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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/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 | ||
46 | struct compressed_bio { | |
47 | /* number of bios pending for this compressed extent */ | |
48 | atomic_t pending_bios; | |
49 | ||
50 | /* the pages with the compressed data on them */ | |
51 | struct page **compressed_pages; | |
52 | ||
53 | /* inode that owns this data */ | |
54 | struct inode *inode; | |
55 | ||
56 | /* starting offset in the inode for our pages */ | |
57 | u64 start; | |
58 | ||
59 | /* number of bytes in the inode we're working on */ | |
60 | unsigned long len; | |
61 | ||
62 | /* number of bytes on disk */ | |
63 | unsigned long compressed_len; | |
64 | ||
65 | /* the compression algorithm for this bio */ | |
66 | int compress_type; | |
67 | ||
68 | /* number of compressed pages in the array */ | |
69 | unsigned long nr_pages; | |
70 | ||
71 | /* IO errors */ | |
72 | int errors; | |
73 | int mirror_num; | |
74 | ||
75 | /* for reads, this is the bio we are copying the data into */ | |
76 | struct bio *orig_bio; | |
77 | ||
78 | /* | |
79 | * the start of a variable length array of checksums only | |
80 | * used by reads | |
81 | */ | |
82 | u32 sums; | |
83 | }; | |
84 | ||
85 | static int btrfs_decompress_biovec(int type, struct page **pages_in, | |
86 | u64 disk_start, struct bio_vec *bvec, | |
87 | int vcnt, size_t srclen); | |
88 | ||
89 | static inline int compressed_bio_size(struct btrfs_root *root, | |
90 | unsigned long disk_size) | |
91 | { | |
92 | u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); | |
93 | ||
94 | return sizeof(struct compressed_bio) + | |
95 | ((disk_size + root->sectorsize - 1) / root->sectorsize) * | |
96 | csum_size; | |
97 | } | |
98 | ||
99 | static struct bio *compressed_bio_alloc(struct block_device *bdev, | |
100 | u64 first_byte, gfp_t gfp_flags) | |
101 | { | |
102 | int nr_vecs; | |
103 | ||
104 | nr_vecs = bio_get_nr_vecs(bdev); | |
105 | return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, gfp_flags); | |
106 | } | |
107 | ||
108 | static int check_compressed_csum(struct inode *inode, | |
109 | struct compressed_bio *cb, | |
110 | u64 disk_start) | |
111 | { | |
112 | int ret; | |
113 | struct page *page; | |
114 | unsigned long i; | |
115 | char *kaddr; | |
116 | u32 csum; | |
117 | u32 *cb_sum = &cb->sums; | |
118 | ||
119 | if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) | |
120 | return 0; | |
121 | ||
122 | for (i = 0; i < cb->nr_pages; i++) { | |
123 | page = cb->compressed_pages[i]; | |
124 | csum = ~(u32)0; | |
125 | ||
126 | kaddr = kmap_atomic(page); | |
127 | csum = btrfs_csum_data(kaddr, csum, PAGE_CACHE_SIZE); | |
128 | btrfs_csum_final(csum, (char *)&csum); | |
129 | kunmap_atomic(kaddr); | |
130 | ||
131 | if (csum != *cb_sum) { | |
132 | printk(KERN_INFO "btrfs csum failed ino %llu " | |
133 | "extent %llu csum %u " | |
134 | "wanted %u mirror %d\n", | |
135 | btrfs_ino(inode), disk_start, csum, *cb_sum, | |
136 | cb->mirror_num); | |
137 | ret = -EIO; | |
138 | goto fail; | |
139 | } | |
140 | cb_sum++; | |
141 | ||
142 | } | |
143 | ret = 0; | |
144 | fail: | |
145 | return ret; | |
146 | } | |
147 | ||
148 | /* when we finish reading compressed pages from the disk, we | |
149 | * decompress them and then run the bio end_io routines on the | |
150 | * decompressed pages (in the inode address space). | |
151 | * | |
152 | * This allows the checksumming and other IO error handling routines | |
153 | * to work normally | |
154 | * | |
155 | * The compressed pages are freed here, and it must be run | |
156 | * in process context | |
157 | */ | |
158 | static void end_compressed_bio_read(struct bio *bio, int err) | |
159 | { | |
160 | struct compressed_bio *cb = bio->bi_private; | |
161 | struct inode *inode; | |
