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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> |
c8b97818 CM |
35 | #include "ctree.h" |
36 | #include "disk-io.h" | |
37 | #include "transaction.h" | |
38 | #include "btrfs_inode.h" | |
39 | #include "volumes.h" | |
40 | #include "ordered-data.h" | |
c8b97818 CM |
41 | #include "compression.h" |
42 | #include "extent_io.h" | |
43 | #include "extent_map.h" | |
44 | ||
45 | struct compressed_bio { | |
46 | /* number of bios pending for this compressed extent */ | |
47 | atomic_t pending_bios; | |
48 | ||
49 | /* the pages with the compressed data on them */ | |
50 | struct page **compressed_pages; | |
51 | ||
52 | /* inode that owns this data */ | |
53 | struct inode *inode; | |
54 | ||
55 | /* starting offset in the inode for our pages */ | |
56 | u64 start; | |
57 | ||
58 | /* number of bytes in the inode we're working on */ | |
59 | unsigned long len; | |
60 | ||
61 | /* number of bytes on disk */ | |
62 | unsigned long compressed_len; | |
63 | ||
261507a0 LZ |
64 | /* the compression algorithm for this bio */ |
65 | int compress_type; | |
66 | ||
c8b97818 CM |
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 | ||
974b1adc CH |
84 | static int btrfs_decompress_bio(int type, struct page **pages_in, |
85 | u64 disk_start, struct bio *orig_bio, | |
86 | size_t srclen); | |
48a3b636 | 87 | |
2ff7e61e | 88 | static inline int compressed_bio_size(struct btrfs_fs_info *fs_info, |
d20f7043 CM |
89 | unsigned long disk_size) |
90 | { | |
0b246afa | 91 | u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
6c41761f | 92 | |
d20f7043 | 93 | return sizeof(struct compressed_bio) + |
0b246afa | 94 | (DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * csum_size; |
d20f7043 CM |
95 | } |
96 | ||
c8b97818 CM |
97 | static struct bio *compressed_bio_alloc(struct block_device *bdev, |
98 | u64 first_byte, gfp_t gfp_flags) | |
99 | { | |
b54ffb73 | 100 | return btrfs_bio_alloc(bdev, first_byte >> 9, BIO_MAX_PAGES, 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; | |
d20f7043 CM |
108 | struct page *page; |
109 | unsigned long i; | |
110 | char *kaddr; | |
111 | u32 csum; | |
112 | u32 *cb_sum = &cb->sums; | |
113 | ||
6cbff00f | 114 | if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
115 | return 0; |
116 | ||
117 | for (i = 0; i < cb->nr_pages; i++) { | |
118 | page = cb->compressed_pages[i]; | |
119 | csum = ~(u32)0; | |
120 | ||
7ac687d9 | 121 | kaddr = kmap_atomic(page); |
09cbfeaf | 122 | csum = btrfs_csum_data(kaddr, csum, PAGE_SIZE); |
0b5e3daf | 123 | btrfs_csum_final(csum, (u8 *)&csum); |
7ac687d9 | 124 | kunmap_atomic(kaddr); |
d20f7043 CM |
125 | |
126 | if (csum != *cb_sum) { | |
efe120a0 FH |
127 | btrfs_info(BTRFS_I(inode)->root->fs_info, |
128 | "csum failed ino %llu extent %llu csum %u wanted %u mirror %d", | |
129 | btrfs_ino(inode), disk_start, csum, *cb_sum, | |
130 | cb->mirror_num); | |
d20f7043 CM |
131 | ret = -EIO; |
132 | goto fail; | |
133 | } | |
134 | cb_sum++; | |
135 | ||
136 | } | |
137 | ret = 0; | |
138 | fail: | |
139 | return ret; | |
140 | } | |
141 | ||
c8b97818 CM |
142 | /* when we finish reading compressed pages from the disk, we |
143 | * decompress them and then run the bio end_io routines on the | |
144 | * decompressed pages (in the inode address space). | |
145 | * | |
146 | * This allows the checksumming and other IO error handling routines | |
147 | * to work normally | |
148 | * | |
149 | * The compressed pages are freed here, and it must be run | |
150 | * in process context | |
151 | */ | |
4246a0b6 | 152 | static void end_compressed_bio_read(struct bio *bio) |
c8b97818 | 153 | { |
c8b97818 CM |
154 | struct compressed_bio *cb = bio->bi_private; |
155 | struct inode *inode; | |
156 | struct page *page; | |
157 | unsigned long index; | |
158 | int ret; | |
159 | ||
4246a0b6 | 160 | if (bio->bi_error) |
c8b97818 CM |
161 | cb->errors = 1; |
162 | ||
163 | /* if there are more bios still pending for this compressed | |
164 | * extent, just exit | |
165 | */ | |
166 | if (!atomic_dec_and_test(&cb->pending_bios)) | |
167 | goto out; | |
168 | ||
d20f7043 | 169 | inode = cb->inode; |
4f024f37 KO |
170 | ret = check_compressed_csum(inode, cb, |
171 | (u64)bio->bi_iter.bi_sector << 9); | |
d20f7043 CM |
172 | if (ret) |
173 | goto csum_failed; | |
174 | ||
c8b97818 CM |
175 | /* ok, we're the last bio for this extent, lets start |
176 | * the decompression. | |
177 | */ | |
974b1adc | 178 | ret = btrfs_decompress_bio(cb->compress_type, |
261507a0 LZ |
179 | cb->compressed_pages, |
180 | cb->start, | |
974b1adc | 181 | cb->orig_bio, |
261507a0 | 182 | cb->compressed_len); |
d20f7043 | 183 | csum_failed: |
c8b97818 CM |
184 | if (ret) |
185 | cb->errors = 1; | |
186 | ||
187 | /* release the compressed pages */ | |
188 | index = 0; | |
