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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> |
fe308533 | 35 | #include <linux/sched/mm.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 | ||
8140dc30 | 46 | static int btrfs_decompress_bio(struct compressed_bio *cb); |
48a3b636 | 47 | |
2ff7e61e | 48 | static inline int compressed_bio_size(struct btrfs_fs_info *fs_info, |
d20f7043 CM |
49 | unsigned long disk_size) |
50 | { | |
0b246afa | 51 | u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
6c41761f | 52 | |
d20f7043 | 53 | return sizeof(struct compressed_bio) + |
0b246afa | 54 | (DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * csum_size; |
d20f7043 CM |
55 | } |
56 | ||
f898ac6a | 57 | static int check_compressed_csum(struct btrfs_inode *inode, |
d20f7043 CM |
58 | struct compressed_bio *cb, |
59 | u64 disk_start) | |
60 | { | |
61 | int ret; | |
d20f7043 CM |
62 | struct page *page; |
63 | unsigned long i; | |
64 | char *kaddr; | |
65 | u32 csum; | |
66 | u32 *cb_sum = &cb->sums; | |
67 | ||
f898ac6a | 68 | if (inode->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
69 | return 0; |
70 | ||
71 | for (i = 0; i < cb->nr_pages; i++) { | |
72 | page = cb->compressed_pages[i]; | |
73 | csum = ~(u32)0; | |
74 | ||
7ac687d9 | 75 | kaddr = kmap_atomic(page); |
09cbfeaf | 76 | csum = btrfs_csum_data(kaddr, csum, PAGE_SIZE); |
0b5e3daf | 77 | btrfs_csum_final(csum, (u8 *)&csum); |
7ac687d9 | 78 | kunmap_atomic(kaddr); |
d20f7043 CM |
79 | |
80 | if (csum != *cb_sum) { | |
f898ac6a | 81 | btrfs_print_data_csum_error(inode, disk_start, csum, |
0970a22e | 82 | *cb_sum, cb->mirror_num); |
d20f7043 CM |
83 | ret = -EIO; |
84 | goto fail; | |
85 | } | |
86 | cb_sum++; | |
87 | ||
88 | } | |
89 | ret = 0; | |
90 | fail: | |
91 | return ret; | |
92 | } | |
93 | ||
c8b97818 CM |
94 | /* when we finish reading compressed pages from the disk, we |
95 | * decompress them and then run the bio end_io routines on the | |
96 | * decompressed pages (in the inode address space). | |
97 | * | |
98 | * This allows the checksumming and other IO error handling routines | |
99 | * to work normally | |
100 | * | |
101 | * The compressed pages are freed here, and it must be run | |
102 | * in process context | |
103 | */ | |
4246a0b6 | 104 | static void end_compressed_bio_read(struct bio *bio) |
c8b97818 | 105 | { |
c8b97818 CM |
106 | struct compressed_bio *cb = bio->bi_private; |
107 | struct inode *inode; | |
108 | struct page *page; | |
109 | unsigned long index; | |
cf1167d5 | 110 | unsigned int mirror = btrfs_io_bio(bio)->mirror_num; |
e6311f24 | 111 | int ret = 0; |
c8b97818 | 112 | |
4e4cbee9 | 113 | if (bio->bi_status) |
c8b97818 CM |
114 | cb->errors = 1; |
115 | ||
116 | /* if there are more bios still pending for this compressed | |
117 | * extent, just exit | |
118 | */ | |
a50299ae | 119 | if (!refcount_dec_and_test(&cb->pending_bios)) |
c8b97818 CM |
120 | goto out; |
121 | ||
cf1167d5 LB |
122 | /* |
123 | * Record the correct mirror_num in cb->orig_bio so that | |
124 | * read-repair can work properly. | |
125 | */ | |
126 | ASSERT(btrfs_io_bio(cb->orig_bio)); | |
127 | btrfs_io_bio(cb->orig_bio)->mirror_num = mirror; | |
128 | cb->mirror_num = mirror; | |
129 | ||
e6311f24 LB |
130 | /* |
131 | * Some IO in this cb have failed, just skip checksum as there | |
132 | * is no way it could be correct. | |
133 | */ | |
134 | if (cb->errors == 1) | |
135 | goto csum_failed; | |
136 | ||
d20f7043 | 137 | inode = cb->inode; |
f898ac6a | 138 | ret = check_compressed_csum(BTRFS_I(inode), cb, |
4f024f37 | 139 | (u64)bio->bi_iter.bi_sector << 9); |
d20f7043 CM |
140 | if (ret) |
141 | goto csum_failed; | |
142 | ||
c8b97818 CM |
143 | /* ok, we're the last bio for this extent, lets start |
144 | * the decompression. | |
145 | */ | |
8140dc30 AJ |
146 | ret = btrfs_decompress_bio(cb); |
147 | ||
d20f7043 | 148 | csum_failed: |
c8b97818 CM |
149 | if (ret) |
150 | cb->errors = 1; | |
151 | ||
152 | /* release the compressed pages */ | |
153 | index = 0; | |
154 | for (index = 0; index < cb->nr_pages; index++) { | |
155 | page = cb->compressed_pages[index]; | |
156 | page->mapping = NULL; | |
09cbfeaf | 157 | put_page(page); |
c8b97818 CM |
158 | } |
159 | ||
160 | /* do io completion on the original bio */ | |
771ed689 | 161 | if (cb->errors) { |
c8b97818 | 162 | bio_io_error(cb->orig_bio); |
d20f7043 | 163 | } else { |
2c30c71b KO |
164 | int i; |
165 | struct bio_vec *bvec; | |
d20f7043 CM |
166 | |
167 | /* | |
168 | * we have verified the checksum already, set page | |
169 | * checked so the end_io handlers know about it | |
170 | */ | |
c09abff8 | 171 | ASSERT(!bio_flagged(bio, BIO_CLONED)); |
2c30c71b | 172 | bio_for_each_segment_all(bvec, cb->orig_bio, i) |
d20f7043 | 173 | SetPageChecked(bvec->bv_page); |
2c30c71b | 174 | |
4246a0b6 | 175 | bio_endio(cb->orig_bio); |
d20f7043 | 176 | } |
c8b97818 CM |
177 | |
178 | /* finally free the cb struct */ | |
179 | kfree(cb->compressed_pages); | |
180 | kfree(cb); | |
181 | out: | |
182 | bio_put(bio); | |
183 | } | |
184 | ||
185 | /* | |
