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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/backing-dev.h>
30#include <linux/mpage.h>
31#include <linux/swap.h>
32#include <linux/writeback.h>
33#include <linux/bit_spinlock.h>
34#include <linux/slab.h>
35#include "ctree.h"
36#include "disk-io.h"
37#include "transaction.h"
38#include "btrfs_inode.h"
39#include "volumes.h"
40#include "ordered-data.h"
41#include "compression.h"
42#include "extent_io.h"
43#include "extent_map.h"
44
45struct compressed_bio {
46
47 atomic_t pending_bios;
48
49
50 struct page **compressed_pages;
51
52
53 struct inode *inode;
54
55
56 u64 start;
57
58
59 unsigned long len;
60
61
62 unsigned long compressed_len;
63
64
65 int compress_type;
66
67
68 unsigned long nr_pages;
69
70
71 int errors;
72 int mirror_num;
73
74
75 struct bio *orig_bio;
76
77
78
79
80
81 u32 sums;
82};
83
84static int btrfs_decompress_biovec(int type, struct page **pages_in,
85 u64 disk_start, struct bio_vec *bvec,
86 int vcnt, size_t srclen);
87
88static inline int compressed_bio_size(struct btrfs_root *root,
89 unsigned long disk_size)
90{
91 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
92
93 return sizeof(struct compressed_bio) +
94 (DIV_ROUND_UP(disk_size, root->sectorsize)) * csum_size;
95}
96
97static struct bio *compressed_bio_alloc(struct block_device *bdev,
98 u64 first_byte, gfp_t gfp_flags)
99{
100 return btrfs_bio_alloc(bdev, first_byte >> 9, BIO_MAX_PAGES, gfp_flags);
101}
102
103static int check_compressed_csum(struct inode *inode,
104 struct compressed_bio *cb,
105 u64 disk_start)
106{
107 int ret;
108 struct page *page;
109 unsigned long i;
110 char *kaddr;
111 u32 csum;
112 u32 *cb_sum = &cb->sums;
113
114 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
115 return 0;
116
117 for (i = 0; i < cb->nr_pages; i++) {
118 page = cb->compressed_pages[i];
119 csum = ~(u32)0;
120
121 kaddr = kmap_atomic(page);
122 csum = btrfs_csum_data(kaddr, csum, PAGE_CACHE_SIZE);
123 btrfs_csum_final(csum, (char *)&csum);
124 kunmap_atomic(kaddr);
125
126 if (csum != *cb_sum) {
127 btrfs_info(BTRFS_I(inode)->root->fs_info,
128 "csum failed ino %llu extent %llu csum %u wanted %u mirror %d",
129 btrfs_ino(inode), disk_start, csum, *cb_sum,
130 cb->mirror_num);
131 ret = -EIO;
132 goto fail;
133 }
134 cb_sum++;
135
136 }
137 ret = 0;
138fail:
139 return ret;
140}
141
142
143
144
145
146
147
148
149
150
151
152static void end_compressed_bio_read(struct bio *bio)
153{
154 struct compressed_bio *cb = bio->bi_private;
155 struct inode *inode;
156 struct page *page;
157 unsigned long index;
158 int ret;
159
160 if (bio->bi_error)
161 cb->errors = 1;
162
163
164
165
166 if (!atomic_dec_and_test(&cb->pending_bios))
167 goto out;
168
169 inode = cb->inode;
170 ret = check_compressed_csum(inode, cb,
171 (u64)bio->bi_iter.bi_sector << 9);
172 if (ret)
173 goto csum_failed;
174
175
176
177
178 ret = btrfs_decompress_biovec(cb->compress_type,
179 cb->compressed_pages,
180 cb->start,
181 cb->orig_bio->bi_io_vec,
182 cb->orig_bio->bi_vcnt,
183 cb->compressed_len);
184csum_failed:
185 if (ret)
186 cb->errors = 1;
187
188
189 index = 0;
190 for (index = 0; index < cb->nr_pages; index++) {
191 page = cb->compressed_pages[index];
192 page->mapping = NULL;
193 page_cache_release(page);
194 }
195
196
