1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) International Business Machines Corp., 2000-2005 4 * Portions Copyright (C) Christoph Hellwig, 2001-2002 5 */ 6 7 #include <linux/fs.h> 8 #include <linux/mm.h> 9 #include <linux/module.h> 10 #include <linux/bio.h> 11 #include <linux/slab.h> 12 #include <linux/init.h> 13 #include <linux/buffer_head.h> 14 #include <linux/mempool.h> 15 #include <linux/seq_file.h> 16 #include "jfs_incore.h" 17 #include "jfs_superblock.h" 18 #include "jfs_filsys.h" 19 #include "jfs_metapage.h" 20 #include "jfs_txnmgr.h" 21 #include "jfs_debug.h" 22 23 #ifdef CONFIG_JFS_STATISTICS 24 static struct { 25 uint pagealloc; /* # of page allocations */ 26 uint pagefree; /* # of page frees */ 27 uint lockwait; /* # of sleeping lock_metapage() calls */ 28 } mpStat; 29 #endif 30 31 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag) 32 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag) 33 34 static inline void unlock_metapage(struct metapage *mp) 35 { 36 clear_bit_unlock(META_locked, &mp->flag); 37 wake_up(&mp->wait); 38 } 39 40 static inline void __lock_metapage(struct metapage *mp) 41 { 42 DECLARE_WAITQUEUE(wait, current); 43 INCREMENT(mpStat.lockwait); 44 add_wait_queue_exclusive(&mp->wait, &wait); 45 do { 46 set_current_state(TASK_UNINTERRUPTIBLE); 47 if (metapage_locked(mp)) { 48 unlock_page(mp->page); 49 io_schedule(); 50 lock_page(mp->page); 51 } 52 } while (trylock_metapage(mp)); 53 __set_current_state(TASK_RUNNING); 54 remove_wait_queue(&mp->wait, &wait); 55 } 56 57 /* 58 * Must have mp->page locked 59 */ 60 static inline void lock_metapage(struct metapage *mp) 61 { 62 if (trylock_metapage(mp)) 63 __lock_metapage(mp); 64 } 65 66 #define METAPOOL_MIN_PAGES 32 67 static struct kmem_cache *metapage_cache; 68 static mempool_t *metapage_mempool; 69 70 #define MPS_PER_PAGE (PAGE_SIZE >> L2PSIZE) 71 72 #if MPS_PER_PAGE > 1 73 74 struct meta_anchor { 75 int mp_count; 76 atomic_t io_count; 77 struct metapage *mp[MPS_PER_PAGE]; 78 }; 79 #define mp_anchor(page) ((struct meta_anchor *)page_private(page)) 80 81 static inline struct metapage *page_to_mp(struct page *page, int offset) 82 { 83 if (!PagePrivate(page)) 84 return NULL; 85 return mp_anchor(page)->mp[offset >> L2PSIZE]; 86 } 87 88 static inline int insert_metapage(struct page *page, struct metapage *mp) 89 { 90 struct meta_anchor *a; 91 int index; 92 int l2mp_blocks; /* log2 blocks per metapage */ 93 94 if (PagePrivate(page)) 95 a = mp_anchor(page); 96 else { 97 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS); 98 if (!a) 99 return -ENOMEM; 100 set_page_private(page, (unsigned long)a); 101 SetPagePrivate(page); 102 kmap(page); 103 } 104 105 if (mp) { 106 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits; 107 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1); 108 a->mp_count++; 109 a->mp[index] = mp; 110 } 111 112 return 0; 113 } 114 115 static inline void remove_metapage(struct page *page, struct metapage *mp) 116 { 117 struct meta_anchor *a = mp_anchor(page); 118 int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits; 119 int index; 120 121 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1); 122 123 BUG_ON(a->mp[index] != mp); 124 125 a->mp[index] = NULL; 126 if (--a->mp_count == 0) { 127 kfree(a); 128 set_page_private(page, 0); 129 ClearPagePrivate(page); 130 kunmap(page); 131 } 132 } 133 134 static inline void inc_io(struct page *page) 135 { 136 atomic_inc(&mp_anchor(page)->io_count); 