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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> | |
a75b81c3 | 11 | #include <linux/pagevec.h> |
c8b97818 | 12 | #include <linux/highmem.h> |
e41d12f5 | 13 | #include <linux/kthread.h> |
c8b97818 CM |
14 | #include <linux/time.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/string.h> | |
c8b97818 | 17 | #include <linux/backing-dev.h> |
c8b97818 | 18 | #include <linux/writeback.h> |
4088a47e | 19 | #include <linux/psi.h> |
5a0e3ad6 | 20 | #include <linux/slab.h> |
fe308533 | 21 | #include <linux/sched/mm.h> |
19562430 | 22 | #include <linux/log2.h> |
d5178578 | 23 | #include <crypto/hash.h> |
602cbe91 | 24 | #include "misc.h" |
c8b97818 | 25 | #include "ctree.h" |
ec8eb376 | 26 | #include "fs.h" |
c8b97818 CM |
27 | #include "disk-io.h" |
28 | #include "transaction.h" | |
29 | #include "btrfs_inode.h" | |
103c1972 | 30 | #include "bio.h" |
c8b97818 | 31 | #include "ordered-data.h" |
c8b97818 CM |
32 | #include "compression.h" |
33 | #include "extent_io.h" | |
34 | #include "extent_map.h" | |
6a404910 | 35 | #include "subpage.h" |
764c7c9a | 36 | #include "zoned.h" |
7c8ede16 | 37 | #include "file-item.h" |
7f0add25 | 38 | #include "super.h" |
c8b97818 | 39 | |
544fe4a9 CH |
40 | struct bio_set btrfs_compressed_bioset; |
41 | ||
e128f9c3 DS |
42 | static const char* const btrfs_compress_types[] = { "", "zlib", "lzo", "zstd" }; |
43 | ||
44 | const char* btrfs_compress_type2str(enum btrfs_compression_type type) | |
45 | { | |
46 | switch (type) { | |
47 | case BTRFS_COMPRESS_ZLIB: | |
48 | case BTRFS_COMPRESS_LZO: | |
49 | case BTRFS_COMPRESS_ZSTD: | |
50 | case BTRFS_COMPRESS_NONE: | |
51 | return btrfs_compress_types[type]; | |
ce96b7ff CX |
52 | default: |
53 | break; | |
e128f9c3 DS |
54 | } |
55 | ||
56 | return NULL; | |
57 | } | |
58 | ||
544fe4a9 CH |
59 | static inline struct compressed_bio *to_compressed_bio(struct btrfs_bio *bbio) |
60 | { | |
61 | return container_of(bbio, struct compressed_bio, bbio); | |
62 | } | |
63 | ||
64 | static struct compressed_bio *alloc_compressed_bio(struct btrfs_inode *inode, | |
65 | u64 start, blk_opf_t op, | |
66 | btrfs_bio_end_io_t end_io) | |
67 | { | |
68 | struct btrfs_bio *bbio; | |
69 | ||
70 | bbio = btrfs_bio(bio_alloc_bioset(NULL, BTRFS_MAX_COMPRESSED_PAGES, op, | |
71 | GFP_NOFS, &btrfs_compressed_bioset)); | |
72 | btrfs_bio_init(bbio, inode, end_io, NULL); | |
73 | bbio->file_offset = start; | |
74 | return to_compressed_bio(bbio); | |
75 | } | |
76 | ||
aa53e3bf JT |
77 | bool btrfs_compress_is_valid_type(const char *str, size_t len) |
78 | { | |
79 | int i; | |
80 | ||
81 | for (i = 1; i < ARRAY_SIZE(btrfs_compress_types); i++) { | |
82 | size_t comp_len = strlen(btrfs_compress_types[i]); | |
83 | ||
84 | if (len < comp_len) | |
85 | continue; | |
86 | ||
87 | if (!strncmp(btrfs_compress_types[i], str, comp_len)) | |
88 | return true; | |
89 | } | |
90 | return false; | |
91 | } | |
92 | ||
1e4eb746 DS |
93 | static int compression_compress_pages(int type, struct list_head *ws, |
94 | struct address_space *mapping, u64 start, struct page **pages, | |
95 | unsigned long *out_pages, unsigned long *total_in, | |
96 | unsigned long *total_out) | |
97 | { | |
98 | switch (type) { | |
99 | case BTRFS_COMPRESS_ZLIB: | |
100 | return zlib_compress_pages(ws, mapping, start, pages, | |
101 | out_pages, total_in, total_out); | |
102 | case BTRFS_COMPRESS_LZO: | |
103 | return lzo_compress_pages(ws, mapping, start, pages, | |
104 | out_pages, total_in, total_out); | |
105 | case BTRFS_COMPRESS_ZSTD: | |
106 | return zstd_compress_pages(ws, mapping, start, pages, | |
107 | out_pages, total_in, total_out); | |
108 | case BTRFS_COMPRESS_NONE: | |
109 | default: | |
110 | /* | |
1d8ba9e7 QW |
111 | * This can happen when compression races with remount setting |
112 | * it to 'no compress', while caller doesn't call | |
113 | * inode_need_compress() to check if we really need to | |
114 | * compress. | |
115 | * | |
116 | * Not a big deal, just need to inform caller that we | |
117 | * haven't allocated any pages yet. | |
1e4eb746 | 118 | */ |
1d8ba9e7 | 119 | *out_pages = 0; |
1e4eb746 DS |
120 | return -E2BIG; |
121 | } | |
122 | } | |
123 | ||
4a9e803e SY |
124 | static int compression_decompress_bio(struct list_head *ws, |
125 | struct compressed_bio *cb) | |
1e4eb746 | 126 | { |
4a9e803e | 127 | switch (cb->compress_type) { |
1e4eb746 DS |
128 | case BTRFS_COMPRESS_ZLIB: return zlib_decompress_bio(ws, cb); |
129 | case BTRFS_COMPRESS_LZO: return lzo_decompress_bio(ws, cb); | |
130 | case BTRFS_COMPRESS_ZSTD: return zstd_decompress_bio(ws, cb); | |
131 | case BTRFS_COMPRESS_NONE: | |
132 | default: | |
133 | /* | |
134 | * This can't happen, the type is validated several times | |
135 | * before we get here. | |
136 | */ | |
137 | BUG(); | |
138 | } | |
139 | } | |
140 | ||
141 | static int compression_decompress(int type, struct list_head *ws, | |
3e09b5b2 | 142 | const u8 *data_in, struct page *dest_page, |
1e4eb746 DS |
143 | unsigned long start_byte, size_t srclen, size_t destlen) |
144 | { | |
145 | switch (type) { | |
146 | case BTRFS_COMPRESS_ZLIB: return zlib_decompress(ws, data_in, dest_page, | |
147 | start_byte, srclen, destlen); | |
148 | case BTRFS_COMPRESS_LZO: return lzo_decompress(ws, data_in, dest_page, | |
149 | start_byte, srclen, destlen); | |
150 | case BTRFS_COMPRESS_ZSTD: return zstd_decompress(ws, data_in, dest_page, | |
151 | start_byte, srclen, destlen); | |
152 | case BTRFS_COMPRESS_NONE: | |
153 | default: | |
154 | /* | |
155 | * This can't happen, the type is validated several times | |
156 | * before we get here. | |
157 | */ | |
158 | BUG(); | |
159 | } | |
160 | } | |
161 | ||
32586c5b CH |
162 | static void btrfs_free_compressed_pages(struct compressed_bio *cb) |
163 | { | |
164 | for (unsigned int i = 0; i < cb->nr_pages; i++) { | |
165 | struct page *page = cb->compressed_pages[i]; | |
166 | ||
167 | page->mapping = NULL; | |
168 | put_page(page); | |
169 | } | |
170 | kfree(cb->compressed_pages); | |
171 | } | |
172 | ||
8140dc30 | 173 | static int btrfs_decompress_bio(struct compressed_bio *cb); |
48a3b636 | 174 | |
30493ff4 | 175 | static void end_compressed_bio_read(struct btrfs_bio *bbio) |
86ccbb4d | 176 | { |
544fe4a9 CH |
177 | struct compressed_bio *cb = to_compressed_bio(bbio); |
178 | blk_status_t status = bbio->bio.bi_status; | |
86ccbb4d | 179 | |
544fe4a9 CH |
180 | if (!status) |
181 | status = errno_to_blk_status(btrfs_decompress_bio(cb)); | |
81bd9328 | 182 | |
32586c5b | 183 | btrfs_free_compressed_pages(cb); |
544fe4a9 | 184 | btrfs_bio_end_io(btrfs_bio(cb->orig_bio), status); |
917f32a2 | 185 | bio_put(&bbio->bio); |
c8b97818 CM |
186 | } |
187 | ||
188 | /* | |
189 | * Clear the writeback bits on all of the file | |
190 | * pages for a compressed write | |
191 | */ | |
544fe4a9 | 192 | static noinline void end_compressed_writeback(const struct compressed_bio *cb) |
c8b97818 | 193 | { |
544fe4a9 | 194 | struct inode *inode = &cb->bbio.inode->vfs_inode; |
741ec653 | 195 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
09cbfeaf KS |
196 | unsigned long index = cb->start >> PAGE_SHIFT; |
197 | unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT; | |
a75b81c3 | 198 | struct folio_batch fbatch; |
544fe4a9 | 199 | const int errno = blk_status_to_errno(cb->bbio.bio.bi_status); |
