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c8b97818 CM |
1 | /* |
2 | * Copyright (C) 2008 Oracle. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/bio.h> | |
21 | #include <linux/buffer_head.h> | |
22 | #include <linux/file.h> | |
23 | #include <linux/fs.h> | |
24 | #include <linux/pagemap.h> | |
25 | #include <linux/highmem.h> | |
26 | #include <linux/time.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/string.h> | |
29 | #include <linux/smp_lock.h> | |
30 | #include <linux/backing-dev.h> | |
31 | #include <linux/mpage.h> | |
32 | #include <linux/swap.h> | |
33 | #include <linux/writeback.h> | |
34 | #include <linux/bit_spinlock.h> | |
35 | #include <linux/version.h> | |
771ed689 | 36 | #include <linux/pagevec.h> |
4b4e25f2 | 37 | #include "compat.h" |
c8b97818 CM |
38 | #include "ctree.h" |
39 | #include "disk-io.h" | |
40 | #include "transaction.h" | |
41 | #include "btrfs_inode.h" | |
42 | #include "volumes.h" | |
43 | #include "ordered-data.h" | |
c8b97818 CM |
44 | #include "compression.h" |
45 | #include "extent_io.h" | |
46 | #include "extent_map.h" | |
47 | ||
48 | struct compressed_bio { | |
49 | /* number of bios pending for this compressed extent */ | |
50 | atomic_t pending_bios; | |
51 | ||
52 | /* the pages with the compressed data on them */ | |
53 | struct page **compressed_pages; | |
54 | ||
55 | /* inode that owns this data */ | |
56 | struct inode *inode; | |
57 | ||
58 | /* starting offset in the inode for our pages */ | |
59 | u64 start; | |
60 | ||
61 | /* number of bytes in the inode we're working on */ | |
62 | unsigned long len; | |
63 | ||
64 | /* number of bytes on disk */ | |
65 | unsigned long compressed_len; | |
66 | ||
67 | /* number of compressed pages in the array */ | |
68 | unsigned long nr_pages; | |
69 | ||
70 | /* IO errors */ | |
71 | int errors; | |
d20f7043 | 72 | int mirror_num; |
c8b97818 CM |
73 | |
74 | /* for reads, this is the bio we are copying the data into */ | |
75 | struct bio *orig_bio; | |
d20f7043 CM |
76 | |
77 | /* | |
78 | * the start of a variable length array of checksums only | |
79 | * used by reads | |
80 | */ | |
81 | u32 sums; | |
c8b97818 CM |
82 | }; |
83 | ||
d20f7043 CM |
84 | static inline int compressed_bio_size(struct btrfs_root *root, |
85 | unsigned long disk_size) | |
86 | { | |
87 | u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); | |
88 | return sizeof(struct compressed_bio) + | |
89 | ((disk_size + root->sectorsize - 1) / root->sectorsize) * | |
90 | csum_size; | |
91 | } | |
92 | ||
c8b97818 CM |
93 | static struct bio *compressed_bio_alloc(struct block_device *bdev, |
94 | u64 first_byte, gfp_t gfp_flags) | |
95 | { | |
96 | struct bio *bio; | |
97 | int nr_vecs; | |
98 | ||
99 | nr_vecs = bio_get_nr_vecs(bdev); | |
100 | bio = bio_alloc(gfp_flags, nr_vecs); | |
101 | ||
102 | if (bio == NULL && (current->flags & PF_MEMALLOC)) { | |
103 | while (!bio && (nr_vecs /= 2)) | |
104 | bio = bio_alloc(gfp_flags, nr_vecs); | |
105 | } | |
106 | ||
107 | if (bio) { | |
108 | bio->bi_size = 0; | |
109 | bio->bi_bdev = bdev; | |
110 | bio->bi_sector = first_byte >> 9; | |
111 | } | |
112 | return bio; | |
113 | } | |
114 | ||
d20f7043 CM |
115 | static int check_compressed_csum(struct inode *inode, |
116 | struct compressed_bio *cb, | |
117 | u64 disk_start) | |
118 | { | |
119 | int ret; | |
120 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
121 | struct page *page; | |
122 | unsigned long i; | |
123 | char *kaddr; | |
124 | u32 csum; | |
125 | u32 *cb_sum = &cb->sums; | |
126 | ||
17d217fe | 127 | if (btrfs_test_flag(inode, NODATASUM)) |
d20f7043 CM |
128 | return 0; |
129 | ||
130 | for (i = 0; i < cb->nr_pages; i++) { | |
131 | page = cb->compressed_pages[i]; | |
132 | csum = ~(u32)0; | |
133 | ||
134 | kaddr = kmap_atomic(page, KM_USER0); | |
135 | csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE); | |
136 | btrfs_csum_final(csum, (char *)&csum); | |
