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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> | |
771ed689 | 35 | #include <linux/pagevec.h> |
4b4e25f2 | 36 | #include "compat.h" |
c8b97818 CM |
37 | #include "ctree.h" |
38 | #include "disk-io.h" | |
39 | #include "transaction.h" | |
40 | #include "btrfs_inode.h" | |
41 | #include "volumes.h" | |
42 | #include "ordered-data.h" | |
c8b97818 CM |
43 | #include "compression.h" |
44 | #include "extent_io.h" | |
45 | #include "extent_map.h" | |
46 | ||
47 | struct compressed_bio { | |
48 | /* number of bios pending for this compressed extent */ | |
49 | atomic_t pending_bios; | |
50 | ||
51 | /* the pages with the compressed data on them */ | |
52 | struct page **compressed_pages; | |
53 | ||
54 | /* inode that owns this data */ | |
55 | struct inode *inode; | |
56 | ||
57 | /* starting offset in the inode for our pages */ | |
58 | u64 start; | |
59 | ||
60 | /* number of bytes in the inode we're working on */ | |
61 | unsigned long len; | |
62 | ||
63 | /* number of bytes on disk */ | |
64 | unsigned long compressed_len; | |
65 | ||
66 | /* number of compressed pages in the array */ | |
67 | unsigned long nr_pages; | |
68 | ||
69 | /* IO errors */ | |
70 | int errors; | |
d20f7043 | 71 | int mirror_num; |
c8b97818 CM |
72 | |
73 | /* for reads, this is the bio we are copying the data into */ | |
74 | struct bio *orig_bio; | |
d20f7043 CM |
75 | |
76 | /* | |
77 | * the start of a variable length array of checksums only | |
78 | * used by reads | |
79 | */ | |
80 | u32 sums; | |
c8b97818 CM |
81 | }; |
82 | ||
d20f7043 CM |
83 | static inline int compressed_bio_size(struct btrfs_root *root, |
84 | unsigned long disk_size) | |
85 | { | |
86 | u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); | |
87 | return sizeof(struct compressed_bio) + | |
88 | ((disk_size + root->sectorsize - 1) / root->sectorsize) * | |
89 | csum_size; | |
90 | } | |
91 | ||
c8b97818 CM |
92 | static struct bio *compressed_bio_alloc(struct block_device *bdev, |
93 | u64 first_byte, gfp_t gfp_flags) | |
94 | { | |
95 | struct bio *bio; | |
96 | int nr_vecs; | |
97 | ||
98 | nr_vecs = bio_get_nr_vecs(bdev); | |
99 | bio = bio_alloc(gfp_flags, nr_vecs); | |
100 | ||
101 | if (bio == NULL && (current->flags & PF_MEMALLOC)) { | |
102 | while (!bio && (nr_vecs /= 2)) | |
103 | bio = bio_alloc(gfp_flags, nr_vecs); | |
104 | } | |
105 | ||
106 | if (bio) { | |
107 | bio->bi_size = 0; | |
108 | bio->bi_bdev = bdev; | |
109 | bio->bi_sector = first_byte >> 9; | |
110 | } | |
111 | return bio; | |
112 | } | |
113 | ||
d20f7043 CM |
114 | static int check_compressed_csum(struct inode *inode, |
115 | struct compressed_bio *cb, | |
116 | u64 disk_start) | |
117 | { | |
118 | int ret; | |
119 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
120 | struct page *page; | |
121 | unsigned long i; | |
122 | char *kaddr; | |
123 | u32 csum; | |
124 | u32 *cb_sum = &cb->sums; | |
125 | ||
6cbff00f | 126 | if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
127 | return 0; |
128 | ||
129 | for (i = 0; i < cb->nr_pages; i++) { | |
130 | page = cb->compressed_pages[i]; | |
131 | csum = ~(u32)0; | |
132 | ||
133 | kaddr = kmap_atomic(page, KM_USER0); | |
134 | csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE); | |
135 | btrfs_csum_final(csum, (char *)&csum); | |
136 | kunmap_atomic(kaddr, KM_USER0); | |
137 | ||
138 | if (csum != *cb_sum) { | |
d397712b CM |
139 | printk(KERN_INFO "btrfs csum failed ino %lu " |
140 | "extent %llu csum %u " | |
d20f7043 CM |
141 | "wanted %u mirror %d\n", inode->i_ino, |
142 | (unsigned long long)disk_start, | |
143 | csum, *cb_sum, cb->mirror_num); | |
144 | ret = -EIO; | |
145 | goto fail; | |
146 | } | |
147 | cb_sum++; | |
148 | ||
149 | } | |
150 | ret = 0; | |
151 | fail: | |
152 | return ret; | |
153 | } | |
154 | ||
c8b97818 CM |
155 | /* when we finish reading compressed pages from the disk, we |
