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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
39void 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
68static 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
81static 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
95static 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;
116redirty:
117 redirty_page_for_writepage(wbc, page);
118out:
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
130static 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
149static 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
179static 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
204static 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
226out_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 */
241static 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
258static 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
329static 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
353retry:
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
392static 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
415static 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
462static 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
491static 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);
510out:
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
527int 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
572static 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);
588out_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
608static 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
692prepare_write:
693 error = __block_write_begin(page, from, len, gfs2_block_map);
694out:
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
706out_endtrans:
707 gfs2_trans_end(sdp);
708out_trans_fail:
709 if (alloc_required) {
710 gfs2_inplace_release(ip);
711out_qunlock:
712 gfs2_quota_unlock(ip);
713out_alloc_put:
714 gfs2_alloc_put(ip);
715 }
716out_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);
722out_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 */
731static 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);
762out:
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 */
780static 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
844static 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);
887failed:
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
910static 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
924static 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
943static 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
965static 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);
984out:
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 */
998static 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
1015static 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);
1044out:
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
1061int 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
1113not_possible: /* Should never happen */
1114 WARN_ON(buffer_dirty(bh));
1115 WARN_ON(buffer_pinned(bh));
1116cannot_release:
1117 spin_unlock(&sdp->sd_ail_lock);
1118 gfs2_log_unlock(sdp);
1119 return 0;
1120}
1121
1122static 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
1138static 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
1154static 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
1169void 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
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#include <linux/uio.h>
24#include <trace/events/writeback.h>
25
26#include "gfs2.h"
27#include "incore.h"
28#include "bmap.h"
29#include "glock.h"
30#include "inode.h"
31#include "log.h"
32#include "meta_io.h"
33#include "quota.h"
34#include "trans.h"
35#include "rgrp.h"
36#include "super.h"
37#include "util.h"
38#include "glops.h"
39
40
41static void gfs2_page_add_databufs(struct gfs2_inode *ip, struct page *page,
42 unsigned int from, unsigned int len)
43{
44 struct buffer_head *head = page_buffers(page);
45 unsigned int bsize = head->b_size;
46 struct buffer_head *bh;
47 unsigned int to = from + len;
48 unsigned int start, end;
49
50 for (bh = head, start = 0; bh != head || !start;
51 bh = bh->b_this_page, start = end) {
52 end = start + bsize;
53 if (end <= from)
54 continue;
55 if (start >= to)
56 break;
57 if (gfs2_is_jdata(ip))
58 set_buffer_uptodate(bh);
59 gfs2_trans_add_data(ip->i_gl, bh);
60 }
61}
62
63/**
64 * gfs2_get_block_noalloc - Fills in a buffer head with details about a block
65 * @inode: The inode
66 * @lblock: The block number to look up
67 * @bh_result: The buffer head to return the result in
68 * @create: Non-zero if we may add block to the file
69 *
70 * Returns: errno
71 */
72
73static int gfs2_get_block_noalloc(struct inode *inode, sector_t lblock,
74 struct buffer_head *bh_result, int create)
75{
76 int error;
77
78 error = gfs2_block_map(inode, lblock, bh_result, 0);
79 if (error)
80 return error;
81 if (!buffer_mapped(bh_result))
82 return -EIO;
83 return 0;
84}
85
86static int gfs2_get_block_direct(struct inode *inode, sector_t lblock,
87 struct buffer_head *bh_result, int create)
88{
89 return gfs2_block_map(inode, lblock, bh_result, 0);
90}
91
92/**
93 * gfs2_writepage_common - Common bits of writepage
94 * @page: The page to be written
95 * @wbc: The writeback control
96 *
97 * Returns: 1 if writepage is ok, otherwise an error code or zero if no error.
98 */
99
100static int gfs2_writepage_common(struct page *page,
101 struct writeback_control *wbc)
102{
103 struct inode *inode = page->mapping->host;
104 struct gfs2_inode *ip = GFS2_I(inode);
105 struct gfs2_sbd *sdp = GFS2_SB(inode);
106 loff_t i_size = i_size_read(inode);
107 pgoff_t end_index = i_size >> PAGE_SHIFT;
108 unsigned offset;
109
110 if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
111 goto out;
112 if (current->journal_info)
113 goto redirty;
114 /* Is the page fully outside i_size? (truncate in progress) */
115 offset = i_size & (PAGE_SIZE-1);
116 if (page->index > end_index || (page->index == end_index && !offset)) {
117 page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
118 goto out;
119 }
120 return 1;
121redirty:
122 redirty_page_for_writepage(wbc, page);
123out:
124 unlock_page(page);
125 return 0;
126}
127
128/**
129 * gfs2_writepage - Write page for writeback mappings
130 * @page: The page
131 * @wbc: The writeback control
132 *
133 */
134
135static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
136{
137 int ret;
138
139 ret = gfs2_writepage_common(page, wbc);
140 if (ret <= 0)
141 return ret;
142
143 return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
144}
145
146/* This is the same as calling block_write_full_page, but it also
147 * writes pages outside of i_size
148 */
149static int gfs2_write_full_page(struct page *page, get_block_t *get_block,
150 struct writeback_control *wbc)
151{
152 struct inode * const inode = page->mapping->host;
153 loff_t i_size = i_size_read(inode);
154 const pgoff_t end_index = i_size >> PAGE_SHIFT;
155 unsigned offset;
156
157 /*
158 * The page straddles i_size. It must be zeroed out on each and every
159 * writepage invocation because it may be mmapped. "A file is mapped
160 * in multiples of the page size. For a file that is not a multiple of
161 * the page size, the remaining memory is zeroed when mapped, and
162 * writes to that region are not written out to the file."
