Loading...
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(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;
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 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
207out:
208 kunmap_local(kaddr);
209 return 0;
210}
211
212int 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, 0);
256 ret = lzo1x_1_compress(data_in +
257 offset_in_page(cur_in), in_len,
258 workspace->cbuf, &out_len,
259 workspace->mem);
260 kunmap_local(data_in);
261 if (unlikely(ret < 0)) {
262 /* lzo1x_1_compress never fails. */
263 ret = -EIO;
264 goto out;
265 }
266
267 ret = copy_compressed_data_to_page(workspace->cbuf, out_len,
268 folios, max_nr_folio,
269 &cur_out, sectorsize);
270 if (ret < 0)
271 goto out;
272
273 cur_in += in_len;
274
275 /*
276 * Check if we're making it bigger after two sectors. And if
277 * it is so, give up.
278 */
279 if (cur_in - start > sectorsize * 2 && cur_in - start < cur_out) {
280 ret = -E2BIG;
281 goto out;
282 }
283
284 /* Check if we have reached page boundary */
285 if (PAGE_ALIGNED(cur_in)) {
286 folio_put(folio_in);
287 folio_in = NULL;
288 }
289 }
290
291 /* Store the size of all chunks of compressed data */
292 sizes_ptr = kmap_local_folio(folios[0], 0);
293 write_compress_length(sizes_ptr, cur_out);
294 kunmap_local(sizes_ptr);
295
296 ret = 0;
297 *total_out = cur_out;
298 *total_in = cur_in - start;
299out:
300 if (folio_in)
301 folio_put(folio_in);
302 *out_folios = DIV_ROUND_UP(cur_out, PAGE_SIZE);
303 return ret;
304}
305
306/*
307 * Copy the compressed segment payload into @dest.
308 *
309 * For the payload there will be no padding, just need to do page switching.
310 */
311static void copy_compressed_segment(struct compressed_bio *cb,
312 char *dest, u32 len, u32 *cur_in)
313{
314 u32 orig_in = *cur_in;
315
316 while (*cur_in < orig_in + len) {
317 struct folio *cur_folio;
318 u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
319 orig_in + len - *cur_in);
320
321 ASSERT(copy_len);
322 cur_folio = cb->compressed_folios[*cur_in / PAGE_SIZE];
323
324 memcpy_from_folio(dest + *cur_in - orig_in, cur_folio,
325 offset_in_folio(cur_folio, *cur_in), copy_len);
326
327 *cur_in += copy_len;
328 }
329}
330
331int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
332{
333 struct workspace *workspace = list_entry(ws, struct workspace, list);
334 const struct btrfs_fs_info *fs_info = cb->bbio.inode->root->fs_info;
335 const u32 sectorsize = fs_info->sectorsize;
336 char *kaddr;
337 int ret;
338 /* Compressed data length, can be unaligned */
339 u32 len_in;
340 /* Offset inside the compressed data */
341 u32 cur_in = 0;
342 /* Bytes decompressed so far */
343 u32 cur_out = 0;
344
345 kaddr = kmap_local_folio(cb->compressed_folios[0], 0);
346 len_in = read_compress_length(kaddr);
347 kunmap_local(kaddr);
348 cur_in += LZO_LEN;
349
350 /*
351 * LZO header length check
352 *
353 * The total length should not exceed the maximum extent length,
354 * and all sectors should be used.
355 * If this happens, it means the compressed extent is corrupted.
356 */
357 if (unlikely(len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) ||
358 round_up(len_in, sectorsize) < cb->compressed_len)) {
359 struct btrfs_inode *inode = cb->bbio.inode;
360
361 btrfs_err(fs_info,
362"lzo header invalid, root %llu inode %llu offset %llu lzo len %u compressed len %u",
363 btrfs_root_id(inode->root), btrfs_ino(inode),
364 cb->start, len_in, cb->compressed_len);
365 return -EUCLEAN;
366 }
367
368 /* Go through each lzo segment */
369 while (cur_in < len_in) {
370 struct folio *cur_folio;
371 /* Length of the compressed segment */
372 u32 seg_len;
373 u32 sector_bytes_left;
374 size_t out_len = lzo1x_worst_compress(sectorsize);
375
376 /*
377 * We should always have enough space for one segment header
378 * inside current sector.
