(wbc, inode_to_bdi(inode)); 307 308 ret = __gfs2_jdata_writepage(page, wbc); 309 if (unlikely(ret)) { 310 if (ret == AOP_WRITEPAGE_ACTIVATE) { 311 unlock_page(page); 312 ret = 0; 313 } else { 314 315 /* 316 * done_index is set past this page, 317 * so media errors will not choke 318 * background writeout for the entire 319 * file. This has consequences for 320 * range_cyclic semantics (ie. it may 321 * not be suitable for data integrity 322 * writeout). 323 */ 324 *done_index = page->index + 1; 325 ret = 1; 326 break; 327 } 328 } 329 330 /* 331 * We stop writing back only if we are not doing 332 * integrity sync. In case of integrity sync we have to 333 * keep going until we have written all the pages 334 * we tagged for writeback prior to entering this loop. 335 */ 336 if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) { 337 ret = 1; 338 break; 339 } 340 341 } 342 gfs2_trans_end(sdp); 343 return ret; 344 } 345 346 /** 347 * gfs2_write_cache_jdata - Like write_cache_pages but different 348 * @mapping: The mapping to write 349 * @wbc: The writeback control 350 * 351 * The reason that we use our own function here is that we need to 352 * start transactions before we grab page locks. This allows us 353 * to get the ordering right. 354 */ 355 356 static int gfs2_write_cache_jdata(struct address_space *mapping, 357 struct writeback_control *wbc) 358 { 359 int ret = 0; 360 int done = 0; 361 struct pagevec pvec; 362 int nr_pages; 363 pgoff_t uninitialized_var(writeback_index); 364 pgoff_t index; 365 pgoff_t end; 366 pgoff_t done_index; 367 int cycled; 368 int range_whole = 0; 369 int tag; 370 371 pagevec_init(&pvec); 372 if (wbc->range_cyclic) { 373 writeback_index = mapping->writeback_index; /* prev offset */ 374 index = writeback_index; 375 if (index == 0) 376 cycled = 1; 377 else 378 cycled = 0; 379 end = -1; 380 } else { 381 index = wbc->range_start >> PAGE_SHIFT; 382 end = wbc->range_end >> PAGE_SHIFT; 383 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 384 range_whole = 1; 385 cycled = 1; /* ignore range_cyclic tests */ 386 } 387 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) 388 tag = PAGECACHE_TAG_TOWRITE; 389 else 390 tag = PAGECACHE_TAG_DIRTY; 391 392 retry: 393 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) 394 tag_pages_for_writeback(mapping, index, end); 395 done_index = index; 396 while (!done && (index <= end)) { 397 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end, 398 tag); 399 if (nr_pages == 0) 400 break; 401 402 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, &done_index); 403 if (ret) 404 done = 1; 405 if (ret > 0) 406 ret = 0; 407 pagevec_release(&pvec); 408 cond_resched(); 409 } 410 411 if (!cycled && !done) { 412 /* 413 * range_cyclic: 414 * We hit the last page and there is more work to be done: wrap 415 * back to the start of the file 416 */ 417 cycled = 1; 418 index = 0; 419 end = writeback_index - 1; 420 goto retry; 421 } 422 423 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 424 mapping->writeback_index = done_index; 425 426 return ret; 427 } 428 429 430 /** 431 * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk 432 * @mapping: The mapping to write 433 * @wbc: The writeback control 434 * 435 */ 436 437 static int gfs2_jdata_writepages(struct address_space *mapping, 438 struct writeback_control *wbc) 439 { 440 struct gfs2_inode *ip = GFS2_I(mapping->host); 441 struct gfs2_sbd *sdp = GFS2_SB(mapping->host); 442 int ret; 443 444 ret = gfs2_write_cache_jdata(mapping, wbc); 445 if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) { 