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
  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 "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         int new = create;
  69         u64 dblock;
  70         int error;
  71         int boundary;
  72
  73         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
  74         if (error)
  75                 return error;
  76
  77         if (!dblock)
  78                 return 0;
  79
  80         map_bh(bh_result, inode->i_sb, dblock);
  81         if (new)
  82                 set_buffer_new(bh_result);
  83         if (boundary)
  84                 set_buffer_boundary(bh_result);
  85
  86         return 0;
  87 }
  88
  89 /**
  90  * get_block_noalloc - Fills in a buffer head with details about a block
  91  * @inode: The inode
  92  * @lblock: The block number to look up
  93  * @bh_result: The buffer head to return the result in
  94  * @create: Non-zero if we may add block to the file
  95  *
  96  * Returns: errno
  97  */
  98
  99 static int get_block_noalloc(struct inode *inode, sector_t lblock,
 100                              struct buffer_head *bh_result, int create)
 101 {
 102         int new = 0;
 103         u64 dblock;
 104         int error;
 105         int boundary;
 106
 107         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
 108         if (error)
 109                 return error;
 110
 111         if (dblock)
 112                 map_bh(bh_result, inode->i_sb, dblock);
 113         else if (gfs2_assert_withdraw(GFS2_SB(inode), !create))
 114                 error = -EIO;
 115         if (boundary)
 116                 set_buffer_boundary(bh_result);
 117
 118         return error;
 119 }
 120
 121 static int get_block_direct(struct inode *inode, sector_t lblock,
 122                             struct buffer_head *bh_result, int create)
 123 {
 124         int new = 0;
 125         u64 dblock;
 126         int error, boundary;
 127
 128         error = gfs2_block_map(inode, lblock, &new, &dblock, &boundary);
 129         if (error)
 130                 return error;
 131
 132         if (dblock) {
 133                 map_bh(bh_result, inode->i_sb, dblock);
 134                 if (boundary)
 135                         set_buffer_boundary(bh_result);
 136         }
 137
 138         return 0;
 139 }
 140 /**
 141  * gfs2_writepage - Write complete page
 142  * @page: Page to write
 143  *
 144  * Returns: errno
 145  *
 146  * Some of this is copied from block_write_full_page() although we still
 147  * call it to do most of the work.
 148  */
 149
 150 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 151 {
 152         struct inode *inode = page->mapping->host;
 153         struct gfs2_inode *ip = GFS2_I(inode);
 154         struct gfs2_sbd *sdp = GFS2_SB(inode);
 155         loff_t i_size = i_size_read(inode);
 156         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 157         unsigned offset;
 158         int error;
 159         int done_trans = 0;
 160
 161         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 162                 unlock_page(page);
 163                 return -EIO;
 164         }
 165         if (current->journal_info)
 166                 goto out_ignore;
 167
 168         /* Is the page fully outside i_size? (truncate in progress) */
 169         offset = i_size & (PAGE_CACHE_SIZE-1);
 170         if (page->index > end_index || (page->index == end_index && !offset)) {
 171                 page->mapping->a_ops->invalidatepage(page, 0);
 172                 unlock_page(page);
 173                 return 0; /* don't care */
 174         }
 175
 176         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 177                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 178                 if (error)
 179                         goto out_ignore;
 180                 if (!page_has_buffers(page)) {
 181                         create_empty_buffers(page, inode->i_sb->s_blocksize,
 182                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
 183                 }
 184                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 185                 done_trans = 1;
 186         }
 187         error = block_write_full_page(page, get_block_noalloc, wbc);
 188         if (done_trans)
 189                 gfs2_trans_end(sdp);
 190         gfs2_meta_cache_flush(ip);
 191         return error;
 192
 193 out_ignore:
 194         redirty_page_for_writepage(wbc, page);
 195         unlock_page(page);
 196         return 0;
 197 }
 198
 199 static int zero_readpage(struct page *page)
 200 {
 201         void *kaddr;
 202
 203         kaddr = kmap_atomic(page, KM_USER0);
 204         memset(kaddr, 0, PAGE_CACHE_SIZE);
 205         kunmap_atomic(page, KM_USER0);
 206
 207         SetPageUptodate(page);
 208
 209         return 0;
 210 }
 211
 212 /**
 213  * stuffed_readpage - Fill in a Linux page with stuffed file data
 214  * @ip: the inode
 215  * @page: the page
 216  *
 217  * Returns: errno
 218  */
 219
 220 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 221 {
 222         struct buffer_head *dibh;
 223         void *kaddr;
 224         int error;
 225
 226         /* Only the first page of a stuffed file might contain data */
 227         if (unlikely(page->index))
 228                 return zero_readpage(page);
 229
 230         error = gfs2_meta_inode_buffer(ip, &dibh);
 231         if (error)
 232                 return error;
 233
 234         kaddr = kmap_atomic(page, KM_USER0);
 235         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 236                ip->i_di.di_size);
 237         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 238         kunmap_atomic(page, KM_USER0);
 239
 240         brelse(dibh);
 241
 242         SetPageUptodate(page);
 243
 244         return 0;
 245 }
 246
 247
 248 /**
 249  * gfs2_readpage - readpage with locking
 250  * @file: The file to read a page for. N.B. This may be NULL if we are
 251  * reading an internal file.