156 | * decompress them and then run the bio end_io routines on the | |
157 | * decompressed pages (in the inode address space). | |
158 | * | |
159 | * This allows the checksumming and other IO error handling routines | |
160 | * to work normally | |
161 | * | |
162 | * The compressed pages are freed here, and it must be run | |
163 | * in process context | |
164 | */ | |
165 | static void end_compressed_bio_read(struct bio *bio, int err) | |
166 | { | |
167 | struct extent_io_tree *tree; | |
168 | struct compressed_bio *cb = bio->bi_private; | |
169 | struct inode *inode; | |
170 | struct page *page; | |
171 | unsigned long index; | |
172 | int ret; | |
173 | ||
174 | if (err) | |
175 | cb->errors = 1; | |
176 | ||
177 | /* if there are more bios still pending for this compressed | |
178 | * extent, just exit | |
179 | */ | |
180 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
181 | goto out; | |
182 | ||
d20f7043 CM |
183 | inode = cb->inode; |
184 | ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); | |
185 | if (ret) | |
186 | goto csum_failed; | |
187 | ||
c8b97818 CM |
188 | /* ok, we're the last bio for this extent, lets start |
189 | * the decompression. | |
190 | */ | |
c8b97818 CM |
191 | tree = &BTRFS_I(inode)->io_tree; |
192 | ret = btrfs_zlib_decompress_biovec(cb->compressed_pages, | |
193 | cb->start, | |
194 | cb->orig_bio->bi_io_vec, | |
195 | cb->orig_bio->bi_vcnt, | |
196 | cb->compressed_len); | |
d20f7043 | 197 | csum_failed: |
c8b97818 CM |
198 | if (ret) |
199 | cb->errors = 1; | |
200 | ||
201 | /* release the compressed pages */ | |
202 | index = 0; | |
203 | for (index = 0; index < cb->nr_pages; index++) { | |
204 | page = cb->compressed_pages[index]; | |
205 | page->mapping = NULL; | |
206 | page_cache_release(page); | |
207 | } | |
208 | ||
209 | /* do io completion on the original bio */ | |
771ed689 | 210 | if (cb->errors) { |
c8b97818 | 211 | bio_io_error(cb->orig_bio); |
d20f7043 CM |
212 | } else { |
213 | int bio_index = 0; | |
214 | struct bio_vec *bvec = cb->orig_bio->bi_io_vec; | |
215 | ||
216 | /* | |
217 | * we have verified the checksum already, set page | |
218 | * checked so the end_io handlers know about it | |
219 | */ | |
d397712b | 220 | while (bio_index < cb->orig_bio->bi_vcnt) { |
d20f7043 CM |
221 | SetPageChecked(bvec->bv_page); |
222 | bvec++; | |
223 | bio_index++; | |
224 | } | |
c8b97818 | 225 | bio_endio(cb->orig_bio, 0); |
d20f7043 | 226 | } |
c8b97818 CM |
227 | |
228 | /* finally free the cb struct */ | |
229 | kfree(cb->compressed_pages); | |
230 | kfree(cb); | |
231 | out: | |
232 | bio_put(bio); | |
233 | } | |
234 | ||
235 | /* | |
236 | * Clear the writeback bits on all of the file | |
237 | * pages for a compressed write | |
238 | */ | |
239 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, | |
240 | unsigned long ram_size) | |
241 | { | |
242 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
243 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
244 | struct page *pages[16]; | |
245 | unsigned long nr_pages = end_index - index + 1; | |
246 | int i; | |
247 | int ret; | |
248 | ||
d397712b | 249 | while (nr_pages > 0) { |
c8b97818 | 250 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
251 | min_t(unsigned long, |
252 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
253 | if (ret == 0) { |
254 | nr_pages -= 1; | |
255 | index += 1; | |
256 | continue; | |
257 | } | |
258 | for (i = 0; i < ret; i++) { | |
259 | end_page_writeback(pages[i]); | |
260 | page_cache_release(pages[i]); | |
261 | } | |
262 | nr_pages -= ret; | |
263 | index += ret; | |
264 | } | |
265 | /* the inode may be gone now */ | |
266 | return 0; | |
267 | } | |
268 | ||
269 | /* | |
270 | * do the cleanup once all the compressed pages hit the disk. | |
271 | * This will clear writeback on the file pages and free the compressed | |
272 | * pages. | |
273 | * | |
