[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"

/* workspace buffer size for s390 zlib hardware support */
#define ZLIB_DFLTCC_BUF_SIZE    (4 * PAGE_SIZE)

struct workspace {
	z_stream strm;
	char *buf;
	unsigned int buf_size;
	struct list_head list;
	int level;
};

static struct workspace_manager wsm;

struct list_head *zlib_get_workspace(unsigned int level)
{
	struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
	struct workspace *workspace = list_entry(ws, struct workspace, list);

	workspace->level = level;

	return ws;
}

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);
}

struct list_head *zlib_alloc_workspace(unsigned int level)
{
	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 = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN);
	workspace->level = level;
	workspace->buf = NULL;
	/*
	 * In case of s390 zlib hardware support, allocate lager workspace
	 * buffer. If allocator fails, fall back to a single page buffer.
	 */
	if (zlib_deflate_dfltcc_enabled()) {
		workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
					 __GFP_NOMEMALLOC | __GFP_NORETRY |
					 __GFP_NOWARN | GFP_NOIO);
		workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
	}
	if (!workspace->buf) {
		workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
		workspace->buf_size = PAGE_SIZE;
	}
	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);
}

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 = NULL;
	char *cpage_out;
	int nr_pages = 0;
	struct page *in_page = NULL;
	struct page *out_page = NULL;
	unsigned long bytes_left;
	unsigned int in_buf_pages;
	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;

	out_page = btrfs_alloc_compr_page();
	if (out_page == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	cpage_out = page_address(out_page);
	pages[0] = out_page;
	nr_pages = 1;

	workspace->strm.next_in = workspace->buf;
	workspace->strm.avail_in = 0;
	workspace->strm.next_out = cpage_out;
	workspace->strm.avail_out = PAGE_SIZE;

	while (workspace->strm.total_in < len) {
		/*
		 * Get next input pages and copy the contents to
		 * the workspace buffer if required.
		 */
		if (workspace->strm.avail_in == 0) {
			bytes_left = len - workspace->strm.total_in;
			in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
					   workspace->buf_size / PAGE_SIZE);
			if (in_buf_pages > 1) {
				int i;

				for (i = 0; i < in_buf_pages; i++) {
					if (data_in) {
						kunmap_local(data_in);
						put_page(in_page);
					}
					in_page = find_get_page(mapping,
								start >> PAGE_SHIFT);
					data_in = kmap_local_page(in_page);
					copy_page(workspace->buf + i * PAGE_SIZE,
						  data_in);
					start += PAGE_SIZE;
				}
				workspace->strm.next_in = workspace->buf;
			} else {
				if (data_in) {
					kunmap_local(data_in);
					put_page(in_page);
				}
				in_page = find_get_page(mapping,
							start >> PAGE_SHIFT);
				data_in = kmap_local_page(in_page);
				start += PAGE_SIZE;
				workspace->strm.next_in = data_in;
			}
			workspace->strm.avail_in = min(bytes_left,
						       (unsigned long) workspace->buf_size);
		}

		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) {
			if (nr_pages == nr_dest_pages) {
				ret = -E2BIG;
				goto out;
			}
			out_page = btrfs_alloc_compr_page();
			if (out_page == NULL) {
				ret = -ENOMEM;
				goto out;
			}
			cpage_out = page_address(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;
		if (workspace->strm.total_out > max_out)
			break;
	}
	workspace->strm.avail_in = 0;
	/*
	 * Call deflate with Z_FINISH flush parameter providing more output
	 * space but no more input data, until it returns with Z_STREAM_END.
	 */
	while (ret != Z_STREAM_END) {
		ret = zlib_deflate(&workspace->strm, Z_FINISH);
		if (ret == Z_STREAM_END)
			break;
		if (ret != Z_OK && ret != Z_BUF_ERROR) {
			zlib_deflateEnd(&workspace->strm);
			ret = -EIO;
			goto out;
		} else if (workspace->strm.avail_out == 0) {
			/* get another page for the stream end */
			if (nr_pages == nr_dest_pages) {
				ret = -E2BIG;
				goto out;
			}
			out_page = btrfs_alloc_compr_page();
			if (out_page == NULL) {
				ret = -ENOMEM;
				goto out;
			}
			cpage_out = page_address(out_page);
			pages[nr_pages] = out_page;
			nr_pages++;
			workspace->strm.avail_out = PAGE_SIZE;
			workspace->strm.next_out = cpage_out;
		}
	}
	zlib_deflateEnd(&workspace->strm);

