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/module.h>
  23 #include <linux/bio.h>
  24 #include <linux/init.h>
  25 #include <linux/buffer_head.h>
  26 #include <linux/mempool.h>
  27 #include <linux/seq_file.h>
  28 #include "jfs_incore.h"
  29 #include "jfs_superblock.h"
  30 #include "jfs_filsys.h"
  31 #include "jfs_metapage.h"
  32 #include "jfs_txnmgr.h"
  33 #include "jfs_debug.h"
  34
  35 #ifdef CONFIG_JFS_STATISTICS
  36 static struct {
  37         uint    pagealloc;      /* # of page allocations */
  38         uint    pagefree;       /* # of page frees */
  39         uint    lockwait;       /* # of sleeping lock_metapage() calls */
  40 } mpStat;
  41 #endif
  42
  43 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
  44 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
  45
  46 static inline void unlock_metapage(struct metapage *mp)
  47 {
  48         clear_bit_unlock(META_locked, &mp->flag);
  49         wake_up(&mp->wait);
  50 }
  51
  52 static inline void __lock_metapage(struct metapage *mp)
  53 {
  54         DECLARE_WAITQUEUE(wait, current);
  55         INCREMENT(mpStat.lockwait);
  56         add_wait_queue_exclusive(&mp->wait, &wait);
  57         do {
  58                 set_current_state(TASK_UNINTERRUPTIBLE);
  59                 if (metapage_locked(mp)) {
  60                         unlock_page(mp->page);
  61                         io_schedule();
  62                         lock_page(mp->page);
  63                 }
  64         } while (trylock_metapage(mp));
  65         __set_current_state(TASK_RUNNING);
  66         remove_wait_queue(&mp->wait, &wait);
  67 }
  68
  69 /*
  70  * Must have mp->page locked
  71  */
  72 static inline void lock_metapage(struct metapage *mp)
  73 {
  74         if (trylock_metapage(mp))
  75                 __lock_metapage(mp);
  76 }
  77
  78 #define METAPOOL_MIN_PAGES 32
  79 static struct kmem_cache *metapage_cache;
  80 static mempool_t *metapage_mempool;
  81
  82 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
  83
  84 #if MPS_PER_PAGE > 1
  85
  86 struct meta_anchor {
  87         int mp_count;
  88         atomic_t io_count;
  89         struct metapage *mp[MPS_PER_PAGE];
  90 };
  91 #define mp_anchor(page) ((struct meta_anchor *)page_private(page))
  92
  93 static inline struct metapage *page_to_mp(struct page *page, int offset)
  94 {
  95         if (!PagePrivate(page))
  96                 return NULL;
  97         return mp_anchor(page)->mp[offset >> L2PSIZE];
  98 }
  99
 100 static inline int insert_metapage(struct page *page, struct metapage *mp)
 101 {
 102         struct meta_anchor *a;
 103         int index;
 104         int l2mp_blocks;        /* log2 blocks per metapage */
 105
 106         if (PagePrivate(page))
 107                 a = mp_anchor(page);
 108         else {
 109                 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
 110                 if (!a)
 111                         return -ENOMEM;
 112                 set_page_private(page, (unsigned long)a);
 113                 SetPagePrivate(page);
 114                 kmap(page);
 115         }
 116
 117         if (mp) {
 118                 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
 119                 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 120                 a->mp_count++;
 121                 a->mp[index] = mp;
 122         }
 123
 124         return 0;
 125 }
 126
 127 static inline void remove_metapage(struct page *page, struct metapage *mp)
 128 {
 129         struct meta_anchor *a = mp_anchor(page);
 130         int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
 131         int index;
 132
 133         index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 134
 135         BUG_ON(a->mp[index] != mp);
 136
 137         a->mp[index] = NULL;
 138         if (--a->mp_count == 0) {
 139                 kfree(a);
 140                 set_page_private(page, 0);
 141                 ClearPagePrivate(page);
 142                 kunmap(page);
 143         }
 144 }
 145
 146 static inline void inc_io(struct page *page)
 147 {
 148         atomic_inc(&mp_anchor(page)->io_count);
 149 }
 150
 151 static inline void dec_io(struct page *page, void (*handler) (struct page *))
 152 {
 153         if (atomic_dec_and_test(&mp_anchor(page)->io_count))
 154                 handler(page);
 155 }
 156
 157 #else
 158 static inline struct metapage *page_to_mp(struct page *page, int offset)
 159 {
 160         return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
 161 }
 162
 163 static inline int insert_metapage(struct page *page, struct metapage *mp)
 164 {
 165         if (mp) {
 166                 set_page_private(page, (unsigned long)mp);
 167                 SetPagePrivate(page);
 168                 kmap(page);
 169         }
 170         return 0;
 171 }
 172
 173 static inline void remove_metapage(struct page *page, struct metapage *mp)