 252  * @page: The page to read
 253  *
 254  * Returns: errno
 255  */
 256
 257 static int gfs2_readpage(struct file *file, struct page *page)
 258 {
 259         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 260         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 261         struct gfs2_holder gh;
 262         int error;
 263         int do_unlock = 0;
 264
 265         if (likely(file != &gfs2_internal_file_sentinel)) {
 266                 if (file) {
 267                         struct gfs2_file *gf = file->private_data;
 268                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 269                                 goto skip_lock;
 270                 }
 271                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
 272                 do_unlock = 1;
 273                 error = gfs2_glock_nq_m_atime(1, &gh);
 274                 if (unlikely(error))
 275                         goto out_unlock;
 276         }
 277
 278 skip_lock:
 279         if (gfs2_is_stuffed(ip)) {
 280                 error = stuffed_readpage(ip, page);
 281                 unlock_page(page);
 282         } else
 283                 error = mpage_readpage(page, gfs2_get_block);
 284
 285         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 286                 error = -EIO;
 287
 288         if (file != &gfs2_internal_file_sentinel) {
 289                 gfs2_glock_dq_m(1, &gh);
 290                 gfs2_holder_uninit(&gh);
 291         }
 292 out:
 293         return error;
 294 out_unlock:
 295         unlock_page(page);
 296         if (do_unlock)
 297                 gfs2_holder_uninit(&gh);
 298         goto out;
 299 }
 300
 301 /**
 302  * gfs2_readpages - Read a bunch of pages at once
 303  *
 304  * Some notes:
 305  * 1. This is only for readahead, so we can simply ignore any things
 306  *    which are slightly inconvenient (such as locking conflicts between
 307  *    the page lock and the glock) and return having done no I/O. Its
 308  *    obviously not something we'd want to do on too regular a basis.
 309  *    Any I/O we ignore at this time will be done via readpage later.
 310  * 2. We have to handle stuffed files here too.
 311  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 312  * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
 313  * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
 314  *    well as read-ahead.
 315  */
 316 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 317                           struct list_head *pages, unsigned nr_pages)
 318 {
 319         struct inode *inode = mapping->host;
 320         struct gfs2_inode *ip = GFS2_I(inode);
 321         struct gfs2_sbd *sdp = GFS2_SB(inode);
 322         struct gfs2_holder gh;
 323         unsigned page_idx;
 324         int ret;
 325         int do_unlock = 0;
 326
 327         if (likely(file != &gfs2_internal_file_sentinel)) {
 328                 if (file) {
 329                         struct gfs2_file *gf = file->private_data;
 330                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 331                                 goto skip_lock;
 332                 }
 333                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 334                                  LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
 335                 do_unlock = 1;
 336                 ret = gfs2_glock_nq_m_atime(1, &gh);
 337                 if (ret == GLR_TRYFAILED)
 338                         goto out_noerror;
 339                 if (unlikely(ret))
 340                         goto out_unlock;
 341         }
 342 skip_lock:
 343         if (gfs2_is_stuffed(ip)) {
 344                 struct pagevec lru_pvec;
 345                 pagevec_init(&lru_pvec, 0);
 346                 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 347                         struct page *page = list_entry(pages->prev, struct page, lru);
 348                         prefetchw(&page->flags);
 349                         list_del(&page->lru);
 350                         if (!add_to_page_cache(page, mapping,
 351                                                page->index, GFP_KERNEL)) {
 352                                 ret = stuffed_readpage(ip, page);
 353                                 unlock_page(page);
 354                                 if (!pagevec_add(&lru_pvec, page))
 355                                          __pagevec_lru_add(&lru_pvec);
 356                         } else {
 357                                 page_cache_release(page);
 358                         }
 359                 }
 360                 pagevec_lru_add(&lru_pvec);
 361                 ret = 0;
 362         } else {
 363                 /* What we really want to do .... */
 364                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 365         }
 366
 367         if (do_unlock) {
 368                 gfs2_glock_dq_m(1, &gh);
 369                 gfs2_holder_uninit(&gh);
 370         }
 371 out:
 372         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 373                 ret = -EIO;
 374         return ret;
 375 out_noerror:
