git.oblomov.eu Git - linux-2.6/blob - fs/gfs2/ops_address.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License version 2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/pagevec.h>
  17 #include <linux/mpage.h>
  18 #include <linux/fs.h>
  19 #include <linux/gfs2_ondisk.h>
  20 #include <linux/lm_interface.h>
  21
  22 #include "gfs2.h"
  23 #include "incore.h"
  24 #include "bmap.h"
  25 #include "glock.h"
  26 #include "inode.h"
  27 #include "log.h"
  28 #include "meta_io.h"
  29 #include "ops_address.h"
  30 #include "quota.h"
  31 #include "trans.h"
  32 #include "rgrp.h"
  33 #include "ops_file.h"
  34 #include "util.h"
  35 #include "glops.h"
  36
  37
  38 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
  39                                    unsigned int from, unsigned int to)
  40 {
  41         struct buffer_head *head = page_buffers(page);
  42         unsigned int bsize = head->b_size;
  43         struct buffer_head *bh;
  44         unsigned int start, end;
  45
  46         for (bh = head, start = 0; bh != head || !start;
  47              bh = bh->b_this_page, start = end) {
  48                 end = start + bsize;
  49                 if (end <= from || start >= to)
  50                         continue;
  51                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
  52         }
  53 }
  54
  55 /**
  56  * gfs2_get_block - Fills in a buffer head with details about a block
  57  * @inode: The inode
  58  * @lblock: The block number to look up
  59  * @bh_result: The buffer head to return the result in
  60  * @create: Non-zero if we may add block to the file
  61  *
  62  * Returns: errno
  63  */
  64
  65 int gfs2_get_block(struct inode *inode, sector_t lblock,
  66                    struct buffer_head *bh_result, int create)
  67 {
  68         return gfs2_block_map(inode, lblock, create, bh_result);
  69 }
  70
  71 /**
  72  * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
  73  * @inode: The inode
  74  * @lblock: The block number to look up
  75  * @bh_result: The buffer head to return the result in
  76  * @create: Non-zero if we may add block to the file
  77  *
  78  * Returns: errno
  79  */
  80
  81 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
  82                                   struct buffer_head *bh_result, int create)
  83 {
  84         int error;
  85
  86         error = gfs2_block_map(inode, lblock, 0, bh_result);
  87         if (error)
  88                 return error;
  89         if (bh_result->b_blocknr == 0)
  90                 return -EIO;
  91         return 0;
  92 }
  93
  94 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
  95                                  struct buffer_head *bh_result, int create)
  96 {
  97         return gfs2_block_map(inode, lblock, 0, bh_result);
  98 }
  99
 100 /**
 101  * gfs2_writepage - Write complete page
 102  * @page: Page to write
 103  *
 104  * Returns: errno
 105  *
 106  * Some of this is copied from block_write_full_page() although we still
 107  * call it to do most of the work.
