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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> | |
c8b97818 CM |
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> | |
5a0e3ad6 | 34 | #include <linux/slab.h> |
4b4e25f2 | 35 | #include "compat.h" |
c8b97818 CM |
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" | |
c8b97818 CM |
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 | ||
261507a0 LZ |
65 | /* the compression algorithm for this bio */ |
66 | int compress_type; | |
67 | ||
c8b97818 CM |
68 | /* number of compressed pages in the array */ |
69 | unsigned long nr_pages; | |
70 | ||
71 | /* IO errors */ | |
72 | int errors; | |
d20f7043 | 73 | int mirror_num; |
c8b97818 CM |
74 | |
75 | /* for reads, this is the bio we are copying the data into */ | |
76 | struct bio *orig_bio; | |
d20f7043 CM |
77 | |
78 | /* | |
79 | * the start of a variable length array of checksums only | |
80 | * used by reads | |
81 | */ | |
82 | u32 sums; | |
c8b97818 CM |
83 | }; |
84 | ||
d20f7043 CM |
85 | static 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 | ||
c8b97818 CM |
94 | static struct bio *compressed_bio_alloc(struct block_device *bdev, |
95 | u64 first_byte, gfp_t gfp_flags) | |
96 | { | |
c8b97818 CM |
97 | int nr_vecs; |
98 | ||
99 | nr_vecs = bio_get_nr_vecs(bdev); | |
88f794ed | 100 | return btrfs_bio_alloc(bdev, first_byte >> 9, nr_vecs, gfp_flags); |
c8b97818 CM |
101 | } |
102 | ||
d20f7043 CM |
103 | static 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 | ||
6cbff00f | 115 | if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
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) { | |
d397712b CM |
128 | printk(KERN_INFO "btrfs csum failed ino %lu " |
129 | "extent %llu csum %u " | |
d20f7043 CM |
130 | "wanted %u mirror %d\n", inode->i_ino, |
131 | (unsigned long long)disk_start, | |
132 | csum, *cb_sum, cb->mirror_num); | |
133 | ret = -EIO; | |
134 | goto fail; | |
135 | } | |
136 | cb_sum++; | |
137 | ||
138 | } | |
139 | ret = 0; | |
140 | fail: | |
141 | return ret; | |
142 | } | |
143 | ||
c8b97818 CM |
144 | /* when we finish reading compressed pages from the disk, we |
145 | * decompress them and then run the bio end_io routines on the | |
146 | * decompressed pages (in the inode address space). | |
147 | * | |
148 | * This allows the checksumming and other IO error handling routines | |
149 | * to work normally | |
150 | * | |
151 | * The compressed pages are freed here, and it must be run | |
152 | * in process context | |
153 | */ | |
154 | static void end_compressed_bio_read(struct bio *bio, int err) | |
155 | { | |
c8b97818 CM |
156 | struct compressed_bio *cb = bio->bi_private; |
157 | struct inode *inode; | |
158 | struct page *page; | |
159 | unsigned long index; | |
160 | int ret; | |
161 | ||
162 | if (err) | |
163 | cb->errors = 1; | |
164 | ||
165 | /* if there are more bios still pending for this compressed | |
166 | * extent, just exit | |
167 | */ | |
168 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
169 | goto out; | |
170 | ||
d20f7043 CM |
171 | inode = cb->inode; |
172 | ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); | |
173 | if (ret) | |
174 | goto csum_failed; | |
175 | ||
c8b97818 CM |
176 | /* ok, we're the last bio for this extent, lets start |
177 | * the decompression. | |
178 | */ | |
261507a0 LZ |
179 | ret = btrfs_decompress_biovec(cb->compress_type, |
180 | cb->compressed_pages, | |
181 | cb->start, | |
182 | cb->orig_bio->bi_io_vec, | |
183 | cb->orig_bio->bi_vcnt, | |
184 | cb->compressed_len); | |
d20f7043 | 185 | csum_failed: |
c8b97818 CM |
186 | if (ret) |
187 | cb->errors = 1; | |
188 | ||
189 | /* release the compressed pages */ | |
190 | index = 0; | |
191 | for (index = 0; index < cb->nr_pages; index++) { | |
192 | page = cb->compressed_pages[index]; | |
193 | page->mapping = NULL; | |
194 | page_cache_release(page); | |
195 | } | |
196 | ||
197 | /* do io completion on the original bio */ | |
771ed689 | 198 | if (cb->errors) { |
c8b97818 | 199 | bio_io_error(cb->orig_bio); |
d20f7043 CM |
200 | } else { |
201 | int bio_index = 0; | |
202 | struct bio_vec *bvec = cb->orig_bio->bi_io_vec; | |
