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c8b97818 CM |
1 | /* |
2 | * Copyright (C) 2008 Oracle. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/bio.h> | |
21 | #include <linux/buffer_head.h> | |
22 | #include <linux/file.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/pagemap.h> | |
25 | #include <linux/highmem.h> | |
26 | #include <linux/time.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/smp_lock.h> | |
30 | #include <linux/backing-dev.h> | |
31 | #include <linux/mpage.h> | |
32 | #include <linux/swap.h> | |
33 | #include <linux/writeback.h> | |
34 | #include <linux/bit_spinlock.h> | |
35 | #include <linux/version.h> | |
771ed689 | 36 | #include <linux/pagevec.h> |
c8b97818 CM |
37 | #include "ctree.h" |
38 | #include "disk-io.h" | |
39 | #include "transaction.h" | |
40 | #include "btrfs_inode.h" | |
41 | #include "volumes.h" | |
42 | #include "ordered-data.h" | |
43 | #include "compat.h" | |
44 | #include "compression.h" | |
45 | #include "extent_io.h" | |
46 | #include "extent_map.h" | |
47 | ||
48 | struct compressed_bio { | |
49 | /* number of bios pending for this compressed extent */ | |
50 | atomic_t pending_bios; | |
51 | ||
52 | /* the pages with the compressed data on them */ | |
53 | struct page **compressed_pages; | |
54 | ||
55 | /* inode that owns this data */ | |
56 | struct inode *inode; | |
57 | ||
58 | /* starting offset in the inode for our pages */ | |
59 | u64 start; | |
60 | ||
61 | /* number of bytes in the inode we're working on */ | |
62 | unsigned long len; | |
63 | ||
64 | /* number of bytes on disk */ | |
65 | unsigned long compressed_len; | |
66 | ||
67 | /* number of compressed pages in the array */ | |
68 | unsigned long nr_pages; | |
69 | ||
70 | /* IO errors */ | |
71 | int errors; | |
72 | ||
73 | /* for reads, this is the bio we are copying the data into */ | |
74 | struct bio *orig_bio; | |
75 | }; | |
76 | ||
77 | static struct bio *compressed_bio_alloc(struct block_device *bdev, | |
78 | u64 first_byte, gfp_t gfp_flags) | |
79 | { | |
80 | struct bio *bio; | |
81 | int nr_vecs; | |
82 | ||
83 | nr_vecs = bio_get_nr_vecs(bdev); | |
84 | bio = bio_alloc(gfp_flags, nr_vecs); | |
85 | ||
86 | if (bio == NULL && (current->flags & PF_MEMALLOC)) { | |
87 | while (!bio && (nr_vecs /= 2)) | |
88 | bio = bio_alloc(gfp_flags, nr_vecs); | |
89 | } | |
90 | ||
91 | if (bio) { | |
92 | bio->bi_size = 0; | |
93 | bio->bi_bdev = bdev; | |
94 | bio->bi_sector = first_byte >> 9; | |
95 | } | |
96 | return bio; | |
97 | } | |
98 | ||
99 | /* when we finish reading compressed pages from the disk, we | |
100 | * decompress them and then run the bio end_io routines on the | |
101 | * decompressed pages (in the inode address space). | |
102 | * | |
103 | * This allows the checksumming and other IO error handling routines | |
104 | * to work normally | |
105 | * | |
106 | * The compressed pages are freed here, and it must be run | |
107 | * in process context | |
108 | */ | |
109 | static void end_compressed_bio_read(struct bio *bio, int err) | |
110 | { | |
111 | struct extent_io_tree *tree; | |
112 | struct compressed_bio *cb = bio->bi_private; | |
113 | struct inode *inode; | |
114 | struct page *page; | |
115 | unsigned long index; | |
116 | int ret; | |
117 | ||
118 | if (err) | |
119 | cb->errors = 1; | |
120 | ||
121 | /* if there are more bios still pending for this compressed | |
122 | * extent, just exit | |
123 | */ | |
124 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
125 | goto out; | |
126 | ||
127 | /* ok, we're the last bio for this extent, lets start | |
128 | * the decompression. | |
129 | */ | |
130 | inode = cb->inode; | |
131 | tree = &BTRFS_I(inode)->io_tree; | |
132 | ret = btrfs_zlib_decompress_biovec(cb->compressed_pages, | |
133 | cb->start, | |
134 | cb->orig_bio->bi_io_vec, | |
135 | cb->orig_bio->bi_vcnt, | |
136 | cb->compressed_len); | |
137 | if (ret) | |
138 | cb->errors = 1; | |
139 | ||
140 | /* release the compressed pages */ | |