c8b97818 CM |
200 | int i; |
201 | int ret; | |
202 | ||
606f82e7 JB |
203 | if (errno) |
204 | mapping_set_error(inode->i_mapping, errno); | |
7bdcefc1 | 205 | |
a75b81c3 VMO |
206 | folio_batch_init(&fbatch); |
207 | while (index <= end_index) { | |
208 | ret = filemap_get_folios(inode->i_mapping, &index, end_index, | |
209 | &fbatch); | |
210 | ||
211 | if (ret == 0) | |
212 | return; | |
213 | ||
c8b97818 | 214 | for (i = 0; i < ret; i++) { |
a75b81c3 VMO |
215 | struct folio *folio = fbatch.folios[i]; |
216 | ||
606f82e7 | 217 | if (errno) |
a75b81c3 VMO |
218 | folio_set_error(folio); |
219 | btrfs_page_clamp_clear_writeback(fs_info, &folio->page, | |
741ec653 | 220 | cb->start, cb->len); |
c8b97818 | 221 | } |
a75b81c3 | 222 | folio_batch_release(&fbatch); |
c8b97818 CM |
223 | } |
224 | /* the inode may be gone now */ | |
c8b97818 CM |
225 | } |
226 | ||
6853c64a | 227 | static void finish_compressed_bio_write(struct compressed_bio *cb) |
c8b97818 | 228 | { |
6853c64a QW |
229 | /* |
230 | * Ok, we're the last bio for this extent, step one is to call back | |
231 | * into the FS and do all the end_io operations. | |
c8b97818 | 232 | */ |
544fe4a9 | 233 | btrfs_writepage_endio_finish_ordered(cb->bbio.inode, NULL, |
c629732d | 234 | cb->start, cb->start + cb->len - 1, |
544fe4a9 | 235 | cb->bbio.bio.bi_status == BLK_STS_OK); |
c8b97818 | 236 | |
7c0c7269 | 237 | if (cb->writeback) |
544fe4a9 | 238 | end_compressed_writeback(cb); |
6853c64a | 239 | /* Note, our inode could be gone now */ |
c8b97818 | 240 | |
32586c5b | 241 | btrfs_free_compressed_pages(cb); |
544fe4a9 | 242 | bio_put(&cb->bbio.bio); |
6853c64a QW |
243 | } |
244 | ||
fed8a72d CH |
245 | static void btrfs_finish_compressed_write_work(struct work_struct *work) |
246 | { | |
247 | struct compressed_bio *cb = | |
248 | container_of(work, struct compressed_bio, write_end_work); | |
249 | ||
250 | finish_compressed_bio_write(cb); | |
251 | } | |
252 | ||
6853c64a QW |
253 | /* |
254 | * Do the cleanup once all the compressed pages hit the disk. This will clear | |
255 | * writeback on the file pages and free the compressed pages. | |
256 | * | |
257 | * This also calls the writeback end hooks for the file pages so that metadata | |
258 | * and checksums can be updated in the file. | |
259 | */ | |
917f32a2 | 260 | static void end_compressed_bio_write(struct btrfs_bio *bbio) |
6853c64a | 261 | { |
544fe4a9 CH |
262 | struct compressed_bio *cb = to_compressed_bio(bbio); |
263 | struct btrfs_fs_info *fs_info = bbio->inode->root->fs_info; | |
6853c64a | 264 | |
d5e4377d | 265 | queue_work(fs_info->compressed_write_workers, &cb->write_end_work); |
c8b97818 CM |
266 | } |
267 | ||
10e924bc CH |
268 | static void btrfs_add_compressed_bio_pages(struct compressed_bio *cb, |
269 | u64 disk_bytenr) | |
270 | { | |
271 | struct btrfs_fs_info *fs_info = cb->bbio.inode->root->fs_info; | |
272 | struct bio *bio = &cb->bbio.bio; | |
273 | u64 cur_disk_byte = disk_bytenr; | |
274 | ||
275 | bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT; | |
276 | while (cur_disk_byte < disk_bytenr + cb->compressed_len) { | |
277 | u64 offset = cur_disk_byte - disk_bytenr; | |
278 | unsigned int index = offset >> PAGE_SHIFT; | |
279 | unsigned int real_size; | |
280 | unsigned int added; | |
281 | struct page *page = cb->compressed_pages[index]; | |
282 | ||
283 | /* | |
284 | * We have various limit on the real read size: | |
285 | * - page boundary | |
286 | * - compressed length boundary | |
287 | */ | |
288 | real_size = min_t(u64, U32_MAX, PAGE_SIZE - offset_in_page(offset)); | |
289 | real_size = min_t(u64, real_size, cb->compressed_len - offset); | |
290 | ASSERT(IS_ALIGNED(real_size, fs_info->sectorsize)); | |
291 | ||
292 | added = bio_add_page(bio, page, real_size, offset_in_page(offset)); | |
293 | /* | |
294 | * Maximum compressed extent is smaller than bio size limit, | |
295 | * thus bio_add_page() should always success. | |
296 | */ | |
297 | ASSERT(added == real_size); | |
298 | cur_disk_byte += added; | |
299 | } | |
300 | ||
301 | ASSERT(bio->bi_iter.bi_size); | |
302 | } | |
303 | ||
c8b97818 CM |
304 | /* |
305 | * worker function to build and submit bios for previously compressed pages. | |
306 | * The corresponding pages in the inode should be marked for writeback | |
307 | * and the compressed pages should have a reference on them for dropping | |
308 | * when the IO is complete. | |
309 | * | |
310 | * This also checksums the file bytes and gets things ready for | |
311 | * the end io hooks. | |
312 | */ | |
544fe4a9 | 313 | void btrfs_submit_compressed_write(struct btrfs_inode *inode, u64 start, |
65b5355f AJ |
314 | unsigned int len, u64 disk_start, |
315 | unsigned int compressed_len, | |
c8b97818 | 316 | struct page **compressed_pages, |
65b5355f | 317 | unsigned int nr_pages, |
bf9486d6 | 318 | blk_opf_t write_flags, |
7c0c7269 OS |
319 | struct cgroup_subsys_state *blkcg_css, |
320 | bool writeback) | |
c8b97818 | 321 | { |
c7ee1819 | 322 | struct btrfs_fs_info *fs_info = inode->root->fs_info; |
c8b97818 | 323 | struct compressed_bio *cb; |
c8b97818 | 324 | |
bbbff01a QW |
325 | ASSERT(IS_ALIGNED(start, fs_info->sectorsize) && |
326 | IS_ALIGNED(len, fs_info->sectorsize)); | |
544fe4a9 CH |
327 | |
328 | if (blkcg_css) { | |
329 | kthread_associate_blkcg(blkcg_css); | |
330 | write_flags |= REQ_CGROUP_PUNT; | |
331 | } | |
332 | write_flags |= REQ_BTRFS_ONE_ORDERED; | |
333 | ||
334 | cb = alloc_compressed_bio(inode, start, REQ_OP_WRITE | write_flags, | |
335 | end_compressed_bio_write); | |
c8b97818 CM |
336 | cb->start = start; |
337 | cb->len = len; | |
338 | cb->compressed_pages = compressed_pages; | |
339 | cb->compressed_len = compressed_len; | |
7c0c7269 | 340 | cb->writeback = writeback; |
fed8a72d | 341 | INIT_WORK(&cb->write_end_work, btrfs_finish_compressed_write_work); |
c8b97818 CM |
342 | cb->nr_pages = nr_pages; |
343 | ||
10e924bc CH |
344 | btrfs_add_compressed_bio_pages(cb, disk_start); |
345 | btrfs_submit_bio(&cb->bbio.bio, 0); | |
d20f7043 | 346 | |
acee08aa DZ |
347 | if (blkcg_css) |
348 | kthread_associate_blkcg(NULL); | |
c8b97818 CM |
349 | } |
350 | ||
6a404910 QW |
351 | /* |
352 | * Add extra pages in the same compressed file extent so that we don't need to | |
353 | * re-read the same extent again and again. | |
354 | * | |
355 | * NOTE: this won't work well for subpage, as for subpage read, we lock the | |
356 | * full page then submit bio for each compressed/regular extents. | |
357 | * | |
358 | * This means, if we have several sectors in the same page points to the same | |
359 | * on-disk compressed data, we will re-read the same extent many times and | |
360 | * this function can only help for the next page. | |
361 | */ | |
771ed689 CM |
362 | static noinline int add_ra_bio_pages(struct inode *inode, |
363 | u64 compressed_end, | |
4088a47e | 364 | struct compressed_bio *cb, |
82e60d00 | 365 | int *memstall, unsigned long *pflags) |
771ed689 | 366 | { |
6a404910 | 367 | struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); |
771ed689 | 368 | unsigned long end_index; |
d7294e4d | 369 | u64 cur = btrfs_bio(cb->orig_bio)->file_offset + cb->orig_bio->bi_iter.bi_size; |
771ed689 CM |
370 | u64 isize = i_size_read(inode); |
371 | int ret; | |
372 | struct page *page; | |
771ed689 CM |
