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c1d7c514 | 1 | // SPDX-License-Identifier: GPL-2.0 |
c8b97818 CM |
2 | /* |
3 | * Copyright (C) 2008 Oracle. All rights reserved. | |
c8b97818 CM |
4 | */ |
5 | ||
6 | #include <linux/kernel.h> | |
7 | #include <linux/bio.h> | |
c8b97818 CM |
8 | #include <linux/file.h> |
9 | #include <linux/fs.h> | |
10 | #include <linux/pagemap.h> | |
11 | #include <linux/highmem.h> | |
12 | #include <linux/time.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/string.h> | |
c8b97818 | 15 | #include <linux/backing-dev.h> |
c8b97818 | 16 | #include <linux/writeback.h> |
5a0e3ad6 | 17 | #include <linux/slab.h> |
fe308533 | 18 | #include <linux/sched/mm.h> |
19562430 | 19 | #include <linux/log2.h> |
d5178578 | 20 | #include <crypto/hash.h> |
602cbe91 | 21 | #include "misc.h" |
c8b97818 CM |
22 | #include "ctree.h" |
23 | #include "disk-io.h" | |
24 | #include "transaction.h" | |
25 | #include "btrfs_inode.h" | |
26 | #include "volumes.h" | |
27 | #include "ordered-data.h" | |
c8b97818 CM |
28 | #include "compression.h" |
29 | #include "extent_io.h" | |
30 | #include "extent_map.h" | |
31 | ||
e128f9c3 DS |
32 | static const char* const btrfs_compress_types[] = { "", "zlib", "lzo", "zstd" }; |
33 | ||
34 | const char* btrfs_compress_type2str(enum btrfs_compression_type type) | |
35 | { | |
36 | switch (type) { | |
37 | case BTRFS_COMPRESS_ZLIB: | |
38 | case BTRFS_COMPRESS_LZO: | |
39 | case BTRFS_COMPRESS_ZSTD: | |
40 | case BTRFS_COMPRESS_NONE: | |
41 | return btrfs_compress_types[type]; | |
42 | } | |
43 | ||
44 | return NULL; | |
45 | } | |
46 | ||
aa53e3bf JT |
47 | bool btrfs_compress_is_valid_type(const char *str, size_t len) |
48 | { | |
49 | int i; | |
50 | ||
51 | for (i = 1; i < ARRAY_SIZE(btrfs_compress_types); i++) { | |
52 | size_t comp_len = strlen(btrfs_compress_types[i]); | |
53 | ||
54 | if (len < comp_len) | |
55 | continue; | |
56 | ||
57 | if (!strncmp(btrfs_compress_types[i], str, comp_len)) | |
58 | return true; | |
59 | } | |
60 | return false; | |
61 | } | |
62 | ||
8140dc30 | 63 | static int btrfs_decompress_bio(struct compressed_bio *cb); |
48a3b636 | 64 | |
2ff7e61e | 65 | static inline int compressed_bio_size(struct btrfs_fs_info *fs_info, |
d20f7043 CM |
66 | unsigned long disk_size) |
67 | { | |
0b246afa | 68 | u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
6c41761f | 69 | |
d20f7043 | 70 | return sizeof(struct compressed_bio) + |
0b246afa | 71 | (DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * csum_size; |
d20f7043 CM |
72 | } |
73 | ||
f898ac6a | 74 | static int check_compressed_csum(struct btrfs_inode *inode, |
d20f7043 CM |
75 | struct compressed_bio *cb, |
76 | u64 disk_start) | |
77 | { | |
10fe6ca8 | 78 | struct btrfs_fs_info *fs_info = inode->root->fs_info; |
d5178578 | 79 | SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); |
10fe6ca8 | 80 | const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
d20f7043 | 81 | int ret; |
d20f7043 CM |
82 | struct page *page; |
83 | unsigned long i; | |
84 | char *kaddr; | |
d5178578 | 85 | u8 csum[BTRFS_CSUM_SIZE]; |
10fe6ca8 | 86 | u8 *cb_sum = cb->sums; |
d20f7043 | 87 | |
f898ac6a | 88 | if (inode->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
89 | return 0; |
90 | ||
d5178578 JT |
91 | shash->tfm = fs_info->csum_shash; |
92 | ||
d20f7043 CM |
93 | for (i = 0; i < cb->nr_pages; i++) { |
94 | page = cb->compressed_pages[i]; | |
d20f7043 | 95 | |
d5178578 | 96 | crypto_shash_init(shash); |
7ac687d9 | 97 | kaddr = kmap_atomic(page); |
d5178578 | 98 | crypto_shash_update(shash, kaddr, PAGE_SIZE); |
7ac687d9 | 99 | kunmap_atomic(kaddr); |
d5178578 | 100 | crypto_shash_final(shash, (u8 *)&csum); |
d20f7043 | 101 | |
10fe6ca8 | 102 | if (memcmp(&csum, cb_sum, csum_size)) { |
d5178578 | 103 | btrfs_print_data_csum_error(inode, disk_start, |
ea41d6b2 | 104 | csum, cb_sum, cb->mirror_num); |
d20f7043 CM |
105 | ret = -EIO; |
106 | goto fail; | |
107 | } | |
10fe6ca8 | 108 | cb_sum += csum_size; |
d20f7043 CM |
109 | |
110 | } | |
111 | ret = 0; | |
112 | fail: | |
113 | return ret; | |
114 | } | |
115 | ||
c8b97818 CM |
116 | /* when we finish reading compressed pages from the disk, we |
117 | * decompress them and then run the bio end_io routines on the | |
118 | * decompressed pages (in the inode address space). | |
119 | * | |
120 | * This allows the checksumming and other IO error handling routines | |
121 | * to work normally | |
122 | * | |
123 | * The compressed pages are freed here, and it must be run | |
124 | * in process context | |
125 | */ | |
4246a0b6 | 126 | static void end_compressed_bio_read(struct bio *bio) |
c8b97818 | 127 | { |
c8b97818 CM |
128 | struct compressed_bio *cb = bio->bi_private; |
129 | struct inode *inode; | |
130 | struct page *page; | |
131 | unsigned long index; | |
cf1167d5 | 132 | unsigned int mirror = btrfs_io_bio(bio)->mirror_num; |
e6311f24 | 133 | int ret = 0; |
c8b97818 | 134 | |
4e4cbee9 | 135 | if (bio->bi_status) |
c8b97818 CM |
136 | cb->errors = 1; |
137 | ||
138 | /* if there are more bios still pending for this compressed | |
139 | * extent, just exit | |
140 | */ | |
a50299ae | 141 | if (!refcount_dec_and_test(&cb->pending_bios)) |
c8b97818 CM |
142 | goto out; |
143 | ||
cf1167d5 LB |
144 | /* |
145 | * Record the correct mirror_num in cb->orig_bio so that | |
146 | * read-repair can work properly. | |
147 | */ | |
148 | ASSERT(btrfs_io_bio(cb->orig_bio)); | |
149 | btrfs_io_bio(cb->orig_bio)->mirror_num = mirror; | |
150 | cb->mirror_num = mirror; | |
151 | ||
e6311f24 LB |
152 | /* |
153 | * Some IO in this cb have failed, just skip checksum as there | |
154 | * is no way it could be correct. | |
155 | */ | |
156 | if (cb->errors == 1) | |
157 | goto csum_failed; | |
158 | ||
d20f7043 | 159 | inode = cb->inode; |
f898ac6a | 160 | ret = check_compressed_csum(BTRFS_I(inode), cb, |
4f024f37 | 161 | (u64)bio->bi_iter.bi_sector << 9); |
d20f7043 CM |
162 | if (ret) |
163 | goto csum_failed; | |
164 | ||
c8b97818 CM |
165 | /* ok, we're the last bio for this extent, lets start |
166 | * the decompression. | |
167 | */ | |
8140dc30 AJ |
168 | ret = btrfs_decompress_bio(cb); |
169 | ||
d20f7043 | 170 | csum_failed: |
c8b97818 CM |
171 | if (ret) |
172 | cb->errors = 1; | |
173 | ||
174 | /* release the compressed pages */ | |
175 | index = 0; | |
176 | for (index = 0; index < cb->nr_pages; index++) { | |
177 | page = cb->compressed_pages[index]; | |
178 | page->mapping = NULL; | |
09cbfeaf | 179 | put_page(page); |
c8b97818 CM |
180 | } |
181 | ||
182 | /* do io completion on the original bio */ | |
771ed689 | 183 | if (cb->errors) { |
c8b97818 | 184 | bio_io_error(cb->orig_bio); |
d20f7043 | 185 | } else { |
2c30c71b | 186 | struct bio_vec *bvec; |
6dc4f100 | 187 | struct bvec_iter_all iter_all; |
d20f7043 CM |
188 | |
189 | /* | |
190 | * we have verified the checksum already, set page | |
191 | * checked so the end_io handlers know about it | |
192 | */ | |
c09abff8 | 193 | ASSERT(!bio_flagged(bio, BIO_CLONED)); |
2b070cfe | 194 | bio_for_each_segment_all(bvec, cb->orig_bio, iter_all) |
d20f7043 | 195 | SetPageChecked(bvec->bv_page); |
2c30c71b | 196 | |
4246a0b6 | 197 | bio_endio(cb->orig_bio); |
d20f7043 | 198 | } |
c8b97818 CM |
199 | |
200 | /* finally free the cb struct */ | |
201 | kfree(cb->compressed_pages); | |
202 | kfree(cb); | |
203 | out: | |
204 | bio_put(bio); | |
205 | } | |
206 | ||
207 | /* | |
208 | * Clear the writeback bits on all of the file | |
209 | * pages for a compressed write | |
210 | */ | |
7bdcefc1 FM |
211 | static noinline void end_compressed_writeback(struct inode *inode, |
212 | const struct compressed_bio *cb) | |
c8b97818 | 213 | { |
09cbfeaf KS |
214 | unsigned long index = cb->start >> PAGE_SHIFT; |