186 | * Clear the writeback bits on all of the file | |
187 | * pages for a compressed write | |
188 | */ | |
7bdcefc1 FM |
189 | static noinline void end_compressed_writeback(struct inode *inode, |
190 | const struct compressed_bio *cb) | |
c8b97818 | 191 | { |
09cbfeaf KS |
192 | unsigned long index = cb->start >> PAGE_SHIFT; |
193 | unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT; | |
c8b97818 CM |
194 | struct page *pages[16]; |
195 | unsigned long nr_pages = end_index - index + 1; | |
196 | int i; | |
197 | int ret; | |
198 | ||
7bdcefc1 FM |
199 | if (cb->errors) |
200 | mapping_set_error(inode->i_mapping, -EIO); | |
201 | ||
d397712b | 202 | while (nr_pages > 0) { |
c8b97818 | 203 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
204 | min_t(unsigned long, |
205 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
206 | if (ret == 0) { |
207 | nr_pages -= 1; | |
208 | index += 1; | |
209 | continue; | |
210 | } | |
211 | for (i = 0; i < ret; i++) { | |
7bdcefc1 FM |
212 | if (cb->errors) |
213 | SetPageError(pages[i]); | |
c8b97818 | 214 | end_page_writeback(pages[i]); |
09cbfeaf | 215 | put_page(pages[i]); |
c8b97818 CM |
216 | } |
217 | nr_pages -= ret; | |
218 | index += ret; | |
219 | } | |
220 | /* the inode may be gone now */ | |
c8b97818 CM |
221 | } |
222 | ||
223 | /* | |
224 | * do the cleanup once all the compressed pages hit the disk. | |
225 | * This will clear writeback on the file pages and free the compressed | |
226 | * pages. | |
227 | * | |
228 | * This also calls the writeback end hooks for the file pages so that | |
229 | * metadata and checksums can be updated in the file. | |
230 | */ | |
4246a0b6 | 231 | static void end_compressed_bio_write(struct bio *bio) |
c8b97818 CM |
232 | { |
233 | struct extent_io_tree *tree; | |
234 | struct compressed_bio *cb = bio->bi_private; | |
235 | struct inode *inode; | |
236 | struct page *page; | |
237 | unsigned long index; | |
238 | ||
4e4cbee9 | 239 | if (bio->bi_status) |
c8b97818 CM |
240 | cb->errors = 1; |
241 | ||
242 | /* if there are more bios still pending for this compressed | |
243 | * extent, just exit | |
244 | */ | |
a50299ae | 245 | if (!refcount_dec_and_test(&cb->pending_bios)) |
c8b97818 CM |
246 | goto out; |
247 | ||
248 | /* ok, we're the last bio for this extent, step one is to | |
249 | * call back into the FS and do all the end_io operations | |
250 | */ | |
251 | inode = cb->inode; | |
252 | tree = &BTRFS_I(inode)->io_tree; | |
70b99e69 | 253 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
c8b97818 CM |
254 | tree->ops->writepage_end_io_hook(cb->compressed_pages[0], |
255 | cb->start, | |
256 | cb->start + cb->len - 1, | |
7bdcefc1 | 257 | NULL, |
4e4cbee9 | 258 | bio->bi_status ? 0 : 1); |
70b99e69 | 259 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 | 260 | |
7bdcefc1 | 261 | end_compressed_writeback(inode, cb); |
c8b97818 CM |
262 | /* note, our inode could be gone now */ |
263 | ||
264 | /* | |
265 | * release the compressed pages, these came from alloc_page and | |
266 | * are not attached to the inode at all | |
267 | */ | |
268 | index = 0; | |
269 | for (index = 0; index < cb->nr_pages; index++) { | |
270 | page = cb->compressed_pages[index]; | |
271 | page->mapping = NULL; | |
09cbfeaf | 272 | put_page(page); |
c8b97818 CM |
273 | } |
274 | ||
275 | /* finally free the cb struct */ | |
276 | kfree(cb->compressed_pages); | |
277 | kfree(cb); | |
278 | out: | |
279 | bio_put(bio); | |
280 | } | |
281 | ||
282 | /* | |
283 | * worker function to build and submit bios for previously compressed pages. | |
284 | * The corresponding pages in the inode should be marked for writeback | |
285 | * and the compressed pages should have a reference on them for dropping | |
286 | * when the IO is complete. | |
287 | * | |
288 | * This also checksums the file bytes and gets things ready for | |
289 | * the end io hooks. | |
290 | */ | |
4e4cbee9 | 291 | blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, |
c8b97818 CM |
292 | unsigned long len, u64 disk_start, |
293 | unsigned long compressed_len, | |
294 | struct page **compressed_pages, | |
295 | unsigned long nr_pages) | |
296 | { | |
0b246afa | 297 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 | 298 | struct bio *bio = NULL; |
c8b97818 CM |
299 | struct compressed_bio *cb; |
300 | unsigned long bytes_left; | |
301 | struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; | |
306e16ce | 302 | int pg_index = 0; |
c8b97818 CM |
303 | struct page *page; |
304 | u64 first_byte = disk_start; | |
305 | struct block_device *bdev; | |
4e4cbee9 | 306 | blk_status_t ret; |
e55179b3 | 307 | int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; |
c8b97818 | 308 | |
09cbfeaf | 309 | WARN_ON(start & ((u64)PAGE_SIZE - 1)); |
2ff7e61e | 310 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
dac97e51 | 311 | if (!cb) |
4e4cbee9 | 312 | return BLK_STS_RESOURCE; |
a50299ae | 313 | refcount_set(&cb->pending_bios, 0); |
c8b97818 CM |
314 | cb->errors = 0; |
315 | cb->inode = inode; | |
316 | cb->start = start; | |
317 | cb->len = len; | |
d20f7043 | 318 | cb->mirror_num = 0; |
