1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2008 Oracle. All rights reserved. 4 * 5 * Based on jffs2 zlib code: 6 * Copyright © 2001-2007 Red Hat, Inc. 7 * Created by David Woodhouse <dwmw2@infradead.org> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/slab.h> 12 #include <linux/zlib.h> 13 #include <linux/zutil.h> 14 #include <linux/mm.h> 15 #include <linux/init.h> 16 #include <linux/err.h> 17 #include <linux/sched.h> 18 #include <linux/pagemap.h> 19 #include <linux/bio.h> 20 #include <linux/refcount.h> 21 #include "compression.h" 22 23 /* workspace buffer size for s390 zlib hardware support */ 24 #define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE) 25 26 struct workspace { 27 z_stream strm; 28 char *buf; 29 unsigned int buf_size; 30 struct list_head list; 31 int level; 32 }; 33 34 static struct workspace_manager wsm; 35 36 struct list_head *zlib_get_workspace(unsigned int level) 37 { 38 struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level); 39 struct workspace *workspace = list_entry(ws, struct workspace, list); 40 41 workspace->level = level; 42 43 return ws; 44 } 45 46 void zlib_free_workspace(struct list_head *ws) 47 { 48 struct workspace *workspace = list_entry(ws, struct workspace, list); 49 50 kvfree(workspace->strm.workspace); 51 kfree(workspace->buf); 52 kfree(workspace); 53 } 54 55 struct list_head *zlib_alloc_workspace(unsigned int level) 56 { 57 struct workspace *workspace; 58 int workspacesize; 59 60 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); 61 if (!workspace) 62 return ERR_PTR(-ENOMEM); 63 64 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL), 65 zlib_inflate_workspacesize()); 66 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL); 67 workspace->level = level; 68 workspace->buf = NULL; 69 /* 70 * In case of s390 zlib hardware support, allocate lager workspace 71 * buffer. If allocator fails, fall back to a single page buffer. 72 */ 73 if (zlib_deflate_dfltcc_enabled()) { 74 workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE, 75 __GFP_NOMEMALLOC | __GFP_NORETRY | 76 __GFP_NOWARN | GFP_NOIO); 77 workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE; 78 } 79 if (!workspace->buf) { 80 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 81 workspace->buf_size = PAGE_SIZE; 82 } 83 if (!workspace->strm.workspace || !workspace->buf) 84 goto fail; 85 86 INIT_LIST_HEAD(&workspace->list); 87 88 return &workspace->list; 89 fail: 90 zlib_free_workspace(&workspace->list); 91 return ERR_PTR(-ENOMEM); 92 } 93 94 int zlib_compress_pages(struct list_head *ws, struct address_space *mapping, 95 u64 start, struct page **pages, unsigned long *out_pages, 96 unsigned long *total_in, unsigned long *total_out) 97 { 98 struct workspace *workspace = list_entry(ws, struct workspace, list); 99 int ret; 100 char *data_in; 101 char *cpage_out; 102 int nr_pages = 0; 103 struct page *in_page = NULL; 104 struct page *out_page = NULL; 105 unsigned long bytes_left; 106 unsigned int in_buf_pages; 107 unsigned long len = *total_out; 108 unsigned long nr_dest_pages = *out_pages; 109 const unsigned long max_out = nr_dest_pages * PAGE_SIZE; 110 111 *out_pages = 0; 112 *total_out = 0; 113 *total_in = 0; 114 115 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) { 116 pr_warn("BTRFS: deflateInit failed\n"); 117 ret = -EIO; 118 goto out; 119 } 120 121 workspace->strm.total_in = 0; 122 workspace->strm.total_out = 0; 123 124 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 125 if (out_page == NULL) { 126 ret = -ENOMEM; 127 goto out; 128 } 129 cpage_out = kmap(out_page); 130 pages[0] = out_page; 131 nr_pages = 1; 132 133 workspace->strm.next_in = workspace->buf; 134 workspace->strm.avail_in = 0; 135 workspace->strm.next_out = cpage_out; 136 workspace->strm.avail_out = PAGE_SIZE; 137 138 while (workspace->strm.total_in < len) { 139 /* 140 * Get next input pages and copy the contents to 141 * the workspace buffer if required. 