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c8b97818 CM |
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> | |
b2950863 | 33 | #include "compression.h" |
c8b97818 CM |
34 | |
35 | /* Plan: call deflate() with avail_in == *sourcelen, | |
36 | avail_out = *dstlen - 12 and flush == Z_FINISH. | |
37 | If it doesn't manage to finish, call it again with | |
38 | avail_in == 0 and avail_out set to the remaining 12 | |
39 | bytes for it to clean up. | |
40 | Q: Is 12 bytes sufficient? | |
41 | */ | |
42 | #define STREAM_END_SPACE 12 | |
43 | ||
44 | struct workspace { | |
45 | z_stream inf_strm; | |
46 | z_stream def_strm; | |
47 | char *buf; | |
48 | struct list_head list; | |
49 | }; | |
50 | ||
51 | static LIST_HEAD(idle_workspace); | |
52 | static DEFINE_SPINLOCK(workspace_lock); | |
53 | static unsigned long num_workspace; | |
54 | static atomic_t alloc_workspace = ATOMIC_INIT(0); | |
55 | static DECLARE_WAIT_QUEUE_HEAD(workspace_wait); | |
56 | ||
57 | /* | |
58 | * this finds an available zlib workspace or allocates a new one | |
59 | * NULL or an ERR_PTR is returned if things go bad. | |
60 | */ | |
61 | static struct workspace *find_zlib_workspace(void) | |
62 | { | |
63 | struct workspace *workspace; | |
64 | int ret; | |
65 | int cpus = num_online_cpus(); | |
66 | ||
67 | again: | |
68 | spin_lock(&workspace_lock); | |
69 | if (!list_empty(&idle_workspace)) { | |
70 | workspace = list_entry(idle_workspace.next, struct workspace, | |
71 | list); | |
72 | list_del(&workspace->list); | |
73 | num_workspace--; | |
74 | spin_unlock(&workspace_lock); | |
75 | return workspace; | |
76 | ||
77 | } | |
78 | spin_unlock(&workspace_lock); | |
79 | if (atomic_read(&alloc_workspace) > cpus) { | |
80 | DEFINE_WAIT(wait); | |
81 | prepare_to_wait(&workspace_wait, &wait, TASK_UNINTERRUPTIBLE); | |
82 | if (atomic_read(&alloc_workspace) > cpus) | |
83 | schedule(); | |
84 | finish_wait(&workspace_wait, &wait); | |
85 | goto again; | |
86 | } | |
87 | atomic_inc(&alloc_workspace); | |
88 | workspace = kzalloc(sizeof(*workspace), GFP_NOFS); | |
89 | if (!workspace) { | |
90 | ret = -ENOMEM; | |
91 | goto fail; | |
92 | } | |
93 | ||
94 | workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize()); | |
95 | if (!workspace->def_strm.workspace) { | |
96 | ret = -ENOMEM; | |
97 | goto fail; | |
98 | } | |
99 | workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize()); | |
100 | if (!workspace->inf_strm.workspace) { | |
101 | ret = -ENOMEM; | |
102 | goto fail_inflate; | |
103 | } | |
104 | workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS); | |
105 | if (!workspace->buf) { | |
106 | ret = -ENOMEM; | |
107 | goto fail_kmalloc; | |
108 | } | |
109 | return workspace; | |
110 | ||
111 | fail_kmalloc: | |
112 | vfree(workspace->inf_strm.workspace); | |
113 | fail_inflate: | |
114 | vfree(workspace->def_strm.workspace); | |
115 | fail: | |
116 | kfree(workspace); | |
117 | atomic_dec(&alloc_workspace); | |
118 | wake_up(&workspace_wait); | |
119 | return ERR_PTR(ret); | |
120 | } | |
121 | ||
122 | /* | |
123 | * put a workspace struct back on the list or free it if we have enough | |
124 | * idle ones sitting around | |
125 | */ | |
126 | static int free_workspace(struct workspace *workspace) | |
127 | { | |
128 | spin_lock(&workspace_lock); | |
129 | if (num_workspace < num_online_cpus()) { | |
130 | list_add_tail(&workspace->list, &idle_workspace); | |
131 | num_workspace++; | |
