Merge branch 'for-5.7/appleir' into for-linus
[linux-2.6-microblaze.git] / 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 -EIO;
81         return 0;
82 }
83
84 /**
85  * gfs2_writepage - Write page for writeback mappings
86  * @page: The page
87  * @wbc: The writeback control
88  */
89 static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
90 {
91         struct inode *inode = page->mapping->host;
92         struct gfs2_inode *ip = GFS2_I(inode);
93         struct gfs2_sbd *sdp = GFS2_SB(inode);
94         loff_t i_size = i_size_read(inode);
95         pgoff_t end_index = i_size >> PAGE_SHIFT;
96         unsigned offset;
97
98         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
99                 goto out;
100         if (current->journal_info)
101                 goto redirty;
102         /* Is the page fully outside i_size? (truncate in progress) */
103         offset = i_size & (PAGE_SIZE-1);
104         if (page->index > end_index || (page->index == end_index && !offset)) {
105                 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
106                 goto out;
107         }
108
109         return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
110
111 redirty:
112         redirty_page_for_writepage(wbc, page);
113 out:
114         unlock_page(page);
115         return 0;
116 }
117
118 /* This is the same as calling block_write_full_page, but it also
119  * writes pages outside of i_size
120  */
121 static int gfs2_write_full_page(struct page *page, get_block_t *get_block,
122                                 struct writeback_control *wbc)
123 {
124         struct inode * const inode = page->mapping->host;
125         loff_t i_size = i_size_read(inode);
126         const pgoff_t end_index = i_size >> PAGE_SHIFT;
127         unsigned offset;
128
129         /*
130          * The page straddles i_size.  It must be zeroed out on each and every
131          * writepage invocation because it may be mmapped.  "A file is mapped
132          * in multiples of the page size.  For a file that is not a multiple of
133          * the  page size, the remaining memory is zeroed when mapped, and
134          * writes to that region are not written out to the file."
135          */
136         offset = i_size & (PAGE_SIZE - 1);
137         if (page->index == end_index && offset)
138                 zero_user_segment(page, offset, PAGE_SIZE);
139
140         return __block_write_full_page(inode, page, get_block, wbc,
141                                        end_buffer_async_write);
142 }
143
144 /**
145  * __gfs2_jdata_writepage - The core of jdata writepage
146  * @page: The page to write
147  * @wbc: The writeback control
148  *
149  * This is shared between writepage and writepages and implements the
150  * core of the writepage operation. If a transaction is required then
151  * PageChecked will have been set and the transaction will have
152  * already been started before this is called.
153  */
154
155 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
156 {
157         struct inode *inode = page->mapping->host;
158         struct gfs2_inode *ip = GFS2_I(inode);
159         struct gfs2_sbd *sdp = GFS2_SB(inode);
160
161         if (PageChecked(page)) {
162                 ClearPageChecked(page);
163                 if (!page_has_buffers(page)) {
164                         create_empty_buffers(page, inode->i_sb->s_blocksize,
165                                              BIT(BH_Dirty)|BIT(BH_Uptodate));
166                 }
167                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize);
168         }
169         return gfs2_write_full_page(page, gfs2_get_block_noalloc, wbc);
170 }
171
172 /**
173  * gfs2_jdata_writepage - Write complete page
174  * @page: Page to write
175  * @wbc: The writeback control
176  *
177  * Returns: errno
178  *
179  */
180
181 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
182 {
183         struct inode *inode = page->mapping->host;
184         struct gfs2_inode *ip = GFS2_I(inode);
185         struct gfs2_sbd *sdp = GFS2_SB(inode);
186
187         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
188                 goto out;
189         if (PageChecked(page) || current->journal_info)
190                 goto out_ignore;
191         return __gfs2_jdata_writepage(page, wbc);
192
193 out_ignore:
194         redirty_page_for_writepage(wbc, page);
195 out:
196         unlock_page(page);
197         return 0;
198 }
199
200 /**
201  * gfs2_writepages - Write a bunch of dirty pages back to disk
202  * @mapping: The mapping to write
203  * @wbc: Write-back control
204  *
205  * Used for both ordered and writeback modes.
