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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 "compat.h"
36#include "ctree.h"
37#include "disk-io.h"
38#include "transaction.h"
39#include "btrfs_inode.h"
40#include "volumes.h"
41#include "ordered-data.h"
42#include "compression.h"
43#include "extent_io.h"
44#include "extent_map.h"
45
46struct compressed_bio {
47
48 atomic_t pending_bios;
49
50
51 struct page **compressed_pages;
52
53
54 struct inode *inode;
55
56
57 u64 start;
58
59
60 unsigned long len;
61
62
63 unsigned long compressed_len;
64
65
66 int compress_type;
67
68
69 unsigned long nr_pages;
70
71
72 int errors;
73 int mirror_num;
74
75
76 struct bio *orig_bio;
77
78
79
80
81
82 u32 sums;
83};
84
85static inline int compressed_bio_size(struct btrfs_root *root,
86 unsigned long disk_size)
87{
88 u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy);
89 return sizeof(struct compressed_bio) +
90 ((disk_size + root->sectorsize - 1) / root->sectorsize) *
91 csum_size;
92}
93
94static struct bio *compressed_bio_alloc(struct block_device *bdev,
95 u64 first_byte, gfp_t gfp_flags)
96{
97 int nr_vecs;
98
99 nr_vecs = bio_get_nr_vecs(bdev);
100 return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, 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 btrfs_root *root = BTRFS_I(inode)->root;
109 struct page *page;
110 unsigned long i;
111 char *kaddr;
112 u32 csum;
113 u32 *cb_sum = &cb->sums;
114
115 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
116 return 0;
117
118 for (i = 0; i < cb->nr_pages; i++) {
119 page = cb->compressed_pages[i];
120 csum = ~(u32)0;
121
122 kaddr = kmap_atomic(page, KM_USER0);
123 csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE);
124 btrfs_csum_final(csum, (char *)&csum);
125 kunmap_atomic(kaddr, KM_USER0);
126
127 if (csum != *cb_sum) {
128 printk(KERN_INFO "btrfs csum failed ino %llu "
129 "extent %llu csum %u "
130 "wanted %u mirror %d\n",
131 (unsigned long long)btrfs_ino(inode),
132 (unsigned long long)disk_start,
133 csum, *cb_sum, cb->mirror_num);
134 ret = -EIO;
135 goto fail;
136 }
137 cb_sum++;
138
139 }
140 ret = 0;
141fail:
142 return ret;
143}
144
145
146
147
148
149
150
151
152
153
154
155static void end_compressed_bio_read(struct bio *bio, int err)
156{
157 struct compressed_bio *cb = bio->bi_private;
158 struct inode *inode;
159 struct page *page;
160 unsigned long index;
161 int ret;
162
163 if (err)
164 cb->errors = 1;
165
166
167
168
169 if (!atomic_dec_and_test(&cb->pending_bios))
170 goto out;
171
172 inode = cb->inode;
173 ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9);
174 if (ret)
175 goto csum_failed;
176
177
178
179
180 ret = btrfs_decompress_biovec(cb->compress_type,
181 cb->compressed_pages,
182 cb->start,
183 cb->orig_bio->bi_io_vec,
184 cb->orig_bio->bi_vcnt,
185 cb->compressed_len);
186csum_failed:
187 if (ret)
188 cb->errors = 1;
189
190
191 index = 0;
192 for (index = 0; index < cb->nr_pages; index++) {
193 page = cb->compressed_pages[index];
194 page->mapping = NULL;
195 page_cache_release(page);
196 }
197
198
199 if (cb->errors) {
200 bio_io_error(cb->orig_bio);
201 } else {
202 int bio_index = 0;
203 struct bio_vec *bvec = cb->orig_bio->bi_io_vec;
204
205
206
207
208
209 while (bio_index < cb->orig_bio->bi_vcnt) {
210 SetPageChecked(bvec->bv_page);
211 bvec++;
212 bio_index++;
213 }
214 bio_endio(cb->orig_bio, 0);
215 }
216
217
218 kfree(cb->compressed_pages);
219 kfree(cb);
220out:
221 bio_put(bio);
222}
223
224
225
226
227
228static noinline int end_compressed_writeback(struct inode *inode, u64 start,
229 unsigned long ram_size)