142 */ 143 if (workspace->strm.avail_in == 0) { 144 bytes_left = len - workspace->strm.total_in; 145 in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE), 146 workspace->buf_size / PAGE_SIZE); 147 if (in_buf_pages > 1) { 148 int i; 149 150 for (i = 0; i < in_buf_pages; i++) { 151 if (in_page) { 152 kunmap(in_page); 153 put_page(in_page); 154 } 155 in_page = find_get_page(mapping, 156 start >> PAGE_SHIFT); 157 data_in = kmap(in_page); 158 memcpy(workspace->buf + i * PAGE_SIZE, 159 data_in, PAGE_SIZE); 160 start += PAGE_SIZE; 161 } 162 workspace->strm.next_in = workspace->buf; 163 } else { 164 if (in_page) { 165 kunmap(in_page); 166 put_page(in_page); 167 } 168 in_page = find_get_page(mapping, 169 start >> PAGE_SHIFT); 170 data_in = kmap(in_page); 171 start += PAGE_SIZE; 172 workspace->strm.next_in = data_in; 173 } 174 workspace->strm.avail_in = min(bytes_left, 175 (unsigned long) workspace->buf_size); 176 } 177 178 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH); 179 if (ret != Z_OK) { 180 pr_debug("BTRFS: deflate in loop returned %d\n", 181 ret); 182 zlib_deflateEnd(&workspace->strm); 183 ret = -EIO; 184 goto out; 185 } 186 187 /* we're making it bigger, give up */ 188 if (workspace->strm.total_in > 8192 && 189 workspace->strm.total_in < 190 workspace->strm.total_out) { 191 ret = -E2BIG; 192 goto out; 193 } 194 /* we need another page for writing out. Test this 195 * before the total_in so we will pull in a new page for 196 * the stream end if required 197 */ 198 if (workspace->strm.avail_out == 0) { 199 kunmap(out_page); 200 if (nr_pages == nr_dest_pages) { 201 out_page = NULL; 202 ret = -E2BIG; 203 goto out; 204 } 205 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 206 if (out_page == NULL) { 207 ret = -ENOMEM; 208 goto out; 209 } 210 cpage_out = kmap(out_page); 211 pages[nr_pages] = out_page; 212 nr_pages++; 213 workspace->strm.avail_out = PAGE_SIZE; 214 workspace->strm.next_out = cpage_out; 215 } 216 /* we're all done */ 217 if (workspace->strm.total_in >= len) 218 break; 219 if (workspace->strm.total_out > max_out) 220 break; 221 } 222 workspace->strm.avail_in = 0; 223 /* 224 * Call deflate with Z_FINISH flush parameter providing more output 225 * space but no more input data, until it returns with Z_STREAM_END. 226 */ 227 while (ret != Z_STREAM_END) { 228 ret = zlib_deflate(&workspace->strm, Z_FINISH); 229 if (ret == Z_STREAM_END) 230 break; 231 if (ret != Z_OK && ret != Z_BUF_ERROR) { 232 zlib_deflateEnd(&workspace->strm); 233 ret = -EIO; 234 goto out; 235 } else if (workspace->strm.avail_out == 0) { 236 /* get another page for the stream end */ 237 kunmap(out_page); 238 if (nr_pages == nr_dest_pages) { 239 out_page = NULL; 240 ret = -E2BIG; 241 goto out; 242 } 243 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 244 if (out_page == NULL) { 245 ret = -ENOMEM; 246 goto out; 247 } 248 cpage_out = kmap(out_page); 249 pages[nr_pages] = out_page; 250 nr_pages++; 251 workspace->strm.avail_out = PAGE_SIZE; 252 workspace->strm.next_out = cpage_out; 253 } 254 } 255 zlib_deflateEnd(&workspace->strm); 256 257 if (workspace->strm.total_out >= workspace->strm.total_in) { 258 ret = -E2BIG; 259 goto out; 260 } 261 262 ret = 0; 263 *total_out = workspace->strm.total_out; 264 *total_in = workspace->strm.total_in; 265 out: 266 *out_pages = nr_pages; 267 if (out_page) 268 kunmap(out_page); 269 270 if (in_page) { 271 kunmap(in_page); 272 put_page(in_page); 273 } 274 return ret; 275 } 276 277 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 278 { 279 struct workspace *workspace = list_entry(ws, struct workspace, list); 280 int ret = 0, ret2; 281 int wbits = MAX_WBITS; 282 char *data_in; 283 size_t total_out = 0; 284 unsigned long page_in_index = 0; 285 size_t srclen = cb->compressed_len; 286 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); 287 unsigned long buf_start; 288 struct page **pages_in = cb->compressed_pages; 289 u64 disk_start = cb->start; 290 struct bio *orig_bio = cb->orig_bio; 291 292 data_in = kmap(pages_in[page_in_index]); 293 workspace->strm.next_in = data_in; 294 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE); 295 workspace->strm.total_in = 0; 296 297 workspace->strm.total_out = 0; 298 workspace->strm.next_out = workspace->buf; 299 workspace->strm.avail_out = workspace->buf_size; 300 301 /* If it's deflate, and it's got no preset dictionary, then 302 we can tell zlib to skip the adler32 check. */ 303 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 304 ((data_in[0] & 0x0f) == Z_DEFLATED) && 305 !