215 | unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT; | |
c8b97818 CM |
216 | struct page *pages[16]; |
217 | unsigned long nr_pages = end_index - index + 1; | |
218 | int i; | |
219 | int ret; | |
220 | ||
7bdcefc1 FM |
221 | if (cb->errors) |
222 | mapping_set_error(inode->i_mapping, -EIO); | |
223 | ||
d397712b | 224 | while (nr_pages > 0) { |
c8b97818 | 225 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
226 | min_t(unsigned long, |
227 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
228 | if (ret == 0) { |
229 | nr_pages -= 1; | |
230 | index += 1; | |
231 | continue; | |
232 | } | |
233 | for (i = 0; i < ret; i++) { | |
7bdcefc1 FM |
234 | if (cb->errors) |
235 | SetPageError(pages[i]); | |
c8b97818 | 236 | end_page_writeback(pages[i]); |
09cbfeaf | 237 | put_page(pages[i]); |
c8b97818 CM |
238 | } |
239 | nr_pages -= ret; | |
240 | index += ret; | |
241 | } | |
242 | /* the inode may be gone now */ | |
c8b97818 CM |
243 | } |
244 | ||
245 | /* | |
246 | * do the cleanup once all the compressed pages hit the disk. | |
247 | * This will clear writeback on the file pages and free the compressed | |
248 | * pages. | |
249 | * | |
250 | * This also calls the writeback end hooks for the file pages so that | |
251 | * metadata and checksums can be updated in the file. | |
252 | */ | |
4246a0b6 | 253 | static void end_compressed_bio_write(struct bio *bio) |
c8b97818 | 254 | { |
c8b97818 CM |
255 | struct compressed_bio *cb = bio->bi_private; |
256 | struct inode *inode; | |
257 | struct page *page; | |
258 | unsigned long index; | |
259 | ||
4e4cbee9 | 260 | if (bio->bi_status) |
c8b97818 CM |
261 | cb->errors = 1; |
262 | ||
263 | /* if there are more bios still pending for this compressed | |
264 | * extent, just exit | |
265 | */ | |
a50299ae | 266 | if (!refcount_dec_and_test(&cb->pending_bios)) |
c8b97818 CM |
267 | goto out; |
268 | ||
269 | /* ok, we're the last bio for this extent, step one is to | |
270 | * call back into the FS and do all the end_io operations | |
271 | */ | |
272 | inode = cb->inode; | |
70b99e69 | 273 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
7087a9d8 | 274 | btrfs_writepage_endio_finish_ordered(cb->compressed_pages[0], |
c629732d | 275 | cb->start, cb->start + cb->len - 1, |
6a8d2136 | 276 | bio->bi_status == BLK_STS_OK); |
70b99e69 | 277 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 | 278 | |
7bdcefc1 | 279 | end_compressed_writeback(inode, cb); |
c8b97818 CM |
280 | /* note, our inode could be gone now */ |
281 | ||
282 | /* | |
283 | * release the compressed pages, these came from alloc_page and | |
284 | * are not attached to the inode at all | |
285 | */ | |
286 | index = 0; | |
287 | for (index = 0; index < cb->nr_pages; index++) { | |
288 | page = cb->compressed_pages[index]; | |
289 | page->mapping = NULL; | |
09cbfeaf | 290 | put_page(page); |
c8b97818 CM |
291 | } |
292 | ||
293 | /* finally free the cb struct */ | |
294 | kfree(cb->compressed_pages); | |
295 | kfree(cb); | |
296 | out: | |
297 | bio_put(bio); | |
298 | } | |
299 | ||
300 | /* | |
301 | * worker function to build and submit bios for previously compressed pages. | |
302 | * The corresponding pages in the inode should be marked for writeback | |
303 | * and the compressed pages should have a reference on them for dropping | |
304 | * when the IO is complete. | |
305 | * | |
306 | * This also checksums the file bytes and gets things ready for | |
307 | * the end io hooks. | |
308 | */ | |
4e4cbee9 | 309 | blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start, |
c8b97818 CM |
310 | unsigned long len, u64 disk_start, |
311 | unsigned long compressed_len, | |
312 | struct page **compressed_pages, | |
f82b7359 LB |
313 | unsigned long nr_pages, |
314 | unsigned int write_flags) | |
c8b97818 | 315 | { |
0b246afa | 316 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 | 317 | struct bio *bio = NULL; |
c8b97818 CM |
318 | struct compressed_bio *cb; |
319 | unsigned long bytes_left; | |
306e16ce | 320 | int pg_index = 0; |
c8b97818 CM |
321 | struct page *page; |
322 | u64 first_byte = disk_start; | |
323 | struct block_device *bdev; | |
4e4cbee9 | 324 | blk_status_t ret; |
e55179b3 | 325 | int skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM; |
c8b97818 | 326 | |
fdb1e121 | 327 | WARN_ON(!PAGE_ALIGNED(start)); |
2ff7e61e | 328 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
dac97e51 | 329 | if (!cb) |
4e4cbee9 | 330 | return BLK_STS_RESOURCE; |
a50299ae | 331 | refcount_set(&cb->pending_bios, 0); |
c8b97818 CM |
332 | cb->errors = 0; |
333 | cb->inode = inode; | |
334 | cb->start = start; | |
335 | cb->len = len; | |
d20f7043 | 336 | cb->mirror_num = 0; |
c8b97818 CM |
337 | cb->compressed_pages = compressed_pages; |
338 | cb->compressed_len = compressed_len; | |
339 | cb->orig_bio = NULL; | |
340 | cb->nr_pages = nr_pages; | |
341 | ||
0b246afa | 342 | bdev = fs_info->fs_devices->latest_bdev; |
c8b97818 | 343 | |
e749af44 DS |
344 | bio = btrfs_bio_alloc(first_byte); |
345 | bio_set_dev(bio, bdev); | |
f82b7359 | 346 | bio->bi_opf = REQ_OP_WRITE | write_flags; |
c8b97818 CM |
347 | bio->bi_private = cb; |
348 | bio->bi_end_io = end_compressed_bio_write; | |
a50299ae | 349 | refcount_set(&cb->pending_bios, 1); |
c8b97818 CM |
350 | |
351 | /* create and submit bios for the compressed pages */ | |
352 | bytes_left = compressed_len; | |
306e16ce | 353 | for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { |
4e4cbee9 CH |
354 | int submit = 0; |
355 | ||
306e16ce | 356 | page = compressed_pages[pg_index]; |
c8b97818 | 357 | page->mapping = inode->i_mapping; |
4f024f37 | 358 | if (bio->bi_iter.bi_size) |
da12fe54 NB |
359 | submit = btrfs_bio_fits_in_stripe(page, PAGE_SIZE, bio, |
360 | 0); | |
c8b97818 | 361 | |
70b99e69 | 362 | page->mapping = NULL; |
4e4cbee9 | 363 | if (submit || bio_add_page(bio, page, PAGE_SIZE, 0) < |
09cbfeaf | 364 | PAGE_SIZE) { |
af09abfe CM |
365 | /* |
366 | * inc the count before we submit the bio so | |
367 | * we know the end IO handler won't happen before | |
368 | * we inc the count. Otherwise, the cb might get | |
369 | * freed before we're done setting it up | |
370 | */ | |
a50299ae | 371 | refcount_inc(&cb->pending_bios); |
0b246afa JM |
372 | ret = btrfs_bio_wq_end_io(fs_info, bio, |
373 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 374 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 375 | |
e55179b3 | 376 | if (!skip_sum) { |
2ff7e61e | 377 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 378 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 379 | } |
d20f7043 | 380 | |
2ff7e61e | 381 | ret = btrfs_map_bio(fs_info, bio, 0, 1); |
f5daf2c7 | 382 | if (ret) { |
4e4cbee9 | 383 | bio->bi_status = ret; |
f5daf2c7 LB |
384 | bio_endio(bio); |
385 | } | |
c8b97818 | 386 | |
e749af44 DS |
387 | bio = btrfs_bio_alloc(first_byte); |
388 | bio_set_dev(bio, bdev); | |
f82b7359 | 389 | bio->bi_opf = REQ_OP_WRITE | write_flags; |
c8b97818 CM |
390 | bio->bi_private = cb; |
391 | bio->bi_end_io = end_compressed_bio_write; | |
09cbfeaf | 392 | bio_add_page(bio, page, PAGE_SIZE, 0); |
c8b97818 | 393 | } |
09cbfeaf | 394 | if (bytes_left < PAGE_SIZE) { |
0b246afa | 395 | btrfs_info(fs_info, |
efe120a0 | 396 | "bytes left %lu compress len %lu nr %lu", |
cfbc246e CM |
397 | bytes_left, cb->compressed_len, cb->nr_pages); |
398 | } | |
09cbfeaf KS |
399 | bytes_left -= PAGE_SIZE; |
400 | first_byte += PAGE_SIZE; | |
771ed689 | 401 | cond_resched(); |
c8b97818 | 402 | } |
c8b97818 | 403 | |
0b246afa | 404 | ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 405 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 406 | |
e55179b3 | 407 | if (!skip_sum) { |
2ff7e61e | 408 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 409 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 410 | } |
