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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 | ||
c4bf665a DS |
32 | int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, |
33 | u64 start, struct page **pages, unsigned long *out_pages, | |
34 | unsigned long *total_in, unsigned long *total_out); | |
35 | int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb); | |
36 | int zlib_decompress(struct list_head *ws, unsigned char *data_in, | |
37 | struct page *dest_page, unsigned long start_byte, size_t srclen, | |
38 | size_t destlen); | |
d20f395f DS |
39 | struct list_head *zlib_alloc_workspace(unsigned int level); |
40 | void zlib_free_workspace(struct list_head *ws); | |
41 | struct list_head *zlib_get_workspace(unsigned int level); | |
c4bf665a DS |
42 | |
43 | int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, | |
44 | u64 start, struct page **pages, unsigned long *out_pages, | |
45 | unsigned long *total_in, unsigned long *total_out); | |
46 | int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb); | |
47 | int lzo_decompress(struct list_head *ws, unsigned char *data_in, | |
48 | struct page *dest_page, unsigned long start_byte, size_t srclen, | |
49 | size_t destlen); | |
d20f395f DS |
50 | struct list_head *lzo_alloc_workspace(unsigned int level); |
51 | void lzo_free_workspace(struct list_head *ws); | |
c4bf665a DS |
52 | |
53 | int zstd_compress_pages(struct list_head *ws, struct address_space *mapping, | |
54 | u64 start, struct page **pages, unsigned long *out_pages, | |
55 | unsigned long *total_in, unsigned long *total_out); | |
56 | int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb); | |
57 | int zstd_decompress(struct list_head *ws, unsigned char *data_in, | |
58 | struct page *dest_page, unsigned long start_byte, size_t srclen, | |
59 | size_t destlen); | |
d5517033 | 60 | void zstd_init_workspace_manager(void); |
2510307e | 61 | void zstd_cleanup_workspace_manager(void); |
d20f395f DS |
62 | struct list_head *zstd_alloc_workspace(unsigned int level); |
63 | void zstd_free_workspace(struct list_head *ws); | |
64 | struct list_head *zstd_get_workspace(unsigned int level); | |
65 | void zstd_put_workspace(struct list_head *ws); | |
c4bf665a | 66 | |
e128f9c3 DS |
67 | static const char* const btrfs_compress_types[] = { "", "zlib", "lzo", "zstd" }; |
68 | ||
69 | const char* btrfs_compress_type2str(enum btrfs_compression_type type) | |
70 | { | |
71 | switch (type) { | |
72 | case BTRFS_COMPRESS_ZLIB: | |
73 | case BTRFS_COMPRESS_LZO: | |
74 | case BTRFS_COMPRESS_ZSTD: | |
75 | case BTRFS_COMPRESS_NONE: | |
76 | return btrfs_compress_types[type]; | |
ce96b7ff CX |
77 | default: |
78 | break; | |
e128f9c3 DS |
79 | } |
80 | ||
81 | return NULL; | |
82 | } | |
83 | ||
aa53e3bf JT |
84 | bool btrfs_compress_is_valid_type(const char *str, size_t len) |
85 | { | |
86 | int i; | |
87 | ||
88 | for (i = 1; i < ARRAY_SIZE(btrfs_compress_types); i++) { | |
89 | size_t comp_len = strlen(btrfs_compress_types[i]); | |
90 | ||
91 | if (len < comp_len) | |
92 | continue; | |
93 | ||
94 | if (!strncmp(btrfs_compress_types[i], str, comp_len)) | |
95 | return true; | |
96 | } | |
97 | return false; | |
98 | } | |
99 | ||
1e4eb746 DS |
100 | static int compression_compress_pages(int type, struct list_head *ws, |
101 | struct address_space *mapping, u64 start, struct page **pages, | |
102 | unsigned long *out_pages, unsigned long *total_in, | |
103 | unsigned long *total_out) | |
104 | { | |
105 | switch (type) { | |
106 | case BTRFS_COMPRESS_ZLIB: | |
107 | return zlib_compress_pages(ws, mapping, start, pages, | |
108 | out_pages, total_in, total_out); | |
109 | case BTRFS_COMPRESS_LZO: | |
110 | return lzo_compress_pages(ws, mapping, start, pages, | |
111 | out_pages, total_in, total_out); | |
112 | case BTRFS_COMPRESS_ZSTD: | |
113 | return zstd_compress_pages(ws, mapping, start, pages, | |
114 | out_pages, total_in, total_out); | |
115 | case BTRFS_COMPRESS_NONE: | |
116 | default: | |
117 | /* | |
118 | * This can't happen, the type is validated several times | |
119 | * before we get here. As a sane fallback, return what the | |
120 | * callers will understand as 'no compression happened'. | |
121 | */ | |
122 | return -E2BIG; | |
123 | } | |
124 | } | |
125 | ||
126 | static int compression_decompress_bio(int type, struct list_head *ws, | |
127 | struct compressed_bio *cb) | |
128 | { | |
129 | switch (type) { | |
130 | case BTRFS_COMPRESS_ZLIB: return zlib_decompress_bio(ws, cb); | |
131 | case BTRFS_COMPRESS_LZO: return lzo_decompress_bio(ws, cb); | |
132 | case BTRFS_COMPRESS_ZSTD: return zstd_decompress_bio(ws, cb); | |
133 | case BTRFS_COMPRESS_NONE: | |
134 | default: | |
135 | /* | |
136 | * This can't happen, the type is validated several times | |
137 | * before we get here. | |
138 | */ | |
139 | BUG(); | |
140 | } | |
141 | } | |
142 | ||
143 | static int compression_decompress(int type, struct list_head *ws, | |
144 | unsigned char *data_in, struct page *dest_page, | |
145 | unsigned long start_byte, size_t srclen, size_t destlen) | |
146 | { | |
147 | switch (type) { | |
148 | case BTRFS_COMPRESS_ZLIB: return zlib_decompress(ws, data_in, dest_page, | |
149 | start_byte, srclen, destlen); | |
150 | case BTRFS_COMPRESS_LZO: return lzo_decompress(ws, data_in, dest_page, | |
151 | start_byte, srclen, destlen); | |
152 | case BTRFS_COMPRESS_ZSTD: return zstd_decompress(ws, data_in, dest_page, | |
153 | start_byte, srclen, destlen); | |
154 | case BTRFS_COMPRESS_NONE: | |
155 | default: | |
156 | /* | |
157 | * This can't happen, the type is validated several times | |
158 | * before we get here. | |
159 | */ | |
160 | BUG(); | |
161 | } | |
162 | } | |
163 | ||
8140dc30 | 164 | static int btrfs_decompress_bio(struct compressed_bio *cb); |
48a3b636 | 165 | |
2ff7e61e | 166 | static inline int compressed_bio_size(struct btrfs_fs_info *fs_info, |
d20f7043 CM |
167 | unsigned long disk_size) |
168 | { | |
0b246afa | 169 | u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
6c41761f | 170 | |
d20f7043 | 171 | return sizeof(struct compressed_bio) + |
0b246afa | 172 | (DIV_ROUND_UP(disk_size, fs_info->sectorsize)) * csum_size; |
d20f7043 CM |
173 | } |
174 | ||
5a9472fe | 175 | static int check_compressed_csum(struct btrfs_inode *inode, struct bio *bio, |
d20f7043 CM |
176 | u64 disk_start) |
177 | { | |
10fe6ca8 | 178 | struct btrfs_fs_info *fs_info = inode->root->fs_info; |
d5178578 | 179 | SHASH_DESC_ON_STACK(shash, fs_info->csum_shash); |
10fe6ca8 | 180 | const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
d20f7043 CM |
181 | struct page *page; |
182 | unsigned long i; | |
183 | char *kaddr; | |
d5178578 | 184 | u8 csum[BTRFS_CSUM_SIZE]; |
5a9472fe | 185 | struct compressed_bio *cb = bio->bi_private; |
10fe6ca8 | 186 | u8 *cb_sum = cb->sums; |
d20f7043 | 187 | |
f898ac6a | 188 | if (inode->flags & BTRFS_INODE_NODATASUM) |
d20f7043 CM |
189 | return 0; |
190 | ||
d5178578 JT |
191 | shash->tfm = fs_info->csum_shash; |
192 | ||
d20f7043 CM |
193 | for (i = 0; i < cb->nr_pages; i++) { |
194 | page = cb->compressed_pages[i]; | |
d20f7043 | 195 | |
7ac687d9 | 196 | kaddr = kmap_atomic(page); |
fd08001f | 197 | crypto_shash_digest(shash, kaddr, PAGE_SIZE, csum); |
7ac687d9 | 198 | kunmap_atomic(kaddr); |
d20f7043 | 199 | |
10fe6ca8 | 200 | if (memcmp(&csum, cb_sum, csum_size)) { |
d5178578 | 201 | btrfs_print_data_csum_error(inode, disk_start, |
ea41d6b2 | 202 | csum, cb_sum, cb->mirror_num); |
5a9472fe NB |
203 | if (btrfs_io_bio(bio)->device) |
204 | btrfs_dev_stat_inc_and_print( | |
205 | btrfs_io_bio(bio)->device, | |
206 | BTRFS_DEV_STAT_CORRUPTION_ERRS); | |
93c4c033 | 207 | return -EIO; |
d20f7043 | 208 | } |
10fe6ca8 | 209 | cb_sum += csum_size; |
d20f7043 | 210 | } |
93c4c033 | 211 | return 0; |
d20f7043 CM |
212 | } |
213 | ||
c8b97818 CM |
214 | /* when we finish reading compressed pages from the disk, we |
215 | * decompress them and then run the bio end_io routines on the | |
216 | * decompressed pages (in the inode address space). | |
217 | * | |
218 | * This allows the checksumming and other IO error handling routines | |
219 | * to work normally | |
220 | * | |
221 | * The compressed pages are freed here, and it must be run | |
222 | * in process context | |
223 | */ | |
4246a0b6 | 224 | static void end_compressed_bio_read(struct bio *bio) |
c8b97818 | 225 | { |
c8b97818 CM |
226 | struct compressed_bio *cb = bio->bi_private; |
227 | struct inode *inode; | |
