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/slab.h>
  25 #include <linux/init.h>
  26 #include <linux/buffer_head.h>
  27 #include <linux/mempool.h>
  28 #include <linux/seq_file.h>
  29 #include "jfs_incore.h"
  30 #include "jfs_superblock.h"
  31 #include "jfs_filsys.h"
  32 #include "jfs_metapage.h"
  33 #include "jfs_txnmgr.h"
  34 #include "jfs_debug.h"
  35
  36 #ifdef CONFIG_JFS_STATISTICS
  37 static struct {
  38         uint    pagealloc;      /* # of page allocations */
  39         uint    pagefree;       /* # of page frees */
  40         uint    lockwait;       /* # of sleeping lock_metapage() calls */
  41 } mpStat;
  42 #endif
  43
  44 #define metapage_locked(mp) test_bit(META_locked, &(mp)->flag)
  45 #define trylock_metapage(mp) test_and_set_bit_lock(META_locked, &(mp)->flag)
  46
  47 static inline void unlock_metapage(struct metapage *mp)
  48 {
  49         clear_bit_unlock(META_locked, &mp->flag);
  50         wake_up(&mp->wait);
  51 }
  52
  53 static inline void __lock_metapage(struct metapage *mp)
  54 {
  55         DECLARE_WAITQUEUE(wait, current);
  56         INCREMENT(mpStat.lockwait);
  57         add_wait_queue_exclusive(&mp->wait, &wait);
  58         do {
  59                 set_current_state(TASK_UNINTERRUPTIBLE);
  60                 if (metapage_locked(mp)) {
  61                         unlock_page(mp->page);
  62                         io_schedule();
  63                         lock_page(mp->page);
  64                 }
  65         } while (trylock_metapage(mp));
  66         __set_current_state(TASK_RUNNING);
  67         remove_wait_queue(&mp->wait, &wait);
  68 }
  69
  70 /*
  71  * Must have mp->page locked
  72  */
  73 static inline void lock_metapage(struct metapage *mp)
  74 {
  75         if (trylock_metapage(mp))
  76                 __lock_metapage(mp);
  77 }
  78
  79 #define METAPOOL_MIN_PAGES 32
  80 static struct kmem_cache *metapage_cache;
  81 static mempool_t *metapage_mempool;
  82
  83 #define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
  84
  85 #if MPS_PER_PAGE > 1
  86
  87 struct meta_anchor {
  88         int mp_count;
  89         atomic_t io_count;
  90         struct metapage *mp[MPS_PER_PAGE];
  91 };
  92 #define mp_anchor(page) ((struct meta_anchor *)page_private(page))
  93
  94 static inline struct metapage *page_to_mp(struct page *page, int offset)
  95 {
  96         if (!PagePrivate(page))
  97                 return NULL;
  98         return mp_anchor(page)->mp[offset >> L2PSIZE];
  99 }
 100
 101 static inline int insert_metapage(struct page *page, struct metapage *mp)
 102 {
 103         struct meta_anchor *a;
 104         int index;
 105         int l2mp_blocks;        /* log2 blocks per metapage */
 106
 107         if (PagePrivate(page))
 108                 a = mp_anchor(page);
 109         else {
 110                 a = kzalloc(sizeof(struct meta_anchor), GFP_NOFS);
 111                 if (!a)
 112                         return -ENOMEM;
 113                 set_page_private(page, (unsigned long)a);
 114                 SetPagePrivate(page);
 115                 kmap(page);
 116         }
 117
 118         if (mp) {
 119                 l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
 120                 index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 121                 a->mp_count++;
 122                 a->mp[index] = mp;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static inline void remove_metapage(struct page *page, struct metapage *mp)
 129 {
 130         struct meta_anchor *a = mp_anchor(page);
 131         int l2mp_blocks = L2PSIZE - page->mapping->host->i_blkbits;
 132         int index;
 133
 134         index = (mp->index >> l2mp_blocks) & (MPS_PER_PAGE - 1);
 135
 136         BUG_ON(a->mp[index] != mp);
 137
 138         a->mp[index] = NULL;
 139         if (--a->mp_count == 0) {
 140                 kfree(a);
 141                 set_page_private(page, 0);
 142                 ClearPagePrivate(page);
