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 v.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
  21 #include "gfs2.h"
  22 #include "lm_interface.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 "page.h"
  31 #include "quota.h"
  32 #include "trans.h"
  33 #include "rgrp.h"
  34 #include "ops_file.h"
  35 #include "util.h"
  36 #include "glops.h"
  37
  38 /**
  39  * gfs2_get_block - Fills in a buffer head with details about a block
  40  * @inode: The inode
  41  * @lblock: The block number to look up
  42  * @bh_result: The buffer head to return the result in
  43  * @create: Non-zero if we may add block to the file
  44  *
  45  * Returns: errno
  46  */
  47
  48 int gfs2_get_block(struct inode *inode, sector_t lblock,
  49                    struct buffer_head *bh_result, int create)
  50 {
  51         int new = create;
  52         uint64_t dblock;
  53         int error;
  54         int boundary;
  55
  56         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
  57         if (error)
  58                 return error;
  59
  60         if (!dblock)
  61                 return 0;
  62
  63         map_bh(bh_result, inode->i_sb, dblock);
  64         if (new)
  65                 set_buffer_new(bh_result);
  66         if (boundary)
  67                 set_buffer_boundary(bh_result);
  68
  69         return 0;
  70 }
  71
  72 /**
  73  * get_block_noalloc - Fills in a buffer head with details about a block
  74  * @inode: The inode
  75  * @lblock: The block number to look up
  76  * @bh_result: The buffer head to return the result in
  77  * @create: Non-zero if we may add block to the file
  78  *
  79  * Returns: errno
  80  */
  81
  82 static int get_block_noalloc(struct inode *inode, sector_t lblock,
  83                              struct buffer_head *bh_result, int create)
  84 {
  85         int new = 0;
  86         uint64_t dblock;
  87         int error;
  88         int boundary;
  89
  90         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
  91         if (error)
  92                 return error;
  93
  94         if (dblock)
  95                 map_bh(bh_result, inode->i_sb, dblock);
  96         else if (gfs2_assert_withdraw(GFS2_SB(inode), !create))
  97                 error = -EIO;
  98         if (boundary)
  99                 set_buffer_boundary(bh_result);
 100
 101         return error;
 102 }
 103
 104 /**
 105  * gfs2_writepage - Write complete page
 106  * @page: Page to write
 107  *
 108  * Returns: errno
 109  *
 110  * Some of this is copied from block_write_full_page() although we still
 111  * call it to do most of the work.
 112  */
 113
 114 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 115 {
 116         struct inode *inode = page->mapping->host;
 117         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 118         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 119         loff_t i_size = i_size_read(inode);
 120         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 121         unsigned offset;
 122         int error;
 123         int done_trans = 0;
 124
 125         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 126                 unlock_page(page);
 127                 return -EIO;
 128         }
 129         if (current->journal_info)
 130                 goto out_ignore;
 131
 132         /* Is the page fully outside i_size? (truncate in progress) */
 133         offset = i_size & (PAGE_CACHE_SIZE-1);
 134         if (page->index > end_index || (page->index == end_index && !offset)) {
 135                 page->mapping->a_ops->invalidatepage(page, 0);
 136                 unlock_page(page);
 137                 return 0; /* don't care */
 138         }
 139
 140         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 141                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 142                 if (error)
 143                         goto out_ignore;
 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, 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 static int zero_readpage(struct page *page)
 160 {
 161         void *kaddr;
 162
 163         kaddr = kmap_atomic(page, KM_USER0);
 164         memset(kaddr, 0, PAGE_CACHE_SIZE);
 165         kunmap_atomic(page, KM_USER0);
 166
 167         SetPageUptodate(page);
 168
 169         return 0;
 170 }
 171
 172 /**
 173  * stuffed_readpage - Fill in a Linux page with stuffed file data
 174  * @ip: the inode
 175  * @page: the page
 176  *
 177  * Returns: errno
 178  */
 179
 180 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 181 {
 182         struct buffer_head *dibh;
 183         void *kaddr;
 184         int error;
 185
 186         /* Only the first page of a stuffed file might contain data */
 187         if (unlikely(page->index))
 188                 return zero_readpage(page);
 189
 190         error = gfs2_meta_inode_buffer(ip, &dibh);
 191         if (error)
 192                 return error;
 193
 194         kaddr = kmap_atomic(page, KM_USER0);
 195         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 196                ip->i_di.di_size);
 197         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 198         kunmap_atomic(page, KM_USER0);
 199
 200         brelse(dibh);
 201
 202         SetPageUptodate(page);
 203
 204         return 0;
 205 }
 206
 207
 208 /**
 209  * gfs2_readpage - readpage with locking
 210  * @file: The file to read a page for. N.B. This may be NULL if we are
 211  * reading an internal file.
