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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * page.c - buffer/page management specific to NILFS
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Ryusuke Konishi and Seiji Kihara.
8 */
9
10#include <linux/pagemap.h>
11#include <linux/writeback.h>
12#include <linux/swap.h>
13#include <linux/bitops.h>
14#include <linux/page-flags.h>
15#include <linux/list.h>
16#include <linux/highmem.h>
17#include <linux/pagevec.h>
18#include <linux/gfp.h>
19#include "nilfs.h"
20#include "page.h"
21#include "mdt.h"
22
23
24#define NILFS_BUFFER_INHERENT_BITS \
25 (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
26 BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
27
28static struct buffer_head *
29__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
30 int blkbits, unsigned long b_state)
31
32{
33 unsigned long first_block;
34 struct buffer_head *bh;
35
36 if (!page_has_buffers(page))
37 create_empty_buffers(page, 1 << blkbits, b_state);
38
39 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
40 bh = nilfs_page_get_nth_block(page, block - first_block);
41
42 touch_buffer(bh);
43 wait_on_buffer(bh);
44 return bh;
45}
46
47struct buffer_head *nilfs_grab_buffer(struct inode *inode,
48 struct address_space *mapping,
49 unsigned long blkoff,
50 unsigned long b_state)
51{
52 int blkbits = inode->i_blkbits;
53 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
54 struct page *page;
55 struct buffer_head *bh;
56
57 page = grab_cache_page(mapping, index);
58 if (unlikely(!page))
59 return NULL;
60
61 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
62 if (unlikely(!bh)) {
63 unlock_page(page);
64 put_page(page);
65 return NULL;
66 }
67 return bh;
68}
69
70/**
71 * nilfs_forget_buffer - discard dirty state
72 * @inode: owner inode of the buffer
73 * @bh: buffer head of the buffer to be discarded
74 */
75void nilfs_forget_buffer(struct buffer_head *bh)
76{
77 struct page *page = bh->b_page;
78 const unsigned long clear_bits =
79 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
80 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
81 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
82
83 lock_buffer(bh);
84 set_mask_bits(&bh->b_state, clear_bits, 0);
85 if (nilfs_page_buffers_clean(page))
86 __nilfs_clear_page_dirty(page);
87
88 bh->b_blocknr = -1;
89 ClearPageUptodate(page);
90 ClearPageMappedToDisk(page);
91 unlock_buffer(bh);
92 brelse(bh);
93}
94
95/**
96 * nilfs_copy_buffer -- copy buffer data and flags
97 * @dbh: destination buffer
98 * @sbh: source buffer
99 */
100void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
101{
102 void *kaddr0, *kaddr1;
103 unsigned long bits;
104 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
105 struct buffer_head *bh;
106
107 kaddr0 = kmap_atomic(spage);
108 kaddr1 = kmap_atomic(dpage);
109 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
110 kunmap_atomic(kaddr1);
111 kunmap_atomic(kaddr0);
112
113 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
114 dbh->b_blocknr = sbh->b_blocknr;
115 dbh->b_bdev = sbh->b_bdev;
116
117 bh = dbh;
118 bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
119 while ((bh = bh->b_this_page) != dbh) {
120 lock_buffer(bh);
121 bits &= bh->b_state;
122 unlock_buffer(bh);
123 }
124 if (bits & BIT(BH_Uptodate))
125 SetPageUptodate(dpage);
126 else
127 ClearPageUptodate(dpage);
128 if (bits & BIT(BH_Mapped))
129 SetPageMappedToDisk(dpage);
130 else
131 ClearPageMappedToDisk(dpage);
132}
133
134/**
135 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
136 * @page: page to be checked
137 *
138 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
139 * Otherwise, it returns non-zero value.
