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 37static 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 47static inline void unlock_metapage(struct metapage *mp) 48{ 49 clear_bit_unlock(META_locked, &mp->flag); 50 wake_up(&mp->wait); 51} 52 53static 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 */ 73static 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 80static struct kmem_cache *metapage_cache; 81static mempool_t *metapage_mempool; 82 83#define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE) 84 85#if MPS_PER_PAGE > 1 86 87struct 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 94static 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 101static 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 128static 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 147static inline void inc_io(struct page *page) 148{ 149 atomic_inc(&mp_anchor(page)->io_count); 150} 151 152static 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 159static inline struct metapage *page_to_mp(struct page *page, int offset) 160{ 161 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL; 162} 163 164static 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 174static 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 186static void init_once(void *foo) 187{ 188 struct metapage *mp = (struct metapage *)foo; 189 190 mp->lid = 0; 191 mp->lsn = 0; 192 mp->flag = 0; 193 mp->data = NULL; 194 mp->clsn = 0; 195 mp->log = NULL; 196 set_bit(META_free, &mp->flag); 197 init_waitqueue_head(&mp->wait); 198} 199 200static inline struct metapage *alloc_metapage(gfp_t gfp_mask) 201{ 202 return mempool_alloc(metapage_mempool, gfp_mask); 203} 204 205static inline void free_metapage(struct metapage *mp) 206{ 207 mp->flag = 0; 208 set_bit(META_free, &mp->flag); 209 210 mempool_free(mp, metapage_mempool); 211} 212 213int __init metapage_init(void) 214{ 215 /* 216 * Allocate the metapage structures 217 */ 218 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage), 219 0, 0, init_once); 220 if (metapage_cache == NULL) 221 return -ENOMEM; 222 223 metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES, 224 metapage_cache); 225 226 if (metapage_mempool == NULL) { 227 kmem_cache_destroy(metapage_cache); 228 return -ENOMEM; 229 } 230 231 return 0; 232} 233 234void metapage_exit(void) 235{ 236 mempool_destroy(metapage_mempool); 237 kmem_cache_destroy(metapage_cache); 238} 239 240static inline void drop_metapage(struct page *page, struct metapage *mp) 241{ 242 if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) || 243 test_bit(META_io, &mp->flag)) 244 return; 245 remove_metapage(page, mp); 246 INCREMENT(mpStat.pagefree); 247 free_metapage(mp); 248} 249 250/* 251 * Metapage address space operations 252 */ 253 254static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock, 255 int *len) 256{ 257 int rc = 0; 258 int xflag; 259 s64 xaddr; 260 sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 261 inode->i_blkbits; 262 263 if (lblock >= file_blocks) 264 return 0; 265 if (lblock + *len > file_blocks) 266 *len = file_blocks - lblock; 267 268 if (inode->i_ino) { 269 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0); 270 if ((rc == 0) && *len) 271 lblock = (sector_t)xaddr; 272 else 273 lblock = 0; 274 } /* else no mapping */ 275 276 return lblock; 277} 278 279static void last_read_complete(struct page *page) 280{ 281 if (!PageError(page)) 282 SetPageUptodate(page); 283 unlock_page(page); 284} 285 286static void metapage_read_end_io(struct bio *bio, int err) 287{ 288 struct page *page = bio->bi_private; 289 290 