189 | for (index = 0; index < cb->nr_pages; index++) { | |
190 | page = cb->compressed_pages[index]; | |
191 | page->mapping = NULL; | |
09cbfeaf | 192 | put_page(page); |
c8b97818 CM |
193 | } |
194 | ||
195 | /* do io completion on the original bio */ | |
771ed689 | 196 | if (cb->errors) { |
c8b97818 | 197 | bio_io_error(cb->orig_bio); |
d20f7043 | 198 | } else { |
2c30c71b KO |
199 | int i; |
200 | struct bio_vec *bvec; | |
d20f7043 CM |
201 | |
202 | /* | |
203 | * we have verified the checksum already, set page | |
204 | * checked so the end_io handlers know about it | |
205 | */ | |
2c30c71b | 206 | bio_for_each_segment_all(bvec, cb->orig_bio, i) |
d20f7043 | 207 | SetPageChecked(bvec->bv_page); |
2c30c71b | 208 | |
4246a0b6 | 209 | bio_endio(cb->orig_bio); |
d20f7043 | 210 | } |
c8b97818 CM |
211 | |
212 | /* finally free the cb struct */ | |
213 | kfree(cb->compressed_pages); | |
214 | kfree(cb); | |
215 | out: | |
216 | bio_put(bio); | |
217 | } | |
218 | ||
219 | /* | |
220 | * Clear the writeback bits on all of the file | |
221 | * pages for a compressed write | |
222 | */ | |
7bdcefc1 FM |
223 | static noinline void end_compressed_writeback(struct inode *inode, |
224 | const struct compressed_bio *cb) | |
c8b97818 | 225 | { |
09cbfeaf KS |
226 | unsigned long index = cb->start >> PAGE_SHIFT; |
227 | unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT; | |
c8b97818 CM |
228 | struct page *pages[16]; |
229 | unsigned long nr_pages = end_index - index + 1; | |
230 | int i; | |
231 | int ret; | |
232 | ||
7bdcefc1 FM |
233 | if (cb->errors) |
234 | mapping_set_error(inode->i_mapping, -EIO); | |
235 | ||
d397712b | 236 | while (nr_pages > 0) { |
c8b97818 | 237 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
238 | min_t(unsigned long, |
239 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
240 | if (ret == 0) { |
241 | nr_pages -= 1; | |
242 | index += 1; | |
243 | continue; | |
244 | } | |
245 | for (i = 0; i < ret; i++) { | |
7bdcefc1 FM |
246 | if (cb->errors) |
247 | SetPageError(pages[i]); | |
c8b97818 | 248 | end_page_writeback(pages[i]); |
09cbfeaf | 249 | put_page(pages[i]); |
c8b97818 CM |
250 | } |
251 | nr_pages -= ret; | |
252 | index += ret; | |
253 | } | |
254 | /* the inode may be gone now */ | |
c8b97818 CM |
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 | */ | |
4246a0b6 | 265 | static void end_compressed_bio_write(struct bio *bio) |
c8b97818 CM |
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 | ||
4246a0b6 | 273 | if (bio->bi_error) |
c8b97818 CM |
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, | |
7bdcefc1 | 291 | NULL, |
4246a0b6 | 292 | bio->bi_error ? 0 : 1); |
70b99e69 | 293 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 | 294 | |
7bdcefc1 | 295 | end_compressed_writeback(inode, cb); |
c8b97818 CM |
296 | /* note, our inode could be gone now */ |
297 | ||
298 | /* | |
299 | * release the compressed pages, these came from alloc_page and | |
300 | * are not attached to the inode at all | |
301 | */ | |
302 | index = 0; | |
303 | for (index = 0; index < cb->nr_pages; index++) { | |
304 | page = cb->compressed_pages[index]; | |
305 | page->mapping = NULL; | |
09cbfeaf | 306 | put_page(page); |
c8b97818 CM |
307 | } |
308 | ||
309 | /* finally free the cb struct */ | |
310 | kfree(cb->compressed_pages); | |
311 | kfree(cb); | |
312 | out: | |
313 | bio_put(bio); | |
314 | } | |
315 | ||
316 | /* | |
317 | * worker function to build and submit bios for previously compressed pages. | |
318 | * The corresponding pages in the inode should be marked for writeback | |
319 | * and the compressed pages should have a reference on them for dropping | |
320 | * when the IO is complete. | |
321 | * | |
322 | * This also checksums the file bytes and gets things ready for | |
323 | * the end io hooks. | |
324 | */ | |
325 | int btrfs_submit_compressed_write(struct inode *inode, u64 start, | |
326 | unsigned long len, u64 disk_start, | |
327 | unsigned long compressed_len, | |
328 | struct page **compressed_pages, | |
329 | unsigned long nr_pages) | |
330 | { | |
0b246afa | 331 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 | 332 | struct bio *bio = NULL; |
c8b97818 CM |
333 | struct compressed_bio *cb; |
334 | unsigned long bytes_left; | |
335 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
306e16ce | 336 | int pg_index = 0; |
c8b97818 CM |
337 | struct page *page; |
338 | u64 first_byte = disk_start; | |
339 | struct block_device *bdev; | |
340 | int ret; | |
e55179b3 | 341 | int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; |
c8b97818 | 342 | |
09cbfeaf | 343 | WARN_ON(start & ((u64)PAGE_SIZE - 1)); |
2ff7e61e | 344 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
dac97e51 YS |
345 | if (!cb) |
346 | return -ENOMEM; | |
c8b97818 CM |
347 | atomic_set(&cb->pending_bios, 0); |
348 | cb->errors = 0; | |