206  */
207 static int gfs2_writepages(struct address_space *mapping,
208                            struct writeback_control *wbc)
209 {
210         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
211         int ret = mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
212
213         /*
214          * Even if we didn't write any pages here, we might still be holding
215          * dirty pages in the ail. We forcibly flush the ail because we don't
216          * want balance_dirty_pages() to loop indefinitely trying to write out
217          * pages held in the ail that it can't find.
218          */
219         if (ret == 0)
220                 set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
221
222         return ret;
223 }
224
225 /**
226  * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
227  * @mapping: The mapping
228  * @wbc: The writeback control
229  * @pvec: The vector of pages
230  * @nr_pages: The number of pages to write
231  * @done_index: Page index
232  *
233  * Returns: non-zero if loop should terminate, zero otherwise
234  */
235
236 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
237                                     struct writeback_control *wbc,
238                                     struct pagevec *pvec,
239                                     int nr_pages,
240                                     pgoff_t *done_index)
241 {
242         struct inode *inode = mapping->host;
243         struct gfs2_sbd *sdp = GFS2_SB(inode);
244         unsigned nrblocks = nr_pages * (PAGE_SIZE >> inode->i_blkbits);
245         int i;
246         int ret;
247
248         ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
249         if (ret < 0)
250                 return ret;
251
252         for(i = 0; i < nr_pages; i++) {
253                 struct page *page = pvec->pages[i];
254
255                 *done_index = page->index;
256
257                 lock_page(page);
258
259                 if (unlikely(page->mapping != mapping)) {
260 continue_unlock:
261                         unlock_page(page);
262                         continue;
263                 }
264
265                 if (!PageDirty(page)) {
266                         /* someone wrote it for us */
267                         goto continue_unlock;
268                 }
269
270                 if (PageWriteback(page)) {
271                         if (wbc->sync_mode != WB_SYNC_NONE)
272                                 wait_on_page_writeback(page);
273                         else
274                                 goto continue_unlock;
275                 }
276
277                 BUG_ON(PageWriteback(page));
278                 if (!clear_page_dirty_for_io(page))
279                         goto continue_unlock;
280
281                 trace_wbc_writepage(wbc, inode_to_bdi(inode));
282
283                 ret = __gfs2_jdata_writepage(page, wbc);
284                 if (unlikely(ret)) {
285                         if (ret == AOP_WRITEPAGE_ACTIVATE) {
286                                 unlock_page(page);
287                                 ret = 0;
288                         } else {
289
290                                 /*
291                                  * done_index is set past this page,
292                                  * so media errors will not choke
293                                  * background writeout for the entire
294                                  * file. This has consequences for
295                                  * range_cyclic semantics (ie. it may
296                                  * not be suitable for data integrity
297                                  * writeout).
298                                  */
299                                 *done_index = page->index + 1;
300                                 ret = 1;
301                                 break;
302                         }
303                 }
304
305                 /*
306                  * We stop writing back only if we are not doing
307                  * integrity sync. In case of integrity sync we have to
308                  * keep going until we have written all the pages
309                  * we tagged for writeback prior to entering this loop.
310                  */
311                 if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) {
312                         ret = 1;
313                         break;
314                 }
315
316         }
317         gfs2_trans_end(sdp);
318         return ret;
319 }
320
321 /**
322  * gfs2_write_cache_jdata - Like write_cache_pages but different
323  * @mapping: The mapping to write
324  * @wbc: The writeback control
325  *
326  * The reason that we use our own function here is that we need to
327  * start transactions before we grab page locks. This allows us
328  * to get the ordering right.
