Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
[linux-2.6] / fs / gfs2 / aops.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2008 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/swap.h>
21 #include <linux/gfs2_ondisk.h>
22 #include <linux/backing-dev.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
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                 if (gfs2_is_jdata(ip))
53                         set_buffer_uptodate(bh);
54                 gfs2_trans_add_bh(ip->i_gl, bh, 0);
55         }
56 }
57
58 /**
59  * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
60  * @inode: The inode
61  * @lblock: The block number to look up
62  * @bh_result: The buffer head to return the result in
63  * @create: Non-zero if we may add block to the file
64  *
65  * Returns: errno
66  */
67
68 static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
69                                   struct buffer_head *bh_result, int create)
70 {
71         int error;
72
73         error = gfs2_block_map(inode, lblock, bh_result, 0);
74         if (error)
75                 return error;
76         if (!buffer_mapped(bh_result))
77                 return -EIO;
78         return 0;
79 }
80
81 static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
82                                  struct buffer_head *bh_result, int create)
83 {
84         return gfs2_block_map(inode, lblock, bh_result, 0);
85 }
86
87 /**
88  * gfs2_writepage_common - Common bits of writepage
89  * @page: The page to be written
90  * @wbc: The writeback control
91  *
92  * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
93  */
94
95 static int gfs2_writepage_common(struct page *page,
96                                  struct writeback_control *wbc)
97 {
98         struct inode *inode = page->mapping->host;
99         struct gfs2_inode *ip = GFS2_I(inode);
100         struct gfs2_sbd *sdp = GFS2_SB(inode);
101         loff_t i_size = i_size_read(inode);
102         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
103         unsigned offset;
104
105         if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
106                 goto out;
107         if (current->journal_info)
108                 goto redirty;
109         /* Is the page fully outside i_size? (truncate in progress) */
110         offset = i_size & (PAGE_CACHE_SIZE-1);
111         if (page->index > end_index || (page->index == end_index && !offset)) {
112                 page->mapping->a_ops->invalidatepage(page, 0);
113                 goto out;
114         }
115         return 1;
116 redirty:
117         redirty_page_for_writepage(wbc, page);
118 out:
119         unlock_page(page);
120         return 0;
121 }
122
123 /**
124  * gfs2_writeback_writepage - Write page for writeback mappings
125  * @page: The page
126  * @wbc: The writeback control
127  *
128  */
129
130 static int gfs2_writeback_writepage(struct page *page,
131                                     struct writeback_control *wbc)
132 {
133         int ret;
134
135         ret = gfs2_writepage_common(page, wbc);
136         if (ret <= 0)
137                 return ret;
138
139         ret = mpage_writepage(page, gfs2_get_block_noalloc, wbc);
140         if (ret == -EAGAIN)
141                 ret = block_write_full_page(page, gfs2_get_block_noalloc, wbc);
142         return ret;
143 }
144
145 /**
146  * gfs2_ordered_writepage - Write page for ordered data files
147  * @page: The page to write
148  * @wbc: The writeback control
149  *
150  */
151
152 static int gfs2_ordered_writepage(struct page *page,
153                                   struct writeback_control *wbc)
154 {
155         struct inode *inode = page->mapping->host;
156         struct gfs2_inode *ip = GFS2_I(inode);
157         int ret;
158
159         ret = gfs2_writepage_common(page, wbc);
160         if (ret <= 0)
161                 return ret;
162
163         if (!page_has_buffers(page)) {
164                 create_empty_buffers(page, inode->i_sb->s_blocksize,
165                                      (1 << BH_Dirty)|(1 << BH_Uptodate));
166         }
167         gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1);
168         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
169 }
170
171 /**
172  * __gfs2_jdata_writepage - The core of jdata writepage
173  * @page: The page to write
174  * @wbc: The writeback control
175  *
176  * This is shared between writepage and writepages and implements the
177  * core of the writepage operation. If a transaction is required then
178  * PageChecked will have been set and the transaction will have
179  * already been started before this is called.