162 | struct page *page; | |
163 | unsigned long index; | |
164 | int ret; | |
165 | ||
166 | if (err) | |
167 | cb->errors = 1; | |
168 | ||
169 | /* if there are more bios still pending for this compressed | |
170 | * extent, just exit | |
171 | */ | |
172 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
173 | goto out; | |
174 | ||
175 | inode = cb->inode; | |
176 | ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); | |
177 | if (ret) | |
178 | goto csum_failed; | |
179 | ||
180 | /* ok, we're the last bio for this extent, lets start | |
181 | * the decompression. | |
182 | */ | |
183 | ret = btrfs_decompress_biovec(cb->compress_type, | |
184 | cb->compressed_pages, | |
185 | cb->start, | |
186 | cb->orig_bio->bi_io_vec, | |
187 | cb->orig_bio->bi_vcnt, | |
188 | cb->compressed_len); | |
189 | csum_failed: | |
190 | if (ret) | |
191 | cb->errors = 1; | |
192 | ||
193 | /* release the compressed pages */ | |
194 | index = 0; | |
195 | for (index = 0; index < cb->nr_pages; index++) { | |
196 | page = cb->compressed_pages[index]; | |
197 | page->mapping = NULL; | |
198 | page_cache_release(page); | |
199 | } | |
200 | ||
201 | /* do io completion on the original bio */ | |
202 | if (cb->errors) { | |
203 | bio_io_error(cb->orig_bio); | |
204 | } else { | |
205 | int bio_index = 0; | |
206 | struct bio_vec *bvec = cb->orig_bio->bi_io_vec; | |
207 | ||
208 | /* | |
209 | * we have verified the checksum already, set page | |
210 | * checked so the end_io handlers know about it | |
211 | */ | |
212 | while (bio_index < cb->orig_bio->bi_vcnt) { | |
213 | SetPageChecked(bvec->bv_page); | |
214 | bvec++; | |
215 | bio_index++; | |
216 | } | |
217 | bio_endio(cb->orig_bio, 0); | |
218 | } | |
219 | ||
220 | /* finally free the cb struct */ | |
221 | kfree(cb->compressed_pages); | |
222 | kfree(cb); | |
223 | out: | |
224 | bio_put(bio); | |
225 | } | |
226 | ||
227 | /* | |
228 | * Clear the writeback bits on all of the file | |
229 | * pages for a compressed write | |
230 | */ | |
231 | static noinline void end_compressed_writeback(struct inode *inode, u64 start, | |
232 | unsigned long ram_size) | |
233 | { | |
234 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
235 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
236 | struct page *pages[16]; | |
237 | unsigned long nr_pages = end_index - index + 1; | |
238 | int i; | |
239 | int ret; | |
240 | ||
241 | while (nr_pages > 0) { | |
242 | ret = find_get_pages_contig(inode->i_mapping, index, | |
243 | min_t(unsigned long, | |
244 | nr_pages, ARRAY_SIZE(pages)), pages); | |
245 | if (ret == 0) { | |
246 | nr_pages -= 1; | |
247 | index += 1; | |
248 | continue; | |
249 | } | |
250 | for (i = 0; i < ret; i++) { | |
251 | end_page_writeback(pages[i]); | |
252 | page_cache_release(pages[i]); | |
253 | } | |
254 | nr_pages -= ret; | |
255 | index += ret; | |
256 | } | |
257 | /* the inode may be gone now */ | |
258 | } | |
259 | ||
260 | /* | |
261 | * do the cleanup once all the compressed pages hit the disk. | |
262 | * This will clear writeback on the file pages and free the compressed | |
263 | * pages. | |
264 | * | |
265 | * This also calls the writeback end hooks for the file pages so that | |
266 | * metadata and checksums can be updated in the file. | |
267 | */ | |
268 | static void end_compressed_bio_write(struct bio *bio, int err) | |
269 | { | |
270 | struct extent_io_tree *tree; | |
271 | struct compressed_bio *cb = bio->bi_private; | |
272 | struct inode *inode; | |
273 | struct page *page; | |
274 | unsigned long index; | |
275 | ||
276 | if (err) | |
277 | cb->errors = 1; | |
278 | ||
279 | /* if there are more bios still pending for this compressed | |
280 | * extent, just exit | |
281 | */ | |
282 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
283 | goto out; | |
284 | ||
285 | /* ok, we're the last bio for this extent, step one is to | |
