[linux.git] / fs / btrfs / lzo.c

/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/bio.h>
#include <linux/lzo.h>
#include "compression.h"

#define LZO_LEN	4

struct workspace {
	void *mem;
	void *buf;	/* where compressed data goes */
	void *cbuf;	/* where decompressed data goes */
	struct list_head list;
};

static void lzo_free_workspace(struct list_head *ws)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);

	vfree(workspace->buf);
	vfree(workspace->cbuf);
	vfree(workspace->mem);
	kfree(workspace);
}

static struct list_head *lzo_alloc_workspace(void)
{
	struct workspace *workspace;

	workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
	if (!workspace)
		return ERR_PTR(-ENOMEM);

	workspace->mem = vmalloc(LZO1X_MEM_COMPRESS);
	workspace->buf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
	workspace->cbuf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
	if (!workspace->mem || !workspace->buf || !workspace->cbuf)
		goto fail;

	INIT_LIST_HEAD(&workspace->list);

	return &workspace->list;
fail:
	lzo_free_workspace(&workspace->list);
	return ERR_PTR(-ENOMEM);
}

static inline void write_compress_length(char *buf, size_t len)
{
	__le32 dlen;

	dlen = cpu_to_le32(len);
	memcpy(buf, &dlen, LZO_LEN);
}

static inline size_t read_compress_length(char *buf)
{
	__le32 dlen;

	memcpy(&dlen, buf, LZO_LEN);
	return le32_to_cpu(dlen);
}

static int lzo_compress_pages(struct list_head *ws,
			      struct address_space *mapping,
			      u64 start, unsigned long len,
			      struct page **pages,
			      unsigned long nr_dest_pages,
			      unsigned long *out_pages,
			      unsigned long *total_in,
			      unsigned long *total_out,
			      unsigned long max_out)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	int ret = 0;
	char *data_in;
	char *cpage_out;
	int nr_pages = 0;
	struct page *in_page = NULL;
	struct page *out_page = NULL;
	unsigned long bytes_left;

	size_t in_len;
	size_t out_len;
	char *buf;
	unsigned long tot_in = 0;
	unsigned long tot_out = 0;
	unsigned long pg_bytes_left;
	unsigned long out_offset;
	unsigned long bytes;

	*out_pages = 0;
	*total_out = 0;
	*total_in = 0;

	in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
	data_in = kmap(in_page);

	/*
	 * store the size of all chunks of compressed data in
	 * the first 4 bytes
	 */
	out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (out_page == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	cpage_out = kmap(out_page);
	out_offset = LZO_LEN;
	tot_out = LZO_LEN;
	pages[0] = out_page;
	nr_pages = 1;
	pg_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;

	/* compress at most one page of data each time */
	in_len = min(len, PAGE_CACHE_SIZE);
	while (tot_in < len) {
		ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
				       &out_len, workspace->mem);
		if (ret != LZO_E_OK) {
			printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
			       ret);
			ret = -1;
			goto out;
		}

		/* store the size of this chunk of compressed data */
		write_compress_length(cpage_out + out_offset, out_len);
		tot_out += LZO_LEN;
		out_offset += LZO_LEN;
		pg_bytes_left -= LZO_LEN;

		tot_in += in_len;
		tot_out += out_len;

		/* copy bytes from the working buffer into the pages */
		buf = workspace->cbuf;
		while (out_len) {
			bytes = min_t(unsigned long, pg_bytes_left, out_len);

			memcpy(cpage_out + out_offset, buf, bytes);

			out_len -= bytes;
			pg_bytes_left -= bytes;
			buf += bytes;
			out_offset += bytes;

			/*
			 * we need another page for writing out.
			 *
			 * Note if there's less than 4 bytes left, we just
			 * skip to a new page.
			 */
			if ((out_len == 0 && pg_bytes_left < LZO_LEN) ||
			    pg_bytes_left == 0) {
				if (pg_bytes_left) {
					memset(cpage_out + out_offset, 0,
					       pg_bytes_left);
					tot_out += pg_bytes_left;
				}

