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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 | ||
65 | /* number of compressed pages in the array */ | |
66 | unsigned long nr_pages; | |
67 | ||
68 | /* IO errors */ | |
69 | int errors; | |
d20f7043 | 70 | int mirror_num; |
c8b97818 CM |
71 | |
72 | /* for reads, this is the bio we are copying the data into */ | |
73 | struct bio *orig_bio; | |
d20f7043 CM |
74 | |
75 | /* | |
76 | * the start of a variable length array of checksums only | |
77 | * used by reads | |
78 | */ | |
79 | u32 sums; | |
c8b97818 CM |
80 | }; |
81 | ||
d20f7043 CM |
82 | static inline int compressed_bio_size(struct btrfs_root *root, |
83 | unsigned long disk_size) | |
84 | { | |
85 | u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); | |
86 | return sizeof(struct compressed_bio) + | |
87 | ((disk_size + root->sectorsize - 1) / root->sectorsize) * | |
88 | csum_size; | |
89 | } | |
90 | ||
c8b97818 CM |
91 | static struct bio *compressed_bio_alloc(struct block_device *bdev, |
92 | u64 first_byte, gfp_t gfp_flags) | |
93 | { | |
94 | struct bio *bio; | |
95 | int nr_vecs; | |
96 | ||
97 | nr_vecs = bio_get_nr_vecs(bdev); | |
98 | bio = bio_alloc(gfp_flags, nr_vecs); | |
99 | ||
100 | if (bio == NULL && (current->flags & PF_MEMALLOC)) { | |
101 | while (!bio && (nr_vecs /= 2)) | |
102 | bio = bio_alloc(gfp_flags, nr_vecs); | |
103 | } | |
104 | ||
105 | if (bio) { | |
106 | bio->bi_size = 0; | |
107 | bio->bi_bdev = bdev; | |
108 | bio->bi_sector = first_byte >> 9; | |
109 | } | |
110 | return bio; | |
111 | } | |
112 | ||
d20f7043 CM |
113 | static int check_compressed_csum(struct inode *inode, |
114 | struct compressed_bio *cb, | |
115 | u64 disk_start) | |
116 | { | |
117 | int ret; | |
118 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
119 | struct page *page; | |
120 | unsigned long i; | |
121 | char *kaddr; | |
122 | u32 csum; | |
123 | u32 *cb_sum = &cb->sums; | |
124 | ||
6cbff00f | 125 | if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
126 | return 0; |
127 | ||
128 | for (i = 0; i < cb->nr_pages; i++) { | |
129 | page = cb->compressed_pages[i]; | |
130 | csum = ~(u32)0; | |
131 | ||
132 | kaddr = kmap_atomic(page, KM_USER0); | |
133 | csum = btrfs_csum_data(root, kaddr, csum, PAGE_CACHE_SIZE); | |
134 | btrfs_csum_final(csum, (char *)&csum); | |
135 | kunmap_atomic(kaddr, KM_USER0); | |
136 | ||
137 | if (csum != *cb_sum) { | |
d397712b CM |
138 | printk(KERN_INFO "btrfs csum failed ino %lu " |
139 | "extent %llu csum %u " | |
d20f7043 CM |
140 | "wanted %u mirror %d\n", inode->i_ino, |
141 | (unsigned long long)disk_start, | |
142 | csum, *cb_sum, cb->mirror_num); | |
143 | ret = -EIO; | |
144 | goto fail; | |
145 | } | |
146 | cb_sum++; | |
147 | ||
148 | } | |
149 | ret = 0; | |
150 | fail: | |
151 | return ret; | |
152 | } | |
153 | ||
c8b97818 CM |
154 | /* when we finish reading compressed pages from the disk, we |
155 | * decompress them and then run the bio end_io routines on the | |
156 | * decompressed pages (in the inode address space). | |
157 | * | |
158 | * This allows the checksumming and other IO error handling routines | |
159 | * to work normally | |
160 | * | |
161 | * The compressed pages are freed here, and it must be run | |
162 | * in process context | |
163 | */ | |