228 | struct page *page; | |
229 | unsigned long index; | |
cf1167d5 | 230 | unsigned int mirror = btrfs_io_bio(bio)->mirror_num; |
e6311f24 | 231 | int ret = 0; |
c8b97818 | 232 | |
4e4cbee9 | 233 | if (bio->bi_status) |
c8b97818 CM |
234 | cb->errors = 1; |
235 | ||
236 | /* if there are more bios still pending for this compressed | |
237 | * extent, just exit | |
238 | */ | |
a50299ae | 239 | if (!refcount_dec_and_test(&cb->pending_bios)) |
c8b97818 CM |
240 | goto out; |
241 | ||
cf1167d5 LB |
242 | /* |
243 | * Record the correct mirror_num in cb->orig_bio so that | |
244 | * read-repair can work properly. | |
245 | */ | |
cf1167d5 LB |
246 | btrfs_io_bio(cb->orig_bio)->mirror_num = mirror; |
247 | cb->mirror_num = mirror; | |
248 | ||
e6311f24 LB |
249 | /* |
250 | * Some IO in this cb have failed, just skip checksum as there | |
251 | * is no way it could be correct. | |
252 | */ | |
253 | if (cb->errors == 1) | |
254 | goto csum_failed; | |
255 | ||
d20f7043 | 256 | inode = cb->inode; |
5a9472fe | 257 | ret = check_compressed_csum(BTRFS_I(inode), bio, |
4f024f37 | 258 | (u64)bio->bi_iter.bi_sector << 9); |
d20f7043 CM |
259 | if (ret) |
260 | goto csum_failed; | |
261 | ||
c8b97818 CM |
262 | /* ok, we're the last bio for this extent, lets start |
263 | * the decompression. | |
264 | */ | |
8140dc30 AJ |
265 | ret = btrfs_decompress_bio(cb); |
266 | ||
d20f7043 | 267 | csum_failed: |
c8b97818 CM |
268 | if (ret) |
269 | cb->errors = 1; | |
270 | ||
271 | /* release the compressed pages */ | |
272 | index = 0; | |
273 | for (index = 0; index < cb->nr_pages; index++) { | |
274 | page = cb->compressed_pages[index]; | |
275 | page->mapping = NULL; | |
09cbfeaf | 276 | put_page(page); |
c8b97818 CM |
277 | } |
278 | ||
279 | /* do io completion on the original bio */ | |
771ed689 | 280 | if (cb->errors) { |
c8b97818 | 281 | bio_io_error(cb->orig_bio); |
d20f7043 | 282 | } else { |
2c30c71b | 283 | struct bio_vec *bvec; |
6dc4f100 | 284 | struct bvec_iter_all iter_all; |
d20f7043 CM |
285 | |
286 | /* | |
287 | * we have verified the checksum already, set page | |
288 | * checked so the end_io handlers know about it | |
289 | */ | |
c09abff8 | 290 | ASSERT(!bio_flagged(bio, BIO_CLONED)); |
2b070cfe | 291 | bio_for_each_segment_all(bvec, cb->orig_bio, iter_all) |
d20f7043 | 292 | SetPageChecked(bvec->bv_page); |
2c30c71b | 293 | |
4246a0b6 | 294 | bio_endio(cb->orig_bio); |
d20f7043 | 295 | } |
c8b97818 CM |
296 | |
297 | /* finally free the cb struct */ | |
298 | kfree(cb->compressed_pages); | |
299 | kfree(cb); | |
300 | out: | |
301 | bio_put(bio); | |
302 | } | |
303 | ||
304 | /* | |
305 | * Clear the writeback bits on all of the file | |
306 | * pages for a compressed write | |
307 | */ | |
7bdcefc1 FM |
308 | static noinline void end_compressed_writeback(struct inode *inode, |
309 | const struct compressed_bio *cb) | |
c8b97818 | 310 | { |
09cbfeaf KS |
311 | unsigned long index = cb->start >> PAGE_SHIFT; |
312 | unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT; | |
c8b97818 CM |
313 | struct page *pages[16]; |
314 | unsigned long nr_pages = end_index - index + 1; | |
315 | int i; | |
316 | int ret; | |
317 | ||
7bdcefc1 FM |
318 | if (cb->errors) |
319 | mapping_set_error(inode->i_mapping, -EIO); | |
320 | ||
d397712b | 321 | while (nr_pages > 0) { |
c8b97818 | 322 | ret = find_get_pages_contig(inode->i_mapping, index, |
5b050f04 CM |
323 | min_t(unsigned long, |
324 | nr_pages, ARRAY_SIZE(pages)), pages); | |
c8b97818 CM |
325 | if (ret == 0) { |
326 | nr_pages -= 1; | |
327 | index += 1; | |
328 | continue; | |
329 | } | |
330 | for (i = 0; i < ret; i++) { | |
7bdcefc1 FM |
331 | if (cb->errors) |
332 | SetPageError(pages[i]); | |
c8b97818 | 333 | end_page_writeback(pages[i]); |
09cbfeaf | 334 | put_page(pages[i]); |
c8b97818 CM |
335 | } |
336 | nr_pages -= ret; | |
337 | index += ret; | |
338 | } | |
339 | /* the inode may be gone now */ | |
c8b97818 CM |
340 | } |
341 | ||
342 | /* | |
343 | * do the cleanup once all the compressed pages hit the disk. | |
344 | * This will clear writeback on the file pages and free the compressed | |
345 | * pages. | |
346 | * | |
347 | * This also calls the writeback end hooks for the file pages so that | |
348 | * metadata and checksums can be updated in the file. | |
349 | */ | |
4246a0b6 | 350 | static void end_compressed_bio_write(struct bio *bio) |
c8b97818 | 351 | { |
c8b97818 CM |
352 | struct compressed_bio *cb = bio->bi_private; |
353 | struct inode *inode; | |
354 | struct page *page; | |
355 | unsigned long index; | |
356 | ||
4e4cbee9 | 357 | if (bio->bi_status) |
c8b97818 CM |
358 | cb->errors = 1; |
359 | ||
360 | /* if there are more bios still pending for this compressed | |
361 | * extent, just exit | |
362 | */ | |
a50299ae | 363 | if (!refcount_dec_and_test(&cb->pending_bios)) |
c8b97818 CM |
364 | goto out; |
365 | ||
366 | /* ok, we're the last bio for this extent, step one is to | |
367 | * call back into the FS and do all the end_io operations | |
368 | */ | |
369 | inode = cb->inode; | |
70b99e69 | 370 | cb->compressed_pages[0]->mapping = cb->inode->i_mapping; |
7087a9d8 | 371 | btrfs_writepage_endio_finish_ordered(cb->compressed_pages[0], |
c629732d | 372 | cb->start, cb->start + cb->len - 1, |
6a8d2136 | 373 | bio->bi_status == BLK_STS_OK); |
70b99e69 | 374 | cb->compressed_pages[0]->mapping = NULL; |
c8b97818 | 375 | |
7bdcefc1 | 376 | end_compressed_writeback(inode, cb); |
c8b97818 CM |
377 | /* note, our inode could be gone now */ |
378 | ||
379 | /* | |
380 | * release the compressed pages, these came from alloc_page and | |
381 | * are not attached to the inode at all | |
382 | */ | |
383 | index = 0; | |
384 | for (index = 0; index < cb->nr_pages; index++) { | |
385 | page = cb->compressed_pages[index]; | |
386 | page->mapping = NULL; | |
09cbfeaf | 387 | put_page(page); |
c8b97818 CM |
388 | } |
389 | ||
390 | /* finally free the cb struct */ | |
391 | kfree(cb->compressed_pages); | |
392 | kfree(cb); | |
393 | out: | |
394 | bio_put(bio); | |
395 | } | |
396 | ||
397 | /* | |
398 | * worker function to build and submit bios for previously compressed pages. | |
399 | * The corresponding pages in the inode should be marked for writeback | |
400 | * and the compressed pages should have a reference on them for dropping | |
401 | * when the IO is complete. | |
402 | * | |
403 | * This also checksums the file bytes and gets things ready for | |
404 | * the end io hooks. | |
405 | */ | |
c7ee1819 | 406 | blk_status_t btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start, |
c8b97818 CM |
407 | unsigned long len, u64 disk_start, |
408 | unsigned long compressed_len, | |
409 | struct page **compressed_pages, | |
f82b7359 | 410 | unsigned long nr_pages, |
ec39f769 CM |
411 | unsigned int write_flags, |
412 | struct cgroup_subsys_state *blkcg_css) | |
c8b97818 | 413 | { |
c7ee1819 | 414 | struct btrfs_fs_info *fs_info = inode->root->fs_info; |
c8b97818 | 415 | struct bio *bio = NULL; |
c8b97818 CM |
416 | struct compressed_bio *cb; |
417 | unsigned long bytes_left; | |
306e16ce | 418 | int pg_index = 0; |
c8b97818 CM |
419 | struct page *page; |
420 | u64 first_byte = disk_start; | |
4e4cbee9 | 421 | blk_status_t ret; |
c7ee1819 | 422 | int skip_sum = inode->flags & BTRFS_INODE_NODATASUM; |
c8b97818 | 423 | |
fdb1e121 | 424 | WARN_ON(!PAGE_ALIGNED(start)); |
2ff7e61e | 425 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
dac97e51 | 426 | if (!cb) |
4e4cbee9 | 427 | return BLK_STS_RESOURCE; |
a50299ae | 428 | refcount_set(&cb->pending_bios, 0); |
c8b97818 | 429 | cb->errors = 0; |
c7ee1819 | 430 | cb->inode = &inode->vfs_inode; |
c8b97818 CM |
431 | cb->start = start; |
432 | cb->len = len; | |
d20f7043 | 433 | cb->mirror_num = 0; |
c8b97818 CM |
434 | cb->compressed_pages = compressed_pages; |
435 | cb->compressed_len = compressed_len; | |
436 | cb->orig_bio = NULL; | |
437 | cb->nr_pages = nr_pages; | |
438 | ||
e749af44 | 439 | bio = btrfs_bio_alloc(first_byte); |
f82b7359 | 440 | bio->bi_opf = REQ_OP_WRITE | write_flags; |
c8b97818 CM |
441 | bio->bi_private = cb; |
442 | bio->bi_end_io = end_compressed_bio_write; | |
ec39f769 CM |
443 | |
444 | if (blkcg_css) { | |
445 | bio->bi_opf |= REQ_CGROUP_PUNT; | |
46bcff2b | 446 | kthread_associate_blkcg(blkcg_css); |
ec39f769 | 447 | } |
a50299ae | 448 | refcount_set(&cb->pending_bios, 1); |
c8b97818 CM |
449 | |
450 | /* create and submit bios for the compressed pages */ | |