 143                 kunmap(page);
 144         }
 145 }
 146
 147 static inline void inc_io(struct page *page)
 148 {
 149         atomic_inc(&mp_anchor(page)->io_count);
 150 }
 151
 152 static inline void dec_io(struct page *page, void (*handler) (struct page *))
 153 {
 154         if (atomic_dec_and_test(&mp_anchor(page)->io_count))
 155                 handler(page);
 156 }
 157
 158 #else
 159 static inline struct metapage *page_to_mp(struct page *page, int offset)
 160 {
 161         return PagePrivate(page) ? (struct metapage *)page_private(page) : NULL;
 162 }
 163
 164 static inline int insert_metapage(struct page *page, struct metapage *mp)
 165 {
 166         if (mp) {
 167                 set_page_private(page, (unsigned long)mp);
 168                 SetPagePrivate(page);
 169                 kmap(page);
 170         }
 171         return 0;
 172 }
 173
 174 static inline void remove_metapage(struct page *page, struct metapage *mp)
 175 {
 176         set_page_private(page, 0);
 177         ClearPagePrivate(page);
 178         kunmap(page);
 179 }
 180
 181 #define inc_io(page) do {} while(0)
 182 #define dec_io(page, handler) handler(page)
 183
 184 #endif
 185
 186 static void init_once(void *foo)
 187 {
 188         struct metapage *mp = (struct metapage *)foo;
 189
 190         mp->lid = 0;
 191         mp->lsn = 0;
 192         mp->flag = 0;
 193         mp->data = NULL;
 194         mp->clsn = 0;
 195         mp->log = NULL;
 196         set_bit(META_free, &mp->flag);
 197         init_waitqueue_head(&mp->wait);
 198 }
 199
 200 static inline struct metapage *alloc_metapage(gfp_t gfp_mask)
 201 {
 202         return mempool_alloc(metapage_mempool, gfp_mask);
 203 }
 204
 205 static inline void free_metapage(struct metapage *mp)
 206 {
 207         mp->flag = 0;
 208         set_bit(META_free, &mp->flag);
 209
 210         mempool_free(mp, metapage_mempool);
 211 }
 212
 213 int __init metapage_init(void)
 214 {
 215         /*
 216          * Allocate the metapage structures
 217          */
 218         metapage_cache = kmem_cache_create("jfs_mp", sizeof(struct metapage),
 219                                            0, 0, init_once);
 220         if (metapage_cache == NULL)
 221                 return -ENOMEM;
 222
 223         metapage_mempool = mempool_create_slab_pool(METAPOOL_MIN_PAGES,
 224                                                     metapage_cache);
 225
 226         if (metapage_mempool == NULL) {
 227                 kmem_cache_destroy(metapage_cache);
 228                 return -ENOMEM;
 229         }
 230
 231         return 0;
 232 }
 233
 234 void metapage_exit(void)
 235 {
 236         mempool_destroy(metapage_mempool);
 237         kmem_cache_destroy(metapage_cache);
 238 }
 239
 240 static inline void drop_metapage(struct page *page, struct metapage *mp)
 241 {
 242         if (mp->count || mp->nohomeok || test_bit(META_dirty, &mp->flag) ||
 243             test_bit(META_io, &mp->flag))
 244                 return;
 245         remove_metapage(page, mp);
 246         INCREMENT(mpStat.pagefree);
 247         free_metapage(mp);
 248 }
 249
 250 /*
 251  * Metapage address space operations
 252  */
 253
 254 static sector_t metapage_get_blocks(struct inode *inode, sector_t lblock,
 255                                     int *len)
 256 {
 257         int rc = 0;
 258         int xflag;
 259         s64 xaddr;
 260         sector_t file_blocks = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
 261                                inode->i_blkbits;
 262
 263         if (lblock >= file_blocks)
 264                 return 0;
 265         if (lblock + *len > file_blocks)
 266                 *len = file_blocks - lblock;
 267
 268         if (inode->i_ino) {
 269                 rc = xtLookup(inode, (s64)lblock, *len, &xflag, &xaddr, len, 0);
 270                 if ((rc == 0) && *len)
 271                         lblock = (sector_t)xaddr;
 272                 else
 273                         lblock = 0;
