1 /* 2 * Copyright (C) International Business Machines Corp., 2000-2005 3 * Portions Copyright (C) Christoph Hellwig, 2001-2002 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 13 * the GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 20 #include <linux/fs.h> 21 #include <linux/mm.h> 22 #include <linux/bio.h> 23 #include <linux/init.h> 24 #include <linux/buffer_head.h> 25 #include <linux/mempool.h> 26 #include "jfs_incore.h" 27 #include "jfs_superblock.h" 28 #include "jfs_filsys.h" 29 #include "jfs_metapage.h" 30 #include "jfs_txnmgr.h" 31 #include "jfs_debug.h" 32 33 #ifdef CONFIG_JFS_STATISTICS 34 static struct { 35 uint pagealloc; /* # of page allocations */ 36 uint pagefree; /* # of page frees */ 37 uint lockwait; /* # of sleeping lock_metapage() calls */ 38 } mpStat; 39 #endif 40 41 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag) 42 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag) 43 44 static inline void unlock_metapage(struct metapage *mp) 45 { 46 clear_bit_unlock(META_locked, &mp->flag); 47 wake_up(&mp->wait); 48 } 49 50 static inline void __lock_metapage(struct metapage *mp) 51 { 52 DECLARE_WAITQUEUE(wait, current); 53 INCREMENT(mpStat.lockwait); 54 add_wait_queue_exclusive(&mp->wait, &wait); 55 do { 56 set_current_state(TASK_UNINTERRUPTIBLE); 57 if (metapage_locked(mp)) { 58 unlock_page(mp->page); 59 io_schedule(); 60 lock_page(mp->page); 61 } 62 } while (trylock_metapage(mp)); 63 __set_current_state(TASK_RUNNING); 64 remove_wait_queue(&mp->wait, &wait); 65 } 66 67 /* 68 * Must have mp->page locked 69 */ 70 static inline void lock_metapage(struct metapage *mp) 71 { 72 if (trylock_metapage(mp)) 73 __lock_metapage(mp); 74 } 75 76 #define METAPOOL_MIN_PAGES 32 77 static struct kmem_cache *metapage_cache; 78 static mempool_t *metapage_mempool; 79 80 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE) 81 82 #if MPS_PER_PAGE > 1 83 84 struct meta_anchor { 85 int mp_count; 86 atomic_t io_count; 87 struct metapage *mp[MPS_PER_PAGE]; 88 }; 89 #define mp_anchor(page) ((struct meta_anchor *)page_private(page)) 90 91 static inline struct metapage *page_to_mp(struct page *page, int offset) 92 { 93 if (!PagePrivate(page)) 94 return NULL; 95 return mp_anchor(page)->mp[offset >> L2PSIZE]; 96 } 97 98 static inline int insert_metapage(struct page *page, struct metapage *mp) 99 { 100 struct meta_anchor *a; 101 int index; 102 int l2mp_blocks; /* log2 blocks per metapage */ 103 104 if (PagePrivate(page)) 105 a = mp_anchor(page); 106 else { 107 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS); 108 if (!a) 109 return -ENOMEM; 110 set_page_private(page, (unsigned long)a); 111 SetPagePrivate(page); 112 kmap(page); 113 } 114 115 if (mp) { 116 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits; 117 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1); 118 a->mp_count++; 119 a->mp[index] = mp; 120 } 121 122 return 0; 123 } 124 125 static inline void remove_metapage(struct page *page, struct metapage *mp) 126 { 127 struct meta_anchor *a = mp_anchor(page); 128 int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits; 129 int index; 130 131 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1); 132 133 BUG_ON(a->mp[index] != mp); 134 135 a->mp[index] = NULL; 136 if (--a->mp_count == 0) { 137 kfree(a); 138 set_page_private(page, 0); 139 ClearPagePrivate(page); 140 kunmap(page); 141 } 142 } 143 144 static inline void inc_io(struct page *page) 145 { 146 atomic_inc(&mp_anchor(page)->io_count); 147 } 