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ae98043f | 1 | // SPDX-License-Identifier: GPL-2.0+ |
0bd49f94 RK |
2 | /* |
3 | * page.c - buffer/page management specific to NILFS | |
4 | * | |
5 | * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. | |
6 | * | |
4b420ab4 | 7 | * Written by Ryusuke Konishi and Seiji Kihara. |
0bd49f94 RK |
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> | |
5a0e3ad6 | 18 | #include <linux/gfp.h> |
0bd49f94 RK |
19 | #include "nilfs.h" |
20 | #include "page.h" | |
21 | #include "mdt.h" | |
22 | ||
23 | ||
4ce5c342 RK |
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)) | |
0bd49f94 RK |
27 | |
28 | static 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 | ||
09cbfeaf | 39 | first_block = (unsigned long)index << (PAGE_SHIFT - blkbits); |
0bd49f94 RK |
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 | ||
0bd49f94 RK |
47 | struct 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; | |
09cbfeaf | 53 | pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits); |
c1c1d709 RK |
54 | struct page *page; |
55 | struct buffer_head *bh; | |
0bd49f94 RK |
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); | |
09cbfeaf | 64 | put_page(page); |
0bd49f94 RK |
65 | return NULL; |
66 | } | |
0bd49f94 RK |
67 | return bh; |
68 | } | |
69 | ||
70 | /** | |
71 | * nilfs_forget_buffer - discard dirty state | |
0bd49f94 RK |
72 | * @bh: buffer head of the buffer to be discarded |
73 | */ | |
74 | void nilfs_forget_buffer(struct buffer_head *bh) | |
75 | { | |
76 | struct page *page = bh->b_page; | |
ead8ecff | 77 | const unsigned long clear_bits = |
4ce5c342 RK |
78 | (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | |
79 | BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | | |
80 | BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); | |
0bd49f94 RK |
81 | |
82 | lock_buffer(bh); | |
ead8ecff | 83 | set_mask_bits(&bh->b_state, clear_bits, 0); |
84338237 | 84 | if (nilfs_page_buffers_clean(page)) |
0bd49f94 RK |
85 | __nilfs_clear_page_dirty(page); |
86 | ||
0bd49f94 RK |
87 | bh->b_blocknr = -1; |
88 | ClearPageUptodate(page); | |
89 | ClearPageMappedToDisk(page); | |
90 | unlock_buffer(bh); | |
91 | brelse(bh); | |
92 | } | |
93 | ||
94 | /** | |
95 | * nilfs_copy_buffer -- copy buffer data and flags | |
96 | * @dbh: destination buffer | |
97 | * @sbh: source buffer | |
98 | */ | |
99 | void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh) | |
100 | { | |
101 | void *kaddr0, *kaddr1; | |
102 | unsigned long bits; | |
103 | struct page *spage = sbh->b_page, *dpage = dbh->b_page; | |
104 | struct buffer_head *bh; | |
105 | ||
7b9c0976 CW |
106 | kaddr0 = kmap_atomic(spage); |
107 | kaddr1 = kmap_atomic(dpage); | |
0bd49f94 | 108 | memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size); |
7b9c0976 CW |
109 | kunmap_atomic(kaddr1); |
110 | kunmap_atomic(kaddr0); | |
0bd49f94 RK |
111 | |
112 | dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS; | |
113 | dbh->b_blocknr = sbh->b_blocknr; | |
114 | dbh->b_bdev = sbh->b_bdev; | |
115 | ||
116 | bh = dbh; | |
