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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2016-present, Facebook, Inc.
4 * All rights reserved.
5 *
6 */
7
8#include <linux/bio.h>
9#include <linux/err.h>
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/mm.h>
13#include <linux/pagemap.h>
14#include <linux/refcount.h>
15#include <linux/sched.h>
16#include <linux/slab.h>
17#include <linux/zstd.h>
18#include "compression.h"
19
20#define ZSTD_BTRFS_MAX_WINDOWLOG 17
21#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
22#define ZSTD_BTRFS_DEFAULT_LEVEL 3
23
24static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len)
25{
26 ZSTD_parameters params = ZSTD_getParams(ZSTD_BTRFS_DEFAULT_LEVEL,
27 src_len, 0);
28
29 if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG)
30 params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG;
31 WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT);
32 return params;
33}
34
35struct workspace {
36 void *mem;
37 size_t size;
38 char *buf;
39 struct list_head list;
40 ZSTD_inBuffer in_buf;
41 ZSTD_outBuffer out_buf;
42};
43
44static void zstd_free_workspace(struct list_head *ws)
45{
46 struct workspace *workspace = list_entry(ws, struct workspace, list);
47
48 kvfree(workspace->mem);
49 kfree(workspace->buf);
50 kfree(workspace);
51}
52
53static struct list_head *zstd_alloc_workspace(void)
54{
55 ZSTD_parameters params =
56 zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
57 struct workspace *workspace;
58
59 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
60 if (!workspace)
61 return ERR_PTR(-ENOMEM);
62
63 workspace->size = max_t(size_t,
64 ZSTD_CStreamWorkspaceBound(params.cParams),
65 ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
66 workspace->mem = kvmalloc(workspace->size, GFP_KERNEL);
67 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
68 if (!workspace->mem || !workspace->buf)
69 goto fail;
70
71 INIT_LIST_HEAD(&workspace->list);
72
73 return &workspace->list;
74fail:
75 zstd_free_workspace(&workspace->list);
76 return ERR_PTR(-ENOMEM);
77}
78
79static int zstd_compress_pages(struct list_head *ws,
80 struct address_space *mapping,
81 u64 start,
82 struct page **pages,
83 unsigned long *out_pages,
84 unsigned long *total_in,
85 unsigned long *total_out)
86{
87 struct workspace *workspace = list_entry(ws, struct workspace, list);
88 ZSTD_CStream *stream;
89 int ret = 0;
90 int nr_pages = 0;
91 struct page *in_page = NULL; /* The current page to read */
92 struct page *out_page = NULL; /* The current page to write to */
93 unsigned long tot_in = 0;
94 unsigned long tot_out = 0;
95 unsigned long len = *total_out;
96 const unsigned long nr_dest_pages = *out_pages;
97 unsigned long max_out = nr_dest_pages * PAGE_SIZE;
98 ZSTD_parameters params = zstd_get_btrfs_parameters(len);
99
100 *out_pages = 0;
101 *total_out = 0;
102 *total_in = 0;
103
104 /* Initialize the stream */
105 stream = ZSTD_initCStream(params, len, workspace->mem,
106 workspace->size);
107 if (!stream) {
108 pr_warn("BTRFS: ZSTD_initCStream failed\n");
109 ret = -EIO;
110 goto out;
111 }
112
113 /* map in the first page of input data */
114 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
115 workspace->in_buf.src = kmap(in_page);
116 workspace->in_buf.pos = 0;
117 workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
118
119
120 /* Allocate and map in the output buffer */
121 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
122 if (out_page == NULL) {
123 ret = -ENOMEM;
124 goto out;
125 }
126 pages[nr_pages++] = out_page;
127 workspace->out_buf.dst = kmap(out_page);
128 workspace->out_buf.pos = 0;
129 workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
130
131 while (1) {
132 size_t ret2;
133
134 ret2 = ZSTD_compressStream(stream, &workspace->out_buf,
135 &workspace->in_buf);
136 if (ZSTD_isError(ret2)) {