148 149 static inline void dec_io(struct page *page, void (*handler) (struct page *)) 150 { 151 if (atomic_dec_and_test(&mp_anchor(page)->io_count)) 152 handler(page); 153 } 154 155 #else 156 static inline struct metapage *page_to_mp(struct page *page, int offset) 157 { 158 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL; 159 } 160 161 static inline int insert_metapage(struct page *page, struct metapage *mp) 162 { 163 if (mp) { 164 set_page_private(page, (unsigned long)mp); 165 SetPagePrivate(page); 166 kmap(page); 167 } 168 return 0; 169 } 170 171 static inline void remove_metapage(struct page *page, struct metapage *mp) 172 { 173 set_page_private(page, 0); 174 ClearPagePrivate(page); 175 kunmap(page); 176 } 177 178 #define inc_io(page) do {} while(0) 179 #define dec_io(page, handler) handler(page) 180 181 #endif 182 183 static void init_once(struct kmem_cache *cachep, void *foo) 184 { 185 struct metapage *mp = (struct metapage *)foo; 186 187 mp->lid = 0; 188 mp->lsn = 0; 189 mp->flag = 0; 190 mp->data = NULL; 191 mp->clsn = 0; 192 mp->log = NULL; 193 set_bit(META_free, &mp->flag); 194 init_waitqueue_head(&mp->wait); 195 } 196 197 static inline struct metapage *alloc_metapage(gfp_t gfp_mask) 198 { 199 return mempool_alloc(metapage_mempool, gfp_mask); 200 } 201 202 static inline void free_metapage(struct metapage *mp) 203 { 204 mp->flag = 0; 205 set_bit(META_free, &mp->flag); 206 207 mempool_free(mp, metapage_mempool); 208 } 209 210 int __init metapage_init(void) 211 { 212 /* 213 * Allocate the metapage structures 214 */ 215 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage), 216 0, 0, init_once); 217 if (metapage_cache == NULL) 218 return -ENOMEM; 219 220 metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES, 221 metapage_cache); 222 223 if (metapage_mempool == NULL) { 224 kmem_cache_destroy(metapage_cache); 225 return -ENOMEM; 226 } 227 228 return 0; 229 } 230 231 void metapage_exit(void) 232 { 233 mempool_destroy(metapage_mempool); 234 kmem_cache_destroy(metapage_cache); 235 } 236 237 static inline void drop_metapage(struct page *page, struct metapage *mp) 238 { 239 if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) || 240 test_bit(META_io, &mp->flag)) 241 return; 242 remove_metapage(page, mp); 243 INCREMENT(mpStat.pagefree); 244 free_metapage(mp); 245 } 246 247 /* 248 * Metapage address space operations 249 */ 250 251 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock, 252 int *len) 253 { 254 int rc = 0; 255 int xflag; 256 s64 xaddr; 257 sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 258 inode->i_blkbits; 259 260 if (lblock >= file_blocks) 261 return 0; 262 if (lblock + *len > file_blocks) 263 *len = file_blocks - lblock; 264 265 if (inode->i_ino) { 266 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0); 267 if ((rc == 0) && *len) 268 lblock = (sector_t)xaddr; 269 else 270 lblock = 0; 271 } /* else no mapping */ 272 273 return lblock; 274 } 275 276 static void last_read_complete(struct page *page) 277 { 278 if (!PageError(page)) 279 SetPageUptodate(page); 280 unlock_page(page); 281 } 282 283 static void metapage_read_end_io(struct bio *bio, int err) 284 { 285 struct page *page = bio->bi_private; 286 287 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) { 288 printk(KERN_ERR "metapage_read_end_io: I/O error\n"); 289 SetPageError(page); 290 } 291 292 dec_io(page, last_read_complete); 293 bio_put(bio); 294 } 295 296 static void remove_from_logsync(struct metapage *mp) 297 { 298 