 108  */
 109
 110 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 111 {
 112         struct inode *inode = page->mapping->host;
 113         struct gfs2_inode *ip = GFS2_I(inode);
 114         struct gfs2_sbd *sdp = GFS2_SB(inode);
 115         loff_t i_size = i_size_read(inode);
 116         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 117         unsigned offset;
 118         int error;
 119         int done_trans = 0;
 120
 121         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 122                 unlock_page(page);
 123                 return -EIO;
 124         }
 125         if (current->journal_info)
 126                 goto out_ignore;
 127
 128         /* Is the page fully outside i_size? (truncate in progress) */
 129         offset = i_size & (PAGE_CACHE_SIZE-1);
 130         if (page->index > end_index || (page->index == end_index && !offset)) {
 131                 page->mapping->a_ops->invalidatepage(page, 0);
 132                 unlock_page(page);
 133                 return 0; /* don't care */
 134         }
 135
 136         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 137                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 138                 if (error)
 139                         goto out_ignore;
 140                 if (!page_has_buffers(page)) {
 141                         create_empty_buffers(page, inode->i_sb->s_blocksize,
 142                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
 143                 }
 144                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 145                 done_trans = 1;
 146         }
 147         error = block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 148         if (done_trans)
 149                 gfs2_trans_end(sdp);
 150         gfs2_meta_cache_flush(ip);
 151         return error;
 152
 153 out_ignore:
 154         redirty_page_for_writepage(wbc, page);
 155         unlock_page(page);
 156         return 0;
 157 }
 158
 159 /**
 160  * stuffed_readpage - Fill in a Linux page with stuffed file data
 161  * @ip: the inode
 162  * @page: the page
 163  *
 164  * Returns: errno
 165  */
 166
 167 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 168 {
 169         struct buffer_head *dibh;
 170         void *kaddr;
 171         int error;
 172
 173         BUG_ON(page->index);
 174
 175         error = gfs2_meta_inode_buffer(ip, &dibh);
 176         if (error)
 177                 return error;
 178
 179         kaddr = kmap_atomic(page, KM_USER0);
 180         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 181                ip->i_di.di_size);
 182         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 183         kunmap_atomic(kaddr, KM_USER0);
 184
 185         brelse(dibh);
 186
 187         SetPageUptodate(page);
 188
 189         return 0;
 190 }
 191
 192
 193 /**
 194  * gfs2_readpage - readpage with locking
 195  * @file: The file to read a page for. N.B. This may be NULL if we are
 196  * reading an internal file.
 197  * @page: The page to read
 198  *
 199  * Returns: errno
 200  */
 201
 202 static int gfs2_readpage(struct file *file, struct page *page)
 203 {
 204         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 205         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 206         struct gfs2_file *gf = NULL;
 207         struct gfs2_holder gh;
 208         int error;
 209         int do_unlock = 0;
 210
 211         if (likely(file != &gfs2_internal_file_sentinel)) {
 212                 if (file) {
 213                         gf = file->private_data;
 214                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 215                                 /* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */
 216                                 goto skip_lock;
 217                 }
 218                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
 219                 do_unlock = 1;
 220                 error = gfs2_glock_nq_m_atime(1, &gh);
 221                 if (unlikely(error))
 222                         goto out_unlock;
 223         }
 224
 225 skip_lock:
 226         if (gfs2_is_stuffed(ip)) {
 227                 error = stuffed_readpage(ip, page);
 228                 unlock_page(page);
 229         } else
 230                 error = mpage_readpage(page, gfs2_get_block);
 231
 232         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 233                 error = -EIO;
 234
 235         if (do_unlock) {
 236                 gfs2_glock_dq_m(1, &gh);
 237                 gfs2_holder_uninit(&gh);
 238         }
 239 out:
 240         return error;
 241 out_unlock:
 242         if (error == GLR_TRYFAILED)
 243                 error = AOP_TRUNCATED_PAGE;
 244         unlock_page(page);
 245         if (do_unlock)
 246                 gfs2_holder_uninit(&gh);
 247         goto out;
 248 }
 249
 250 /**
 251  * gfs2_readpages - Read a bunch of pages at once
 252  *
 253  * Some notes:
 254  * 1. This is only for readahead, so we can simply ignore any things
 255  *    which are slightly inconvenient (such as locking conflicts between
 256  *    the page lock and the glock) and return having done no I/O. Its
 257  *    obviously not something we'd want to do on too regular a basis.
 258  *    Any I/O we ignore at this time will be done via readpage later.
 259  * 2. We have to handle stuffed files here too.
 260  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 261  * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
 262  * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
 263  *    well as read-ahead.
