Btrfs: calc file extent num_bytes correctly in file clone
[linux-2.6.git] / 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 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         return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
140 }
141
142 /**
143  * gfs2_ordered_writepage - Write page for ordered data files
144  * @page: The page to write
145  * @wbc: The writeback control
146  *
147  */
148
149 static int gfs2_ordered_writepage(struct page *page,
150                                   struct writeback_control *wbc)
151 {
152         struct inode *inode = page->mapping->host;
153         struct gfs2_inode *ip = GFS2_I(inode);
154         int ret;
155
156         ret = gfs2_writepage_common(page, wbc);
157         if (ret <= 0)
158                 return ret;
159
160         if (!page_has_buffers(page)) {
161                 create_empty_buffers(page, inode->i_sb->s_blocksize,
162                                      (1 << BH_Dirty)|(1 << BH_Uptodate));
163         }
164         gfs2_page_add_databufs(ip, page, 0, inode->i_sb->s_blocksize-1);
165         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
166 }
167
168 /**
169  * __gfs2_jdata_writepage - The core of jdata writepage
170  * @page: The page to write
171  * @wbc: The writeback control
172  *
173  * This is shared between writepage and writepages and implements the
174  * core of the writepage operation. If a transaction is required then
175  * PageChecked will have been set and the transaction will have
176  * already been started before this is called.
177  */
178
179 static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
180 {
181         struct inode *inode = page->mapping->host;
182         struct gfs2_inode *ip = GFS2_I(inode);
183         struct gfs2_sbd *sdp = GFS2_SB(inode);
184
185         if (PageChecked(page)) {
186                 ClearPageChecked(page);
187                 if (!page_has_buffers(page)) {
188                         create_empty_buffers(page, inode->i_sb->s_blocksize,
189                                              (1 << BH_Dirty)|(1 << BH_Uptodate));
190                 }
191                 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize-1);
192         }
193         return block_write_full_page(page, gfs2_get_block_noalloc, wbc);
194 }
195
196 /**
197  * gfs2_jdata_writepage - Write complete page
198  * @page: Page to write
199  *
200  * Returns: errno
201  *
202  */
203
204 static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
205 {
206         struct inode *inode = page->mapping->host;
207         struct gfs2_sbd *sdp = GFS2_SB(inode);
208         int ret;
209         int done_trans = 0;
210
211         if (PageChecked(page)) {
212                 if (wbc->sync_mode != WB_SYNC_ALL)
213                         goto out_ignore;
214                 ret = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
215                 if (ret)
216                         goto out_ignore;
217                 done_trans = 1;
218         }
219         ret = gfs2_writepage_common(page, wbc);
220         if (ret > 0)
221                 ret = __gfs2_jdata_writepage(page, wbc);
222         if (done_trans)
223                 gfs2_trans_end(sdp);
224         return ret;
225
226 out_ignore:
227         redirty_page_for_writepage(wbc, page);
228         unlock_page(page);
229         return 0;
230 }
231
232 /**
233  * gfs2_writeback_writepages - Write a bunch of dirty pages back to disk
234  * @mapping: The mapping to write
235  * @wbc: Write-back control
236  *
237  * For the data=writeback case we can already ignore buffer heads
238  * and write whole extents at once. This is a big reduction in the
239  * number of I/O requests we send and the bmap calls we make in this case.