137 pr_debug("BTRFS: ZSTD_compressStream returned %d\n",
138 ZSTD_getErrorCode(ret2));
139 ret = -EIO;
140 goto out;
141 }
142
143 /* Check to see if we are making it bigger */
144 if (tot_in + workspace->in_buf.pos > 8192 &&
145 tot_in + workspace->in_buf.pos <
146 tot_out + workspace->out_buf.pos) {
147 ret = -E2BIG;
148 goto out;
149 }
150
151 /* We've reached the end of our output range */
152 if (workspace->out_buf.pos >= max_out) {
153 tot_out += workspace->out_buf.pos;
154 ret = -E2BIG;
155 goto out;
156 }
157
158 /* Check if we need more output space */
159 if (workspace->out_buf.pos == workspace->out_buf.size) {
160 tot_out += PAGE_SIZE;
161 max_out -= PAGE_SIZE;
162 kunmap(out_page);
163 if (nr_pages == nr_dest_pages) {
164 out_page = NULL;
165 ret = -E2BIG;
166 goto out;
167 }
168 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
169 if (out_page == NULL) {
170 ret = -ENOMEM;
171 goto out;
172 }
173 pages[nr_pages++] = out_page;
174 workspace->out_buf.dst = kmap(out_page);
175 workspace->out_buf.pos = 0;
176 workspace->out_buf.size = min_t(size_t, max_out,
177 PAGE_SIZE);
178 }
179
180 /* We've reached the end of the input */
181 if (workspace->in_buf.pos >= len) {
182 tot_in += workspace->in_buf.pos;
183 break;
184 }
185
186 /* Check if we need more input */
187 if (workspace->in_buf.pos == workspace->in_buf.size) {
188 tot_in += PAGE_SIZE;
189 kunmap(in_page);
190 put_page(in_page);
191
192 start += PAGE_SIZE;
193 len -= PAGE_SIZE;
194 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
195 workspace->in_buf.src = kmap(in_page);
196 workspace->in_buf.pos = 0;
197 workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
198 }
199 }
200 while (1) {
201 size_t ret2;
202
203 ret2 = ZSTD_endStream(stream, &workspace->out_buf);
204 if (ZSTD_isError(ret2)) {
205 pr_debug("BTRFS: ZSTD_endStream returned %d\n",
206 ZSTD_getErrorCode(ret2));
207 ret = -EIO;
208 goto out;
209 }
210 if (ret2 == 0) {
211 tot_out += workspace->out_buf.pos;
212 break;
213 }
214 if (workspace->out_buf.pos >= max_out) {
215 tot_out += workspace->out_buf.pos;
216 ret = -E2BIG;
217 goto out;
218 }
219
220 tot_out += PAGE_SIZE;
221 max_out -= PAGE_SIZE;
222 kunmap(out_page);
223 if (nr_pages == nr_dest_pages) {
224 out_page = NULL;
225 ret = -E2BIG;
226 goto out;
227 }
228 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
229 if (out_page == NULL) {
230 ret = -ENOMEM;
231 goto out;
232 }
233 pages[nr_pages++] = out_page;
234 workspace->out_buf.dst = kmap(out_page);
235 workspace->out_buf.pos = 0;
236 workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
237 }
238
239 if (tot_out >= tot_in) {
240 ret = -E2BIG;
241 goto out;
242 }
243
244 ret = 0;
245 *total_in = tot_in;
246 *total_out = tot_out;
247out:
248 *out_pages = nr_pages;
249 /* Cleanup */
250 if (in_page) {
251 kunmap(in_page);
252 put_page(in_page);
253 }
254 if (out_page)
255 kunmap(out_page);
256 return ret;
257}
258
259static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
260{
261 struct workspace *workspace = list_entry(ws, struct workspace, list);
262 struct page **pages_in = cb->compressed_pages;
263 u64 disk_start = cb->start;
264 struct bio *orig_bio = cb->orig_bio;
265 size_t srclen = cb->compressed_len;
266 ZSTD_DStream *stream;
267 int ret = 0;
268 unsigned long page_in_index = 0;
269 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
270 unsigned long buf_start;
271 unsigned long total_out = 0;
272
273 stream = ZSTD_initDStream(
274 ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
275 if (!stream) {
276 pr_debug("BTRFS: ZSTD_initDStream failed\n");
277 ret = -EIO;
278 goto done;
279 }
280
281 workspace->in_buf.src = kmap(pages_in[page_in_index]);
282 workspace->in_buf.pos = 0;
283 workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
284
285 workspace->out_buf.dst = workspace->buf;
286 workspace->out_buf.pos = 0;
287 workspace->out_buf.size = PAGE_SIZE;
