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 24 #include "gfs2.h" 25 #include "incore.h" 26 #include "bmap.h" 27 #include "glock.h" 28 #include "inode.h" 29 #include "log.h" 30 #include "meta_io.h" 31 #include "quota.h" 32 #include "trans.h" 33 #include "rgrp.h" 34 #include "super.h" 35 #include "util.h" 36 #include "glops.h" 37 38 39 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page, 40 unsigned int from, unsigned int to) 41 { 42 struct buffer_head *head = page_buffers(page); 43 unsigned int bsize = head->b_size; 44 struct buffer_head *bh; 45 unsigned int start, end; 46 47 for (bh = head, start = 0; bh != head || !start; 48 bh = bh->b_this_page, start = end) { 49 end = start + bsize; 50 if (end <= from || start >= to) 51 continue; 52 if (gfs2_is_jdata(ip)) 53 set_buffer_uptodate(bh); 54 gfs2_trans_add_bh(ip->i_gl, bh, 0); 55 } 56 } 57 58 /** 59 * gfs2_get_block_noalloc - Fills in a buffer head with details about a block 60 * @inode: The inode 61 * @lblock: The block number to look up 62 * @bh_result: The buffer head to return the result in 63 * @create: Non-zero if we may add block to the file 64 * 65 * Returns: errno 66 */ 67 68 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock, 69 struct buffer_head *bh_result, int create) 70 { 71 int error; 72 73 error = gfs2_block_map(inode, lblock, bh_result, 0); 74 if (error) 75 return error; 76 if (!buffer_mapped(bh_result)) 77 return -EIO; 78 return 0; 79 } 80 81 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock, 82 struct buffer_head *bh_result, int create) 83 { 84 return gfs2_block_map(inode, lblock, bh_result, 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_CACHE_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_CACHE_SIZE-1); 111 if (page->index > end_index || (page->index == end_index && !offset)) { 112 page->mapping->a_ops->invalidatepage(page, 0); 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_writeback_writepage - Write page for writeback mappings 125 * @page: The page 126 * @wbc: The writeback control 127 * 128 */ 129 130 static int gfs2_writeback_writepage(struct page *page, 131 struct writeback_control *wbc) 132 { 133 int ret; 134 135 ret = gfs2_writepage_common(page, wbc); 136 if (ret <= 0) 137 return ret; 138 139 return nobh_writepage(page, gfs2_get_block_noalloc, wbc); 140 } 141 142 /** 143 * gfs2_ordered_writepage - Write page for ordered data files 144 * @page: The page to write 145 * @wbc: The writeback control 146 * 147 */ 148 149 static int gfs2_ordered_writepage(struct page *page, 150 struct writeback_control *wbc) 151 { 152 struct inode *inode = page->mapping->host; 153 struct gfs2_inode *ip = GFS2_I(inode); 154 int ret; 155 156 ret = gfs2_writepage_common(page, wbc); 157 if (ret <= 0) 158 return ret; 159 160 if (!page_has_buffers(page)) { 161 create_empty_buffers(page, inode->i_sb->s_blocksize, 162 (1 << BH_Dirty)|(1 << BH_Uptodate)); 163 } 164 gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1); 165 return block_write_full_page(page, gfs2_get_block_noalloc, wbc); 166 } 167 168 /** 169 * __gfs2_jdata_writepage - The core of jdata writepage 170 * @page: The page to write 171 * @wbc: The writeback control 172 * 173 * This is shared between writepage and writepages and implements the 174 * core of the writepage operation. If a transaction is required then 175 * PageChecked will have been set and the transaction will have 176 * already been started before this is called. 