1 /* 2 * Copyright (c) 2016-present, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public 7 * License v2 as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 * General Public License for more details. 13 */ 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 30 static 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 41 struct workspace { 42 void *mem; 43 size_t size; 44 char *buf; 45 struct list_head list; 46 ZSTD_inBuffer in_buf; 47 ZSTD_outBuffer out_buf; 48 }; 49 50 static void zstd_free_workspace(struct list_head *ws) 51 { 52 struct workspace *workspace = list_entry(ws, struct workspace, list); 53 54 kvfree(workspace->mem); 55 kfree(workspace->buf); 56 kfree(workspace); 57 } 58 59 static struct list_head *zstd_alloc_workspace(void) 60 { 61 ZSTD_parameters params = 62 zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT); 63 struct workspace *workspace; 64 65 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); 66 if (!workspace) 67 return ERR_PTR(-ENOMEM); 68 69 workspace->size = max_t(size_t, 70 ZSTD_CStreamWorkspaceBound(params.cParams), 71 ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT)); 72 workspace->mem = kvmalloc(workspace->size, GFP_KERNEL); 73 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 74 if (!workspace->mem || !workspace->buf) 75 goto fail; 76 77 INIT_LIST_HEAD(&workspace->list); 78 79 return &workspace->list; 80 fail: 81 zstd_free_workspace(&workspace->list); 82 return ERR_PTR(-ENOMEM); 83 } 84 85 static int zstd_compress_pages(struct list_head *ws, 86 struct address_space *mapping, 87 u64 start, 88 struct page **pages, 89 unsigned long *out_pages, 90 unsigned long *total_in, 91 unsigned long *total_out) 92 { 93 struct workspace *workspace = list_entry(ws, struct workspace, list); 94 ZSTD_CStream *stream; 95 int ret = 0; 96 int nr_pages = 0; 97 struct page *in_page = NULL; /* The current page to read */ 98 struct page *out_page = NULL; /* The current page to write to */ 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 /* Initialize the stream */ 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 /* map in the first page of input data */ 120 in_page = find_get_page(mapping, start >> PAGE_SHIFT); 121 workspace->in_buf.src = kmap(in_page); 122 workspace->in_buf.pos = 0; 123 workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE); 124 125 126 /* Allocate and map in the output buffer */ 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 workspace->out_buf.dst = kmap(out_page); 134 workspace->out_buf.pos = 0; 135 workspace->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, &workspace->out_buf, 141 &workspace->in_buf); 142 if (ZSTD_isError(ret2)) { 143 pr_debug("BTRFS: ZSTD_compressStream returned %d\n", 144 ZSTD_getErrorCode(ret2)); 145 ret = -EIO; 146 goto out; 147 } 148 149 /* Check to see if we are making it bigger */ 150 if (tot_in + workspace->in_buf.pos > 8192 && 151 tot_in + workspace->in_buf.pos < 152 tot_out + workspace->out_buf.pos) { 153 ret = -E2BIG; 154 goto out; 155 } 156 157 /* We've reached the end of our output range */ 158 if (workspace->out_buf.pos >= max_out) { 159 tot_out += workspace->out_buf.pos; 160 ret = -E2BIG; 161 goto out; 162 } 163 164 /* Check if we need more output space */ 165 if (workspace->out_buf.pos == workspace->out_buf.size) { 166 tot_out += PAGE_SIZE; 167 max_out -= PAGE_SIZE; 168 kunmap(out_page); 169 if (nr_pages == nr_dest_pages) { 170 