c8b97818 CM |
319 | cb->compressed_pages = compressed_pages; |
320 | cb->compressed_len = compressed_len; | |
321 | cb->orig_bio = NULL; | |
322 | cb->nr_pages = nr_pages; | |
323 | ||
0b246afa | 324 | bdev = fs_info->fs_devices->latest_bdev; |
c8b97818 | 325 | |
c821e7f3 | 326 | bio = btrfs_bio_alloc(bdev, first_byte); |
37226b21 | 327 | bio_set_op_attrs(bio, REQ_OP_WRITE, 0); |
c8b97818 CM |
328 | bio->bi_private = cb; |
329 | bio->bi_end_io = end_compressed_bio_write; | |
a50299ae | 330 | refcount_set(&cb->pending_bios, 1); |
c8b97818 CM |
331 | |
332 | /* create and submit bios for the compressed pages */ | |
333 | bytes_left = compressed_len; | |
306e16ce | 334 | for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { |
4e4cbee9 CH |
335 | int submit = 0; |
336 | ||
306e16ce | 337 | page = compressed_pages[pg_index]; |
c8b97818 | 338 | page->mapping = inode->i_mapping; |
4f024f37 | 339 | if (bio->bi_iter.bi_size) |
4e4cbee9 | 340 | submit = io_tree->ops->merge_bio_hook(page, 0, |
09cbfeaf | 341 | PAGE_SIZE, |
c8b97818 | 342 | bio, 0); |
c8b97818 | 343 | |
70b99e69 | 344 | page->mapping = NULL; |
4e4cbee9 | 345 | if (submit || bio_add_page(bio, page, PAGE_SIZE, 0) < |
09cbfeaf | 346 | PAGE_SIZE) { |
c8b97818 CM |
347 | bio_get(bio); |
348 | ||
af09abfe CM |
349 | /* |
350 | * inc the count before we submit the bio so | |
351 | * we know the end IO handler won't happen before | |
352 | * we inc the count. Otherwise, the cb might get | |
353 | * freed before we're done setting it up | |
354 | */ | |
a50299ae | 355 | refcount_inc(&cb->pending_bios); |
0b246afa JM |
356 | ret = btrfs_bio_wq_end_io(fs_info, bio, |
357 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 358 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 359 | |
e55179b3 | 360 | if (!skip_sum) { |
2ff7e61e | 361 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 362 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 363 | } |
d20f7043 | 364 | |
2ff7e61e | 365 | ret = btrfs_map_bio(fs_info, bio, 0, 1); |
f5daf2c7 | 366 | if (ret) { |
4e4cbee9 | 367 | bio->bi_status = ret; |
f5daf2c7 LB |
368 | bio_endio(bio); |
369 | } | |
c8b97818 CM |
370 | |
371 | bio_put(bio); | |
372 | ||
c821e7f3 | 373 | bio = btrfs_bio_alloc(bdev, first_byte); |
37226b21 | 374 | bio_set_op_attrs(bio, REQ_OP_WRITE, 0); |
c8b97818 CM |
375 | bio->bi_private = cb; |
376 | bio->bi_end_io = end_compressed_bio_write; | |
09cbfeaf | 377 | bio_add_page(bio, page, PAGE_SIZE, 0); |
c8b97818 | 378 | } |
09cbfeaf | 379 | if (bytes_left < PAGE_SIZE) { |
0b246afa | 380 | btrfs_info(fs_info, |
efe120a0 | 381 | "bytes left %lu compress len %lu nr %lu", |
cfbc246e CM |
382 | bytes_left, cb->compressed_len, cb->nr_pages); |
383 | } | |
09cbfeaf KS |
384 | bytes_left -= PAGE_SIZE; |
385 | first_byte += PAGE_SIZE; | |
771ed689 | 386 | cond_resched(); |
c8b97818 CM |
387 | } |
388 | bio_get(bio); | |
389 | ||
0b246afa | 390 | ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 391 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 392 | |
e55179b3 | 393 | if (!skip_sum) { |
2ff7e61e | 394 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 395 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 396 | } |
d20f7043 | 397 | |
2ff7e61e | 398 | ret = btrfs_map_bio(fs_info, bio, 0, 1); |
f5daf2c7 | 399 | if (ret) { |
4e4cbee9 | 400 | bio->bi_status = ret; |
f5daf2c7 LB |
401 | bio_endio(bio); |
402 | } | |
c8b97818 CM |
403 | |
404 | bio_put(bio); | |
405 | return 0; | |
406 | } | |
407 | ||
2a4d0c90 CH |
408 | static u64 bio_end_offset(struct bio *bio) |
409 | { | |
410 | struct bio_vec *last = &bio->bi_io_vec[bio->bi_vcnt - 1]; | |
411 | ||
412 | return page_offset(last->bv_page) + last->bv_len + last->bv_offset; | |
413 | } | |
414 | ||
771ed689 CM |
415 | static noinline int add_ra_bio_pages(struct inode *inode, |
416 | u64 compressed_end, | |
417 | struct compressed_bio *cb) | |
418 | { | |
419 | unsigned long end_index; | |
306e16ce | 420 | unsigned long pg_index; |
771ed689 CM |
421 | u64 last_offset; |
422 | u64 isize = i_size_read(inode); | |
423 | int ret; | |
424 | struct page *page; | |
425 | unsigned long nr_pages = 0; | |
426 | struct extent_map *em; | |
427 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
428 | struct extent_map_tree *em_tree; |
429 | struct extent_io_tree *tree; | |
430 | u64 end; | |
431 | int misses = 0; | |
432 | ||
2a4d0c90 | 433 | last_offset = bio_end_offset(cb->orig_bio); |
771ed689 CM |
434 | em_tree = &BTRFS_I(inode)->extent_tree; |
435 | tree = &BTRFS_I(inode)->io_tree; | |
436 | ||
437 | if (isize == 0) | |
438 | return 0; | |
439 | ||
09cbfeaf | 440 | end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; |
771ed689 | 441 | |
d397712b | 442 | while (last_offset < compressed_end) { |
09cbfeaf | 443 | pg_index = last_offset >> PAGE_SHIFT; |
771ed689 | 444 | |
306e16ce | 445 | if (pg_index > end_index) |
771ed689 CM |
446 | break; |
447 | ||
448 | rcu_read_lock(); | |
306e16ce | 449 | page = radix_tree_lookup(&mapping->page_tree, pg_index); |
771ed689 | 450 | rcu_read_unlock(); |
0cd6144a | 451 | if (page && !radix_tree_exceptional_entry(page)) { |