137 | kunmap_atomic(kaddr, KM_USER0); | |
138 | ||
139 | if (csum != *cb_sum) { | |
d397712b CM |
140 | printk(KERN_INFO "btrfs csum failed ino %lu " |
141 | "extent %llu csum %u " | |
d20f7043 CM |
142 | "wanted %u mirror %d\n", inode->i_ino, |
143 | (unsigned long long)disk_start, | |
144 | csum, *cb_sum, cb->mirror_num); | |
145 | ret = -EIO; | |
146 | goto fail; | |
147 | } | |
148 | cb_sum++; | |
149 | ||
150 | } | |
151 | ret = 0; | |
152 | fail: | |
153 | return ret; | |
154 | } | |
155 | ||
c8b97818 CM |
156 | /* when we finish reading compressed pages from the disk, we |
157 | * decompress them and then run the bio end_io routines on the | |
158 | * decompressed pages (in the inode address space). | |
159 | * | |
160 | * This allows the checksumming and other IO error handling routines | |
161 | * to work normally | |
162 | * | |
163 | * The compressed pages are freed here, and it must be run | |
164 | * in process context | |
165 | */ | |
166 | static void end_compressed_bio_read(struct bio *bio, int err) | |
167 | { | |
168 | struct extent_io_tree *tree; | |
169 | struct compressed_bio *cb = bio->bi_private; | |
170 | struct inode *inode; | |
171 | struct page *page; | |
172 | unsigned long index; | |
173 | int ret; | |
174 | ||
175 | if (err) | |
176 | cb->errors = 1; | |
177 | ||
178 | /* if there are more bios still pending for this compressed | |
179 | * extent, just exit | |
180 | */ | |
181 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
182 | goto out; | |
183 | ||
d20f7043 CM |
184 | inode = cb->inode; |
185 | ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); | |
186 | if (ret) | |
187 | goto csum_failed; | |
188 | ||
c8b97818 CM |
189 | /* ok, we're the last bio for this extent, lets start |
190 | * the decompression. | |
191 | */ | |
c8b97818 CM |
192 | tree = &BTRFS_I(inode)->io_tree; |
193 | ret = btrfs_zlib_decompress_biovec(cb->compressed_pages, | |
194 | cb->start, | |
195 | cb->orig_bio->bi_io_vec, | |
196 | cb->orig_bio->bi_vcnt, | |
197 | cb->compressed_len); | |
d20f7043 | 198 | csum_failed: |
c8b97818 CM |
199 | if (ret) |
200 | cb->errors = 1; | |
201 | ||
202 | /* release the compressed pages */ | |
203 | index = 0; | |
204 | for (index = 0; index < cb->nr_pages; index++) { | |
205 | page = cb->compressed_pages[index]; | |
206 | page->mapping = NULL; | |
207 | page_cache_release(page); | |
208 | } | |
209 | ||
210 | /* do io completion on the original bio */ | |
771ed689 | 211 | if (cb->errors) { |
c8b97818 | 212 | bio_io_error(cb->orig_bio); |
d20f7043 CM |
213 | } else { |
214 | int bio_index = 0; | |
215 | struct bio_vec *bvec = cb->orig_bio->bi_io_vec; | |
216 | ||
217 | /* | |
218 | * we have verified the checksum already, set page | |
219 | * checked so the end_io handlers know about it | |
220 | */ | |
d397712b | 221 | while (bio_index < cb->orig_bio->bi_vcnt) { |
d20f7043 CM |
222 | SetPageChecked(bvec->bv_page); |
223 | bvec++; | |
224 | bio_index++; | |
225 | } | |
c8b97818 | 226 | bio_endio(cb->orig_bio, 0); |
d20f7043 | 227 | } |
c8b97818 CM |
228 | |
229 | /* finally free the cb struct */ | |
230 | kfree(cb->compressed_pages); | |
231 | kfree(cb); | |
232 | out: | |
233 | bio_put(bio); | |
234 | } | |
235 | ||
236 | /* | |
237 | * Clear the writeback bits on all of the file | |
238 | * pages for a compressed write | |
239 | */ | |
240 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, | |
241 | unsigned long ram_size) | |
242 | { | |
243 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
244 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
245 | struct page *pages[16]; | |
246 | unsigned long nr_pages = end_index - index + 1; | |
247 | int i; | |
248 | int ret; | |
249 | ||
d397712b | 250 | while (nr_pages > 0) { |
c8b97818 | 251 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
252 | min_t(unsigned long, |
253 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
254 | if (ret == 0) { |
255 | nr_pages -= 1; | |
