[linux-block.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 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->strm.workspace);
	kfree(workspace->buf);
	kfree(workspace);
}

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

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

	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
			zlib_inflate_workspacesize());
	workspace->strm.workspace = vmalloc(workspacesize);
	workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
	if (!workspace->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,
			       struct page **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;
	unsigned long len = *total_out;
	unsigned long nr_dest_pages = *out_pages;

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

	if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
		pr_warn("BTRFS: deflateInit failed\n");
		ret = -EIO;
		goto out;
	}

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

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

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

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

	while (workspace->strm.total_in < len) {
		ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
		if (ret != Z_OK) {
			pr_debug("BTRFS: deflate in loop returned %d\n",
			       ret);
			zlib_deflateEnd(&workspace->strm);
			ret = -EIO;
			goto out;
		}

		/* we're making it bigger, give up */
		if (workspace->strm.total_in > 8192 &&
		    workspace->strm.total_in <
		    workspace->strm.total_out) {
			ret = -E2BIG;
			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->strm.avail_out == 0) {
			kunmap(out_page);
			if (nr_pages == nr_dest_pages) {
				out_page = NULL;
				ret = -E2BIG;
				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;
			nr_pages++;
			workspace->strm.avail_out = PAGE_SIZE;
			workspace->strm.next_out = cpage_out;
		}
		/* we're all done */
		if (workspace->strm.total_in >= len)
			break;

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

			bytes_left = len - workspace->strm.total_in;
			kunmap(in_page);
			put_page(in_page);

			start += PAGE_SIZE;
			in_page = find_get_page(mapping,
						start >> PAGE_SHIFT);
			data_in = kmap(in_page);
			workspace->strm.avail_in = min(bytes_left,
							   PAGE_SIZE);
			workspace->strm.next_in = data_in;
		}
	}
	workspace->strm.avail_in = 0;
	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	zlib_deflateEnd(&workspace->strm);

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

	if (workspace->strm.total_out >= workspace->strm.total_in) {
		ret = -E2BIG;
		goto out;
	}

	ret = 0;
	*total_out = workspace->strm.total_out;
	*total_in = workspace->strm.total_in;
out:
	*out_pages = nr_pages;
	if (out_page)
		kunmap(out_page);

	if (in_page) {
		kunmap(in_page);
		put_page(in_page);
	}
	return ret;
}

static int zlib_decompress_bio(struct list_head *ws, struct page **pages_in,
				  u64 disk_start,
				  struct bio *orig_bio,
				  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 total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
	unsigned long buf_start;

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

	workspace->strm.total_out = 0;
	workspace->strm.next_out = workspace->buf;
	workspace->strm.avail_out = PAGE_SIZE;

	/* 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->strm.next_in += 2;
		workspace->strm.avail_in -= 2;
	}

	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
		pr_warn("BTRFS: inflateInit failed\n");
		kunmap(pages_in[page_in_index]);
		return -EIO;
	}
	while (workspace->strm.total_in < srclen) {
		ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
		if (ret != Z_OK && ret != Z_STREAM_END)
			break;

		buf_start = total_out;
		total_out = workspace->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,
						 orig_bio);
		if (ret2 == 0) {
			ret = 0;
			goto done;
		}

		workspace->strm.next_out = workspace->buf;
		workspace->strm.avail_out = PAGE_SIZE;

		if (workspace->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->strm.next_in = data_in;
			tmp = srclen - workspace->strm.total_in;
			workspace->strm.avail_in = min(tmp,
							   PAGE_SIZE);
		}
	}
	if (ret != Z_STREAM_END)
		ret = -EIO;
	else
		ret = 0;
done:
	zlib_inflateEnd(&workspace->strm);
	if (data_in)
		kunmap(pages_in[page_in_index]);
	if (!ret)
		zero_fill_bio(orig_bio);
	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;
	unsigned long total_out = 0;
	unsigned long pg_offset = 0;
	char *kaddr;

