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/writeback.h>
  20 #include <linux/gfs2_ondisk.h>
  21 #include <linux/lm_interface.h>
  22
  23 #include "gfs2.h"
  24 #include "incore.h"
  25 #include "bmap.h"
  26 #include "glock.h"
  27 #include "inode.h"
  28 #include "log.h"
  29 #include "meta_io.h"
  30 #include "ops_address.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 static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
  40                                    unsigned int from, unsigned int to)
  41 {
  42         struct buffer_head *head = page_buffers(page);
  43         unsigned int bsize = head->b_size;
  44         struct buffer_head *bh;
  45         unsigned int start, end;
  46
  47         for (bh = head, start = 0; bh != head || !start;
  48              bh = bh->b_this_page, start = end) {
  49                 end = start + bsize;
  50                 if (end <= from || start >= to)
  51                         continue;
  52                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
  53         }
  54 }
  55
  56 /**
  57  * gfs2_get_block - Fills in a buffer head with details about a block
  58  * @inode: The inode
  59  * @lblock: The block number to look up
  60  * @bh_result: The buffer head to return the result in
  61  * @create: Non-zero if we may add block to the file
  62  *
  63  * Returns: errno
  64  */
  65
  66 int gfs2_get_block(struct inode *inode, sector_t lblock,
  67                    struct buffer_head *bh_result, int create)
  68 {
  69         return gfs2_block_map(inode, lblock, create, bh_result);
  70 }
  71
  72 /**
  73  * gfs2_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 gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
  83                                   struct buffer_head *bh_result, int create)
  84 {
  85         int error;
  86
  87         error = gfs2_block_map(inode, lblock, 0, bh_result);
  88         if (error)
  89                 return error;
  90         if (bh_result->b_blocknr == 0)
  91                 return -EIO;
  92         return 0;
  93 }
  94
  95 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
  96                                  struct buffer_head *bh_result, int create)
  97 {
  98         return gfs2_block_map(inode, lblock, 0, bh_result);
  99 }
 100
 101 /**
 102  * gfs2_writepage - Write complete page
 103  * @page: Page to write
 104  *
 105  * Returns: errno
 106  *
 107  * Some of this is copied from block_write_full_page() although we still
 108  * call it to do most of the work.
 109  */
 110
 111 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 112 {
 113         struct inode *inode = page->mapping->host;
 114         struct gfs2_inode *ip = GFS2_I(inode);
 115         struct gfs2_sbd *sdp = GFS2_SB(inode);
 116         loff_t i_size = i_size_read(inode);
 117         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 118         unsigned offset;
 119         int error;
 120         int done_trans = 0;
 121
 122         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 123                 unlock_page(page);
 124                 return -EIO;
 125         }
 126         if (current->journal_info)
 127                 goto out_ignore;
 128
 129         /* Is the page fully outside i_size? (truncate in progress) */
 130         offset = i_size & (PAGE_CACHE_SIZE-1);
 131         if (page->index > end_index || (page->index == end_index && !offset)) {
 132                 page->mapping->a_ops->invalidatepage(page, 0);
 133                 unlock_page(page);
 134                 return 0; /* don't care */
 135         }
 136
 137         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 138                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 139                 if (error)
 140                         goto out_ignore;
 141                 if (!page_has_buffers(page)) {
 142                         create_empty_buffers(page, inode->i_sb->s_blocksize,
 143                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
 144                 }
 145                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 146                 done_trans = 1;
 147         }
 148         error = block_write_full_page(page, gfs2_get_block_noalloc, wbc);
 149         if (done_trans)
 150                 gfs2_trans_end(sdp);
 151         gfs2_meta_cache_flush(ip);
 152         return error;
 153
 154 out_ignore:
 155         redirty_page_for_writepage(wbc, page);
 156         unlock_page(page);
 157         return 0;
 158 }
 159
 160 /**
 161  * gfs2_writepages - Write a bunch of dirty pages back to disk
 162  * @mapping: The mapping to write
 163  * @wbc: Write-back control
 164  *
 165  * For journaled files and/or ordered writes this just falls back to the
 166  * kernel's default writepages path for now. We will probably want to change
 167  * that eventually (i.e. when we look at allocate on flush).