 376         ret = 0;
 377 out_unlock:
 378         /* unlock all pages, we can't do any I/O right now */
 379         for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 380                 struct page *page = list_entry(pages->prev, struct page, lru);
 381                 list_del(&page->lru);
 382                 unlock_page(page);
 383                 page_cache_release(page);
 384         }
 385         if (do_unlock)
 386                 gfs2_holder_uninit(&gh);
 387         goto out;
 388 }
 389
 390 /**
 391  * gfs2_prepare_write - Prepare to write a page to a file
 392  * @file: The file to write to
 393  * @page: The page which is to be prepared for writing
 394  * @from: From (byte range within page)
 395  * @to: To (byte range within page)
 396  *
 397  * Returns: errno
 398  */
 399
 400 static int gfs2_prepare_write(struct file *file, struct page *page,
 401                               unsigned from, unsigned to)
 402 {
 403         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 404         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 405         unsigned int data_blocks, ind_blocks, rblocks;
 406         int alloc_required;
 407         int error = 0;
 408         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 409         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 410         struct gfs2_alloc *al;
 411
 412         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
 413         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 414         if (error)
 415                 goto out_uninit;
 416
 417         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 418
 419         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 420         if (error)
 421                 goto out_unlock;
 422
 423
 424         if (alloc_required) {
 425                 al = gfs2_alloc_get(ip);
 426
 427                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 428                 if (error)
 429                         goto out_alloc_put;
 430
 431                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 432                 if (error)
 433                         goto out_qunlock;
 434
 435                 al->al_requested = data_blocks + ind_blocks;
 436                 error = gfs2_inplace_reserve(ip);
 437                 if (error)
 438                         goto out_qunlock;
 439         }
 440
 441         rblocks = RES_DINODE + ind_blocks;
 442         if (gfs2_is_jdata(ip))
 443                 rblocks += data_blocks ? data_blocks : 1;
 444         if (ind_blocks || data_blocks)
 445                 rblocks += RES_STATFS + RES_QUOTA;
 446
 447         error = gfs2_trans_begin(sdp, rblocks, 0);
 448         if (error)
 449                 goto out;
 450
 451         if (gfs2_is_stuffed(ip)) {
 452                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 453                         error = gfs2_unstuff_dinode(ip, page);
 454                         if (error == 0)
 455                                 goto prepare_write;
 456                 } else if (!PageUptodate(page))
 457                         error = stuffed_readpage(ip, page);
 458                 goto out;
 459         }
 460
 461 prepare_write:
 462         error = block_prepare_write(page, from, to, gfs2_get_block);
 463
 464 out:
 465         if (error) {
 466                 gfs2_trans_end(sdp);
 467                 if (alloc_required) {
 468                         gfs2_inplace_release(ip);
 469 out_qunlock:
 470                         gfs2_quota_unlock(ip);
 471 out_alloc_put:
 472                         gfs2_alloc_put(ip);
 473                 }
 474 out_unlock:
 475                 gfs2_glock_dq_m(1, &ip->i_gh);
 476 out_uninit:
 477                 gfs2_holder_uninit(&ip->i_gh);
 478         }
 479
 480         return error;
 481 }
 482
 483 /**
 484  * gfs2_commit_write - Commit write to a file
 485  * @file: The file to write to
 486  * @page: The page containing the data
 487  * @from: From (byte range within page)
 488  * @to: To (byte range within page)
 489  *
 490  * Returns: errno
 491  */
 492
 493 static int gfs2_commit_write(struct file *file, struct page *page,
 494                              unsigned from, unsigned to)
 495 {
 496         struct inode *inode = page->mapping->host;
 497         struct gfs2_inode *ip = GFS2_I(inode);
 498         struct gfs2_sbd *sdp = GFS2_SB(inode);
 499         int error = -EOPNOTSUPP;
 500         struct buffer_head *dibh;
 501         struct gfs2_alloc *al = &ip->i_alloc;;
 502
 503         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 504                 goto fail_nounlock;
 505
 506         error = gfs2_meta_inode_buffer(ip, &dibh);
 507         if (error)
 508                 goto fail_endtrans;
 509
 510         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 511
 512         if (gfs2_is_stuffed(ip)) {
 513                 u64 file_size;
 514                 void *kaddr;
 515
 516                 file_size = ((u64)page->index << PAGE_CACHE_SHIFT) + to;
 517
 518                 kaddr = kmap_atomic(page, KM_USER0);
