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 struct workspace { 24 z_stream strm; 25 char *buf; 26 struct list_head list; 27 int level; 28 }; 29 30 static void zlib_free_workspace(struct list_head *ws) 31 { 32 struct workspace *workspace = list_entry(ws, struct workspace, list); 33 34 kvfree(workspace->strm.workspace); 35 kfree(workspace->buf); 36 kfree(workspace); 37 } 38 39 static struct list_head *zlib_alloc_workspace(void) 40 { 41 struct workspace *workspace; 42 int workspacesize; 43 44 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); 45 if (!workspace) 46 return ERR_PTR(-ENOMEM); 47 48 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL), 49 zlib_inflate_workspacesize()); 50 workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL); 51 workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); 52 if (!workspace->strm.workspace || !workspace->buf) 53 goto fail; 54 55 INIT_LIST_HEAD(&workspace->list); 56 57 return &workspace->list; 58 fail: 59 zlib_free_workspace(&workspace->list); 60 return ERR_PTR(-ENOMEM); 61 } 62 63 static int zlib_compress_pages(struct list_head *ws, 64 struct address_space *mapping, 65 u64 start, 66 struct page **pages, 67 unsigned long *out_pages, 68 unsigned long *total_in, 69 unsigned long *total_out) 70 { 71 struct workspace *workspace = list_entry(ws, struct workspace, list); 72 int ret; 73 char *data_in; 74 char *cpage_out; 75 int nr_pages = 0; 76 struct page *in_page = NULL; 77 struct page *out_page = NULL; 78 unsigned long bytes_left; 79 unsigned long len = *total_out; 80 unsigned long nr_dest_pages = *out_pages; 81 const unsigned long max_out = nr_dest_pages * PAGE_SIZE; 82 83 *out_pages = 0; 84 *total_out = 0; 85 *total_in = 0; 86 87 if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) { 88 pr_warn("BTRFS: deflateInit failed\n"); 89 ret = -EIO; 90 goto out; 91 } 92 93 workspace->strm.total_in = 0; 94 workspace->strm.total_out = 0; 95 96 in_page = find_get_page(mapping, start >> PAGE_SHIFT); 97 data_in = kmap(in_page); 98 99 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 100 if (out_page == NULL) { 101 ret = -ENOMEM; 102 goto out; 103 } 104 cpage_out = kmap(out_page); 105 pages[0] = out_page; 106 nr_pages = 1; 107 108 workspace->strm.next_in = data_in; 109 workspace->strm.next_out = cpage_out; 110 workspace->strm.avail_out = PAGE_SIZE; 111 workspace->strm.avail_in = min(len, PAGE_SIZE); 112 113 while (workspace->strm.total_in < len) { 114 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH); 115 if (ret != Z_OK) { 116 pr_debug("BTRFS: deflate in loop returned %d\n", 117 ret); 118 zlib_deflateEnd(&workspace->strm); 119 ret = -EIO; 120 goto out; 121 } 122 123 /* we're making it bigger, give up */ 124 if (workspace->strm.total_in > 8192 && 125 workspace->strm.total_in < 126 workspace->strm.total_out) { 127 ret = -E2BIG; 128 goto out; 129 } 130 /* we need another page for writing out. Test this 131 * before the total_in so we will pull in a new page for 132 * the stream end if required 133 */ 134 if (workspace->strm.avail_out == 0) { 135 kunmap(out_page); 136 if (nr_pages == nr_dest_pages) { 137 out_page = NULL; 138 ret = -E2BIG; 139 goto out; 140 } 141 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 142 if (out_page == NULL) { 143 ret = -ENOMEM; 144 goto out; 145 } 146 cpage_out = kmap(out_page); 147 pages[nr_pages] = out_page; 148 nr_pages++; 149 workspace->strm.avail_out = PAGE_SIZE; 150 workspace->strm.next_out = cpage_out; 151 } 152 /* we're all done */ 153 if (workspace->strm.total_in >= len) 154 break; 155 156 /* we've read in a full page, get a new one */ 157 if (workspace->strm.avail_in == 0) { 158 if (workspace->strm.total_out > max_out) 159 break; 160 161 bytes_left = len - workspace->strm.total_in; 162 kunmap(in_page); 163 put_page(in_page); 164 165 start += PAGE_SIZE; 166 in_page = find_get_page(mapping, 167 start >> PAGE_SHIFT); 168 data_in = kmap(in_page); 169 workspace->strm.avail_in = min(bytes_left, 170 PAGE_SIZE); 171 workspace->strm.next_in = data_in; 172 } 173 } 174 workspace->strm.avail_in = 0; 175 ret = zlib_deflate(&workspace->strm, Z_FINISH); 176 zlib_deflateEnd(&workspace->strm); 177 178 if (ret != Z_STREAM_END) { 179 ret = -EIO; 180 goto out; 181 } 182 183 if (workspace->strm.total_out >= workspace->strm.total_in) { 184 ret = -E2BIG; 185 goto out; 186 } 187 188 ret = 0; 189 *total_out = workspace->strm.total_out; 190 *total_in = workspace->strm.total_in; 191 out: 192 *out_pages = nr_pages; 193 if (out_page) 194 kunmap(out_page); 195 196 if (in_page) { 197 kunmap(in_page); 198 put_page(in_page); 199 } 200 return ret; 201 } 202 203 static int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 204 { 205 struct workspace *workspace = list_entry(ws, struct workspace, list); 206 int ret = 0, ret2; 207 int wbits = MAX_WBITS; 208 char *data_in; 209 size_t total_out = 0; 210 unsigned long page_in_index = 0; 211 size_t srclen = cb->compressed_len; 212 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); 213 unsigned long buf_start; 214 struct page **pages_in = cb->compressed_pages; 215 u64 disk_start = cb->start; 216 struct bio *orig_bio = cb->orig_bio; 217 218 data_in = kmap(pages_in[page_in_index]); 219 workspace->strm.next_in = data_in; 220 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE); 221 workspace->strm.total_in = 0; 222 223 workspace->strm.total_out = 0; 224 workspace->strm.next_out = workspace->buf; 225 workspace->strm.avail_out = PAGE_SIZE; 226 227 /* If it's deflate, and it's got no preset dictionary, then 228 we can tell zlib to skip the adler32 check. */ 229 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 230 ((data_in[0] & 0x0f) == Z_DEFLATED) && 231 !(((data_in[0]<<8) + data_in[1]) % 31)) { 232 233 wbits = -((data_in[0] >> 4) + 8); 234 workspace->strm.next_in += 2; 235 workspace->strm.avail_in -= 2; 236 } 237 238 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 239 pr_warn("BTRFS: inflateInit failed\n"); 240 kunmap(pages_in[page_in_index]); 241 return -EIO; 242 } 243 while (workspace->strm.total_in < srclen) { 244 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 245 if (ret != Z_OK && ret != Z_STREAM_END) 246 break; 247 248 buf_start = total_out; 249 total_out = workspace->strm.total_out; 250 251 /* we didn't make progress in this inflate call, we're done */ 252 if (buf_start == total_out) 253 break; 254 255 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, 256 total_out, disk_start, 257 orig_bio); 258 if (ret2 == 0) { 259 ret = 0; 260 goto done; 261 } 262 263 workspace->strm.next_out = workspace->buf; 264 workspace->strm.avail_out = PAGE_SIZE; 265 266 if (workspace->strm.avail_in == 0) { 267 unsigned long tmp; 268 kunmap(pages_in[page_in_index]); 269 page_in_index++; 270 if (page_in_index >= total_pages_in) { 271 data_in = NULL; 272 break; 273 } 274 data_in = kmap(pages_in[page_in_index]); 275 workspace->strm.next_in = data_in; 276 tmp = srclen - workspace->strm.total_in; 277 workspace->strm.avail_in = min(tmp, 278 PAGE_SIZE); 279 } 280 } 281 if (ret != Z_STREAM_END) 282 ret = -EIO; 