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 "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         uint64_t 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         uint64_t 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 /**
 122  * gfs2_writepage - Write complete page
 123  * @page: Page to write
 124  *
 125  * Returns: errno
 126  *
 127  * Some of this is copied from block_write_full_page() although we still
 128  * call it to do most of the work.
 129  */
 130
 131 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
 132 {
 133         struct inode *inode = page->mapping->host;
 134         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 135         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 136         loff_t i_size = i_size_read(inode);
 137         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
 138         unsigned offset;
 139         int error;
 140         int done_trans = 0;
 141
 142         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl))) {
 143                 unlock_page(page);
 144                 return -EIO;
 145         }
 146         if (current->journal_info)
 147                 goto out_ignore;
 148
 149         /* Is the page fully outside i_size? (truncate in progress) */
 150         offset = i_size & (PAGE_CACHE_SIZE-1);
 151         if (page->index > end_index || (page->index == end_index && !offset)) {
 152                 page->mapping->a_ops->invalidatepage(page, 0);
 153                 unlock_page(page);
 154                 return 0; /* don't care */
 155         }
 156
 157         if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED || gfs2_is_jdata(ip)) {
 158                 error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
 159                 if (error)
 160                         goto out_ignore;
 161                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
 162                 done_trans = 1;
 163         }
 164         error = block_write_full_page(page, get_block_noalloc, wbc);
 165         if (done_trans)
 166                 gfs2_trans_end(sdp);
 167         gfs2_meta_cache_flush(ip);
 168         return error;
 169
 170 out_ignore:
 171         redirty_page_for_writepage(wbc, page);
 172         unlock_page(page);
 173         return 0;
 174 }
 175
 176 static int zero_readpage(struct page *page)
 177 {
 178         void *kaddr;
 179
 180         kaddr = kmap_atomic(page, KM_USER0);
 181         memset(kaddr, 0, PAGE_CACHE_SIZE);
 182         kunmap_atomic(page, KM_USER0);
 183
 184         SetPageUptodate(page);
 185
 186         return 0;
 187 }
 188
 189 /**
 190  * stuffed_readpage - Fill in a Linux page with stuffed file data
 191  * @ip: the inode
 192  * @page: the page
 193  *
 194  * Returns: errno
 195  */
 196
 197 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 198 {
 199         struct buffer_head *dibh;
 200         void *kaddr;
 201         int error;
 202
 203         /* Only the first page of a stuffed file might contain data */
 204         if (unlikely(page->index))
 205                 return zero_readpage(page);
 206
 207         error = gfs2_meta_inode_buffer(ip, &dibh);
 208         if (error)
 209                 return error;
 210
 211         kaddr = kmap_atomic(page, KM_USER0);
 212         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
 213                ip->i_di.di_size);
 214         memset(kaddr + ip->i_di.di_size, 0, PAGE_CACHE_SIZE - ip->i_di.di_size);
 215         kunmap_atomic(page, KM_USER0);
 216
 217         brelse(dibh);
 218
 219         SetPageUptodate(page);
 220
 221         return 0;
 222 }
 223
 224
 225 /**
 226  * gfs2_readpage - readpage with locking
 227  * @file: The file to read a page for. N.B. This may be NULL if we are
 228  * reading an internal file.
 229  * @page: The page to read
 230  *
 231  * Returns: errno
 232  */
 233
 234 static int gfs2_readpage(struct file *file, struct page *page)
 235 {
 236         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 237         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 238         struct gfs2_holder gh;
 239         int error;
 240         int do_unlock = 0;
 241
 242         if (likely(file != &gfs2_internal_file_sentinal)) {
 243                 if (file) {
 244                         struct gfs2_file *gf = file->private_data;
 245                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 246                                 goto skip_lock;
 247                 }
 248                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
 249                 do_unlock = 1;
 250                 error = gfs2_glock_nq_m_atime(1, &gh);
 251                 if (unlikely(error))
 252                         goto out_unlock;
 253         }
 254
 255 skip_lock:
 256         if (gfs2_is_stuffed(ip)) {
 257                 error = stuffed_readpage(ip, page);
 258                 unlock_page(page);
 259         } else
 260                 error = mpage_readpage(page, gfs2_get_block);
 261
 262         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 263                 error = -EIO;
 264
 265         if (file != &gfs2_internal_file_sentinal) {
 266                 gfs2_glock_dq_m(1, &gh);
 267                 gfs2_holder_uninit(&gh);
 268         }
 269 out:
 270         return error;
 271 out_unlock:
 272         unlock_page(page);
 273         if (do_unlock)
 274                 gfs2_holder_uninit(&gh);
 275         goto out;
 276 }
 277
 278 /**
 279  * gfs2_readpages - Read a bunch of pages at once
 280  *
 281  * Some notes:
 282  * 1. This is only for readahead, so we can simply ignore any things
 283  *    which are slightly inconvenient (such as locking conflicts between
 284  *    the page lock and the glock) and return having done no I/O. Its
 285  *    obviously not something we'd want to do on too regular a basis.