240  */
241 static int gfs2_writeback_writepages(struct address_space *mapping,
242                                      struct writeback_control *wbc)
243 {
244         return mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
245 }
246
247 /**
248  * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
249  * @mapping: The mapping
250  * @wbc: The writeback control
251  * @writepage: The writepage function to call for each page
252  * @pvec: The vector of pages
253  * @nr_pages: The number of pages to write
254  *
255  * Returns: non-zero if loop should terminate, zero otherwise
256  */
257
258 static int gfs2_write_jdata_pagevec(struct address_space *mapping,
259                                     struct writeback_control *wbc,
260                                     struct pagevec *pvec,
261                                     int nr_pages, pgoff_t end)
262 {
263         struct inode *inode = mapping->host;
264         struct gfs2_sbd *sdp = GFS2_SB(inode);
265         loff_t i_size = i_size_read(inode);
266         pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
267         unsigned offset = i_size & (PAGE_CACHE_SIZE-1);
268         unsigned nrblocks = nr_pages * (PAGE_CACHE_SIZE/inode->i_sb->s_blocksize);
269         int i;
270         int ret;
271
272         ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
273         if (ret < 0)
274                 return ret;
275
276         for(i = 0; i < nr_pages; i++) {
277                 struct page *page = pvec->pages[i];
278
279                 lock_page(page);
280
281                 if (unlikely(page->mapping != mapping)) {
282                         unlock_page(page);
283                         continue;
284                 }
285
286                 if (!wbc->range_cyclic && page->index > end) {
287                         ret = 1;
288                         unlock_page(page);
289                         continue;
290                 }
291
292                 if (wbc->sync_mode != WB_SYNC_NONE)
293                         wait_on_page_writeback(page);
294
295                 if (PageWriteback(page) ||
296                     !clear_page_dirty_for_io(page)) {
297                         unlock_page(page);
298                         continue;
299                 }
300
301                 /* Is the page fully outside i_size? (truncate in progress) */
302                 if (page->index > end_index || (page->index == end_index && !offset)) {
303                         page->mapping->a_ops->invalidatepage(page, 0);
304                         unlock_page(page);
305                         continue;
306                 }
307
308                 ret = __gfs2_jdata_writepage(page, wbc);
309
310                 if (ret || (--(wbc->nr_to_write) <= 0))
311                         ret = 1;
312         }
313         gfs2_trans_end(sdp);
314         return ret;
315 }
316
317 /**
318  * gfs2_write_cache_jdata - Like write_cache_pages but different
319  * @mapping: The mapping to write
320  * @wbc: The writeback control
321  * @writepage: The writepage function to call
322  * @data: The data to pass to writepage
323  *
324  * The reason that we use our own function here is that we need to
325  * start transactions before we grab page locks. This allows us
326  * to get the ordering right.
327  */
328
329 static int gfs2_write_cache_jdata(struct address_space *mapping,
330                                   struct writeback_control *wbc)
331 {
332         int ret = 0;
333         int done = 0;
334         struct pagevec pvec;
335         int nr_pages;
336         pgoff_t index;
337         pgoff_t end;
338         int scanned = 0;
339         int range_whole = 0;
340
341         pagevec_init(&pvec, 0);
342         if (wbc->range_cyclic) {
343                 index = mapping->writeback_index; /* Start from prev offset */
344                 end = -1;
345         } else {
346                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
347                 end = wbc->range_end >> PAGE_CACHE_SHIFT;
348                 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
349                         range_whole = 1;
350                 scanned = 1;
351         }
352
353 retry:
354          while (!done && (index <= end) &&
355                 (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
356                                                PAGECACHE_TAG_DIRTY,
357                                                min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
358                 scanned = 1;
359                 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, end);
360                 if (ret)
361                         done = 1;
362                 if (ret > 0)
363                         ret = 0;
364
365                 pagevec_release(&pvec);
366                 cond_resched();
367         }
368
369         if (!scanned && !done) {
370                 /*
371                  * We hit the last page and there is more work to be done: wrap
372                  * back to the start of the file
373                  */
374                 scanned = 1;
375                 index = 0;
376                 goto retry;
377         }
378
379         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
380                 mapping->writeback_index = index;
381         return ret;
382 }
383
384
385 /**
386  * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
387  * @mapping: The mapping to write
388  * @wbc: The writeback control
389  * 
390  */
391
392 static int gfs2_jdata_writepages(struct address_space *mapping,
393                                  struct writeback_control *wbc)
394 {
395         struct gfs2_inode *ip = GFS2_I(mapping->host);
396         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
397         int ret;
398
399         ret = gfs2_write_cache_jdata(mapping, wbc);
400         if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
401                 gfs2_log_flush(sdp, ip->i_gl);
402                 ret = gfs2_write_cache_jdata(mapping, wbc);
403         }
404         return ret;
405 }
406
407 /**
408  * stuffed_readpage - Fill in a Linux page with stuffed file data
409  * @ip: the inode
410  * @page: the page
411  *
412  * Returns: errno
413  */
414
415 static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
416 {
417         struct buffer_head *dibh;
418         u64 dsize = i_size_read(&ip->i_inode);
419         void *kaddr;
420         int error;
421
422         /*
423          * Due to the order of unstuffing files and ->fault(), we can be
424          * asked for a zero page in the case of a stuffed file being extended,
425          * so we need to supply one here. It doesn't happen often.
