fs/gfs2/aops.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   4  * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
   5  */
   6
   7 #include <linux/sched.h>
   8 #include <linux/slab.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/completion.h>
  11 #include <linux/buffer_head.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/pagevec.h>
  14 #include <linux/mpage.h>
  15 #include <linux/fs.h>
  16 #include <linux/writeback.h>
  17 #include <linux/swap.h>
  18 #include <linux/gfs2_ondisk.h>
  19 #include <linux/backing-dev.h>
  20 #include <linux/uio.h>
  21 #include <trace/events/writeback.h>
  22 #include <linux/sched/signal.h>
  23
  24 #include "gfs2.h"
  25 #include "incore.h"
  26 #include "bmap.h"
  27 #include "glock.h"
  28 #include "inode.h"
  29 #include "log.h"
  30 #include "meta_io.h"
  31 #include "quota.h"
  32 #include "trans.h"
  33 #include "rgrp.h"
  34 #include "super.h"
  35 #include "util.h"
  36 #include "glops.h"
  37 #include "aops.h"
  38
  39
  40 void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
  41                             unsigned int from, unsigned int len)
  42 {
  43         struct buffer_head *head = page_buffers(page);
  44         unsigned int bsize = head->b_size;
  45         struct buffer_head *bh;
  46         unsigned int to = from + len;
  47         unsigned int start, end;
  48
  49         for (bh = head, start = 0; bh != head || !start;
  50              bh = bh->b_this_page, start = end) {
  51                 end = start + bsize;
  52                 if (end <= from)
  53                         continue;
  54                 if (start >= to)
  55                         break;
  56                 set_buffer_uptodate(bh);
  57                 gfs2_trans_add_data(ip->i_gl, bh);
  58         }
  59 }
  60
  61 /**
  62  * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
  63  * @inode: The inode
  64  * @lblock: The block number to look up
  65  * @bh_result: The buffer head to return the result in
  66  * @create: Non-zero if we may add block to the file
  67  *
  68  * Returns: errno
  69  */
  70
  71 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
  72                                   struct buffer_head *bh_result, int create)
  73 {
  74         int error;
  75
  76         error = gfs2_block_map(inode, lblock, bh_result, 0);
  77         if (error)
  78                 return error;
  79         if (!buffer_mapped(bh_result))
  80                 return -ENODATA;
  81         return 0;
  82 }
  83
  84 /**
  85  * gfs2_write_jdata_page - gfs2 jdata-specific version of block_write_full_page
  86  * @page: The page to write
  87  * @wbc: The writeback control
  88  *
  89  * This is the same as calling block_write_full_page, but it also
  90  * writes pages outside of i_size
  91  */
  92 static int gfs2_write_jdata_page(struct page *page,
  93                                  struct writeback_control *wbc)
  94 {
  95         struct inode * const inode = page->mapping->host;
  96         loff_t i_size = i_size_read(inode);
  97         const pgoff_t end_index = i_size >> PAGE_SHIFT;
  98         unsigned offset;
  99
 100         /*
 101          * The page straddles i_size.  It must be zeroed out on each and every
 102          * writepage invocation because it may be mmapped.  "A file is mapped
 103          * in multiples of the page size.  For a file that is not a multiple of
 104          * the  page size, the remaining memory is zeroed when mapped, and
 105          * writes to that region are not written out to the file."
 106          */
 107         offset = i_size & (PAGE_SIZE - 1);
 108         if (page->index == end_index && offset)
 109                 zero_user_segment(page, offset, PAGE_SIZE);
 110
 111         return __block_write_full_page(inode, page, gfs2_get_block_noalloc, wbc,
 112                                        end_buffer_async_write);
 113 }
 114
 115 /**
 116  * __gfs2_jdata_writepage - The core of jdata writepage
 117  * @page: The page to write
 118  * @wbc: The writeback control
 119  *
 120  * This is shared between writepage and writepages and implements the
 121  * core of the writepage operation. If a transaction is required then
 122  * PageChecked will have been set and the transaction will have
 123  * already been started before this is called.