137 } 138 139 static inline void dec_io(struct page *page, void (*handler) (struct page *)) 140 { 141 if (atomic_dec_and_test(&mp_anchor(page)->io_count)) 142 handler(page); 143 } 144 145 #else 146 static inline struct metapage *page_to_mp(struct page *page, int offset) 147 { 148 return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL; 149 } 150 151 static inline int insert_metapage(struct page *page, struct metapage *mp) 152 { 153 if (mp) { 154 set_page_private(page, (unsigned long)mp); 155 SetPagePrivate(page); 156 kmap(page); 157 } 158 return 0; 159 } 160 161 static inline void remove_metapage(struct page *page, struct metapage *mp) 162 { 163 set_page_private(page, 0); 164 ClearPagePrivate(page); 165 kunmap(page); 166 } 167 168 #define inc_io(page) do {} while(0) 169 #define dec_io(page, handler) handler(page) 170 171 #endif 172 173 static inline struct metapage *alloc_metapage(gfp_t gfp_mask) 174 { 175 struct metapage *mp = mempool_alloc(metapage_mempool, gfp_mask); 176 177 if (mp) { 178 mp->lid = 0; 179 mp->lsn = 0; 180 mp->data = NULL; 181 mp->clsn = 0; 182 mp->log = NULL; 183 init_waitqueue_head(&mp->wait); 184 } 185 return mp; 186 } 187 188 static inline void free_metapage(struct metapage *mp) 189 { 190 mempool_free(mp, metapage_mempool); 191 } 192 193 int __init metapage_init(void) 194 { 195 /* 196 * Allocate the metapage structures 197 */ 198 metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage), 199 0, 0, NULL); 200 if (metapage_cache == NULL) 201 return -ENOMEM; 202 203 metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES, 204 metapage_cache); 205 206 if (metapage_mempool == NULL) { 207 kmem_cache_destroy(metapage_cache); 208 return -ENOMEM; 209 } 210 211 return 0; 212 } 213 214 void metapage_exit(void) 215 { 216 mempool_destroy(metapage_mempool); 217 kmem_cache_destroy(metapage_cache); 218 } 219 220 static inline void drop_metapage(struct page *page, struct metapage *mp) 221 { 222 if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) || 223 test_bit(META_io, &mp->flag)) 224 return; 225 remove_metapage(page, mp); 226 INCREMENT(mpStat.pagefree); 227 free_metapage(mp); 228 } 229 230 /* 231 * Metapage address space operations 232 */ 233 234 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock, 235 int *len) 236 { 237 int rc = 0; 238 int xflag; 239 s64 xaddr; 240 sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >> 241 inode->i_blkbits; 242 243 if (lblock >= file_blocks) 244 return 0; 245 if (lblock + *len > file_blocks) 246 *len = file_blocks - lblock; 247 248 if (inode->i_ino) { 249 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0); 250 if ((rc == 0) && *len) 251 lblock = (sector_t)xaddr; 252 else 253 lblock = 0; 254 } /* else no mapping */ 255 256 return lblock; 257 } 258 259 static void last_read_complete(struct page *page) 260 { 261 if (!PageError(page)) 262 SetPageUptodate(page); 263 unlock_page(page); 264 } 265 266 static void metapage_read_end_io(struct bio *bio) 267 { 268 struct page *page = bio->bi_private; 269 270 if (bio->bi_status) { 271 printk(KERN_ERR "metapage_read_end_io: I/O error\n"); 272 SetPageError(page); 273 } 274 275 dec_io(page, last_read_complete); 276 bio_put(bio); 277 } 278 279 static void remove_from_logsync(struct metapage *mp) 280 { 281 struct jfs_log *log = mp->log; 282 unsigned long flags; 283 /* 284 * This can race. Recheck that log hasn't been set to null, and after 285 * acquiring logsync lock, recheck