1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2019 HUAWEI, Inc.
4 * https://www.huawei.com/
5 * Copyright (C) 2024 Alibaba Cloud
6 */
7 #include "compress.h"
8 #include <linux/lz4.h>
9
10 #ifndef LZ4_DISTANCE_MAX /* history window size */
11 #define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */
12 #endif
13
14 #define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
15 #ifndef LZ4_DECOMPRESS_INPLACE_MARGIN
16 #define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32)
17 #endif
18
19 struct z_erofs_lz4_decompress_ctx {
20 struct z_erofs_decompress_req *rq;
21 /* # of encoded, decoded pages */
22 unsigned int inpages, outpages;
23 /* decoded block total length (used for in-place decompression) */
24 unsigned int oend;
25 };
26
z_erofs_load_lz4_config(struct super_block * sb,struct erofs_super_block * dsb,void * data,int size)27 static int z_erofs_load_lz4_config(struct super_block *sb,
28 struct erofs_super_block *dsb, void *data, int size)
29 {
30 struct erofs_sb_info *sbi = EROFS_SB(sb);
31 struct z_erofs_lz4_cfgs *lz4 = data;
32 u16 distance;
33
34 if (lz4) {
35 if (size < sizeof(struct z_erofs_lz4_cfgs)) {
36 erofs_err(sb, "invalid lz4 cfgs, size=%u", size);
37 return -EINVAL;
38 }
39 distance = le16_to_cpu(lz4->max_distance);
40
41 sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks);
42 if (!sbi->lz4.max_pclusterblks) {
43 sbi->lz4.max_pclusterblks = 1; /* reserved case */
44 } else if (sbi->lz4.max_pclusterblks >
45 erofs_blknr(sb, Z_EROFS_PCLUSTER_MAX_SIZE)) {
46 erofs_err(sb, "too large lz4 pclusterblks %u",
47 sbi->lz4.max_pclusterblks);
48 return -EINVAL;
49 }
50 } else {
51 distance = le16_to_cpu(dsb->u1.lz4_max_distance);
52 sbi->lz4.max_pclusterblks = 1;
53 }
54
55 sbi->lz4.max_distance_pages = distance ?
56 DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :
57 LZ4_MAX_DISTANCE_PAGES;
58 return z_erofs_gbuf_growsize(sbi->lz4.max_pclusterblks);
59 }
60
61 /*
62 * Fill all gaps with bounce pages if it's a sparse page list. Also check if
63 * all physical pages are consecutive, which can be seen for moderate CR.
64 */
z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx * ctx,struct page ** pagepool)65 static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
66 struct page **pagepool)
67 {
68 struct z_erofs_decompress_req *rq = ctx->rq;
69 struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
70 unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
71 BITS_PER_LONG)] = { 0 };
72 unsigned int lz4_max_distance_pages =
73 EROFS_SB(rq->sb)->lz4.max_distance_pages;
74 void *kaddr = NULL;
75 unsigned int i, j, top;
76
77 top = 0;
78 for (i = j = 0; i < ctx->outpages; ++i, ++j) {
79 struct page *const page = rq->out[i];
80 struct page *victim;
81
82 if (j >= lz4_max_distance_pages)
83 j = 0;
84
85 /* 'valid' bounced can only be tested after a complete round */
86 if (!rq->fillgaps && test_bit(j, bounced)) {
87 DBG_BUGON(i < lz4_max_distance_pages);
88 DBG_BUGON(top >= lz4_max_distance_pages);
89 availables[top++] = rq->out[i - lz4_max_distance_pages];
90 }
91
92 if (page) {
93 __clear_bit(j, bounced);
94 if (!PageHighMem(page)) {
95 if (!i) {
96 kaddr = page_address(page);
97 continue;
98 }
99 if (kaddr &&
100 kaddr + PAGE_SIZE == page_address(page)) {
101 kaddr += PAGE_SIZE;
102 continue;
103 }
104 }
105 kaddr = NULL;
