[linux-block.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 <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;
	int level;
};

static struct workspace_manager wsm;

static void zlib_init_workspace_manager(void)
{
	btrfs_init_workspace_manager(&wsm, &btrfs_zlib_compress);
}

static void zlib_cleanup_workspace_manager(void)
{
	btrfs_cleanup_workspace_manager(&wsm);
}

static struct list_head *zlib_get_workspace(void)
{
	return btrfs_get_workspace(&wsm);
}

static void zlib_put_workspace(struct list_head *ws)
{
	btrfs_put_workspace(&wsm, ws);
}

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 int level = btrfs_compress_level(type);

	if (level > 9)
		level = 9;

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

const struct btrfs_compress_op btrfs_zlib_compress = {
	.init_workspace_manager	= zlib_init_workspace_manager,
	.cleanup_workspace_manager = zlib_cleanup_workspace_manager,
	.get_workspace		= zlib_get_workspace,
	.put_workspace		= zlib_put_workspace,
	.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 <dwmw2@infradead.org>
	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
92ee5530 DZ	30	static struct workspace_manager wsm;
	31
	32	static void zlib_init_workspace_manager(void)
	33	{
	34	btrfs_init_workspace_manager(&wsm, &btrfs_zlib_compress);
	35	}
	36
	37	static void zlib_cleanup_workspace_manager(void)
	38	{
	39	btrfs_cleanup_workspace_manager(&wsm);
	40	}
	41
	42	static struct list_head *zlib_get_workspace(void)
	43	{
	44	return btrfs_get_workspace(&wsm);
	45	}
	46
	47	static void zlib_put_workspace(struct list_head *ws)
	48	{
	49	btrfs_put_workspace(&wsm, ws);
	50	}
	51
261507a0 LZ	52	static void zlib_free_workspace(struct list_head *ws)
	53	{
	54	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	55
6acafd1e	56	kvfree(workspace->strm.workspace);
261507a0 LZ	57	kfree(workspace->buf);
	58	kfree(workspace);
	59	}
	60
	61	static struct list_head *zlib_alloc_workspace(void)
c8b97818 CM	62	{
c8b97818 CM	63	struct workspace *workspace;
78809913	64	int workspacesize;
8844355d	65
389a6cfc	66	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
261507a0 LZ	67	if (!workspace)
261507a0 LZ	68	return ERR_PTR(-ENOMEM);
c8b97818	69
78809913 SS	70	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
78809913 SS	71	zlib_inflate_workspacesize());
6acafd1e	72	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
389a6cfc	73	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
78809913	74	if (!workspace->strm.workspace \|\| !workspace->buf)
261507a0	75	goto fail;
c8b97818	76
261507a0	77	INIT_LIST_HEAD(&workspace->list);
c8b97818	78
261507a0 LZ	79	return &workspace->list;
	80	fail:
	81	zlib_free_workspace(&workspace->list);
	82	return ERR_PTR(-ENOMEM);
c8b97818 CM	83	}
c8b97818 CM	84
261507a0 LZ	85	static int zlib_compress_pages(struct list_head *ws,
261507a0 LZ	86	struct address_space *mapping,
38c31464	87	u64 start,
261507a0	88	struct page **pages,
261507a0 LZ	89	unsigned long *out_pages,
261507a0 LZ	90	unsigned long *total_in,
e5d74902	91	unsigned long *total_out)
c8b97818	92	{
261507a0	93	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	94	int ret;
c8b97818 CM	95	char *data_in;
	96	char *cpage_out;
	97	int nr_pages = 0;
	98	struct page *in_page = NULL;
	99	struct page *out_page = NULL;
c8b97818	100	unsigned long bytes_left;
38c31464	101	unsigned long len = *total_out;
4d3a800e	102	unsigned long nr_dest_pages = *out_pages;
e5d74902	103	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
c8b97818 CM	104
	105	*out_pages = 0;
	106	*total_out = 0;
	107	*total_in = 0;
	108
f51d2b59	109	if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
62e85577	110	pr_warn("BTRFS: deflateInit failed\n");
60e1975a	111	ret = -EIO;
c8b97818 CM	112	goto out;
	113	}