373 | struct extent_map *em; |
374 | struct address_space *mapping = inode->i_mapping; | |
771ed689 CM |
375 | struct extent_map_tree *em_tree; |
376 | struct extent_io_tree *tree; | |
6a404910 | 377 | int sectors_missed = 0; |
771ed689 | 378 | |
771ed689 CM |
379 | em_tree = &BTRFS_I(inode)->extent_tree; |
380 | tree = &BTRFS_I(inode)->io_tree; | |
381 | ||
382 | if (isize == 0) | |
383 | return 0; | |
384 | ||
ca62e85d QW |
385 | /* |
386 | * For current subpage support, we only support 64K page size, | |
387 | * which means maximum compressed extent size (128K) is just 2x page | |
388 | * size. | |
389 | * This makes readahead less effective, so here disable readahead for | |
390 | * subpage for now, until full compressed write is supported. | |
391 | */ | |
392 | if (btrfs_sb(inode->i_sb)->sectorsize < PAGE_SIZE) | |
393 | return 0; | |
394 | ||
09cbfeaf | 395 | end_index = (i_size_read(inode) - 1) >> PAGE_SHIFT; |
771ed689 | 396 | |
6a404910 QW |
397 | while (cur < compressed_end) { |
398 | u64 page_end; | |
399 | u64 pg_index = cur >> PAGE_SHIFT; | |
400 | u32 add_size; | |
771ed689 | 401 | |
306e16ce | 402 | if (pg_index > end_index) |
771ed689 CM |
403 | break; |
404 | ||
0a943c65 | 405 | page = xa_load(&mapping->i_pages, pg_index); |
3159f943 | 406 | if (page && !xa_is_value(page)) { |
6a404910 QW |
407 | sectors_missed += (PAGE_SIZE - offset_in_page(cur)) >> |
408 | fs_info->sectorsize_bits; | |
409 | ||
410 | /* Beyond threshold, no need to continue */ | |
411 | if (sectors_missed > 4) | |
771ed689 | 412 | break; |
6a404910 QW |
413 | |
414 | /* | |
415 | * Jump to next page start as we already have page for | |
416 | * current offset. | |
417 | */ | |
418 | cur = (pg_index << PAGE_SHIFT) + PAGE_SIZE; | |
419 | continue; | |
771ed689 CM |
420 | } |
421 | ||
c62d2555 MH |
422 | page = __page_cache_alloc(mapping_gfp_constraint(mapping, |
423 | ~__GFP_FS)); | |
771ed689 CM |
424 | if (!page) |
425 | break; | |
426 | ||
c62d2555 | 427 | if (add_to_page_cache_lru(page, mapping, pg_index, GFP_NOFS)) { |
09cbfeaf | 428 | put_page(page); |
6a404910 QW |
429 | /* There is already a page, skip to page end */ |
430 | cur = (pg_index << PAGE_SHIFT) + PAGE_SIZE; | |
431 | continue; | |
771ed689 CM |
432 | } |
433 | ||
82e60d00 | 434 | if (!*memstall && PageWorkingset(page)) { |
4088a47e | 435 | psi_memstall_enter(pflags); |
82e60d00 JW |
436 | *memstall = 1; |
437 | } | |
4088a47e | 438 | |
32443de3 QW |
439 | ret = set_page_extent_mapped(page); |
440 | if (ret < 0) { | |
441 | unlock_page(page); | |
442 | put_page(page); | |
443 | break; | |
444 | } | |
445 | ||
6a404910 | 446 | page_end = (pg_index << PAGE_SHIFT) + PAGE_SIZE - 1; |
570eb97b | 447 | lock_extent(tree, cur, page_end, NULL); |
890871be | 448 | read_lock(&em_tree->lock); |
6a404910 | 449 | em = lookup_extent_mapping(em_tree, cur, page_end + 1 - cur); |
890871be | 450 | read_unlock(&em_tree->lock); |
771ed689 | 451 | |
6a404910 QW |
452 | /* |
453 | * At this point, we have a locked page in the page cache for | |
454 | * these bytes in the file. But, we have to make sure they map | |
455 | * to this compressed extent on disk. | |
456 | */ | |
457 | if (!em || cur < em->start || | |
458 | (cur + fs_info->sectorsize > extent_map_end(em)) || | |
4f024f37 | 459 | (em->block_start >> 9) != cb->orig_bio->bi_iter.bi_sector) { |
771ed689 | 460 | free_extent_map(em); |
570eb97b | 461 | unlock_extent(tree, cur, page_end, NULL); |
771ed689 | 462 | unlock_page(page); |
09cbfeaf | 463 | put_page(page); |
771ed689 CM |
464 | break; |
465 | } | |
466 | free_extent_map(em); | |
467 | ||
468 | if (page->index == end_index) { | |
7073017a | 469 | size_t zero_offset = offset_in_page(isize); |
771ed689 CM |
470 | |
471 | if (zero_offset) { | |
472 | int zeros; | |
09cbfeaf | 473 | zeros = PAGE_SIZE - zero_offset; |
d048b9c2 | 474 | memzero_page(page, zero_offset, zeros); |
771ed689 CM |
475 | } |
476 | } | |
477 | ||
6a404910 QW |
478 | add_size = min(em->start + em->len, page_end + 1) - cur; |
479 | ret = bio_add_page(cb->orig_bio, page, add_size, offset_in_page(cur)); | |
480 | if (ret != add_size) { | |
570eb97b | 481 | unlock_extent(tree, cur, page_end, NULL); |
771ed689 | 482 | unlock_page(page); |
09cbfeaf | 483 | put_page(page); |
771ed689 CM |
484 | break; |
485 | } | |
6a404910 QW |
486 | /* |
487 | * If it's subpage, we also need to increase its | |
488 | * subpage::readers number, as at endio we will decrease | |
489 | * subpage::readers and to unlock the page. | |
490 | */ | |
491 | if (fs_info->sectorsize < PAGE_SIZE) | |
492 | btrfs_subpage_start_reader(fs_info, page, cur, add_size); | |
493 | put_page(page); | |
494 | cur += add_size; | |
771ed689 | 495 | } |
771ed689 CM |
496 | return 0; |
497 | } | |
498 | ||
c8b97818 CM |
499 | /* |
500 | * for a compressed read, the bio we get passed has all the inode pages | |
501 | * in it. We don't actually do IO on those pages but allocate new ones | |
502 | * to hold the compressed pages on disk. | |
503 | * | |
4f024f37 | 504 | * bio->bi_iter.bi_sector points to the compressed extent on disk |
c8b97818 | 505 | * bio->bi_io_vec points to all of the inode pages |
c8b97818 CM |
506 | * |
507 | * After the compressed pages are read, we copy the bytes into the | |
508 | * bio we were passed and then call the bio end_io calls | |
509 | */ | |
544fe4a9 | 510 | void btrfs_submit_compressed_read(struct bio *bio, int mirror_num) |
c8b97818 | 511 | { |
544fe4a9 CH |
512 | struct btrfs_inode *inode = btrfs_bio(bio)->inode; |
513 | struct btrfs_fs_info *fs_info = inode->root->fs_info; | |
514 | struct extent_map_tree *em_tree = &inode->extent_tree; | |
c8b97818 | 515 | struct compressed_bio *cb; |
356b4a2d | 516 | unsigned int compressed_len; |
f472c28f | 517 | const u64 disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT; |
e7aff33e | 518 | u64 file_offset = btrfs_bio(bio)->file_offset; |
e04ca626 CM |
519 | u64 em_len; |
520 | u64 em_start; | |
c8b97818 | 521 | struct extent_map *em; |
82e60d00 JW |
522 | unsigned long pflags; |
523 | int memstall = 0; | |
f9f15de8 | 524 | blk_status_t ret; |
dd137dd1 | 525 | int ret2; |
c8b97818 CM |
526 | |
527 | /* we need the actual starting offset of this extent in the file */ | |
890871be | 528 | read_lock(&em_tree->lock); |
557023ea | 529 | em = lookup_extent_mapping(em_tree, file_offset, fs_info->sectorsize); |
890871be | 530 | read_unlock(&em_tree->lock); |
f9f15de8 JB |
531 | if (!em) { |
532 | ret = BLK_STS_IOERR; | |
533 | goto out; | |
534 | } | |
c8b97818 | 535 | |
557023ea | 536 | ASSERT(em->compress_type != BTRFS_COMPRESS_NONE); |
d20f7043 | 537 | compressed_len = em->block_len; |
6b82ce8d | 538 | |
544fe4a9 CH |
539 | cb = alloc_compressed_bio(inode, file_offset, REQ_OP_READ, |
540 | end_compressed_bio_read); | |
c8b97818 | 541 | |
ff5b7ee3 | 542 | cb->start = em->orig_start; |
e04ca626 CM |
543 | em_len = em->len; |
544 | em_start = em->start; | |
d20f7043 | 545 | |
81381053 | 546 | cb->len = bio->bi_iter.bi_size; |
c8b97818 | 547 | cb->compressed_len = compressed_len; |
1d8fa2e2 | 548 | cb->compress_type = em->compress_type; |
c8b97818 CM |
549 | cb->orig_bio = bio; |
550 | ||
1d8fa2e2 | 551 | free_extent_map(em); |
1d8fa2e2 | 552 | |
dd137dd1 STD |
553 | cb->nr_pages = DIV_ROUND_UP(compressed_len, PAGE_SIZE); |
554 | cb->compressed_pages = kcalloc(cb->nr_pages, sizeof(struct page *), GFP_NOFS); | |