164 | static void end_compressed_bio_read(struct bio *bio, int err) | |
165 | { | |
166 | struct extent_io_tree *tree; | |
167 | struct compressed_bio *cb = bio->bi_private; | |
168 | struct inode *inode; | |
169 | struct page *page; | |
170 | unsigned long index; | |
171 | int ret; | |
172 | ||
173 | if (err) | |
174 | cb->errors = 1; | |
175 | ||
176 | /* if there are more bios still pending for this compressed | |
177 | * extent, just exit | |
178 | */ | |
179 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
180 | goto out; | |
181 | ||
d20f7043 CM |
182 | inode = cb->inode; |
183 | ret = check_compressed_csum(inode, cb, (u64)bio->bi_sector << 9); | |
184 | if (ret) | |
185 | goto csum_failed; | |
186 | ||
c8b97818 CM |
187 | /* ok, we're the last bio for this extent, lets start |
188 | * the decompression. | |
189 | */ | |
c8b97818 CM |
190 | tree = &BTRFS_I(inode)->io_tree; |
191 | ret = btrfs_zlib_decompress_biovec(cb->compressed_pages, | |
192 | cb->start, | |
193 | cb->orig_bio->bi_io_vec, | |
194 | cb->orig_bio->bi_vcnt, | |
195 | cb->compressed_len); | |
d20f7043 | 196 | csum_failed: |
c8b97818 CM |
197 | if (ret) |
198 | cb->errors = 1; | |
199 | ||
200 | /* release the compressed pages */ | |
201 | index = 0; | |
202 | for (index = 0; index < cb->nr_pages; index++) { | |
203 | page = cb->compressed_pages[index]; | |
204 | page->mapping = NULL; | |
205 | page_cache_release(page); | |
206 | } | |
207 | ||
208 | /* do io completion on the original bio */ | |
771ed689 | 209 | if (cb->errors) { |
c8b97818 | 210 | bio_io_error(cb->orig_bio); |
d20f7043 CM |
211 | } else { |
212 | int bio_index = 0; | |
213 | struct bio_vec *bvec = cb->orig_bio->bi_io_vec; | |
214 | ||
215 | /* | |
216 | * we have verified the checksum already, set page | |
217 | * checked so the end_io handlers know about it | |
218 | */ | |
d397712b | 219 | while (bio_index < cb->orig_bio->bi_vcnt) { |
d20f7043 CM |
220 | SetPageChecked(bvec->bv_page); |
221 | bvec++; | |
222 | bio_index++; | |
223 | } | |
c8b97818 | 224 | bio_endio(cb->orig_bio, 0); |
d20f7043 | 225 | } |
c8b97818 CM |
226 | |
227 | /* finally free the cb struct */ | |
228 | kfree(cb->compressed_pages); | |
229 | kfree(cb); | |
230 | out: | |
231 | bio_put(bio); | |
232 | } | |
233 | ||
234 | /* | |
235 | * Clear the writeback bits on all of the file | |
236 | * pages for a compressed write | |
237 | */ | |
238 | static noinline int end_compressed_writeback(struct inode *inode, u64 start, | |
239 | unsigned long ram_size) | |
240 | { | |
241 | unsigned long index = start >> PAGE_CACHE_SHIFT; | |
242 | unsigned long end_index = (start + ram_size - 1) >> PAGE_CACHE_SHIFT; | |
243 | struct page *pages[16]; | |
244 | unsigned long nr_pages = end_index - index + 1; | |
245 | int i; | |
246 | int ret; | |
247 | ||
d397712b | 248 | while (nr_pages > 0) { |
c8b97818 | 249 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
250 | min_t(unsigned long, |
251 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
252 | if (ret == 0) { |
253 | nr_pages -= 1; | |
254 | index += 1; | |
255 | continue; | |
256 | } | |
257 | for (i = 0; i < ret; i++) { | |
258 | end_page_writeback(pages[i]); | |
259 | page_cache_release(pages[i]); | |
260 | } | |
261 | nr_pages -= ret; | |
262 | index += ret; | |
263 | } | |
264 | /* the inode may be gone now */ | |