274 | * This also calls the writeback end hooks for the file pages so that | |
275 | * metadata and checksums can be updated in the file. | |
276 | */ | |
277 | static void end_compressed_bio_write(struct bio *bio, int err) | |
278 | { | |
279 | struct extent_io_tree *tree; | |
280 | struct compressed_bio *cb = bio->bi_private; | |
281 | struct inode *inode; | |
282 | struct page *page; | |
283 | unsigned long index; | |
284 | ||
285 | if (err) | |
286 | cb->errors = 1; | |
287 | ||
288 | /* if there are more bios still pending for this compressed | |
289 | * extent, just exit | |
290 | */ | |
291 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
292 | goto out; | |
293 | ||
294 | /* ok, we're the last bio for this extent, step one is to | |
295 | * call back into the FS and do all the end_io operations | |
296 | */ | |
297 | inode = cb->inode; | |
298 | tree = &BTRFS_I(inode)->io_tree; | |
70b99e69 | 299 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
c8b97818 CM |
300 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
301 | cb->start, | |
302 | cb->start + cb->len - 1, | |
303 | NULL, 1); | |
70b99e69 | 304 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 CM |
305 | |
306 | end_compressed_writeback(inode, cb->start, cb->len); | |
307 | /* note, our inode could be gone now */ | |
308 | ||
309 | /* | |
310 | * release the compressed pages, these came from alloc_page and | |
311 | * are not attached to the inode at all | |
312 | */ | |
313 | index = 0; | |
314 | for (index = 0; index < cb->nr_pages; index++) { | |
315 | page = cb->compressed_pages[index]; | |
316 | page->mapping = NULL; | |
317 | page_cache_release(page); | |
318 | } | |
319 | ||
320 | /* finally free the cb struct */ | |
321 | kfree(cb->compressed_pages); | |
322 | kfree(cb); | |
323 | out: | |
324 | bio_put(bio); | |
325 | } | |
326 | ||
327 | /* | |
328 | * worker function to build and submit bios for previously compressed pages. | |
329 | * The corresponding pages in the inode should be marked for writeback | |
330 | * and the compressed pages should have a reference on them for dropping | |
331 | * when the IO is complete. | |
332 | * | |
333 | * This also checksums the file bytes and gets things ready for | |
334 | * the end io hooks. | |
335 | */ | |
336 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
337 | unsigned long len, u64 disk_start, | |
338 | unsigned long compressed_len, | |
339 | struct page **compressed_pages, | |
340 | unsigned long nr_pages) | |
341 | { | |
342 | struct bio *bio = NULL; | |
343 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
344 | struct compressed_bio *cb; | |
345 | unsigned long bytes_left; | |
346 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
347 | int page_index = 0; | |
348 | struct page *page; | |
349 | u64 first_byte = disk_start; | |
350 | struct block_device *bdev; | |
351 | int ret; | |
352 | ||
353 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
d20f7043 | 354 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); |
c8b97818 CM |
355 | atomic_set(&cb->pending_bios, 0); |
356 | cb->errors = 0; | |
357 | cb->inode = inode; | |
358 | cb->start = start; | |
359 | cb->len = len; | |
d20f7043 | 360 | cb->mirror_num = 0; |
c8b97818 CM |
361 | cb->compressed_pages = compressed_pages; |
362 | cb->compressed_len = compressed_len; | |
363 | cb->orig_bio = NULL; | |
364 | cb->nr_pages = nr_pages; | |
365 | ||
366 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
367 | ||
c8b97818 CM |
368 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
369 | bio->bi_private = cb; | |
370 | bio->bi_end_io = end_compressed_bio_write; | |
371 | atomic_inc(&cb->pending_bios); | |
372 | ||
373 | /* create and submit bios for the compressed pages */ | |
374 | bytes_left = compressed_len; | |
cfbc246e | 375 | for (page_index = 0; page_index < cb->nr_pages; page_index++) { |
c8b97818 CM |
376 | page = compressed_pages[page_index]; |
