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 = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN); 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 = NULL; 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 (data_in) { 152 kunmap_local(data_in); 153 put_page(in_page); 154 } 155 in_page = find_get_page(mapping, 156 start >> PAGE_SHIFT); 157 data_in = kmap_local_page(in_page); 158 copy_page(workspace->buf + i * PAGE_SIZE, 159 data_in); 160 start += PAGE_SIZE; 161 } 162 workspace->strm.next_in = workspace->buf; 163 } else { 164 if (data_in) { 165 kunmap_local(data_in); 166 put_page(in_page); 167 } 168 in_page = find_get_page(mapping, 169 start >> PAGE_SHIFT); 170 data_in = kmap_local_page(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 if (nr_pages == nr_dest_pages) { 200 ret = -E2BIG; 201 goto out; 202 } 203 out_page = alloc_page(GFP_NOFS); 204 if (out_page == NULL) { 205 ret = -ENOMEM; 206 goto out; 207 } 208 cpage_out = page_address(out_page); 209 pages[nr_pages] = out_page; 210 nr_pages++; 211 workspace->strm.avail_out = PAGE_SIZE; 212 workspace->strm.next_out = cpage_out; 213 } 214 /* we're all done */ 215 if (workspace->strm.total_in >= len) 216 break; 217 if (workspace->strm.total_out > max_out) 218 break; 219 } 220 workspace->strm.avail_in = 0; 221 /* 222 * Call deflate with Z_FINISH flush parameter providing more output 223 * space but no more input data, until it returns with Z_STREAM_END. 224 */ 225 while (ret != Z_STREAM_END) { 226 ret = zlib_deflate(&workspace->strm, Z_FINISH); 227 if (ret == Z_STREAM_END) 228 break; 229 if (ret != Z_OK && ret != Z_BUF_ERROR) { 230 zlib_deflateEnd(&workspace->strm); 231 ret = -EIO; 232 goto out; 233 } else if (workspace->strm.avail_out == 0) { 234 /* get another page for the stream end */ 235 if (nr_pages == nr_dest_pages) { 236 ret = -E2BIG; 237 goto out; 238 } 239 out_page = alloc_page(GFP_NOFS); 240 if (out_page == NULL) { 241 ret = -ENOMEM; 242 goto out; 243 } 244 cpage_out = page_address(out_page); 245 pages[nr_pages] = out_page; 246 nr_pages++; 247 workspace->strm.avail_out = PAGE_SIZE; 248 workspace->strm.next_out = cpage_out; 249 } 250 } 251 zlib_deflateEnd(&workspace->strm); 252 253 if (workspace->strm.total_out >= workspace->strm.total_in) { 254 ret = -E2BIG; 255 goto out; 256 } 257 258 ret = 0; 259 *total_out = workspace->strm.total_out; 260 *total_in = workspace->strm.total_in; 261 out: 262 *out_pages = nr_pages; 263 if (data_in) { 264 kunmap_local(data_in); 265 put_page(in_page); 266 } 267 268 return ret; 269 } 270 271 int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 272 { 273 struct workspace *workspace = list_entry(ws, struct workspace, list); 274 int ret = 0, ret2; 275 int wbits = MAX_WBITS; 276 char *data_in; 277 size_t total_out = 0; 278 unsigned long page_in_index = 0; 279 size_t srclen = cb->compressed_len; 280 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); 281 unsigned long buf_start; 282 struct page **pages_in = cb->compressed_pages; 283 284 data_in = kmap_local_page(pages_in[page_in_index]); 285 workspace->strm.next_in = data_in; 286 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE); 287 workspace->strm.total_in = 0; 288 289 workspace->strm.total_out = 0; 290 workspace->strm.next_out = workspace->buf; 291 workspace->strm.avail_out = workspace->buf_size; 292 293 /* If it's deflate, and it's got no preset dictionary, then 294 we can tell zlib to skip the adler32 check. */ 295 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 296 ((data_in[0] & 0x0f) == Z_DEFLATED) && 297 !