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

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 *
 * Based on jffs2 zlib code:
 * Copyright © 2001-2007 Red Hat, Inc.
 * Created by David Woodhouse <[email protected]>
 */

#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;
	int level;
};

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, workspace->level)) {
		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;
}

static void zlib_set_level(struct list_head *ws, unsigned int type)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	unsigned level = (type & 0xF0) >> 4;

	if (level > 9)
		level = 9;

	workspace->level = level > 0 ? level : 3;
}

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,
	.set_level              = zlib_set_level,
};
Commit	Line	Data
c1d7c514	1	// SPDX-License-Identifier: GPL-2.0
c8b97818 CM	2	/*
	3	* Copyright (C) 2008 Oracle. All rights reserved.
	4	*
c8b97818 CM	5	* Based on jffs2 zlib code:
	6	* Copyright © 2001-2007 Red Hat, Inc.
	7	* Created by David Woodhouse <[email protected]>
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/slab.h>
	12	#include <linux/zlib.h>
	13	#include <linux/zutil.h>
6acafd1e	14	#include <linux/mm.h>
c8b97818 CM	15	#include <linux/init.h>
	16	#include <linux/err.h>
	17	#include <linux/sched.h>
	18	#include <linux/pagemap.h>
	19	#include <linux/bio.h>
e1ddce71	20	#include <linux/refcount.h>
b2950863	21	#include "compression.h"
c8b97818	22
c8b97818	23	struct workspace {
78809913	24	z_stream strm;
c8b97818 CM	25	char *buf;
c8b97818 CM	26	struct list_head list;
f51d2b59	27	int level;
c8b97818 CM	28	};
c8b97818 CM	29
261507a0 LZ	30	static void zlib_free_workspace(struct list_head *ws)
	31	{
	32	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	33
6acafd1e	34	kvfree(workspace->strm.workspace);
261507a0 LZ	35	kfree(workspace->buf);
	36	kfree(workspace);
	37	}
	38
	39	static struct list_head *zlib_alloc_workspace(void)
c8b97818 CM	40	{
c8b97818 CM	41	struct workspace *workspace;
78809913	42	int workspacesize;
8844355d	43
389a6cfc	44	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
261507a0 LZ	45	if (!workspace)
261507a0 LZ	46	return ERR_PTR(-ENOMEM);
c8b97818	47
78809913 SS	48	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
78809913 SS	49	zlib_inflate_workspacesize());
6acafd1e	50	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
389a6cfc	51	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
78809913	52	if (!workspace->strm.workspace \|\| !workspace->buf)
261507a0	53	goto fail;
c8b97818	54
261507a0	55	INIT_LIST_HEAD(&workspace->list);
c8b97818	56
261507a0 LZ	57	return &workspace->list;
	58	fail:
	59	zlib_free_workspace(&workspace->list);
	60	return ERR_PTR(-ENOMEM);
c8b97818 CM	61	}
c8b97818 CM	62
261507a0 LZ	63	static int zlib_compress_pages(struct list_head *ws,
261507a0 LZ	64	struct address_space *mapping,
38c31464	65	u64 start,
261507a0	66	struct page **pages,
261507a0 LZ	67	unsigned long *out_pages,
261507a0 LZ	68	unsigned long *total_in,
e5d74902	69	unsigned long *total_out)
c8b97818	70	{
261507a0	71	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	72	int ret;
c8b97818 CM	73	char *data_in;
	74	char *cpage_out;
	75	int nr_pages = 0;
	76	struct page *in_page = NULL;
	77	struct page *out_page = NULL;
c8b97818	78	unsigned long bytes_left;
38c31464	79	unsigned long len = *total_out;
4d3a800e	80	unsigned long nr_dest_pages = *out_pages;
e5d74902	81	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
c8b97818 CM	82
	83	*out_pages = 0;
	84	*total_out = 0;
	85	*total_in = 0;
	86
f51d2b59	87	if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
62e85577	88	pr_warn("BTRFS: deflateInit failed\n");