197 if (cb->errors) {
198 bio_io_error(cb->orig_bio);
199 } else {
200 int i;
201 struct bio_vec *bvec;
202
203
204
205
206
207 bio_for_each_segment_all(bvec, cb->orig_bio, i)
208 SetPageChecked(bvec->bv_page);
209
210 bio_endio(cb->orig_bio);
211 }
212
213
214 kfree(cb->compressed_pages);
215 kfree(cb);
216out:
217 bio_put(bio);
218}
219
220
221
222
223
224static noinline void end_compressed_writeback(struct inode *inode,
225 const struct compressed_bio *cb)
226{
227 unsigned long index = cb->start >> PAGE_CACHE_SHIFT;
228 unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_CACHE_SHIFT;
229 struct page *pages[16];
230 unsigned long nr_pages = end_index - index + 1;
231 int i;
232 int ret;
233
234 if (cb->errors)
235 mapping_set_error(inode->i_mapping, -EIO);
236
237 while (nr_pages > 0) {
238 ret = find_get_pages_contig(inode->i_mapping, index,
239 min_t(unsigned long,
240 nr_pages, ARRAY_SIZE(pages)), pages);
241 if (ret == 0) {
242 nr_pages -= 1;
243 index += 1;
244 continue;
245 }
246 for (i = 0; i < ret; i++) {
247 if (cb->errors)
248 SetPageError(pages[i]);
249 end_page_writeback(pages[i]);
250 page_cache_release(pages[i]);
251 }
252 nr_pages -= ret;
253 index += ret;
254 }
255
256}
257
258
259
260
261
262
263
264
265
266static void end_compressed_bio_write(struct bio *bio)
267{
268 struct extent_io_tree *tree;
269 struct compressed_bio *cb = bio->bi_private;
270 struct inode *inode;
271 struct page *page;
272 unsigned long index;
273
274 if (bio->bi_error)
275 cb->errors = 1;
276
277
278
279
280 if (!atomic_dec_and_test(&cb->pending_bios))
281 goto out;
282
283
284
285
286 inode = cb->inode;
287 tree = &BTRFS_I(inode)->io_tree;
288 cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
289 tree->ops->writepage_end_io_hook(cb->compressed_pages[0],
290 cb->start,
291 cb->start + cb->len - 1,
292 NULL,
293 bio->bi_error ? 0 : 1);
294 cb->compressed_pages[0]->mapping = NULL;
295
296 end_compressed_writeback(inode, cb);
297
298
299
300
301
302
303 index = 0;
304 for (index = 0; index < cb->nr_pages; index++) {
305 page = cb->compressed_pages[index];
306 page->mapping = NULL;
307 page_cache_release(page);
308 }
309
310
311 kfree(cb->compressed_pages);
312 kfree(cb);
313out:
314 bio_put(bio);
315}
316
317
318
319
320
321
322
323
324
325
326int btrfs_submit_compressed_write(struct inode *inode, u64 start,
327 unsigned long len, u64 disk_start,
328 unsigned long compressed_len,
329 struct page **compressed_pages,
330 unsigned long nr_pages)
331{
332 struct bio *bio = NULL;
333 struct btrfs_root *root = BTRFS_I(inode)->root;
334 struct compressed_bio *cb;
335 unsigned long bytes_left;
336 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
337 int pg_index = 0;
338 struct page *page;
339 u64 first_byte = disk_start;
340 struct block_device *bdev;
341 int ret;
342 int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
343
344 WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
345 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
346 if (!cb)
347 return -ENOMEM;
348 atomic_set(&cb->pending_bios, 0);
349 cb->errors = 0;
350 cb->inode = inode;
351 cb->start = start;
352 cb->len = len;
353 cb->mirror_num = 0;
354 cb->compressed_pages = compressed_pages;
355 cb->compressed_len = compressed_len;
356 cb->orig_bio = NULL;
357 cb->nr_pages = nr_pages;
358