	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 (data_in) {
		kunmap_local(data_in);
		put_page(in_page);
	}

	return ret;
}

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;

	data_in = kmap_local_page(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 = workspace->buf_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_local(data_in);
		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,
				total_out - buf_start, cb, buf_start);
		if (ret2 == 0) {
			ret = 0;
			goto done;
		}

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

		if (workspace->strm.avail_in == 0) {
			unsigned long tmp;
			kunmap_local(data_in);
			page_in_index++;
			if (page_in_index >= total_pages_in) {
				data_in = NULL;
				break;
			}
			data_in = kmap_local_page(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_local(data_in);
	return ret;
}

int zlib_decompress(struct list_head *ws, const u8 *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;

	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 = workspace->buf_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 % PAGE_SIZE));
		bytes = min(bytes, bytes_left);

		memcpy_to_page(dest_page, pg_offset,
			       workspace->buf + buf_offset, bytes);

		pg_offset += bytes;
		bytes_left -= bytes;
next:
		workspace->strm.next_out = workspace->buf;
		workspace->strm.avail_out = workspace->buf_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) {
		memzero_page(dest_page, pg_offset, destlen - pg_offset);
	}
	return ret;
}

const struct btrfs_compress_op btrfs_zlib_compress = {
	.workspace_manager	= &wsm,
	.max_level		= 9,
	.default_level		= BTRFS_ZLIB_DEFAULT_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
3fd396af MZ	23	/* workspace buffer size for s390 zlib hardware support */
	24	#define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
	25
c8b97818	26	struct workspace {
78809913	27	z_stream strm;
c8b97818	28	char *buf;
3fd396af	29	unsigned int buf_size;
c8b97818	30	struct list_head list;
f51d2b59	31	int level;
c8b97818 CM	32	};
c8b97818 CM	33
92ee5530 DZ	34	static struct workspace_manager wsm;
92ee5530 DZ	35
d20f395f	36	struct list_head *zlib_get_workspace(unsigned int level)
92ee5530	37	{
5907a9bb	38	struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
d0ab62ce DZ	39	struct workspace *workspace = list_entry(ws, struct workspace, list);
	40
	41	workspace->level = level;
	42
	43	return ws;
92ee5530 DZ	44	}
92ee5530 DZ	45
d20f395f	46	void zlib_free_workspace(struct list_head *ws)
261507a0 LZ	47	{
261507a0 LZ	48	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	49
6acafd1e	50	kvfree(workspace->strm.workspace);
261507a0 LZ	51	kfree(workspace->buf);
	52	kfree(workspace);
	53	}
	54
d20f395f	55	struct list_head *zlib_alloc_workspace(unsigned int level)
c8b97818 CM	56	{
c8b97818 CM	57	struct workspace *workspace;
78809913	58	int workspacesize;
8844355d	59
389a6cfc	60	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
261507a0 LZ	61	if (!workspace)
261507a0 LZ	62	return ERR_PTR(-ENOMEM);
c8b97818	63
78809913 SS	64	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
78809913 SS	65	zlib_inflate_workspacesize());
8ab546bb	66	workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL \| __GFP_NOWARN);
7bf49943	67	workspace->level = level;
3fd396af MZ	68	workspace->buf = NULL;
	69	/*
	70	* In case of s390 zlib hardware support, allocate lager workspace
	71	* buffer. If allocator fails, fall back to a single page buffer.
	72	*/
	73	if (zlib_deflate_dfltcc_enabled()) {
	74	workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