60e1975a	89	ret = -EIO;
c8b97818 CM	90	goto out;
	91	}
	92
78809913 SS	93	workspace->strm.total_in = 0;
78809913 SS	94	workspace->strm.total_out = 0;
c8b97818	95
09cbfeaf	96	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
c8b97818 CM	97	data_in = kmap(in_page);
	98
	99	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	100	if (out_page == NULL) {
60e1975a	101	ret = -ENOMEM;
4b72029d LZ	102	goto out;
4b72029d LZ	103	}
c8b97818 CM	104	cpage_out = kmap(out_page);
	105	pages[0] = out_page;
	106	nr_pages = 1;
	107
78809913 SS	108	workspace->strm.next_in = data_in;
78809913 SS	109	workspace->strm.next_out = cpage_out;
09cbfeaf KS	110	workspace->strm.avail_out = PAGE_SIZE;
09cbfeaf KS	111	workspace->strm.avail_in = min(len, PAGE_SIZE);
c8b97818	112
78809913 SS	113	while (workspace->strm.total_in < len) {
78809913 SS	114	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	115	if (ret != Z_OK) {
62e85577	116	pr_debug("BTRFS: deflate in loop returned %d\n",
c8b97818	117	ret);
78809913	118	zlib_deflateEnd(&workspace->strm);
60e1975a	119	ret = -EIO;
c8b97818 CM	120	goto out;
	121	}
	122
	123	/* we're making it bigger, give up */
78809913 SS	124	if (workspace->strm.total_in > 8192 &&
	125	workspace->strm.total_in <
	126	workspace->strm.total_out) {
130d5b41	127	ret = -E2BIG;
c8b97818 CM	128	goto out;
	129	}
	130	/* we need another page for writing out. Test this
	131	* before the total_in so we will pull in a new page for
	132	* the stream end if required
	133	*/
78809913	134	if (workspace->strm.avail_out == 0) {
c8b97818 CM	135	kunmap(out_page);
	136	if (nr_pages == nr_dest_pages) {
	137	out_page = NULL;
60e1975a	138	ret = -E2BIG;
c8b97818 CM	139	goto out;
	140	}
	141	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	142	if (out_page == NULL) {
60e1975a	143	ret = -ENOMEM;
4b72029d LZ	144	goto out;
4b72029d LZ	145	}
c8b97818 CM	146	cpage_out = kmap(out_page);
	147	pages[nr_pages] = out_page;
	148	nr_pages++;
09cbfeaf	149	workspace->strm.avail_out = PAGE_SIZE;
78809913	150	workspace->strm.next_out = cpage_out;
c8b97818 CM	151	}
c8b97818 CM	152	/* we're all done */
78809913	153	if (workspace->strm.total_in >= len)
c8b97818 CM	154	break;
	155
	156	/* we've read in a full page, get a new one */
78809913 SS	157	if (workspace->strm.avail_in == 0) {
78809913 SS	158	if (workspace->strm.total_out > max_out)
c8b97818 CM	159	break;
c8b97818 CM	160
78809913	161	bytes_left = len - workspace->strm.total_in;
c8b97818	162	kunmap(in_page);
09cbfeaf	163	put_page(in_page);
c8b97818	164
09cbfeaf	165	start += PAGE_SIZE;
c8b97818	166	in_page = find_get_page(mapping,
09cbfeaf	167	start >> PAGE_SHIFT);
c8b97818	168	data_in = kmap(in_page);
78809913	169	workspace->strm.avail_in = min(bytes_left,
09cbfeaf	170	PAGE_SIZE);
78809913	171	workspace->strm.next_in = data_in;
c8b97818 CM	172	}
c8b97818 CM	173	}
78809913 SS	174	workspace->strm.avail_in = 0;
	175	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	176	zlib_deflateEnd(&workspace->strm);
c8b97818 CM	177
c8b97818 CM	178	if (ret != Z_STREAM_END) {
60e1975a	179	ret = -EIO;
c8b97818 CM	180	goto out;
	181	}
	182
78809913	183	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	184	ret = -E2BIG;
c8b97818 CM	185	goto out;
	186	}
	187
	188	ret = 0;
78809913 SS	189	*total_out = workspace->strm.total_out;
78809913 SS	190	*total_in = workspace->strm.total_in;
c8b97818 CM	191	out:
	192	*out_pages = nr_pages;
	193	if (out_page)
	194	kunmap(out_page);
	195
	196	if (in_page) {
	197	kunmap(in_page);
09cbfeaf	198	put_page(in_page);
c8b97818	199	}
c8b97818 CM	200	return ret;
	201	}
	202
e1ddce71	203	static int zlib_decompress_bio(struct list_head ws, struct compressed_bio cb)
c8b97818	204	{