379 */
380 ASSERT(cur_in / sectorsize ==
381 (cur_in + LZO_LEN - 1) / sectorsize);
382 cur_folio = cb->compressed_folios[cur_in / PAGE_SIZE];
383 ASSERT(cur_folio);
384 kaddr = kmap_local_folio(cur_folio, 0);
385 seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
386 kunmap_local(kaddr);
387 cur_in += LZO_LEN;
388
389 if (unlikely(seg_len > WORKSPACE_CBUF_LENGTH)) {
390 struct btrfs_inode *inode = cb->bbio.inode;
391
392 /*
393 * seg_len shouldn't be larger than we have allocated
394 * for workspace->cbuf
395 */
396 btrfs_err(fs_info,
397 "lzo segment too big, root %llu inode %llu offset %llu len %u",
398 btrfs_root_id(inode->root), btrfs_ino(inode),
399 cb->start, seg_len);
400 return -EIO;
401 }
402
403 /* Copy the compressed segment payload into workspace */
404 copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in);
405
406 /* Decompress the data */
407 ret = lzo1x_decompress_safe(workspace->cbuf, seg_len,
408 workspace->buf, &out_len);
409 if (unlikely(ret != LZO_E_OK)) {
410 struct btrfs_inode *inode = cb->bbio.inode;
411
412 btrfs_err(fs_info,
413 "lzo decompression failed, error %d root %llu inode %llu offset %llu",
414 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
415 cb->start);
416 return -EIO;
417 }
418
419 /* Copy the data into inode pages */
420 ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out);
421 cur_out += out_len;
422
423 /* All data read, exit */
424 if (ret == 0)
425 return 0;
426 ret = 0;
427
428 /* Check if the sector has enough space for a segment header */
429 sector_bytes_left = sectorsize - (cur_in % sectorsize);
430 if (sector_bytes_left >= LZO_LEN)
431 continue;
432
433 /* Skip the padding zeros */
434 cur_in += sector_bytes_left;
435 }
436
437 return 0;
438}
439
440int lzo_decompress(struct list_head *ws, const u8 *data_in,
441 struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
442 size_t destlen)
443{
444 struct workspace *workspace = list_entry(ws, struct workspace, list);
445 struct btrfs_fs_info *fs_info = folio_to_fs_info(dest_folio);
446 const u32 sectorsize = fs_info->sectorsize;
447 size_t in_len;
448 size_t out_len;
449 size_t max_segment_len = WORKSPACE_BUF_LENGTH;
450 int ret = 0;
451
452 if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2)
453 return -EUCLEAN;
454
455 in_len = read_compress_length(data_in);
456 if (in_len != srclen)
457 return -EUCLEAN;
458 data_in += LZO_LEN;
459
460 in_len = read_compress_length(data_in);
461 if (in_len != srclen - LZO_LEN * 2) {
462 ret = -EUCLEAN;
463 goto out;
464 }
465 data_in += LZO_LEN;
466
467 out_len = sectorsize;
468 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
469 if (unlikely(ret != LZO_E_OK)) {
470 struct btrfs_inode *inode = folio_to_inode(dest_folio);
471
472 btrfs_err(fs_info,
473 "lzo decompression failed, error %d root %llu inode %llu offset %llu",
474 ret, btrfs_root_id(inode->root), btrfs_ino(inode),
475 folio_pos(dest_folio));
476 ret = -EIO;
477 goto out;
478 }
479
480 ASSERT(out_len <= sectorsize);
481 memcpy_to_folio(dest_folio, dest_pgoff, workspace->buf, out_len);
482 /* Early end, considered as an error. */
483 if (unlikely(out_len < destlen)) {
484 ret = -EIO;
485 folio_zero_range(dest_folio, dest_pgoff + out_len, destlen - out_len);
486 }
487out:
488 return ret;
489}
490
491const struct btrfs_compress_op btrfs_lzo_compress = {
492 .workspace_manager = &wsm,
493 .max_level = 1,
494 .default_level = 1,
495};
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 "compression.h"
17
18#define LZO_LEN 4
19
20struct workspace {
21 void *mem;
22 void *buf; /* where decompressed data goes */