 264  */
 265 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 266                           struct list_head *pages, unsigned nr_pages)
 267 {
 268         struct inode *inode = mapping->host;
 269         struct gfs2_inode *ip = GFS2_I(inode);
 270         struct gfs2_sbd *sdp = GFS2_SB(inode);
 271         struct gfs2_holder gh;
 272         unsigned page_idx;
 273         int ret;
 274         int do_unlock = 0;
 275
 276         if (likely(file != &gfs2_internal_file_sentinel)) {
 277                 if (file) {
 278                         struct gfs2_file *gf = file->private_data;
 279                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 280                                 goto skip_lock;
 281                 }
 282                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 283                                  LM_FLAG_TRY_1CB|GL_ATIME, &gh);
 284                 do_unlock = 1;
 285                 ret = gfs2_glock_nq_m_atime(1, &gh);
 286                 if (ret == GLR_TRYFAILED)
 287                         goto out_noerror;
 288                 if (unlikely(ret))
 289                         goto out_unlock;
 290         }
 291 skip_lock:
 292         if (gfs2_is_stuffed(ip)) {
 293                 struct pagevec lru_pvec;
 294                 pagevec_init(&lru_pvec, 0);
 295                 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 296                         struct page *page = list_entry(pages->prev, struct page, lru);
 297                         prefetchw(&page->flags);
 298                         list_del(&page->lru);
 299                         if (!add_to_page_cache(page, mapping,
 300                                                page->index, GFP_KERNEL)) {
 301                                 ret = stuffed_readpage(ip, page);
 302                                 unlock_page(page);
 303                                 if (!pagevec_add(&lru_pvec, page))
 304                                          __pagevec_lru_add(&lru_pvec);
 305                         } else {
 306                                 page_cache_release(page);
 307                         }
 308                 }
 309                 pagevec_lru_add(&lru_pvec);
 310                 ret = 0;
 311         } else {
 312                 /* What we really want to do .... */
 313                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 314         }
 315
 316         if (do_unlock) {
 317                 gfs2_glock_dq_m(1, &gh);
 318                 gfs2_holder_uninit(&gh);
 319         }
 320 out:
 321         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 322                 ret = -EIO;
 323         return ret;
 324 out_noerror:
 325         ret = 0;
 326 out_unlock:
 327         if (do_unlock)
 328                 gfs2_holder_uninit(&gh);
 329         goto out;
 330 }
 331
 332 /**
 333  * gfs2_prepare_write - Prepare to write a page to a file
 334  * @file: The file to write to
 335  * @page: The page which is to be prepared for writing
 336  * @from: From (byte range within page)
 337  * @to: To (byte range within page)
 338  *
 339  * Returns: errno
 340  */
 341
 342 static int gfs2_prepare_write(struct file *file, struct page *page,
 343                               unsigned from, unsigned to)
 344 {
 345         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 346         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 347         unsigned int data_blocks, ind_blocks, rblocks;
 348         int alloc_required;
 349         int error = 0;
 350         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 351         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 352         struct gfs2_alloc *al;
 353         unsigned int write_len = to - from;
 354
 355
 356         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
 357         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 358         if (unlikely(error)) {
 359                 if (error == GLR_TRYFAILED)
 360                         error = AOP_TRUNCATED_PAGE;
 361                 goto out_uninit;
 362         }
 363
 364         gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
 365
 366         error = gfs2_write_alloc_required(ip, pos, write_len, &alloc_required);
 367         if (error)
 368                 goto out_unlock;
 369
 370