451 | bytes_left = compressed_len; | |
306e16ce | 452 | for (pg_index = 0; pg_index < cb->nr_pages; pg_index++) { |
4e4cbee9 CH |
453 | int submit = 0; |
454 | ||
306e16ce | 455 | page = compressed_pages[pg_index]; |
c7ee1819 | 456 | page->mapping = inode->vfs_inode.i_mapping; |
4f024f37 | 457 | if (bio->bi_iter.bi_size) |
da12fe54 NB |
458 | submit = btrfs_bio_fits_in_stripe(page, PAGE_SIZE, bio, |
459 | 0); | |
c8b97818 | 460 | |
70b99e69 | 461 | page->mapping = NULL; |
4e4cbee9 | 462 | if (submit || bio_add_page(bio, page, PAGE_SIZE, 0) < |
09cbfeaf | 463 | PAGE_SIZE) { |
af09abfe CM |
464 | /* |
465 | * inc the count before we submit the bio so | |
466 | * we know the end IO handler won't happen before | |
467 | * we inc the count. Otherwise, the cb might get | |
468 | * freed before we're done setting it up | |
469 | */ | |
a50299ae | 470 | refcount_inc(&cb->pending_bios); |
0b246afa JM |
471 | ret = btrfs_bio_wq_end_io(fs_info, bio, |
472 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 473 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 474 | |
e55179b3 | 475 | if (!skip_sum) { |
c7ee1819 | 476 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 477 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 478 | } |
d20f7043 | 479 | |
08635bae | 480 | ret = btrfs_map_bio(fs_info, bio, 0); |
f5daf2c7 | 481 | if (ret) { |
4e4cbee9 | 482 | bio->bi_status = ret; |
f5daf2c7 LB |
483 | bio_endio(bio); |
484 | } | |
c8b97818 | 485 | |
e749af44 | 486 | bio = btrfs_bio_alloc(first_byte); |
f82b7359 | 487 | bio->bi_opf = REQ_OP_WRITE | write_flags; |
c8b97818 CM |
488 | bio->bi_private = cb; |
489 | bio->bi_end_io = end_compressed_bio_write; | |
46bcff2b | 490 | if (blkcg_css) |
7b62e66c | 491 | bio->bi_opf |= REQ_CGROUP_PUNT; |
09cbfeaf | 492 | bio_add_page(bio, page, PAGE_SIZE, 0); |
c8b97818 | 493 | } |
09cbfeaf | 494 | if (bytes_left < PAGE_SIZE) { |
0b246afa | 495 | btrfs_info(fs_info, |
efe120a0 | 496 | "bytes left %lu compress len %lu nr %lu", |
cfbc246e CM |
497 | bytes_left, cb->compressed_len, cb->nr_pages); |
498 | } | |
09cbfeaf KS |
499 | bytes_left -= PAGE_SIZE; |
500 | first_byte += PAGE_SIZE; | |
771ed689 | 501 | cond_resched(); |
c8b97818 | 502 | } |
c8b97818 | 503 | |
0b246afa | 504 | ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 505 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 506 | |
e55179b3 | 507 | if (!skip_sum) { |
c7ee1819 | 508 | ret = btrfs_csum_one_bio(inode, bio, start, 1); |
79787eaa | 509 | BUG_ON(ret); /* -ENOMEM */ |
e55179b3 | 510 | } |
d20f7043 | 511 | |
08635bae | 512 | ret = btrfs_map_bio(fs_info, bio, 0); |
f5daf2c7 | 513 | if (ret) { |
4e4cbee9 | 514 | bio->bi_status = ret; |
f5daf2c7 LB |
515 | bio_endio(bio); |
516 | } | |
c8b97818 | 517 | |
46bcff2b DZ |
518 | if (blkcg_css) |
519 | kthread_associate_blkcg(NULL); | |
520 | ||
c8b97818 CM |
521 | return 0; |
522 | } | |
523 | ||
2a4d0c90 CH |
524 | static u64 bio_end_offset(struct bio *bio) |
525 | { | |
c45a8f2d | 526 | struct bio_vec *last = bio_last_bvec_all(bio); |
2a4d0c90 CH |
527 | |
528 | return page_offset(last->bv_page) + last->bv_len + last->bv_offset; | |
529 | } | |
530 | ||
771ed689 CM |
531 | static noinline int add_ra_bio_pages(struct inode *inode, |
532 | u64 compressed_end, | |
533 | struct compressed_bio *cb) | |
534 | { | |
535 | unsigned long end_index; | |
306e16ce | 536 | unsigned long pg_index; |
771ed689 CM |
537 | u64 last_offset; |
538 | u64 isize = i_size_read(inode); | |
539 | int ret; | |
540 | struct page *page; | |
541 | unsigned long nr_pages = 0; | |
542 | struct extent_map *em; | |
543 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
544 | struct extent_map_tree *em_tree; |
545 | struct extent_io_tree *tree; | |
546 | u64 end; | |
547 | int misses = 0; | |
548 | ||
2a4d0c90 | 549 | last_offset = bio_end_offset(cb->orig_bio); |
771ed689 CM |
550 | em_tree = &BTRFS_I(inode)->extent_tree; |
551 | tree = &BTRFS_I(inode)->io_tree; | |
552 | ||
553 | if (isize == 0) | |
554 | return 0; | |
555 | ||
09cbfeaf | 556 | end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; |
771ed689 | 557 | |
d397712b | 558 | while (last_offset < compressed_end) { |
09cbfeaf | 559 | pg_index = last_offset >> PAGE_SHIFT; |
771ed689 | 560 | |
306e16ce | 561 | if (pg_index > end_index) |
771ed689 CM |
562 | break; |
563 | ||
0a943c65 | 564 | page = xa_load(&mapping->i_pages, pg_index); |
3159f943 | 565 | if (page && !xa_is_value(page)) { |
771ed689 CM |
566 | misses++; |
567 | if (misses > 4) | |
568 | break; | |
569 | goto next; | |
570 | } | |
571 | ||
c62d2555 MH |
572 | page = __page_cache_alloc(mapping_gfp_constraint(mapping, |
573 | ~__GFP_FS)); | |
771ed689 CM |
574 | if (!page) |
575 | break; | |
576 | ||
c62d2555 | 577 | if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) { |
09cbfeaf | 578 | put_page(page); |
771ed689 CM |
579 | goto next; |
580 | } | |
581 | ||
09cbfeaf | 582 | end = last_offset + PAGE_SIZE - 1; |
771ed689 CM |
583 | /* |
584 | * at this point, we have a locked page in the page cache | |
585 | * for these bytes in the file. But, we have to make | |
586 | * sure they map to this compressed extent on disk. | |
587 | */ | |
588 | set_page_extent_mapped(page); | |
d0082371 | 589 | lock_extent(tree, last_offset, end); |
890871be | 590 | read_lock(&em_tree->lock); |
771ed689 | 591 | em = lookup_extent_mapping(em_tree, last_offset, |
09cbfeaf | 592 | PAGE_SIZE); |
890871be | 593 | read_unlock(&em_tree->lock); |
771ed689 CM |
594 | |
595 | if (!em || last_offset < em->start || | |
09cbfeaf | 596 | (last_offset + PAGE_SIZE > extent_map_end(em)) || |
4f024f37 | 597 | (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) { |
771ed689 | 598 | free_extent_map(em); |
d0082371 | 599 | unlock_extent(tree, last_offset, end); |
771ed689 | 600 | unlock_page(page); |
09cbfeaf | 601 | put_page(page); |
771ed689 CM |
602 | break; |
603 | } | |
604 | free_extent_map(em); | |
605 | ||
606 | if (page->index == end_index) { | |
607 | char *userpage; | |
7073017a | 608 | size_t zero_offset = offset_in_page(isize); |
771ed689 CM |
609 | |
610 | if (zero_offset) { | |
611 | int zeros; | |
09cbfeaf | 612 | zeros = PAGE_SIZE - zero_offset; |
7ac687d9 | 613 | userpage = kmap_atomic(page); |
771ed689 CM |
614 | memset(userpage + zero_offset, 0, zeros); |
615 | flush_dcache_page(page); | |
7ac687d9 | 616 | kunmap_atomic(userpage); |
771ed689 CM |
617 | } |
618 | } | |
619 | ||
620 | ret = bio_add_page(cb->orig_bio, page, | |
09cbfeaf | 621 | PAGE_SIZE, 0); |
771ed689 | 622 | |
09cbfeaf | 623 | if (ret == PAGE_SIZE) { |
771ed689 | 624 | nr_pages++; |
09cbfeaf | 625 | put_page(page); |
771ed689 | 626 | } else { |
d0082371 | 627 | unlock_extent(tree, last_offset, end); |
771ed689 | 628 | unlock_page(page); |
09cbfeaf | 629 | put_page(page); |
771ed689 CM |
630 | break; |
631 | } | |
632 | next: | |
09cbfeaf | 633 | last_offset += PAGE_SIZE; |
771ed689 | 634 | } |
771ed689 CM |
635 | return 0; |
636 | } | |
637 | ||
c8b97818 CM |
638 | /* |
639 | * for a compressed read, the bio we get passed has all the inode pages | |
640 | * in it. We don't actually do IO on those pages but allocate new ones | |
641 | * to hold the compressed pages on disk. | |
642 | * | |
4f024f37 | 643 | * bio->bi_iter.bi_sector points to the compressed extent on disk |
c8b97818 | 644 | * bio->bi_io_vec points to all of the inode pages |
c8b97818 CM |
645 | * |
646 | * After the compressed pages are read, we copy the bytes into the | |
647 | * bio we were passed and then call the bio end_io calls | |
648 | */ | |
4e4cbee9 | 649 | blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio, |
c8b97818 CM |
650 | int mirror_num, unsigned long bio_flags) |
651 | { | |
0b246afa | 652 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
c8b97818 CM |
653 | struct extent_map_tree *em_tree; |
654 | struct compressed_bio *cb; | |
c8b97818 CM |
655 | unsigned long compressed_len; |
656 | unsigned long nr_pages; | |
306e16ce | 657 | unsigned long pg_index; |
c8b97818 | 658 | struct page *page; |
c8b97818 | 659 | struct bio *comp_bio; |
4f024f37 | 660 | u64 cur_disk_byte = (u64)bio->bi_iter.bi_sector << 9; |
e04ca626 CM |
661 | u64 em_len; |
662 | u64 em_start; | |
c8b97818 | 663 | struct extent_map *em; |
4e4cbee9 | 664 | blk_status_t ret = BLK_STS_RESOURCE; |
15e3004a | 665 | int faili = 0; |
10fe6ca8 JT |
666 | const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); |
667 | u8 *sums; | |
c8b97818 | 668 | |