 274         } /* else no mapping */
 275
 276         return lblock;
 277 }
 278
 279 static void last_read_complete(struct page *page)
 280 {
 281         if (!PageError(page))
 282                 SetPageUptodate(page);
 283         unlock_page(page);
 284 }
 285
 286 static void metapage_read_end_io(struct bio *bio, int err)
 287 {
 288         struct page *page = bio->bi_private;
 289
 290         if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 291                 printk(KERN_ERR "metapage_read_end_io: I/O error\n");
 292                 SetPageError(page);
 293         }
 294
 295         dec_io(page, last_read_complete);
 296         bio_put(bio);
 297 }
 298
 299 static void remove_from_logsync(struct metapage *mp)
 300 {
 301         struct jfs_log *log = mp->log;
 302         unsigned long flags;
 303 /*
 304  * This can race.  Recheck that log hasn't been set to null, and after
 305  * acquiring logsync lock, recheck lsn
 306  */
 307         if (!log)
 308                 return;
 309
 310         LOGSYNC_LOCK(log, flags);
 311         if (mp->lsn) {
 312                 mp->log = NULL;
 313                 mp->lsn = 0;
 314                 mp->clsn = 0;
 315                 log->count--;
 316                 list_del(&mp->synclist);
 317         }
 318         LOGSYNC_UNLOCK(log, flags);
 319 }
 320
 321 static void last_write_complete(struct page *page)
 322 {
 323         struct metapage *mp;
 324         unsigned int offset;
 325
 326         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 327                 mp = page_to_mp(page, offset);
 328                 if (mp && test_bit(META_io, &mp->flag)) {
 329                         if (mp->lsn)
 330                                 remove_from_logsync(mp);
 331                         clear_bit(META_io, &mp->flag);
 332                 }
 333                 /*
 334                  * I'd like to call drop_metapage here, but I don't think it's
 335                  * safe unless I have the page locked
 336                  */
 337         }
 338         end_page_writeback(page);
 339 }
 340
 341 static void metapage_write_end_io(struct bio *bio, int err)
 342 {
 343         struct page *page = bio->bi_private;
 344
 345         BUG_ON(!PagePrivate(page));
 346
 347         if (! test_bit(BIO_UPTODATE, &bio->bi_flags)) {
 348                 printk(KERN_ERR "metapage_write_end_io: I/O error\n");
 349                 SetPageError(page);
 350         }
 351         dec_io(page, last_write_complete);
 352         bio_put(bio);
 353 }
 354
 355 static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 356 {
 357         struct bio *bio = NULL;
 358         int block_offset;       /* block offset of mp within page */
 359         struct inode *inode = page->mapping->host;
 360         int blocks_per_mp = JFS_SBI(inode->i_sb)->nbperpage;
 361         int len;
 362         int xlen;
 363         struct metapage *mp;
 364         int redirty = 0;
 365         sector_t lblock;
 366         int nr_underway = 0;
 367         sector_t pblock;
 368         sector_t next_block = 0;
 369         sector_t page_start;
 370         unsigned long bio_bytes = 0;
 371         unsigned long bio_offset = 0;
 372         int offset;
 373         int bad_blocks = 0;
 374
 375         page_start = (sector_t)page->index <<
 376                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
 377         BUG_ON(!PageLocked(page));
 378         BUG_ON(PageWriteback(page));
 379         set_page_writeback(page);
 380
 381         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 382                 mp = page_to_mp(page, offset);
 383
 384                 if (!mp || !test_bit(META_dirty, &mp->flag))
 385                         continue;
 386
 387                 if (mp->nohomeok && !test_bit(META_forcewrite, &mp->flag)) {
 388                         redirty = 1;
 389                         /*
 390                          * Make sure this page isn't blocked indefinitely.