203 | ||
204 | /* | |
205 | * we have verified the checksum already, set page | |
206 | * checked so the end_io handlers know about it | |
207 | */ | |
d397712b | 208 | while (bio_index < cb->orig_bio->bi_vcnt) { |
d20f7043 CM |
209 | SetPageChecked(bvec->bv_page); |
210 | bvec++; | |
211 | bio_index++; | |
212 | } | |
c8b97818 | 213 | bio_endio(cb->orig_bio, 0); |
d20f7043 | 214 | } |
c8b97818 CM |
215 | |
216 | /* finally free the cb struct */ | |
217 | kfree(cb->compressed_pages); | |
218 | kfree(cb); | |
219 | out: | |
220 | bio_put(bio); | |
221 | } | |
222 | ||
223 | /* | |
224 | * Clear the writeback bits on all of the file | |
225 | * pages for a compressed write | |
226 | */ | |
227 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, | |
228 | unsigned long ram_size) | |
229 | { | |
230 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
231 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
232 | struct page *pages[16]; | |
233 | unsigned long nr_pages = end_index - index + 1; | |
234 | int i; | |
235 | int ret; | |
236 | ||
d397712b | 237 | while (nr_pages > 0) { |
c8b97818 | 238 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
239 | min_t(unsigned long, |
240 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
241 | if (ret == 0) { |
242 | nr_pages -= 1; | |
243 | index += 1; | |
244 | continue; | |
245 | } | |
246 | for (i = 0; i < ret; i++) { | |
247 | end_page_writeback(pages[i]); | |
248 | page_cache_release(pages[i]); | |
249 | } | |
250 | nr_pages -= ret; | |
251 | index += ret; | |
252 | } | |
253 | /* the inode may be gone now */ | |
254 | return 0; | |
255 | } | |
256 | ||
257 | /* | |
258 | * do the cleanup once all the compressed pages hit the disk. | |
259 | * This will clear writeback on the file pages and free the compressed | |
260 | * pages. | |
261 | * | |
262 | * This also calls the writeback end hooks for the file pages so that | |
263 | * metadata and checksums can be updated in the file. | |
264 | */ | |
265 | static void end_compressed_bio_write(struct bio *bio, int err) | |
266 | { | |
267 | struct extent_io_tree *tree; | |
268 | struct compressed_bio *cb = bio->bi_private; | |
269 | struct inode *inode; | |
270 | struct page *page; | |
271 | unsigned long index; | |
272 | ||
273 | if (err) | |
274 | cb->errors = 1; | |
275 | ||
276 | /* if there are more bios still pending for this compressed | |
277 | * extent, just exit | |
278 | */ | |
279 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
280 | goto out; | |
281 | ||
282 | /* ok, we're the last bio for this extent, step one is to | |
283 | * call back into the FS and do all the end_io operations | |
284 | */ | |
285 | inode = cb->inode; | |
286 | tree = &BTRFS_I(inode)->io_tree; | |
70b99e69 | 287 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
c8b97818 CM |
288 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
289 | cb->start, | |
290 | cb->start + cb->len - 1, | |
291 | NULL, 1); | |
70b99e69 | 292 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 CM |
293 | |
294 | end_compressed_writeback(inode, cb->start, cb->len); | |
295 | /* note, our inode could be gone now */ | |
296 | ||
297 | /* | |
298 | * release the compressed pages, these came from alloc_page and | |
299 | * are not attached to the inode at all | |
300 | */ | |
301 | index = 0; | |
302 | for (index = 0; index < cb->nr_pages; index++) { | |
303 | page = cb->compressed_pages[index]; | |
304 | page->mapping = NULL; | |
305 | page_cache_release(page); | |
306 | } | |
307 | ||
308 | /* finally free the cb struct */ | |
309 | kfree(cb->compressed_pages); | |
310 | kfree(cb); | |
311 | out: | |
312 | bio_put(bio); | |
313 | } | |
314 | ||
315 | /* | |
316 | * worker function to build and submit bios for previously compressed pages. | |
317 | * The corresponding pages in the inode should be marked for writeback | |
318 | * and the compressed pages should have a reference on them for dropping | |
319 | * when the IO is complete. | |
320 | * | |
321 | * This also checksums the file bytes and gets things ready for | |
322 | * the end io hooks. | |
323 | */ | |
324 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
