[mirror_ubuntu-bionic-kernel.git] / fs / btrfs / zlib.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.
 *
 * Based on jffs2 zlib code:
 * Copyright © 2001-2007 Red Hat, Inc.
 * Created by David Woodhouse <dwmw2@infradead.org>
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/zlib.h>
#include <linux/zutil.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 "compression.h"

struct workspace {
	z_stream inf_strm;
	z_stream def_strm;
	char *buf;
	struct list_head list;
};

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

	vfree(workspace->def_strm.workspace);
	vfree(workspace->inf_strm.workspace);
	kfree(workspace->buf);
	kfree(workspace);
}

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

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

	workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
	workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
	workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
	if (!workspace->def_strm.workspace ||
	    !workspace->inf_strm.workspace || !workspace->buf)
		goto fail;

	INIT_LIST_HEAD(&workspace->list);

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

static int zlib_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;
	char *data_in;
	char *cpage_out;
	int nr_pages = 0;
	struct page *in_page = NULL;
	struct page *out_page = NULL;
	unsigned long bytes_left;

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

	if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
		printk(KERN_WARNING "deflateInit failed\n");
		ret = -1;
		goto out;
	}

	workspace->def_strm.total_in = 0;
	workspace->def_strm.total_out = 0;

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

	out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (out_page == NULL) {
		ret = -1;
		goto out;
	}
	cpage_out = kmap(out_page);
	pages[0] = out_page;
	nr_pages = 1;

	workspace->def_strm.next_in = data_in;
	workspace->def_strm.next_out = cpage_out;
	workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
	workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);

	while (workspace->def_strm.total_in < len) {
		ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
		if (ret != Z_OK) {
			printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
			       ret);
			zlib_deflateEnd(&workspace->def_strm);
			ret = -1;
			goto out;
		}

		/* we're making it bigger, give up */
		if (workspace->def_strm.total_in > 8192 &&
		    workspace->def_strm.total_in <
		    workspace->def_strm.total_out) {
			ret = -1;
			goto out;
		}
		/* we need another page for writing out.  Test this
		 * before the total_in so we will pull in a new page for
		 * the stream end if required
		 */
		if (workspace->def_strm.avail_out == 0) {
			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 = -1;
				goto out;
			}
			cpage_out = kmap(out_page);
			pages[nr_pages] = out_page;
			nr_pages++;
			workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
			workspace->def_strm.next_out = cpage_out;
		}
		/* we're all done */
		if (workspace->def_strm.total_in >= len)
			break;

		/* we've read in a full page, get a new one */
		if (workspace->def_strm.avail_in == 0) {
			if (workspace->def_strm.total_out > max_out)
				break;

			bytes_left = len - workspace->def_strm.total_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);
			workspace->def_strm.avail_in = min(bytes_left,
							   PAGE_CACHE_SIZE);
			workspace->def_strm.next_in = data_in;
		}
	}
	workspace->def_strm.avail_in = 0;
	ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
	zlib_deflateEnd(&workspace->def_strm);

	if (ret != Z_STREAM_END) {
		ret = -1;
		goto out;
	}

	if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
		ret = -1;
		goto out;
	}

	ret = 0;
	*total_out = workspace->def_strm.total_out;
	*total_in = workspace->def_strm.total_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 zlib_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;
	int wbits = MAX_WBITS;
	char *data_in;
	size_t total_out = 0;
	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 pg_offset;

	data_in = kmap(pages_in[page_in_index]);
	workspace->inf_strm.next_in = data_in;
	workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
	workspace->inf_strm.total_in = 0;

	workspace->inf_strm.total_out = 0;
	workspace->inf_strm.next_out = workspace->buf;
	workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
	pg_offset = 0;

	/* If it's deflate, and it's got no preset dictionary, then
	   we can tell zlib to skip the adler32 check. */
	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	    ((data_in[0] & 0x0f) == Z_DEFLATED) &&
	    !(((data_in[0]<<8) + data_in[1]) % 31)) {

		wbits = -((data_in[0] >> 4) + 8);
		workspace->inf_strm.next_in += 2;
		workspace->inf_strm.avail_in -= 2;
	}

	if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
		printk(KERN_WARNING "inflateInit failed\n");
		return -1;
	}
	while (workspace->inf_strm.total_in < srclen) {
		ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
		if (ret != Z_OK && ret != Z_STREAM_END)
			break;

		buf_start = total_out;
		total_out = workspace->inf_strm.total_out;