349 | cb->inode = inode; | |
350 | cb->start = start; | |
351 | cb->len = len; | |
d20f7043 | 352 | cb->mirror_num = 0; |
c8b97818 CM |
353 | cb->compressed_pages = compressed_pages; |
354 | cb->compressed_len = compressed_len; | |
355 | cb->orig_bio = NULL; | |
356 | cb->nr_pages = nr_pages; | |
357 | ||
0b246afa | 358 | bdev = fs_info->fs_devices->latest_bdev; |
c8b97818 | 359 | |
c8b97818 | 360 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); |
67871254 | 361 | if (!bio) { |
dac97e51 YS |
362 | kfree(cb); |
363 | return -ENOMEM; | |
364 | } | |
37226b21 | 365 | bio_set_op_attrs(bio, REQ_OP_WRITE, 0); |
c8b97818 CM |
366 | bio->bi_private = cb; |
367 | bio->bi_end_io = end_compressed_bio_write; | |
368 | atomic_inc(&cb->pending_bios); | |
369 | ||
370 | /* create and submit bios for the compressed pages */ | |
371 | bytes_left = compressed_len; | |
306e16ce DS |
372 | for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { |
373 | page = compressed_pages[pg_index]; | |
c8b97818 | 374 | page->mapping = inode->i_mapping; |
4f024f37 | 375 | if (bio->bi_iter.bi_size) |
81a75f67 | 376 | ret = io_tree->ops->merge_bio_hook(page, 0, |
09cbfeaf | 377 | PAGE_SIZE, |
c8b97818 CM |
378 | bio, 0); |
379 | else | |
380 | ret = 0; | |
381 | ||
70b99e69 | 382 | page->mapping = NULL; |
09cbfeaf KS |
383 | if (ret || bio_add_page(bio, page, PAGE_SIZE, 0) < |
384 | PAGE_SIZE) { | |
c8b97818 CM |
385 | bio_get(bio); |
386 | ||
af09abfe CM |
387 | /* |
388 | * inc the count before we submit the bio so | |
389 | * we know the end IO handler won't happen before | |
390 | * we inc the count. Otherwise, the cb might get | |
391 | * freed before we're done setting it up | |
392 | */ | |
393 | atomic_inc(&cb->pending_bios); | |
0b246afa JM |
394 | ret = btrfs_bio_wq_end_io(fs_info, bio, |
395 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 396 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 397 | |
e55179b3 | 398 | if (!skip_sum) { |
2ff7e61e | 399 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 400 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 401 | } |
d20f7043 | 402 | |
2ff7e61e | 403 | ret = btrfs_map_bio(fs_info, bio, 0, 1); |
f5daf2c7 LB |
404 | if (ret) { |
405 | bio->bi_error = ret; | |
406 | bio_endio(bio); | |
407 | } | |
c8b97818 CM |
408 | |
409 | bio_put(bio); | |
410 | ||
411 | bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS); | |
e627ee7b | 412 | BUG_ON(!bio); |
37226b21 | 413 | bio_set_op_attrs(bio, REQ_OP_WRITE, 0); |
c8b97818 CM |
414 | bio->bi_private = cb; |
415 | bio->bi_end_io = end_compressed_bio_write; | |
09cbfeaf | 416 | bio_add_page(bio, page, PAGE_SIZE, 0); |
c8b97818 | 417 | } |
09cbfeaf | 418 | if (bytes_left < PAGE_SIZE) { |
0b246afa | 419 | btrfs_info(fs_info, |
efe120a0 | 420 | "bytes left %lu compress len %lu nr %lu", |
cfbc246e CM |
421 | bytes_left, cb->compressed_len, cb->nr_pages); |
422 | } | |
09cbfeaf KS |
423 | bytes_left -= PAGE_SIZE; |
424 | first_byte += PAGE_SIZE; | |
771ed689 | 425 | cond_resched(); |
c8b97818 CM |
426 | } |
427 | bio_get(bio); | |
428 | ||
0b246afa | 429 | ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 430 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 431 | |
e55179b3 | 432 | if (!skip_sum) { |
2ff7e61e | 433 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 434 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 435 | } |
d20f7043 | 436 | |
2ff7e61e | 437 | ret = btrfs_map_bio(fs_info, bio, 0, 1); |
f5daf2c7 LB |
438 | if (ret) { |
439 | bio->bi_error = ret; | |
440 | bio_endio(bio); | |
441 | } | |
c8b97818 CM |
442 | |
443 | bio_put(bio); | |
444 | return 0; | |
445 | } | |
446 | ||
2a4d0c90 CH |
447 | static u64 bio_end_offset(struct bio *bio) |
448 | { | |
449 | struct bio_vec *last = &bio->bi_io_vec[bio->bi_vcnt - 1]; | |
450 | ||
451 | return page_offset(last->bv_page) + last->bv_len + last->bv_offset; | |
452 | } | |
453 | ||
771ed689 CM |
454 | static noinline int add_ra_bio_pages(struct inode *inode, |
455 | u64 compressed_end, | |
456 | struct compressed_bio *cb) | |
457 | { | |
458 | unsigned long end_index; | |
306e16ce | 459 | unsigned long pg_index; |
771ed689 CM |
460 | u64 last_offset; |
461 | u64 isize = i_size_read(inode); | |
462 | int ret; | |
463 | struct page *page; | |
464 | unsigned long nr_pages = 0; | |
465 | struct extent_map *em; | |
466 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
467 | struct extent_map_tree *em_tree; |
468 | struct extent_io_tree *tree; | |
469 | u64 end; | |
470 | int misses = 0; | |
471 | ||
2a4d0c90 | 472 | last_offset = bio_end_offset(cb->orig_bio); |
771ed689 CM |
473 | em_tree = &BTRFS_I(inode)->extent_tree; |
474 | tree = &BTRFS_I(inode)->io_tree; | |
475 | ||
476 | if (isize == 0) | |
477 | return 0; | |
478 | ||
09cbfeaf | 479 | end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; |