177 */ 178 179 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc) 180 { 181 struct inode *inode = page->mapping->host; 182 struct gfs2_inode *ip = GFS2_I(inode); 183 struct gfs2_sbd *sdp = GFS2_SB(inode); 184 185 if (PageChecked(page)) { 186 ClearPageChecked(page); 187 if (!page_has_buffers(page)) { 188 create_empty_buffers(page, inode->i_sb->s_blocksize, 189 (1 << BH_Dirty)|(1 << BH_Uptodate)); 190 } 191 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1); 192 } 193 return block_write_full_page(page, gfs2_get_block_noalloc, wbc); 194 } 195 196 /** 197 * gfs2_jdata_writepage - Write complete page 198 * @page: Page to write 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_sbd *sdp = GFS2_SB(inode); 208 int ret; 209 int done_trans = 0; 210 211 if (PageChecked(page)) { 212 if (wbc->sync_mode != WB_SYNC_ALL) 213 goto out_ignore; 214 ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0); 215 if (ret) 216 goto out_ignore; 217 done_trans = 1; 218 } 219 ret = gfs2_writepage_common(page, wbc); 220 if (ret > 0) 221 ret = __gfs2_jdata_writepage(page, wbc); 222 if (done_trans) 223 gfs2_trans_end(sdp); 224 return ret; 225 226 out_ignore: 227 redirty_page_for_writepage(wbc, page); 228 unlock_page(page); 229 return 0; 230 } 231 232 /** 233 * gfs2_writeback_writepages - Write a bunch of dirty pages back to disk 234 * @mapping: The mapping to write 235 * @wbc: Write-back control 236 * 237 * For the data=writeback case we can already ignore buffer heads 238 * and write whole extents at once. This is a big reduction in the 239 * number of I/O requests we send and the bmap calls we make in this case. 240 */ 241 static int gfs2_writeback_writepages(struct address_space *mapping, 242 struct writeback_control *wbc) 243 { 244 return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc); 245 } 246 247 /** 248 * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages 249 * @mapping: The mapping 250 * @wbc: The writeback control 251 * @writepage: The writepage function to call for each page 252 * @pvec: The vector of pages 253 * @nr_pages: The number of pages to write 254 * 255 * Returns: non-zero if loop should terminate, zero otherwise 256 */ 257 258 static int gfs2_write_jdata_pagevec(struct address_space *mapping, 259 struct writeback_control *wbc, 260 struct pagevec *pvec, 261 int nr_pages, pgoff_t end) 262 { 263 struct inode *inode = mapping->host; 264 struct gfs2_sbd *sdp = GFS2_SB(inode); 265 loff_t i_size = i_size_read(inode); 266 pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; 267 unsigned offset = i_size & (PAGE_CACHE_SIZE-1); 268 unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize); 269 int i; 270 int ret; 271 272 ret = gfs2_trans_begin(sdp, nrblocks, nrblocks); 273 if (ret < 0) 274 return ret; 275 276 for(i = 0; i < nr_pages; i++) { 277 struct page *page = pvec->pages[i]; 278 279 lock_page(page); 280 281 if (unlikely(page->mapping != mapping)) { 282 unlock_page(page); 283 continue; 284 } 285 286 if (!wbc->range_cyclic && page->index > end) { 287 ret = 1; 288 unlock_page(page); 289 continue; 290 } 291 292 if (wbc->sync_mode != WB_SYNC_NONE) 293 wait_on_page_writeback(page); 294 295 if (PageWriteback(page) || 296 !clear_page_dirty_for_io(page)) { 297 unlock_page(page); 298 continue; 299 } 300 301 /* Is the page fully outside i_size? (truncate in progress) */ 302 if (page->index > end_index || (page->index == end_index && !offset)) { 303 page->mapping->a_ops->invalidatepage(page, 0); 304 unlock_page(page); 305 continue; 306 } 307 308 ret = __gfs2_jdata_writepage(page, wbc); 309 310 if (ret || (--(wbc->nr_to_write) <= 0)) 311 ret = 1; 312 } 313 gfs2_trans_end(sdp); 314 return ret; 315 } 316 317 /** 318 * gfs2_write_cache_jdata - Like write_cache_pages but different 319 * @mapping: The mapping to write 320 * @wbc: The writeback control 321 * @writepage: The writepage function to call 322 * @data: The data to pass to writepage 323 * 324 * The reason that we use our own function here is that we need to 325 * start transactions before we grab page locks. This allows us 326 * to get the ordering right. 