377 | page->mapping = inode->i_mapping; | |
378 | if (bio->bi_size) | |
379 | ret = io_tree->ops->merge_bio_hook(page, 0, | |
380 | PAGE_CACHE_SIZE, | |
381 | bio, 0); | |
382 | else | |
383 | ret = 0; | |
384 | ||
70b99e69 | 385 | page->mapping = NULL; |
c8b97818 CM |
386 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < |
387 | PAGE_CACHE_SIZE) { | |
388 | bio_get(bio); | |
389 | ||
af09abfe CM |
390 | /* |
391 | * inc the count before we submit the bio so | |
392 | * we know the end IO handler won't happen before | |
393 | * we inc the count. Otherwise, the cb might get | |
394 | * freed before we're done setting it up | |
395 | */ | |
396 | atomic_inc(&cb->pending_bios); | |
c8b97818 CM |
397 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); |
398 | BUG_ON(ret); | |
399 | ||
d20f7043 CM |
400 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
401 | BUG_ON(ret); | |
402 | ||
c8b97818 CM |
403 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
404 | BUG_ON(ret); | |
405 | ||
406 | bio_put(bio); | |
407 | ||
408 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
c8b97818 CM |
409 | bio->bi_private = cb; |
410 | bio->bi_end_io = end_compressed_bio_write; | |
411 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
412 | } | |
cfbc246e CM |
413 | if (bytes_left < PAGE_CACHE_SIZE) { |
414 | printk("bytes left %lu compress len %lu nr %lu\n", | |
415 | bytes_left, cb->compressed_len, cb->nr_pages); | |
416 | } | |
c8b97818 CM |
417 | bytes_left -= PAGE_CACHE_SIZE; |
418 | first_byte += PAGE_CACHE_SIZE; | |
771ed689 | 419 | cond_resched(); |
c8b97818 CM |
420 | } |
421 | bio_get(bio); | |
422 | ||
423 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
424 | BUG_ON(ret); | |
425 | ||
d20f7043 CM |
426 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
427 | BUG_ON(ret); | |
428 | ||
c8b97818 CM |
429 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
430 | BUG_ON(ret); | |
431 | ||
432 | bio_put(bio); | |
433 | return 0; | |
434 | } | |
435 | ||
771ed689 CM |
436 | static noinline int add_ra_bio_pages(struct inode *inode, |
437 | u64 compressed_end, | |
438 | struct compressed_bio *cb) | |
439 | { | |
440 | unsigned long end_index; | |
441 | unsigned long page_index; | |
442 | u64 last_offset; | |
443 | u64 isize = i_size_read(inode); | |
444 | int ret; | |
445 | struct page *page; | |
446 | unsigned long nr_pages = 0; | |
447 | struct extent_map *em; | |
448 | struct address_space *mapping = inode->i_mapping; | |
449 | struct pagevec pvec; | |
450 | struct extent_map_tree *em_tree; | |
451 | struct extent_io_tree *tree; | |
452 | u64 end; | |
453 | int misses = 0; | |
454 | ||
455 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; | |
456 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); | |
457 | em_tree = &BTRFS_I(inode)->extent_tree; | |
458 | tree = &BTRFS_I(inode)->io_tree; | |
459 | ||
460 | if (isize == 0) | |
461 | return 0; | |
462 | ||
463 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; | |
464 | ||
465 | pagevec_init(&pvec, 0); | |
d397712b | 466 | while (last_offset < compressed_end) { |
771ed689 CM |
467 | page_index = last_offset >> PAGE_CACHE_SHIFT; |
468 | ||
469 | if (page_index > end_index) | |
470 | break; | |
471 | ||
472 | rcu_read_lock(); | |
473 | page = radix_tree_lookup(&mapping->page_tree, page_index); | |
474 | rcu_read_unlock(); | |
475 | if (page) { | |
476 | misses++; | |
477 | if (misses > 4) | |
478 | break; | |
479 | goto next; | |
480 | } | |
481 | ||
482 | page = alloc_page(mapping_gfp_mask(mapping) | GFP_NOFS); | |
483 | if (!page) | |
484 | break; | |
485 | ||
486 | page->index = page_index; | |
487 | /* | |
488 | * what we want to do here is call add_to_page_cache_lru, | |
489 | * but that isn't exported, so we reproduce it here | |
490 | */ | |
491 | if (add_to_page_cache(page, mapping, | |
492 | page->index, GFP_NOFS)) { | |
493 | page_cache_release(page); | |