771ed689 | 480 | |
d397712b | 481 | while (last_offset < compressed_end) { |
09cbfeaf | 482 | pg_index = last_offset >> PAGE_SHIFT; |
771ed689 | 483 | |
306e16ce | 484 | if (pg_index > end_index) |
771ed689 CM |
485 | break; |
486 | ||
487 | rcu_read_lock(); | |
306e16ce | 488 | page = radix_tree_lookup(&mapping->page_tree, pg_index); |
771ed689 | 489 | rcu_read_unlock(); |
0cd6144a | 490 | if (page && !radix_tree_exceptional_entry(page)) { |
771ed689 CM |
491 | misses++; |
492 | if (misses > 4) | |
493 | break; | |
494 | goto next; | |
495 | } | |
496 | ||
c62d2555 MH |
497 | page = __page_cache_alloc(mapping_gfp_constraint(mapping, |
498 | ~__GFP_FS)); | |
771ed689 CM |
499 | if (!page) |
500 | break; | |
501 | ||
c62d2555 | 502 | if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) { |
09cbfeaf | 503 | put_page(page); |
771ed689 CM |
504 | goto next; |
505 | } | |
506 | ||
09cbfeaf | 507 | end = last_offset + PAGE_SIZE - 1; |
771ed689 CM |
508 | /* |
509 | * at this point, we have a locked page in the page cache | |
510 | * for these bytes in the file. But, we have to make | |
511 | * sure they map to this compressed extent on disk. | |
512 | */ | |
513 | set_page_extent_mapped(page); | |
d0082371 | 514 | lock_extent(tree, last_offset, end); |
890871be | 515 | read_lock(&em_tree->lock); |
771ed689 | 516 | em = lookup_extent_mapping(em_tree, last_offset, |
09cbfeaf | 517 | PAGE_SIZE); |
890871be | 518 | read_unlock(&em_tree->lock); |
771ed689 CM |
519 | |
520 | if (!em || last_offset < em->start || | |
09cbfeaf | 521 | (last_offset + PAGE_SIZE > extent_map_end(em)) || |
4f024f37 | 522 | (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) { |
771ed689 | 523 | free_extent_map(em); |
d0082371 | 524 | unlock_extent(tree, last_offset, end); |
771ed689 | 525 | unlock_page(page); |
09cbfeaf | 526 | put_page(page); |
771ed689 CM |
527 | break; |
528 | } | |
529 | free_extent_map(em); | |
530 | ||
531 | if (page->index == end_index) { | |
532 | char *userpage; | |
09cbfeaf | 533 | size_t zero_offset = isize & (PAGE_SIZE - 1); |
771ed689 CM |
534 | |
535 | if (zero_offset) { | |
536 | int zeros; | |
09cbfeaf | 537 | zeros = PAGE_SIZE - zero_offset; |
7ac687d9 | 538 | userpage = kmap_atomic(page); |
771ed689 CM |
539 | memset(userpage + zero_offset, 0, zeros); |
540 | flush_dcache_page(page); | |
7ac687d9 | 541 | kunmap_atomic(userpage); |
771ed689 CM |
542 | } |
543 | } | |
544 | ||
545 | ret = bio_add_page(cb->orig_bio, page, | |
09cbfeaf | 546 | PAGE_SIZE, 0); |
771ed689 | 547 | |
09cbfeaf | 548 | if (ret == PAGE_SIZE) { |
771ed689 | 549 | nr_pages++; |
09cbfeaf | 550 | put_page(page); |
771ed689 | 551 | } else { |
d0082371 | 552 | unlock_extent(tree, last_offset, end); |
771ed689 | 553 | unlock_page(page); |
09cbfeaf | 554 | put_page(page); |
771ed689 CM |
555 | break; |
556 | } | |
557 | next: | |
09cbfeaf | 558 | last_offset += PAGE_SIZE; |
771ed689 | 559 | } |
771ed689 CM |
560 | return 0; |
561 | } | |
562 | ||
c8b97818 CM |
563 | /* |
564 | * for a compressed read, the bio we get passed has all the inode pages | |
565 | * in it. We don't actually do IO on those pages but allocate new ones | |
566 | * to hold the compressed pages on disk. | |
567 | * | |
4f024f37 | 568 | * bio->bi_iter.bi_sector points to the compressed extent on disk |
c8b97818 | 569 | * bio->bi_io_vec points to all of the inode pages |
c8b97818 CM |
570 | * |
571 | * After the compressed pages are read, we copy the bytes into the | |
572 | * bio we were passed and then call the bio end_io calls | |
573 | */ | |
574 | int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, | |
575 | int mirror_num, unsigned long bio_flags) | |
576 | { | |
0b246afa | 577 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 CM |
578 | struct extent_io_tree *tree; |
579 | struct extent_map_tree *em_tree; | |
580 | struct compressed_bio *cb; | |
c8b97818 CM |
581 | unsigned long compressed_len; |
582 | unsigned long nr_pages; | |
306e16ce | 583 | unsigned long pg_index; |
c8b97818 CM |
584 | struct page *page; |
585 | struct block_device *bdev; | |
586 | struct bio *comp_bio; | |
4f024f37 | 587 | u64 cur_disk_byte = (u64)bio->bi_iter.bi_sector << 9; |
e04ca626 CM |
588 | u64 em_len; |
589 | u64 em_start; | |
c8b97818 | 590 | struct extent_map *em; |
6b82ce8d | 591 | int ret = -ENOMEM; |
15e3004a | 592 | int faili = 0; |
d20f7043 | 593 | u32 *sums; |
c8b97818 CM |
594 | |
595 | tree = &BTRFS_I(inode)->io_tree; | |
596 | em_tree = &BTRFS_I(inode)->extent_tree; | |
597 | ||
598 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 599 | read_lock(&em_tree->lock); |
c8b97818 CM |
600 | em = lookup_extent_mapping(em_tree, |
601 | page_offset(bio->bi_io_vec->bv_page), | |
09cbfeaf | 602 | PAGE_SIZE); |
890871be | 603 | read_unlock(&em_tree->lock); |
285190d9 TI |
604 | if (!em) |
605 | return -EIO; | |
