fs/jfs/jfs_metapage.c

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