288
289 while (1) {
290 size_t ret2;
291
292 ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
293 &workspace->in_buf);
294 if (ZSTD_isError(ret2)) {
295 pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
296 ZSTD_getErrorCode(ret2));
297 ret = -EIO;
298 goto done;
299 }
300 buf_start = total_out;
301 total_out += workspace->out_buf.pos;
302 workspace->out_buf.pos = 0;
303
304 ret = btrfs_decompress_buf2page(workspace->out_buf.dst,
305 buf_start, total_out, disk_start, orig_bio);
306 if (ret == 0)
307 break;
308
309 if (workspace->in_buf.pos >= srclen)
310 break;
311
312 /* Check if we've hit the end of a frame */
313 if (ret2 == 0)
314 break;
315
316 if (workspace->in_buf.pos == workspace->in_buf.size) {
317 kunmap(pages_in[page_in_index++]);
318 if (page_in_index >= total_pages_in) {
319 workspace->in_buf.src = NULL;
320 ret = -EIO;
321 goto done;
322 }
323 srclen -= PAGE_SIZE;
324 workspace->in_buf.src = kmap(pages_in[page_in_index]);
325 workspace->in_buf.pos = 0;
326 workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
327 }
328 }
329 ret = 0;
330 zero_fill_bio(orig_bio);
331done:
332 if (workspace->in_buf.src)
333 kunmap(pages_in[page_in_index]);
334 return ret;
335}
336
337static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
338 struct page *dest_page,
339 unsigned long start_byte,
340 size_t srclen, size_t destlen)
341{
342 struct workspace *workspace = list_entry(ws, struct workspace, list);
343 ZSTD_DStream *stream;
344 int ret = 0;
345 size_t ret2;
346 unsigned long total_out = 0;
347 unsigned long pg_offset = 0;
348 char *kaddr;
349
350 stream = ZSTD_initDStream(
351 ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
352 if (!stream) {
353 pr_warn("BTRFS: ZSTD_initDStream failed\n");
354 ret = -EIO;
355 goto finish;
356 }
357
358 destlen = min_t(size_t, destlen, PAGE_SIZE);
359
360 workspace->in_buf.src = data_in;
361 workspace->in_buf.pos = 0;
362 workspace->in_buf.size = srclen;
363
364 workspace->out_buf.dst = workspace->buf;
365 workspace->out_buf.pos = 0;
366 workspace->out_buf.size = PAGE_SIZE;
367
368 ret2 = 1;
369 while (pg_offset < destlen
370 && workspace->in_buf.pos < workspace->in_buf.size) {
371 unsigned long buf_start;
372 unsigned long buf_offset;
373 unsigned long bytes;
374
375 /* Check if the frame is over and we still need more input */
376 if (ret2 == 0) {
377 pr_debug("BTRFS: ZSTD_decompressStream ended early\n");
378 ret = -EIO;
379 goto finish;
380 }
381 ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
382 &workspace->in_buf);
383 if (ZSTD_isError(ret2)) {
384 pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
385 ZSTD_getErrorCode(ret2));
386 ret = -EIO;
387 goto finish;
388 }
389
390 buf_start = total_out;
391 total_out += workspace->out_buf.pos;
392 workspace->out_buf.pos = 0;
393
394 if (total_out <= start_byte)
395 continue;
396
397 if (total_out > start_byte && buf_start < start_byte)
398 buf_offset = start_byte - buf_start;
399 else
400 buf_offset = 0;
401
402 bytes = min_t(unsigned long, destlen - pg_offset,
403 workspace->out_buf.size - buf_offset);
404
405 kaddr = kmap_atomic(dest_page);
406 memcpy(kaddr + pg_offset, workspace->out_buf.dst + buf_offset,
407 bytes);
408 kunmap_atomic(kaddr);
409
410 pg_offset += bytes;
411 }
412 ret = 0;
413finish:
414 if (pg_offset < destlen) {
415 kaddr = kmap_atomic(dest_page);
416 memset(kaddr + pg_offset, 0, destlen - pg_offset);
417 kunmap_atomic(kaddr);
418 }
419 return ret;
420}
421
422static void zstd_set_level(struct list_head *ws, unsigned int type)
423{
424}
425
426const struct btrfs_compress_op btrfs_zstd_compress = {
427 .alloc_workspace = zstd_alloc_workspace,
428 .free_workspace = zstd_free_workspace,
429 .compress_pages = zstd_compress_pages,
430 .decompress_bio = zstd_decompress_bio,
431 .decompress = zstd_decompress,
432 .set_level = zstd_set_level,
433};