c8b97818 CM |
669 | em_tree = &BTRFS_I(inode)->extent_tree; |
670 | ||
671 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 672 | read_lock(&em_tree->lock); |
c8b97818 | 673 | em = lookup_extent_mapping(em_tree, |
263663cd | 674 | page_offset(bio_first_page_all(bio)), |
09cbfeaf | 675 | PAGE_SIZE); |
890871be | 676 | read_unlock(&em_tree->lock); |
285190d9 | 677 | if (!em) |
4e4cbee9 | 678 | return BLK_STS_IOERR; |
c8b97818 | 679 | |
d20f7043 | 680 | compressed_len = em->block_len; |
2ff7e61e | 681 | cb = kmalloc(compressed_bio_size(fs_info, compressed_len), GFP_NOFS); |
6b82ce8d | 682 | if (!cb) |
683 | goto out; | |
684 | ||
a50299ae | 685 | refcount_set(&cb->pending_bios, 0); |
c8b97818 CM |
686 | cb->errors = 0; |
687 | cb->inode = inode; | |
d20f7043 | 688 | cb->mirror_num = mirror_num; |
10fe6ca8 | 689 | sums = cb->sums; |
c8b97818 | 690 | |
ff5b7ee3 | 691 | cb->start = em->orig_start; |
e04ca626 CM |
692 | em_len = em->len; |
693 | em_start = em->start; | |
d20f7043 | 694 | |
c8b97818 | 695 | free_extent_map(em); |
e04ca626 | 696 | em = NULL; |
c8b97818 | 697 | |
81381053 | 698 | cb->len = bio->bi_iter.bi_size; |
c8b97818 | 699 | cb->compressed_len = compressed_len; |
261507a0 | 700 | cb->compress_type = extent_compress_type(bio_flags); |
c8b97818 CM |
701 | cb->orig_bio = bio; |
702 | ||
09cbfeaf | 703 | nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); |
31e818fe | 704 | cb->compressed_pages = kcalloc(nr_pages, sizeof(struct page *), |
c8b97818 | 705 | GFP_NOFS); |
6b82ce8d | 706 | if (!cb->compressed_pages) |
707 | goto fail1; | |
708 | ||
306e16ce DS |
709 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
710 | cb->compressed_pages[pg_index] = alloc_page(GFP_NOFS | | |
c8b97818 | 711 | __GFP_HIGHMEM); |
15e3004a JB |
712 | if (!cb->compressed_pages[pg_index]) { |
713 | faili = pg_index - 1; | |
0e9350de | 714 | ret = BLK_STS_RESOURCE; |
6b82ce8d | 715 | goto fail2; |
15e3004a | 716 | } |
c8b97818 | 717 | } |
15e3004a | 718 | faili = nr_pages - 1; |
c8b97818 CM |
719 | cb->nr_pages = nr_pages; |
720 | ||
7f042a83 | 721 | add_ra_bio_pages(inode, em_start + em_len, cb); |
771ed689 | 722 | |
771ed689 | 723 | /* include any pages we added in add_ra-bio_pages */ |
81381053 | 724 | cb->len = bio->bi_iter.bi_size; |
771ed689 | 725 | |
e749af44 | 726 | comp_bio = btrfs_bio_alloc(cur_disk_byte); |
ebcc3263 | 727 | comp_bio->bi_opf = REQ_OP_READ; |
c8b97818 CM |
728 | comp_bio->bi_private = cb; |
729 | comp_bio->bi_end_io = end_compressed_bio_read; | |
a50299ae | 730 | refcount_set(&cb->pending_bios, 1); |
c8b97818 | 731 | |
306e16ce | 732 | for (pg_index = 0; pg_index < nr_pages; pg_index++) { |
4e4cbee9 CH |
733 | int submit = 0; |
734 | ||
306e16ce | 735 | page = cb->compressed_pages[pg_index]; |
c8b97818 | 736 | page->mapping = inode->i_mapping; |
09cbfeaf | 737 | page->index = em_start >> PAGE_SHIFT; |
d20f7043 | 738 | |
4f024f37 | 739 | if (comp_bio->bi_iter.bi_size) |
da12fe54 NB |
740 | submit = btrfs_bio_fits_in_stripe(page, PAGE_SIZE, |
741 | comp_bio, 0); | |
c8b97818 | 742 | |
70b99e69 | 743 | page->mapping = NULL; |
4e4cbee9 | 744 | if (submit || bio_add_page(comp_bio, page, PAGE_SIZE, 0) < |
09cbfeaf | 745 | PAGE_SIZE) { |
10fe6ca8 JT |
746 | unsigned int nr_sectors; |
747 | ||
0b246afa JM |
748 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, |
749 | BTRFS_WQ_ENDIO_DATA); | |
79787eaa | 750 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 751 | |
af09abfe CM |
752 | /* |
753 | * inc the count before we submit the bio so | |
754 | * we know the end IO handler won't happen before | |
755 | * we inc the count. Otherwise, the cb might get | |
756 | * freed before we're done setting it up | |
757 | */ | |
a50299ae | 758 | refcount_inc(&cb->pending_bios); |
af09abfe | 759 | |
6cbff00f | 760 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
2ff7e61e | 761 | ret = btrfs_lookup_bio_sums(inode, comp_bio, |
db72e47f | 762 | (u64)-1, sums); |
79787eaa | 763 | BUG_ON(ret); /* -ENOMEM */ |
d20f7043 | 764 | } |
10fe6ca8 JT |
765 | |
766 | nr_sectors = DIV_ROUND_UP(comp_bio->bi_iter.bi_size, | |
767 | fs_info->sectorsize); | |
768 | sums += csum_size * nr_sectors; | |
d20f7043 | 769 | |
08635bae | 770 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num); |
4246a0b6 | 771 | if (ret) { |
4e4cbee9 | 772 | comp_bio->bi_status = ret; |
4246a0b6 CH |
773 | bio_endio(comp_bio); |
774 | } | |
c8b97818 | 775 | |
e749af44 | 776 | comp_bio = btrfs_bio_alloc(cur_disk_byte); |
ebcc3263 | 777 | comp_bio->bi_opf = REQ_OP_READ; |
771ed689 CM |
778 | comp_bio->bi_private = cb; |
779 | comp_bio->bi_end_io = end_compressed_bio_read; | |
780 | ||
09cbfeaf | 781 | bio_add_page(comp_bio, page, PAGE_SIZE, 0); |
c8b97818 | 782 | } |
09cbfeaf | 783 | cur_disk_byte += PAGE_SIZE; |
c8b97818 | 784 | } |
c8b97818 | 785 | |
0b246afa | 786 | ret = btrfs_bio_wq_end_io(fs_info, comp_bio, BTRFS_WQ_ENDIO_DATA); |
79787eaa | 787 | BUG_ON(ret); /* -ENOMEM */ |
c8b97818 | 788 | |
c2db1073 | 789 | if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) { |
db72e47f | 790 | ret = btrfs_lookup_bio_sums(inode, comp_bio, (u64)-1, sums); |
79787eaa | 791 | BUG_ON(ret); /* -ENOMEM */ |
c2db1073 | 792 | } |
d20f7043 | 793 | |
08635bae | 794 | ret = btrfs_map_bio(fs_info, comp_bio, mirror_num); |
4246a0b6 | 795 | if (ret) { |
4e4cbee9 | 796 | comp_bio->bi_status = ret; |
4246a0b6 CH |
797 | bio_endio(comp_bio); |
798 | } | |
c8b97818 | 799 | |
c8b97818 | 800 | return 0; |
6b82ce8d | 801 | |
802 | fail2: | |
15e3004a JB |
803 | while (faili >= 0) { |
804 | __free_page(cb->compressed_pages[faili]); | |
805 | faili--; | |
806 | } | |
6b82ce8d | 807 | |
808 | kfree(cb->compressed_pages); | |
809 | fail1: | |
810 | kfree(cb); | |
811 | out: | |
812 | free_extent_map(em); | |
813 | return ret; | |
c8b97818 | 814 | } |
261507a0 | 815 | |
17b5a6c1 TT |
816 | /* |
817 | * Heuristic uses systematic sampling to collect data from the input data | |
818 | * range, the logic can be tuned by the following constants: | |
819 | * | |
820 | * @SAMPLING_READ_SIZE - how many bytes will be copied from for each sample | |
821 | * @SAMPLING_INTERVAL - range from which the sampled data can be collected | |
822 | */ | |
823 | #define SAMPLING_READ_SIZE (16) | |
824 | #define SAMPLING_INTERVAL (256) | |
825 | ||
826 | /* | |
827 | * For statistical analysis of the input data we consider bytes that form a | |
828 | * Galois Field of 256 objects. Each object has an attribute count, ie. how | |
829 | * many times the object appeared in the sample. | |
830 | */ | |
831 | #define BUCKET_SIZE (256) | |
832 | ||
833 | /* | |
834 | * The size of the sample is based on a statistical sampling rule of thumb. | |
835 | * The common way is to perform sampling tests as long as the number of | |
836 | * elements in each cell is at least 5. | |
837 | * | |
838 | * Instead of 5, we choose 32 to obtain more accurate results. | |
839 | * If the data contain the maximum number of symbols, which is 256, we obtain a | |
840 | * sample size bound by 8192. | |
841 | * | |
842 | * For a sample of at most 8KB of data per data range: 16 consecutive bytes | |
843 | * from up to 512 locations. | |
844 | */ | |
845 | #define MAX_SAMPLE_SIZE (BTRFS_MAX_UNCOMPRESSED * \ | |
846 | SAMPLING_READ_SIZE / SAMPLING_INTERVAL) | |
847 | ||
848 | struct bucket_item { | |
849 | u32 count; | |
850 | }; | |
4e439a0b TT |
851 | |
852 | struct heuristic_ws { | |
17b5a6c1 TT |
853 | /* Partial copy of input data */ |
854 | u8 *sample; | |
a440d48c | 855 | u32 sample_size; |
17b5a6c1 TT |
856 | /* Buckets store counters for each byte value */ |
857 | struct bucket_item *bucket; | |
440c840c TT |
858 | /* Sorting buffer */ |
859 | struct bucket_item *bucket_b; | |
4e439a0b TT |
860 | struct list_head list; |
861 | }; | |
862 | ||
92ee5530 DZ |
863 | static struct workspace_manager heuristic_wsm; |
864 | ||
4e439a0b TT |
865 | static void free_heuristic_ws(struct list_head *ws) |
866 | { | |
867 | struct heuristic_ws *workspace; | |
868 | ||
869 | workspace = list_entry(ws, struct heuristic_ws, list); | |
870 | ||
17b5a6c1 TT |
871 | kvfree(workspace->sample); |
872 | kfree(workspace->bucket); | |
440c840c | 873 | kfree(workspace->bucket_b); |
4e439a0b TT |
874 | kfree(workspace); |
875 | } | |
876 | ||
7bf49943 | 877 | static struct list_head *alloc_heuristic_ws(unsigned int level) |
4e439a0b TT |
878 | { |
879 | struct heuristic_ws *ws; | |
880 | ||
881 | ws = kzalloc(sizeof(*ws), GFP_KERNEL); | |
