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
64 struct 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
71 static struct workspace_manager wsm;
72
lzo_free_workspace(struct list_head * ws)73 void 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
lzo_alloc_workspace(void)83 struct list_head *lzo_alloc_workspace(void)
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;
100 fail:
101 lzo_free_workspace(&workspace->list);
102 return ERR_PTR(-ENOMEM);
103 }
104
write_compress_length(char * buf,size_t len)105 static 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
read_compress_length(const char * buf)113 static 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 */
copy_compressed_data_to_page(char * compressed_data,size_t compressed_size,struct folio ** out_folios,unsigned long max_nr_folio,u32 * cur_out,const u32 sectorsize)131 static int copy_compressed_data_to_page(char *compressed_data,
132 size_t compressed_size,
133 struct folio **out_folios,
134 unsigned long max_nr_folio,
135 u32 *cur_out,
136 const u32 sectorsize)
137 {
138 u32 sector_bytes_left;
139 u32 orig_out;
140 struct folio *cur_folio;
141 char *kaddr;
142
143 if ((*cur_out / PAGE_SIZE) >= max_nr_folio)
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_folio = out_folios[*cur_out / PAGE_SIZE];
153 /* Allocate a new page */
154 if (!cur_folio) {
155 cur_folio = btrfs_alloc_compr_folio();
156 if (!cur_folio)
157 return -ENOMEM;
158 out_folios[*cur_out / PAGE_SIZE] = cur_folio;
159 }
160
161 kaddr = kmap_local_folio(cur_folio, 0);
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_folio)
176 return -E2BIG;
177
178 cur_folio = out_folios[*cur_out / PAGE_SIZE];
179 /* Allocate a new page */
180 if (!cur_folio) {
181 cur_folio = btrfs_alloc_compr_folio();
182 if (!cur_folio)
183 return -ENOMEM;
184 out_folios[*cur_out / PAGE_SIZE] = cur_folio;
185 }
186 kaddr = kmap_local_folio(cur_folio, 0);
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
207 out:
208 kunmap_local(kaddr);
209 return 0;
210 }
211
lzo_compress_folios(struct list_head * ws,struct address_space * mapping,u64 start,struct folio ** folios,unsigned long * out_folios,unsigned long * total_in,unsigned long * total_out)212 int lzo_compress_folios(struct list_head *ws, struct address_space *mapping,
213 u64 start, struct folio **folios, unsigned long *out_folios,
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 folio *folio_in = NULL;
219 char *sizes_ptr;
220 const unsigned long max_nr_folio = *out_folios;
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_folio > 0);
229 *out_folios = 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 (!folio_in) {
247 ret = btrfs_compress_filemap_get_folio(mapping, cur_in, &folio_in);
248 if (ret < 0)
249 goto out;
250 }
251
252 /* Compress at most one sector of data each time */
253 in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off);
254 ASSERT(in_len);
255 data_in = kmap_local_folio(folio_in, offset_in_folio(folio_in, cur_in));
256 ret = lzo1x_1_compress(data_in, in_len,
257 workspace->cbuf, &out_len,
258 workspace->mem);
259 kunmap_local(data_in);
260 if (unlikely(ret < 0)) {
261 /* lzo1x_1_compress never fails. */
262 ret = -EIO;
263 goto out;
264 }
265
266 ret = copy_compressed_data_to_page(workspace->cbuf, out_len,
267 folios, max_nr_folio,
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 folio_put(folio_in);
286 folio_in = NULL;
287 }
288 }
289
290 /* Store the size of all chunks of compressed data */
291 sizes_ptr = kmap_local_folio(folios[0], 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;
298 out:
299 if (folio_in)
300 folio_put(folio_in);
301 *out_folios = 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 */
copy_compressed_segment(struct compressed_bio * cb,char * dest,u32 len,u32 * cur_in)310 static 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 folio *cur_folio;
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_folio = cb->compressed_folios[*cur_in / PAGE_SIZE];
322
323 memcpy_from_folio(dest + *cur_in - orig_in, cur_folio,
324 offset_in_folio(cur_folio, *cur_in), copy_len);
325
326 *cur_in += copy_len;
327 }
328 }
329
lzo_decompress_bio(struct list_head * ws,struct compressed_bio * cb)330 int 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_folio(cb->compressed_folios[0], 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 (unlikely(len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) ||
357 round_up(len_in, sectorsize) < cb->compressed_len)) {
358 struct btrfs_inode *inode = cb->bbio.inode;
359
360 btrfs_err(fs_info,
361 "lzo header invalid, root %llu inode %llu offset %llu lzo len %u compressed len %u",
362 btrfs_root_id(inode->root), btrfs_ino(inode),
363 cb->start, len_in, cb->compressed_len);
364 return -EUCLEAN;
365 }
366
367 /* Go through each lzo segment */
368 while (cur_in < len_in) {
369 struct folio *cur_folio;
370 /* Length of the compressed segment */
371 u32 seg_len;
372 u32 sector_bytes_left;
373 size_t out_len = lzo1x_worst_compress(sectorsize);
374
375 /*
376 * We should always have enough space for one segment header
377 * inside current sector.