230{
231 unsigned long index = start >> PAGE_CACHE_SHIFT;
232 unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT;
233 struct page *pages[16];
234 unsigned long nr_pages = end_index - index + 1;
235 int i;
236 int ret;
237
238 while (nr_pages > 0) {
239 ret = find_get_pages_contig(inode->i_mapping, index,
240 min_t(unsigned long,
241 nr_pages, ARRAY_SIZE(pages)), pages);
242 if (ret == 0) {
243 nr_pages -= 1;
244 index += 1;
245 continue;
246 }
247 for (i = 0; i < ret; i++) {
248 end_page_writeback(pages[i]);
249 page_cache_release(pages[i]);
250 }
251 nr_pages -= ret;
252 index += ret;
253 }
254
255 return 0;
256}
257
258
259
260
261
262
263
264
265
266static void end_compressed_bio_write(struct bio *bio, int err)
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 (err)
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, 1);
293 cb->compressed_pages[0]->mapping = NULL;
294
295 end_compressed_writeback(inode, cb->start, cb->len);
296
297
298
299
300
301
302 index = 0;
303 for (index = 0; index < cb->nr_pages; index++) {
304 page = cb->compressed_pages[index];
305 page->mapping = NULL;
306 page_cache_release(page);
307 }
308
309
310 kfree(cb->compressed_pages);
311 kfree(cb);
312out:
313 bio_put(bio);
314}
315
316
317
318
319
320
321
322
323
324
325int btrfs_submit_compressed_write(struct inode *inode, u64 start,
326 unsigned long len, u64 disk_start,
327 unsigned long compressed_len,
328 struct page **compressed_pages,
329 unsigned long nr_pages)
330{
331 struct bio *bio = NULL;
332 struct btrfs_root *root = BTRFS_I(inode)->root;
333 struct compressed_bio *cb;
334 unsigned long bytes_left;
335 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
336 int pg_index = 0;
337 struct page *page;
338 u64 first_byte = disk_start;
339 struct block_device *bdev;
340 int ret;
341 int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
342
343 WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
344 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
345 if (!cb)
346 return -ENOMEM;
347 atomic_set(&cb->pending_bios, 0);
348 cb->errors = 0;
349 cb->inode = inode;
350 cb->start = start;
351 cb->len = len;
352 cb->mirror_num = 0;
353 cb->compressed_pages = compressed_pages;
354 cb->compressed_len = compressed_len;
355 cb->orig_bio = NULL;
356 cb->nr_pages = nr_pages;
357
358 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
359
360 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
361 if(!bio) {
362 kfree(cb);
363 return -ENOMEM;
364 }
365 bio->bi_private = cb;
366 bio->bi_end_io = end_compressed_bio_write;
367 atomic_inc(&cb->pending_bios);
368
369
370 bytes_left = compressed_len;
371 for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) {
372 page = compressed_pages[pg_index];
373 page->mapping = inode->i_mapping;
374 if (bio->bi_size)
375 ret = io_tree->ops->merge_bio_hook(page, 0,
376 PAGE_CACHE_SIZE,
377 bio, 0);
378 else
379 ret = 0;
380
381 page->mapping = NULL;
382 if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) <
383 PAGE_CACHE_SIZE) {
384 bio_get(bio);
385
386
387
388
389
390
391
392 atomic_inc(&cb->pending_bios);
393 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
394 BUG_ON(ret);
395
396 if (!skip_sum) {
397 ret = btrfs_csum_one_bio(root, inode, bio,
398 start, 1);
399 BUG_ON(ret);
400 }
401
402 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
403 BUG_ON(ret);
404
405 bio_put(bio);
406
407 bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
408 bio->bi_private = cb;
409 bio->bi_end_io = end_compressed_bio_write;
410 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
411 }