4ce5c342 | 117 | bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped)); |
0bd49f94 RK |
118 | while ((bh = bh->b_this_page) != dbh) { |
119 | lock_buffer(bh); | |
120 | bits &= bh->b_state; | |
121 | unlock_buffer(bh); | |
122 | } | |
4ce5c342 | 123 | if (bits & BIT(BH_Uptodate)) |
0bd49f94 RK |
124 | SetPageUptodate(dpage); |
125 | else | |
126 | ClearPageUptodate(dpage); | |
4ce5c342 | 127 | if (bits & BIT(BH_Mapped)) |
0bd49f94 RK |
128 | SetPageMappedToDisk(dpage); |
129 | else | |
130 | ClearPageMappedToDisk(dpage); | |
131 | } | |
132 | ||
133 | /** | |
134 | * nilfs_page_buffers_clean - check if a page has dirty buffers or not. | |
135 | * @page: page to be checked | |
136 | * | |
137 | * nilfs_page_buffers_clean() returns zero if the page has dirty buffers. | |
138 | * Otherwise, it returns non-zero value. | |
139 | */ | |
140 | int nilfs_page_buffers_clean(struct page *page) | |
141 | { | |
142 | struct buffer_head *bh, *head; | |
143 | ||
144 | bh = head = page_buffers(page); | |
145 | do { | |
146 | if (buffer_dirty(bh)) | |
147 | return 0; | |
148 | bh = bh->b_this_page; | |
149 | } while (bh != head); | |
150 | return 1; | |
151 | } | |
152 | ||
153 | void nilfs_page_bug(struct page *page) | |
154 | { | |
155 | struct address_space *m; | |
aa405b1f | 156 | unsigned long ino; |
0bd49f94 RK |
157 | |
158 | if (unlikely(!page)) { | |
159 | printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n"); | |
160 | return; | |
161 | } | |
162 | ||
163 | m = page->mapping; | |
aa405b1f RK |
164 | ino = m ? m->host->i_ino : 0; |
165 | ||
0bd49f94 RK |
166 | printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx " |
167 | "mapping=%p ino=%lu\n", | |
fe896d18 | 168 | page, page_ref_count(page), |
0bd49f94 RK |
169 | (unsigned long long)page->index, page->flags, m, ino); |
170 | ||
171 | if (page_has_buffers(page)) { | |
172 | struct buffer_head *bh, *head; | |
173 | int i = 0; | |
174 | ||
175 | bh = head = page_buffers(page); | |
176 | do { | |
177 | printk(KERN_CRIT | |
178 | " BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n", | |
179 | i++, bh, atomic_read(&bh->b_count), | |
180 | (unsigned long long)bh->b_blocknr, bh->b_state); | |
181 | bh = bh->b_this_page; | |
182 | } while (bh != head); | |
183 | } | |
184 | } | |
185 | ||
0bd49f94 RK |
186 | /** |
187 | * nilfs_copy_page -- copy the page with buffers | |
188 | * @dst: destination page | |
189 | * @src: source page | |
190 | * @copy_dirty: flag whether to copy dirty states on the page's buffer heads. | |
191 | * | |
7a65004b | 192 | * This function is for both data pages and btnode pages. The dirty flag |
0bd49f94 RK |
193 | * should be treated by caller. The page must not be under i/o. |
194 | * Both src and dst page must be locked | |
195 | */ | |
196 | static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty) | |
197 | { | |
198 | struct buffer_head *dbh, *dbufs, *sbh, *sbufs; | |
199 | unsigned long mask = NILFS_BUFFER_INHERENT_BITS; | |
200 | ||
201 | BUG_ON(PageWriteback(dst)); | |
202 | ||
203 | sbh = sbufs = page_buffers(src); | |
204 | if (!page_has_buffers(dst)) | |
205 | create_empty_buffers(dst, sbh->b_size, 0); | |