lsn 286 */ 287 if (!log) 288 return; 289 290 LOGSYNC_LOCK(log, flags); 291 if (mp->lsn) { 292 mp->log = NULL; 293 mp->lsn = 0; 294 mp->clsn = 0; 295 log->count--; 296 list_del(&mp->synclist); 297 } 298 LOGSYNC_UNLOCK(log, flags); 299 } 300 301 static void last_write_complete(struct page *page) 302 { 303 struct metapage *mp; 304 unsigned int offset; 305 306 for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) { 307 mp = page_to_mp(page, offset); 308 if (mp && test_bit(META_io, &mp->flag)) { 309 if (mp->lsn) 310 remove_from_logsync(mp); 311 clear_bit(META_io, &mp->flag); 312 } 313 /* 314 * I'd like to call drop_metapage here, but I don't think it's 315 * safe unless I have the page locked 316 */ 317 } 318 end_page_writeback(page); 319 } 320 321 static void metapage_write_end_io(struct bio *bio) 322 { 323 struct page *page = bio->bi_private; 324 325 BUG_ON(!PagePrivate(page)); 326 327 if (bio->bi_status) { 328 printk(KERN_ERR "metapage_write_end_io: I/O error\n"); 329 SetPageError(page); 330 } 331 dec_io(page, last_write_complete); 332 bio_put(bio); 333 } 334 335 static int metapage_writepage(struct page *page, struct writeback_control *wbc) 336 { 337 struct bio *bio = NULL; 338 int block_offset; /* block offset of mp within page */ 339 struct inode *inode = page->mapping->host; 340 int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage; 341 int len; 342 int xlen; 343 struct metapage *mp; 344 int redirty = 0; 345 sector_t lblock; 346 int nr_underway = 0; 347 sector_t pblock; 348 sector_t next_block = 0; 349 sector_t page_start; 350 unsigned long bio_bytes = 0; 351 unsigned long bio_offset = 0; 352 int offset; 353 int bad_blocks = 0; 354 355 page_start = (sector_t)page->index << 356 (PAGE_SHIFT - inode->i_blkbits); 357 BUG_ON(!PageLocked(page)); 358 BUG_ON(PageWriteback(page)); 359 set_page_writeback(page); 360 361 for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) { 362 mp = page_to_mp(page, offset); 363 364 if (!mp || !test_bit(META_dirty, &mp->flag)) 365 continue; 366 367 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) { 368 redirty = 1; 369 /* 370 * Make sure this page isn't blocked indefinitely. 371 * If the journal isn't undergoing I/O, push it 372 */ 373 if (mp->log && !(mp->log->cflag & logGC_PAGEOUT)) 374 jfs_flush_journal(mp->log, 0); 375 continue; 376 } 377 378 clear_bit(META_dirty, &mp->flag); 379 set_bit(META_io, &mp->flag); 380 block_offset = offset >> inode->i_blkbits; 381 lblock = page_start + block_offset; 382 if (bio) { 383 if (xlen && lblock == next_block) { 384 /* Contiguous, in memory & on disk */ 385 len = min(xlen, blocks_per_mp); 386 xlen -= len; 387 bio_bytes += len << inode->i_blkbits; 388 continue; 389 } 390 /* Not contiguous */ 391 if (bio_add_page(bio, page, bio_bytes, bio_offset) < 392 bio_bytes) 393 goto add_failed; 394 /* 395 * Increment counter before submitting i/o to keep 396 * count from hitting zero before we're through 397 */ 398 inc_io(page); 399 if (!bio->bi_iter.bi_size) 400 goto dump_bio; 401 submit_bio(bio); 402 nr_underway++; 403 bio = NULL; 404 } else 405 inc_io(page); 406 xlen = (PAGE_SIZE - offset) >> inode->i_blkbits; 407 pblock = metapage_get_blocks(inode, lblock, &xlen); 408 if (!pblock) { 409 printk(KERN_ERR "JFS: metapage_get_blocks failed\n"); 410 /* 411 * We already called inc_io(), but can't cancel it 412 * with dec_io() until we're done with the page 413 */ 414 bad_blocks++; 415 continue; 416 } 417 