struct jfs_log *log = mp->log; 299 unsigned long flags; 300 /* 301 * This can race. Recheck that log hasn't been set to null, and after 302 * acquiring logsync lock, recheck lsn 303 */ 304 if (!log) 305 return; 306 307 LOGSYNC_LOCK(log, flags); 308 if (mp->lsn) { 309 mp->log = NULL; 310 mp->lsn = 0; 311 mp->clsn = 0; 312 log->count--; 313 list_del(&mp->synclist); 314 } 315 LOGSYNC_UNLOCK(log, flags); 316 } 317 318 static void last_write_complete(struct page *page) 319 { 320 struct metapage *mp; 321 unsigned int offset; 322 323 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 324 mp = page_to_mp(page, offset); 325 if (mp && test_bit(META_io, &mp->flag)) { 326 if (mp->lsn) 327 remove_from_logsync(mp); 328 clear_bit(META_io, &mp->flag); 329 } 330 /* 331 * I'd like to call drop_metapage here, but I don't think it's 332 * safe unless I have the page locked 333 */ 334 } 335 end_page_writeback(page); 336 } 337 338 static void metapage_write_end_io(struct bio *bio, int err) 339 { 340 struct page *page = bio->bi_private; 341 342 BUG_ON(!PagePrivate(page)); 343 344 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) { 345 printk(KERN_ERR "metapage_write_end_io: I/O error\n"); 346 SetPageError(page); 347 } 348 dec_io(page, last_write_complete); 349 bio_put(bio); 350 } 351 352 static int metapage_writepage(struct page *page, struct writeback_control *wbc) 353 { 354 struct bio *bio = NULL; 355 int block_offset; /* block offset of mp within page */ 356 struct inode *inode = page->mapping->host; 357 int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage; 358 int len; 359 int xlen; 360 struct metapage *mp; 361 int redirty = 0; 362 sector_t lblock; 363 int nr_underway = 0; 364 sector_t pblock; 365 sector_t next_block = 0; 366 sector_t page_start; 367 unsigned long bio_bytes = 0; 368 unsigned long bio_offset = 0; 369 int offset; 370 371 page_start = (sector_t)page->index << 372 (PAGE_CACHE_SHIFT - inode->i_blkbits); 373 BUG_ON(!PageLocked(page)); 374 BUG_ON(PageWriteback(page)); 375 set_page_writeback(page); 376 377 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 378 mp = page_to_mp(page, offset); 379 380 if (!mp || !test_bit(META_dirty, &mp->flag)) 381 continue; 382 383 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) { 384 redirty = 1; 385 /* 386 * Make sure this page isn't blocked indefinitely. 387 * If the journal isn't undergoing I/O, push it 388 */ 389 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT)) 390 jfs_flush_journal(mp->log, 0); 391 continue; 392 } 393 394 clear_bit(META_dirty, &mp->flag); 395 block_offset = offset >> inode->i_blkbits; 396 lblock = page_start + block_offset; 397 if (bio) { 398 if (xlen && lblock == next_block) { 399 /* Contiguous, in memory & on disk */ 400 len = min(xlen, blocks_per_mp); 401 xlen -= len; 402 bio_bytes += len << inode->i_blkbits; 403 set_bit(META_io, &mp->flag); 404 continue; 405 } 406 /* Not contiguous */ 407 if (bio_add_page(bio, page, bio_bytes, bio_offset) < 408 bio_bytes) 409 goto add_failed; 410 /* 411 * Increment counter before submitting i/o to keep 412 * count from hitting zero before we're through 413 */ 414 inc_io(page); 415 if (!bio->bi_size) 416 goto dump_bio; 417 submit_bio(WRITE, bio); 418 nr_underway++; 419 bio = NULL; 420 } else 421 inc_io(page); 422 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits; 423 pblock = metapage_get_blocks(inode, lblock, &xlen); 424 if (!pblock) { 425 /* Need better error handling */ 426 printk(KERN_ERR "JFS: metapage_get_blocks failed\n"); 427 dec_io(page, last_write_complete); 428 continue; 429 } 430 set_bit(META_io, &mp->flag); 431 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage); 432 433 bio = bio_alloc(GFP_NOFS, 1); 434 bio->bi_bdev = inode->i_sb->s_bdev; 435 bio->bi_sector = pblock << (inode->i_blkbits - 9); 436 bio->bi_end_io = metapage_write_end_io; 437 bio->bi_private = page; 438 439 /* Don't call bio_add_page yet, we may add to this vec */ 440 bio_offset = offset; 441 bio_bytes = len << inode->i_blkbits; 442 443 xlen -= len; 444 next_block = lblock + len; 445 } 446 if (bio) { 447 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes) 448 goto add_failed; 449 if (!bio->bi_size) 450 goto dump_bio; 451 452 submit_bio(WRITE, bio); 453 nr_underway++; 454 } 455 if (redirty) 456 redirty_page_for_writepage(wbc, page); 457 458 unlock_page(page); 459 460 if (nr_underway == 0) 461 end_page_writeback(page); 462 463 return 0; 464 add_failed: 465 /* We should never reach here, since we're only adding one vec */ 466 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 467 goto skip; 468 dump_bio: 469 print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16, 470 4, bio, sizeof(*bio), 0); 471 skip: 472 bio_put(bio); 473 unlock_page(page); 474 dec_io(page, last_write_complete); 475 476 return -EIO; 477 } 478 479 static int metapage_readpage(struct file *fp, struct page *page) 480 { 481 struct inode *inode = page->mapping->host; 482 struct bio *bio = NULL; 483 int block_offset; 484 int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits; 485 sector_t page_start; /* address of page in fs blocks */ 486 sector_t pblock; 487 int xlen; 488 unsigned int len; 489 int offset; 490 491 BUG_ON(!PageLocked(page)); 492 page_start = (sector_t)page->index << 493 (PAGE_CACHE_SHIFT - inode->i_blkbits); 494 495 block_offset = 0; 496 while (block_offset < blocks_per_page) { 497 xlen = blocks_per_page - block_offset; 498 pblock = metapage_get_blocks(inode, page_start + block_offset, 499 &xlen); 500 if (pblock) { 501 if (!PagePrivate(page)) 502 insert_metapage(page, NULL); 503 inc_io(page); 504 if (bio) 505 submit_bio(READ, bio); 506 507 bio = bio_alloc(GFP_NOFS, 1); 508 bio->bi_bdev = inode->i_sb->s_bdev; 509 bio->bi_sector = pblock << (inode->i_blkbits - 9); 510 bio->bi_end_io = metapage_read_end_io; 511 bio->bi_private = page; 512 len = xlen << inode->i_blkbits; 513 offset = block_offset << inode->i_blkbits; 514 if (bio_add_page(bio, page, len, offset) < len) 515 goto add_failed; 516 block_offset += xlen; 517 } else 518 block_offset++; 519 } 520 if (bio) 521 submit_bio(READ, bio); 522 else 523 unlock_page(page); 524 525 return 0; 526 527 add_failed: 528 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 529 bio_put(bio); 530 dec_io(page, last_read_complete); 531 return -EIO; 532 } 533 534 static int metapage_releasepage(struct page *page, gfp_t gfp_mask) 535 { 536 struct metapage *mp; 537 int ret = 1; 538 int offset; 539 540 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 541 mp = page_to_mp(page, offset); 542 543 if (!mp) 544 continue; 545 546 jfs_info("metapage_releasepage: mp = 0x%p", mp); 547 if (mp->count || mp->nohomeok || 548 test_bit(META_dirty, &mp->flag)) { 549 jfs_info("count = %ld, nohomeok = %d", mp->count, 550 mp->nohomeok); 551 ret = 0; 552 continue; 553 } 554 if (mp->lsn) 555 remove_from_logsync(mp); 556 remove_metapage(page, mp); 557 INCREMENT(mpStat.pagefree); 558 free_metapage(mp); 559 } 560 return ret; 561 } 562 563 