329  */
330
331 static int gfs2_write_cache_jdata(struct address_space *mapping,
332                                   struct writeback_control *wbc)
333 {
334         int ret = 0;
335         int done = 0;
336         struct pagevec pvec;
337         int nr_pages;
338         pgoff_t uninitialized_var(writeback_index);
339         pgoff_t index;
340         pgoff_t end;
341         pgoff_t done_index;
342         int cycled;
343         int range_whole = 0;
344         xa_mark_t tag;
345
346         pagevec_init(&pvec);
347         if (wbc->range_cyclic) {
348                 writeback_index = mapping->writeback_index; /* prev offset */
349                 index = writeback_index;
350                 if (index == 0)
351                         cycled = 1;
352                 else
353                         cycled = 0;
354                 end = -1;
355         } else {
356                 index = wbc->range_start >> PAGE_SHIFT;
357                 end = wbc->range_end >> PAGE_SHIFT;
358                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
359                         range_whole = 1;
360                 cycled = 1; /* ignore range_cyclic tests */
361         }
362         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
363                 tag = PAGECACHE_TAG_TOWRITE;
364         else
365                 tag = PAGECACHE_TAG_DIRTY;
366
367 retry:
368         if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
369                 tag_pages_for_writeback(mapping, index, end);
370         done_index = index;
371         while (!done && (index <= end)) {
372                 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
373                                 tag);
374                 if (nr_pages == 0)
375                         break;
376
377                 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, &done_index);
378                 if (ret)
379                         done = 1;
380                 if (ret > 0)
381                         ret = 0;
382                 pagevec_release(&pvec);
383                 cond_resched();
384         }
385
386         if (!cycled && !done) {
387                 /*
388                  * range_cyclic:
389                  * We hit the last page and there is more work to be done: wrap
390                  * back to the start of the file
391                  */
392                 cycled = 1;
393                 index = 0;
394                 end = writeback_index - 1;
395                 goto retry;
396         }
397
398         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
399                 mapping->writeback_index = done_index;
400
401         return ret;
402 }
403
404
405 /**
406  * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
407  * @mapping: The mapping to write
408  * @wbc: The writeback control
409  * 
410  */
411
412 static int gfs2_jdata_writepages(struct address_space *mapping,
413                                  struct writeback_control *wbc)
414 {
415         struct gfs2_inode *ip = GFS2_I(mapping->host);
416         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
417         int ret;
418
419         ret = gfs2_write_cache_jdata(mapping, wbc);
420         if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
421                 gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
422                                GFS2_LFC_JDATA_WPAGES);
423                 ret = gfs2_write_cache_jdata(mapping, wbc);
424         }
425         return ret;
426 }
427
428 /**
429  * stuffed_readpage - Fill in a Linux page with stuffed file data
430  * @ip: the inode
431  * @page: the page
432  *
433  * Returns: errno
434  */
435 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
436 {
437         struct buffer_head *dibh;
438         u64 dsize = i_size_read(&ip->i_inode);
439         void *kaddr;
440         int error;
441
442         /*
443          * Due to the order of unstuffing files and ->fault(), we can be
444          * asked for a zero page in the case of a stuffed file being extended,
445          * so we need to supply one here. It doesn't happen often.
446          */
447         if (unlikely(page->index)) {
448                 zero_user(page, 0, PAGE_SIZE);
449                 SetPageUptodate(page);
450                 return 0;
451         }
452
453         error = gfs2_meta_inode_buffer(ip, &dibh);
454         if (error)
455                 return error;
456
457         kaddr = kmap_atomic(page);
458         if (dsize > gfs2_max_stuffed_size(ip))
459                 dsize = gfs2_max_stuffed_size(ip);
460         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
461         memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
462         kunmap_atomic(kaddr);
463         flush_dcache_page(page);
464         brelse(dibh);
465         SetPageUptodate(page);
466
467         return 0;
468 }
469
470
471 /**
472  * __gfs2_readpage - readpage
473  * @file: The file to read a page for
474  * @page: The page to read
475  *
476  * This is the core of gfs2's readpage. It's used by the internal file
477  * reading code as in that case we already hold the glock. Also it's
478  * called by gfs2_readpage() once the required lock has been granted.