446 gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL | 447 GFS2_LFC_JDATA_WPAGES); 448 ret = gfs2_write_cache_jdata(mapping, wbc); 449 } 450 return ret; 451 } 452 453 /** 454 * stuffed_readpage - Fill in a Linux page with stuffed file data 455 * @ip: the inode 456 * @page: the page 457 * 458 * Returns: errno 459 */ 460 461 int stuffed_readpage(struct gfs2_inode *ip, struct page *page) 462 { 463 struct buffer_head *dibh; 464 u64 dsize = i_size_read(&ip->i_inode); 465 void *kaddr; 466 int error; 467 468 /* 469 * Due to the order of unstuffing files and ->fault(), we can be 470 * asked for a zero page in the case of a stuffed file being extended, 471 * so we need to supply one here. It doesn't happen often. 472 */ 473 if (unlikely(page->index)) { 474 zero_user(page, 0, PAGE_SIZE); 475 SetPageUptodate(page); 476 return 0; 477 } 478 479 error = gfs2_meta_inode_buffer(ip, &dibh); 480 if (error) 481 return error; 482 483 kaddr = kmap_atomic(page); 484 if (dsize > gfs2_max_stuffed_size(ip)) 485 dsize = gfs2_max_stuffed_size(ip); 486 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize); 487 memset(kaddr + dsize, 0, PAGE_SIZE - dsize); 488 kunmap_atomic(kaddr); 489 flush_dcache_page(page); 490 brelse(dibh); 491 SetPageUptodate(page); 492 493 return 0; 494 } 495 496 497 /** 498 * __gfs2_readpage - readpage 499 * @file: The file to read a page for 500 * @page: The page to read 501 * 502 * This is the core of gfs2's readpage. It's used by the internal file 503 * reading code as in that case we already hold the glock. Also it's 504 * called by gfs2_readpage() once the required lock has been granted. 505 */ 506 507 static int __gfs2_readpage(void *file, struct page *page) 508 { 509 struct gfs2_inode *ip = GFS2_I(page->mapping->host); 510 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host); 511 int error; 512 513 if (gfs2_is_stuffed(ip)) { 514 error = stuffed_readpage(ip, page); 515 unlock_page(page); 516 } else { 517 error = mpage_readpage(page, gfs2_block_map); 518 } 519 520 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 521 return -EIO; 522 523 return error; 524 } 525 526 /** 527 * gfs2_readpage - read a page of a file 528 * @file: The file to read 529 * @page: The page of the file 530 * 531 * This deals with the locking required. We have to unlock and 532 * relock the page in order to get the locking in the right 533 * order. 534 */ 535 536 static int gfs2_readpage(struct file *file, struct page *page) 537 { 538 struct address_space *mapping = page->mapping; 539 struct gfs2_inode *ip = GFS2_I(mapping->host); 540 struct gfs2_holder gh; 541 int error; 542 543 unlock_page(page); 544 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); 545 error = gfs2_glock_nq(&gh); 546 if (unlikely(error)) 547 goto out; 548 error = AOP_TRUNCATED_PAGE; 549 lock_page(page); 550 if (page->mapping == mapping && !PageUptodate(page)) 551 error = __gfs2_readpage(file, page); 552 else 553 unlock_page(page); 554 gfs2_glock_dq(&gh); 555 out: 556 gfs2_holder_uninit(&gh); 557 if (error && error != AOP_TRUNCATED_PAGE) 558 lock_page(page); 559 return error; 560 } 561 562 /** 563 * gfs2_internal_read - read an internal file 564 * @ip: The gfs2 inode 565 * @buf: The buffer to fill 566 * @pos: The file position 567 * @size: The amount to read 568 * 569 */ 570 571 int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos, 572 unsigned size) 573 { 574 struct address_space *mapping = ip->i_inode.i_mapping; 575 unsigned long index = *pos / PAGE_SIZE; 576 unsigned offset = *pos & (PAGE_SIZE - 1); 577 unsigned copied = 0; 578 unsigned amt; 579 struct page *page; 580 void *p; 581 582 do { 583 amt = size - copied; 584 if (offset + size > PAGE_SIZE) 585 amt = PAGE_SIZE - offset; 586 page = read_cache_page(mapping, index, __gfs2_readpage, NULL); 587 if (IS_ERR(page)) 588 return PTR_ERR(page); 589 p = kmap_atomic(page); 590 memcpy(buf + copied, p + offset, amt); 591 kunmap_atomic(p); 592 put_page(page); 593 copied += amt; 594 index++; 595 offset = 0; 596 } while(copied < size); 597 (*pos) += size; 598 return size; 599 } 600 601 /** 602 * gfs2_readpages - Read a bunch of pages at once 603 * @file: The file to read from 604 * @mapping: Address space info 605 * @pages: List of pages to read 606 * @nr_pages: Number of pages to read 607 * 608 * Some notes: 609 * 1. This is only for readahead, so we can simply ignore any things 610 * which are slightly inconvenient (such as locking conflicts between 611 * the page lock and the glock) and return having done no I/O. Its 612 * obviously not something we'd want to do on too regular a basis. 613 * Any I/O we ignore at this time will be done via readpage later. 614 * 2. We don't handle stuffed files here we let readpage do the honours. 615 * 3. mpage_readpages() does most of the heavy lifting in the common case. 616 * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places. 617 */ 618 619 static int gfs2_readpages(struct file *file, struct address_space *mapping, 620 struct list_head *pages, unsigned nr_pages) 621 { 622 struct inode *inode = mapping->host; 623 struct gfs2_inode *ip = GFS2_I(inode); 624 struct gfs2_sbd *sdp = GFS2_SB(inode); 625 struct gfs2_holder gh; 626 int ret; 627 628 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); 629 ret = gfs2_glock_nq(&gh); 630 if (unlikely(ret)) 631 goto out_uninit; 632 if (!gfs2_is_stuffed(ip)) 633 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map); 634 gfs2_glock_dq(&gh); 635 out_uninit: 636 gfs2_holder_uninit(&gh); 637 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 638 ret = -EIO; 639 return ret; 640 } 641 642 /** 643 * adjust_fs_space - Adjusts the free space available due to gfs2_grow 644 * @inode: the rindex inode 645 */ 646 void adjust_fs_space(struct inode *inode) 647 { 648 struct gfs2_sbd *sdp = inode->i_sb->s_fs_info; 649 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); 650 struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode); 651 struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master; 652 struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local; 653 struct buffer_head *m_bh, *l_bh; 654 u64 fs_total, new_free; 655 656 /* Total up the file system space, according to the latest rindex. */ 657 fs_total = gfs2_ri_total(sdp); 658 if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0) 659 return; 660 661 spin_lock(&sdp->sd_statfs_spin); 662 gfs2_statfs_change_in(m_sc, m_bh->b_data + 663 sizeof(struct gfs2_dinode)); 664 if (fs_total > (m_sc->sc_total + l_sc->sc_total)) 665 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total); 666 else 667 new_free = 0; 668 spin_unlock(&sdp->sd_statfs_spin); 669 fs_warn(sdp, "File system extended by %llu blocks.\n", 670 (unsigned long long)new_free); 671 gfs2_statfs_change(sdp, new_free, new_free, 0); 672 673 if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0) 674 goto out; 675 update_statfs(sdp, m_bh, l_bh); 676 brelse(l_bh); 677 out: 678 brelse(m_bh); 679 } 680 681 /** 682 * gfs2_stuffed_write_end - Write end for stuffed files 683 * @inode: The inode 684 * @dibh: The buffer_head containing the on-disk inode 685 * @pos: The file position 686 * @copied: How much was actually copied by the VFS 687 * @page: The page 688 * 689 * This copies the data from the page into the inode block after 690 * the inode data structure itself. 