771ed689 CM |
452 | misses++; |
453 | if (misses > 4) | |
454 | break; | |
455 | goto next; | |
456 | } | |
457 | ||
c62d2555 MH |
458 | page = __page_cache_alloc(mapping_gfp_constraint(mapping, |
459 | ~__GFP_FS)); | |
771ed689 CM |
460 | if (!page) |
461 | break; | |
462 | ||
c62d2555 | 463 | if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) { |
09cbfeaf | 464 | put_page(page); |
771ed689 CM |
465 | goto next; |
466 | } | |
467 | ||
09cbfeaf | 468 | end = last_offset + PAGE_SIZE - 1; |
771ed689 CM |
469 | /* |
470 | * at this point, we have a locked page in the page cache | |
471 | * for these bytes in the file. But, we have to make | |
472 | * sure they map to this compressed extent on disk. | |
473 | */ | |
474 | set_page_extent_mapped(page); | |
d0082371 | 475 | lock_extent(tree, last_offset, end); |
890871be | 476 | read_lock(&em_tree->lock); |
771ed689 | 477 | em = lookup_extent_mapping(em_tree, last_offset, |
09cbfeaf | 478 | PAGE_SIZE); |
890871be | 479 | read_unlock(&em_tree->lock); |
771ed689 CM |
480 | |
481 | if (!em || last_offset < em->start || | |
09cbfeaf | 482 | (last_offset + PAGE_SIZE > extent_map_end(em)) || |
4f024f37 | 483 | (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) { |
771ed689 | 484 | free_extent_map(em); |
d0082371 | 485 | unlock_extent(tree, last_offset, end); |
771ed689 | 486 | unlock_page(page); |
09cbfeaf | 487 | put_page(page); |
771ed689 CM |
488 | break; |
489 | } | |
490 | free_extent_map(em); | |
491 | ||
492 | if (page->index == end_index) { | |
493 | char *userpage; | |
09cbfeaf | 494 | size_t zero_offset = isize & (PAGE_SIZE - 1); |
771ed689 CM |
495 | |
496 | if (zero_offset) { | |
497 | int zeros; | |
09cbfeaf | 498 | zeros = PAGE_SIZE - zero_offset; |
7ac687d9 | 499 | userpage = kmap_atomic(page); |
771ed689 CM |
500 | memset(userpage + zero_offset, 0, zeros); |
501 | flush_dcache_page(page); | |
7ac687d9 | 502 | kunmap_atomic(userpage); |
771ed689 CM |
503 | } |
504 | } | |
505 | ||
506 | ret = bio_add_page(cb->orig_bio, page, | |
09cbfeaf | 507 | PAGE_SIZE, 0); |
771ed689 | 508 | |
09cbfeaf | 509 | if (ret == PAGE_SIZE) { |
771ed689 | 510 | nr_pages++; |
09cbfeaf | 511 | put_page(page); |
771ed689 | 512 | } else { |
d0082371 | 513 | unlock_extent(tree, last_offset, end); |
771ed689 | 514 | unlock_page(page); |
09cbfeaf | 515 | put_page(page); |
771ed689 CM |
516 | break; |
517 | } | |
518 | next: | |
09cbfeaf | 519 | last_offset += PAGE_SIZE; |
771ed689 | 520 | } |
771ed689 CM |
521 | return 0; |
522 | } | |
523 | ||
c8b97818 CM |
524 | /* |
525 | * for a compressed read, the bio we get passed has all the inode pages | |
526 | * in it. We don't actually do IO on those pages but allocate new ones | |
527 | * to hold the compressed pages on disk. | |
528 | * | |
4f024f37 | 529 | * bio->bi_iter.bi_sector points to the compressed extent on disk |
c8b97818 | 530 | * bio->bi_io_vec points to all of the inode pages |
c8b97818 CM |
531 | * |
532 | * After the compressed pages are read, we copy the bytes into the | |
533 | * bio we were passed and then call the bio end_io calls | |
534 | */ | |
4e4cbee9 | 535 | blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, |
c8b97818 CM |
536 | int mirror_num, unsigned long bio_flags) |
537 | { | |
0b246afa | 538 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 CM |
539 | struct extent_io_tree *tree; |
540 | struct extent_map_tree *em_tree; | |
541 | struct compressed_bio *cb; | |
c8b97818 CM |
542 | unsigned long compressed_len; |
543 | unsigned long nr_pages; | |
306e16ce | 544 | unsigned long pg_index; |
c8b97818 CM |
545 | struct page *page; |
546 | struct block_device *bdev; | |
547 | struct bio *comp_bio; | |
4f024f37 | 548 | u64 cur_disk_byte = (u64)bio->bi_iter.bi_sector << 9; |
e04ca626 CM |
549 | u64 em_len; |
550 | u64 em_start; | |
c8b97818 | 551 | struct extent_map *em; |
4e4cbee9 | 552 | blk_status_t ret = BLK_STS_RESOURCE; |
15e3004a | 553 | int faili = 0; |
d20f7043 | 554 | u32 *sums; |
c8b97818 CM |
555 | |
556 | tree = &BTRFS_I(inode)->io_tree; | |
557 | em_tree = &BTRFS_I(inode)->extent_tree; | |
558 | ||
559 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 560 | read_lock(&em_tree->lock); |
c8b97818 CM |
561 | em = lookup_extent_mapping(em_tree, |
562 | page_offset(bio->bi_io_vec->bv_page), | |
09cbfeaf | 563 | PAGE_SIZE); |
890871be | 564 | read_unlock(&em_tree->lock); |
285190d9 | 565 | if (!em) |
4e4cbee9 | 566 | return BLK_STS_IOERR; |
c8b97818 | 567 | |
d20f7043 | 568 | compressed_len = em->block_len; |
2ff7e61e | 569 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
6b82ce8d | 570 | if (!cb) |
571 | goto out; | |
572 | ||
a50299ae | 573 | refcount_set(&cb->pending_bios, 0); |
c8b97818 CM |
574 | cb->errors = 0; |
575 | cb->inode = inode; | |
d20f7043 CM |
576 | cb->mirror_num = mirror_num; |
577 | sums = &cb->sums; | |
c8b97818 | 578 | |
ff5b7ee3 | 579 | cb->start = em->orig_start; |
e04ca626 CM |
580 | em_len = em->len; |
581 | em_start = em->start; | |
d20f7043 | 582 | |
c8b97818 | 583 | free_extent_map(em); |
e04ca626 | 584 | em = NULL; |
c8b97818 | 585 | |