265 | return 0; | |
266 | } | |
267 | ||
268 | /* | |
269 | * do the cleanup once all the compressed pages hit the disk. | |
270 | * This will clear writeback on the file pages and free the compressed | |
271 | * pages. | |
272 | * | |
273 | * This also calls the writeback end hooks for the file pages so that | |
274 | * metadata and checksums can be updated in the file. | |
275 | */ | |
276 | static void end_compressed_bio_write(struct bio *bio, int err) | |
277 | { | |
278 | struct extent_io_tree *tree; | |
279 | struct compressed_bio *cb = bio->bi_private; | |
280 | struct inode *inode; | |
281 | struct page *page; | |
282 | unsigned long index; | |
283 | ||
284 | if (err) | |
285 | cb->errors = 1; | |
286 | ||
287 | /* if there are more bios still pending for this compressed | |
288 | * extent, just exit | |
289 | */ | |
290 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
291 | goto out; | |
292 | ||
293 | /* ok, we're the last bio for this extent, step one is to | |
294 | * call back into the FS and do all the end_io operations | |
295 | */ | |
296 | inode = cb->inode; | |
297 | tree = &BTRFS_I(inode)->io_tree; | |
70b99e69 | 298 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
c8b97818 CM |
299 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
300 | cb->start, | |
301 | cb->start + cb->len - 1, | |
302 | NULL, 1); | |
70b99e69 | 303 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 CM |
304 | |
305 | end_compressed_writeback(inode, cb->start, cb->len); | |
306 | /* note, our inode could be gone now */ | |
307 | ||
308 | /* | |
309 | * release the compressed pages, these came from alloc_page and | |
310 | * are not attached to the inode at all | |
311 | */ | |
312 | index = 0; | |
313 | for (index = 0; index < cb->nr_pages; index++) { | |
314 | page = cb->compressed_pages[index]; | |
315 | page->mapping = NULL; | |
316 | page_cache_release(page); | |
317 | } | |
318 | ||
319 | /* finally free the cb struct */ | |
320 | kfree(cb->compressed_pages); | |
321 | kfree(cb); | |
322 | out: | |
323 | bio_put(bio); | |
324 | } | |
325 | ||
326 | /* | |
327 | * worker function to build and submit bios for previously compressed pages. | |
328 | * The corresponding pages in the inode should be marked for writeback | |
329 | * and the compressed pages should have a reference on them for dropping | |
330 | * when the IO is complete. | |
331 | * | |
332 | * This also checksums the file bytes and gets things ready for | |
333 | * the end io hooks. | |
334 | */ | |
335 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
336 | unsigned long len, u64 disk_start, | |
337 | unsigned long compressed_len, | |
338 | struct page **compressed_pages, | |
339 | unsigned long nr_pages) | |
340 | { | |
341 | struct bio *bio = NULL; | |
342 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
343 | struct compressed_bio *cb; | |
344 | unsigned long bytes_left; | |
345 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
346 | int page_index = 0; | |
347 | struct page *page; | |
348 | u64 first_byte = disk_start; | |
349 | struct block_device *bdev; | |
350 | int ret; | |
351 | ||
352 | WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1)); | |
d20f7043 | 353 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); |
c8b97818 CM |
354 | atomic_set(&cb->pending_bios, 0); |