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) { 291 printk(KERN_ERR "metapage_read_end_io: I/O error\n"); 292 SetPageError(page); 293 } 294 295 dec_io(page, last_read_complete); 296 bio_put(bio); 297} 298 299static void remove_from_logsync(struct metapage *mp) 300{ 301 struct jfs_log *log = mp->log; 302 unsigned long flags; 303/* 304 * This can race. Recheck that log hasn't been set to null, and after 305 * acquiring logsync lock, recheck lsn 306 */ 307 if (!log) 308 return; 309 310 LOGSYNC_LOCK(log, flags); 311 if (mp->lsn) { 312 mp->log = NULL; 313 mp->lsn = 0; 314 mp->clsn = 0; 315 log->count--; 316 list_del(&mp->synclist); 317 } 318 LOGSYNC_UNLOCK(log, flags); 319} 320 321static void last_write_complete(struct page *page) 322{ 323 struct metapage *mp; 324 unsigned int offset; 325 326 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 327 mp = page_to_mp(page, offset); 328 if (mp && test_bit(META_io, &mp->flag)) { 329 if (mp->lsn) 330 remove_from_logsync(mp); 331 clear_bit(META_io, &mp->flag); 332 } 333 /* 334 * I'd like to call drop_metapage here, but I don't think it's 335 * safe unless I have the page locked 336 */ 337 } 338 end_page_writeback(page); 339} 340 341static void metapage_write_end_io(struct bio *bio, int err) 342{ 343 struct page *page = bio->bi_private; 344 345 BUG_ON(!PagePrivate(page)); 346 347 if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) { 348 printk(KERN_ERR "metapage_write_end_io: I/O error\n"); 349 SetPageError(page); 350 } 351 dec_io(page, last_write_complete); 352 bio_put(bio); 353} 354 355static int metapage_writepage(struct page *page, struct writeback_control *wbc) 356{ 357 struct bio *bio = NULL; 358 int block_offset; /* block offset of mp within page */ 359 struct inode *inode = page->mapping->host; 360 int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage; 361 int len; 362 int xlen; 363 struct metapage *mp; 364 int redirty = 0; 365 sector_t lblock; 366 int nr_underway = 0; 367 sector_t pblock; 368 sector_t next_block = 0; 369 sector_t page_start; 370 unsigned long bio_bytes = 0; 371 unsigned long bio_offset = 0; 372 int offset; 373 int bad_blocks = 0; 374 375 page_start = (sector_t)page->index << 376 (PAGE_CACHE_SHIFT - inode->i_blkbits); 377 BUG_ON(!PageLocked(page)); 378 BUG_ON(PageWriteback(page)); 379 set_page_writeback(page); 380 381 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 382 mp = page_to_mp(page, offset); 383 384 if (!mp || !test_bit(META_dirty, &mp->flag)) 385 continue; 386 387 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) { 388 redirty = 1; 389 /* 390 * Make sure this page isn't blocked indefinitely. 391 * If the journal isn't undergoing I/O, push it 392 */ 393 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT)) 394 jfs_flush_journal(mp->log, 0); 395 continue; 396 } 397 398 clear_bit(META_dirty, &mp->flag); 399 set_bit(META_io, &mp->flag); 400 block_offset = offset >> inode->i_blkbits; 401 lblock = page_start + block_offset; 402 if (bio) { 403 if (xlen && lblock == next_block) { 404 /* Contiguous, in memory & on disk */ 405 len = min(xlen, blocks_per_mp); 406 xlen -= len; 407 bio_bytes += len << inode->i_blkbits; 408 continue; 409 } 410 /* Not contiguous */ 411 if (bio_add_page(bio, page, bio_bytes, bio_offset) < 412 bio_bytes) 413 goto add_failed; 414 /* 415 * Increment counter before submitting i/o to keep 416 * count from hitting zero before we're through 417 */ 418 inc_io(page); 419 if (!bio->bi_size) 420 goto dump_bio; 421 submit_bio(WRITE, bio); 422 nr_underway++; 423 bio = NULL; 424 } else 425 inc_io(page); 426 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits; 