1 /* 2 * Copyright (C) 2008 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 * 18 * Based on jffs2 zlib code: 19 * Copyright © 2001-2007 Red Hat, Inc. 20 * Created by David Woodhouse <dwmw2@infradead.org> 21 */ 22 23 #include <linux/kernel.h> 24 #include <linux/slab.h> 25 #include <linux/zlib.h> 26 #include <linux/zutil.h> 27 #include <linux/vmalloc.h> 28 #include <linux/init.h> 29 #include <linux/err.h> 30 #include <linux/sched.h> 31 #include <linux/pagemap.h> 32 #include <linux/bio.h> 33 #include "compression.h" 34 35 struct workspace { 36 z_stream inf_strm; 37 z_stream def_strm; 38 char *buf; 39 struct list_head list; 40 }; 41 42 static void zlib_free_workspace(struct list_head *ws) 43 { 44 struct workspace *workspace = list_entry(ws, struct workspace, list); 45 46 vfree(workspace->def_strm.workspace); 47 vfree(workspace->inf_strm.workspace); 48 kfree(workspace->buf); 49 kfree(workspace); 50 } 51 52 static struct list_head *zlib_alloc_workspace(void) 53 { 54 struct workspace *workspace; 55 56 workspace = kzalloc(sizeof(*workspace), GFP_NOFS); 57 if (!workspace) 58 return ERR_PTR(-ENOMEM); 59 60 workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize( 61 MAX_WBITS, MAX_MEM_LEVEL)); 62 workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize()); 63 workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS); 64 if (!workspace->def_strm.workspace || 65 !workspace->inf_strm.workspace || !workspace->buf) 66 goto fail; 67 68 INIT_LIST_HEAD(&workspace->list); 69 70 return &workspace->list; 71 fail: 72 zlib_free_workspace(&workspace->list); 73 return ERR_PTR(-ENOMEM); 74 } 75 76 static int zlib_compress_pages(struct list_head *ws, 77 struct address_space *mapping, 78 u64 start, unsigned long len, 79 struct page **pages, 80 unsigned long nr_dest_pages, 81 unsigned long *out_pages, 82 unsigned long *total_in, 83 unsigned long *total_out, 84 unsigned long max_out) 85 { 86 struct workspace *workspace = list_entry(ws, struct workspace, list); 87 int ret; 88 char *data_in; 89 char *cpage_out; 90 int nr_pages = 0; 91 struct page *in_page = NULL; 92 struct page *out_page = NULL; 93 unsigned long bytes_left; 94 95 *out_pages = 0; 96 *total_out = 0; 97 *total_in = 0; 98 99 if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) { 100 printk(KERN_WARNING "deflateInit failed\n"); 101 ret = -1; 102 goto out; 103 } 104 105 workspace->def_strm.total_in = 0; 106 workspace->def_strm.total_out = 0; 107 108 in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT); 109 data_in = kmap(in_page); 110 111 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 112 if (out_page == NULL) { 113 ret = -1; 114 goto out; 115 } 116 cpage_out = kmap(out_page); 117 pages[0] = out_page; 118 nr_pages = 1; 119 120 workspace->def_strm.next_in = data_in; 121 workspace->def_strm.next_out = cpage_out; 122 workspace->def_strm.avail_out = PAGE_CACHE_SIZE; 123 workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE); 124 125 while (workspace->def_strm.total_in < len) { 126 ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH); 127 if (ret != Z_OK) { 128 printk(KERN_DEBUG "btrfs deflate in loop returned %d\n", 129 ret); 130 zlib_deflateEnd(&workspace->def_strm); 131 ret = -1; 132 goto out; 133 } 134 135 /* we're making it bigger, give up */ 136 if (workspace->def_strm.total_in > 8192 && 137 workspace->def_strm.total_in < 138 workspace->def_strm.total_out) { 139 ret = -1; 140 goto out; 141 } 142 /* we need another page for writing out. Test this 143 * before the total_in so we will pull in a new page for 144 * the stream