141 | index = 0; | |
142 | for (index = 0; index < cb->nr_pages; index++) { | |
143 | page = cb->compressed_pages[index]; | |
144 | page->mapping = NULL; | |
145 | page_cache_release(page); | |
146 | } | |
147 | ||
148 | /* do io completion on the original bio */ | |
771ed689 | 149 | if (cb->errors) { |
c8b97818 | 150 | bio_io_error(cb->orig_bio); |
771ed689 | 151 | } else |
c8b97818 CM |
152 | bio_endio(cb->orig_bio, 0); |
153 | ||
154 | /* finally free the cb struct */ | |
155 | kfree(cb->compressed_pages); | |
156 | kfree(cb); | |
157 | out: | |
158 | bio_put(bio); | |
159 | } | |
160 | ||
161 | /* | |
162 | * Clear the writeback bits on all of the file | |
163 | * pages for a compressed write | |
164 | */ | |
165 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, | |
166 | unsigned long ram_size) | |
167 | { | |
168 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
169 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
170 | struct page *pages[16]; | |
171 | unsigned long nr_pages = end_index - index + 1; | |
172 | int i; | |
173 | int ret; | |
174 | ||
175 | while(nr_pages > 0) { | |
176 | ret = find_get_pages_contig(inode->i_mapping, index, | |
177 | min(nr_pages, ARRAY_SIZE(pages)), pages); | |
178 | if (ret == 0) { | |
179 | nr_pages -= 1; | |
180 | index += 1; | |
181 | continue; | |
182 | } | |
183 | for (i = 0; i < ret; i++) { | |
184 | end_page_writeback(pages[i]); | |
185 | page_cache_release(pages[i]); | |
186 | } | |
187 | nr_pages -= ret; | |
188 | index += ret; | |
189 | } | |
190 | /* the inode may be gone now */ | |
191 | return 0; | |
192 | } | |
193 | ||
194 | /* | |
195 | * do the cleanup once all the compressed pages hit the disk. | |
196 | * This will clear writeback on the file pages and free the compressed | |
197 | * pages. | |
198 | * | |
199 | * This also calls the writeback end hooks for the file pages so that | |
200 | * metadata and checksums can be updated in the file. | |
201 | */ | |
202 | static void end_compressed_bio_write(struct bio *bio, int err) | |
203 | { | |
204 | struct extent_io_tree *tree; | |
205 | struct compressed_bio *cb = bio->bi_private; | |
206 | struct inode *inode; | |
207 | struct page *page; | |
208 | unsigned long index; | |
209 | ||
210 | if (err) | |
211 | cb->errors = 1; | |
212 | ||
213 | /* if there are more bios still pending for this compressed | |
214 | * extent, just exit | |
215 | */ | |
216 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
217 | goto out; | |
218 | ||
219 | /* ok, we're the last bio for this extent, step one is to | |
220 | * call back into the FS and do all the end_io operations | |
221 | */ | |
222 | inode = cb->inode; | |
223 | tree = &BTRFS_I(inode)->io_tree; | |
70b99e69 | 224 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
c8b97818 CM |
225 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
226 | cb->start, | |
227 | cb->start + cb->len - 1, | |
228 | NULL, 1); | |
70b99e69 | 229 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 CM |
230 | |
231 | end_compressed_writeback(inode, cb->start, cb->len); | |
232 | /* note, our inode could be gone now */ | |
233 | ||
234 | /* | |
235 | * release the compressed pages, these came from alloc_page and | |
236 | * are not attached to the inode at all | |
237 | */ | |
238 | index = 0; | |
239 | for (index = 0; index < cb->nr_pages; index++) { | |
240 | page = cb->compressed_pages[index]; | |
241 | page->mapping = NULL; | |
242 | page_cache_release(page); | |
243 | } | |
244 | ||
245 | /* finally free the cb struct */ | |
246 | kfree(cb->compressed_pages); | |
247 | kfree(cb); | |
248 | out: | |
249 | bio_put(bio); | |
250 | } | |
251 | ||
252 | /* | |
253 | * worker function to build and submit bios for previously compressed pages. | |
254 | * The corresponding pages in the inode should be marked for writeback | |
255 | * and the compressed pages should have a reference on them for dropping | |
256 | * when the IO is complete. | |
257 | * | |