c8b97818 | 606 | |
d20f7043 | 607 | compressed_len = em->block_len; |
2ff7e61e | 608 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
6b82ce8d | 609 | if (!cb) |
610 | goto out; | |
611 | ||
c8b97818 CM |
612 | atomic_set(&cb->pending_bios, 0); |
613 | cb->errors = 0; | |
614 | cb->inode = inode; | |
d20f7043 CM |
615 | cb->mirror_num = mirror_num; |
616 | sums = &cb->sums; | |
c8b97818 | 617 | |
ff5b7ee3 | 618 | cb->start = em->orig_start; |
e04ca626 CM |
619 | em_len = em->len; |
620 | em_start = em->start; | |
d20f7043 | 621 | |
c8b97818 | 622 | free_extent_map(em); |
e04ca626 | 623 | em = NULL; |
c8b97818 | 624 | |
81381053 | 625 | cb->len = bio->bi_iter.bi_size; |
c8b97818 | 626 | cb->compressed_len = compressed_len; |
261507a0 | 627 | cb->compress_type = extent_compress_type(bio_flags); |
c8b97818 CM |
628 | cb->orig_bio = bio; |
629 | ||
09cbfeaf | 630 | nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); |
31e818fe | 631 | cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *), |
c8b97818 | 632 | GFP_NOFS); |
6b82ce8d | 633 | if (!cb->compressed_pages) |
634 | goto fail1; | |
635 | ||
0b246afa | 636 | bdev = fs_info->fs_devices->latest_bdev; |
c8b97818 | 637 | |
306e16ce DS |
638 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
639 | cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | | |
c8b97818 | 640 | __GFP_HIGHMEM); |
15e3004a JB |
641 | if (!cb->compressed_pages[pg_index]) { |
642 | faili = pg_index - 1; | |
643 | ret = -ENOMEM; | |
6b82ce8d | 644 | goto fail2; |
15e3004a | 645 | } |
c8b97818 | 646 | } |
15e3004a | 647 | faili = nr_pages - 1; |
c8b97818 CM |
648 | cb->nr_pages = nr_pages; |
649 | ||
7f042a83 | 650 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 651 | |
771ed689 | 652 | /* include any pages we added in add_ra-bio_pages */ |
81381053 | 653 | cb->len = bio->bi_iter.bi_size; |
771ed689 | 654 | |
c8b97818 | 655 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS); |
6b82ce8d | 656 | if (!comp_bio) |
657 | goto fail2; | |
37226b21 | 658 | bio_set_op_attrs (comp_bio, REQ_OP_READ, 0); |
c8b97818 CM |
659 | comp_bio->bi_private = cb; |
660 | comp_bio->bi_end_io = end_compressed_bio_read; | |
661 | atomic_inc(&cb->pending_bios); | |
662 | ||
306e16ce DS |
663 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
664 | page = cb->compressed_pages[pg_index]; | |
c8b97818 | 665 | page->mapping = inode->i_mapping; |
09cbfeaf | 666 | page->index = em_start >> PAGE_SHIFT; |
d20f7043 | 667 | |
4f024f37 | 668 | if (comp_bio->bi_iter.bi_size) |
81a75f67 | 669 | ret = tree->ops->merge_bio_hook(page, 0, |
09cbfeaf | 670 | PAGE_SIZE, |
c8b97818 CM |
671 | comp_bio, 0); |
672 | else | |
673 | ret = 0; | |
674 | ||
70b99e69 | 675 | page->mapping = NULL; |
09cbfeaf KS |
676 | if (ret || bio_add_page(comp_bio, page, PAGE_SIZE, 0) < |
677 | PAGE_SIZE) { | |
c8b97818 CM |
678 | bio_get(comp_bio); |
679 | ||
0b246afa JM |
680 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, |
681 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 682 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 683 | |
af09abfe CM |
684 | /* |
685 | * inc the count before we submit the bio so | |
686 | * we know the end IO handler won't happen before | |
687 | * we inc the count. Otherwise, the cb might get | |
688 | * freed before we're done setting it up | |
689 | */ | |
690 | atomic_inc(&cb->pending_bios); | |
691 | ||
6cbff00f | 692 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
2ff7e61e JM |
693 | ret = btrfs_lookup_bio_sums(inode, comp_bio, |
694 | sums); | |
79787eaa | 695 | BUG_ON(ret); /* -ENOMEM */ |
d20f7043 | 696 | } |
ed6078f7 | 697 | sums += DIV_ROUND_UP(comp_bio->bi_iter.bi_size, |
0b246afa | 698 | fs_info->sectorsize); |
d20f7043 | 699 | |
2ff7e61e | 700 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num, 0); |
4246a0b6 | 701 | if (ret) { |
14155caf | 702 | comp_bio->bi_error = ret; |
4246a0b6 CH |
703 | bio_endio(comp_bio); |
704 | } | |
c8b97818 CM |
705 | |
706 | bio_put(comp_bio); | |
707 | ||
708 | comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, | |
709 | GFP_NOFS); | |
e627ee7b | 710 | BUG_ON(!comp_bio); |
37226b21 | 711 | bio_set_op_attrs(comp_bio, REQ_OP_READ, 0); |
771ed689 CM |
712 | comp_bio->bi_private = cb; |
713 | comp_bio->bi_end_io = end_compressed_bio_read; | |
714 | ||
09cbfeaf | 715 | bio_add_page(comp_bio, page, PAGE_SIZE, 0); |
c8b97818 | 716 | } |
09cbfeaf | 717 | cur_disk_byte += PAGE_SIZE; |
c8b97818 CM |
718 | } |
719 | bio_get(comp_bio); | |
720 | ||
0b246afa | 721 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 722 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 723 | |
c2db1073 | 724 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
2ff7e61e | 725 | ret = btrfs_lookup_bio_sums(inode, comp_bio, sums); |
79787eaa | 726 | BUG_ON(ret); /* -ENOMEM */ |
c2db1073 | 727 | } |