256 | index += 1; | |
257 | continue; | |
258 | } | |
259 | for (i = 0; i < ret; i++) { | |
260 | end_page_writeback(pages[i]); | |
261 | page_cache_release(pages[i]); | |
262 | } | |
263 | nr_pages -= ret; | |
264 | index += ret; | |
265 | } | |
266 | /* the inode may be gone now */ | |
267 | return 0; | |
268 | } | |
269 | ||
270 | /* | |
271 | * do the cleanup once all the compressed pages hit the disk. | |
272 | * This will clear writeback on the file pages and free the compressed | |
273 | * pages. | |
274 | * | |
275 | * This also calls the writeback end hooks for the file pages so that | |
276 | * metadata and checksums can be updated in the file. | |
277 | */ | |
278 | static void end_compressed_bio_write(struct bio *bio, int err) | |
279 | { | |
280 | struct extent_io_tree *tree; | |
281 | struct compressed_bio *cb = bio->bi_private; | |
282 | struct inode *inode; | |
283 | struct page *page; | |
284 | unsigned long index; | |
285 | ||
286 | if (err) | |
287 | cb->errors = 1; | |
288 | ||
289 | /* if there are more bios still pending for this compressed | |
290 | * extent, just exit | |
291 | */ | |
292 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
293 | goto out; | |
294 | ||
295 | /* ok, we're the last bio for this extent, step one is to | |
296 | * call back into the FS and do all the end_io operations | |
297 | */ | |
298 | inode = cb->inode; | |
299 | tree = &BTRFS_I(inode)->io_tree; | |
70b99e69 | 300 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
c8b97818 CM |
301 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
302 | cb->start, | |
303 | cb->start + cb->len - 1, | |
304 | NULL, 1); | |
70b99e69 | 305 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 CM |
306 | |
307 | end_compressed_writeback(inode, cb->start, cb->len); | |
308 | /* note, our inode could be gone now */ | |
309 | ||
310 | /* | |
311 | * release the compressed pages, these came from alloc_page and | |
312 | * are not attached to the inode at all | |
313 | */ | |
314 | index = 0; | |
315 | for (index = 0; index < cb->nr_pages; index++) { | |
316 | page = cb->compressed_pages[index]; | |
317 | page->mapping = NULL; | |
318 | page_cache_release(page); | |
319 | } | |
320 | ||
321 | /* finally free the cb struct */ | |
322 | kfree(cb->compressed_pages); | |
323 | kfree(cb); | |
324 | out: | |
325 | bio_put(bio); | |
326 | } | |
327 | ||
328 | /* | |
329 | * worker function to build and submit bios for previously compressed pages. | |
330 | * The corresponding pages in the inode should be marked for writeback | |
331 | * and the compressed pages should have a reference on them for dropping | |
332 | * when the IO is complete. | |
333 | * | |
334 | * This also checksums the file bytes and gets things ready for | |
335 | * the end io hooks. | |
336 | */ | |
337 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
338 | unsigned long len, u64 disk_start, | |
339 | unsigned long compressed_len, | |
340 | struct page **compressed_pages, | |
341 | unsigned long nr_pages) | |
342 | { | |
343 | struct bio *bio = NULL; | |
344 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
345 | struct compressed_bio *cb; | |
346 | unsigned long bytes_left; | |
347 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
348 | int page_index = 0; | |
349 | struct page *page; | |
350 | u64 first_byte = disk_start; | |
351 | struct block_device *bdev; | |
352 | int ret; | |
353 | ||
354 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
d20f7043 | 355 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); |
c8b97818 CM |
356 | atomic_set(&cb->pending_bios, 0); |
357 | cb->errors = 0; | |
358 | cb->inode = inode; | |
359 | cb->start = start; | |
360 | cb->len = len; | |
d20f7043 | 361 | cb->mirror_num = 0; |
c8b97818 CM |
362 | cb->compressed_pages = compressed_pages; |
363 | cb->compressed_len = compressed_len; | |
364 | cb->orig_bio = NULL; | |
365 | cb->nr_pages = nr_pages; | |
366 | ||
