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 }; 47 48 static 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 57 static 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; 78 fail: 79 zstd_free_workspace(&workspace->list); 80 return ERR_PTR(-ENOMEM); 81 } 82 83 static 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; /* The current page to read */ 96 struct page *out_page = NULL; /* The current page to write to */ 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 /* 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 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 /* 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 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 /* Check to see if we are making it bigger */ 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 /* We've reached the end of our output range */ 157 if (out_buf.pos >= max_out) { 158 tot_out += out_buf.pos; 159 ret = -E2BIG; 160 goto out; 161 } 162 163 /* Check if we need more output space */ 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 /* We've reached the end of the input */ 185 if (in_buf.pos >= len) { 186 tot_in += in_buf.pos; 187 break; 188 } 189 190 /* Check if we need more input */ 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; 251 out: 252 *out_pages = nr_pages; 253 /* Cleanup */ 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 } 262 263 static 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 /* Check if we've hit the end of a frame */ 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); 336 done: 337 if (in_buf.src) 338 kunmap(pages_in[page_in_index]); 339 return ret; 340 } 341 342 static 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 /* 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, &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; 417 finish: 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 } 425 426 const 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