427 pblock = metapage_get_blocks(inode, lblock, &xlen); 428 if (!pblock) { 429 printk(KERN_ERR "JFS: metapage_get_blocks failed\n"); 430 /* 431 * We already called inc_io(), but can't cancel it 432 * with dec_io() until we're done with the page 433 */ 434 bad_blocks++; 435 continue; 436 } 437 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage); 438 439 bio = bio_alloc(GFP_NOFS, 1); 440 bio->bi_bdev = inode->i_sb->s_bdev; 441 bio->bi_sector = pblock << (inode->i_blkbits - 9); 442 bio->bi_end_io = metapage_write_end_io; 443 bio->bi_private = page; 444 445 /* Don't call bio_add_page yet, we may add to this vec */ 446 bio_offset = offset; 447 bio_bytes = len << inode->i_blkbits; 448 449 xlen -= len; 450 next_block = lblock + len; 451 } 452 if (bio) { 453 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes) 454 goto add_failed; 455 if (!bio->bi_size) 456 goto dump_bio; 457 458 submit_bio(WRITE, bio); 459 nr_underway++; 460 } 461 if (redirty) 462 redirty_page_for_writepage(wbc, page); 463 464 unlock_page(page); 465 466 if (bad_blocks) 467 goto err_out; 468 469 if (nr_underway == 0) 470 end_page_writeback(page); 471 472 return 0; 473add_failed: 474 /* We should never reach here, since we're only adding one vec */ 475 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 476 goto skip; 477dump_bio: 478 print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16, 479 4, bio, sizeof(*bio), 0); 480skip: 481 bio_put(bio); 482 unlock_page(page); 483 dec_io(page, last_write_complete); 484err_out: 485 while (bad_blocks--) 486 dec_io(page, last_write_complete); 487 return -EIO; 488} 489 490static int metapage_readpage(struct file *fp, struct page *page) 491{ 492 struct inode *inode = page->mapping->host; 493 struct bio *bio = NULL; 494 int block_offset; 495 int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits; 496 sector_t page_start; /* address of page in fs blocks */ 497 sector_t pblock; 498 int xlen; 499 unsigned int len; 500 int offset; 501 502 BUG_ON(!PageLocked(page)); 503 page_start = (sector_t)page->index << 504 (PAGE_CACHE_SHIFT - inode->i_blkbits); 505 506 block_offset = 0; 507 while (block_offset < blocks_per_page) { 508 xlen = blocks_per_page - block_offset; 509 pblock = metapage_get_blocks(inode, page_start + block_offset, 510 &xlen); 511 if (pblock) { 512 if (!PagePrivate(page)) 513 insert_metapage(page, NULL); 514 inc_io(page); 515 if (bio) 516 submit_bio(READ, bio); 517 518 bio = bio_alloc(GFP_NOFS, 1); 519 bio->bi_bdev = inode->i_sb->s_bdev; 520 bio->bi_sector = pblock << (inode->i_blkbits - 9); 521 bio->bi_end_io = metapage_read_end_io; 522 bio->bi_private = page; 523 len = xlen << inode->i_blkbits; 524 offset = block_offset << inode->i_blkbits; 525 if (bio_add_page(bio, page, len, offset) < len) 526 goto add_failed; 527 block_offset += xlen; 528 } else 529 block_offset++; 530 } 531 if (bio) 532 submit_bio(READ, bio); 533 else 534 unlock_page(page); 535 536 return 0; 537 538add_failed: 539 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 540 bio_put(bio); 541 dec_io(page, last_read_complete); 542 return -EIO; 543} 544 545static int metapage_releasepage(struct page *page, gfp_t gfp_mask) 546{ 547 struct metapage *mp; 548 int ret = 1; 549 int offset; 550 551 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 552 mp = page_to_mp(page, offset); 553 554 if (!mp) 555 continue; 556 557 jfs_info("metapage_releasepage: mp = 0x%p", mp); 558 if (mp->count || mp->nohomeok || 559 test_bit(META_dirty, &mp->flag)) { 560 jfs_info("count = %ld, nohomeok = %d", mp->count, 561 mp->nohomeok); 562 ret = 0; 563 continue; 564 } 565 if (mp->lsn) 566 remove_from_logsync(mp); 567 remove_metapage(page, mp); 568 INCREMENT(mpStat.pagefree); 569 free_metapage(mp); 570 } 571 return ret; 572} 573 574static void metapage_invalidatepage(struct page *page, unsigned long offset) 575{ 576 BUG_ON(offset); 577 578 BUG_ON(PageWriteback(page)); 579 580 metapage_releasepage(page, 0); 581} 582 583const struct address_space_operations jfs_metapage_aops = { 584 .readpage = metapage_readpage, 585 .writepage = metapage_writepage, 586 .sync_page = block_sync_page, 587 .releasepage = metapage_releasepage, 588 .invalidatepage = metapage_invalidatepage, 589 .set_page_dirty = __set_page_dirty_nobuffers, 590}; 591 592struct metapage *__get_metapage(struct inode *inode, unsigned long lblock, 593 unsigned int size, int absolute, 594 unsigned long new) 595{ 596 int l2BlocksPerPage; 597 int l2bsize; 598 struct address_space *mapping; 599 struct metapage *mp = NULL; 600 struct page *page; 601 unsigned long page_index; 602 unsigned long page_offset; 603 604 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d", 605 inode->i_ino, lblock, absolute); 606 607 l2bsize = inode->i_blkbits; 608 l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize; 609 page_index = lblock >> l2BlocksPerPage; 610 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize; 611 if ((page_offset + size) > PAGE_CACHE_SIZE) { 612 jfs_err("MetaData crosses page boundary!!"); 613 jfs_err("lblock = %lx, size = %d", lblock, size); 614 dump_stack(); 615 return NULL; 616 } 617 if (absolute) 618 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping; 619 else { 620 /* 621 * If an nfs client tries to read an inode that is larger 622 * than any existing inodes, we may try to read past the 623 * end of the inode map 624 */ 625 if ((lblock << inode->i_blkbits) >= inode->i_size) 626 return NULL; 627 mapping = inode->i_mapping; 628 } 629 630 if (new && (PSIZE == PAGE_CACHE_SIZE)) { 631 page = grab_cache_page(mapping, page_index); 632 if (!page) { 633 jfs_err("grab_cache_page failed!"); 634 return NULL; 635 } 636 SetPageUptodate(page); 637 } else { 638 page = read_mapping_page(mapping, page_index, NULL); 639 if (IS_ERR(page) || !PageUptodate(page)) { 640 jfs_err("read_mapping_page failed!"); 641 return NULL; 642 } 643 lock_page(page); 644 } 645 646 mp = page_to_mp(page, page_offset); 647 if (mp) { 648 if (mp->logical_size != size) { 649 jfs_error(inode->i_sb, 650 "__get_metapage: mp->logical_size != size"); 651 jfs_err("logical_size = %d, size = %d", 652 mp->logical_size, size); 653 dump_stack(); 654 goto unlock; 655 } 656 mp->count++; 657 lock_metapage(mp); 658 if (test_bit(META_discard, &mp->flag)) { 659 if (!new) { 660 jfs_error(inode->i_sb, 661 "__get_metapage: using a " 662 "discarded metapage"); 663 discard_metapage(mp); 664 goto unlock; 665 } 666 clear_bit(META_discard, &mp->flag); 667 } 668 } else { 669 INCREMENT(mpStat.pagealloc); 670 mp = alloc_metapage(GFP_NOFS); 671 mp->page = page; 672 mp->flag = 0; 673 mp->xflag = COMMIT_PAGE; 674 mp->count = 1; 675 mp->nohomeok = 0; 676 mp->logical_size = size; 677 mp->data = page_address(page) + page_offset; 678 mp->index = lblock; 679 if (unlikely(insert_metapage(page, mp))) { 680 free_metapage(mp); 681 goto unlock; 682 } 683 lock_metapage(mp); 684 } 685 686 if (new) { 687 jfs_info("zeroing mp = 0x%p", mp); 688 memset(mp->data, 0, PSIZE); 689 } 690 691 unlock_page(page); 692 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data); 693 return mp; 694 695unlock: 696 unlock_page(page); 697 return NULL; 698} 699 700void grab_metapage(struct metapage * mp) 701{ 702 jfs_info("grab_metapage: mp = 0x%p", mp); 