23 void *cbuf; /* where compressed data goes */
24 struct list_head list;
25};
26
27static void lzo_free_workspace(struct list_head *ws)
28{
29 struct workspace *workspace = list_entry(ws, struct workspace, list);
30
31 kvfree(workspace->buf);
32 kvfree(workspace->cbuf);
33 kvfree(workspace->mem);
34 kfree(workspace);
35}
36
37static struct list_head *lzo_alloc_workspace(void)
38{
39 struct workspace *workspace;
40
41 workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
42 if (!workspace)
43 return ERR_PTR(-ENOMEM);
44
45 workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
46 workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
47 workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
48 if (!workspace->mem || !workspace->buf || !workspace->cbuf)
49 goto fail;
50
51 INIT_LIST_HEAD(&workspace->list);
52
53 return &workspace->list;
54fail:
55 lzo_free_workspace(&workspace->list);
56 return ERR_PTR(-ENOMEM);
57}
58
59static inline void write_compress_length(char *buf, size_t len)
60{
61 __le32 dlen;
62
63 dlen = cpu_to_le32(len);
64 memcpy(buf, &dlen, LZO_LEN);
65}
66
67static inline size_t read_compress_length(const char *buf)
68{
69 __le32 dlen;
70
71 memcpy(&dlen, buf, LZO_LEN);
72 return le32_to_cpu(dlen);
73}
74
75static int lzo_compress_pages(struct list_head *ws,
76 struct address_space *mapping,
77 u64 start,
78 struct page **pages,
79 unsigned long *out_pages,
80 unsigned long *total_in,
81 unsigned long *total_out)
82{
83 struct workspace *workspace = list_entry(ws, struct workspace, list);
84 int ret = 0;
85 char *data_in;
86 char *cpage_out;
87 int nr_pages = 0;
88 struct page *in_page = NULL;
89 struct page *out_page = NULL;
90 unsigned long bytes_left;
91 unsigned long len = *total_out;
92 unsigned long nr_dest_pages = *out_pages;
93 const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
94 size_t in_len;
95 size_t out_len;
96 char *buf;
97 unsigned long tot_in = 0;
98 unsigned long tot_out = 0;
99 unsigned long pg_bytes_left;
100 unsigned long out_offset;
101 unsigned long bytes;
102
103 *out_pages = 0;
104 *total_out = 0;
105 *total_in = 0;
106
107 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
108 data_in = kmap(in_page);
109
110 /*
111 * store the size of all chunks of compressed data in
112 * the first 4 bytes
113 */
114 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
115 if (out_page == NULL) {
116 ret = -ENOMEM;
117 goto out;
118 }
119 cpage_out = kmap(out_page);
120 out_offset = LZO_LEN;
121 tot_out = LZO_LEN;
122 pages[0] = out_page;
123 nr_pages = 1;
124 pg_bytes_left = PAGE_SIZE - LZO_LEN;
125
126 /* compress at most one page of data each time */
127 in_len = min(len, PAGE_SIZE);
128 while (tot_in < len) {
129 ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
130 &out_len, workspace->mem);
131 if (ret != LZO_E_OK) {
132 pr_debug("BTRFS: lzo in loop returned %d\n",
133 ret);
134 ret = -EIO;
135 goto out;
136 }
137
138 /* store the size of this chunk of compressed data */
139 write_compress_length(cpage_out + out_offset, out_len);
140 tot_out += LZO_LEN;
141 out_offset += LZO_LEN;
142 pg_bytes_left -= LZO_LEN;
143
144 tot_in += in_len;
145 tot_out += out_len;
146
147 /* copy bytes from the working buffer into the pages */
148 buf = workspace->cbuf;
149 while (out_len) {
150 bytes = min_t(unsigned long, pg_bytes_left, out_len);
151
152 memcpy(cpage_out + out_offset, buf, bytes);
153
154 out_len -= bytes;
155 pg_bytes_left -= bytes;
156 buf += bytes;
157 out_offset += bytes;
158
159 /*
160 * we need another page for writing out.
