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 34static 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(META_locked, &(mp)->flag) 43 44static inline void unlock_metapage(struct metapage *mp) 45{ 46 clear_bit(META_locked, &mp->flag); 47 wake_up(&mp->wait); 48} 49 50static 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 */ 70static 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 77static struct kmem_cache *metapage_cache; 78static mempool_t *metapage_mempool; 79 80#define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE) 81 82#if MPS_PER_PAGE > 1 83 84struct 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 91static inline struct metapage *page_to_mp(struct page *page, uint offset) 92{ 93 if (!PagePrivate(page)) 94 return NULL; 95 return mp_anchor(page)->mp[offset >> L2PSIZE]; 96} 97 98static 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 125static 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 144static inline void inc_io(struct page *page) 145{ 146 atomic_inc(&mp_anchor(page)->io_count); 147} 148 149static 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 156static inline struct metapage *page_to_mp(struct page *page, uint offset) 157{ 158 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL; 159} 160 161static 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 171static 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 183static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags) 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 197static inline struct metapage *alloc_metapage(gfp_t gfp_mask) 198{ 199 return mempool_alloc(metapage_mempool, gfp_mask); 200} 201 202static 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 210int __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, NULL); 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 231void metapage_exit(void) 232{ 233 mempool_destroy(metapage_mempool); 234 kmem_cache_destroy(metapage_cache); 235} 236 237static 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 251static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock, 252 unsigned 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 276static void last_read_complete(struct page *page) 277{ 278 if (!PageError(page)) 279 SetPageUptodate(page); 280 unlock_page(page); 281} 282 283static int metapage_read_end_io(struct bio *bio, unsigned int bytes_done, 284 int err) 285{ 286 struct page *page = bio->bi_private; 287 288 if (bio->bi_size) 289 return 1; 290 291 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) { 292 printk(KERN_ERR "metapage_read_end_io: I/O error\n"); 293 SetPageError(page); 294 } 295 296 dec_io(page, last_read_complete); 297 bio_put(bio); 298 299 return 0; 300} 301 302static void remove_from_logsync(struct metapage *mp) 303{ 304 struct jfs_log *log = mp->log; 305 unsigned long flags; 306/* 307 * This can race. Recheck that log hasn't been set to null, and after 308 * acquiring logsync lock, recheck lsn 309 */ 310 if (!log) 311 return; 312 313 LOGSYNC_LOCK(log, flags); 314 if (mp->lsn) { 315 mp->log = NULL; 316 mp->lsn = 0; 317 mp->clsn = 0; 318 log->count--; 319 list_del(&mp->synclist); 320 } 321 LOGSYNC_UNLOCK(log, flags); 322} 323 324static void last_write_complete(struct page *page) 325{ 326 struct metapage *mp; 327 unsigned int offset; 328 329 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 330 mp = page_to_mp(page, offset); 331 if (mp && test_bit(META_io, &mp->flag)) { 332 if (mp->lsn) 333 remove_from_logsync(mp); 334 clear_bit(META_io, &mp->flag); 335 } 336 /* 337 * I'd like to call drop_metapage here, but I don't think it's 338 * safe unless I have the page locked 339 */ 340 } 341 end_page_writeback(page); 342} 343 344static int metapage_write_end_io(struct bio *bio, unsigned int bytes_done, 345 int err) 346{ 347 struct page *page = bio->bi_private; 348 349 BUG_ON(!PagePrivate(page)); 350 351 if (bio->bi_size) 352 return 1; 353 354 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) { 355 printk(KERN_ERR "metapage_write_end_io: I/O error\n"); 356 SetPageError(page); 357 } 358 dec_io(page, last_write_complete); 359 bio_put(bio); 360 return 0; 361} 362 363static int metapage_writepage(struct page *page, struct writeback_control *wbc) 364{ 365 struct bio *bio = NULL; 366 unsigned int block_offset; /* block offset of mp within page */ 367 struct inode *inode = page->mapping->host; 368 unsigned int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage; 369 unsigned int len; 370 unsigned int xlen; 371 struct metapage *mp; 372 int redirty = 0; 373 sector_t lblock; 374 sector_t pblock; 375 sector_t next_block = 0; 376 sector_t page_start; 377 unsigned long bio_bytes = 0; 378 unsigned long bio_offset = 0; 379 unsigned int offset; 380 381 page_start = (sector_t)page->index << 382 (PAGE_CACHE_SHIFT - inode->i_blkbits); 383 BUG_ON(!PageLocked(page)); 384 BUG_ON(PageWriteback(page)); 385 386 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 387 mp = page_to_mp(page, offset); 388 389 if (!mp || !test_bit(META_dirty, &mp->flag)) 390 continue; 391 392 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) { 393 redirty = 1; 394 /* 395 * Make sure this page isn't blocked indefinitely. 