367 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
368 | ||
c8b97818 CM |
369 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
370 | bio->bi_private = cb; | |
371 | bio->bi_end_io = end_compressed_bio_write; | |
372 | atomic_inc(&cb->pending_bios); | |
373 | ||
374 | /* create and submit bios for the compressed pages */ | |
375 | bytes_left = compressed_len; | |
cfbc246e | 376 | for (page_index = 0; page_index < cb->nr_pages; page_index++) { |
c8b97818 CM |
377 | page = compressed_pages[page_index]; |
378 | page->mapping = inode->i_mapping; | |
379 | if (bio->bi_size) | |
380 | ret = io_tree->ops->merge_bio_hook(page, 0, | |
381 | PAGE_CACHE_SIZE, | |
382 | bio, 0); | |
383 | else | |
384 | ret = 0; | |
385 | ||
70b99e69 | 386 | page->mapping = NULL; |
c8b97818 CM |
387 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < |
388 | PAGE_CACHE_SIZE) { | |
389 | bio_get(bio); | |
390 | ||
af09abfe CM |
391 | /* |
392 | * inc the count before we submit the bio so | |
393 | * we know the end IO handler won't happen before | |
394 | * we inc the count. Otherwise, the cb might get | |
395 | * freed before we're done setting it up | |
396 | */ | |
397 | atomic_inc(&cb->pending_bios); | |
c8b97818 CM |
398 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); |
399 | BUG_ON(ret); | |
400 | ||
d20f7043 CM |
401 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
402 | BUG_ON(ret); | |
403 | ||
c8b97818 CM |
404 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
405 | BUG_ON(ret); | |
406 | ||
407 | bio_put(bio); | |
408 | ||
409 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
c8b97818 CM |
410 | bio->bi_private = cb; |
411 | bio->bi_end_io = end_compressed_bio_write; | |
412 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
413 | } | |
cfbc246e CM |
414 | if (bytes_left < PAGE_CACHE_SIZE) { |
415 | printk("bytes left %lu compress len %lu nr %lu\n", | |
416 | bytes_left, cb->compressed_len, cb->nr_pages); | |
417 | } | |
c8b97818 CM |
418 | bytes_left -= PAGE_CACHE_SIZE; |
419 | first_byte += PAGE_CACHE_SIZE; | |
771ed689 | 420 | cond_resched(); |
c8b97818 CM |
421 | } |
422 | bio_get(bio); | |
423 | ||
424 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
425 | BUG_ON(ret); | |
426 | ||
d20f7043 CM |
427 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
428 | BUG_ON(ret); | |
429 | ||
c8b97818 CM |
430 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
431 | BUG_ON(ret); | |
432 | ||
433 | bio_put(bio); | |
434 | return 0; | |
435 | } | |
436 | ||
771ed689 CM |
437 | static 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 page_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 pagevec pvec; | |
451 | struct extent_map_tree *em_tree; | |
452 | struct extent_io_tree *tree; | |
453 | u64 end; | |
454 | int misses = 0; | |
455 | ||
456 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; | |
457 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); | |
458 | em_tree = &BTRFS_I(inode)->extent_tree; | |
459 | tree = &BTRFS_I(inode)->io_tree; | |
460 | ||
461 | if (isize == 0) | |
462 | return 0; | |
463 | ||
464 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; | |
465 | ||
466 | pagevec_init(&pvec, 0); | |
d397712b | 467 | while (last_offset < compressed_end) { |
771ed689 CM |
468 | page_index = last_offset >> PAGE_CACHE_SHIFT; |
469 | ||
470 | if (page_index > end_index) | |
471 | break; | |
472 | ||
473 | rcu_read_lock(); | |
474 | page = radix_tree_lookup(&mapping->page_tree, page_index); | |
475 | rcu_read_unlock(); | |
476 | if (page) { | |
477 | misses++; | |
478 | if (misses > 4) | |
479 | break; | |
480 | goto next; | |
481 | } | |
482 | ||
483 | page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS); | |
484 | if (!page) | |
485 | break; | |
486 | ||
487 | page->index = page_index; | |
488 | /* | |
489 | * what we want to do here is call add_to_page_cache_lru, | |
490 | * but that isn't exported, so we reproduce it here | |
491 | */ | |