327 */ 328 329 static int gfs2_write_cache_jdata(struct address_space *mapping, 330 struct writeback_control *wbc) 331 { 332 int ret = 0; 333 int done = 0; 334 struct pagevec pvec; 335 int nr_pages; 336 pgoff_t index; 337 pgoff_t end; 338 int scanned = 0; 339 int range_whole = 0; 340 341 pagevec_init(&pvec, 0); 342 if (wbc->range_cyclic) { 343 index = mapping->writeback_index; /* Start from prev offset */ 344 end = -1; 345 } else { 346 index = wbc->range_start >> PAGE_CACHE_SHIFT; 347 end = wbc->range_end >> PAGE_CACHE_SHIFT; 348 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) 349 range_whole = 1; 350 scanned = 1; 351 } 352 353 retry: 354 while (!done && (index <= end) && 355 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, 356 PAGECACHE_TAG_DIRTY, 357 min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) { 358 scanned = 1; 359 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end); 360 if (ret) 361 done = 1; 362 if (ret > 0) 363 ret = 0; 364 365 pagevec_release(&pvec); 366 cond_resched(); 367 } 368 369 if (!scanned && !done) { 370 /* 371 * We hit the last page and there is more work to be done: wrap 372 * back to the start of the file 373 */ 374 scanned = 1; 375 index = 0; 376 goto retry; 377 } 378 379 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) 380 mapping->writeback_index = index; 381 return ret; 382 } 383 384 385 /** 386 * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk 387 * @mapping: The mapping to write 388 * @wbc: The writeback control 389 * 390 */ 391 392 static int gfs2_jdata_writepages(struct address_space *mapping, 393 struct writeback_control *wbc) 394 { 395 struct gfs2_inode *ip = GFS2_I(mapping->host); 396 struct gfs2_sbd *sdp = GFS2_SB(mapping->host); 397 int ret; 398 399 ret = gfs2_write_cache_jdata(mapping, wbc); 400 if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) { 401 gfs2_log_flush(sdp, ip->i_gl); 402 ret = gfs2_write_cache_jdata(mapping, wbc); 403 } 404 return ret; 405 } 406 407 /** 408 * stuffed_readpage - Fill in a Linux page with stuffed file data 409 * @ip: the inode 410 * @page: the page 411 * 412 * Returns: errno 413 */ 414 415 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page) 416 { 417 struct buffer_head *dibh; 418 u64 dsize = i_size_read(&ip->i_inode); 419 void *kaddr; 420 int error; 421 422 /* 423 * Due to the order of unstuffing files and ->fault(), we can be 424 * asked for a zero page in the case of a stuffed file being extended, 425 * so we need to supply one here. It doesn't happen often. 426 */ 427 if (unlikely(page->index)) { 428 zero_user(page, 0, PAGE_CACHE_SIZE); 429 SetPageUptodate(page); 430 return 0; 431 } 432 433 error = gfs2_meta_inode_buffer(ip, &dibh); 434 if (error) 435 return error; 436 437 kaddr = kmap_atomic(page, KM_USER0); 438 if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode))) 439 dsize = (dibh->b_size - sizeof(struct gfs2_dinode)); 440 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize); 441 memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize); 442 kunmap_atomic(kaddr, KM_USER0); 443 flush_dcache_page(page); 444 brelse(dibh); 445 SetPageUptodate(page); 446 447 return 0; 448 } 449 450 451 /** 452 * __gfs2_readpage - readpage 453 * @file: The file to read a page for 454 * @page: The page to read 455 * 456 * This is the core of gfs2's readpage. Its used by the internal file 457 * reading code as in that case we already hold the glock. Also its 458 * called by gfs2_readpage() once the required lock has been granted. 459 * 460 */ 461 462 static int __gfs2_readpage(void *file, struct page *page) 463 { 464 struct gfs2_inode *ip = GFS2_I(page->mapping->host); 465 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host); 466 int error; 467 468 if (gfs2_is_stuffed(ip)) { 469 error = stuffed_readpage(ip, page); 470 unlock_page(page); 471 } else { 472 error = mpage_readpage(page, gfs2_block_map); 473 } 474 475 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 476 return -EIO; 477 478 return error; 479 } 480 481 /** 482 * gfs2_readpage - read a page of a file 483 * @file: The file to read 484 * @page: The page of the file 485 * 486 * This deals with the locking required. We have to unlock and 487 * relock the page in order to get the locking in the right 488 * order. 