163 */
164 offset = i_size & (PAGE_SIZE-1);
165 if (page->index == end_index && offset)
166 zero_user_segment(page, offset, PAGE_SIZE);
167
168 return __block_write_full_page(inode, page, get_block, wbc,
169 end_buffer_async_write);
170}
171
172/**
173 * __gfs2_jdata_writepage - The core of jdata writepage
174 * @page: The page to write
175 * @wbc: The writeback control
176 *
177 * This is shared between writepage and writepages and implements the
178 * core of the writepage operation. If a transaction is required then
179 * PageChecked will have been set and the transaction will have
180 * already been started before this is called.
181 */
182
183static int __gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
184{
185 struct inode *inode = page->mapping->host;
186 struct gfs2_inode *ip = GFS2_I(inode);
187 struct gfs2_sbd *sdp = GFS2_SB(inode);
188
189 if (PageChecked(page)) {
190 ClearPageChecked(page);
191 if (!page_has_buffers(page)) {
192 create_empty_buffers(page, inode->i_sb->s_blocksize,
193 BIT(BH_Dirty)|BIT(BH_Uptodate));
194 }
195 gfs2_page_add_databufs(ip, page, 0, sdp->sd_vfs->s_blocksize);
196 }
197 return gfs2_write_full_page(page, gfs2_get_block_noalloc, wbc);
198}
199
200/**
201 * gfs2_jdata_writepage - Write complete page
202 * @page: Page to write
203 * @wbc: The writeback control
204 *
205 * Returns: errno
206 *
207 */
208
209static int gfs2_jdata_writepage(struct page *page, struct writeback_control *wbc)
210{
211 struct inode *inode = page->mapping->host;
212 struct gfs2_inode *ip = GFS2_I(inode);
213 struct gfs2_sbd *sdp = GFS2_SB(inode);
214 int ret;
215
216 if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
217 goto out;
218 if (PageChecked(page) || current->journal_info)
219 goto out_ignore;
220 ret = __gfs2_jdata_writepage(page, wbc);
221 return ret;
222
223out_ignore:
224 redirty_page_for_writepage(wbc, page);
225out:
226 unlock_page(page);
227 return 0;
228}
229
230/**
231 * gfs2_writepages - Write a bunch of dirty pages back to disk
232 * @mapping: The mapping to write
233 * @wbc: Write-back control
234 *
235 * Used for both ordered and writeback modes.
236 */
237static int gfs2_writepages(struct address_space *mapping,
238 struct writeback_control *wbc)
239{
240 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
241 int ret = mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
242
243 /*
244 * Even if we didn't write any pages here, we might still be holding
245 * dirty pages in the ail. We forcibly flush the ail because we don't
246 * want balance_dirty_pages() to loop indefinitely trying to write out
247 * pages held in the ail that it can't find.
248 */
249 if (ret == 0)
250 set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
251
252 return ret;
253}
254
255/**
256 * gfs2_write_jdata_pagevec - Write back a pagevec's worth of pages
257 * @mapping: The mapping
258 * @wbc: The writeback control
259 * @pvec: The vector of pages
260 * @nr_pages: The number of pages to write
261 * @done_index: Page index
262 *
263 * Returns: non-zero if loop should terminate, zero otherwise
264 */
265
266static int gfs2_write_jdata_pagevec(struct address_space *mapping,
267 struct writeback_control *wbc,
268 struct pagevec *pvec,
269 int nr_pages,
270 pgoff_t *done_index)
271{
272 struct inode *inode = mapping->host;
273 struct gfs2_sbd *sdp = GFS2_SB(inode);
274 unsigned nrblocks = nr_pages * (PAGE_SIZE/inode->i_sb->s_blocksize);
275 int i;
276 int ret;
277
278 ret = gfs2_trans_begin(sdp, nrblocks, nrblocks);
279 if (ret < 0)
280 return ret;
281
282 for(i = 0; i < nr_pages; i++) {
283 struct page *page = pvec->pages[i];
284
285 *done_index = page->index;
286
287 lock_page(page);
288
289 if (unlikely(page->mapping != mapping)) {
290continue_unlock:
291 unlock_page(page);
292 continue;
293 }
294
295 if (!PageDirty(page)) {
296 /* someone wrote it for us */
297 goto continue_unlock;
298 }
299
300 if (PageWriteback(page)) {
301 if (wbc->sync_mode != WB_SYNC_NONE)
302 wait_on_page_writeback(page);
303 else
304 goto continue_unlock;
305 }
306
307 BUG_ON(PageWriteback(page));
308 if (!clear_page_dirty_for_io(page))
309 goto continue_unlock;
310
311 trace_wbc_writepage(wbc, inode_to_bdi(inode));
312
313 ret = __gfs2_jdata_writepage(page, wbc);
314 if (unlikely(ret)) {
315 if (ret == AOP_WRITEPAGE_ACTIVATE) {
316 unlock_page(page);
317 ret = 0;
318 } else {
319
320 /*
321 * done_index is set past this page,
322 * so media errors will not choke
323 * background writeout for the entire
324 * file. This has consequences for
325 * range_cyclic semantics (ie. it may
326 * not be suitable for data integrity
327 * writeout).