d20f7043 | 411 | |
2ff7e61e | 412 | ret = btrfs_map_bio(fs_info, bio, 0, 1); |
f5daf2c7 | 413 | if (ret) { |
4e4cbee9 | 414 | bio->bi_status = ret; |
f5daf2c7 LB |
415 | bio_endio(bio); |
416 | } | |
c8b97818 | 417 | |
c8b97818 CM |
418 | return 0; |
419 | } | |
420 | ||
2a4d0c90 CH |
421 | static u64 bio_end_offset(struct bio *bio) |
422 | { | |
c45a8f2d | 423 | struct bio_vec *last = bio_last_bvec_all(bio); |
2a4d0c90 CH |
424 | |
425 | return page_offset(last->bv_page) + last->bv_len + last->bv_offset; | |
426 | } | |
427 | ||
771ed689 CM |
428 | static noinline int add_ra_bio_pages(struct inode *inode, |
429 | u64 compressed_end, | |
430 | struct compressed_bio *cb) | |
431 | { | |
432 | unsigned long end_index; | |
306e16ce | 433 | unsigned long pg_index; |
771ed689 CM |
434 | u64 last_offset; |
435 | u64 isize = i_size_read(inode); | |
436 | int ret; | |
437 | struct page *page; | |
438 | unsigned long nr_pages = 0; | |
439 | struct extent_map *em; | |
440 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
441 | struct extent_map_tree *em_tree; |
442 | struct extent_io_tree *tree; | |
443 | u64 end; | |
444 | int misses = 0; | |
445 | ||
2a4d0c90 | 446 | last_offset = bio_end_offset(cb->orig_bio); |
771ed689 CM |
447 | em_tree = &BTRFS_I(inode)->extent_tree; |
448 | tree = &BTRFS_I(inode)->io_tree; | |
449 | ||
450 | if (isize == 0) | |
451 | return 0; | |
452 | ||
09cbfeaf | 453 | end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; |
771ed689 | 454 | |
d397712b | 455 | while (last_offset < compressed_end) { |
09cbfeaf | 456 | pg_index = last_offset >> PAGE_SHIFT; |
771ed689 | 457 | |
306e16ce | 458 | if (pg_index > end_index) |
771ed689 CM |
459 | break; |
460 | ||
0a943c65 | 461 | page = xa_load(&mapping->i_pages, pg_index); |
3159f943 | 462 | if (page && !xa_is_value(page)) { |
771ed689 CM |
463 | misses++; |
464 | if (misses > 4) | |
465 | break; | |
466 | goto next; | |
467 | } | |
468 | ||
c62d2555 MH |
469 | page = __page_cache_alloc(mapping_gfp_constraint(mapping, |
470 | ~__GFP_FS)); | |
771ed689 CM |
471 | if (!page) |
472 | break; | |
473 | ||
c62d2555 | 474 | if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) { |
09cbfeaf | 475 | put_page(page); |
771ed689 CM |
476 | goto next; |
477 | } | |
478 | ||
09cbfeaf | 479 | end = last_offset + PAGE_SIZE - 1; |
771ed689 CM |
480 | /* |
481 | * at this point, we have a locked page in the page cache | |
482 | * for these bytes in the file. But, we have to make | |
483 | * sure they map to this compressed extent on disk. | |
484 | */ | |
485 | set_page_extent_mapped(page); | |
d0082371 | 486 | lock_extent(tree, last_offset, end); |
890871be | 487 | read_lock(&em_tree->lock); |
771ed689 | 488 | em = lookup_extent_mapping(em_tree, last_offset, |
09cbfeaf | 489 | PAGE_SIZE); |
890871be | 490 | read_unlock(&em_tree->lock); |
771ed689 CM |
491 | |
492 | if (!em || last_offset < em->start || | |
09cbfeaf | 493 | (last_offset + PAGE_SIZE > extent_map_end(em)) || |
4f024f37 | 494 | (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) { |
771ed689 | 495 | free_extent_map(em); |
d0082371 | 496 | unlock_extent(tree, last_offset, end); |
771ed689 | 497 | unlock_page(page); |
09cbfeaf | 498 | put_page(page); |
771ed689 CM |
499 | break; |
500 | } | |
501 | free_extent_map(em); | |
502 | ||
503 | if (page->index == end_index) { | |
504 | char *userpage; | |
7073017a | 505 | size_t zero_offset = offset_in_page(isize); |
771ed689 CM |
506 | |
507 | if (zero_offset) { | |
508 | int zeros; | |
09cbfeaf | 509 | zeros = PAGE_SIZE - zero_offset; |
7ac687d9 | 510 | userpage = kmap_atomic(page); |
771ed689 CM |
511 | memset(userpage + zero_offset, 0, zeros); |
512 | flush_dcache_page(page); | |
7ac687d9 | 513 | kunmap_atomic(userpage); |
771ed689 CM |
514 | } |
515 | } | |
516 | ||
517 | ret = bio_add_page(cb->orig_bio, page, | |
09cbfeaf | 518 | PAGE_SIZE, 0); |
771ed689 | 519 | |
09cbfeaf | 520 | if (ret == PAGE_SIZE) { |
771ed689 | 521 | nr_pages++; |
09cbfeaf | 522 | put_page(page); |
771ed689 | 523 | } else { |
d0082371 | 524 | unlock_extent(tree, last_offset, end); |
771ed689 | 525 | unlock_page(page); |
09cbfeaf | 526 | put_page(page); |
771ed689 CM |
527 | break; |
528 | } | |
529 | next: | |
09cbfeaf | 530 | last_offset += PAGE_SIZE; |
771ed689 | 531 | } |
771ed689 CM |
532 | return 0; |
533 | } | |
534 | ||
c8b97818 CM |
535 | /* |
536 | * for a compressed read, the bio we get passed has all the inode pages | |
537 | * in it. We don't actually do IO on those pages but allocate new ones | |
538 | * to hold the compressed pages on disk. | |
539 | * | |
4f024f37 | 540 | * bio->bi_iter.bi_sector points to the compressed extent on disk |
c8b97818 | 541 | * bio->bi_io_vec points to all of the inode pages |
c8b97818 CM |
542 | * |
543 | * After the compressed pages are read, we copy the bytes into the | |
544 | * bio we were passed and then call the bio end_io calls | |
545 | */ | |
4e4cbee9 | 546 | blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, |
c8b97818 CM |
547 | int mirror_num, unsigned long bio_flags) |
548 | { | |
0b246afa | 549 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 CM |
550 | struct extent_map_tree *em_tree; |
551 | struct compressed_bio *cb; | |
c8b97818 CM |
552 | unsigned long compressed_len; |
553 | unsigned long nr_pages; | |
306e16ce | 554 | unsigned long pg_index; |
c8b97818 CM |
555 | struct page *page; |
556 | struct block_device *bdev; | |
557 | struct bio *comp_bio; | |
4f024f37 | 558 | u64 cur_disk_byte = (u64)bio->bi_iter.bi_sector << 9; |
e04ca626 CM |
559 | u64 em_len; |
560 | u64 em_start; | |
c8b97818 | 561 | struct extent_map *em; |
4e4cbee9 | 562 | blk_status_t ret = BLK_STS_RESOURCE; |
15e3004a | 563 | int faili = 0; |
10fe6ca8 JT |
564 | const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
565 | u8 *sums; | |
c8b97818 | 566 | |
c8b97818 CM |
567 | em_tree = &BTRFS_I(inode)->extent_tree; |
568 | ||
569 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 570 | read_lock(&em_tree->lock); |
c8b97818 | 571 | em = lookup_extent_mapping(em_tree, |
263663cd | 572 | page_offset(bio_first_page_all(bio)), |
09cbfeaf | 573 | PAGE_SIZE); |
890871be | 574 | read_unlock(&em_tree->lock); |
285190d9 | 575 | if (!em) |
4e4cbee9 | 576 | return BLK_STS_IOERR; |
c8b97818 | 577 | |
d20f7043 | 578 | compressed_len = em->block_len; |
2ff7e61e | 579 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
6b82ce8d | 580 | if (!cb) |
581 | goto out; | |
582 | ||
a50299ae | 583 | refcount_set(&cb->pending_bios, 0); |
c8b97818 CM |
584 | cb->errors = 0; |
585 | cb->inode = inode; | |
d20f7043 | 586 | cb->mirror_num = mirror_num; |
10fe6ca8 | 587 | sums = cb->sums; |
c8b97818 | 588 | |
ff5b7ee3 | 589 | cb->start = em->orig_start; |
e04ca626 CM |
590 | em_len = em->len; |
591 | em_start = em->start; | |
d20f7043 | 592 | |
c8b97818 | 593 | free_extent_map(em); |
e04ca626 | 594 | em = NULL; |
c8b97818 | 595 | |
81381053 | 596 | cb->len = bio->bi_iter.bi_size; |
c8b97818 | 597 | cb->compressed_len = compressed_len; |
261507a0 | 598 | cb->compress_type = extent_compress_type(bio_flags); |
c8b97818 CM |
599 | cb->orig_bio = bio; |
600 | ||
09cbfeaf | 601 | nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); |
31e818fe | 602 | cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *), |
c8b97818 | 603 | GFP_NOFS); |
6b82ce8d | 604 | if (!cb->compressed_pages) |
605 | goto fail1; | |
606 | ||
0b246afa | 607 | bdev = fs_info->fs_devices->latest_bdev; |
c8b97818 | 608 | |
306e16ce DS |
609 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
610 | cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | | |
c8b97818 | 611 | __GFP_HIGHMEM); |
15e3004a JB |
612 | if (!cb->compressed_pages[pg_index]) { |