d20f7043 | 728 | |
2ff7e61e | 729 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num, 0); |
4246a0b6 | 730 | if (ret) { |
14155caf | 731 | comp_bio->bi_error = ret; |
4246a0b6 CH |
732 | bio_endio(comp_bio); |
733 | } | |
c8b97818 CM |
734 | |
735 | bio_put(comp_bio); | |
736 | return 0; | |
6b82ce8d | 737 | |
738 | fail2: | |
15e3004a JB |
739 | while (faili >= 0) { |
740 | __free_page(cb->compressed_pages[faili]); | |
741 | faili--; | |
742 | } | |
6b82ce8d | 743 | |
744 | kfree(cb->compressed_pages); | |
745 | fail1: | |
746 | kfree(cb); | |
747 | out: | |
748 | free_extent_map(em); | |
749 | return ret; | |
c8b97818 | 750 | } |
261507a0 | 751 | |
d9187649 BL |
752 | static struct { |
753 | struct list_head idle_ws; | |
754 | spinlock_t ws_lock; | |
6ac10a6a DS |
755 | /* Number of free workspaces */ |
756 | int free_ws; | |
757 | /* Total number of allocated workspaces */ | |
758 | atomic_t total_ws; | |
759 | /* Waiters for a free workspace */ | |
d9187649 BL |
760 | wait_queue_head_t ws_wait; |
761 | } btrfs_comp_ws[BTRFS_COMPRESS_TYPES]; | |
261507a0 | 762 | |
e8c9f186 | 763 | static const struct btrfs_compress_op * const btrfs_compress_op[] = { |
261507a0 | 764 | &btrfs_zlib_compress, |
a6fa6fae | 765 | &btrfs_lzo_compress, |
261507a0 LZ |
766 | }; |
767 | ||
143bede5 | 768 | void __init btrfs_init_compress(void) |
261507a0 LZ |
769 | { |
770 | int i; | |
771 | ||
772 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
f77dd0d6 DS |
773 | struct list_head *workspace; |
774 | ||
d9187649 BL |
775 | INIT_LIST_HEAD(&btrfs_comp_ws[i].idle_ws); |
776 | spin_lock_init(&btrfs_comp_ws[i].ws_lock); | |
6ac10a6a | 777 | atomic_set(&btrfs_comp_ws[i].total_ws, 0); |
d9187649 | 778 | init_waitqueue_head(&btrfs_comp_ws[i].ws_wait); |
f77dd0d6 DS |
779 | |
780 | /* | |
781 | * Preallocate one workspace for each compression type so | |
782 | * we can guarantee forward progress in the worst case | |
783 | */ | |
784 | workspace = btrfs_compress_op[i]->alloc_workspace(); | |
785 | if (IS_ERR(workspace)) { | |
62e85577 | 786 | pr_warn("BTRFS: cannot preallocate compression workspace, will try later\n"); |
f77dd0d6 DS |
787 | } else { |
788 | atomic_set(&btrfs_comp_ws[i].total_ws, 1); | |
789 | btrfs_comp_ws[i].free_ws = 1; | |
790 | list_add(workspace, &btrfs_comp_ws[i].idle_ws); | |
791 | } | |
261507a0 | 792 | } |
261507a0 LZ |
793 | } |
794 | ||
795 | /* | |
e721e49d DS |
796 | * This finds an available workspace or allocates a new one. |
797 | * If it's not possible to allocate a new one, waits until there's one. | |
798 | * Preallocation makes a forward progress guarantees and we do not return | |
799 | * errors. | |
261507a0 LZ |
800 | */ |
801 | static struct list_head *find_workspace(int type) | |
802 | { | |
803 | struct list_head *workspace; | |
804 | int cpus = num_online_cpus(); | |
805 | int idx = type - 1; | |
806 | ||
d9187649 BL |
807 | struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; |
808 | spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; | |
6ac10a6a | 809 | atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; |
d9187649 | 810 | wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; |
6ac10a6a | 811 | int *free_ws = &btrfs_comp_ws[idx].free_ws; |
261507a0 | 812 | again: |
d9187649 BL |
813 | spin_lock(ws_lock); |
814 | if (!list_empty(idle_ws)) { | |
815 | workspace = idle_ws->next; | |
261507a0 | 816 | list_del(workspace); |
6ac10a6a | 817 | (*free_ws)--; |
d9187649 | 818 | spin_unlock(ws_lock); |
261507a0 LZ |
819 | return workspace; |
820 | ||
821 | } | |
6ac10a6a | 822 | if (atomic_read(total_ws) > cpus) { |
261507a0 LZ |
823 | DEFINE_WAIT(wait); |
824 | ||
d9187649 BL |
825 | spin_unlock(ws_lock); |
826 | prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE); | |
6ac10a6a | 827 | if (atomic_read(total_ws) > cpus && !*free_ws) |
261507a0 | 828 | schedule(); |
d9187649 | 829 | finish_wait(ws_wait, &wait); |
261507a0 LZ |
830 | goto again; |
831 | } | |
6ac10a6a | 832 | atomic_inc(total_ws); |
d9187649 | 833 | spin_unlock(ws_lock); |
261507a0 LZ |
834 | |
835 | workspace = btrfs_compress_op[idx]->alloc_workspace(); | |
836 | if (IS_ERR(workspace)) { | |
6ac10a6a | 837 | atomic_dec(total_ws); |
d9187649 | 838 | wake_up(ws_wait); |
e721e49d DS |
839 | |
840 | /* | |
841 | * Do not return the error but go back to waiting. There's a | |
842 | * workspace preallocated for each type and the compression | |
843 | * time is bounded so we get to a workspace eventually. This | |
844 | * makes our caller's life easier. | |
52356716 DS |
845 | * |
846 | * To prevent silent and low-probability deadlocks (when the | |
847 | * initial preallocation fails), check if there are any | |
848 | * workspaces at all. | |
e721e49d | 849 | */ |
52356716 DS |
850 | if (atomic_read(total_ws) == 0) { |
851 | static DEFINE_RATELIMIT_STATE(_rs, | |