static void metapage_invalidatepage(struct page *page, unsigned long offset) 564 { 565 BUG_ON(offset); 566 567 BUG_ON(PageWriteback(page)); 568 569 metapage_releasepage(page, 0); 570 } 571 572 const struct address_space_operations jfs_metapage_aops = { 573 .readpage = metapage_readpage, 574 .writepage = metapage_writepage, 575 .sync_page = block_sync_page, 576 .releasepage = metapage_releasepage, 577 .invalidatepage = metapage_invalidatepage, 578 .set_page_dirty = __set_page_dirty_nobuffers, 579 }; 580 581 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock, 582 unsigned int size, int absolute, 583 unsigned long new) 584 { 585 int l2BlocksPerPage; 586 int l2bsize; 587 struct address_space *mapping; 588 struct metapage *mp = NULL; 589 struct page *page; 590 unsigned long page_index; 591 unsigned long page_offset; 592 593 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d", 594 inode->i_ino, lblock, absolute); 595 596 l2bsize = inode->i_blkbits; 597 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize; 598 page_index = lblock >> l2BlocksPerPage; 599 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize; 600 if ((page_offset + size) > PAGE_CACHE_SIZE) { 601 jfs_err("MetaData crosses page boundary!!"); 602 jfs_err("lblock = %lx, size = %d", lblock, size); 603 dump_stack(); 604 return NULL; 605 } 606 if (absolute) 607 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping; 608 else { 609 /* 610 * If an nfs client tries to read an inode that is larger 611 * than any existing inodes, we may try to read past the 612 * end of the inode map 613 */ 614 if ((lblock << inode->i_blkbits) >= inode->i_size) 615 return NULL; 616 mapping = inode->i_mapping; 617 } 618 619 if (new && (PSIZE == PAGE_CACHE_SIZE)) { 620 page = grab_cache_page(mapping, page_index); 621 if (!page) { 622 jfs_err("grab_cache_page failed!"); 623 return NULL; 624 } 625 SetPageUptodate(page); 626 } else { 627 page = read_mapping_page(mapping, page_index, NULL); 628 if (IS_ERR(page) || !PageUptodate(page)) { 629 jfs_err("read_mapping_page failed!"); 630 return NULL; 631 } 632 lock_page(page); 633 } 634 635 mp = page_to_mp(page, page_offset); 636 if (mp) { 637 if (mp->logical_size != size) { 638 jfs_error(inode->i_sb, 639 "__get_metapage: mp->logical_size != size"); 640 jfs_err("logical_size = %d, size = %d", 641 mp->logical_size, size); 642 dump_stack(); 643 goto unlock; 644 } 645 mp->count++; 646 lock_metapage(mp); 647 if (test_bit(META_discard, &mp->flag)) { 648 if (!new) { 649 jfs_error(inode->i_sb, 650 "__get_metapage: using a " 651 "discarded metapage"); 652 discard_metapage(mp); 653 goto unlock; 654 } 655 clear_bit(META_discard, &mp->flag); 656 } 657 } else { 658 INCREMENT(mpStat.pagealloc); 659 mp = alloc_metapage(GFP_NOFS); 660 mp->page = page; 661 mp->flag = 0; 662 mp->xflag = COMMIT_PAGE; 663 mp->count = 1; 664 mp->nohomeok = 0; 665 mp->logical_size = size; 666 mp->data = page_address(page) + page_offset; 667 mp->index = lblock; 668 if (unlikely(insert_metapage(page, mp))) { 669 free_metapage(mp); 670 goto unlock; 671 } 672 lock_metapage(mp); 673 } 674 675 if (new) { 676 jfs_info("zeroing mp = 0x%p", mp); 677 memset(mp->data, 0, PSIZE); 678 } 679 680 unlock_page(page); 681 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data); 682 return mp; 683 684 unlock: 685 unlock_page(page); 686 return NULL; 687 } 688 689 void grab_metapage(struct metapage * mp) 690 { 691 jfs_info("grab_metapage: mp = 0x%p", mp); 692 page_cache_get(mp->page); 693 