end if required 145 */ 146 if (workspace->def_strm.avail_out == 0) { 147 kunmap(out_page); 148 if (nr_pages == nr_dest_pages) { 149 out_page = NULL; 150 ret = -1; 151 goto out; 152 } 153 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 154 if (out_page == NULL) { 155 ret = -1; 156 goto out; 157 } 158 cpage_out = kmap(out_page); 159 pages[nr_pages] = out_page; 160 nr_pages++; 161 workspace->def_strm.avail_out = PAGE_CACHE_SIZE; 162 workspace->def_strm.next_out = cpage_out; 163 } 164 /* we're all done */ 165 if (workspace->def_strm.total_in >= len) 166 break; 167 168 /* we've read in a full page, get a new one */ 169 if (workspace->def_strm.avail_in == 0) { 170 if (workspace->def_strm.total_out > max_out) 171 break; 172 173 bytes_left = len - workspace->def_strm.total_in; 174 kunmap(in_page); 175 page_cache_release(in_page); 176 177 start += PAGE_CACHE_SIZE; 178 in_page = find_get_page(mapping, 179 start >> PAGE_CACHE_SHIFT); 180 data_in = kmap(in_page); 181 workspace->def_strm.avail_in = min(bytes_left, 182 PAGE_CACHE_SIZE); 183 workspace->def_strm.next_in = data_in; 184 } 185 } 186 workspace->def_strm.avail_in = 0; 187 ret = zlib_deflate(&workspace->def_strm, Z_FINISH); 188 zlib_deflateEnd(&workspace->def_strm); 189 190 if (ret != Z_STREAM_END) { 191 ret = -1; 192 goto out; 193 } 194 195 if (workspace->def_strm.total_out >= workspace->def_strm.total_in) { 196 ret = -1; 197 goto out; 198 } 199 200 ret = 0; 201 *total_out = workspace->def_strm.total_out; 202 *total_in = workspace->def_strm.total_in; 203 out: 204 *out_pages = nr_pages; 205 if (out_page) 206 kunmap(out_page); 207 208 if (in_page) { 209 kunmap(in_page); 210 page_cache_release(in_page); 211 } 212 return ret; 213 } 214 215 static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 216 u64 disk_start, 217 struct bio_vec *bvec, 218 int vcnt, 219 size_t srclen) 220 { 221 struct workspace *workspace = list_entry(ws, struct workspace, list); 222 int ret = 0, ret2; 223 int wbits = MAX_WBITS; 224 char *data_in; 225 size_t total_out = 0; 226 unsigned long page_in_index = 0; 227 unsigned long page_out_index = 0; 228 unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) / 229 PAGE_CACHE_SIZE; 230 unsigned long buf_start; 231 unsigned long pg_offset; 232 233 data_in = kmap(pages_in[page_in_index]); 234 workspace->inf_strm.next_in = data_in; 235 workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE); 236 workspace->inf_strm.total_in = 0; 237 238 workspace->inf_strm.total_out = 0; 239 workspace->inf_strm.next_out = workspace->buf; 240 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; 241 pg_offset = 0; 242 243 /* If it's deflate, and it's got no preset dictionary, then 244 we can tell zlib to skip the adler32 check. */ 245 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 246 ((data_in[0] & 0x0f) == Z_DEFLATED) && 247 !(((data_in[0]<<8) + data_in[1]) % 31)) { 248 249 wbits = -((data_in[0] >> 4) + 8); 250 workspace->inf_strm.next_in += 2; 251 workspace->inf_strm.avail_in -= 2; 252 } 253 254 if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) { 255 printk(KERN_WARNING "inflateInit failed\n"); 256 return -1; 257 } 258 while (workspace->inf_strm.total_in < srclen) { 259 ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH); 260 if (ret != Z_OK && ret != Z_STREAM_END) 261 break; 262 263 buf_start = total_out; 264 total_out = workspace->inf_strm.total_out; 265 266 /* we didn't make progress in this inflate call, we're done */ 267 if (buf_start == total_out) 268 break; 269 270 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, 