1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2008 Oracle. All rights reserved. 4 */ 5 6#include <linux/kernel.h> 7#include <linux/slab.h> 8#include <linux/mm.h> 9#include <linux/init.h> 10#include <linux/err.h> 11#include <linux/sched.h> 12#include <linux/pagemap.h> 13#include <linux/bio.h> 14#include <linux/lzo.h> 15#include <linux/refcount.h> 16#include "messages.h" 17#include "compression.h" 18#include "ctree.h" 19#include "super.h" 20#include "btrfs_inode.h" 21 22#define LZO_LEN 4 23 24/* 25 * Btrfs LZO compression format 26 * 27 * Regular and inlined LZO compressed data extents consist of: 28 * 29 * 1. Header 30 * Fixed size. LZO_LEN (4) bytes long, LE32. 31 * Records the total size (including the header) of compressed data. 32 * 33 * 2. Segment(s) 34 * Variable size. Each segment includes one segment header, followed by data 35 * payload. 36 * One regular LZO compressed extent can have one or more segments. 37 * For inlined LZO compressed extent, only one segment is allowed. 38 * One segment represents at most one sector of uncompressed data. 39 * 40 * 2.1 Segment header 41 * Fixed size. LZO_LEN (4) bytes long, LE32. 42 * Records the total size of the segment (not including the header). 43 * Segment header never crosses sector boundary, thus it's possible to 44 * have at most 3 padding zeros at the end of the sector. 45 * 46 * 2.2 Data Payload 47 * Variable size. Size up limit should be lzo1x_worst_compress(sectorsize) 48 * which is 4419 for a 4KiB sectorsize. 49 * 50 * Example with 4K sectorsize: 51 * Page 1: 52 * 0 0x2 0x4 0x6 0x8 0xa 0xc 0xe 0x10 53 * 0x0000 | Header | SegHdr 01 | Data payload 01 ... | 54 * ... 55 * 0x0ff0 | SegHdr N | Data payload N ... |00| 56 * ^^ padding zeros 57 * Page 2: 58 * 0x1000 | SegHdr N+1| Data payload N+1 ... | 59 */ 60 61#define WORKSPACE_BUF_LENGTH (lzo1x_worst_compress(PAGE_SIZE)) 62#define WORKSPACE_CBUF_LENGTH (lzo1x_worst_compress(PAGE_SIZE)) 63 64struct workspace { 65 void *mem; 66 void *buf; /* where decompressed data goes */ 67 void *cbuf; /* where compressed data goes */ 68 struct list_head list; 69}; 70 71static struct workspace_manager wsm; 72 73void lzo_free_workspace(struct list_head *ws) 74{ 75 struct workspace *workspace = list_entry(ws, struct workspace, list); 76 77 kvfree(workspace->buf); 78 kvfree(workspace->cbuf); 79 kvfree(workspace->mem); 80 kfree(workspace); 81} 82 83struct list_head *lzo_alloc_workspace(unsigned int level) 84{ 85 struct workspace *workspace; 86 87 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL); 88 if (!workspace) 89 return ERR_PTR(-ENOMEM); 90 91 workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL | __GFP_NOWARN); 92 workspace->buf = kvmalloc(WORKSPACE_BUF_LENGTH, GFP_KERNEL | __GFP_NOWARN); 93 workspace->cbuf = kvmalloc(WORKSPACE_CBUF_LENGTH, GFP_KERNEL | __GFP_NOWARN); 94 if (!workspace->mem || !workspace->buf || !workspace->cbuf) 95 goto fail; 96 97 INIT_LIST_HEAD(&workspace->list); 98 99 return &workspace->list; 100fail: 101 lzo_free_workspace(&workspace->list); 102 return ERR_PTR(-ENOMEM); 103} 104 105static inline void write_compress_length(char *buf, size_t len) 106{ 107 __le32 dlen; 108 109 dlen = cpu_to_le32(len); 110 memcpy(buf, &dlen, LZO_LEN); 111} 112 113static inline size_t read_compress_length(const char *buf) 114{ 115 __le32 dlen; 116 117 memcpy(&dlen, buf, LZO_LEN); 118 return le32_to_cpu(dlen); 119} 120 121/* 122 * Will do: 123 * 124 * - Write a segment header into the destination 125 * - Copy the compressed buffer into the destination 126 * - Make sure we have enough space in the last sector to fit a segment header 127 * If not, we will pad at most (LZO_LEN (4)) - 1 bytes of zeros. 