 174 {
 175         set_page_private(page, 0);
 176         ClearPagePrivate(page);
 177         kunmap(page);
 178 }
 179
 180 #define inc_io(page) do {} while(0)
 181 #define dec_io(page, handler) handler(page)
 182
 183 #endif
 184
 185 static void init_once(void *foo)
 186 {
 187         struct metapage *mp = (struct metapage *)foo;
 188
 189         mp->lid = 0;
 190         mp->lsn = 0;
 191         mp->flag = 0;
 192         mp->data = NULL;
 193         mp->clsn = 0;
 194         mp->log = NULL;
 195         set_bit(META_free, &mp->flag);
 196         init_waitqueue_head(&mp->wait);
 197 }
 198
 199 static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
 200 {
 201         return mempool_alloc(metapage_mempool, gfp_mask);
 202 }
 203
 204 static inline void free_metapage(struct metapage *mp)
 205 {
 206         mp->flag = 0;
 207         set_bit(META_free, &mp->flag);
 208
 209         mempool_free(mp, metapage_mempool);
 210 }
 211
 212 int __init metapage_init(void)
 213 {
 214         /*
 215          * Allocate the metapage structures
 216          */
 217         metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
 218                                            0, 0, init_once);
 219         if (metapage_cache == NULL)
 220                 return -ENOMEM;
 221
 222         metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
 223                                                     metapage_cache);
 224
 225         if (metapage_mempool == NULL) {
 226                 kmem_cache_destroy(metapage_cache);
 227                 return -ENOMEM;
 228         }
 229
 230         return 0;
 231 }
 232
 233 void metapage_exit(void)
 234 {
 235         mempool_destroy(metapage_mempool);
 236         kmem_cache_destroy(metapage_cache);
 237 }
 238
 239 static inline void drop_metapage(struct page *page, struct metapage *mp)
 240 {
 241         if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
 242             test_bit(META_io, &mp->flag))
 243                 return;
 244         remove_metapage(page, mp);
 245         INCREMENT(mpStat.pagefree);
 246         free_metapage(mp);
 247 }
 248
 249 /*
 250  * Metapage address space operations
 251  */
 252
 253 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
 254                                     int *len)
 255 {
 256         int rc = 0;
 257         int xflag;
 258         s64 xaddr;
 259         sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
 260                                inode->i_blkbits;
 261
 262         if (lblock >= file_blocks)
 263                 return 0;
 264         if (lblock + *len > file_blocks)
 265                 *len = file_blocks - lblock;
 266
 267         if (inode->i_ino) {
 268                 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
 269                 if ((rc == 0) && *len)
 270                         lblock = (sector_t)xaddr;
 271                 else
 272                         lblock = 0;
 273         } /* else no mapping */
 274
 275         return lblock;
 276 }
 277
 278 static void last_read_complete(struct page *page)
 279 {
 280         if (!PageError(page))
 281                 SetPageUptodate(page);
 282         unlock_page(page);
 283 }
 284
 285 static void metapage_read_end_io(struct bio *bio, int err)
 286 {
 287         struct page *page = bio->bi_private;
 288
 289         if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 290                 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
 291                 SetPageError(page);
 292         }
 293
 294         dec_io(page, last_read_complete);
 295         bio_put(bio);
 296 }
 297
 298 static void remove_from_logsync(struct metapage *mp)
 299 {
 300         struct jfs_log *log = mp->log;
 301         unsigned long flags;
 302 /*
 303  * This can race.  Recheck that log hasn't been set to null, and after
 304  * acquiring logsync lock, recheck lsn
 305  */
 306         if (!log)
 307                 return;
 308
 309         LOGSYNC_LOCK(log, flags);
 310         if (mp->lsn) {
 311                 mp->log = NULL;
 312                 mp->lsn = 0;
 313                 mp->clsn = 0;
 314                 log->count--;
 315                 list_del(&mp->synclist);
 316         }
 317         LOGSYNC_UNLOCK(log, flags);
 318 }
 319
 320 static void last_write_complete(struct page *page)
 321 {
 322         struct metapage *mp;
 323         unsigned int offset;
 324
 325         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 326                 mp = page_to_mp(page, offset);
 327                 if (mp && test_bit(META_io, &mp->flag)) {
 328                         if (mp->lsn)
 329                                 remove_from_logsync(mp);
 330                         clear_bit(META_io, &mp->flag);
 331                 }
 332                 /*
 333                  * I'd like to call drop_metapage here, but I don't think it's