				/* we're done, don't allocate new page */
				if (out_len == 0 && tot_in >= len)
					break;

				kunmap(out_page);
				if (nr_pages == nr_dest_pages) {
					out_page = NULL;
					ret = -1;
					goto out;
				}

				out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
				if (out_page == NULL) {
					ret = -ENOMEM;
					goto out;
				}
				cpage_out = kmap(out_page);
				pages[nr_pages++] = out_page;

				pg_bytes_left = PAGE_CACHE_SIZE;
				out_offset = 0;
			}
		}

		/* we're making it bigger, give up */
		if (tot_in > 8192 && tot_in < tot_out)
			goto out;

		/* we're all done */
		if (tot_in >= len)
			break;

		if (tot_out > max_out)
			break;

		bytes_left = len - tot_in;
		kunmap(in_page);
		page_cache_release(in_page);

		start += PAGE_CACHE_SIZE;
		in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
		data_in = kmap(in_page);
		in_len = min(bytes_left, PAGE_CACHE_SIZE);
	}

	if (tot_out > tot_in)
		goto out;

	/* store the size of all chunks of compressed data */
	cpage_out = kmap(pages[0]);
	write_compress_length(cpage_out, tot_out);

	kunmap(pages[0]);

	ret = 0;
	*total_out = tot_out;
	*total_in = tot_in;
out:
	*out_pages = nr_pages;
	if (out_page)
		kunmap(out_page);

	if (in_page) {
		kunmap(in_page);
		page_cache_release(in_page);
	}

	return ret;
}

static int lzo_decompress_biovec(struct list_head *ws,
				 struct page **pages_in,
				 u64 disk_start,
				 struct bio_vec *bvec,
				 int vcnt,
				 size_t srclen)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	int ret = 0, ret2;
	char *data_in;
	unsigned long page_in_index = 0;
	unsigned long page_out_index = 0;
	unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
					PAGE_CACHE_SIZE;
	unsigned long buf_start;
	unsigned long buf_offset = 0;
	unsigned long bytes;
	unsigned long working_bytes;
	unsigned long pg_offset;

	size_t in_len;
	size_t out_len;
	unsigned long in_offset;
	unsigned long in_page_bytes_left;
	unsigned long tot_in;
	unsigned long tot_out;
	unsigned long tot_len;
	char *buf;
	bool may_late_unmap, need_unmap;

	data_in = kmap(pages_in[0]);
	tot_len = read_compress_length(data_in);

	tot_in = LZO_LEN;
	in_offset = LZO_LEN;
	tot_len = min_t(size_t, srclen, tot_len);
	in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;

	tot_out = 0;
	pg_offset = 0;

	while (tot_in < tot_len) {
		in_len = read_compress_length(data_in + in_offset);
		in_page_bytes_left -= LZO_LEN;
		in_offset += LZO_LEN;
		tot_in += LZO_LEN;

		tot_in += in_len;
		working_bytes = in_len;
		may_late_unmap = need_unmap = false;

		/* fast path: avoid using the working buffer */
		if (in_page_bytes_left >= in_len) {
			buf = data_in + in_offset;
			bytes = in_len;
			may_late_unmap = true;
			goto cont;
		}

		/* copy bytes from the pages into the working buffer */
		buf = workspace->cbuf;
		buf_offset = 0;
		while (working_bytes) {
			bytes = min(working_bytes, in_page_bytes_left);

			memcpy(buf + buf_offset, data_in + in_offset, bytes);
			buf_offset += bytes;
cont:
			working_bytes -= bytes;
			in_page_bytes_left -= bytes;
			in_offset += bytes;