	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	bytes_left = destlen;

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

	workspace->strm.next_out = workspace->buf;
	workspace->strm.avail_out = PAGE_SIZE;
	workspace->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->strm.next_in += 2;
		workspace->strm.avail_in -= 2;
	}

	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
		pr_warn("BTRFS: inflateInit failed\n");
		return -EIO;
	}

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

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

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

		if (total_out == buf_start) {
			ret = -EIO;
			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_SIZE - pg_offset,
			    PAGE_SIZE - buf_offset);
		bytes = min(bytes, bytes_left);

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

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

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

	zlib_inflateEnd(&workspace->strm);

	/*
	 * this should only happen if zlib returned fewer bytes than we
	 * expected.  btrfs_get_block is responsible for zeroing from the
	 * end of the inline extent (destlen) to the end of the page
	 */
	if (pg_offset < destlen) {
		kaddr = kmap_atomic(dest_page);
		memset(kaddr + pg_offset, 0, destlen - pg_offset);
		kunmap_atomic(kaddr);
	}
	return ret;
}

const struct btrfs_compress_op btrfs_zlib_compress = {
	.alloc_workspace	= zlib_alloc_workspace,
	.free_workspace		= zlib_free_workspace,
	.compress_pages		= zlib_compress_pages,
	.decompress_bio		= zlib_decompress_bio,
	.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	35	struct workspace {
78809913	36	z_stream strm;
c8b97818 CM	37	char *buf;
	38	struct list_head list;
	39	};
	40
261507a0 LZ	41	static void zlib_free_workspace(struct list_head *ws)
	42	{
	43	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	44
78809913	45	vfree(workspace->strm.workspace);
261507a0 LZ	46	kfree(workspace->buf);
	47	kfree(workspace);
	48	}
	49
	50	static struct list_head *zlib_alloc_workspace(void)
c8b97818 CM	51	{
c8b97818 CM	52	struct workspace *workspace;
78809913	53	int workspacesize;
8844355d	54
c8b97818	55	workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
261507a0 LZ	56	if (!workspace)
261507a0 LZ	57	return ERR_PTR(-ENOMEM);
c8b97818	58
78809913 SS	59	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
	60	zlib_inflate_workspacesize());
	61	workspace->strm.workspace = vmalloc(workspacesize);
09cbfeaf	62	workspace->buf = kmalloc(PAGE_SIZE, GFP_NOFS);
78809913	63	if (!workspace->strm.workspace \|\| !workspace->buf)
261507a0	64	goto fail;
c8b97818	65
261507a0	66	INIT_LIST_HEAD(&workspace->list);
c8b97818	67
261507a0 LZ	68	return &workspace->list;
	69	fail:
	70	zlib_free_workspace(&workspace->list);
	71	return ERR_PTR(-ENOMEM);
c8b97818 CM	72	}
c8b97818 CM	73
261507a0 LZ	74	static int zlib_compress_pages(struct list_head *ws,
261507a0 LZ	75	struct address_space *mapping,
38c31464	76	u64 start,
261507a0	77	struct page **pages,
261507a0 LZ	78	unsigned long *out_pages,
	79	unsigned long *total_in,
	80	unsigned long *total_out,
	81	unsigned long max_out)
c8b97818	82	{
261507a0	83	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	84	int ret;
c8b97818 CM	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;
c8b97818	90	unsigned long bytes_left;
38c31464	91	unsigned long len = *total_out;
4d3a800e	92	unsigned long nr_dest_pages = *out_pages;
c8b97818 CM	93
	94	*out_pages = 0;