 334                  * safe unless I have the page locked
 335                  */
 336         }
 337         end_page_writeback(page);
 338 }
 339
 340 static void metapage_write_end_io(struct bio *bio, int err)
 341 {
 342         struct page *page = bio->bi_private;
 343
 344         BUG_ON(!PagePrivate(page));
 345
 346         if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 347                 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
 348                 SetPageError(page);
 349         }
 350         dec_io(page, last_write_complete);
 351         bio_put(bio);
 352 }
 353
 354 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 355 {
 356         struct bio *bio = NULL;
 357         int block_offset;       /* block offset of mp within page */
 358         struct inode *inode = page->mapping->host;
 359         int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
 360         int len;
 361         int xlen;
 362         struct metapage *mp;
 363         int redirty = 0;
 364         sector_t lblock;
 365         int nr_underway = 0;
 366         sector_t pblock;
 367         sector_t next_block = 0;
 368         sector_t page_start;
 369         unsigned long bio_bytes = 0;
 370         unsigned long bio_offset = 0;
 371         int offset;
 372         int bad_blocks = 0;
 373
 374         page_start = (sector_t)page->index <<
 375                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
 376         BUG_ON(!PageLocked(page));
 377         BUG_ON(PageWriteback(page));
 378         set_page_writeback(page);
 379
 380         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 381                 mp = page_to_mp(page, offset);
 382
 383                 if (!mp || !test_bit(META_dirty, &mp->flag))
 384                         continue;
 385
 386                 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
 387                         redirty = 1;
 388                         /*
 389                          * Make sure this page isn't blocked indefinitely.
 390                          * If the journal isn't undergoing I/O, push it
 391                          */
 392                         if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
 393                                 jfs_flush_journal(mp->log, 0);
 394                         continue;
 395                 }
 396
 397                 clear_bit(META_dirty, &mp->flag);
 398                 set_bit(META_io, &mp->flag);
 399                 block_offset = offset >> inode->i_blkbits;
 400                 lblock = page_start + block_offset;
 401                 if (bio) {
 402                         if (xlen && lblock == next_block) {
 403                                 /* Contiguous, in memory & on disk */
 404                                 len = min(xlen, blocks_per_mp);
 405                                 xlen -= len;
 406                                 bio_bytes += len << inode->i_blkbits;
 407                                 continue;
 408                         }
 409                         /* Not contiguous */
 410                         if (bio_add_page(bio, page, bio_bytes, bio_offset) <
 411                             bio_bytes)
 412                                 goto add_failed;
 413                         /*
 414                          * Increment counter before submitting i/o to keep
 415                          * count from hitting zero before we're through
 416                          */
 417                         inc_io(page);
 418                         if (!bio->bi_size)
 419                                 goto dump_bio;
 420                         submit_bio(WRITE, bio);
 421                         nr_underway++;
 422                         bio = NULL;
 423                 } else
 424                         inc_io(page);
 425                 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
 426                 pblock = metapage_get_blocks(inode, lblock, &xlen);
 427                 if (!pblock) {
 428                         printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
 429                         /*
 430                          * We already called inc_io(), but can't cancel it
 431                          * with dec_io() until we're done with the page
 432                          */
 433                         bad_blocks++;
 434                         continue;
 435                 }
 436                 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
 437
 438                 bio = bio_alloc(GFP_NOFS, 1);
 439                 bio->bi_bdev = inode->i_sb->s_bdev;
 440                 bio->bi_sector = pblock << (inode->i_blkbits - 9);
 441                 bio->bi_end_io = metapage_write_end_io;
 442                 bio->bi_private = page;
 443
 444                 /* Don't call bio_add_page yet, we may add to this vec */
 445                 bio_offset = offset;
 446                 bio_bytes = len << inode->i_blkbits;