852 | /* once per minute */ 60 * HZ, | |
853 | /* no burst */ 1); | |
854 | ||
855 | if (__ratelimit(&_rs)) { | |
ab8d0fc4 | 856 | pr_warn("BTRFS: no compression workspaces, low memory, retrying\n"); |
52356716 DS |
857 | } |
858 | } | |
e721e49d | 859 | goto again; |
261507a0 LZ |
860 | } |
861 | return workspace; | |
862 | } | |
863 | ||
864 | /* | |
865 | * put a workspace struct back on the list or free it if we have enough | |
866 | * idle ones sitting around | |
867 | */ | |
868 | static void free_workspace(int type, struct list_head *workspace) | |
869 | { | |
870 | int idx = type - 1; | |
d9187649 BL |
871 | struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; |
872 | spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; | |
6ac10a6a | 873 | atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; |
d9187649 | 874 | wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; |
6ac10a6a | 875 | int *free_ws = &btrfs_comp_ws[idx].free_ws; |
d9187649 BL |
876 | |
877 | spin_lock(ws_lock); | |
6ac10a6a | 878 | if (*free_ws < num_online_cpus()) { |
d9187649 | 879 | list_add(workspace, idle_ws); |
6ac10a6a | 880 | (*free_ws)++; |
d9187649 | 881 | spin_unlock(ws_lock); |
261507a0 LZ |
882 | goto wake; |
883 | } | |
d9187649 | 884 | spin_unlock(ws_lock); |
261507a0 LZ |
885 | |
886 | btrfs_compress_op[idx]->free_workspace(workspace); | |
6ac10a6a | 887 | atomic_dec(total_ws); |
261507a0 | 888 | wake: |
a83342aa DS |
889 | /* |
890 | * Make sure counter is updated before we wake up waiters. | |
891 | */ | |
66657b31 | 892 | smp_mb(); |
d9187649 BL |
893 | if (waitqueue_active(ws_wait)) |
894 | wake_up(ws_wait); | |
261507a0 LZ |
895 | } |
896 | ||
897 | /* | |
898 | * cleanup function for module exit | |
899 | */ | |
900 | static void free_workspaces(void) | |
901 | { | |
902 | struct list_head *workspace; | |
903 | int i; | |
904 | ||
905 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
d9187649 BL |
906 | while (!list_empty(&btrfs_comp_ws[i].idle_ws)) { |
907 | workspace = btrfs_comp_ws[i].idle_ws.next; | |
261507a0 LZ |
908 | list_del(workspace); |
909 | btrfs_compress_op[i]->free_workspace(workspace); | |
6ac10a6a | 910 | atomic_dec(&btrfs_comp_ws[i].total_ws); |
261507a0 LZ |
911 | } |
912 | } | |
913 | } | |
914 | ||
915 | /* | |
916 | * given an address space and start/len, compress the bytes. | |
917 | * | |
918 | * pages are allocated to hold the compressed result and stored | |
919 | * in 'pages' | |
920 | * | |
921 | * out_pages is used to return the number of pages allocated. There | |
922 | * may be pages allocated even if we return an error | |
923 | * | |
924 | * total_in is used to return the number of bytes actually read. It | |
925 | * may be smaller then len if we had to exit early because we | |
926 | * ran out of room in the pages array or because we cross the | |
927 | * max_out threshold. | |
928 | * | |
929 | * total_out is used to return the total number of compressed bytes | |
930 | * | |
931 | * max_out tells us the max number of bytes that we're allowed to | |
932 | * stuff into pages | |
933 | */ | |
934 | int btrfs_compress_pages(int type, struct address_space *mapping, | |
935 | u64 start, unsigned long len, | |
936 | struct page **pages, | |
937 | unsigned long nr_dest_pages, | |
938 | unsigned long *out_pages, | |
939 | unsigned long *total_in, | |
940 | unsigned long *total_out, | |
941 | unsigned long max_out) | |
942 | { | |
943 | struct list_head *workspace; | |
944 | int ret; | |
945 | ||
946 | workspace = find_workspace(type); | |
261507a0 LZ |
947 | |
948 | ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, | |
949 | start, len, pages, | |
950 | nr_dest_pages, out_pages, | |
951 | total_in, total_out, | |
952 | max_out); | |
953 | free_workspace(type, workspace); | |
954 | return ret; | |
955 | } | |
956 | ||
957 | /* | |
958 | * pages_in is an array of pages with compressed data. | |
959 | * | |
960 | * disk_start is the starting logical offset of this array in the file | |
961 | * | |
974b1adc | 962 | * orig_bio contains the pages from the file that we want to decompress into |
261507a0 LZ |
963 | * |
964 | * srclen is the number of bytes in pages_in | |
965 | * | |
966 | * The basic idea is that we have a bio that was created by readpages. | |
967 | * The pages in the bio are for the uncompressed data, and they may not | |
968 | * be contiguous. They all correspond to the range of bytes covered by | |
969 | * the compressed extent. | |
970 | */ | |
974b1adc CH |
971 | static int btrfs_decompress_bio(int type, struct page **pages_in, |
972 | u64 disk_start, struct bio *orig_bio, | |
973 | size_t srclen) | |
261507a0 LZ |
974 | { |
975 | struct list_head *workspace; | |
976 | int ret; | |
977 | ||
978 | workspace = find_workspace(type); | |
261507a0 | 979 | |
974b1adc CH |