 168  *
 169  * For the data=writeback case though we can already ignore buffer heads
 170  * and write whole extents at once. This is a big reduction in the
 171  * number of I/O requests we send and the bmap calls we make in this case.
 172  */
 173 int gfs2_writepages(struct address_space *mapping, struct writeback_control *wbc)
 174 {
 175         struct inode *inode = mapping->host;
 176         struct gfs2_inode *ip = GFS2_I(inode);
 177         struct gfs2_sbd *sdp = GFS2_SB(inode);
 178
 179         if (sdp->sd_args.ar_data == GFS2_DATA_WRITEBACK && !gfs2_is_jdata(ip))
 180                 return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
 181
 182         return generic_writepages(mapping, wbc);
 183 }
 184
 185 /**
 186  * stuffed_readpage - Fill in a Linux page with stuffed file data
 187  * @ip: the inode
 188  * @page: the page
 189  *
 190  * Returns: errno
 191  */
 192
 193 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 194 {
 195         struct buffer_head *dibh;
 196         void *kaddr;
 197         int error;
 198
 199         BUG_ON(page->index);
 200
 201         error = gfs2_meta_inode_buffer(ip, &dibh);
 202         if (error)
 203                 return error;
 204
 205         kaddr = kmap_atomic(page, KM_USER0);
 206         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 207                ip->i_di.di_size);
 208         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 209         kunmap_atomic(kaddr, KM_USER0);
 210
 211         brelse(dibh);
 212
 213         SetPageUptodate(page);
 214
 215         return 0;
 216 }
 217
 218
 219 /**
 220  * gfs2_readpage - readpage with locking
 221  * @file: The file to read a page for. N.B. This may be NULL if we are
 222  * reading an internal file.
 223  * @page: The page to read
 224  *
 225  * Returns: errno
 226  */
 227
 228 static int gfs2_readpage(struct file *file, struct page *page)
 229 {
 230         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 231         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 232         struct gfs2_file *gf = NULL;
 233         struct gfs2_holder gh;
 234         int error;
 235         int do_unlock = 0;
 236
 237         if (likely(file != &gfs2_internal_file_sentinel)) {
 238                 if (file) {
 239                         gf = file->private_data;
 240                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 241                                 /* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */
 242                                 goto skip_lock;
 243                 }
 244                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
 245                 do_unlock = 1;
 246                 error = gfs2_glock_nq_atime(&gh);
 247                 if (unlikely(error))
 248                         goto out_unlock;
 249         }
 250
 251 skip_lock:
 252         if (gfs2_is_stuffed(ip)) {
 253                 error = stuffed_readpage(ip, page);
 254                 unlock_page(page);
 255         } else
 256                 error = mpage_readpage(page, gfs2_get_block);
 257
 258         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 259                 error = -EIO;
 260
 261         if (do_unlock) {
 262                 gfs2_glock_dq_m(1, &gh);
 263                 gfs2_holder_uninit(&gh);
 264         }
 265 out:
 266         return error;
 267 out_unlock:
 268         if (error == GLR_TRYFAILED)
 269                 error = AOP_TRUNCATED_PAGE;
 270         unlock_page(page);
 271         if (do_unlock)
 272                 gfs2_holder_uninit(&gh);
 273         goto out;
 274 }
 275
 276 /**
 277  * gfs2_readpages - Read a bunch of pages at once
 278  *
 279  * Some notes:
 280  * 1. This is only for readahead, so we can simply ignore any things
 281  *    which are slightly inconvenient (such as locking conflicts between
 282  *    the page lock and the glock) and return having done no I/O. Its
 283  *    obviously not something we'd want to do on too regular a basis.
 284  *    Any I/O we ignore at this time will be done via readpage later.
 285  * 2. We don't handle stuffed files here we let readpage do the honours.
 286  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 287  * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
 288  * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
 289  *    well as read-ahead.