325 | unsigned long len, u64 disk_start, | |
326 | unsigned long compressed_len, | |
327 | struct page **compressed_pages, | |
328 | unsigned long nr_pages) | |
329 | { | |
330 | struct bio *bio = NULL; | |
331 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
332 | struct compressed_bio *cb; | |
333 | unsigned long bytes_left; | |
334 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
335 | int page_index = 0; | |
336 | struct page *page; | |
337 | u64 first_byte = disk_start; | |
338 | struct block_device *bdev; | |
339 | int ret; | |
340 | ||
341 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
d20f7043 | 342 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); |
c8b97818 CM |
343 | atomic_set(&cb->pending_bios, 0); |
344 | cb->errors = 0; | |
345 | cb->inode = inode; | |
346 | cb->start = start; | |
347 | cb->len = len; | |
d20f7043 | 348 | cb->mirror_num = 0; |
c8b97818 CM |
349 | cb->compressed_pages = compressed_pages; |
350 | cb->compressed_len = compressed_len; | |
351 | cb->orig_bio = NULL; | |
352 | cb->nr_pages = nr_pages; | |
353 | ||
354 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
355 | ||
c8b97818 CM |
356 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
357 | bio->bi_private = cb; | |
358 | bio->bi_end_io = end_compressed_bio_write; | |
359 | atomic_inc(&cb->pending_bios); | |
360 | ||
361 | /* create and submit bios for the compressed pages */ | |
362 | bytes_left = compressed_len; | |
cfbc246e | 363 | for (page_index = 0; page_index < cb->nr_pages; page_index++) { |
c8b97818 CM |
364 | page = compressed_pages[page_index]; |
365 | page->mapping = inode->i_mapping; | |
366 | if (bio->bi_size) | |
367 | ret = io_tree->ops->merge_bio_hook(page, 0, | |
368 | PAGE_CACHE_SIZE, | |
369 | bio, 0); | |
370 | else | |
371 | ret = 0; | |
372 | ||
70b99e69 | 373 | page->mapping = NULL; |
c8b97818 CM |
374 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < |
375 | PAGE_CACHE_SIZE) { | |
376 | bio_get(bio); | |
377 | ||
af09abfe CM |
378 | /* |
379 | * inc the count before we submit the bio so | |
380 | * we know the end IO handler won't happen before | |
381 | * we inc the count. Otherwise, the cb might get | |
382 | * freed before we're done setting it up | |
383 | */ | |
384 | atomic_inc(&cb->pending_bios); | |
c8b97818 CM |
385 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); |
386 | BUG_ON(ret); | |
387 | ||
d20f7043 CM |
388 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
389 | BUG_ON(ret); | |
390 | ||
c8b97818 CM |
391 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
392 | BUG_ON(ret); | |
393 | ||
394 | bio_put(bio); | |
395 | ||
396 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
c8b97818 CM |
397 | bio->bi_private = cb; |
398 | bio->bi_end_io = end_compressed_bio_write; | |
399 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
400 | } | |
cfbc246e CM |
401 | if (bytes_left < PAGE_CACHE_SIZE) { |
402 | printk("bytes left %lu compress len %lu nr %lu\n", | |
403 | bytes_left, cb->compressed_len, cb->nr_pages); | |
404 | } | |
c8b97818 CM |
405 | bytes_left -= PAGE_CACHE_SIZE; |
406 | first_byte += PAGE_CACHE_SIZE; | |
771ed689 | 407 | cond_resched(); |
c8b97818 CM |
408 | } |
409 | bio_get(bio); | |
410 | ||
411 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
412 | BUG_ON(ret); | |
413 | ||
d20f7043 CM |
414 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
415 | BUG_ON(ret); | |
416 | ||
c8b97818 CM |
417 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
418 | BUG_ON(ret); | |
419 | ||
420 | bio_put(bio); | |
421 | return 0; | |
422 | } | |
423 | ||
771ed689 CM |
424 | static noinline int add_ra_bio_pages(struct inode *inode, |
425 | u64 compressed_end, | |
426 | struct compressed_bio *cb) | |
427 | { | |
428 | unsigned long end_index; | |
429 | unsigned long page_index; | |
430 | u64 last_offset; | |
431 | u64 isize = i_size_read(inode); | |
432 | int ret; | |
433 | struct page *page; | |
434 | unsigned long nr_pages = 0; | |
435 | struct extent_map *em; | |
436 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
437 | struct extent_map_tree *em_tree; |