			/* check if we need to pick another page */
			if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
			    || in_page_bytes_left == 0) {
				tot_in += in_page_bytes_left;

				if (working_bytes == 0 && tot_in >= tot_len)
					break;

				if (page_in_index + 1 >= total_pages_in) {
					ret = -1;
					goto done;
				}

				if (may_late_unmap)
					need_unmap = true;
				else
					kunmap(pages_in[page_in_index]);

				data_in = kmap(pages_in[++page_in_index]);

				in_page_bytes_left = PAGE_CACHE_SIZE;
				in_offset = 0;
			}
		}

		out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
		ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
					    &out_len);
		if (need_unmap)
			kunmap(pages_in[page_in_index - 1]);
		if (ret != LZO_E_OK) {
			printk(KERN_WARNING "btrfs decompress failed\n");
			ret = -1;
			break;
		}

		buf_start = tot_out;
		tot_out += out_len;

		ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
						 tot_out, disk_start,
						 bvec, vcnt,
						 &page_out_index, &pg_offset);
		if (ret2 == 0)
			break;
	}
done:
	kunmap(pages_in[page_in_index]);
	return ret;
}

static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
			  struct page *dest_page,
			  unsigned long start_byte,
			  size_t srclen, size_t destlen)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	size_t in_len;
	size_t out_len;
	size_t tot_len;
	int ret = 0;
	char *kaddr;
	unsigned long bytes;

	BUG_ON(srclen < LZO_LEN);

	tot_len = read_compress_length(data_in);
	data_in += LZO_LEN;

	in_len = read_compress_length(data_in);
	data_in += LZO_LEN;

	out_len = PAGE_CACHE_SIZE;
	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
	if (ret != LZO_E_OK) {
		printk(KERN_WARNING "btrfs decompress failed!\n");
		ret = -1;
		goto out;
	}

	if (out_len < start_byte) {
		ret = -1;
		goto out;
	}

	bytes = min_t(unsigned long, destlen, out_len - start_byte);

	kaddr = kmap_atomic(dest_page);
	memcpy(kaddr, workspace->buf + start_byte, bytes);
	kunmap_atomic(kaddr);
out:
	return ret;
}