206 | ||
207 | if (copy_dirty) | |
4ce5c342 | 208 | mask |= BIT(BH_Dirty); |
0bd49f94 RK |
209 | |
210 | dbh = dbufs = page_buffers(dst); | |
211 | do { | |
212 | lock_buffer(sbh); | |
213 | lock_buffer(dbh); | |
214 | dbh->b_state = sbh->b_state & mask; | |
215 | dbh->b_blocknr = sbh->b_blocknr; | |
216 | dbh->b_bdev = sbh->b_bdev; | |
217 | sbh = sbh->b_this_page; | |
218 | dbh = dbh->b_this_page; | |
219 | } while (dbh != dbufs); | |
220 | ||
221 | copy_highpage(dst, src); | |
222 | ||
223 | if (PageUptodate(src) && !PageUptodate(dst)) | |
224 | SetPageUptodate(dst); | |
225 | else if (!PageUptodate(src) && PageUptodate(dst)) | |
226 | ClearPageUptodate(dst); | |
227 | if (PageMappedToDisk(src) && !PageMappedToDisk(dst)) | |
228 | SetPageMappedToDisk(dst); | |
229 | else if (!PageMappedToDisk(src) && PageMappedToDisk(dst)) | |
230 | ClearPageMappedToDisk(dst); | |
231 | ||
232 | do { | |
233 | unlock_buffer(sbh); | |
234 | unlock_buffer(dbh); | |
235 | sbh = sbh->b_this_page; | |
236 | dbh = dbh->b_this_page; | |
237 | } while (dbh != dbufs); | |
238 | } | |
239 | ||
240 | int nilfs_copy_dirty_pages(struct address_space *dmap, | |
241 | struct address_space *smap) | |
242 | { | |
243 | struct pagevec pvec; | |
244 | unsigned int i; | |
245 | pgoff_t index = 0; | |
246 | int err = 0; | |
247 | ||
86679820 | 248 | pagevec_init(&pvec); |
0bd49f94 | 249 | repeat: |
67fd707f | 250 | if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY)) |
0bd49f94 RK |
251 | return 0; |
252 | ||
253 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
254 | struct page *page = pvec.pages[i], *dpage; | |
255 | ||
256 | lock_page(page); | |
257 | if (unlikely(!PageDirty(page))) | |
258 | NILFS_PAGE_BUG(page, "inconsistent dirty state"); | |
259 | ||
260 | dpage = grab_cache_page(dmap, page->index); | |
261 | if (unlikely(!dpage)) { | |
262 | /* No empty page is added to the page cache */ | |
263 | err = -ENOMEM; | |
264 | unlock_page(page); | |
265 | break; | |
266 | } | |
267 | if (unlikely(!page_has_buffers(page))) | |
268 | NILFS_PAGE_BUG(page, | |
269 | "found empty page in dat page cache"); | |
270 | ||
271 | nilfs_copy_page(dpage, page, 1); | |
272 | __set_page_dirty_nobuffers(dpage); | |
273 | ||
274 | unlock_page(dpage); | |
09cbfeaf | 275 | put_page(dpage); |
0bd49f94 RK |
276 | unlock_page(page); |
277 | } | |
278 | pagevec_release(&pvec); | |
279 | cond_resched(); | |
280 | ||
281 | if (likely(!err)) | |
282 | goto repeat; | |
283 | return err; | |
284 | } | |
285 | ||
286 | /** | |
7a65004b | 287 | * nilfs_copy_back_pages -- copy back pages to original cache from shadow cache |
0bd49f94 RK |
288 | * @dmap: destination page cache |
289 | * @smap: source page cache | |
290 | * | |
f611ff63 | 291 | * No pages must be added to the cache during this process. |
0bd49f94 RK |
292 | * This must be ensured by the caller. |
293 | */ | |
294 | void nilfs_copy_back_pages(struct address_space *dmap, | |
295 | struct address_space *smap) | |
296 | { | |
297 | struct pagevec pvec; | |
298 | unsigned int i, n; | |
299 | pgoff_t index = 0; | |
0bd49f94 | 300 | |