f9f15de8 JB |
555 | if (!cb->compressed_pages) { |
556 | ret = BLK_STS_RESOURCE; | |
544fe4a9 | 557 | goto out_free_bio; |
f9f15de8 | 558 | } |
6b82ce8d | 559 | |
dd137dd1 STD |
560 | ret2 = btrfs_alloc_page_array(cb->nr_pages, cb->compressed_pages); |
561 | if (ret2) { | |
562 | ret = BLK_STS_RESOURCE; | |
544fe4a9 | 563 | goto out_free_compressed_pages; |
c8b97818 | 564 | } |
c8b97818 | 565 | |
544fe4a9 CH |
566 | add_ra_bio_pages(&inode->vfs_inode, em_start + em_len, cb, &memstall, |
567 | &pflags); | |
771ed689 | 568 | |
771ed689 | 569 | /* include any pages we added in add_ra-bio_pages */ |
81381053 | 570 | cb->len = bio->bi_iter.bi_size; |
771ed689 | 571 | |
10e924bc | 572 | btrfs_add_compressed_bio_pages(cb, disk_bytenr); |
524bcd1e | 573 | |
82e60d00 | 574 | if (memstall) |
4088a47e CH |
575 | psi_memstall_leave(&pflags); |
576 | ||
10e924bc | 577 | btrfs_submit_bio(&cb->bbio.bio, mirror_num); |
cb4411dd | 578 | return; |
6b82ce8d | 579 | |
544fe4a9 | 580 | out_free_compressed_pages: |
6b82ce8d | 581 | kfree(cb->compressed_pages); |
544fe4a9 | 582 | out_free_bio: |
10e924bc | 583 | bio_put(&cb->bbio.bio); |
544fe4a9 | 584 | out: |
917f32a2 | 585 | btrfs_bio_end_io(btrfs_bio(bio), ret); |
c8b97818 | 586 | } |
261507a0 | 587 | |
17b5a6c1 TT |
588 | /* |
589 | * Heuristic uses systematic sampling to collect data from the input data | |
590 | * range, the logic can be tuned by the following constants: | |
591 | * | |
592 | * @SAMPLING_READ_SIZE - how many bytes will be copied from for each sample | |
593 | * @SAMPLING_INTERVAL - range from which the sampled data can be collected | |
594 | */ | |
595 | #define SAMPLING_READ_SIZE (16) | |
596 | #define SAMPLING_INTERVAL (256) | |
597 | ||
598 | /* | |
599 | * For statistical analysis of the input data we consider bytes that form a | |
600 | * Galois Field of 256 objects. Each object has an attribute count, ie. how | |
601 | * many times the object appeared in the sample. | |
602 | */ | |
603 | #define BUCKET_SIZE (256) | |
604 | ||
605 | /* | |
606 | * The size of the sample is based on a statistical sampling rule of thumb. | |
607 | * The common way is to perform sampling tests as long as the number of | |
608 | * elements in each cell is at least 5. | |
609 | * | |
610 | * Instead of 5, we choose 32 to obtain more accurate results. | |
611 | * If the data contain the maximum number of symbols, which is 256, we obtain a | |
612 | * sample size bound by 8192. | |
613 | * | |
614 | * For a sample of at most 8KB of data per data range: 16 consecutive bytes | |
615 | * from up to 512 locations. | |
616 | */ | |
617 | #define MAX_SAMPLE_SIZE (BTRFS_MAX_UNCOMPRESSED * \ | |
618 | SAMPLING_READ_SIZE / SAMPLING_INTERVAL) | |
619 | ||
620 | struct bucket_item { | |
621 | u32 count; | |
622 | }; | |
4e439a0b TT |
623 | |
624 | struct heuristic_ws { | |
17b5a6c1 TT |
625 | /* Partial copy of input data */ |
626 | u8 *sample; | |
a440d48c | 627 | u32 sample_size; |
17b5a6c1 TT |
628 | /* Buckets store counters for each byte value */ |
629 | struct bucket_item *bucket; | |
440c840c TT |
630 | /* Sorting buffer */ |
631 | struct bucket_item *bucket_b; | |
4e439a0b TT |
632 | struct list_head list; |
633 | }; | |
634 | ||
92ee5530 DZ |
635 | static struct workspace_manager heuristic_wsm; |
636 | ||
4e439a0b TT |
637 | static void free_heuristic_ws(struct list_head *ws) |
638 | { | |
639 | struct heuristic_ws *workspace; | |
640 | ||
641 | workspace = list_entry(ws, struct heuristic_ws, list); | |
642 | ||
17b5a6c1 TT |
643 | kvfree(workspace->sample); |
644 | kfree(workspace->bucket); | |
440c840c | 645 | kfree(workspace->bucket_b); |
4e439a0b TT |
646 | kfree(workspace); |
647 | } | |
648 | ||
7bf49943 | 649 | static struct list_head *alloc_heuristic_ws(unsigned int level) |
4e439a0b TT |
650 | { |
651 | struct heuristic_ws *ws; | |
652 | ||
653 | ws = kzalloc(sizeof(*ws), GFP_KERNEL); | |
654 | if (!ws) | |
655 | return ERR_PTR(-ENOMEM); | |
656 | ||
17b5a6c1 TT |
657 | ws->sample = kvmalloc(MAX_SAMPLE_SIZE, GFP_KERNEL); |
658 | if (!ws->sample) | |
659 | goto fail; | |
660 | ||
661 | ws->bucket = kcalloc(BUCKET_SIZE, sizeof(*ws->bucket), GFP_KERNEL); | |
662 | if (!ws->bucket) | |
663 | goto fail; | |
4e439a0b | 664 | |
440c840c TT |
665 | ws->bucket_b = kcalloc(BUCKET_SIZE, sizeof(*ws->bucket_b), GFP_KERNEL); |
666 | if (!ws->bucket_b) | |
667 | goto fail; | |
668 | ||
17b5a6c1 | 669 | INIT_LIST_HEAD(&ws->list); |
4e439a0b | 670 | return &ws->list; |
17b5a6c1 TT |
671 | fail: |
672 | free_heuristic_ws(&ws->list); | |
673 | return ERR_PTR(-ENOMEM); | |
4e439a0b TT |
674 | } |
675 | ||
ca4ac360 | 676 | const struct btrfs_compress_op btrfs_heuristic_compress = { |
be951045 | 677 | .workspace_manager = &heuristic_wsm, |
ca4ac360 DZ |
678 | }; |
679 | ||
e8c9f186 | 680 | static const struct btrfs_compress_op * const btrfs_compress_op[] = { |
ca4ac360 DZ |
681 | /* The heuristic is represented as compression type 0 */ |
682 | &btrfs_heuristic_compress, | |
261507a0 | 683 | &btrfs_zlib_compress, |
a6fa6fae | 684 | &btrfs_lzo_compress, |
5c1aab1d | 685 | &btrfs_zstd_compress, |
261507a0 LZ |
686 | }; |
687 | ||
c778df14 DS |
688 | static struct list_head *alloc_workspace(int type, unsigned int level) |
689 | { | |
690 | switch (type) { | |
691 | case BTRFS_COMPRESS_NONE: return alloc_heuristic_ws(level); | |
692 | case BTRFS_COMPRESS_ZLIB: return zlib_alloc_workspace(level); | |
693 | case BTRFS_COMPRESS_LZO: return lzo_alloc_workspace(level); | |
694 | case BTRFS_COMPRESS_ZSTD: return zstd_alloc_workspace(level); | |
695 | default: | |
696 | /* | |
697 | * This can't happen, the type is validated several times | |
698 | * before we get here. | |
699 | */ | |
700 | BUG(); | |
701 | } | |
702 | } | |
703 | ||
1e002351 DS |
704 | static void free_workspace(int type, struct list_head *ws) |
705 | { | |
706 | switch (type) { | |
707 | case BTRFS_COMPRESS_NONE: return free_heuristic_ws(ws); | |
708 | case BTRFS_COMPRESS_ZLIB: return zlib_free_workspace(ws); | |
709 | case BTRFS_COMPRESS_LZO: return lzo_free_workspace(ws); | |
710 | case BTRFS_COMPRESS_ZSTD: return zstd_free_workspace(ws); | |
711 | default: | |
712 | /* | |
713 | * This can't happen, the type is validated several times | |
714 | * before we get here. | |
715 | */ | |
716 | BUG(); | |
717 | } | |
718 | } | |
719 | ||
d5517033 | 720 | static void btrfs_init_workspace_manager(int type) |
261507a0 | 721 | { |
0cf25213 | 722 | struct workspace_manager *wsm; |
4e439a0b | 723 | struct list_head *workspace; |
261507a0 | 724 | |
0cf25213 | 725 | wsm = btrfs_compress_op[type]->workspace_manager; |
92ee5530 DZ |
726 | INIT_LIST_HEAD(&wsm->idle_ws); |
727 | spin_lock_init(&wsm->ws_lock); | |
728 | atomic_set(&wsm->total_ws, 0); | |
729 | init_waitqueue_head(&wsm->ws_wait); | |
f77dd0d6 | 730 | |
1666edab DZ |
731 | /* |
732 | * Preallocate one workspace for each compression type so we can | |
733 | * guarantee forward progress in the worst case | |
734 | */ | |
c778df14 | 735 | workspace = alloc_workspace(type, 0); |
1666edab DZ |
736 | if (IS_ERR(workspace)) { |
737 | pr_warn( | |
738 | "BTRFS: cannot preallocate compression workspace, will try later\n"); | |
739 | } else { | |
92ee5530 DZ |
740 | atomic_set(&wsm->total_ws, 1); |
741 | wsm->free_ws = 1; | |
742 | list_add(workspace, &wsm->idle_ws); | |
1666edab DZ |
743 | } |