426          */
427         if (unlikely(page->index)) {
428                 zero_user(page, 0, PAGE_CACHE_SIZE);
429                 SetPageUptodate(page);
430                 return 0;
431         }
432
433         error = gfs2_meta_inode_buffer(ip, &dibh);
434         if (error)
435                 return error;
436
437         kaddr = kmap_atomic(page, KM_USER0);
438         if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode)))
439                 dsize = (dibh->b_size - sizeof(struct gfs2_dinode));
440         memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
441         memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize);
442         kunmap_atomic(kaddr, KM_USER0);
443         flush_dcache_page(page);
444         brelse(dibh);
445         SetPageUptodate(page);
446
447         return 0;
448 }
449
450
451 /**
452  * __gfs2_readpage - readpage
453  * @file: The file to read a page for
454  * @page: The page to read
455  *
456  * This is the core of gfs2's readpage. Its used by the internal file
457  * reading code as in that case we already hold the glock. Also its
458  * called by gfs2_readpage() once the required lock has been granted.
459  *
460  */
461
462 static int __gfs2_readpage(void *file, struct page *page)
463 {
464         struct gfs2_inode *ip = GFS2_I(page->mapping->host);
465         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
466         int error;
467
468         if (gfs2_is_stuffed(ip)) {
469                 error = stuffed_readpage(ip, page);
470                 unlock_page(page);
471         } else {
472                 error = mpage_readpage(page, gfs2_block_map);
473         }
474
475         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
476                 return -EIO;
477
478         return error;
479 }
480
481 /**
482  * gfs2_readpage - read a page of a file
483  * @file: The file to read
484  * @page: The page of the file
485  *
486  * This deals with the locking required. We have to unlock and
487  * relock the page in order to get the locking in the right
488  * order.
489  */
490
491 static int gfs2_readpage(struct file *file, struct page *page)
492 {
493         struct address_space *mapping = page->mapping;
494         struct gfs2_inode *ip = GFS2_I(mapping->host);
495         struct gfs2_holder gh;
496         int error;
497
498         unlock_page(page);
499         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
500         error = gfs2_glock_nq(&gh);
501         if (unlikely(error))
502                 goto out;
503         error = AOP_TRUNCATED_PAGE;
504         lock_page(page);
505         if (page->mapping == mapping && !PageUptodate(page))
506                 error = __gfs2_readpage(file, page);
507         else
508                 unlock_page(page);
509         gfs2_glock_dq(&gh);
510 out:
511         gfs2_holder_uninit(&gh);
512         if (error && error != AOP_TRUNCATED_PAGE)
513                 lock_page(page);
514         return error;
515 }
516
517 /**
518  * gfs2_internal_read - read an internal file
519  * @ip: The gfs2 inode
520  * @ra_state: The readahead state (or NULL for no readahead)
521  * @buf: The buffer to fill
522  * @pos: The file position
523  * @size: The amount to read
524  *
525  */
526
527 int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
528                        char *buf, loff_t *pos, unsigned size)
529 {
530         struct address_space *mapping = ip->i_inode.i_mapping;
531         unsigned long index = *pos / PAGE_CACHE_SIZE;
532         unsigned offset = *pos & (PAGE_CACHE_SIZE - 1);
533         unsigned copied = 0;
534         unsigned amt;
535         struct page *page;
536         void *p;
537
538         do {
539                 amt = size - copied;
540                 if (offset + size > PAGE_CACHE_SIZE)
541                         amt = PAGE_CACHE_SIZE - offset;
542                 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
543                 if (IS_ERR(page))
544                         return PTR_ERR(page);
545                 p = kmap_atomic(page, KM_USER0);
546                 memcpy(buf + copied, p + offset, amt);
547                 kunmap_atomic(p, KM_USER0);
548                 mark_page_accessed(page);
549                 page_cache_release(page);
550                 copied += amt;
551                 index++;
552                 offset = 0;
553         } while(copied < size);
554         (*pos) += size;
555         return size;
556 }
557
558 /**
559  * gfs2_readpages - Read a bunch of pages at once
560  *
561  * Some notes:
562  * 1. This is only for readahead, so we can simply ignore any things
563  *    which are slightly inconvenient (such as locking conflicts between
564  *    the page lock and the glock) and return having done no I/O. Its
565  *    obviously not something we'd want to do on too regular a basis.