180  */
181
182 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
183 {
184         struct inode *inode = page->mapping->host;
185         struct gfs2_inode *ip = GFS2_I(inode);
186         struct gfs2_sbd *sdp = GFS2_SB(inode);
187
188         if (PageChecked(page)) {
189                 ClearPageChecked(page);
190                 if (!page_has_buffers(page)) {
191                         create_empty_buffers(page, inode->i_sb->s_blocksize,
192                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
193                 }
194                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
195         }
196         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
197 }
198
199 /**
200  * gfs2_jdata_writepage - Write complete page
201  * @page: Page to write
202  *
203  * Returns: errno
204  *
205  */
206
207 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
208 {
209         struct inode *inode = page->mapping->host;
210         struct gfs2_sbd *sdp = GFS2_SB(inode);
211         int ret;
212         int done_trans = 0;
213
214         if (PageChecked(page)) {
215                 if (wbc->sync_mode != WB_SYNC_ALL)
216                         goto out_ignore;
217                 ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
218                 if (ret)
219                         goto out_ignore;
220                 done_trans = 1;
221         }
222         ret = gfs2_writepage_common(page, wbc);
223         if (ret > 0)
224                 ret = __gfs2_jdata_writepage(page, wbc);
225         if (done_trans)
226                 gfs2_trans_end(sdp);
227         return ret;
228
229 out_ignore:
230         redirty_page_for_writepage(wbc, page);
231         unlock_page(page);
232         return 0;
233 }
234
235 /**
236  * gfs2_writeback_writepages - Write a bunch of dirty pages back to disk
237  * @mapping: The mapping to write
238  * @wbc: Write-back control
239  *
240  * For the data=writeback case we can already ignore buffer heads
241  * and write whole extents at once. This is a big reduction in the
242  * number of I/O requests we send and the bmap calls we make in this case.
243  */
244 static int gfs2_writeback_writepages(struct address_space *mapping,
245                                      struct writeback_control *wbc)
246 {
247         return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
248 }
249
250 /**
251  * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
252  * @mapping: The mapping
253  * @wbc: The writeback control
254  * @writepage: The writepage function to call for each page
255  * @pvec: The vector of pages
256  * @nr_pages: The number of pages to write
257  *
258  * Returns: non-zero if loop should terminate, zero otherwise
259  */
260
261 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
262                                     struct writeback_control *wbc,
263                                     struct pagevec *pvec,
264                                     int nr_pages, pgoff_t end)
265 {
266         struct inode *inode = mapping->host;
267         struct gfs2_sbd *sdp = GFS2_SB(inode);
268         loff_t i_size = i_size_read(inode);
269         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
270         unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
271         unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
272         struct backing_dev_info *bdi = mapping->backing_dev_info;
273         int i;
274         int ret;
275
276         ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
277         if (ret < 0)
278                 return ret;
279
280         for(i = 0; i < nr_pages; i++) {
281                 struct page *page = pvec->pages[i];
282
283                 lock_page(page);
284
285                 if (unlikely(page->mapping != mapping)) {
286                         unlock_page(page);
287                         continue;
288                 }
289
290                 if (!wbc->range_cyclic && page->index > end) {
291                         ret = 1;
292                         unlock_page(page);
293                         continue;
294                 }
295
296                 if (wbc->sync_mode != WB_SYNC_NONE)
297                         wait_on_page_writeback(page);
298
299                 if (PageWriteback(page) ||
300                     !clear_page_dirty_for_io(page)) {
301                         unlock_page(page);
302                         continue;
303                 }
304
305                 /* Is the page fully outside i_size? (truncate in progress) */
306                 if (page->index > end_index || (page->index == end_index && !offset)) {
307                         page->mapping->a_ops->invalidatepage(page, 0);
308                         unlock_page(page);
309                         continue;
310                 }
311
312                 ret = __gfs2_jdata_writepage(page, wbc);
313
314                 if (ret || (--(wbc->nr_to_write) <= 0))
315                         ret = 1;
316                 if (wbc->nonblocking && bdi_write_congested(bdi)) {
317                         wbc->encountered_congestion = 1;
318                         ret = 1;
319                 }
320
321         }
322         gfs2_trans_end(sdp);
323         return ret;
324 }
325
326 /**
327  * gfs2_write_cache_jdata - Like write_cache_pages but different
328  * @mapping: The mapping to write
329  * @wbc: The writeback control
330  * @writepage: The writepage function to call
331  * @data: The data to pass to writepage
332  *
333  * The reason that we use our own function here is that we need to
334  * start transactions before we grab page locks. This allows us
335  * to get the ordering right.