489 */ 490 491 static int gfs2_readpage(struct file *file, struct page *page) 492 { 493 struct address_space *mapping = page->mapping; 494 struct gfs2_inode *ip = GFS2_I(mapping->host); 495 struct gfs2_holder gh; 496 int error; 497 498 unlock_page(page); 499 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); 500 error = gfs2_glock_nq(&gh); 501 if (unlikely(error)) 502 goto out; 503 error = AOP_TRUNCATED_PAGE; 504 lock_page(page); 505 if (page->mapping == mapping && !PageUptodate(page)) 506 error = __gfs2_readpage(file, page); 507 else 508 unlock_page(page); 509 gfs2_glock_dq(&gh); 510 out: 511 gfs2_holder_uninit(&gh); 512 if (error && error != AOP_TRUNCATED_PAGE) 513 lock_page(page); 514 return error; 515 } 516 517 /** 518 * gfs2_internal_read - read an internal file 519 * @ip: The gfs2 inode 520 * @ra_state: The readahead state (or NULL for no readahead) 521 * @buf: The buffer to fill 522 * @pos: The file position 523 * @size: The amount to read 524 * 525 */ 526 527 int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state, 528 char *buf, loff_t *pos, unsigned size) 529 { 530 struct address_space *mapping = ip->i_inode.i_mapping; 531 unsigned long index = *pos / PAGE_CACHE_SIZE; 532 unsigned offset = *pos & (PAGE_CACHE_SIZE - 1); 533 unsigned copied = 0; 534 unsigned amt; 535 struct page *page; 536 void *p; 537 538 do { 539 amt = size - copied; 540 if (offset + size > PAGE_CACHE_SIZE) 541 amt = PAGE_CACHE_SIZE - offset; 542 page = read_cache_page(mapping, index, __gfs2_readpage, NULL); 543 if (IS_ERR(page)) 544 return PTR_ERR(page); 545 p = kmap_atomic(page, KM_USER0); 546 memcpy(buf + copied, p + offset, amt); 547 kunmap_atomic(p, KM_USER0); 548 mark_page_accessed(page); 549 page_cache_release(page); 550 copied += amt; 551 index++; 552 offset = 0; 553 } while(copied < size); 554 (*pos) += size; 555 return size; 556 } 557 558 /** 559 * gfs2_readpages - Read a bunch of pages at once 560 * 561 * Some notes: 562 * 1. This is only for readahead, so we can simply ignore any things 563 * which are slightly inconvenient (such as locking conflicts between 564 * the page lock and the glock) and return having done no I/O. Its 565 * obviously not something we'd want to do on too regular a basis. 566 * Any I/O we ignore at this time will be done via readpage later. 567 * 2. We don't handle stuffed files here we let readpage do the honours. 568 * 3. mpage_readpages() does most of the heavy lifting in the common case. 569 * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places. 570 */ 571 572 static int gfs2_readpages(struct file *file, struct address_space *mapping, 573 struct list_head *pages, unsigned nr_pages) 574 { 575 struct inode *inode = mapping->host; 576 struct gfs2_inode *ip = GFS2_I(inode); 577 struct gfs2_sbd *sdp = GFS2_SB(inode); 578 struct gfs2_holder gh; 579 int ret; 580 581 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh); 582 ret = gfs2_glock_nq(&gh); 583 if (unlikely(ret)) 584 goto out_uninit; 585 if (!gfs2_is_stuffed(ip)) 586 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map); 587 gfs2_glock_dq(&gh); 588 out_uninit: 589 gfs2_holder_uninit(&gh); 590 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 591 ret = -EIO; 592 return ret; 593 } 594 595 /** 596 * gfs2_write_begin - Begin to write to a file 597 * @file: The file to write to 598 * @mapping: The mapping in which to write 599 * @pos: The file offset at which to start writing 600 * @len: Length of the write 601 * @flags: Various flags 602 * @pagep: Pointer to return the page 603 * @fsdata: Pointer to return fs data (unused by GFS2) 604 * 605 * Returns: errno 606 */ 607 608 static int gfs2_write_begin(struct file *file, struct address_space *mapping, 609 loff_t pos, unsigned len, unsigned flags, 610 struct page **pagep, void **fsdata) 611 { 612 struct gfs2_inode *ip = GFS2_I(mapping->host); 613 struct gfs2_sbd *sdp = GFS2_SB(mapping->host); 614 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); 615 unsigned int data_blocks = 0, ind_blocks = 0, rblocks; 616 int alloc_required; 617 int error = 0; 618 struct gfs2_alloc *al; 619 