132 | spin_unlock(&workspace_lock); | |
133 | if (waitqueue_active(&workspace_wait)) | |
134 | wake_up(&workspace_wait); | |
135 | return 0; | |
136 | } | |
137 | spin_unlock(&workspace_lock); | |
138 | vfree(workspace->def_strm.workspace); | |
139 | vfree(workspace->inf_strm.workspace); | |
140 | kfree(workspace->buf); | |
141 | kfree(workspace); | |
142 | ||
143 | atomic_dec(&alloc_workspace); | |
144 | if (waitqueue_active(&workspace_wait)) | |
145 | wake_up(&workspace_wait); | |
146 | return 0; | |
147 | } | |
148 | ||
149 | /* | |
150 | * cleanup function for module exit | |
151 | */ | |
152 | static void free_workspaces(void) | |
153 | { | |
154 | struct workspace *workspace; | |
d397712b | 155 | while (!list_empty(&idle_workspace)) { |
c8b97818 CM |
156 | workspace = list_entry(idle_workspace.next, struct workspace, |
157 | list); | |
158 | list_del(&workspace->list); | |
159 | vfree(workspace->def_strm.workspace); | |
160 | vfree(workspace->inf_strm.workspace); | |
161 | kfree(workspace->buf); | |
162 | kfree(workspace); | |
163 | atomic_dec(&alloc_workspace); | |
164 | } | |
165 | } | |
166 | ||
167 | /* | |
168 | * given an address space and start/len, compress the bytes. | |
169 | * | |
170 | * pages are allocated to hold the compressed result and stored | |
171 | * in 'pages' | |
172 | * | |
173 | * out_pages is used to return the number of pages allocated. There | |
174 | * may be pages allocated even if we return an error | |
175 | * | |
176 | * total_in is used to return the number of bytes actually read. It | |
177 | * may be smaller then len if we had to exit early because we | |
178 | * ran out of room in the pages array or because we cross the | |
179 | * max_out threshold. | |
180 | * | |
181 | * total_out is used to return the total number of compressed bytes | |
182 | * | |
183 | * max_out tells us the max number of bytes that we're allowed to | |
184 | * stuff into pages | |
185 | */ | |
186 | int btrfs_zlib_compress_pages(struct address_space *mapping, | |
187 | u64 start, unsigned long len, | |
188 | struct page **pages, | |
189 | unsigned long nr_dest_pages, | |
190 | unsigned long *out_pages, | |
191 | unsigned long *total_in, | |
192 | unsigned long *total_out, | |
193 | unsigned long max_out) | |
194 | { | |
195 | int ret; | |
196 | struct workspace *workspace; | |
197 | char *data_in; | |
198 | char *cpage_out; | |
199 | int nr_pages = 0; | |
200 | struct page *in_page = NULL; | |
201 | struct page *out_page = NULL; | |
202 | int out_written = 0; | |
203 | int in_read = 0; | |
204 | unsigned long bytes_left; | |
205 | ||
206 | *out_pages = 0; | |
207 | *total_out = 0; | |
208 | *total_in = 0; | |
209 | ||
210 | workspace = find_zlib_workspace(); | |
211 | if (!workspace) | |
212 | return -1; | |
213 | ||
214 | if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) { | |
215 | printk(KERN_WARNING "deflateInit failed\n"); | |
216 | ret = -1; | |
217 | goto out; | |
218 | } | |
219 | ||
220 | workspace->def_strm.total_in = 0; | |
221 | workspace->def_strm.total_out = 0; | |
222 | ||
223 | in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT); | |
224 | data_in = kmap(in_page); | |
225 | ||
226 | out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); | |
227 | cpage_out = kmap(out_page); | |
228 | pages[0] = out_page; | |
229 | nr_pages = 1; | |
230 | ||
231 | workspace->def_strm.next_in = data_in; | |
232 | workspace->def_strm.next_out = cpage_out; | |
233 | workspace->def_strm.avail_out = PAGE_CACHE_SIZE; | |