613 | faili = pg_index - 1; | |
0e9350de | 614 | ret = BLK_STS_RESOURCE; |
6b82ce8d | 615 | goto fail2; |
15e3004a | 616 | } |
c8b97818 | 617 | } |
15e3004a | 618 | faili = nr_pages - 1; |
c8b97818 CM |
619 | cb->nr_pages = nr_pages; |
620 | ||
7f042a83 | 621 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 622 | |
771ed689 | 623 | /* include any pages we added in add_ra-bio_pages */ |
81381053 | 624 | cb->len = bio->bi_iter.bi_size; |
771ed689 | 625 | |
e749af44 DS |
626 | comp_bio = btrfs_bio_alloc(cur_disk_byte); |
627 | bio_set_dev(comp_bio, bdev); | |
ebcc3263 | 628 | comp_bio->bi_opf = REQ_OP_READ; |
c8b97818 CM |
629 | comp_bio->bi_private = cb; |
630 | comp_bio->bi_end_io = end_compressed_bio_read; | |
a50299ae | 631 | refcount_set(&cb->pending_bios, 1); |
c8b97818 | 632 | |
306e16ce | 633 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
4e4cbee9 CH |
634 | int submit = 0; |
635 | ||
306e16ce | 636 | page = cb->compressed_pages[pg_index]; |
c8b97818 | 637 | page->mapping = inode->i_mapping; |
09cbfeaf | 638 | page->index = em_start >> PAGE_SHIFT; |
d20f7043 | 639 | |
4f024f37 | 640 | if (comp_bio->bi_iter.bi_size) |
da12fe54 NB |
641 | submit = btrfs_bio_fits_in_stripe(page, PAGE_SIZE, |
642 | comp_bio, 0); | |
c8b97818 | 643 | |
70b99e69 | 644 | page->mapping = NULL; |
4e4cbee9 | 645 | if (submit || bio_add_page(comp_bio, page, PAGE_SIZE, 0) < |
09cbfeaf | 646 | PAGE_SIZE) { |
10fe6ca8 JT |
647 | unsigned int nr_sectors; |
648 | ||
0b246afa JM |
649 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, |
650 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 651 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 652 | |
af09abfe CM |
653 | /* |
654 | * inc the count before we submit the bio so | |
655 | * we know the end IO handler won't happen before | |
656 | * we inc the count. Otherwise, the cb might get | |
657 | * freed before we're done setting it up | |
658 | */ | |
a50299ae | 659 | refcount_inc(&cb->pending_bios); |
af09abfe | 660 | |
6cbff00f | 661 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
2ff7e61e | 662 | ret = btrfs_lookup_bio_sums(inode, comp_bio, |
10fe6ca8 | 663 | sums); |
79787eaa | 664 | BUG_ON(ret); /* -ENOMEM */ |
d20f7043 | 665 | } |
10fe6ca8 JT |
666 | |
667 | nr_sectors = DIV_ROUND_UP(comp_bio->bi_iter.bi_size, | |
668 | fs_info->sectorsize); | |
669 | sums += csum_size * nr_sectors; | |
d20f7043 | 670 | |
2ff7e61e | 671 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num, 0); |
4246a0b6 | 672 | if (ret) { |
4e4cbee9 | 673 | comp_bio->bi_status = ret; |
4246a0b6 CH |
674 | bio_endio(comp_bio); |
675 | } | |
c8b97818 | 676 | |
e749af44 DS |
677 | comp_bio = btrfs_bio_alloc(cur_disk_byte); |
678 | bio_set_dev(comp_bio, bdev); | |
ebcc3263 | 679 | comp_bio->bi_opf = REQ_OP_READ; |
771ed689 CM |
680 | comp_bio->bi_private = cb; |
681 | comp_bio->bi_end_io = end_compressed_bio_read; | |
682 | ||
09cbfeaf | 683 | bio_add_page(comp_bio, page, PAGE_SIZE, 0); |
c8b97818 | 684 | } |
09cbfeaf | 685 | cur_disk_byte += PAGE_SIZE; |
c8b97818 | 686 | } |
c8b97818 | 687 | |
0b246afa | 688 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 689 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 690 | |
c2db1073 | 691 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
10fe6ca8 | 692 | ret = btrfs_lookup_bio_sums(inode, comp_bio, sums); |
79787eaa | 693 | BUG_ON(ret); /* -ENOMEM */ |
c2db1073 | 694 | } |
d20f7043 | 695 | |
2ff7e61e | 696 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num, 0); |
4246a0b6 | 697 | if (ret) { |
4e4cbee9 | 698 | comp_bio->bi_status = ret; |
4246a0b6 CH |
699 | bio_endio(comp_bio); |
700 | } | |
c8b97818 | 701 | |
c8b97818 | 702 | return 0; |
6b82ce8d | 703 | |
704 | fail2: | |
15e3004a JB |
705 | while (faili >= 0) { |
706 | __free_page(cb->compressed_pages[faili]); | |
707 | faili--; | |
708 | } | |
6b82ce8d | 709 | |
710 | kfree(cb->compressed_pages); | |
711 | fail1: | |
712 | kfree(cb); | |
713 | out: | |
714 | free_extent_map(em); | |
715 | return ret; | |
c8b97818 | 716 | } |
261507a0 | 717 | |
17b5a6c1 TT |
718 | /* |
719 | * Heuristic uses systematic sampling to collect data from the input data | |
720 | * range, the logic can be tuned by the following constants: | |
721 | * | |
722 | * @SAMPLING_READ_SIZE - how many bytes will be copied from for each sample | |
723 | * @SAMPLING_INTERVAL - range from which the sampled data can be collected | |
724 | */ | |
725 | #define SAMPLING_READ_SIZE (16) | |
726 | #define SAMPLING_INTERVAL (256) | |
727 | ||
728 | /* | |
729 | * For statistical analysis of the input data we consider bytes that form a | |
730 | * Galois Field of 256 objects. Each object has an attribute count, ie. how | |
731 | * many times the object appeared in the sample. | |
732 | */ | |
733 | #define BUCKET_SIZE (256) | |
734 | ||
735 | /* | |
736 | * The size of the sample is based on a statistical sampling rule of thumb. | |
737 | * The common way is to perform sampling tests as long as the number of | |
738 | * elements in each cell is at least 5. | |
739 | * | |
740 | * Instead of 5, we choose 32 to obtain more accurate results. | |
741 | * If the data contain the maximum number of symbols, which is 256, we obtain a | |
742 | * sample size bound by 8192. | |
743 | * | |
744 | * For a sample of at most 8KB of data per data range: 16 consecutive bytes | |
745 | * from up to 512 locations. | |
746 | */ | |
747 | #define MAX_SAMPLE_SIZE (BTRFS_MAX_UNCOMPRESSED * \ | |
748 | SAMPLING_READ_SIZE / SAMPLING_INTERVAL) | |
749 | ||
750 | struct bucket_item { | |
751 | u32 count; | |
752 | }; | |
4e439a0b TT |
753 | |
754 | struct heuristic_ws { | |
17b5a6c1 TT |
755 | /* Partial copy of input data */ |
756 | u8 *sample; | |
a440d48c | 757 | u32 sample_size; |
17b5a6c1 TT |
758 | /* Buckets store counters for each byte value */ |
759 | struct bucket_item *bucket; | |
440c840c TT |
760 | /* Sorting buffer */ |
761 | struct bucket_item *bucket_b; | |
4e439a0b TT |
762 | struct list_head list; |
763 | }; | |
764 | ||
92ee5530 DZ |
765 | static struct workspace_manager heuristic_wsm; |
766 | ||
767 | static void heuristic_init_workspace_manager(void) | |
768 | { | |
769 | btrfs_init_workspace_manager(&heuristic_wsm, &btrfs_heuristic_compress); | |
770 | } | |
771 | ||
772 | static void heuristic_cleanup_workspace_manager(void) | |
773 | { | |
774 | btrfs_cleanup_workspace_manager(&heuristic_wsm); | |
775 | } | |
776 | ||
7bf49943 | 777 | static struct list_head *heuristic_get_workspace(unsigned int level) |
92ee5530 | 778 | { |
7bf49943 | 779 | return btrfs_get_workspace(&heuristic_wsm, level); |
92ee5530 DZ |
780 | } |
781 | ||
782 | static void heuristic_put_workspace(struct list_head *ws) | |
783 | { | |
784 | btrfs_put_workspace(&heuristic_wsm, ws); | |
785 | } | |
786 | ||
4e439a0b TT |
787 | static void free_heuristic_ws(struct list_head *ws) |
788 | { | |
789 | struct heuristic_ws *workspace; | |
790 | ||
791 | workspace = list_entry(ws, struct heuristic_ws, list); | |
792 | ||
17b5a6c1 TT |
793 | kvfree(workspace->sample); |
794 | kfree(workspace->bucket); | |
440c840c | 795 | kfree(workspace->bucket_b); |
4e439a0b TT |
796 | kfree(workspace); |
797 | } | |
798 | ||
7bf49943 | 799 | static struct list_head *alloc_heuristic_ws(unsigned int level) |
4e439a0b TT |
800 | { |
801 | struct heuristic_ws *ws; | |
802 | ||
803 | ws = kzalloc(sizeof(*ws), GFP_KERNEL); | |
804 | if (!ws) | |
805 | return ERR_PTR(-ENOMEM); | |
806 | ||
17b5a6c1 TT |
807 | ws->sample = kvmalloc(MAX_SAMPLE_SIZE, GFP_KERNEL); |
808 | if (!ws->sample) | |
809 | goto fail; | |
810 | ||
811 | ws->bucket = kcalloc(BUCKET_SIZE, sizeof(*ws->bucket), GFP_KERNEL); | |
812 | if (!ws->bucket) | |
813 | goto fail; | |
4e439a0b | 814 | |
440c840c TT |