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 620 unsigned from = pos & (PAGE_CACHE_SIZE - 1); 621 unsigned to = from + len; 622 struct page *page; 623 624 gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh); 625 error = gfs2_glock_nq(&ip->i_gh); 626 if (unlikely(error)) 627 goto out_uninit; 628 if (&ip->i_inode == sdp->sd_rindex) { 629 error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, 630 GL_NOCACHE, &m_ip->i_gh); 631 if (unlikely(error)) { 632 gfs2_glock_dq(&ip->i_gh); 633 goto out_uninit; 634 } 635 } 636 637 alloc_required = gfs2_write_alloc_required(ip, pos, len); 638 639 if (alloc_required || gfs2_is_jdata(ip)) 640 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks); 641 642 if (alloc_required) { 643 al = gfs2_alloc_get(ip); 644 if (!al) { 645 error = -ENOMEM; 646 goto out_unlock; 647 } 648 649 error = gfs2_quota_lock_check(ip); 650 if (error) 651 goto out_alloc_put; 652 653 al->al_requested = data_blocks + ind_blocks; 654 error = gfs2_inplace_reserve(ip); 655 if (error) 656 goto out_qunlock; 657 } 658 659 rblocks = RES_DINODE + ind_blocks; 660 if (gfs2_is_jdata(ip)) 661 rblocks += data_blocks ? data_blocks : 1; 662 if (ind_blocks || data_blocks) 663 rblocks += RES_STATFS + RES_QUOTA; 664 if (&ip->i_inode == sdp->sd_rindex) 665 rblocks += 2 * RES_STATFS; 666 667 error = gfs2_trans_begin(sdp, rblocks, 668 PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize); 669 if (error) 670 goto out_trans_fail; 671 672 error = -ENOMEM; 673 flags |= AOP_FLAG_NOFS; 674 page = grab_cache_page_write_begin(mapping, index, flags); 675 *pagep = page; 676 if (unlikely(!page)) 677 goto out_endtrans; 678 679 if (gfs2_is_stuffed(ip)) { 680 error = 0; 681 if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) { 682 error = gfs2_unstuff_dinode(ip, page); 683 if (error == 0) 684 goto prepare_write; 685 } else if (!PageUptodate(page)) { 686 error = stuffed_readpage(ip, page); 687 } 688 goto out; 689 } 690 691 prepare_write: 692 error = block_prepare_write(page, from, to, gfs2_block_map); 693 out: 694 if (error == 0) 695 return 0; 696 697 page_cache_release(page); 698 699 gfs2_trans_end(sdp); 700 if (pos + len > ip->i_inode.i_size) 701 gfs2_trim_blocks(&ip->i_inode); 702 goto out_trans_fail; 703 704 out_endtrans: 705 gfs2_trans_end(sdp); 706 out_trans_fail: 707 if (alloc_required) { 708 gfs2_inplace_release(ip); 709 out_qunlock: 710 gfs2_quota_unlock(ip); 711 out_alloc_put: 712 gfs2_alloc_put(ip); 713 } 714 out_unlock: 715 if (&ip->i_inode == sdp->sd_rindex) { 716 gfs2_glock_dq(&m_ip->i_gh); 717 gfs2_holder_uninit(&m_ip->i_gh); 718 } 719 gfs2_glock_dq(&ip->i_gh); 720 out_uninit: 721 gfs2_holder_uninit(&ip->i_gh); 722 return error; 723 } 724 725 /** 726 * adjust_fs_space - Adjusts the free space available due to gfs2_grow 727 * @inode: the rindex inode 728 */ 729 static void adjust_fs_space(struct inode *inode) 730 { 731 struct gfs2_sbd *sdp = inode->i_sb->s_fs_info; 732 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); 733 struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode); 734 struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master; 735 struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local; 736 struct buffer_head *m_bh, *l_bh; 737 u64 fs_total, new_free; 738 739 /* Total up the file system space, according to the latest rindex. */ 740 fs_total = gfs2_ri_total(sdp); 741 if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0) 742 return; 743 744 spin_lock(&sdp->sd_statfs_spin); 745 gfs2_statfs_change_in(m_sc, m_bh->b_data + 746 sizeof(struct gfs2_dinode)); 747 if (fs_total > (m_sc->sc_total + l_sc->sc_total)) 748 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total); 749 else 750 new_free = 0; 751 spin_unlock(&sdp->sd_statfs_spin); 752 fs_warn(sdp, "File system extended by %llu blocks.