438 | struct extent_io_tree *tree; | |
439 | u64 end; | |
440 | int misses = 0; | |
441 | ||
442 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; | |
443 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); | |
444 | em_tree = &BTRFS_I(inode)->extent_tree; | |
445 | tree = &BTRFS_I(inode)->io_tree; | |
446 | ||
447 | if (isize == 0) | |
448 | return 0; | |
449 | ||
450 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; | |
451 | ||
d397712b | 452 | while (last_offset < compressed_end) { |
771ed689 CM |
453 | page_index = last_offset >> PAGE_CACHE_SHIFT; |
454 | ||
455 | if (page_index > end_index) | |
456 | break; | |
457 | ||
458 | rcu_read_lock(); | |
459 | page = radix_tree_lookup(&mapping->page_tree, page_index); | |
460 | rcu_read_unlock(); | |
461 | if (page) { | |
462 | misses++; | |
463 | if (misses > 4) | |
464 | break; | |
465 | goto next; | |
466 | } | |
467 | ||
28ecb609 NP |
468 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & |
469 | ~__GFP_FS); | |
771ed689 CM |
470 | if (!page) |
471 | break; | |
472 | ||
28ecb609 NP |
473 | if (add_to_page_cache_lru(page, mapping, page_index, |
474 | GFP_NOFS)) { | |
771ed689 CM |
475 | page_cache_release(page); |
476 | goto next; | |
477 | } | |
478 | ||
771ed689 CM |
479 | end = last_offset + PAGE_CACHE_SIZE - 1; |
480 | /* | |
481 | * at this point, we have a locked page in the page cache | |
482 | * for these bytes in the file. But, we have to make | |
483 | * sure they map to this compressed extent on disk. | |
484 | */ | |
485 | set_page_extent_mapped(page); | |
486 | lock_extent(tree, last_offset, end, GFP_NOFS); | |
890871be | 487 | read_lock(&em_tree->lock); |
771ed689 CM |
488 | em = lookup_extent_mapping(em_tree, last_offset, |
489 | PAGE_CACHE_SIZE); | |
890871be | 490 | read_unlock(&em_tree->lock); |
771ed689 CM |
491 | |
492 | if (!em || last_offset < em->start || | |
493 | (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || | |
494 | (em->block_start >> 9) != cb->orig_bio->bi_sector) { | |
495 | free_extent_map(em); | |
496 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
497 | unlock_page(page); | |
498 | page_cache_release(page); | |
499 | break; | |
500 | } | |
501 | free_extent_map(em); | |
502 | ||
503 | if (page->index == end_index) { | |
504 | char *userpage; | |
505 | size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); | |
506 | ||
507 | if (zero_offset) { | |
508 | int zeros; | |
509 | zeros = PAGE_CACHE_SIZE - zero_offset; | |
510 | userpage = kmap_atomic(page, KM_USER0); | |
511 | memset(userpage + zero_offset, 0, zeros); | |
512 | flush_dcache_page(page); | |
513 | kunmap_atomic(userpage, KM_USER0); | |
514 | } | |
515 | } | |
516 | ||
517 | ret = bio_add_page(cb->orig_bio, page, | |
518 | PAGE_CACHE_SIZE, 0); | |
519 | ||
520 | if (ret == PAGE_CACHE_SIZE) { | |
521 | nr_pages++; | |
522 | page_cache_release(page); | |
523 | } else { | |
524 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
525 | unlock_page(page); | |
526 | page_cache_release(page); | |
527 | break; | |
528 | } | |
529 | next: | |
530 | last_offset += PAGE_CACHE_SIZE; | |
531 | } | |
771ed689 CM |
532 | return 0; |
533 | } | |
534 | ||
c8b97818 CM |
535 | /* |
536 | * for a compressed read, the bio we get passed has all the inode pages | |
537 | * in it. We don't actually do IO on those pages but allocate new ones | |
538 | * to hold the compressed pages on disk. | |
539 | * | |
540 | * bio->bi_sector points to the compressed extent on disk | |
541 | * bio->bi_io_vec points to all of the inode pages | |
542 | * bio->bi_vcnt is a count of pages | |
543 | * | |
544 | * After the compressed pages are read, we copy the bytes into the | |
545 | * bio we were passed and then call the bio end_io calls | |
546 | */ | |
547 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
548 | int mirror_num, unsigned long bio_flags) | |
549 | { | |
550 | struct extent_io_tree *tree; | |
551 | struct extent_map_tree *em_tree; | |
552 | struct compressed_bio *cb; | |
553 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
554 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
555 | unsigned long compressed_len; | |
556 | unsigned long nr_pages; | |