494 | goto next; | |
495 | } | |
496 | ||
497 | /* open coding of lru_cache_add, also not exported */ | |
498 | page_cache_get(page); | |
499 | if (!pagevec_add(&pvec, page)) | |
15916de8 | 500 | __pagevec_lru_add_file(&pvec); |
771ed689 CM |
501 | |
502 | end = last_offset + PAGE_CACHE_SIZE - 1; | |
503 | /* | |
504 | * at this point, we have a locked page in the page cache | |
505 | * for these bytes in the file. But, we have to make | |
506 | * sure they map to this compressed extent on disk. | |
507 | */ | |
508 | set_page_extent_mapped(page); | |
509 | lock_extent(tree, last_offset, end, GFP_NOFS); | |
510 | spin_lock(&em_tree->lock); | |
511 | em = lookup_extent_mapping(em_tree, last_offset, | |
512 | PAGE_CACHE_SIZE); | |
513 | spin_unlock(&em_tree->lock); | |
514 | ||
515 | if (!em || last_offset < em->start || | |
516 | (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || | |
517 | (em->block_start >> 9) != cb->orig_bio->bi_sector) { | |
518 | free_extent_map(em); | |
519 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
520 | unlock_page(page); | |
521 | page_cache_release(page); | |
522 | break; | |
523 | } | |
524 | free_extent_map(em); | |
525 | ||
526 | if (page->index == end_index) { | |
527 | char *userpage; | |
528 | size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); | |
529 | ||
530 | if (zero_offset) { | |
531 | int zeros; | |
532 | zeros = PAGE_CACHE_SIZE - zero_offset; | |
533 | userpage = kmap_atomic(page, KM_USER0); | |
534 | memset(userpage + zero_offset, 0, zeros); | |
535 | flush_dcache_page(page); | |
536 | kunmap_atomic(userpage, KM_USER0); | |
537 | } | |
538 | } | |
539 | ||
540 | ret = bio_add_page(cb->orig_bio, page, | |
541 | PAGE_CACHE_SIZE, 0); | |
542 | ||
543 | if (ret == PAGE_CACHE_SIZE) { | |
544 | nr_pages++; | |
545 | page_cache_release(page); | |
546 | } else { | |
547 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
548 | unlock_page(page); | |
549 | page_cache_release(page); | |
550 | break; | |
551 | } | |
552 | next: | |
553 | last_offset += PAGE_CACHE_SIZE; | |
554 | } | |
555 | if (pagevec_count(&pvec)) | |
15916de8 | 556 | __pagevec_lru_add_file(&pvec); |
771ed689 CM |
557 | return 0; |
558 | } | |
559 | ||
c8b97818 CM |
560 | /* |
561 | * for a compressed read, the bio we get passed has all the inode pages | |
562 | * in it. We don't actually do IO on those pages but allocate new ones | |
563 | * to hold the compressed pages on disk. | |
564 | * | |
565 | * bio->bi_sector points to the compressed extent on disk | |
566 | * bio->bi_io_vec points to all of the inode pages | |
567 | * bio->bi_vcnt is a count of pages | |
568 | * | |
569 | * After the compressed pages are read, we copy the bytes into the | |
570 | * bio we were passed and then call the bio end_io calls | |
571 | */ | |
572 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
573 | int mirror_num, unsigned long bio_flags) | |
574 | { | |
575 | struct extent_io_tree *tree; | |
576 | struct extent_map_tree *em_tree; | |
577 | struct compressed_bio *cb; | |
578 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
579 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
580 | unsigned long compressed_len; | |
581 | unsigned long nr_pages; | |
582 | unsigned long page_index; | |
583 | struct page *page; | |
584 | struct block_device *bdev; | |
585 | struct bio *comp_bio; | |
586 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; | |
e04ca626 CM |
587 | u64 em_len; |
588 | u64 em_start; | |
c8b97818 CM |
589 | struct extent_map *em; |
590 | int ret; | |
d20f7043 | 591 | u32 *sums; |
c8b97818 CM |
592 | |
593 | tree = &BTRFS_I(inode)->io_tree; | |
594 | em_tree = &BTRFS_I(inode)->extent_tree; | |
595 | ||
596 | /* we need the actual starting offset of this extent in the file */ | |
597 | spin_lock(&em_tree->lock); | |
598 | em = lookup_extent_mapping(em_tree, | |
599 | page_offset(bio->bi_io_vec->bv_page), | |