106 continue;
107 }
108 kaddr = NULL;
109 __set_bit(j, bounced);
110
111 if (top) {
112 victim = availables[--top];
113 } else {
114 victim = __erofs_allocpage(pagepool, rq->gfp, true);
115 if (!victim)
116 return -ENOMEM;
117 set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);
118 }
119 rq->out[i] = victim;
120 }
121 return kaddr ? 1 : 0;
122 }
123
z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx * ctx,void * inpage,void * out,unsigned int * inputmargin,int * maptype,bool may_inplace)124 static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
125 void *inpage, void *out, unsigned int *inputmargin,
126 int *maptype, bool may_inplace)
127 {
128 struct z_erofs_decompress_req *rq = ctx->rq;
129 unsigned int omargin, total, i;
130 struct page **in;
131 void *src, *tmp;
132
133 if (rq->inplace_io) {
134 omargin = PAGE_ALIGN(ctx->oend) - ctx->oend;
135 if (rq->partial_decoding || !may_inplace ||
136 omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize))
137 goto docopy;
138
139 for (i = 0; i < ctx->inpages; ++i)
140 if (rq->out[ctx->outpages - ctx->inpages + i] !=
141 rq->in[i])
142 goto docopy;
143 kunmap_local(inpage);
144 *maptype = 3;
145 return out + ((ctx->outpages - ctx->inpages) << PAGE_SHIFT);
146 }
147
148 if (ctx->inpages <= 1) {
149 *maptype = 0;
150 return inpage;
151 }
152 kunmap_local(inpage);
153 src = erofs_vm_map_ram(rq->in, ctx->inpages);
154 if (!src)
155 return ERR_PTR(-ENOMEM);
156 *maptype = 1;
157 return src;
158
159 docopy:
160 /* Or copy compressed data which can be overlapped to per-CPU buffer */
161 in = rq->in;
162 src = z_erofs_get_gbuf(ctx->inpages);
163 if (!src) {
164 DBG_BUGON(1);
165 kunmap_local(inpage);
166 return ERR_PTR(-EFAULT);
167 }
168
169 tmp = src;
170 total = rq->inputsize;
171 while (total) {
172 unsigned int page_copycnt =
173 min_t(unsigned int, total, PAGE_SIZE - *inputmargin);
174
175 if (!inpage)
176 inpage = kmap_local_page(*in);
177 memcpy(tmp, inpage + *inputmargin, page_copycnt);
178 kunmap_local(inpage);
179 inpage = NULL;
180 tmp += page_copycnt;
181 total -= page_copycnt;
182 ++in;
183 *inputmargin = 0;
184 }
185 *maptype = 2;
186 return src;
187 }
188
189 /*
190 * Get the exact inputsize with zero_padding feature.
191 * - For LZ4, it should work if zero_padding feature is on (5.3+);
192 * - For MicroLZMA, it'd be enabled all the time.
193 */
z_erofs_fixup_insize(struct z_erofs_decompress_req * rq,const char * padbuf,unsigned int padbufsize)194 int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
195 unsigned int padbufsize)
196 {
197 const char *padend;
198
199 padend = memchr_inv(padbuf, 0, padbufsize);
200 if (!padend)
201 return -EFSCORRUPTED;
202 rq->inputsize -= padend - padbuf;
203 rq->pageofs_in += padend - padbuf;
204 return 0;
205 }
206
z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx * ctx,u8 * dst)207 static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
208 u8 *dst)
209 {
210 struct z_erofs_decompress_req *rq = ctx->rq;
211 bool support_0padding = false, may_inplace = false;
212 unsigned int inputmargin;
213 u8 *out, *headpage, *src;
214 int ret, maptype;
215
216 DBG_BUGON(*rq->in == NULL);
217 headpage = kmap_local_page(*rq->in);
218
219 /* LZ4 decompression inplace is only safe if zero_padding is enabled */
220 if (erofs_sb_has_zero_padding(EROFS_SB(rq->sb))) {