815 | ws->bucket_b = kcalloc(BUCKET_SIZE, sizeof(*ws->bucket_b), GFP_KERNEL); |
816 | if (!ws->bucket_b) | |
817 | goto fail; | |
818 | ||
17b5a6c1 | 819 | INIT_LIST_HEAD(&ws->list); |
4e439a0b | 820 | return &ws->list; |
17b5a6c1 TT |
821 | fail: |
822 | free_heuristic_ws(&ws->list); | |
823 | return ERR_PTR(-ENOMEM); | |
4e439a0b TT |
824 | } |
825 | ||
ca4ac360 | 826 | const struct btrfs_compress_op btrfs_heuristic_compress = { |
92ee5530 DZ |
827 | .init_workspace_manager = heuristic_init_workspace_manager, |
828 | .cleanup_workspace_manager = heuristic_cleanup_workspace_manager, | |
829 | .get_workspace = heuristic_get_workspace, | |
830 | .put_workspace = heuristic_put_workspace, | |
ca4ac360 DZ |
831 | .alloc_workspace = alloc_heuristic_ws, |
832 | .free_workspace = free_heuristic_ws, | |
833 | }; | |
834 | ||
e8c9f186 | 835 | static const struct btrfs_compress_op * const btrfs_compress_op[] = { |
ca4ac360 DZ |
836 | /* The heuristic is represented as compression type 0 */ |
837 | &btrfs_heuristic_compress, | |
261507a0 | 838 | &btrfs_zlib_compress, |
a6fa6fae | 839 | &btrfs_lzo_compress, |
5c1aab1d | 840 | &btrfs_zstd_compress, |
261507a0 LZ |
841 | }; |
842 | ||
92ee5530 DZ |
843 | void btrfs_init_workspace_manager(struct workspace_manager *wsm, |
844 | const struct btrfs_compress_op *ops) | |
261507a0 | 845 | { |
4e439a0b | 846 | struct list_head *workspace; |
261507a0 | 847 | |
92ee5530 | 848 | wsm->ops = ops; |
10b94a51 | 849 | |
92ee5530 DZ |
850 | INIT_LIST_HEAD(&wsm->idle_ws); |
851 | spin_lock_init(&wsm->ws_lock); | |
852 | atomic_set(&wsm->total_ws, 0); | |
853 | init_waitqueue_head(&wsm->ws_wait); | |
f77dd0d6 | 854 | |
1666edab DZ |
855 | /* |
856 | * Preallocate one workspace for each compression type so we can | |
857 | * guarantee forward progress in the worst case | |
858 | */ | |
7bf49943 | 859 | workspace = wsm->ops->alloc_workspace(0); |
1666edab DZ |
860 | if (IS_ERR(workspace)) { |
861 | pr_warn( | |
862 | "BTRFS: cannot preallocate compression workspace, will try later\n"); | |
863 | } else { | |
92ee5530 DZ |
864 | atomic_set(&wsm->total_ws, 1); |
865 | wsm->free_ws = 1; | |
866 | list_add(workspace, &wsm->idle_ws); | |
1666edab DZ |
867 | } |
868 | } | |
869 | ||
92ee5530 | 870 | void btrfs_cleanup_workspace_manager(struct workspace_manager *wsman) |
1666edab DZ |
871 | { |
872 | struct list_head *ws; | |
873 | ||
874 | while (!list_empty(&wsman->idle_ws)) { | |
875 | ws = wsman->idle_ws.next; | |
876 | list_del(ws); | |
877 | wsman->ops->free_workspace(ws); | |
878 | atomic_dec(&wsman->total_ws); | |
261507a0 | 879 | } |
261507a0 LZ |
880 | } |
881 | ||
882 | /* | |
e721e49d DS |
883 | * This finds an available workspace or allocates a new one. |
884 | * If it's not possible to allocate a new one, waits until there's one. | |
885 | * Preallocation makes a forward progress guarantees and we do not return | |
886 | * errors. | |
261507a0 | 887 | */ |
7bf49943 DZ |
888 | struct list_head *btrfs_get_workspace(struct workspace_manager *wsm, |
889 | unsigned int level) | |
261507a0 LZ |
890 | { |
891 | struct list_head *workspace; | |
892 | int cpus = num_online_cpus(); | |
fe308533 | 893 | unsigned nofs_flag; |
4e439a0b TT |
894 | struct list_head *idle_ws; |
895 | spinlock_t *ws_lock; | |
896 | atomic_t *total_ws; | |
897 | wait_queue_head_t *ws_wait; | |
898 | int *free_ws; | |
899 | ||
92ee5530 DZ |
900 | idle_ws = &wsm->idle_ws; |
901 | ws_lock = &wsm->ws_lock; | |
902 | total_ws = &wsm->total_ws; | |
903 | ws_wait = &wsm->ws_wait; | |
904 | free_ws = &wsm->free_ws; | |
261507a0 | 905 | |
261507a0 | 906 | again: |
d9187649 BL |
907 | spin_lock(ws_lock); |
908 | if (!list_empty(idle_ws)) { | |
909 | workspace = idle_ws->next; | |
261507a0 | 910 | list_del(workspace); |
6ac10a6a | 911 | (*free_ws)--; |
d9187649 | 912 | spin_unlock(ws_lock); |
261507a0 LZ |
913 | return workspace; |
914 | ||
915 | } | |
6ac10a6a | 916 | if (atomic_read(total_ws) > cpus) { |
261507a0 LZ |
917 | DEFINE_WAIT(wait); |
918 | ||
d9187649 BL |
919 | spin_unlock(ws_lock); |
920 | prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE); | |
6ac10a6a | 921 | if (atomic_read(total_ws) > cpus && !*free_ws) |
261507a0 | 922 | schedule(); |
d9187649 | 923 | finish_wait(ws_wait, &wait); |
261507a0 LZ |
924 | goto again; |
925 | } | |
6ac10a6a | 926 | atomic_inc(total_ws); |
d9187649 | 927 | spin_unlock(ws_lock); |
261507a0 | 928 | |
fe308533 DS |
929 | /* |
930 | * Allocation helpers call vmalloc that can't use GFP_NOFS, so we have | |
931 | * to turn it off here because we might get called from the restricted | |
932 | * context of btrfs_compress_bio/btrfs_compress_pages | |
933 | */ | |
934 | nofs_flag = memalloc_nofs_save(); | |
7bf49943 | 935 | workspace = wsm->ops->alloc_workspace(level); |
fe308533 DS |
936 | memalloc_nofs_restore(nofs_flag); |
937 | ||
261507a0 | 938 | if (IS_ERR(workspace)) { |
6ac10a6a | 939 | atomic_dec(total_ws); |
d9187649 | 940 | wake_up(ws_wait); |
e721e49d DS |
941 | |
942 | /* | |
943 | * Do not return the error but go back to waiting. There's a | |
944 | * workspace preallocated for each type and the compression | |
945 | * time is bounded so we get to a workspace eventually. This | |
946 | * makes our caller's life easier. | |
52356716 DS |
947 | * |
948 | * To prevent silent and low-probability deadlocks (when the | |
949 | * initial preallocation fails), check if there are any | |
950 | * workspaces at all. | |
e721e49d | 951 | */ |
52356716 DS |
952 | if (atomic_read(total_ws) == 0) { |
953 | static DEFINE_RATELIMIT_STATE(_rs, | |
954 | /* once per minute */ 60 * HZ, | |
955 | /* no burst */ 1); | |
956 | ||
957 | if (__ratelimit(&_rs)) { | |
ab8d0fc4 | 958 | pr_warn("BTRFS: no compression workspaces, low memory, retrying\n"); |
52356716 DS |
959 | } |
960 | } | |
e721e49d | 961 | goto again; |
261507a0 LZ |
962 | } |
963 | return workspace; | |
964 | } | |
965 | ||
7bf49943 | 966 | static struct list_head *get_workspace(int type, int level) |
929f4baf | 967 | { |
7bf49943 | 968 | return btrfs_compress_op[type]->get_workspace(level); |
929f4baf DZ |
969 | } |
970 | ||
261507a0 LZ |
971 | /* |
972 | * put a workspace struct back on the list or free it if we have enough | |
973 | * idle ones sitting around | |
974 | */ | |
92ee5530 | 975 | void btrfs_put_workspace(struct workspace_manager *wsm, struct list_head *ws) |
261507a0 | 976 | { |
4e439a0b TT |
977 | struct list_head *idle_ws; |
978 | spinlock_t *ws_lock; | |
979 | atomic_t *total_ws; | |
980 | wait_queue_head_t *ws_wait; | |
981 | int *free_ws; | |
982 | ||
92ee5530 DZ |
983 | idle_ws = &wsm->idle_ws; |
984 | ws_lock = &wsm->ws_lock; | |
985 | total_ws = &wsm->total_ws; | |
986 | ws_wait = &wsm->ws_wait; | |
987 | free_ws = &wsm->free_ws; | |
d9187649 BL |
988 | |
989 | spin_lock(ws_lock); | |
26b28dce | 990 | if (*free_ws <= num_online_cpus()) { |
929f4baf | 991 | list_add(ws, idle_ws); |
6ac10a6a | 992 | (*free_ws)++; |
d9187649 | 993 | spin_unlock(ws_lock); |
261507a0 LZ |
994 | goto wake; |
995 | } | |
d9187649 | 996 | spin_unlock(ws_lock); |
261507a0 | 997 | |
92ee5530 | 998 | wsm->ops->free_workspace(ws); |
6ac10a6a | 999 | atomic_dec(total_ws); |
261507a0 | 1000 | wake: |
093258e6 | 1001 | cond_wake_up(ws_wait); |
261507a0 LZ |
1002 | } |
1003 | ||
929f4baf DZ |
1004 | static void put_workspace(int type, struct list_head *ws) |
1005 | { | |
92ee5530 | 1006 | return btrfs_compress_op[type]->put_workspace(ws); |
929f4baf DZ |
1007 | } |
1008 | ||
261507a0 | 1009 | /* |
38c31464 DS |
1010 | * Given an address space and start and length, compress the bytes into @pages |
1011 | * that are allocated on demand. | |
261507a0 | 1012 | * |
f51d2b59 DS |
1013 | * @type_level is encoded algorithm and level, where level 0 means whatever |
1014 | * default the algorithm chooses and is opaque here; | |