600 | PAGE_CACHE_SIZE); | |
601 | spin_unlock(&em_tree->lock); | |
602 | ||
d20f7043 CM |
603 | compressed_len = em->block_len; |
604 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); | |
c8b97818 CM |
605 | atomic_set(&cb->pending_bios, 0); |
606 | cb->errors = 0; | |
607 | cb->inode = inode; | |
d20f7043 CM |
608 | cb->mirror_num = mirror_num; |
609 | sums = &cb->sums; | |
c8b97818 | 610 | |
ff5b7ee3 | 611 | cb->start = em->orig_start; |
e04ca626 CM |
612 | em_len = em->len; |
613 | em_start = em->start; | |
d20f7043 | 614 | |
c8b97818 | 615 | free_extent_map(em); |
e04ca626 | 616 | em = NULL; |
c8b97818 CM |
617 | |
618 | cb->len = uncompressed_len; | |
619 | cb->compressed_len = compressed_len; | |
620 | cb->orig_bio = bio; | |
621 | ||
622 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
623 | PAGE_CACHE_SIZE; | |
624 | cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages, | |
625 | GFP_NOFS); | |
626 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
627 | ||
628 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
629 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | | |
630 | __GFP_HIGHMEM); | |
631 | } | |
632 | cb->nr_pages = nr_pages; | |
633 | ||
e04ca626 | 634 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 635 | |
771ed689 CM |
636 | /* include any pages we added in add_ra-bio_pages */ |
637 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
638 | cb->len = uncompressed_len; | |
639 | ||
c8b97818 CM |
640 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
641 | comp_bio->bi_private = cb; | |
642 | comp_bio->bi_end_io = end_compressed_bio_read; | |
643 | atomic_inc(&cb->pending_bios); | |
644 | ||
645 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
646 | page = cb->compressed_pages[page_index]; | |
647 | page->mapping = inode->i_mapping; | |
d20f7043 CM |
648 | page->index = em_start >> PAGE_CACHE_SHIFT; |
649 | ||
c8b97818 CM |
650 | if (comp_bio->bi_size) |
651 | ret = tree->ops->merge_bio_hook(page, 0, | |
652 | PAGE_CACHE_SIZE, | |
653 | comp_bio, 0); | |
654 | else | |
655 | ret = 0; | |
656 | ||
70b99e69 | 657 | page->mapping = NULL; |
c8b97818 CM |
658 | if (ret || bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0) < |
659 | PAGE_CACHE_SIZE) { | |
660 | bio_get(comp_bio); | |
661 | ||
662 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
663 | BUG_ON(ret); | |
664 | ||
af09abfe CM |
665 | /* |
666 | * inc the count before we submit the bio so | |
667 | * we know the end IO handler won't happen before | |
668 | * we inc the count. Otherwise, the cb might get | |
669 | * freed before we're done setting it up | |
670 | */ | |
671 | atomic_inc(&cb->pending_bios); | |
672 | ||
6cbff00f | 673 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
d20f7043 CM |
674 | btrfs_lookup_bio_sums(root, inode, comp_bio, |
675 | sums); | |
676 | } | |
677 | sums += (comp_bio->bi_size + root->sectorsize - 1) / | |
678 | root->sectorsize; | |
679 | ||
680 | ret = btrfs_map_bio(root, READ, comp_bio, | |
681 | mirror_num, 0); | |
c8b97818 CM |
682 | BUG_ON(ret); |
683 | ||
684 | bio_put(comp_bio); | |
685 | ||
686 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
687 | GFP_NOFS); | |
771ed689 CM |
688 | comp_bio->bi_private = cb; |
689 | comp_bio->bi_end_io = end_compressed_bio_read; | |
690 | ||
691 | bio_add_page(comp_bio, page, PAGE_CACHE_SIZE, 0); | |
c8b97818 CM |
692 | } |
693 | cur_disk_byte += PAGE_CACHE_SIZE; | |
694 | } | |
695 | bio_get(comp_bio); | |
696 | ||
697 | ret = btrfs_bio_wq_end_io(root->fs_info, comp_bio, 0); | |
698 | BUG_ON(ret); | |
699 | ||
6cbff00f | 700 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) |
d20f7043 | 701 | btrfs_lookup_bio_sums(root, inode, comp_bio, sums); |
d20f7043 CM |
702 | |
703 | ret = btrfs_map_bio(root, READ, comp_bio, mirror_num, 0); | |
c8b97818 CM |
704 | BUG_ON(ret); |
705 | ||
706 | bio_put(comp_bio); | |
707 | return 0; | |
708 | } |