355 | cb->errors = 0; | |
356 | cb->inode = inode; | |
357 | cb->start = start; | |
358 | cb->len = len; | |
d20f7043 | 359 | cb->mirror_num = 0; |
c8b97818 CM |
360 | cb->compressed_pages = compressed_pages; |
361 | cb->compressed_len = compressed_len; | |
362 | cb->orig_bio = NULL; | |
363 | cb->nr_pages = nr_pages; | |
364 | ||
365 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
366 | ||
c8b97818 CM |
367 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
368 | bio->bi_private = cb; | |
369 | bio->bi_end_io = end_compressed_bio_write; | |
370 | atomic_inc(&cb->pending_bios); | |
371 | ||
372 | /* create and submit bios for the compressed pages */ | |
373 | bytes_left = compressed_len; | |
cfbc246e | 374 | for (page_index = 0; page_index < cb->nr_pages; page_index++) { |
c8b97818 CM |
375 | page = compressed_pages[page_index]; |
376 | page->mapping = inode->i_mapping; | |
377 | if (bio->bi_size) | |
378 | ret = io_tree->ops->merge_bio_hook(page, 0, | |
379 | PAGE_CACHE_SIZE, | |
380 | bio, 0); | |
381 | else | |
382 | ret = 0; | |
383 | ||
70b99e69 | 384 | page->mapping = NULL; |
c8b97818 CM |
385 | if (ret || bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < |
386 | PAGE_CACHE_SIZE) { | |
387 | bio_get(bio); | |
388 | ||
af09abfe CM |
389 | /* |
390 | * inc the count before we submit the bio so | |
391 | * we know the end IO handler won't happen before | |
392 | * we inc the count. Otherwise, the cb might get | |
393 | * freed before we're done setting it up | |
394 | */ | |
395 | atomic_inc(&cb->pending_bios); | |
c8b97818 CM |
396 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); |
397 | BUG_ON(ret); | |
398 | ||
d20f7043 CM |
399 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
400 | BUG_ON(ret); | |
401 | ||
c8b97818 CM |
402 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
403 | BUG_ON(ret); | |
404 | ||
405 | bio_put(bio); | |
406 | ||
407 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
c8b97818 CM |
408 | bio->bi_private = cb; |
409 | bio->bi_end_io = end_compressed_bio_write; | |
410 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
411 | } | |
cfbc246e CM |
412 | if (bytes_left < PAGE_CACHE_SIZE) { |
413 | printk("bytes left %lu compress len %lu nr %lu\n", | |
414 | bytes_left, cb->compressed_len, cb->nr_pages); | |
415 | } | |
c8b97818 CM |
416 | bytes_left -= PAGE_CACHE_SIZE; |
417 | first_byte += PAGE_CACHE_SIZE; | |
771ed689 | 418 | cond_resched(); |
c8b97818 CM |
419 | } |
420 | bio_get(bio); | |
421 | ||
422 | ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0); | |
423 | BUG_ON(ret); | |
424 | ||
d20f7043 CM |
425 | ret = btrfs_csum_one_bio(root, inode, bio, start, 1); |
426 | BUG_ON(ret); | |
427 | ||
c8b97818 CM |
428 | ret = btrfs_map_bio(root, WRITE, bio, 0, 1); |
429 | BUG_ON(ret); | |
430 | ||
431 | bio_put(bio); | |
432 | return 0; | |
433 | } | |
434 | ||
771ed689 CM |
435 | static noinline int add_ra_bio_pages(struct inode *inode, |
436 | u64 compressed_end, | |
437 | struct compressed_bio *cb) | |
438 | { | |
439 | unsigned long end_index; | |
440 | unsigned long page_index; | |
441 | u64 last_offset; | |
442 | u64 isize = i_size_read(inode); | |
443 | int ret; | |
444 | struct page *page; | |
445 | unsigned long nr_pages = 0; | |
446 | struct extent_map *em; | |