359 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
360
361 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
362 if (!bio) {
363 kfree(cb);
364 return -ENOMEM;
365 }
366 bio->bi_private = cb;
367 bio->bi_end_io = end_compressed_bio_write;
368 atomic_inc(&cb->pending_bios);
369
370
371 bytes_left = compressed_len;
372 for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) {
373 page = compressed_pages[pg_index];
374 page->mapping = inode->i_mapping;
375 if (bio->bi_iter.bi_size)
376 ret = io_tree->ops->merge_bio_hook(WRITE, page, 0,
377 PAGE_CACHE_SIZE,
378 bio, 0);
379 else
380 ret = 0;
381
382 page->mapping = NULL;
383 if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) <
384 PAGE_CACHE_SIZE) {
385 bio_get(bio);
386
387
388
389
390
391
392
393 atomic_inc(&cb->pending_bios);
394 ret = btrfs_bio_wq_end_io(root->fs_info, bio,
395 BTRFS_WQ_ENDIO_DATA);
396 BUG_ON(ret);
397
398 if (!skip_sum) {
399 ret = btrfs_csum_one_bio(root, inode, bio,
400 start, 1);
401 BUG_ON(ret);
402 }
403
404 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
405 BUG_ON(ret);
406
407 bio_put(bio);
408
409 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
410 BUG_ON(!bio);
411 bio->bi_private = cb;
412 bio->bi_end_io = end_compressed_bio_write;
413 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
414 }
415 if (bytes_left < PAGE_CACHE_SIZE) {
416 btrfs_info(BTRFS_I(inode)->root->fs_info,
417 "bytes left %lu compress len %lu nr %lu",
418 bytes_left, cb->compressed_len, cb->nr_pages);
419 }
420 bytes_left -= PAGE_CACHE_SIZE;
421 first_byte += PAGE_CACHE_SIZE;
422 cond_resched();
423 }
424 bio_get(bio);
425
426 ret = btrfs_bio_wq_end_io(root->fs_info, bio, BTRFS_WQ_ENDIO_DATA);
427 BUG_ON(ret);
428
429 if (!skip_sum) {
430 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
431 BUG_ON(ret);
432 }
433
434 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
435 BUG_ON(ret);
436
437 bio_put(bio);
438 return 0;
439}
440
441static noinline int add_ra_bio_pages(struct inode *inode,
442 u64 compressed_end,
443 struct compressed_bio *cb)
444{
445 unsigned long end_index;
446 unsigned long pg_index;
447 u64 last_offset;
448 u64 isize = i_size_read(inode);
449 int ret;
450 struct page *page;
451 unsigned long nr_pages = 0;
452 struct extent_map *em;
453 struct address_space *mapping = inode->i_mapping;
454 struct extent_map_tree *em_tree;
455 struct extent_io_tree *tree;
456 u64 end;
457 int misses = 0;
458
459 page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page;
460 last_offset = (page_offset(page) + PAGE_CACHE_SIZE);
461 em_tree = &BTRFS_I(inode)->extent_tree;
462 tree = &BTRFS_I(inode)->io_tree;
463
464 if (isize == 0)
465 return 0;
466
467 end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
468
469 while (last_offset < compressed_end) {
470 pg_index = last_offset >> PAGE_CACHE_SHIFT;
471
472 if (pg_index > end_index)
473 break;
474
475 rcu_read_lock();
476 page = radix_tree_lookup(&mapping->page_tree, pg_index);
477 rcu_read_unlock();
478 if (page && !radix_tree_exceptional_entry(page)) {
479 misses++;
480 if (misses > 4)
481 break;
482 goto next;
483 }
484
485 page = __page_cache_alloc(mapping_gfp_constraint(mapping,
486 ~__GFP_FS));
487 if (!page)
488 break;
489
490 if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) {
491 page_cache_release(page);