566  *    Any I/O we ignore at this time will be done via readpage later.
567  * 2. We don't handle stuffed files here we let readpage do the honours.
568  * 3. mpage_readpages() does most of the heavy lifting in the common case.
569  * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
570  */
571
572 static int gfs2_readpages(struct file *file, struct address_space *mapping,
573                           struct list_head *pages, unsigned nr_pages)
574 {
575         struct inode *inode = mapping->host;
576         struct gfs2_inode *ip = GFS2_I(inode);
577         struct gfs2_sbd *sdp = GFS2_SB(inode);
578         struct gfs2_holder gh;
579         int ret;
580
581         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
582         ret = gfs2_glock_nq(&gh);
583         if (unlikely(ret))
584                 goto out_uninit;
585         if (!gfs2_is_stuffed(ip))
586                 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
587         gfs2_glock_dq(&gh);
588 out_uninit:
589         gfs2_holder_uninit(&gh);
590         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
591                 ret = -EIO;
592         return ret;
593 }
594
595 /**
596  * gfs2_write_begin - Begin to write to a file
597  * @file: The file to write to
598  * @mapping: The mapping in which to write
599  * @pos: The file offset at which to start writing
600  * @len: Length of the write
601  * @flags: Various flags
602  * @pagep: Pointer to return the page
603  * @fsdata: Pointer to return fs data (unused by GFS2)
604  *
605  * Returns: errno
606  */
607
608 static int gfs2_write_begin(struct file *file, struct address_space *mapping,
609                             loff_t pos, unsigned len, unsigned flags,
610                             struct page **pagep, void **fsdata)
611 {
612         struct gfs2_inode *ip = GFS2_I(mapping->host);
613         struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
614         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
615         unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
616         int alloc_required;
617         int error = 0;
618         struct gfs2_alloc *al = NULL;
619         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
620         unsigned from = pos & (PAGE_CACHE_SIZE - 1);
621         struct page *page;
622
623         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
624         error = gfs2_glock_nq(&ip->i_gh);
625         if (unlikely(error))
626                 goto out_uninit;
627         if (&ip->i_inode == sdp->sd_rindex) {
628                 error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
629                                            GL_NOCACHE, &m_ip->i_gh);
630                 if (unlikely(error)) {
631                         gfs2_glock_dq(&ip->i_gh);
632                         goto out_uninit;
633                 }
634         }
635
636         alloc_required = gfs2_write_alloc_required(ip, pos, len);
637
638         if (alloc_required || gfs2_is_jdata(ip))
639                 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
640
641         if (alloc_required) {
642                 al = gfs2_alloc_get(ip);
643                 if (!al) {
644                         error = -ENOMEM;
645                         goto out_unlock;
646                 }
647
648                 error = gfs2_quota_lock_check(ip);
649                 if (error)
650                         goto out_alloc_put;
651
652                 al->al_requested = data_blocks + ind_blocks;
653                 error = gfs2_inplace_reserve(ip);
654                 if (error)
655                         goto out_qunlock;
656         }
657
658         rblocks = RES_DINODE + ind_blocks;
659         if (gfs2_is_jdata(ip))
660                 rblocks += data_blocks ? data_blocks : 1;
661         if (ind_blocks || data_blocks)
662                 rblocks += RES_STATFS + RES_QUOTA;
663         if (&ip->i_inode == sdp->sd_rindex)
664                 rblocks += 2 * RES_STATFS;
665         if (alloc_required)
666                 rblocks += gfs2_rg_blocks(al);
667
668         error = gfs2_trans_begin(sdp, rblocks,
669                                  PAGE_CACHE_SIZE/sdp->sd_sb.sb_bsize);
670         if (error)
671                 goto out_trans_fail;
672
673         error = -ENOMEM;
674         flags |= AOP_FLAG_NOFS;
675         page = grab_cache_page_write_begin(mapping, index, flags);
676         *pagep = page;
677         if (unlikely(!page))
678                 goto out_endtrans;
679
680         if (gfs2_is_stuffed(ip)) {
681                 error = 0;
682                 if (pos + len > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
683                         error = gfs2_unstuff_dinode(ip, page);
684                         if (error == 0)
685                                 goto prepare_write;
686                 } else if (!PageUptodate(page)) {
687                         error = stuffed_readpage(ip, page);
688                 }
689                 goto out;
690         }
691
692 prepare_write:
693         error = __block_write_begin(page, from, len, gfs2_block_map);
694 out:
695         if (error == 0)
696                 return 0;