 519                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 520                        kaddr + from, to - from);
 521                 kunmap_atomic(page, KM_USER0);
 522
 523                 SetPageUptodate(page);
 524
 525                 if (inode->i_size < file_size)
 526                         i_size_write(inode, file_size);
 527         } else {
 528                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 529                     gfs2_is_jdata(ip))
 530                         gfs2_page_add_databufs(ip, page, from, to);
 531                 error = generic_commit_write(file, page, from, to);
 532                 if (error)
 533                         goto fail;
 534         }
 535
 536         if (ip->i_di.di_size < inode->i_size)
 537                 ip->i_di.di_size = inode->i_size;
 538
 539         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 540         brelse(dibh);
 541         gfs2_trans_end(sdp);
 542         if (al->al_requested) {
 543                 gfs2_inplace_release(ip);
 544                 gfs2_quota_unlock(ip);
 545                 gfs2_alloc_put(ip);
 546         }
 547         gfs2_glock_dq_m(1, &ip->i_gh);
 548         gfs2_holder_uninit(&ip->i_gh);
 549         return 0;
 550
 551 fail:
 552         brelse(dibh);
 553 fail_endtrans:
 554         gfs2_trans_end(sdp);
 555         if (al->al_requested) {
 556                 gfs2_inplace_release(ip);
 557                 gfs2_quota_unlock(ip);
 558                 gfs2_alloc_put(ip);
 559         }
 560         gfs2_glock_dq_m(1, &ip->i_gh);
 561         gfs2_holder_uninit(&ip->i_gh);
 562 fail_nounlock:
 563         ClearPageUptodate(page);
 564         return error;
 565 }
 566
 567 /**
 568  * gfs2_bmap - Block map function
 569  * @mapping: Address space info
 570  * @lblock: The block to map
 571  *
 572  * Returns: The disk address for the block or 0 on hole or error
 573  */
 574
 575 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 576 {
 577         struct gfs2_inode *ip = GFS2_I(mapping->host);
 578         struct gfs2_holder i_gh;
 579         sector_t dblock = 0;
 580         int error;
 581
 582         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 583         if (error)
 584                 return 0;
 585
 586         if (!gfs2_is_stuffed(ip))
 587                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 588
 589         gfs2_glock_dq_uninit(&i_gh);
 590
 591         return dblock;
 592 }
 593
 594 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 595 {
 596         struct gfs2_bufdata *bd;
 597
 598         gfs2_log_lock(sdp);
 599         bd = bh->b_private;
 600         if (bd) {
 601                 bd->bd_bh = NULL;
 602                 bh->b_private = NULL;
 603         }
 604         gfs2_log_unlock(sdp);
 605
 606         lock_buffer(bh);
 607         clear_buffer_dirty(bh);
 608         bh->b_bdev = NULL;
 609         clear_buffer_mapped(bh);
 610         clear_buffer_req(bh);
 611         clear_buffer_new(bh);
 612         clear_buffer_delay(bh);
 613         unlock_buffer(bh);
 614 }
 615
 616 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 617 {
 618         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 619         struct buffer_head *head, *bh, *next;
 620         unsigned int curr_off = 0;
 621
 622         BUG_ON(!PageLocked(page));
 623         if (!page_has_buffers(page))
 624                 return;
 625
 626         bh = head = page_buffers(page);
 627         do {
 628                 unsigned int next_off = curr_off + bh->b_size;
 629                 next = bh->b_this_page;
 630
 631                 if (offset <= curr_off)
 632                         discard_buffer(sdp, bh);
 633
 634                 curr_off = next_off;
 635                 bh = next;
 636         } while (bh != head);
 637
 638         if (!offset)
 639                 try_to_release_page(page, 0);
 640
 641         return;
 642 }
 643
 644 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 645                               const struct iovec *iov, loff_t offset,
 646                               unsigned long nr_segs)
 647 {
 648         struct file *file = iocb->ki_filp;
 649         struct inode *inode = file->f_mapping->host;
 650         struct gfs2_inode *ip = GFS2_I(inode);
 651         struct gfs2_holder gh;
 652         int rv;
 653
 654         if (rw == READ)
 655                 mutex_lock(&inode->i_mutex);
 656         /*
 657          * Shared lock, even if its a write, since we do no allocation
 658          * on this path. All we need change is atime.
 659          */
 660         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 661         rv = gfs2_glock_nq_m_atime(1, &gh);
 662         if (rv)
 663                 goto out;
 664
 665         if (offset > i_size_read(inode))
 666                 goto out;
 667
 668         /*
 669          * Should we return an error here? I can't see that O_DIRECT for
 670          * a journaled file makes any sense. For now we'll silently fall
 671          * back to buffered I/O, likewise we do the same for stuffed
 672          * files since they are (a) small and (b) unaligned.