 286  *    Any I/O we ignore at this time will be done via readpage later.
 287  * 2. We have to handle stuffed files here too.
 288  * 3. mpage_readpages() does most of the heavy lifting in the common case.
 289  * 4. gfs2_get_block() is relied upon to set BH_Boundary in the right places.
 290  * 5. We use LM_FLAG_TRY_1CB here, effectively we then have lock-ahead as
 291  *    well as read-ahead.
 292  */
 293 static int gfs2_readpages(struct file *file, struct address_space *mapping,
 294                           struct list_head *pages, unsigned nr_pages)
 295 {
 296         struct inode *inode = mapping->host;
 297         struct gfs2_inode *ip = GFS2_I(inode);
 298         struct gfs2_sbd *sdp = GFS2_SB(inode);
 299         struct gfs2_holder gh;
 300         unsigned page_idx;
 301         int ret;
 302         int do_unlock = 0;
 303
 304         if (likely(file != &gfs2_internal_file_sentinal)) {
 305                 if (file) {
 306                         struct gfs2_file *gf = file->private_data;
 307                         if (test_bit(GFF_EXLOCK, &gf->f_flags))
 308                                 goto skip_lock;
 309                 }
 310                 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
 311                                  LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
 312                 do_unlock = 1;
 313                 ret = gfs2_glock_nq_m_atime(1, &gh);
 314                 if (ret == GLR_TRYFAILED)
 315                         goto out_noerror;
 316                 if (unlikely(ret))
 317                         goto out_unlock;
 318         }
 319 skip_lock:
 320         if (gfs2_is_stuffed(ip)) {
 321                 struct pagevec lru_pvec;
 322                 pagevec_init(&lru_pvec, 0);
 323                 for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 324                         struct page *page = list_entry(pages->prev, struct page, lru);
 325                         prefetchw(&page->flags);
 326                         list_del(&page->lru);
 327                         if (!add_to_page_cache(page, mapping,
 328                                                page->index, GFP_KERNEL)) {
 329                                 ret = stuffed_readpage(ip, page);
 330                                 unlock_page(page);
 331                                 if (!pagevec_add(&lru_pvec, page))
 332                                          __pagevec_lru_add(&lru_pvec);
 333                         } else {
 334                                 page_cache_release(page);
 335                         }
 336                 }
 337                 pagevec_lru_add(&lru_pvec);
 338                 ret = 0;
 339         } else {
 340                 /* What we really want to do .... */
 341                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
 342         }
 343
 344         if (do_unlock) {
 345                 gfs2_glock_dq_m(1, &gh);
 346                 gfs2_holder_uninit(&gh);
 347         }
 348 out:
 349         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 350                 ret = -EIO;
 351         return ret;
 352 out_noerror:
 353         ret = 0;
 354 out_unlock:
 355         /* unlock all pages, we can't do any I/O right now */
 356         for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 357                 struct page *page = list_entry(pages->prev, struct page, lru);
 358                 list_del(&page->lru);
 359                 unlock_page(page);
 360                 page_cache_release(page);
 361         }
 362         if (do_unlock)
 363                 gfs2_holder_uninit(&gh);
 364         goto out;
 365 }
 366
 367 /**
 368  * gfs2_prepare_write - Prepare to write a page to a file
 369  * @file: The file to write to
 370  * @page: The page which is to be prepared for writing
 371  * @from: From (byte range within page)
 372  * @to: To (byte range within page)
 373  *
 374  * Returns: errno
 375  */
 376
 377 static int gfs2_prepare_write(struct file *file, struct page *page,
 378                               unsigned from, unsigned to)
 379 {
 380         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
 381         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
 382         unsigned int data_blocks, ind_blocks, rblocks;
 383         int alloc_required;
 384         int error = 0;
 385         loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + from;
 386         loff_t end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
 387         struct gfs2_alloc *al;
 388
 389         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
 390         error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
 391         if (error)
 392                 goto out_uninit;
 393
 394         gfs2_write_calc_reserv(ip, to - from, &data_blocks, &ind_blocks);