lock_page(mp->page); 694 mp->count++; 695 lock_metapage(mp); 696 unlock_page(mp->page); 697 } 698 699 void force_metapage(struct metapage *mp) 700 { 701 struct page *page = mp->page; 702 jfs_info("force_metapage: mp = 0x%p", mp); 703 set_bit(META_forcewrite, &mp->flag); 704 clear_bit(META_sync, &mp->flag); 705 page_cache_get(page); 706 lock_page(page); 707 set_page_dirty(page); 708 write_one_page(page, 1); 709 clear_bit(META_forcewrite, &mp->flag); 710 page_cache_release(page); 711 } 712 713 void hold_metapage(struct metapage *mp) 714 { 715 lock_page(mp->page); 716 } 717 718 void put_metapage(struct metapage *mp) 719 { 720 if (mp->count || mp->nohomeok) { 721 /* Someone else will release this */ 722 unlock_page(mp->page); 723 return; 724 } 725 page_cache_get(mp->page); 726 mp->count++; 727 lock_metapage(mp); 728 unlock_page(mp->page); 729 release_metapage(mp); 730 } 731 732 void release_metapage(struct metapage * mp) 733 { 734 struct page *page = mp->page; 735 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag); 736 737 BUG_ON(!page); 738 739 lock_page(page); 740 unlock_metapage(mp); 741 742 assert(mp->count); 743 if (--mp->count || mp->nohomeok) { 744 unlock_page(page); 745 page_cache_release(page); 746 return; 747 } 748 749 if (test_bit(META_dirty, &mp->flag)) { 750 set_page_dirty(page); 751 if (test_bit(META_sync, &mp->flag)) { 752 clear_bit(META_sync, &mp->flag); 753 write_one_page(page, 1); 754 lock_page(page); /* write_one_page unlocks the page */ 755 } 756 } else if (mp->lsn) /* discard_metapage doesn't remove it */ 757 remove_from_logsync(mp); 758 759 /* Try to keep metapages from using up too much memory */ 760 drop_metapage(page, mp); 761 762 unlock_page(page); 763 page_cache_release(page); 764 } 765 766 void __invalidate_metapages(struct inode *ip, s64 addr, int len) 767 { 768 sector_t lblock; 769 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits; 770 int BlocksPerPage = 1 << l2BlocksPerPage; 771 /* All callers are interested in block device's mapping */ 772 struct address_space *mapping = 773 JFS_SBI(ip->i_sb)->direct_inode->i_mapping; 774 struct metapage *mp; 775 struct page *page; 776 unsigned int offset; 777 778 /* 779 * Mark metapages to discard. They will eventually be 780 * released, but should not be written. 781 */ 782 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len; 783 lblock += BlocksPerPage) { 784 page = find_lock_page(mapping, lblock >> l2BlocksPerPage); 785 if (!page) 786 continue; 787 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 788 mp = page_to_mp(page, offset); 789 if (!mp) 790 continue; 791 if (mp->index < addr) 792 continue; 793 if (mp->index >= addr + len) 794 break; 795 796 clear_bit(META_dirty, &mp->flag); 797 set_bit(META_discard, &mp->flag); 798 if (mp->lsn) 799 remove_from_logsync(mp); 800 } 801 unlock_page(page); 802 page_cache_release(page); 803 } 804 } 805 806 #ifdef CONFIG_JFS_STATISTICS 807 int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length, 808 int *eof, void *data) 809 { 810 int len = 0; 811 off_t begin; 812 813 len += sprintf(buffer, 814 "JFS Metapage statistics\n" 815 "=======================\n" 816 "page allocations = %d\n" 817 "page frees = %d\n" 818 "lock waits = %d\n", 819 mpStat.pagealloc, 820 mpStat.pagefree, 821 mpStat.lockwait); 822 823 begin = offset; 824 *start = buffer + begin; 825 len -= begin; 826 827 if (len > length) 828 len = length; 829 else 830 *eof = 1; 831 832 if (len < 0) 833 len = 0; 834 835 return len; 836 } 837 #endif 838