 673          */
 674         if (gfs2_is_jdata(ip))
 675                 goto out;
 676
 677         if (gfs2_is_stuffed(ip))
 678                 goto out;
 679
 680         rv = blockdev_direct_IO_own_locking(rw, iocb, inode,
 681                                             inode->i_sb->s_bdev,
 682                                             iov, offset, nr_segs,
 683                                             get_block_direct, NULL);
 684 out:
 685         gfs2_glock_dq_m(1, &gh);
 686         gfs2_holder_uninit(&gh);
 687         if (rw == READ)
 688                 mutex_unlock(&inode->i_mutex);
 689
 690         return rv;
 691 }
 692
 693 /**
 694  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
 695  * @bh: the buffer we're stuck on
 696  *
 697  */
 698
 699 static void stuck_releasepage(struct buffer_head *bh)
 700 {
 701         struct inode *inode = bh->b_page->mapping->host;
 702         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 703         struct gfs2_bufdata *bd = bh->b_private;
 704         struct gfs2_glock *gl;
 705 static unsigned limit = 0;
 706
 707         if (limit > 3)
 708                 return;
 709         limit++;
 710
 711         fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
 712         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
 713                 (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
 714         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
 715         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
 716
 717         if (!bd)
 718                 return;
 719
 720         gl = bd->bd_gl;
 721
 722         fs_warn(sdp, "gl = (%u, %llu)\n",
 723                 gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 724
 725         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
 726                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
 727                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 728
 729         if (gl->gl_ops == &gfs2_inode_glops) {
 730                 struct gfs2_inode *ip = gl->gl_object;
 731                 unsigned int x;
 732
 733                 if (!ip)
 734                         return;
 735
 736                 fs_warn(sdp, "ip = %llu %llu\n",
 737                         (unsigned long long)ip->i_num.no_formal_ino,
 738                         (unsigned long long)ip->i_num.no_addr);
 739
 740                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 741                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
 742                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
 743         }
 744 }
 745
 746 /**
 747  * gfs2_releasepage - free the metadata associated with a page
 748  * @page: the page that's being released
 749  * @gfp_mask: passed from Linux VFS, ignored by us
 750  *
 751  * Call try_to_free_buffers() if the buffers in this page can be
 752  * released.
 753  *
 754  * Returns: 0
 755  */
 756
 757 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 758 {
 759         struct inode *aspace = page->mapping->host;
 760         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
 761         struct buffer_head *bh, *head;
 762         struct gfs2_bufdata *bd;
 763         unsigned long t = jiffies + gfs2_tune_get(sdp, gt_stall_secs) * HZ;
 764
 765         if (!page_has_buffers(page))
 766                 goto out;
 767
 768         head = bh = page_buffers(page);
 769         do {
 770                 while (atomic_read(&bh->b_count)) {
 771                         if (!atomic_read(&aspace->i_writecount))
 772                                 return 0;
 773
 774                         if (time_after_eq(jiffies, t)) {
 775                                 stuck_releasepage(bh);
 776                                 /* should we withdraw here? */
 777                                 return 0;
 778                         }
 779
 780                         yield();
 781                 }
 782
 783                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 784                 gfs2_assert_warn(sdp, !buffer_dirty(bh));
 785
 786                 gfs2_log_lock(sdp);
 787                 bd = bh->b_private;
 788                 if (bd) {
 789                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 790                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
 791                         gfs2_assert_warn(sdp, !bd->bd_ail);
 792                         bd->bd_bh = NULL;
 793                         if (!list_empty(&bd->bd_le.le_list))
 794                                 bd = NULL;
 795                         bh->b_private = NULL;
 796                 }
 797                 gfs2_log_unlock(sdp);
 798                 if (bd)
 799                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 800
 801                 bh = bh->b_this_page;
 802         } while (bh != head);
 803
 804 out:
 805         return try_to_free_buffers(page);
 806 }
 807
 808 const struct address_space_operations gfs2_file_aops = {
 809         .writepage = gfs2_writepage,
 810         .readpage = gfs2_readpage,
 811         .readpages = gfs2_readpages,
 812         .sync_page = block_sync_page,
 813         .prepare_write = gfs2_prepare_write,
 814         .commit_write = gfs2_commit_write,
 815         .bmap = gfs2_bmap,
 816         .invalidatepage = gfs2_invalidatepage,
 817         .releasepage = gfs2_releasepage,
 818         .direct_IO = gfs2_direct_IO,
 819 };
 820