271 total_out, disk_start, 272 bvec, vcnt, 273 &page_out_index, &pg_offset); 274 if (ret2 == 0) { 275 ret = 0; 276 goto done; 277 } 278 279 workspace->inf_strm.next_out = workspace->buf; 280 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; 281 282 if (workspace->inf_strm.avail_in == 0) { 283 unsigned long tmp; 284 kunmap(pages_in[page_in_index]); 285 page_in_index++; 286 if (page_in_index >= total_pages_in) { 287 data_in = NULL; 288 break; 289 } 290 data_in = kmap(pages_in[page_in_index]); 291 workspace->inf_strm.next_in = data_in; 292 tmp = srclen - workspace->inf_strm.total_in; 293 workspace->inf_strm.avail_in = min(tmp, 294 PAGE_CACHE_SIZE); 295 } 296 } 297 if (ret != Z_STREAM_END) 298 ret = -1; 299 else 300 ret = 0; 301 done: 302 zlib_inflateEnd(&workspace->inf_strm); 303 if (data_in) 304 kunmap(pages_in[page_in_index]); 305 return ret; 306 } 307 308 static int zlib_decompress(struct list_head *ws, unsigned char *data_in, 309 struct page *dest_page, 310 unsigned long start_byte, 311 size_t srclen, size_t destlen) 312 { 313 struct workspace *workspace = list_entry(ws, struct workspace, list); 314 int ret = 0; 315 int wbits = MAX_WBITS; 316 unsigned long bytes_left = destlen; 317 unsigned long total_out = 0; 318 char *kaddr; 319 320 workspace->inf_strm.next_in = data_in; 321 workspace->inf_strm.avail_in = srclen; 322 workspace->inf_strm.total_in = 0; 323 324 workspace->inf_strm.next_out = workspace->buf; 325 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; 326 workspace->inf_strm.total_out = 0; 327 /* If it's deflate, and it's got no preset dictionary, then 328 we can tell zlib to skip the adler32 check. */ 329 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 330 ((data_in[0] & 0x0f) == Z_DEFLATED) && 331 !(((data_in[0]<<8) + data_in[1]) % 31)) { 332 333 wbits = -((data_in[0] >> 4) + 8); 334 workspace->inf_strm.next_in += 2; 335 workspace->inf_strm.avail_in -= 2; 336 } 337 338 if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) { 339 printk(KERN_WARNING "inflateInit failed\n"); 340 return -1; 341 } 342 343 while (bytes_left > 0) { 344 unsigned long buf_start; 345 unsigned long buf_offset; 346 unsigned long bytes; 347 unsigned long pg_offset = 0; 348 349 ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH); 350 if (ret != Z_OK && ret != Z_STREAM_END) 351 break; 352 353 buf_start = total_out; 354 total_out = workspace->inf_strm.total_out; 355 356 if (total_out == buf_start) { 357 ret = -1; 358 break; 359 } 360 361 if (total_out <= start_byte) 362 goto next; 363 364 if (total_out > start_byte && buf_start < start_byte) 365 buf_offset = start_byte - buf_start; 366 else 367 buf_offset = 0; 368 369 bytes = min(PAGE_CACHE_SIZE - pg_offset, 370 PAGE_CACHE_SIZE - buf_offset); 371 bytes = min(bytes, bytes_left); 372 373 kaddr = kmap_atomic(dest_page, KM_USER0); 374 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes); 375 kunmap_atomic(kaddr, KM_USER0); 376 377 pg_offset += bytes; 378 bytes_left -= bytes; 379 next: 380 workspace->inf_strm.next_out = workspace->buf; 381 workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; 382 } 383 384 if (ret != Z_STREAM_END && bytes_left != 0) 385 ret = -1; 386 else 387 ret = 0; 388 389 zlib_inflateEnd(&workspace->inf_strm); 390 return ret; 391 } 392 393 struct btrfs_compress_op btrfs_zlib_compress = { 394 .alloc_workspace = zlib_alloc_workspace, 395 .free_workspace = zlib_free_workspace, 396 .compress_pages = zlib_compress_pages, 397 .decompress_biovec = zlib_decompress_biovec, 398 .decompress = zlib_decompress, 399 }; 400