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); 125 if (out_page == NULL) { 126 ret = -ENOMEM; 127 goto out; 128 } 129 cpage_out = page_address(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 put_page(in_page); 153 in_page = find_get_page(mapping, 154 start >> PAGE_SHIFT); 155 data_in = page_address(in_page); 156 memcpy(workspace->buf + i * PAGE_SIZE, 157 data_in, PAGE_SIZE); 158 start += PAGE_SIZE; 159 } 160 workspace->strm.next_in = workspace->buf; 161 } else { 162 if (in_page) 163 put_page(in_page); 164 in_page = find_get_page(mapping, 165 start >> PAGE_SHIFT); 166 data_in = page_address(in_page); 167 start += PAGE_SIZE; 168 workspace->strm.next_in = data_in; 169 } 170 workspace->strm.avail_in = min(bytes_left, 171 (unsigned long) workspace->buf_size); 172 } 173 174 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH); 175 if (ret != Z_OK) { 176 pr_debug("BTRFS: deflate in loop returned %d\n", 177 ret); 178 zlib_deflateEnd(&workspace->strm); 179 ret = -EIO; 180 goto out; 181 } 182 183 /* we're making it bigger, give up */ 184 if (workspace->strm.total_in > 8192 && 185 workspace->strm.total_in < 186 workspace->strm.total_out) { 187 ret = -E2BIG; 188 goto out; 189 } 190 /* we need another page for writing out. Test this 191 * before the total_in so we will pull in a new page for 192 * the stream end if required 193 */ 194 if (workspace->strm.avail_out == 0) { 195 if (nr_pages == nr_dest_pages) { 196 out_page = NULL; 197 ret = -E2BIG; 198 goto out; 199 } 200 out_page = alloc_page(GFP_NOFS); 201 if (out_page == NULL) { 202 ret = -ENOMEM; 203 goto out; 204 } 205 cpage_out = page_address(out_page); 206 pages[nr_pages] = out_page; 207 nr_pages++; 208 workspace->strm.avail_out = PAGE_SIZE; 209 workspace->strm.next_out = cpage_out; 210 } 211 /* we're all done */ 212 if (workspace->strm.total_in >= len) 213 break; 214 if (workspace->strm.total_out > max_out) 215 break; 216 } 217 workspace->strm.avail_in = 0; 218 /* 219 * Call deflate with Z_FINISH flush parameter providing more output 220 * space but no more input data, until it returns with Z_STREAM_END. 221 */ 222 while (ret != Z_STREAM_END) { 223 ret = zlib_deflate(&workspace->strm, Z_FINISH); 224 if (ret == Z_STREAM_END) 225 break; 226 if (ret != Z_OK && ret != Z_BUF_ERROR) { 227 zlib_deflateEnd(&workspace->strm); 228 ret = -EIO; 229 goto out; 230 } else if (workspace->strm.avail_out == 0) { 231 /* get another page for the stream end */ 232 if (nr_pages == nr_dest_pages) { 233 out_page = NULL; 234 ret = -E2BIG; 235 goto out; 236 } 237 out_page = alloc_page(GFP_NOFS); 238 if (out_page == NULL) { 239 ret = -ENOMEM; 240 goto out; 241 } 242 cpage_out = page_address(out_page); 243 pages[nr_pages] = out_page; 244 nr_pages++; 245 workspace->strm.avail_out = PAGE_SIZE; 246 workspace->strm.next_out = cpage_out; 247 } 248 } 249 zlib_deflateEnd(&workspace->strm); 250 251 if (workspace->strm.total_out >= workspace->strm.total_in) { 252 ret = -E2BIG; 253 goto out; 254 } 255 256 ret = 0; 257 *total_out = workspace->strm.total_out; 258 *total_in = workspace->strm.total_in; 259 out: 260 *out_pages = nr_pages; 261 if (in_page) 262 put_page(in_page); 263 return ret; 264 } 265 266 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 267 { 268 struct workspace *workspace = list_entry(ws, struct workspace, list); 269 int ret = 0, ret2; 270 int wbits = MAX_WBITS; 271 char *data_in; 272 size_t total_out = 0; 273 unsigned long page_in_index = 0; 274 size_t srclen = cb->compressed_len; 275 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); 276 unsigned long buf_start; 277 struct page **pages_in = cb->compressed_pages; 278 279 data_in = page_address(pages_in[page_in_index]); 280 workspace->strm.next_in = data_in; 281 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE); 282 workspace->strm.total_in = 0; 283 284 workspace->strm.total_out = 0; 285 workspace->strm.next_out = workspace->buf; 286 workspace->strm.avail_out = workspace->buf_size; 287 288 /* If it's deflate, and it's got no preset dictionary, then 289 we can tell zlib to skip the adler32 check. */ 290 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 291 ((data_in[0] & 0x0f) == Z_DEFLATED) && 292 !