SAFE public projects git trees. - safe/jmp/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_atime(&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 don't handle stuffed files here we let readpage do the honours.
 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         int ret = 0;
 273         int do_unlock = 0;
 274
 275         if (likely(file != &gfs2_internal_file_sentinel)) {
 276                 if (file) {
 277                         struct gfs2_file *gf = file->private_data;
 278                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 279                                 goto skip_lock;
 280                 }
 281                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 282                                  LM_FLAG_TRY_1CB|GL_ATIME, &gh);
 283                 do_unlock = 1;
 284                 ret = gfs2_glock_nq_atime(&gh);
 285                 if (ret == GLR_TRYFAILED)
 286                         goto out_noerror;
 287                 if (unlikely(ret))
 288                         goto out_unlock;
 289         }
 290 skip_lock:
 291         if (!gfs2_is_stuffed(ip))
 292                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 293
 294         if (do_unlock) {
 295                 gfs2_glock_dq_m(1, &gh);
 296                 gfs2_holder_uninit(&gh);
 297         }
 298 out:
 299         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 300                 ret = -EIO;
 301         return ret;
 302 out_noerror:
 303         ret = 0;
 304 out_unlock:
 305         if (do_unlock)
 306                 gfs2_holder_uninit(&gh);
 307         goto out;
 308 }
 309
 310 /**
 311  * gfs2_prepare_write - Prepare to write a page to a file
 312  * @file: The file to write to
 313  * @page: The page which is to be prepared for writing
 314  * @from: From (byte range within page)
 315  * @to: To (byte range within page)
 316  *
 317  * Returns: errno
 318  */
 319
 320 static int gfs2_prepare_write(struct file *file, struct page *page,
 321                               unsigned from, unsigned to)
 322 {
 323         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 324         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 325         unsigned int data_blocks, ind_blocks, rblocks;
 326         int alloc_required;
 327         int error = 0;
 328         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 329         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 330         struct gfs2_alloc *al;
 331         unsigned int write_len = to - from;
 332
 333
 334         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
 335         error = gfs2_glock_nq_atime(&ip->i_gh);
 336         if (unlikely(error)) {
 337                 if (error == GLR_TRYFAILED)
 338                         error = AOP_TRUNCATED_PAGE;
 339                 goto out_uninit;
 340         }
 341
 342         gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
 343
 344         error = gfs2_write_alloc_required(ip, pos, write_len, &alloc_required);
 345         if (error)
 346                 goto out_unlock;
 347
 348
 349         ip->i_alloc.al_requested = 0;
 350         if (alloc_required) {
 351                 al = gfs2_alloc_get(ip);
 352
 353                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 354                 if (error)
 355                         goto out_alloc_put;
 356
 357                 error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
 358                 if (error)
 359                         goto out_qunlock;
 360
 361                 al->al_requested = data_blocks + ind_blocks;
 362                 error = gfs2_inplace_reserve(ip);
 363                 if (error)
 364                         goto out_qunlock;
 365         }
 366
 367         rblocks = RES_DINODE + ind_blocks;
 368         if (gfs2_is_jdata(ip))
 369                 rblocks += data_blocks ? data_blocks : 1;
 370         if (ind_blocks || data_blocks)
 371                 rblocks += RES_STATFS + RES_QUOTA;
 372
 373         error = gfs2_trans_begin(sdp, rblocks, 0);
 374         if (error)
 375                 goto out;
 376