258 | * This also checksums the file bytes and gets things ready for | |
259 | * the end io hooks. | |
260 | */ | |
261 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
262 | unsigned long len, u64 disk_start, | |
263 | unsigned long compressed_len, | |
264 | struct page **compressed_pages, | |
265 | unsigned long nr_pages) | |
266 | { | |
267 | struct bio *bio = NULL; | |
268 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
269 | struct compressed_bio *cb; | |
270 | unsigned long bytes_left; | |
271 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
272 | int page_index = 0; | |
273 | struct page *page; | |
274 | u64 first_byte = disk_start; | |
275 | struct block_device *bdev; | |
276 | int ret; | |
277 | ||
278 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
279 | cb = kmalloc(sizeof(*cb), GFP_NOFS); | |
280 | atomic_set(&cb->pending_bios, 0); | |
281 | cb->errors = 0; | |
282 | cb->inode = inode; | |
283 | cb->start = start; | |
284 | cb->len = len; | |
285 | cb->compressed_pages = compressed_pages; | |
286 | cb->compressed_len = compressed_len; | |
287 | cb->orig_bio = NULL; | |
288 | cb->nr_pages = nr_pages; | |
289 | ||
290 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
291 | ||
292 | ret = btrfs_csum_file_bytes(root, inode, start, len); | |
293 | BUG_ON(ret); | |
294 | ||
295 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
296 | bio->bi_private = cb; | |
297 | bio->bi_end_io = end_compressed_bio_write; | |
298 | atomic_inc(&cb->pending_bios); | |
299 | ||
300 | /* create and submit bios for the compressed pages */ | |
301 | bytes_left = compressed_len; | |
cfbc246e | 302 | for (page_index = 0; page_index < cb->nr_pages; page_index++) { |
c8b97818 CM |
303 | page = compressed_pages[page_index]; |
304 | page->mapping = inode->i_mapping; | |
305 | if (bio->bi_size) | |
306 | ret = io_tree->ops->merge_bio_hook(page, 0, | |
307 | PAGE_CACHE_SIZE, | |
308 | bio, 0); | |
309 | else | |
310 | ret = 0; | |
311 | ||
70b99e69 | 312 | page->mapping = NULL; |
c8b97818 CM |
313 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < |
314 | PAGE_CACHE_SIZE) { | |
315 | bio_get(bio); | |
316 | ||
317 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
318 | BUG_ON(ret); | |
319 | ||
320 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); | |
321 | BUG_ON(ret); | |
322 | ||
323 | bio_put(bio); | |
324 | ||
325 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
326 | atomic_inc(&cb->pending_bios); | |
327 | bio->bi_private = cb; | |
328 | bio->bi_end_io = end_compressed_bio_write; | |
329 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
330 | } | |
cfbc246e CM |
331 | if (bytes_left < PAGE_CACHE_SIZE) { |
332 | printk("bytes left %lu compress len %lu nr %lu\n", | |
333 | bytes_left, cb->compressed_len, cb->nr_pages); | |
334 | } | |
c8b97818 CM |
335 | bytes_left -= PAGE_CACHE_SIZE; |
336 | first_byte += PAGE_CACHE_SIZE; | |
771ed689 | 337 | cond_resched(); |
c8b97818 CM |
338 | } |
339 | bio_get(bio); | |
340 | ||
341 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
342 | BUG_ON(ret); | |
343 | ||
344 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); | |
345 | BUG_ON(ret); | |
346 | ||
347 | bio_put(bio); | |
348 | return 0; | |
349 | } | |
350 | ||
771ed689 CM |
351 | static noinline int add_ra_bio_pages(struct inode *inode, |
352 | u64 compressed_end, | |
353 | struct compressed_bio *cb) | |
354 | { | |
355 | unsigned long end_index; | |
356 | unsigned long page_index; | |
357 | u64 last_offset; | |
358 | u64 isize = i_size_read(inode); | |
359 | int ret; | |
360 | struct page *page; | |
361 | unsigned long nr_pages = 0; | |
362 | struct extent_map *em; | |
363 | struct address_space *mapping = inode->i_mapping; | |
364 | struct pagevec pvec; | |
365 | struct extent_map_tree *em_tree; | |
366 | struct extent_io_tree *tree; | |
367 | u64 end; | |
368 | int misses = 0; | |
369 | ||
370 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; | |