128 * 129 * Will allocate new pages when needed. 130 */ 131static int copy_compressed_data_to_page(char *compressed_data, 132 size_t compressed_size, 133 struct page **out_pages, 134 unsigned long max_nr_page, 135 u32 *cur_out, 136 const u32 sectorsize) 137{ 138 u32 sector_bytes_left; 139 u32 orig_out; 140 struct page *cur_page; 141 char *kaddr; 142 143 if ((*cur_out / PAGE_SIZE) >= max_nr_page) 144 return -E2BIG; 145 146 /* 147 * We never allow a segment header crossing sector boundary, previous 148 * run should ensure we have enough space left inside the sector. 149 */ 150 ASSERT((*cur_out / sectorsize) == (*cur_out + LZO_LEN - 1) / sectorsize); 151 152 cur_page = out_pages[*cur_out / PAGE_SIZE]; 153 /* Allocate a new page */ 154 if (!cur_page) { 155 cur_page = btrfs_alloc_compr_page(); 156 if (!cur_page) 157 return -ENOMEM; 158 out_pages[*cur_out / PAGE_SIZE] = cur_page; 159 } 160 161 kaddr = kmap_local_page(cur_page); 162 write_compress_length(kaddr + offset_in_page(*cur_out), 163 compressed_size); 164 *cur_out += LZO_LEN; 165 166 orig_out = *cur_out; 167 168 /* Copy compressed data */ 169 while (*cur_out - orig_out < compressed_size) { 170 u32 copy_len = min_t(u32, sectorsize - *cur_out % sectorsize, 171 orig_out + compressed_size - *cur_out); 172 173 kunmap_local(kaddr); 174 175 if ((*cur_out / PAGE_SIZE) >= max_nr_page) 176 return -E2BIG; 177 178 cur_page = out_pages[*cur_out / PAGE_SIZE]; 179 /* Allocate a new page */ 180 if (!cur_page) { 181 cur_page = btrfs_alloc_compr_page(); 182 if (!cur_page) 183 return -ENOMEM; 184 out_pages[*cur_out / PAGE_SIZE] = cur_page; 185 } 186 kaddr = kmap_local_page(cur_page); 187 188 memcpy(kaddr + offset_in_page(*cur_out), 189 compressed_data + *cur_out - orig_out, copy_len); 190 191 *cur_out += copy_len; 192 } 193 194 /* 195 * Check if we can fit the next segment header into the remaining space 196 * of the sector. 197 */ 198 sector_bytes_left = round_up(*cur_out, sectorsize) - *cur_out; 199 if (sector_bytes_left >= LZO_LEN || sector_bytes_left == 0) 200 goto out; 201 202 /* The remaining size is not enough, pad it with zeros */ 203 memset(kaddr + offset_in_page(*cur_out), 0, 204 sector_bytes_left); 205 *cur_out += sector_bytes_left; 206 207out: 208 kunmap_local(kaddr); 209 return 0; 210} 211 212int lzo_compress_pages(struct list_head *ws, struct address_space *mapping, 213 u64 start, struct page **pages, unsigned long *out_pages, 214 unsigned long *total_in, unsigned long *total_out) 215{ 216 struct workspace *workspace = list_entry(ws, struct workspace, list); 217 const u32 sectorsize = inode_to_fs_info(mapping->host)->sectorsize; 218 struct page *page_in = NULL; 219 char *sizes_ptr; 220 const unsigned long max_nr_page = *out_pages; 221 int ret = 0; 222 /* Points to the file offset of input data */ 223 u64 cur_in = start; 224 /* Points to the current output byte */ 225 u32 cur_out = 0; 226 u32 len = *total_out; 227 228 ASSERT(max_nr_page > 0); 229 *out_pages = 0; 230 *total_out = 0; 231 *total_in = 0; 232 233 /* 234 * Skip the header for now, we will later come back and write the total 235 * compressed