 124  */
 125
 126 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
 127 {
 128         struct inode *inode = page->mapping->host;
 129         struct gfs2_inode *ip = GFS2_I(inode);
 130         struct gfs2_sbd *sdp = GFS2_SB(inode);
 131
 132         if (PageChecked(page)) {
 133                 ClearPageChecked(page);
 134                 if (!page_has_buffers(page)) {
 135                         create_empty_buffers(page, inode->i_sb->s_blocksize,
 136                                              BIT(BH_Dirty)|BIT(BH_Uptodate));
 137                 }
 138                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize);
 139         }
 140         return gfs2_write_jdata_page(page, wbc);
 141 }
 142
 143 /**
 144  * gfs2_jdata_writepage - Write complete page
 145  * @page: Page to write
 146  * @wbc: The writeback control
 147  *
 148  * Returns: errno
 149  *
 150  */
 151
 152 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
 153 {
 154         struct inode *inode = page->mapping->host;
 155         struct gfs2_inode *ip = GFS2_I(inode);
 156         struct gfs2_sbd *sdp = GFS2_SB(inode);
 157
 158         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
 159                 goto out;
 160         if (PageChecked(page) || current->journal_info)
 161                 goto out_ignore;
 162         return __gfs2_jdata_writepage(page, wbc);
 163
 164 out_ignore:
 165         redirty_page_for_writepage(wbc, page);
 166 out:
 167         unlock_page(page);
 168         return 0;
 169 }
 170
 171 /**
 172  * gfs2_writepages - Write a bunch of dirty pages back to disk
 173  * @mapping: The mapping to write
 174  * @wbc: Write-back control
 175  *
 176  * Used for both ordered and writeback modes.
 177  */
 178 static int gfs2_writepages(struct address_space *mapping,
 179                            struct writeback_control *wbc)
 180 {
 181         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
 182         struct iomap_writepage_ctx wpc = { };
 183         int ret;
 184
 185         /*
 186          * Even if we didn't write any pages here, we might still be holding
 187          * dirty pages in the ail. We forcibly flush the ail because we don't
 188          * want balance_dirty_pages() to loop indefinitely trying to write out
 189          * pages held in the ail that it can't find.
 190          */
 191         ret = iomap_writepages(mapping, wbc, &wpc, &gfs2_writeback_ops);
 192         if (ret == 0)
 193                 set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
 194         return ret;
 195 }
 196
 197 /**
 198  * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
 199  * @mapping: The mapping
 200  * @wbc: The writeback control
 201  * @pvec: The vector of pages
 202  * @nr_pages: The number of pages to write
 203  * @done_index: Page index
 204  *
 205  * Returns: non-zero if loop should terminate, zero otherwise
 206  */
 207
 208 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
 209                                     struct writeback_control *wbc,
 210                                     struct pagevec *pvec,
 211                                     int nr_pages,
 212                                     pgoff_t *done_index)
 213 {
 214         struct inode *inode = mapping->host;
 215         struct gfs2_sbd *sdp = GFS2_SB(inode);
 216         unsigned nrblocks = nr_pages * (PAGE_SIZE >> inode->i_blkbits);
 217         int i;
 218         int ret;
 219
 220         ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
 221         if (ret < 0)
 222                 return ret;
 223
 224         for(i = 0; i < nr_pages; i++) {
 225                 struct page *page = pvec->pages[i];
 226
 227                 *done_index = page->index;
 228
 229                 lock_page(page);
 230
 231                 if (unlikely(page->mapping != mapping)) {
 232 continue_unlock:
 233                         unlock_page(page);
 234                         continue;
 235                 }
 236
 237                 if (!PageDirty(page)) {
 238                         /* someone wrote it for us */
 239                         goto continue_unlock;
 240                 }
 241
 242                 if (PageWriteback(page)) {
 243                         if (wbc->sync_mode != WB_SYNC_NONE)
 244                                 wait_on_page_writeback(page);
 245                         else
 246                                 goto continue_unlock;
 247                 }
 248
 249                 BUG_ON(PageWriteback(page));
 250                 if (!clear_page_dirty_for_io(page))
 251                         goto continue_unlock;
 252
 253                 trace_wbc_writepage(wbc, inode_to_bdi(inode));
 254
 255                 ret = __gfs2_jdata_writepage(page, wbc);
 256                 if (unlikely(ret)) {
 257                         if (ret == AOP_WRITEPAGE_ACTIVATE) {
 258                                 unlock_page(page);
 259                                 ret = 0;
 260                         } else {
 261
 262                                 /*
 263                                  * done_index is set past this page,
 264                                  * so media errors will not choke
 265                                  * background writeout for the entire
 266                                  * file. This has consequences for
 267                                  * range_cyclic semantics (ie. it may
 268                                  * not be suitable for data integrity
 269                                  * writeout).