336  */
337
338 static int gfs2_write_cache_jdata(struct address_space *mapping,
339                                   struct writeback_control *wbc)
340 {
341         struct backing_dev_info *bdi = mapping->backing_dev_info;
342         int ret = 0;
343         int done = 0;
344         struct pagevec pvec;
345         int nr_pages;
346         pgoff_t index;
347         pgoff_t end;
348         int scanned = 0;
349         int range_whole = 0;
350
351         if (wbc->nonblocking && bdi_write_congested(bdi)) {
352                 wbc->encountered_congestion = 1;
353                 return 0;
354         }
355
356         pagevec_init(&pvec, 0);
357         if (wbc->range_cyclic) {
358                 index = mapping->writeback_index; /* Start from prev offset */
359                 end = -1;
360         } else {
361                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
362                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
363                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
364                         range_whole = 1;
365                 scanned = 1;
366         }
367
368 retry:
369          while (!done && (index <= end) &&
370                 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
371                                                PAGECACHE_TAG_DIRTY,
372                                                min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
373                 scanned = 1;
374                 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
375                 if (ret)
376                         done = 1;
377                 if (ret > 0)
378                         ret = 0;
379
380                 pagevec_release(&pvec);
381                 cond_resched();
382         }
383
384         if (!scanned && !done) {
385                 /*
386                  * We hit the last page and there is more work to be done: wrap
387                  * back to the start of the file
388                  */
389                 scanned = 1;
390                 index = 0;
391                 goto retry;
392         }
393
394         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
395                 mapping->writeback_index = index;
396         return ret;
397 }
398
399
400 /**
401  * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
402  * @mapping: The mapping to write
403  * @wbc: The writeback control
404  * 
405  */
406
407 static int gfs2_jdata_writepages(struct address_space *mapping,
408                                  struct writeback_control *wbc)
409 {
410         struct gfs2_inode *ip = GFS2_I(mapping->host);
411         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
412         int ret;
413
414         ret = gfs2_write_cache_jdata(mapping, wbc);
415         if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
416                 gfs2_log_flush(sdp, ip->i_gl);
417                 ret = gfs2_write_cache_jdata(mapping, wbc);
418         }
419         return ret;
420 }
421
422 /**
423  * stuffed_readpage - Fill in a Linux page with stuffed file data
424  * @ip: the inode
425  * @page: the page
426  *
427  * Returns: errno
428  */
429
430 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
431 {
432         struct buffer_head *dibh;
433         void *kaddr;
434         int error;
435
436         /*
437          * Due to the order of unstuffing files and ->fault(), we can be
438          * asked for a zero page in the case of a stuffed file being extended,
439          * so we need to supply one here. It doesn't happen often.
440          */
441         if (unlikely(page->index)) {
442                 zero_user(page, 0, PAGE_CACHE_SIZE);
443                 SetPageUptodate(page);
444                 return 0;
445         }
446
447         error = gfs2_meta_inode_buffer(ip, &dibh);
448         if (error)
449                 return error;
450
451         kaddr = kmap_atomic(page, KM_USER0);
452         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
453                ip->i_disksize);
454         memset(kaddr + ip->i_disksize, 0, PAGE_CACHE_SIZE - ip->i_disksize);
455         kunmap_atomic(kaddr, KM_USER0);
456         flush_dcache_page(page);
457         brelse(dibh);
458         SetPageUptodate(page);
459
460         return 0;
461 }
462
463
464 /**
465  * __gfs2_readpage - readpage
466  * @file: The file to read a page for
467  * @page: The page to read
468  *
469  * This is the core of gfs2's readpage. Its used by the internal file
470  * reading code as in that case we already hold the glock. Also its
471  * called by gfs2_readpage() once the required lock has been granted.
472  *
473  */
474
475 static int __gfs2_readpage(void *file, struct page *page)
476 {
477         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
478         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
479         int error;
480
481         if (gfs2_is_stuffed(ip)) {
482                 error = stuffed_readpage(ip, page);
483                 unlock_page(page);
484         } else {
485                 error = mpage_readpage(page, gfs2_block_map);
486         }
487
488         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
489                 return -EIO;
490
491         return error;
492 }
493
494 /**
495  * gfs2_readpage - read a page of a file
496  * @file: The file to read
497  * @page: The page of the file
498  *
499  * This deals with the locking required. We have to unlock and
500  * relock the page in order to get the locking in the right
501  * order.