	114
78809913 SS	115	workspace->strm.total_in = 0;
78809913 SS	116	workspace->strm.total_out = 0;
c8b97818	117
09cbfeaf	118	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
c8b97818 CM	119	data_in = kmap(in_page);
	120
	121	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	122	if (out_page == NULL) {
60e1975a	123	ret = -ENOMEM;
4b72029d LZ	124	goto out;
4b72029d LZ	125	}
c8b97818 CM	126	cpage_out = kmap(out_page);
	127	pages[0] = out_page;
	128	nr_pages = 1;
	129
78809913 SS	130	workspace->strm.next_in = data_in;
78809913 SS	131	workspace->strm.next_out = cpage_out;
09cbfeaf KS	132	workspace->strm.avail_out = PAGE_SIZE;
09cbfeaf KS	133	workspace->strm.avail_in = min(len, PAGE_SIZE);
c8b97818	134
78809913 SS	135	while (workspace->strm.total_in < len) {
78809913 SS	136	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	137	if (ret != Z_OK) {
62e85577	138	pr_debug("BTRFS: deflate in loop returned %d\n",
c8b97818	139	ret);
78809913	140	zlib_deflateEnd(&workspace->strm);
60e1975a	141	ret = -EIO;
c8b97818 CM	142	goto out;
	143	}
	144
	145	/* we're making it bigger, give up */
78809913 SS	146	if (workspace->strm.total_in > 8192 &&
	147	workspace->strm.total_in <
	148	workspace->strm.total_out) {
130d5b41	149	ret = -E2BIG;
c8b97818 CM	150	goto out;
	151	}
	152	/* we need another page for writing out. Test this
	153	* before the total_in so we will pull in a new page for
	154	* the stream end if required
	155	*/
78809913	156	if (workspace->strm.avail_out == 0) {
c8b97818 CM	157	kunmap(out_page);
	158	if (nr_pages == nr_dest_pages) {
	159	out_page = NULL;
60e1975a	160	ret = -E2BIG;
c8b97818 CM	161	goto out;
	162	}
	163	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	164	if (out_page == NULL) {
60e1975a	165	ret = -ENOMEM;
4b72029d LZ	166	goto out;
4b72029d LZ	167	}
c8b97818 CM	168	cpage_out = kmap(out_page);
	169	pages[nr_pages] = out_page;
	170	nr_pages++;
09cbfeaf	171	workspace->strm.avail_out = PAGE_SIZE;
78809913	172	workspace->strm.next_out = cpage_out;
c8b97818 CM	173	}
c8b97818 CM	174	/* we're all done */
78809913	175	if (workspace->strm.total_in >= len)
c8b97818 CM	176	break;
	177
	178	/* we've read in a full page, get a new one */
78809913 SS	179	if (workspace->strm.avail_in == 0) {
78809913 SS	180	if (workspace->strm.total_out > max_out)
c8b97818 CM	181	break;
c8b97818 CM	182
78809913	183	bytes_left = len - workspace->strm.total_in;
c8b97818	184	kunmap(in_page);
09cbfeaf	185	put_page(in_page);
c8b97818	186
09cbfeaf	187	start += PAGE_SIZE;
c8b97818	188	in_page = find_get_page(mapping,
09cbfeaf	189	start >> PAGE_SHIFT);
c8b97818	190	data_in = kmap(in_page);
78809913	191	workspace->strm.avail_in = min(bytes_left,
09cbfeaf	192	PAGE_SIZE);
78809913	193	workspace->strm.next_in = data_in;
c8b97818 CM	194	}
c8b97818 CM	195	}
78809913 SS	196	workspace->strm.avail_in = 0;
	197	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	198	zlib_deflateEnd(&workspace->strm);
c8b97818 CM	199
c8b97818 CM	200	if (ret != Z_STREAM_END) {
60e1975a	201	ret = -EIO;
c8b97818 CM	202	goto out;
	203	}
	204
78809913	205	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	206	ret = -E2BIG;
c8b97818 CM	207	goto out;
	208	}
	209
	210	ret = 0;
78809913 SS	211	*total_out = workspace->strm.total_out;
78809913 SS	212	*total_in = workspace->strm.total_in;
c8b97818 CM	213	out:
	214	*out_pages = nr_pages;
	215	if (out_page)
	216	kunmap(out_page);
	217
	218	if (in_page) {
	219	kunmap(in_page);
09cbfeaf	220	put_page(in_page);
c8b97818	221	}
c8b97818 CM	222	return ret;
	223	}
	224
e1ddce71	225	static int zlib_decompress_bio(struct list_head ws, struct compressed_bio cb)
c8b97818	226	{
261507a0	227	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	228	int ret = 0, ret2;
c8b97818	229	int wbits = MAX_WBITS;