86679820 | 301 | pagevec_init(&pvec); |
0bd49f94 | 302 | repeat: |
397162ff | 303 | n = pagevec_lookup(&pvec, smap, &index); |
0bd49f94 RK |
304 | if (!n) |
305 | return; | |
0bd49f94 RK |
306 | |
307 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
308 | struct page *page = pvec.pages[i], *dpage; | |
309 | pgoff_t offset = page->index; | |
310 | ||
311 | lock_page(page); | |
312 | dpage = find_lock_page(dmap, offset); | |
313 | if (dpage) { | |
f611ff63 | 314 | /* overwrite existing page in the destination cache */ |
1f5abe7e | 315 | WARN_ON(PageDirty(dpage)); |
0bd49f94 RK |
316 | nilfs_copy_page(dpage, page, 0); |
317 | unlock_page(dpage); | |
09cbfeaf | 318 | put_page(dpage); |
f611ff63 | 319 | /* Do we not need to remove page from smap here? */ |
0bd49f94 | 320 | } else { |
f611ff63 | 321 | struct page *p; |
0bd49f94 RK |
322 | |
323 | /* move the page to the destination cache */ | |
b93b0163 | 324 | xa_lock_irq(&smap->i_pages); |
f611ff63 MW |
325 | p = __xa_erase(&smap->i_pages, offset); |
326 | WARN_ON(page != p); | |
0bd49f94 | 327 | smap->nrpages--; |
b93b0163 | 328 | xa_unlock_irq(&smap->i_pages); |
0bd49f94 | 329 | |
b93b0163 | 330 | xa_lock_irq(&dmap->i_pages); |
f611ff63 MW |
331 | p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS); |
332 | if (unlikely(p)) { | |
333 | /* Probably -ENOMEM */ | |
0bd49f94 | 334 | page->mapping = NULL; |
f611ff63 | 335 | put_page(page); |
0bd49f94 RK |
336 | } else { |
337 | page->mapping = dmap; | |
338 | dmap->nrpages++; | |
339 | if (PageDirty(page)) | |
f611ff63 MW |
340 | __xa_set_mark(&dmap->i_pages, offset, |
341 | PAGECACHE_TAG_DIRTY); | |
0bd49f94 | 342 | } |
b93b0163 | 343 | xa_unlock_irq(&dmap->i_pages); |
0bd49f94 RK |
344 | } |
345 | unlock_page(page); | |
346 | } | |
347 | pagevec_release(&pvec); | |
348 | cond_resched(); | |
349 | ||
350 | goto repeat; | |
351 | } | |
352 | ||
8c26c4e2 VD |
353 | /** |
354 | * nilfs_clear_dirty_pages - discard dirty pages in address space | |
355 | * @mapping: address space with dirty pages for discarding | |
356 | * @silent: suppress [true] or print [false] warning messages | |
357 | */ | |
358 | void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent) | |
0bd49f94 RK |
359 | { |
360 | struct pagevec pvec; | |
361 | unsigned int i; | |
362 | pgoff_t index = 0; | |
363 | ||
86679820 | 364 | pagevec_init(&pvec); |
0bd49f94 | 365 | |
67fd707f JK |
366 | while (pagevec_lookup_tag(&pvec, mapping, &index, |
367 | PAGECACHE_TAG_DIRTY)) { | |
0bd49f94 RK |
368 | for (i = 0; i < pagevec_count(&pvec); i++) { |
369 | struct page *page = pvec.pages[i]; | |
0bd49f94 RK |
370 | |
371 | lock_page(page); | |
8c26c4e2 | 372 | nilfs_clear_dirty_page(page, silent); |
0bd49f94 RK |
373 | unlock_page(page); |
374 | } | |
375 | pagevec_release(&pvec); | |
376 | cond_resched(); | |
377 | } | |
378 | } | |
379 | ||
8c26c4e2 VD |
380 | /** |
381 | * nilfs_clear_dirty_page - discard dirty page | |
382 | * @page: dirty page that will be discarded | |
383 | * @silent: suppress [true] or print [false] warning messages | |
384 | */ | |
385 | void nilfs_clear_dirty_page(struct page *page, bool silent) | |