1015 | * - compression algo are 0-3 | |
1016 | * - the level are bits 4-7 | |
1017 | * | |
4d3a800e DS |
1018 | * @out_pages is an in/out parameter, holds maximum number of pages to allocate |
1019 | * and returns number of actually allocated pages | |
261507a0 | 1020 | * |
38c31464 DS |
1021 | * @total_in is used to return the number of bytes actually read. It |
1022 | * may be smaller than the input length if we had to exit early because we | |
261507a0 LZ |
1023 | * ran out of room in the pages array or because we cross the |
1024 | * max_out threshold. | |
1025 | * | |
38c31464 DS |
1026 | * @total_out is an in/out parameter, must be set to the input length and will |
1027 | * be also used to return the total number of compressed bytes | |
261507a0 | 1028 | * |
38c31464 | 1029 | * @max_out tells us the max number of bytes that we're allowed to |
261507a0 LZ |
1030 | * stuff into pages |
1031 | */ | |
f51d2b59 | 1032 | int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, |
38c31464 | 1033 | u64 start, struct page **pages, |
261507a0 LZ |
1034 | unsigned long *out_pages, |
1035 | unsigned long *total_in, | |
e5d74902 | 1036 | unsigned long *total_out) |
261507a0 | 1037 | { |
1972708a | 1038 | int type = btrfs_compress_type(type_level); |
7bf49943 | 1039 | int level = btrfs_compress_level(type_level); |
261507a0 LZ |
1040 | struct list_head *workspace; |
1041 | int ret; | |
1042 | ||
b0c1fe1e | 1043 | level = btrfs_compress_set_level(type, level); |
7bf49943 | 1044 | workspace = get_workspace(type, level); |
ca4ac360 | 1045 | ret = btrfs_compress_op[type]->compress_pages(workspace, mapping, |
38c31464 | 1046 | start, pages, |
4d3a800e | 1047 | out_pages, |
e5d74902 | 1048 | total_in, total_out); |
929f4baf | 1049 | put_workspace(type, workspace); |
261507a0 LZ |
1050 | return ret; |
1051 | } | |
1052 | ||
1053 | /* | |
1054 | * pages_in is an array of pages with compressed data. | |
1055 | * | |
1056 | * disk_start is the starting logical offset of this array in the file | |
1057 | * | |
974b1adc | 1058 | * orig_bio contains the pages from the file that we want to decompress into |
261507a0 LZ |
1059 | * |
1060 | * srclen is the number of bytes in pages_in | |
1061 | * | |
1062 | * The basic idea is that we have a bio that was created by readpages. | |
1063 | * The pages in the bio are for the uncompressed data, and they may not | |
1064 | * be contiguous. They all correspond to the range of bytes covered by | |
1065 | * the compressed extent. | |
1066 | */ | |
8140dc30 | 1067 | static int btrfs_decompress_bio(struct compressed_bio *cb) |
261507a0 LZ |
1068 | { |
1069 | struct list_head *workspace; | |
1070 | int ret; | |
8140dc30 | 1071 | int type = cb->compress_type; |
261507a0 | 1072 | |
7bf49943 | 1073 | workspace = get_workspace(type, 0); |
ca4ac360 | 1074 | ret = btrfs_compress_op[type]->decompress_bio(workspace, cb); |
929f4baf | 1075 | put_workspace(type, workspace); |
e1ddce71 | 1076 | |
261507a0 LZ |
1077 | return ret; |
1078 | } | |
1079 | ||
1080 | /* | |
1081 | * a less complex decompression routine. Our compressed data fits in a | |
1082 | * single page, and we want to read a single page out of it. | |
1083 | * start_byte tells us the offset into the compressed data we're interested in | |
1084 | */ | |
1085 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, | |
1086 | unsigned long start_byte, size_t srclen, size_t destlen) | |
1087 | { | |
1088 | struct list_head *workspace; | |
1089 | int ret; | |
1090 | ||
7bf49943 | 1091 | workspace = get_workspace(type, 0); |
ca4ac360 | 1092 | ret = btrfs_compress_op[type]->decompress(workspace, data_in, |
261507a0 LZ |
1093 | dest_page, start_byte, |
1094 | srclen, destlen); | |
929f4baf | 1095 | put_workspace(type, workspace); |
7bf49943 | 1096 | |
261507a0 LZ |
1097 | return ret; |
1098 | } | |
1099 | ||
1666edab DZ |
1100 | void __init btrfs_init_compress(void) |
1101 | { | |
1102 | int i; | |
1103 | ||
1104 | for (i = 0; i < BTRFS_NR_WORKSPACE_MANAGERS; i++) | |
92ee5530 | 1105 | btrfs_compress_op[i]->init_workspace_manager(); |
1666edab DZ |
1106 | } |
1107 | ||
e67c718b | 1108 | void __cold btrfs_exit_compress(void) |
261507a0 | 1109 | { |
1666edab DZ |
1110 | int i; |
1111 | ||
1112 | for (i = 0; i < BTRFS_NR_WORKSPACE_MANAGERS; i++) | |
92ee5530 | 1113 | btrfs_compress_op[i]->cleanup_workspace_manager(); |
261507a0 | 1114 | } |
3a39c18d LZ |
1115 | |
1116 | /* | |
1117 | * Copy uncompressed data from working buffer to pages. | |
1118 | * | |
1119 | * buf_start is the byte offset we're of the start of our workspace buffer. | |
1120 | * | |
1121 | * total_out is the last byte of the buffer | |
1122 | */ | |
14a3357b | 1123 | int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, |
3a39c18d | 1124 | unsigned long total_out, u64 disk_start, |
974b1adc | 1125 | struct bio *bio) |
3a39c18d LZ |
1126 | { |
1127 | unsigned long buf_offset; | |
1128 | unsigned long current_buf_start; | |
1129 | unsigned long start_byte; | |
6e78b3f7 | 1130 | unsigned long prev_start_byte; |
3a39c18d LZ |
1131 | unsigned long working_bytes = total_out - buf_start; |
1132 | unsigned long bytes; | |
1133 | char *kaddr; | |
974b1adc | 1134 | struct bio_vec bvec = bio_iter_iovec(bio, bio->bi_iter); |
3a39c18d LZ |
1135 | |
1136 | /* | |
1137 | * start byte is the first byte of the page we're currently | |
1138 | * copying into relative to the start of the compressed data. | |
1139 | */ | |
974b1adc | 1140 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d LZ |
1141 | |
1142 | /* we haven't yet hit data corresponding to this page */ | |
1143 | if (total_out <= start_byte) | |
1144 | return 1; | |
1145 | ||
1146 | /* | |
1147 | * the start of the data we care about is offset into | |
1148 | * the middle of our working buffer | |
1149 | */ | |
1150 | if (total_out > start_byte && buf_start < start_byte) { | |
1151 | buf_offset = start_byte - buf_start; | |
1152 | working_bytes -= buf_offset; | |
1153 | } else { | |
1154 | buf_offset = 0; | |
1155 | } | |
1156 | current_buf_start = buf_start; | |
1157 | ||
1158 | /* copy bytes from the working buffer into the pages */ | |
1159 | while (working_bytes > 0) { | |
974b1adc CH |
1160 | bytes = min_t(unsigned long, bvec.bv_len, |
1161 | PAGE_SIZE - buf_offset); | |
3a39c18d | 1162 | bytes = min(bytes, working_bytes); |
974b1adc CH |
1163 | |
1164 | kaddr = kmap_atomic(bvec.bv_page); | |
1165 | memcpy(kaddr + bvec.bv_offset, buf + buf_offset, bytes); | |
7ac687d9 | 1166 | kunmap_atomic(kaddr); |
974b1adc | 1167 | flush_dcache_page(bvec.bv_page); |
3a39c18d | 1168 | |
3a39c18d LZ |
1169 | buf_offset += bytes; |
1170 | working_bytes -= bytes; | |
1171 | current_buf_start += bytes; | |
1172 | ||
1173 | /* check if we need to pick another page */ | |
974b1adc CH |
1174 | bio_advance(bio, bytes); |
1175 | if (!bio->bi_iter.bi_size) | |
1176 | return 0; | |
1177 | bvec = bio_iter_iovec(bio, bio->bi_iter); | |
6e78b3f7 | 1178 | prev_start_byte = start_byte; |
974b1adc | 1179 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d | 1180 | |
974b1adc | 1181 | /* |
6e78b3f7 OS |
1182 | * We need to make sure we're only adjusting |
1183 | * our offset into compression working buffer when | |
1184 | * we're switching pages. Otherwise we can incorrectly | |
1185 | * keep copying when we were actually done. | |
974b1adc | 1186 | */ |
6e78b3f7 OS |
1187 | if (start_byte != prev_start_byte) { |
1188 | /* | |
1189 | * make sure our new page is covered by this | |
1190 | * working buffer | |
1191 | */ | |
1192 | if (total_out <= start_byte) | |
1193 | return 1; | |
3a39c18d | 1194 | |
6e78b3f7 OS |
1195 | /* |
1196 | * the next page in the biovec might not be adjacent | |
1197 | * to the last page, but it might still be found | |