371 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); | |
372 | em_tree = &BTRFS_I(inode)->extent_tree; | |
373 | tree = &BTRFS_I(inode)->io_tree; | |
374 | ||
375 | if (isize == 0) | |
376 | return 0; | |
377 | ||
378 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; | |
379 | ||
380 | pagevec_init(&pvec, 0); | |
381 | while(last_offset < compressed_end) { | |
382 | page_index = last_offset >> PAGE_CACHE_SHIFT; | |
383 | ||
384 | if (page_index > end_index) | |
385 | break; | |
386 | ||
387 | rcu_read_lock(); | |
388 | page = radix_tree_lookup(&mapping->page_tree, page_index); | |
389 | rcu_read_unlock(); | |
390 | if (page) { | |
391 | misses++; | |
392 | if (misses > 4) | |
393 | break; | |
394 | goto next; | |
395 | } | |
396 | ||
397 | page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS); | |
398 | if (!page) | |
399 | break; | |
400 | ||
401 | page->index = page_index; | |
402 | /* | |
403 | * what we want to do here is call add_to_page_cache_lru, | |
404 | * but that isn't exported, so we reproduce it here | |
405 | */ | |
406 | if (add_to_page_cache(page, mapping, | |
407 | page->index, GFP_NOFS)) { | |
408 | page_cache_release(page); | |
409 | goto next; | |
410 | } | |
411 | ||
412 | /* open coding of lru_cache_add, also not exported */ | |
413 | page_cache_get(page); | |
414 | if (!pagevec_add(&pvec, page)) | |
415 | __pagevec_lru_add(&pvec); | |
416 | ||
417 | end = last_offset + PAGE_CACHE_SIZE - 1; | |
418 | /* | |
419 | * at this point, we have a locked page in the page cache | |
420 | * for these bytes in the file. But, we have to make | |
421 | * sure they map to this compressed extent on disk. | |
422 | */ | |
423 | set_page_extent_mapped(page); | |
424 | lock_extent(tree, last_offset, end, GFP_NOFS); | |
425 | spin_lock(&em_tree->lock); | |
426 | em = lookup_extent_mapping(em_tree, last_offset, | |
427 | PAGE_CACHE_SIZE); | |
428 | spin_unlock(&em_tree->lock); | |
429 | ||
430 | if (!em || last_offset < em->start || | |
431 | (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || | |
432 | (em->block_start >> 9) != cb->orig_bio->bi_sector) { | |
433 | free_extent_map(em); | |
434 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
435 | unlock_page(page); | |
436 | page_cache_release(page); | |
437 | break; | |
438 | } | |
439 | free_extent_map(em); | |
440 | ||
441 | if (page->index == end_index) { | |
442 | char *userpage; | |
443 | size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); | |
444 | ||
445 | if (zero_offset) { | |
446 | int zeros; | |
447 | zeros = PAGE_CACHE_SIZE - zero_offset; | |
448 | userpage = kmap_atomic(page, KM_USER0); | |
449 | memset(userpage + zero_offset, 0, zeros); | |
450 | flush_dcache_page(page); | |
451 | kunmap_atomic(userpage, KM_USER0); | |
452 | } | |
453 | } | |
454 | ||
455 | ret = bio_add_page(cb->orig_bio, page, | |
456 | PAGE_CACHE_SIZE, 0); | |
457 | ||
458 | if (ret == PAGE_CACHE_SIZE) { | |
459 | nr_pages++; | |
460 | page_cache_release(page); | |
461 | } else { | |
462 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
463 | unlock_page(page); | |
464 | page_cache_release(page); | |
465 | break; | |
466 | } | |
467 | next: | |
468 | last_offset += PAGE_CACHE_SIZE; | |
469 | } | |
470 | if (pagevec_count(&pvec)) | |
471 | __pagevec_lru_add(&pvec); | |
472 | return 0; | |
473 | } | |
474 | ||
c8b97818 CM |
475 | /* |
476 | * for a compressed read, the bio we get passed has all the inode pages | |
477 | * in it. We don't actually do IO on those pages but allocate new ones | |
478 | * to hold the compressed pages on disk. | |
479 | * | |
480 | * bio->bi_sector points to the compressed extent on disk | |
481 | * bio->bi_io_vec points to all of the inode pages | |
482 | * bio->bi_vcnt is a count of pages | |
483 | * | |
484 | * After the compressed pages are read, we copy the bytes into the | |
485 | * bio we were passed and then call the bio end_io calls | |
486 | */ | |
487 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
