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 strm; 37 char *buf; 38 struct list_head list; 39 }; 40 41 static void zlib_free_workspace(struct list_head *ws) 42 { 43 struct workspace *workspace = list_entry(ws, struct workspace, list); 44 45 vfree(workspace->strm.workspace); 46 kfree(workspace->buf); 47 kfree(workspace); 48 } 49 50 static struct list_head *zlib_alloc_workspace(void) 51 { 52 struct workspace *workspace; 53 int workspacesize; 54 55 workspace = kzalloc(sizeof(*workspace), GFP_NOFS); 56 if (!workspace) 57 return ERR_PTR(-ENOMEM); 58 59 workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL), 60 zlib_inflate_workspacesize()); 61 workspace->strm.workspace = vmalloc(workspacesize); 62 workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS); 63 if (!workspace->strm.workspace || !workspace->buf) 64 goto fail; 65 66 INIT_LIST_HEAD(&workspace->list); 67 68 return &workspace->list; 69 fail: 70 zlib_free_workspace(&workspace->list); 71 return ERR_PTR(-ENOMEM); 72 } 73 74 static int zlib_compress_pages(struct list_head *ws, 75 struct address_space *mapping, 76 u64 start, unsigned long len, 77 struct page **pages, 78 unsigned long nr_dest_pages, 79 unsigned long *out_pages, 80 unsigned long *total_in, 81 unsigned long *total_out, 82 unsigned long max_out) 83 { 84 struct workspace *workspace = list_entry(ws, struct workspace, list); 85 int ret; 86 char *data_in; 87 char *cpage_out; 88 int nr_pages = 0; 89 struct page *in_page = NULL; 90 struct page *out_page = NULL; 91 unsigned long bytes_left; 92 93 *out_pages = 0; 94 *total_out = 0; 95 *total_in = 0; 96 97 if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) { 98 printk(KERN_WARNING "BTRFS: deflateInit failed\n"); 99 ret = -EIO; 100 goto out; 101 } 102 103 workspace->strm.total_in = 0; 104 workspace->strm.total_out = 0; 105 106 in_page = find_get_page(mapping, start >> PAGE_SHIFT); 107 data_in = kmap(in_page); 108 109 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 110 if (out_page == NULL) { 111 ret = -ENOMEM; 112 goto out; 113 } 114 cpage_out = kmap(out_page); 115 pages[0] = out_page; 116 nr_pages = 1; 117 118 workspace->strm.next_in = data_in; 119 workspace->strm.next_out = cpage_out; 120 workspace->strm.avail_out = PAGE_SIZE; 121 workspace->strm.avail_in = min(len, PAGE_SIZE); 122 123 while (workspace->strm.total_in < len) { 124 ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH); 125 if (ret != Z_OK) { 126 printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n", 127 ret); 128 zlib_deflateEnd(&workspace->strm); 129 ret = -EIO; 130 goto out; 131 } 132 133 /* we're making it bigger, give up */ 134 if (workspace->strm.total_in > 8192 && 135 workspace->strm.total_in < 136 workspace->strm.total_out) { 137 ret = -E2BIG; 138 goto out; 139 } 140 /* we need another page for writing out. Test this 141 * before the total_in so we will pull in a new page for 142 * the stream end if required 143 */ 144 if (workspace->strm.avail_out == 0) { 145 kunmap(out_page); 146 if (nr_pages == nr_dest_pages) { 147 out_page = NULL; 148 ret = -E2BIG; 149 goto out; 150 } 151 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); 152 if (out_page == NULL) { 153 ret = -ENOMEM; 154 goto out; 155 } 156 cpage_out = kmap(out_page); 157 pages[nr_pages] = out_page; 158 nr_pages++; 159 workspace->strm.avail_out = PAGE_SIZE; 160 workspace->strm.next_out = cpage_out; 161 } 162 /* we're all done */ 163 if (workspace->strm.total_in >= len) 164 break; 165 166 /* we've read in a full page, get a new one */ 167 if (workspace->strm.avail_in == 0) { 168 if (workspace->strm.total_out > max_out) 169 break; 170 171 bytes_left = len - workspace->strm.total_in; 172 kunmap(in_page); 173 put_page(in_page); 174 175 start += PAGE_SIZE; 176 in_page = find_get_page(mapping, 177 start >> PAGE_SHIFT); 178 data_in = kmap(in_page); 179 workspace->strm.avail_in = min(bytes_left, 180 PAGE_SIZE); 181 workspace->strm.next_in = data_in; 182 } 183 } 184 workspace->strm.avail_in = 0; 185 ret = zlib_deflate(&workspace->strm, Z_FINISH); 186 zlib_deflateEnd(&workspace->strm); 187 188 if (ret != Z_STREAM_END) { 189 ret = -EIO; 190 goto out; 191 } 192 193 if (workspace->strm.total_out >= workspace->strm.total_in) { 194 ret = -E2BIG; 195 goto out; 196 } 197 198 ret = 0; 199 *total_out = workspace->strm.total_out; 200 *total_in = workspace->strm.total_in; 201 out: 202 *out_pages = nr_pages; 203 if (out_page) 204 kunmap(out_page); 205 206 if (in_page) { 207 kunmap(in_page); 208 put_page(in_page); 209 } 210 return ret; 211 } 212 213 static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in, 214 u64 disk_start, 215 struct bio_vec *bvec, 216 int vcnt, 217 size_t srclen) 218 { 219 struct workspace *workspace = list_entry(ws, struct workspace, list); 220 int ret = 0, ret2; 221 int wbits = MAX_WBITS; 222 char *data_in; 223 size_t total_out = 0; 224 unsigned long page_in_index = 0; 225 unsigned long page_out_index = 0; 226 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE); 227 unsigned long buf_start; 228 unsigned long pg_offset; 229 230 data_in = kmap(pages_in[page_in_index]); 231 workspace->strm.next_in = data_in; 232 workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE); 233 workspace->strm.total_in = 0; 234 235 workspace->strm.total_out = 0; 236 workspace->strm.next_out = workspace->buf; 237 workspace->strm.avail_out = PAGE_SIZE; 238 pg_offset = 0; 239 240 /* If it's deflate, and it's got no preset dictionary, then 241 we can tell zlib to skip the adler32 check. */ 242 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 243 ((data_in[0] & 0x0f) == Z_DEFLATED) && 244 !(((data_in[0]<<8) + data_in[1]) % 31)) { 245 246 wbits = -((data_in[0] >> 4) + 8); 247 workspace->strm.next_in += 2; 248 workspace->strm.avail_in -= 2; 249 } 250 251 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 252 printk(KERN_WARNING "BTRFS: inflateInit failed\n"); 253 return -EIO; 254 } 255 while (workspace->strm.total_in < srclen) { 256 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 257 if (ret != Z_OK && ret != Z_STREAM_END) 258 break; 259 260 buf_start = total_out; 261 total_out = workspace->strm.total_out; 262 263 /* we didn't make progress in this inflate call, we're done */ 264 if (buf_start == total_out) 265 break; 266 267 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start, 268 total_out, disk_start, 269 bvec, vcnt, 270 &page_out_index, &pg_offset); 271 if (ret2 == 0) { 272 ret = 0; 273 goto done; 274 } 275 276 workspace->strm.next_out = workspace->buf; 277 workspace->strm.avail_out = PAGE_SIZE; 278 279 if (workspace->strm.avail_in == 0) { 280 unsigned long tmp; 281 kunmap(pages_in[page_in_index]); 282 page_in_index++; 283 if (page_in_index >= total_pages_in) { 284 data_in = NULL; 285 break; 286 } 287 data_in = kmap(pages_in[page_in_index]); 288 workspace->strm.next_in = data_in; 289 