[people/ms/linux.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, 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->strm, 3)) {
		printk(KERN_WARNING "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) {
			printk(KERN_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_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 = DIV_ROUND_UP(srclen, PAGE_SIZE);
	unsigned long buf_start;
	unsigned long pg_offset;

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

	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
		printk(KERN_WARNING "BTRFS: inflateInit failed\n");
		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,
						 bvec, vcnt,
						 &page_out_index, &pg_offset);
		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)
		btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
	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)) {
		printk(KERN_WARNING "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_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	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,
	75	struct address_space *mapping,
	76	u64 start, unsigned long len,
	77	struct page **pages,
	78	unsigned long nr_dest_pages,
	79	unsigned long *out_pages,
	80	unsigned long *total_in,
	81	unsigned long *total_out,
	82	unsigned long max_out)
c8b97818	83	{
261507a0	84	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	85	int ret;
c8b97818 CM	86	char *data_in;
	87	char *cpage_out;
	88	int nr_pages = 0;
	89	struct page *in_page = NULL;
	90	struct page *out_page = NULL;
c8b97818 CM	91	unsigned long bytes_left;
	92
	93	*out_pages = 0;
	94	*total_out = 0;
	95	*total_in = 0;
	96
78809913	97	if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
efe120a0	98	printk(KERN_WARNING "BTRFS: deflateInit failed\n");
60e1975a	99	ret = -EIO;
c8b97818 CM	100	goto out;
	101	}
	102
78809913 SS	103	workspace->strm.total_in = 0;
78809913 SS	104	workspace->strm.total_out = 0;
c8b97818	105
09cbfeaf	106	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
c8b97818 CM	107	data_in = kmap(in_page);
	108
	109	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	110	if (out_page == NULL) {
60e1975a	111	ret = -ENOMEM;
4b72029d LZ	112	goto out;
4b72029d LZ	113	}
c8b97818 CM	114	cpage_out = kmap(out_page);
	115	pages[0] = out_page;
	116	nr_pages = 1;
	117
78809913 SS	118	workspace->strm.next_in = data_in;
78809913 SS	119	workspace->strm.next_out = cpage_out;
09cbfeaf KS	120	workspace->strm.avail_out = PAGE_SIZE;
09cbfeaf KS	121	workspace->strm.avail_in = min(len, PAGE_SIZE);
c8b97818	122
78809913 SS	123	while (workspace->strm.total_in < len) {
78809913 SS	124	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	125	if (ret != Z_OK) {
efe120a0	126	printk(KERN_DEBUG "BTRFS: deflate in loop returned %d\n",
c8b97818	127	ret);
78809913	128	zlib_deflateEnd(&workspace->strm);
60e1975a	129	ret = -EIO;
c8b97818 CM	130	goto out;
	131	}
	132
	133	/* we're making it bigger, give up */
78809913 SS	134	if (workspace->strm.total_in > 8192 &&
	135	workspace->strm.total_in <
	136	workspace->strm.total_out) {
130d5b41	137	ret = -E2BIG;
c8b97818 CM	138	goto out;
	139	}
	140	/* we need another page for writing out. Test this
	141	* before the total_in so we will pull in a new page for
	142	* the stream end if required
	143	*/
78809913	144	if (workspace->strm.avail_out == 0) {
c8b97818 CM	145	kunmap(out_page);
	146	if (nr_pages == nr_dest_pages) {
	147	out_page = NULL;
60e1975a	148	ret = -E2BIG;
c8b97818 CM	149	goto out;
	150	}
	151	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	152	if (out_page == NULL) {
60e1975a	153	ret = -ENOMEM;
4b72029d LZ	154	goto out;
4b72029d LZ	155	}
c8b97818 CM	156	cpage_out = kmap(out_page);
	157	pages[nr_pages] = out_page;
	158	nr_pages++;
09cbfeaf	159	workspace->strm.avail_out = PAGE_SIZE;
78809913	160	workspace->strm.next_out = cpage_out;
c8b97818 CM	161	}
c8b97818 CM	162	/* we're all done */
78809913	163	if (workspace->strm.total_in >= len)
c8b97818 CM	164	break;
	165
	166	/* we've read in a full page, get a new one */
