fs/jfs/jfs_metapage.c

   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
  34 static 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
  44 static inline void unlock_metapage(struct metapage *mp)
  45 {
  46         clear_bit(META_locked, &mp->flag);
  47         wake_up(&mp->wait);
  48 }
  49
  50 static 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                         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  */
  70 static 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
  77 static kmem_cache_t *metapage_cache;
  78 static mempool_t *metapage_mempool;
  79
  80 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
  81
  82 #if MPS_PER_PAGE > 1
  83
  84 struct 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)
  90
  91 static 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
  98 static 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 = kmalloc(sizeof(struct meta_anchor), GFP_NOFS);
 108                 if (!a)
 109                         return -ENOMEM;
 110                 memset(a, 0, sizeof(struct meta_anchor));
 111                 page->private = (unsigned long)a;
 112                 SetPagePrivate(page);
 113                 kmap(page);
 114         }
 115
 116         if (mp) {
 117                 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
 118                 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 119                 a->mp_count++;
 120                 a->mp[index] = mp;
 121         }
 122
 123         return 0;
 124 }
 125
 126 static inline void remove_metapage(struct page *page, struct metapage *mp)
 127 {
 128         struct meta_anchor *a = mp_anchor(page);
 129         int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
 130         int index;
 131
 132         index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 133
 134         BUG_ON(a->mp[index] != mp);
 135
 136         a->mp[index] = NULL;
 137         if (--a->mp_count == 0) {
 138                 kfree(a);
 139                 page->private = 0;
 140                 ClearPagePrivate(page);
 141                 kunmap(page);
 142         }
 143 }
 144
 145 static inline void inc_io(struct page *page)
 146 {
 147         atomic_inc(&mp_anchor(page)->io_count);
 148 }
 149
 150 static inline void dec_io(struct page *page, void (*handler) (struct page *))
 151 {
 152         if (atomic_dec_and_test(&mp_anchor(page)->io_count))
 153                 handler(page);
 154 }
 155
 156 #else
 157 static inline struct metapage *page_to_mp(struct page *page, uint offset)
 158 {
 159         return PagePrivate(page) ? (struct metapage *)page->private : NULL;
 160 }
 161
 162 static inline int insert_metapage(struct page *page, struct metapage *mp)
 163 {
 164         if (mp) {
 165                 page->private = (unsigned long)mp;
 166                 SetPagePrivate(page);
 167                 kmap(page);
 168         }
 169         return 0;
 170 }
 171
 172 static inline void remove_metapage(struct page *page, struct metapage *mp)
 173 {
 174         page->private = 0;
 175         ClearPagePrivate(page);
 176         kunmap(page);
 177 }
 178
 179 #define inc_io(page) do {} while(0)
 180 #define dec_io(page, handler) handler(page)
 181
 182 #endif
 183
 184 static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
 185 {
 186         struct metapage *mp = (struct metapage *)foo;
 187
 188         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 189             SLAB_CTOR_CONSTRUCTOR) {
 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 }
 200
 201 static inline struct metapage *alloc_metapage(unsigned int gfp_mask)
 202 {
 203         return mempool_alloc(metapage_mempool, gfp_mask);
 204 }
 205
 206 static inline void free_metapage(struct metapage *mp)
 207 {
 208         mp->flag = 0;
 209         set_bit(META_free, &mp->flag);
 210
 211         mempool_free(mp, metapage_mempool);
 212 }
 213
 214 int __init metapage_init(void)
 215 {
 216         /*
 217          * Allocate the metapage structures
 218          */
 219         metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
 220                                            0, 0, init_once, NULL);
 221         if (metapage_cache == NULL)
 222                 return -ENOMEM;
 223
 224         metapage_mempool = mempool_create(METAPOOL_MIN_PAGES, mempool_alloc_slab,
 225                                           mempool_free_slab, metapage_cache);
 226
 227         if (metapage_mempool == NULL) {
 228                 kmem_cache_destroy(metapage_cache);
 229                 return -ENOMEM;
 230         }
 231
 232         return 0;
 233 }
 234
 235 void metapage_exit(void)
 236 {
 237         mempool_destroy(metapage_mempool);