\n", 753 (unsigned long long)new_free); 754 gfs2_statfs_change(sdp, new_free, new_free, 0); 755 756 if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0) 757 goto out; 758 update_statfs(sdp, m_bh, l_bh); 759 brelse(l_bh); 760 out: 761 brelse(m_bh); 762 } 763 764 /** 765 * gfs2_stuffed_write_end - Write end for stuffed files 766 * @inode: The inode 767 * @dibh: The buffer_head containing the on-disk inode 768 * @pos: The file position 769 * @len: The length of the write 770 * @copied: How much was actually copied by the VFS 771 * @page: The page 772 * 773 * This copies the data from the page into the inode block after 774 * the inode data structure itself. 775 * 776 * Returns: errno 777 */ 778 static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh, 779 loff_t pos, unsigned len, unsigned copied, 780 struct page *page) 781 { 782 struct gfs2_inode *ip = GFS2_I(inode); 783 struct gfs2_sbd *sdp = GFS2_SB(inode); 784 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); 785 u64 to = pos + copied; 786 void *kaddr; 787 unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode); 788 struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data; 789 790 BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode))); 791 kaddr = kmap_atomic(page, KM_USER0); 792 memcpy(buf + pos, kaddr + pos, copied); 793 memset(kaddr + pos + copied, 0, len - copied); 794 flush_dcache_page(page); 795 kunmap_atomic(kaddr, KM_USER0); 796 797 if (!PageUptodate(page)) 798 SetPageUptodate(page); 799 unlock_page(page); 800 page_cache_release(page); 801 802 if (copied) { 803 if (inode->i_size < to) 804 i_size_write(inode, to); 805 gfs2_dinode_out(ip, di); 806 mark_inode_dirty(inode); 807 } 808 809 if (inode == sdp->sd_rindex) { 810 adjust_fs_space(inode); 811 ip->i_gh.gh_flags |= GL_NOCACHE; 812 } 813 814 brelse(dibh); 815 gfs2_trans_end(sdp); 816 if (inode == sdp->sd_rindex) { 817 gfs2_glock_dq(&m_ip->i_gh); 818 gfs2_holder_uninit(&m_ip->i_gh); 819 } 820 gfs2_glock_dq(&ip->i_gh); 821 gfs2_holder_uninit(&ip->i_gh); 822 return copied; 823 } 824 825 /** 826 * gfs2_write_end 827 * @file: The file to write to 828 * @mapping: The address space to write to 829 * @pos: The file position 830 * @len: The length of the data 831 * @copied: 832 * @page: The page that has been written 833 * @fsdata: The fsdata (unused in GFS2) 834 * 835 * The main write_end function for GFS2. We have a separate one for 836 * stuffed files as they are slightly different, otherwise we just 837 * put our locking around the VFS provided functions. 838 * 839 * Returns: errno 840 */ 841 842 static int gfs2_write_end(struct file *file, struct address_space *mapping, 843 loff_t pos, unsigned len, unsigned copied, 844 struct page *page, void *fsdata) 845 { 846 struct inode *inode = page->mapping->host; 847 struct gfs2_inode *ip = GFS2_I(inode); 848 struct gfs2_sbd *sdp = GFS2_SB(inode); 849 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); 850 struct buffer_head *dibh; 851 struct gfs2_alloc *al = ip->i_alloc; 852 unsigned int from = pos & (PAGE_CACHE_SIZE - 1); 853 unsigned int to = from + len; 854 int ret; 855 856 BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL); 857 858 ret = gfs2_meta_inode_buffer(ip, &dibh); 859 if (unlikely(ret)) { 860 unlock_page(page); 861 page_cache_release(page); 862 goto failed; 863 } 864 865 gfs2_trans_add_bh(ip->i_gl, dibh, 1); 866 867 if (gfs2_is_stuffed(ip)) 868 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page); 869 870 if (!gfs2_is_writeback(ip)) 871 gfs2_page_add_databufs(ip, page, from, to); 872 873 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata); 874 if (ret > 0) { 875 gfs2_dinode_out(ip, dibh->b_data); 876 mark_inode_dirty(inode); 877 } 878 879 if (inode == sdp->sd_rindex) { 880 adjust_fs_space(inode); 881 ip->i_gh.gh_flags |= GL_NOCACHE; 882 } 883 884 brelse(dibh); 885 gfs2_trans_end(sdp); 886 failed: 887 if (al) { 888 gfs2_inplace_release(ip); 889 gfs2_quota_unlock(ip); 890 gfs2_alloc_put(ip); 891 } 892 if (inode == sdp->sd_rindex) { 893 gfs2_glock_dq(&m_ip->i_gh); 894 gfs2_holder_uninit(&m_ip->i_gh); 895 } 896 gfs2_glock_dq(&ip->i_gh); 897 gfs2_holder_uninit(&ip->i_gh); 