 212  * @page: The page to read
 213  *
 214  * Returns: errno
 215  */
 216
 217 static int gfs2_readpage(struct file *file, struct page *page)
 218 {
 219         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 220         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 221         struct gfs2_holder gh;
 222         int error;
 223
 224         if (likely(file != &gfs2_internal_file_sentinal)) {
 225                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
 226                 error = gfs2_glock_nq_m_atime(1, &gh);
 227                 if (unlikely(error))
 228                         goto out_unlock;
 229         }
 230
 231         if (gfs2_is_stuffed(ip)) {
 232                 error = stuffed_readpage(ip, page);
 233                 unlock_page(page);
 234         } else
 235                 error = mpage_readpage(page, gfs2_get_block);
 236
 237         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 238                 error = -EIO;
 239
 240         if (file != &gfs2_internal_file_sentinal) {
 241                 gfs2_glock_dq_m(1, &gh);
 242                 gfs2_holder_uninit(&gh);
 243         }
 244 out:
 245         return error;
 246 out_unlock:
 247         unlock_page(page);
 248         if (file != &gfs2_internal_file_sentinal)
 249                 gfs2_holder_uninit(&gh);
 250         goto out;
 251 }
 252
 253 /**
 254  * gfs2_readpages - Read a bunch of pages at once
 255  *
 256  * Some notes:
 257  * 1. This is only for readahead, so we can simply ignore any things
 258  *    which are slightly inconvenient (such as locking conflicts between
 259  *    the page lock and the glock) and return having done no I/O. Its
 260  *    obviously not something we'd want to do on too regular a basis.
 261  *    Any I/O we ignore at this time will be done via readpage later.
 262  * 2. We have to handle stuffed files here too.
 263  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 264  * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
 265  * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
 266  *    well as read-ahead.
 267  */
 268 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 269                           struct list_head *pages, unsigned nr_pages)
 270 {
 271         struct inode *inode = mapping->host;
 272         struct gfs2_inode *ip = GFS2_I(inode);
 273         struct gfs2_sbd *sdp = GFS2_SB(inode);
 274         struct gfs2_holder gh;
 275         unsigned page_idx;
 276         int ret;
 277
 278         if (likely(file != &gfs2_internal_file_sentinal)) {
 279                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 280                                  LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
 281                 ret = gfs2_glock_nq_m_atime(1, &gh);
 282                 if (ret == GLR_TRYFAILED)
 283                         goto out_noerror;
 284                 if (unlikely(ret))
 285                         goto out_unlock;
 286         }
 287
 288         if (gfs2_is_stuffed(ip)) {
 289                 struct pagevec lru_pvec;
 290                 pagevec_init(&lru_pvec, 0);
 291                 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 292                         struct page *page = list_entry(pages->prev, struct page, lru);
 293                         prefetchw(&page->flags);
 294                         list_del(&page->lru);
 295                         if (!add_to_page_cache(page, mapping,
 296                                                page->index, GFP_KERNEL)) {
 297                                 ret = stuffed_readpage(ip, page);
 298                                 unlock_page(page);
 299                                 if (!pagevec_add(&lru_pvec, page))
 300                                          __pagevec_lru_add(&lru_pvec);
 301                         } else {
 302                                 page_cache_release(page);
 303                         }
 304                 }
 305                 pagevec_lru_add(&lru_pvec);
 306                 ret = 0;
 307         } else {
 308                 /* What we really want to do .... */
 309                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 310         }
 311
 312         if (likely(file != &gfs2_internal_file_sentinal)) {
 313                 gfs2_glock_dq_m(1, &gh);
 314                 gfs2_holder_uninit(&gh);
 315         }
 316 out:
 317         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 318                 ret = -EIO;
 319         return ret;
 320 out_noerror:
 321         ret = 0;
 322 out_unlock:
 323         /* unlock all pages, we can't do any I/O right now */
 324         for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 325                 struct page *page = list_entry(pages->prev, struct page, lru);
 326                 list_del(&page->lru);
 327                 unlock_page(page);
 328                 page_cache_release(page);
 329         }
 330         if (likely(file != &gfs2_internal_file_sentinal))
 331                 gfs2_holder_uninit(&gh);
 332         goto out;
 333 }
 334
 335 /**
 336  * gfs2_prepare_write - Prepare to write a page to a file