140 */
141int nilfs_page_buffers_clean(struct page *page)
142{
143 struct buffer_head *bh, *head;
144
145 bh = head = page_buffers(page);
146 do {
147 if (buffer_dirty(bh))
148 return 0;
149 bh = bh->b_this_page;
150 } while (bh != head);
151 return 1;
152}
153
154void nilfs_page_bug(struct page *page)
155{
156 struct address_space *m;
157 unsigned long ino;
158
159 if (unlikely(!page)) {
160 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
161 return;
162 }
163
164 m = page->mapping;
165 ino = m ? m->host->i_ino : 0;
166
167 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
168 "mapping=%p ino=%lu\n",
169 page, page_ref_count(page),
170 (unsigned long long)page->index, page->flags, m, ino);
171
172 if (page_has_buffers(page)) {
173 struct buffer_head *bh, *head;
174 int i = 0;
175
176 bh = head = page_buffers(page);
177 do {
178 printk(KERN_CRIT
179 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
180 i++, bh, atomic_read(&bh->b_count),
181 (unsigned long long)bh->b_blocknr, bh->b_state);
182 bh = bh->b_this_page;
183 } while (bh != head);
184 }
185}
186
187/**
188 * nilfs_copy_page -- copy the page with buffers
189 * @dst: destination page
190 * @src: source page
191 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
192 *
193 * This function is for both data pages and btnode pages. The dirty flag
194 * should be treated by caller. The page must not be under i/o.
195 * Both src and dst page must be locked
196 */
197static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
198{
199 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
200 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
201
202 BUG_ON(PageWriteback(dst));
203
204 sbh = sbufs = page_buffers(src);
205 if (!page_has_buffers(dst))
206 create_empty_buffers(dst, sbh->b_size, 0);
207
208 if (copy_dirty)
209 mask |= BIT(BH_Dirty);
210
211 dbh = dbufs = page_buffers(dst);
212 do {
213 lock_buffer(sbh);
214 lock_buffer(dbh);
215 dbh->b_state = sbh->b_state & mask;
216 dbh->b_blocknr = sbh->b_blocknr;
217 dbh->b_bdev = sbh->b_bdev;
218 sbh = sbh->b_this_page;
219 dbh = dbh->b_this_page;
220 } while (dbh != dbufs);
221
222 copy_highpage(dst, src);
223
224 if (PageUptodate(src) && !PageUptodate(dst))
225 SetPageUptodate(dst);
226 else if (!PageUptodate(src) && PageUptodate(dst))
227 ClearPageUptodate(dst);
228 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
229 SetPageMappedToDisk(dst);
230 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
231 ClearPageMappedToDisk(dst);
232
233 do {
234 unlock_buffer(sbh);
235 unlock_buffer(dbh);
236 sbh = sbh->b_this_page;
237 dbh = dbh->b_this_page;
238 } while (dbh != dbufs);
239}
240
241int nilfs_copy_dirty_pages(struct address_space *dmap,
242 struct address_space *smap)
243{
244 struct pagevec pvec;
245 unsigned int i;
246 pgoff_t index = 0;
247 int err = 0;
248
249 pagevec_init(&pvec);
250repeat:
251 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
252 return 0;
253
254 for (i = 0; i < pagevec_count(&pvec); i++) {
255 struct page *page = pvec.pages[i], *dpage;
256
257 lock_page(page);
258 if (unlikely(!PageDirty(page)))
259 NILFS_PAGE_BUG(page, "inconsistent dirty state");
260
261 dpage = grab_cache_page(dmap, page->index);
262 if (unlikely(!dpage)) {
263 /* No empty page is added to the page cache */
264 err = -ENOMEM;
265 unlock_page(page);
266 break;
267 }
268 if (unlikely(!page_has_buffers(page)))
269 NILFS_PAGE_BUG(page,
270 "found empty page in dat page cache");
271
272 nilfs_copy_page(dpage, page, 1);
273 __set_page_dirty_nobuffers(dpage);
274
275 unlock_page(dpage);
276 put_page(dpage);
277 unlock_page(page);
278 }
279 pagevec_release(&pvec);
280 cond_resched();
281
282 if (likely(!err))
283 goto repeat;
284 return err;
285}
286
287/**
288 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
289 * @dmap: destination page cache
290 * @smap: source page cache
291 *
292 * No pages must be added to the cache during this process.
293 * This must be ensured by the caller.