328 */
329 *done_index = page->index + 1;
330 ret = 1;
331 break;
332 }
333 }
334
335 /*
336 * We stop writing back only if we are not doing
337 * integrity sync. In case of integrity sync we have to
338 * keep going until we have written all the pages
339 * we tagged for writeback prior to entering this loop.
340 */
341 if (--wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) {
342 ret = 1;
343 break;
344 }
345
346 }
347 gfs2_trans_end(sdp);
348 return ret;
349}
350
351/**
352 * gfs2_write_cache_jdata - Like write_cache_pages but different
353 * @mapping: The mapping to write
354 * @wbc: The writeback control
355 *
356 * The reason that we use our own function here is that we need to
357 * start transactions before we grab page locks. This allows us
358 * to get the ordering right.
359 */
360
361static int gfs2_write_cache_jdata(struct address_space *mapping,
362 struct writeback_control *wbc)
363{
364 int ret = 0;
365 int done = 0;
366 struct pagevec pvec;
367 int nr_pages;
368 pgoff_t uninitialized_var(writeback_index);
369 pgoff_t index;
370 pgoff_t end;
371 pgoff_t done_index;
372 int cycled;
373 int range_whole = 0;
374 int tag;
375
376 pagevec_init(&pvec);
377 if (wbc->range_cyclic) {
378 writeback_index = mapping->writeback_index; /* prev offset */
379 index = writeback_index;
380 if (index == 0)
381 cycled = 1;
382 else
383 cycled = 0;
384 end = -1;
385 } else {
386 index = wbc->range_start >> PAGE_SHIFT;
387 end = wbc->range_end >> PAGE_SHIFT;
388 if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
389 range_whole = 1;
390 cycled = 1; /* ignore range_cyclic tests */
391 }
392 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
393 tag = PAGECACHE_TAG_TOWRITE;
394 else
395 tag = PAGECACHE_TAG_DIRTY;
396
397retry:
398 if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
399 tag_pages_for_writeback(mapping, index, end);
400 done_index = index;
401 while (!done && (index <= end)) {
402 nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
403 tag);
404 if (nr_pages == 0)
405 break;
406
407 ret = gfs2_write_jdata_pagevec(mapping, wbc, &pvec, nr_pages, &done_index);
408 if (ret)
409 done = 1;
410 if (ret > 0)
411 ret = 0;
412 pagevec_release(&pvec);
413 cond_resched();
414 }
415
416 if (!cycled && !done) {
417 /*
418 * range_cyclic:
419 * We hit the last page and there is more work to be done: wrap
420 * back to the start of the file
421 */
422 cycled = 1;
423 index = 0;
424 end = writeback_index - 1;
425 goto retry;
426 }
427
428 if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
429 mapping->writeback_index = done_index;
430
431 return ret;
432}
433
434
435/**
436 * gfs2_jdata_writepages - Write a bunch of dirty pages back to disk
437 * @mapping: The mapping to write
438 * @wbc: The writeback control
439 *
440 */
441
442static int gfs2_jdata_writepages(struct address_space *mapping,
443 struct writeback_control *wbc)
444{
445 struct gfs2_inode *ip = GFS2_I(mapping->host);
446 struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
447 int ret;
448
449 ret = gfs2_write_cache_jdata(mapping, wbc);
450 if (ret == 0 && wbc->sync_mode == WB_SYNC_ALL) {
451 gfs2_log_flush(sdp, ip->i_gl, GFS2_LOG_HEAD_FLUSH_NORMAL |
452 GFS2_LFC_JDATA_WPAGES);
453 ret = gfs2_write_cache_jdata(mapping, wbc);
454 }
455 return ret;
456}
457
458/**
459 * stuffed_readpage - Fill in a Linux page with stuffed file data
460 * @ip: the inode
461 * @page: the page
462 *
463 * Returns: errno
464 */
465
466static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
467{
468 struct buffer_head *dibh;
469 u64 dsize = i_size_read(&ip->i_inode);
470 void *kaddr;
471 int error;
472
473 /*
474 * Due to the order of unstuffing files and ->fault(), we can be
475 * asked for a zero page in the case of a stuffed file being extended,
476 * so we need to supply one here. It doesn't happen often.
477 */
478 if (unlikely(page->index)) {
479 zero_user(page, 0, PAGE_SIZE);
480 SetPageUptodate(page);
481 return 0;
482 }
483
484 error = gfs2_meta_inode_buffer(ip, &dibh);
485 if (error)
486 return error;
487
488 kaddr = kmap_atomic(page);
489 if (dsize > gfs2_max_stuffed_size(ip))
490 dsize = gfs2_max_stuffed_size(ip);
491 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
492 memset(kaddr + dsize, 0, PAGE_SIZE - dsize);
493 kunmap_atomic(kaddr);
494 flush_dcache_page(page);
495 brelse(dibh);
496 SetPageUptodate(page);
497
498 return 0;
499}
500
501
502/**
503 * __gfs2_readpage - readpage
504 * @file: The file to read a page for
505 * @page: The page to read
506 *
507 * This is the core of gfs2's readpage. It's used by the internal file
508 * reading code as in that case we already hold the glock. Also it's
509 * called by gfs2_readpage() once the required lock has been granted.