744 | } | |
745 | ||
2510307e | 746 | static void btrfs_cleanup_workspace_manager(int type) |
1666edab | 747 | { |
2dba7143 | 748 | struct workspace_manager *wsman; |
1666edab DZ |
749 | struct list_head *ws; |
750 | ||
2dba7143 | 751 | wsman = btrfs_compress_op[type]->workspace_manager; |
1666edab DZ |
752 | while (!list_empty(&wsman->idle_ws)) { |
753 | ws = wsman->idle_ws.next; | |
754 | list_del(ws); | |
1e002351 | 755 | free_workspace(type, ws); |
1666edab | 756 | atomic_dec(&wsman->total_ws); |
261507a0 | 757 | } |
261507a0 LZ |
758 | } |
759 | ||
760 | /* | |
e721e49d DS |
761 | * This finds an available workspace or allocates a new one. |
762 | * If it's not possible to allocate a new one, waits until there's one. | |
763 | * Preallocation makes a forward progress guarantees and we do not return | |
764 | * errors. | |
261507a0 | 765 | */ |
5907a9bb | 766 | struct list_head *btrfs_get_workspace(int type, unsigned int level) |
261507a0 | 767 | { |
5907a9bb | 768 | struct workspace_manager *wsm; |
261507a0 LZ |
769 | struct list_head *workspace; |
770 | int cpus = num_online_cpus(); | |
fe308533 | 771 | unsigned nofs_flag; |
4e439a0b TT |
772 | struct list_head *idle_ws; |
773 | spinlock_t *ws_lock; | |
774 | atomic_t *total_ws; | |
775 | wait_queue_head_t *ws_wait; | |
776 | int *free_ws; | |
777 | ||
5907a9bb | 778 | wsm = btrfs_compress_op[type]->workspace_manager; |
92ee5530 DZ |
779 | idle_ws = &wsm->idle_ws; |
780 | ws_lock = &wsm->ws_lock; | |
781 | total_ws = &wsm->total_ws; | |
782 | ws_wait = &wsm->ws_wait; | |
783 | free_ws = &wsm->free_ws; | |
261507a0 | 784 | |
261507a0 | 785 | again: |
d9187649 BL |
786 | spin_lock(ws_lock); |
787 | if (!list_empty(idle_ws)) { | |
788 | workspace = idle_ws->next; | |
261507a0 | 789 | list_del(workspace); |
6ac10a6a | 790 | (*free_ws)--; |
d9187649 | 791 | spin_unlock(ws_lock); |
261507a0 LZ |
792 | return workspace; |
793 | ||
794 | } | |
6ac10a6a | 795 | if (atomic_read(total_ws) > cpus) { |
261507a0 LZ |
796 | DEFINE_WAIT(wait); |
797 | ||
d9187649 BL |
798 | spin_unlock(ws_lock); |
799 | prepare_to_wait(ws_wait, &wait, TASK_UNINTERRUPTIBLE); | |
6ac10a6a | 800 | if (atomic_read(total_ws) > cpus && !*free_ws) |
261507a0 | 801 | schedule(); |
d9187649 | 802 | finish_wait(ws_wait, &wait); |
261507a0 LZ |
803 | goto again; |
804 | } | |
6ac10a6a | 805 | atomic_inc(total_ws); |
d9187649 | 806 | spin_unlock(ws_lock); |
261507a0 | 807 | |
fe308533 DS |
808 | /* |
809 | * Allocation helpers call vmalloc that can't use GFP_NOFS, so we have | |
810 | * to turn it off here because we might get called from the restricted | |
811 | * context of btrfs_compress_bio/btrfs_compress_pages | |
812 | */ | |
813 | nofs_flag = memalloc_nofs_save(); | |
c778df14 | 814 | workspace = alloc_workspace(type, level); |
fe308533 DS |
815 | memalloc_nofs_restore(nofs_flag); |
816 | ||
261507a0 | 817 | if (IS_ERR(workspace)) { |
6ac10a6a | 818 | atomic_dec(total_ws); |
d9187649 | 819 | wake_up(ws_wait); |
e721e49d DS |
820 | |
821 | /* | |
822 | * Do not return the error but go back to waiting. There's a | |
823 | * workspace preallocated for each type and the compression | |
824 | * time is bounded so we get to a workspace eventually. This | |
825 | * makes our caller's life easier. | |
52356716 DS |
826 | * |
827 | * To prevent silent and low-probability deadlocks (when the | |
828 | * initial preallocation fails), check if there are any | |
829 | * workspaces at all. | |
e721e49d | 830 | */ |
52356716 DS |
831 | if (atomic_read(total_ws) == 0) { |
832 | static DEFINE_RATELIMIT_STATE(_rs, | |
833 | /* once per minute */ 60 * HZ, | |
834 | /* no burst */ 1); | |
835 | ||
836 | if (__ratelimit(&_rs)) { | |
ab8d0fc4 | 837 | pr_warn("BTRFS: no compression workspaces, low memory, retrying\n"); |
52356716 DS |
838 | } |
839 | } | |
e721e49d | 840 | goto again; |
261507a0 LZ |
841 | } |
842 | return workspace; | |
843 | } | |
844 | ||
7bf49943 | 845 | static struct list_head *get_workspace(int type, int level) |
929f4baf | 846 | { |
6a0d1272 | 847 | switch (type) { |
5907a9bb | 848 | case BTRFS_COMPRESS_NONE: return btrfs_get_workspace(type, level); |
6a0d1272 | 849 | case BTRFS_COMPRESS_ZLIB: return zlib_get_workspace(level); |
5907a9bb | 850 | case BTRFS_COMPRESS_LZO: return btrfs_get_workspace(type, level); |
6a0d1272 DS |
851 | case BTRFS_COMPRESS_ZSTD: return zstd_get_workspace(level); |
852 | default: | |
853 | /* | |
854 | * This can't happen, the type is validated several times | |
855 | * before we get here. | |
856 | */ | |
857 | BUG(); | |
858 | } | |
929f4baf DZ |
859 | } |
860 | ||
261507a0 LZ |
861 | /* |
862 | * put a workspace struct back on the list or free it if we have enough | |
863 | * idle ones sitting around | |
864 | */ | |
a3bbd2a9 | 865 | void btrfs_put_workspace(int type, struct list_head *ws) |
261507a0 | 866 | { |
a3bbd2a9 | 867 | struct workspace_manager *wsm; |
4e439a0b TT |
868 | struct list_head *idle_ws; |
869 | spinlock_t *ws_lock; | |
870 | atomic_t *total_ws; | |
871 | wait_queue_head_t *ws_wait; | |
872 | int *free_ws; | |
873 | ||
a3bbd2a9 | 874 | wsm = btrfs_compress_op[type]->workspace_manager; |
92ee5530 DZ |
875 | idle_ws = &wsm->idle_ws; |
876 | ws_lock = &wsm->ws_lock; | |
877 | total_ws = &wsm->total_ws; | |
878 | ws_wait = &wsm->ws_wait; | |
879 | free_ws = &wsm->free_ws; | |
d9187649 BL |
880 | |
881 | spin_lock(ws_lock); | |
26b28dce | 882 | if (*free_ws <= num_online_cpus()) { |
929f4baf | 883 | list_add(ws, idle_ws); |
6ac10a6a | 884 | (*free_ws)++; |
d9187649 | 885 | spin_unlock(ws_lock); |
261507a0 LZ |
886 | goto wake; |
887 | } | |
d9187649 | 888 | spin_unlock(ws_lock); |
261507a0 | 889 | |
1e002351 | 890 | free_workspace(type, ws); |
6ac10a6a | 891 | atomic_dec(total_ws); |
261507a0 | 892 | wake: |
093258e6 | 893 | cond_wake_up(ws_wait); |
261507a0 LZ |
894 | } |
895 | ||
929f4baf DZ |
896 | static void put_workspace(int type, struct list_head *ws) |
897 | { | |
bd3a5287 | 898 | switch (type) { |
a3bbd2a9 DS |
899 | case BTRFS_COMPRESS_NONE: return btrfs_put_workspace(type, ws); |
900 | case BTRFS_COMPRESS_ZLIB: return btrfs_put_workspace(type, ws); | |
901 | case BTRFS_COMPRESS_LZO: return btrfs_put_workspace(type, ws); | |
bd3a5287 DS |
902 | case BTRFS_COMPRESS_ZSTD: return zstd_put_workspace(ws); |
903 | default: | |
904 | /* | |
905 | * This can't happen, the type is validated several times | |
906 | * before we get here. | |
907 | */ | |
908 | BUG(); | |
909 | } | |
929f4baf DZ |
910 | } |
911 | ||
adbab642 AJ |
912 | /* |
913 | * Adjust @level according to the limits of the compression algorithm or | |
914 | * fallback to default | |
915 | */ | |
916 | static unsigned int btrfs_compress_set_level(int type, unsigned level) | |
917 | { | |
918 | const struct btrfs_compress_op *ops = btrfs_compress_op[type]; | |
919 | ||
920 | if (level == 0) | |
921 | level = ops->default_level; | |
922 | else | |
923 | level = min(level, ops->max_level); | |
924 | ||
925 | return level; | |
926 | } | |
927 | ||
261507a0 | 928 | /* |
38c31464 DS |
929 | * Given an address space and start and length, compress the bytes into @pages |
930 | * that are allocated on demand. | |
261507a0 | 931 | * |
f51d2b59 DS |
932 | * @type_level is encoded algorithm and level, where level 0 means whatever |
933 | * default the algorithm chooses and is opaque here; | |