78809913 SS	167	if (workspace->strm.avail_in == 0) {
78809913 SS	168	if (workspace->strm.total_out > max_out)
c8b97818 CM	169	break;
c8b97818 CM	170
78809913	171	bytes_left = len - workspace->strm.total_in;
c8b97818	172	kunmap(in_page);
09cbfeaf	173	put_page(in_page);
c8b97818	174
09cbfeaf	175	start += PAGE_SIZE;
c8b97818	176	in_page = find_get_page(mapping,
09cbfeaf	177	start >> PAGE_SHIFT);
c8b97818	178	data_in = kmap(in_page);
78809913	179	workspace->strm.avail_in = min(bytes_left,
09cbfeaf	180	PAGE_SIZE);
78809913	181	workspace->strm.next_in = data_in;
c8b97818 CM	182	}
c8b97818 CM	183	}
78809913 SS	184	workspace->strm.avail_in = 0;
	185	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	186	zlib_deflateEnd(&workspace->strm);
c8b97818 CM	187
c8b97818 CM	188	if (ret != Z_STREAM_END) {
60e1975a	189	ret = -EIO;
c8b97818 CM	190	goto out;
	191	}
	192
78809913	193	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	194	ret = -E2BIG;
c8b97818 CM	195	goto out;
	196	}
	197
	198	ret = 0;
78809913 SS	199	*total_out = workspace->strm.total_out;
78809913 SS	200	*total_in = workspace->strm.total_in;
c8b97818 CM	201	out:
	202	*out_pages = nr_pages;
	203	if (out_page)
	204	kunmap(out_page);
	205
	206	if (in_page) {
	207	kunmap(in_page);
09cbfeaf	208	put_page(in_page);
c8b97818	209	}
c8b97818 CM	210	return ret;
	211	}
	212
261507a0 LZ	213	static int zlib_decompress_biovec(struct list_head ws, struct page *pages_in,
	214	u64 disk_start,
	215	struct bio_vec *bvec,
	216	int vcnt,
	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 CM	224	unsigned long page_in_index = 0;
c8b97818 CM	225	unsigned long page_out_index = 0;
09cbfeaf	226	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	227	unsigned long buf_start;
c8b97818	228	unsigned long pg_offset;
c8b97818	229
c8b97818	230	data_in = kmap(pages_in[page_in_index]);
78809913	231	workspace->strm.next_in = data_in;
09cbfeaf	232	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
78809913	233	workspace->strm.total_in = 0;
c8b97818	234
78809913 SS	235	workspace->strm.total_out = 0;
78809913 SS	236	workspace->strm.next_out = workspace->buf;
09cbfeaf	237	workspace->strm.avail_out = PAGE_SIZE;
c8b97818 CM	238	pg_offset = 0;
	239
	240	/* If it's deflate, and it's got no preset dictionary, then
	241	we can tell zlib to skip the adler32 check. */
	242	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	243	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	244	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	245
	246	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	247	workspace->strm.next_in += 2;
78809913 SS	248	workspace->strm.avail_in -= 2;
c8b97818 CM	249	}
c8b97818 CM	250
78809913	251	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
efe120a0	252	printk(KERN_WARNING "BTRFS: inflateInit failed\n");
60e1975a	253	return -EIO;
c8b97818	254	}
78809913 SS	255	while (workspace->strm.total_in < srclen) {
78809913 SS	256	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	257	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	258	break;
c8b97818	259
3a39c18d	260	buf_start = total_out;
78809913	261	total_out = workspace->strm.total_out;
c8b97818	262
3a39c18d LZ	263	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	264	if (buf_start == total_out)
c8b97818	265	break;
c8b97818	266
3a39c18d LZ	267	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
	268	total_out, disk_start,
	269	bvec, vcnt,
	270	&page_out_index, &pg_offset);
	271	if (ret2 == 0) {
	272	ret = 0;
	273	goto done;
c8b97818	274	}
3a39c18d	275
78809913	276	workspace->strm.next_out = workspace->buf;
09cbfeaf	277	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	278
78809913	279	if (workspace->strm.avail_in == 0) {
c8b97818 CM	280	unsigned long tmp;
	281	kunmap(pages_in[page_in_index]);
	282	page_in_index++;
	283	if (page_in_index >= total_pages_in) {
	284	data_in = NULL;
	285	break;
	286	}
	287	data_in = kmap(pages_in[page_in_index]);
78809913 SS	288	workspace->strm.next_in = data_in;