(((data_in[0]<<8) + data_in[1]) % 31)) { 293 294 wbits = -((data_in[0] >> 4) + 8); 295 workspace->strm.next_in += 2; 296 workspace->strm.avail_in -= 2; 297 } 298 299 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 300 pr_warn("BTRFS: inflateInit failed\n"); 301 return -EIO; 302 } 303 while (workspace->strm.total_in < srclen) { 304 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 305 if (ret != Z_OK && ret != Z_STREAM_END) 306 break; 307 308 buf_start = total_out; 309 total_out = workspace->strm.total_out; 310 311 /* we didn't make progress in this inflate call, we're done */ 312 if (buf_start == total_out) 313 break; 314 315 ret2 = btrfs_decompress_buf2page(workspace->buf, 316 total_out - buf_start, cb, buf_start); 317 if (ret2 == 0) { 318 ret = 0; 319 goto done; 320 } 321 322 workspace->strm.next_out = workspace->buf; 323 workspace->strm.avail_out = workspace->buf_size; 324 325 if (workspace->strm.avail_in == 0) { 326 unsigned long tmp; 327 328 page_in_index++; 329 if (page_in_index >= total_pages_in) { 330 data_in = NULL; 331 break; 332 } 333 data_in = page_address(pages_in[page_in_index]); 334 workspace->strm.next_in = data_in; 335 tmp = srclen - workspace->strm.total_in; 336 workspace->strm.avail_in = min(tmp, PAGE_SIZE); 337 } 338 } 339 if (ret != Z_STREAM_END) 340 ret = -EIO; 341 else 342 ret = 0; 343 done: 344 zlib_inflateEnd(&workspace->strm); 345 if (!ret) 346 zero_fill_bio(cb->orig_bio); 347 return ret; 348 } 349 350 int zlib_decompress(struct list_head *ws, unsigned char *data_in, 351 struct page *dest_page, unsigned long start_byte, size_t srclen, 352 size_t destlen) 353 { 354 struct workspace *workspace = list_entry(ws, struct workspace, list); 355 int ret = 0; 356 int wbits = MAX_WBITS; 357 unsigned long bytes_left; 358 unsigned long total_out = 0; 359 unsigned long pg_offset = 0; 360 361 destlen = min_t(unsigned long, destlen, PAGE_SIZE); 362 bytes_left = destlen; 363 364 workspace->strm.next_in = data_in; 365 workspace->strm.avail_in = srclen; 366 workspace->strm.total_in = 0; 367 368 workspace->strm.next_out = workspace->buf; 369 workspace->strm.avail_out = workspace->buf_size; 370 workspace->strm.total_out = 0; 371 /* If it's deflate, and it's got no preset dictionary, then 372 we can tell zlib to skip the adler32 check. */ 373 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 374 ((data_in[0] & 0x0f) == Z_DEFLATED) && 375 !(((data_in[0]<<8) + data_in[1]) % 31)) { 376 377 wbits = -((data_in[0] >> 4) + 8); 378 workspace->strm.next_in += 2; 379 workspace->strm.avail_in -= 2; 380 } 381 382 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 383 pr_warn("BTRFS: inflateInit failed\n"); 384 return -EIO; 385 } 386 387 while (bytes_left > 0) { 388 unsigned long buf_start; 389 unsigned long buf_offset; 390 unsigned long bytes; 391 392 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 393 if (ret != Z_OK && ret != Z_STREAM_END) 394 break; 395 396 buf_start = total_out; 397 total_out = workspace->strm.total_out; 398 399 if (total_out == buf_start) { 400 ret = -EIO; 401 break; 402 } 403 404 if (total_out <= start_byte) 405 goto next; 406 407 if (total_out > start_byte && buf_start < start_byte) 408 buf_offset = start_byte - buf_start; 409 else 410 buf_offset = 0; 411 412 bytes = min(PAGE_SIZE - pg_offset, 413 PAGE_SIZE - (buf_offset % PAGE_SIZE)); 414 bytes = min(bytes, bytes_left); 415 416 memcpy_to_page(dest_page, pg_offset, 417 workspace->buf + buf_offset, bytes); 418 419 pg_offset += bytes; 420 bytes_left -= bytes; 421 next: 422 workspace->strm.next_out = workspace->buf; 423 workspace->strm.avail_out = workspace->buf_size; 424 } 425 426 if (ret != Z_STREAM_END && bytes_left != 0) 427 ret = -EIO; 428 else 429 ret = 0; 430 431 zlib_inflateEnd(&workspace->strm); 432 433 /* 434 * this should only happen if zlib returned fewer bytes than we 435 * expected. btrfs_get_block is responsible for zeroing from the 436 * end of the inline extent (destlen) to the end of the page 437 */ 438 if (pg_offset < destlen) { 439 memzero_page(dest_page, pg_offset, destlen - pg_offset); 440 } 441 return ret; 442 } 443 444 const struct btrfs_compress_op btrfs_zlib_compress = { 445 .workspace_manager = &wsm, 446 .max_level = 9, 447 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL, 448 }; 449