size 236 */ 237 cur_out += LZO_LEN; 238 while (cur_in < start + len) { 239 char *data_in; 240 const u32 sectorsize_mask = sectorsize - 1; 241 u32 sector_off = (cur_in - start) & sectorsize_mask; 242 u32 in_len; 243 size_t out_len; 244 245 /* Get the input page first */ 246 if (!page_in) { 247 page_in = find_get_page(mapping, cur_in >> PAGE_SHIFT); 248 ASSERT(page_in); 249 } 250 251 /* Compress at most one sector of data each time */ 252 in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off); 253 ASSERT(in_len); 254 data_in = kmap_local_page(page_in); 255 ret = lzo1x_1_compress(data_in + 256 offset_in_page(cur_in), in_len, 257 workspace->cbuf, &out_len, 258 workspace->mem); 259 kunmap_local(data_in); 260 if (ret < 0) { 261 pr_debug("BTRFS: lzo in loop returned %d\n", ret); 262 ret = -EIO; 263 goto out; 264 } 265 266 ret = copy_compressed_data_to_page(workspace->cbuf, out_len, 267 pages, max_nr_page, 268 &cur_out, sectorsize); 269 if (ret < 0) 270 goto out; 271 272 cur_in += in_len; 273 274 /* 275 * Check if we're making it bigger after two sectors. And if 276 * it is so, give up. 277 */ 278 if (cur_in - start > sectorsize * 2 && cur_in - start < cur_out) { 279 ret = -E2BIG; 280 goto out; 281 } 282 283 /* Check if we have reached page boundary */ 284 if (PAGE_ALIGNED(cur_in)) { 285 put_page(page_in); 286 page_in = NULL; 287 } 288 } 289 290 /* Store the size of all chunks of compressed data */ 291 sizes_ptr = kmap_local_page(pages[0]); 292 write_compress_length(sizes_ptr, cur_out); 293 kunmap_local(sizes_ptr); 294 295 ret = 0; 296 *total_out = cur_out; 297 *total_in = cur_in - start; 298out: 299 if (page_in) 300 put_page(page_in); 301 *out_pages = DIV_ROUND_UP(cur_out, PAGE_SIZE); 302 return ret; 303} 304 305/* 306 * Copy the compressed segment payload into @dest. 307 * 308 * For the payload there will be no padding, just need to do page switching. 309 */ 310static void copy_compressed_segment(struct compressed_bio *cb, 311 char *dest, u32 len, u32 *cur_in) 312{ 313 u32 orig_in = *cur_in; 314 315 while (*cur_in < orig_in + len) { 316 struct page *cur_page; 317 u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in), 318 orig_in + len - *cur_in); 319 320 ASSERT(copy_len); 321 cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE]; 322 323 memcpy_from_page(dest + *cur_in - orig_in, cur_page, 324 offset_in_page(*cur_in), copy_len); 325 326 *cur_in += copy_len; 327 } 328} 329 330int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) 331{ 332 struct workspace *workspace = list_entry(ws, struct workspace, list); 333 const struct btrfs_fs_info *fs_info = cb->bbio.inode->root->fs_info; 334 const u32 sectorsize = fs_info->sectorsize; 335 char *kaddr; 336 int ret; 337 /* Compressed data length, can be unaligned */ 338 u32 len_in; 339 /* Offset inside the compressed data */ 340 u32 cur_in = 0; 341 /* Bytes decompressed so far */ 342 u32 cur_out = 0; 343 344 kaddr = kmap_local_page(cb->compressed_pages[0]); 345 len_in = read_compress_length(kaddr); 346 kunmap_local(kaddr); 347 cur_in += LZO_LEN; 348 349 /* 350 * LZO header length check 351 * 352 * The total length should not exceed the maximum extent length, 353 * and all sectors should be used. 354 * If this happens, it means the compressed extent is corrupted. 