161 *
162 * Note if there's less than 4 bytes left, we just
163 * skip to a new page.
164 */
165 if ((out_len == 0 && pg_bytes_left < LZO_LEN) ||
166 pg_bytes_left == 0) {
167 if (pg_bytes_left) {
168 memset(cpage_out + out_offset, 0,
169 pg_bytes_left);
170 tot_out += pg_bytes_left;
171 }
172
173 /* we're done, don't allocate new page */
174 if (out_len == 0 && tot_in >= len)
175 break;
176
177 kunmap(out_page);
178 if (nr_pages == nr_dest_pages) {
179 out_page = NULL;
180 ret = -E2BIG;
181 goto out;
182 }
183
184 out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
185 if (out_page == NULL) {
186 ret = -ENOMEM;
187 goto out;
188 }
189 cpage_out = kmap(out_page);
190 pages[nr_pages++] = out_page;
191
192 pg_bytes_left = PAGE_SIZE;
193 out_offset = 0;
194 }
195 }
196
197 /* we're making it bigger, give up */
198 if (tot_in > 8192 && tot_in < tot_out) {
199 ret = -E2BIG;
200 goto out;
201 }
202
203 /* we're all done */
204 if (tot_in >= len)
205 break;
206
207 if (tot_out > max_out)
208 break;
209
210 bytes_left = len - tot_in;
211 kunmap(in_page);
212 put_page(in_page);
213
214 start += PAGE_SIZE;
215 in_page = find_get_page(mapping, start >> PAGE_SHIFT);
216 data_in = kmap(in_page);
217 in_len = min(bytes_left, PAGE_SIZE);
218 }
219
220 if (tot_out >= tot_in) {
221 ret = -E2BIG;
222 goto out;
223 }
224
225 /* store the size of all chunks of compressed data */
226 cpage_out = kmap(pages[0]);
227 write_compress_length(cpage_out, tot_out);
228
229 kunmap(pages[0]);
230
231 ret = 0;
232 *total_out = tot_out;
233 *total_in = tot_in;
234out:
235 *out_pages = nr_pages;
236 if (out_page)
237 kunmap(out_page);
238
239 if (in_page) {
240 kunmap(in_page);
241 put_page(in_page);
242 }
243
244 return ret;
245}
246
247static int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
248{
249 struct workspace *workspace = list_entry(ws, struct workspace, list);
250 int ret = 0, ret2;
251 char *data_in;
252 unsigned long page_in_index = 0;
253 size_t srclen = cb->compressed_len;
254 unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
255 unsigned long buf_start;
256 unsigned long buf_offset = 0;
257 unsigned long bytes;
258 unsigned long working_bytes;
259 size_t in_len;
260 size_t out_len;
261 unsigned long in_offset;
262 unsigned long in_page_bytes_left;
263 unsigned long tot_in;
264 unsigned long tot_out;
265 unsigned long tot_len;
266 char *buf;
267 bool may_late_unmap, need_unmap;
268 struct page **pages_in = cb->compressed_pages;
269 u64 disk_start = cb->start;
270 struct bio *orig_bio = cb->orig_bio;
271
272 data_in = kmap(pages_in[0]);
273 tot_len = read_compress_length(data_in);
274
275 tot_in = LZO_LEN;
276 in_offset = LZO_LEN;
277 tot_len = min_t(size_t, srclen, tot_len);
278 in_page_bytes_left = PAGE_SIZE - LZO_LEN;
279
280 tot_out = 0;
281
282 while (tot_in < tot_len) {
283 in_len = read_compress_length(data_in + in_offset);
284 in_page_bytes_left -= LZO_LEN;
285 in_offset += LZO_LEN;
286 tot_in += LZO_LEN;
287
288 tot_in += in_len;
289 working_bytes = in_len;
290 may_late_unmap = need_unmap = false;
291
292 /* fast path: avoid using the working buffer */
293 if (in_page_bytes_left >= in_len) {
294 buf = data_in + in_offset;
295 bytes = in_len;
296 may_late_unmap = true;
297 goto cont;
298 }
299