 395
 396         error = gfs2_write_alloc_required(ip, pos, from - to, &alloc_required);
 397         if (error)
 398                 goto out_unlock;
 399
 400
 401         if (alloc_required) {
 402                 al = gfs2_alloc_get(ip);
 403
 404                 error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
 405                 if (error)
 406                         goto out_alloc_put;
 407
 408                 error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
 409                 if (error)
 410                         goto out_qunlock;
 411
 412                 al->al_requested = data_blocks + ind_blocks;
 413                 error = gfs2_inplace_reserve(ip);
 414                 if (error)
 415                         goto out_qunlock;
 416         }
 417
 418         rblocks = RES_DINODE + ind_blocks;
 419         if (gfs2_is_jdata(ip))
 420                 rblocks += data_blocks ? data_blocks : 1;
 421         if (ind_blocks || data_blocks)
 422                 rblocks += RES_STATFS + RES_QUOTA;
 423
 424         error = gfs2_trans_begin(sdp, rblocks, 0);
 425         if (error)
 426                 goto out;
 427
 428         if (gfs2_is_stuffed(ip)) {
 429                 if (end > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
 430                         error = gfs2_unstuff_dinode(ip, page);
 431                         if (error == 0)
 432                                 goto prepare_write;
 433                 } else if (!PageUptodate(page))
 434                         error = stuffed_readpage(ip, page);
 435                 goto out;
 436         }
 437
 438 prepare_write:
 439         error = block_prepare_write(page, from, to, gfs2_get_block);
 440
 441 out:
 442         if (error) {
 443                 gfs2_trans_end(sdp);
 444                 if (alloc_required) {
 445                         gfs2_inplace_release(ip);
 446 out_qunlock:
 447                         gfs2_quota_unlock(ip);
 448 out_alloc_put:
 449                         gfs2_alloc_put(ip);
 450                 }
 451 out_unlock:
 452                 gfs2_glock_dq_m(1, &ip->i_gh);
 453 out_uninit:
 454                 gfs2_holder_uninit(&ip->i_gh);
 455         }
 456
 457         return error;
 458 }
 459
 460 /**
 461  * gfs2_commit_write - Commit write to a file
 462  * @file: The file to write to
 463  * @page: The page containing the data
 464  * @from: From (byte range within page)
 465  * @to: To (byte range within page)
 466  *
 467  * Returns: errno
 468  */
 469
 470 static int gfs2_commit_write(struct file *file, struct page *page,
 471                              unsigned from, unsigned to)
 472 {
 473         struct inode *inode = page->mapping->host;
 474         struct gfs2_inode *ip = GFS2_I(inode);
 475         struct gfs2_sbd *sdp = GFS2_SB(inode);
 476         int error = -EOPNOTSUPP;
 477         struct buffer_head *dibh;
 478         struct gfs2_alloc *al = &ip->i_alloc;;
 479
 480         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_locked_by_me(ip->i_gl)))
 481                 goto fail_nounlock;
 482
 483         error = gfs2_meta_inode_buffer(ip, &dibh);
 484         if (error)
 485                 goto fail_endtrans;
 486
 487         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
 488
 489         if (gfs2_is_stuffed(ip)) {
 490                 uint64_t file_size;
 491                 void *kaddr;
 492
 493                 file_size = ((uint64_t)page->index << PAGE_CACHE_SHIFT) + to;
 494
 495                 kaddr = kmap_atomic(page, KM_USER0);
 496                 memcpy(dibh->b_data + sizeof(struct gfs2_dinode) + from,
 497                        (char *)kaddr + from, to - from);
 498                 kunmap_atomic(page, KM_USER0);
 499
 500                 SetPageUptodate(page);
 501
 502                 if (inode->i_size < file_size)
 503                         i_size_write(inode, file_size);
 504         } else {
 505                 if (sdp->sd_args.ar_data == GFS2_DATA_ORDERED ||
 506                     gfs2_is_jdata(ip))
 507                         gfs2_page_add_databufs(ip, page, from, to);
 508                 error = generic_commit_write(file, page, from, to);
 509                 if (error)
 510                         goto fail;
 511         }
 512
 513         if (ip->i_di.di_size < inode->i_size)
 514                 ip->i_di.di_size = inode->i_size;
 515
 516         gfs2_dinode_out(&ip->i_di, dibh->b_data);
 517         brelse(dibh);
 518         gfs2_trans_end(sdp);
 519         if (al->al_requested) {
 520                 gfs2_inplace_release(ip);
 521                 gfs2_quota_unlock(ip);
 522                 gfs2_alloc_put(ip);
 523         }
 524         gfs2_glock_dq_m(1, &ip->i_gh);
 525         gfs2_holder_uninit(&ip->i_gh);