234 | workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE); | |
235 | ||
236 | out_written = 0; | |
237 | in_read = 0; | |
238 | ||
239 | while (workspace->def_strm.total_in < len) { | |
240 | ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH); | |
241 | if (ret != Z_OK) { | |
242 | printk(KERN_DEBUG "btrfs deflate in loop returned %d\n", | |
243 | ret); | |
244 | zlib_deflateEnd(&workspace->def_strm); | |
245 | ret = -1; | |
246 | goto out; | |
247 | } | |
248 | ||
249 | /* we're making it bigger, give up */ | |
250 | if (workspace->def_strm.total_in > 8192 && | |
251 | workspace->def_strm.total_in < | |
252 | workspace->def_strm.total_out) { | |
253 | ret = -1; | |
254 | goto out; | |
255 | } | |
256 | /* we need another page for writing out. Test this | |
257 | * before the total_in so we will pull in a new page for | |
258 | * the stream end if required | |
259 | */ | |
260 | if (workspace->def_strm.avail_out == 0) { | |
261 | kunmap(out_page); | |
262 | if (nr_pages == nr_dest_pages) { | |
263 | out_page = NULL; | |
264 | ret = -1; | |
265 | goto out; | |
266 | } | |
267 | out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); | |
268 | cpage_out = kmap(out_page); | |
269 | pages[nr_pages] = out_page; | |
270 | nr_pages++; | |
271 | workspace->def_strm.avail_out = PAGE_CACHE_SIZE; | |
272 | workspace->def_strm.next_out = cpage_out; | |
273 | } | |
274 | /* we're all done */ | |
275 | if (workspace->def_strm.total_in >= len) | |
276 | break; | |
277 | ||
278 | /* we've read in a full page, get a new one */ | |
279 | if (workspace->def_strm.avail_in == 0) { | |
280 | if (workspace->def_strm.total_out > max_out) | |
281 | break; | |
282 | ||
283 | bytes_left = len - workspace->def_strm.total_in; | |
284 | kunmap(in_page); | |
285 | page_cache_release(in_page); | |
286 | ||
287 | start += PAGE_CACHE_SIZE; | |
288 | in_page = find_get_page(mapping, | |
289 | start >> PAGE_CACHE_SHIFT); | |
290 | data_in = kmap(in_page); | |
291 | workspace->def_strm.avail_in = min(bytes_left, | |
292 | PAGE_CACHE_SIZE); | |
293 | workspace->def_strm.next_in = data_in; | |
294 | } | |
295 | } | |
296 | workspace->def_strm.avail_in = 0; | |
297 | ret = zlib_deflate(&workspace->def_strm, Z_FINISH); | |
298 | zlib_deflateEnd(&workspace->def_strm); | |
299 | ||
300 | if (ret != Z_STREAM_END) { | |
301 | ret = -1; | |
302 | goto out; | |
303 | } | |
304 | ||
305 | if (workspace->def_strm.total_out >= workspace->def_strm.total_in) { | |
306 | ret = -1; | |
307 | goto out; | |
308 | } | |
309 | ||
310 | ret = 0; | |
311 | *total_out = workspace->def_strm.total_out; | |
312 | *total_in = workspace->def_strm.total_in; | |
313 | out: | |
314 | *out_pages = nr_pages; | |
315 | if (out_page) | |
316 | kunmap(out_page); | |
317 | ||
318 | if (in_page) { | |
319 | kunmap(in_page); | |
320 | page_cache_release(in_page); | |
321 | } | |
322 | free_workspace(workspace); | |
323 | return ret; | |
324 | } | |
325 | ||
326 | /* | |
327 | * pages_in is an array of pages with compressed data. | |
328 | * | |
329 | * disk_start is the starting logical offset of this array in the file | |
330 | * | |
331 | * bvec is a bio_vec of pages from the file that we want to decompress into | |
332 | * | |
333 | * vcnt is the count of pages in the biovec | |
334 | * | |
335 | * srclen is the number of bytes in pages_in | |
336 | * | |
337 | * The basic idea is that we have a bio that was created by readpages. | |