 377         if (gfs2_is_stuffed(ip)) {
 378                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 379                         error = gfs2_unstuff_dinode(ip, page);
 380                         if (error == 0)
 381                                 goto prepare_write;
 382                 } else if (!PageUptodate(page))
 383                         error = stuffed_readpage(ip, page);
 384                 goto out;
 385         }
 386
 387 prepare_write:
 388         error = block_prepare_write(page, from, to, gfs2_get_block);
 389
 390 out:
 391         if (error) {
 392                 gfs2_trans_end(sdp);
 393                 if (alloc_required) {
 394                         gfs2_inplace_release(ip);
 395 out_qunlock:
 396                         gfs2_quota_unlock(ip);
 397 out_alloc_put:
 398                         gfs2_alloc_put(ip);
 399                 }
 400 out_unlock:
 401                 gfs2_glock_dq_m(1, &ip->i_gh);
 402 out_uninit:
 403                 gfs2_holder_uninit(&ip->i_gh);
 404         }
 405
 406         return error;
 407 }
 408
 409 /**
 410  * gfs2_commit_write - Commit write to a file
 411  * @file: The file to write to
 412  * @page: The page containing the data
 413  * @from: From (byte range within page)
 414  * @to: To (byte range within page)
 415  *
 416  * Returns: errno
 417  */
 418
 419 static int gfs2_commit_write(struct file *file, struct page *page,
 420                              unsigned from, unsigned to)
 421 {
 422         struct inode *inode = page->mapping->host;
 423         struct gfs2_inode *ip = GFS2_I(inode);
 424         struct gfs2_sbd *sdp = GFS2_SB(inode);
 425         int error = -EOPNOTSUPP;
 426         struct buffer_head *dibh;
 427         struct gfs2_alloc *al = &ip->i_alloc;
 428         struct gfs2_dinode *di;
 429
 430         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 431                 goto fail_nounlock;
 432
 433         error = gfs2_meta_inode_buffer(ip, &dibh);
 434         if (error)
 435                 goto fail_endtrans;
 436
 437         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 438         di = (struct gfs2_dinode *)dibh->b_data;
 439
 440         if (gfs2_is_stuffed(ip)) {
 441                 u64 file_size;
 442                 void *kaddr;
 443
 444                 file_size = ((u64)page->index << PAGE_CACHE_SHIFT) + to;
 445
 446                 kaddr = kmap_atomic(page, KM_USER0);
 447                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 448                        kaddr + from, to - from);
 449                 kunmap_atomic(kaddr, KM_USER0);
 450
 451                 SetPageUptodate(page);
 452
 453                 if (inode->i_size < file_size) {
 454                         i_size_write(inode, file_size);
 455                         mark_inode_dirty(inode);
 456                 }
 457         } else {
 458                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 459                     gfs2_is_jdata(ip))
 460                         gfs2_page_add_databufs(ip, page, from, to);
 461                 error = generic_commit_write(file, page, from, to);
 462                 if (error)
 463                         goto fail;
 464         }
 465
 466         if (ip->i_di.di_size < inode->i_size) {
 467                 ip->i_di.di_size = inode->i_size;
 468                 di->di_size = cpu_to_be64(inode->i_size);
 469         }
 470
 471         brelse(dibh);
 472         gfs2_trans_end(sdp);
 473         if (al->al_requested) {
 474                 gfs2_inplace_release(ip);
 475                 gfs2_quota_unlock(ip);
 476                 gfs2_alloc_put(ip);
 477         }
 478         gfs2_glock_dq_m(1, &ip->i_gh);
 479         gfs2_holder_uninit(&ip->i_gh);
 480         return 0;
 481
 482 fail:
 483         brelse(dibh);
 484 fail_endtrans:
 485         gfs2_trans_end(sdp);
 486         if (al->al_requested) {
 487                 gfs2_inplace_release(ip);
 488                 gfs2_quota_unlock(ip);
 489                 gfs2_alloc_put(ip);
 490         }
 491         gfs2_glock_dq_m(1, &ip->i_gh);
 492         gfs2_holder_uninit(&ip->i_gh);