492 | if (add_to_page_cache(page, mapping, | |
493 | page->index, GFP_NOFS)) { | |
494 | page_cache_release(page); | |
495 | goto next; | |
496 | } | |
497 | ||
498 | /* open coding of lru_cache_add, also not exported */ | |
499 | page_cache_get(page); | |
500 | if (!pagevec_add(&pvec, page)) | |
15916de8 | 501 | __pagevec_lru_add_file(&pvec); |
771ed689 CM |
502 | |
503 | end = last_offset + PAGE_CACHE_SIZE - 1; | |
504 | /* | |
505 | * at this point, we have a locked page in the page cache | |
506 | * for these bytes in the file. But, we have to make | |
507 | * sure they map to this compressed extent on disk. | |
508 | */ | |
509 | set_page_extent_mapped(page); | |
510 | lock_extent(tree, last_offset, end, GFP_NOFS); | |
511 | spin_lock(&em_tree->lock); | |
512 | em = lookup_extent_mapping(em_tree, last_offset, | |
513 | PAGE_CACHE_SIZE); | |
514 | spin_unlock(&em_tree->lock); | |
515 | ||
516 | if (!em || last_offset < em->start || | |
517 | (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || | |
518 | (em->block_start >> 9) != cb->orig_bio->bi_sector) { | |
519 | free_extent_map(em); | |
520 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
521 | unlock_page(page); | |
522 | page_cache_release(page); | |
523 | break; | |
524 | } | |
525 | free_extent_map(em); | |
526 | ||
527 | if (page->index == end_index) { | |
528 | char *userpage; | |
529 | size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); | |
530 | ||
531 | if (zero_offset) { | |
532 | int zeros; | |
533 | zeros = PAGE_CACHE_SIZE - zero_offset; | |
534 | userpage = kmap_atomic(page, KM_USER0); | |
535 | memset(userpage + zero_offset, 0, zeros); | |
536 | flush_dcache_page(page); | |
537 | kunmap_atomic(userpage, KM_USER0); | |
538 | } | |
539 | } | |
540 | ||
541 | ret = bio_add_page(cb->orig_bio, page, | |
542 | PAGE_CACHE_SIZE, 0); | |
543 | ||
544 | if (ret == PAGE_CACHE_SIZE) { | |
545 | nr_pages++; | |
546 | page_cache_release(page); | |
547 | } else { | |
548 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
549 | unlock_page(page); | |
550 | page_cache_release(page); | |
551 | break; | |
552 | } | |
553 | next: | |
554 | last_offset += PAGE_CACHE_SIZE; | |
555 | } | |
556 | if (pagevec_count(&pvec)) | |
15916de8 | 557 | __pagevec_lru_add_file(&pvec); |
771ed689 CM |
558 | return 0; |
559 | } | |
560 | ||
c8b97818 CM |
561 | /* |
562 | * for a compressed read, the bio we get passed has all the inode pages | |
563 | * in it. We don't actually do IO on those pages but allocate new ones | |
564 | * to hold the compressed pages on disk. | |
565 | * | |
566 | * bio->bi_sector points to the compressed extent on disk | |
567 | * bio->bi_io_vec points to all of the inode pages | |
568 | * bio->bi_vcnt is a count of pages | |
569 | * | |
570 | * After the compressed pages are read, we copy the bytes into the | |
571 | * bio we were passed and then call the bio end_io calls | |
572 | */ | |
573 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
574 | int mirror_num, unsigned long bio_flags) | |
575 | { | |
576 | struct extent_io_tree *tree; | |
577 | struct extent_map_tree *em_tree; | |
578 | struct compressed_bio *cb; | |
579 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
580 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
581 | unsigned long compressed_len; | |
582 | unsigned long nr_pages; | |
583 | unsigned long page_index; | |
584 | struct page *page; | |
585 | struct block_device *bdev; | |
586 | struct bio *comp_bio; | |
587 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; | |
e04ca626 CM |
588 | u64 em_len; |
589 | u64 em_start; | |
c8b97818 CM |
590 | struct extent_map *em; |
591 | int ret; | |
d20f7043 | 592 | u32 *sums; |
c8b97818 CM |
593 | |
594 | tree = &BTRFS_I(inode)->io_tree; | |
595 | em_tree = &BTRFS_I(inode)->extent_tree; | |
596 | ||
597 | /* we need the actual starting offset of this extent in the file */ | |
598 | spin_lock(&em_tree->lock); | |