 391                          * If the journal isn't undergoing I/O, push it
 392                          */
 393                         if (mp->log && !(mp->log->cflag & logGC_PAGEOUT))
 394                                 jfs_flush_journal(mp->log, 0);
 395                         continue;
 396                 }
 397
 398                 clear_bit(META_dirty, &mp->flag);
 399                 set_bit(META_io, &mp->flag);
 400                 block_offset = offset >> inode->i_blkbits;
 401                 lblock = page_start + block_offset;
 402                 if (bio) {
 403                         if (xlen && lblock == next_block) {
 404                                 /* Contiguous, in memory & on disk */
 405                                 len = min(xlen, blocks_per_mp);
 406                                 xlen -= len;
 407                                 bio_bytes += len << inode->i_blkbits;
 408                                 continue;
 409                         }
 410                         /* Not contiguous */
 411                         if (bio_add_page(bio, page, bio_bytes, bio_offset) <
 412                             bio_bytes)
 413                                 goto add_failed;
 414                         /*
 415                          * Increment counter before submitting i/o to keep
 416                          * count from hitting zero before we're through
 417                          */
 418                         inc_io(page);
 419                         if (!bio->bi_size)
 420                                 goto dump_bio;
 421                         submit_bio(WRITE, bio);
 422                         nr_underway++;
 423                         bio = NULL;
 424                 } else
 425                         inc_io(page);
 426                 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
 427                 pblock = metapage_get_blocks(inode, lblock, &xlen);
 428                 if (!pblock) {
 429                         printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
 430                         /*
 431                          * We already called inc_io(), but can't cancel it
 432                          * with dec_io() until we're done with the page
 433                          */
 434                         bad_blocks++;
 435                         continue;
 436                 }
 437                 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
 438
 439                 bio = bio_alloc(GFP_NOFS, 1);
 440                 bio->bi_bdev = inode->i_sb->s_bdev;
 441                 bio->bi_sector = pblock << (inode->i_blkbits - 9);
 442                 bio->bi_end_io = metapage_write_end_io;
 443                 bio->bi_private = page;
 444
 445                 /* Don't call bio_add_page yet, we may add to this vec */
 446                 bio_offset = offset;
 447                 bio_bytes = len << inode->i_blkbits;
 448
 449                 xlen -= len;
 450                 next_block = lblock + len;
 451         }
 452         if (bio) {
 453                 if (bio_add_page(bio, page, bio_bytes, bio_offset) < bio_bytes)
 454                                 goto add_failed;
 455                 if (!bio->bi_size)
 456                         goto dump_bio;
 457
 458                 submit_bio(WRITE, bio);
 459                 nr_underway++;
 460         }
 461         if (redirty)
 462                 redirty_page_for_writepage(wbc, page);
 463
 464         unlock_page(page);
 465
 466         if (bad_blocks)
 467                 goto err_out;
 468
 469         if (nr_underway == 0)
 470                 end_page_writeback(page);
 471
 472         return 0;
 473 add_failed:
 474         /* We should never reach here, since we're only adding one vec */
 475         printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
 476         goto skip;
 477 dump_bio:
 478         print_hex_dump(KERN_ERR, "JFS: dump of bio: ", DUMP_PREFIX_ADDRESS, 16,
 479                        4, bio, sizeof(*bio), 0);
 480 skip:
 481         bio_put(bio);
 482         unlock_page(page);
 483         dec_io(page, last_write_complete);
 484 err_out:
 485         while (bad_blocks--)
 486                 dec_io(page, last_write_complete);
 487         return -EIO;
 488 }
 489
 490 static int metapage_readpage(struct file *fp, struct page *page)
 491 {
 492         struct inode *inode = page->mapping->host;
 493         struct bio *bio = NULL;
 494         int block_offset;