378 */
379 ASSERT(cur_in / sectorsize ==
380 (cur_in + LZO_LEN - 1) / sectorsize);
381 cur_folio = cb->compressed_folios[cur_in / PAGE_SIZE];
382 ASSERT(cur_folio);
383 kaddr = kmap_local_folio(cur_folio, 0);
384 seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
385 kunmap_local(kaddr);
386 cur_in += LZO_LEN;
387
388 if (unlikely(seg_len > WORKSPACE_CBUF_LENGTH)) {
389 struct btrfs_inode *inode = cb->bbio.inode;
390
391 /*
392 * seg_len shouldn't be larger than we have allocated
393 * for workspace->cbuf
394 */
395 btrfs_err(fs_info,
396 "lzo segment too big, root %llu inode %llu offset %llu len %u",
397 btrfs_root_id(inode->root), btrfs_ino(inode),
398 cb->start, seg_len);
399 return -EIO;
400 }
401
402 /* Copy the compressed segment payload into workspace */
403 copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in);
404
405 /* Decompress the data */
406 ret = lzo1x_decompress_safe(workspace->cbuf, seg_len,
407 workspace->buf, &out_len);
408 if (unlikely(ret != LZO_E_OK)) {
409 struct btrfs_inode *inode = cb->bbio.inode;
410
411 btrfs_err(fs_info,
412 "lzo decompression failed, error %d root %llu inode %llu offset %llu",
413 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
414 cb->start);
415 return -EIO;
416 }
417
418 /* Copy the data into inode pages */
419 ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out);
420 cur_out += out_len;
421
422 /* All data read, exit */
423 if (ret == 0)
424 return 0;
425 ret = 0;
426
427 /* Check if the sector has enough space for a segment header */
428 sector_bytes_left = sectorsize - (cur_in % sectorsize);
429 if (sector_bytes_left >= LZO_LEN)
430 continue;
431
432 /* Skip the padding zeros */
433 cur_in += sector_bytes_left;
434 }
435
436 return 0;
437 }
438
lzo_decompress(struct list_head * ws,const u8 * data_in,struct folio * dest_folio,unsigned long dest_pgoff,size_t srclen,size_t destlen)439 int lzo_decompress(struct list_head *ws, const u8 *data_in,
440 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
441 size_t destlen)
442 {
443 struct workspace *workspace = list_entry(ws, struct workspace, list);
444 struct btrfs_fs_info *fs_info = folio_to_fs_info(dest_folio);
445 const u32 sectorsize = fs_info->sectorsize;
446 size_t in_len;
447 size_t out_len;
448 size_t max_segment_len = WORKSPACE_BUF_LENGTH;
449 int ret = 0;
450
451 if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2)
452 return -EUCLEAN;
453
454 in_len = read_compress_length(data_in);
455 if (in_len != srclen)
456 return -EUCLEAN;
457 data_in += LZO_LEN;
458
459 in_len = read_compress_length(data_in);
460 if (in_len != srclen - LZO_LEN * 2) {
461 ret = -EUCLEAN;
462 goto out;
463 }
464 data_in += LZO_LEN;
465
466 out_len = sectorsize;
467 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
468 if (unlikely(ret != LZO_E_OK)) {
469 struct btrfs_inode *inode = folio_to_inode(dest_folio);
470
471 btrfs_err(fs_info,
472 "lzo decompression failed, error %d root %llu inode %llu offset %llu",
473 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
474 folio_pos(dest_folio));
475 ret = -EIO;
476 goto out;
477 }
478
479 ASSERT(out_len <= sectorsize);
480 memcpy_to_folio(dest_folio, dest_pgoff, workspace->buf, out_len);
481 /* Early end, considered as an error. */
482 if (unlikely(out_len < destlen)) {
483 ret = -EIO;
484 folio_zero_range(dest_folio, dest_pgoff + out_len, destlen - out_len);
485 }
486 out:
487 return ret;
488 }
489
490 const struct btrfs_compress_op btrfs_lzo_compress = {
491 .workspace_manager = &wsm,
492 .max_level = 1,
493 .default_level = 1,
494 };
495