struct btrfs_compress_op btrfs_lzo_compress = {
	.alloc_workspace	= lzo_alloc_workspace,
	.free_workspace		= lzo_free_workspace,
	.compress_pages		= lzo_compress_pages,
	.decompress_biovec	= lzo_decompress_biovec,
	.decompress		= lzo_decompress,
};
Commit	Line	Data
a6fa6fae LZ	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
	19	#include <linux/kernel.h>
	20	#include <linux/slab.h>
	21	#include <linux/vmalloc.h>
	22	#include <linux/init.h>
	23	#include <linux/err.h>
	24	#include <linux/sched.h>
	25	#include <linux/pagemap.h>
	26	#include <linux/bio.h>
	27	#include <linux/lzo.h>
	28	#include "compression.h"
	29
	30	#define LZO_LEN 4
	31
	32	struct workspace {
	33	void *mem;
	34	void buf; / where compressed data goes */
	35	void cbuf; / where decompressed data goes */
	36	struct list_head list;
	37	};
	38
	39	static void lzo_free_workspace(struct list_head *ws)
	40	{
	41	struct workspace *workspace = list_entry(ws, struct workspace, list);
	42
	43	vfree(workspace->buf);
	44	vfree(workspace->cbuf);
	45	vfree(workspace->mem);
	46	kfree(workspace);
	47	}
	48
	49	static struct list_head *lzo_alloc_workspace(void)
	50	{
	51	struct workspace *workspace;
	52
	53	workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
	54	if (!workspace)
	55	return ERR_PTR(-ENOMEM);
	56
	57	workspace->mem = vmalloc(LZO1X_MEM_COMPRESS);
	58	workspace->buf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
	59	workspace->cbuf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
	60	if (!workspace->mem \|\| !workspace->buf \|\| !workspace->cbuf)
	61	goto fail;
	62
	63	INIT_LIST_HEAD(&workspace->list);
	64
65	return &workspace->list;
66	fail:
67	lzo_free_workspace(&workspace->list);
68	return ERR_PTR(-ENOMEM);
69	}
70
71	static inline void write_compress_length(char *buf, size_t len)
72	{
73	__le32 dlen;
74
75	dlen = cpu_to_le32(len);
76	memcpy(buf, &dlen, LZO_LEN);
77	}
78
79	static inline size_t read_compress_length(char *buf)
80	{
81	__le32 dlen;
82
83	memcpy(&dlen, buf, LZO_LEN);
84	return le32_to_cpu(dlen);
85	}
86
87	static int lzo_compress_pages(struct list_head *ws,
88	struct address_space *mapping,
89	u64 start, unsigned long len,
90	struct page **pages,
91	unsigned long nr_dest_pages,
92	unsigned long *out_pages,
93	unsigned long *total_in,
94	unsigned long *total_out,
95	unsigned long max_out)
96	{
97	struct workspace *workspace = list_entry(ws, struct workspace, list);
98	int ret = 0;
99	char *data_in;
100	char *cpage_out;
101	int nr_pages = 0;
102	struct page *in_page = NULL;
103	struct page *out_page = NULL;
104	unsigned long bytes_left;
105
106	size_t in_len;
107	size_t out_len;
108	char *buf;
109	unsigned long tot_in = 0;
110	unsigned long tot_out = 0;
111	unsigned long pg_bytes_left;
112	unsigned long out_offset;
113	unsigned long bytes;
114
115	*out_pages = 0;
116	*total_out = 0;
117	*total_in = 0;
118
119	in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
120	data_in = kmap(in_page);
121
122	/*
123	* store the size of all chunks of compressed data in
124	* the first 4 bytes
125	*/
126	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
127	if (out_page == NULL) {
128	ret = -ENOMEM;
129	goto out;
130	}
131	cpage_out = kmap(out_page);
132	out_offset = LZO_LEN;
133	tot_out = LZO_LEN;
134	pages[0] = out_page;
135	nr_pages = 1;
136	pg_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
137
138	/* compress at most one page of data each time */
139	in_len = min(len, PAGE_CACHE_SIZE);
140	while (tot_in < len) {
141	ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
142	&out_len, workspace->mem);
143	if (ret != LZO_E_OK) {
144	printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