412 if (bytes_left < PAGE_CACHE_SIZE) {
413 printk("bytes left %lu compress len %lu nr %lu\n",
414 bytes_left, cb->compressed_len, cb->nr_pages);
415 }
416 bytes_left -= PAGE_CACHE_SIZE;
417 first_byte += PAGE_CACHE_SIZE;
418 cond_resched();
419 }
420 bio_get(bio);
421
422 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
423 BUG_ON(ret);
424
425 if (!skip_sum) {
426 ret = btrfs_csum_one_bio(root, inode, bio, start, 1);
427 BUG_ON(ret);
428 }
429
430 ret = btrfs_map_bio(root, WRITE, bio, 0, 1);
431 BUG_ON(ret);
432
433 bio_put(bio);
434 return 0;
435}
436
437static noinline int add_ra_bio_pages(struct inode *inode,
438 u64 compressed_end,
439 struct compressed_bio *cb)
440{
441 unsigned long end_index;
442 unsigned long pg_index;
443 u64 last_offset;
444 u64 isize = i_size_read(inode);
445 int ret;
446 struct page *page;
447 unsigned long nr_pages = 0;
448 struct extent_map *em;
449 struct address_space *mapping = inode->i_mapping;
450 struct extent_map_tree *em_tree;
451 struct extent_io_tree *tree;
452 u64 end;
453 int misses = 0;
454
455 page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page;
456 last_offset = (page_offset(page) + PAGE_CACHE_SIZE);
457 em_tree = &BTRFS_I(inode)->extent_tree;
458 tree = &BTRFS_I(inode)->io_tree;
459
460 if (isize == 0)
461 return 0;
462
463 end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
464
465 while (last_offset < compressed_end) {
466 pg_index = last_offset >> PAGE_CACHE_SHIFT;
467
468 if (pg_index > end_index)
469 break;
470
471 rcu_read_lock();
472 page = radix_tree_lookup(&mapping->page_tree, pg_index);
473 rcu_read_unlock();
474 if (page) {
475 misses++;
476 if (misses > 4)
477 break;
478 goto next;
479 }
480
481 page = __page_cache_alloc(mapping_gfp_mask(mapping) &
482 ~__GFP_FS);
483 if (!page)
484 break;
485
486 if (add_to_page_cache_lru(page, mapping, pg_index,
487 GFP_NOFS)) {
488 page_cache_release(page);
489 goto next;
490 }
491
492 end = last_offset + PAGE_CACHE_SIZE - 1;
493
494
495
496
497
498 set_page_extent_mapped(page);
499 lock_extent(tree, last_offset, end, GFP_NOFS);
500 read_lock(&em_tree->lock);
501 em = lookup_extent_mapping(em_tree, last_offset,
502 PAGE_CACHE_SIZE);
503 read_unlock(&em_tree->lock);
504
505 if (!em || last_offset < em->start ||
506 (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) ||
507 (em->block_start >> 9) != cb->orig_bio->bi_sector) {
508 free_extent_map(em);
509 unlock_extent(tree, last_offset, end, GFP_NOFS);
510 unlock_page(page);
511 page_cache_release(page);
512 break;
513 }
514 free_extent_map(em);
515
516 if (page->index == end_index) {
517 char *userpage;
518 size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1);
519
520 if (zero_offset) {
521 int zeros;
522 zeros = PAGE_CACHE_SIZE - zero_offset;
523 userpage = kmap_atomic(page, KM_USER0);
524 memset(userpage + zero_offset, 0, zeros);
525 flush_dcache_page(page);
526 kunmap_atomic(userpage, KM_USER0);
527 }
528 }
529
530 ret = bio_add_page(cb->orig_bio, page,
531 PAGE_CACHE_SIZE, 0);
532
533 if (ret == PAGE_CACHE_SIZE) {
534 nr_pages++;
535 page_cache_release(page);
536 } else {
537 unlock_extent(tree, last_offset, end, GFP_NOFS);
538 unlock_page(page);
539 page_cache_release(page);
540 break;
541 }
542next:
543 last_offset += PAGE_CACHE_SIZE;
544 }
545 return 0;
546}
547
548
549
550
551
552
553
554
555
556
557
558
559
560int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
561 int mirror_num, unsigned long bio_flags)
562{
563 struct extent_io_tree *tree;
564 struct extent_map_tree *em_tree;
565 struct compressed_bio *cb;
566 struct btrfs_root *root = BTRFS_I(inode)->root;