	95	*total_out = 0;
	96	*total_in = 0;
	97
78809913	98	if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
62e85577	99	pr_warn("BTRFS: deflateInit failed\n");
60e1975a	100	ret = -EIO;
c8b97818 CM	101	goto out;
	102	}
	103
78809913 SS	104	workspace->strm.total_in = 0;
78809913 SS	105	workspace->strm.total_out = 0;
c8b97818	106
09cbfeaf	107	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
c8b97818 CM	108	data_in = kmap(in_page);
	109
	110	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	111	if (out_page == NULL) {
60e1975a	112	ret = -ENOMEM;
4b72029d LZ	113	goto out;
4b72029d LZ	114	}
c8b97818 CM	115	cpage_out = kmap(out_page);
	116	pages[0] = out_page;
	117	nr_pages = 1;
	118
78809913 SS	119	workspace->strm.next_in = data_in;
78809913 SS	120	workspace->strm.next_out = cpage_out;
09cbfeaf KS	121	workspace->strm.avail_out = PAGE_SIZE;
09cbfeaf KS	122	workspace->strm.avail_in = min(len, PAGE_SIZE);
c8b97818	123
78809913 SS	124	while (workspace->strm.total_in < len) {
78809913 SS	125	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	126	if (ret != Z_OK) {
62e85577	127	pr_debug("BTRFS: deflate in loop returned %d\n",
c8b97818	128	ret);
78809913	129	zlib_deflateEnd(&workspace->strm);
60e1975a	130	ret = -EIO;
c8b97818 CM	131	goto out;
	132	}
	133
	134	/* we're making it bigger, give up */
78809913 SS	135	if (workspace->strm.total_in > 8192 &&
	136	workspace->strm.total_in <
	137	workspace->strm.total_out) {
130d5b41	138	ret = -E2BIG;
c8b97818 CM	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	*/
78809913	145	if (workspace->strm.avail_out == 0) {
c8b97818 CM	146	kunmap(out_page);
	147	if (nr_pages == nr_dest_pages) {
	148	out_page = NULL;
60e1975a	149	ret = -E2BIG;
c8b97818 CM	150	goto out;
	151	}
	152	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	153	if (out_page == NULL) {
60e1975a	154	ret = -ENOMEM;
4b72029d LZ	155	goto out;
4b72029d LZ	156	}
c8b97818 CM	157	cpage_out = kmap(out_page);
	158	pages[nr_pages] = out_page;
	159	nr_pages++;
09cbfeaf	160	workspace->strm.avail_out = PAGE_SIZE;
78809913	161	workspace->strm.next_out = cpage_out;
c8b97818 CM	162	}
c8b97818 CM	163	/* we're all done */
78809913	164	if (workspace->strm.total_in >= len)
c8b97818 CM	165	break;
	166
	167	/* we've read in a full page, get a new one */
78809913 SS	168	if (workspace->strm.avail_in == 0) {
78809913 SS	169	if (workspace->strm.total_out > max_out)
c8b97818 CM	170	break;
c8b97818 CM	171
78809913	172	bytes_left = len - workspace->strm.total_in;
c8b97818	173	kunmap(in_page);
09cbfeaf	174	put_page(in_page);
c8b97818	175
09cbfeaf	176	start += PAGE_SIZE;
c8b97818	177	in_page = find_get_page(mapping,
09cbfeaf	178	start >> PAGE_SHIFT);
c8b97818	179	data_in = kmap(in_page);
78809913	180	workspace->strm.avail_in = min(bytes_left,
09cbfeaf	181	PAGE_SIZE);
78809913	182	workspace->strm.next_in = data_in;
c8b97818 CM	183	}
c8b97818 CM	184	}
78809913 SS	185	workspace->strm.avail_in = 0;
	186	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	187	zlib_deflateEnd(&workspace->strm);
c8b97818 CM	188
c8b97818 CM	189	if (ret != Z_STREAM_END) {
60e1975a	190	ret = -EIO;
c8b97818 CM	191	goto out;
	192	}
	193
78809913	194	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	195	ret = -E2BIG;
c8b97818 CM	196	goto out;
	197	}
	198
	199	ret = 0;
78809913 SS	200	*total_out = workspace->strm.total_out;
78809913 SS	201	*total_in = workspace->strm.total_in;
c8b97818 CM	202	out:
	203	*out_pages = nr_pages;
	204	if (out_page)