81381053 | 586 | cb->len = bio->bi_iter.bi_size; |
c8b97818 | 587 | cb->compressed_len = compressed_len; |
261507a0 | 588 | cb->compress_type = extent_compress_type(bio_flags); |
c8b97818 CM |
589 | cb->orig_bio = bio; |
590 | ||
09cbfeaf | 591 | nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); |
31e818fe | 592 | cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *), |
c8b97818 | 593 | GFP_NOFS); |
6b82ce8d | 594 | if (!cb->compressed_pages) |
595 | goto fail1; | |
596 | ||
0b246afa | 597 | bdev = fs_info->fs_devices->latest_bdev; |
c8b97818 | 598 | |
306e16ce DS |
599 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
600 | cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | | |
c8b97818 | 601 | __GFP_HIGHMEM); |
15e3004a JB |
602 | if (!cb->compressed_pages[pg_index]) { |
603 | faili = pg_index - 1; | |
0e9350de | 604 | ret = BLK_STS_RESOURCE; |
6b82ce8d | 605 | goto fail2; |
15e3004a | 606 | } |
c8b97818 | 607 | } |
15e3004a | 608 | faili = nr_pages - 1; |
c8b97818 CM |
609 | cb->nr_pages = nr_pages; |
610 | ||
7f042a83 | 611 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 612 | |
771ed689 | 613 | /* include any pages we added in add_ra-bio_pages */ |
81381053 | 614 | cb->len = bio->bi_iter.bi_size; |
771ed689 | 615 | |
c821e7f3 | 616 | comp_bio = btrfs_bio_alloc(bdev, cur_disk_byte); |
37226b21 | 617 | bio_set_op_attrs (comp_bio, REQ_OP_READ, 0); |
c8b97818 CM |
618 | comp_bio->bi_private = cb; |
619 | comp_bio->bi_end_io = end_compressed_bio_read; | |
a50299ae | 620 | refcount_set(&cb->pending_bios, 1); |
c8b97818 | 621 | |
306e16ce | 622 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
4e4cbee9 CH |
623 | int submit = 0; |
624 | ||
306e16ce | 625 | page = cb->compressed_pages[pg_index]; |
c8b97818 | 626 | page->mapping = inode->i_mapping; |
09cbfeaf | 627 | page->index = em_start >> PAGE_SHIFT; |
d20f7043 | 628 | |
4f024f37 | 629 | if (comp_bio->bi_iter.bi_size) |
4e4cbee9 | 630 | submit = tree->ops->merge_bio_hook(page, 0, |
09cbfeaf | 631 | PAGE_SIZE, |
c8b97818 | 632 | comp_bio, 0); |
c8b97818 | 633 | |
70b99e69 | 634 | page->mapping = NULL; |
4e4cbee9 | 635 | if (submit || bio_add_page(comp_bio, page, PAGE_SIZE, 0) < |
09cbfeaf | 636 | PAGE_SIZE) { |
c8b97818 CM |
637 | bio_get(comp_bio); |
638 | ||
0b246afa JM |
639 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, |
640 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 641 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 642 | |
af09abfe CM |
643 | /* |
644 | * inc the count before we submit the bio so | |
645 | * we know the end IO handler won't happen before | |
646 | * we inc the count. Otherwise, the cb might get | |
647 | * freed before we're done setting it up | |
648 | */ | |
a50299ae | 649 | refcount_inc(&cb->pending_bios); |
af09abfe | 650 | |
6cbff00f | 651 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
2ff7e61e JM |
652 | ret = btrfs_lookup_bio_sums(inode, comp_bio, |
653 | sums); | |
79787eaa | 654 | BUG_ON(ret); /* -ENOMEM */ |
d20f7043 | 655 | } |
ed6078f7 | 656 | sums += DIV_ROUND_UP(comp_bio->bi_iter.bi_size, |
0b246afa | 657 | fs_info->sectorsize); |
d20f7043 | 658 | |
2ff7e61e | 659 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num, 0); |
4246a0b6 | 660 | if (ret) { |
4e4cbee9 | 661 | comp_bio->bi_status = ret; |
4246a0b6 CH |
662 | bio_endio(comp_bio); |
663 | } | |
c8b97818 CM |
664 | |
665 | bio_put(comp_bio); | |
666 | ||
c821e7f3 | 667 | comp_bio = btrfs_bio_alloc(bdev, cur_disk_byte); |
37226b21 | 668 | bio_set_op_attrs(comp_bio, REQ_OP_READ, 0); |
771ed689 CM |
669 | comp_bio->bi_private = cb; |
670 | comp_bio->bi_end_io = end_compressed_bio_read; | |
671 | ||
09cbfeaf | 672 | bio_add_page(comp_bio, page, PAGE_SIZE, 0); |
c8b97818 | 673 | } |
09cbfeaf | 674 | cur_disk_byte += PAGE_SIZE; |
c8b97818 CM |
675 | } |
676 | bio_get(comp_bio); | |
677 | ||
0b246afa | 678 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 679 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 680 | |
c2db1073 | 681 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
2ff7e61e | 682 | ret = btrfs_lookup_bio_sums(inode, comp_bio, sums); |
79787eaa | 683 | BUG_ON(ret); /* -ENOMEM */ |
c2db1073 | 684 | } |
d20f7043 | 685 | |
2ff7e61e | 686 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num, 0); |
4246a0b6 | 687 | if (ret) { |
4e4cbee9 | 688 | comp_bio->bi_status = ret; |
4246a0b6 CH |
689 | bio_endio(comp_bio); |
690 | } | |
c8b97818 CM |
691 | |
692 | bio_put(comp_bio); | |
693 | return 0; | |
6b82ce8d | 694 | |
695 | fail2: | |
15e3004a JB |
696 | while (faili >= 0) { |
697 | __free_page(cb->compressed_pages[faili]); | |
698 | faili--; | |
699 | } | |
6b82ce8d | 700 | |
701 | kfree(cb->compressed_pages); | |
702 | fail1: | |
703 | kfree(cb); | |
704 | out: | |
705 | free_extent_map(em); | |
706 | return ret; | |
c8b97818 | 707 | } |
261507a0 | 708 | |
d9187649 BL |
709 | static struct { |
710 | struct list_head idle_ws; | |
711 | spinlock_t ws_lock; | |
6ac10a6a DS |
712 | /* Number of free workspaces */ |
713 | int free_ws; | |
714 | /* Total number of allocated workspaces */ | |