out_page = NULL; 171 ret = -E2BIG; 172 goto out; 173 } 174 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 175 if (out_page == NULL) { 176 ret = -ENOMEM; 177 goto out; 178 } 179 pages[nr_pages++] = out_page; 180 workspace->out_buf.dst = kmap(out_page); 181 workspace->out_buf.pos = 0; 182 workspace->out_buf.size = min_t(size_t, max_out, 183 PAGE_SIZE); 184 } 185 186 /* We've reached the end of the input */ 187 if (workspace->in_buf.pos >= len) { 188 tot_in += workspace->in_buf.pos; 189 break; 190 } 191 192 /* Check if we need more input */ 193 if (workspace->in_buf.pos == workspace->in_buf.size) { 194 tot_in += PAGE_SIZE; 195 kunmap(in_page); 196 put_page(in_page); 197 198 start += PAGE_SIZE; 199 len -= PAGE_SIZE; 200 in_page = find_get_page(mapping, start >> PAGE_SHIFT); 201 workspace->in_buf.src = kmap(in_page); 202 workspace->in_buf.pos = 0; 203 workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE); 204 } 205 } 206 while (1) { 207 size_t ret2; 208 209 ret2 = ZSTD_endStream(stream, &workspace->out_buf); 210 if (ZSTD_isError(ret2)) { 211 pr_debug("BTRFS: ZSTD_endStream returned %d\n", 212 ZSTD_getErrorCode(ret2)); 213 ret = -EIO; 214 goto out; 215 } 216 if (ret2 == 0) { 217 tot_out += workspace->out_buf.pos; 218 break; 219 } 220 if (workspace->out_buf.pos >= max_out) { 221 tot_out += workspace->out_buf.pos; 222 ret = -E2BIG; 223 goto out; 224 } 225 226 tot_out += PAGE_SIZE; 227 max_out -= PAGE_SIZE; 228 kunmap(out_page); 229 if (nr_pages == nr_dest_pages) { 230 out_page = NULL; 231 ret = -E2BIG; 232 goto out; 233 } 234 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 235 if (out_page == NULL) { 236 ret = -ENOMEM; 237 goto out; 238 } 239 pages[nr_pages++] = out_page; 240 workspace->out_buf.dst = kmap(out_page); 241 workspace->out_buf.pos = 0; 242 workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE); 243 } 244 245 if (tot_out >= tot_in) { 246 ret = -E2BIG; 247 goto out; 248 } 249 250 ret = 0; 251 *total_in = tot_in; 252 *total_out = tot_out; 253 out: 254 *out_pages = nr_pages; 255 /* Cleanup */ 256 if (in_page) { 257 kunmap(in_page); 258 put_page(in_page); 259 } 260 if (out_page) 261 kunmap(out_page); 262 return ret; 263 } 264 265 static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 266 { 267 struct workspace *workspace = list_entry(ws, struct workspace, list); 268 struct page **pages_in = cb->compressed_pages; 269 u64 disk_start = cb->start; 270 struct bio *orig_bio = cb->orig_bio; 271 size_t srclen = cb->compressed_len; 272 ZSTD_DStream *stream; 273 int ret = 0; 274 unsigned long page_in_index = 0; 275 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); 276 unsigned long buf_start; 277 unsigned long total_out = 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 workspace->in_buf.src = kmap(pages_in[page_in_index]); 288 workspace->in_buf.pos = 0; 289 workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE); 290 291 workspace->out_buf.dst = workspace->buf; 292 workspace->out_buf.pos = 0; 293 workspace->out_buf.size = PAGE_SIZE; 294 295 while (1) { 296 size_t ret2; 297 298 ret2 = ZSTD_decompressStream(stream, &workspace->out_buf, 299 &workspace->in_buf); 300 if (ZSTD_isError(ret2)) { 301 pr_debug("BTRFS: ZSTD_decompressStream returned %d\n", 302 ZSTD_getErrorCode(ret2)); 303 ret = -EIO; 304 goto done; 305 } 306 buf_start = total_out; 307 total_out += workspace->out_buf.pos; 308 workspace->out_buf.pos = 0; 