697
698         unlock_page(page);
699         page_cache_release(page);
700
701         gfs2_trans_end(sdp);
702         if (pos + len > ip->i_inode.i_size)
703                 gfs2_trim_blocks(&ip->i_inode);
704         goto out_trans_fail;
705
706 out_endtrans:
707         gfs2_trans_end(sdp);
708 out_trans_fail:
709         if (alloc_required) {
710                 gfs2_inplace_release(ip);
711 out_qunlock:
712                 gfs2_quota_unlock(ip);
713 out_alloc_put:
714                 gfs2_alloc_put(ip);
715         }
716 out_unlock:
717         if (&ip->i_inode == sdp->sd_rindex) {
718                 gfs2_glock_dq(&m_ip->i_gh);
719                 gfs2_holder_uninit(&m_ip->i_gh);
720         }
721         gfs2_glock_dq(&ip->i_gh);
722 out_uninit:
723         gfs2_holder_uninit(&ip->i_gh);
724         return error;
725 }
726
727 /**
728  * adjust_fs_space - Adjusts the free space available due to gfs2_grow
729  * @inode: the rindex inode
730  */
731 static void adjust_fs_space(struct inode *inode)
732 {
733         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
734         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
735         struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
736         struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
737         struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
738         struct buffer_head *m_bh, *l_bh;
739         u64 fs_total, new_free;
740
741         /* Total up the file system space, according to the latest rindex. */
742         fs_total = gfs2_ri_total(sdp);
743         if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
744                 return;
745
746         spin_lock(&sdp->sd_statfs_spin);
747         gfs2_statfs_change_in(m_sc, m_bh->b_data +
748                               sizeof(struct gfs2_dinode));
749         if (fs_total > (m_sc->sc_total + l_sc->sc_total))
750                 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
751         else
752                 new_free = 0;
753         spin_unlock(&sdp->sd_statfs_spin);
754         fs_warn(sdp, "File system extended by %llu blocks.\n",
755                 (unsigned long long)new_free);
756         gfs2_statfs_change(sdp, new_free, new_free, 0);
757
758         if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
759                 goto out;
760         update_statfs(sdp, m_bh, l_bh);
761         brelse(l_bh);
762 out:
763         brelse(m_bh);
764 }
765
766 /**
767  * gfs2_stuffed_write_end - Write end for stuffed files
768  * @inode: The inode
769  * @dibh: The buffer_head containing the on-disk inode
770  * @pos: The file position
771  * @len: The length of the write
772  * @copied: How much was actually copied by the VFS
773  * @page: The page
774  *
775  * This copies the data from the page into the inode block after
776  * the inode data structure itself.
777  *
778  * Returns: errno
779  */
780 static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
781                                   loff_t pos, unsigned len, unsigned copied,
782                                   struct page *page)
783 {
784         struct gfs2_inode *ip = GFS2_I(inode);
785         struct gfs2_sbd *sdp = GFS2_SB(inode);
786         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
787         u64 to = pos + copied;
788         void *kaddr;
789         unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
790         struct gfs2_dinode *di = (struct gfs2_dinode *)dibh->b_data;
791
792         BUG_ON((pos + len) > (dibh->b_size - sizeof(struct gfs2_dinode)));
793         kaddr = kmap_atomic(page, KM_USER0);
794         memcpy(buf + pos, kaddr + pos, copied);
795         memset(kaddr + pos + copied, 0, len - copied);
796         flush_dcache_page(page);
797         kunmap_atomic(kaddr, KM_USER0);
798
799         if (!PageUptodate(page))
800                 SetPageUptodate(page);
801         unlock_page(page);
802         page_cache_release(page);
803
804         if (copied) {
805                 if (inode->i_size < to)
806                         i_size_write(inode, to);
807                 gfs2_dinode_out(ip, di);
808                 mark_inode_dirty(inode);
809         }
810
811         if (inode == sdp->sd_rindex) {
812                 adjust_fs_space(inode);
813                 ip->i_gh.gh_flags |= GL_NOCACHE;
814         }
815
816         brelse(dibh);
817         gfs2_trans_end(sdp);
818         if (inode == sdp->sd_rindex) {
819                 gfs2_glock_dq(&m_ip->i_gh);
820                 gfs2_holder_uninit(&m_ip->i_gh);
821         }
822         gfs2_glock_dq(&ip->i_gh);
823         gfs2_holder_uninit(&ip->i_gh);
824         return copied;
825 }
826
827 /**
828  * gfs2_write_end
829  * @file: The file to write to
830  * @mapping: The address space to write to
831  * @pos: The file position
832  * @len: The length of the data
833  * @copied:
834  * @page: The page that has been written
835  * @fsdata: The fsdata (unused in GFS2)
836  *
837  * The main write_end function for GFS2. We have a separate one for
838  * stuffed files as they are slightly different, otherwise we just
839  * put our locking around the VFS provided functions.