286 | * call back into the FS and do all the end_io operations | |
287 | */ | |
288 | inode = cb->inode; | |
289 | tree = &BTRFS_I(inode)->io_tree; | |
290 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; | |
291 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], | |
292 | cb->start, | |
293 | cb->start + cb->len - 1, | |
294 | NULL, 1); | |
295 | cb->compressed_pages[0]->mapping = NULL; | |
296 | ||
297 | end_compressed_writeback(inode, cb->start, cb->len); | |
298 | /* note, our inode could be gone now */ | |
299 | ||
300 | /* | |
301 | * release the compressed pages, these came from alloc_page and | |
302 | * are not attached to the inode at all | |
303 | */ | |
304 | index = 0; | |
305 | for (index = 0; index < cb->nr_pages; index++) { | |
306 | page = cb->compressed_pages[index]; | |
307 | page->mapping = NULL; | |
308 | page_cache_release(page); | |
309 | } | |
310 | ||
311 | /* finally free the cb struct */ | |
312 | kfree(cb->compressed_pages); | |
313 | kfree(cb); | |
314 | out: | |
315 | bio_put(bio); | |
316 | } | |
317 | ||
318 | /* | |
319 | * worker function to build and submit bios for previously compressed pages. | |
320 | * The corresponding pages in the inode should be marked for writeback | |
321 | * and the compressed pages should have a reference on them for dropping | |
322 | * when the IO is complete. | |
323 | * | |
324 | * This also checksums the file bytes and gets things ready for | |
325 | * the end io hooks. | |
326 | */ | |
327 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
328 | unsigned long len, u64 disk_start, | |
329 | unsigned long compressed_len, | |
330 | struct page **compressed_pages, | |
331 | unsigned long nr_pages) | |
332 | { | |
333 | struct bio *bio = NULL; | |
334 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
335 | struct compressed_bio *cb; | |
336 | unsigned long bytes_left; | |
337 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
338 | int pg_index = 0; | |
339 | struct page *page; | |
340 | u64 first_byte = disk_start; | |
341 | struct block_device *bdev; | |
342 | int ret; | |
343 | int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; | |
344 | ||
345 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
346 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); | |
347 | if (!cb) | |
348 | return -ENOMEM; | |
349 | atomic_set(&cb->pending_bios, 0); | |
350 | cb->errors = 0; | |
351 | cb->inode = inode; | |
352 | cb->start = start; | |
353 | cb->len = len; | |
354 | cb->mirror_num = 0; | |
355 | cb->compressed_pages = compressed_pages; | |
356 | cb->compressed_len = compressed_len; | |
357 | cb->orig_bio = NULL; | |
358 | cb->nr_pages = nr_pages; | |
359 | ||
360 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
361 | ||
362 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
363 | if(!bio) { | |
364 | kfree(cb); | |
365 | return -ENOMEM; | |
366 | } | |
367 | bio->bi_private = cb; | |
368 | bio->bi_end_io = end_compressed_bio_write; | |
369 | atomic_inc(&cb->pending_bios); | |
370 | ||
371 | /* create and submit bios for the compressed pages */ | |
372 | bytes_left = compressed_len; | |
373 | for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { | |
374 | page = compressed_pages[pg_index]; | |
375 | page->mapping = inode->i_mapping; | |
376 | if (bio->bi_size) | |
377 | ret = io_tree->ops->merge_bio_hook(WRITE, page, 0, | |
378 | PAGE_CACHE_SIZE, | |
379 | bio, 0); | |
380 | else | |
381 | ret = 0; | |
382 | ||
383 | page->mapping = NULL; | |
384 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < | |
385 | PAGE_CACHE_SIZE) { | |
386 | bio_get(bio); | |
387 | ||
388 | /* | |
389 | * inc the count before we submit the bio so | |
390 | * we know the end IO handler won't happen before | |
391 | * we inc the count. Otherwise, the cb might get | |