479  */
480
481 static int __gfs2_readpage(void *file, struct page *page)
482 {
483         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
484         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
485
486         int error;
487
488         if (i_blocksize(page->mapping->host) == PAGE_SIZE &&
489             !page_has_buffers(page)) {
490                 error = iomap_readpage(page, &gfs2_iomap_ops);
491         } else if (gfs2_is_stuffed(ip)) {
492                 error = stuffed_readpage(ip, page);
493                 unlock_page(page);
494         } else {
495                 error = mpage_readpage(page, gfs2_block_map);
496         }
497
498         if (unlikely(gfs2_withdrawn(sdp)))
499                 return -EIO;
500
501         return error;
502 }
503
504 /**
505  * gfs2_readpage - read a page of a file
506  * @file: The file to read
507  * @page: The page of the file
508  *
509  * This deals with the locking required. We have to unlock and
510  * relock the page in order to get the locking in the right
511  * order.
512  */
513
514 static int gfs2_readpage(struct file *file, struct page *page)
515 {
516         struct address_space *mapping = page->mapping;
517         struct gfs2_inode *ip = GFS2_I(mapping->host);
518         struct gfs2_holder gh;
519         int error;
520
521         unlock_page(page);
522         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
523         error = gfs2_glock_nq(&gh);
524         if (unlikely(error))
525                 goto out;
526         error = AOP_TRUNCATED_PAGE;
527         lock_page(page);
528         if (page->mapping == mapping && !PageUptodate(page))
529                 error = __gfs2_readpage(file, page);
530         else
531                 unlock_page(page);
532         gfs2_glock_dq(&gh);
533 out:
534         gfs2_holder_uninit(&gh);
535         if (error && error != AOP_TRUNCATED_PAGE)
536                 lock_page(page);
537         return error;
538 }
539
540 /**
541  * gfs2_internal_read - read an internal file
542  * @ip: The gfs2 inode
543  * @buf: The buffer to fill
544  * @pos: The file position
545  * @size: The amount to read
546  *
547  */
548
549 int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
550                        unsigned size)
551 {
552         struct address_space *mapping = ip->i_inode.i_mapping;
553         unsigned long index = *pos >> PAGE_SHIFT;
554         unsigned offset = *pos & (PAGE_SIZE - 1);
555         unsigned copied = 0;
556         unsigned amt;
557         struct page *page;
558         void *p;
559
560         do {
561                 amt = size - copied;
562                 if (offset + size > PAGE_SIZE)
563                         amt = PAGE_SIZE - offset;
564                 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
565                 if (IS_ERR(page))
566                         return PTR_ERR(page);
567                 p = kmap_atomic(page);
568                 memcpy(buf + copied, p + offset, amt);
569                 kunmap_atomic(p);
570                 put_page(page);
571                 copied += amt;
572                 index++;
573                 offset = 0;
574         } while(copied < size);
575         (*pos) += size;
576         return size;
577 }
578
579 /**
580  * gfs2_readpages - Read a bunch of pages at once
581  * @file: The file to read from
582  * @mapping: Address space info
583  * @pages: List of pages to read
584  * @nr_pages: Number of pages to read
585  *
586  * Some notes:
587  * 1. This is only for readahead, so we can simply ignore any things
588  *    which are slightly inconvenient (such as locking conflicts between
589  *    the page lock and the glock) and return having done no I/O. Its
590  *    obviously not something we'd want to do on too regular a basis.
591  *    Any I/O we ignore at this time will be done via readpage later.
592  * 2. We don't handle stuffed files here we let readpage do the honours.
593  * 3. mpage_readpages() does most of the heavy lifting in the common case.