 238         kmem_cache_destroy(metapage_cache);
 239 }
 240
 241 static inline void drop_metapage(struct page *page, struct metapage *mp)
 242 {
 243         if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
 244             test_bit(META_io, &mp->flag))
 245                 return;
 246         remove_metapage(page, mp);
 247         INCREMENT(mpStat.pagefree);
 248         free_metapage(mp);
 249 }
 250
 251 /*
 252  * Metapage address space operations
 253  */
 254
 255 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
 256                                     unsigned int *len)
 257 {
 258         int rc = 0;
 259         int xflag;
 260         s64 xaddr;
 261         sector_t file_blocks = (inode->i_size + inode->i_blksize - 1) >>
 262                                inode->i_blkbits;
 263
 264         if (lblock >= file_blocks)
 265                 return 0;
 266         if (lblock + *len > file_blocks)
 267                 *len = file_blocks - lblock;
 268
 269         if (inode->i_ino) {
 270                 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
 271                 if ((rc == 0) && *len)
 272                         lblock = (sector_t)xaddr;
 273                 else
 274                         lblock = 0;
 275         } /* else no mapping */
 276
 277         return lblock;
 278 }
 279
 280 static void last_read_complete(struct page *page)
 281 {
 282         if (!PageError(page))
 283                 SetPageUptodate(page);
 284         unlock_page(page);
 285 }
 286
 287 static int metapage_read_end_io(struct bio *bio, unsigned int bytes_done,
 288                                 int err)
 289 {
 290         struct page *page = bio->bi_private;
 291
 292         if (bio->bi_size)
 293                 return 1;
 294
 295         if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 296                 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
 297                 SetPageError(page);
 298         }
 299
 300         dec_io(page, last_read_complete);
 301         bio_put(bio);
 302
 303         return 0;
 304 }
 305
 306 static void remove_from_logsync(struct metapage *mp)
 307 {
 308         struct jfs_log *log = mp->log;
 309         unsigned long flags;
 310 /*
 311  * This can race.  Recheck that log hasn't been set to null, and after
 312  * acquiring logsync lock, recheck lsn
 313  */
 314         if (!log)
 315                 return;
 316
 317         LOGSYNC_LOCK(log, flags);
 318         if (mp->lsn) {
 319                 mp->log = NULL;
 320                 mp->lsn = 0;
 321                 mp->clsn = 0;
 322                 log->count--;
 323                 list_del(&mp->synclist);
 324         }
 325         LOGSYNC_UNLOCK(log, flags);
 326 }
 327
 328 static void last_write_complete(struct page *page)
 329 {
 330         struct metapage *mp;
 331         unsigned int offset;
 332
 333         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 334                 mp = page_to_mp(page, offset);
 335                 if (mp && test_bit(META_io, &mp->flag)) {
 336                         if (mp->lsn)
 337                                 remove_from_logsync(mp);
 338                         clear_bit(META_io, &mp->flag);
 339                 }
 340                 /*
 341                  * I'd like to call drop_metapage here, but I don't think it's
 342                  * safe unless I have the page locked
 343                  */
 344         }
 345         end_page_writeback(page);
 346 }
 347
 348 static int metapage_write_end_io(struct bio *bio, unsigned int bytes_done,
 349                                  int err)
 350 {
 351         struct page *page = bio->bi_private;
 352
 353         BUG_ON(!PagePrivate(page));
 354
 355         if (bio->bi_size)
 356                 return 1;
 357
 358         if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 359                 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
 360                 SetPageError(page);
 361         }
 362         dec_io(page, last_write_complete);
 363         bio_put(bio);
 364         return 0;
 365 }
 366
 367 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 368 {
 369         struct bio *bio = NULL;
 370         unsigned int block_offset;      /* block offset of mp within page */
 371         struct inode *inode = page->mapping->host;
 372         unsigned int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
 373         unsigned int len;
 374         unsigned int xlen;
 375         struct metapage *mp;
 376         int redirty = 0;
 377         sector_t lblock;
 378         sector_t pblock;
 379         sector_t next_block = 0;
 380         sector_t page_start;
 381         unsigned long bio_bytes = 0;
 382         unsigned long bio_offset = 0;