 270                                  */
 271                                 *done_index = page->index + 1;
 272                                 ret = 1;
 273                                 break;
 274                         }
 275                 }
 276
 277                 /*
 278                  * We stop writing back only if we are not doing
 279                  * integrity sync. In case of integrity sync we have to
 280                  * keep going until we have written all the pages
 281                  * we tagged for writeback prior to entering this loop.
 282                  */
 283                 if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) {
 284                         ret = 1;
 285                         break;
 286                 }
 287
 288         }
 289         gfs2_trans_end(sdp);
 290         return ret;
 291 }
 292
 293 /**
 294  * gfs2_write_cache_jdata - Like write_cache_pages but different
 295  * @mapping: The mapping to write
 296  * @wbc: The writeback control
 297  *
 298  * The reason that we use our own function here is that we need to
 299  * start transactions before we grab page locks. This allows us
 300  * to get the ordering right.
 301  */
 302
 303 static int gfs2_write_cache_jdata(struct address_space *mapping,
 304                                   struct writeback_control *wbc)
 305 {
 306         int ret = 0;
 307         int done = 0;
 308         struct pagevec pvec;
 309         int nr_pages;
 310         pgoff_t writeback_index;
 311         pgoff_t index;
 312         pgoff_t end;
 313         pgoff_t done_index;
 314         int cycled;
 315         int range_whole = 0;
 316         xa_mark_t tag;
 317
 318         pagevec_init(&pvec);
 319         if (wbc->range_cyclic) {
 320                 writeback_index = mapping->writeback_index; /* prev offset */
 321                 index = writeback_index;
 322                 if (index == 0)
 323                         cycled = 1;
 324                 else
 325                         cycled = 0;
 326                 end = -1;
 327         } else {
 328                 index = wbc->range_start >> PAGE_SHIFT;
 329                 end = wbc->range_end >> PAGE_SHIFT;
 330                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
 331                         range_whole = 1;
 332                 cycled = 1; /* ignore range_cyclic tests */
 333         }
 334         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
 335                 tag = PAGECACHE_TAG_TOWRITE;
 336         else
 337                 tag = PAGECACHE_TAG_DIRTY;
 338
 339 retry:
 340         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
 341                 tag_pages_for_writeback(mapping, index, end);
 342         done_index = index;
 343         while (!done && (index <= end)) {
 344                 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
 345                                 tag);
 346                 if (nr_pages == 0)
 347                         break;
 348
 349                 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, &done_index);
 350                 if (ret)
 351                         done = 1;
 352                 if (ret > 0)
 353                         ret = 0;
 354                 pagevec_release(&pvec);
 355                 cond_resched();
 356         }
 357
 358         if (!cycled && !done) {
 359                 /*
 360                  * range_cyclic:
 361                  * We hit the last page and there is more work to be done: wrap
 362                  * back to the start of the file
 363                  */
 364                 cycled = 1;
 365                 index = 0;
 366                 end = writeback_index - 1;
 367                 goto retry;
 368         }
 369
 370         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 371                 mapping->writeback_index = done_index;
 372
 373         return ret;
 374 }
 375
 376
 377 /**
 378  * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
 379  * @mapping: The mapping to write
 380  * @wbc: The writeback control
 381  *
 382  */
 383
 384 static int gfs2_jdata_writepages(struct address_space *mapping,
 385                                  struct writeback_control *wbc)
 386 {
 387         struct gfs2_inode *ip = GFS2_I(mapping->host);
 388         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
 389         int ret;
 390
 391         ret = gfs2_write_cache_jdata(mapping, wbc);
 392         if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
 393                 gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
 394                                GFS2_LFC_JDATA_WPAGES);
 395                 ret = gfs2_write_cache_jdata(mapping, wbc);
 396         }
 397         return ret;
 398 }
 399
 400 /**
 401  * stuffed_readpage - Fill in a Linux page with stuffed file data
 402  * @ip: the inode
 403  * @page: the page
 404  *
 405  * Returns: errno
 406  */
 407 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
 408 {
 409         struct buffer_head *dibh;
 410         u64 dsize = i_size_read(&ip->i_inode);
 411         void *kaddr;
 412         int error;
 413
 414         /*
 415          * Due to the order of unstuffing files and ->fault(), we can be
 416          * asked for a zero page in the case of a stuffed file being extended,
 417          * so we need to supply one here. It doesn't happen often.