	289	tmp = srclen - workspace->strm.total_in;
	290	workspace->strm.avail_in = min(tmp,
09cbfeaf	291	PAGE_SIZE);
c8b97818 CM	292	}
c8b97818 CM	293	}
d397712b	294	if (ret != Z_STREAM_END)
60e1975a	295	ret = -EIO;
d397712b	296	else
c8b97818	297	ret = 0;
c8b97818	298	done:
78809913	299	zlib_inflateEnd(&workspace->strm);
c8b97818 CM	300	if (data_in)
c8b97818 CM	301	kunmap(pages_in[page_in_index]);
2f19cad9 CM	302	if (!ret)
2f19cad9 CM	303	btrfs_clear_biovec_end(bvec, vcnt, page_out_index, pg_offset);
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;
2f19cad9	315	unsigned long bytes_left;
c8b97818	316	unsigned long total_out = 0;
2f19cad9	317	unsigned long pg_offset = 0;
c8b97818 CM	318	char *kaddr;
c8b97818 CM	319
2f19cad9 CM	320	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	321	bytes_left = destlen;
	322
78809913 SS	323	workspace->strm.next_in = data_in;
	324	workspace->strm.avail_in = srclen;
	325	workspace->strm.total_in = 0;
c8b97818	326
78809913	327	workspace->strm.next_out = workspace->buf;
09cbfeaf	328	workspace->strm.avail_out = PAGE_SIZE;
78809913	329	workspace->strm.total_out = 0;
c8b97818 CM	330	/* If it's deflate, and it's got no preset dictionary, then
	331	we can tell zlib to skip the adler32 check. */
	332	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	333	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	334	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	335
	336	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	337	workspace->strm.next_in += 2;
78809913 SS	338	workspace->strm.avail_in -= 2;
c8b97818 CM	339	}
c8b97818 CM	340
78809913	341	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
efe120a0	342	printk(KERN_WARNING "BTRFS: inflateInit failed\n");
60e1975a	343	return -EIO;
c8b97818 CM	344	}
c8b97818 CM	345
d397712b	346	while (bytes_left > 0) {
c8b97818 CM	347	unsigned long buf_start;
	348	unsigned long buf_offset;
	349	unsigned long bytes;
c8b97818	350
78809913	351	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	352	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	353	break;
c8b97818 CM	354
c8b97818 CM	355	buf_start = total_out;
78809913	356	total_out = workspace->strm.total_out;
c8b97818 CM	357
c8b97818 CM	358	if (total_out == buf_start) {
60e1975a	359	ret = -EIO;
c8b97818 CM	360	break;
	361	}
	362
d397712b	363	if (total_out <= start_byte)
c8b97818	364	goto next;
c8b97818	365
d397712b	366	if (total_out > start_byte && buf_start < start_byte)
c8b97818	367	buf_offset = start_byte - buf_start;
d397712b	368	else
c8b97818	369	buf_offset = 0;
c8b97818	370
09cbfeaf KS	371	bytes = min(PAGE_SIZE - pg_offset,
09cbfeaf KS	372	PAGE_SIZE - buf_offset);
c8b97818 CM	373	bytes = min(bytes, bytes_left);
c8b97818 CM	374
7ac687d9	375	kaddr = kmap_atomic(dest_page);
c8b97818	376	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
7ac687d9	377	kunmap_atomic(kaddr);
c8b97818 CM	378
	379	pg_offset += bytes;
	380	bytes_left -= bytes;
	381	next:
78809913	382	workspace->strm.next_out = workspace->buf;
09cbfeaf	383	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	384	}
d397712b CM	385
d397712b CM	386	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	387	ret = -EIO;
d397712b	388	else
c8b97818	389	ret = 0;
d397712b	390
78809913	391	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	392
	393	/*
	394	* this should only happen if zlib returned fewer bytes than we
	395	* expected. btrfs_get_block is responsible for zeroing from the
	396	* end of the inline extent (destlen) to the end of the page
	397	*/
	398	if (pg_offset < destlen) {
	399	kaddr = kmap_atomic(dest_page);
	400	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	401	kunmap_atomic(kaddr);
	402	}
c8b97818 CM	403	return ret;
	404	}
	405
e8c9f186	406	const struct btrfs_compress_op btrfs_zlib_compress = {
261507a0 LZ	407	.alloc_workspace = zlib_alloc_workspace,
	408	.free_workspace = zlib_free_workspace,
	409	.compress_pages = zlib_compress_pages,
	410	.decompress_biovec = zlib_decompress_biovec,
	411	.decompress = zlib_decompress,
	412	};