567 unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
568 unsigned long compressed_len;
569 unsigned long nr_pages;
570 unsigned long pg_index;
571 struct page *page;
572 struct block_device *bdev;
573 struct bio *comp_bio;
574 u64 cur_disk_byte = (u64)bio->bi_sector << 9;
575 u64 em_len;
576 u64 em_start;
577 struct extent_map *em;
578 int ret = -ENOMEM;
579 u32 *sums;
580
581 tree = &BTRFS_I(inode)->io_tree;
582 em_tree = &BTRFS_I(inode)->extent_tree;
583
584
585 read_lock(&em_tree->lock);
586 em = lookup_extent_mapping(em_tree,
587 page_offset(bio->bi_io_vec->bv_page),
588 PAGE_CACHE_SIZE);
589 read_unlock(&em_tree->lock);
590
591 compressed_len = em->block_len;
592 cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
593 if (!cb)
594 goto out;
595
596 atomic_set(&cb->pending_bios, 0);
597 cb->errors = 0;
598 cb->inode = inode;
599 cb->mirror_num = mirror_num;
600 sums = &cb->sums;
601
602 cb->start = em->orig_start;
603 em_len = em->len;
604 em_start = em->start;
605
606 free_extent_map(em);
607 em = NULL;
608
609 cb->len = uncompressed_len;
610 cb->compressed_len = compressed_len;
611 cb->compress_type = extent_compress_type(bio_flags);
612 cb->orig_bio = bio;
613
614 nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
615 PAGE_CACHE_SIZE;
616 cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages,
617 GFP_NOFS);
618 if (!cb->compressed_pages)
619 goto fail1;
620
621 bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
622
623 for (pg_index = 0; pg_index < nr_pages; pg_index++) {
624 cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS |
625 __GFP_HIGHMEM);
626 if (!cb->compressed_pages[pg_index])
627 goto fail2;
628 }
629 cb->nr_pages = nr_pages;
630
631 add_ra_bio_pages(inode, em_start + em_len, cb);
632
633
634 uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE;
635 cb->len = uncompressed_len;
636
637 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS);
638 if (!comp_bio)
639 goto fail2;
640 comp_bio->bi_private = cb;
641 comp_bio->bi_end_io = end_compressed_bio_read;
642 atomic_inc(&cb->pending_bios);
643
644 for (pg_index = 0; pg_index < nr_pages; pg_index++) {
645 page = cb->compressed_pages[pg_index];
646 page->mapping = inode->i_mapping;
647 page->index = em_start >> PAGE_CACHE_SHIFT;
648
649 if (comp_bio->bi_size)
650 ret = tree->ops->merge_bio_hook(page, 0,
651 PAGE_CACHE_SIZE,
652 comp_bio, 0);
653 else
654 ret = 0;
655
656 page->mapping = NULL;
657 if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) <
658 PAGE_CACHE_SIZE) {
659 bio_get(comp_bio);
660
661 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
662 BUG_ON(ret);
663
664
665
666
667
668
669
670 atomic_inc(&cb->pending_bios);
671
672 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
673 ret = btrfs_lookup_bio_sums(root, inode,
674 comp_bio, sums);
675 BUG_ON(ret);
676 }
677 sums += (comp_bio->bi_size + root->sectorsize - 1) /
678 root->sectorsize;
679
680 ret = btrfs_map_bio(root, READ, comp_bio,
681 mirror_num, 0);
682 BUG_ON(ret);
683
684 bio_put(comp_bio);
685
686 comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
687 GFP_NOFS);
688 comp_bio->bi_private = cb;
689 comp_bio->bi_end_io = end_compressed_bio_read;
690
691 bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0);
692 }
693 cur_disk_byte += PAGE_CACHE_SIZE;
694 }
695 bio_get(comp_bio);
696
697 ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0);
698 BUG_ON(ret);
699
700 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
701 ret = btrfs_lookup_bio_sums(root, inode, comp_bio, sums);
702 BUG_ON(ret);
703 }
704
705 ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0);