691 * 692 * Returns: copied bytes or errno 693 */ 694 int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh, 695 loff_t pos, unsigned copied, 696 struct page *page) 697 { 698 struct gfs2_inode *ip = GFS2_I(inode); 699 u64 to = pos + copied; 700 void *kaddr; 701 unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode); 702 703 BUG_ON(pos + copied > gfs2_max_stuffed_size(ip)); 704 705 kaddr = kmap_atomic(page); 706 memcpy(buf + pos, kaddr + pos, copied); 707 flush_dcache_page(page); 708 kunmap_atomic(kaddr); 709 710 WARN_ON(!PageUptodate(page)); 711 unlock_page(page); 712 put_page(page); 713 714 if (copied) { 715 if (inode->i_size < to) 716 i_size_write(inode, to); 717 mark_inode_dirty(inode); 718 } 719 return copied; 720 } 721 722 /** 723 * jdata_set_page_dirty - Page dirtying function 724 * @page: The page to dirty 725 * 726 * Returns: 1 if it dirtyed the page, or 0 otherwise 727 */ 728 729 static int jdata_set_page_dirty(struct page *page) 730 { 731 SetPageChecked(page); 732 return __set_page_dirty_buffers(page); 733 } 734 735 /** 736 * gfs2_bmap - Block map function 737 * @mapping: Address space info 738 * @lblock: The block to map 739 * 740 * Returns: The disk address for the block or 0 on hole or error 741 */ 742 743 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock) 744 { 745 struct gfs2_inode *ip = GFS2_I(mapping->host); 746 struct gfs2_holder i_gh; 747 sector_t dblock = 0; 748 int error; 749 750 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); 751 if (error) 752 return 0; 753 754 if (!gfs2_is_stuffed(ip)) 755 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map); 756 757 gfs2_glock_dq_uninit(&i_gh); 758 759 return dblock; 760 } 761 762 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh) 763 { 764 struct gfs2_bufdata *bd; 765 766 lock_buffer(bh); 767 gfs2_log_lock(sdp); 768 clear_buffer_dirty(bh); 769 bd = bh->b_private; 770 if (bd) { 771 if (!list_empty(&bd->bd_list) && !buffer_pinned(bh)) 772 list_del_init(&bd->bd_list); 773 else 774 gfs2_remove_from_journal(bh, REMOVE_JDATA); 775 } 776 bh->b_bdev = NULL; 777 clear_buffer_mapped(bh); 778 clear_buffer_req(bh); 779 clear_buffer_new(bh); 780 gfs2_log_unlock(sdp); 781 unlock_buffer(bh); 782 } 783 784 static void gfs2_invalidatepage(struct page *page, unsigned int offset, 785 unsigned int length) 786 { 787 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host); 788 unsigned int stop = offset + length; 789 int partial_page = (offset || length < PAGE_SIZE); 790 struct buffer_head *bh, *head; 791 unsigned long pos = 0; 792 793 BUG_ON(!PageLocked(page)); 794 if (!partial_page) 795 ClearPageChecked(page); 796 if (!page_has_buffers(page)) 797 goto out; 798 799 bh = head = page_buffers(page); 800 do { 801 if (pos + bh->b_size > stop) 802 return; 803 804 if (offset <= pos) 805 gfs2_discard(sdp, bh); 806 pos += bh->b_size; 807 bh = bh->b_this_page; 808 } while (bh != head); 809 out: 810 if (!partial_page) 811 try_to_release_page(page, 0); 812 } 813 814 /** 815 * gfs2_releasepage - free the metadata associated with a page 816 * @page: the page that's being released 817 * @gfp_mask: passed from Linux VFS, ignored by us 818 * 819 * Call try_to_free_buffers() if the buffers in this page can be 820 * released. 