392 | * freed before we're done setting it up | |
393 | */ | |
394 | atomic_inc(&cb->pending_bios); | |
395 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
396 | BUG_ON(ret); /* -ENOMEM */ | |
397 | ||
398 | if (!skip_sum) { | |
399 | ret = btrfs_csum_one_bio(root, inode, bio, | |
400 | start, 1); | |
401 | BUG_ON(ret); /* -ENOMEM */ | |
402 | } | |
403 | ||
404 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); | |
405 | BUG_ON(ret); /* -ENOMEM */ | |
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 | printk("bytes left %lu compress len %lu nr %lu\n", | |
417 | bytes_left, cb->compressed_len, cb->nr_pages); | |
418 | } | |
419 | bytes_left -= PAGE_CACHE_SIZE; | |
420 | first_byte += PAGE_CACHE_SIZE; | |
421 | cond_resched(); | |
422 | } | |
423 | bio_get(bio); | |
424 | ||
425 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
426 | BUG_ON(ret); /* -ENOMEM */ | |
427 | ||
428 | if (!skip_sum) { | |
429 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); | |
430 | BUG_ON(ret); /* -ENOMEM */ | |
431 | } | |
432 | ||
433 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); | |
434 | BUG_ON(ret); /* -ENOMEM */ | |
435 | ||
436 | bio_put(bio); | |
437 | return 0; | |
438 | } | |
439 | ||
440 | static noinline int add_ra_bio_pages(struct inode *inode, | |
441 | u64 compressed_end, | |
442 | struct compressed_bio *cb) | |
443 | { | |
444 | unsigned long end_index; | |
445 | unsigned long pg_index; | |
446 | u64 last_offset; | |
447 | u64 isize = i_size_read(inode); | |
448 | int ret; | |
449 | struct page *page; | |
450 | unsigned long nr_pages = 0; | |
451 | struct extent_map *em; | |
452 | struct address_space *mapping = inode->i_mapping; | |
453 | struct extent_map_tree *em_tree; | |
454 | struct extent_io_tree *tree; | |
455 | u64 end; | |
456 | int misses = 0; | |
457 | ||
458 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; | |
459 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); | |
460 | em_tree = &BTRFS_I(inode)->extent_tree; | |
461 | tree = &BTRFS_I(inode)->io_tree; | |
462 | ||
463 | if (isize == 0) | |
464 | return 0; | |
465 | ||
466 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; | |
467 | ||
468 | while (last_offset < compressed_end) { | |
469 | pg_index = last_offset >> PAGE_CACHE_SHIFT; | |
470 | ||
471 | if (pg_index > end_index) | |
472 | break; | |
473 | ||
474 | rcu_read_lock(); | |
475 | page = radix_tree_lookup(&mapping->page_tree, pg_index); | |
476 | rcu_read_unlock(); | |
477 | if (page) { | |
478 | misses++; | |
479 | if (misses > 4) | |
480 | break; | |
481 | goto next; | |
482 | } | |
483 | ||
484 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & | |
485 | ~__GFP_FS); | |
486 | if (!page) | |
487 | break; | |
488 | ||
489 | if (add_to_page_cache_lru(page, mapping, pg_index, | |
490 | GFP_NOFS)) { | |
491 | page_cache_release(page); | |
492 | goto next; | |
493 | } | |
494 | ||
495 | end = last_offset + PAGE_CACHE_SIZE - 1; | |
496 | /* | |
497 | * at this point, we have a locked page in the page cache | |
498 | * for these bytes in the file. But, we have to make | |
499 | * sure they map to this compressed extent on disk. | |
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_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 | } | |
545 | next: | |
546 | last_offset += PAGE_CACHE_SIZE; | |
547 | } | |
548 | return 0; | |
549 | } | |
550 | ||
551 | /* | |
552 | * for a compressed read, the bio we get passed has all the inode pages | |
553 | * in it. We don't actually do IO on those pages but allocate new ones | |
554 | * to hold the compressed pages on disk. | |
555 | * | |
556 | * bio->bi_sector points to the compressed extent on disk | |
557 | * bio->bi_io_vec points to all of the inode pages | |
558 | * bio->bi_vcnt is a count of pages | |
559 | * | |
560 | * After the compressed pages are read, we copy the bytes into the | |