294 */
295void nilfs_copy_back_pages(struct address_space *dmap,
296 struct address_space *smap)
297{
298 struct pagevec pvec;
299 unsigned int i, n;
300 pgoff_t index = 0;
301
302 pagevec_init(&pvec);
303repeat:
304 n = pagevec_lookup(&pvec, smap, &index);
305 if (!n)
306 return;
307
308 for (i = 0; i < pagevec_count(&pvec); i++) {
309 struct page *page = pvec.pages[i], *dpage;
310 pgoff_t offset = page->index;
311
312 lock_page(page);
313 dpage = find_lock_page(dmap, offset);
314 if (dpage) {
315 /* overwrite existing page in the destination cache */
316 WARN_ON(PageDirty(dpage));
317 nilfs_copy_page(dpage, page, 0);
318 unlock_page(dpage);
319 put_page(dpage);
320 /* Do we not need to remove page from smap here? */
321 } else {
322 struct page *p;
323
324 /* move the page to the destination cache */
325 xa_lock_irq(&smap->i_pages);
326 p = __xa_erase(&smap->i_pages, offset);
327 WARN_ON(page != p);
328 smap->nrpages--;
329 xa_unlock_irq(&smap->i_pages);
330
331 xa_lock_irq(&dmap->i_pages);
332 p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
333 if (unlikely(p)) {
334 /* Probably -ENOMEM */
335 page->mapping = NULL;
336 put_page(page);
337 } else {
338 page->mapping = dmap;
339 dmap->nrpages++;
340 if (PageDirty(page))
341 __xa_set_mark(&dmap->i_pages, offset,
342 PAGECACHE_TAG_DIRTY);
343 }
344 xa_unlock_irq(&dmap->i_pages);
345 }
346 unlock_page(page);
347 }
348 pagevec_release(&pvec);
349 cond_resched();
350
351 goto repeat;
352}
353
354/**
355 * nilfs_clear_dirty_pages - discard dirty pages in address space
356 * @mapping: address space with dirty pages for discarding
357 * @silent: suppress [true] or print [false] warning messages
358 */
359void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
360{
361 struct pagevec pvec;
362 unsigned int i;
363 pgoff_t index = 0;
364
365 pagevec_init(&pvec);
366
367 while (pagevec_lookup_tag(&pvec, mapping, &index,
368 PAGECACHE_TAG_DIRTY)) {
369 for (i = 0; i < pagevec_count(&pvec); i++) {
370 struct page *page = pvec.pages[i];
371
372 lock_page(page);
373 nilfs_clear_dirty_page(page, silent);
374 unlock_page(page);
375 }
376 pagevec_release(&pvec);
377 cond_resched();
378 }
379}
380
381/**
382 * nilfs_clear_dirty_page - discard dirty page
383 * @page: dirty page that will be discarded
384 * @silent: suppress [true] or print [false] warning messages
385 */
386void nilfs_clear_dirty_page(struct page *page, bool silent)
387{
388 struct inode *inode = page->mapping->host;
389 struct super_block *sb = inode->i_sb;
390
391 BUG_ON(!PageLocked(page));
392
393 if (!silent)
394 nilfs_msg(sb, KERN_WARNING,
395 "discard dirty page: offset=%lld, ino=%lu",
396 page_offset(page), inode->i_ino);
397
398 ClearPageUptodate(page);
399 ClearPageMappedToDisk(page);
400
401 if (page_has_buffers(page)) {
402 struct buffer_head *bh, *head;
403 const unsigned long clear_bits =
404 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
405 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
406 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
407
408 bh = head = page_buffers(page);
409 do {
410 lock_buffer(bh);
411 if (!silent)
412 nilfs_msg(sb, KERN_WARNING,
413 "discard dirty block: blocknr=%llu, size=%zu",
414 (u64)bh->b_blocknr, bh->b_size);
415
416 set_mask_bits(&bh->b_state, clear_bits, 0);
417 unlock_buffer(bh);
418 } while (bh = bh->b_this_page, bh != head);
419 }
420
421 __nilfs_clear_page_dirty(page);
422}
423
424unsigned int nilfs_page_count_clean_buffers(struct page *page,
425 unsigned int from, unsigned int to)
426{
427 unsigned int block_start, block_end;
428 struct buffer_head *bh, *head;
429 unsigned int nc = 0;
430
431 for (bh = head = page_buffers(page), block_start = 0;
432 bh != head || !block_start;
433 block_start = block_end, bh = bh->b_this_page) {
434 block_end = block_start + bh->b_size;
435 if (block_end > from && block_start < to && !buffer_dirty(bh))
436 nc++;
437 }
438 return nc;
439}
440
441void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
442{
443 mapping->host = inode;
444 mapping->flags = 0;
445 mapping_set_gfp_mask(mapping, GFP_NOFS);
446 mapping->private_data = NULL;
447 mapping->a_ops = &empty_aops;
448}
449
450/*
451 * NILFS2 needs clear_page_dirty() in the following two cases:
452 *
453 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
454 * page dirty flags when it copies back pages from the shadow cache
455 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
456 * (dat->{i_mapping,i_btnode_cache}).