706 BUG_ON(ret);
707
708 bio_put(comp_bio);
709 return 0;
710
711fail2:
712 for (pg_index = 0; pg_index < nr_pages; pg_index++)
713 free_page((unsigned long)cb->compressed_pages[pg_index]);
714
715 kfree(cb->compressed_pages);
716fail1:
717 kfree(cb);
718out:
719 free_extent_map(em);
720 return ret;
721}
722
723static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES];
724static spinlock_t comp_workspace_lock[BTRFS_COMPRESS_TYPES];
725static int comp_num_workspace[BTRFS_COMPRESS_TYPES];
726static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES];
727static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES];
728
729struct btrfs_compress_op *btrfs_compress_op[] = {
730 &btrfs_zlib_compress,
731 &btrfs_lzo_compress,
732};
733
734int __init btrfs_init_compress(void)
735{
736 int i;
737
738 for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
739 INIT_LIST_HEAD(&comp_idle_workspace[i]);
740 spin_lock_init(&comp_workspace_lock[i]);
741 atomic_set(&comp_alloc_workspace[i], 0);
742 init_waitqueue_head(&comp_workspace_wait[i]);
743 }
744 return 0;
745}
746
747
748
749
750
751static struct list_head *find_workspace(int type)
752{
753 struct list_head *workspace;
754 int cpus = num_online_cpus();
755 int idx = type - 1;
756
757 struct list_head *idle_workspace = &comp_idle_workspace[idx];
758 spinlock_t *workspace_lock = &comp_workspace_lock[idx];
759 atomic_t *alloc_workspace = &comp_alloc_workspace[idx];
760 wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx];
761 int *num_workspace = &comp_num_workspace[idx];
762again:
763 spin_lock(workspace_lock);
764 if (!list_empty(idle_workspace)) {
765 workspace = idle_workspace->next;
766 list_del(workspace);
767 (*num_workspace)--;
768 spin_unlock(workspace_lock);
769 return workspace;
770
771 }
772 if (atomic_read(alloc_workspace) > cpus) {
773 DEFINE_WAIT(wait);
774
775 spin_unlock(workspace_lock);
776 prepare_to_wait(workspace_wait, &wait, TASK_UNINTERRUPTIBLE);
777 if (atomic_read(alloc_workspace) > cpus && !*num_workspace)
778 schedule();
779 finish_wait(workspace_wait, &wait);
780 goto again;
781 }
782 atomic_inc(alloc_workspace);
783 spin_unlock(workspace_lock);
784
785 workspace = btrfs_compress_op[idx]->alloc_workspace();
786 if (IS_ERR(workspace)) {
787 atomic_dec(alloc_workspace);
788 wake_up(workspace_wait);
789 }
790 return workspace;
791}
792
793
794
795
796
797static void free_workspace(int type, struct list_head *workspace)
798{
799 int idx = type - 1;
800 struct list_head *idle_workspace = &comp_idle_workspace[idx];
801 spinlock_t *workspace_lock = &comp_workspace_lock[idx];
802 atomic_t *alloc_workspace = &comp_alloc_workspace[idx];
803 wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx];
804 int *num_workspace = &comp_num_workspace[idx];
805
806 spin_lock(workspace_lock);
807 if (*num_workspace < num_online_cpus()) {
808 list_add_tail(workspace, idle_workspace);
809 (*num_workspace)++;
810 spin_unlock(workspace_lock);
811 goto wake;
812 }
813 spin_unlock(workspace_lock);
814
815 btrfs_compress_op[idx]->free_workspace(workspace);
816 atomic_dec(alloc_workspace);
817wake:
818 if (waitqueue_active(workspace_wait))
819 wake_up(workspace_wait);
820}
821
822
823
824
825static void free_workspaces(void)
826{
827 struct list_head *workspace;
828 int i;
829
830 for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) {
831 while (!list_empty(&comp_idle_workspace[i])) {
832 workspace = comp_idle_workspace[i].next;
833 list_del(workspace);
834 btrfs_compress_op[i]->free_workspace(workspace);
835 atomic_dec(&comp_alloc_workspace[i]);
836 }
837 }
838}