 290  */
 291 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 292                           struct list_head *pages, unsigned nr_pages)
 293 {
 294         struct inode *inode = mapping->host;
 295         struct gfs2_inode *ip = GFS2_I(inode);
 296         struct gfs2_sbd *sdp = GFS2_SB(inode);
 297         struct gfs2_holder gh;
 298         int ret = 0;
 299         int do_unlock = 0;
 300
 301         if (likely(file != &gfs2_internal_file_sentinel)) {
 302                 if (file) {
 303                         struct gfs2_file *gf = file->private_data;
 304                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 305                                 goto skip_lock;
 306                 }
 307                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 308                                  LM_FLAG_TRY_1CB|GL_ATIME, &gh);
 309                 do_unlock = 1;
 310                 ret = gfs2_glock_nq_atime(&gh);
 311                 if (ret == GLR_TRYFAILED)
 312                         goto out_noerror;
 313                 if (unlikely(ret))
 314                         goto out_unlock;
 315         }
 316 skip_lock:
 317         if (!gfs2_is_stuffed(ip))
 318                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 319
 320         if (do_unlock) {
 321                 gfs2_glock_dq_m(1, &gh);
 322                 gfs2_holder_uninit(&gh);
 323         }
 324 out:
 325         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 326                 ret = -EIO;
 327         return ret;
 328 out_noerror:
 329         ret = 0;
 330 out_unlock:
 331         if (do_unlock)
 332                 gfs2_holder_uninit(&gh);
 333         goto out;
 334 }
 335
 336 /**
 337  * gfs2_prepare_write - Prepare to write a page to a file
 338  * @file: The file to write to
 339  * @page: The page which is to be prepared for writing
 340  * @from: From (byte range within page)
 341  * @to: To (byte range within page)
 342  *
 343  * Returns: errno
 344  */
 345
 346 static int gfs2_prepare_write(struct file *file, struct page *page,
 347                               unsigned from, unsigned to)
 348 {
 349         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 350         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 351         unsigned int data_blocks, ind_blocks, rblocks;
 352         int alloc_required;
 353         int error = 0;
 354         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 355         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 356         struct gfs2_alloc *al;
 357         unsigned int write_len = to - from;
 358
 359
 360         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
 361         error = gfs2_glock_nq_atime(&ip->i_gh);
 362         if (unlikely(error)) {
 363                 if (error == GLR_TRYFAILED)
 364                         error = AOP_TRUNCATED_PAGE;
 365                 goto out_uninit;
 366         }
 367
 368         gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
 369
 370         error = gfs2_write_alloc_required(ip, pos, write_len, &alloc_required);
 371         if (error)
 372                 goto out_unlock;
 373
 374
 375         ip->i_alloc.al_requested = 0;
 376         if (alloc_required) {
 377                 al = gfs2_alloc_get(ip);
 378
 379                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 380                 if (error)
 381                         goto out_alloc_put;
 382
 383                 error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
 384                 if (error)
 385                         goto out_qunlock;
 386
 387                 al->al_requested = data_blocks + ind_blocks;
 388                 error = gfs2_inplace_reserve(ip);
 389                 if (error)
 390                         goto out_qunlock;
 391         }
 392
 393         rblocks = RES_DINODE + ind_blocks;
 394         if (gfs2_is_jdata(ip))
 395                 rblocks += data_blocks ? data_blocks : 1;
 396         if (ind_blocks || data_blocks)
 397                 rblocks += RES_STATFS + RES_QUOTA;
 398
 399         error = gfs2_trans_begin(sdp, rblocks, 0);
 400         if (error)