 383         unsigned int offset;
 384
 385         page_start = (sector_t)page->index <<
 386                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
 387         BUG_ON(!PageLocked(page));
 388         BUG_ON(PageWriteback(page));
 389
 390         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 391                 mp = page_to_mp(page, offset);
 392
 393                 if (!mp || !test_bit(META_dirty, &mp->flag))
 394                         continue;
 395
 396                 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
 397                         redirty = 1;
 398                         continue;
 399                 }
 400
 401                 clear_bit(META_dirty, &mp->flag);
 402                 block_offset = offset >> inode->i_blkbits;
 403                 lblock = page_start + block_offset;
 404                 if (bio) {
 405                         if (xlen && lblock == next_block) {
 406                                 /* Contiguous, in memory & on disk */
 407                                 len = min(xlen, blocks_per_mp);
 408                                 xlen -= len;
 409                                 bio_bytes += len << inode->i_blkbits;
 410                                 set_bit(META_io, &mp->flag);
 411                                 continue;
 412                         }
 413                         /* Not contiguous */
 414                         if (bio_add_page(bio, page, bio_bytes, bio_offset) <
 415                             bio_bytes)
 416                                 goto add_failed;
 417                         /*
 418                          * Increment counter before submitting i/o to keep
 419                          * count from hitting zero before we're through
 420                          */
 421                         inc_io(page);
 422                         if (!bio->bi_size)
 423                                 goto dump_bio;
 424                         submit_bio(WRITE, bio);
 425                         bio = NULL;
 426                 } else {
 427                         set_page_writeback(page);
 428                         inc_io(page);
 429                 }
 430                 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
 431                 pblock = metapage_get_blocks(inode, lblock, &xlen);
 432                 if (!pblock) {
 433                         /* Need better error handling */
 434                         printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
 435                         dec_io(page, last_write_complete);
 436                         continue;
 437                 }
 438                 set_bit(META_io, &mp->flag);
 439                 len = min(xlen, (uint) JFS_SBI(inode->i_sb)->nbperpage);
 440
 441                 bio = bio_alloc(GFP_NOFS, 1);
 442                 bio->bi_bdev = inode->i_sb->s_bdev;
 443                 bio->bi_sector = pblock << (inode->i_blkbits - 9);
 444                 bio->bi_end_io = metapage_write_end_io;
 445                 bio->bi_private = page;
 446
 447                 /* Don't call bio_add_page yet, we may add to this vec */
 448                 bio_offset = offset;
 449                 bio_bytes = len << inode->i_blkbits;
 450
 451                 xlen -= len;
 452                 next_block = lblock + len;
 453         }
 454         if (bio) {
 455                 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
 456                                 goto add_failed;
 457                 if (!bio->bi_size)
 458                         goto dump_bio;
 459
 460                 submit_bio(WRITE, bio);
 461         }
 462         if (redirty)
 463                 redirty_page_for_writepage(wbc, page);
 464
 465         unlock_page(page);
 466
 467         return 0;
 468 add_failed:
 469         /* We should never reach here, since we're only adding one vec */
 470         printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
 471         goto skip;
 472 dump_bio:
 473         dump_mem("bio", bio, sizeof(*bio));
 474 skip:
 475         bio_put(bio);
 476         unlock_page(page);
 477         dec_io(page, last_write_complete);
 478
 479         return -EIO;
 480 }
 481
 482 static int metapage_readpage(struct file *fp, struct page *page)
 483 {
 484         struct inode *inode = page->mapping->host;
 485         struct bio *bio = NULL;
 486         unsigned int block_offset;
 487         unsigned int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
 488         sector_t page_start;    /* address of page in fs blocks */
 489         sector_t pblock;
 490         unsigned int xlen;
 491         unsigned int len;
 492         unsigned int offset;
 493
 494         BUG_ON(!PageLocked(page));