 493 fail_nounlock:
 494         ClearPageUptodate(page);
 495         return error;
 496 }
 497
 498 /**
 499  * gfs2_bmap - Block map function
 500  * @mapping: Address space info
 501  * @lblock: The block to map
 502  *
 503  * Returns: The disk address for the block or 0 on hole or error
 504  */
 505
 506 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 507 {
 508         struct gfs2_inode *ip = GFS2_I(mapping->host);
 509         struct gfs2_holder i_gh;
 510         sector_t dblock = 0;
 511         int error;
 512
 513         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 514         if (error)
 515                 return 0;
 516
 517         if (!gfs2_is_stuffed(ip))
 518                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 519
 520         gfs2_glock_dq_uninit(&i_gh);
 521
 522         return dblock;
 523 }
 524
 525 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 526 {
 527         struct gfs2_bufdata *bd;
 528
 529         gfs2_log_lock(sdp);
 530         bd = bh->b_private;
 531         if (bd) {
 532                 bd->bd_bh = NULL;
 533                 bh->b_private = NULL;
 534         }
 535         gfs2_log_unlock(sdp);
 536
 537         lock_buffer(bh);
 538         clear_buffer_dirty(bh);
 539         bh->b_bdev = NULL;
 540         clear_buffer_mapped(bh);
 541         clear_buffer_req(bh);
 542         clear_buffer_new(bh);
 543         clear_buffer_delay(bh);
 544         unlock_buffer(bh);
 545 }
 546
 547 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 548 {
 549         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 550         struct buffer_head *head, *bh, *next;
 551         unsigned int curr_off = 0;
 552
 553         BUG_ON(!PageLocked(page));
 554         if (!page_has_buffers(page))
 555                 return;
 556
 557         bh = head = page_buffers(page);
 558         do {
 559                 unsigned int next_off = curr_off + bh->b_size;
 560                 next = bh->b_this_page;
 561
 562                 if (offset <= curr_off)
 563                         discard_buffer(sdp, bh);
 564
 565                 curr_off = next_off;
 566                 bh = next;
 567         } while (bh != head);
 568
 569         if (!offset)
 570                 try_to_release_page(page, 0);
 571
 572         return;
 573 }
 574
 575 /**
 576  * gfs2_ok_for_dio - check that dio is valid on this file
 577  * @ip: The inode
 578  * @rw: READ or WRITE
 579  * @offset: The offset at which we are reading or writing
 580  *
 581  * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
 582  *          1 (to accept the i/o request)
 583  */
 584 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
 585 {
 586         /*
 587          * Should we return an error here? I can't see that O_DIRECT for
 588          * a journaled file makes any sense. For now we'll silently fall
 589          * back to buffered I/O, likewise we do the same for stuffed
 590          * files since they are (a) small and (b) unaligned.
 591          */
 592         if (gfs2_is_jdata(ip))
 593                 return 0;
 594
 595         if (gfs2_is_stuffed(ip))
 596                 return 0;
 597
 598         if (offset > i_size_read(&ip->i_inode))
 599                 return 0;
 600         return 1;
 601 }
 602
 603
 604
 605 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 606                               const struct iovec *iov, loff_t offset,
 607                               unsigned long nr_segs)
 608 {
 609         struct file *file = iocb->ki_filp;
 610         struct inode *inode = file->f_mapping->host;
 611         struct gfs2_inode *ip = GFS2_I(inode);
 612         struct gfs2_holder gh;
 613         int rv;
 614
 615         /*
 616          * Deferred lock, even if its a write, since we do no allocation
 617          * on this path. All we need change is atime, and this lock mode
 618          * ensures that other nodes have flushed their buffered read caches
 619          * (i.e. their page cache entries for this inode). We do not,
 620          * unfortunately have the option of only flushing a range like
 621          * the VFS does.