502  */
503
504 static int gfs2_readpage(struct file *file, struct page *page)
505 {
506         struct address_space *mapping = page->mapping;
507         struct gfs2_inode *ip = GFS2_I(mapping->host);
508         struct gfs2_holder gh;
509         int error;
510
511         unlock_page(page);
512         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
513         error = gfs2_glock_nq(&gh);
514         if (unlikely(error))
515                 goto out;
516         error = AOP_TRUNCATED_PAGE;
517         lock_page(page);
518         if (page->mapping == mapping && !PageUptodate(page))
519                 error = __gfs2_readpage(file, page);
520         else
521                 unlock_page(page);
522         gfs2_glock_dq(&gh);
523 out:
524         gfs2_holder_uninit(&gh);
525         if (error && error != AOP_TRUNCATED_PAGE)
526                 lock_page(page);
527         return error;
528 }
529
530 /**
531  * gfs2_internal_read - read an internal file
532  * @ip: The gfs2 inode
533  * @ra_state: The readahead state (or NULL for no readahead)
534  * @buf: The buffer to fill
535  * @pos: The file position
536  * @size: The amount to read
537  *
538  */
539
540 int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
541                        char *buf, loff_t *pos, unsigned size)
542 {
543         struct address_space *mapping = ip->i_inode.i_mapping;
544         unsigned long index = *pos / PAGE_CACHE_SIZE;
545         unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
546         unsigned copied = 0;
547         unsigned amt;
548         struct page *page;
549         void *p;
550
551         do {
552                 amt = size - copied;
553                 if (offset + size > PAGE_CACHE_SIZE)
554                         amt = PAGE_CACHE_SIZE - offset;
555                 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
556                 if (IS_ERR(page))
557                         return PTR_ERR(page);
558                 p = kmap_atomic(page, KM_USER0);
559                 memcpy(buf + copied, p + offset, amt);
560                 kunmap_atomic(p, KM_USER0);
561                 mark_page_accessed(page);
562                 page_cache_release(page);
563                 copied += amt;
564                 index++;
565                 offset = 0;
566         } while(copied < size);
567         (*pos) += size;
568         return size;
569 }
570
571 /**
572  * gfs2_readpages - Read a bunch of pages at once
573  *
574  * Some notes:
575  * 1. This is only for readahead, so we can simply ignore any things
576  *    which are slightly inconvenient (such as locking conflicts between
577  *    the page lock and the glock) and return having done no I/O. Its
578  *    obviously not something we'd want to do on too regular a basis.
579  *    Any I/O we ignore at this time will be done via readpage later.
580  * 2. We don't handle stuffed files here we let readpage do the honours.
581  * 3. mpage_readpages() does most of the heavy lifting in the common case.
582  * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
583  */
584
585 static int gfs2_readpages(struct file *file, struct address_space *mapping,
586                           struct list_head *pages, unsigned nr_pages)
587 {
588         struct inode *inode = mapping->host;
589         struct gfs2_inode *ip = GFS2_I(inode);
590         struct gfs2_sbd *sdp = GFS2_SB(inode);
591         struct gfs2_holder gh;
592         int ret;
593
594         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
595         ret = gfs2_glock_nq(&gh);
596         if (unlikely(ret))
597                 goto out_uninit;
598         if (!gfs2_is_stuffed(ip))
599                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
600         gfs2_glock_dq(&gh);
601 out_uninit:
602         gfs2_holder_uninit(&gh);
603         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
604                 ret = -EIO;
605         return ret;
606 }
607
608 /**
609  * gfs2_write_begin - Begin to write to a file
610  * @file: The file to write to
611  * @mapping: The mapping in which to write
612  * @pos: The file offset at which to start writing
613  * @len: Length of the write
614  * @flags: Various flags
615  * @pagep: Pointer to return the page
616  * @fsdata: Pointer to return fs data (unused by GFS2)
617  *
618  * Returns: errno
619  */
620
621 static int gfs2_write_begin(struct file *file, struct address_space *mapping,
622                             loff_t pos, unsigned len, unsigned flags,
623                             struct page **pagep, void **fsdata)
624 {
625         struct gfs2_inode *ip = GFS2_I(mapping->host);
626         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