840  *
841  * Returns: errno
842  */
843
844 static int gfs2_write_end(struct file *file, struct address_space *mapping,
845                           loff_t pos, unsigned len, unsigned copied,
846                           struct page *page, void *fsdata)
847 {
848         struct inode *inode = page->mapping->host;
849         struct gfs2_inode *ip = GFS2_I(inode);
850         struct gfs2_sbd *sdp = GFS2_SB(inode);
851         struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
852         struct buffer_head *dibh;
853         struct gfs2_alloc *al = ip->i_alloc;
854         unsigned int from = pos & (PAGE_CACHE_SIZE - 1);
855         unsigned int to = from + len;
856         int ret;
857
858         BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
859
860         ret = gfs2_meta_inode_buffer(ip, &dibh);
861         if (unlikely(ret)) {
862                 unlock_page(page);
863                 page_cache_release(page);
864                 goto failed;
865         }
866
867         gfs2_trans_add_bh(ip->i_gl, dibh, 1);
868
869         if (gfs2_is_stuffed(ip))
870                 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
871
872         if (!gfs2_is_writeback(ip))
873                 gfs2_page_add_databufs(ip, page, from, to);
874
875         ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
876         if (ret > 0) {
877                 gfs2_dinode_out(ip, dibh->b_data);
878                 mark_inode_dirty(inode);
879         }
880
881         if (inode == sdp->sd_rindex) {
882                 adjust_fs_space(inode);
883                 ip->i_gh.gh_flags |= GL_NOCACHE;
884         }
885
886         brelse(dibh);
887 failed:
888         gfs2_trans_end(sdp);
889         if (al) {
890                 gfs2_inplace_release(ip);
891                 gfs2_quota_unlock(ip);
892                 gfs2_alloc_put(ip);
893         }
894         if (inode == sdp->sd_rindex) {
895                 gfs2_glock_dq(&m_ip->i_gh);
896                 gfs2_holder_uninit(&m_ip->i_gh);
897         }
898         gfs2_glock_dq(&ip->i_gh);
899         gfs2_holder_uninit(&ip->i_gh);
900         return ret;
901 }
902
903 /**
904  * gfs2_set_page_dirty - Page dirtying function
905  * @page: The page to dirty
906  *
907  * Returns: 1 if it dirtyed the page, or 0 otherwise
908  */
909  
910 static int gfs2_set_page_dirty(struct page *page)
911 {
912         SetPageChecked(page);
913         return __set_page_dirty_buffers(page);
914 }
915
916 /**
917  * gfs2_bmap - Block map function
918  * @mapping: Address space info
919  * @lblock: The block to map
920  *
921  * Returns: The disk address for the block or 0 on hole or error
922  */
923
924 static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
925 {
926         struct gfs2_inode *ip = GFS2_I(mapping->host);
927         struct gfs2_holder i_gh;
928         sector_t dblock = 0;
929         int error;
930
931         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
932         if (error)
933                 return 0;
934
935         if (!gfs2_is_stuffed(ip))
936                 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map);
937
938         gfs2_glock_dq_uninit(&i_gh);
939
940         return dblock;
941 }
942
943 static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
944 {
945         struct gfs2_bufdata *bd;
946
947         lock_buffer(bh);
948         gfs2_log_lock(sdp);
949         clear_buffer_dirty(bh);
950         bd = bh->b_private;
951         if (bd) {
952                 if (!list_empty(&bd->bd_le.le_list) && !buffer_pinned(bh))
953                         list_del_init(&bd->bd_le.le_list);
954                 else