557 | unsigned long page_index; | |
558 | struct page *page; | |
559 | struct block_device *bdev; | |
560 | struct bio *comp_bio; | |
561 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; | |
e04ca626 CM |
562 | u64 em_len; |
563 | u64 em_start; | |
c8b97818 | 564 | struct extent_map *em; |
6b82ce8d | 565 | int ret = -ENOMEM; |
d20f7043 | 566 | u32 *sums; |
c8b97818 CM |
567 | |
568 | tree = &BTRFS_I(inode)->io_tree; | |
569 | em_tree = &BTRFS_I(inode)->extent_tree; | |
570 | ||
571 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 572 | read_lock(&em_tree->lock); |
c8b97818 CM |
573 | em = lookup_extent_mapping(em_tree, |
574 | page_offset(bio->bi_io_vec->bv_page), | |
575 | PAGE_CACHE_SIZE); | |
890871be | 576 | read_unlock(&em_tree->lock); |
c8b97818 | 577 | |
d20f7043 CM |
578 | compressed_len = em->block_len; |
579 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); | |
6b82ce8d | 580 | if (!cb) |
581 | goto out; | |
582 | ||
c8b97818 CM |
583 | atomic_set(&cb->pending_bios, 0); |
584 | cb->errors = 0; | |
585 | cb->inode = inode; | |
d20f7043 CM |
586 | cb->mirror_num = mirror_num; |
587 | sums = &cb->sums; | |
c8b97818 | 588 | |
ff5b7ee3 | 589 | cb->start = em->orig_start; |
e04ca626 CM |
590 | em_len = em->len; |
591 | em_start = em->start; | |
d20f7043 | 592 | |
c8b97818 | 593 | free_extent_map(em); |
e04ca626 | 594 | em = NULL; |
c8b97818 CM |
595 | |
596 | cb->len = uncompressed_len; | |
597 | cb->compressed_len = compressed_len; | |
261507a0 | 598 | cb->compress_type = extent_compress_type(bio_flags); |
c8b97818 CM |
599 | cb->orig_bio = bio; |
600 | ||
601 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
602 | PAGE_CACHE_SIZE; | |
6b82ce8d | 603 | cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages, |
c8b97818 | 604 | GFP_NOFS); |
6b82ce8d | 605 | if (!cb->compressed_pages) |
606 | goto fail1; | |
607 | ||
c8b97818 CM |
608 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; |
609 | ||
610 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
611 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | | |
612 | __GFP_HIGHMEM); | |
6b82ce8d | 613 | if (!cb->compressed_pages[page_index]) |
614 | goto fail2; | |
c8b97818 CM |
615 | } |
616 | cb->nr_pages = nr_pages; | |
617 | ||
e04ca626 | 618 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 619 | |
771ed689 CM |
620 | /* include any pages we added in add_ra-bio_pages */ |
621 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
622 | cb->len = uncompressed_len; | |
623 | ||
c8b97818 | 624 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
6b82ce8d | 625 | if (!comp_bio) |
626 | goto fail2; | |
c8b97818 CM |
627 | comp_bio->bi_private = cb; |
628 | comp_bio->bi_end_io = end_compressed_bio_read; | |
629 | atomic_inc(&cb->pending_bios); | |
630 | ||
631 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
632 | page = cb->compressed_pages[page_index]; | |
633 | page->mapping = inode->i_mapping; | |
d20f7043 CM |
634 | page->index = em_start >> PAGE_CACHE_SHIFT; |
635 | ||
c8b97818 CM |
636 | if (comp_bio->bi_size) |
637 | ret = tree->ops->merge_bio_hook(page, 0, | |
638 | PAGE_CACHE_SIZE, | |
639 | comp_bio, 0); | |
640 | else | |
641 | ret = 0; | |
642 | ||
70b99e69 | 643 | page->mapping = NULL; |
c8b97818 CM |
644 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < |
645 | PAGE_CACHE_SIZE) { | |
646 | bio_get(comp_bio); | |
647 | ||
648 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
649 | BUG_ON(ret); | |
650 | ||
af09abfe CM |
651 | /* |
652 | * inc the count before we submit the bio so | |
653 | * we know the end IO handler won't happen before | |
654 | * we inc the count. Otherwise, the cb might get | |
655 | * freed before we're done setting it up | |
656 | */ | |
657 | atomic_inc(&cb->pending_bios); | |
658 | ||
6cbff00f | 659 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
d20f7043 CM |
660 | btrfs_lookup_bio_sums(root, inode, comp_bio, |
661 | sums); | |
662 | } | |
663 | sums += (comp_bio->bi_size + root->sectorsize - 1) / | |
664 | root->sectorsize; | |
665 | ||
666 | ret = btrfs_map_bio(root, READ, comp_bio, | |
667 | mirror_num, 0); | |
c8b97818 CM |