355 */ 356 if (len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) || 357 round_up(len_in, sectorsize) < cb->compressed_len) { 358 btrfs_err(fs_info, 359 "invalid lzo header, lzo len %u compressed len %u", 360 len_in, cb->compressed_len); 361 return -EUCLEAN; 362 } 363 364 /* Go through each lzo segment */ 365 while (cur_in < len_in) { 366 struct page *cur_page; 367 /* Length of the compressed segment */ 368 u32 seg_len; 369 u32 sector_bytes_left; 370 size_t out_len = lzo1x_worst_compress(sectorsize); 371 372 /* 373 * We should always have enough space for one segment header 374 * inside current sector. 375 */ 376 ASSERT(cur_in / sectorsize == 377 (cur_in + LZO_LEN - 1) / sectorsize); 378 cur_page = cb->compressed_pages[cur_in / PAGE_SIZE]; 379 ASSERT(cur_page); 380 kaddr = kmap_local_page(cur_page); 381 seg_len = read_compress_length(kaddr + offset_in_page(cur_in)); 382 kunmap_local(kaddr); 383 cur_in += LZO_LEN; 384 385 if (seg_len > WORKSPACE_CBUF_LENGTH) { 386 /* 387 * seg_len shouldn't be larger than we have allocated 388 * for workspace->cbuf 389 */ 390 btrfs_err(fs_info, "unexpectedly large lzo segment len %u", 391 seg_len); 392 return -EIO; 393 } 394 395 /* Copy the compressed segment payload into workspace */ 396 copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in); 397 398 /* Decompress the data */ 399 ret = lzo1x_decompress_safe(workspace->cbuf, seg_len, 400 workspace->buf, &out_len); 401 if (ret != LZO_E_OK) { 402 btrfs_err(fs_info, "failed to decompress"); 403 return -EIO; 404 } 405 406 /* Copy the data into inode pages */ 407 ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out); 408 cur_out += out_len; 409 410 /* All data read, exit */ 411 if (ret == 0) 412 return 0; 413 ret = 0; 414 415 /* Check if the sector has enough space for a segment header */ 416 sector_bytes_left = sectorsize - (cur_in % sectorsize); 417 if (sector_bytes_left >= LZO_LEN) 418 continue; 419 420 /* Skip the padding zeros */ 421 cur_in += sector_bytes_left; 422 } 423 424 return 0; 425} 426 427int lzo_decompress(struct list_head *ws, const u8 *data_in, 428 struct page *dest_page, unsigned long dest_pgoff, size_t srclen, 429 size_t destlen) 430{ 431 struct workspace *workspace = list_entry(ws, struct workspace, list); 432 struct btrfs_fs_info *fs_info = page_to_fs_info(dest_page); 433 const u32 sectorsize = fs_info->sectorsize; 434 size_t in_len; 435 size_t out_len; 436 size_t max_segment_len = WORKSPACE_BUF_LENGTH; 437 int ret = 0; 438 439 if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2) 440 return -EUCLEAN; 441 442 in_len = read_compress_length(data_in); 443 if (in_len != srclen) 444 return -EUCLEAN; 445 data_in += LZO_LEN; 446 447 in_len = read_compress_length(data_in); 448 if (in_len != srclen - LZO_LEN * 2) { 449 ret = -EUCLEAN; 450 goto out; 451 } 452 data_in += LZO_LEN; 453 454 out_len = sectorsize; 455 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len); 456 if (ret != LZO_E_OK) { 457 pr_warn("BTRFS: decompress failed!\n"); 458 ret = -EIO; 459 goto out; 460 } 461 462 ASSERT(out_len <= sectorsize); 463 memcpy_to_page(dest_page, dest_pgoff, workspace->buf, out_len); 464 /* Early end, considered as an error. */ 465 if (unlikely(out_len < destlen)) { 466 ret = -EIO; 467 memzero_page(dest_page, dest_pgoff + out_len, destlen - out_len); 468 } 469out: 470 return ret; 471} 472 473const struct btrfs_compress_op btrfs_lzo_compress = { 474 .workspace_manager = &wsm, 475 .max_level = 1, 476 .default_level = 1, 477}; 478