	205	kunmap(out_page);
	206
	207	if (in_page) {
	208	kunmap(in_page);
09cbfeaf	209	put_page(in_page);
c8b97818	210	}
c8b97818 CM	211	return ret;
	212	}
	213
974b1adc	214	static int zlib_decompress_bio(struct list_head ws, struct page *pages_in,
261507a0	215	u64 disk_start,
974b1adc	216	struct bio *orig_bio,
261507a0	217	size_t srclen)
c8b97818	218	{
261507a0	219	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	220	int ret = 0, ret2;
c8b97818	221	int wbits = MAX_WBITS;
c8b97818 CM	222	char *data_in;
c8b97818 CM	223	size_t total_out = 0;
c8b97818	224	unsigned long page_in_index = 0;
09cbfeaf	225	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	226	unsigned long buf_start;
c8b97818	227
c8b97818	228	data_in = kmap(pages_in[page_in_index]);
78809913	229	workspace->strm.next_in = data_in;
09cbfeaf	230	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
78809913	231	workspace->strm.total_in = 0;
c8b97818	232
78809913 SS	233	workspace->strm.total_out = 0;
78809913 SS	234	workspace->strm.next_out = workspace->buf;
09cbfeaf	235	workspace->strm.avail_out = PAGE_SIZE;
c8b97818 CM	236
	237	/* If it's deflate, and it's got no preset dictionary, then
	238	we can tell zlib to skip the adler32 check. */
	239	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	240	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	241	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	242
	243	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	244	workspace->strm.next_in += 2;
78809913 SS	245	workspace->strm.avail_in -= 2;
c8b97818 CM	246	}
c8b97818 CM	247
78809913	248	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	249	pr_warn("BTRFS: inflateInit failed\n");
d1111a75	250	kunmap(pages_in[page_in_index]);
60e1975a	251	return -EIO;
c8b97818	252	}
78809913 SS	253	while (workspace->strm.total_in < srclen) {
78809913 SS	254	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	255	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	256	break;
c8b97818	257
3a39c18d	258	buf_start = total_out;
78809913	259	total_out = workspace->strm.total_out;
c8b97818	260
3a39c18d LZ	261	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	262	if (buf_start == total_out)
c8b97818	263	break;
c8b97818	264
3a39c18d LZ	265	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
3a39c18d LZ	266	total_out, disk_start,
974b1adc	267	orig_bio);
3a39c18d LZ	268	if (ret2 == 0) {
	269	ret = 0;
	270	goto done;
c8b97818	271	}
3a39c18d	272
78809913	273	workspace->strm.next_out = workspace->buf;
09cbfeaf	274	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	275
78809913	276	if (workspace->strm.avail_in == 0) {
c8b97818 CM	277	unsigned long tmp;
	278	kunmap(pages_in[page_in_index]);
	279	page_in_index++;
	280	if (page_in_index >= total_pages_in) {
	281	data_in = NULL;
	282	break;
	283	}
	284	data_in = kmap(pages_in[page_in_index]);
78809913 SS	285	workspace->strm.next_in = data_in;
	286	tmp = srclen - workspace->strm.total_in;
	287	workspace->strm.avail_in = min(tmp,
09cbfeaf	288	PAGE_SIZE);
c8b97818 CM	289	}
c8b97818 CM	290	}
d397712b	291	if (ret != Z_STREAM_END)
60e1975a	292	ret = -EIO;
d397712b	293	else
c8b97818	294	ret = 0;
c8b97818	295	done:
78809913	296	zlib_inflateEnd(&workspace->strm);
c8b97818 CM	297	if (data_in)
c8b97818 CM	298	kunmap(pages_in[page_in_index]);
2f19cad9	299	if (!ret)
974b1adc	300	zero_fill_bio(orig_bio);
c8b97818 CM	301	return ret;
	302	}
	303
261507a0 LZ	304	static int zlib_decompress(struct list_head ws, unsigned char data_in,