283 else 284 ret = 0; 285 done: 286 zlib_inflateEnd(&workspace->strm); 287 if (data_in) 288 kunmap(pages_in[page_in_index]); 289 if (!ret) 290 zero_fill_bio(orig_bio); 291 return ret; 292 } 293 294 static int zlib_decompress(struct list_head *ws, unsigned char *data_in, 295 struct page *dest_page, 296 unsigned long start_byte, 297 size_t srclen, size_t destlen) 298 { 299 struct workspace *workspace = list_entry(ws, struct workspace, list); 300 int ret = 0; 301 int wbits = MAX_WBITS; 302 unsigned long bytes_left; 303 unsigned long total_out = 0; 304 unsigned long pg_offset = 0; 305 char *kaddr; 306 307 destlen = min_t(unsigned long, destlen, PAGE_SIZE); 308 bytes_left = destlen; 309 310 workspace->strm.next_in = data_in; 311 workspace->strm.avail_in = srclen; 312 workspace->strm.total_in = 0; 313 314 workspace->strm.next_out = workspace->buf; 315 workspace->strm.avail_out = PAGE_SIZE; 316 workspace->strm.total_out = 0; 317 /* If it's deflate, and it's got no preset dictionary, then 318 we can tell zlib to skip the adler32 check. */ 319 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 320 ((data_in[0] & 0x0f) == Z_DEFLATED) && 321 !(((data_in[0]<<8) + data_in[1]) % 31)) { 322 323 wbits = -((data_in[0] >> 4) + 8); 324 workspace->strm.next_in += 2; 325 workspace->strm.avail_in -= 2; 326 } 327 328 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 329 pr_warn("BTRFS: inflateInit failed\n"); 330 return -EIO; 331 } 332 333 while (bytes_left > 0) { 334 unsigned long buf_start; 335 unsigned long buf_offset; 336 unsigned long bytes; 337 338 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 339 if (ret != Z_OK && ret != Z_STREAM_END) 340 break; 341 342 buf_start = total_out; 343 total_out = workspace->strm.total_out; 344 345 if (total_out == buf_start) { 346 ret = -EIO; 347 break; 348 } 349 350 if (total_out <= start_byte) 351 goto next; 352 353 if (total_out > start_byte && buf_start < start_byte) 354 buf_offset = start_byte - buf_start; 355 else 356 buf_offset = 0; 357 358 bytes = min(PAGE_SIZE - pg_offset, 359 PAGE_SIZE - buf_offset); 360 bytes = min(bytes, bytes_left); 361 362 kaddr = kmap_atomic(dest_page); 363 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes); 364 kunmap_atomic(kaddr); 365 366 pg_offset += bytes; 367 bytes_left -= bytes; 368 next: 369 workspace->strm.next_out = workspace->buf; 370 workspace->strm.avail_out = PAGE_SIZE; 371 } 372 373 if (ret != Z_STREAM_END && bytes_left != 0) 374 ret = -EIO; 375 else 376 ret = 0; 377 378 zlib_inflateEnd(&workspace->strm); 379 380 /* 381 * this should only happen if zlib returned fewer bytes than we 382 * expected. btrfs_get_block is responsible for zeroing from the 383 * end of the inline extent (destlen) to the end of the page 384 */ 385 if (pg_offset < destlen) { 386 kaddr = kmap_atomic(dest_page); 387 memset(kaddr + pg_offset, 0, destlen - pg_offset); 388 kunmap_atomic(kaddr); 389 } 390 return ret; 391 } 392 393 static void zlib_set_level(struct list_head *ws, unsigned int type) 394 { 395 struct workspace *workspace = list_entry(ws, struct workspace, list); 396 unsigned level = (type & 0xF0) >> 4; 397 398 if (level > 9) 399 level = 9; 400 401 workspace->level = level > 0 ? level : 3; 402 } 403 404 const struct btrfs_compress_op btrfs_zlib_compress = { 405 .alloc_workspace = zlib_alloc_workspace, 406 .free_workspace = zlib_free_workspace, 407 .compress_pages = zlib_compress_pages, 408 .decompress_bio = zlib_decompress_bio, 409 .decompress = zlib_decompress, 410 .set_level = zlib_set_level, 411 }; 412