627         unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
628         int alloc_required;
629         int error = 0;
630         struct gfs2_alloc *al;
631         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
632         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
633         unsigned to = from + len;
634         struct page *page;
635
636         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
637         error = gfs2_glock_nq(&ip->i_gh);
638         if (unlikely(error))
639                 goto out_uninit;
640
641         error = gfs2_write_alloc_required(ip, pos, len, &alloc_required);
642         if (error)
643                 goto out_unlock;
644
645         if (alloc_required || gfs2_is_jdata(ip))
646                 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
647
648         if (alloc_required) {
649                 al = gfs2_alloc_get(ip);
650                 if (!al) {
651                         error = -ENOMEM;
652                         goto out_unlock;
653                 }
654
655                 error = gfs2_quota_lock_check(ip);
656                 if (error)
657                         goto out_alloc_put;
658
659                 al->al_requested = data_blocks + ind_blocks;
660                 error = gfs2_inplace_reserve(ip);
661                 if (error)
662                         goto out_qunlock;
663         }
664
665         rblocks = RES_DINODE + ind_blocks;
666         if (gfs2_is_jdata(ip))
667                 rblocks += data_blocks ? data_blocks : 1;
668         if (ind_blocks || data_blocks)
669                 rblocks += RES_STATFS + RES_QUOTA;
670
671         error = gfs2_trans_begin(sdp, rblocks,
672                                  PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
673         if (error)
674                 goto out_trans_fail;
675
676         error = -ENOMEM;
677         flags |= AOP_FLAG_NOFS;
678         page = grab_cache_page_write_begin(mapping, index, flags);
679         *pagep = page;
680         if (unlikely(!page))
681                 goto out_endtrans;
682
683         if (gfs2_is_stuffed(ip)) {
684                 error = 0;
685                 if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
686                         error = gfs2_unstuff_dinode(ip, page);
687                         if (error == 0)
688                                 goto prepare_write;
689                 } else if (!PageUptodate(page)) {
690                         error = stuffed_readpage(ip, page);
691                 }
692                 goto out;
693         }
694
695 prepare_write:
696         error = block_prepare_write(page, from, to, gfs2_block_map);
697 out:
698         if (error == 0)
699                 return 0;
700
701         page_cache_release(page);
702         if (pos + len > ip->i_inode.i_size)
703                 vmtruncate(&ip->i_inode, ip->i_inode.i_size);
704 out_endtrans:
705         gfs2_trans_end(sdp);
706 out_trans_fail:
707         if (alloc_required) {
708                 gfs2_inplace_release(ip);
709 out_qunlock:
710                 gfs2_quota_unlock(ip);
711 out_alloc_put:
712                 gfs2_alloc_put(ip);
713         }
714 out_unlock:
715         gfs2_glock_dq(&ip->i_gh);
716 out_uninit:
717         gfs2_holder_uninit(&ip->i_gh);
718         return error;
719 }
720
721 /**
722  * adjust_fs_space - Adjusts the free space available due to gfs2_grow
723  * @inode: the rindex inode
724  */
725 static void adjust_fs_space(struct inode *inode)
726 {
727         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
728         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
729         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
730         u64 fs_total, new_free;
731
732         /* Total up the file system space, according to the latest rindex. */
733         fs_total = gfs2_ri_total(sdp);
734
735         spin_lock(&sdp->sd_statfs_spin);
736         if (fs_total > (m_sc->sc_total + l_sc->sc_total))
737                 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
738         else
739                 new_free = 0;
740         spin_unlock(&sdp->sd_statfs_spin);
741         fs_warn(sdp, "File system extended by %llu blocks.\n",
742                 (unsigned long long)new_free);
743         gfs2_statfs_change(sdp, new_free, new_free, 0);
744 }
745
746 /**
747  * gfs2_stuffed_write_end - Write end for stuffed files
748  * @inode: The inode
749  * @dibh: The buffer_head containing the on-disk inode
750  * @pos: The file position
751  * @len: The length of the write
752  * @copied: How much was actually copied by the VFS
753  * @page: The page
754  *
755  * This copies the data from the page into the inode block after
756  * the inode data structure itself.