898 return ret; 899 } 900 901 /** 902 * gfs2_set_page_dirty - Page dirtying function 903 * @page: The page to dirty 904 * 905 * Returns: 1 if it dirtyed the page, or 0 otherwise 906 */ 907 908 static int gfs2_set_page_dirty(struct page *page) 909 { 910 SetPageChecked(page); 911 return __set_page_dirty_buffers(page); 912 } 913 914 /** 915 * gfs2_bmap - Block map function 916 * @mapping: Address space info 917 * @lblock: The block to map 918 * 919 * Returns: The disk address for the block or 0 on hole or error 920 */ 921 922 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock) 923 { 924 struct gfs2_inode *ip = GFS2_I(mapping->host); 925 struct gfs2_holder i_gh; 926 sector_t dblock = 0; 927 int error; 928 929 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); 930 if (error) 931 return 0; 932 933 if (!gfs2_is_stuffed(ip)) 934 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map); 935 936 gfs2_glock_dq_uninit(&i_gh); 937 938 return dblock; 939 } 940 941 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh) 942 { 943 struct gfs2_bufdata *bd; 944 945 lock_buffer(bh); 946 gfs2_log_lock(sdp); 947 clear_buffer_dirty(bh); 948 bd = bh->b_private; 949 if (bd) { 950 if (!list_empty(&bd->bd_le.le_list) && !buffer_pinned(bh)) 951 list_del_init(&bd->bd_le.le_list); 952 else 953 gfs2_remove_from_journal(bh, current->journal_info, 0); 954 } 955 bh->b_bdev = NULL; 956 clear_buffer_mapped(bh); 957 clear_buffer_req(bh); 958 clear_buffer_new(bh); 959 gfs2_log_unlock(sdp); 960 unlock_buffer(bh); 961 } 962 963 static void gfs2_invalidatepage(struct page *page, unsigned long offset) 964 { 965 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host); 966 struct buffer_head *bh, *head; 967 unsigned long pos = 0; 968 969 BUG_ON(!PageLocked(page)); 970 if (offset == 0) 971 ClearPageChecked(page); 972 if (!page_has_buffers(page)) 973 goto out; 974 975 bh = head = page_buffers(page); 976 do { 977 if (offset <= pos) 978 gfs2_discard(sdp, bh); 979 pos += bh->b_size; 980 bh = bh->b_this_page; 981 } while (bh != head); 982 out: 983 if (offset == 0) 984 try_to_release_page(page, 0); 985 } 986 987 /** 988 * gfs2_ok_for_dio - check that dio is valid on this file 989 * @ip: The inode 990 * @rw: READ or WRITE 991 * @offset: The offset at which we are reading or writing 992 * 993 * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o) 994 * 1 (to accept the i/o request) 995 */ 996 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset) 997 { 998 /* 999 * Should we return an error here? I can't see that O_DIRECT for 1000 * a stuffed file makes any sense. For now we'll silently fall 1001 * back to buffered I/O 1002 */ 1003 if (gfs2_is_stuffed(ip)) 1004 return 0; 1005 1006 if (offset >= i_size_read(&ip->i_inode)) 1007 return 0; 1008 return 1; 1009 } 1010 1011 1012 1013 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb, 1014 const struct iovec *iov, loff_t offset, 1015 unsigned long nr_segs) 1016 { 1017 struct file *file = iocb->ki_filp; 1018 struct inode *inode = file->f_mapping->host; 1019 struct gfs2_inode *ip = GFS2_I(inode); 1020 struct gfs2_holder gh; 1021 int rv; 1022 1023 /* 1024 * Deferred lock, even if its a write, since we do no allocation 1025 * on this path. All we need change is atime, and this lock mode 1026 * ensures that other nodes have flushed their buffered read caches 1027 * (i.e. their page cache entries for this inode). We do not, 1028 * unfortunately have the option of only flushing a range like 1029 * the VFS does. 1030 */ 1031 gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh); 1032 rv = gfs2_glock_nq(&gh); 1033 if (rv) 1034 return rv; 1035 rv = gfs2_ok_for_dio(ip, rw, offset); 1036 if (rv != 1) 1037 goto out; /* dio not valid, fall back to buffered i/o */ 1038 1039 rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, 1040 offset, nr_segs, gfs2_get_block_direct, 1041 NULL, NULL, 0); 1042 out: 1043 gfs2_glock_dq_m(1, &gh); 1044 gfs2_holder_uninit(&gh); 1045 return rv; 1046 } 1047 1048 /** 1049 * gfs2_releasepage - free the metadata associated with a page 1050 * @page: the page that's being released 1051 * @gfp_mask: passed from Linux VFS, ignored by us 1052 * 1053 * Call try_to_free_buffers() if the buffers in this page can be 1054 * released. 