715 | atomic_t total_ws; | |
716 | /* Waiters for a free workspace */ | |
d9187649 BL |
717 | wait_queue_head_t ws_wait; |
718 | } btrfs_comp_ws[BTRFS_COMPRESS_TYPES]; | |
261507a0 | 719 | |
e8c9f186 | 720 | static const struct btrfs_compress_op * const btrfs_compress_op[] = { |
261507a0 | 721 | &btrfs_zlib_compress, |
a6fa6fae | 722 | &btrfs_lzo_compress, |
5c1aab1d | 723 | &btrfs_zstd_compress, |
261507a0 LZ |
724 | }; |
725 | ||
143bede5 | 726 | void __init btrfs_init_compress(void) |
261507a0 LZ |
727 | { |
728 | int i; | |
729 | ||
730 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
f77dd0d6 DS |
731 | struct list_head *workspace; |
732 | ||
d9187649 BL |
733 | INIT_LIST_HEAD(&btrfs_comp_ws[i].idle_ws); |
734 | spin_lock_init(&btrfs_comp_ws[i].ws_lock); | |
6ac10a6a | 735 | atomic_set(&btrfs_comp_ws[i].total_ws, 0); |
d9187649 | 736 | init_waitqueue_head(&btrfs_comp_ws[i].ws_wait); |
f77dd0d6 DS |
737 | |
738 | /* | |
739 | * Preallocate one workspace for each compression type so | |
740 | * we can guarantee forward progress in the worst case | |
741 | */ | |
742 | workspace = btrfs_compress_op[i]->alloc_workspace(); | |
743 | if (IS_ERR(workspace)) { | |
62e85577 | 744 | pr_warn("BTRFS: cannot preallocate compression workspace, will try later\n"); |
f77dd0d6 DS |
745 | } else { |
746 | atomic_set(&btrfs_comp_ws[i].total_ws, 1); | |
747 | btrfs_comp_ws[i].free_ws = 1; | |
748 | list_add(workspace, &btrfs_comp_ws[i].idle_ws); | |
749 | } | |
261507a0 | 750 | } |
261507a0 LZ |
751 | } |
752 | ||
753 | /* | |
e721e49d DS |
754 | * This finds an available workspace or allocates a new one. |
755 | * If it's not possible to allocate a new one, waits until there's one. | |
756 | * Preallocation makes a forward progress guarantees and we do not return | |
757 | * errors. | |
261507a0 LZ |
758 | */ |
759 | static struct list_head *find_workspace(int type) | |
760 | { | |
761 | struct list_head *workspace; | |
762 | int cpus = num_online_cpus(); | |
763 | int idx = type - 1; | |
fe308533 | 764 | unsigned nofs_flag; |
261507a0 | 765 | |
d9187649 BL |
766 | struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; |
767 | spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; | |
6ac10a6a | 768 | atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; |
d9187649 | 769 | wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; |
6ac10a6a | 770 | int *free_ws = &btrfs_comp_ws[idx].free_ws; |
261507a0 | 771 | again: |
d9187649 BL |
772 | spin_lock(ws_lock); |
773 | if (!list_empty(idle_ws)) { | |
774 | workspace = idle_ws->next; | |
261507a0 | 775 | list_del(workspace); |
6ac10a6a | 776 | (*free_ws)--; |
d9187649 | 777 | spin_unlock(ws_lock); |
261507a0 LZ |
778 | return workspace; |
779 | ||
780 | } | |
6ac10a6a | 781 | if (atomic_read(total_ws) > cpus) { |
261507a0 LZ |
782 | DEFINE_WAIT(wait); |
783 | ||
d9187649 BL |
784 | spin_unlock(ws_lock); |
785 | prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE); | |
6ac10a6a | 786 | if (atomic_read(total_ws) > cpus && !*free_ws) |
261507a0 | 787 | schedule(); |
d9187649 | 788 | finish_wait(ws_wait, &wait); |
261507a0 LZ |
789 | goto again; |
790 | } | |
6ac10a6a | 791 | atomic_inc(total_ws); |
d9187649 | 792 | spin_unlock(ws_lock); |
261507a0 | 793 | |
fe308533 DS |
794 | /* |
795 | * Allocation helpers call vmalloc that can't use GFP_NOFS, so we have | |
796 | * to turn it off here because we might get called from the restricted | |
797 | * context of btrfs_compress_bio/btrfs_compress_pages | |
798 | */ | |
799 | nofs_flag = memalloc_nofs_save(); | |
261507a0 | 800 | workspace = btrfs_compress_op[idx]->alloc_workspace(); |
fe308533 DS |
801 | memalloc_nofs_restore(nofs_flag); |
802 | ||
261507a0 | 803 | if (IS_ERR(workspace)) { |
6ac10a6a | 804 | atomic_dec(total_ws); |
d9187649 | 805 | wake_up(ws_wait); |
e721e49d DS |
806 | |
807 | /* | |
808 | * Do not return the error but go back to waiting. There's a | |
809 | * workspace preallocated for each type and the compression | |
810 | * time is bounded so we get to a workspace eventually. This | |
811 | * makes our caller's life easier. | |
52356716 DS |
812 | * |
813 | * To prevent silent and low-probability deadlocks (when the | |
814 | * initial preallocation fails), check if there are any | |
815 | * workspaces at all. | |
e721e49d | 816 | */ |
52356716 DS |
817 | if (atomic_read(total_ws) == 0) { |
818 | static DEFINE_RATELIMIT_STATE(_rs, | |
819 | /* once per minute */ 60 * HZ, | |
820 | /* no burst */ 1); | |
821 | ||
822 | if (__ratelimit(&_rs)) { | |
ab8d0fc4 | 823 | pr_warn("BTRFS: no compression workspaces, low memory, retrying\n"); |
52356716 DS |
824 | } |
825 | } | |
e721e49d | 826 | goto again; |
261507a0 LZ |
827 | } |
828 | return workspace; | |
829 | } | |
830 | ||
831 | /* | |
832 | * put a workspace struct back on the list or free it if we have enough | |
833 | * idle ones sitting around | |
834 | */ | |
835 | static void free_workspace(int type, struct list_head *workspace) | |
836 | { | |
837 | int idx = type - 1; | |
d9187649 BL |
838 | struct list_head *idle_ws = &btrfs_comp_ws[idx].idle_ws; |