757  *
758  * Returns: errno
759  */
760 static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
761                                   loff_t pos, unsigned len, unsigned copied,
762                                   struct page *page)
763 {
764         struct gfs2_inode *ip = GFS2_I(inode);
765         struct gfs2_sbd *sdp = GFS2_SB(inode);
766         u64 to = pos + copied;
767         void *kaddr;
768         unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
769         struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
770
771         BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
772         kaddr = kmap_atomic(page, KM_USER0);
773         memcpy(buf + pos, kaddr + pos, copied);
774         memset(kaddr + pos + copied, 0, len - copied);
775         flush_dcache_page(page);
776         kunmap_atomic(kaddr, KM_USER0);
777
778         if (!PageUptodate(page))
779                 SetPageUptodate(page);
780         unlock_page(page);
781         page_cache_release(page);
782
783         if (copied) {
784                 if (inode->i_size < to) {
785                         i_size_write(inode, to);
786                         ip->i_disksize = inode->i_size;
787                 }
788                 gfs2_dinode_out(ip, di);
789                 mark_inode_dirty(inode);
790         }
791
792         if (inode == sdp->sd_rindex)
793                 adjust_fs_space(inode);
794
795         brelse(dibh);
796         gfs2_trans_end(sdp);
797         gfs2_glock_dq(&ip->i_gh);
798         gfs2_holder_uninit(&ip->i_gh);
799         return copied;
800 }
801
802 /**
803  * gfs2_write_end
804  * @file: The file to write to
805  * @mapping: The address space to write to
806  * @pos: The file position
807  * @len: The length of the data
808  * @copied:
809  * @page: The page that has been written
810  * @fsdata: The fsdata (unused in GFS2)
811  *
812  * The main write_end function for GFS2. We have a separate one for
813  * stuffed files as they are slightly different, otherwise we just
814  * put our locking around the VFS provided functions.
815  *
816  * Returns: errno
817  */
818
819 static int gfs2_write_end(struct file *file, struct address_space *mapping,
820                           loff_t pos, unsigned len, unsigned copied,
821                           struct page *page, void *fsdata)
822 {
823         struct inode *inode = page->mapping->host;
824         struct gfs2_inode *ip = GFS2_I(inode);
825         struct gfs2_sbd *sdp = GFS2_SB(inode);
826         struct buffer_head *dibh;
827         struct gfs2_alloc *al = ip->i_alloc;
828         unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
829         unsigned int to = from + len;
830         int ret;
831
832         BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
833
834         ret = gfs2_meta_inode_buffer(ip, &dibh);
835         if (unlikely(ret)) {
836                 unlock_page(page);
837                 page_cache_release(page);
838                 goto failed;
839         }
840
841         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
842
843         if (gfs2_is_stuffed(ip))
844                 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
845
846         if (!gfs2_is_writeback(ip))
847                 gfs2_page_add_databufs(ip, page, from, to);
848
849         ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
850         if (ret > 0) {
851                 if (inode->i_size > ip->i_disksize)
852                         ip->i_disksize = inode->i_size;
853                 gfs2_dinode_out(ip, dibh->b_data);
854                 mark_inode_dirty(inode);
855         }
856
857         if (inode == sdp->sd_rindex)
858                 adjust_fs_space(inode);
859
860         brelse(dibh);
861         gfs2_trans_end(sdp);
862 failed:
863         if (al) {
864                 gfs2_inplace_release(ip);
865                 gfs2_quota_unlock(ip);
866                 gfs2_alloc_put(ip);
867         }
868         gfs2_glock_dq(&ip->i_gh);
869         gfs2_holder_uninit(&ip->i_gh);
870         return ret;
871 }
872
873 /**
874  * gfs2_set_page_dirty - Page dirtying function
875  * @page: The page to dirty
876  *
877  * Returns: 1 if it dirtyed the page, or 0 otherwise
878  */
879  
880 static int gfs2_set_page_dirty(struct page *page)
881 {
882         SetPageChecked(page);
883         return __set_page_dirty_buffers(page);
884 }
885
886 /**
887  * gfs2_bmap - Block map function
888  * @mapping: Address space info
889  * @lblock: The block to map
890  *
891  * Returns: The disk address for the block or 0 on hole or error
892  */
893