221 support_0padding = true;
222 ret = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,
223 min_t(unsigned int, rq->inputsize,
224 rq->sb->s_blocksize - rq->pageofs_in));
225 if (ret) {
226 kunmap_local(headpage);
227 return ret;
228 }
229 may_inplace = !((rq->pageofs_in + rq->inputsize) &
230 (rq->sb->s_blocksize - 1));
231 }
232
233 inputmargin = rq->pageofs_in;
234 src = z_erofs_lz4_handle_overlap(ctx, headpage, dst, &inputmargin,
235 &maptype, may_inplace);
236 if (IS_ERR(src))
237 return PTR_ERR(src);
238
239 out = dst + rq->pageofs_out;
240 /* legacy format could compress extra data in a pcluster. */
241 if (rq->partial_decoding || !support_0padding)
242 ret = LZ4_decompress_safe_partial(src + inputmargin, out,
243 rq->inputsize, rq->outputsize, rq->outputsize);
244 else
245 ret = LZ4_decompress_safe(src + inputmargin, out,
246 rq->inputsize, rq->outputsize);
247
248 if (ret != rq->outputsize) {
249 erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
250 ret, rq->inputsize, inputmargin, rq->outputsize);
251 if (ret >= 0)
252 memset(out + ret, 0, rq->outputsize - ret);
253 ret = -EFSCORRUPTED;
254 } else {
255 ret = 0;
256 }
257
258 if (maptype == 0) {
259 kunmap_local(headpage);
260 } else if (maptype == 1) {
261 vm_unmap_ram(src, ctx->inpages);
262 } else if (maptype == 2) {
263 z_erofs_put_gbuf(src);
264 } else if (maptype != 3) {
265 DBG_BUGON(1);
266 return -EFAULT;
267 }
268 return ret;
269 }
270
z_erofs_lz4_decompress(struct z_erofs_decompress_req * rq,struct page ** pagepool)271 static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
272 struct page **pagepool)
273 {
274 struct z_erofs_lz4_decompress_ctx ctx;
275 unsigned int dst_maptype;
276 void *dst;
277 int ret;
278
279 ctx.rq = rq;
280 ctx.oend = rq->pageofs_out + rq->outputsize;
281 ctx.outpages = PAGE_ALIGN(ctx.oend) >> PAGE_SHIFT;
282 ctx.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
283
284 /* one optimized fast path only for non bigpcluster cases yet */
285 if (ctx.inpages == 1 && ctx.outpages == 1 && !rq->inplace_io) {
286 DBG_BUGON(!*rq->out);
287 dst = kmap_local_page(*rq->out);
288 dst_maptype = 0;
289 goto dstmap_out;
290 }
291
292 /* general decoding path which can be used for all cases */
293 ret = z_erofs_lz4_prepare_dstpages(&ctx, pagepool);
294 if (ret < 0) {
295 return ret;
296 } else if (ret > 0) {
297 dst = page_address(*rq->out);
298 dst_maptype = 1;
299 } else {
300 dst = erofs_vm_map_ram(rq->out, ctx.outpages);
301 if (!dst)
302 return -ENOMEM;
303 dst_maptype = 2;
304 }
305
306 dstmap_out:
307 ret = z_erofs_lz4_decompress_mem(&ctx, dst);
308 if (!dst_maptype)
309 kunmap_local(dst);
310 else if (dst_maptype == 2)
311 vm_unmap_ram(dst, ctx.outpages);
312 return ret;
313 }
314
z_erofs_transform_plain(struct z_erofs_decompress_req * rq,struct page ** pagepool)315 static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
316 struct page **pagepool)
317 {
318 const unsigned int nrpages_in =
319 PAGE_ALIGN(rq->pageofs_in + rq->inputsize) >> PAGE_SHIFT;
320 const unsigned int nrpages_out =
321 PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
322 const unsigned int bs = rq->sb->s_blocksize;
323 unsigned int cur = 0, ni = 0, no, pi, po, insz, cnt;
324 u8 *kin;
325
326 if (rq->outputsize > rq->inputsize)
327 return -EOPNOTSUPP;
328 if (rq->alg == Z_EROFS_COMPRESSION_INTERLACED) {