561 | * bio we were passed and then call the bio end_io calls | |
562 | */ | |
563 | int 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_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 | /* we need the actual starting offset of this extent in the file */ | |
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 = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
621 | PAGE_CACHE_SIZE; | |
622 | cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages, | |
623 | GFP_NOFS); | |
624 | if (!cb->compressed_pages) | |
625 | goto fail1; | |
626 | ||
627 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
628 | ||
629 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { | |
630 | cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | | |
631 | __GFP_HIGHMEM); | |
632 | if (!cb->compressed_pages[pg_index]) { | |
633 | faili = pg_index - 1; | |
634 | ret = -ENOMEM; | |
635 | goto fail2; | |
636 | } | |
637 | } | |
638 | faili = nr_pages - 1; | |
639 | cb->nr_pages = nr_pages; | |
640 | ||
641 | /* In the parent-locked case, we only locked the range we are | |
642 | * interested in. In all other cases, we can opportunistically | |
643 | * cache decompressed data that goes beyond the requested range. */ | |
644 | if (!(bio_flags & EXTENT_BIO_PARENT_LOCKED)) | |
645 | add_ra_bio_pages(inode, em_start + em_len, cb); | |
646 | ||
647 | /* include any pages we added in add_ra-bio_pages */ | |
648 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
649 | cb->len = uncompressed_len; | |
650 | ||
651 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); | |
652 | if (!comp_bio) | |
653 | goto fail2; | |
654 | comp_bio->bi_private = cb; | |
655 | comp_bio->bi_end_io = end_compressed_bio_read; | |
656 | atomic_inc(&cb->pending_bios); | |
657 | ||
658 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { | |
659 | page = cb->compressed_pages[pg_index]; | |
660 | page->mapping = inode->i_mapping; | |
661 | page->index = em_start >> PAGE_CACHE_SHIFT; | |
662 | ||
663 | if (comp_bio->bi_size) | |
664 | ret = tree->ops->merge_bio_hook(READ, page, 0, | |
665 | PAGE_CACHE_SIZE, | |
666 | comp_bio, 0); | |
667 | else | |
668 | ret = 0; | |
669 | ||
670 | page->mapping = NULL; | |
671 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < | |
672 | PAGE_CACHE_SIZE) { | |
673 | bio_get(comp_bio); | |
674 | ||
675 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
676 | BUG_ON(ret); /* -ENOMEM */ | |
677 | ||
678 | /* | |
679 | * inc the count before we submit the bio so | |
680 | * we know the end IO handler won't happen before | |
681 | * we inc the count. Otherwise, the cb might get | |
682 | * freed before we're done setting it up | |
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); /* -ENOMEM */ | |
690 | } | |
691 | sums += (comp_bio->bi_size + root->sectorsize - 1) / | |
692 | root->sectorsize; | |
693 | ||
694 | ret = btrfs_map_bio(root, READ, comp_bio, | |
695 | mirror_num, 0); | |
696 | if (ret) | |
697 | bio_endio(comp_bio, ret); | |
698 | ||
699 | bio_put(comp_bio); | |
700 | ||
701 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
702 | GFP_NOFS); | |
703 | BUG_ON(!comp_bio); | |
704 | comp_bio->bi_private = cb; | |
705 | comp_bio->bi_end_io = end_compressed_bio_read; | |
706 | ||
707 | bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); | |
708 | } | |
709 | cur_disk_byte += PAGE_CACHE_SIZE; | |
710 | } | |
711 | bio_get(comp_bio); | |
712 | ||
713 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
714 | BUG_ON(ret); /* -ENOMEM */ | |
715 | ||
716 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { | |
717 | ret = btrfs_lookup_bio_sums(root, inode, comp_bio, sums); | |
718 | BUG_ON(ret); /* -ENOMEM */ | |
719 | } | |
720 | ||
721 | ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); | |
722 | if (ret) | |
723 | bio_endio(comp_bio, ret); | |