 495         page_start = (sector_t)page->index <<
 496                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
 497
 498         block_offset = 0;
 499         while (block_offset < blocks_per_page) {
 500                 xlen = blocks_per_page - block_offset;
 501                 pblock = metapage_get_blocks(inode, page_start + block_offset,
 502                                              &xlen);
 503                 if (pblock) {
 504                         if (!PagePrivate(page))
 505                                 insert_metapage(page, NULL);
 506                         inc_io(page);
 507                         if (bio)
 508                                 submit_bio(READ, bio);
 509
 510                         bio = bio_alloc(GFP_NOFS, 1);
 511                         bio->bi_bdev = inode->i_sb->s_bdev;
 512                         bio->bi_sector = pblock << (inode->i_blkbits - 9);
 513                         bio->bi_end_io = metapage_read_end_io;
 514                         bio->bi_private = page;
 515                         len = xlen << inode->i_blkbits;
 516                         offset = block_offset << inode->i_blkbits;
 517                         if (bio_add_page(bio, page, len, offset) < len)
 518                                 goto add_failed;
 519                         block_offset += xlen;
 520                 } else
 521                         block_offset++;
 522         }
 523         if (bio)
 524                 submit_bio(READ, bio);
 525         else
 526                 unlock_page(page);
 527
 528         return 0;
 529
 530 add_failed:
 531         printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
 532         bio_put(bio);
 533         dec_io(page, last_read_complete);
 534         return -EIO;
 535 }
 536
 537 static int metapage_releasepage(struct page *page, int gfp_mask)
 538 {
 539         struct metapage *mp;
 540         int busy = 0;
 541         unsigned int offset;
 542
 543         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 544                 mp = page_to_mp(page, offset);
 545
 546                 if (!mp)
 547                         continue;
 548
 549                 jfs_info("metapage_releasepage: mp = 0x%p", mp);
 550                 if (mp->count || mp->nohomeok) {
 551                         jfs_info("count = %ld, nohomeok = %d", mp->count,
 552                                  mp->nohomeok);
 553                         busy = 1;
 554                         continue;
 555                 }
 556                 wait_on_page_writeback(page);
 557                 //WARN_ON(test_bit(META_dirty, &mp->flag));
 558                 if (test_bit(META_dirty, &mp->flag)) {
 559                         dump_mem("dirty mp in metapage_releasepage", mp,
 560                                  sizeof(struct metapage));
 561                         dump_mem("page", page, sizeof(struct page));
 562                         dump_stack();
 563                 }
 564                 if (mp->lsn)
 565                         remove_from_logsync(mp);
 566                 remove_metapage(page, mp);
 567                 INCREMENT(mpStat.pagefree);
 568                 free_metapage(mp);
 569         }
 570         if (busy)
 571                 return -1;
 572
 573         return 0;
 574 }
 575
 576 static int metapage_invalidatepage(struct page *page, unsigned long offset)
 577 {
 578         BUG_ON(offset);
 579
 580         if (PageWriteback(page))
 581                 return 0;
 582
 583         return metapage_releasepage(page, 0);
 584 }
 585
 586 struct address_space_operations jfs_metapage_aops = {
 587         .readpage       = metapage_readpage,
 588         .writepage      = metapage_writepage,
 589         .sync_page      = block_sync_page,
 590         .releasepage    = metapage_releasepage,
 591         .invalidatepage = metapage_invalidatepage,
 592         .set_page_dirty = __set_page_dirty_nobuffers,
 593 };
 594
 595 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 596                                 unsigned int size, int absolute,
 597                                 unsigned long new)
 598 {
 599         int l2BlocksPerPage;
 600         int l2bsize;
 601         struct address_space *mapping;
 602         struct metapage *mp = NULL;
 603         struct page *page;
 604         unsigned long page_index;
 605         unsigned long page_offset;
 606
 607         jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
 608                  inode->i_ino, lblock, absolute);
 609
 610         l2bsize = inode->i_blkbits;
 611         l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
 612         page_index = lblock >> l2BlocksPerPage;