492 goto next;
493 }
494
495 end = last_offset + PAGE_CACHE_SIZE - 1;
496
497
498
499
500
501 set_page_extent_mapped(page);
502 lock_extent(tree, last_offset, end);
503 read_lock(&em_tree->lock);
504 em = lookup_extent_mapping(em_tree, last_offset,
505 PAGE_CACHE_SIZE);
506 read_unlock(&em_tree->lock);
507
508 if (!em || last_offset < em->start ||
509 (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
510 (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) {
511 free_extent_map(em);
512 unlock_extent(tree, last_offset, end);
513 unlock_page(page);
514 page_cache_release(page);
515 break;
516 }
517 free_extent_map(em);
518
519 if (page->index == end_index) {
520 char *userpage;
521 size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1);
522
523 if (zero_offset) {
524 int zeros;
525 zeros = PAGE_CACHE_SIZE - zero_offset;
526 userpage = kmap_atomic(page);
527 memset(userpage + zero_offset, 0, zeros);
528 flush_dcache_page(page);
529 kunmap_atomic(userpage);
530 }
531 }
532
533 ret = bio_add_page(cb->orig_bio, page,
534 PAGE_CACHE_SIZE, 0);
535
536 if (ret == PAGE_CACHE_SIZE) {
537 nr_pages++;
538 page_cache_release(page);
539 } else {
540 unlock_extent(tree, last_offset, end);
541 unlock_page(page);
542 page_cache_release(page);
543 break;
544 }
545next:
546 last_offset += PAGE_CACHE_SIZE;
547 }
548 return 0;
549}
550
551
552
553
554
555
556
557
558
559
560
561
562
563int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
564 int mirror_num, unsigned long bio_flags)
565{
566 struct extent_io_tree *tree;
567 struct extent_map_tree *em_tree;
568 struct compressed_bio *cb;
569 struct btrfs_root *root = BTRFS_I(inode)->root;
570 unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
571 unsigned long compressed_len;
572 unsigned long nr_pages;
573 unsigned long pg_index;
574 struct page *page;
575 struct block_device *bdev;
576 struct bio *comp_bio;
577 u64 cur_disk_byte = (u64)bio->bi_iter.bi_sector << 9;
578 u64 em_len;
579 u64 em_start;
580 struct extent_map *em;
581 int ret = -ENOMEM;
582 int faili = 0;
583 u32 *sums;
584
585 tree = &BTRFS_I(inode)->io_tree;
586 em_tree = &BTRFS_I(inode)->extent_tree;
587
588
589 read_lock(&em_tree->lock);
590 em = lookup_extent_mapping(em_tree,
591 page_offset(bio->bi_io_vec->bv_page),
592 PAGE_CACHE_SIZE);
593 read_unlock(&em_tree->lock);
594 if (!em)
595 return -EIO;
596
597 compressed_len = em->block_len;
598 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
599 if (!cb)
600 goto out;
601
602 atomic_set(&cb->pending_bios, 0);
603 cb->errors = 0;
604 cb->inode = inode;
605 cb->mirror_num = mirror_num;
606 sums = &cb->sums;
607
608 cb->start = em->orig_start;
609 em_len = em->len;
610 em_start = em->start;
611
612 free_extent_map(em);
613 em = NULL;
614
615 cb->len = uncompressed_len;
616 cb->compressed_len = compressed_len;
617 cb->compress_type = extent_compress_type(bio_flags);
618 cb->orig_bio = bio;
619
620 nr_pages = DIV_ROUND_UP(compressed_len, PAGE_CACHE_SIZE);
621 cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *),
622 GFP_NOFS);
623 if (!cb->compressed_pages)
624 goto fail1;
625
626 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
627
628 for (pg_index = 0; pg_index < nr_pages; pg_index++) {
629 cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS |
630 __GFP_HIGHMEM);