724 | ||
725 | bio_put(comp_bio); | |
726 | return 0; | |
727 | ||
728 | fail2: | |
729 | while (faili >= 0) { | |
730 | __free_page(cb->compressed_pages[faili]); | |
731 | faili--; | |
732 | } | |
733 | ||
734 | kfree(cb->compressed_pages); | |
735 | fail1: | |
736 | kfree(cb); | |
737 | out: | |
738 | free_extent_map(em); | |
739 | return ret; | |
740 | } | |
741 | ||
742 | static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES]; | |
743 | static spinlock_t comp_workspace_lock[BTRFS_COMPRESS_TYPES]; | |
744 | static int comp_num_workspace[BTRFS_COMPRESS_TYPES]; | |
745 | static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES]; | |
746 | static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES]; | |
747 | ||
748 | static struct btrfs_compress_op *btrfs_compress_op[] = { | |
749 | &btrfs_zlib_compress, | |
750 | &btrfs_lzo_compress, | |
751 | }; | |
752 | ||
753 | void __init btrfs_init_compress(void) | |
754 | { | |
755 | int i; | |
756 | ||
757 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
758 | INIT_LIST_HEAD(&comp_idle_workspace[i]); | |
759 | spin_lock_init(&comp_workspace_lock[i]); | |
760 | atomic_set(&comp_alloc_workspace[i], 0); | |
761 | init_waitqueue_head(&comp_workspace_wait[i]); | |
762 | } | |
763 | } | |
764 | ||
765 | /* | |
766 | * this finds an available workspace or allocates a new one | |
767 | * ERR_PTR is returned if things go bad. | |
768 | */ | |
769 | static struct list_head *find_workspace(int type) | |
770 | { | |
771 | struct list_head *workspace; | |
772 | int cpus = num_online_cpus(); | |
773 | int idx = type - 1; | |
774 | ||
775 | struct list_head *idle_workspace = &comp_idle_workspace[idx]; | |
776 | spinlock_t *workspace_lock = &comp_workspace_lock[idx]; | |
777 | atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; | |
778 | wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; | |
779 | int *num_workspace = &comp_num_workspace[idx]; | |
780 | again: | |
781 | spin_lock(workspace_lock); | |
782 | if (!list_empty(idle_workspace)) { | |
783 | workspace = idle_workspace->next; | |
784 | list_del(workspace); | |
785 | (*num_workspace)--; | |
786 | spin_unlock(workspace_lock); | |
787 | return workspace; | |
788 | ||
789 | } | |
790 | if (atomic_read(alloc_workspace) > cpus) { | |
791 | DEFINE_WAIT(wait); | |
792 | ||
793 | spin_unlock(workspace_lock); | |
794 | prepare_to_wait(workspace_wait, &wait, TASK_UNINTERRUPTIBLE); | |
795 | if (atomic_read(alloc_workspace) > cpus && !*num_workspace) | |
796 | schedule(); | |
797 | finish_wait(workspace_wait, &wait); | |
798 | goto again; | |
799 | } | |
800 | atomic_inc(alloc_workspace); | |
801 | spin_unlock(workspace_lock); | |
802 | ||
803 | workspace = btrfs_compress_op[idx]->alloc_workspace(); | |
804 | if (IS_ERR(workspace)) { | |
805 | atomic_dec(alloc_workspace); | |
806 | wake_up(workspace_wait); | |
807 | } | |
808 | return workspace; | |
809 | } | |
810 | ||
811 | /* | |
812 | * put a workspace struct back on the list or free it if we have enough | |
813 | * idle ones sitting around | |
814 | */ | |
815 | static void free_workspace(int type, struct list_head *workspace) | |
816 | { | |
817 | int idx = type - 1; | |
818 | struct list_head *idle_workspace = &comp_idle_workspace[idx]; | |
819 | spinlock_t *workspace_lock = &comp_workspace_lock[idx]; | |
820 | atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; | |
821 | wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; | |
822 | int *num_workspace = &comp_num_workspace[idx]; | |
823 | ||
824 | spin_lock(workspace_lock); | |
825 | if (*num_workspace < num_online_cpus()) { | |
826 | list_add_tail(workspace, idle_workspace); | |
827 | (*num_workspace)++; | |
828 | spin_unlock(workspace_lock); | |
829 | goto wake; | |
830 | } | |
831 | spin_unlock(workspace_lock); | |
832 | ||
833 | btrfs_compress_op[idx]->free_workspace(workspace); | |