 371         ip->i_alloc.al_requested = 0;
 372         if (alloc_required) {
 373                 al = gfs2_alloc_get(ip);
 374
 375                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 376                 if (error)
 377                         goto out_alloc_put;
 378
 379                 error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
 380                 if (error)
 381                         goto out_qunlock;
 382
 383                 al->al_requested = data_blocks + ind_blocks;
 384                 error = gfs2_inplace_reserve(ip);
 385                 if (error)
 386                         goto out_qunlock;
 387         }
 388
 389         rblocks = RES_DINODE + ind_blocks;
 390         if (gfs2_is_jdata(ip))
 391                 rblocks += data_blocks ? data_blocks : 1;
 392         if (ind_blocks || data_blocks)
 393                 rblocks += RES_STATFS + RES_QUOTA;
 394
 395         error = gfs2_trans_begin(sdp, rblocks, 0);
 396         if (error)
 397                 goto out;
 398
 399         if (gfs2_is_stuffed(ip)) {
 400                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 401                         error = gfs2_unstuff_dinode(ip, page);
 402                         if (error == 0)
 403                                 goto prepare_write;
 404                 } else if (!PageUptodate(page))
 405                         error = stuffed_readpage(ip, page);
 406                 goto out;
 407         }
 408
 409 prepare_write:
 410         error = block_prepare_write(page, from, to, gfs2_get_block);
 411
 412 out:
 413         if (error) {
 414                 gfs2_trans_end(sdp);
 415                 if (alloc_required) {
 416                         gfs2_inplace_release(ip);
 417 out_qunlock:
 418                         gfs2_quota_unlock(ip);
 419 out_alloc_put:
 420                         gfs2_alloc_put(ip);
 421                 }
 422 out_unlock:
 423                 gfs2_glock_dq_m(1, &ip->i_gh);
 424 out_uninit:
 425                 gfs2_holder_uninit(&ip->i_gh);
 426         }
 427
 428         return error;
 429 }
 430
 431 /**
 432  * gfs2_commit_write - Commit write to a file
 433  * @file: The file to write to
 434  * @page: The page containing the data
 435  * @from: From (byte range within page)
 436  * @to: To (byte range within page)
 437  *
 438  * Returns: errno
 439  */
 440
 441 static int gfs2_commit_write(struct file *file, struct page *page,
 442                              unsigned from, unsigned to)
 443 {
 444         struct inode *inode = page->mapping->host;
 445         struct gfs2_inode *ip = GFS2_I(inode);
 446         struct gfs2_sbd *sdp = GFS2_SB(inode);
 447         int error = -EOPNOTSUPP;
 448         struct buffer_head *dibh;
 449         struct gfs2_alloc *al = &ip->i_alloc;
 450         struct gfs2_dinode *di;
 451
 452         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 453                 goto fail_nounlock;
 454
 455         error = gfs2_meta_inode_buffer(ip, &dibh);
 456         if (error)
 457                 goto fail_endtrans;
 458
 459         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 460         di = (struct gfs2_dinode *)dibh->b_data;
 461
 462         if (gfs2_is_stuffed(ip)) {
 463                 u64 file_size;
 464                 void *kaddr;
 465
 466                 file_size = ((u64)page->index << PAGE_CACHE_SHIFT) + to;
 467
 468                 kaddr = kmap_atomic(page, KM_USER0);
 469                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 470                        kaddr + from, to - from);
 471                 kunmap_atomic(kaddr, KM_USER0);
 472
 473                 SetPageUptodate(page);
 474
 475                 if (inode->i_size < file_size)
 476                         i_size_write(inode, file_size);
 477         } else {
 478                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 479                     gfs2_is_jdata(ip))
 480                         gfs2_page_add_databufs(ip, page, from, to);
 481                 error = generic_commit_write(file, page, from, to);
 482                 if (error)
 483                         goto fail;
 484         }
 485
 486         if (ip->i_di.di_size < inode->i_size) {
 487                 ip->i_di.di_size = inode->i_size;