821 * 822 * Returns: 0 823 */ 824 825 int gfs2_releasepage(struct page *page, gfp_t gfp_mask) 826 { 827 struct address_space *mapping = page->mapping; 828 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); 829 struct buffer_head *bh, *head; 830 struct gfs2_bufdata *bd; 831 832 if (!page_has_buffers(page)) 833 return 0; 834 835 /* 836 * From xfs_vm_releasepage: mm accommodates an old ext3 case where 837 * clean pages might not have had the dirty bit cleared. Thus, it can 838 * send actual dirty pages to ->releasepage() via shrink_active_list(). 839 * 840 * As a workaround, we skip pages that contain dirty buffers below. 841 * Once ->releasepage isn't called on dirty pages anymore, we can warn 842 * on dirty buffers like we used to here again. 843 */ 844 845 gfs2_log_lock(sdp); 846 spin_lock(&sdp->sd_ail_lock); 847 head = bh = page_buffers(page); 848 do { 849 if (atomic_read(&bh->b_count)) 850 goto cannot_release; 851 bd = bh->b_private; 852 if (bd && bd->bd_tr) 853 goto cannot_release; 854 if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh))) 855 goto cannot_release; 856 bh = bh->b_this_page; 857 } while(bh != head); 858 spin_unlock(&sdp->sd_ail_lock); 859 860 head = bh = page_buffers(page); 861 do { 862 bd = bh->b_private; 863 if (bd) { 864 gfs2_assert_warn(sdp, bd->bd_bh == bh); 865 if (!list_empty(&bd->bd_list)) 866 list_del_init(&bd->bd_list); 867 bd->bd_bh = NULL; 868 bh->b_private = NULL; 869 kmem_cache_free(gfs2_bufdata_cachep, bd); 870 } 871 872 bh = bh->b_this_page; 873 } while (bh != head); 874 gfs2_log_unlock(sdp); 875 876 return try_to_free_buffers(page); 877 878 cannot_release: 879 spin_unlock(&sdp->sd_ail_lock); 880 gfs2_log_unlock(sdp); 881 return 0; 882 } 883 884 static const struct address_space_operations gfs2_writeback_aops = { 885 .writepage = gfs2_writepage, 886 .writepages = gfs2_writepages, 887 .readpage = gfs2_readpage, 888 .readpages = gfs2_readpages, 889 .bmap = gfs2_bmap, 890 .invalidatepage = gfs2_invalidatepage, 891 .releasepage = gfs2_releasepage, 892 .direct_IO = noop_direct_IO, 893 .migratepage = buffer_migrate_page, 894 .is_partially_uptodate = block_is_partially_uptodate, 895 .error_remove_page = generic_error_remove_page, 896 }; 897 898 static const struct address_space_operations gfs2_ordered_aops = { 899 .writepage = gfs2_writepage, 900 .writepages = gfs2_writepages, 901 .readpage = gfs2_readpage, 902 .readpages = gfs2_readpages, 903 .set_page_dirty = __set_page_dirty_buffers, 904 .bmap = gfs2_bmap, 905 .invalidatepage = gfs2_invalidatepage, 906 .releasepage = gfs2_releasepage, 907 .direct_IO = noop_direct_IO, 908 .migratepage = buffer_migrate_page, 909 .is_partially_uptodate = block_is_partially_uptodate, 910 .error_remove_page = generic_error_remove_page, 911 }; 912 913 static const struct address_space_operations gfs2_jdata_aops = { 914 .writepage = gfs2_jdata_writepage, 915 .writepages = gfs2_jdata_writepages, 916 .readpage = gfs2_readpage, 917 .readpages = gfs2_readpages, 918 .set_page_dirty = jdata_set_page_dirty, 919 .bmap = gfs2_bmap, 920 .invalidatepage = gfs2_invalidatepage, 921 .releasepage = gfs2_releasepage, 922 .is_partially_uptodate = block_is_partially_uptodate, 923 .error_remove_page = generic_error_remove_page, 924 }; 925 926 void gfs2_set_aops(struct inode *inode) 927 { 928 struct gfs2_inode *ip = GFS2_I(inode); 929 930 if (gfs2_is_writeback(ip)) 931 inode->i_mapping->a_ops = &gfs2_writeback_aops; 932 else if (gfs2_is_ordered(ip)) 933 inode->i_mapping->a_ops = &gfs2_ordered_aops; 934 else if (gfs2_is_jdata(ip)) 935 inode->i_mapping->a_ops = &gfs2_jdata_aops; 936 else 937 BUG(); 938 } 939 940