		/* we didn't make progress in this inflate call, we're done */
		if (buf_start == total_out)
			break;

		ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
						 total_out, disk_start,
						 bvec, vcnt,
						 &page_out_index, &pg_offset);
		if (ret2 == 0) {
			ret = 0;
			goto done;
		}

		workspace->inf_strm.next_out = workspace->buf;
		workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;

		if (workspace->inf_strm.avail_in == 0) {
			unsigned long tmp;
			kunmap(pages_in[page_in_index]);
			page_in_index++;
			if (page_in_index >= total_pages_in) {
				data_in = NULL;
				break;
			}
			data_in = kmap(pages_in[page_in_index]);
			workspace->inf_strm.next_in = data_in;
			tmp = srclen - workspace->inf_strm.total_in;
			workspace->inf_strm.avail_in = min(tmp,
							   PAGE_CACHE_SIZE);
		}
	}
	if (ret != Z_STREAM_END)
		ret = -1;
	else
		ret = 0;
done:
	zlib_inflateEnd(&workspace->inf_strm);
	if (data_in)
		kunmap(pages_in[page_in_index]);
	return ret;
}

static int zlib_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);
	int ret = 0;
	int wbits = MAX_WBITS;
	unsigned long bytes_left = destlen;
	unsigned long total_out = 0;
	char *kaddr;

	workspace->inf_strm.next_in = data_in;
	workspace->inf_strm.avail_in = srclen;
	workspace->inf_strm.total_in = 0;

	workspace->inf_strm.next_out = workspace->buf;
	workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
	workspace->inf_strm.total_out = 0;
	/* If it's deflate, and it's got no preset dictionary, then
	   we can tell zlib to skip the adler32 check. */
	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	    ((data_in[0] & 0x0f) == Z_DEFLATED) &&
	    !(((data_in[0]<<8) + data_in[1]) % 31)) {

		wbits = -((data_in[0] >> 4) + 8);
		workspace->inf_strm.next_in += 2;
		workspace->inf_strm.avail_in -= 2;
	}

	if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
		printk(KERN_WARNING "inflateInit failed\n");
		return -1;
	}

	while (bytes_left > 0) {
		unsigned long buf_start;
		unsigned long buf_offset;
		unsigned long bytes;
		unsigned long pg_offset = 0;

		ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
		if (ret != Z_OK && ret != Z_STREAM_END)
			break;

		buf_start = total_out;
		total_out = workspace->inf_strm.total_out;

		if (total_out == buf_start) {
			ret = -1;
			break;
		}

		if (total_out <= start_byte)
			goto next;

		if (total_out > start_byte && buf_start < start_byte)
			buf_offset = start_byte - buf_start;
		else
			buf_offset = 0;

		bytes = min(PAGE_CACHE_SIZE - pg_offset,
			    PAGE_CACHE_SIZE - buf_offset);
		bytes = min(bytes, bytes_left);

		kaddr = kmap_atomic(dest_page, KM_USER0);
		memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
		kunmap_atomic(kaddr, KM_USER0);

		pg_offset += bytes;
		bytes_left -= bytes;
next:
		workspace->inf_strm.next_out = workspace->buf;
		workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
	}

	if (ret != Z_STREAM_END && bytes_left != 0)
		ret = -1;
	else
		ret = 0;