 488                 di->di_size = cpu_to_be64(inode->i_size);
 489         }
 490
 491         brelse(dibh);
 492         gfs2_trans_end(sdp);
 493         if (al->al_requested) {
 494                 gfs2_inplace_release(ip);
 495                 gfs2_quota_unlock(ip);
 496                 gfs2_alloc_put(ip);
 497         }
 498         gfs2_glock_dq_m(1, &ip->i_gh);
 499         gfs2_holder_uninit(&ip->i_gh);
 500         return 0;
 501
 502 fail:
 503         brelse(dibh);
 504 fail_endtrans:
 505         gfs2_trans_end(sdp);
 506         if (al->al_requested) {
 507                 gfs2_inplace_release(ip);
 508                 gfs2_quota_unlock(ip);
 509                 gfs2_alloc_put(ip);
 510         }
 511         gfs2_glock_dq_m(1, &ip->i_gh);
 512         gfs2_holder_uninit(&ip->i_gh);
 513 fail_nounlock:
 514         ClearPageUptodate(page);
 515         return error;
 516 }
 517
 518 /**
 519  * gfs2_bmap - Block map function
 520  * @mapping: Address space info
 521  * @lblock: The block to map
 522  *
 523  * Returns: The disk address for the block or 0 on hole or error
 524  */
 525
 526 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 527 {
 528         struct gfs2_inode *ip = GFS2_I(mapping->host);
 529         struct gfs2_holder i_gh;
 530         sector_t dblock = 0;
 531         int error;
 532
 533         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 534         if (error)
 535                 return 0;
 536
 537         if (!gfs2_is_stuffed(ip))
 538                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 539
 540         gfs2_glock_dq_uninit(&i_gh);
 541
 542         return dblock;
 543 }
 544
 545 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 546 {
 547         struct gfs2_bufdata *bd;
 548
 549         gfs2_log_lock(sdp);
 550         bd = bh->b_private;
 551         if (bd) {
 552                 bd->bd_bh = NULL;
 553                 bh->b_private = NULL;
 554         }
 555         gfs2_log_unlock(sdp);
 556
 557         lock_buffer(bh);
 558         clear_buffer_dirty(bh);
 559         bh->b_bdev = NULL;
 560         clear_buffer_mapped(bh);
 561         clear_buffer_req(bh);
 562         clear_buffer_new(bh);
 563         clear_buffer_delay(bh);
 564         unlock_buffer(bh);
 565 }
 566
 567 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 568 {
 569         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 570         struct buffer_head *head, *bh, *next;
 571         unsigned int curr_off = 0;
 572
 573         BUG_ON(!PageLocked(page));
 574         if (!page_has_buffers(page))
 575                 return;
 576
 577         bh = head = page_buffers(page);
 578         do {
 579                 unsigned int next_off = curr_off + bh->b_size;
 580                 next = bh->b_this_page;
 581
 582                 if (offset <= curr_off)
 583                         discard_buffer(sdp, bh);
 584
 585                 curr_off = next_off;
 586                 bh = next;
 587         } while (bh != head);
 588
 589         if (!offset)
 590                 try_to_release_page(page, 0);
 591
 592         return;
 593 }
 594
 595 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 596                               const struct iovec *iov, loff_t offset,
 597                               unsigned long nr_segs)
 598 {
 599         struct file *file = iocb->ki_filp;
 600         struct inode *inode = file->f_mapping->host;
 601         struct gfs2_inode *ip = GFS2_I(inode);
 602         struct gfs2_holder gh;
 603         int rv;
 604
 605         if (rw == READ)
 606                 mutex_lock(&inode->i_mutex);
 607         /*
 608          * Shared lock, even if its a write, since we do no allocation
 609          * on this path. All we need change is atime.
 610          */
 611         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 612         rv = gfs2_glock_nq_m_atime(1, &gh);
 613         if (rv)
 614                 goto out;
 615
 616         if (offset > i_size_read(inode))
 617                 goto out;
 618
 619         /*
 620          * Should we return an error here? I can't see that O_DIRECT for
 621          * a journaled file makes any sense. For now we'll silently fall
 622          * back to buffered I/O, likewise we do the same for stuffed
 623          * files since they are (a) small and (b) unaligned.