 447
 448                 xlen -= len;
 449                 next_block = lblock + len;
 450         }
 451         if (bio) {
 452                 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
 453                                 goto add_failed;
 454                 if (!bio->bi_size)
 455                         goto dump_bio;
 456
 457                 submit_bio(WRITE, bio);
 458                 nr_underway++;
 459         }
 460         if (redirty)
 461                 redirty_page_for_writepage(wbc, page);
 462
 463         unlock_page(page);
 464
 465         if (bad_blocks)
 466                 goto err_out;
 467
 468         if (nr_underway == 0)
 469                 end_page_writeback(page);
 470
 471         return 0;
 472 add_failed:
 473         /* We should never reach here, since we're only adding one vec */
 474         printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
 475         goto skip;
 476 dump_bio:
 477         print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
 478                        4, bio, sizeof(*bio), 0);
 479 skip:
 480         bio_put(bio);
 481         unlock_page(page);
 482         dec_io(page, last_write_complete);
 483 err_out:
 484         while (bad_blocks--)
 485                 dec_io(page, last_write_complete);
 486         return -EIO;
 487 }
 488
 489 static int metapage_readpage(struct file *fp, struct page *page)
 490 {
 491         struct inode *inode = page->mapping->host;
 492         struct bio *bio = NULL;
 493         int block_offset;
 494         int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
 495         sector_t page_start;    /* address of page in fs blocks */
 496         sector_t pblock;
 497         int xlen;
 498         unsigned int len;
 499         int offset;
 500
 501         BUG_ON(!PageLocked(page));
 502         page_start = (sector_t)page->index <<
 503                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
 504
 505         block_offset = 0;
 506         while (block_offset < blocks_per_page) {
 507                 xlen = blocks_per_page - block_offset;
 508                 pblock = metapage_get_blocks(inode, page_start + block_offset,
 509                                              &xlen);
 510                 if (pblock) {
 511                         if (!PagePrivate(page))
 512                                 insert_metapage(page, NULL);
 513                         inc_io(page);
 514                         if (bio)
 515                                 submit_bio(READ, bio);
 516
 517                         bio = bio_alloc(GFP_NOFS, 1);
 518                         bio->bi_bdev = inode->i_sb->s_bdev;
 519                         bio->bi_sector = pblock << (inode->i_blkbits - 9);
 520                         bio->bi_end_io = metapage_read_end_io;
 521                         bio->bi_private = page;
 522                         len = xlen << inode->i_blkbits;
 523                         offset = block_offset << inode->i_blkbits;
 524                         if (bio_add_page(bio, page, len, offset) < len)
 525                                 goto add_failed;
 526                         block_offset += xlen;
 527                 } else
 528                         block_offset++;
 529         }
 530         if (bio)
 531                 submit_bio(READ, bio);
 532         else
 533                 unlock_page(page);
 534
 535         return 0;
 536
 537 add_failed:
 538         printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
 539         bio_put(bio);
 540         dec_io(page, last_read_complete);
 541         return -EIO;
 542 }
 543
 544 static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
 545 {
 546         struct metapage *mp;
 547         int ret = 1;
 548         int offset;
 549
 550         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 551                 mp = page_to_mp(page, offset);
 552
 553                 if (!mp)
 554                         continue;
 555
 556                 jfs_info("metapage_releasepage: mp = 0x%p", mp);
 557                 if (mp->count || mp->nohomeok ||
 558                     test_bit(META_dirty, &mp->flag)) {
 559                         jfs_info("count = %ld, nohomeok = %d", mp->count,
 560                                  mp->nohomeok);
 561                         ret = 0;
 562                         continue;
 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         return ret;
 571 }
 572
 573 static void metapage_invalidatepage(struct page *page, unsigned long offset)
 574 {
 575         BUG_ON(offset);
 576
 577         BUG_ON(PageWriteback(page));
 578
 579         metapage_releasepage(page, 0);
 580 }
 581
 582 const struct address_space_operations jfs_metapage_aops = {
 583         .readpage       = metapage_readpage,
 584         .writepage      = metapage_writepage,
 585         .sync_page      = block_sync_page,