934 | * - compression algo are 0-3 | |
935 | * - the level are bits 4-7 | |
936 | * | |
4d3a800e DS |
937 | * @out_pages is an in/out parameter, holds maximum number of pages to allocate |
938 | * and returns number of actually allocated pages | |
261507a0 | 939 | * |
38c31464 DS |
940 | * @total_in is used to return the number of bytes actually read. It |
941 | * may be smaller than the input length if we had to exit early because we | |
261507a0 LZ |
942 | * ran out of room in the pages array or because we cross the |
943 | * max_out threshold. | |
944 | * | |
38c31464 DS |
945 | * @total_out is an in/out parameter, must be set to the input length and will |
946 | * be also used to return the total number of compressed bytes | |
261507a0 | 947 | */ |
f51d2b59 | 948 | int btrfs_compress_pages(unsigned int type_level, struct address_space *mapping, |
38c31464 | 949 | u64 start, struct page **pages, |
261507a0 LZ |
950 | unsigned long *out_pages, |
951 | unsigned long *total_in, | |
e5d74902 | 952 | unsigned long *total_out) |
261507a0 | 953 | { |
1972708a | 954 | int type = btrfs_compress_type(type_level); |
7bf49943 | 955 | int level = btrfs_compress_level(type_level); |
261507a0 LZ |
956 | struct list_head *workspace; |
957 | int ret; | |
958 | ||
b0c1fe1e | 959 | level = btrfs_compress_set_level(type, level); |
7bf49943 | 960 | workspace = get_workspace(type, level); |
1e4eb746 DS |
961 | ret = compression_compress_pages(type, workspace, mapping, start, pages, |
962 | out_pages, total_in, total_out); | |
929f4baf | 963 | put_workspace(type, workspace); |
261507a0 LZ |
964 | return ret; |
965 | } | |
966 | ||
8140dc30 | 967 | static int btrfs_decompress_bio(struct compressed_bio *cb) |
261507a0 LZ |
968 | { |
969 | struct list_head *workspace; | |
970 | int ret; | |
8140dc30 | 971 | int type = cb->compress_type; |
261507a0 | 972 | |
7bf49943 | 973 | workspace = get_workspace(type, 0); |
4a9e803e | 974 | ret = compression_decompress_bio(workspace, cb); |
929f4baf | 975 | put_workspace(type, workspace); |
e1ddce71 | 976 | |
261507a0 LZ |
977 | return ret; |
978 | } | |
979 | ||
980 | /* | |
981 | * a less complex decompression routine. Our compressed data fits in a | |
982 | * single page, and we want to read a single page out of it. | |
983 | * start_byte tells us the offset into the compressed data we're interested in | |
984 | */ | |
3e09b5b2 | 985 | int btrfs_decompress(int type, const u8 *data_in, struct page *dest_page, |
261507a0 LZ |
986 | unsigned long start_byte, size_t srclen, size_t destlen) |
987 | { | |
988 | struct list_head *workspace; | |
989 | int ret; | |
990 | ||
7bf49943 | 991 | workspace = get_workspace(type, 0); |
1e4eb746 DS |
992 | ret = compression_decompress(type, workspace, data_in, dest_page, |
993 | start_byte, srclen, destlen); | |
929f4baf | 994 | put_workspace(type, workspace); |
7bf49943 | 995 | |
261507a0 LZ |
996 | return ret; |
997 | } | |
998 | ||
5565b8e0 | 999 | int __init btrfs_init_compress(void) |
1666edab | 1000 | { |
544fe4a9 CH |
1001 | if (bioset_init(&btrfs_compressed_bioset, BIO_POOL_SIZE, |
1002 | offsetof(struct compressed_bio, bbio.bio), | |
1003 | BIOSET_NEED_BVECS)) | |
1004 | return -ENOMEM; | |
d5517033 DS |
1005 | btrfs_init_workspace_manager(BTRFS_COMPRESS_NONE); |
1006 | btrfs_init_workspace_manager(BTRFS_COMPRESS_ZLIB); | |
1007 | btrfs_init_workspace_manager(BTRFS_COMPRESS_LZO); | |
1008 | zstd_init_workspace_manager(); | |
5565b8e0 | 1009 | return 0; |
1666edab DZ |
1010 | } |
1011 | ||
e67c718b | 1012 | void __cold btrfs_exit_compress(void) |
261507a0 | 1013 | { |
2510307e DS |
1014 | btrfs_cleanup_workspace_manager(BTRFS_COMPRESS_NONE); |
1015 | btrfs_cleanup_workspace_manager(BTRFS_COMPRESS_ZLIB); | |
1016 | btrfs_cleanup_workspace_manager(BTRFS_COMPRESS_LZO); | |
1017 | zstd_cleanup_workspace_manager(); | |
544fe4a9 | 1018 | bioset_exit(&btrfs_compressed_bioset); |
261507a0 | 1019 | } |
3a39c18d LZ |
1020 | |
1021 | /* | |
1c3dc173 | 1022 | * Copy decompressed data from working buffer to pages. |
3a39c18d | 1023 | * |
1c3dc173 QW |
1024 | * @buf: The decompressed data buffer |
1025 | * @buf_len: The decompressed data length | |
1026 | * @decompressed: Number of bytes that are already decompressed inside the | |
1027 | * compressed extent | |
1028 | * @cb: The compressed extent descriptor | |
1029 | * @orig_bio: The original bio that the caller wants to read for | |
3a39c18d | 1030 | * |
1c3dc173 QW |
1031 | * An easier to understand graph is like below: |
1032 | * | |
1033 | * |<- orig_bio ->| |<- orig_bio->| | |
1034 | * |<------- full decompressed extent ----->| | |
1035 | * |<----------- @cb range ---->| | |
1036 | * | |<-- @buf_len -->| | |
1037 | * |<--- @decompressed --->| | |
1038 | * | |
1039 | * Note that, @cb can be a subpage of the full decompressed extent, but | |
1040 | * @cb->start always has the same as the orig_file_offset value of the full | |
1041 | * decompressed extent. | |
1042 | * | |
1043 | * When reading compressed extent, we have to read the full compressed extent, | |
1044 | * while @orig_bio may only want part of the range. | |
1045 | * Thus this function will ensure only data covered by @orig_bio will be copied | |
1046 | * to. | |
1047 | * | |
1048 | * Return 0 if we have copied all needed contents for @orig_bio. | |
1049 | * Return >0 if we need continue decompress. | |
3a39c18d | 1050 | */ |
1c3dc173 QW |
1051 | int btrfs_decompress_buf2page(const char *buf, u32 buf_len, |
1052 | struct compressed_bio *cb, u32 decompressed) | |
3a39c18d | 1053 | { |
1c3dc173 QW |
1054 | struct bio *orig_bio = cb->orig_bio; |
1055 | /* Offset inside the full decompressed extent */ | |
1056 | u32 cur_offset; | |
1057 | ||
1058 | cur_offset = decompressed; | |
1059 | /* The main loop to do the copy */ | |
1060 | while (cur_offset < decompressed + buf_len) { | |
1061 | struct bio_vec bvec; | |
1062 | size_t copy_len; | |
1063 | u32 copy_start; | |
1064 | /* Offset inside the full decompressed extent */ | |
1065 | u32 bvec_offset; | |
1066 | ||
1067 | bvec = bio_iter_iovec(orig_bio, orig_bio->bi_iter); | |
1068 | /* | |
1069 | * cb->start may underflow, but subtracting that value can still | |
1070 | * give us correct offset inside the full decompressed extent. | |
1071 | */ | |
1072 | bvec_offset = page_offset(bvec.bv_page) + bvec.bv_offset - cb->start; | |
974b1adc | 1073 | |
1c3dc173 QW |
1074 | /* Haven't reached the bvec range, exit */ |
1075 | if (decompressed + buf_len <= bvec_offset) | |
1076 | return 1; | |
3a39c18d | 1077 | |
1c3dc173 QW |
1078 | copy_start = max(cur_offset, bvec_offset); |
1079 | copy_len = min(bvec_offset + bvec.bv_len, | |
1080 | decompressed + buf_len) - copy_start; | |
1081 | ASSERT(copy_len); | |
3a39c18d | 1082 | |
974b1adc | 1083 | /* |
1c3dc173 QW |
1084 | * Extra range check to ensure we didn't go beyond |
1085 | * @buf + @buf_len. | |
974b1adc | 1086 | */ |
1c3dc173 QW |
1087 | ASSERT(copy_start - decompressed < buf_len); |
1088 | memcpy_to_page(bvec.bv_page, bvec.bv_offset, | |
1089 | buf + copy_start - decompressed, copy_len); | |
1c3dc173 | 1090 | cur_offset += copy_len; |
3a39c18d | 1091 | |
1c3dc173 QW |
1092 | bio_advance(orig_bio, copy_len); |
1093 | /* Finished the bio */ | |
1094 | if (!orig_bio->bi_iter.bi_size) | |
1095 | return 0; | |
3a39c18d | 1096 | } |
3a39c18d LZ |
1097 | return 1; |
1098 | } | |
c2fcdcdf | 1099 | |