457 *
458 * 2) Some B-tree operations like insertion or deletion may dispose buffers
459 * in dirty state, and this needs to cancel the dirty state of their pages.
460 */
461int __nilfs_clear_page_dirty(struct page *page)
462{
463 struct address_space *mapping = page->mapping;
464
465 if (mapping) {
466 xa_lock_irq(&mapping->i_pages);
467 if (test_bit(PG_dirty, &page->flags)) {
468 __xa_clear_mark(&mapping->i_pages, page_index(page),
469 PAGECACHE_TAG_DIRTY);
470 xa_unlock_irq(&mapping->i_pages);
471 return clear_page_dirty_for_io(page);
472 }
473 xa_unlock_irq(&mapping->i_pages);
474 return 0;
475 }
476 return TestClearPageDirty(page);
477}
478
479/**
480 * nilfs_find_uncommitted_extent - find extent of uncommitted data
481 * @inode: inode
482 * @start_blk: start block offset (in)
483 * @blkoff: start offset of the found extent (out)
484 *
485 * This function searches an extent of buffers marked "delayed" which
486 * starts from a block offset equal to or larger than @start_blk. If
487 * such an extent was found, this will store the start offset in
488 * @blkoff and return its length in blocks. Otherwise, zero is
489 * returned.
490 */
491unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
492 sector_t start_blk,
493 sector_t *blkoff)
494{
495 unsigned int i;
496 pgoff_t index;
497 unsigned int nblocks_in_page;
498 unsigned long length = 0;
499 sector_t b;
500 struct pagevec pvec;
501 struct page *page;
502
503 if (inode->i_mapping->nrpages == 0)
504 return 0;
505
506 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
507 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
508
509 pagevec_init(&pvec);
510
511repeat:
512 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
513 pvec.pages);
514 if (pvec.nr == 0)
515 return length;
516
517 if (length > 0 && pvec.pages[0]->index > index)
518 goto out;
519
520 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
521 i = 0;
522 do {
523 page = pvec.pages[i];
524
525 lock_page(page);
526 if (page_has_buffers(page)) {
527 struct buffer_head *bh, *head;
528
529 bh = head = page_buffers(page);
530 do {
531 if (b < start_blk)
532 continue;
533 if (buffer_delay(bh)) {
534 if (length == 0)
535 *blkoff = b;
536 length++;
537 } else if (length > 0) {
538 goto out_locked;
539 }
540 } while (++b, bh = bh->b_this_page, bh != head);
541 } else {
542 if (length > 0)
543 goto out_locked;
544
545 b += nblocks_in_page;
546 }
547 unlock_page(page);
548
549 } while (++i < pagevec_count(&pvec));
550
551 index = page->index + 1;
552 pagevec_release(&pvec);
553 cond_resched();
554 goto repeat;
555
556out_locked:
557 unlock_page(page);
558out:
559 pagevec_release(&pvec);
560 return length;
561}
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * page.c - buffer/page management specific to NILFS
4 *
5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
6 *
7 * Written by Ryusuke Konishi and Seiji Kihara.