	zlib_inflateEnd(&workspace->inf_strm);
	return ret;
}

struct btrfs_compress_op btrfs_zlib_compress = {
	.alloc_workspace	= zlib_alloc_workspace,
	.free_workspace		= zlib_free_workspace,
	.compress_pages		= zlib_compress_pages,
	.decompress_biovec	= zlib_decompress_biovec,
	.decompress		= zlib_decompress,
};
Commit	Line	Data
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	34
c8b97818 CM	35	struct workspace {
	36	z_stream inf_strm;
	37	z_stream def_strm;
	38	char *buf;
	39	struct list_head list;
	40	};
	41
261507a0 LZ	42	static void zlib_free_workspace(struct list_head *ws)
	43	{
	44	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	45
261507a0 LZ	46	vfree(workspace->def_strm.workspace);
	47	vfree(workspace->inf_strm.workspace);
	48	kfree(workspace->buf);
	49	kfree(workspace);
	50	}
	51
	52	static struct list_head *zlib_alloc_workspace(void)
c8b97818 CM	53	{
c8b97818 CM	54	struct workspace *workspace;
8844355d	55
c8b97818	56	workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
261507a0 LZ	57	if (!workspace)
261507a0 LZ	58	return ERR_PTR(-ENOMEM);
c8b97818 CM	59
c8b97818 CM	60	workspace->def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
c8b97818	61	workspace->inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
c8b97818	62	workspace->buf = kmalloc(PAGE_CACHE_SIZE, GFP_NOFS);
261507a0 LZ	63	if (!workspace->def_strm.workspace \|\|
	64	!workspace->inf_strm.workspace \|\| !workspace->buf)
	65	goto fail;
c8b97818	66
261507a0	67	INIT_LIST_HEAD(&workspace->list);
c8b97818	68
261507a0 LZ	69	return &workspace->list;
	70	fail:
	71	zlib_free_workspace(&workspace->list);
	72	return ERR_PTR(-ENOMEM);
c8b97818 CM	73	}
c8b97818 CM	74
261507a0 LZ	75	static int zlib_compress_pages(struct list_head *ws,
	76	struct address_space *mapping,
	77	u64 start, unsigned long len,
	78	struct page **pages,
	79	unsigned long nr_dest_pages,
	80	unsigned long *out_pages,
	81	unsigned long *total_in,
	82	unsigned long *total_out,
	83	unsigned long max_out)
c8b97818	84	{
261507a0	85	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	86	int ret;
c8b97818 CM	87	char *data_in;
	88	char *cpage_out;
	89	int nr_pages = 0;
	90	struct page *in_page = NULL;
	91	struct page *out_page = NULL;
c8b97818 CM	92	unsigned long bytes_left;
	93
	94	*out_pages = 0;
	95	*total_out = 0;
	96	*total_in = 0;
	97
c8b97818 CM	98	if (Z_OK != zlib_deflateInit(&workspace->def_strm, 3)) {
	99	printk(KERN_WARNING "deflateInit failed\n");
	100	ret = -1;
	101	goto out;
	102	}
	103
	104	workspace->def_strm.total_in = 0;
	105	workspace->def_strm.total_out = 0;
	106
	107	in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
	108	data_in = kmap(in_page);
	109
	110	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d LZ	111	if (out_page == NULL) {
	112	ret = -1;
	113	goto out;
	114	}
c8b97818 CM	115	cpage_out = kmap(out_page);
	116	pages[0] = out_page;
	117	nr_pages = 1;
	118
	119	workspace->def_strm.next_in = data_in;
	120	workspace->def_strm.next_out = cpage_out;
	121	workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
	122	workspace->def_strm.avail_in = min(len, PAGE_CACHE_SIZE);
	123
c8b97818 CM	124	while (workspace->def_strm.total_in < len) {
	125	ret = zlib_deflate(&workspace->def_strm, Z_SYNC_FLUSH);
	126	if (ret != Z_OK) {
	127	printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
	128	ret);
	129	zlib_deflateEnd(&workspace->def_strm);
	130	ret = -1;
	131	goto out;
	132	}
	133
	134	/* we're making it bigger, give up */
	135	if (workspace->def_strm.total_in > 8192 &&
	136	workspace->def_strm.total_in <
	137	workspace->def_strm.total_out) {
	138	ret = -1;
	139	goto out;
	140	}
	141	/* we need another page for writing out. Test this
	142	* before the total_in so we will pull in a new page for
	143	* the stream end if required
	144	*/
	145	if (workspace->def_strm.avail_out == 0) {
	146	kunmap(out_page);
	147	if (nr_pages == nr_dest_pages) {
	148	out_page = NULL;
	149	ret = -1;
	150	goto out;