 624          */
 625         if (gfs2_is_jdata(ip))
 626                 goto out;
 627
 628         if (gfs2_is_stuffed(ip))
 629                 goto out;
 630
 631         rv = blockdev_direct_IO_own_locking(rw, iocb, inode,
 632                                             inode->i_sb->s_bdev,
 633                                             iov, offset, nr_segs,
 634                                             gfs2_get_block_direct, NULL);
 635 out:
 636         gfs2_glock_dq_m(1, &gh);
 637         gfs2_holder_uninit(&gh);
 638         if (rw == READ)
 639                 mutex_unlock(&inode->i_mutex);
 640
 641         return rv;
 642 }
 643
 644 /**
 645  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
 646  * @bh: the buffer we're stuck on
 647  *
 648  */
 649
 650 static void stuck_releasepage(struct buffer_head *bh)
 651 {
 652         struct inode *inode = bh->b_page->mapping->host;
 653         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 654         struct gfs2_bufdata *bd = bh->b_private;
 655         struct gfs2_glock *gl;
 656 static unsigned limit = 0;
 657
 658         if (limit > 3)
 659                 return;
 660         limit++;
 661
 662         fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
 663         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
 664                 (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
 665         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
 666         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
 667
 668         if (!bd)
 669                 return;
 670
 671         gl = bd->bd_gl;
 672
 673         fs_warn(sdp, "gl = (%u, %llu)\n",
 674                 gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 675
 676         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
 677                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
 678                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 679
 680         if (gl->gl_ops == &gfs2_inode_glops) {
 681                 struct gfs2_inode *ip = gl->gl_object;
 682                 unsigned int x;
 683
 684                 if (!ip)
 685                         return;
 686
 687                 fs_warn(sdp, "ip = %llu %llu\n",
 688                         (unsigned long long)ip->i_num.no_formal_ino,
 689                         (unsigned long long)ip->i_num.no_addr);
 690
 691                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 692                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
 693                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
 694         }
 695 }
 696
 697 /**
 698  * gfs2_releasepage - free the metadata associated with a page
 699  * @page: the page that's being released
 700  * @gfp_mask: passed from Linux VFS, ignored by us
 701  *
 702  * Call try_to_free_buffers() if the buffers in this page can be
 703  * released.
 704  *
 705  * Returns: 0
 706  */
 707
 708 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 709 {
 710         struct inode *aspace = page->mapping->host;
 711         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
 712         struct buffer_head *bh, *head;
 713         struct gfs2_bufdata *bd;
 714         unsigned long t = jiffies + gfs2_tune_get(sdp, gt_stall_secs) * HZ;
 715
 716         if (!page_has_buffers(page))
 717                 goto out;
 718
 719         head = bh = page_buffers(page);
 720         do {
 721                 while (atomic_read(&bh->b_count)) {
 722                         if (!atomic_read(&aspace->i_writecount))
 723                                 return 0;
 724
 725                         if (!(gfp_mask & __GFP_WAIT))
 726                                 return 0;
 727
 728                         if (time_after_eq(jiffies, t)) {
 729                                 stuck_releasepage(bh);
 730                                 /* should we withdraw here? */
 731                                 return 0;
 732                         }
 733
 734                         yield();
 735                 }
 736
 737                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 738                 gfs2_assert_warn(sdp, !buffer_dirty(bh));
 739
 740                 gfs2_log_lock(sdp);
 741                 bd = bh->b_private;
 742                 if (bd) {
 743                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 744                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
 745                         gfs2_assert_warn(sdp, !bd->bd_ail);
 746                         bd->bd_bh = NULL;
 747                         if (!list_empty(&bd->bd_le.le_list))
 748                                 bd = NULL;
 749                         bh->b_private = NULL;
 750                 }
 751                 gfs2_log_unlock(sdp);
 752                 if (bd)
 753                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 754
 755                 bh = bh->b_this_page;
 756         } while (bh != head);
 757
 758 out:
 759         return try_to_free_buffers(page);
 760 }
 761
 762 const struct address_space_operations gfs2_file_aops = {
 763         .writepage = gfs2_writepage,
 764         .readpage = gfs2_readpage,
 765         .readpages = gfs2_readpages,
 766         .sync_page = block_sync_page,
 767         .prepare_write = gfs2_prepare_write,
 768         .commit_write = gfs2_commit_write,
 769         .bmap = gfs2_bmap,
 770         .invalidatepage = gfs2_invalidatepage,
 771         .releasepage = gfs2_releasepage,
 772         .direct_IO = gfs2_direct_IO,
 773 };
 774