309 310 ret = btrfs_decompress_buf2page(workspace->out_buf.dst, 311 buf_start, total_out, disk_start, orig_bio); 312 if (ret == 0) 313 break; 314 315 if (workspace->in_buf.pos >= srclen) 316 break; 317 318 /* Check if we've hit the end of a frame */ 319 if (ret2 == 0) 320 break; 321 322 if (workspace->in_buf.pos == workspace->in_buf.size) { 323 kunmap(pages_in[page_in_index++]); 324 if (page_in_index >= total_pages_in) { 325 workspace->in_buf.src = NULL; 326 ret = -EIO; 327 goto done; 328 } 329 srclen -= PAGE_SIZE; 330 workspace->in_buf.src = kmap(pages_in[page_in_index]); 331 workspace->in_buf.pos = 0; 332 workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE); 333 } 334 } 335 ret = 0; 336 zero_fill_bio(orig_bio); 337 done: 338 if (workspace->in_buf.src) 339 kunmap(pages_in[page_in_index]); 340 return ret; 341 } 342 343 static int zstd_decompress(struct list_head *ws, unsigned char *data_in, 344 struct page *dest_page, 345 unsigned long start_byte, 346 size_t srclen, size_t destlen) 347 { 348 struct workspace *workspace = list_entry(ws, struct workspace, list); 349 ZSTD_DStream *stream; 350 int ret = 0; 351 size_t ret2; 352 unsigned long total_out = 0; 353 unsigned long pg_offset = 0; 354 char *kaddr; 355 356 stream = ZSTD_initDStream( 357 ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size); 358 if (!stream) { 359 pr_warn("BTRFS: ZSTD_initDStream failed\n"); 360 ret = -EIO; 361 goto finish; 362 } 363 364 destlen = min_t(size_t, destlen, PAGE_SIZE); 365 366 workspace->in_buf.src = data_in; 367 workspace->in_buf.pos = 0; 368 workspace->in_buf.size = srclen; 369 370 workspace->out_buf.dst = workspace->buf; 371 workspace->out_buf.pos = 0; 372 workspace->out_buf.size = PAGE_SIZE; 373 374 ret2 = 1; 375 while (pg_offset < destlen 376 && workspace->in_buf.pos < workspace->in_buf.size) { 377 unsigned long buf_start; 378 unsigned long buf_offset; 379 unsigned long bytes; 380 381 /* Check if the frame is over and we still need more input */ 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, &workspace->out_buf, 388 &workspace->in_buf); 389 if (ZSTD_isError(ret2)) { 390 pr_debug("BTRFS: ZSTD_decompressStream returned %d\n", 391 ZSTD_getErrorCode(ret2)); 392 ret = -EIO; 393 goto finish; 394 } 395 396 buf_start = total_out; 397 total_out += workspace->out_buf.pos; 398 workspace->out_buf.pos = 0; 399 400 if (total_out <= start_byte) 401 continue; 402 403 if (total_out > start_byte && buf_start < start_byte) 404 buf_offset = start_byte - buf_start; 405 else 406 buf_offset = 0; 407 408 bytes = min_t(unsigned long, destlen - pg_offset, 409 workspace->out_buf.size - buf_offset); 410 411 kaddr = kmap_atomic(dest_page); 412 memcpy(kaddr + pg_offset, workspace->out_buf.dst + buf_offset, 413 bytes); 414 kunmap_atomic(kaddr); 415 416 pg_offset += bytes; 417 } 418 ret = 0; 419 finish: 420 if (pg_offset < destlen) { 421 kaddr = kmap_atomic(dest_page); 422 memset(kaddr + pg_offset, 0, destlen - pg_offset); 423 kunmap_atomic(kaddr); 424 } 425 return ret; 426 } 427 428 static void zstd_set_level(struct list_head *ws, unsigned int type) 429 { 430 } 431 432 const struct btrfs_compress_op btrfs_zstd_compress = { 433 .alloc_workspace = zstd_alloc_workspace, 434 .free_workspace = zstd_free_workspace, 435 .compress_pages = zstd_compress_pages, 436 .decompress_bio = zstd_decompress_bio, 437 .decompress = zstd_decompress, 438 .set_level = zstd_set_level, 439 }; 440