 401                 goto out;
 402
 403         if (gfs2_is_stuffed(ip)) {
 404                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 405                         error = gfs2_unstuff_dinode(ip, page);
 406                         if (error == 0)
 407                                 goto prepare_write;
 408                 } else if (!PageUptodate(page))
 409                         error = stuffed_readpage(ip, page);
 410                 goto out;
 411         }
 412
 413 prepare_write:
 414         error = block_prepare_write(page, from, to, gfs2_get_block);
 415
 416 out:
 417         if (error) {
 418                 gfs2_trans_end(sdp);
 419                 if (alloc_required) {
 420                         gfs2_inplace_release(ip);
 421 out_qunlock:
 422                         gfs2_quota_unlock(ip);
 423 out_alloc_put:
 424                         gfs2_alloc_put(ip);
 425                 }
 426 out_unlock:
 427                 gfs2_glock_dq_m(1, &ip->i_gh);
 428 out_uninit:
 429                 gfs2_holder_uninit(&ip->i_gh);
 430         }
 431
 432         return error;
 433 }
 434
 435 /**
 436  * gfs2_commit_write - Commit write to a file
 437  * @file: The file to write to
 438  * @page: The page containing the data
 439  * @from: From (byte range within page)
 440  * @to: To (byte range within page)
 441  *
 442  * Returns: errno
 443  */
 444
 445 static int gfs2_commit_write(struct file *file, struct page *page,
 446                              unsigned from, unsigned to)
 447 {
 448         struct inode *inode = page->mapping->host;
 449         struct gfs2_inode *ip = GFS2_I(inode);
 450         struct gfs2_sbd *sdp = GFS2_SB(inode);
 451         int error = -EOPNOTSUPP;
 452         struct buffer_head *dibh;
 453         struct gfs2_alloc *al = &ip->i_alloc;
 454         struct gfs2_dinode *di;
 455
 456         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 457                 goto fail_nounlock;
 458
 459         error = gfs2_meta_inode_buffer(ip, &dibh);
 460         if (error)
 461                 goto fail_endtrans;
 462
 463         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 464         di = (struct gfs2_dinode *)dibh->b_data;
 465
 466         if (gfs2_is_stuffed(ip)) {
 467                 u64 file_size;
 468                 void *kaddr;
 469
 470                 file_size = ((u64)page->index << PAGE_CACHE_SHIFT) + to;
 471
 472                 kaddr = kmap_atomic(page, KM_USER0);
 473                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 474                        kaddr + from, to - from);
 475                 kunmap_atomic(kaddr, KM_USER0);
 476
 477                 SetPageUptodate(page);
 478
 479                 if (inode->i_size < file_size) {
 480                         i_size_write(inode, file_size);
 481                         mark_inode_dirty(inode);
 482                 }
 483         } else {
 484                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 485                     gfs2_is_jdata(ip))
 486                         gfs2_page_add_databufs(ip, page, from, to);
 487                 error = generic_commit_write(file, page, from, to);
 488                 if (error)
 489                         goto fail;
 490         }
 491
 492         if (ip->i_di.di_size < inode->i_size) {
 493                 ip->i_di.di_size = inode->i_size;
 494                 di->di_size = cpu_to_be64(inode->i_size);
 495         }
 496
 497         brelse(dibh);
 498         gfs2_trans_end(sdp);
 499         if (al->al_requested) {
 500                 gfs2_inplace_release(ip);
 501                 gfs2_quota_unlock(ip);
 502                 gfs2_alloc_put(ip);
 503         }
 504         gfs2_glock_dq_m(1, &ip->i_gh);
 505         gfs2_holder_uninit(&ip->i_gh);
 506         return 0;
 507
 508 fail:
 509         brelse(dibh);
 510 fail_endtrans:
 511         gfs2_trans_end(sdp);
 512         if (al->al_requested) {
 513                 gfs2_inplace_release(ip);
 514                 gfs2_quota_unlock(ip);
 515                 gfs2_alloc_put(ip);
 516         }
 517         gfs2_glock_dq_m(1, &ip->i_gh);
 518         gfs2_holder_uninit(&ip->i_gh);