8 */
9
10#include <linux/pagemap.h>
11#include <linux/writeback.h>
12#include <linux/swap.h>
13#include <linux/bitops.h>
14#include <linux/page-flags.h>
15#include <linux/list.h>
16#include <linux/highmem.h>
17#include <linux/pagevec.h>
18#include <linux/gfp.h>
19#include "nilfs.h"
20#include "page.h"
21#include "mdt.h"
22
23
24#define NILFS_BUFFER_INHERENT_BITS \
25 (BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
26 BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
27
28static struct buffer_head *
29__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
30 int blkbits, unsigned long b_state)
31
32{
33 unsigned long first_block;
34 struct buffer_head *bh;
35
36 if (!page_has_buffers(page))
37 create_empty_buffers(page, 1 << blkbits, b_state);
38
39 first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
40 bh = nilfs_page_get_nth_block(page, block - first_block);
41
42 touch_buffer(bh);
43 wait_on_buffer(bh);
44 return bh;
45}
46
47struct buffer_head *nilfs_grab_buffer(struct inode *inode,
48 struct address_space *mapping,
49 unsigned long blkoff,
50 unsigned long b_state)
51{
52 int blkbits = inode->i_blkbits;
53 pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
54 struct page *page;
55 struct buffer_head *bh;
56
57 page = grab_cache_page(mapping, index);
58 if (unlikely(!page))
59 return NULL;
60
61 bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
62 if (unlikely(!bh)) {
63 unlock_page(page);
64 put_page(page);
65 return NULL;
66 }
67 return bh;
68}
69
70/**
71 * nilfs_forget_buffer - discard dirty state
72 * @inode: owner inode of the buffer
73 * @bh: buffer head of the buffer to be discarded
74 */
75void nilfs_forget_buffer(struct buffer_head *bh)
76{
77 struct page *page = bh->b_page;
78 const unsigned long clear_bits =
79 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
80 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
81 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
82
83 lock_buffer(bh);
84 set_mask_bits(&bh->b_state, clear_bits, 0);
85 if (nilfs_page_buffers_clean(page))
86 __nilfs_clear_page_dirty(page);
87
88 bh->b_blocknr = -1;
89 ClearPageUptodate(page);
90 ClearPageMappedToDisk(page);
91 unlock_buffer(bh);
92 brelse(bh);
93}
94
95/**
96 * nilfs_copy_buffer -- copy buffer data and flags
97 * @dbh: destination buffer
98 * @sbh: source buffer
99 */
100void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
101{
102 void *kaddr0, *kaddr1;
103 unsigned long bits;
104 struct page *spage = sbh->b_page, *dpage = dbh->b_page;
105 struct buffer_head *bh;
106
107 kaddr0 = kmap_atomic(spage);
108 kaddr1 = kmap_atomic(dpage);
109 memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
110 kunmap_atomic(kaddr1);
111 kunmap_atomic(kaddr0);
112
113 dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
114 dbh->b_blocknr = sbh->b_blocknr;
115 dbh->b_bdev = sbh->b_bdev;
116
117 bh = dbh;
118 bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
119 while ((bh = bh->b_this_page) != dbh) {
120 lock_buffer(bh);
121 bits &= bh->b_state;
122 unlock_buffer(bh);
123 }
124 if (bits & BIT(BH_Uptodate))
125 SetPageUptodate(dpage);
126 else
127 ClearPageUptodate(dpage);
128 if (bits & BIT(BH_Mapped))
129 SetPageMappedToDisk(dpage);
130 else
131 ClearPageMappedToDisk(dpage);
132}
133
134/**
135 * nilfs_page_buffers_clean - check if a page has dirty buffers or not.
136 * @page: page to be checked
137 *
138 * nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
139 * Otherwise, it returns non-zero value.