261507a0	205	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	206	int ret = 0, ret2;
c8b97818	207	int wbits = MAX_WBITS;
c8b97818 CM	208	char *data_in;
c8b97818 CM	209	size_t total_out = 0;
c8b97818	210	unsigned long page_in_index = 0;
e1ddce71	211	size_t srclen = cb->compressed_len;
09cbfeaf	212	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	213	unsigned long buf_start;
e1ddce71 AJ	214	struct page **pages_in = cb->compressed_pages;
	215	u64 disk_start = cb->start;
	216	struct bio *orig_bio = cb->orig_bio;
c8b97818	217
c8b97818	218	data_in = kmap(pages_in[page_in_index]);
78809913	219	workspace->strm.next_in = data_in;
09cbfeaf	220	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
78809913	221	workspace->strm.total_in = 0;
c8b97818	222
78809913 SS	223	workspace->strm.total_out = 0;
78809913 SS	224	workspace->strm.next_out = workspace->buf;
09cbfeaf	225	workspace->strm.avail_out = PAGE_SIZE;
c8b97818 CM	226
	227	/* If it's deflate, and it's got no preset dictionary, then
	228	we can tell zlib to skip the adler32 check. */
	229	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	230	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	231	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	232
	233	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	234	workspace->strm.next_in += 2;
78809913 SS	235	workspace->strm.avail_in -= 2;
c8b97818 CM	236	}
c8b97818 CM	237
78809913	238	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	239	pr_warn("BTRFS: inflateInit failed\n");
d1111a75	240	kunmap(pages_in[page_in_index]);
60e1975a	241	return -EIO;
c8b97818	242	}
78809913 SS	243	while (workspace->strm.total_in < srclen) {
78809913 SS	244	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	245	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	246	break;
c8b97818	247
3a39c18d	248	buf_start = total_out;
78809913	249	total_out = workspace->strm.total_out;
c8b97818	250
3a39c18d LZ	251	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	252	if (buf_start == total_out)
c8b97818	253	break;
c8b97818	254
3a39c18d LZ	255	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
3a39c18d LZ	256	total_out, disk_start,
974b1adc	257	orig_bio);
3a39c18d LZ	258	if (ret2 == 0) {
	259	ret = 0;
	260	goto done;
c8b97818	261	}
3a39c18d	262
78809913	263	workspace->strm.next_out = workspace->buf;
09cbfeaf	264	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	265
78809913	266	if (workspace->strm.avail_in == 0) {
c8b97818 CM	267	unsigned long tmp;
	268	kunmap(pages_in[page_in_index]);
	269	page_in_index++;
	270	if (page_in_index >= total_pages_in) {
	271	data_in = NULL;
	272	break;
	273	}
	274	data_in = kmap(pages_in[page_in_index]);
78809913 SS	275	workspace->strm.next_in = data_in;
	276	tmp = srclen - workspace->strm.total_in;
	277	workspace->strm.avail_in = min(tmp,
09cbfeaf	278	PAGE_SIZE);
c8b97818 CM	279	}
c8b97818 CM	280	}
d397712b	281	if (ret != Z_STREAM_END)
60e1975a	282	ret = -EIO;
d397712b	283	else
c8b97818	284	ret = 0;
c8b97818	285	done:
78809913	286	zlib_inflateEnd(&workspace->strm);
c8b97818 CM	287	if (data_in)
c8b97818 CM	288	kunmap(pages_in[page_in_index]);
2f19cad9	289	if (!ret)
974b1adc	290	zero_fill_bio(orig_bio);
c8b97818 CM	291	return ret;
	292	}
	293
261507a0 LZ	294	static int zlib_decompress(struct list_head ws, unsigned char data_in,
	295	struct page *dest_page,
	296	unsigned long start_byte,
	297	size_t srclen, size_t destlen)
c8b97818	298	{
261507a0	299	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	300	int ret = 0;
c8b97818 CM	301	int wbits = MAX_WBITS;
2f19cad9	302	unsigned long bytes_left;
c8b97818	303	unsigned long total_out = 0;
2f19cad9	304	unsigned long pg_offset = 0;
c8b97818 CM	305	char *kaddr;