894 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
895 {
896         struct gfs2_inode *ip = GFS2_I(mapping->host);
897         struct gfs2_holder i_gh;
898         sector_t dblock = 0;
899         int error;
900
901         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
902         if (error)
903                 return 0;
904
905         if (!gfs2_is_stuffed(ip))
906                 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map);
907
908         gfs2_glock_dq_uninit(&i_gh);
909
910         return dblock;
911 }
912
913 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
914 {
915         struct gfs2_bufdata *bd;
916
917         lock_buffer(bh);
918         gfs2_log_lock(sdp);
919         clear_buffer_dirty(bh);
920         bd = bh->b_private;
921         if (bd) {
922                 if (!list_empty(&bd->bd_le.le_list) && !buffer_pinned(bh))
923                         list_del_init(&bd->bd_le.le_list);
924                 else
925                         gfs2_remove_from_journal(bh, current->journal_info, 0);
926         }
927         bh->b_bdev = NULL;
928         clear_buffer_mapped(bh);
929         clear_buffer_req(bh);
930         clear_buffer_new(bh);
931         gfs2_log_unlock(sdp);
932         unlock_buffer(bh);
933 }
934
935 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
936 {
937         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
938         struct buffer_head *bh, *head;
939         unsigned long pos = 0;
940
941         BUG_ON(!PageLocked(page));
942         if (offset == 0)
943                 ClearPageChecked(page);
944         if (!page_has_buffers(page))
945                 goto out;
946
947         bh = head = page_buffers(page);
948         do {
949                 if (offset <= pos)
950                         gfs2_discard(sdp, bh);
951                 pos += bh->b_size;
952                 bh = bh->b_this_page;
953         } while (bh != head);
954 out:
955         if (offset == 0)
956                 try_to_release_page(page, 0);
957 }
958
959 /**
960  * gfs2_ok_for_dio - check that dio is valid on this file
961  * @ip: The inode
962  * @rw: READ or WRITE
963  * @offset: The offset at which we are reading or writing
964  *
965  * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
966  *          1 (to accept the i/o request)
967  */
968 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
969 {
970         /*
971          * Should we return an error here? I can't see that O_DIRECT for
972          * a stuffed file makes any sense. For now we'll silently fall
973          * back to buffered I/O
974          */
975         if (gfs2_is_stuffed(ip))
976                 return 0;
977
978         if (offset >= i_size_read(&ip->i_inode))
979                 return 0;
980         return 1;
981 }
982
983
984
985 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
986                               const struct iovec *iov, loff_t offset,
987                               unsigned long nr_segs)
988 {
989         struct file *file = iocb->ki_filp;
990         struct inode *inode = file->f_mapping->host;
991         struct gfs2_inode *ip = GFS2_I(inode);
992         struct gfs2_holder gh;
993         int rv;
994
995         /*
996          * Deferred lock, even if its a write, since we do no allocation
997          * on this path. All we need change is atime, and this lock mode
998          * ensures that other nodes have flushed their buffered read caches
999          * (i.e. their page cache entries for this inode). We do not,
1000          * unfortunately have the option of only flushing a range like
1001          * the VFS does.
1002          */
1003         gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
1004         rv = gfs2_glock_nq(&gh);
1005         if (rv)
1006                 return rv;
1007         rv = gfs2_ok_for_dio(ip, rw, offset);
1008         if (rv != 1)
1009                 goto out; /* dio not valid, fall back to buffered i/o */
1010
1011         rv = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev,
1012                                            iov, offset, nr_segs,
1013                                            gfs2_get_block_direct, NULL);
1014 out:
1015         gfs2_glock_dq_m(1, &gh);
1016         gfs2_holder_uninit(&gh);
1017         return rv;
1018 }
1019
1020 /**
1021  * gfs2_releasepage - free the metadata associated with a page
1022  * @page: the page that's being released
1023  * @gfp_mask: passed from Linux VFS, ignored by us
1024  *
1025  * Call try_to_free_buffers() if the buffers in this page can be
1026  * released.