882 | if (!ws) | |
883 | return ERR_PTR(-ENOMEM); | |
884 | ||
17b5a6c1 TT |
885 | ws->sample = kvmalloc(MAX_SAMPLE_SIZE, GFP_KERNEL); |
886 | if (!ws->sample) | |
887 | goto fail; | |
888 | ||
889 | ws->bucket = kcalloc(BUCKET_SIZE, sizeof(*ws->bucket), GFP_KERNEL); | |
890 | if (!ws->bucket) | |
891 | goto fail; | |
4e439a0b | 892 | |
440c840c TT |
893 | ws->bucket_b = kcalloc(BUCKET_SIZE, sizeof(*ws->bucket_b), GFP_KERNEL); |
894 | if (!ws->bucket_b) | |
895 | goto fail; | |
896 | ||
17b5a6c1 | 897 | INIT_LIST_HEAD(&ws->list); |
4e439a0b | 898 | return &ws->list; |
17b5a6c1 TT |
899 | fail: |
900 | free_heuristic_ws(&ws->list); | |
901 | return ERR_PTR(-ENOMEM); | |
4e439a0b TT |
902 | } |
903 | ||
ca4ac360 | 904 | const struct btrfs_compress_op btrfs_heuristic_compress = { |
be951045 | 905 | .workspace_manager = &heuristic_wsm, |
ca4ac360 DZ |
906 | }; |
907 | ||
e8c9f186 | 908 | static const struct btrfs_compress_op * const btrfs_compress_op[] = { |
ca4ac360 DZ |
909 | /* The heuristic is represented as compression type 0 */ |
910 | &btrfs_heuristic_compress, | |
261507a0 | 911 | &btrfs_zlib_compress, |
a6fa6fae | 912 | &btrfs_lzo_compress, |
5c1aab1d | 913 | &btrfs_zstd_compress, |
261507a0 LZ |
914 | }; |
915 | ||
c778df14 DS |
916 | static struct list_head *alloc_workspace(int type, unsigned int level) |
917 | { | |
918 | switch (type) { | |
919 | case BTRFS_COMPRESS_NONE: return alloc_heuristic_ws(level); | |
920 | case BTRFS_COMPRESS_ZLIB: return zlib_alloc_workspace(level); | |
921 | case BTRFS_COMPRESS_LZO: return lzo_alloc_workspace(level); | |
922 | case BTRFS_COMPRESS_ZSTD: return zstd_alloc_workspace(level); | |
923 | default: | |
924 | /* | |
925 | * This can't happen, the type is validated several times | |
926 | * before we get here. | |
927 | */ | |
928 | BUG(); | |
929 | } | |
930 | } | |
931 | ||
1e002351 DS |
932 | static void free_workspace(int type, struct list_head *ws) |
933 | { | |
934 | switch (type) { | |
935 | case BTRFS_COMPRESS_NONE: return free_heuristic_ws(ws); | |
936 | case BTRFS_COMPRESS_ZLIB: return zlib_free_workspace(ws); | |
937 | case BTRFS_COMPRESS_LZO: return lzo_free_workspace(ws); | |
938 | case BTRFS_COMPRESS_ZSTD: return zstd_free_workspace(ws); | |
939 | default: | |
940 | /* | |
941 | * This can't happen, the type is validated several times | |
942 | * before we get here. | |
943 | */ | |
944 | BUG(); | |
945 | } | |
946 | } | |
947 | ||
d5517033 | 948 | static void btrfs_init_workspace_manager(int type) |
261507a0 | 949 | { |
0cf25213 | 950 | struct workspace_manager *wsm; |
4e439a0b | 951 | struct list_head *workspace; |
261507a0 | 952 | |
0cf25213 | 953 | wsm = btrfs_compress_op[type]->workspace_manager; |
92ee5530 DZ |
954 | INIT_LIST_HEAD(&wsm->idle_ws); |
955 | spin_lock_init(&wsm->ws_lock); | |
956 | atomic_set(&wsm->total_ws, 0); | |
957 | init_waitqueue_head(&wsm->ws_wait); | |
f77dd0d6 | 958 | |
1666edab DZ |
959 | /* |
960 | * Preallocate one workspace for each compression type so we can | |
961 | * guarantee forward progress in the worst case | |
962 | */ | |
c778df14 | 963 | workspace = alloc_workspace(type, 0); |
1666edab DZ |
964 | if (IS_ERR(workspace)) { |
965 | pr_warn( | |
966 | "BTRFS: cannot preallocate compression workspace, will try later\n"); | |
967 | } else { | |
92ee5530 DZ |
968 | atomic_set(&wsm->total_ws, 1); |
969 | wsm->free_ws = 1; | |
970 | list_add(workspace, &wsm->idle_ws); | |
1666edab DZ |
971 | } |
972 | } | |
973 | ||
2510307e | 974 | static void btrfs_cleanup_workspace_manager(int type) |
1666edab | 975 | { |
2dba7143 | 976 | struct workspace_manager *wsman; |
1666edab DZ |
977 | struct list_head *ws; |
978 | ||
2dba7143 | 979 | wsman = btrfs_compress_op[type]->workspace_manager; |
1666edab DZ |
980 | while (!list_empty(&wsman->idle_ws)) { |
981 | ws = wsman->idle_ws.next; | |
982 | list_del(ws); | |
1e002351 | 983 | free_workspace(type, ws); |
1666edab | 984 | atomic_dec(&wsman->total_ws); |
261507a0 | 985 | } |
261507a0 LZ |
986 | } |
987 | ||
988 | /* | |
e721e49d DS |
989 | * This finds an available workspace or allocates a new one. |
990 | * If it's not possible to allocate a new one, waits until there's one. | |
991 | * Preallocation makes a forward progress guarantees and we do not return | |
992 | * errors. | |
261507a0 | 993 | */ |
5907a9bb | 994 | struct list_head *btrfs_get_workspace(int type, unsigned int level) |
261507a0 | 995 | { |
5907a9bb | 996 | struct workspace_manager *wsm; |
261507a0 LZ |
997 | struct list_head *workspace; |
998 | int cpus = num_online_cpus(); | |
fe308533 | 999 | unsigned nofs_flag; |
4e439a0b TT |
1000 | struct list_head *idle_ws; |
1001 | spinlock_t *ws_lock; | |
1002 | atomic_t *total_ws; | |
1003 | wait_queue_head_t *ws_wait; | |
1004 | int *free_ws; | |
1005 | ||
5907a9bb | 1006 | wsm = btrfs_compress_op[type]->workspace_manager; |
92ee5530 DZ |
1007 | idle_ws = &wsm->idle_ws; |
1008 | ws_lock = &wsm->ws_lock; | |
1009 | total_ws = &wsm->total_ws; | |
1010 | ws_wait = &wsm->ws_wait; | |
1011 | free_ws = &wsm->free_ws; | |
261507a0 | 1012 | |
261507a0 | 1013 | again: |
d9187649 BL |
1014 | spin_lock(ws_lock); |
1015 | if (!list_empty(idle_ws)) { | |
1016 | workspace = idle_ws->next; | |
261507a0 | 1017 | list_del(workspace); |
6ac10a6a | 1018 | (*free_ws)--; |
d9187649 | 1019 | spin_unlock(ws_lock); |
261507a0 LZ |
1020 | return workspace; |
1021 | ||
1022 | } | |
6ac10a6a | 1023 | if (atomic_read(total_ws) > cpus) { |
261507a0 LZ |
1024 | DEFINE_WAIT(wait); |
1025 | ||
d9187649 BL |
1026 | spin_unlock(ws_lock); |
1027 | prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE); | |
6ac10a6a | 1028 | if (atomic_read(total_ws) > cpus && !*free_ws) |
261507a0 | 1029 | schedule(); |
d9187649 | 1030 | finish_wait(ws_wait, &wait); |
261507a0 LZ |
1031 | goto again; |
1032 | } | |
6ac10a6a | 1033 | atomic_inc(total_ws); |
d9187649 | 1034 | spin_unlock(ws_lock); |
261507a0 | 1035 | |
fe308533 DS |
1036 | /* |
1037 | * Allocation helpers call vmalloc that can't use GFP_NOFS, so we have | |
1038 | * to turn it off here because we might get called from the restricted | |
1039 | * context of btrfs_compress_bio/btrfs_compress_pages | |
1040 | */ | |
1041 | nofs_flag = memalloc_nofs_save(); | |
c778df14 | 1042 | workspace = alloc_workspace(type, level); |
fe308533 DS |
1043 | memalloc_nofs_restore(nofs_flag); |
1044 | ||
261507a0 | 1045 | if (IS_ERR(workspace)) { |
6ac10a6a | 1046 | atomic_dec(total_ws); |
d9187649 | 1047 | wake_up(ws_wait); |
e721e49d DS |
1048 | |
1049 | /* | |
1050 | * Do not return the error but go back to waiting. There's a | |
1051 | * workspace preallocated for each type and the compression | |
1052 | * time is bounded so we get to a workspace eventually. This | |
1053 | * makes our caller's life easier. | |
52356716 DS |
1054 | * |
1055 | * To prevent silent and low-probability deadlocks (when the | |
1056 | * initial preallocation fails), check if there are any | |
1057 | * workspaces at all. | |
e721e49d | 1058 | */ |
52356716 DS |
1059 | if (atomic_read(total_ws) == 0) { |
1060 | static DEFINE_RATELIMIT_STATE(_rs, | |
1061 | /* once per minute */ 60 * HZ, | |
1062 | /* no burst */ 1); | |
1063 | ||
1064 | if (__ratelimit(&_rs)) { | |
ab8d0fc4 | 1065 | pr_warn("BTRFS: no compression workspaces, low memory, retrying\n"); |
52356716 DS |
1066 | } |
1067 | } | |
e721e49d | 1068 | goto again; |
261507a0 LZ |
1069 | } |
1070 | return workspace; | |
1071 | } | |
1072 | ||
7bf49943 | 1073 | static struct list_head *get_workspace(int type, int level) |
929f4baf | 1074 | { |
6a0d1272 | 1075 | switch (type) { |
5907a9bb | 1076 | case BTRFS_COMPRESS_NONE: return btrfs_get_workspace(type, level); |
6a0d1272 | 1077 | case BTRFS_COMPRESS_ZLIB: return zlib_get_workspace(level); |
5907a9bb | 1078 | case BTRFS_COMPRESS_LZO: return btrfs_get_workspace(type, level); |
6a0d1272 DS |
1079 | case BTRFS_COMPRESS_ZSTD: return zstd_get_workspace(level); |
1080 | default: | |
1081 | /* | |
1082 | * This can't happen, the type is validated several times | |
1083 | * before we get here. | |
1084 | */ | |
1085 | BUG(); | |
1086 | } | |
929f4baf DZ |
1087 | } |
1088 | ||
261507a0 LZ |
1089 | /* |
1090 | * put a workspace struct back on the list or free it if we have enough | |
1091 | * idle ones sitting around | |
1092 | */ | |
a3bbd2a9 | 1093 | void btrfs_put_workspace(int type, struct list_head *ws) |
261507a0 | 1094 | { |
a3bbd2a9 | 1095 | struct workspace_manager *wsm; |
4e439a0b TT |