 337  * @file: The file to write to
 338  * @page: The page which is to be prepared for writing
 339  * @from: From (byte range within page)
 340  * @to: To (byte range within page)
 341  *
 342  * Returns: errno
 343  */
 344
 345 static int gfs2_prepare_write(struct file *file, struct page *page,
 346                               unsigned from, unsigned to)
 347 {
 348         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 349         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 350         unsigned int data_blocks, ind_blocks, rblocks;
 351         int alloc_required;
 352         int error = 0;
 353         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 354         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 355         struct gfs2_alloc *al;
 356
 357         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
 358         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 359         if (error)
 360                 goto out_uninit;
 361
 362         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 363
 364         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 365         if (error)
 366                 goto out_unlock;
 367
 368
 369         if (alloc_required) {
 370                 al = gfs2_alloc_get(ip);
 371
 372                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 373                 if (error)
 374                         goto out_alloc_put;
 375
 376                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 377                 if (error)
 378                         goto out_qunlock;
 379
 380                 al->al_requested = data_blocks + ind_blocks;
 381                 error = gfs2_inplace_reserve(ip);
 382                 if (error)
 383                         goto out_qunlock;
 384         }
 385
 386         rblocks = RES_DINODE + ind_blocks;
 387         if (gfs2_is_jdata(ip))
 388                 rblocks += data_blocks ? data_blocks : 1;
 389         if (ind_blocks || data_blocks)
 390                 rblocks += RES_STATFS + RES_QUOTA;
 391
 392         error = gfs2_trans_begin(sdp, rblocks, 0);
 393         if (error)
 394                 goto out;
 395
 396         if (gfs2_is_stuffed(ip)) {
 397                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 398                         error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
 399                                                     page);
 400                         if (error == 0)
 401                                 goto prepare_write;
 402                 } else if (!PageUptodate(page))
 403                         error = stuffed_readpage(ip, page);
 404                 goto out;
 405         }
 406
 407 prepare_write:
 408         error = block_prepare_write(page, from, to, gfs2_get_block);
 409
 410 out:
 411         if (error) {
 412                 gfs2_trans_end(sdp);
 413                 if (alloc_required) {
 414                         gfs2_inplace_release(ip);
 415 out_qunlock:
 416                         gfs2_quota_unlock(ip);
 417 out_alloc_put:
 418                         gfs2_alloc_put(ip);
 419                 }
 420 out_unlock:
 421                 gfs2_glock_dq_m(1, &ip->i_gh);
 422 out_uninit:
 423                 gfs2_holder_uninit(&ip->i_gh);
 424         }
 425
 426         return error;
 427 }
 428
 429 /**
 430  * gfs2_commit_write - Commit write to a file
 431  * @file: The file to write to
 432  * @page: The page containing the data
 433  * @from: From (byte range within page)
 434  * @to: To (byte range within page)
 435  *
 436  * Returns: errno
 437  */
 438
 439 static int gfs2_commit_write(struct file *file, struct page *page,
 440                              unsigned from, unsigned to)
 441 {
 442         struct inode *inode = page->mapping->host;
 443         struct gfs2_inode *ip = GFS2_I(inode);
 444         struct gfs2_sbd *sdp = GFS2_SB(inode);
 445         int error = -EOPNOTSUPP;
 446         struct buffer_head *dibh;
 447         struct gfs2_alloc *al = &ip->i_alloc;;
 448
 449         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 450                 goto fail_nounlock;
 451
 452         error = gfs2_meta_inode_buffer(ip, &dibh);
 453         if (error)
 454                 goto fail_endtrans;
 455
 456         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 457
 458         if (gfs2_is_stuffed(ip)) {
 459                 uint64_t file_size;
 460                 void *kaddr;
 461
 462                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 463
 464                 kaddr = kmap_atomic(page, KM_USER0);
 465                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 466                        (char *)kaddr + from, to - from);
 467                 kunmap_atomic(page, KM_USER0);
 468
 469                 SetPageUptodate(page);
 470
 471                 if (inode->i_size < file_size)
 472                         i_size_write(inode, file_size);
 473         } else {
 474                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 475                     gfs2_is_jdata(ip))
 476                         gfs2_page_add_databufs(ip, page, from, to);