488 | int mirror_num, unsigned long bio_flags) | |
489 | { | |
490 | struct extent_io_tree *tree; | |
491 | struct extent_map_tree *em_tree; | |
492 | struct compressed_bio *cb; | |
493 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
494 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
495 | unsigned long compressed_len; | |
496 | unsigned long nr_pages; | |
497 | unsigned long page_index; | |
498 | struct page *page; | |
499 | struct block_device *bdev; | |
500 | struct bio *comp_bio; | |
501 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; | |
771ed689 | 502 | u64 em_len; |
c8b97818 CM |
503 | struct extent_map *em; |
504 | int ret; | |
505 | ||
506 | tree = &BTRFS_I(inode)->io_tree; | |
507 | em_tree = &BTRFS_I(inode)->extent_tree; | |
508 | ||
509 | /* we need the actual starting offset of this extent in the file */ | |
510 | spin_lock(&em_tree->lock); | |
511 | em = lookup_extent_mapping(em_tree, | |
512 | page_offset(bio->bi_io_vec->bv_page), | |
513 | PAGE_CACHE_SIZE); | |
514 | spin_unlock(&em_tree->lock); | |
515 | ||
516 | cb = kmalloc(sizeof(*cb), GFP_NOFS); | |
517 | atomic_set(&cb->pending_bios, 0); | |
518 | cb->errors = 0; | |
519 | cb->inode = inode; | |
520 | ||
521 | cb->start = em->start; | |
522 | compressed_len = em->block_len; | |
771ed689 | 523 | em_len = em->len; |
c8b97818 CM |
524 | free_extent_map(em); |
525 | ||
526 | cb->len = uncompressed_len; | |
527 | cb->compressed_len = compressed_len; | |
528 | cb->orig_bio = bio; | |
529 | ||
530 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
531 | PAGE_CACHE_SIZE; | |
532 | cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages, | |
533 | GFP_NOFS); | |
534 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
535 | ||
536 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
537 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | | |
538 | __GFP_HIGHMEM); | |
539 | } | |
540 | cb->nr_pages = nr_pages; | |
541 | ||
771ed689 CM |
542 | add_ra_bio_pages(inode, cb->start + em_len, cb); |
543 | ||
544 | if (!btrfs_test_opt(root, NODATASUM) && | |
545 | !btrfs_test_flag(inode, NODATASUM)) { | |
546 | btrfs_lookup_bio_sums(root, inode, cb->orig_bio); | |
547 | } | |
548 | ||
549 | /* include any pages we added in add_ra-bio_pages */ | |
550 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
551 | cb->len = uncompressed_len; | |
552 | ||
c8b97818 CM |
553 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
554 | comp_bio->bi_private = cb; | |
555 | comp_bio->bi_end_io = end_compressed_bio_read; | |
556 | atomic_inc(&cb->pending_bios); | |
557 | ||
558 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
559 | page = cb->compressed_pages[page_index]; | |
560 | page->mapping = inode->i_mapping; | |
561 | if (comp_bio->bi_size) | |
562 | ret = tree->ops->merge_bio_hook(page, 0, | |
563 | PAGE_CACHE_SIZE, | |
564 | comp_bio, 0); | |
565 | else | |
566 | ret = 0; | |
567 | ||
70b99e69 | 568 | page->mapping = NULL; |
c8b97818 CM |
569 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < |
570 | PAGE_CACHE_SIZE) { | |
571 | bio_get(comp_bio); | |
572 | ||
573 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
574 | BUG_ON(ret); | |
575 | ||
576 | ret = btrfs_map_bio(root, READ, comp_bio, 0, 0); | |
577 | BUG_ON(ret); | |
578 | ||
579 | bio_put(comp_bio); | |
580 | ||
581 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
582 | GFP_NOFS); | |
583 | atomic_inc(&cb->pending_bios); | |
771ed689 CM |
584 | comp_bio->bi_private = cb; |
585 | comp_bio->bi_end_io = end_compressed_bio_read; | |
586 | ||
587 | bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); | |
c8b97818 CM |
588 | } |
589 | cur_disk_byte += PAGE_CACHE_SIZE; | |
590 | } | |
591 | bio_get(comp_bio); | |
592 | ||
593 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
594 | BUG_ON(ret); | |
595 | ||
596 | ret = btrfs_map_bio(root, READ, comp_bio, 0, 0); | |
597 | BUG_ON(ret); | |
598 | ||
599 | bio_put(comp_bio); | |
600 | return 0; | |
601 | } |