510 */
511
512static int __gfs2_readpage(void *file, struct page *page)
513{
514 struct gfs2_inode *ip = GFS2_I(page->mapping->host);
515 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
516 int error;
517
518 if (gfs2_is_stuffed(ip)) {
519 error = stuffed_readpage(ip, page);
520 unlock_page(page);
521 } else {
522 error = mpage_readpage(page, gfs2_block_map);
523 }
524
525 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
526 return -EIO;
527
528 return error;
529}
530
531/**
532 * gfs2_readpage - read a page of a file
533 * @file: The file to read
534 * @page: The page of the file
535 *
536 * This deals with the locking required. We have to unlock and
537 * relock the page in order to get the locking in the right
538 * order.
539 */
540
541static int gfs2_readpage(struct file *file, struct page *page)
542{
543 struct address_space *mapping = page->mapping;
544 struct gfs2_inode *ip = GFS2_I(mapping->host);
545 struct gfs2_holder gh;
546 int error;
547
548 unlock_page(page);
549 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
550 error = gfs2_glock_nq(&gh);
551 if (unlikely(error))
552 goto out;
553 error = AOP_TRUNCATED_PAGE;
554 lock_page(page);
555 if (page->mapping == mapping && !PageUptodate(page))
556 error = __gfs2_readpage(file, page);
557 else
558 unlock_page(page);
559 gfs2_glock_dq(&gh);
560out:
561 gfs2_holder_uninit(&gh);
562 if (error && error != AOP_TRUNCATED_PAGE)
563 lock_page(page);
564 return error;
565}
566
567/**
568 * gfs2_internal_read - read an internal file
569 * @ip: The gfs2 inode
570 * @buf: The buffer to fill
571 * @pos: The file position
572 * @size: The amount to read
573 *
574 */
575
576int gfs2_internal_read(struct gfs2_inode *ip, char *buf, loff_t *pos,
577 unsigned size)
578{
579 struct address_space *mapping = ip->i_inode.i_mapping;
580 unsigned long index = *pos / PAGE_SIZE;
581 unsigned offset = *pos & (PAGE_SIZE - 1);
582 unsigned copied = 0;
583 unsigned amt;
584 struct page *page;
585 void *p;
586
587 do {
588 amt = size - copied;
589 if (offset + size > PAGE_SIZE)
590 amt = PAGE_SIZE - offset;
591 page = read_cache_page(mapping, index, __gfs2_readpage, NULL);
592 if (IS_ERR(page))
593 return PTR_ERR(page);
594 p = kmap_atomic(page);
595 memcpy(buf + copied, p + offset, amt);
596 kunmap_atomic(p);
597 put_page(page);
598 copied += amt;
599 index++;
600 offset = 0;
601 } while(copied < size);
602 (*pos) += size;
603 return size;
604}
605
606/**
607 * gfs2_readpages - Read a bunch of pages at once
608 * @file: The file to read from
609 * @mapping: Address space info
610 * @pages: List of pages to read
611 * @nr_pages: Number of pages to read
612 *
613 * Some notes:
614 * 1. This is only for readahead, so we can simply ignore any things
615 * which are slightly inconvenient (such as locking conflicts between
616 * the page lock and the glock) and return having done no I/O. Its
617 * obviously not something we'd want to do on too regular a basis.
618 * Any I/O we ignore at this time will be done via readpage later.
619 * 2. We don't handle stuffed files here we let readpage do the honours.
620 * 3. mpage_readpages() does most of the heavy lifting in the common case.
621 * 4. gfs2_block_map() is relied upon to set BH_Boundary in the right places.
622 */
623
624static int gfs2_readpages(struct file *file, struct address_space *mapping,
625 struct list_head *pages, unsigned nr_pages)
626{
627 struct inode *inode = mapping->host;
628 struct gfs2_inode *ip = GFS2_I(inode);
629 struct gfs2_sbd *sdp = GFS2_SB(inode);
630 struct gfs2_holder gh;
631 int ret;
632
633 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
634 ret = gfs2_glock_nq(&gh);
635 if (unlikely(ret))
636 goto out_uninit;
637 if (!gfs2_is_stuffed(ip))
638 ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
639 gfs2_glock_dq(&gh);
640out_uninit:
641 gfs2_holder_uninit(&gh);
642 if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
643 ret = -EIO;
644 return ret;
645}
646
647/**
648 * gfs2_write_begin - Begin to write to a file
649 * @file: The file to write to
650 * @mapping: The mapping in which to write
651 * @pos: The file offset at which to start writing
652 * @len: Length of the write
653 * @flags: Various flags
654 * @pagep: Pointer to return the page
655 * @fsdata: Pointer to return fs data (unused by GFS2)
656 *
657 * Returns: errno
658 */
659
660static int gfs2_write_begin(struct file *file, struct address_space *mapping,
661 loff_t pos, unsigned len, unsigned flags,
662 struct page **pagep, void **fsdata)
663{
664 struct gfs2_inode *ip = GFS2_I(mapping->host);