338 | * The pages in the bio are for the uncompressed data, and they may not | |
339 | * be contiguous. They all correspond to the range of bytes covered by | |
340 | * the compressed extent. | |
341 | */ | |
342 | int btrfs_zlib_decompress_biovec(struct page **pages_in, | |
343 | u64 disk_start, | |
344 | struct bio_vec *bvec, | |
345 | int vcnt, | |
346 | size_t srclen) | |
347 | { | |
348 | int ret = 0; | |
349 | int wbits = MAX_WBITS; | |
350 | struct workspace *workspace; | |
351 | char *data_in; | |
352 | size_t total_out = 0; | |
353 | unsigned long page_bytes_left; | |
354 | unsigned long page_in_index = 0; | |
355 | unsigned long page_out_index = 0; | |
356 | struct page *page_out; | |
357 | unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) / | |
358 | PAGE_CACHE_SIZE; | |
359 | unsigned long buf_start; | |
360 | unsigned long buf_offset; | |
361 | unsigned long bytes; | |
362 | unsigned long working_bytes; | |
363 | unsigned long pg_offset; | |
364 | unsigned long start_byte; | |
365 | unsigned long current_buf_start; | |
366 | char *kaddr; | |
367 | ||
368 | workspace = find_zlib_workspace(); | |
369 | if (!workspace) | |
370 | return -ENOMEM; | |
371 | ||
372 | data_in = kmap(pages_in[page_in_index]); | |
373 | workspace->inf_strm.next_in = data_in; | |
5b050f04 | 374 | workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE); |
c8b97818 CM |
375 | workspace->inf_strm.total_in = 0; |
376 | ||
377 | workspace->inf_strm.total_out = 0; | |
378 | workspace->inf_strm.next_out = workspace->buf; | |
379 | workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; | |
380 | page_out = bvec[page_out_index].bv_page; | |
381 | page_bytes_left = PAGE_CACHE_SIZE; | |
382 | pg_offset = 0; | |
383 | ||
384 | /* If it's deflate, and it's got no preset dictionary, then | |
385 | we can tell zlib to skip the adler32 check. */ | |
386 | if (srclen > 2 && !(data_in[1] & PRESET_DICT) && | |
387 | ((data_in[0] & 0x0f) == Z_DEFLATED) && | |
388 | !(((data_in[0]<<8) + data_in[1]) % 31)) { | |
389 | ||
390 | wbits = -((data_in[0] >> 4) + 8); | |
391 | workspace->inf_strm.next_in += 2; | |
392 | workspace->inf_strm.avail_in -= 2; | |
393 | } | |
394 | ||
395 | if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) { | |
396 | printk(KERN_WARNING "inflateInit failed\n"); | |
397 | ret = -1; | |
398 | goto out; | |
399 | } | |
d397712b | 400 | while (workspace->inf_strm.total_in < srclen) { |
c8b97818 | 401 | ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH); |
d397712b | 402 | if (ret != Z_OK && ret != Z_STREAM_END) |
c8b97818 | 403 | break; |
c8b97818 CM |
404 | /* |
405 | * buf start is the byte offset we're of the start of | |
406 | * our workspace buffer | |
407 | */ | |
408 | buf_start = total_out; | |
409 | ||
410 | /* total_out is the last byte of the workspace buffer */ | |
411 | total_out = workspace->inf_strm.total_out; | |
412 | ||
413 | working_bytes = total_out - buf_start; | |
414 | ||
415 | /* | |
416 | * start byte is the first byte of the page we're currently | |
417 | * copying into relative to the start of the compressed data. | |
418 | */ | |
419 | start_byte = page_offset(page_out) - disk_start; | |
420 | ||
421 | if (working_bytes == 0) { | |
422 | /* we didn't make progress in this inflate | |
423 | * call, we're done | |
424 | */ | |
d397712b | 425 | if (ret != Z_STREAM_END) |
c8b97818 CM |
426 | ret = -1; |
427 | break; | |
428 | } | |
429 | ||
430 | /* we haven't yet hit data corresponding to this page */ | |
