[mirror_ubuntu-artful-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/mm.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include <linux/bio.h>
#include <linux/refcount.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);

	kvfree(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_KERNEL);
	if (!workspace)
		return ERR_PTR(-ENOMEM);

	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
			zlib_inflate_workspacesize());
	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	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)
{
	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;
	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;

	*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 compressed_bio *cb)
{
	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;
	size_t srclen = cb->compressed_len;
	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
	unsigned long buf_start;
	struct page **pages_in = cb->compressed_pages;
	u64 disk_start = cb->start;
	struct bio *orig_bio = cb->orig_bio;

	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>
6acafd1e	27	#include <linux/mm.h>
c8b97818 CM	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>
e1ddce71	33	#include <linux/refcount.h>
b2950863	34	#include "compression.h"
c8b97818	35
c8b97818	36	struct workspace {
78809913	37	z_stream strm;
c8b97818 CM	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
6acafd1e	46	kvfree(workspace->strm.workspace);
261507a0 LZ	47	kfree(workspace->buf);
	48	kfree(workspace);
	49	}
	50
	51	static struct list_head *zlib_alloc_workspace(void)
c8b97818 CM	52	{
c8b97818 CM	53	struct workspace *workspace;
78809913	54	int workspacesize;
8844355d	55
389a6cfc	56	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
261507a0 LZ	57	if (!workspace)
261507a0 LZ	58	return ERR_PTR(-ENOMEM);
c8b97818	59
78809913 SS	60	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
78809913 SS	61	zlib_inflate_workspacesize());
6acafd1e	62	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
389a6cfc	63	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
78809913	64	if (!workspace->strm.workspace \|\| !workspace->buf)
261507a0	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,
261507a0 LZ	76	struct address_space *mapping,
38c31464	77	u64 start,
261507a0	78	struct page **pages,
261507a0 LZ	79	unsigned long *out_pages,
261507a0 LZ	80	unsigned long *total_in,
e5d74902	81	unsigned long *total_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;
e5d74902	93	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
c8b97818 CM	94
	95	*out_pages = 0;
	96	*total_out = 0;
	97	*total_in = 0;
	98
78809913	99	if (Z_OK != zlib_deflateInit(&workspace->strm, 3)) {
62e85577	100	pr_warn("BTRFS: deflateInit failed\n");
60e1975a	101	ret = -EIO;
c8b97818 CM	102	goto out;
	103	}
	104
78809913 SS	105	workspace->strm.total_in = 0;
78809913 SS	106	workspace->strm.total_out = 0;
c8b97818	107
09cbfeaf	108	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
c8b97818 CM	109	data_in = kmap(in_page);
	110
	111	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	112	if (out_page == NULL) {
60e1975a	113	ret = -ENOMEM;
4b72029d LZ	114	goto out;
4b72029d LZ	115	}
c8b97818 CM	116	cpage_out = kmap(out_page);
	117	pages[0] = out_page;
	118	nr_pages = 1;
	119
78809913 SS	120	workspace->strm.next_in = data_in;
78809913 SS	121	workspace->strm.next_out = cpage_out;
09cbfeaf KS	122	workspace->strm.avail_out = PAGE_SIZE;
09cbfeaf KS	123	workspace->strm.avail_in = min(len, PAGE_SIZE);
c8b97818	124
78809913 SS	125	while (workspace->strm.total_in < len) {
78809913 SS	126	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	127	if (ret != Z_OK) {
62e85577	128	pr_debug("BTRFS: deflate in loop returned %d\n",
c8b97818	129	ret);
78809913	130	zlib_deflateEnd(&workspace->strm);
60e1975a	131	ret = -EIO;
c8b97818 CM	132	goto out;
	133	}
	134
	135	/* we're making it bigger, give up */
78809913 SS	136	if (workspace->strm.total_in > 8192 &&
	137	workspace->strm.total_in <
	138	workspace->strm.total_out) {
130d5b41	139	ret = -E2BIG;
c8b97818 CM	140	goto out;
	141	}
	142	/* we need another page for writing out. Test this
	143	* before the total_in so we will pull in a new page for