 418          */
 419         if (unlikely(page->index)) {
 420                 zero_user(page, 0, PAGE_SIZE);
 421                 SetPageUptodate(page);
 422                 return 0;
 423         }
 424
 425         error = gfs2_meta_inode_buffer(ip, &dibh);
 426         if (error)
 427                 return error;
 428
 429         kaddr = kmap_atomic(page);
 430         if (dsize > gfs2_max_stuffed_size(ip))
 431                 dsize = gfs2_max_stuffed_size(ip);
 432         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
 433         memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
 434         kunmap_atomic(kaddr);
 435         flush_dcache_page(page);
 436         brelse(dibh);
 437         SetPageUptodate(page);
 438
 439         return 0;
 440 }
 441
 442 /**
 443  * gfs2_read_folio - read a folio from a file
 444  * @file: The file to read
 445  * @folio: The folio in the file
 446  */
 447 static int gfs2_read_folio(struct file *file, struct folio *folio)
 448 {
 449         struct inode *inode = folio->mapping->host;
 450         struct gfs2_inode *ip = GFS2_I(inode);
 451         struct gfs2_sbd *sdp = GFS2_SB(inode);
 452         int error;
 453
 454         if (!gfs2_is_jdata(ip) ||
 455             (i_blocksize(inode) == PAGE_SIZE && !folio_buffers(folio))) {
 456                 error = iomap_read_folio(folio, &gfs2_iomap_ops);
 457         } else if (gfs2_is_stuffed(ip)) {
 458                 error = stuffed_readpage(ip, &folio->page);
 459                 folio_unlock(folio);
 460         } else {
 461                 error = mpage_read_folio(folio, gfs2_block_map);
 462         }
 463
 464         if (unlikely(gfs2_withdrawn(sdp)))
 465                 return -EIO;
 466
 467         return error;
 468 }
 469
 470 /**
 471  * gfs2_internal_read - read an internal file
 472  * @ip: The gfs2 inode
 473  * @buf: The buffer to fill
 474  * @pos: The file position
 475  * @size: The amount to read
 476  *
 477  */
 478
 479 int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
 480                        unsigned size)
 481 {
 482         struct address_space *mapping = ip->i_inode.i_mapping;
 483         unsigned long index = *pos >> PAGE_SHIFT;
 484         unsigned offset = *pos & (PAGE_SIZE - 1);
 485         unsigned copied = 0;
 486         unsigned amt;
 487         struct page *page;
 488         void *p;
 489
 490         do {
 491                 amt = size - copied;
 492                 if (offset + size > PAGE_SIZE)
 493                         amt = PAGE_SIZE - offset;
 494                 page = read_cache_page(mapping, index, gfs2_read_folio, NULL);
 495                 if (IS_ERR(page))
 496                         return PTR_ERR(page);
 497                 p = kmap_atomic(page);
 498                 memcpy(buf + copied, p + offset, amt);
 499                 kunmap_atomic(p);
 500                 put_page(page);
 501                 copied += amt;
 502                 index++;
 503                 offset = 0;
 504         } while(copied < size);
 505         (*pos) += size;
 506         return size;
 507 }
 508
 509 /**
 510  * gfs2_readahead - Read a bunch of pages at once
 511  * @rac: Read-ahead control structure
 512  *
 513  * Some notes:
 514  * 1. This is only for readahead, so we can simply ignore any things
 515  *    which are slightly inconvenient (such as locking conflicts between
 516  *    the page lock and the glock) and return having done no I/O. Its
 517  *    obviously not something we'd want to do on too regular a basis.
 518  *    Any I/O we ignore at this time will be done via readpage later.
 519  * 2. We don't handle stuffed files here we let readpage do the honours.
 520  * 3. mpage_readahead() does most of the heavy lifting in the common case.