 495         int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
 496         sector_t page_start;    /* address of page in fs blocks */
 497         sector_t pblock;
 498         int xlen;
 499         unsigned int len;
 500         int offset;
 501
 502         BUG_ON(!PageLocked(page));
 503         page_start = (sector_t)page->index <<
 504                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
 505
 506         block_offset = 0;
 507         while (block_offset < blocks_per_page) {
 508                 xlen = blocks_per_page - block_offset;
 509                 pblock = metapage_get_blocks(inode, page_start + block_offset,
 510                                              &xlen);
 511                 if (pblock) {
 512                         if (!PagePrivate(page))
 513                                 insert_metapage(page, NULL);
 514                         inc_io(page);
 515                         if (bio)
 516                                 submit_bio(READ, bio);
 517
 518                         bio = bio_alloc(GFP_NOFS, 1);
 519                         bio->bi_bdev = inode->i_sb->s_bdev;
 520                         bio->bi_sector = pblock << (inode->i_blkbits - 9);
 521                         bio->bi_end_io = metapage_read_end_io;
 522                         bio->bi_private = page;
 523                         len = xlen << inode->i_blkbits;
 524                         offset = block_offset << inode->i_blkbits;
 525                         if (bio_add_page(bio, page, len, offset) < len)
 526                                 goto add_failed;
 527                         block_offset += xlen;
 528                 } else
 529                         block_offset++;
 530         }
 531         if (bio)
 532                 submit_bio(READ, bio);
 533         else
 534                 unlock_page(page);
 535
 536         return 0;
 537
 538 add_failed:
 539         printk(KERN_ERR "JFS: bio_add_page failed unexpectedly\n");
 540         bio_put(bio);
 541         dec_io(page, last_read_complete);
 542         return -EIO;
 543 }
 544
 545 static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
 546 {
 547         struct metapage *mp;
 548         int ret = 1;
 549         int offset;
 550
 551         for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 552                 mp = page_to_mp(page, offset);
 553
 554                 if (!mp)
 555                         continue;
 556
 557                 jfs_info("metapage_releasepage: mp = 0x%p", mp);
 558                 if (mp->count || mp->nohomeok ||
 559                     test_bit(META_dirty, &mp->flag)) {
 560                         jfs_info("count = %ld, nohomeok = %d", mp->count,
 561                                  mp->nohomeok);
 562                         ret = 0;
 563                         continue;
 564                 }
 565                 if (mp->lsn)
 566                         remove_from_logsync(mp);
 567                 remove_metapage(page, mp);
 568                 INCREMENT(mpStat.pagefree);
 569                 free_metapage(mp);
 570         }
 571         return ret;
 572 }
 573
 574 static void metapage_invalidatepage(struct page *page, unsigned long offset)
 575 {
 576         BUG_ON(offset);
 577
 578         BUG_ON(PageWriteback(page));
 579
 580         metapage_releasepage(page, 0);
 581 }
 582
 583 const struct address_space_operations jfs_metapage_aops = {
 584         .readpage       = metapage_readpage,
 585         .writepage      = metapage_writepage,
 586         .sync_page      = block_sync_page,
 587         .releasepage    = metapage_releasepage,
 588         .invalidatepage = metapage_invalidatepage,
 589         .set_page_dirty = __set_page_dirty_nobuffers,
 590 };
 591
 592 struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 593                                 unsigned int size, int absolute,
 594                                 unsigned long new)
 595 {
 596         int l2BlocksPerPage;
 597         int l2bsize;
 598         struct address_space *mapping;
 599         struct metapage *mp = NULL;
 600         struct page *page;
 601         unsigned long page_index;
 602         unsigned long page_offset;
 603
 604         jfs_info("__get_metapage: ino = %ld, lblock = 0x%lx, abs=%d",
 605                  inode->i_ino, lblock, absolute);
 606
 607         l2bsize = inode->i_blkbits;
 608         l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
 609         page_index = lblock >> l2BlocksPerPage;