	305	struct page *dest_page,
	306	unsigned long start_byte,
	307	size_t srclen, size_t destlen)
c8b97818	308	{
261507a0	309	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	310	int ret = 0;
c8b97818 CM	311	int wbits = MAX_WBITS;
2f19cad9	312	unsigned long bytes_left;
c8b97818	313	unsigned long total_out = 0;
2f19cad9	314	unsigned long pg_offset = 0;
c8b97818 CM	315	char *kaddr;
c8b97818 CM	316
2f19cad9 CM	317	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	318	bytes_left = destlen;
	319
78809913 SS	320	workspace->strm.next_in = data_in;
	321	workspace->strm.avail_in = srclen;
	322	workspace->strm.total_in = 0;
c8b97818	323
78809913	324	workspace->strm.next_out = workspace->buf;
09cbfeaf	325	workspace->strm.avail_out = PAGE_SIZE;
78809913	326	workspace->strm.total_out = 0;
c8b97818 CM	327	/* If it's deflate, and it's got no preset dictionary, then
	328	we can tell zlib to skip the adler32 check. */
	329	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	330	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	331	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	332
	333	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	334	workspace->strm.next_in += 2;
78809913 SS	335	workspace->strm.avail_in -= 2;
c8b97818 CM	336	}
c8b97818 CM	337
78809913	338	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	339	pr_warn("BTRFS: inflateInit failed\n");
60e1975a	340	return -EIO;
c8b97818 CM	341	}
c8b97818 CM	342
d397712b	343	while (bytes_left > 0) {
c8b97818 CM	344	unsigned long buf_start;
	345	unsigned long buf_offset;
	346	unsigned long bytes;
c8b97818	347
78809913	348	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	349	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	350	break;
c8b97818 CM	351
c8b97818 CM	352	buf_start = total_out;
78809913	353	total_out = workspace->strm.total_out;
c8b97818 CM	354
c8b97818 CM	355	if (total_out == buf_start) {
60e1975a	356	ret = -EIO;
c8b97818 CM	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	367
09cbfeaf KS	368	bytes = min(PAGE_SIZE - pg_offset,
09cbfeaf KS	369	PAGE_SIZE - buf_offset);
c8b97818 CM	370	bytes = min(bytes, bytes_left);
c8b97818 CM	371
7ac687d9	372	kaddr = kmap_atomic(dest_page);
c8b97818	373	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
7ac687d9	374	kunmap_atomic(kaddr);
c8b97818 CM	375
	376	pg_offset += bytes;
	377	bytes_left -= bytes;
	378	next:
78809913	379	workspace->strm.next_out = workspace->buf;
09cbfeaf	380	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	381	}
d397712b CM	382
d397712b CM	383	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	384	ret = -EIO;
d397712b	385	else
c8b97818	386	ret = 0;
d397712b	387
78809913	388	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	389
	390	/*
	391	* this should only happen if zlib returned fewer bytes than we
	392	* expected. btrfs_get_block is responsible for zeroing from the
	393	* end of the inline extent (destlen) to the end of the page
	394	*/
	395	if (pg_offset < destlen) {
	396	kaddr = kmap_atomic(dest_page);
	397	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	398	kunmap_atomic(kaddr);
	399	}
c8b97818 CM	400	return ret;
	401	}
	402
e8c9f186	403	const struct btrfs_compress_op btrfs_zlib_compress = {
261507a0 LZ	404	.alloc_workspace = zlib_alloc_workspace,
	405	.free_workspace = zlib_free_workspace,
	406	.compress_pages = zlib_compress_pages,
974b1adc	407	.decompress_bio = zlib_decompress_bio,
261507a0 LZ	408	.decompress = zlib_decompress,
261507a0 LZ	409	};