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage); 418 419 bio = bio_alloc(GFP_NOFS, 1); 420 bio_set_dev(bio, inode->i_sb->s_bdev); 421 bio->bi_iter.bi_sector = pblock << (inode->i_blkbits - 9); 422 bio->bi_end_io = metapage_write_end_io; 423 bio->bi_private = page; 424 bio_set_op_attrs(bio, REQ_OP_WRITE, 0); 425 426 /* Don't call bio_add_page yet, we may add to this vec */ 427 bio_offset = offset; 428 bio_bytes = len << inode->i_blkbits; 429 430 xlen -= len; 431 next_block = lblock + len; 432 } 433 if (bio) { 434 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes) 435 goto add_failed; 436 if (!bio->bi_iter.bi_size) 437 goto dump_bio; 438 439 submit_bio(bio); 440 nr_underway++; 441 } 442 if (redirty) 443 redirty_page_for_writepage(wbc, page); 444 445 unlock_page(page); 446 447 if (bad_blocks) 448 goto err_out; 449 450 if (nr_underway == 0) 451 end_page_writeback(page); 452 453 return 0; 454 add_failed: 455 /* We should never reach here, since we're only adding one vec */ 456 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 457 goto skip; 458 dump_bio: 459 print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16, 460 4, bio, sizeof(*bio), 0); 461 skip: 462 bio_put(bio); 463 unlock_page(page); 464 dec_io(page, last_write_complete); 465 err_out: 466 while (bad_blocks--) 467 dec_io(page, last_write_complete); 468 return -EIO; 469 } 470 471 static int metapage_readpage(struct file *fp, struct page *page) 472 { 473 struct inode *inode = page->mapping->host; 474 struct bio *bio = NULL; 475 int block_offset; 476 int blocks_per_page = i_blocks_per_page(inode, page); 477 sector_t page_start; /* address of page in fs blocks */ 478 sector_t pblock; 479 int xlen; 480 unsigned int len; 481 int offset; 482 483 BUG_ON(!PageLocked(page)); 484 page_start = (sector_t)page->index << 485 (PAGE_SHIFT - inode->i_blkbits); 486 487 block_offset = 0; 488 while (block_offset < blocks_per_page) { 489 xlen = blocks_per_page - block_offset; 490 pblock = metapage_get_blocks(inode, page_start + block_offset, 491 &xlen); 492 if (pblock) { 493 if (!PagePrivate(page)) 494 insert_metapage(page, NULL); 495 inc_io(page); 496 if (bio) 497 submit_bio(bio); 498 499 bio = bio_alloc(GFP_NOFS, 1); 500 bio_set_dev(bio, inode->i_sb->s_bdev); 501 bio->bi_iter.bi_sector = 502 pblock << (inode->i_blkbits - 9); 503 bio->bi_end_io = metapage_read_end_io; 504 bio->bi_private = page; 505 bio_set_op_attrs(bio, REQ_OP_READ, 0); 506 len = xlen << inode->i_blkbits; 507 offset = block_offset << inode->i_blkbits; 508 if (bio_add_page(bio, page, len, offset) < len) 509 goto add_failed; 510 block_offset += xlen; 511 } else 512 block_offset++; 513 } 514 if (bio) 515 submit_bio(bio); 516 else 517 unlock_page(page); 518 519 return 0; 520 521 add_failed: 522 printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n"); 523 bio_put(bio); 524 dec_io(page, last_read_complete); 525 return -EIO; 526 } 527 528 static int metapage_releasepage(struct page *page, gfp_t gfp_mask) 529 { 530 struct metapage *mp; 531 int ret = 1; 532 int offset; 533 534 for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) { 535 mp = page_to_mp(page, offset); 536 537 if (!mp) 538 continue; 539 540 jfs_info("metapage_releasepage: mp = 0x%p", mp); 541 if (mp->count || mp->nohomeok || 542 test_bit(META_dirty, &mp->flag)) { 543 jfs_info("count = %ld, nohomeok = %d", mp->count, 544 mp->nohomeok); 545 ret = 0; 546 continue; 547 } 548 if (mp->lsn) 549 remove_from_logsync(mp); 