140 */
141int nilfs_page_buffers_clean(struct page *page)
142{
143 struct buffer_head *bh, *head;
144
145 bh = head = page_buffers(page);
146 do {
147 if (buffer_dirty(bh))
148 return 0;
149 bh = bh->b_this_page;
150 } while (bh != head);
151 return 1;
152}
153
154void nilfs_page_bug(struct page *page)
155{
156 struct address_space *m;
157 unsigned long ino;
158
159 if (unlikely(!page)) {
160 printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
161 return;
162 }
163
164 m = page->mapping;
165 ino = m ? m->host->i_ino : 0;
166
167 printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
168 "mapping=%p ino=%lu\n",
169 page, page_ref_count(page),
170 (unsigned long long)page->index, page->flags, m, ino);
171
172 if (page_has_buffers(page)) {
173 struct buffer_head *bh, *head;
174 int i = 0;
175
176 bh = head = page_buffers(page);
177 do {
178 printk(KERN_CRIT
179 " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
180 i++, bh, atomic_read(&bh->b_count),
181 (unsigned long long)bh->b_blocknr, bh->b_state);
182 bh = bh->b_this_page;
183 } while (bh != head);
184 }
185}
186
187/**
188 * nilfs_copy_page -- copy the page with buffers
189 * @dst: destination page
190 * @src: source page
191 * @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
192 *
193 * This function is for both data pages and btnode pages. The dirty flag
194 * should be treated by caller. The page must not be under i/o.
195 * Both src and dst page must be locked
196 */
197static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
198{
199 struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
200 unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
201
202 BUG_ON(PageWriteback(dst));
203
204 sbh = sbufs = page_buffers(src);
205 if (!page_has_buffers(dst))
206 create_empty_buffers(dst, sbh->b_size, 0);
207
208 if (copy_dirty)
209 mask |= BIT(BH_Dirty);
210
211 dbh = dbufs = page_buffers(dst);
212 do {
213 lock_buffer(sbh);
214 lock_buffer(dbh);
215 dbh->b_state = sbh->b_state & mask;
216 dbh->b_blocknr = sbh->b_blocknr;
217 dbh->b_bdev = sbh->b_bdev;
218 sbh = sbh->b_this_page;
219 dbh = dbh->b_this_page;
220 } while (dbh != dbufs);
221
222 copy_highpage(dst, src);
223
224 if (PageUptodate(src) && !PageUptodate(dst))
225 SetPageUptodate(dst);
226 else if (!PageUptodate(src) && PageUptodate(dst))
227 ClearPageUptodate(dst);
228 if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
229 SetPageMappedToDisk(dst);
230 else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
231 ClearPageMappedToDisk(dst);
232
233 do {
234 unlock_buffer(sbh);
235 unlock_buffer(dbh);
236 sbh = sbh->b_this_page;
237 dbh = dbh->b_this_page;
238 } while (dbh != dbufs);
239}
240
241int nilfs_copy_dirty_pages(struct address_space *dmap,
242 struct address_space *smap)
243{
244 struct pagevec pvec;
245 unsigned int i;
246 pgoff_t index = 0;
247 int err = 0;
248
249 pagevec_init(&pvec);
250repeat:
251 if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
252 return 0;
253
254 for (i = 0; i < pagevec_count(&pvec); i++) {
255 struct page *page = pvec.pages[i], *dpage;
256
257 lock_page(page);
258 if (unlikely(!PageDirty(page)))
259 NILFS_PAGE_BUG(page, "inconsistent dirty state");
260
261 dpage = grab_cache_page(dmap, page->index);
262 if (unlikely(!dpage)) {
263 /* No empty page is added to the page cache */
264 err = -ENOMEM;
265 unlock_page(page);
266 break;
267 }
268 if (unlikely(!page_has_buffers(page)))
269 NILFS_PAGE_BUG(page,
270 "found empty page in dat page cache");
271
272 nilfs_copy_page(dpage, page, 1);
273 __set_page_dirty_nobuffers(dpage);
274
275 unlock_page(dpage);
276 put_page(dpage);
277 unlock_page(page);
278 }
279 pagevec_release(&pvec);
280 cond_resched();
281
282 if (likely(!err))
283 goto repeat;
284 return err;
285}
286
287/**
288 * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
289 * @dmap: destination page cache
290 * @smap: source page cache
291 *
292 * No pages must be added to the cache during this process.