1096 | struct list_head *idle_ws; |
1097 | spinlock_t *ws_lock; | |
1098 | atomic_t *total_ws; | |
1099 | wait_queue_head_t *ws_wait; | |
1100 | int *free_ws; | |
1101 | ||
a3bbd2a9 | 1102 | wsm = btrfs_compress_op[type]->workspace_manager; |
92ee5530 DZ |
1103 | idle_ws = &wsm->idle_ws; |
1104 | ws_lock = &wsm->ws_lock; | |
1105 | total_ws = &wsm->total_ws; | |
1106 | ws_wait = &wsm->ws_wait; | |
1107 | free_ws = &wsm->free_ws; | |
d9187649 BL |
1108 | |
1109 | spin_lock(ws_lock); | |
26b28dce | 1110 | if (*free_ws <= num_online_cpus()) { |
929f4baf | 1111 | list_add(ws, idle_ws); |
6ac10a6a | 1112 | (*free_ws)++; |
d9187649 | 1113 | spin_unlock(ws_lock); |
261507a0 LZ |
1114 | goto wake; |
1115 | } | |
d9187649 | 1116 | spin_unlock(ws_lock); |
261507a0 | 1117 | |
1e002351 | 1118 | free_workspace(type, ws); |
6ac10a6a | 1119 | atomic_dec(total_ws); |
261507a0 | 1120 | wake: |
093258e6 | 1121 | cond_wake_up(ws_wait); |
261507a0 LZ |
1122 | } |
1123 | ||
929f4baf DZ |
1124 | static void put_workspace(int type, struct list_head *ws) |
1125 | { | |
bd3a5287 | 1126 | switch (type) { |
a3bbd2a9 DS |
1127 | case BTRFS_COMPRESS_NONE: return btrfs_put_workspace(type, ws); |
1128 | case BTRFS_COMPRESS_ZLIB: return btrfs_put_workspace(type, ws); | |
1129 | case BTRFS_COMPRESS_LZO: return btrfs_put_workspace(type, ws); | |
bd3a5287 DS |
1130 | case BTRFS_COMPRESS_ZSTD: return zstd_put_workspace(ws); |
1131 | default: | |
1132 | /* | |
1133 | * This can't happen, the type is validated several times | |
1134 | * before we get here. | |
1135 | */ | |
1136 | BUG(); | |
1137 | } | |
929f4baf DZ |
1138 | } |
1139 | ||
adbab642 AJ |
1140 | /* |
1141 | * Adjust @level according to the limits of the compression algorithm or | |
1142 | * fallback to default | |
1143 | */ | |
1144 | static unsigned int btrfs_compress_set_level(int type, unsigned level) | |
1145 | { | |
1146 | const struct btrfs_compress_op *ops = btrfs_compress_op[type]; | |
1147 | ||
1148 | if (level == 0) | |
1149 | level = ops->default_level; | |
1150 | else | |
1151 | level = min(level, ops->max_level); | |
1152 | ||
1153 | return level; | |
1154 | } | |
1155 | ||
261507a0 | 1156 | /* |
38c31464 DS |
1157 | * Given an address space and start and length, compress the bytes into @pages |
1158 | * that are allocated on demand. | |
261507a0 | 1159 | * |
f51d2b59 DS |
1160 | * @type_level is encoded algorithm and level, where level 0 means whatever |
1161 | * default the algorithm chooses and is opaque here; | |
1162 | * - compression algo are 0-3 | |
1163 | * - the level are bits 4-7 | |
1164 | * | |
4d3a800e DS |
1165 | * @out_pages is an in/out parameter, holds maximum number of pages to allocate |
1166 | * and returns number of actually allocated pages | |
261507a0 | 1167 | * |
38c31464 DS |
1168 | * @total_in is used to return the number of bytes actually read. It |
1169 | * may be smaller than the input length if we had to exit early because we | |
261507a0 LZ |
1170 | * ran out of room in the pages array or because we cross the |
1171 | * max_out threshold. | |
1172 | * | |
38c31464 DS |
1173 | * @total_out is an in/out parameter, must be set to the input length and will |
1174 | * be also used to return the total number of compressed bytes | |
261507a0 | 1175 | * |
38c31464 | 1176 | * @max_out tells us the max number of bytes that we're allowed to |
261507a0 LZ |
1177 | * stuff into pages |
1178 | */ | |
f51d2b59 | 1179 | int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, |
38c31464 | 1180 | u64 start, struct page **pages, |
261507a0 LZ |
1181 | unsigned long *out_pages, |
1182 | unsigned long *total_in, | |
e5d74902 | 1183 | unsigned long *total_out) |
261507a0 | 1184 | { |
1972708a | 1185 | int type = btrfs_compress_type(type_level); |
7bf49943 | 1186 | int level = btrfs_compress_level(type_level); |
261507a0 LZ |
1187 | struct list_head *workspace; |
1188 | int ret; | |
1189 | ||
b0c1fe1e | 1190 | level = btrfs_compress_set_level(type, level); |
7bf49943 | 1191 | workspace = get_workspace(type, level); |
1e4eb746 DS |
1192 | ret = compression_compress_pages(type, workspace, mapping, start, pages, |
1193 | out_pages, total_in, total_out); | |
929f4baf | 1194 | put_workspace(type, workspace); |
261507a0 LZ |
1195 | return ret; |
1196 | } | |
1197 | ||
1198 | /* | |
1199 | * pages_in is an array of pages with compressed data. | |
1200 | * | |
1201 | * disk_start is the starting logical offset of this array in the file | |
1202 | * | |
974b1adc | 1203 | * orig_bio contains the pages from the file that we want to decompress into |
261507a0 LZ |
1204 | * |
1205 | * srclen is the number of bytes in pages_in | |
1206 | * | |
1207 | * The basic idea is that we have a bio that was created by readpages. | |
1208 | * The pages in the bio are for the uncompressed data, and they may not | |
1209 | * be contiguous. They all correspond to the range of bytes covered by | |
1210 | * the compressed extent. | |
1211 | */ | |
8140dc30 | 1212 | static int btrfs_decompress_bio(struct compressed_bio *cb) |
261507a0 LZ |
1213 | { |
1214 | struct list_head *workspace; | |
1215 | int ret; | |
8140dc30 | 1216 | int type = cb->compress_type; |
261507a0 | 1217 | |
7bf49943 | 1218 | workspace = get_workspace(type, 0); |
1e4eb746 | 1219 | ret = compression_decompress_bio(type, workspace, cb); |
929f4baf | 1220 | put_workspace(type, workspace); |
e1ddce71 | 1221 | |
261507a0 LZ |
1222 | return ret; |
1223 | } | |
1224 | ||
1225 | /* | |
1226 | * a less complex decompression routine. Our compressed data fits in a | |
1227 | * single page, and we want to read a single page out of it. | |
1228 | * start_byte tells us the offset into the compressed data we're interested in | |
1229 | */ | |
1230 | int btrfs_decompress(int type, unsigned char *data_in, struct page *dest_page, | |
1231 | unsigned long start_byte, size_t srclen, size_t destlen) | |
1232 | { | |
1233 | struct list_head *workspace; | |
1234 | int ret; | |
1235 | ||
7bf49943 | 1236 | workspace = get_workspace(type, 0); |
1e4eb746 DS |
1237 | ret = compression_decompress(type, workspace, data_in, dest_page, |
1238 | start_byte, srclen, destlen); | |
929f4baf | 1239 | put_workspace(type, workspace); |
7bf49943 | 1240 | |
261507a0 LZ |
1241 | return ret; |
1242 | } | |
1243 | ||
1666edab DZ |
1244 | void __init btrfs_init_compress(void) |
1245 | { | |
d5517033 DS |
1246 | btrfs_init_workspace_manager(BTRFS_COMPRESS_NONE); |
1247 | btrfs_init_workspace_manager(BTRFS_COMPRESS_ZLIB); | |
1248 | btrfs_init_workspace_manager(BTRFS_COMPRESS_LZO); | |
1249 | zstd_init_workspace_manager(); | |
1666edab DZ |
1250 | } |
1251 | ||
e67c718b | 1252 | void __cold btrfs_exit_compress(void) |
261507a0 | 1253 | { |
2510307e DS |
1254 | btrfs_cleanup_workspace_manager(BTRFS_COMPRESS_NONE); |
1255 | btrfs_cleanup_workspace_manager(BTRFS_COMPRESS_ZLIB); | |
1256 | btrfs_cleanup_workspace_manager(BTRFS_COMPRESS_LZO); | |
1257 | zstd_cleanup_workspace_manager(); | |
261507a0 | 1258 | } |
3a39c18d LZ |
1259 | |
1260 | /* | |
1261 | * Copy uncompressed data from working buffer to pages. | |
1262 | * | |
1263 | * buf_start is the byte offset we're of the start of our workspace buffer. | |
1264 | * | |
1265 | * total_out is the last byte of the buffer | |
1266 | */ | |
14a3357b | 1267 | int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, |
3a39c18d | 1268 | unsigned long total_out, u64 disk_start, |
974b1adc | 1269 | struct bio *bio) |
3a39c18d LZ |
1270 | { |
1271 | unsigned long buf_offset; | |
1272 | unsigned long current_buf_start; | |
1273 | unsigned long start_byte; | |
6e78b3f7 | 1274 | unsigned long prev_start_byte; |
3a39c18d LZ |
1275 | unsigned long working_bytes = total_out - buf_start; |
1276 | unsigned long bytes; | |
1277 | char *kaddr; | |
974b1adc | 1278 | struct bio_vec bvec = bio_iter_iovec(bio, bio->bi_iter); |
3a39c18d LZ |
1279 | |
1280 | /* | |
1281 | * start byte is the first byte of the page we're currently | |
1282 | * copying into relative to the start of the compressed data. | |
1283 | */ | |
974b1adc | 1284 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d LZ |
1285 | |
1286 | /* we haven't yet hit data corresponding to this page */ | |
1287 | if (total_out <= start_byte) | |
1288 | return 1; | |
1289 | ||
1290 | /* | |
1291 | * the start of the data we care about is offset into | |
1292 | * the middle of our working buffer | |
1293 | */ | |
1294 | if (total_out > start_byte && buf_start < start_byte) { | |