329 cur = bs - (rq->pageofs_out & (bs - 1));
330 pi = (rq->pageofs_in + rq->inputsize - cur) & ~PAGE_MASK;
331 cur = min(cur, rq->outputsize);
332 if (cur && rq->out[0]) {
333 kin = kmap_local_page(rq->in[nrpages_in - 1]);
334 if (rq->out[0] == rq->in[nrpages_in - 1])
335 memmove(kin + rq->pageofs_out, kin + pi, cur);
336 else
337 memcpy_to_page(rq->out[0], rq->pageofs_out,
338 kin + pi, cur);
339 kunmap_local(kin);
340 }
341 rq->outputsize -= cur;
342 }
343
344 for (; rq->outputsize; rq->pageofs_in = 0, cur += PAGE_SIZE, ni++) {
345 insz = min(PAGE_SIZE - rq->pageofs_in, rq->outputsize);
346 rq->outputsize -= insz;
347 if (!rq->in[ni])
348 continue;
349 kin = kmap_local_page(rq->in[ni]);
350 pi = 0;
351 do {
352 no = (rq->pageofs_out + cur + pi) >> PAGE_SHIFT;
353 po = (rq->pageofs_out + cur + pi) & ~PAGE_MASK;
354 DBG_BUGON(no >= nrpages_out);
355 cnt = min(insz - pi, PAGE_SIZE - po);
356 if (rq->out[no] == rq->in[ni])
357 memmove(kin + po,
358 kin + rq->pageofs_in + pi, cnt);
359 else if (rq->out[no])
360 memcpy_to_page(rq->out[no], po,
361 kin + rq->pageofs_in + pi, cnt);
362 pi += cnt;
363 } while (pi < insz);
364 kunmap_local(kin);
365 }
366 DBG_BUGON(ni > nrpages_in);
367 return 0;
368 }
369
z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx * dctx,void ** dst,void ** src,struct page ** pgpl)370 int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
371 void **src, struct page **pgpl)
372 {
373 struct z_erofs_decompress_req *rq = dctx->rq;
374 struct super_block *sb = rq->sb;
375 struct page **pgo, *tmppage;
376 unsigned int j;
377
378 if (!dctx->avail_out) {
379 if (++dctx->no >= dctx->outpages || !rq->outputsize) {
380 erofs_err(sb, "insufficient space for decompressed data");
381 return -EFSCORRUPTED;
382 }
383
384 if (dctx->kout)
385 kunmap_local(dctx->kout);
386 dctx->avail_out = min(rq->outputsize, PAGE_SIZE - rq->pageofs_out);
387 rq->outputsize -= dctx->avail_out;
388 pgo = &rq->out[dctx->no];
389 if (!*pgo && rq->fillgaps) { /* deduped */
390 *pgo = erofs_allocpage(pgpl, rq->gfp);
391 if (!*pgo) {
392 dctx->kout = NULL;
393 return -ENOMEM;
394 }
395 set_page_private(*pgo, Z_EROFS_SHORTLIVED_PAGE);
396 }
397 if (*pgo) {
398 dctx->kout = kmap_local_page(*pgo);
399 *dst = dctx->kout + rq->pageofs_out;
400 } else {
401 *dst = dctx->kout = NULL;
402 }
403 rq->pageofs_out = 0;
404 }
405
406 if (dctx->inbuf_pos == dctx->inbuf_sz && rq->inputsize) {
407 if (++dctx->ni >= dctx->inpages) {
408 erofs_err(sb, "invalid compressed data");
409 return -EFSCORRUPTED;
410 }
411 if (dctx->kout) /* unlike kmap(), take care of the orders */
412 kunmap_local(dctx->kout);
413 kunmap_local(dctx->kin);
414
415 dctx->inbuf_sz = min_t(u32, rq->inputsize, PAGE_SIZE);
416 rq->inputsize -= dctx->inbuf_sz;
417 dctx->kin = kmap_local_page(rq->in[dctx->ni]);
418 *src = dctx->kin;
419 dctx->bounced = false;
420 if (dctx->kout) {
421 j = (u8 *)*dst - dctx->kout;
422 dctx->kout = kmap_local_page(rq->out[dctx->no]);
423 *dst = dctx->kout + j;
424 }
425 dctx->inbuf_pos = 0;
426 }
427
428 /*
429 * Handle overlapping: Use the given bounce buffer if the input data is
430 * under processing; Or utilize short-lived pages from the on-stack page
431 * pool, where pages are shared among the same request. Note that only
432 * a few inplace I/O pages need to be doubled.