 610         page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
 611         if ((page_offset + size) > PAGE_CACHE_SIZE) {
 612                 jfs_err("MetaData crosses page boundary!!");
 613                 jfs_err("lblock = %lx, size  = %d", lblock, size);
 614                 dump_stack();
 615                 return NULL;
 616         }
 617         if (absolute)
 618                 mapping = JFS_SBI(inode->i_sb)->direct_inode->i_mapping;
 619         else {
 620                 /*
 621                  * If an nfs client tries to read an inode that is larger
 622                  * than any existing inodes, we may try to read past the
 623                  * end of the inode map
 624                  */
 625                 if ((lblock << inode->i_blkbits) >= inode->i_size)
 626                         return NULL;
 627                 mapping = inode->i_mapping;
 628         }
 629
 630         if (new && (PSIZE == PAGE_CACHE_SIZE)) {
 631                 page = grab_cache_page(mapping, page_index);
 632                 if (!page) {
 633                         jfs_err("grab_cache_page failed!");
 634                         return NULL;
 635                 }
 636                 SetPageUptodate(page);
 637         } else {
 638                 page = read_mapping_page(mapping, page_index, NULL);
 639                 if (IS_ERR(page) || !PageUptodate(page)) {
 640                         jfs_err("read_mapping_page failed!");
 641                         return NULL;
 642                 }
 643                 lock_page(page);
 644         }
 645
 646         mp = page_to_mp(page, page_offset);
 647         if (mp) {
 648                 if (mp->logical_size != size) {
 649                         jfs_error(inode->i_sb,
 650                                   "__get_metapage: mp->logical_size != size");
 651                         jfs_err("logical_size = %d, size = %d",
 652                                 mp->logical_size, size);
 653                         dump_stack();
 654                         goto unlock;
 655                 }
 656                 mp->count++;
 657                 lock_metapage(mp);
 658                 if (test_bit(META_discard, &mp->flag)) {
 659                         if (!new) {
 660                                 jfs_error(inode->i_sb,
 661                                           "__get_metapage: using a "
 662                                           "discarded metapage");
 663                                 discard_metapage(mp);
 664                                 goto unlock;
 665                         }
 666                         clear_bit(META_discard, &mp->flag);
 667                 }
 668         } else {
 669                 INCREMENT(mpStat.pagealloc);
 670                 mp = alloc_metapage(GFP_NOFS);
 671                 mp->page = page;
 672                 mp->flag = 0;
 673                 mp->xflag = COMMIT_PAGE;
 674                 mp->count = 1;
 675                 mp->nohomeok = 0;
 676                 mp->logical_size = size;
 677                 mp->data = page_address(page) + page_offset;
 678                 mp->index = lblock;
 679                 if (unlikely(insert_metapage(page, mp))) {
 680                         free_metapage(mp);
 681                         goto unlock;
 682                 }
 683                 lock_metapage(mp);
 684         }
 685
 686         if (new) {
 687                 jfs_info("zeroing mp = 0x%p", mp);
 688                 memset(mp->data, 0, PSIZE);
 689         }
 690
 691         unlock_page(page);
 692         jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
 693         return mp;
 694
 695 unlock:
 696         unlock_page(page);
 697         return NULL;
 698 }
 699
 700 void grab_metapage(struct metapage * mp)
 701 {
 702         jfs_info("grab_metapage: mp = 0x%p", mp);
 703         page_cache_get(mp->page);
 704         lock_page(mp->page);
 705         mp->count++;
 706         lock_metapage(mp);
 707         unlock_page(mp->page);
 708 }
 709
 710 void force_metapage(struct metapage *mp)
 711 {
 712         struct page *page = mp->page;
 713         jfs_info("force_metapage: mp = 0x%p", mp);
 714         set_bit(META_forcewrite, &mp->flag);
 715         clear_bit(META_sync, &mp->flag);
 716         page_cache_get(page);
 717         lock_page(page);
 718         set_page_dirty(page);
 719         write_one_page(page, 1);
 720         clear_bit(META_forcewrite, &mp->flag);
 721         page_cache_release(page);