550 remove_metapage(page, mp); 551 INCREMENT(mpStat.pagefree); 552 free_metapage(mp); 553 } 554 return ret; 555 } 556 557 static void metapage_invalidatepage(struct page *page, unsigned int offset, 558 unsigned int length) 559 { 560 BUG_ON(offset || length < PAGE_SIZE); 561 562 BUG_ON(PageWriteback(page)); 563 564 metapage_releasepage(page, 0); 565 } 566 567 const struct address_space_operations jfs_metapage_aops = { 568 .readpage = metapage_readpage, 569 .writepage = metapage_writepage, 570 .releasepage = metapage_releasepage, 571 .invalidatepage = metapage_invalidatepage, 572 .set_page_dirty = __set_page_dirty_nobuffers, 573 }; 574 575 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock, 576 unsigned int size, int absolute, 577 unsigned long new) 578 { 579 int l2BlocksPerPage; 580 int l2bsize; 581 struct address_space *mapping; 582 struct metapage *mp = NULL; 583 struct page *page; 584 unsigned long page_index; 585 unsigned long page_offset; 586 587 jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d", 588 inode->i_ino, lblock, absolute); 589 590 l2bsize = inode->i_blkbits; 591 l2BlocksPerPage = PAGE_SHIFT - l2bsize; 592 page_index = lblock >> l2BlocksPerPage; 593 page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize; 594 if ((page_offset + size) > PAGE_SIZE) { 595 jfs_err("MetaData crosses page boundary!!"); 596 jfs_err("lblock = %lx, size = %d", lblock, size); 597 dump_stack(); 598 return NULL; 599 } 600 if (absolute) 601 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping; 602 else { 603 /* 604 * If an nfs client tries to read an inode that is larger 605 * than any existing inodes, we may try to read past the 606 * end of the inode map 607 */ 608 if ((lblock << inode->i_blkbits) >= inode->i_size) 609 return NULL; 610 mapping = inode->i_mapping; 611 } 612 613 if (new && (PSIZE == PAGE_SIZE)) { 614 page = grab_cache_page(mapping, page_index); 615 if (!page) { 616 jfs_err("grab_cache_page failed!"); 617 return NULL; 618 } 619 SetPageUptodate(page); 620 } else { 621 page = read_mapping_page(mapping, page_index, NULL); 622 if (IS_ERR(page) || !PageUptodate(page)) { 623 jfs_err("read_mapping_page failed!"); 624 return NULL; 625 } 626 lock_page(page); 627 } 628 629 mp = page_to_mp(page, page_offset); 630 if (mp) { 631 if (mp->logical_size != size) { 632 jfs_error(inode->i_sb, 633 "get_mp->logical_size != size\n"); 634 jfs_err("logical_size = %d, size = %d", 635 mp->logical_size, size); 636 dump_stack(); 637 goto unlock; 638 } 639 mp->count++; 640 lock_metapage(mp); 641 if (test_bit(META_discard, &mp->flag)) { 642 if (!new) { 643 jfs_error(inode->i_sb, 644 "using a discarded metapage\n"); 645 discard_metapage(mp); 646 goto unlock; 647 } 648 clear_bit(META_discard, &mp->flag); 649 } 650 } else { 651 INCREMENT(mpStat.pagealloc); 652 mp = alloc_metapage(GFP_NOFS); 653 if (!mp) 654 goto unlock; 655 mp->page = page; 656 mp->sb = inode->i_sb; 657 mp->flag = 0; 658 mp->xflag = COMMIT_PAGE; 659 mp->count = 1; 660 mp->nohomeok = 0; 661 mp->logical_size = size; 662 mp->data = page_address(page) + page_offset; 663 mp->index = lblock; 664 if (unlikely(insert_metapage(page, mp))) { 665 free_metapage(mp); 666 goto unlock; 667 } 668 lock_metapage(mp); 669 } 670 671 if (new) { 672 jfs_info("zeroing mp = 0x%p", mp); 673 memset(mp->data, 0, PSIZE); 674 } 675 676 unlock_page(page); 677 jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data); 678 return mp; 679 680 unlock: 681 