1295 | buf_offset = start_byte - buf_start; | |
1296 | working_bytes -= buf_offset; | |
1297 | } else { | |
1298 | buf_offset = 0; | |
1299 | } | |
1300 | current_buf_start = buf_start; | |
1301 | ||
1302 | /* copy bytes from the working buffer into the pages */ | |
1303 | while (working_bytes > 0) { | |
974b1adc | 1304 | bytes = min_t(unsigned long, bvec.bv_len, |
3fd396af | 1305 | PAGE_SIZE - (buf_offset % PAGE_SIZE)); |
3a39c18d | 1306 | bytes = min(bytes, working_bytes); |
974b1adc CH |
1307 | |
1308 | kaddr = kmap_atomic(bvec.bv_page); | |
1309 | memcpy(kaddr + bvec.bv_offset, buf + buf_offset, bytes); | |
7ac687d9 | 1310 | kunmap_atomic(kaddr); |
974b1adc | 1311 | flush_dcache_page(bvec.bv_page); |
3a39c18d | 1312 | |
3a39c18d LZ |
1313 | buf_offset += bytes; |
1314 | working_bytes -= bytes; | |
1315 | current_buf_start += bytes; | |
1316 | ||
1317 | /* check if we need to pick another page */ | |
974b1adc CH |
1318 | bio_advance(bio, bytes); |
1319 | if (!bio->bi_iter.bi_size) | |
1320 | return 0; | |
1321 | bvec = bio_iter_iovec(bio, bio->bi_iter); | |
6e78b3f7 | 1322 | prev_start_byte = start_byte; |
974b1adc | 1323 | start_byte = page_offset(bvec.bv_page) - disk_start; |
3a39c18d | 1324 | |
974b1adc | 1325 | /* |
6e78b3f7 OS |
1326 | * We need to make sure we're only adjusting |
1327 | * our offset into compression working buffer when | |
1328 | * we're switching pages. Otherwise we can incorrectly | |
1329 | * keep copying when we were actually done. | |
974b1adc | 1330 | */ |
6e78b3f7 OS |
1331 | if (start_byte != prev_start_byte) { |
1332 | /* | |
1333 | * make sure our new page is covered by this | |
1334 | * working buffer | |
1335 | */ | |
1336 | if (total_out <= start_byte) | |
1337 | return 1; | |
3a39c18d | 1338 | |
6e78b3f7 OS |
1339 | /* |
1340 | * the next page in the biovec might not be adjacent | |
1341 | * to the last page, but it might still be found | |
1342 | * inside this working buffer. bump our offset pointer | |
1343 | */ | |
1344 | if (total_out > start_byte && | |
1345 | current_buf_start < start_byte) { | |
1346 | buf_offset = start_byte - buf_start; | |
1347 | working_bytes = total_out - start_byte; | |
1348 | current_buf_start = buf_start + buf_offset; | |
1349 | } | |
3a39c18d LZ |
1350 | } |
1351 | } | |
1352 | ||
1353 | return 1; | |
1354 | } | |
c2fcdcdf | 1355 | |
19562430 TT |
1356 | /* |
1357 | * Shannon Entropy calculation | |
1358 | * | |
52042d8e | 1359 | * Pure byte distribution analysis fails to determine compressibility of data. |
19562430 TT |
1360 | * Try calculating entropy to estimate the average minimum number of bits |
1361 | * needed to encode the sampled data. | |
1362 | * | |
1363 | * For convenience, return the percentage of needed bits, instead of amount of | |
1364 | * bits directly. | |
1365 | * | |
1366 | * @ENTROPY_LVL_ACEPTABLE - below that threshold, sample has low byte entropy | |
1367 | * and can be compressible with high probability | |
1368 | * | |
1369 | * @ENTROPY_LVL_HIGH - data are not compressible with high probability | |
1370 | * | |
1371 | * Use of ilog2() decreases precision, we lower the LVL to 5 to compensate. | |
1372 | */ | |
1373 | #define ENTROPY_LVL_ACEPTABLE (65) | |
1374 | #define ENTROPY_LVL_HIGH (80) | |
1375 | ||
1376 | /* | |
1377 | * For increasead precision in shannon_entropy calculation, | |
1378 | * let's do pow(n, M) to save more digits after comma: | |
1379 | * | |
1380 | * - maximum int bit length is 64 | |
1381 | * - ilog2(MAX_SAMPLE_SIZE) -> 13 | |
1382 | * - 13 * 4 = 52 < 64 -> M = 4 | |
1383 | * | |
1384 | * So use pow(n, 4). | |
1385 | */ | |
1386 | static inline u32 ilog2_w(u64 n) | |
1387 | { | |
1388 | return ilog2(n * n * n * n); | |
1389 | } | |
1390 | ||
1391 | static u32 shannon_entropy(struct heuristic_ws *ws) | |
1392 | { | |
1393 | const u32 entropy_max = 8 * ilog2_w(2); | |
1394 | u32 entropy_sum = 0; | |
1395 | u32 p, p_base, sz_base; | |
1396 | u32 i; | |
1397 | ||
1398 | sz_base = ilog2_w(ws->sample_size); | |
1399 | for (i = 0; i < BUCKET_SIZE && ws->bucket[i].count > 0; i++) { | |
1400 | p = ws->bucket[i].count; | |
1401 | p_base = ilog2_w(p); | |
1402 | entropy_sum += p * (sz_base - p_base); | |
1403 | } | |
1404 | ||
1405 | entropy_sum /= ws->sample_size; | |
1406 | return entropy_sum * 100 / entropy_max; | |
1407 | } | |
1408 | ||
440c840c TT |
1409 | #define RADIX_BASE 4U |
1410 | #define COUNTERS_SIZE (1U << RADIX_BASE) | |
1411 | ||
1412 | static u8 get4bits(u64 num, int shift) { | |
1413 | u8 low4bits; | |
1414 | ||
1415 | num >>= shift; | |
1416 | /* Reverse order */ | |
1417 | low4bits = (COUNTERS_SIZE - 1) - (num % COUNTERS_SIZE); | |
1418 | return low4bits; | |
1419 | } | |
1420 | ||
440c840c TT |
1421 | /* |
1422 | * Use 4 bits as radix base | |
52042d8e | 1423 | * Use 16 u32 counters for calculating new position in buf array |
440c840c TT |
1424 | * |
1425 | * @array - array that will be sorted | |
1426 | * @array_buf - buffer array to store sorting results | |
1427 | * must be equal in size to @array | |
1428 | * @num - array size | |
440c840c | 1429 | */ |
23ae8c63 | 1430 | static void radix_sort(struct bucket_item *array, struct bucket_item *array_buf, |
36243c91 | 1431 | int num) |
858177d3 | 1432 | { |
440c840c TT |
1433 | u64 max_num; |
1434 | u64 buf_num; | |
1435 | u32 counters[COUNTERS_SIZE]; | |
1436 | u32 new_addr; | |
1437 | u32 addr; | |
1438 | int bitlen; | |
1439 | int shift; | |
1440 | int i; | |
858177d3 | 1441 | |
440c840c TT |
1442 | /* |
1443 | * Try avoid useless loop iterations for small numbers stored in big | |
1444 | * counters. Example: 48 33 4 ... in 64bit array | |
1445 | */ | |
23ae8c63 | 1446 | max_num = array[0].count; |
440c840c | 1447 | for (i = 1; i < num; i++) { |
23ae8c63 | 1448 | buf_num = array[i].count; |
440c840c TT |
1449 | if (buf_num > max_num) |
1450 | max_num = buf_num; | |
1451 | } | |
1452 | ||
1453 | buf_num = ilog2(max_num); | |
1454 | bitlen = ALIGN(buf_num, RADIX_BASE * 2); | |
1455 | ||
1456 | shift = 0; | |
1457 | while (shift < bitlen) { | |
1458 | memset(counters, 0, sizeof(counters)); | |
1459 | ||
1460 | for (i = 0; i < num; i++) { | |
23ae8c63 | 1461 | buf_num = array[i].count; |
440c840c TT |
1462 | addr = get4bits(buf_num, shift); |
1463 | counters[addr]++; | |
1464 | } | |
1465 | ||
1466 | for (i = 1; i < COUNTERS_SIZE; i++) | |
1467 | counters[i] += counters[i - 1]; | |
1468 | ||
1469 | for (i = num - 1; i >= 0; i--) { | |
23ae8c63 | 1470 | buf_num = array[i].count; |
440c840c TT |
1471 | addr = get4bits(buf_num, shift); |
1472 | counters[addr]--; | |
1473 | new_addr = counters[addr]; | |
7add17be | 1474 | array_buf[new_addr] = array[i]; |
440c840c TT |
1475 | } |
1476 | ||
1477 | shift += RADIX_BASE; | |
1478 | ||
1479 | /* | |
1480 | * Normal radix expects to move data from a temporary array, to | |
1481 | * the main one. But that requires some CPU time. Avoid that | |
1482 | * by doing another sort iteration to original array instead of | |
1483 | * memcpy() | |
1484 | */ | |
1485 | memset(counters, 0, sizeof(counters)); | |
1486 | ||
1487 | for (i = 0; i < num; i ++) { | |
23ae8c63 | 1488 | buf_num = array_buf[i].count; |
440c840c TT |
1489 | addr = get4bits(buf_num, shift); |
1490 | counters[addr]++; | |
1491 | } | |
1492 | ||
1493 | for (i = 1; i < COUNTERS_SIZE; i++) | |
1494 | counters[i] += counters[i - 1]; | |
1495 | ||
1496 | for (i = num - 1; i >= 0; i--) { | |
23ae8c63 | 1497 | buf_num = array_buf[i].count; |
440c840c TT |
1498 | addr = get4bits(buf_num, shift); |
1499 | counters[addr]--; | |
1500 | new_addr = counters[addr]; | |
7add17be | 1501 | array[new_addr] = array_buf[i]; |
440c840c TT |
1502 | } |
1503 | ||
1504 | shift += RADIX_BASE; | |
1505 | } | |
858177d3 TT |
1506 | } |
1507 | ||
1508 | /* | |
1509 | * Size of the core byte set - how many bytes cover 90% of the sample | |
1510 | * | |
1511 | * There are several types of structured binary data that use nearly all byte | |
1512 | * values. The distribution can be uniform and counts in all buckets will be | |
1513 | * nearly the same (eg. encrypted data). Unlikely to be compressible. | |
1514 | * | |
1515 | * Other possibility is normal (Gaussian) distribution, where the data could | |
1516 | * be potentially compressible, but we have to take a few more steps to decide | |
1517 | * how much. | |
1518 | * | |
1519 | * @BYTE_CORE_SET_LOW - main part of byte values repeated frequently, | |
1520 | * compression algo can easy fix that | |