955                         gfs2_remove_from_journal(bh, current->journal_info, 0);
956         }
957         bh->b_bdev = NULL;
958         clear_buffer_mapped(bh);
959         clear_buffer_req(bh);
960         clear_buffer_new(bh);
961         gfs2_log_unlock(sdp);
962         unlock_buffer(bh);
963 }
964
965 static void gfs2_invalidatepage(struct page *page, unsigned long offset)
966 {
967         struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
968         struct buffer_head *bh, *head;
969         unsigned long pos = 0;
970
971         BUG_ON(!PageLocked(page));
972         if (offset == 0)
973                 ClearPageChecked(page);
974         if (!page_has_buffers(page))
975                 goto out;
976
977         bh = head = page_buffers(page);
978         do {
979                 if (offset <= pos)
980                         gfs2_discard(sdp, bh);
981                 pos += bh->b_size;
982                 bh = bh->b_this_page;
983         } while (bh != head);
984 out:
985         if (offset == 0)
986                 try_to_release_page(page, 0);
987 }
988
989 /**
990  * gfs2_ok_for_dio - check that dio is valid on this file
991  * @ip: The inode
992  * @rw: READ or WRITE
993  * @offset: The offset at which we are reading or writing
994  *
995  * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
996  *          1 (to accept the i/o request)
997  */
998 static int gfs2_ok_for_dio(struct gfs2_inode *ip, int rw, loff_t offset)
999 {
1000         /*
1001          * Should we return an error here? I can't see that O_DIRECT for
1002          * a stuffed file makes any sense. For now we'll silently fall
1003          * back to buffered I/O
1004          */
1005         if (gfs2_is_stuffed(ip))
1006                 return 0;
1007
1008         if (offset >= i_size_read(&ip->i_inode))
1009                 return 0;
1010         return 1;
1011 }
1012
1013
1014
1015 static ssize_t gfs2_direct_IO(int rw, struct kiocb *iocb,
1016                               const struct iovec *iov, loff_t offset,
1017                               unsigned long nr_segs)
1018 {
1019         struct file *file = iocb->ki_filp;
1020         struct inode *inode = file->f_mapping->host;
1021         struct gfs2_inode *ip = GFS2_I(inode);
1022         struct gfs2_holder gh;
1023         int rv;
1024
1025         /*
1026          * Deferred lock, even if its a write, since we do no allocation
1027          * on this path. All we need change is atime, and this lock mode
1028          * ensures that other nodes have flushed their buffered read caches
1029          * (i.e. their page cache entries for this inode). We do not,
1030          * unfortunately have the option of only flushing a range like
1031          * the VFS does.
1032          */
1033         gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
1034         rv = gfs2_glock_nq(&gh);
1035         if (rv)
1036                 return rv;
1037         rv = gfs2_ok_for_dio(ip, rw, offset);
1038         if (rv != 1)
1039                 goto out; /* dio not valid, fall back to buffered i/o */
1040
1041         rv = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
1042                                   offset, nr_segs, gfs2_get_block_direct,
1043                                   NULL, NULL, 0);
1044 out:
1045         gfs2_glock_dq_m(1, &gh);
1046         gfs2_holder_uninit(&gh);
1047         return rv;
1048 }
1049
1050 /**
1051  * gfs2_releasepage - free the metadata associated with a page
1052  * @page: the page that's being released
1053  * @gfp_mask: passed from Linux VFS, ignored by us
1054  *
1055  * Call try_to_free_buffers() if the buffers in this page can be
1056  * released.