1027  *
1028  * Returns: 0
1029  */
1030
1031 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
1032 {
1033         struct inode *aspace = page->mapping->host;
1034         struct gfs2_sbd *sdp = aspace->i_sb->s_fs_info;
1035         struct buffer_head *bh, *head;
1036         struct gfs2_bufdata *bd;
1037
1038         if (!page_has_buffers(page))
1039                 return 0;
1040
1041         gfs2_log_lock(sdp);
1042         head = bh = page_buffers(page);
1043         do {
1044                 if (atomic_read(&bh->b_count))
1045                         goto cannot_release;
1046                 bd = bh->b_private;
1047                 if (bd && bd->bd_ail)
1048                         goto cannot_release;
1049                 gfs2_assert_warn(sdp, !buffer_pinned(bh));
1050                 gfs2_assert_warn(sdp, !buffer_dirty(bh));
1051                 bh = bh->b_this_page;
1052         } while(bh != head);
1053         gfs2_log_unlock(sdp);
1054
1055         head = bh = page_buffers(page);
1056         do {
1057                 gfs2_log_lock(sdp);
1058                 bd = bh->b_private;
1059                 if (bd) {
1060                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
1061                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
1062                         if (!list_empty(&bd->bd_le.le_list)) {
1063                                 if (!buffer_pinned(bh))
1064                                         list_del_init(&bd->bd_le.le_list);
1065                                 else
1066                                         bd = NULL;
1067                         }
1068                         if (bd)
1069                                 bd->bd_bh = NULL;
1070                         bh->b_private = NULL;
1071                 }
1072                 gfs2_log_unlock(sdp);
1073                 if (bd)
1074                         kmem_cache_free(gfs2_bufdata_cachep, bd);
1075
1076                 bh = bh->b_this_page;
1077         } while (bh != head);
1078
1079         return try_to_free_buffers(page);
1080 cannot_release:
1081         gfs2_log_unlock(sdp);
1082         return 0;
1083 }
1084
1085 static const struct address_space_operations gfs2_writeback_aops = {
1086         .writepage = gfs2_writeback_writepage,
1087         .writepages = gfs2_writeback_writepages,
1088         .readpage = gfs2_readpage,
1089         .readpages = gfs2_readpages,
1090         .sync_page = block_sync_page,
1091         .write_begin = gfs2_write_begin,
1092         .write_end = gfs2_write_end,
1093         .bmap = gfs2_bmap,
1094         .invalidatepage = gfs2_invalidatepage,
1095         .releasepage = gfs2_releasepage,
1096         .direct_IO = gfs2_direct_IO,
1097         .migratepage = buffer_migrate_page,
1098         .is_partially_uptodate = block_is_partially_uptodate,
1099 };
1100
1101 static const struct address_space_operations gfs2_ordered_aops = {
1102         .writepage = gfs2_ordered_writepage,
1103         .readpage = gfs2_readpage,
1104         .readpages = gfs2_readpages,
1105         .sync_page = block_sync_page,
1106         .write_begin = gfs2_write_begin,
1107         .write_end = gfs2_write_end,
1108         .set_page_dirty = gfs2_set_page_dirty,
1109         .bmap = gfs2_bmap,
1110         .invalidatepage = gfs2_invalidatepage,
1111         .releasepage = gfs2_releasepage,
1112         .direct_IO = gfs2_direct_IO,
1113         .migratepage = buffer_migrate_page,
1114         .is_partially_uptodate = block_is_partially_uptodate,
1115 };
1116
1117 static const struct address_space_operations gfs2_jdata_aops = {
1118         .writepage = gfs2_jdata_writepage,
1119         .writepages = gfs2_jdata_writepages,
1120         .readpage = gfs2_readpage,
1121         .readpages = gfs2_readpages,
1122         .sync_page = block_sync_page,
1123         .write_begin = gfs2_write_begin,
1124         .write_end = gfs2_write_end,
1125         .set_page_dirty = gfs2_set_page_dirty,
1126         .bmap = gfs2_bmap,
1127         .invalidatepage = gfs2_invalidatepage,
1128         .releasepage = gfs2_releasepage,
1129         .is_partially_uptodate = block_is_partially_uptodate,
1130 };
1131
1132 void gfs2_set_aops(struct inode *inode)
1133 {
1134         struct gfs2_inode *ip = GFS2_I(inode);
1135
1136         if (gfs2_is_writeback(ip))
1137                 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1138         else if (gfs2_is_ordered(ip))
1139                 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1140         else if (gfs2_is_jdata(ip))
1141                 inode->i_mapping->a_ops = &gfs2_jdata_aops;
1142         else
1143                 BUG();
1144 }
1145