668 | BUG_ON(ret); |
669 | ||
670 | bio_put(comp_bio); | |
671 | ||
672 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
673 | GFP_NOFS); | |
771ed689 CM |
674 | comp_bio->bi_private = cb; |
675 | comp_bio->bi_end_io = end_compressed_bio_read; | |
676 | ||
677 | bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); | |
c8b97818 CM |
678 | } |
679 | cur_disk_byte += PAGE_CACHE_SIZE; | |
680 | } | |
681 | bio_get(comp_bio); | |
682 | ||
683 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
684 | BUG_ON(ret); | |
685 | ||
6cbff00f | 686 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) |
d20f7043 | 687 | btrfs_lookup_bio_sums(root, inode, comp_bio, sums); |
d20f7043 CM |
688 | |
689 | ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); | |
c8b97818 CM |
690 | BUG_ON(ret); |
691 | ||
692 | bio_put(comp_bio); | |
693 | return 0; | |
6b82ce8d | 694 | |
695 | fail2: | |
696 | for (page_index = 0; page_index < nr_pages; page_index++) | |
697 | free_page((unsigned long)cb->compressed_pages[page_index]); | |
698 | ||
699 | kfree(cb->compressed_pages); | |
700 | fail1: | |
701 | kfree(cb); | |
702 | out: | |
703 | free_extent_map(em); | |
704 | return ret; | |
c8b97818 | 705 | } |
261507a0 LZ |
706 | |
707 | static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES]; | |
708 | static spinlock_t comp_workspace_lock[BTRFS_COMPRESS_TYPES]; | |
709 | static int comp_num_workspace[BTRFS_COMPRESS_TYPES]; | |
710 | static atomic_t comp_alloc_workspace[BTRFS_COMPRESS_TYPES]; | |
711 | static wait_queue_head_t comp_workspace_wait[BTRFS_COMPRESS_TYPES]; | |
712 | ||
713 | struct btrfs_compress_op *btrfs_compress_op[] = { | |
714 | &btrfs_zlib_compress, | |
a6fa6fae | 715 | &btrfs_lzo_compress, |
261507a0 LZ |
716 | }; |
717 | ||
718 | int __init btrfs_init_compress(void) | |
719 | { | |
720 | int i; | |
721 | ||
722 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
723 | INIT_LIST_HEAD(&comp_idle_workspace[i]); | |
724 | spin_lock_init(&comp_workspace_lock[i]); | |
725 | atomic_set(&comp_alloc_workspace[i], 0); | |
726 | init_waitqueue_head(&comp_workspace_wait[i]); | |
727 | } | |
728 | return 0; | |
729 | } | |
730 | ||
731 | /* | |
732 | * this finds an available workspace or allocates a new one | |
733 | * ERR_PTR is returned if things go bad. | |
734 | */ | |
735 | static struct list_head *find_workspace(int type) | |
736 | { | |
737 | struct list_head *workspace; | |
738 | int cpus = num_online_cpus(); | |
739 | int idx = type - 1; | |
740 | ||
741 | struct list_head *idle_workspace = &comp_idle_workspace[idx]; | |
742 | spinlock_t *workspace_lock = &comp_workspace_lock[idx]; | |
743 | atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; | |
744 | wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; | |
745 | int *num_workspace = &comp_num_workspace[idx]; | |
746 | again: | |
747 | spin_lock(workspace_lock); | |
748 | if (!list_empty(idle_workspace)) { | |
749 | workspace = idle_workspace->next; | |
750 | list_del(workspace); | |
751 | (*num_workspace)--; | |
752 | spin_unlock(workspace_lock); | |
753 | return workspace; | |
754 | ||
755 | } | |
756 | if (atomic_read(alloc_workspace) > cpus) { | |
757 | DEFINE_WAIT(wait); | |
758 | ||
759 | spin_unlock(workspace_lock); | |
760 | prepare_to_wait(workspace_wait, &wait, TASK_UNINTERRUPTIBLE); | |
761 | if (atomic_read(alloc_workspace) > cpus && !*num_workspace) | |
762 | schedule(); | |
763 | finish_wait(workspace_wait, &wait); | |
764 | goto again; | |
765 | } | |
766 | atomic_inc(alloc_workspace); | |
767 | spin_unlock(workspace_lock); | |
768 | ||
769 | workspace = btrfs_compress_op[idx]->alloc_workspace(); | |
770 | if (IS_ERR(workspace)) { | |
771 | atomic_dec(alloc_workspace); | |
772 | wake_up(workspace_wait); | |
773 | } | |
774 | return workspace; | |
775 | } | |
776 | ||
777 | /* | |
778 | * put a workspace struct back on the list or free it if we have enough | |
779 | * idle ones sitting around | |
780 | */ | |
781 | static void free_workspace(int type, struct list_head *workspace) | |
782 | { | |
783 | int idx = type - 1; | |
784 | struct list_head *idle_workspace = &comp_idle_workspace[idx]; | |