386 | { | |
387 | struct inode *inode = page->mapping->host; | |
388 | struct super_block *sb = inode->i_sb; | |
389 | ||
dc33f5f3 | 390 | BUG_ON(!PageLocked(page)); |
8c26c4e2 | 391 | |
d6517deb | 392 | if (!silent) |
a1d0747a JP |
393 | nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu", |
394 | page_offset(page), inode->i_ino); | |
8c26c4e2 VD |
395 | |
396 | ClearPageUptodate(page); | |
397 | ClearPageMappedToDisk(page); | |
398 | ||
399 | if (page_has_buffers(page)) { | |
400 | struct buffer_head *bh, *head; | |
ead8ecff | 401 | const unsigned long clear_bits = |
4ce5c342 RK |
402 | (BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) | |
403 | BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) | | |
404 | BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected)); | |
8c26c4e2 VD |
405 | |
406 | bh = head = page_buffers(page); | |
407 | do { | |
408 | lock_buffer(bh); | |
d6517deb | 409 | if (!silent) |
a1d0747a JP |
410 | nilfs_warn(sb, |
411 | "discard dirty block: blocknr=%llu, size=%zu", | |
412 | (u64)bh->b_blocknr, bh->b_size); | |
d6517deb | 413 | |
ead8ecff | 414 | set_mask_bits(&bh->b_state, clear_bits, 0); |
8c26c4e2 VD |
415 | unlock_buffer(bh); |
416 | } while (bh = bh->b_this_page, bh != head); | |
417 | } | |
418 | ||
419 | __nilfs_clear_page_dirty(page); | |
420 | } | |
421 | ||
0c6c44cb RK |
422 | unsigned int nilfs_page_count_clean_buffers(struct page *page, |
423 | unsigned int from, unsigned int to) | |
0bd49f94 | 424 | { |
0c6c44cb | 425 | unsigned int block_start, block_end; |
0bd49f94 | 426 | struct buffer_head *bh, *head; |
0c6c44cb | 427 | unsigned int nc = 0; |
0bd49f94 RK |
428 | |
429 | for (bh = head = page_buffers(page), block_start = 0; | |
430 | bh != head || !block_start; | |
431 | block_start = block_end, bh = bh->b_this_page) { | |
432 | block_end = block_start + bh->b_size; | |
433 | if (block_end > from && block_start < to && !buffer_dirty(bh)) | |
434 | nc++; | |
435 | } | |
436 | return nc; | |
437 | } | |
ae53a0a2 | 438 | |
b83ae6d4 | 439 | void nilfs_mapping_init(struct address_space *mapping, struct inode *inode) |
ebdfed4d | 440 | { |
aa405b1f | 441 | mapping->host = inode; |
ebdfed4d RK |
442 | mapping->flags = 0; |
443 | mapping_set_gfp_mask(mapping, GFP_NOFS); | |
252aa6f5 | 444 | mapping->private_data = NULL; |
d611b22f | 445 | mapping->a_ops = &empty_aops; |
ebdfed4d | 446 | } |
0bd49f94 RK |
447 | |
448 | /* | |
449 | * NILFS2 needs clear_page_dirty() in the following two cases: | |
450 | * | |
451 | * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears | |
452 | * page dirty flags when it copies back pages from the shadow cache | |
453 | * (gcdat->{i_mapping,i_btnode_cache}) to its original cache | |
454 | * (dat->{i_mapping,i_btnode_cache}). | |
455 | * | |
456 | * 2) Some B-tree operations like insertion or deletion may dispose buffers | |
457 | * in dirty state, and this needs to cancel the dirty state of their pages. | |
458 | */ | |
459 | int __nilfs_clear_page_dirty(struct page *page) | |
460 | { | |
461 | struct address_space *mapping = page->mapping; | |
462 | ||
463 | if (mapping) { | |