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859int btrfs_compress_pages(int type, struct address_space *mapping,
860 u64 start, unsigned long len,
861 struct page **pages,
862 unsigned long nr_dest_pages,
863 unsigned long *out_pages,
864 unsigned long *total_in,
865 unsigned long *total_out,
866 unsigned long max_out)
867{
868 struct list_head *workspace;
869 int ret;
870
871 workspace = find_workspace(type);
872 if (IS_ERR(workspace))
873 return -1;
874
875 ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping,
876 start, len, pages,
877 nr_dest_pages, out_pages,
878 total_in, total_out,
879 max_out);
880 free_workspace(type, workspace);
881 return ret;
882}
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900int btrfs_decompress_biovec(int type, struct page **pages_in, u64 disk_start,
901 struct bio_vec *bvec, int vcnt, size_t srclen)
902{
903 struct list_head *workspace;
904 int ret;
905
906 workspace = find_workspace(type);
907 if (IS_ERR(workspace))
908 return -ENOMEM;
909
910 ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in,
911 disk_start,
912 bvec, vcnt, srclen);
913 free_workspace(type, workspace);
914 return ret;
915}
916
917
918
919
920
921
922int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page,
923 unsigned long start_byte, size_t srclen, size_t destlen)
924{
925 struct list_head *workspace;
926 int ret;
927
928 workspace = find_workspace(type);
929 if (IS_ERR(workspace))
930 return -ENOMEM;
931
932 ret = btrfs_compress_op[type-1]->decompress(workspace, data_in,
933 dest_page, start_byte,
934 srclen, destlen);
935
936 free_workspace(type, workspace);
937 return ret;
938}
939
940void btrfs_exit_compress(void)
941{
942 free_workspaces();
943}
944
945
946
947
948
949
950
951
952int btrfs_decompress_buf2page(char *buf, unsigned long buf_start,
953 unsigned long total_out, u64 disk_start,
954 struct bio_vec *bvec, int vcnt,
955 unsigned long *pg_index,
956 unsigned long *pg_offset)
957{
958 unsigned long buf_offset;
959 unsigned long current_buf_start;
960 unsigned long start_byte;
961 unsigned long working_bytes = total_out - buf_start;
962 unsigned long bytes;
963 char *kaddr;
964 struct page *page_out = bvec[*pg_index].bv_page;
965
966
967
968
969
970 start_byte = page_offset(page_out) - disk_start;
971
972
973 if (total_out <= start_byte)
974 return 1;
975
976
977
978
979
980 if (total_out > start_byte && buf_start < start_byte) {
981 buf_offset = start_byte - buf_start;
982 working_bytes -= buf_offset;
983 } else {
984 buf_offset = 0;
985 }
986 current_buf_start = buf_start;
987
988
989 while (working_bytes > 0) {
990 bytes = min(PAGE_CACHE_SIZE - *pg_offset,
991 PAGE_CACHE_SIZE - buf_offset);
992 bytes = min(bytes, working_bytes);
993 kaddr = kmap_atomic(page_out, KM_USER0);
994 memcpy(kaddr + *pg_offset, buf + buf_offset, bytes);
995 kunmap_atomic(kaddr, KM_USER0);
996 flush_dcache_page(page_out);
997
998 *pg_offset += bytes;
999 buf_offset += bytes;
1000 working_bytes -= bytes;
1001 current_buf_start += bytes;
1002
1003
1004 if (*pg_offset == PAGE_CACHE_SIZE) {
1005 (*pg_index)++;
1006 if (*pg_index >= vcnt)
1007 return 0;
1008
1009 page_out = bvec[*pg_index].bv_page;
1010 *pg_offset = 0;
1011 start_byte = page_offset(page_out) - disk_start;
1012
1013
1014
1015
1016
1017 if (total_out <= start_byte)
1018 return 1;
1019
1020
1021
1022
1023
1024
1025 if (total_out > start_byte &&
1026 current_buf_start < start_byte) {
1027 buf_offset = start_byte - buf_start;
1028 working_bytes = total_out - start_byte;
1029 current_buf_start = buf_start + buf_offset;
1030 }
1031 }
1032 }
1033
1034 return 1;
1035}
1036