	75	__GFP_NOMEMALLOC \| __GFP_NORETRY \|
	76	__GFP_NOWARN \| GFP_NOIO);
	77	workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
	78	}
	79	if (!workspace->buf) {
	80	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	81	workspace->buf_size = PAGE_SIZE;
	82	}
78809913	83	if (!workspace->strm.workspace \|\| !workspace->buf)
261507a0	84	goto fail;
c8b97818	85
261507a0	86	INIT_LIST_HEAD(&workspace->list);
c8b97818	87
261507a0 LZ	88	return &workspace->list;
	89	fail:
	90	zlib_free_workspace(&workspace->list);
	91	return ERR_PTR(-ENOMEM);
c8b97818 CM	92	}
c8b97818 CM	93
c4bf665a DS	94	int zlib_compress_pages(struct list_head ws, struct address_space mapping,
	95	u64 start, struct page *pages, unsigned long out_pages,
	96	unsigned long total_in, unsigned long total_out)
c8b97818	97	{
261507a0	98	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	99	int ret;
718e5855	100	char *data_in = NULL;
c8b97818 CM	101	char *cpage_out;
	102	int nr_pages = 0;
	103	struct page *in_page = NULL;
	104	struct page *out_page = NULL;
c8b97818	105	unsigned long bytes_left;
3fd396af	106	unsigned int in_buf_pages;
38c31464	107	unsigned long len = *total_out;
4d3a800e	108	unsigned long nr_dest_pages = *out_pages;
e5d74902	109	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
c8b97818 CM	110
	111	*out_pages = 0;
	112	*total_out = 0;
	113	*total_in = 0;
	114
f51d2b59	115	if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
62e85577	116	pr_warn("BTRFS: deflateInit failed\n");
60e1975a	117	ret = -EIO;
c8b97818 CM	118	goto out;
	119	}
	120
78809913 SS	121	workspace->strm.total_in = 0;
78809913 SS	122	workspace->strm.total_out = 0;
c8b97818	123
9ba965dc	124	out_page = btrfs_alloc_compr_page();
4b72029d	125	if (out_page == NULL) {
60e1975a	126	ret = -ENOMEM;
4b72029d LZ	127	goto out;
4b72029d LZ	128	}
718e5855	129	cpage_out = page_address(out_page);
c8b97818 CM	130	pages[0] = out_page;
	131	nr_pages = 1;
	132
3fd396af MZ	133	workspace->strm.next_in = workspace->buf;
3fd396af MZ	134	workspace->strm.avail_in = 0;
78809913	135	workspace->strm.next_out = cpage_out;
09cbfeaf	136	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	137
78809913	138	while (workspace->strm.total_in < len) {
3fd396af MZ	139	/*
	140	* Get next input pages and copy the contents to
	141	* the workspace buffer if required.
	142	*/
	143	if (workspace->strm.avail_in == 0) {
	144	bytes_left = len - workspace->strm.total_in;
	145	in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
	146	workspace->buf_size / PAGE_SIZE);
	147	if (in_buf_pages > 1) {
	148	int i;
	149
	150	for (i = 0; i < in_buf_pages; i++) {
718e5855 FDF	151	if (data_in) {
718e5855 FDF	152	kunmap_local(data_in);
3fd396af	153	put_page(in_page);
55276e14	154	}
3fd396af MZ	155	in_page = find_get_page(mapping,
3fd396af MZ	156	start >> PAGE_SHIFT);
718e5855	157	data_in = kmap_local_page(in_page);
9e5e6d4e DS	158	copy_page(workspace->buf + i * PAGE_SIZE,
9e5e6d4e DS	159	data_in);
3fd396af MZ	160	start += PAGE_SIZE;
	161	}
	162	workspace->strm.next_in = workspace->buf;
	163	} else {
718e5855 FDF	164	if (data_in) {
718e5855 FDF	165	kunmap_local(data_in);
3fd396af	166	put_page(in_page);
55276e14	167	}
3fd396af MZ	168	in_page = find_get_page(mapping,
3fd396af MZ	169	start >> PAGE_SHIFT);
718e5855	170	data_in = kmap_local_page(in_page);
3fd396af MZ	171	start += PAGE_SIZE;
	172	workspace->strm.next_in = data_in;
	173	}
	174	workspace->strm.avail_in = min(bytes_left,
	175	(unsigned long) workspace->buf_size);
	176	}
	177