293 * This must be ensured by the caller.
294 */
295void nilfs_copy_back_pages(struct address_space *dmap,
296 struct address_space *smap)
297{
298 struct pagevec pvec;
299 unsigned int i, n;
300 pgoff_t index = 0;
301
302 pagevec_init(&pvec);
303repeat:
304 n = pagevec_lookup(&pvec, smap, &index);
305 if (!n)
306 return;
307
308 for (i = 0; i < pagevec_count(&pvec); i++) {
309 struct page *page = pvec.pages[i], *dpage;
310 pgoff_t offset = page->index;
311
312 lock_page(page);
313 dpage = find_lock_page(dmap, offset);
314 if (dpage) {
315 /* overwrite existing page in the destination cache */
316 WARN_ON(PageDirty(dpage));
317 nilfs_copy_page(dpage, page, 0);
318 unlock_page(dpage);
319 put_page(dpage);
320 /* Do we not need to remove page from smap here? */
321 } else {
322 struct page *p;
323
324 /* move the page to the destination cache */
325 xa_lock_irq(&smap->i_pages);
326 p = __xa_erase(&smap->i_pages, offset);
327 WARN_ON(page != p);
328 smap->nrpages--;
329 xa_unlock_irq(&smap->i_pages);
330
331 xa_lock_irq(&dmap->i_pages);
332 p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
333 if (unlikely(p)) {
334 /* Probably -ENOMEM */
335 page->mapping = NULL;
336 put_page(page);
337 } else {
338 page->mapping = dmap;
339 dmap->nrpages++;
340 if (PageDirty(page))
341 __xa_set_mark(&dmap->i_pages, offset,
342 PAGECACHE_TAG_DIRTY);
343 }
344 xa_unlock_irq(&dmap->i_pages);
345 }
346 unlock_page(page);
347 }
348 pagevec_release(&pvec);
349 cond_resched();
350
351 goto repeat;
352}
353
354/**
355 * nilfs_clear_dirty_pages - discard dirty pages in address space
356 * @mapping: address space with dirty pages for discarding
357 * @silent: suppress [true] or print [false] warning messages
358 */
359void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
360{
361 struct pagevec pvec;
362 unsigned int i;
363 pgoff_t index = 0;
364
365 pagevec_init(&pvec);
366
367 while (pagevec_lookup_tag(&pvec, mapping, &index,
368 PAGECACHE_TAG_DIRTY)) {
369 for (i = 0; i < pagevec_count(&pvec); i++) {
370 struct page *page = pvec.pages[i];
371
372 lock_page(page);
373 nilfs_clear_dirty_page(page, silent);
374 unlock_page(page);
375 }
376 pagevec_release(&pvec);
377 cond_resched();
378 }
379}
380
381/**
382 * nilfs_clear_dirty_page - discard dirty page
383 * @page: dirty page that will be discarded
384 * @silent: suppress [true] or print [false] warning messages
385 */
386void nilfs_clear_dirty_page(struct page *page, bool silent)
387{
388 struct inode *inode = page->mapping->host;
389 struct super_block *sb = inode->i_sb;
390
391 BUG_ON(!PageLocked(page));
392
393 if (!silent)
394 nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu",
395 page_offset(page), inode->i_ino);
396
397 ClearPageUptodate(page);
398 ClearPageMappedToDisk(page);
399
400 if (page_has_buffers(page)) {
401 struct buffer_head *bh, *head;
402 const unsigned long clear_bits =
403 (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
404 BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
405 BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
406
407 bh = head = page_buffers(page);
408 do {
409 lock_buffer(bh);
410 if (!silent)
411 nilfs_warn(sb,
412 "discard dirty block: blocknr=%llu, size=%zu",
413 (u64)bh->b_blocknr, bh->b_size);
414
415 set_mask_bits(&bh->b_state, clear_bits, 0);
416 unlock_buffer(bh);
417 } while (bh = bh->b_this_page, bh != head);
418 }
419
420 __nilfs_clear_page_dirty(page);
421}
422
423unsigned int nilfs_page_count_clean_buffers(struct page *page,
424 unsigned int from, unsigned int to)
425{
426 unsigned int block_start, block_end;
427 struct buffer_head *bh, *head;
428 unsigned int nc = 0;
429
430 for (bh = head = page_buffers(page), block_start = 0;
431 bh != head || !block_start;
432 block_start = block_end, bh = bh->b_this_page) {
433 block_end = block_start + bh->b_size;
434 if (block_end > from && block_start < to && !buffer_dirty(bh))
435 nc++;
436 }
437 return nc;
438}
439
440void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
441{
442 mapping->host = inode;
443 mapping->flags = 0;
444 mapping_set_gfp_mask(mapping, GFP_NOFS);
445 mapping->private_data = NULL;
446 mapping->a_ops = &empty_aops;
447}
448
449/*
450 * NILFS2 needs clear_page_dirty() in the following two cases:
451 *
452 * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
453 * page dirty flags when it copies back pages from the shadow cache
454 * (gcdat->{i_mapping,i_btnode_cache}) to its original cache
455 * (dat->{i_mapping,i_btnode_cache}).