1198 | * inside this working buffer. bump our offset pointer | |
1199 | */ | |
1200 | if (total_out > start_byte && | |
1201 | current_buf_start < start_byte) { | |
1202 | buf_offset = start_byte - buf_start; | |
1203 | working_bytes = total_out - start_byte; | |
1204 | current_buf_start = buf_start + buf_offset; | |
1205 | } | |
3a39c18d LZ |
1206 | } |
1207 | } | |
1208 | ||
1209 | return 1; | |
1210 | } | |
c2fcdcdf | 1211 | |
19562430 TT |
1212 | /* |
1213 | * Shannon Entropy calculation | |
1214 | * | |
52042d8e | 1215 | * Pure byte distribution analysis fails to determine compressibility of data. |
19562430 TT |
1216 | * Try calculating entropy to estimate the average minimum number of bits |
1217 | * needed to encode the sampled data. | |
1218 | * | |
1219 | * For convenience, return the percentage of needed bits, instead of amount of | |
1220 | * bits directly. | |
1221 | * | |
1222 | * @ENTROPY_LVL_ACEPTABLE - below that threshold, sample has low byte entropy | |
1223 | * and can be compressible with high probability | |
1224 | * | |
1225 | * @ENTROPY_LVL_HIGH - data are not compressible with high probability | |
1226 | * | |
1227 | * Use of ilog2() decreases precision, we lower the LVL to 5 to compensate. | |
1228 | */ | |
1229 | #define ENTROPY_LVL_ACEPTABLE (65) | |
1230 | #define ENTROPY_LVL_HIGH (80) | |
1231 | ||
1232 | /* | |
1233 | * For increasead precision in shannon_entropy calculation, | |
1234 | * let's do pow(n, M) to save more digits after comma: | |
1235 | * | |
1236 | * - maximum int bit length is 64 | |
1237 | * - ilog2(MAX_SAMPLE_SIZE) -> 13 | |
1238 | * - 13 * 4 = 52 < 64 -> M = 4 | |
1239 | * | |
1240 | * So use pow(n, 4). | |
1241 | */ | |
1242 | static inline u32 ilog2_w(u64 n) | |
1243 | { | |
1244 | return ilog2(n * n * n * n); | |
1245 | } | |
1246 | ||
1247 | static u32 shannon_entropy(struct heuristic_ws *ws) | |
1248 | { | |
1249 | const u32 entropy_max = 8 * ilog2_w(2); | |
1250 | u32 entropy_sum = 0; | |
1251 | u32 p, p_base, sz_base; | |
1252 | u32 i; | |
1253 | ||
1254 | sz_base = ilog2_w(ws->sample_size); | |
1255 | for (i = 0; i < BUCKET_SIZE && ws->bucket[i].count > 0; i++) { | |
1256 | p = ws->bucket[i].count; | |
1257 | p_base = ilog2_w(p); | |
1258 | entropy_sum += p * (sz_base - p_base); | |
1259 | } | |
1260 | ||
1261 | entropy_sum /= ws->sample_size; | |
1262 | return entropy_sum * 100 / entropy_max; | |
1263 | } | |
1264 | ||
440c840c TT |
1265 | #define RADIX_BASE 4U |
1266 | #define COUNTERS_SIZE (1U << RADIX_BASE) | |
1267 | ||
1268 | static u8 get4bits(u64 num, int shift) { | |
1269 | u8 low4bits; | |
1270 | ||
1271 | num >>= shift; | |
1272 | /* Reverse order */ | |
1273 | low4bits = (COUNTERS_SIZE - 1) - (num % COUNTERS_SIZE); | |
1274 | return low4bits; | |
1275 | } | |
1276 | ||
440c840c TT |
1277 | /* |
1278 | * Use 4 bits as radix base | |
52042d8e | 1279 | * Use 16 u32 counters for calculating new position in buf array |
440c840c TT |
1280 | * |
1281 | * @array - array that will be sorted | |
1282 | * @array_buf - buffer array to store sorting results | |
1283 | * must be equal in size to @array | |
1284 | * @num - array size | |
440c840c | 1285 | */ |
23ae8c63 | 1286 | static void radix_sort(struct bucket_item *array, struct bucket_item *array_buf, |
36243c91 | 1287 | int num) |
858177d3 | 1288 | { |
440c840c TT |
1289 | u64 max_num; |
1290 | u64 buf_num; | |
1291 | u32 counters[COUNTERS_SIZE]; | |
1292 | u32 new_addr; | |
1293 | u32 addr; | |
1294 | int bitlen; | |
1295 | int shift; | |
1296 | int i; | |
858177d3 | 1297 | |
440c840c TT |
1298 | /* |
1299 | * Try avoid useless loop iterations for small numbers stored in big | |
1300 | * counters. Example: 48 33 4 ... in 64bit array | |
1301 | */ | |
23ae8c63 | 1302 | max_num = array[0].count; |
440c840c | 1303 | for (i = 1; i < num; i++) { |
23ae8c63 | 1304 | buf_num = array[i].count; |
440c840c TT |
1305 | if (buf_num > max_num) |
1306 | max_num = buf_num; | |
1307 | } | |
1308 | ||
1309 | buf_num = ilog2(max_num); | |
1310 | bitlen = ALIGN(buf_num, RADIX_BASE * 2); | |
1311 | ||
1312 | shift = 0; | |
1313 | while (shift < bitlen) { | |
1314 | memset(counters, 0, sizeof(counters)); | |
1315 | ||
1316 | for (i = 0; i < num; i++) { | |
23ae8c63 | 1317 | buf_num = array[i].count; |
440c840c TT |
1318 | addr = get4bits(buf_num, shift); |
1319 | counters[addr]++; | |
1320 | } | |
1321 | ||
1322 | for (i = 1; i < COUNTERS_SIZE; i++) | |
1323 | counters[i] += counters[i - 1]; | |
1324 | ||
1325 | for (i = num - 1; i >= 0; i--) { | |
23ae8c63 | 1326 | buf_num = array[i].count; |
440c840c TT |
1327 | addr = get4bits(buf_num, shift); |
1328 | counters[addr]--; | |
1329 | new_addr = counters[addr]; | |
7add17be | 1330 | array_buf[new_addr] = array[i]; |
440c840c TT |
1331 | } |
1332 | ||
1333 | shift += RADIX_BASE; | |
1334 | ||
1335 | /* | |
1336 | * Normal radix expects to move data from a temporary array, to | |
1337 | * the main one. But that requires some CPU time. Avoid that | |
1338 | * by doing another sort iteration to original array instead of | |
1339 | * memcpy() | |
1340 | */ | |
1341 | memset(counters, 0, sizeof(counters)); | |
1342 | ||
1343 | for (i = 0; i < num; i ++) { | |
23ae8c63 | 1344 | buf_num = array_buf[i].count; |
440c840c TT |
1345 | addr = get4bits(buf_num, shift); |
1346 | counters[addr]++; | |
1347 | } | |
1348 | ||
1349 | for (i = 1; i < COUNTERS_SIZE; i++) | |
1350 | counters[i] += counters[i - 1]; | |
1351 | ||
1352 | for (i = num - 1; i >= 0; i--) { | |
23ae8c63 | 1353 | buf_num = array_buf[i].count; |
440c840c TT |
1354 | addr = get4bits(buf_num, shift); |
1355 | counters[addr]--; | |
1356 | new_addr = counters[addr]; | |
7add17be | 1357 | array[new_addr] = array_buf[i]; |
440c840c TT |
1358 | } |
1359 | ||
1360 | shift += RADIX_BASE; | |
1361 | } | |
858177d3 TT |
1362 | } |
1363 | ||
1364 | /* | |
1365 | * Size of the core byte set - how many bytes cover 90% of the sample | |
1366 | * | |
1367 | * There are several types of structured binary data that use nearly all byte | |
1368 | * values. The distribution can be uniform and counts in all buckets will be | |
1369 | * nearly the same (eg. encrypted data). Unlikely to be compressible. | |
1370 | * | |
1371 | * Other possibility is normal (Gaussian) distribution, where the data could | |
1372 | * be potentially compressible, but we have to take a few more steps to decide | |
1373 | * how much. | |
1374 | * | |
1375 | * @BYTE_CORE_SET_LOW - main part of byte values repeated frequently, | |
1376 | * compression algo can easy fix that | |
1377 | * @BYTE_CORE_SET_HIGH - data have uniform distribution and with high | |
1378 | * probability is not compressible | |
1379 | */ | |
1380 | #define BYTE_CORE_SET_LOW (64) | |
1381 | #define BYTE_CORE_SET_HIGH (200) | |
1382 | ||
1383 | static int byte_core_set_size(struct heuristic_ws *ws) | |
1384 | { | |
1385 | u32 i; | |
1386 | u32 coreset_sum = 0; | |
1387 | const u32 core_set_threshold = ws->sample_size * 90 / 100; | |
1388 | struct bucket_item *bucket = ws->bucket; | |
1389 | ||
1390 | /* Sort in reverse order */ | |
36243c91 | 1391 | radix_sort(ws->bucket, ws->bucket_b, BUCKET_SIZE); |
858177d3 TT |
1392 | |
1393 | for (i = 0; i < BYTE_CORE_SET_LOW; i++) | |
1394 | coreset_sum += bucket[i].count; | |
1395 | ||
1396 | if (coreset_sum > core_set_threshold) | |
1397 | return i; | |
1398 | ||
1399 | for (; i < BYTE_CORE_SET_HIGH && bucket[i].count > 0; i++) { | |
1400 | coreset_sum += bucket[i].count; | |
1401 | if (coreset_sum > core_set_threshold) | |
1402 | break; | |
1403 | } | |
1404 | ||
1405 | return i; | |
1406 | } | |
1407 | ||
a288e92c TT |
1408 | /* |
1409 | * Count byte values in buckets. | |
1410 | * This heuristic can detect textual data (configs, xml, json, html, etc). | |