631 if (!cb->compressed_pages[pg_index]) {
632 faili = pg_index - 1;
633 ret = -ENOMEM;
634 goto fail2;
635 }
636 }
637 faili = nr_pages - 1;
638 cb->nr_pages = nr_pages;
639
640
641
642
643 if (!(bio_flags & EXTENT_BIO_PARENT_LOCKED))
644 add_ra_bio_pages(inode, em_start + em_len, cb);
645
646
647 uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
648 cb->len = uncompressed_len;
649
650 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS);
651 if (!comp_bio)
652 goto fail2;
653 comp_bio->bi_private = cb;
654 comp_bio->bi_end_io = end_compressed_bio_read;
655 atomic_inc(&cb->pending_bios);
656
657 for (pg_index = 0; pg_index < nr_pages; pg_index++) {
658 page = cb->compressed_pages[pg_index];
659 page->mapping = inode->i_mapping;
660 page->index = em_start >> PAGE_CACHE_SHIFT;
661
662 if (comp_bio->bi_iter.bi_size)
663 ret = tree->ops->merge_bio_hook(READ, page, 0,
664 PAGE_CACHE_SIZE,
665 comp_bio, 0);
666 else
667 ret = 0;
668
669 page->mapping = NULL;
670 if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) <
671 PAGE_CACHE_SIZE) {
672 bio_get(comp_bio);
673
674 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio,
675 BTRFS_WQ_ENDIO_DATA);
676 BUG_ON(ret);
677
678
679
680
681
682
683
684 atomic_inc(&cb->pending_bios);
685
686 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
687 ret = btrfs_lookup_bio_sums(root, inode,
688 comp_bio, sums);
689 BUG_ON(ret);
690 }
691 sums += DIV_ROUND_UP(comp_bio->bi_iter.bi_size,
692 root->sectorsize);
693
694 ret = btrfs_map_bio(root, READ, comp_bio,
695 mirror_num, 0);
696 if (ret) {
697 bio->bi_error = ret;
698 bio_endio(comp_bio);
699 }
700
701 bio_put(comp_bio);
702
703 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
704 GFP_NOFS);
705 BUG_ON(!comp_bio);
706 comp_bio->bi_private = cb;
707 comp_bio->bi_end_io = end_compressed_bio_read;
708
709 bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0);
710 }
711 cur_disk_byte += PAGE_CACHE_SIZE;
712 }
713 bio_get(comp_bio);
714
715 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio,
716 BTRFS_WQ_ENDIO_DATA);
717 BUG_ON(ret);
718
719 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
720 ret = btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
721 BUG_ON(ret);
722 }
723
724 ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);
725 if (ret) {
726 bio->bi_error = ret;
727 bio_endio(comp_bio);
728 }
729
730 bio_put(comp_bio);
731 return 0;
732
733fail2:
734 while (faili >= 0) {
735 __free_page(cb->compressed_pages[faili]);
736 faili--;
737 }
738
739 kfree(cb->compressed_pages);
740fail1:
741 kfree(cb);
742out:
743 free_extent_map(em);
744 return ret;
745}
746
747static struct {
748 struct list_head idle_ws;
749 spinlock_t ws_lock;
750 int num_ws;
751 atomic_t alloc_ws;
752 wait_queue_head_t ws_wait;
753} btrfs_comp_ws[BTRFS_COMPRESS_TYPES];
754
755static const struct btrfs_compress_op * const btrfs_compress_op[] = {
756 &btrfs_zlib_compress,
757 &btrfs_lzo_compress,
758};
759
760void __init btrfs_init_compress(void)
761{
762 int i;
763
764 for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
765 INIT_LIST_HEAD(&btrfs_comp_ws[i].idle_ws);
766 spin_lock_init(&btrfs_comp_ws[i].ws_lock);
767 atomic_set(&btrfs_comp_ws[i].alloc_ws, 0);
768 init_waitqueue_head(&btrfs_comp_ws[i].ws_wait);
769 }
770}
771
772
773
774
775
776static struct list_head *find_workspace(int type)