d397712b | 431 | if (total_out <= start_byte) |
c8b97818 | 432 | goto next; |
c8b97818 CM |
433 | |
434 | /* | |
435 | * the start of the data we care about is offset into | |
436 | * the middle of our working buffer | |
437 | */ | |
438 | if (total_out > start_byte && buf_start < start_byte) { | |
439 | buf_offset = start_byte - buf_start; | |
440 | working_bytes -= buf_offset; | |
441 | } else { | |
442 | buf_offset = 0; | |
443 | } | |
444 | current_buf_start = buf_start; | |
445 | ||
446 | /* copy bytes from the working buffer into the pages */ | |
d397712b | 447 | while (working_bytes > 0) { |
c8b97818 CM |
448 | bytes = min(PAGE_CACHE_SIZE - pg_offset, |
449 | PAGE_CACHE_SIZE - buf_offset); | |
450 | bytes = min(bytes, working_bytes); | |
451 | kaddr = kmap_atomic(page_out, KM_USER0); | |
452 | memcpy(kaddr + pg_offset, workspace->buf + buf_offset, | |
453 | bytes); | |
454 | kunmap_atomic(kaddr, KM_USER0); | |
455 | flush_dcache_page(page_out); | |
456 | ||
457 | pg_offset += bytes; | |
458 | page_bytes_left -= bytes; | |
459 | buf_offset += bytes; | |
460 | working_bytes -= bytes; | |
461 | current_buf_start += bytes; | |
462 | ||
463 | /* check if we need to pick another page */ | |
464 | if (page_bytes_left == 0) { | |
465 | page_out_index++; | |
466 | if (page_out_index >= vcnt) { | |
467 | ret = 0; | |
468 | goto done; | |
469 | } | |
d397712b | 470 | |
c8b97818 CM |
471 | page_out = bvec[page_out_index].bv_page; |
472 | pg_offset = 0; | |
473 | page_bytes_left = PAGE_CACHE_SIZE; | |
474 | start_byte = page_offset(page_out) - disk_start; | |
475 | ||
476 | /* | |
477 | * make sure our new page is covered by this | |
478 | * working buffer | |
479 | */ | |
d397712b | 480 | if (total_out <= start_byte) |
c8b97818 | 481 | goto next; |
c8b97818 CM |
482 | |
483 | /* the next page in the biovec might not | |
484 | * be adjacent to the last page, but it | |
485 | * might still be found inside this working | |
486 | * buffer. bump our offset pointer | |
487 | */ | |
488 | if (total_out > start_byte && | |
489 | current_buf_start < start_byte) { | |
490 | buf_offset = start_byte - buf_start; | |
491 | working_bytes = total_out - start_byte; | |
492 | current_buf_start = buf_start + | |
493 | buf_offset; | |
494 | } | |
495 | } | |
496 | } | |
497 | next: | |
498 | workspace->inf_strm.next_out = workspace->buf; | |
499 | workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; | |
500 | ||
501 | if (workspace->inf_strm.avail_in == 0) { | |
502 | unsigned long tmp; | |
503 | kunmap(pages_in[page_in_index]); | |
504 | page_in_index++; | |
505 | if (page_in_index >= total_pages_in) { | |
506 | data_in = NULL; | |
507 | break; | |
508 | } | |
509 | data_in = kmap(pages_in[page_in_index]); | |
510 | workspace->inf_strm.next_in = data_in; | |
511 | tmp = srclen - workspace->inf_strm.total_in; | |
512 | workspace->inf_strm.avail_in = min(tmp, | |
513 | PAGE_CACHE_SIZE); | |
514 | } | |
515 | } | |
d397712b | 516 | if (ret != Z_STREAM_END) |
c8b97818 | 517 | ret = -1; |
d397712b | 518 | else |
c8b97818 | 519 | ret = 0; |
c8b97818 CM |
520 | done: |
521 | zlib_inflateEnd(&workspace->inf_strm); | |
522 | if (data_in) | |
523 | kunmap(pages_in[page_in_index]); | |
524 | out: | |
525 | free_workspace(workspace); | |
526 | return ret; | |
527 | } | |
528 | ||
529 | /* | |
530 | * a less complex decompression routine. Our compressed data fits in a | |
531 | * single page, and we want to read a single page out of it. | |