 477                 error = generic_commit_write(file, page, from, to);
 478                 if (error)
 479                         goto fail;
 480         }
 481
 482         if (ip->i_di.di_size < inode->i_size)
 483                 ip->i_di.di_size = inode->i_size;
 484
 485         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 486         brelse(dibh);
 487         gfs2_trans_end(sdp);
 488         if (al->al_requested) {
 489                 gfs2_inplace_release(ip);
 490                 gfs2_quota_unlock(ip);
 491                 gfs2_alloc_put(ip);
 492         }
 493         gfs2_glock_dq_m(1, &ip->i_gh);
 494         gfs2_holder_uninit(&ip->i_gh);
 495         return 0;
 496
 497 fail:
 498         brelse(dibh);
 499 fail_endtrans:
 500         gfs2_trans_end(sdp);
 501         if (al->al_requested) {
 502                 gfs2_inplace_release(ip);
 503                 gfs2_quota_unlock(ip);
 504                 gfs2_alloc_put(ip);
 505         }
 506         gfs2_glock_dq_m(1, &ip->i_gh);
 507         gfs2_holder_uninit(&ip->i_gh);
 508 fail_nounlock:
 509         ClearPageUptodate(page);
 510         return error;
 511 }
 512
 513 /**
 514  * gfs2_bmap - Block map function
 515  * @mapping: Address space info
 516  * @lblock: The block to map
 517  *
 518  * Returns: The disk address for the block or 0 on hole or error
 519  */
 520
 521 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 522 {
 523         struct gfs2_inode *ip = GFS2_I(mapping->host);
 524         struct gfs2_holder i_gh;
 525         sector_t dblock = 0;
 526         int error;
 527
 528         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 529         if (error)
 530                 return 0;
 531
 532         if (!gfs2_is_stuffed(ip))
 533                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 534
 535         gfs2_glock_dq_uninit(&i_gh);
 536
 537         return dblock;
 538 }
 539
 540 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 541 {
 542         struct gfs2_bufdata *bd;
 543
 544         gfs2_log_lock(sdp);
 545         bd = bh->b_private;
 546         if (bd) {
 547                 bd->bd_bh = NULL;
 548                 bh->b_private = NULL;
 549                 gfs2_log_unlock(sdp);
 550                 brelse(bh);
 551         } else
 552                 gfs2_log_unlock(sdp);
 553
 554         lock_buffer(bh);
 555         clear_buffer_dirty(bh);
 556         bh->b_bdev = NULL;
 557         clear_buffer_mapped(bh);
 558         clear_buffer_req(bh);
 559         clear_buffer_new(bh);
 560         clear_buffer_delay(bh);
 561         unlock_buffer(bh);
 562 }
 563
 564 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 565 {
 566         struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
 567         struct buffer_head *head, *bh, *next;
 568         unsigned int curr_off = 0;
 569
 570         BUG_ON(!PageLocked(page));
 571         if (!page_has_buffers(page))
 572                 return;
 573
 574         bh = head = page_buffers(page);
 575         do {
 576                 unsigned int next_off = curr_off + bh->b_size;
 577                 next = bh->b_this_page;
 578
 579                 if (offset <= curr_off)
 580                         discard_buffer(sdp, bh);
 581
 582                 curr_off = next_off;
 583                 bh = next;
 584         } while (bh != head);
 585
 586         if (!offset)
 587                 try_to_release_page(page, 0);
 588
 589         return;
 590 }
 591
 592 static ssize_t gfs2_direct_IO_write(struct kiocb *iocb, const struct iovec *iov,
 593                                     loff_t offset, unsigned long nr_segs)
 594 {
 595         struct file *file = iocb->ki_filp;
 596         struct inode *inode = file->f_mapping->host;
 597         struct gfs2_inode *ip = GFS2_I(inode);
 598         struct gfs2_holder gh;
 599         int rv;
 600
 601         /*
 602          * Shared lock, even though its write, since we do no allocation
 603          * on this path. All we need change is atime.
 604          */
 605         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 606         rv = gfs2_glock_nq_m_atime(1, &gh);
 607         if (rv)
 608                 goto out;
 609
 610         /*
 611          * Should we return an error here? I can't see that O_DIRECT for
 612          * a journaled file makes any sense. For now we'll silently fall
 613          * back to buffered I/O, likewise we do the same for stuffed
 614          * files since they are (a) small and (b) unaligned.
 615          */
 616         if (gfs2_is_jdata(ip))
 617                 goto out;
 618
 619         if (gfs2_is_stuffed(ip))
 620                 goto out;
 621
 622         rv = __blockdev_direct_IO(WRITE, iocb, inode, inode->i_sb->s_bdev,
 623                                   iov, offset, nr_segs, gfs2_get_block,
 624                                   NULL, DIO_OWN_LOCKING);
 625 out:
 626         gfs2_glock_dq_m(1, &gh);
 627         gfs2_holder_uninit(&gh);
 628
 629         return rv;
 630 }
 631
 632 /**
 633  * gfs2_direct_IO
 634  *
 635  * This is called with a shared lock already held for the read path.