 622          */
 623         gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, GL_ATIME, &gh);
 624         rv = gfs2_glock_nq_atime(&gh);
 625         if (rv)
 626                 return rv;
 627         rv = gfs2_ok_for_dio(ip, rw, offset);
 628         if (rv != 1)
 629                 goto out; /* dio not valid, fall back to buffered i/o */
 630
 631         rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
 632                                            iov, offset, nr_segs,
 633                                            gfs2_get_block_direct, NULL);
 634 out:
 635         gfs2_glock_dq_m(1, &gh);
 636         gfs2_holder_uninit(&gh);
 637         return rv;
 638 }
 639
 640 /**
 641  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
 642  * @bh: the buffer we're stuck on
 643  *
 644  */
 645
 646 static void stuck_releasepage(struct buffer_head *bh)
 647 {
 648         struct inode *inode = bh->b_page->mapping->host;
 649         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 650         struct gfs2_bufdata *bd = bh->b_private;
 651         struct gfs2_glock *gl;
 652 static unsigned limit = 0;
 653
 654         if (limit > 3)
 655                 return;
 656         limit++;
 657
 658         fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
 659         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
 660                 (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
 661         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
 662         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
 663
 664         if (!bd)
 665                 return;
 666
 667         gl = bd->bd_gl;
 668
 669         fs_warn(sdp, "gl = (%u, %llu)\n",
 670                 gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 671
 672         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
 673                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
 674                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 675
 676         if (gl->gl_ops == &gfs2_inode_glops) {
 677                 struct gfs2_inode *ip = gl->gl_object;
 678                 unsigned int x;
 679
 680                 if (!ip)
 681                         return;
 682
 683                 fs_warn(sdp, "ip = %llu %llu\n",
 684                         (unsigned long long)ip->i_num.no_formal_ino,
 685                         (unsigned long long)ip->i_num.no_addr);
 686
 687                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 688                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
 689                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
 690         }
 691 }
 692
 693 /**
 694  * gfs2_releasepage - free the metadata associated with a page
 695  * @page: the page that's being released
 696  * @gfp_mask: passed from Linux VFS, ignored by us
 697  *
 698  * Call try_to_free_buffers() if the buffers in this page can be
 699  * released.
 700  *
 701  * Returns: 0
 702  */
 703
 704 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 705 {
 706         struct inode *aspace = page->mapping->host;
 707         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
 708         struct buffer_head *bh, *head;
 709         struct gfs2_bufdata *bd;
 710         unsigned long t = jiffies + gfs2_tune_get(sdp, gt_stall_secs) * HZ;
 711
 712         if (!page_has_buffers(page))
 713                 goto out;
 714
 715         head = bh = page_buffers(page);
 716         do {
 717                 while (atomic_read(&bh->b_count)) {
 718                         if (!atomic_read(&aspace->i_writecount))
 719                                 return 0;
 720
 721                         if (!(gfp_mask & __GFP_WAIT))
 722                                 return 0;
 723
 724                         if (time_after_eq(jiffies, t)) {
 725                                 stuck_releasepage(bh);
 726                                 /* should we withdraw here? */
 727                                 return 0;
 728                         }
 729
 730                         yield();
 731                 }
 732
 733                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 734                 gfs2_assert_warn(sdp, !buffer_dirty(bh));
 735
 736                 gfs2_log_lock(sdp);
 737                 bd = bh->b_private;
 738                 if (bd) {
 739                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 740                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
 741                         gfs2_assert_warn(sdp, !bd->bd_ail);
 742                         bd->bd_bh = NULL;
 743                         if (!list_empty(&bd->bd_le.le_list))
 744                                 bd = NULL;
 745                         bh->b_private = NULL;
 746                 }
 747                 gfs2_log_unlock(sdp);
 748                 if (bd)
 749                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 750
 751                 bh = bh->b_this_page;
 752         } while (bh != head);
 753
 754 out:
 755         return try_to_free_buffers(page);
 756 }
 757
 758 const struct address_space_operations gfs2_file_aops = {
 759         .writepage = gfs2_writepage,
 760         .readpage = gfs2_readpage,
 761         .readpages = gfs2_readpages,
 762         .sync_page = block_sync_page,
 763         .prepare_write = gfs2_prepare_write,
 764         .commit_write = gfs2_commit_write,
 765         .bmap = gfs2_bmap,
 766         .invalidatepage = gfs2_invalidatepage,
 767         .releasepage = gfs2_releasepage,
 768         .direct_IO = gfs2_direct_IO,
 769 };
 770