	151	}
	152	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d LZ	153	if (out_page == NULL) {
	154	ret = -1;
	155	goto out;
	156	}
c8b97818 CM	157	cpage_out = kmap(out_page);
	158	pages[nr_pages] = out_page;
	159	nr_pages++;
	160	workspace->def_strm.avail_out = PAGE_CACHE_SIZE;
	161	workspace->def_strm.next_out = cpage_out;
	162	}
	163	/* we're all done */
	164	if (workspace->def_strm.total_in >= len)
	165	break;
	166
	167	/* we've read in a full page, get a new one */
	168	if (workspace->def_strm.avail_in == 0) {
	169	if (workspace->def_strm.total_out > max_out)
	170	break;
	171
	172	bytes_left = len - workspace->def_strm.total_in;
	173	kunmap(in_page);
	174	page_cache_release(in_page);
	175
	176	start += PAGE_CACHE_SIZE;
	177	in_page = find_get_page(mapping,
	178	start >> PAGE_CACHE_SHIFT);
	179	data_in = kmap(in_page);
	180	workspace->def_strm.avail_in = min(bytes_left,
	181	PAGE_CACHE_SIZE);
	182	workspace->def_strm.next_in = data_in;
	183	}
	184	}
	185	workspace->def_strm.avail_in = 0;
	186	ret = zlib_deflate(&workspace->def_strm, Z_FINISH);
	187	zlib_deflateEnd(&workspace->def_strm);
	188
	189	if (ret != Z_STREAM_END) {
	190	ret = -1;
	191	goto out;
	192	}
	193
	194	if (workspace->def_strm.total_out >= workspace->def_strm.total_in) {
	195	ret = -1;
	196	goto out;
	197	}
	198
	199	ret = 0;
	200	*total_out = workspace->def_strm.total_out;
	201	*total_in = workspace->def_strm.total_in;
	202	out:
	203	*out_pages = nr_pages;
	204	if (out_page)
	205	kunmap(out_page);
	206
	207	if (in_page) {
	208	kunmap(in_page);
	209	page_cache_release(in_page);
	210	}
c8b97818 CM	211	return ret;
	212	}
	213
261507a0 LZ	214	static int zlib_decompress_biovec(struct list_head ws, struct page *pages_in,
	215	u64 disk_start,
	216	struct bio_vec *bvec,
	217	int vcnt,
	218	size_t srclen)
c8b97818	219	{
261507a0	220	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	221	int ret = 0, ret2;
c8b97818	222	int wbits = MAX_WBITS;
c8b97818 CM	223	char *data_in;
c8b97818 CM	224	size_t total_out = 0;
c8b97818 CM	225	unsigned long page_in_index = 0;
c8b97818 CM	226	unsigned long page_out_index = 0;
c8b97818 CM	227	unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
	228	PAGE_CACHE_SIZE;
	229	unsigned long buf_start;
c8b97818	230	unsigned long pg_offset;
c8b97818	231
c8b97818 CM	232	data_in = kmap(pages_in[page_in_index]);
c8b97818 CM	233	workspace->inf_strm.next_in = data_in;
5b050f04	234	workspace->inf_strm.avail_in = min_t(size_t, srclen, PAGE_CACHE_SIZE);
c8b97818 CM	235	workspace->inf_strm.total_in = 0;
	236
	237	workspace->inf_strm.total_out = 0;
	238	workspace->inf_strm.next_out = workspace->buf;
	239	workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
c8b97818 CM	240	pg_offset = 0;
	241
	242	/* If it's deflate, and it's got no preset dictionary, then
	243	we can tell zlib to skip the adler32 check. */
	244	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	245	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	246	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	247
	248	wbits = -((data_in[0] >> 4) + 8);
	249	workspace->inf_strm.next_in += 2;
	250	workspace->inf_strm.avail_in -= 2;
	251	}
	252
	253	if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
	254	printk(KERN_WARNING "inflateInit failed\n");
261507a0	255	return -1;
c8b97818	256	}
d397712b	257	while (workspace->inf_strm.total_in < srclen) {
c8b97818	258	ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
d397712b	259	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	260	break;
c8b97818	261
3a39c18d	262	buf_start = total_out;
c8b97818 CM	263	total_out = workspace->inf_strm.total_out;
c8b97818 CM	264
3a39c18d LZ	265	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	266	if (buf_start == total_out)
c8b97818	267	break;
c8b97818	268
3a39c18d LZ	269	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
	270	total_out, disk_start,
	271	bvec, vcnt,
	272	&page_out_index, &pg_offset);
	273	if (ret2 == 0) {