785 | spinlock_t *workspace_lock = &comp_workspace_lock[idx]; | |
786 | atomic_t *alloc_workspace = &comp_alloc_workspace[idx]; | |
787 | wait_queue_head_t *workspace_wait = &comp_workspace_wait[idx]; | |
788 | int *num_workspace = &comp_num_workspace[idx]; | |
789 | ||
790 | spin_lock(workspace_lock); | |
791 | if (*num_workspace < num_online_cpus()) { | |
792 | list_add_tail(workspace, idle_workspace); | |
793 | (*num_workspace)++; | |
794 | spin_unlock(workspace_lock); | |
795 | goto wake; | |
796 | } | |
797 | spin_unlock(workspace_lock); | |
798 | ||
799 | btrfs_compress_op[idx]->free_workspace(workspace); | |
800 | atomic_dec(alloc_workspace); | |
801 | wake: | |
802 | if (waitqueue_active(workspace_wait)) | |
803 | wake_up(workspace_wait); | |
804 | } | |
805 | ||
806 | /* | |
807 | * cleanup function for module exit | |
808 | */ | |
809 | static void free_workspaces(void) | |
810 | { | |
811 | struct list_head *workspace; | |
812 | int i; | |
813 | ||
814 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
815 | while (!list_empty(&comp_idle_workspace[i])) { | |
816 | workspace = comp_idle_workspace[i].next; | |
817 | list_del(workspace); | |
818 | btrfs_compress_op[i]->free_workspace(workspace); | |
819 | atomic_dec(&comp_alloc_workspace[i]); | |
820 | } | |
821 | } | |
822 | } | |
823 | ||
824 | /* | |
825 | * given an address space and start/len, compress the bytes. | |
826 | * | |
827 | * pages are allocated to hold the compressed result and stored | |
828 | * in 'pages' | |
829 | * | |
830 | * out_pages is used to return the number of pages allocated. There | |
831 | * may be pages allocated even if we return an error | |
832 | * | |
833 | * total_in is used to return the number of bytes actually read. It | |
834 | * may be smaller then len if we had to exit early because we | |
835 | * ran out of room in the pages array or because we cross the | |
836 | * max_out threshold. | |
837 | * | |
838 | * total_out is used to return the total number of compressed bytes | |
839 | * | |
840 | * max_out tells us the max number of bytes that we're allowed to | |
841 | * stuff into pages | |
842 | */ | |
843 | int btrfs_compress_pages(int type, struct address_space *mapping, | |
844 | u64 start, unsigned long len, | |
845 | struct page **pages, | |
846 | unsigned long nr_dest_pages, | |
847 | unsigned long *out_pages, | |
848 | unsigned long *total_in, | |
849 | unsigned long *total_out, | |
850 | unsigned long max_out) | |
851 | { | |
852 | struct list_head *workspace; | |
853 | int ret; | |
854 | ||
855 | workspace = find_workspace(type); | |
856 | if (IS_ERR(workspace)) | |
857 | return -1; | |
858 | ||
859 | ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, | |
860 | start, len, pages, | |
861 | nr_dest_pages, out_pages, | |
862 | total_in, total_out, | |
863 | max_out); | |
864 | free_workspace(type, workspace); | |
865 | return ret; | |
866 | } | |
867 | ||
868 | /* | |
869 | * pages_in is an array of pages with compressed data. | |
870 | * | |
871 | * disk_start is the starting logical offset of this array in the file | |
872 | * | |
873 | * bvec is a bio_vec of pages from the file that we want to decompress into | |
874 | * | |
875 | * vcnt is the count of pages in the biovec | |
876 | * | |
877 | * srclen is the number of bytes in pages_in | |
878 | * | |
879 | * The basic idea is that we have a bio that was created by readpages. | |
880 | * The pages in the bio are for the uncompressed data, and they may not | |
881 | * be contiguous. They all correspond to the range of bytes covered by | |
882 | * the compressed extent. | |
883 | */ | |
884 | int btrfs_decompress_biovec(int type, struct page **pages_in, u64 disk_start, | |
885 | struct bio_vec *bvec, int vcnt, size_t srclen) | |
886 | { | |
887 | struct list_head *workspace; | |
888 | int ret; | |
889 | ||
890 | workspace = find_workspace(type); | |
891 | if (IS_ERR(workspace)) | |
892 | return -ENOMEM; | |
893 | ||
894 | ret = btrfs_compress_op[type-1]->decompress_biovec(workspace, pages_in, | |
895 | disk_start, | |
896 | bvec, vcnt, srclen); | |
897 | free_workspace(type, workspace); | |
898 | return ret; | |
899 | } | |