834 | atomic_dec(alloc_workspace); | |
835 | wake: | |
836 | smp_mb(); | |
837 | if (waitqueue_active(workspace_wait)) | |
838 | wake_up(workspace_wait); | |
839 | } | |
840 | ||
841 | /* | |
842 | * cleanup function for module exit | |
843 | */ | |
844 | static void free_workspaces(void) | |
845 | { | |
846 | struct list_head *workspace; | |
847 | int i; | |
848 | ||
849 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
850 | while (!list_empty(&comp_idle_workspace[i])) { | |
851 | workspace = comp_idle_workspace[i].next; | |
852 | list_del(workspace); | |
853 | btrfs_compress_op[i]->free_workspace(workspace); | |
854 | atomic_dec(&comp_alloc_workspace[i]); | |
855 | } | |
856 | } | |
857 | } | |
858 | ||
859 | /* | |
860 | * given an address space and start/len, compress the bytes. | |
861 | * | |
862 | * pages are allocated to hold the compressed result and stored | |
863 | * in 'pages' | |
864 | * | |
865 | * out_pages is used to return the number of pages allocated. There | |
866 | * may be pages allocated even if we return an error | |
867 | * | |
868 | * total_in is used to return the number of bytes actually read. It | |
869 | * may be smaller then len if we had to exit early because we | |
870 | * ran out of room in the pages array or because we cross the | |
871 | * max_out threshold. | |
872 | * | |
873 | * total_out is used to return the total number of compressed bytes | |
874 | * | |
875 | * max_out tells us the max number of bytes that we're allowed to | |
876 | * stuff into pages | |
877 | */ | |
878 | int btrfs_compress_pages(int type, struct address_space *mapping, | |
879 | u64 start, unsigned long len, | |
880 | struct page **pages, | |
881 | unsigned long nr_dest_pages, | |
882 | unsigned long *out_pages, | |
883 | unsigned long *total_in, | |
884 | unsigned long *total_out, | |
885 | unsigned long max_out) | |
886 | { | |
887 | struct list_head *workspace; | |
888 | int ret; | |
889 | ||
890 | workspace = find_workspace(type); | |
891 | if (IS_ERR(workspace)) | |
892 | return -1; | |
893 | ||
894 | ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, | |
895 | start, len, pages, | |
896 | nr_dest_pages, out_pages, | |
897 | total_in, total_out, | |
898 | max_out); | |
899 | free_workspace(type, workspace); | |
900 | return ret; | |
901 | } | |
902 | ||
903 | /* | |
904 | * pages_in is an array of pages with compressed data. | |
905 | * | |
906 | * disk_start is the starting logical offset of this array in the file | |
907 | * | |
908 | * bvec is a bio_vec of pages from the file that we want to decompress into | |
909 | * | |
910 | * vcnt is the count of pages in the biovec | |
911 | * | |
912 | * srclen is the number of bytes in pages_in | |
913 | * | |
914 | * The basic idea is that we have a bio that was created by readpages. | |
915 | * The pages in the bio are for the uncompressed data, and they may not | |
916 | * be contiguous. They all correspond to the range of bytes covered by | |
917 | * the compressed extent. | |
918 | */ | |
919 | static int btrfs_decompress_biovec(int type, struct page **pages_in, | |
920 | u64 disk_start, struct bio_vec *bvec, | |
921 | int vcnt, size_t srclen) | |
922 | { | |
923 | struct list_head *workspace; | |
924 | int ret; | |
925 | ||
926 | workspace = find_workspace(type); | |
927 | if (IS_ERR(workspace)) | |
928 | return -ENOMEM; | |
929 | ||
930 | ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in, | |
931 | disk_start, | |
932 | bvec, vcnt, srclen); | |
933 | free_workspace(type, workspace); | |
934 | return ret; | |
935 | } | |
936 | ||
937 | /* | |
938 | * a less complex decompression routine. Our compressed data fits in a | |
939 | * single page, and we want to read a single page out of it. | |
940 | * start_byte tells us the offset into the compressed data we're interested in | |
941 | */ | |