	274	ret = 0;
	275	goto done;
c8b97818	276	}
3a39c18d	277
c8b97818 CM	278	workspace->inf_strm.next_out = workspace->buf;
	279	workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
	280
	281	if (workspace->inf_strm.avail_in == 0) {
	282	unsigned long tmp;
	283	kunmap(pages_in[page_in_index]);
	284	page_in_index++;
	285	if (page_in_index >= total_pages_in) {
	286	data_in = NULL;
	287	break;
	288	}
	289	data_in = kmap(pages_in[page_in_index]);
	290	workspace->inf_strm.next_in = data_in;
	291	tmp = srclen - workspace->inf_strm.total_in;
	292	workspace->inf_strm.avail_in = min(tmp,
	293	PAGE_CACHE_SIZE);
	294	}
	295	}
d397712b	296	if (ret != Z_STREAM_END)
c8b97818	297	ret = -1;
d397712b	298	else
c8b97818	299	ret = 0;
c8b97818 CM	300	done:
	301	zlib_inflateEnd(&workspace->inf_strm);
	302	if (data_in)
	303	kunmap(pages_in[page_in_index]);
c8b97818 CM	304	return ret;
	305	}
	306
261507a0 LZ	307	static int zlib_decompress(struct list_head ws, unsigned char data_in,
	308	struct page *dest_page,
	309	unsigned long start_byte,
	310	size_t srclen, size_t destlen)
c8b97818	311	{
261507a0	312	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	313	int ret = 0;
c8b97818 CM	314	int wbits = MAX_WBITS;
c8b97818 CM	315	unsigned long bytes_left = destlen;
	316	unsigned long total_out = 0;
	317	char *kaddr;
	318
c8b97818 CM	319	workspace->inf_strm.next_in = data_in;
	320	workspace->inf_strm.avail_in = srclen;
	321	workspace->inf_strm.total_in = 0;
	322
	323	workspace->inf_strm.next_out = workspace->buf;
	324	workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
	325	workspace->inf_strm.total_out = 0;
	326	/* If it's deflate, and it's got no preset dictionary, then
	327	we can tell zlib to skip the adler32 check. */
	328	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	329	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	330	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	331
	332	wbits = -((data_in[0] >> 4) + 8);
	333	workspace->inf_strm.next_in += 2;
	334	workspace->inf_strm.avail_in -= 2;
	335	}
	336
	337	if (Z_OK != zlib_inflateInit2(&workspace->inf_strm, wbits)) {
	338	printk(KERN_WARNING "inflateInit failed\n");
261507a0	339	return -1;
c8b97818 CM	340	}
c8b97818 CM	341
d397712b	342	while (bytes_left > 0) {
c8b97818 CM	343	unsigned long buf_start;
	344	unsigned long buf_offset;
	345	unsigned long bytes;
	346	unsigned long pg_offset = 0;
	347
	348	ret = zlib_inflate(&workspace->inf_strm, Z_NO_FLUSH);
d397712b	349	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	350	break;
c8b97818 CM	351
	352	buf_start = total_out;
	353	total_out = workspace->inf_strm.total_out;
	354
	355	if (total_out == buf_start) {
	356	ret = -1;
	357	break;
	358	}
	359
d397712b	360	if (total_out <= start_byte)
c8b97818	361	goto next;
c8b97818	362
d397712b	363	if (total_out > start_byte && buf_start < start_byte)
c8b97818	364	buf_offset = start_byte - buf_start;
d397712b	365	else
c8b97818	366	buf_offset = 0;
c8b97818 CM	367
	368	bytes = min(PAGE_CACHE_SIZE - pg_offset,
	369	PAGE_CACHE_SIZE - buf_offset);
	370	bytes = min(bytes, bytes_left);
	371
	372	kaddr = kmap_atomic(dest_page, KM_USER0);
	373	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
	374	kunmap_atomic(kaddr, KM_USER0);
	375
	376	pg_offset += bytes;
	377	bytes_left -= bytes;
	378	next:
	379	workspace->inf_strm.next_out = workspace->buf;
	380	workspace->inf_strm.avail_out = PAGE_CACHE_SIZE;
	381	}
d397712b CM	382
d397712b CM	383	if (ret != Z_STREAM_END && bytes_left != 0)
c8b97818	384	ret = -1;
d397712b	385	else
c8b97818	386	ret = 0;
d397712b	387
c8b97818	388	zlib_inflateEnd(&workspace->inf_strm);
c8b97818 CM	389	return ret;
	390	}
	391
261507a0 LZ	392	struct btrfs_compress_op btrfs_zlib_compress = {
	393	.alloc_workspace = zlib_alloc_workspace,
	394	.free_workspace = zlib_free_workspace,
	395	.compress_pages = zlib_compress_pages,
	396	.decompress_biovec = zlib_decompress_biovec,
	397	.decompress = zlib_decompress,
	398	};