 519 fail_nounlock:
 520         ClearPageUptodate(page);
 521         return error;
 522 }
 523
 524 /**
 525  * gfs2_bmap - Block map function
 526  * @mapping: Address space info
 527  * @lblock: The block to map
 528  *
 529  * Returns: The disk address for the block or 0 on hole or error
 530  */
 531
 532 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 533 {
 534         struct gfs2_inode *ip = GFS2_I(mapping->host);
 535         struct gfs2_holder i_gh;
 536         sector_t dblock = 0;
 537         int error;
 538
 539         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 540         if (error)
 541                 return 0;
 542
 543         if (!gfs2_is_stuffed(ip))
 544                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 545
 546         gfs2_glock_dq_uninit(&i_gh);
 547
 548         return dblock;
 549 }
 550
 551 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 552 {
 553         struct gfs2_bufdata *bd;
 554
 555         gfs2_log_lock(sdp);
 556         bd = bh->b_private;
 557         if (bd) {
 558                 bd->bd_bh = NULL;
 559                 bh->b_private = NULL;
 560         }
 561         gfs2_log_unlock(sdp);
 562
 563         lock_buffer(bh);
 564         clear_buffer_dirty(bh);
 565         bh->b_bdev = NULL;
 566         clear_buffer_mapped(bh);
 567         clear_buffer_req(bh);
 568         clear_buffer_new(bh);
 569         clear_buffer_delay(bh);
 570         unlock_buffer(bh);
 571 }
 572
 573 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 574 {
 575         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 576         struct buffer_head *head, *bh, *next;
 577         unsigned int curr_off = 0;
 578
 579         BUG_ON(!PageLocked(page));
 580         if (!page_has_buffers(page))
 581                 return;
 582
 583         bh = head = page_buffers(page);
 584         do {
 585                 unsigned int next_off = curr_off + bh->b_size;
 586                 next = bh->b_this_page;
 587
 588                 if (offset <= curr_off)
 589                         discard_buffer(sdp, bh);
 590
 591                 curr_off = next_off;
 592                 bh = next;
 593         } while (bh != head);
 594
 595         if (!offset)
 596                 try_to_release_page(page, 0);
 597
 598         return;
 599 }
 600
 601 /**
 602  * gfs2_ok_for_dio - check that dio is valid on this file
 603  * @ip: The inode
 604  * @rw: READ or WRITE
 605  * @offset: The offset at which we are reading or writing
 606  *
 607  * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
 608  *          1 (to accept the i/o request)
 609  */
 610 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
 611 {
 612         /*
 613          * Should we return an error here? I can't see that O_DIRECT for
 614          * a journaled file makes any sense. For now we'll silently fall
 615          * back to buffered I/O, likewise we do the same for stuffed
 616          * files since they are (a) small and (b) unaligned.
 617          */
 618         if (gfs2_is_jdata(ip))
 619                 return 0;
 620
 621         if (gfs2_is_stuffed(ip))
 622                 return 0;
 623
 624         if (offset > i_size_read(&ip->i_inode))
 625                 return 0;
 626         return 1;
 627 }
 628
 629
 630
 631 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 632                               const struct iovec *iov, loff_t offset,
 633                               unsigned long nr_segs)
 634 {
 635         struct file *file = iocb->ki_filp;
 636         struct inode *inode = file->f_mapping->host;
 637         struct gfs2_inode *ip = GFS2_I(inode);
 638         struct gfs2_holder gh;
 639         int rv;
 640
 641         /*
 642          * Deferred lock, even if its a write, since we do no allocation
 643          * on this path. All we need change is atime, and this lock mode
 644          * ensures that other nodes have flushed their buffered read caches
 645          * (i.e. their page cache entries for this inode). We do not,
 646          * unfortunately have the option of only flushing a range like
 647          * the VFS does.