 521  * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
 522  */
 523
 524 static void gfs2_readahead(struct readahead_control *rac)
 525 {
 526         struct inode *inode = rac->mapping->host;
 527         struct gfs2_inode *ip = GFS2_I(inode);
 528
 529         if (gfs2_is_stuffed(ip))
 530                 ;
 531         else if (gfs2_is_jdata(ip))
 532                 mpage_readahead(rac, gfs2_block_map);
 533         else
 534                 iomap_readahead(rac, &gfs2_iomap_ops);
 535 }
 536
 537 /**
 538  * adjust_fs_space - Adjusts the free space available due to gfs2_grow
 539  * @inode: the rindex inode
 540  */
 541 void adjust_fs_space(struct inode *inode)
 542 {
 543         struct gfs2_sbd *sdp = GFS2_SB(inode);
 544         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
 545         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
 546         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
 547         struct buffer_head *m_bh;
 548         u64 fs_total, new_free;
 549
 550         if (gfs2_trans_begin(sdp, 2 * RES_STATFS, 0) != 0)
 551                 return;
 552
 553         /* Total up the file system space, according to the latest rindex. */
 554         fs_total = gfs2_ri_total(sdp);
 555         if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
 556                 goto out;
 557
 558         spin_lock(&sdp->sd_statfs_spin);
 559         gfs2_statfs_change_in(m_sc, m_bh->b_data +
 560                               sizeof(struct gfs2_dinode));
 561         if (fs_total > (m_sc->sc_total + l_sc->sc_total))
 562                 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
 563         else
 564                 new_free = 0;
 565         spin_unlock(&sdp->sd_statfs_spin);
 566         fs_warn(sdp, "File system extended by %llu blocks.\n",
 567                 (unsigned long long)new_free);
 568         gfs2_statfs_change(sdp, new_free, new_free, 0);
 569
 570         update_statfs(sdp, m_bh);
 571         brelse(m_bh);
 572 out:
 573         sdp->sd_rindex_uptodate = 0;
 574         gfs2_trans_end(sdp);
 575 }
 576
 577 static bool jdata_dirty_folio(struct address_space *mapping,
 578                 struct folio *folio)
 579 {
 580         if (current->journal_info)
 581                 folio_set_checked(folio);
 582         return block_dirty_folio(mapping, folio);
 583 }
 584
 585 /**
 586  * gfs2_bmap - Block map function
 587  * @mapping: Address space info
 588  * @lblock: The block to map
 589  *
 590  * Returns: The disk address for the block or 0 on hole or error
 591  */
 592
 593 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
 594 {
 595         struct gfs2_inode *ip = GFS2_I(mapping->host);
 596         struct gfs2_holder i_gh;
 597         sector_t dblock = 0;
 598         int error;
 599
 600         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
 601         if (error)
 602                 return 0;
 603
 604         if (!gfs2_is_stuffed(ip))
 605                 dblock = iomap_bmap(mapping, lblock, &gfs2_iomap_ops);
 606
 607         gfs2_glock_dq_uninit(&i_gh);
 608
 609         return dblock;
 610 }
 611
 612 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
 613 {
 614         struct gfs2_bufdata *bd;
 615
 616         lock_buffer(bh);
 617         gfs2_log_lock(sdp);
 618         clear_buffer_dirty(bh);
 619         bd = bh->b_private;
 620         if (bd) {
 621                 if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
 622                         list_del_init(&bd->bd_list);
 623                 else {
 624                         spin_lock(&sdp->sd_ail_lock);
 625                         gfs2_remove_from_journal(bh, REMOVE_JDATA);
 626                         spin_unlock(&sdp->sd_ail_lock);
 627                 }
 628         }
 629         bh->b_bdev = NULL;
 630         clear_buffer_mapped(bh);
 631         clear_buffer_req(bh);
 632         clear_buffer_new(bh);
 633         gfs2_log_unlock(sdp);
 634         unlock_buffer(bh);
 635 }
 636
 637 static void gfs2_invalidate_folio(struct folio *folio, size_t offset,
 638                                 size_t length)
 639 {
 640         struct gfs2_sbd *sdp = GFS2_SB(folio->mapping->host);
 641         size_t stop = offset + length;
 642         int partial_page = (offset || length < folio_size(folio));
 643         struct buffer_head *bh, *head;
 644         unsigned long pos = 0;
 645
 646         BUG_ON(!folio_test_locked(folio));
 647         if (!partial_page)
 648                 folio_clear_checked(folio);
 649         head = folio_buffers(folio);
 650         if (!head)
 651                 goto out;
 652
 653         bh = head;
 654         do {
 655                 if (pos + bh->b_size > stop)
 656                         return;
 657
 658                 if (offset <= pos)
 659                         gfs2_discard(sdp, bh);
 660                 pos += bh->b_size;
 661                 bh = bh->b_this_page;
 662         } while (bh != head);
 663 out:
 664         if (!partial_page)
 665                 filemap_release_folio(folio, 0);
 666 }
 667
 668 /**
 669  * gfs2_release_folio - free the metadata associated with a folio
 670  * @folio: the folio that's being released
 671  * @gfp_mask: passed from Linux VFS, ignored by us
 672  *
 673  * Calls try_to_free_buffers() to free the buffers and put the folio if the
 674  * buffers can be released.