396 * If the journal isn't undergoing I/O, push it 397 */ 398 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT)) 399 jfs_flush_journal(mp->log, 0); 400 continue; 401 } 402 403 clear_bit(META_dirty, &mp->flag); 404 block_offset = offset >> inode->i_blkbits; 405 lblock = page_start + block_offset; 406 if (bio) { 407 if (xlen && lblock == next_block) { 408 /* Contiguous, in memory & on disk */ 409 len = min(xlen, blocks_per_mp); 410 xlen -= len; 411 bio_bytes += len << inode->i_blkbits; 412 set_bit(META_io, &mp->flag); 413 continue; 414 } 415 /* Not contiguous */ 416 if (bio_add_page(bio, page, bio_bytes, bio_offset) < 417 bio_bytes) 418 goto add_failed; 419 /* 420 * Increment counter before submitting i/o to keep 421 * count from hitting zero before we're through 422 */ 423 inc_io(page); 424 if (!bio->bi_size) 425 goto dump_bio; 426 submit_bio(WRITE, bio); 427 bio = NULL; 428 } else { 429 set_page_writeback(page); 430 inc_io(page); 431 } 432 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits; 433 pblock = metapage_get_blocks(inode, lblock, &xlen); 434 if (!pblock) { 435 /* Need better error handling */ 436 printk(KERN_ERR "JFS: metapage_get_blocks failed\n"); 437 dec_io(page, last_write_complete); 438 continue; 439 } 440 set_bit(META_io, &mp->flag); 441 len = min(xlen, (uint) JFS_SBI(inode->i_sb)->nbperpage); 442 443 bio = bio_alloc(GFP_NOFS, 1); 444 bio->bi_bdev = inode->i_sb->s_bdev; 445 bio->bi_sector = pblock << (inode->i_blkbits - 9); 446 bio->bi_end_io = metapage_write_end_io; 447 bio->bi_private = page; 448 449 /* Don't call bio_add_page yet, we may add to this vec */ 450 bio_offset = offset; 451 bio_bytes = len << inode->i_blkbits; 452 453 xlen -= len; 454 next_block = lblock + len; 455 } 456 if (bio) { 457 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes) 458 goto add_failed; 459 if (!bio->bi_size) 460 goto dump_bio; 461 462 submit_bio(WRITE, bio); 463 } 464 if (redirty) 465 redirty_page_for_writepage(wbc, page); 466 467 unlock_page(page); 468 469 return 0; 470add_failed: 471 /* We should never reach here, since we're only adding one vec */ 472 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 473 goto skip; 474dump_bio: 475 dump_mem("bio", bio, sizeof(*bio)); 476skip: 477 bio_put(bio); 478 unlock_page(page); 479 dec_io(page, last_write_complete); 480 481 return -EIO; 482} 483 484static int metapage_readpage(struct file *fp, struct page *page) 485{ 486 struct inode *inode = page->mapping->host; 487 struct bio *bio = NULL; 488 unsigned int block_offset; 489 unsigned int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits; 490 sector_t page_start; /* address of page in fs blocks */ 491 sector_t pblock; 492 unsigned int xlen; 493 unsigned int len; 494 unsigned int offset; 495 496 BUG_ON(!PageLocked(page)); 497 page_start = (sector_t)page->index << 498 (PAGE_CACHE_SHIFT - inode->i_blkbits); 499 500 block_offset = 0; 501 while (block_offset < blocks_per_page) { 502 xlen = blocks_per_page - block_offset; 503 pblock = metapage_get_blocks(inode, page_start + block_offset, 504 &xlen); 505 if (pblock) { 506 if (!PagePrivate(page)) 507 insert_metapage(page, NULL); 508 inc_io(page); 509 if (bio) 510 submit_bio(READ, bio); 511 512 bio = bio_alloc(GFP_NOFS, 1); 513 bio->bi_bdev = inode->i_sb->s_bdev; 514 bio->bi_sector = 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 532add_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 539static int metapage_releasepage(struct page *page, gfp_t gfp_mask) 540{ 541 struct metapage *mp; 542 int ret = 1; 543 unsigned 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 568static void metapage_invalidatepage(struct page *page, unsigned long offset) 569{ 570 BUG_ON(offset); 571 572 BUG_ON(PageWriteback(page)); 573 574 metapage_releasepage(page, 0); 575} 576 577const struct address_space_operations jfs_metapage_aops = { 578 .readpage = metapage_readpage, 579 .writepage = metapage_writepage, 580 .sync_page = block_sync_page, 581 .releasepage = metapage_releasepage, 582 .invalidatepage = metapage_invalidatepage, 583 .set_page_dirty = __set_page_dirty_nobuffers, 584}; 585 586struct 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_metapage: mp->logical_size != size"); 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 "__get_metapage: using a " 656 "discarded metapage"); 657 discard_metapage(mp); 658 goto unlock; 659 } 660 clear_bit(META_discard, &mp->flag); 661 } 662 } else { 663 INCREMENT(mpStat.pagealloc); 664 mp = alloc_metapage(GFP_NOFS); 665 mp->page = page; 666 mp->flag = 0; 667 mp->xflag = COMMIT_PAGE; 668 mp->count = 1; 669 mp->nohomeok = 0; 670 mp->logical_size = size; 671 mp->data = page_address(page) + page_offset; 672 mp->index = lblock; 673 if (unlikely(insert_metapage(page, mp))) { 674 free_metapage(mp); 675 goto unlock; 676 } 677 lock_metapage(mp); 678 } 679 680 if (new) { 681 jfs_info("zeroing mp = 0x%p", mp); 682 memset(mp->data, 0, PSIZE); 683 } 684 685 unlock_page(page); 686 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data); 687 return mp; 688 689unlock: 690 unlock_page(page); 691 return NULL; 692} 693 694void grab_metapage(struct metapage * mp) 695{ 696 jfs_info("grab_metapage: mp = 0x%p", mp); 697 page_cache_get(mp->page); 698 lock_page(mp->page); 699 mp->count++; 700 lock_metapage(mp); 701 unlock_page(mp->page); 702} 703 704void force_metapage(struct metapage *mp) 705{ 706 struct page *page = mp->page; 707 jfs_info("force_metapage: mp = 0x%p", mp); 708 set_bit(META_forcewrite, &mp->flag); 709 clear_bit(META_sync, &mp->flag); 710 page_cache_get(page); 711 lock_page(page); 712 set_page_dirty(page); 713 write_one_page(page, 1); 714 clear_bit(META_forcewrite, &mp->flag); 715 page_cache_release(page); 716} 717 718void hold_metapage(struct metapage *mp) 719{ 720 lock_page(mp->page); 721} 722 723void put_metapage(struct metapage *mp) 724{ 725 if (mp->count || mp->nohomeok) { 726 /* Someone else will release this */ 727 unlock_page(mp->page); 728 return; 729 } 730 page_cache_get(mp->page); 731 mp->count++; 732 lock_metapage(mp); 733 unlock_page(mp->page); 734 release_metapage(mp); 735} 736 737void release_metapage(struct metapage * mp) 738{ 739 struct page *page = mp->page; 740 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag); 741 742 BUG_ON(!page); 743 744 lock_page(page); 745 unlock_metapage(mp); 746 747 assert(mp->count); 748 if (--mp->count || mp->nohomeok) { 749 unlock_page(page); 750 page_cache_release(page); 751 return; 752 } 753 754 if (test_bit(META_dirty, &mp->flag)) { 755 set_page_dirty(page); 756 if (test_bit(META_sync, &mp->flag)) { 757 clear_bit(META_sync, &mp->flag); 758 write_one_page(page, 1); 759 lock_page(page); /* write_one_page unlocks the page */ 760 } 761 } else if (mp->lsn) /* discard_metapage doesn't remove it */ 762 remove_from_logsync(mp); 763 764 /* Try to keep metapages from using up too much memory */ 765 drop_metapage(page, mp); 766 767 unlock_page(page); 768 page_cache_release(page); 769} 770 771void __invalidate_metapages(struct inode *ip, s64 addr, int len) 772{ 773 sector_t lblock; 774 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits; 775 int BlocksPerPage = 1 << l2BlocksPerPage; 776 /* All callers are interested in block device's mapping */ 777 struct address_space *mapping = 778 JFS_SBI(ip->i_sb)->direct_inode->i_mapping; 779 struct metapage *mp; 780 struct page *page; 781 unsigned int offset; 782 783 /* 784 * Mark metapages to discard. They will eventually be 785 * released, but should not be written. 786 */ 787 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len; 788 lblock += BlocksPerPage) { 789 page = find_lock_page(mapping, lblock >> l2BlocksPerPage); 790 if (!page) 791 continue; 792 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 793 mp = page_to_mp(page, offset); 794 if (!mp) 795 continue; 796 if (mp->index < addr) 797 continue; 798 if (mp->index >= addr + len) 799 break; 800 801 clear_bit(META_dirty, &mp->flag); 802 set_bit(META_discard, &mp->flag); 803 if (mp->lsn) 804 remove_from_logsync(mp); 805 } 806 unlock_page(page); 807 page_cache_release(page); 808 } 809} 810 811#ifdef CONFIG_JFS_STATISTICS 812int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length, 813 int *eof, void *data) 814{ 815 int len = 0; 816 off_t begin; 817 818 len += sprintf(buffer, 819 "JFS Metapage statistics\n" 820 "=======================\n" 821 "page allocations = %d\n" 822 "page frees = %d\n" 823 "lock waits = %d\n", 824 mpStat.pagealloc, 825 mpStat.pagefree, 826 mpStat.lockwait); 827 828 begin = offset; 829 *start = buffer + begin; 830 len -= begin; 831 832 if (len > length) 833 len = length; 834 else 835 *eof = 1; 836 837 if (len < 0) 838 len = 0; 839 840 return len; 841} 842#endif 843