 613         page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
 614         if ((page_offset + size) > PAGE_CACHE_SIZE) {
 615                 jfs_err("MetaData crosses page boundary!!");
 616                 jfs_err("lblock = %lx, size  = %d", lblock, size);
 617                 dump_stack();
 618                 return NULL;
 619         }
 620         if (absolute)
 621                 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
 622         else {
 623                 /*
 624                  * If an nfs client tries to read an inode that is larger
 625                  * than any existing inodes, we may try to read past the
 626                  * end of the inode map
 627                  */
 628                 if ((lblock << inode->i_blkbits) >= inode->i_size)
 629                         return NULL;
 630                 mapping = inode->i_mapping;
 631         }
 632
 633         if (new && (PSIZE == PAGE_CACHE_SIZE)) {
 634                 page = grab_cache_page(mapping, page_index);
 635                 if (!page) {
 636                         jfs_err("grab_cache_page failed!");
 637                         return NULL;
 638                 }
 639                 SetPageUptodate(page);
 640         } else {
 641                 page = read_cache_page(mapping, page_index,
 642                             (filler_t *)mapping->a_ops->readpage, NULL);
 643                 if (IS_ERR(page) || !PageUptodate(page)) {
 644                         jfs_err("read_cache_page failed!");
 645                         return NULL;
 646                 }
 647                 lock_page(page);
 648         }
 649
 650         mp = page_to_mp(page, page_offset);
 651         if (mp) {
 652                 if (mp->logical_size != size) {
 653                         jfs_error(inode->i_sb,
 654                                   "__get_metapage: mp->logical_size != size");
 655                         jfs_err("logical_size = %d, size = %d",
 656                                 mp->logical_size, size);
 657                         dump_stack();
 658                         goto unlock;
 659                 }
 660                 mp->count++;
 661                 lock_metapage(mp);
 662                 if (test_bit(META_discard, &mp->flag)) {
 663                         if (!new) {
 664                                 jfs_error(inode->i_sb,
 665                                           "__get_metapage: using a "
 666                                           "discarded metapage");
 667                                 discard_metapage(mp);
 668                                 goto unlock;
 669                         }
 670                         clear_bit(META_discard, &mp->flag);
 671                 }
 672         } else {
 673                 INCREMENT(mpStat.pagealloc);
 674                 mp = alloc_metapage(GFP_NOFS);
 675                 mp->page = page;
 676                 mp->flag = 0;
 677                 mp->xflag = COMMIT_PAGE;
 678                 mp->count = 1;
 679                 mp->nohomeok = 0;
 680                 mp->logical_size = size;
 681                 mp->data = page_address(page) + page_offset;
 682                 mp->index = lblock;
 683                 if (unlikely(insert_metapage(page, mp))) {
 684                         free_metapage(mp);
 685                         goto unlock;
 686                 }
 687                 lock_metapage(mp);
 688         }
 689
 690         if (new) {
 691                 jfs_info("zeroing mp = 0x%p", mp);
 692                 memset(mp->data, 0, PSIZE);
 693         }
 694
 695         unlock_page(page);
 696         jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
 697         return mp;
 698
 699 unlock:
 700         unlock_page(page);
 701         return NULL;
 702 }
 703
 704 void grab_metapage(struct metapage * mp)
 705 {
 706         jfs_info("grab_metapage: mp = 0x%p", mp);
 707         page_cache_get(mp->page);
 708         lock_page(mp->page);
 709         mp->count++;
 710         lock_metapage(mp);
 711         unlock_page(mp->page);
 712 }
 713
 714 void force_metapage(struct metapage *mp)
 715 {
 716         struct page *page = mp->page;
 717         jfs_info("force_metapage: mp = 0x%p", mp);
 718         set_bit(META_forcewrite, &mp->flag);
 719         clear_bit(META_sync, &mp->flag);
 720         page_cache_get(page);
 721         lock_page(page);
 722         set_page_dirty(page);
 723         write_one_page(page, 1);
 724         clear_bit(META_forcewrite, &mp->flag);
 725         page_cache_release(page);
 726 }
 727
 728 void hold_metapage(struct metapage *mp)
 729 {
 730         lock_page(mp->page);
 731 }
 732
 733 void put_metapage(struct metapage *mp)
 734 {
 735         if (mp->count || mp->nohomeok) {