(((data_in[0]<<8) + data_in[1]) % 31)) { 298 299 wbits = -((data_in[0] >> 4) + 8); 300 workspace->strm.next_in += 2; 301 workspace->strm.avail_in -= 2; 302 } 303 304 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 305 pr_warn("BTRFS: inflateInit failed\n"); 306 kunmap_local(data_in); 307 return -EIO; 308 } 309 while (workspace->strm.total_in < srclen) { 310 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 311 if (ret != Z_OK && ret != Z_STREAM_END) 312 break; 313 314 buf_start = total_out; 315 total_out = workspace->strm.total_out; 316 317 /* we didn't make progress in this inflate call, we're done */ 318 if (buf_start == total_out) 319 break; 320 321 ret2 = btrfs_decompress_buf2page(workspace->buf, 322 total_out - buf_start, cb, buf_start); 323 if (ret2 == 0) { 324 ret = 0; 325 goto done; 326 } 327 328 workspace->strm.next_out = workspace->buf; 329 workspace->strm.avail_out = workspace->buf_size; 330 331 if (workspace->strm.avail_in == 0) { 332 unsigned long tmp; 333 kunmap_local(data_in); 334 page_in_index++; 335 if (page_in_index >= total_pages_in) { 336 data_in = NULL; 337 break; 338 } 339 data_in = kmap_local_page(pages_in[page_in_index]); 340 workspace->strm.next_in = data_in; 341 tmp = srclen - workspace->strm.total_in; 342 workspace->strm.avail_in = min(tmp, PAGE_SIZE); 343 } 344 } 345 if (ret != Z_STREAM_END) 346 ret = -EIO; 347 else 348 ret = 0; 349 done: 350 zlib_inflateEnd(&workspace->strm); 351 if (data_in) 352 kunmap_local(data_in); 353 return ret; 354 } 355 356 int zlib_decompress(struct list_head *ws, const u8 *data_in, 357 struct page *dest_page, unsigned long start_byte, size_t srclen, 358 size_t destlen) 359 { 360 struct workspace *workspace = list_entry(ws, struct workspace, list); 361 int ret = 0; 362 int wbits = MAX_WBITS; 363 unsigned long bytes_left; 364 unsigned long total_out = 0; 365 unsigned long pg_offset = 0; 366 367 destlen = min_t(unsigned long, destlen, PAGE_SIZE); 368 bytes_left = destlen; 369 370 workspace->strm.next_in = data_in; 371 workspace->strm.avail_in = srclen; 372 workspace->strm.total_in = 0; 373 374 workspace->strm.next_out = workspace->buf; 375 workspace->strm.avail_out = workspace->buf_size; 376 workspace->strm.total_out = 0; 377 /* If it's deflate, and it's got no preset dictionary, then 378 we can tell zlib to skip the adler32 check. */ 379 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 380 ((data_in[0] & 0x0f) == Z_DEFLATED) && 381 !(((data_in[0]<<8) + data_in[1]) % 31)) { 382 383 wbits = -((data_in[0] >> 4) + 8); 384 workspace->strm.next_in += 2; 385 workspace->strm.avail_in -= 2; 386 } 387 388 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 389 pr_warn("BTRFS: inflateInit failed\n"); 390 return -EIO; 391 } 392 393 while (bytes_left > 0) { 394 unsigned long buf_start; 395 unsigned long buf_offset; 396 unsigned long bytes; 397 398 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 399 if (ret != Z_OK && ret != Z_STREAM_END) 400 break; 401 402 buf_start = total_out; 403 total_out = workspace->strm.total_out; 404 405 if (total_out == buf_start) { 406 ret = -EIO; 407 break; 408 } 409 410 if (total_out <= start_byte) 411 goto next; 412 413 if (total_out > start_byte && buf_start < start_byte) 414 buf_offset = start_byte - buf_start; 415 else 416 buf_offset = 0; 417 418 bytes = min(PAGE_SIZE - pg_offset, 419 PAGE_SIZE - (buf_offset % PAGE_SIZE)); 420 bytes = min(bytes, bytes_left); 421 422 memcpy_to_page(dest_page, pg_offset, 423 workspace->buf + buf_offset, bytes); 424 425 pg_offset += bytes; 426 bytes_left -= bytes; 427 next: 428 workspace->strm.next_out = workspace->buf; 429 workspace->strm.avail_out = workspace->buf_size; 430 } 431 432 if (ret != Z_STREAM_END && bytes_left != 0) 433 ret = -EIO; 434 else 435 ret = 0; 436 437 zlib_inflateEnd(&workspace->strm); 438 439 /* 440 * this should only happen if zlib returned fewer bytes than we 441 * expected. btrfs_get_block is responsible for zeroing from the 442 * end of the inline extent (destlen) to the end of the page 443 */ 444 if (pg_offset < destlen) { 445 memzero_page(dest_page, pg_offset, destlen - pg_offset); 446 } 447 return ret; 448 } 449 450 const struct btrfs_compress_op btrfs_zlib_compress = { 451 .workspace_manager = &wsm, 452 .max_level = 9, 453 .default_level = BTRFS_ZLIB_DEFAULT_LEVEL, 454 }; 455