	144	* the stream end if required
	145	*/
78809913	146	if (workspace->strm.avail_out == 0) {
c8b97818 CM	147	kunmap(out_page);
	148	if (nr_pages == nr_dest_pages) {
	149	out_page = NULL;
60e1975a	150	ret = -E2BIG;
c8b97818 CM	151	goto out;
	152	}
	153	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	154	if (out_page == NULL) {
60e1975a	155	ret = -ENOMEM;
4b72029d LZ	156	goto out;
4b72029d LZ	157	}
c8b97818 CM	158	cpage_out = kmap(out_page);
	159	pages[nr_pages] = out_page;
	160	nr_pages++;
09cbfeaf	161	workspace->strm.avail_out = PAGE_SIZE;
78809913	162	workspace->strm.next_out = cpage_out;
c8b97818 CM	163	}
c8b97818 CM	164	/* we're all done */
78809913	165	if (workspace->strm.total_in >= len)
c8b97818 CM	166	break;
	167
	168	/* we've read in a full page, get a new one */
78809913 SS	169	if (workspace->strm.avail_in == 0) {
78809913 SS	170	if (workspace->strm.total_out > max_out)
c8b97818 CM	171	break;
c8b97818 CM	172
78809913	173	bytes_left = len - workspace->strm.total_in;
c8b97818	174	kunmap(in_page);
09cbfeaf	175	put_page(in_page);
c8b97818	176
09cbfeaf	177	start += PAGE_SIZE;
c8b97818	178	in_page = find_get_page(mapping,
09cbfeaf	179	start >> PAGE_SHIFT);
c8b97818	180	data_in = kmap(in_page);
78809913	181	workspace->strm.avail_in = min(bytes_left,
09cbfeaf	182	PAGE_SIZE);
78809913	183	workspace->strm.next_in = data_in;
c8b97818 CM	184	}
c8b97818 CM	185	}
78809913 SS	186	workspace->strm.avail_in = 0;
	187	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	188	zlib_deflateEnd(&workspace->strm);
c8b97818 CM	189
c8b97818 CM	190	if (ret != Z_STREAM_END) {
60e1975a	191	ret = -EIO;
c8b97818 CM	192	goto out;
	193	}
	194
78809913	195	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	196	ret = -E2BIG;
c8b97818 CM	197	goto out;
	198	}
	199
	200	ret = 0;
78809913 SS	201	*total_out = workspace->strm.total_out;
78809913 SS	202	*total_in = workspace->strm.total_in;
c8b97818 CM	203	out:
	204	*out_pages = nr_pages;
	205	if (out_page)
	206	kunmap(out_page);
	207
	208	if (in_page) {
	209	kunmap(in_page);
09cbfeaf	210	put_page(in_page);
c8b97818	211	}
c8b97818 CM	212	return ret;
	213	}
	214
e1ddce71	215	static int zlib_decompress_bio(struct list_head ws, struct compressed_bio cb)
c8b97818	216	{
261507a0	217	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	218	int ret = 0, ret2;
c8b97818	219	int wbits = MAX_WBITS;
c8b97818 CM	220	char *data_in;
c8b97818 CM	221	size_t total_out = 0;
c8b97818	222	unsigned long page_in_index = 0;
e1ddce71	223	size_t srclen = cb->compressed_len;
09cbfeaf	224	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	225	unsigned long buf_start;
e1ddce71 AJ	226	struct page **pages_in = cb->compressed_pages;
	227	u64 disk_start = cb->start;
	228	struct bio *orig_bio = cb->orig_bio;
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
	239	/* If it's deflate, and it's got no preset dictionary, then
	240	we can tell zlib to skip the adler32 check. */
	241	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	242	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	243	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	244
	245	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	246	workspace->strm.next_in += 2;
78809913 SS	247	workspace->strm.avail_in -= 2;
c8b97818 CM	248	}
c8b97818 CM	249
78809913	250	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	251	pr_warn("BTRFS: inflateInit failed\n");
d1111a75	252	kunmap(pages_in[page_in_index]);
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,
3a39c18d LZ	268	total_out, disk_start,
974b1adc	269	orig_bio);
3a39c18d LZ	270	if (ret2 == 0) {
	271	ret = 0;
	272	goto done;
c8b97818	273	}
3a39c18d	274
78809913	275	workspace->strm.next_out = workspace->buf;
09cbfeaf	276	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	277
78809913	278	if (workspace->strm.avail_in == 0) {
c8b97818 CM	279	unsigned long tmp;
	280	kunmap(pages_in[page_in_index]);
	281	page_in_index++;
	282	if (page_in_index >= total_pages_in) {
	283	data_in = NULL;
	284	break;
	285	}
	286	data_in = kmap(pages_in[page_in_index]);
78809913 SS	287	workspace->strm.next_in = data_in;
	288	tmp = srclen - workspace->strm.total_in;
	289	workspace->strm.avail_in = min(tmp,