 526         return 0;
 527
 528 fail:
 529         brelse(dibh);
 530 fail_endtrans:
 531         gfs2_trans_end(sdp);
 532         if (al->al_requested) {
 533                 gfs2_inplace_release(ip);
 534                 gfs2_quota_unlock(ip);
 535                 gfs2_alloc_put(ip);
 536         }
 537         gfs2_glock_dq_m(1, &ip->i_gh);
 538         gfs2_holder_uninit(&ip->i_gh);
 539 fail_nounlock:
 540         ClearPageUptodate(page);
 541         return error;
 542 }
 543
 544 /**
 545  * gfs2_bmap - Block map function
 546  * @mapping: Address space info
 547  * @lblock: The block to map
 548  *
 549  * Returns: The disk address for the block or 0 on hole or error
 550  */
 551
 552 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 553 {
 554         struct gfs2_inode *ip = GFS2_I(mapping->host);
 555         struct gfs2_holder i_gh;
 556         sector_t dblock = 0;
 557         int error;
 558
 559         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 560         if (error)
 561                 return 0;
 562
 563         if (!gfs2_is_stuffed(ip))
 564                 dblock = generic_block_bmap(mapping, lblock, gfs2_get_block);
 565
 566         gfs2_glock_dq_uninit(&i_gh);
 567
 568         return dblock;
 569 }
 570
 571 static void discard_buffer(struct gfs2_sbd *sdp, struct buffer_head *bh)
 572 {
 573         struct gfs2_bufdata *bd;
 574
 575         gfs2_log_lock(sdp);
 576         bd = bh->b_private;
 577         if (bd) {
 578                 bd->bd_bh = NULL;
 579                 bh->b_private = NULL;
 580                 gfs2_log_unlock(sdp);
 581                 brelse(bh);
 582         } else
 583                 gfs2_log_unlock(sdp);
 584
 585         lock_buffer(bh);
 586         clear_buffer_dirty(bh);
 587         bh->b_bdev = NULL;
 588         clear_buffer_mapped(bh);
 589         clear_buffer_req(bh);
 590         clear_buffer_new(bh);
 591         clear_buffer_delay(bh);
 592         unlock_buffer(bh);
 593 }
 594
 595 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
 596 {
 597         struct gfs2_sbd *sdp = page->mapping->host->i_sb->s_fs_info;
 598         struct buffer_head *head, *bh, *next;
 599         unsigned int curr_off = 0;
 600
 601         BUG_ON(!PageLocked(page));
 602         if (!page_has_buffers(page))
 603                 return;
 604
 605         bh = head = page_buffers(page);
 606         do {
 607                 unsigned int next_off = curr_off + bh->b_size;
 608                 next = bh->b_this_page;
 609
 610                 if (offset <= curr_off)
 611                         discard_buffer(sdp, bh);
 612
 613                 curr_off = next_off;
 614                 bh = next;
 615         } while (bh != head);
 616
 617         if (!offset)
 618                 try_to_release_page(page, 0);
 619
 620         return;
 621 }
 622
 623 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
 624                               const struct iovec *iov, loff_t offset,
 625                               unsigned long nr_segs)
 626 {
 627         struct file *file = iocb->ki_filp;
 628         struct inode *inode = file->f_mapping->host;
 629         struct gfs2_inode *ip = GFS2_I(inode);
 630         struct gfs2_holder gh;
 631         int rv;
 632
 633         if (rw == READ)
 634                 mutex_lock(&inode->i_mutex);
 635         /*
 636          * Shared lock, even if its a write, since we do no allocation
 637          * on this path. All we need change is atime.
 638          */
 639         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 640         rv = gfs2_glock_nq_m_atime(1, &gh);
 641         if (rv)
 642                 goto out;
 643
 644         if (offset > i_size_read(inode))
 645                 goto out;
 646
 647         /*
 648          * Should we return an error here? I can't see that O_DIRECT for
 649          * a journaled file makes any sense. For now we'll silently fall
 650          * back to buffered I/O, likewise we do the same for stuffed
 651          * files since they are (a) small and (b) unaligned.
 652          */
 653         if (gfs2_is_jdata(ip))
 654                 goto out;
 655
 656         if (gfs2_is_stuffed(ip))
 657                 goto out;
 658
 659         rv = blockdev_direct_IO_own_locking(rw, iocb, inode,
 660                                             inode->i_sb->s_bdev,
 661                                             iov, offset, nr_segs,
 662                                             gfs2_get_block, NULL);
 663 out:
 664         gfs2_glock_dq_m(1, &gh);
 665         gfs2_holder_uninit(&gh);
 666         if (rw == READ)
 667                 mutex_unlock(&inode->i_mutex);
 668
 669         return rv;
 670 }
 671
 672 /**
 673  * stuck_releasepage - We're stuck in gfs2_releasepage().  Print stuff out.