145	ret);
146	ret = -1;
147	goto out;
148	}
149
150	/* store the size of this chunk of compressed data */
151	write_compress_length(cpage_out + out_offset, out_len);
152	tot_out += LZO_LEN;
153	out_offset += LZO_LEN;
154	pg_bytes_left -= LZO_LEN;
155
156	tot_in += in_len;
157	tot_out += out_len;
158
159	/* copy bytes from the working buffer into the pages */
160	buf = workspace->cbuf;
161	while (out_len) {
162	bytes = min_t(unsigned long, pg_bytes_left, out_len);
163
164	memcpy(cpage_out + out_offset, buf, bytes);
165
166	out_len -= bytes;
167	pg_bytes_left -= bytes;
168	buf += bytes;
169	out_offset += bytes;
170
171	/*
172	* we need another page for writing out.
173	*
174	* Note if there's less than 4 bytes left, we just
175	* skip to a new page.
176	*/
177	if ((out_len == 0 && pg_bytes_left < LZO_LEN) \|\|
178	pg_bytes_left == 0) {
179	if (pg_bytes_left) {
180	memset(cpage_out + out_offset, 0,
181	pg_bytes_left);
182	tot_out += pg_bytes_left;
183	}
184
185	/* we're done, don't allocate new page */
186	if (out_len == 0 && tot_in >= len)
187	break;
188
189	kunmap(out_page);
190	if (nr_pages == nr_dest_pages) {
191	out_page = NULL;
192	ret = -1;
193	goto out;
194	}
195
196	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
197	if (out_page == NULL) {
198	ret = -ENOMEM;
199	goto out;
200	}
201	cpage_out = kmap(out_page);
202	pages[nr_pages++] = out_page;
203
204	pg_bytes_left = PAGE_CACHE_SIZE;
205	out_offset = 0;
206	}
207	}
208
209	/* we're making it bigger, give up */
210	if (tot_in > 8192 && tot_in < tot_out)
211	goto out;
212
213	/* we're all done */
214	if (tot_in >= len)
215	break;
216
217	if (tot_out > max_out)
218	break;
219
220	bytes_left = len - tot_in;
221	kunmap(in_page);
222	page_cache_release(in_page);
223
224	start += PAGE_CACHE_SIZE;
225	in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
226	data_in = kmap(in_page);
227	in_len = min(bytes_left, PAGE_CACHE_SIZE);
228	}
229
230	if (tot_out > tot_in)
231	goto out;
232
233	/* store the size of all chunks of compressed data */
234	cpage_out = kmap(pages[0]);
235	write_compress_length(cpage_out, tot_out);
236
237	kunmap(pages[0]);
238
239	ret = 0;
240	*total_out = tot_out;
241	*total_in = tot_in;
242	out:
243	*out_pages = nr_pages;
244	if (out_page)
245	kunmap(out_page);
246
247	if (in_page) {
248	kunmap(in_page);
249	page_cache_release(in_page);
250	}
251
252	return ret;
253	}
254
255	static int lzo_decompress_biovec(struct list_head *ws,
256	struct page **pages_in,
257	u64 disk_start,
258	struct bio_vec *bvec,
259	int vcnt,
260	size_t srclen)
261	{
262	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	263	int ret = 0, ret2;
a6fa6fae	264	char *data_in;
a6fa6fae LZ	265	unsigned long page_in_index = 0;
a6fa6fae LZ	266	unsigned long page_out_index = 0;
a6fa6fae LZ	267	unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
	268	PAGE_CACHE_SIZE;
	269	unsigned long buf_start;
	270	unsigned long buf_offset = 0;
	271	unsigned long bytes;
	272	unsigned long working_bytes;
	273	unsigned long pg_offset;
a6fa6fae LZ	274
	275	size_t in_len;
	276	size_t out_len;
	277	unsigned long in_offset;
	278	unsigned long in_page_bytes_left;
	279	unsigned long tot_in;
	280	unsigned long tot_out;
	281	unsigned long tot_len;
	282	char *buf;
ca9b688c	283	bool may_late_unmap, need_unmap;
a6fa6fae LZ	284
	285	data_in = kmap(pages_in[0]);
	286	tot_len = read_compress_length(data_in);
	287
	288	tot_in = LZO_LEN;
	289	in_offset = LZO_LEN;
	290	tot_len = min_t(size_t, srclen, tot_len);
	291	in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
	292
	293	tot_out = 0;
a6fa6fae LZ	294	pg_offset = 0;
	295
	296	while (tot_in < tot_len) {