665 struct gfs2_sbd *sdp = GFS2_SB(mapping->host);
666 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
667 unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
668 unsigned requested = 0;
669 int alloc_required;
670 int error = 0;
671 pgoff_t index = pos >> PAGE_SHIFT;
672 unsigned from = pos & (PAGE_SIZE - 1);
673 struct page *page;
674
675 gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
676 error = gfs2_glock_nq(&ip->i_gh);
677 if (unlikely(error))
678 goto out_uninit;
679 if (&ip->i_inode == sdp->sd_rindex) {
680 error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE,
681 GL_NOCACHE, &m_ip->i_gh);
682 if (unlikely(error)) {
683 gfs2_glock_dq(&ip->i_gh);
684 goto out_uninit;
685 }
686 }
687
688 alloc_required = gfs2_write_alloc_required(ip, pos, len);
689
690 if (alloc_required || gfs2_is_jdata(ip))
691 gfs2_write_calc_reserv(ip, len, &data_blocks, &ind_blocks);
692
693 if (alloc_required) {
694 struct gfs2_alloc_parms ap = { .aflags = 0, };
695 requested = data_blocks + ind_blocks;
696 ap.target = requested;
697 error = gfs2_quota_lock_check(ip, &ap);
698 if (error)
699 goto out_unlock;
700
701 error = gfs2_inplace_reserve(ip, &ap);
702 if (error)
703 goto out_qunlock;
704 }
705
706 rblocks = RES_DINODE + ind_blocks;
707 if (gfs2_is_jdata(ip))
708 rblocks += data_blocks ? data_blocks : 1;
709 if (ind_blocks || data_blocks)
710 rblocks += RES_STATFS + RES_QUOTA;
711 if (&ip->i_inode == sdp->sd_rindex)
712 rblocks += 2 * RES_STATFS;
713 if (alloc_required)
714 rblocks += gfs2_rg_blocks(ip, requested);
715
716 error = gfs2_trans_begin(sdp, rblocks,
717 PAGE_SIZE/sdp->sd_sb.sb_bsize);
718 if (error)
719 goto out_trans_fail;
720
721 error = -ENOMEM;
722 flags |= AOP_FLAG_NOFS;
723 page = grab_cache_page_write_begin(mapping, index, flags);
724 *pagep = page;
725 if (unlikely(!page))
726 goto out_endtrans;
727
728 if (gfs2_is_stuffed(ip)) {
729 error = 0;
730 if (pos + len > gfs2_max_stuffed_size(ip)) {
731 error = gfs2_unstuff_dinode(ip, page);
732 if (error == 0)
733 goto prepare_write;
734 } else if (!PageUptodate(page)) {
735 error = stuffed_readpage(ip, page);
736 }
737 goto out;
738 }
739
740prepare_write:
741 error = __block_write_begin(page, from, len, gfs2_block_map);
742out:
743 if (error == 0)
744 return 0;
745
746 unlock_page(page);
747 put_page(page);
748
749 gfs2_trans_end(sdp);
750 if (pos + len > ip->i_inode.i_size)
751 gfs2_trim_blocks(&ip->i_inode);
752 goto out_trans_fail;
753
754out_endtrans:
755 gfs2_trans_end(sdp);
756out_trans_fail:
757 if (alloc_required) {
758 gfs2_inplace_release(ip);
759out_qunlock:
760 gfs2_quota_unlock(ip);
761 }
762out_unlock:
763 if (&ip->i_inode == sdp->sd_rindex) {
764 gfs2_glock_dq(&m_ip->i_gh);
765 gfs2_holder_uninit(&m_ip->i_gh);
766 }
767 gfs2_glock_dq(&ip->i_gh);
768out_uninit:
769 gfs2_holder_uninit(&ip->i_gh);
770 return error;
771}
772
773/**
774 * adjust_fs_space - Adjusts the free space available due to gfs2_grow
775 * @inode: the rindex inode
776 */
777static void adjust_fs_space(struct inode *inode)
778{
779 struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
780 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
781 struct gfs2_inode *l_ip = GFS2_I(sdp->sd_sc_inode);
782 struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
783 struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;
784 struct buffer_head *m_bh, *l_bh;
785 u64 fs_total, new_free;
786
787 /* Total up the file system space, according to the latest rindex. */
788 fs_total = gfs2_ri_total(sdp);
789 if (gfs2_meta_inode_buffer(m_ip, &m_bh) != 0)
790 return;
791
792 spin_lock(&sdp->sd_statfs_spin);
793 gfs2_statfs_change_in(m_sc, m_bh->b_data +
794 sizeof(struct gfs2_dinode));
795 if (fs_total > (m_sc->sc_total + l_sc->sc_total))
796 new_free = fs_total - (m_sc->sc_total + l_sc->sc_total);
797 else
798 new_free = 0;
799 spin_unlock(&sdp->sd_statfs_spin);
800 fs_warn(sdp, "File system extended by %llu blocks.\n",
801 (unsigned long long)new_free);
802 gfs2_statfs_change(sdp, new_free, new_free, 0);
803
804 if (gfs2_meta_inode_buffer(l_ip, &l_bh) != 0)
805 goto out;
806 update_statfs(sdp, m_bh, l_bh);
807 brelse(l_bh);
808out:
809 brelse(m_bh);
810}
811
812/**
813 * gfs2_stuffed_write_end - Write end for stuffed files
814 * @inode: The inode
815 * @dibh: The buffer_head containing the on-disk inode
816 * @pos: The file position
817 * @len: The length of the write
818 * @copied: How much was actually copied by the VFS
819 * @page: The page
820 *
821 * This copies the data from the page into the inode block after
822 * the inode data structure itself.