594  * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
595  */
596
597 static int gfs2_readpages(struct file *file, struct address_space *mapping,
598                           struct list_head *pages, unsigned nr_pages)
599 {
600         struct inode *inode = mapping->host;
601         struct gfs2_inode *ip = GFS2_I(inode);
602         struct gfs2_sbd *sdp = GFS2_SB(inode);
603         struct gfs2_holder gh;
604         int ret;
605
606         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
607         ret = gfs2_glock_nq(&gh);
608         if (unlikely(ret))
609                 goto out_uninit;
610         if (!gfs2_is_stuffed(ip))
611                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
612         gfs2_glock_dq(&gh);
613 out_uninit:
614         gfs2_holder_uninit(&gh);
615         if (unlikely(gfs2_withdrawn(sdp)))
616                 ret = -EIO;
617         return ret;
618 }
619
620 /**
621  * adjust_fs_space - Adjusts the free space available due to gfs2_grow
622  * @inode: the rindex inode
623  */
624 void adjust_fs_space(struct inode *inode)
625 {
626         struct gfs2_sbd *sdp = GFS2_SB(inode);
627         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
628         struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
629         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
630         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
631         struct buffer_head *m_bh, *l_bh;
632         u64 fs_total, new_free;
633
634         if (gfs2_trans_begin(sdp, 2 * RES_STATFS, 0) != 0)
635                 return;
636
637         /* Total up the file system space, according to the latest rindex. */
638         fs_total = gfs2_ri_total(sdp);
639         if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
640                 goto out;
641
642         spin_lock(&sdp->sd_statfs_spin);
643         gfs2_statfs_change_in(m_sc, m_bh->b_data +
644                               sizeof(struct gfs2_dinode));
645         if (fs_total > (m_sc->sc_total + l_sc->sc_total))
646                 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
647         else
648                 new_free = 0;
649         spin_unlock(&sdp->sd_statfs_spin);
650         fs_warn(sdp, "File system extended by %llu blocks.\n",
651                 (unsigned long long)new_free);
652         gfs2_statfs_change(sdp, new_free, new_free, 0);
653
654         if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
655                 goto out2;
656         update_statfs(sdp, m_bh, l_bh);
657         brelse(l_bh);
658 out2:
659         brelse(m_bh);
660 out:
661         sdp->sd_rindex_uptodate = 0;
662         gfs2_trans_end(sdp);
663 }
664
665 /**
666  * jdata_set_page_dirty - Page dirtying function
667  * @page: The page to dirty
668  *
669  * Returns: 1 if it dirtyed the page, or 0 otherwise
670  */
671  
672 static int jdata_set_page_dirty(struct page *page)
673 {
674         SetPageChecked(page);
675         return __set_page_dirty_buffers(page);
676 }
677
678 /**
679  * gfs2_bmap - Block map function
680  * @mapping: Address space info
681  * @lblock: The block to map
682  *
683  * Returns: The disk address for the block or 0 on hole or error
684  */
685
686 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
687 {
688         struct gfs2_inode *ip = GFS2_I(mapping->host);
689         struct gfs2_holder i_gh;
690         sector_t dblock = 0;
691         int error;
692
693         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
694         if (error)
695                 return 0;
696
697         if (!gfs2_is_stuffed(ip))
698                 dblock = iomap_bmap(mapping, lblock, &gfs2_iomap_ops);
699
700         gfs2_glock_dq_uninit(&i_gh);
701
702         return dblock;
703 }
704
705 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
706 {
707         struct gfs2_bufdata *bd;
708
709         lock_buffer(bh);
710         gfs2_log_lock(sdp);
711         clear_buffer_dirty(bh);
712         bd = bh->b_private;
713         if (bd) {
714                 if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
715                         list_del_init(&bd->bd_list);
716                 else
717                         gfs2_remove_from_journal(bh, REMOVE_JDATA);
718         }
719         bh->b_bdev = NULL;
720         clear_buffer_mapped(bh);
721         clear_buffer_req(bh);
722         clear_buffer_new(bh);
723         gfs2_log_unlock(sdp);
724         unlock_buffer(bh);
725 }
726
727 static void gfs2_invalidatepage(struct page *page, unsigned int offset,
728                                 unsigned int length)
729 {
730         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
731         unsigned int stop = offset + length;
732         int partial_page = (offset || length < PAGE_SIZE);
733         struct buffer_head *bh, *head;
734         unsigned long pos = 0;
735
736         BUG_ON(!PageLocked(page));
737         if (!partial_page)
738                 ClearPageChecked(page);
739         if (!page_has_buffers(page))
740                 goto out;
741
742         bh = head = page_buffers(page);
743         do {
744                 if (pos + bh->b_size > stop)
745                         return;
746
747                 if (offset <= pos)
748                         gfs2_discard(sdp, bh);
749                 pos += bh->b_size;
750                 bh = bh->b_this_page;
751         } while (bh != head);
752 out:
753         if (!partial_page)
754                 try_to_release_page(page, 0);
755 }
756
757 /**
758  * gfs2_releasepage - free the metadata associated with a page
759  * @page: the page that's being released
760  * @gfp_mask: passed from Linux VFS, ignored by us
761  *
762  * Calls try_to_free_buffers() to free the buffers and put the page if the
763  * buffers can be released.