942 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, | |
943 | unsigned long start_byte, size_t srclen, size_t destlen) | |
944 | { | |
945 | struct list_head *workspace; | |
946 | int ret; | |
947 | ||
948 | workspace = find_workspace(type); | |
949 | if (IS_ERR(workspace)) | |
950 | return -ENOMEM; | |
951 | ||
952 | ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, | |
953 | dest_page, start_byte, | |
954 | srclen, destlen); | |
955 | ||
956 | free_workspace(type, workspace); | |
957 | return ret; | |
958 | } | |
959 | ||
960 | void btrfs_exit_compress(void) | |
961 | { | |
962 | free_workspaces(); | |
963 | } | |
964 | ||
965 | /* | |
966 | * Copy uncompressed data from working buffer to pages. | |
967 | * | |
968 | * buf_start is the byte offset we're of the start of our workspace buffer. | |
969 | * | |
970 | * total_out is the last byte of the buffer | |
971 | */ | |
972 | int btrfs_decompress_buf2page(char *buf, unsigned long buf_start, | |
973 | unsigned long total_out, u64 disk_start, | |
974 | struct bio_vec *bvec, int vcnt, | |
975 | unsigned long *pg_index, | |
976 | unsigned long *pg_offset) | |
977 | { | |
978 | unsigned long buf_offset; | |
979 | unsigned long current_buf_start; | |
980 | unsigned long start_byte; | |
981 | unsigned long working_bytes = total_out - buf_start; | |
982 | unsigned long bytes; | |
983 | char *kaddr; | |
984 | struct page *page_out = bvec[*pg_index].bv_page; | |
985 | ||
986 | /* | |
987 | * start byte is the first byte of the page we're currently | |
988 | * copying into relative to the start of the compressed data. | |
989 | */ | |
990 | start_byte = page_offset(page_out) - disk_start; | |
991 | ||
992 | /* we haven't yet hit data corresponding to this page */ | |
993 | if (total_out <= start_byte) | |
994 | return 1; | |
995 | ||
996 | /* | |
997 | * the start of the data we care about is offset into | |
998 | * the middle of our working buffer | |
999 | */ | |
1000 | if (total_out > start_byte && buf_start < start_byte) { | |
1001 | buf_offset = start_byte - buf_start; | |
1002 | working_bytes -= buf_offset; | |
1003 | } else { | |
1004 | buf_offset = 0; | |
1005 | } | |
1006 | current_buf_start = buf_start; | |
1007 | ||
1008 | /* copy bytes from the working buffer into the pages */ | |
1009 | while (working_bytes > 0) { | |
1010 | bytes = min(PAGE_CACHE_SIZE - *pg_offset, | |
1011 | PAGE_CACHE_SIZE - buf_offset); | |
1012 | bytes = min(bytes, working_bytes); | |
1013 | kaddr = kmap_atomic(page_out); | |
1014 | memcpy(kaddr + *pg_offset, buf + buf_offset, bytes); | |
1015 | kunmap_atomic(kaddr); | |
1016 | flush_dcache_page(page_out); | |
1017 | ||
1018 | *pg_offset += bytes; | |
1019 | buf_offset += bytes; | |
1020 | working_bytes -= bytes; | |
1021 | current_buf_start += bytes; | |
1022 | ||
1023 | /* check if we need to pick another page */ | |
1024 | if (*pg_offset == PAGE_CACHE_SIZE) { | |
1025 | (*pg_index)++; | |
1026 | if (*pg_index >= vcnt) | |
1027 | return 0; | |
1028 | ||
1029 | page_out = bvec[*pg_index].bv_page; | |
1030 | *pg_offset = 0; | |
1031 | start_byte = page_offset(page_out) - disk_start; | |
1032 | ||
1033 | /* | |
1034 | * make sure our new page is covered by this | |
1035 | * working buffer | |
1036 | */ | |
1037 | if (total_out <= start_byte) | |
1038 | return 1; | |
1039 | ||
1040 | /* | |
1041 | * the next page in the biovec might not be adjacent | |
1042 | * to the last page, but it might still be found | |
1043 | * inside this working buffer. bump our offset pointer | |
1044 | */ | |
1045 | if (total_out > start_byte && | |
1046 | current_buf_start < start_byte) { | |
1047 | buf_offset = start_byte - buf_start; | |
1048 | working_bytes = total_out - start_byte; | |
1049 | current_buf_start = buf_start + buf_offset; | |
1050 | } | |
1051 | } | |
1052 | } | |
1053 | ||
1054 | return 1; | |
1055 | } |