447 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
448 | struct extent_map_tree *em_tree; |
449 | struct extent_io_tree *tree; | |
450 | u64 end; | |
451 | int misses = 0; | |
452 | ||
453 | page = cb->orig_bio->bi_io_vec[cb->orig_bio->bi_vcnt - 1].bv_page; | |
454 | last_offset = (page_offset(page) + PAGE_CACHE_SIZE); | |
455 | em_tree = &BTRFS_I(inode)->extent_tree; | |
456 | tree = &BTRFS_I(inode)->io_tree; | |
457 | ||
458 | if (isize == 0) | |
459 | return 0; | |
460 | ||
461 | end_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT; | |
462 | ||
d397712b | 463 | while (last_offset < compressed_end) { |
771ed689 CM |
464 | page_index = last_offset >> PAGE_CACHE_SHIFT; |
465 | ||
466 | if (page_index > end_index) | |
467 | break; | |
468 | ||
469 | rcu_read_lock(); | |
470 | page = radix_tree_lookup(&mapping->page_tree, page_index); | |
471 | rcu_read_unlock(); | |
472 | if (page) { | |
473 | misses++; | |
474 | if (misses > 4) | |
475 | break; | |
476 | goto next; | |
477 | } | |
478 | ||
28ecb609 NP |
479 | page = __page_cache_alloc(mapping_gfp_mask(mapping) & |
480 | ~__GFP_FS); | |
771ed689 CM |
481 | if (!page) |
482 | break; | |
483 | ||
28ecb609 NP |
484 | if (add_to_page_cache_lru(page, mapping, page_index, |
485 | GFP_NOFS)) { | |
771ed689 CM |
486 | page_cache_release(page); |
487 | goto next; | |
488 | } | |
489 | ||
771ed689 CM |
490 | end = last_offset + PAGE_CACHE_SIZE - 1; |
491 | /* | |
492 | * at this point, we have a locked page in the page cache | |
493 | * for these bytes in the file. But, we have to make | |
494 | * sure they map to this compressed extent on disk. | |
495 | */ | |
496 | set_page_extent_mapped(page); | |
497 | lock_extent(tree, last_offset, end, GFP_NOFS); | |
890871be | 498 | read_lock(&em_tree->lock); |
771ed689 CM |
499 | em = lookup_extent_mapping(em_tree, last_offset, |
500 | PAGE_CACHE_SIZE); | |
890871be | 501 | read_unlock(&em_tree->lock); |
771ed689 CM |
502 | |
503 | if (!em || last_offset < em->start || | |
504 | (last_offset + PAGE_CACHE_SIZE > extent_map_end(em)) || | |
505 | (em->block_start >> 9) != cb->orig_bio->bi_sector) { | |
506 | free_extent_map(em); | |
507 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
508 | unlock_page(page); | |
509 | page_cache_release(page); | |
510 | break; | |
511 | } | |
512 | free_extent_map(em); | |
513 | ||
514 | if (page->index == end_index) { | |
515 | char *userpage; | |
516 | size_t zero_offset = isize & (PAGE_CACHE_SIZE - 1); | |
517 | ||
518 | if (zero_offset) { | |
519 | int zeros; | |
520 | zeros = PAGE_CACHE_SIZE - zero_offset; | |
521 | userpage = kmap_atomic(page, KM_USER0); | |
522 | memset(userpage + zero_offset, 0, zeros); | |
523 | flush_dcache_page(page); | |
524 | kunmap_atomic(userpage, KM_USER0); | |
525 | } | |
526 | } | |
527 | ||
528 | ret = bio_add_page(cb->orig_bio, page, | |
529 | PAGE_CACHE_SIZE, 0); | |
530 | ||
531 | if (ret == PAGE_CACHE_SIZE) { | |
532 | nr_pages++; | |
533 | page_cache_release(page); | |
534 | } else { | |
535 | unlock_extent(tree, last_offset, end, GFP_NOFS); | |
536 | unlock_page(page); | |
537 | page_cache_release(page); | |
538 | break; | |
539 | } | |
540 | next: | |
541 | last_offset += PAGE_CACHE_SIZE; | |
542 | } | |
771ed689 CM |
543 | return 0; |
544 | } | |
545 | ||
c8b97818 CM |
546 | /* |