 722 }
 723
 724 void hold_metapage(struct metapage *mp)
 725 {
 726         lock_page(mp->page);
 727 }
 728
 729 void put_metapage(struct metapage *mp)
 730 {
 731         if (mp->count || mp->nohomeok) {
 732                 /* Someone else will release this */
 733                 unlock_page(mp->page);
 734                 return;
 735         }
 736         page_cache_get(mp->page);
 737         mp->count++;
 738         lock_metapage(mp);
 739         unlock_page(mp->page);
 740         release_metapage(mp);
 741 }
 742
 743 void release_metapage(struct metapage * mp)
 744 {
 745         struct page *page = mp->page;
 746         jfs_info("release_metapage: mp = 0x%p, flag = 0x%lx", mp, mp->flag);
 747
 748         BUG_ON(!page);
 749
 750         lock_page(page);
 751         unlock_metapage(mp);
 752
 753         assert(mp->count);
 754         if (--mp->count || mp->nohomeok) {
 755                 unlock_page(page);
 756                 page_cache_release(page);
 757                 return;
 758         }
 759
 760         if (test_bit(META_dirty, &mp->flag)) {
 761                 set_page_dirty(page);
 762                 if (test_bit(META_sync, &mp->flag)) {
 763                         clear_bit(META_sync, &mp->flag);
 764                         write_one_page(page, 1);
 765                         lock_page(page); /* write_one_page unlocks the page */
 766                 }
 767         } else if (mp->lsn)     /* discard_metapage doesn't remove it */
 768                 remove_from_logsync(mp);
 769
 770         /* Try to keep metapages from using up too much memory */
 771         drop_metapage(page, mp);
 772
 773         unlock_page(page);
 774         page_cache_release(page);
 775 }
 776
 777 void __invalidate_metapages(struct inode *ip, s64 addr, int len)
 778 {
 779         sector_t lblock;
 780         int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
 781         int BlocksPerPage = 1 << l2BlocksPerPage;
 782         /* All callers are interested in block device's mapping */
 783         struct address_space *mapping =
 784                 JFS_SBI(ip->i_sb)->direct_inode->i_mapping;
 785         struct metapage *mp;
 786         struct page *page;
 787         unsigned int offset;
 788
 789         /*
 790          * Mark metapages to discard.  They will eventually be
 791          * released, but should not be written.
 792          */
 793         for (lblock = addr & ~(BlocksPerPage - 1); lblock < addr + len;
 794              lblock += BlocksPerPage) {
 795                 page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
 796                 if (!page)
 797                         continue;
 798                 for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
 799                         mp = page_to_mp(page, offset);
 800                         if (!mp)
 801                                 continue;
 802                         if (mp->index < addr)
 803                                 continue;
 804                         if (mp->index >= addr + len)
 805                                 break;
 806
 807                         clear_bit(META_dirty, &mp->flag);
 808                         set_bit(META_discard, &mp->flag);
 809                         if (mp->lsn)
 810                                 remove_from_logsync(mp);
 811                 }
 812                 unlock_page(page);
 813                 page_cache_release(page);
 814         }
 815 }
 816
 817 #ifdef CONFIG_JFS_STATISTICS
 818 static int jfs_mpstat_proc_show(struct seq_file *m, void *v)
 819 {
 820         seq_printf(m,
 821                        "JFS Metapage statistics\n"
 822                        "=======================\n"
 823                        "page allocations = %d\n"
 824                        "page frees = %d\n"
 825                        "lock waits = %d\n",
 826                        mpStat.pagealloc,
 827                        mpStat.pagefree,
 828                        mpStat.lockwait);
 829         return 0;
 830 }
 831
 832 static int jfs_mpstat_proc_open(struct inode *inode, struct file *file)
 833 {
 834         return single_open(file, jfs_mpstat_proc_show, NULL);
 835 }
 836
 837 const struct file_operations jfs_mpstat_proc_fops = {
 838         .owner          = THIS_MODULE,
 839         .open           = jfs_mpstat_proc_open,
 840         .read           = seq_read,
 841         .llseek         = seq_lseek,
 842         .release        = single_release,
 843 };
 844 #endif