 586         .releasepage    = metapage_releasepage,
 587         .invalidatepage = metapage_invalidatepage,
 588         .set_page_dirty = __set_page_dirty_nobuffers,
 589 };
 590
 591 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 592                                 unsigned int size, int absolute,
 593                                 unsigned long new)
 594 {
 595         int l2BlocksPerPage;
 596         int l2bsize;
 597         struct address_space *mapping;
 598         struct metapage *mp = NULL;
 599         struct page *page;
 600         unsigned long page_index;
 601         unsigned long page_offset;
 602
 603         jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
 604                  inode->i_ino, lblock, absolute);
 605
 606         l2bsize = inode->i_blkbits;
 607         l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
 608         page_index = lblock >> l2BlocksPerPage;
 609         page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
 610         if ((page_offset + size) > PAGE_CACHE_SIZE) {
 611                 jfs_err("MetaData crosses page boundary!!");
 612                 jfs_err("lblock = %lx, size  = %d", lblock, size);
 613                 dump_stack();
 614                 return NULL;
 615         }
 616         if (absolute)
 617                 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
 618         else {
 619                 /*
 620                  * If an nfs client tries to read an inode that is larger
 621                  * than any existing inodes, we may try to read past the
 622                  * end of the inode map
 623                  */
 624                 if ((lblock << inode->i_blkbits) >= inode->i_size)
 625                         return NULL;
 626                 mapping = inode->i_mapping;
 627         }
 628
 629         if (new && (PSIZE == PAGE_CACHE_SIZE)) {
 630                 page = grab_cache_page(mapping, page_index);
 631                 if (!page) {
 632                         jfs_err("grab_cache_page failed!");
 633                         return NULL;
 634                 }
 635                 SetPageUptodate(page);
 636         } else {
 637                 page = read_mapping_page(mapping, page_index, NULL);
 638                 if (IS_ERR(page) || !PageUptodate(page)) {
 639                         jfs_err("read_mapping_page failed!");
 640                         return NULL;
 641                 }
 642                 lock_page(page);
 643         }
 644
 645         mp = page_to_mp(page, page_offset);
 646         if (mp) {
 647                 if (mp->logical_size != size) {
 648                         jfs_error(inode->i_sb,
 649                                   "__get_metapage: mp->logical_size != size");
 650                         jfs_err("logical_size = %d, size = %d",
 651                                 mp->logical_size, size);
 652                         dump_stack();
 653                         goto unlock;
 654                 }
 655                 mp->count++;
 656                 lock_metapage(mp);
 657                 if (test_bit(META_discard, &mp->flag)) {
 658                         if (!new) {
 659                                 jfs_error(inode->i_sb,
 660                                           "__get_metapage: using a "
 661                                           "discarded metapage");
 662                                 discard_metapage(mp);
 663                                 goto unlock;
 664                         }
 665                         clear_bit(META_discard, &mp->flag);
 666                 }
 667         } else {
 668                 INCREMENT(mpStat.pagealloc);
 669                 mp = alloc_metapage(GFP_NOFS);
 670                 mp->page = page;
 671                 mp->flag = 0;
 672                 mp->xflag = COMMIT_PAGE;
 673                 mp->count = 1;
 674                 mp->nohomeok = 0;
 675                 mp->logical_size = size;
 676                 mp->data = page_address(page) + page_offset;
 677                 mp->index = lblock;
 678                 if (unlikely(insert_metapage(page, mp))) {
 679                         free_metapage(mp);
 680                         goto unlock;
 681                 }
 682                 lock_metapage(mp);
 683         }
 684
 685         if (new) {
 686                 jfs_info("zeroing mp = 0x%p", mp);
 687                 memset(mp->data, 0, PSIZE);
 688         }
 689
 690         unlock_page(page);
 691         jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
 692         return mp;
 693
 694 unlock:
 695         unlock_page(page);
 696         return NULL;
 697 }
 698
 699 void grab_metapage(struct metapage * mp)
 700 {
 701         jfs_info("grab_metapage: mp = 0x%p", mp);
 702         page_cache_get(mp->page);
 703         lock_page(mp->page);
 704         mp->count++;
 705         lock_metapage(mp);
 706         unlock_page(mp->page);
 707 }
 708
