Line data Source code
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 inf_strm;
37 : z_stream def_strm;
38 : char *buf;
39 : struct list_head list;
40 : };
41 :
42 0 : static void zlib_free_workspace(struct list_head *ws)
43 : {
44 0 : struct workspace *workspace = list_entry(ws, struct workspace, list);
45 :
46 0 : vfree(workspace->def_strm.workspace);
47 0 : vfree(workspace->inf_strm.workspace);
48 0 : kfree(workspace->buf);
49 0 : kfree(workspace);
50 0 : }
51 :
52 0 : static struct list_head *zlib_alloc_workspace(void)
53 : {
54 : struct workspace *workspace;
55 :
56 0 : workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
57 0 : if (!workspace)
58 : return ERR_PTR(-ENOMEM);
59 :
60 0 : workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize(
61 : MAX_WBITS, MAX_MEM_LEVEL));
62 0 : workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
63 0 : workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
64 0 : if (!workspace->def_strm.workspace ||
65 0 : !workspace->inf_strm.workspace || !workspace->buf)
66 : goto fail;
67 :
68 0 : INIT_LIST_HEAD(&workspace->list);
69 :
70 0 : return &workspace->list;
71 : fail:
72 0 : zlib_free_workspace(&workspace->list);
73 0 : return ERR_PTR(-ENOMEM);
74 : }
75 :
76 30 : static int zlib_compress_pages(struct list_head *ws,
77 : struct address_space *mapping,
78 : u64 start, unsigned long len,
79 : struct page **pages,
80 : unsigned long nr_dest_pages,
81 : unsigned long *out_pages,
82 : unsigned long *total_in,
83 : unsigned long *total_out,
84 : unsigned long max_out)
85 : {
86 : struct workspace *workspace = list_entry(ws, struct workspace, list);
87 : int ret;
88 : char *data_in;
89 : char *cpage_out;
90 : int nr_pages = 0;
91 : struct page *in_page = NULL;
92 : struct page *out_page = NULL;
93 : unsigned long bytes_left;
94 :
95 30 : *out_pages = 0;
96 30 : *total_out = 0;
97 30 : *total_in = 0;
98 :
99 30 : if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
100 0 : printk(KERN_WARNING "BTRFS: deflateInit failed\n");
101 : ret = -EIO;
102 0 : goto out;
103 : }
104 :
105 30 : workspace->def_strm.total_in = 0;
106 30 : workspace->def_strm.total_out = 0;
107 :
108 30 : in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
109 : data_in = kmap(in_page);
110 :
111 : out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
112 30 : if (out_page == NULL) {
113 : ret = -ENOMEM;
114 : goto out;
115 : }
116 : cpage_out = kmap(out_page);
117 30 : pages[0] = out_page;
118 : nr_pages = 1;
119 :
120 30 : workspace->def_strm.next_in = data_in;
121 30 : workspace->def_strm.next_out = cpage_out;
122 30 : workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
123 30 : workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
124 :
125 966 : while (workspace->def_strm.total_in < len) {
126 936 : ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
127 938 : if (ret != Z_OK) {
128 0 : printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
129 : ret);
130 0 : zlib_deflateEnd(&workspace->def_strm);
131 : ret = -EIO;
132 0 : goto out;
133 : }
134 :
135 : /* we're making it bigger, give up */
136 1816 : if (workspace->def_strm.total_in > 8192 &&
137 : workspace->def_strm.total_in <
138 878 : workspace->def_strm.total_out) {
139 : ret = -E2BIG;
140 : goto out;
141 : }
142 : /* we need another page for writing out. Test this
143 : * before the total_in so we will pull in a new page for
144 : * the stream end if required
145 : */
146 938 : if (workspace->def_strm.avail_out == 0) {
147 : kunmap(out_page);
148 0 : if (nr_pages == nr_dest_pages) {
149 : out_page = NULL;
150 : ret = -E2BIG;
151 : goto out;
152 : }
153 : out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
154 0 : if (out_page == NULL) {
155 : ret = -ENOMEM;
156 : goto out;
157 : }
158 : cpage_out = kmap(out_page);