tmp = srclen - workspace->strm.total_in; 290 workspace->strm.avail_in = min(tmp, 291 PAGE_SIZE); 292 } 293 } 294 if (ret != Z_STREAM_END) 295 ret = -EIO; 296 else 297 ret = 0; 298 done: 299 zlib_inflateEnd(&workspace->strm); 300 if (data_in) 301 kunmap(pages_in[page_in_index]); 302 if (!ret) 303 btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset); 304 return ret; 305 } 306 307 static int zlib_decompress(struct list_head *ws, unsigned char *data_in, 308 struct page *dest_page, 309 unsigned long start_byte, 310 size_t srclen, size_t destlen) 311 { 312 struct workspace *workspace = list_entry(ws, struct workspace, list); 313 int ret = 0; 314 int wbits = MAX_WBITS; 315 unsigned long bytes_left; 316 unsigned long total_out = 0; 317 unsigned long pg_offset = 0; 318 char *kaddr; 319 320 destlen = min_t(unsigned long, destlen, PAGE_SIZE); 321 bytes_left = destlen; 322 323 workspace->strm.next_in = data_in; 324 workspace->strm.avail_in = srclen; 325 workspace->strm.total_in = 0; 326 327 workspace->strm.next_out = workspace->buf; 328 workspace->strm.avail_out = PAGE_SIZE; 329 workspace->strm.total_out = 0; 330 /* If it's deflate, and it's got no preset dictionary, then 331 we can tell zlib to skip the adler32 check. */ 332 if (srclen > 2 && !(data_in[1] & PRESET_DICT) && 333 ((data_in[0] & 0x0f) == Z_DEFLATED) && 334 !(((data_in[0]<<8) + data_in[1]) % 31)) { 335 336 wbits = -((data_in[0] >> 4) + 8); 337 workspace->strm.next_in += 2; 338 workspace->strm.avail_in -= 2; 339 } 340 341 if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) { 342 printk(KERN_WARNING "BTRFS: inflateInit failed\n"); 343 return -EIO; 344 } 345 346 while (bytes_left > 0) { 347 unsigned long buf_start; 348 unsigned long buf_offset; 349 unsigned long bytes; 350 351 ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH); 352 if (ret != Z_OK && ret != Z_STREAM_END) 353 break; 354 355 buf_start = total_out; 356 total_out = workspace->strm.total_out; 357 358 if (total_out == buf_start) { 359 ret = -EIO; 360 break; 361 } 362 363 if (total_out <= start_byte) 364 goto next; 365 366 if (total_out > start_byte && buf_start < start_byte) 367 buf_offset = start_byte - buf_start; 368 else 369 buf_offset = 0; 370 371 bytes = min(PAGE_SIZE - pg_offset, 372 PAGE_SIZE - buf_offset); 373 bytes = min(bytes, bytes_left); 374 375 kaddr = kmap_atomic(dest_page); 376 memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes); 377 kunmap_atomic(kaddr); 378 379 pg_offset += bytes; 380 bytes_left -= bytes; 381 next: 382 workspace->strm.next_out = workspace->buf; 383 workspace->strm.avail_out = PAGE_SIZE; 384 } 385 386 if (ret != Z_STREAM_END && bytes_left != 0) 387 ret = -EIO; 388 else 389 ret = 0; 390 391 zlib_inflateEnd(&workspace->strm); 392 393 /* 394 * this should only happen if zlib returned fewer bytes than we 395 * expected. btrfs_get_block is responsible for zeroing from the 396 * end of the inline extent (destlen) to the end of the page 397 */ 398 if (pg_offset < destlen) { 399 kaddr = kmap_atomic(dest_page); 400 memset(kaddr + pg_offset, 0, destlen - pg_offset); 401 kunmap_atomic(kaddr); 402 } 403 return ret; 404 } 405 406 const struct btrfs_compress_op btrfs_zlib_compress = { 407 .alloc_workspace = zlib_alloc_workspace, 408 .free_workspace = zlib_free_workspace, 409 .compress_pages = zlib_compress_pages, 410 .decompress_biovec = zlib_decompress_biovec, 411 .decompress = zlib_decompress, 412 }; 413