09cbfeaf	290	PAGE_SIZE);
c8b97818 CM	291	}
c8b97818 CM	292	}
d397712b	293	if (ret != Z_STREAM_END)
60e1975a	294	ret = -EIO;
d397712b	295	else
c8b97818	296	ret = 0;
c8b97818	297	done:
78809913	298	zlib_inflateEnd(&workspace->strm);
c8b97818 CM	299	if (data_in)
c8b97818 CM	300	kunmap(pages_in[page_in_index]);
2f19cad9	301	if (!ret)
974b1adc	302	zero_fill_bio(orig_bio);
c8b97818 CM	303	return ret;
	304	}
	305
261507a0 LZ	306	static int zlib_decompress(struct list_head ws, unsigned char data_in,
	307	struct page *dest_page,
	308	unsigned long start_byte,
	309	size_t srclen, size_t destlen)
c8b97818	310	{
261507a0	311	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	312	int ret = 0;
c8b97818 CM	313	int wbits = MAX_WBITS;
2f19cad9	314	unsigned long bytes_left;
c8b97818	315	unsigned long total_out = 0;
2f19cad9	316	unsigned long pg_offset = 0;
c8b97818 CM	317	char *kaddr;
c8b97818 CM	318
2f19cad9 CM	319	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	320	bytes_left = destlen;
	321
78809913 SS	322	workspace->strm.next_in = data_in;
	323	workspace->strm.avail_in = srclen;
	324	workspace->strm.total_in = 0;
c8b97818	325
78809913	326	workspace->strm.next_out = workspace->buf;
09cbfeaf	327	workspace->strm.avail_out = PAGE_SIZE;
78809913	328	workspace->strm.total_out = 0;
c8b97818 CM	329	/* If it's deflate, and it's got no preset dictionary, then
	330	we can tell zlib to skip the adler32 check. */
	331	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	332	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	333	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	334
	335	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	336	workspace->strm.next_in += 2;
78809913 SS	337	workspace->strm.avail_in -= 2;
c8b97818 CM	338	}
c8b97818 CM	339
78809913	340	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	341	pr_warn("BTRFS: inflateInit failed\n");
60e1975a	342	return -EIO;
c8b97818 CM	343	}
c8b97818 CM	344
d397712b	345	while (bytes_left > 0) {
c8b97818 CM	346	unsigned long buf_start;
	347	unsigned long buf_offset;
	348	unsigned long bytes;
c8b97818	349
78809913	350	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	351	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	352	break;
c8b97818 CM	353
c8b97818 CM	354	buf_start = total_out;
78809913	355	total_out = workspace->strm.total_out;
c8b97818 CM	356
c8b97818 CM	357	if (total_out == buf_start) {
60e1975a	358	ret = -EIO;
c8b97818 CM	359	break;
	360	}
	361
d397712b	362	if (total_out <= start_byte)
c8b97818	363	goto next;
c8b97818	364
d397712b	365	if (total_out > start_byte && buf_start < start_byte)
c8b97818	366	buf_offset = start_byte - buf_start;
d397712b	367	else
c8b97818	368	buf_offset = 0;
c8b97818	369
09cbfeaf KS	370	bytes = min(PAGE_SIZE - pg_offset,
09cbfeaf KS	371	PAGE_SIZE - buf_offset);
c8b97818 CM	372	bytes = min(bytes, bytes_left);
c8b97818 CM	373
7ac687d9	374	kaddr = kmap_atomic(dest_page);
c8b97818	375	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
7ac687d9	376	kunmap_atomic(kaddr);
c8b97818 CM	377
	378	pg_offset += bytes;
	379	bytes_left -= bytes;
	380	next:
78809913	381	workspace->strm.next_out = workspace->buf;
09cbfeaf	382	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	383	}
d397712b CM	384
d397712b CM	385	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	386	ret = -EIO;
d397712b	387	else
c8b97818	388	ret = 0;
d397712b	389
78809913	390	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	391
	392	/*
	393	* this should only happen if zlib returned fewer bytes than we
	394	* expected. btrfs_get_block is responsible for zeroing from the
	395	* end of the inline extent (destlen) to the end of the page
	396	*/
	397	if (pg_offset < destlen) {
	398	kaddr = kmap_atomic(dest_page);
	399	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	400	kunmap_atomic(kaddr);
	401	}
c8b97818 CM	402	return ret;
	403	}
	404
e8c9f186	405	const struct btrfs_compress_op btrfs_zlib_compress = {
261507a0 LZ	406	.alloc_workspace = zlib_alloc_workspace,
	407	.free_workspace = zlib_free_workspace,
	408	.compress_pages = zlib_compress_pages,
974b1adc	409	.decompress_bio = zlib_decompress_bio,
261507a0 LZ	410	.decompress = zlib_decompress,
261507a0 LZ	411	};