19562430 TT |
1100 | /* |
1101 | * Shannon Entropy calculation | |
1102 | * | |
52042d8e | 1103 | * Pure byte distribution analysis fails to determine compressibility of data. |
19562430 TT |
1104 | * Try calculating entropy to estimate the average minimum number of bits |
1105 | * needed to encode the sampled data. | |
1106 | * | |
1107 | * For convenience, return the percentage of needed bits, instead of amount of | |
1108 | * bits directly. | |
1109 | * | |
1110 | * @ENTROPY_LVL_ACEPTABLE - below that threshold, sample has low byte entropy | |
1111 | * and can be compressible with high probability | |
1112 | * | |
1113 | * @ENTROPY_LVL_HIGH - data are not compressible with high probability | |
1114 | * | |
1115 | * Use of ilog2() decreases precision, we lower the LVL to 5 to compensate. | |
1116 | */ | |
1117 | #define ENTROPY_LVL_ACEPTABLE (65) | |
1118 | #define ENTROPY_LVL_HIGH (80) | |
1119 | ||
1120 | /* | |
1121 | * For increasead precision in shannon_entropy calculation, | |
1122 | * let's do pow(n, M) to save more digits after comma: | |
1123 | * | |
1124 | * - maximum int bit length is 64 | |
1125 | * - ilog2(MAX_SAMPLE_SIZE) -> 13 | |
1126 | * - 13 * 4 = 52 < 64 -> M = 4 | |
1127 | * | |
1128 | * So use pow(n, 4). | |
1129 | */ | |
1130 | static inline u32 ilog2_w(u64 n) | |
1131 | { | |
1132 | return ilog2(n * n * n * n); | |
1133 | } | |
1134 | ||
1135 | static u32 shannon_entropy(struct heuristic_ws *ws) | |
1136 | { | |
1137 | const u32 entropy_max = 8 * ilog2_w(2); | |
1138 | u32 entropy_sum = 0; | |
1139 | u32 p, p_base, sz_base; | |
1140 | u32 i; | |
1141 | ||
1142 | sz_base = ilog2_w(ws->sample_size); | |
1143 | for (i = 0; i < BUCKET_SIZE && ws->bucket[i].count > 0; i++) { | |
1144 | p = ws->bucket[i].count; | |
1145 | p_base = ilog2_w(p); | |
1146 | entropy_sum += p * (sz_base - p_base); | |
1147 | } | |
1148 | ||
1149 | entropy_sum /= ws->sample_size; | |
1150 | return entropy_sum * 100 / entropy_max; | |
1151 | } | |
1152 | ||
440c840c TT |
1153 | #define RADIX_BASE 4U |
1154 | #define COUNTERS_SIZE (1U << RADIX_BASE) | |
1155 | ||
1156 | static u8 get4bits(u64 num, int shift) { | |
1157 | u8 low4bits; | |
1158 | ||
1159 | num >>= shift; | |
1160 | /* Reverse order */ | |
1161 | low4bits = (COUNTERS_SIZE - 1) - (num % COUNTERS_SIZE); | |
1162 | return low4bits; | |
1163 | } | |
1164 | ||
440c840c TT |
1165 | /* |
1166 | * Use 4 bits as radix base | |
52042d8e | 1167 | * Use 16 u32 counters for calculating new position in buf array |
440c840c TT |
1168 | * |
1169 | * @array - array that will be sorted | |
1170 | * @array_buf - buffer array to store sorting results | |
1171 | * must be equal in size to @array | |
1172 | * @num - array size | |
440c840c | 1173 | */ |
23ae8c63 | 1174 | static void radix_sort(struct bucket_item *array, struct bucket_item *array_buf, |
36243c91 | 1175 | int num) |
858177d3 | 1176 | { |
440c840c TT |
1177 | u64 max_num; |
1178 | u64 buf_num; | |
1179 | u32 counters[COUNTERS_SIZE]; | |
1180 | u32 new_addr; | |
1181 | u32 addr; | |
1182 | int bitlen; | |
1183 | int shift; | |
1184 | int i; | |
858177d3 | 1185 | |
440c840c TT |
1186 | /* |
1187 | * Try avoid useless loop iterations for small numbers stored in big | |
1188 | * counters. Example: 48 33 4 ... in 64bit array | |
1189 | */ | |
23ae8c63 | 1190 | max_num = array[0].count; |
440c840c | 1191 | for (i = 1; i < num; i++) { |
23ae8c63 | 1192 | buf_num = array[i].count; |
440c840c TT |
1193 | if (buf_num > max_num) |
1194 | max_num = buf_num; | |
1195 | } | |
1196 | ||
1197 | buf_num = ilog2(max_num); | |
1198 | bitlen = ALIGN(buf_num, RADIX_BASE * 2); | |
1199 | ||
1200 | shift = 0; | |
1201 | while (shift < bitlen) { | |
1202 | memset(counters, 0, sizeof(counters)); | |
1203 | ||
1204 | for (i = 0; i < num; i++) { | |
23ae8c63 | 1205 | buf_num = array[i].count; |
440c840c TT |
1206 | addr = get4bits(buf_num, shift); |
1207 | counters[addr]++; | |
1208 | } | |
1209 | ||
1210 | for (i = 1; i < COUNTERS_SIZE; i++) | |
1211 | counters[i] += counters[i - 1]; | |
1212 | ||
1213 | for (i = num - 1; i >= 0; i--) { | |
23ae8c63 | 1214 | buf_num = array[i].count; |
440c840c TT |
1215 | addr = get4bits(buf_num, shift); |
1216 | counters[addr]--; | |
1217 | new_addr = counters[addr]; | |
7add17be | 1218 | array_buf[new_addr] = array[i]; |
440c840c TT |
1219 | } |
1220 | ||
1221 | shift += RADIX_BASE; | |
1222 | ||
1223 | /* | |
1224 | * Normal radix expects to move data from a temporary array, to | |
1225 | * the main one. But that requires some CPU time. Avoid that | |
1226 | * by doing another sort iteration to original array instead of | |
1227 | * memcpy() | |
1228 | */ | |
1229 | memset(counters, 0, sizeof(counters)); | |
1230 | ||
1231 | for (i = 0; i < num; i ++) { | |
23ae8c63 | 1232 | buf_num = array_buf[i].count; |
440c840c TT |
1233 | addr = get4bits(buf_num, shift); |
1234 | counters[addr]++; | |
1235 | } | |
1236 | ||
1237 | for (i = 1; i < COUNTERS_SIZE; i++) | |
1238 | counters[i] += counters[i - 1]; | |
1239 | ||
1240 | for (i = num - 1; i >= 0; i--) { | |
23ae8c63 | 1241 | buf_num = array_buf[i].count; |
440c840c TT |
1242 | addr = get4bits(buf_num, shift); |
1243 | counters[addr]--; | |
1244 | new_addr = counters[addr]; | |
7add17be | 1245 | array[new_addr] = array_buf[i]; |
440c840c TT |
1246 | } |
1247 | ||
1248 | shift += RADIX_BASE; | |
1249 | } | |
858177d3 TT |
1250 | } |
1251 | ||
1252 | /* | |
1253 | * Size of the core byte set - how many bytes cover 90% of the sample | |
1254 | * | |
1255 | * There are several types of structured binary data that use nearly all byte | |
1256 | * values. The distribution can be uniform and counts in all buckets will be | |
1257 | * nearly the same (eg. encrypted data). Unlikely to be compressible. | |
1258 | * | |
1259 | * Other possibility is normal (Gaussian) distribution, where the data could | |
1260 | * be potentially compressible, but we have to take a few more steps to decide | |
1261 | * how much. | |
1262 | * | |
1263 | * @BYTE_CORE_SET_LOW - main part of byte values repeated frequently, | |
1264 | * compression algo can easy fix that | |
1265 | * @BYTE_CORE_SET_HIGH - data have uniform distribution and with high | |
1266 | * probability is not compressible | |
1267 | */ | |
1268 | #define BYTE_CORE_SET_LOW (64) | |
1269 | #define BYTE_CORE_SET_HIGH (200) | |
1270 | ||
1271 | static int byte_core_set_size(struct heuristic_ws *ws) | |
1272 | { | |
1273 | u32 i; | |
1274 | u32 coreset_sum = 0; | |
1275 | const u32 core_set_threshold = ws->sample_size * 90 / 100; | |
1276 | struct bucket_item *bucket = ws->bucket; | |
1277 | ||
1278 | /* Sort in reverse order */ | |
36243c91 | 1279 | radix_sort(ws->bucket, ws->bucket_b, BUCKET_SIZE); |
858177d3 TT |
1280 | |
1281 | for (i = 0; i < BYTE_CORE_SET_LOW; i++) | |
1282 | coreset_sum += bucket[i].count; | |
1283 | ||
1284 | if (coreset_sum > core_set_threshold) | |
1285 | return i; | |
1286 | ||
1287 | for (; i < BYTE_CORE_SET_HIGH && bucket[i].count > 0; i++) { | |
1288 | coreset_sum += bucket[i].count; | |
1289 | if (coreset_sum > core_set_threshold) | |
1290 | break; | |
1291 | } | |
1292 | ||
1293 | return i; | |
1294 | } | |
1295 | ||
a288e92c TT |
1296 | /* |
1297 | * Count byte values in buckets. | |
1298 | * This heuristic can detect textual data (configs, xml, json, html, etc). | |