980 | ret = btrfs_compress_op[type-1]->decompress_bio(workspace, pages_in, |
981 | disk_start, orig_bio, | |
982 | srclen); | |
261507a0 LZ |
983 | free_workspace(type, workspace); |
984 | return ret; | |
985 | } | |
986 | ||
987 | /* | |
988 | * a less complex decompression routine. Our compressed data fits in a | |
989 | * single page, and we want to read a single page out of it. | |
990 | * start_byte tells us the offset into the compressed data we're interested in | |
991 | */ | |
992 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, | |
993 | unsigned long start_byte, size_t srclen, size_t destlen) | |
994 | { | |
995 | struct list_head *workspace; | |
996 | int ret; | |
997 | ||
998 | workspace = find_workspace(type); | |
261507a0 LZ |
999 | |
1000 | ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, | |
1001 | dest_page, start_byte, | |
1002 | srclen, destlen); | |
1003 | ||
1004 | free_workspace(type, workspace); | |
1005 | return ret; | |
1006 | } | |
1007 | ||
8e4eef7a | 1008 | void btrfs_exit_compress(void) |
261507a0 LZ |
1009 | { |
1010 | free_workspaces(); | |
1011 | } | |
3a39c18d LZ |
1012 | |
1013 | /* | |
1014 | * Copy uncompressed data from working buffer to pages. | |
1015 | * | |
1016 | * buf_start is the byte offset we're of the start of our workspace buffer. | |
1017 | * | |
1018 | * total_out is the last byte of the buffer | |
1019 | */ | |
1020 | int btrfs_decompress_buf2page(char *buf, unsigned long buf_start, | |
1021 | unsigned long total_out, u64 disk_start, | |
974b1adc | 1022 | struct bio *bio) |
3a39c18d LZ |
1023 | { |
1024 | unsigned long buf_offset; | |
1025 | unsigned long current_buf_start; | |
1026 | unsigned long start_byte; | |
6e78b3f7 | 1027 | unsigned long prev_start_byte; |
3a39c18d LZ |
1028 | unsigned long working_bytes = total_out - buf_start; |
1029 | unsigned long bytes; | |
1030 | char *kaddr; | |
974b1adc | 1031 | struct bio_vec bvec = bio_iter_iovec(bio, bio->bi_iter); |
3a39c18d LZ |
1032 | |
1033 | /* | |
1034 | * start byte is the first byte of the page we're currently | |
1035 | * copying into relative to the start of the compressed data. | |
1036 | */ | |
974b1adc | 1037 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d LZ |
1038 | |
1039 | /* we haven't yet hit data corresponding to this page */ | |
1040 | if (total_out <= start_byte) | |
1041 | return 1; | |
1042 | ||
1043 | /* | |
1044 | * the start of the data we care about is offset into | |
1045 | * the middle of our working buffer | |
1046 | */ | |
1047 | if (total_out > start_byte && buf_start < start_byte) { | |
1048 | buf_offset = start_byte - buf_start; | |
1049 | working_bytes -= buf_offset; | |
1050 | } else { | |
1051 | buf_offset = 0; | |
1052 | } | |
1053 | current_buf_start = buf_start; | |
1054 | ||
1055 | /* copy bytes from the working buffer into the pages */ | |
1056 | while (working_bytes > 0) { | |
974b1adc CH |
1057 | bytes = min_t(unsigned long, bvec.bv_len, |
1058 | PAGE_SIZE - buf_offset); | |
3a39c18d | 1059 | bytes = min(bytes, working_bytes); |
974b1adc CH |
1060 | |
1061 | kaddr = kmap_atomic(bvec.bv_page); | |
1062 | memcpy(kaddr + bvec.bv_offset, buf + buf_offset, bytes); | |
7ac687d9 | 1063 | kunmap_atomic(kaddr); |
974b1adc | 1064 | flush_dcache_page(bvec.bv_page); |
3a39c18d | 1065 | |
3a39c18d LZ |
1066 | buf_offset += bytes; |
1067 | working_bytes -= bytes; | |
1068 | current_buf_start += bytes; | |
1069 | ||
1070 | /* check if we need to pick another page */ | |
974b1adc CH |
1071 | bio_advance(bio, bytes); |
1072 | if (!bio->bi_iter.bi_size) | |
1073 | return 0; | |
1074 | bvec = bio_iter_iovec(bio, bio->bi_iter); | |
6e78b3f7 | 1075 | prev_start_byte = start_byte; |
974b1adc | 1076 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d | 1077 | |
974b1adc | 1078 | /* |
6e78b3f7 OS |
1079 | * We need to make sure we're only adjusting |
1080 | * our offset into compression working buffer when | |
1081 | * we're switching pages. Otherwise we can incorrectly | |
1082 | * keep copying when we were actually done. | |
974b1adc | 1083 | */ |
6e78b3f7 OS |
1084 | if (start_byte != prev_start_byte) { |
1085 | /* | |
1086 | * make sure our new page is covered by this | |
1087 | * working buffer | |
1088 | */ | |
1089 | if (total_out <= start_byte) | |
1090 | return 1; | |
3a39c18d | 1091 | |
6e78b3f7 OS |
1092 | /* |
1093 | * the next page in the biovec might not be adjacent | |
1094 | * to the last page, but it might still be found | |
1095 | * inside this working buffer. bump our offset pointer | |
1096 | */ | |
1097 | if (total_out > start_byte && | |
1098 | current_buf_start < start_byte) { | |
1099 | buf_offset = start_byte - buf_start; | |
1100 | working_bytes = total_out - start_byte; | |
1101 | current_buf_start = buf_start + buf_offset; | |
1102 | } | |
3a39c18d LZ |
1103 | } |
1104 | } | |
1105 | ||
1106 | return 1; | |
1107 | } |