c8b97818 CM	230	char *data_in;
c8b97818 CM	231	size_t total_out = 0;
c8b97818	232	unsigned long page_in_index = 0;
e1ddce71	233	size_t srclen = cb->compressed_len;
09cbfeaf	234	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	235	unsigned long buf_start;
e1ddce71 AJ	236	struct page **pages_in = cb->compressed_pages;
	237	u64 disk_start = cb->start;
	238	struct bio *orig_bio = cb->orig_bio;
c8b97818	239
c8b97818	240	data_in = kmap(pages_in[page_in_index]);
78809913	241	workspace->strm.next_in = data_in;
09cbfeaf	242	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
78809913	243	workspace->strm.total_in = 0;
c8b97818	244
78809913 SS	245	workspace->strm.total_out = 0;
78809913 SS	246	workspace->strm.next_out = workspace->buf;
09cbfeaf	247	workspace->strm.avail_out = PAGE_SIZE;
c8b97818 CM	248
	249	/* If it's deflate, and it's got no preset dictionary, then
	250	we can tell zlib to skip the adler32 check. */
	251	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	252	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	253	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	254
	255	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	256	workspace->strm.next_in += 2;
78809913 SS	257	workspace->strm.avail_in -= 2;
c8b97818 CM	258	}
c8b97818 CM	259
78809913	260	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	261	pr_warn("BTRFS: inflateInit failed\n");
d1111a75	262	kunmap(pages_in[page_in_index]);
60e1975a	263	return -EIO;
c8b97818	264	}
78809913 SS	265	while (workspace->strm.total_in < srclen) {
78809913 SS	266	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	267	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	268	break;
c8b97818	269
3a39c18d	270	buf_start = total_out;
78809913	271	total_out = workspace->strm.total_out;
c8b97818	272
3a39c18d LZ	273	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	274	if (buf_start == total_out)
c8b97818	275	break;
c8b97818	276
3a39c18d LZ	277	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
3a39c18d LZ	278	total_out, disk_start,
974b1adc	279	orig_bio);
3a39c18d LZ	280	if (ret2 == 0) {
	281	ret = 0;
	282	goto done;
c8b97818	283	}
3a39c18d	284
78809913	285	workspace->strm.next_out = workspace->buf;
09cbfeaf	286	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	287
78809913	288	if (workspace->strm.avail_in == 0) {
c8b97818 CM	289	unsigned long tmp;
	290	kunmap(pages_in[page_in_index]);
	291	page_in_index++;
	292	if (page_in_index >= total_pages_in) {
	293	data_in = NULL;
	294	break;
	295	}
	296	data_in = kmap(pages_in[page_in_index]);
78809913 SS	297	workspace->strm.next_in = data_in;
	298	tmp = srclen - workspace->strm.total_in;
	299	workspace->strm.avail_in = min(tmp,
09cbfeaf	300	PAGE_SIZE);
c8b97818 CM	301	}
c8b97818 CM	302	}
d397712b	303	if (ret != Z_STREAM_END)
60e1975a	304	ret = -EIO;
d397712b	305	else
c8b97818	306	ret = 0;
c8b97818	307	done:
78809913	308	zlib_inflateEnd(&workspace->strm);
c8b97818 CM	309	if (data_in)
c8b97818 CM	310	kunmap(pages_in[page_in_index]);
2f19cad9	311	if (!ret)
974b1adc	312	zero_fill_bio(orig_bio);
c8b97818 CM	313	return ret;
	314	}
	315
261507a0 LZ	316	static int zlib_decompress(struct list_head ws, unsigned char data_in,
	317	struct page *dest_page,
	318	unsigned long start_byte,
	319	size_t srclen, size_t destlen)
c8b97818	320	{
261507a0	321	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	322	int ret = 0;
c8b97818 CM	323	int wbits = MAX_WBITS;
2f19cad9	324	unsigned long bytes_left;
c8b97818	325	unsigned long total_out = 0;
2f19cad9	326	unsigned long pg_offset = 0;
c8b97818 CM	327	char *kaddr;
c8b97818 CM	328
2f19cad9 CM	329	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	330	bytes_left = destlen;
	331
78809913 SS	332	workspace->strm.next_in = data_in;