599 | em = lookup_extent_mapping(em_tree, | |
600 | page_offset(bio->bi_io_vec->bv_page), | |
601 | PAGE_CACHE_SIZE); | |
602 | spin_unlock(&em_tree->lock); | |
603 | ||
d20f7043 CM |
604 | compressed_len = em->block_len; |
605 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); | |
c8b97818 CM |
606 | atomic_set(&cb->pending_bios, 0); |
607 | cb->errors = 0; | |
608 | cb->inode = inode; | |
d20f7043 CM |
609 | cb->mirror_num = mirror_num; |
610 | sums = &cb->sums; | |
c8b97818 | 611 | |
ff5b7ee3 | 612 | cb->start = em->orig_start; |
e04ca626 CM |
613 | em_len = em->len; |
614 | em_start = em->start; | |
d20f7043 | 615 | |
c8b97818 | 616 | free_extent_map(em); |
e04ca626 | 617 | em = NULL; |
c8b97818 CM |
618 | |
619 | cb->len = uncompressed_len; | |
620 | cb->compressed_len = compressed_len; | |
621 | cb->orig_bio = bio; | |
622 | ||
623 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
624 | PAGE_CACHE_SIZE; | |
625 | cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages, | |
626 | GFP_NOFS); | |
627 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
628 | ||
629 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
630 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | | |
631 | __GFP_HIGHMEM); | |
632 | } | |
633 | cb->nr_pages = nr_pages; | |
634 | ||
e04ca626 | 635 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 636 | |
771ed689 CM |
637 | /* include any pages we added in add_ra-bio_pages */ |
638 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
639 | cb->len = uncompressed_len; | |
640 | ||
c8b97818 CM |
641 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
642 | comp_bio->bi_private = cb; | |
643 | comp_bio->bi_end_io = end_compressed_bio_read; | |
644 | atomic_inc(&cb->pending_bios); | |
645 | ||
646 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
647 | page = cb->compressed_pages[page_index]; | |
648 | page->mapping = inode->i_mapping; | |
d20f7043 CM |
649 | page->index = em_start >> PAGE_CACHE_SHIFT; |
650 | ||
c8b97818 CM |
651 | if (comp_bio->bi_size) |
652 | ret = tree->ops->merge_bio_hook(page, 0, | |
653 | PAGE_CACHE_SIZE, | |
654 | comp_bio, 0); | |
655 | else | |
656 | ret = 0; | |
657 | ||
70b99e69 | 658 | page->mapping = NULL; |
c8b97818 CM |
659 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < |
660 | PAGE_CACHE_SIZE) { | |
661 | bio_get(comp_bio); | |
662 | ||
663 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
664 | BUG_ON(ret); | |
665 | ||
af09abfe CM |
666 | /* |
667 | * inc the count before we submit the bio so | |
668 | * we know the end IO handler won't happen before | |
669 | * we inc the count. Otherwise, the cb might get | |
670 | * freed before we're done setting it up | |
671 | */ | |
672 | atomic_inc(&cb->pending_bios); | |
673 | ||
17d217fe | 674 | if (!btrfs_test_flag(inode, NODATASUM)) { |
d20f7043 CM |
675 | btrfs_lookup_bio_sums(root, inode, comp_bio, |
676 | sums); | |
677 | } | |
678 | sums += (comp_bio->bi_size + root->sectorsize - 1) / | |
679 | root->sectorsize; | |
680 | ||
681 | ret = btrfs_map_bio(root, READ, comp_bio, | |
682 | mirror_num, 0); | |
c8b97818 CM |
683 | BUG_ON(ret); |
684 | ||
685 | bio_put(comp_bio); | |
686 | ||
687 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
688 | GFP_NOFS); | |
771ed689 CM |
689 | comp_bio->bi_private = cb; |
690 | comp_bio->bi_end_io = end_compressed_bio_read; | |
691 | ||
692 | bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); | |
c8b97818 CM |
693 | } |
694 | cur_disk_byte += PAGE_CACHE_SIZE; | |
695 | } | |
696 | bio_get(comp_bio); | |
697 | ||
698 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
699 | BUG_ON(ret); | |
700 | ||
d397712b | 701 | if (!btrfs_test_flag(inode, NODATASUM)) |
d20f7043 | 702 | btrfs_lookup_bio_sums(root, inode, comp_bio, sums); |
d20f7043 CM |
703 | |
704 | ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); | |
c8b97818 CM |
705 | BUG_ON(ret); |
706 | ||
707 | bio_put(comp_bio); | |
708 | return 0; | |
709 | } |