1055 * 1056 * Returns: 0 1057 */ 1058 1059 int gfs2_releasepage(struct page *page, gfp_t gfp_mask) 1060 { 1061 struct address_space *mapping = page->mapping; 1062 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); 1063 struct buffer_head *bh, *head; 1064 struct gfs2_bufdata *bd; 1065 1066 if (!page_has_buffers(page)) 1067 return 0; 1068 1069 gfs2_log_lock(sdp); 1070 head = bh = page_buffers(page); 1071 do { 1072 if (atomic_read(&bh->b_count)) 1073 goto cannot_release; 1074 bd = bh->b_private; 1075 if (bd && bd->bd_ail) 1076 goto cannot_release; 1077 gfs2_assert_warn(sdp, !buffer_pinned(bh)); 1078 gfs2_assert_warn(sdp, !buffer_dirty(bh)); 1079 bh = bh->b_this_page; 1080 } while(bh != head); 1081 gfs2_log_unlock(sdp); 1082 1083 head = bh = page_buffers(page); 1084 do { 1085 gfs2_log_lock(sdp); 1086 bd = bh->b_private; 1087 if (bd) { 1088 gfs2_assert_warn(sdp, bd->bd_bh == bh); 1089 gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr)); 1090 if (!list_empty(&bd->bd_le.le_list)) { 1091 if (!buffer_pinned(bh)) 1092 list_del_init(&bd->bd_le.le_list); 1093 else 1094 bd = NULL; 1095 } 1096 if (bd) 1097 bd->bd_bh = NULL; 1098 bh->b_private = NULL; 1099 } 1100 gfs2_log_unlock(sdp); 1101 if (bd) 1102 kmem_cache_free(gfs2_bufdata_cachep, bd); 1103 1104 bh = bh->b_this_page; 1105 } while (bh != head); 1106 1107 return try_to_free_buffers(page); 1108 cannot_release: 1109 gfs2_log_unlock(sdp); 1110 return 0; 1111 } 1112 1113 static const struct address_space_operations gfs2_writeback_aops = { 1114 .writepage = gfs2_writeback_writepage, 1115 .writepages = gfs2_writeback_writepages, 1116 .readpage = gfs2_readpage, 1117 .readpages = gfs2_readpages, 1118 .sync_page = block_sync_page, 1119 .write_begin = gfs2_write_begin, 1120 .write_end = gfs2_write_end, 1121 .bmap = gfs2_bmap, 1122 .invalidatepage = gfs2_invalidatepage, 1123 .releasepage = gfs2_releasepage, 1124 .direct_IO = gfs2_direct_IO, 1125 .migratepage = buffer_migrate_page, 1126 .is_partially_uptodate = block_is_partially_uptodate, 1127 .error_remove_page = generic_error_remove_page, 1128 }; 1129 1130 static const struct address_space_operations gfs2_ordered_aops = { 1131 .writepage = gfs2_ordered_writepage, 1132 .readpage = gfs2_readpage, 1133 .readpages = gfs2_readpages, 1134 .sync_page = block_sync_page, 1135 .write_begin = gfs2_write_begin, 1136 .write_end = gfs2_write_end, 1137 .set_page_dirty = gfs2_set_page_dirty, 1138 .bmap = gfs2_bmap, 1139 .invalidatepage = gfs2_invalidatepage, 1140 .releasepage = gfs2_releasepage, 1141 .direct_IO = gfs2_direct_IO, 1142 .migratepage = buffer_migrate_page, 1143 .is_partially_uptodate = block_is_partially_uptodate, 1144 .error_remove_page = generic_error_remove_page, 1145 }; 1146 1147 static const struct address_space_operations gfs2_jdata_aops = { 1148 .writepage = gfs2_jdata_writepage, 1149 .writepages = gfs2_jdata_writepages, 1150 .readpage = gfs2_readpage, 1151 .readpages = gfs2_readpages, 1152 .sync_page = block_sync_page, 1153 .write_begin = gfs2_write_begin, 1154 .write_end = gfs2_write_end, 1155 .set_page_dirty = gfs2_set_page_dirty, 1156 .bmap = gfs2_bmap, 1157 .invalidatepage = gfs2_invalidatepage, 1158 .releasepage = gfs2_releasepage, 1159 .is_partially_uptodate = block_is_partially_uptodate, 1160 .error_remove_page = generic_error_remove_page, 1161 }; 1162 1163 void gfs2_set_aops(struct inode *inode) 1164 { 1165 struct gfs2_inode *ip = GFS2_I(inode); 1166 1167 if (gfs2_is_writeback(ip)) 1168 inode->i_mapping->a_ops = &gfs2_writeback_aops; 1169 else if (gfs2_is_ordered(ip)) 1170 inode->i_mapping->a_ops = &gfs2_ordered_aops; 1171 else if (gfs2_is_jdata(ip)) 1172 inode->i_mapping->a_ops = &gfs2_jdata_aops; 1173 else 1174 BUG(); 1175 } 1176 1177