839 | spinlock_t *ws_lock = &btrfs_comp_ws[idx].ws_lock; | |
6ac10a6a | 840 | atomic_t *total_ws = &btrfs_comp_ws[idx].total_ws; |
d9187649 | 841 | wait_queue_head_t *ws_wait = &btrfs_comp_ws[idx].ws_wait; |
6ac10a6a | 842 | int *free_ws = &btrfs_comp_ws[idx].free_ws; |
d9187649 BL |
843 | |
844 | spin_lock(ws_lock); | |
26b28dce | 845 | if (*free_ws <= num_online_cpus()) { |
d9187649 | 846 | list_add(workspace, idle_ws); |
6ac10a6a | 847 | (*free_ws)++; |
d9187649 | 848 | spin_unlock(ws_lock); |
261507a0 LZ |
849 | goto wake; |
850 | } | |
d9187649 | 851 | spin_unlock(ws_lock); |
261507a0 LZ |
852 | |
853 | btrfs_compress_op[idx]->free_workspace(workspace); | |
6ac10a6a | 854 | atomic_dec(total_ws); |
261507a0 | 855 | wake: |
a83342aa DS |
856 | /* |
857 | * Make sure counter is updated before we wake up waiters. | |
858 | */ | |
66657b31 | 859 | smp_mb(); |
d9187649 BL |
860 | if (waitqueue_active(ws_wait)) |
861 | wake_up(ws_wait); | |
261507a0 LZ |
862 | } |
863 | ||
864 | /* | |
865 | * cleanup function for module exit | |
866 | */ | |
867 | static void free_workspaces(void) | |
868 | { | |
869 | struct list_head *workspace; | |
870 | int i; | |
871 | ||
872 | for (i = 0; i < BTRFS_COMPRESS_TYPES; i++) { | |
d9187649 BL |
873 | while (!list_empty(&btrfs_comp_ws[i].idle_ws)) { |
874 | workspace = btrfs_comp_ws[i].idle_ws.next; | |
261507a0 LZ |
875 | list_del(workspace); |
876 | btrfs_compress_op[i]->free_workspace(workspace); | |
6ac10a6a | 877 | atomic_dec(&btrfs_comp_ws[i].total_ws); |
261507a0 LZ |
878 | } |
879 | } | |
880 | } | |
881 | ||
882 | /* | |
38c31464 DS |
883 | * Given an address space and start and length, compress the bytes into @pages |
884 | * that are allocated on demand. | |
261507a0 | 885 | * |
4d3a800e DS |
886 | * @out_pages is an in/out parameter, holds maximum number of pages to allocate |
887 | * and returns number of actually allocated pages | |
261507a0 | 888 | * |
38c31464 DS |
889 | * @total_in is used to return the number of bytes actually read. It |
890 | * may be smaller than the input length if we had to exit early because we | |
261507a0 LZ |
891 | * ran out of room in the pages array or because we cross the |
892 | * max_out threshold. | |
893 | * | |
38c31464 DS |
894 | * @total_out is an in/out parameter, must be set to the input length and will |
895 | * be also used to return the total number of compressed bytes | |
261507a0 | 896 | * |
38c31464 | 897 | * @max_out tells us the max number of bytes that we're allowed to |
261507a0 LZ |
898 | * stuff into pages |
899 | */ | |
900 | int btrfs_compress_pages(int type, struct address_space *mapping, | |
38c31464 | 901 | u64 start, struct page **pages, |
261507a0 LZ |
902 | unsigned long *out_pages, |
903 | unsigned long *total_in, | |
e5d74902 | 904 | unsigned long *total_out) |
261507a0 LZ |
905 | { |
906 | struct list_head *workspace; | |
907 | int ret; | |
908 | ||
909 | workspace = find_workspace(type); | |
261507a0 LZ |
910 | |
911 | ret = btrfs_compress_op[type-1]->compress_pages(workspace, mapping, | |
38c31464 | 912 | start, pages, |
4d3a800e | 913 | out_pages, |
e5d74902 | 914 | total_in, total_out); |
261507a0 LZ |
915 | free_workspace(type, workspace); |
916 | return ret; | |
917 | } | |
918 | ||
919 | /* | |
920 | * pages_in is an array of pages with compressed data. | |
921 | * | |
922 | * disk_start is the starting logical offset of this array in the file | |
923 | * | |
974b1adc | 924 | * orig_bio contains the pages from the file that we want to decompress into |
261507a0 LZ |
925 | * |
926 | * srclen is the number of bytes in pages_in | |
927 | * | |
928 | * The basic idea is that we have a bio that was created by readpages. | |
929 | * The pages in the bio are for the uncompressed data, and they may not | |
930 | * be contiguous. They all correspond to the range of bytes covered by | |
931 | * the compressed extent. | |
932 | */ | |
8140dc30 | 933 | static int btrfs_decompress_bio(struct compressed_bio *cb) |
261507a0 LZ |
934 | { |
935 | struct list_head *workspace; | |
936 | int ret; | |
8140dc30 | 937 | int type = cb->compress_type; |
261507a0 LZ |
938 | |
939 | workspace = find_workspace(type); | |
e1ddce71 | 940 | ret = btrfs_compress_op[type - 1]->decompress_bio(workspace, cb); |
261507a0 | 941 | free_workspace(type, workspace); |
e1ddce71 | 942 | |
261507a0 LZ |
943 | return ret; |
944 | } | |
945 | ||
946 | /* | |
947 | * a less complex decompression routine. Our compressed data fits in a | |
948 | * single page, and we want to read a single page out of it. | |
949 | * start_byte tells us the offset into the compressed data we're interested in | |
950 | */ | |
951 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, | |
952 | unsigned long start_byte, size_t srclen, size_t destlen) | |
953 | { | |
954 | struct list_head *workspace; | |
955 | int ret; | |
956 | ||
957 | workspace = find_workspace(type); | |
261507a0 LZ |
958 | |
959 | ret = btrfs_compress_op[type-1]->decompress(workspace, data_in, | |
960 | dest_page, start_byte, | |
961 | srclen, destlen); | |
962 | ||
963 | free_workspace(type, workspace); | |