c8b97818 CM	306
2f19cad9 CM	307	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	308	bytes_left = destlen;
	309
78809913 SS	310	workspace->strm.next_in = data_in;
	311	workspace->strm.avail_in = srclen;
	312	workspace->strm.total_in = 0;
c8b97818	313
78809913	314	workspace->strm.next_out = workspace->buf;
09cbfeaf	315	workspace->strm.avail_out = PAGE_SIZE;
78809913	316	workspace->strm.total_out = 0;
c8b97818 CM	317	/* If it's deflate, and it's got no preset dictionary, then
	318	we can tell zlib to skip the adler32 check. */
	319	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	320	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	321	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	322
	323	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	324	workspace->strm.next_in += 2;
78809913 SS	325	workspace->strm.avail_in -= 2;
c8b97818 CM	326	}
c8b97818 CM	327
78809913	328	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	329	pr_warn("BTRFS: inflateInit failed\n");
60e1975a	330	return -EIO;
c8b97818 CM	331	}
c8b97818 CM	332
d397712b	333	while (bytes_left > 0) {
c8b97818 CM	334	unsigned long buf_start;
	335	unsigned long buf_offset;
	336	unsigned long bytes;
c8b97818	337
78809913	338	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	339	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	340	break;
c8b97818 CM	341
c8b97818 CM	342	buf_start = total_out;
78809913	343	total_out = workspace->strm.total_out;
c8b97818 CM	344
c8b97818 CM	345	if (total_out == buf_start) {
60e1975a	346	ret = -EIO;
c8b97818 CM	347	break;
	348	}
	349
d397712b	350	if (total_out <= start_byte)
c8b97818	351	goto next;
c8b97818	352
d397712b	353	if (total_out > start_byte && buf_start < start_byte)
c8b97818	354	buf_offset = start_byte - buf_start;
d397712b	355	else
c8b97818	356	buf_offset = 0;
c8b97818	357
09cbfeaf KS	358	bytes = min(PAGE_SIZE - pg_offset,
09cbfeaf KS	359	PAGE_SIZE - buf_offset);
c8b97818 CM	360	bytes = min(bytes, bytes_left);
c8b97818 CM	361
7ac687d9	362	kaddr = kmap_atomic(dest_page);
c8b97818	363	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
7ac687d9	364	kunmap_atomic(kaddr);
c8b97818 CM	365
	366	pg_offset += bytes;
	367	bytes_left -= bytes;
	368	next:
78809913	369	workspace->strm.next_out = workspace->buf;
09cbfeaf	370	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	371	}
d397712b CM	372
d397712b CM	373	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	374	ret = -EIO;
d397712b	375	else
c8b97818	376	ret = 0;
d397712b	377
78809913	378	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	379
	380	/*
	381	* this should only happen if zlib returned fewer bytes than we
	382	* expected. btrfs_get_block is responsible for zeroing from the
	383	* end of the inline extent (destlen) to the end of the page
	384	*/
	385	if (pg_offset < destlen) {
	386	kaddr = kmap_atomic(dest_page);
	387	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	388	kunmap_atomic(kaddr);
	389	}
c8b97818 CM	390	return ret;
	391	}
	392
f51d2b59 DS	393	static void zlib_set_level(struct list_head *ws, unsigned int type)
	394	{
	395	struct workspace *workspace = list_entry(ws, struct workspace, list);
	396	unsigned level = (type & 0xF0) >> 4;
	397
	398	if (level > 9)
	399	level = 9;
	400
	401	workspace->level = level > 0 ? level : 3;
	402	}
	403
e8c9f186	404	const struct btrfs_compress_op btrfs_zlib_compress = {
261507a0 LZ	405	.alloc_workspace = zlib_alloc_workspace,
	406	.free_workspace = zlib_free_workspace,
	407	.compress_pages = zlib_compress_pages,
974b1adc	408	.decompress_bio = zlib_decompress_bio,
261507a0	409	.decompress = zlib_decompress,
f51d2b59	410	.set_level = zlib_set_level,
261507a0	411	};