 736                 /* Someone else will release this */
 737                 unlock_page(mp->page);
 738                 return;
 739         }
 740         page_cache_get(mp->page);
 741         mp->count++;
 742         lock_metapage(mp);
 743         unlock_page(mp->page);
 744         release_metapage(mp);
 745 }
 746
 747 void release_metapage(struct metapage * mp)
 748 {
 749         struct page *page = mp->page;
 750         jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
 751
 752         BUG_ON(!page);
 753
 754         lock_page(page);
 755         unlock_metapage(mp);
 756
 757         assert(mp->count);
 758         if (--mp->count || mp->nohomeok) {
 759                 unlock_page(page);
 760                 page_cache_release(page);
 761                 return;
 762         }
 763
 764         if (test_bit(META_dirty, &mp->flag)) {
 765                 set_page_dirty(page);
 766                 if (test_bit(META_sync, &mp->flag)) {
 767                         clear_bit(META_sync, &mp->flag);
 768                         write_one_page(page, 1);
 769                         lock_page(page); /* write_one_page unlocks the page */
 770                 }
 771         } else if (mp->lsn)     /* discard_metapage doesn't remove it */
 772                 remove_from_logsync(mp);
 773
 774 #if MPS_PER_PAGE == 1
 775         /*
 776          * If we know this is the only thing in the page, we can throw
 777          * the page out of the page cache.  If pages are larger, we
 778          * don't want to do this.
 779          */
 780
 781         /* Retest mp->count since we may have released page lock */
 782         if (test_bit(META_discard, &mp->flag) && !mp->count) {
 783                 clear_page_dirty(page);
 784                 ClearPageUptodate(page);
 785         }
 786 #else
 787         /* Try to keep metapages from using up too much memory */
 788         drop_metapage(page, mp);
 789 #endif
 790         unlock_page(page);
 791         page_cache_release(page);
 792 }
 793
 794 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 795 {
 796         sector_t lblock;
 797         int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
 798         int BlocksPerPage = 1 << l2BlocksPerPage;
 799         /* All callers are interested in block device's mapping */
 800         struct address_space *mapping =
 801                 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
 802         struct metapage *mp;
 803         struct page *page;
 804         unsigned int offset;
 805
 806         /*
 807          * Mark metapages to discard.  They will eventually be
 808          * released, but should not be written.
 809          */
 810         for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
 811              lblock += BlocksPerPage) {
 812                 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
 813                 if (!page)
 814                         continue;
 815                 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 816                         mp = page_to_mp(page, offset);
 817                         if (!mp)
 818                                 continue;
 819                         if (mp->index < addr)
 820                                 continue;
 821                         if (mp->index >= addr + len)
 822                                 break;
 823
 824                         clear_bit(META_dirty, &mp->flag);
 825                         set_bit(META_discard, &mp->flag);
 826                         if (mp->lsn)
 827                                 remove_from_logsync(mp);
 828                 }
 829                 unlock_page(page);
 830                 page_cache_release(page);
 831         }
 832 }
 833
 834 #ifdef CONFIG_JFS_STATISTICS
 835 int jfs_mpstat_read(char *buffer, char **start, off_t offset, int length,
 836                     int *eof, void *data)
 837 {
 838         int len = 0;
 839         off_t begin;
 840
 841         len += sprintf(buffer,
 842                        "JFS Metapage statistics\n"
 843                        "=======================\n"
 844                        "page allocations = %d\n"
 845                        "page frees = %d\n"
 846                        "lock waits = %d\n",
 847                        mpStat.pagealloc,
 848                        mpStat.pagefree,
 849                        mpStat.lockwait);
 850
 851         begin = offset;
 852         *start = buffer + begin;
 853         len -= begin;
 854
 855         if (len > length)
 856                 len = length;
 857         else
 858                 *eof = 1;
 859
 860         if (len < 0)
 861                 len = 0;
 862
 863         return len;
 864 }
 865 #endif