1521 | * @BYTE_CORE_SET_HIGH - data have uniform distribution and with high | |
1522 | * probability is not compressible | |
1523 | */ | |
1524 | #define BYTE_CORE_SET_LOW (64) | |
1525 | #define BYTE_CORE_SET_HIGH (200) | |
1526 | ||
1527 | static int byte_core_set_size(struct heuristic_ws *ws) | |
1528 | { | |
1529 | u32 i; | |
1530 | u32 coreset_sum = 0; | |
1531 | const u32 core_set_threshold = ws->sample_size * 90 / 100; | |
1532 | struct bucket_item *bucket = ws->bucket; | |
1533 | ||
1534 | /* Sort in reverse order */ | |
36243c91 | 1535 | radix_sort(ws->bucket, ws->bucket_b, BUCKET_SIZE); |
858177d3 TT |
1536 | |
1537 | for (i = 0; i < BYTE_CORE_SET_LOW; i++) | |
1538 | coreset_sum += bucket[i].count; | |
1539 | ||
1540 | if (coreset_sum > core_set_threshold) | |
1541 | return i; | |
1542 | ||
1543 | for (; i < BYTE_CORE_SET_HIGH && bucket[i].count > 0; i++) { | |
1544 | coreset_sum += bucket[i].count; | |
1545 | if (coreset_sum > core_set_threshold) | |
1546 | break; | |
1547 | } | |
1548 | ||
1549 | return i; | |
1550 | } | |
1551 | ||
a288e92c TT |
1552 | /* |
1553 | * Count byte values in buckets. | |
1554 | * This heuristic can detect textual data (configs, xml, json, html, etc). | |
1555 | * Because in most text-like data byte set is restricted to limited number of | |
1556 | * possible characters, and that restriction in most cases makes data easy to | |
1557 | * compress. | |
1558 | * | |
1559 | * @BYTE_SET_THRESHOLD - consider all data within this byte set size: | |
1560 | * less - compressible | |
1561 | * more - need additional analysis | |
1562 | */ | |
1563 | #define BYTE_SET_THRESHOLD (64) | |
1564 | ||
1565 | static u32 byte_set_size(const struct heuristic_ws *ws) | |
1566 | { | |
1567 | u32 i; | |
1568 | u32 byte_set_size = 0; | |
1569 | ||
1570 | for (i = 0; i < BYTE_SET_THRESHOLD; i++) { | |
1571 | if (ws->bucket[i].count > 0) | |
1572 | byte_set_size++; | |
1573 | } | |
1574 | ||
1575 | /* | |
1576 | * Continue collecting count of byte values in buckets. If the byte | |
1577 | * set size is bigger then the threshold, it's pointless to continue, | |
1578 | * the detection technique would fail for this type of data. | |
1579 | */ | |
1580 | for (; i < BUCKET_SIZE; i++) { | |
1581 | if (ws->bucket[i].count > 0) { | |
1582 | byte_set_size++; | |
1583 | if (byte_set_size > BYTE_SET_THRESHOLD) | |
1584 | return byte_set_size; | |
1585 | } | |
1586 | } | |
1587 | ||
1588 | return byte_set_size; | |
1589 | } | |
1590 | ||
1fe4f6fa TT |
1591 | static bool sample_repeated_patterns(struct heuristic_ws *ws) |
1592 | { | |
1593 | const u32 half_of_sample = ws->sample_size / 2; | |
1594 | const u8 *data = ws->sample; | |
1595 | ||
1596 | return memcmp(&data[0], &data[half_of_sample], half_of_sample) == 0; | |
1597 | } | |
1598 | ||
a440d48c TT |
1599 | static void heuristic_collect_sample(struct inode *inode, u64 start, u64 end, |
1600 | struct heuristic_ws *ws) | |
1601 | { | |
1602 | struct page *page; | |
1603 | u64 index, index_end; | |
1604 | u32 i, curr_sample_pos; | |
1605 | u8 *in_data; | |
1606 | ||
1607 | /* | |
1608 | * Compression handles the input data by chunks of 128KiB | |
1609 | * (defined by BTRFS_MAX_UNCOMPRESSED) | |
1610 | * | |
1611 | * We do the same for the heuristic and loop over the whole range. | |
1612 | * | |
1613 | * MAX_SAMPLE_SIZE - calculated under assumption that heuristic will | |
1614 | * process no more than BTRFS_MAX_UNCOMPRESSED at a time. | |
1615 | */ | |
1616 | if (end - start > BTRFS_MAX_UNCOMPRESSED) | |
1617 | end = start + BTRFS_MAX_UNCOMPRESSED; | |
1618 | ||
1619 | index = start >> PAGE_SHIFT; | |
1620 | index_end = end >> PAGE_SHIFT; | |
1621 | ||
1622 | /* Don't miss unaligned end */ | |
1623 | if (!IS_ALIGNED(end, PAGE_SIZE)) | |
1624 | index_end++; | |
1625 | ||
1626 | curr_sample_pos = 0; | |
1627 | while (index < index_end) { | |
1628 | page = find_get_page(inode->i_mapping, index); | |
1629 | in_data = kmap(page); | |
1630 | /* Handle case where the start is not aligned to PAGE_SIZE */ | |
1631 | i = start % PAGE_SIZE; | |
1632 | while (i < PAGE_SIZE - SAMPLING_READ_SIZE) { | |
1633 | /* Don't sample any garbage from the last page */ | |
1634 | if (start > end - SAMPLING_READ_SIZE) | |
1635 | break; | |
1636 | memcpy(&ws->sample[curr_sample_pos], &in_data[i], | |
1637 | SAMPLING_READ_SIZE); | |
1638 | i += SAMPLING_INTERVAL; | |
1639 | start += SAMPLING_INTERVAL; | |
1640 | curr_sample_pos += SAMPLING_READ_SIZE; | |
1641 | } | |
1642 | kunmap(page); | |
1643 | put_page(page); | |
1644 | ||
1645 | index++; | |
1646 | } | |
1647 | ||
1648 | ws->sample_size = curr_sample_pos; | |
1649 | } | |
1650 | ||
c2fcdcdf TT |
1651 | /* |
1652 | * Compression heuristic. | |
1653 | * | |
1654 | * For now is's a naive and optimistic 'return true', we'll extend the logic to | |
1655 | * quickly (compared to direct compression) detect data characteristics | |
1656 | * (compressible/uncompressible) to avoid wasting CPU time on uncompressible | |
1657 | * data. | |
1658 | * | |
1659 | * The following types of analysis can be performed: | |
1660 | * - detect mostly zero data | |
1661 | * - detect data with low "byte set" size (text, etc) | |
1662 | * - detect data with low/high "core byte" set | |
1663 | * | |
1664 | * Return non-zero if the compression should be done, 0 otherwise. | |
1665 | */ | |
1666 | int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) | |
1667 | { | |
7bf49943 | 1668 | struct list_head *ws_list = get_workspace(0, 0); |
4e439a0b | 1669 | struct heuristic_ws *ws; |
a440d48c TT |
1670 | u32 i; |
1671 | u8 byte; | |
19562430 | 1672 | int ret = 0; |
c2fcdcdf | 1673 | |
4e439a0b TT |
1674 | ws = list_entry(ws_list, struct heuristic_ws, list); |
1675 | ||
a440d48c TT |
1676 | heuristic_collect_sample(inode, start, end, ws); |
1677 | ||
1fe4f6fa TT |
1678 | if (sample_repeated_patterns(ws)) { |
1679 | ret = 1; | |
1680 | goto out; | |
1681 | } | |
1682 | ||
a440d48c TT |
1683 | memset(ws->bucket, 0, sizeof(*ws->bucket)*BUCKET_SIZE); |
1684 | ||
1685 | for (i = 0; i < ws->sample_size; i++) { | |
1686 | byte = ws->sample[i]; | |
1687 | ws->bucket[byte].count++; | |
c2fcdcdf TT |
1688 | } |
1689 | ||
a288e92c TT |
1690 | i = byte_set_size(ws); |
1691 | if (i < BYTE_SET_THRESHOLD) { | |
1692 | ret = 2; | |
1693 | goto out; | |
1694 | } | |
1695 | ||
858177d3 TT |
1696 | i = byte_core_set_size(ws); |
1697 | if (i <= BYTE_CORE_SET_LOW) { | |
1698 | ret = 3; | |
1699 | goto out; | |
1700 | } | |
1701 | ||
1702 | if (i >= BYTE_CORE_SET_HIGH) { | |
1703 | ret = 0; | |
1704 | goto out; | |
1705 | } | |
1706 | ||
19562430 TT |
1707 | i = shannon_entropy(ws); |
1708 | if (i <= ENTROPY_LVL_ACEPTABLE) { | |
1709 | ret = 4; | |
1710 | goto out; | |
1711 | } | |
1712 | ||
1713 | /* | |
1714 | * For the levels below ENTROPY_LVL_HIGH, additional analysis would be | |
1715 | * needed to give green light to compression. | |
1716 | * | |
1717 | * For now just assume that compression at that level is not worth the | |
1718 | * resources because: | |
1719 | * | |
1720 | * 1. it is possible to defrag the data later | |
1721 | * | |
1722 | * 2. the data would turn out to be hardly compressible, eg. 150 byte | |
1723 | * values, every bucket has counter at level ~54. The heuristic would | |
1724 | * be confused. This can happen when data have some internal repeated | |
1725 | * patterns like "abbacbbc...". This can be detected by analyzing | |
1726 | * pairs of bytes, which is too costly. | |
1727 | */ | |
1728 | if (i < ENTROPY_LVL_HIGH) { | |
1729 | ret = 5; | |
1730 | goto out; | |
1731 | } else { | |
1732 | ret = 0; | |
1733 | goto out; | |
1734 | } | |
1735 | ||
1fe4f6fa | 1736 | out: |
929f4baf | 1737 | put_workspace(0, ws_list); |
c2fcdcdf TT |
1738 | return ret; |
1739 | } | |
f51d2b59 | 1740 | |
d0ab62ce DZ |
1741 | /* |
1742 | * Convert the compression suffix (eg. after "zlib" starting with ":") to | |
1743 | * level, unrecognized string will set the default level | |
1744 | */ | |
1745 | unsigned int btrfs_compress_str2level(unsigned int type, const char *str) | |
f51d2b59 | 1746 | { |
d0ab62ce DZ |
1747 | unsigned int level = 0; |
1748 | int ret; | |
1749 | ||
1750 | if (!type) | |
f51d2b59 DS |
1751 | return 0; |
1752 | ||
d0ab62ce DZ |
1753 | if (str[0] == ':') { |
1754 | ret = kstrtouint(str + 1, 10, &level); | |
1755 | if (ret) | |
1756 | level = 0; | |
1757 | } | |
1758 | ||
b0c1fe1e DS |
1759 | level = btrfs_compress_set_level(type, level); |
1760 | ||
1761 | return level; | |
1762 | } |