1299 | * Because in most text-like data byte set is restricted to limited number of | |
1300 | * possible characters, and that restriction in most cases makes data easy to | |
1301 | * compress. | |
1302 | * | |
1303 | * @BYTE_SET_THRESHOLD - consider all data within this byte set size: | |
1304 | * less - compressible | |
1305 | * more - need additional analysis | |
1306 | */ | |
1307 | #define BYTE_SET_THRESHOLD (64) | |
1308 | ||
1309 | static u32 byte_set_size(const struct heuristic_ws *ws) | |
1310 | { | |
1311 | u32 i; | |
1312 | u32 byte_set_size = 0; | |
1313 | ||
1314 | for (i = 0; i < BYTE_SET_THRESHOLD; i++) { | |
1315 | if (ws->bucket[i].count > 0) | |
1316 | byte_set_size++; | |
1317 | } | |
1318 | ||
1319 | /* | |
1320 | * Continue collecting count of byte values in buckets. If the byte | |
1321 | * set size is bigger then the threshold, it's pointless to continue, | |
1322 | * the detection technique would fail for this type of data. | |
1323 | */ | |
1324 | for (; i < BUCKET_SIZE; i++) { | |
1325 | if (ws->bucket[i].count > 0) { | |
1326 | byte_set_size++; | |
1327 | if (byte_set_size > BYTE_SET_THRESHOLD) | |
1328 | return byte_set_size; | |
1329 | } | |
1330 | } | |
1331 | ||
1332 | return byte_set_size; | |
1333 | } | |
1334 | ||
1fe4f6fa TT |
1335 | static bool sample_repeated_patterns(struct heuristic_ws *ws) |
1336 | { | |
1337 | const u32 half_of_sample = ws->sample_size / 2; | |
1338 | const u8 *data = ws->sample; | |
1339 | ||
1340 | return memcmp(&data[0], &data[half_of_sample], half_of_sample) == 0; | |
1341 | } | |
1342 | ||
a440d48c TT |
1343 | static void heuristic_collect_sample(struct inode *inode, u64 start, u64 end, |
1344 | struct heuristic_ws *ws) | |
1345 | { | |
1346 | struct page *page; | |
1347 | u64 index, index_end; | |
1348 | u32 i, curr_sample_pos; | |
1349 | u8 *in_data; | |
1350 | ||
1351 | /* | |
1352 | * Compression handles the input data by chunks of 128KiB | |
1353 | * (defined by BTRFS_MAX_UNCOMPRESSED) | |
1354 | * | |
1355 | * We do the same for the heuristic and loop over the whole range. | |
1356 | * | |
1357 | * MAX_SAMPLE_SIZE - calculated under assumption that heuristic will | |
1358 | * process no more than BTRFS_MAX_UNCOMPRESSED at a time. | |
1359 | */ | |
1360 | if (end - start > BTRFS_MAX_UNCOMPRESSED) | |
1361 | end = start + BTRFS_MAX_UNCOMPRESSED; | |
1362 | ||
1363 | index = start >> PAGE_SHIFT; | |
1364 | index_end = end >> PAGE_SHIFT; | |
1365 | ||
1366 | /* Don't miss unaligned end */ | |
ce394a7f | 1367 | if (!PAGE_ALIGNED(end)) |
a440d48c TT |
1368 | index_end++; |
1369 | ||
1370 | curr_sample_pos = 0; | |
1371 | while (index < index_end) { | |
1372 | page = find_get_page(inode->i_mapping, index); | |
58c1a35c | 1373 | in_data = kmap_local_page(page); |
a440d48c TT |
1374 | /* Handle case where the start is not aligned to PAGE_SIZE */ |
1375 | i = start % PAGE_SIZE; | |
1376 | while (i < PAGE_SIZE - SAMPLING_READ_SIZE) { | |
1377 | /* Don't sample any garbage from the last page */ | |
1378 | if (start > end - SAMPLING_READ_SIZE) | |
1379 | break; | |
1380 | memcpy(&ws->sample[curr_sample_pos], &in_data[i], | |
1381 | SAMPLING_READ_SIZE); | |
1382 | i += SAMPLING_INTERVAL; | |
1383 | start += SAMPLING_INTERVAL; | |
1384 | curr_sample_pos += SAMPLING_READ_SIZE; | |
1385 | } | |
58c1a35c | 1386 | kunmap_local(in_data); |
a440d48c TT |
1387 | put_page(page); |
1388 | ||
1389 | index++; | |
1390 | } | |
1391 | ||
1392 | ws->sample_size = curr_sample_pos; | |
1393 | } | |
1394 | ||
c2fcdcdf TT |
1395 | /* |
1396 | * Compression heuristic. | |
1397 | * | |
1398 | * For now is's a naive and optimistic 'return true', we'll extend the logic to | |
1399 | * quickly (compared to direct compression) detect data characteristics | |
67da05b3 | 1400 | * (compressible/incompressible) to avoid wasting CPU time on incompressible |
c2fcdcdf TT |
1401 | * data. |
1402 | * | |
1403 | * The following types of analysis can be performed: | |
1404 | * - detect mostly zero data | |
1405 | * - detect data with low "byte set" size (text, etc) | |
1406 | * - detect data with low/high "core byte" set | |
1407 | * | |
1408 | * Return non-zero if the compression should be done, 0 otherwise. | |
1409 | */ | |
1410 | int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) | |
1411 | { | |
7bf49943 | 1412 | struct list_head *ws_list = get_workspace(0, 0); |
4e439a0b | 1413 | struct heuristic_ws *ws; |
a440d48c TT |
1414 | u32 i; |
1415 | u8 byte; | |
19562430 | 1416 | int ret = 0; |
c2fcdcdf | 1417 | |
4e439a0b TT |
1418 | ws = list_entry(ws_list, struct heuristic_ws, list); |
1419 | ||
a440d48c TT |
1420 | heuristic_collect_sample(inode, start, end, ws); |
1421 | ||
1fe4f6fa TT |
1422 | if (sample_repeated_patterns(ws)) { |
1423 | ret = 1; | |
1424 | goto out; | |
1425 | } | |
1426 | ||
a440d48c TT |
1427 | memset(ws->bucket, 0, sizeof(*ws->bucket)*BUCKET_SIZE); |
1428 | ||
1429 | for (i = 0; i < ws->sample_size; i++) { | |
1430 | byte = ws->sample[i]; | |
1431 | ws->bucket[byte].count++; | |
c2fcdcdf TT |
1432 | } |
1433 | ||
a288e92c TT |
1434 | i = byte_set_size(ws); |
1435 | if (i < BYTE_SET_THRESHOLD) { | |
1436 | ret = 2; | |
1437 | goto out; | |
1438 | } | |
1439 | ||
858177d3 TT |
1440 | i = byte_core_set_size(ws); |
1441 | if (i <= BYTE_CORE_SET_LOW) { | |
1442 | ret = 3; | |
1443 | goto out; | |
1444 | } | |
1445 | ||
1446 | if (i >= BYTE_CORE_SET_HIGH) { | |
1447 | ret = 0; | |
1448 | goto out; | |
1449 | } | |
1450 | ||
19562430 TT |
1451 | i = shannon_entropy(ws); |
1452 | if (i <= ENTROPY_LVL_ACEPTABLE) { | |
1453 | ret = 4; | |
1454 | goto out; | |
1455 | } | |
1456 | ||
1457 | /* | |
1458 | * For the levels below ENTROPY_LVL_HIGH, additional analysis would be | |
1459 | * needed to give green light to compression. | |
1460 | * | |
1461 | * For now just assume that compression at that level is not worth the | |
1462 | * resources because: | |
1463 | * | |
1464 | * 1. it is possible to defrag the data later | |
1465 | * | |
1466 | * 2. the data would turn out to be hardly compressible, eg. 150 byte | |
1467 | * values, every bucket has counter at level ~54. The heuristic would | |
1468 | * be confused. This can happen when data have some internal repeated | |
1469 | * patterns like "abbacbbc...". This can be detected by analyzing | |
1470 | * pairs of bytes, which is too costly. | |
1471 | */ | |
1472 | if (i < ENTROPY_LVL_HIGH) { | |
1473 | ret = 5; | |
1474 | goto out; | |
1475 | } else { | |
1476 | ret = 0; | |
1477 | goto out; | |
1478 | } | |
1479 | ||
1fe4f6fa | 1480 | out: |
929f4baf | 1481 | put_workspace(0, ws_list); |
c2fcdcdf TT |
1482 | return ret; |
1483 | } | |
f51d2b59 | 1484 | |
d0ab62ce DZ |
1485 | /* |
1486 | * Convert the compression suffix (eg. after "zlib" starting with ":") to | |
1487 | * level, unrecognized string will set the default level | |
1488 | */ | |
1489 | unsigned int btrfs_compress_str2level(unsigned int type, const char *str) | |
f51d2b59 | 1490 | { |
d0ab62ce DZ |
1491 | unsigned int level = 0; |
1492 | int ret; | |
1493 | ||
1494 | if (!type) | |
f51d2b59 DS |
1495 | return 0; |
1496 | ||
d0ab62ce DZ |
1497 | if (str[0] == ':') { |
1498 | ret = kstrtouint(str + 1, 10, &level); | |
1499 | if (ret) | |
1500 | level = 0; | |
1501 | } | |
1502 | ||
b0c1fe1e DS |
1503 | level = btrfs_compress_set_level(type, level); |
1504 | ||
1505 | return level; | |
1506 | } |