900 | ||
901 | /* | |
902 | * a less complex decompression routine. Our compressed data fits in a | |
903 | * single page, and we want to read a single page out of it. | |
904 | * start_byte tells us the offset into the compressed data we're interested in | |
905 | */ | |
906 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, | |
907 | unsigned long start_byte, size_t srclen, size_t destlen) | |
908 | { | |
909 | struct list_head *workspace; | |
910 | int ret; | |
911 | ||
912 | workspace = find_workspace(type); | |
913 | if (IS_ERR(workspace)) | |
914 | return -ENOMEM; | |
915 | ||
916 | ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, | |
917 | dest_page, start_byte, | |
918 | srclen, destlen); | |
919 | ||
920 | free_workspace(type, workspace); | |
921 | return ret; | |
922 | } | |
923 | ||
8e4eef7a | 924 | void btrfs_exit_compress(void) |
261507a0 LZ |
925 | { |
926 | free_workspaces(); | |
927 | } | |
3a39c18d LZ |
928 | |
929 | /* | |
930 | * Copy uncompressed data from working buffer to pages. | |
931 | * | |
932 | * buf_start is the byte offset we're of the start of our workspace buffer. | |
933 | * | |
934 | * total_out is the last byte of the buffer | |
935 | */ | |
936 | int btrfs_decompress_buf2page(char *buf, unsigned long buf_start, | |
937 | unsigned long total_out, u64 disk_start, | |
938 | struct bio_vec *bvec, int vcnt, | |
939 | unsigned long *page_index, | |
940 | unsigned long *pg_offset) | |
941 | { | |
942 | unsigned long buf_offset; | |
943 | unsigned long current_buf_start; | |
944 | unsigned long start_byte; | |
945 | unsigned long working_bytes = total_out - buf_start; | |
946 | unsigned long bytes; | |
947 | char *kaddr; | |
948 | struct page *page_out = bvec[*page_index].bv_page; | |
949 | ||
950 | /* | |
951 | * start byte is the first byte of the page we're currently | |
952 | * copying into relative to the start of the compressed data. | |
953 | */ | |
954 | start_byte = page_offset(page_out) - disk_start; | |
955 | ||
956 | /* we haven't yet hit data corresponding to this page */ | |
957 | if (total_out <= start_byte) | |
958 | return 1; | |
959 | ||
960 | /* | |
961 | * the start of the data we care about is offset into | |
962 | * the middle of our working buffer | |
963 | */ | |
964 | if (total_out > start_byte && buf_start < start_byte) { | |
965 | buf_offset = start_byte - buf_start; | |
966 | working_bytes -= buf_offset; | |
967 | } else { | |
968 | buf_offset = 0; | |
969 | } | |
970 | current_buf_start = buf_start; | |
971 | ||
972 | /* copy bytes from the working buffer into the pages */ | |
973 | while (working_bytes > 0) { | |
974 | bytes = min(PAGE_CACHE_SIZE - *pg_offset, | |
975 | PAGE_CACHE_SIZE - buf_offset); | |
976 | bytes = min(bytes, working_bytes); | |
977 | kaddr = kmap_atomic(page_out, KM_USER0); | |
978 | memcpy(kaddr + *pg_offset, buf + buf_offset, bytes); | |
979 | kunmap_atomic(kaddr, KM_USER0); | |
980 | flush_dcache_page(page_out); | |
981 | ||
982 | *pg_offset += bytes; | |
983 | buf_offset += bytes; | |
984 | working_bytes -= bytes; | |
985 | current_buf_start += bytes; | |
986 | ||
987 | /* check if we need to pick another page */ | |
988 | if (*pg_offset == PAGE_CACHE_SIZE) { | |
989 | (*page_index)++; | |
990 | if (*page_index >= vcnt) | |
991 | return 0; | |
992 | ||
993 | page_out = bvec[*page_index].bv_page; | |
994 | *pg_offset = 0; | |
995 | start_byte = page_offset(page_out) - disk_start; | |
996 | ||
997 | /* | |
998 | * make sure our new page is covered by this | |
999 | * working buffer | |
1000 | */ | |
1001 | if (total_out <= start_byte) | |
1002 | return 1; | |
1003 | ||
1004 | /* | |
1005 | * the next page in the biovec might not be adjacent | |
1006 | * to the last page, but it might still be found | |
1007 | * inside this working buffer. bump our offset pointer | |
1008 | */ | |
1009 | if (total_out > start_byte && | |
1010 | current_buf_start < start_byte) { | |
1011 | buf_offset = start_byte - buf_start; | |
1012 | working_bytes = total_out - start_byte; | |
1013 | current_buf_start = buf_start + buf_offset; | |
1014 | } | |
1015 | } | |
1016 | } | |
1017 | ||
1018 | return 1; | |
1019 | } |