unlock_page(page); 682 return NULL; 683 } 684 685 void grab_metapage(struct metapage * mp) 686 { 687 jfs_info("grab_metapage: mp = 0x%p", mp); 688 get_page(mp->page); 689 lock_page(mp->page); 690 mp->count++; 691 lock_metapage(mp); 692 unlock_page(mp->page); 693 } 694 695 void force_metapage(struct metapage *mp) 696 { 697 struct page *page = mp->page; 698 jfs_info("force_metapage: mp = 0x%p", mp); 699 set_bit(META_forcewrite, &mp->flag); 700 clear_bit(META_sync, &mp->flag); 701 get_page(page); 702 lock_page(page); 703 set_page_dirty(page); 704 if (write_one_page(page)) 705 jfs_error(mp->sb, "write_one_page() failed\n"); 706 clear_bit(META_forcewrite, &mp->flag); 707 put_page(page); 708 } 709 710 void hold_metapage(struct metapage *mp) 711 { 712 lock_page(mp->page); 713 } 714 715 void put_metapage(struct metapage *mp) 716 { 717 if (mp->count || mp->nohomeok) { 718 /* Someone else will release this */ 719 unlock_page(mp->page); 720 return; 721 } 722 get_page(mp->page); 723 mp->count++; 724 lock_metapage(mp); 725 unlock_page(mp->page); 726 release_metapage(mp); 727 } 728 729 void release_metapage(struct metapage * mp) 730 { 731 struct page *page = mp->page; 732 jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag); 733 734 BUG_ON(!page); 735 736 lock_page(page); 737 unlock_metapage(mp); 738 739 assert(mp->count); 740 if (--mp->count || mp->nohomeok) { 741 unlock_page(page); 742 put_page(page); 743 return; 744 } 745 746 if (test_bit(META_dirty, &mp->flag)) { 747 set_page_dirty(page); 748 if (test_bit(META_sync, &mp->flag)) { 749 clear_bit(META_sync, &mp->flag); 750 if (write_one_page(page)) 751 jfs_error(mp->sb, "write_one_page() failed\n"); 752 lock_page(page); /* write_one_page unlocks the page */ 753 } 754 } else if (mp->lsn) /* discard_metapage doesn't remove it */ 755 remove_from_logsync(mp); 756 757 /* Try to keep metapages from using up too much memory */ 758 drop_metapage(page, mp); 759 760 unlock_page(page); 761 put_page(page); 762 } 763 764 void __invalidate_metapages(struct inode *ip, s64 addr, int len) 765 { 766 sector_t lblock; 767 int l2BlocksPerPage = PAGE_SHIFT - ip->i_blkbits; 768 int BlocksPerPage = 1 << l2BlocksPerPage; 769 /* All callers are interested in block device's mapping */ 770 struct address_space *mapping = 771 JFS_SBI(ip->i_sb)->direct_inode->i_mapping; 772 struct metapage *mp; 773 struct page *page; 774 unsigned int offset; 775 776 /* 777 * Mark metapages to discard. They will eventually be 778 * released, but should not be written. 779 */ 780 for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len; 781 lblock += BlocksPerPage) { 782 page = find_lock_page(mapping, lblock >> l2BlocksPerPage); 783 if (!page) 784 continue; 785 for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) { 786 mp = page_to_mp(page, offset); 787 if (!mp) 788 continue; 789 if (mp->index < addr) 790 continue; 791 if (mp->index >= addr + len) 792 break; 793 794 clear_bit(META_dirty, &mp->flag); 795 set_bit(META_discard, &mp->flag); 796 if (mp->lsn) 797 remove_from_logsync(mp); 798 } 799 unlock_page(page); 800 put_page(page); 801 } 802 } 803 804 #ifdef CONFIG_JFS_STATISTICS 805 int jfs_mpstat_proc_show(struct seq_file *m, void *v) 806 { 807 seq_printf(m, 808 "JFS Metapage statistics\n" 809 "=======================\n" 810 "page allocations = %d\n" 811 "page frees = %d\n" 812 "lock waits = %d\n", 813 mpStat.pagealloc, 814 mpStat.pagefree, 815 mpStat.lockwait); 816 return 0; 817 } 818 #endif 819