 636  * Currently, no locks are held when the write path is called.
 637  */
 638 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 639                               const struct iovec *iov, loff_t offset,
 640                               unsigned long nr_segs)
 641 {
 642         struct file *file = iocb->ki_filp;
 643         struct inode *inode = file->f_mapping->host;
 644         struct gfs2_inode *ip = GFS2_I(inode);
 645         struct gfs2_sbd *sdp = GFS2_SB(inode);
 646         int ret;
 647
 648         if (rw == WRITE)
 649                 return gfs2_direct_IO_write(iocb, iov, offset, nr_segs);
 650
 651         if (gfs2_assert_warn(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)) ||
 652             gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
 653                 return -EINVAL;
 654
 655         mutex_lock(&inode->i_mutex);
 656         ret = __blockdev_direct_IO(READ, iocb, inode, inode->i_sb->s_bdev, iov,
 657                                    offset, nr_segs, gfs2_get_block, NULL,
 658                                    DIO_OWN_LOCKING);
 659         mutex_unlock(&inode->i_mutex);
 660         return ret;
 661 }
 662
 663 /**
 664  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
 665  * @bh: the buffer we're stuck on
 666  *
 667  */
 668
 669 static void stuck_releasepage(struct buffer_head *bh)
 670 {
 671         struct inode *inode = bh->b_page->mapping->host;
 672         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 673         struct gfs2_bufdata *bd = bh->b_private;
 674         struct gfs2_glock *gl;
 675
 676         fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
 677         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
 678                 (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
 679         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
 680         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
 681
 682         if (!bd)
 683                 return;
 684
 685         gl = bd->bd_gl;
 686
 687         fs_warn(sdp, "gl = (%u, %llu)\n",
 688                 gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 689
 690         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
 691                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
 692                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 693
 694         if (gl->gl_ops == &gfs2_inode_glops) {
 695                 struct gfs2_inode *ip = gl->gl_object;
 696                 unsigned int x;
 697
 698                 if (!ip)
 699                         return;
 700
 701                 fs_warn(sdp, "ip = %llu %llu\n",
 702                         (unsigned long long)ip->i_num.no_formal_ino,
 703                         (unsigned long long)ip->i_num.no_addr);
 704
 705                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 706                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
 707                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
 708         }
 709 }
 710
 711 /**
 712  * gfs2_aspace_releasepage - free the metadata associated with a page
 713  * @page: the page that's being released
 714  * @gfp_mask: passed from Linux VFS, ignored by us
 715  *
 716  * Call try_to_free_buffers() if the buffers in this page can be
 717  * released.
 718  *
 719  * Returns: 0
 720  */
 721
 722 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 723 {
 724         struct inode *aspace = page->mapping->host;
 725         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
 726         struct buffer_head *bh, *head;
 727         struct gfs2_bufdata *bd;
 728         unsigned long t;
 729
 730         if (!page_has_buffers(page))
 731                 goto out;
 732
 733         head = bh = page_buffers(page);
 734         do {
 735                 t = jiffies;
 736
 737                 while (atomic_read(&bh->b_count)) {
 738                         if (atomic_read(&aspace->i_writecount)) {
 739                                 if (time_after_eq(jiffies, t +
 740                                     gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
 741                                         stuck_releasepage(bh);
 742                                         t = jiffies;
 743                                 }
 744
 745                                 yield();
 746                                 continue;
 747                         }
 748
 749                         return 0;
 750                 }
 751
 752                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 753
 754                 bd = bh->b_private;
 755                 if (bd) {
 756                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 757                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
 758                         gfs2_assert_warn(sdp, list_empty(&bd->bd_le.le_list));
 759                         gfs2_assert_warn(sdp, !bd->bd_ail);
 760                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 761                         bh->b_private = NULL;
 762                 }
 763
 764                 bh = bh->b_this_page;
 765         }
 766         while (bh != head);
 767
 768  out:
 769         return try_to_free_buffers(page);
 770 }
 771
 772 const struct address_space_operations gfs2_file_aops = {
 773         .writepage = gfs2_writepage,
 774         .readpage = gfs2_readpage,
 775         .readpages = gfs2_readpages,
 776         .sync_page = block_sync_page,
 777         .prepare_write = gfs2_prepare_write,
 778         .commit_write = gfs2_commit_write,
 779         .bmap = gfs2_bmap,
 780         .invalidatepage = gfs2_invalidatepage,
 781         .releasepage = gfs2_releasepage,
 782         .direct_IO = gfs2_direct_IO,
 783 };
 784