777{
778 struct list_head *workspace;
779 int cpus = num_online_cpus();
780 int idx = type - 1;
781
782 struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws;
783 spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock;
784 atomic_t *alloc_ws = &btrfs_comp_ws[idx].alloc_ws;
785 wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait;
786 int *num_ws = &btrfs_comp_ws[idx].num_ws;
787again:
788 spin_lock(ws_lock);
789 if (!list_empty(idle_ws)) {
790 workspace = idle_ws->next;
791 list_del(workspace);
792 (*num_ws)--;
793 spin_unlock(ws_lock);
794 return workspace;
795
796 }
797 if (atomic_read(alloc_ws) > cpus) {
798 DEFINE_WAIT(wait);
799
800 spin_unlock(ws_lock);
801 prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE);
802 if (atomic_read(alloc_ws) > cpus && !*num_ws)
803 schedule();
804 finish_wait(ws_wait, &wait);
805 goto again;
806 }
807 atomic_inc(alloc_ws);
808 spin_unlock(ws_lock);
809
810 workspace = btrfs_compress_op[idx]->alloc_workspace();
811 if (IS_ERR(workspace)) {
812 atomic_dec(alloc_ws);
813 wake_up(ws_wait);
814 }
815 return workspace;
816}
817
818
819
820
821
822static void free_workspace(int type, struct list_head *workspace)
823{
824 int idx = type - 1;
825 struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws;
826 spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock;
827 atomic_t *alloc_ws = &btrfs_comp_ws[idx].alloc_ws;
828 wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait;
829 int *num_ws = &btrfs_comp_ws[idx].num_ws;
830
831 spin_lock(ws_lock);
832 if (*num_ws < num_online_cpus()) {
833 list_add(workspace, idle_ws);
834 (*num_ws)++;
835 spin_unlock(ws_lock);
836 goto wake;
837 }
838 spin_unlock(ws_lock);
839
840 btrfs_compress_op[idx]->free_workspace(workspace);
841 atomic_dec(alloc_ws);
842wake:
843
844
845
846 smp_mb();
847 if (waitqueue_active(ws_wait))
848 wake_up(ws_wait);
849}
850
851
852
853
854static void free_workspaces(void)
855{
856 struct list_head *workspace;
857 int i;
858
859 for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
860 while (!list_empty(&btrfs_comp_ws[i].idle_ws)) {
861 workspace = btrfs_comp_ws[i].idle_ws.next;
862 list_del(workspace);
863 btrfs_compress_op[i]->free_workspace(workspace);
864 atomic_dec(&btrfs_comp_ws[i].alloc_ws);
865 }
866 }
867}
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888int btrfs_compress_pages(int type, struct address_space *mapping,
889 u64 start, unsigned long len,
890 struct page **pages,
891 unsigned long nr_dest_pages,
892 unsigned long *out_pages,
893 unsigned long *total_in,
894 unsigned long *total_out,
895 unsigned long max_out)
896{
897 struct list_head *workspace;
898 int ret;
899
900 workspace = find_workspace(type);
901 if (IS_ERR(workspace))
902 return PTR_ERR(workspace);
903
904 ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping,
905 start, len, pages,
906 nr_dest_pages, out_pages,
907 total_in, total_out,
908 max_out);
909 free_workspace(type, workspace);
910 return ret;
911}
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929static int btrfs_decompress_biovec(int type, struct page **pages_in,
930 u64 disk_start, struct bio_vec *bvec,
931 int vcnt, size_t srclen)
932{
933 struct list_head *workspace;
934 int ret;
935
936 workspace = find_workspace(type);
937 if (IS_ERR(workspace))