	333	workspace->strm.avail_in = srclen;
	334	workspace->strm.total_in = 0;
c8b97818	335
78809913	336	workspace->strm.next_out = workspace->buf;
09cbfeaf	337	workspace->strm.avail_out = PAGE_SIZE;
78809913	338	workspace->strm.total_out = 0;
c8b97818 CM	339	/* If it's deflate, and it's got no preset dictionary, then
	340	we can tell zlib to skip the adler32 check. */
	341	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	342	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	343	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	344
	345	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	346	workspace->strm.next_in += 2;
78809913 SS	347	workspace->strm.avail_in -= 2;
c8b97818 CM	348	}
c8b97818 CM	349
78809913	350	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	351	pr_warn("BTRFS: inflateInit failed\n");
60e1975a	352	return -EIO;
c8b97818 CM	353	}
c8b97818 CM	354
d397712b	355	while (bytes_left > 0) {
c8b97818 CM	356	unsigned long buf_start;
	357	unsigned long buf_offset;
	358	unsigned long bytes;
c8b97818	359
78809913	360	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	361	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	362	break;
c8b97818 CM	363
c8b97818 CM	364	buf_start = total_out;
78809913	365	total_out = workspace->strm.total_out;
c8b97818 CM	366
c8b97818 CM	367	if (total_out == buf_start) {
60e1975a	368	ret = -EIO;
c8b97818 CM	369	break;
	370	}
	371
d397712b	372	if (total_out <= start_byte)
c8b97818	373	goto next;
c8b97818	374
d397712b	375	if (total_out > start_byte && buf_start < start_byte)
c8b97818	376	buf_offset = start_byte - buf_start;
d397712b	377	else
c8b97818	378	buf_offset = 0;
c8b97818	379
09cbfeaf KS	380	bytes = min(PAGE_SIZE - pg_offset,
09cbfeaf KS	381	PAGE_SIZE - buf_offset);
c8b97818 CM	382	bytes = min(bytes, bytes_left);
c8b97818 CM	383
7ac687d9	384	kaddr = kmap_atomic(dest_page);
c8b97818	385	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
7ac687d9	386	kunmap_atomic(kaddr);
c8b97818 CM	387
	388	pg_offset += bytes;
	389	bytes_left -= bytes;
	390	next:
78809913	391	workspace->strm.next_out = workspace->buf;
09cbfeaf	392	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	393	}
d397712b CM	394
d397712b CM	395	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	396	ret = -EIO;
d397712b	397	else
c8b97818	398	ret = 0;
d397712b	399
78809913	400	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	401
	402	/*
	403	* this should only happen if zlib returned fewer bytes than we
	404	* expected. btrfs_get_block is responsible for zeroing from the
	405	* end of the inline extent (destlen) to the end of the page
	406	*/
	407	if (pg_offset < destlen) {
	408	kaddr = kmap_atomic(dest_page);
	409	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	410	kunmap_atomic(kaddr);
	411	}
c8b97818 CM	412	return ret;
	413	}
	414
f51d2b59 DS	415	static void zlib_set_level(struct list_head *ws, unsigned int type)
	416	{
	417	struct workspace *workspace = list_entry(ws, struct workspace, list);
1972708a	418	unsigned int level = btrfs_compress_level(type);
f51d2b59 DS	419
	420	if (level > 9)
	421	level = 9;
	422
	423	workspace->level = level > 0 ? level : 3;
	424	}
	425
e8c9f186	426	const struct btrfs_compress_op btrfs_zlib_compress = {
92ee5530 DZ	427	.init_workspace_manager = zlib_init_workspace_manager,
	428	.cleanup_workspace_manager = zlib_cleanup_workspace_manager,
	429	.get_workspace = zlib_get_workspace,
	430	.put_workspace = zlib_put_workspace,
261507a0 LZ	431	.alloc_workspace = zlib_alloc_workspace,
	432	.free_workspace = zlib_free_workspace,
	433	.compress_pages = zlib_compress_pages,
974b1adc	434	.decompress_bio = zlib_decompress_bio,
261507a0	435	.decompress = zlib_decompress,
f51d2b59	436	.set_level = zlib_set_level,
261507a0	437	};