(((data_in[0]<<8) + data_in[1]) % 31)) { 306 307 wbits = -((data_in[0] >> 4) + 8); 308 workspace->strm.next_in += 2; 309 workspace->strm.avail_in -= 2; 310 } 311 312 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 313 pr_warn("BTRFS: inflateInit failed\n"); 314 kunmap(pages_in[page_in_index]); 315 return -EIO; 316 } 317 while (workspace->strm.total_in < srclen) { 318 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 319 if (ret != Z_OK && ret != Z_STREAM_END) 320 break; 321 322 buf_start = total_out; 323 total_out = workspace->strm.total_out; 324 325 /* we didn't make progress in this inflate call, we're done */ 326 if (buf_start == total_out) 327 break; 328 329 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, 330 total_out, disk_start, 331 orig_bio); 332 if (ret2 == 0) { 333 ret = 0; 334 goto done; 335 } 336 337 workspace->strm.next_out = workspace->buf; 338 workspace->strm.avail_out = workspace->buf_size; 339 340 if (workspace->strm.avail_in == 0) { 341 unsigned long tmp; 342 kunmap(pages_in[page_in_index]); 343 page_in_index++; 344 if (page_in_index >= total_pages_in) { 345 data_in = NULL; 346 break; 347 } 348 data_in = kmap(pages_in[page_in_index]); 349 workspace->strm.next_in = data_in; 350 tmp = srclen - workspace->strm.total_in; 351 workspace->strm.avail_in = min(tmp, 352 PAGE_SIZE); 353 } 354 } 355 if (ret != Z_STREAM_END) 356 ret = -EIO; 357 else 358 ret = 0; 359 done: 360 zlib_inflateEnd(&workspace->strm); 361 if (data_in) 362 kunmap(pages_in[page_in_index]); 363 if (!ret) 364 zero_fill_bio(orig_bio); 365 return ret; 366 } 367 368 int zlib_decompress(struct list_head *ws, unsigned char *data_in, 369 struct page *dest_page, unsigned long start_byte, size_t srclen, 370 size_t destlen) 371 { 372 struct workspace *workspace = list_entry(ws, struct workspace, list); 373 int ret = 0; 374 int wbits = MAX_WBITS; 375 unsigned long bytes_left; 376 unsigned long total_out = 0; 377 unsigned long pg_offset = 0; 378 char *kaddr; 379 380 destlen = min_t(unsigned long, destlen, PAGE_SIZE); 381 bytes_left = destlen; 382 383 workspace->strm.next_in = data_in; 384 workspace->strm.avail_in = srclen; 385 workspace->strm.total_in = 0; 386 387 workspace->strm.next_out = workspace->buf; 388 workspace->strm.avail_out = workspace->buf_size; 389 workspace->strm.total_out = 0; 390 /* If it's deflate, and it's got no preset dictionary, then 391 we can tell zlib to skip the adler32 check. */ 392 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 393 ((data_in[0] & 0x0f) == Z_DEFLATED) && 394 !(((data_in[0]<<8) + data_in[1]) % 31)) { 395 396 wbits = -((data_in[0] >> 4) + 8); 397 workspace->strm.next_in += 2; 398 workspace->strm.avail_in -= 2; 399 } 400 401 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 402 pr_warn("BTRFS: inflateInit failed\n"); 403 return -EIO; 404 } 405 406 while (bytes_left > 0) { 407 unsigned long buf_start; 408 unsigned long buf_offset; 409 unsigned long bytes; 410 411 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 412 if (ret != Z_OK && ret != Z_STREAM_END) 413 break; 414 415 buf_start = total_out; 416 total_out = workspace->strm.total_out; 417 418 if (total_out == buf_start) { 419 ret = -EIO; 420 break; 421 } 422 423 if (total_out <= start_byte) 424 goto next; 425 426 if (total_out > start_byte && buf_start < start_byte) 427 buf_offset = start_byte - buf_start; 428 else 429 buf_offset = 0; 430 431 bytes = min(PAGE_SIZE - pg_offset, 432 PAGE_SIZE - (buf_offset % PAGE_SIZE)); 433 bytes = min(bytes, bytes_left); 434 435 kaddr = kmap_atomic(dest_page); 436 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes); 437 kunmap_atomic(kaddr); 438 439 pg_offset += bytes; 440 bytes_left -= bytes; 441 next: 442 workspace->strm.next_out = workspace->buf; 443 workspace->strm.avail_out = workspace->buf_size; 444 } 445 446 if (ret != Z_STREAM_END && bytes_left != 0) 447 ret = -EIO; 448 else 449 ret = 0; 450 451 zlib_inflateEnd(&workspace->strm); 452 453 /* 454 * this should only happen if zlib returned fewer bytes than we 455 * expected. btrfs_get_block is responsible for zeroing from the 456 * end of the inline extent (destlen) to the end of the page 457 */ 458 if (pg_offset < destlen) { 459 kaddr = kmap_atomic(dest_page); 460 memset(kaddr + pg_offset, 0, destlen - pg_offset); 461 kunmap_atomic(kaddr); 462 } 463 return ret; 464 } 465 466 const struct btrfs_compress_op btrfs_zlib_compress = { 467 .workspace_manager = &wsm, 468 .max_level = 9, 469 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL, 470 }; 471