823 *
824 * Returns: errno
825 */
826static int gfs2_stuffed_write_end(struct inode *inode, struct buffer_head *dibh,
827 loff_t pos, unsigned len, unsigned copied,
828 struct page *page)
829{
830 struct gfs2_inode *ip = GFS2_I(inode);
831 struct gfs2_sbd *sdp = GFS2_SB(inode);
832 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
833 u64 to = pos + copied;
834 void *kaddr;
835 unsigned char *buf = dibh->b_data + sizeof(struct gfs2_dinode);
836
837 BUG_ON(pos + len > gfs2_max_stuffed_size(ip));
838
839 kaddr = kmap_atomic(page);
840 memcpy(buf + pos, kaddr + pos, copied);
841 flush_dcache_page(page);
842 kunmap_atomic(kaddr);
843
844 WARN_ON(!PageUptodate(page));
845 unlock_page(page);
846 put_page(page);
847
848 if (copied) {
849 if (inode->i_size < to)
850 i_size_write(inode, to);
851 mark_inode_dirty(inode);
852 }
853
854 if (inode == sdp->sd_rindex) {
855 adjust_fs_space(inode);
856 sdp->sd_rindex_uptodate = 0;
857 }
858
859 brelse(dibh);
860 gfs2_trans_end(sdp);
861 if (inode == sdp->sd_rindex) {
862 gfs2_glock_dq(&m_ip->i_gh);
863 gfs2_holder_uninit(&m_ip->i_gh);
864 }
865 gfs2_glock_dq(&ip->i_gh);
866 gfs2_holder_uninit(&ip->i_gh);
867 return copied;
868}
869
870/**
871 * gfs2_write_end
872 * @file: The file to write to
873 * @mapping: The address space to write to
874 * @pos: The file position
875 * @len: The length of the data
876 * @copied: How much was actually copied by the VFS
877 * @page: The page that has been written
878 * @fsdata: The fsdata (unused in GFS2)
879 *
880 * The main write_end function for GFS2. We have a separate one for
881 * stuffed files as they are slightly different, otherwise we just
882 * put our locking around the VFS provided functions.
883 *
884 * Returns: errno
885 */
886
887static int gfs2_write_end(struct file *file, struct address_space *mapping,
888 loff_t pos, unsigned len, unsigned copied,
889 struct page *page, void *fsdata)
890{
891 struct inode *inode = page->mapping->host;
892 struct gfs2_inode *ip = GFS2_I(inode);
893 struct gfs2_sbd *sdp = GFS2_SB(inode);
894 struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode);
895 struct buffer_head *dibh;
896 int ret;
897 struct gfs2_trans *tr = current->journal_info;
898 BUG_ON(!tr);
899
900 BUG_ON(gfs2_glock_is_locked_by_me(ip->i_gl) == NULL);
901
902 ret = gfs2_meta_inode_buffer(ip, &dibh);
903 if (unlikely(ret)) {
904 unlock_page(page);
905 put_page(page);
906 goto failed;
907 }
908
909 if (gfs2_is_stuffed(ip))
910 return gfs2_stuffed_write_end(inode, dibh, pos, len, copied, page);
911
912 if (!gfs2_is_writeback(ip))
913 gfs2_page_add_databufs(ip, page, pos & ~PAGE_MASK, len);
914
915 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
916 if (tr->tr_num_buf_new)
917 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
918 else
919 gfs2_trans_add_meta(ip->i_gl, dibh);
920
921
922 if (inode == sdp->sd_rindex) {
923 adjust_fs_space(inode);
924 sdp->sd_rindex_uptodate = 0;
925 }
926
927 brelse(dibh);
928failed:
929 gfs2_trans_end(sdp);
930 gfs2_inplace_release(ip);
931 if (ip->i_qadata && ip->i_qadata->qa_qd_num)
932 gfs2_quota_unlock(ip);
933 if (inode == sdp->sd_rindex) {
934 gfs2_glock_dq(&m_ip->i_gh);
935 gfs2_holder_uninit(&m_ip->i_gh);
936 }
937 gfs2_glock_dq(&ip->i_gh);
938 gfs2_holder_uninit(&ip->i_gh);
939 return ret;
940}
941
942/**
943 * jdata_set_page_dirty - Page dirtying function
944 * @page: The page to dirty
945 *
946 * Returns: 1 if it dirtyed the page, or 0 otherwise
947 */
948
949static int jdata_set_page_dirty(struct page *page)
950{
951 SetPageChecked(page);
952 return __set_page_dirty_buffers(page);
953}
954
955/**
956 * gfs2_bmap - Block map function
957 * @mapping: Address space info
958 * @lblock: The block to map
959 *
960 * Returns: The disk address for the block or 0 on hole or error
961 */
962
963static sector_t gfs2_bmap(struct address_space *mapping, sector_t lblock)
964{
965 struct gfs2_inode *ip = GFS2_I(mapping->host);
966 struct gfs2_holder i_gh;
967 sector_t dblock = 0;
968 int error;
969
970 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
971 if (error)
972 return 0;
973
974 if (!gfs2_is_stuffed(ip))
975 dblock = generic_block_bmap(mapping, lblock, gfs2_block_map);
976
977 gfs2_glock_dq_uninit(&i_gh);
978
979 return dblock;
980}
981
982static void gfs2_discard(struct gfs2_sbd *sdp, struct buffer_head *bh)
983{
984 struct gfs2_bufdata *bd;
985
986 lock_buffer(bh);
987 gfs2_log_lock(sdp);
988 clear_buffer_dirty(bh);
989 bd = bh->b_private;
990 if (bd) {