 709 void force_metapage(struct metapage *mp)
 710 {
 711         struct page *page = mp->page;
 712         jfs_info("force_metapage: mp = 0x%p", mp);
 713         set_bit(META_forcewrite, &mp->flag);
 714         clear_bit(META_sync, &mp->flag);
 715         page_cache_get(page);
 716         lock_page(page);
 717         set_page_dirty(page);
 718         write_one_page(page, 1);
 719         clear_bit(META_forcewrite, &mp->flag);
 720         page_cache_release(page);
 721 }
 722
 723 void hold_metapage(struct metapage *mp)
 724 {
 725         lock_page(mp->page);
 726 }
 727
 728 void put_metapage(struct metapage *mp)
 729 {
 730         if (mp->count || mp->nohomeok) {
 731                 /* Someone else will release this */
 732                 unlock_page(mp->page);
 733                 return;
 734         }
 735         page_cache_get(mp->page);
 736         mp->count++;
 737         lock_metapage(mp);
 738         unlock_page(mp->page);
 739         release_metapage(mp);
 740 }
 741
 742 void release_metapage(struct metapage * mp)
 743 {
 744         struct page *page = mp->page;
 745         jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
 746
 747         BUG_ON(!page);
 748
 749         lock_page(page);
 750         unlock_metapage(mp);
 751
 752         assert(mp->count);
 753         if (--mp->count || mp->nohomeok) {
 754                 unlock_page(page);
 755                 page_cache_release(page);
 756                 return;
 757         }
 758
 759         if (test_bit(META_dirty, &mp->flag)) {
 760                 set_page_dirty(page);
 761                 if (test_bit(META_sync, &mp->flag)) {
 762                         clear_bit(META_sync, &mp->flag);
 763                         write_one_page(page, 1);
 764                         lock_page(page); /* write_one_page unlocks the page */
 765                 }
 766         } else if (mp->lsn)     /* discard_metapage doesn't remove it */
 767                 remove_from_logsync(mp);
 768
 769         /* Try to keep metapages from using up too much memory */
 770         drop_metapage(page, mp);
 771
 772         unlock_page(page);
 773         page_cache_release(page);
 774 }
 775
 776 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 777 {
 778         sector_t lblock;
 779         int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
 780         int BlocksPerPage = 1 << l2BlocksPerPage;
 781         /* All callers are interested in block device's mapping */
 782         struct address_space *mapping =
 783                 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
 784         struct metapage *mp;
 785         struct page *page;
 786         unsigned int offset;
 787
 788         /*
 789          * Mark metapages to discard.  They will eventually be
 790          * released, but should not be written.
 791          */
 792         for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
 793              lblock += BlocksPerPage) {
 794                 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
 795                 if (!page)
 796                         continue;
 797                 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 798                         mp = page_to_mp(page, offset);
 799                         if (!mp)
 800                                 continue;
 801                         if (mp->index < addr)
 802                                 continue;
 803                         if (mp->index >= addr + len)
 804                                 break;
 805
 806                         clear_bit(META_dirty, &mp->flag);
 807                         set_bit(META_discard, &mp->flag);
 808                         if (mp->lsn)
 809                                 remove_from_logsync(mp);
 810                 }
 811                 unlock_page(page);
 812                 page_cache_release(page);
 813         }
 814 }
 815
 816 #ifdef CONFIG_JFS_STATISTICS
 817 static int jfs_mpstat_proc_show(struct seq_file *m, void *v)
 818 {
 819         seq_printf(m,
 820                        "JFS Metapage statistics\n"
 821                        "=======================\n"
 822                        "page allocations = %d\n"
 823                        "page frees = %d\n"
 824                        "lock waits = %d\n",
 825                        mpStat.pagealloc,
 826                        mpStat.pagefree,
 827                        mpStat.lockwait);
 828         return 0;
 829 }
 830
 831 static int jfs_mpstat_proc_open(struct inode *inode, struct file *file)
 832 {
 833         return single_open(file, jfs_mpstat_proc_show, NULL);
 834 }
 835
 836 const struct file_operations jfs_mpstat_proc_fops = {
 837         .owner          = THIS_MODULE,
 838         .open           = jfs_mpstat_proc_open,
 839         .read           = seq_read,
 840         .llseek         = seq_lseek,
 841         .release        = single_release,
 842 };
 843 #endif