532 | * start_byte tells us the offset into the compressed data we're interested in | |
533 | */ | |
534 | int btrfs_zlib_decompress(unsigned char *data_in, | |
535 | struct page *dest_page, | |
536 | unsigned long start_byte, | |
537 | size_t srclen, size_t destlen) | |
538 | { | |
539 | int ret = 0; | |
540 | int wbits = MAX_WBITS; | |
541 | struct workspace *workspace; | |
542 | unsigned long bytes_left = destlen; | |
543 | unsigned long total_out = 0; | |
544 | char *kaddr; | |
545 | ||
546 | if (destlen > PAGE_CACHE_SIZE) | |
547 | return -ENOMEM; | |
548 | ||
549 | workspace = find_zlib_workspace(); | |
550 | if (!workspace) | |
551 | return -ENOMEM; | |
552 | ||
553 | workspace->inf_strm.next_in = data_in; | |
554 | workspace->inf_strm.avail_in = srclen; | |
555 | workspace->inf_strm.total_in = 0; | |
556 | ||
557 | workspace->inf_strm.next_out = workspace->buf; | |
558 | workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; | |
559 | workspace->inf_strm.total_out = 0; | |
560 | /* If it's deflate, and it's got no preset dictionary, then | |
561 | we can tell zlib to skip the adler32 check. */ | |
562 | if (srclen > 2 && !(data_in[1] & PRESET_DICT) && | |
563 | ((data_in[0] & 0x0f) == Z_DEFLATED) && | |
564 | !(((data_in[0]<<8) + data_in[1]) % 31)) { | |
565 | ||
566 | wbits = -((data_in[0] >> 4) + 8); | |
567 | workspace->inf_strm.next_in += 2; | |
568 | workspace->inf_strm.avail_in -= 2; | |
569 | } | |
570 | ||
571 | if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) { | |
572 | printk(KERN_WARNING "inflateInit failed\n"); | |
573 | ret = -1; | |
574 | goto out; | |
575 | } | |
576 | ||
d397712b | 577 | while (bytes_left > 0) { |
c8b97818 CM |
578 | unsigned long buf_start; |
579 | unsigned long buf_offset; | |
580 | unsigned long bytes; | |
581 | unsigned long pg_offset = 0; | |
582 | ||
583 | ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH); | |
d397712b | 584 | if (ret != Z_OK && ret != Z_STREAM_END) |
c8b97818 | 585 | break; |
c8b97818 CM |
586 | |
587 | buf_start = total_out; | |
588 | total_out = workspace->inf_strm.total_out; | |
589 | ||
590 | if (total_out == buf_start) { | |
591 | ret = -1; | |
592 | break; | |
593 | } | |
594 | ||
d397712b | 595 | if (total_out <= start_byte) |
c8b97818 | 596 | goto next; |
c8b97818 | 597 | |
d397712b | 598 | if (total_out > start_byte && buf_start < start_byte) |
c8b97818 | 599 | buf_offset = start_byte - buf_start; |
d397712b | 600 | else |
c8b97818 | 601 | buf_offset = 0; |
c8b97818 CM |
602 | |
603 | bytes = min(PAGE_CACHE_SIZE - pg_offset, | |
604 | PAGE_CACHE_SIZE - buf_offset); | |
605 | bytes = min(bytes, bytes_left); | |
606 | ||
607 | kaddr = kmap_atomic(dest_page, KM_USER0); | |
608 | memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes); | |
609 | kunmap_atomic(kaddr, KM_USER0); | |
610 | ||
611 | pg_offset += bytes; | |
612 | bytes_left -= bytes; | |
613 | next: | |
614 | workspace->inf_strm.next_out = workspace->buf; | |
615 | workspace->inf_strm.avail_out = PAGE_CACHE_SIZE; | |
616 | } | |
d397712b CM |
617 | |
618 | if (ret != Z_STREAM_END && bytes_left != 0) | |
c8b97818 | 619 | ret = -1; |
d397712b | 620 | else |
c8b97818 | 621 | ret = 0; |
d397712b | 622 | |
c8b97818 CM |
623 | zlib_inflateEnd(&workspace->inf_strm); |
624 | out: | |
625 | free_workspace(workspace); | |
626 | return ret; | |
627 | } | |
628 | ||
629 | void btrfs_zlib_exit(void) | |
630 | { | |
631 | free_workspaces(); | |
632 | } |