 674  * @bh: the buffer we're stuck on
 675  *
 676  */
 677
 678 static void stuck_releasepage(struct buffer_head *bh)
 679 {
 680         struct inode *inode = bh->b_page->mapping->host;
 681         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 682         struct gfs2_bufdata *bd = bh->b_private;
 683         struct gfs2_glock *gl;
 684
 685         fs_warn(sdp, "stuck in gfs2_releasepage() %p\n", inode);
 686         fs_warn(sdp, "blkno = %llu, bh->b_count = %d\n",
 687                 (unsigned long long)bh->b_blocknr, atomic_read(&bh->b_count));
 688         fs_warn(sdp, "pinned = %u\n", buffer_pinned(bh));
 689         fs_warn(sdp, "bh->b_private = %s\n", (bd) ? "!NULL" : "NULL");
 690
 691         if (!bd)
 692                 return;
 693
 694         gl = bd->bd_gl;
 695
 696         fs_warn(sdp, "gl = (%u, %llu)\n",
 697                 gl->gl_name.ln_type, (unsigned long long)gl->gl_name.ln_number);
 698
 699         fs_warn(sdp, "bd_list_tr = %s, bd_le.le_list = %s\n",
 700                 (list_empty(&bd->bd_list_tr)) ? "no" : "yes",
 701                 (list_empty(&bd->bd_le.le_list)) ? "no" : "yes");
 702
 703         if (gl->gl_ops == &gfs2_inode_glops) {
 704                 struct gfs2_inode *ip = gl->gl_object;
 705                 unsigned int x;
 706
 707                 if (!ip)
 708                         return;
 709
 710                 fs_warn(sdp, "ip = %llu %llu\n",
 711                         (unsigned long long)ip->i_num.no_formal_ino,
 712                         (unsigned long long)ip->i_num.no_addr);
 713
 714                 for (x = 0; x < GFS2_MAX_META_HEIGHT; x++)
 715                         fs_warn(sdp, "ip->i_cache[%u] = %s\n",
 716                                 x, (ip->i_cache[x]) ? "!NULL" : "NULL");
 717         }
 718 }
 719
 720 /**
 721  * gfs2_aspace_releasepage - free the metadata associated with a page
 722  * @page: the page that's being released
 723  * @gfp_mask: passed from Linux VFS, ignored by us
 724  *
 725  * Call try_to_free_buffers() if the buffers in this page can be
 726  * released.
 727  *
 728  * Returns: 0
 729  */
 730
 731 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
 732 {
 733         struct inode *aspace = page->mapping->host;
 734         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
 735         struct buffer_head *bh, *head;
 736         struct gfs2_bufdata *bd;
 737         unsigned long t;
 738
 739         if (!page_has_buffers(page))
 740                 goto out;
 741
 742         head = bh = page_buffers(page);
 743         do {
 744                 t = jiffies;
 745
 746                 while (atomic_read(&bh->b_count)) {
 747                         if (atomic_read(&aspace->i_writecount)) {
 748                                 if (time_after_eq(jiffies, t +
 749                                     gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
 750                                         stuck_releasepage(bh);
 751                                         t = jiffies;
 752                                 }
 753
 754                                 yield();
 755                                 continue;
 756                         }
 757
 758                         return 0;
 759                 }
 760
 761                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
 762
 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, list_empty(&bd->bd_le.le_list));
 768                         gfs2_assert_warn(sdp, !bd->bd_ail);
 769                         kmem_cache_free(gfs2_bufdata_cachep, bd);
 770                         bh->b_private = NULL;
 771                 }
 772
 773                 bh = bh->b_this_page;
 774         }
 775         while (bh != head);
 776
 777 out:
 778         return try_to_free_buffers(page);
 779 }
 780
 781 const struct address_space_operations gfs2_file_aops = {
 782         .writepage = gfs2_writepage,
 783         .readpage = gfs2_readpage,
 784         .readpages = gfs2_readpages,
 785         .sync_page = block_sync_page,
 786         .prepare_write = gfs2_prepare_write,
 787         .commit_write = gfs2_commit_write,
 788         .bmap = gfs2_bmap,
 789         .invalidatepage = gfs2_invalidatepage,
 790         .releasepage = gfs2_releasepage,
 791         .direct_IO = gfs2_direct_IO,
 792 };
 793