938 return PTR_ERR(workspace);
939
940 ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in,
941 disk_start,
942 bvec, vcnt, srclen);
943 free_workspace(type, workspace);
944 return ret;
945}
946
947
948
949
950
951
952int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
953 unsigned long start_byte, size_t srclen, size_t destlen)
954{
955 struct list_head *workspace;
956 int ret;
957
958 workspace = find_workspace(type);
959 if (IS_ERR(workspace))
960 return PTR_ERR(workspace);
961
962 ret = btrfs_compress_op[type-1]->decompress(workspace, data_in,
963 dest_page, start_byte,
964 srclen, destlen);
965
966 free_workspace(type, workspace);
967 return ret;
968}
969
970void btrfs_exit_compress(void)
971{
972 free_workspaces();
973}
974
975
976
977
978
979
980
981
982int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
983 unsigned long total_out, u64 disk_start,
984 struct bio_vec *bvec, int vcnt,
985 unsigned long *pg_index,
986 unsigned long *pg_offset)
987{
988 unsigned long buf_offset;
989 unsigned long current_buf_start;
990 unsigned long start_byte;
991 unsigned long working_bytes = total_out - buf_start;
992 unsigned long bytes;
993 char *kaddr;
994 struct page *page_out = bvec[*pg_index].bv_page;
995
996
997
998
999
1000 start_byte = page_offset(page_out) - disk_start;
1001
1002
1003 if (total_out <= start_byte)
1004 return 1;
1005
1006
1007
1008
1009
1010 if (total_out > start_byte && buf_start < start_byte) {
1011 buf_offset = start_byte - buf_start;
1012 working_bytes -= buf_offset;
1013 } else {
1014 buf_offset = 0;
1015 }
1016 current_buf_start = buf_start;
1017
1018
1019 while (working_bytes > 0) {
1020 bytes = min(PAGE_CACHE_SIZE - *pg_offset,
1021 PAGE_CACHE_SIZE - buf_offset);
1022 bytes = min(bytes, working_bytes);
1023 kaddr = kmap_atomic(page_out);
1024 memcpy(kaddr + *pg_offset, buf + buf_offset, bytes);
1025 kunmap_atomic(kaddr);
1026 flush_dcache_page(page_out);
1027
1028 *pg_offset += bytes;
1029 buf_offset += bytes;
1030 working_bytes -= bytes;
1031 current_buf_start += bytes;
1032
1033
1034 if (*pg_offset == PAGE_CACHE_SIZE) {
1035 (*pg_index)++;
1036 if (*pg_index >= vcnt)
1037 return 0;
1038
1039 page_out = bvec[*pg_index].bv_page;
1040 *pg_offset = 0;
1041 start_byte = page_offset(page_out) - disk_start;
1042
1043
1044
1045
1046
1047 if (total_out <= start_byte)
1048 return 1;
1049
1050
1051
1052
1053
1054
1055 if (total_out > start_byte &&
1056 current_buf_start < start_byte) {
1057 buf_offset = start_byte - buf_start;
1058 working_bytes = total_out - start_byte;
1059 current_buf_start = buf_start + buf_offset;
1060 }
1061 }
1062 }
1063
1064 return 1;
1065}
1066
1067
1068
1069
1070
1071
1072
1073
1074void btrfs_clear_biovec_end(struct bio_vec *bvec, int vcnt,
1075 unsigned long pg_index,
1076 unsigned long pg_offset)
1077{
1078 while (pg_index < vcnt) {
1079 struct page *page = bvec[pg_index].bv_page;
1080 unsigned long off = bvec[pg_index].bv_offset;
1081 unsigned long len = bvec[pg_index].bv_len;
1082
1083 if (pg_offset < off)
1084 pg_offset = off;
1085 if (pg_offset < off + len) {
1086 unsigned long bytes = off + len - pg_offset;
1087 char *kaddr;
1088
1089 kaddr = kmap_atomic(page);
1090 memset(kaddr + pg_offset, 0, bytes);
1091 kunmap_atomic(kaddr);
1092 }
1093 pg_index++;
1094 pg_offset = 0;
1095 }
1096}
1097