b93b0163 | 464 | xa_lock_irq(&mapping->i_pages); |
0bd49f94 | 465 | if (test_bit(PG_dirty, &page->flags)) { |
f611ff63 | 466 | __xa_clear_mark(&mapping->i_pages, page_index(page), |
0bd49f94 | 467 | PAGECACHE_TAG_DIRTY); |
b93b0163 | 468 | xa_unlock_irq(&mapping->i_pages); |
0bd49f94 RK |
469 | return clear_page_dirty_for_io(page); |
470 | } | |
b93b0163 | 471 | xa_unlock_irq(&mapping->i_pages); |
0bd49f94 RK |
472 | return 0; |
473 | } | |
474 | return TestClearPageDirty(page); | |
475 | } | |
622daaff RK |
476 | |
477 | /** | |
478 | * nilfs_find_uncommitted_extent - find extent of uncommitted data | |
479 | * @inode: inode | |
480 | * @start_blk: start block offset (in) | |
481 | * @blkoff: start offset of the found extent (out) | |
482 | * | |
483 | * This function searches an extent of buffers marked "delayed" which | |
484 | * starts from a block offset equal to or larger than @start_blk. If | |
485 | * such an extent was found, this will store the start offset in | |
486 | * @blkoff and return its length in blocks. Otherwise, zero is | |
487 | * returned. | |
488 | */ | |
489 | unsigned long nilfs_find_uncommitted_extent(struct inode *inode, | |
490 | sector_t start_blk, | |
491 | sector_t *blkoff) | |
492 | { | |
493 | unsigned int i; | |
494 | pgoff_t index; | |
495 | unsigned int nblocks_in_page; | |
496 | unsigned long length = 0; | |
497 | sector_t b; | |
498 | struct pagevec pvec; | |
499 | struct page *page; | |
500 | ||
501 | if (inode->i_mapping->nrpages == 0) | |
502 | return 0; | |
503 | ||
09cbfeaf KS |
504 | index = start_blk >> (PAGE_SHIFT - inode->i_blkbits); |
505 | nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits); | |
622daaff | 506 | |
86679820 | 507 | pagevec_init(&pvec); |
622daaff RK |
508 | |
509 | repeat: | |
510 | pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE, | |
511 | pvec.pages); | |
512 | if (pvec.nr == 0) | |
513 | return length; | |
514 | ||
515 | if (length > 0 && pvec.pages[0]->index > index) | |
516 | goto out; | |
517 | ||
09cbfeaf | 518 | b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits); |
622daaff RK |
519 | i = 0; |
520 | do { | |
521 | page = pvec.pages[i]; | |
522 | ||
523 | lock_page(page); | |
524 | if (page_has_buffers(page)) { | |
525 | struct buffer_head *bh, *head; | |
526 | ||
527 | bh = head = page_buffers(page); | |
528 | do { | |
529 | if (b < start_blk) | |
530 | continue; | |
531 | if (buffer_delay(bh)) { | |
532 | if (length == 0) | |
533 | *blkoff = b; | |
534 | length++; | |
535 | } else if (length > 0) { | |
536 | goto out_locked; | |
537 | } | |
538 | } while (++b, bh = bh->b_this_page, bh != head); | |
539 | } else { | |
540 | if (length > 0) | |
541 | goto out_locked; | |
542 | ||
543 | b += nblocks_in_page; | |
544 | } | |
545 | unlock_page(page); | |
546 | ||
547 | } while (++i < pagevec_count(&pvec)); | |
548 | ||
549 | index = page->index + 1; | |
550 | pagevec_release(&pvec); | |
551 | cond_resched(); | |
552 | goto repeat; | |
553 | ||
554 | out_locked: | |
555 | unlock_page(page); | |
556 | out: | |
557 | pagevec_release(&pvec); | |
558 | return length; | |
559 | } |