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