433 */
434 if (!dctx->bounced && rq->out[dctx->no] == rq->in[dctx->ni]) {
435 memcpy(dctx->bounce, *src, dctx->inbuf_sz);
436 *src = dctx->bounce;
437 dctx->bounced = true;
438 }
439
440 for (j = dctx->ni + 1; j < dctx->inpages; ++j) {
441 if (rq->out[dctx->no] != rq->in[j])
442 continue;
443 tmppage = erofs_allocpage(pgpl, rq->gfp);
444 if (!tmppage)
445 return -ENOMEM;
446 set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE);
447 copy_highpage(tmppage, rq->in[j]);
448 rq->in[j] = tmppage;
449 }
450 return 0;
451 }
452
453 const struct z_erofs_decompressor *z_erofs_decomp[] = {
454 [Z_EROFS_COMPRESSION_SHIFTED] = &(const struct z_erofs_decompressor) {
455 .decompress = z_erofs_transform_plain,
456 .name = "shifted"
457 },
458 [Z_EROFS_COMPRESSION_INTERLACED] = &(const struct z_erofs_decompressor) {
459 .decompress = z_erofs_transform_plain,
460 .name = "interlaced"
461 },
462 [Z_EROFS_COMPRESSION_LZ4] = &(const struct z_erofs_decompressor) {
463 .config = z_erofs_load_lz4_config,
464 .decompress = z_erofs_lz4_decompress,
465 .init = z_erofs_gbuf_init,
466 .exit = z_erofs_gbuf_exit,
467 .name = "lz4"
468 },
469 #ifdef CONFIG_EROFS_FS_ZIP_LZMA
470 [Z_EROFS_COMPRESSION_LZMA] = &z_erofs_lzma_decomp,
471 #endif
472 #ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
473 [Z_EROFS_COMPRESSION_DEFLATE] = &z_erofs_deflate_decomp,
474 #endif
475 #ifdef CONFIG_EROFS_FS_ZIP_ZSTD
476 [Z_EROFS_COMPRESSION_ZSTD] = &z_erofs_zstd_decomp,
477 #endif
478 };
479
z_erofs_parse_cfgs(struct super_block * sb,struct erofs_super_block * dsb)480 int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
481 {
482 struct erofs_sb_info *sbi = EROFS_SB(sb);
483 struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
484 unsigned int algs, alg;
485 erofs_off_t offset;
486 int size, ret = 0;
487
488 if (!erofs_sb_has_compr_cfgs(sbi)) {
489 sbi->available_compr_algs = 1 << Z_EROFS_COMPRESSION_LZ4;
490 return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
491 }
492
493 sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
494 if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
495 erofs_err(sb, "unidentified algorithms %x, please upgrade kernel",
496 sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
497 return -EOPNOTSUPP;
498 }
499
500 erofs_init_metabuf(&buf, sb);
501 offset = EROFS_SUPER_OFFSET + sbi->sb_size;
502 alg = 0;
503 for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
504 const struct z_erofs_decompressor *dec = z_erofs_decomp[alg];
505 void *data;
506
507 if (!(algs & 1))
508 continue;
509
510 data = erofs_read_metadata(sb, &buf, &offset, &size);
511 if (IS_ERR(data)) {
512 ret = PTR_ERR(data);
513 break;
514 }
515
516 if (alg < Z_EROFS_COMPRESSION_MAX && dec && dec->config) {
517 ret = dec->config(sb, dsb, data, size);
518 } else {
519 erofs_err(sb, "algorithm %d isn't enabled on this kernel",
520 alg);
521 ret = -EOPNOTSUPP;
522 }
523 kfree(data);
524 if (ret)
525 break;
526 }
527 erofs_put_metabuf(&buf);
528 return ret;
529 }
530
z_erofs_init_decompressor(void)531 int __init z_erofs_init_decompressor(void)
532 {
533 int i, err;
534
535 for (i = 0; i < Z_EROFS_COMPRESSION_MAX; ++i) {
536 err = z_erofs_decomp[i] ? z_erofs_decomp[i]->init() : 0;
537 if (err) {
538 while (i--)
539 if (z_erofs_decomp[i])
540 z_erofs_decomp[i]->exit();
541 return err;
542 }
543 }
544 return 0;
545 }
546
z_erofs_exit_decompressor(void)547 void z_erofs_exit_decompressor(void)
548 {
549 int i;
550
551 for (i = 0; i < Z_EROFS_COMPRESSION_MAX; ++i)
552 if (z_erofs_decomp[i])
553 z_erofs_decomp[i]->exit();
554 }
555