764  *
765  * Returns: 1 if the page was put or else 0
766  */
767
768 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
769 {
770         struct address_space *mapping = page->mapping;
771         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
772         struct buffer_head *bh, *head;
773         struct gfs2_bufdata *bd;
774
775         if (!page_has_buffers(page))
776                 return 0;
777
778         /*
779          * From xfs_vm_releasepage: mm accommodates an old ext3 case where
780          * clean pages might not have had the dirty bit cleared.  Thus, it can
781          * send actual dirty pages to ->releasepage() via shrink_active_list().
782          *
783          * As a workaround, we skip pages that contain dirty buffers below.
784          * Once ->releasepage isn't called on dirty pages anymore, we can warn
785          * on dirty buffers like we used to here again.
786          */
787
788         gfs2_log_lock(sdp);
789         spin_lock(&sdp->sd_ail_lock);
790         head = bh = page_buffers(page);
791         do {
792                 if (atomic_read(&bh->b_count))
793                         goto cannot_release;
794                 bd = bh->b_private;
795                 if (bd && bd->bd_tr)
796                         goto cannot_release;
797                 if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh)))
798                         goto cannot_release;
799                 bh = bh->b_this_page;
800         } while(bh != head);
801         spin_unlock(&sdp->sd_ail_lock);
802
803         head = bh = page_buffers(page);
804         do {
805                 bd = bh->b_private;
806                 if (bd) {
807                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
808                         if (!list_empty(&bd->bd_list))
809                                 list_del_init(&bd->bd_list);
810                         bd->bd_bh = NULL;
811                         bh->b_private = NULL;
812                         kmem_cache_free(gfs2_bufdata_cachep, bd);
813                 }
814
815                 bh = bh->b_this_page;
816         } while (bh != head);
817         gfs2_log_unlock(sdp);
818
819         return try_to_free_buffers(page);
820
821 cannot_release:
822         spin_unlock(&sdp->sd_ail_lock);
823         gfs2_log_unlock(sdp);
824         return 0;
825 }
826
827 static const struct address_space_operations gfs2_aops = {
828         .writepage = gfs2_writepage,
829         .writepages = gfs2_writepages,
830         .readpage = gfs2_readpage,
831         .readpages = gfs2_readpages,
832         .bmap = gfs2_bmap,
833         .invalidatepage = gfs2_invalidatepage,
834         .releasepage = gfs2_releasepage,
835         .direct_IO = noop_direct_IO,
836         .migratepage = buffer_migrate_page,
837         .is_partially_uptodate = block_is_partially_uptodate,
838         .error_remove_page = generic_error_remove_page,
839 };
840
841 static const struct address_space_operations gfs2_jdata_aops = {
842         .writepage = gfs2_jdata_writepage,
843         .writepages = gfs2_jdata_writepages,
844         .readpage = gfs2_readpage,
845         .readpages = gfs2_readpages,
846         .set_page_dirty = jdata_set_page_dirty,
847         .bmap = gfs2_bmap,
848         .invalidatepage = gfs2_invalidatepage,
849         .releasepage = gfs2_releasepage,
850         .is_partially_uptodate = block_is_partially_uptodate,
851         .error_remove_page = generic_error_remove_page,
852 };
853
854 void gfs2_set_aops(struct inode *inode)
855 {
856         if (gfs2_is_jdata(GFS2_I(inode)))
857                 inode->i_mapping->a_ops = &gfs2_jdata_aops;
858         else
859                 inode->i_mapping->a_ops = &gfs2_aops;
860 }