300 /* copy bytes from the pages into the working buffer */
301 buf = workspace->cbuf;
302 buf_offset = 0;
303 while (working_bytes) {
304 bytes = min(working_bytes, in_page_bytes_left);
305
306 memcpy(buf + buf_offset, data_in + in_offset, bytes);
307 buf_offset += bytes;
308cont:
309 working_bytes -= bytes;
310 in_page_bytes_left -= bytes;
311 in_offset += bytes;
312
313 /* check if we need to pick another page */
314 if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
315 || in_page_bytes_left == 0) {
316 tot_in += in_page_bytes_left;
317
318 if (working_bytes == 0 && tot_in >= tot_len)
319 break;
320
321 if (page_in_index + 1 >= total_pages_in) {
322 ret = -EIO;
323 goto done;
324 }
325
326 if (may_late_unmap)
327 need_unmap = true;
328 else
329 kunmap(pages_in[page_in_index]);
330
331 data_in = kmap(pages_in[++page_in_index]);
332
333 in_page_bytes_left = PAGE_SIZE;
334 in_offset = 0;
335 }
336 }
337
338 out_len = lzo1x_worst_compress(PAGE_SIZE);
339 ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
340 &out_len);
341 if (need_unmap)
342 kunmap(pages_in[page_in_index - 1]);
343 if (ret != LZO_E_OK) {
344 pr_warn("BTRFS: decompress failed\n");
345 ret = -EIO;
346 break;
347 }
348
349 buf_start = tot_out;
350 tot_out += out_len;
351
352 ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
353 tot_out, disk_start, orig_bio);
354 if (ret2 == 0)
355 break;
356 }
357done:
358 kunmap(pages_in[page_in_index]);
359 if (!ret)
360 zero_fill_bio(orig_bio);
361 return ret;
362}
363
364static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
365 struct page *dest_page,
366 unsigned long start_byte,
367 size_t srclen, size_t destlen)
368{
369 struct workspace *workspace = list_entry(ws, struct workspace, list);
370 size_t in_len;
371 size_t out_len;
372 int ret = 0;
373 char *kaddr;
374 unsigned long bytes;
375
376 BUG_ON(srclen < LZO_LEN);
377
378 data_in += LZO_LEN;
379
380 in_len = read_compress_length(data_in);
381 data_in += LZO_LEN;
382
383 out_len = PAGE_SIZE;
384 ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
385 if (ret != LZO_E_OK) {
386 pr_warn("BTRFS: decompress failed!\n");
387 ret = -EIO;
388 goto out;
389 }
390
391 if (out_len < start_byte) {
392 ret = -EIO;
393 goto out;
394 }
395
396 /*
397 * the caller is already checking against PAGE_SIZE, but lets
398 * move this check closer to the memcpy/memset
399 */
400 destlen = min_t(unsigned long, destlen, PAGE_SIZE);
401 bytes = min_t(unsigned long, destlen, out_len - start_byte);
402
403 kaddr = kmap_atomic(dest_page);
404 memcpy(kaddr, workspace->buf + start_byte, bytes);
405
406 /*
407 * btrfs_getblock is doing a zero on the tail of the page too,
408 * but this will cover anything missing from the decompressed
409 * data.
410 */
411 if (bytes < destlen)
412 memset(kaddr+bytes, 0, destlen-bytes);
413 kunmap_atomic(kaddr);
414out:
415 return ret;
416}
417
418static void lzo_set_level(struct list_head *ws, unsigned int type)
419{
420}
421
422const struct btrfs_compress_op btrfs_lzo_compress = {
423 .alloc_workspace = lzo_alloc_workspace,
424 .free_workspace = lzo_free_workspace,
425 .compress_pages = lzo_compress_pages,
426 .decompress_bio = lzo_decompress_bio,
427 .decompress = lzo_decompress,
428 .set_level = lzo_set_level,
429};