703 page_cache_get(mp->page); 704 lock_page(mp->page); 705 mp->count++; 706 lock_metapage(mp); 707 unlock_page(mp->page); 708} 709 710void force_metapage(struct metapage *mp) 711{ 712 struct page *page = mp->page; 713 jfs_info("force_metapage: mp = 0x%p", mp); 714 set_bit(META_forcewrite, &mp->flag); 715 clear_bit(META_sync, &mp->flag); 716 page_cache_get(page); 717 lock_page(page); 718 set_page_dirty(page); 719 write_one_page(page, 1); 720 clear_bit(META_forcewrite, &mp->flag); 721 page_cache_release(page); 722} 723 724void hold_metapage(struct metapage *mp) 725{ 726 lock_page(mp->page); 727} 728 729void put_metapage(struct metapage *mp) 730{ 731 if (mp->count || mp->nohomeok) { 732 /* Someone else will release this */ 733 unlock_page(mp->page); 734 return; 735 } 736 page_cache_get(mp->page); 737 mp->count++; 738 lock_metapage(mp); 739 unlock_page(mp->page); 740 release_metapage(mp); 741} 742 743void release_metapage(struct metapage * mp) 744{ 745 struct page *page = mp->page; 746 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag); 747 748 BUG_ON(!page); 749 750 lock_page(page); 751 unlock_metapage(mp); 752 753 assert(mp->count); 754 if (--mp->count || mp->nohomeok) { 755 unlock_page(page); 756 page_cache_release(page); 757 return; 758 } 759 760 if (test_bit(META_dirty, &mp->flag)) { 761 set_page_dirty(page); 762 if (test_bit(META_sync, &mp->flag)) { 763 clear_bit(META_sync, &mp->flag); 764 write_one_page(page, 1); 765 lock_page(page); /* write_one_page unlocks the page */ 766 } 767 } else if (mp->lsn) /* discard_metapage doesn't remove it */ 768 remove_from_logsync(mp); 769 770 /* Try to keep metapages from using up too much memory */ 771 drop_metapage(page, mp); 772 773 unlock_page(page); 774 page_cache_release(page); 775} 776 777void __invalidate_metapages(struct inode *ip, s64 addr, int len) 778{ 779 sector_t lblock; 780 int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits; 781 int BlocksPerPage = 1 << l2BlocksPerPage; 782 /* All callers are interested in block device's mapping */ 783 struct address_space *mapping = 784 JFS_SBI(ip->i_sb)->direct_inode->i_mapping; 785 struct metapage *mp; 786 struct page *page; 787 unsigned int offset; 788 789 /* 790 * Mark metapages to discard. They will eventually be 791 * released, but should not be written. 792 */ 793 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len; 794 lblock += BlocksPerPage) { 795 page = find_lock_page(mapping, lblock >> l2BlocksPerPage); 796 if (!page) 797 continue; 798 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) { 799 mp = page_to_mp(page, offset); 800 if (!mp) 801 continue; 802 if (mp->index < addr) 803 continue; 804 if (mp->index >= addr + len) 805 break; 806 807 clear_bit(META_dirty, &mp->flag); 808 set_bit(META_discard, &mp->flag); 809 if (mp->lsn) 810 remove_from_logsync(mp); 811 } 812 unlock_page(page); 813 page_cache_release(page); 814 } 815} 816 817#ifdef CONFIG_JFS_STATISTICS 818static int jfs_mpstat_proc_show(struct seq_file *m, void *v) 819{ 820 seq_printf(m, 821 "JFS Metapage statistics\n" 822 "=======================\n" 823 "page allocations = %d\n" 824 "page frees = %d\n" 825 "lock waits = %d\n", 826 mpStat.pagealloc, 827 mpStat.pagefree, 828 mpStat.lockwait); 829 return 0; 830} 831 832static int jfs_mpstat_proc_open(struct inode *inode, struct file *file) 833{ 834 return single_open(file, jfs_mpstat_proc_show, NULL); 835} 836 837const struct file_operations jfs_mpstat_proc_fops = { 838 .owner = THIS_MODULE, 839 .open = jfs_mpstat_proc_open, 840 .read = seq_read, 841 .llseek = seq_lseek, 842 .release = single_release, 843}; 844#endif 845