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