964 | return ret; | |
965 | } | |
966 | ||
8e4eef7a | 967 | void btrfs_exit_compress(void) |
261507a0 LZ |
968 | { |
969 | free_workspaces(); | |
970 | } | |
3a39c18d LZ |
971 | |
972 | /* | |
973 | * Copy uncompressed data from working buffer to pages. | |
974 | * | |
975 | * buf_start is the byte offset we're of the start of our workspace buffer. | |
976 | * | |
977 | * total_out is the last byte of the buffer | |
978 | */ | |
14a3357b | 979 | int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, |
3a39c18d | 980 | unsigned long total_out, u64 disk_start, |
974b1adc | 981 | struct bio *bio) |
3a39c18d LZ |
982 | { |
983 | unsigned long buf_offset; | |
984 | unsigned long current_buf_start; | |
985 | unsigned long start_byte; | |
6e78b3f7 | 986 | unsigned long prev_start_byte; |
3a39c18d LZ |
987 | unsigned long working_bytes = total_out - buf_start; |
988 | unsigned long bytes; | |
989 | char *kaddr; | |
974b1adc | 990 | struct bio_vec bvec = bio_iter_iovec(bio, bio->bi_iter); |
3a39c18d LZ |
991 | |
992 | /* | |
993 | * start byte is the first byte of the page we're currently | |
994 | * copying into relative to the start of the compressed data. | |
995 | */ | |
974b1adc | 996 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d LZ |
997 | |
998 | /* we haven't yet hit data corresponding to this page */ | |
999 | if (total_out <= start_byte) | |
1000 | return 1; | |
1001 | ||
1002 | /* | |
1003 | * the start of the data we care about is offset into | |
1004 | * the middle of our working buffer | |
1005 | */ | |
1006 | if (total_out > start_byte && buf_start < start_byte) { | |
1007 | buf_offset = start_byte - buf_start; | |
1008 | working_bytes -= buf_offset; | |
1009 | } else { | |
1010 | buf_offset = 0; | |
1011 | } | |
1012 | current_buf_start = buf_start; | |
1013 | ||
1014 | /* copy bytes from the working buffer into the pages */ | |
1015 | while (working_bytes > 0) { | |
974b1adc CH |
1016 | bytes = min_t(unsigned long, bvec.bv_len, |
1017 | PAGE_SIZE - buf_offset); | |
3a39c18d | 1018 | bytes = min(bytes, working_bytes); |
974b1adc CH |
1019 | |
1020 | kaddr = kmap_atomic(bvec.bv_page); | |
1021 | memcpy(kaddr + bvec.bv_offset, buf + buf_offset, bytes); | |
7ac687d9 | 1022 | kunmap_atomic(kaddr); |
974b1adc | 1023 | flush_dcache_page(bvec.bv_page); |
3a39c18d | 1024 | |
3a39c18d LZ |
1025 | buf_offset += bytes; |
1026 | working_bytes -= bytes; | |
1027 | current_buf_start += bytes; | |
1028 | ||
1029 | /* check if we need to pick another page */ | |
974b1adc CH |
1030 | bio_advance(bio, bytes); |
1031 | if (!bio->bi_iter.bi_size) | |
1032 | return 0; | |
1033 | bvec = bio_iter_iovec(bio, bio->bi_iter); | |
6e78b3f7 | 1034 | prev_start_byte = start_byte; |
974b1adc | 1035 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d | 1036 | |
974b1adc | 1037 | /* |
6e78b3f7 OS |
1038 | * We need to make sure we're only adjusting |
1039 | * our offset into compression working buffer when | |
1040 | * we're switching pages. Otherwise we can incorrectly | |
1041 | * keep copying when we were actually done. | |
974b1adc | 1042 | */ |
6e78b3f7 OS |
1043 | if (start_byte != prev_start_byte) { |
1044 | /* | |
1045 | * make sure our new page is covered by this | |
1046 | * working buffer | |
1047 | */ | |
1048 | if (total_out <= start_byte) | |
1049 | return 1; | |
3a39c18d | 1050 | |
6e78b3f7 OS |
1051 | /* |
1052 | * the next page in the biovec might not be adjacent | |
1053 | * to the last page, but it might still be found | |
1054 | * inside this working buffer. bump our offset pointer | |
1055 | */ | |
1056 | if (total_out > start_byte && | |
1057 | current_buf_start < start_byte) { | |
1058 | buf_offset = start_byte - buf_start; | |
1059 | working_bytes = total_out - start_byte; | |
1060 | current_buf_start = buf_start + buf_offset; | |
1061 | } | |
3a39c18d LZ |
1062 | } |
1063 | } | |
1064 | ||
1065 | return 1; | |
1066 | } | |
c2fcdcdf TT |
1067 | |
1068 | /* | |
1069 | * Compression heuristic. | |
1070 | * | |
1071 | * For now is's a naive and optimistic 'return true', we'll extend the logic to | |
1072 | * quickly (compared to direct compression) detect data characteristics | |
1073 | * (compressible/uncompressible) to avoid wasting CPU time on uncompressible | |
1074 | * data. | |
1075 | * | |
1076 | * The following types of analysis can be performed: | |
1077 | * - detect mostly zero data | |
1078 | * - detect data with low "byte set" size (text, etc) | |
1079 | * - detect data with low/high "core byte" set | |
1080 | * | |
1081 | * Return non-zero if the compression should be done, 0 otherwise. | |
1082 | */ | |
1083 | int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) | |
1084 | { | |
1085 | u64 index = start >> PAGE_SHIFT; | |
1086 | u64 end_index = end >> PAGE_SHIFT; | |
1087 | struct page *page; | |
1088 | int ret = 1; | |
1089 | ||
1090 | while (index <= end_index) { | |
1091 | page = find_get_page(inode->i_mapping, index); | |
1092 | kmap(page); | |
1093 | kunmap(page); | |
1094 | put_page(page); | |
1095 | index++; | |
1096 | } | |
1097 | ||
1098 | return ret; | |
1099 | } |