991 if (!list_empty(&bd->bd_list) && !buffer_pinned(bh))
992 list_del_init(&bd->bd_list);
993 else
994 gfs2_remove_from_journal(bh, REMOVE_JDATA);
995 }
996 bh->b_bdev = NULL;
997 clear_buffer_mapped(bh);
998 clear_buffer_req(bh);
999 clear_buffer_new(bh);
1000 gfs2_log_unlock(sdp);
1001 unlock_buffer(bh);
1002}
1003
1004static void gfs2_invalidatepage(struct page *page, unsigned int offset,
1005 unsigned int length)
1006{
1007 struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
1008 unsigned int stop = offset + length;
1009 int partial_page = (offset || length < PAGE_SIZE);
1010 struct buffer_head *bh, *head;
1011 unsigned long pos = 0;
1012
1013 BUG_ON(!PageLocked(page));
1014 if (!partial_page)
1015 ClearPageChecked(page);
1016 if (!page_has_buffers(page))
1017 goto out;
1018
1019 bh = head = page_buffers(page);
1020 do {
1021 if (pos + bh->b_size > stop)
1022 return;
1023
1024 if (offset <= pos)
1025 gfs2_discard(sdp, bh);
1026 pos += bh->b_size;
1027 bh = bh->b_this_page;
1028 } while (bh != head);
1029out:
1030 if (!partial_page)
1031 try_to_release_page(page, 0);
1032}
1033
1034/**
1035 * gfs2_ok_for_dio - check that dio is valid on this file
1036 * @ip: The inode
1037 * @offset: The offset at which we are reading or writing
1038 *
1039 * Returns: 0 (to ignore the i/o request and thus fall back to buffered i/o)
1040 * 1 (to accept the i/o request)
1041 */
1042static int gfs2_ok_for_dio(struct gfs2_inode *ip, loff_t offset)
1043{
1044 /*
1045 * Should we return an error here? I can't see that O_DIRECT for
1046 * a stuffed file makes any sense. For now we'll silently fall
1047 * back to buffered I/O
1048 */
1049 if (gfs2_is_stuffed(ip))
1050 return 0;
1051
1052 if (offset >= i_size_read(&ip->i_inode))
1053 return 0;
1054 return 1;
1055}
1056
1057
1058
1059static ssize_t gfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
1060{
1061 struct file *file = iocb->ki_filp;
1062 struct inode *inode = file->f_mapping->host;
1063 struct address_space *mapping = inode->i_mapping;
1064 struct gfs2_inode *ip = GFS2_I(inode);
1065 loff_t offset = iocb->ki_pos;
1066 struct gfs2_holder gh;
1067 int rv;
1068
1069 /*
1070 * Deferred lock, even if its a write, since we do no allocation
1071 * on this path. All we need change is atime, and this lock mode
1072 * ensures that other nodes have flushed their buffered read caches
1073 * (i.e. their page cache entries for this inode). We do not,
1074 * unfortunately have the option of only flushing a range like
1075 * the VFS does.
1076 */
1077 gfs2_holder_init(ip->i_gl, LM_ST_DEFERRED, 0, &gh);
1078 rv = gfs2_glock_nq(&gh);
1079 if (rv)
1080 goto out_uninit;
1081 rv = gfs2_ok_for_dio(ip, offset);
1082 if (rv != 1)
1083 goto out; /* dio not valid, fall back to buffered i/o */
1084
1085 /*
1086 * Now since we are holding a deferred (CW) lock at this point, you
1087 * might be wondering why this is ever needed. There is a case however
1088 * where we've granted a deferred local lock against a cached exclusive
1089 * glock. That is ok provided all granted local locks are deferred, but
1090 * it also means that it is possible to encounter pages which are
1091 * cached and possibly also mapped. So here we check for that and sort
1092 * them out ahead of the dio. The glock state machine will take care of
1093 * everything else.
1094 *
1095 * If in fact the cached glock state (gl->gl_state) is deferred (CW) in
1096 * the first place, mapping->nr_pages will always be zero.
1097 */
1098 if (mapping->nrpages) {
1099 loff_t lstart = offset & ~(PAGE_SIZE - 1);
1100 loff_t len = iov_iter_count(iter);
1101 loff_t end = PAGE_ALIGN(offset + len) - 1;
1102
1103 rv = 0;
1104 if (len == 0)
1105 goto out;
1106 if (test_and_clear_bit(GIF_SW_PAGED, &ip->i_flags))
1107 unmap_shared_mapping_range(ip->i_inode.i_mapping, offset, len);
1108 rv = filemap_write_and_wait_range(mapping, lstart, end);
1109 if (rv)
1110 goto out;
1111 if (iov_iter_rw(iter) == WRITE)
1112 truncate_inode_pages_range(mapping, lstart, end);
1113 }
1114
1115 rv = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter,
1116 gfs2_get_block_direct, NULL, NULL, 0);
1117out:
1118 gfs2_glock_dq(&gh);
1119out_uninit:
1120 gfs2_holder_uninit(&gh);
1121 return rv;
1122}
1123
1124/**
1125 * gfs2_releasepage - free the metadata associated with a page
1126 * @page: the page that's being released
1127 * @gfp_mask: passed from Linux VFS, ignored by us
1128 *
1129 * Call try_to_free_buffers() if the buffers in this page can be
1130 * released.