1411 | * Because in most text-like data byte set is restricted to limited number of | |
1412 | * possible characters, and that restriction in most cases makes data easy to | |
1413 | * compress. | |
1414 | * | |
1415 | * @BYTE_SET_THRESHOLD - consider all data within this byte set size: | |
1416 | * less - compressible | |
1417 | * more - need additional analysis | |
1418 | */ | |
1419 | #define BYTE_SET_THRESHOLD (64) | |
1420 | ||
1421 | static u32 byte_set_size(const struct heuristic_ws *ws) | |
1422 | { | |
1423 | u32 i; | |
1424 | u32 byte_set_size = 0; | |
1425 | ||
1426 | for (i = 0; i < BYTE_SET_THRESHOLD; i++) { | |
1427 | if (ws->bucket[i].count > 0) | |
1428 | byte_set_size++; | |
1429 | } | |
1430 | ||
1431 | /* | |
1432 | * Continue collecting count of byte values in buckets. If the byte | |
1433 | * set size is bigger then the threshold, it's pointless to continue, | |
1434 | * the detection technique would fail for this type of data. | |
1435 | */ | |
1436 | for (; i < BUCKET_SIZE; i++) { | |
1437 | if (ws->bucket[i].count > 0) { | |
1438 | byte_set_size++; | |
1439 | if (byte_set_size > BYTE_SET_THRESHOLD) | |
1440 | return byte_set_size; | |
1441 | } | |
1442 | } | |
1443 | ||
1444 | return byte_set_size; | |
1445 | } | |
1446 | ||
1fe4f6fa TT |
1447 | static bool sample_repeated_patterns(struct heuristic_ws *ws) |
1448 | { | |
1449 | const u32 half_of_sample = ws->sample_size / 2; | |
1450 | const u8 *data = ws->sample; | |
1451 | ||
1452 | return memcmp(&data[0], &data[half_of_sample], half_of_sample) == 0; | |
1453 | } | |
1454 | ||
a440d48c TT |
1455 | static void heuristic_collect_sample(struct inode *inode, u64 start, u64 end, |
1456 | struct heuristic_ws *ws) | |
1457 | { | |
1458 | struct page *page; | |
1459 | u64 index, index_end; | |
1460 | u32 i, curr_sample_pos; | |
1461 | u8 *in_data; | |
1462 | ||
1463 | /* | |
1464 | * Compression handles the input data by chunks of 128KiB | |
1465 | * (defined by BTRFS_MAX_UNCOMPRESSED) | |
1466 | * | |
1467 | * We do the same for the heuristic and loop over the whole range. | |
1468 | * | |
1469 | * MAX_SAMPLE_SIZE - calculated under assumption that heuristic will | |
1470 | * process no more than BTRFS_MAX_UNCOMPRESSED at a time. | |
1471 | */ | |
1472 | if (end - start > BTRFS_MAX_UNCOMPRESSED) | |
1473 | end = start + BTRFS_MAX_UNCOMPRESSED; | |
1474 | ||
1475 | index = start >> PAGE_SHIFT; | |
1476 | index_end = end >> PAGE_SHIFT; | |
1477 | ||
1478 | /* Don't miss unaligned end */ | |
1479 | if (!IS_ALIGNED(end, PAGE_SIZE)) | |
1480 | index_end++; | |
1481 | ||
1482 | curr_sample_pos = 0; | |
1483 | while (index < index_end) { | |
1484 | page = find_get_page(inode->i_mapping, index); | |
1485 | in_data = kmap(page); | |
1486 | /* Handle case where the start is not aligned to PAGE_SIZE */ | |
1487 | i = start % PAGE_SIZE; | |
1488 | while (i < PAGE_SIZE - SAMPLING_READ_SIZE) { | |
1489 | /* Don't sample any garbage from the last page */ | |
1490 | if (start > end - SAMPLING_READ_SIZE) | |
1491 | break; | |
1492 | memcpy(&ws->sample[curr_sample_pos], &in_data[i], | |
1493 | SAMPLING_READ_SIZE); | |
1494 | i += SAMPLING_INTERVAL; | |
1495 | start += SAMPLING_INTERVAL; | |
1496 | curr_sample_pos += SAMPLING_READ_SIZE; | |
1497 | } | |
1498 | kunmap(page); | |
1499 | put_page(page); | |
1500 | ||
1501 | index++; | |
1502 | } | |
1503 | ||
1504 | ws->sample_size = curr_sample_pos; | |
1505 | } | |
1506 | ||
c2fcdcdf TT |
1507 | /* |
1508 | * Compression heuristic. | |
1509 | * | |
1510 | * For now is's a naive and optimistic 'return true', we'll extend the logic to | |
1511 | * quickly (compared to direct compression) detect data characteristics | |
1512 | * (compressible/uncompressible) to avoid wasting CPU time on uncompressible | |
1513 | * data. | |
1514 | * | |
1515 | * The following types of analysis can be performed: | |
1516 | * - detect mostly zero data | |
1517 | * - detect data with low "byte set" size (text, etc) | |
1518 | * - detect data with low/high "core byte" set | |
1519 | * | |
1520 | * Return non-zero if the compression should be done, 0 otherwise. | |
1521 | */ | |
1522 | int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) | |
1523 | { | |
7bf49943 | 1524 | struct list_head *ws_list = get_workspace(0, 0); |
4e439a0b | 1525 | struct heuristic_ws *ws; |
a440d48c TT |
1526 | u32 i; |
1527 | u8 byte; | |
19562430 | 1528 | int ret = 0; |
c2fcdcdf | 1529 | |
4e439a0b TT |
1530 | ws = list_entry(ws_list, struct heuristic_ws, list); |
1531 | ||
a440d48c TT |
1532 | heuristic_collect_sample(inode, start, end, ws); |
1533 | ||
1fe4f6fa TT |
1534 | if (sample_repeated_patterns(ws)) { |
1535 | ret = 1; | |
1536 | goto out; | |
1537 | } | |
1538 | ||
a440d48c TT |
1539 | memset(ws->bucket, 0, sizeof(*ws->bucket)*BUCKET_SIZE); |
1540 | ||
1541 | for (i = 0; i < ws->sample_size; i++) { | |
1542 | byte = ws->sample[i]; | |
1543 | ws->bucket[byte].count++; | |
c2fcdcdf TT |
1544 | } |
1545 | ||
a288e92c TT |
1546 | i = byte_set_size(ws); |
1547 | if (i < BYTE_SET_THRESHOLD) { | |
1548 | ret = 2; | |
1549 | goto out; | |
1550 | } | |
1551 | ||
858177d3 TT |
1552 | i = byte_core_set_size(ws); |
1553 | if (i <= BYTE_CORE_SET_LOW) { | |
1554 | ret = 3; | |
1555 | goto out; | |
1556 | } | |
1557 | ||
1558 | if (i >= BYTE_CORE_SET_HIGH) { | |
1559 | ret = 0; | |
1560 | goto out; | |
1561 | } | |
1562 | ||
19562430 TT |
1563 | i = shannon_entropy(ws); |
1564 | if (i <= ENTROPY_LVL_ACEPTABLE) { | |
1565 | ret = 4; | |
1566 | goto out; | |
1567 | } | |
1568 | ||
1569 | /* | |
1570 | * For the levels below ENTROPY_LVL_HIGH, additional analysis would be | |
1571 | * needed to give green light to compression. | |
1572 | * | |
1573 | * For now just assume that compression at that level is not worth the | |
1574 | * resources because: | |
1575 | * | |
1576 | * 1. it is possible to defrag the data later | |
1577 | * | |
1578 | * 2. the data would turn out to be hardly compressible, eg. 150 byte | |
1579 | * values, every bucket has counter at level ~54. The heuristic would | |
1580 | * be confused. This can happen when data have some internal repeated | |
1581 | * patterns like "abbacbbc...". This can be detected by analyzing | |
1582 | * pairs of bytes, which is too costly. | |
1583 | */ | |
1584 | if (i < ENTROPY_LVL_HIGH) { | |
1585 | ret = 5; | |
1586 | goto out; | |
1587 | } else { | |
1588 | ret = 0; | |
1589 | goto out; | |
1590 | } | |
1591 | ||
1fe4f6fa | 1592 | out: |
929f4baf | 1593 | put_workspace(0, ws_list); |
c2fcdcdf TT |
1594 | return ret; |
1595 | } | |
f51d2b59 | 1596 | |
d0ab62ce DZ |
1597 | /* |
1598 | * Convert the compression suffix (eg. after "zlib" starting with ":") to | |
1599 | * level, unrecognized string will set the default level | |
1600 | */ | |
1601 | unsigned int btrfs_compress_str2level(unsigned int type, const char *str) | |
f51d2b59 | 1602 | { |
d0ab62ce DZ |
1603 | unsigned int level = 0; |
1604 | int ret; | |
1605 | ||
1606 | if (!type) | |
f51d2b59 DS |
1607 | return 0; |
1608 | ||
d0ab62ce DZ |
1609 | if (str[0] == ':') { |
1610 | ret = kstrtouint(str + 1, 10, &level); | |
1611 | if (ret) | |
1612 | level = 0; | |
1613 | } | |
1614 | ||
b0c1fe1e DS |
1615 | level = btrfs_compress_set_level(type, level); |
1616 | ||
1617 | return level; | |
1618 | } | |
1619 | ||
1620 | /* | |
1621 | * Adjust @level according to the limits of the compression algorithm or | |
1622 | * fallback to default | |
1623 | */ | |
1624 | unsigned int btrfs_compress_set_level(int type, unsigned level) | |
1625 | { | |
1626 | const struct btrfs_compress_op *ops = btrfs_compress_op[type]; | |
1627 | ||
1628 | if (level == 0) | |
1629 | level = ops->default_level; | |
1630 | else | |
1631 | level = min(level, ops->max_level); | |
f51d2b59 | 1632 | |
d0ab62ce | 1633 | return level; |
f51d2b59 | 1634 | } |