1057  *
1058  * Returns: 0
1059  */
1060
1061 int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
1062 {
1063         struct address_space *mapping = page->mapping;
1064         struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
1065         struct buffer_head *bh, *head;
1066         struct gfs2_bufdata *bd;
1067
1068         if (!page_has_buffers(page))
1069                 return 0;
1070
1071         gfs2_log_lock(sdp);
1072         spin_lock(&sdp->sd_ail_lock);
1073         head = bh = page_buffers(page);
1074         do {
1075                 if (atomic_read(&bh->b_count))
1076                         goto cannot_release;
1077                 bd = bh->b_private;
1078                 if (bd && bd->bd_ail)
1079                         goto cannot_release;
1080                 if (buffer_pinned(bh) || buffer_dirty(bh))
1081                         goto not_possible;
1082                 bh = bh->b_this_page;
1083         } while(bh != head);
1084         spin_unlock(&sdp->sd_ail_lock);
1085         gfs2_log_unlock(sdp);
1086
1087         head = bh = page_buffers(page);
1088         do {
1089                 gfs2_log_lock(sdp);
1090                 bd = bh->b_private;
1091                 if (bd) {
1092                         gfs2_assert_warn(sdp, bd->bd_bh == bh);
1093                         gfs2_assert_warn(sdp, list_empty(&bd->bd_list_tr));
1094                         if (!list_empty(&bd->bd_le.le_list)) {
1095                                 if (!buffer_pinned(bh))
1096                                         list_del_init(&bd->bd_le.le_list);
1097                                 else
1098                                         bd = NULL;
1099                         }
1100                         if (bd)
1101                                 bd->bd_bh = NULL;
1102                         bh->b_private = NULL;
1103                 }
1104                 gfs2_log_unlock(sdp);
1105                 if (bd)
1106                         kmem_cache_free(gfs2_bufdata_cachep, bd);
1107
1108                 bh = bh->b_this_page;
1109         } while (bh != head);
1110
1111         return try_to_free_buffers(page);
1112
1113 not_possible: /* Should never happen */
1114         WARN_ON(buffer_dirty(bh));
1115         WARN_ON(buffer_pinned(bh));
1116 cannot_release:
1117         spin_unlock(&sdp->sd_ail_lock);
1118         gfs2_log_unlock(sdp);
1119         return 0;
1120 }
1121
1122 static const struct address_space_operations gfs2_writeback_aops = {
1123         .writepage = gfs2_writeback_writepage,
1124         .writepages = gfs2_writeback_writepages,
1125         .readpage = gfs2_readpage,
1126         .readpages = gfs2_readpages,
1127         .write_begin = gfs2_write_begin,
1128         .write_end = gfs2_write_end,
1129         .bmap = gfs2_bmap,
1130         .invalidatepage = gfs2_invalidatepage,
1131         .releasepage = gfs2_releasepage,
1132         .direct_IO = gfs2_direct_IO,
1133         .migratepage = buffer_migrate_page,
1134         .is_partially_uptodate = block_is_partially_uptodate,
1135         .error_remove_page = generic_error_remove_page,
1136 };
1137
1138 static const struct address_space_operations gfs2_ordered_aops = {
1139         .writepage = gfs2_ordered_writepage,
1140         .readpage = gfs2_readpage,
1141         .readpages = gfs2_readpages,
1142         .write_begin = gfs2_write_begin,
1143         .write_end = gfs2_write_end,
1144         .set_page_dirty = gfs2_set_page_dirty,
1145         .bmap = gfs2_bmap,
1146         .invalidatepage = gfs2_invalidatepage,
1147         .releasepage = gfs2_releasepage,
1148         .direct_IO = gfs2_direct_IO,
1149         .migratepage = buffer_migrate_page,
1150         .is_partially_uptodate = block_is_partially_uptodate,
1151         .error_remove_page = generic_error_remove_page,
1152 };
1153
1154 static const struct address_space_operations gfs2_jdata_aops = {
1155         .writepage = gfs2_jdata_writepage,
1156         .writepages = gfs2_jdata_writepages,
1157         .readpage = gfs2_readpage,
1158         .readpages = gfs2_readpages,
1159         .write_begin = gfs2_write_begin,
1160         .write_end = gfs2_write_end,
1161         .set_page_dirty = gfs2_set_page_dirty,
1162         .bmap = gfs2_bmap,
1163         .invalidatepage = gfs2_invalidatepage,
1164         .releasepage = gfs2_releasepage,
1165         .is_partially_uptodate = block_is_partially_uptodate,
1166         .error_remove_page = generic_error_remove_page,
1167 };
1168
1169 void gfs2_set_aops(struct inode *inode)
1170 {
1171         struct gfs2_inode *ip = GFS2_I(inode);
1172
1173         if (gfs2_is_writeback(ip))
1174                 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1175         else if (gfs2_is_ordered(ip))
1176                 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1177         else if (gfs2_is_jdata(ip))
1178                 inode->i_mapping->a_ops = &gfs2_jdata_aops;
1179         else
1180                 BUG();
1181 }
1182