456 *
457 * 2) Some B-tree operations like insertion or deletion may dispose buffers
458 * in dirty state, and this needs to cancel the dirty state of their pages.
459 */
460int __nilfs_clear_page_dirty(struct page *page)
461{
462 struct address_space *mapping = page->mapping;
463
464 if (mapping) {
465 xa_lock_irq(&mapping->i_pages);
466 if (test_bit(PG_dirty, &page->flags)) {
467 __xa_clear_mark(&mapping->i_pages, page_index(page),
468 PAGECACHE_TAG_DIRTY);
469 xa_unlock_irq(&mapping->i_pages);
470 return clear_page_dirty_for_io(page);
471 }
472 xa_unlock_irq(&mapping->i_pages);
473 return 0;
474 }
475 return TestClearPageDirty(page);
476}
477
478/**
479 * nilfs_find_uncommitted_extent - find extent of uncommitted data
480 * @inode: inode
481 * @start_blk: start block offset (in)
482 * @blkoff: start offset of the found extent (out)
483 *
484 * This function searches an extent of buffers marked "delayed" which
485 * starts from a block offset equal to or larger than @start_blk. If
486 * such an extent was found, this will store the start offset in
487 * @blkoff and return its length in blocks. Otherwise, zero is
488 * returned.
489 */
490unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
491 sector_t start_blk,
492 sector_t *blkoff)
493{
494 unsigned int i;
495 pgoff_t index;
496 unsigned int nblocks_in_page;
497 unsigned long length = 0;
498 sector_t b;
499 struct pagevec pvec;
500 struct page *page;
501
502 if (inode->i_mapping->nrpages == 0)
503 return 0;
504
505 index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
506 nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
507
508 pagevec_init(&pvec);
509
510repeat:
511 pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
512 pvec.pages);
513 if (pvec.nr == 0)
514 return length;
515
516 if (length > 0 && pvec.pages[0]->index > index)
517 goto out;
518
519 b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
520 i = 0;
521 do {
522 page = pvec.pages[i];
523
524 lock_page(page);
525 if (page_has_buffers(page)) {
526 struct buffer_head *bh, *head;
527
528 bh = head = page_buffers(page);
529 do {
530 if (b < start_blk)
531 continue;
532 if (buffer_delay(bh)) {
533 if (length == 0)
534 *blkoff = b;
535 length++;
536 } else if (length > 0) {
537 goto out_locked;
538 }
539 } while (++b, bh = bh->b_this_page, bh != head);
540 } else {
541 if (length > 0)
542 goto out_locked;
543
544 b += nblocks_in_page;
545 }
546 unlock_page(page);
547
548 } while (++i < pagevec_count(&pvec));
549
550 index = page->index + 1;
551 pagevec_release(&pvec);
552 cond_resched();
553 goto repeat;
554
555out_locked:
556 unlock_page(page);
557out:
558 pagevec_release(&pvec);
559 return length;
560}