 675  *
 676  * Returns: true if the folio was put or else false
 677  */
 678
 679 bool gfs2_release_folio(struct folio *folio, gfp_t gfp_mask)
 680 {
 681         struct address_space *mapping = folio->mapping;
 682         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
 683         struct buffer_head *bh, *head;
 684         struct gfs2_bufdata *bd;
 685
 686         head = folio_buffers(folio);
 687         if (!head)
 688                 return false;
 689
 690         /*
 691          * mm accommodates an old ext3 case where clean folios might
 692          * not have had the dirty bit cleared.  Thus, it can send actual
 693          * dirty folios to ->release_folio() via shrink_active_list().
 694          *
 695          * As a workaround, we skip folios that contain dirty buffers
 696          * below.  Once ->release_folio isn't called on dirty folios
 697          * anymore, we can warn on dirty buffers like we used to here
 698          * again.
 699          */
 700
 701         gfs2_log_lock(sdp);
 702         bh = head;
 703         do {
 704                 if (atomic_read(&bh->b_count))
 705                         goto cannot_release;
 706                 bd = bh->b_private;
 707                 if (bd && bd->bd_tr)
 708                         goto cannot_release;
 709                 if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh)))
 710                         goto cannot_release;
 711                 bh = bh->b_this_page;
 712         } while (bh != head);
 713
 714         bh = head;
 715         do {
 716                 bd = bh->b_private;
 717                 if (bd) {
 718                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
 719                         bd->bd_bh = NULL;
 720                         bh->b_private = NULL;
 721                         /*
 722                          * The bd may still be queued as a revoke, in which
 723                          * case we must not dequeue nor free it.
 724                          */
 725                         if (!bd->bd_blkno && !list_empty(&bd->bd_list))
 726                                 list_del_init(&bd->bd_list);
 727                         if (list_empty(&bd->bd_list))
 728                                 kmem_cache_free(gfs2_bufdata_cachep, bd);
 729                 }
 730
 731                 bh = bh->b_this_page;
 732         } while (bh != head);
 733         gfs2_log_unlock(sdp);
 734
 735         return try_to_free_buffers(folio);
 736
 737 cannot_release:
 738         gfs2_log_unlock(sdp);
 739         return false;
 740 }
 741
 742 static const struct address_space_operations gfs2_aops = {
 743         .writepages = gfs2_writepages,
 744         .read_folio = gfs2_read_folio,
 745         .readahead = gfs2_readahead,
 746         .dirty_folio = filemap_dirty_folio,
 747         .release_folio = iomap_release_folio,
 748         .invalidate_folio = iomap_invalidate_folio,
 749         .bmap = gfs2_bmap,
 750         .direct_IO = noop_direct_IO,
 751         .migrate_folio = filemap_migrate_folio,
 752         .is_partially_uptodate = iomap_is_partially_uptodate,
 753         .error_remove_page = generic_error_remove_page,
 754 };
 755
 756 static const struct address_space_operations gfs2_jdata_aops = {
 757         .writepage = gfs2_jdata_writepage,
 758         .writepages = gfs2_jdata_writepages,
 759         .read_folio = gfs2_read_folio,
 760         .readahead = gfs2_readahead,
 761         .dirty_folio = jdata_dirty_folio,
 762         .bmap = gfs2_bmap,
 763         .invalidate_folio = gfs2_invalidate_folio,
 764         .release_folio = gfs2_release_folio,
 765         .is_partially_uptodate = block_is_partially_uptodate,
 766         .error_remove_page = generic_error_remove_page,
 767 };
 768
 769 void gfs2_set_aops(struct inode *inode)
 770 {
 771         if (gfs2_is_jdata(GFS2_I(inode)))
 772                 inode->i_mapping->a_ops = &gfs2_jdata_aops;
 773         else
 774                 inode->i_mapping->a_ops = &gfs2_aops;
 775 }