	297	in_len = read_compress_length(data_in + in_offset);
	298	in_page_bytes_left -= LZO_LEN;
	299	in_offset += LZO_LEN;
	300	tot_in += LZO_LEN;
	301
	302	tot_in += in_len;
	303	working_bytes = in_len;
ca9b688c	304	may_late_unmap = need_unmap = false;
a6fa6fae LZ	305
	306	/* fast path: avoid using the working buffer */
	307	if (in_page_bytes_left >= in_len) {
	308	buf = data_in + in_offset;
	309	bytes = in_len;
ca9b688c	310	may_late_unmap = true;
a6fa6fae LZ	311	goto cont;
	312	}
	313
	314	/* copy bytes from the pages into the working buffer */
	315	buf = workspace->cbuf;
	316	buf_offset = 0;
	317	while (working_bytes) {
	318	bytes = min(working_bytes, in_page_bytes_left);
	319
	320	memcpy(buf + buf_offset, data_in + in_offset, bytes);
	321	buf_offset += bytes;
	322	cont:
	323	working_bytes -= bytes;
	324	in_page_bytes_left -= bytes;
	325	in_offset += bytes;
	326
	327	/* check if we need to pick another page */
	328	if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
	329	\|\| in_page_bytes_left == 0) {
	330	tot_in += in_page_bytes_left;
	331
	332	if (working_bytes == 0 && tot_in >= tot_len)
	333	break;
	334
ca9b688c	335	if (page_in_index + 1 >= total_pages_in) {
a6fa6fae	336	ret = -1;
a6fa6fae LZ	337	goto done;
a6fa6fae LZ	338	}
ca9b688c LZ	339
	340	if (may_late_unmap)
	341	need_unmap = true;
	342	else
	343	kunmap(pages_in[page_in_index]);
	344
	345	data_in = kmap(pages_in[++page_in_index]);
a6fa6fae LZ	346
	347	in_page_bytes_left = PAGE_CACHE_SIZE;
	348	in_offset = 0;
	349	}
	350	}
	351
	352	out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
	353	ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
	354	&out_len);
ca9b688c LZ	355	if (need_unmap)
ca9b688c LZ	356	kunmap(pages_in[page_in_index - 1]);
a6fa6fae LZ	357	if (ret != LZO_E_OK) {
	358	printk(KERN_WARNING "btrfs decompress failed\n");
	359	ret = -1;
	360	break;
	361	}
	362
a6fa6fae	363	buf_start = tot_out;
a6fa6fae LZ	364	tot_out += out_len;
a6fa6fae LZ	365
3a39c18d LZ	366	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
	367	tot_out, disk_start,
	368	bvec, vcnt,
	369	&page_out_index, &pg_offset);
	370	if (ret2 == 0)
a6fa6fae	371	break;
a6fa6fae LZ	372	}
a6fa6fae LZ	373	done:
ca9b688c	374	kunmap(pages_in[page_in_index]);
a6fa6fae LZ	375	return ret;
	376	}
	377
	378	static int lzo_decompress(struct list_head ws, unsigned char data_in,
	379	struct page *dest_page,
	380	unsigned long start_byte,
	381	size_t srclen, size_t destlen)
	382	{
	383	struct workspace *workspace = list_entry(ws, struct workspace, list);
	384	size_t in_len;
	385	size_t out_len;
	386	size_t tot_len;
	387	int ret = 0;
	388	char *kaddr;
	389	unsigned long bytes;
	390
	391	BUG_ON(srclen < LZO_LEN);
	392
	393	tot_len = read_compress_length(data_in);
	394	data_in += LZO_LEN;
	395
	396	in_len = read_compress_length(data_in);
	397	data_in += LZO_LEN;
	398
	399	out_len = PAGE_CACHE_SIZE;
	400	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
	401	if (ret != LZO_E_OK) {
	402	printk(KERN_WARNING "btrfs decompress failed!\n");
	403	ret = -1;
	404	goto out;
	405	}
	406
	407	if (out_len < start_byte) {
	408	ret = -1;
	409	goto out;
	410	}
	411
	412	bytes = min_t(unsigned long, destlen, out_len - start_byte);
	413
7ac687d9	414	kaddr = kmap_atomic(dest_page);
a6fa6fae	415	memcpy(kaddr, workspace->buf + start_byte, bytes);
7ac687d9	416	kunmap_atomic(kaddr);
a6fa6fae LZ	417	out:
	418	return ret;
	419	}
	420
	421	struct btrfs_compress_op btrfs_lzo_compress = {
	422	.alloc_workspace = lzo_alloc_workspace,
	423	.free_workspace = lzo_free_workspace,
	424	.compress_pages = lzo_compress_pages,
	425	.decompress_biovec = lzo_decompress_biovec,
	426	.decompress = lzo_decompress,
	427	};