547 | * for a compressed read, the bio we get passed has all the inode pages | |
548 | * in it. We don't actually do IO on those pages but allocate new ones | |
549 | * to hold the compressed pages on disk. | |
550 | * | |
551 | * bio->bi_sector points to the compressed extent on disk | |
552 | * bio->bi_io_vec points to all of the inode pages | |
553 | * bio->bi_vcnt is a count of pages | |
554 | * | |
555 | * After the compressed pages are read, we copy the bytes into the | |
556 | * bio we were passed and then call the bio end_io calls | |
557 | */ | |
558 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
559 | int mirror_num, unsigned long bio_flags) | |
560 | { | |
561 | struct extent_io_tree *tree; | |
562 | struct extent_map_tree *em_tree; | |
563 | struct compressed_bio *cb; | |
564 | struct btrfs_root *root = BTRFS_I(inode)->root; | |
565 | unsigned long uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
566 | unsigned long compressed_len; | |
567 | unsigned long nr_pages; | |
568 | unsigned long page_index; | |
569 | struct page *page; | |
570 | struct block_device *bdev; | |
571 | struct bio *comp_bio; | |
572 | u64 cur_disk_byte = (u64)bio->bi_sector << 9; | |
e04ca626 CM |
573 | u64 em_len; |
574 | u64 em_start; | |
c8b97818 CM |
575 | struct extent_map *em; |
576 | int ret; | |
d20f7043 | 577 | u32 *sums; |
c8b97818 CM |
578 | |
579 | tree = &BTRFS_I(inode)->io_tree; | |
580 | em_tree = &BTRFS_I(inode)->extent_tree; | |
581 | ||
582 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 583 | read_lock(&em_tree->lock); |
c8b97818 CM |
584 | em = lookup_extent_mapping(em_tree, |
585 | page_offset(bio->bi_io_vec->bv_page), | |
586 | PAGE_CACHE_SIZE); | |
890871be | 587 | read_unlock(&em_tree->lock); |
c8b97818 | 588 | |
d20f7043 CM |
589 | compressed_len = em->block_len; |
590 | cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS); | |
c8b97818 CM |
591 | atomic_set(&cb->pending_bios, 0); |
592 | cb->errors = 0; | |
593 | cb->inode = inode; | |
d20f7043 CM |
594 | cb->mirror_num = mirror_num; |
595 | sums = &cb->sums; | |
c8b97818 | 596 | |
ff5b7ee3 | 597 | cb->start = em->orig_start; |
e04ca626 CM |
598 | em_len = em->len; |
599 | em_start = em->start; | |
d20f7043 | 600 | |
c8b97818 | 601 | free_extent_map(em); |
e04ca626 | 602 | em = NULL; |
c8b97818 CM |
603 | |
604 | cb->len = uncompressed_len; | |
605 | cb->compressed_len = compressed_len; | |
606 | cb->orig_bio = bio; | |
607 | ||
608 | nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) / | |
609 | PAGE_CACHE_SIZE; | |
610 | cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages, | |
611 | GFP_NOFS); | |
612 | bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev; | |
613 | ||
614 | for (page_index = 0; page_index < nr_pages; page_index++) { | |
615 | cb->compressed_pages[page_index] = alloc_page(GFP_NOFS | | |
616 | __GFP_HIGHMEM); | |
617 | } | |
618 | cb->nr_pages = nr_pages; | |
619 | ||
e04ca626 | 620 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 621 | |
771ed689 CM |
622 | /* include any pages we added in add_ra-bio_pages */ |
623 | uncompressed_len = bio->bi_vcnt * PAGE_CACHE_SIZE; | |
624 | cb->len = uncompressed_len; | |
625 | ||
c8b97818 CM |
626 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
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; | |
694 | } |