159 0 : pages[nr_pages] = out_page;
160 0 : nr_pages++;
161 0 : workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
162 0 : workspace->def_strm.next_out = cpage_out;
163 : }
164 : /* we're all done */
165 938 : if (workspace->def_strm.total_in >= len)
166 : break;
167 :
168 : /* we've read in a full page, get a new one */
169 908 : if (workspace->def_strm.avail_in == 0) {
170 908 : if (workspace->def_strm.total_out > max_out)
171 : break;
172 :
173 908 : bytes_left = len - workspace->def_strm.total_in;
174 : kunmap(in_page);
175 908 : page_cache_release(in_page);
176 :
177 908 : start += PAGE_CACHE_SIZE;
178 : in_page = find_get_page(mapping,
179 908 : start >> PAGE_CACHE_SHIFT);
180 : data_in = kmap(in_page);
181 906 : workspace->def_strm.avail_in = min(bytes_left,
182 : PAGE_CACHE_SIZE);
183 906 : workspace->def_strm.next_in = data_in;
184 : }
185 : }
186 30 : workspace->def_strm.avail_in = 0;
187 30 : ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
188 30 : zlib_deflateEnd(&workspace->def_strm);
189 :
190 30 : if (ret != Z_STREAM_END) {
191 : ret = -EIO;
192 : goto out;
193 : }
194 :
195 30 : if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
196 : ret = -E2BIG;
197 : goto out;
198 : }
199 :
200 : ret = 0;
201 30 : *total_out = workspace->def_strm.total_out;
202 30 : *total_in = workspace->def_strm.total_in;
203 : out:
204 30 : *out_pages = nr_pages;
205 : if (out_page)
206 : kunmap(out_page);
207 :
208 30 : if (in_page) {
209 : kunmap(in_page);
210 30 : page_cache_release(in_page);
211 : }
212 30 : return ret;
213 : }
214 :
215 4 : static int zlib_decompress_biovec(struct list_head *ws, struct page **pages_in,
216 : u64 disk_start,
217 : struct bio_vec *bvec,
218 : int vcnt,
219 : size_t srclen)
220 : {
221 : struct workspace *workspace = list_entry(ws, struct workspace, list);
222 : int ret = 0, ret2;
223 : int wbits = MAX_WBITS;
224 : char *data_in;
225 : size_t total_out = 0;
226 : unsigned long page_in_index = 0;
227 4 : unsigned long page_out_index = 0;
228 4 : unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
229 : PAGE_CACHE_SIZE;
230 : unsigned long buf_start;
231 : unsigned long pg_offset;
232 :
233 4 : data_in = kmap(pages_in[page_in_index]);
234 4 : workspace->inf_strm.next_in = data_in;
235 4 : workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
236 4 : workspace->inf_strm.total_in = 0;
237 :
238 4 : workspace->inf_strm.total_out = 0;
239 4 : workspace->inf_strm.next_out = workspace->buf;
240 4 : workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
241 4 : pg_offset = 0;
242 :
243 : /* If it's deflate, and it's got no preset dictionary, then
244 : we can tell zlib to skip the adler32 check. */
245 8 : if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
246 8 : ((data_in[0] & 0x0f) == Z_DEFLATED) &&
247 4 : !(((data_in[0]<<8) + data_in[1]) % 31)) {
248 :
249 4 : wbits = -((data_in[0] >> 4) + 8);
250 4 : workspace->inf_strm.next_in += 2;
251 4 : workspace->inf_strm.avail_in -= 2;
252 : }
253 :
254 4 : if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
255 0 : printk(KERN_WARNING "BTRFS: inflateInit failed\n");
256 0 : return -EIO;
257 : }
258 120 : while (workspace->inf_strm.total_in < srclen) {
259 120 : ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
260 120 : if (ret != Z_OK && ret != Z_STREAM_END)
261 : break;
262 :
263 : buf_start = total_out;
264 120 : total_out = workspace->inf_strm.total_out;
265 :
266 : /* we didn't make progress in this inflate call, we're done */
267 120 : if (buf_start == total_out)
268 : break;
269 :
270 120 : ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
271 : total_out, disk_start,
272 : bvec, vcnt,
273 : &page_out_index, &pg_offset);
274 120 : if (ret2 == 0) {
275 : ret = 0;
276 : goto done;
277 : }
278 :