 648          */
 649         gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, GL_ATIME, &gh);
 650         rv = gfs2_glock_nq_atime(&gh);
 651         if (rv)
 652                 return rv;
 653         rv = gfs2_ok_for_dio(ip, rw, offset);
 654         if (rv != 1)
 655                 goto out; /* dio not valid, fall back to buffered i/o */
 656
 657         rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
 658                                            iov, offset, nr_segs,
 659                                            gfs2_get_block_direct, NULL);
 660 out:
 661         gfs2_glock_dq_m(1, &gh);
 662         gfs2_holder_uninit(&gh);
 663         return rv;
 664 }
 665
 666 /**
 667  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
 668  * @bh: the buffer we're stuck on
 669  *
 670  */
 671
 672 static void stuck_releasepage(struct buffer_head *bh)
 673 {
 674         struct inode *inode = bh->b_page->mapping->host;
 675         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 676         struct gfs2_bufdata *bd = bh->b_private;
 677         struct gfs2_glock *gl;
 678 static unsigned limit = 0;
 679
 680         if (limit > 3)
 681                 return;
 682         limit++;
 683
 684         fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
 685         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
 686                 (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
 687         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
 688         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
 689
 690         if (!bd)
 691                 return;
 692
 693         gl = bd->bd_gl;
 694
 695         fs_warn(sdp, "gl = (%u, %llu)\n",
 696                 gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 697
 698         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
 699                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
 700                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 701
 702         if (gl->gl_ops == &gfs2_inode_glops) {
 703                 struct gfs2_inode *ip = gl->gl_object;
 704                 unsigned int x;
 705
 706                 if (!ip)
 707                         return;
 708
 709                 fs_warn(sdp, "ip = %llu %llu\n",
 710                         (unsigned long long)ip->i_num.no_formal_ino,
 711                         (unsigned long long)ip->i_num.no_addr);
 712
 713                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 714                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
 715                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
 716         }
 717 }
 718
 719 /**
 720  * gfs2_releasepage - free the metadata associated with a page
 721  * @page: the page that's being released
 722  * @gfp_mask: passed from Linux VFS, ignored by us
 723  *
 724  * Call try_to_free_buffers() if the buffers in this page can be
 725  * released.
 726  *
 727  * Returns: 0
 728  */
 729
 730 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 731 {
 732         struct inode *aspace = page->mapping->host;
 733         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
 734         struct buffer_head *bh, *head;
 735         struct gfs2_bufdata *bd;
 736         unsigned long t = jiffies + gfs2_tune_get(sdp, gt_stall_secs) * HZ;
 737
 738         if (!page_has_buffers(page))
 739                 goto out;
 740
 741         head = bh = page_buffers(page);
 742         do {
 743                 while (atomic_read(&bh->b_count)) {
 744                         if (!atomic_read(&aspace->i_writecount))
 745                                 return 0;
 746
 747                         if (!(gfp_mask & __GFP_WAIT))
 748                                 return 0;
 749
 750                         if (time_after_eq(jiffies, t)) {
 751                                 stuck_releasepage(bh);
 752                                 /* should we withdraw here? */
 753                                 return 0;
 754                         }
 755
 756                         yield();
 757                 }
 758
 759                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 760                 gfs2_assert_warn(sdp, !buffer_dirty(bh));
 761
 762                 gfs2_log_lock(sdp);
 763                 bd = bh->b_private;
 764                 if (bd) {
 765                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 766                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
 767                         gfs2_assert_warn(sdp, !bd->bd_ail);
 768                         bd->bd_bh = NULL;
 769                         if (!list_empty(&bd->bd_le.le_list))
 770                                 bd = NULL;
 771                         bh->b_private = NULL;
 772                 }
 773                 gfs2_log_unlock(sdp);
 774                 if (bd)
 775                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 776
 777                 bh = bh->b_this_page;
 778         } while (bh != head);
 779
 780 out:
 781         return try_to_free_buffers(page);
 782 }
 783
 784 const struct address_space_operations gfs2_file_aops = {
 785         .writepage = gfs2_writepage,
 786         .writepages = gfs2_writepages,
 787         .readpage = gfs2_readpage,
 788         .readpages = gfs2_readpages,
 789         .sync_page = block_sync_page,
 790         .prepare_write = gfs2_prepare_write,
 791         .commit_write = gfs2_commit_write,
 792         .bmap = gfs2_bmap,
 793         .invalidatepage = gfs2_invalidatepage,
 794         .releasepage = gfs2_releasepage,
 795         .direct_IO = gfs2_direct_IO,
 796 };
 797