1131 *
1132 * Returns: 0
1133 */
1134
1135int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
1136{
1137 struct address_space *mapping = page->mapping;
1138 struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
1139 struct buffer_head *bh, *head;
1140 struct gfs2_bufdata *bd;
1141
1142 if (!page_has_buffers(page))
1143 return 0;
1144
1145 /*
1146 * From xfs_vm_releasepage: mm accommodates an old ext3 case where
1147 * clean pages might not have had the dirty bit cleared. Thus, it can
1148 * send actual dirty pages to ->releasepage() via shrink_active_list().
1149 *
1150 * As a workaround, we skip pages that contain dirty buffers below.
1151 * Once ->releasepage isn't called on dirty pages anymore, we can warn
1152 * on dirty buffers like we used to here again.
1153 */
1154
1155 gfs2_log_lock(sdp);
1156 spin_lock(&sdp->sd_ail_lock);
1157 head = bh = page_buffers(page);
1158 do {
1159 if (atomic_read(&bh->b_count))
1160 goto cannot_release;
1161 bd = bh->b_private;
1162 if (bd && bd->bd_tr)
1163 goto cannot_release;
1164 if (buffer_dirty(bh) || WARN_ON(buffer_pinned(bh)))
1165 goto cannot_release;
1166 bh = bh->b_this_page;
1167 } while(bh != head);
1168 spin_unlock(&sdp->sd_ail_lock);
1169
1170 head = bh = page_buffers(page);
1171 do {
1172 bd = bh->b_private;
1173 if (bd) {
1174 gfs2_assert_warn(sdp, bd->bd_bh == bh);
1175 if (!list_empty(&bd->bd_list))
1176 list_del_init(&bd->bd_list);
1177 bd->bd_bh = NULL;
1178 bh->b_private = NULL;
1179 kmem_cache_free(gfs2_bufdata_cachep, bd);
1180 }
1181
1182 bh = bh->b_this_page;
1183 } while (bh != head);
1184 gfs2_log_unlock(sdp);
1185
1186 return try_to_free_buffers(page);
1187
1188cannot_release:
1189 spin_unlock(&sdp->sd_ail_lock);
1190 gfs2_log_unlock(sdp);
1191 return 0;
1192}
1193
1194static const struct address_space_operations gfs2_writeback_aops = {
1195 .writepage = gfs2_writepage,
1196 .writepages = gfs2_writepages,
1197 .readpage = gfs2_readpage,
1198 .readpages = gfs2_readpages,
1199 .write_begin = gfs2_write_begin,
1200 .write_end = gfs2_write_end,
1201 .bmap = gfs2_bmap,
1202 .invalidatepage = gfs2_invalidatepage,
1203 .releasepage = gfs2_releasepage,
1204 .direct_IO = gfs2_direct_IO,
1205 .migratepage = buffer_migrate_page,
1206 .is_partially_uptodate = block_is_partially_uptodate,
1207 .error_remove_page = generic_error_remove_page,
1208};
1209
1210static const struct address_space_operations gfs2_ordered_aops = {
1211 .writepage = gfs2_writepage,
1212 .writepages = gfs2_writepages,
1213 .readpage = gfs2_readpage,
1214 .readpages = gfs2_readpages,
1215 .write_begin = gfs2_write_begin,
1216 .write_end = gfs2_write_end,
1217 .set_page_dirty = __set_page_dirty_buffers,
1218 .bmap = gfs2_bmap,
1219 .invalidatepage = gfs2_invalidatepage,
1220 .releasepage = gfs2_releasepage,
1221 .direct_IO = gfs2_direct_IO,
1222 .migratepage = buffer_migrate_page,
1223 .is_partially_uptodate = block_is_partially_uptodate,
1224 .error_remove_page = generic_error_remove_page,
1225};
1226
1227static const struct address_space_operations gfs2_jdata_aops = {
1228 .writepage = gfs2_jdata_writepage,
1229 .writepages = gfs2_jdata_writepages,
1230 .readpage = gfs2_readpage,
1231 .readpages = gfs2_readpages,
1232 .write_begin = gfs2_write_begin,
1233 .write_end = gfs2_write_end,
1234 .set_page_dirty = jdata_set_page_dirty,
1235 .bmap = gfs2_bmap,
1236 .invalidatepage = gfs2_invalidatepage,
1237 .releasepage = gfs2_releasepage,
1238 .is_partially_uptodate = block_is_partially_uptodate,
1239 .error_remove_page = generic_error_remove_page,
1240};
1241
1242void gfs2_set_aops(struct inode *inode)
1243{
1244 struct gfs2_inode *ip = GFS2_I(inode);
1245
1246 if (gfs2_is_writeback(ip))
1247 inode->i_mapping->a_ops = &gfs2_writeback_aops;
1248 else if (gfs2_is_ordered(ip))
1249 inode->i_mapping->a_ops = &gfs2_ordered_aops;
1250 else if (gfs2_is_jdata(ip))
1251 inode->i_mapping->a_ops = &gfs2_jdata_aops;
1252 else
1253 BUG();
1254}
1255