279 116 : workspace->inf_strm.next_out = workspace->buf;
280 116 : workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
281 :
282 116 : if (workspace->inf_strm.avail_in == 0) {
283 : unsigned long tmp;
284 : kunmap(pages_in[page_in_index]);
285 0 : page_in_index++;
286 0 : if (page_in_index >= total_pages_in) {
287 : data_in = NULL;
288 : break;
289 : }
290 0 : data_in = kmap(pages_in[page_in_index]);
291 0 : workspace->inf_strm.next_in = data_in;
292 0 : tmp = srclen - workspace->inf_strm.total_in;
293 0 : workspace->inf_strm.avail_in = min(tmp,
294 : PAGE_CACHE_SIZE);
295 : }
296 : }
297 0 : if (ret != Z_STREAM_END)
298 : ret = -EIO;
299 : else
300 : ret = 0;
301 : done:
302 4 : zlib_inflateEnd(&workspace->inf_strm);
303 : if (data_in)
304 : kunmap(pages_in[page_in_index]);
305 4 : return ret;
306 : }
307 :
308 0 : static int zlib_decompress(struct list_head *ws, unsigned char *data_in,
309 : struct page *dest_page,
310 : unsigned long start_byte,
311 : size_t srclen, size_t destlen)
312 : {
313 : struct workspace *workspace = list_entry(ws, struct workspace, list);
314 : int ret = 0;
315 : int wbits = MAX_WBITS;
316 : unsigned long bytes_left = destlen;
317 : unsigned long total_out = 0;
318 : char *kaddr;
319 :
320 0 : workspace->inf_strm.next_in = data_in;
321 0 : workspace->inf_strm.avail_in = srclen;
322 0 : workspace->inf_strm.total_in = 0;
323 :
324 0 : workspace->inf_strm.next_out = workspace->buf;
325 0 : workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
326 0 : workspace->inf_strm.total_out = 0;
327 : /* If it's deflate, and it's got no preset dictionary, then
328 : we can tell zlib to skip the adler32 check. */
329 0 : if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
330 0 : ((data_in[0] & 0x0f) == Z_DEFLATED) &&
331 0 : !(((data_in[0]<<8) + data_in[1]) % 31)) {
332 :
333 0 : wbits = -((data_in[0] >> 4) + 8);
334 0 : workspace->inf_strm.next_in += 2;
335 0 : workspace->inf_strm.avail_in -= 2;
336 : }
337 :
338 0 : if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
339 0 : printk(KERN_WARNING "BTRFS: inflateInit failed\n");
340 0 : return -EIO;
341 : }
342 :
343 0 : while (bytes_left > 0) {
344 : unsigned long buf_start;
345 : unsigned long buf_offset;
346 : unsigned long bytes;
347 : unsigned long pg_offset = 0;
348 :
349 0 : ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
350 0 : if (ret != Z_OK && ret != Z_STREAM_END)
351 : break;
352 :
353 : buf_start = total_out;
354 0 : total_out = workspace->inf_strm.total_out;
355 :
356 0 : if (total_out == buf_start) {
357 : ret = -EIO;
358 : break;
359 : }
360 :
361 0 : if (total_out <= start_byte)
362 : goto next;
363 :
364 0 : if (total_out > start_byte && buf_start < start_byte)
365 0 : buf_offset = start_byte - buf_start;
366 : else
367 : buf_offset = 0;
368 :
369 0 : bytes = min(PAGE_CACHE_SIZE - pg_offset,
370 : PAGE_CACHE_SIZE - buf_offset);
371 0 : bytes = min(bytes, bytes_left);
372 :
373 : kaddr = kmap_atomic(dest_page);
374 0 : memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
375 : kunmap_atomic(kaddr);
376 :
377 : pg_offset += bytes;
378 0 : bytes_left -= bytes;
379 : next:
380 0 : workspace->inf_strm.next_out = workspace->buf;
381 0 : workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
382 : }
383 :
384 0 : if (ret != Z_STREAM_END && bytes_left != 0)
385 : ret = -EIO;
386 : else
387 : ret = 0;
388 :
389 0 : zlib_inflateEnd(&workspace->inf_strm);
390 0 : return ret;
391 : }
392 :
393 : struct btrfs_compress_op btrfs_zlib_compress = {
394 : .alloc_workspace = zlib_alloc_workspace,
395 : .free_workspace = zlib_free_workspace,
396 : .compress_pages = zlib_compress_pages,
397 : .decompress_biovec = zlib_decompress_biovec,
398 : .decompress = zlib_decompress,
399 : };
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