78809913	178	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	179	if (ret != Z_OK) {
62e85577	180	pr_debug("BTRFS: deflate in loop returned %d\n",
c8b97818	181	ret);
78809913	182	zlib_deflateEnd(&workspace->strm);
60e1975a	183	ret = -EIO;
c8b97818 CM	184	goto out;
	185	}
	186
	187	/* we're making it bigger, give up */
78809913 SS	188	if (workspace->strm.total_in > 8192 &&
	189	workspace->strm.total_in <
	190	workspace->strm.total_out) {
130d5b41	191	ret = -E2BIG;
c8b97818 CM	192	goto out;
	193	}
	194	/* we need another page for writing out. Test this
	195	* before the total_in so we will pull in a new page for
	196	* the stream end if required
	197	*/
78809913	198	if (workspace->strm.avail_out == 0) {
c8b97818	199	if (nr_pages == nr_dest_pages) {
60e1975a	200	ret = -E2BIG;
c8b97818 CM	201	goto out;
c8b97818 CM	202	}
9ba965dc	203	out_page = btrfs_alloc_compr_page();
4b72029d	204	if (out_page == NULL) {
60e1975a	205	ret = -ENOMEM;
4b72029d LZ	206	goto out;
4b72029d LZ	207	}
718e5855	208	cpage_out = page_address(out_page);
c8b97818 CM	209	pages[nr_pages] = out_page;
c8b97818 CM	210	nr_pages++;
09cbfeaf	211	workspace->strm.avail_out = PAGE_SIZE;
78809913	212	workspace->strm.next_out = cpage_out;
c8b97818 CM	213	}
c8b97818 CM	214	/* we're all done */
78809913	215	if (workspace->strm.total_in >= len)
c8b97818	216	break;
3fd396af MZ	217	if (workspace->strm.total_out > max_out)
3fd396af MZ	218	break;
c8b97818	219	}
78809913	220	workspace->strm.avail_in = 0;
3fd396af MZ	221	/*
	222	* Call deflate with Z_FINISH flush parameter providing more output
	223	* space but no more input data, until it returns with Z_STREAM_END.
	224	*/
	225	while (ret != Z_STREAM_END) {
	226	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	227	if (ret == Z_STREAM_END)
	228	break;
	229	if (ret != Z_OK && ret != Z_BUF_ERROR) {
	230	zlib_deflateEnd(&workspace->strm);
	231	ret = -EIO;
	232	goto out;
	233	} else if (workspace->strm.avail_out == 0) {
	234	/* get another page for the stream end */
3fd396af	235	if (nr_pages == nr_dest_pages) {
3fd396af MZ	236	ret = -E2BIG;
	237	goto out;
	238	}
9ba965dc	239	out_page = btrfs_alloc_compr_page();
3fd396af MZ	240	if (out_page == NULL) {
	241	ret = -ENOMEM;
	242	goto out;
	243	}
718e5855	244	cpage_out = page_address(out_page);
3fd396af MZ	245	pages[nr_pages] = out_page;
	246	nr_pages++;
	247	workspace->strm.avail_out = PAGE_SIZE;
	248	workspace->strm.next_out = cpage_out;
	249	}
c8b97818	250	}
3fd396af	251	zlib_deflateEnd(&workspace->strm);
c8b97818	252
78809913	253	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	254	ret = -E2BIG;
c8b97818 CM	255	goto out;
	256	}
	257
	258	ret = 0;
78809913 SS	259	*total_out = workspace->strm.total_out;
78809913 SS	260	*total_in = workspace->strm.total_in;
c8b97818 CM	261	out:
c8b97818 CM	262	*out_pages = nr_pages;
718e5855 FDF	263	if (data_in) {
718e5855 FDF	264	kunmap_local(data_in);
09cbfeaf	265	put_page(in_page);
55276e14	266	}
718e5855	267
c8b97818 CM	268	return ret;
	269	}
	270
c4bf665a	271	int zlib_decompress_bio(struct list_head ws, struct compressed_bio cb)
c8b97818	272	{
261507a0	273	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	274	int ret = 0, ret2;
c8b97818	275	int wbits = MAX_WBITS;
c8b97818 CM	276	char *data_in;
c8b97818 CM	277	size_t total_out = 0;
c8b97818	278	unsigned long page_in_index = 0;
e1ddce71	279	size_t srclen = cb->compressed_len;
09cbfeaf	280	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	281	unsigned long buf_start;
e1ddce71	282	struct page **pages_in = cb->compressed_pages;
c8b97818	283
5a6e6e7c	284	data_in = kmap_local_page(pages_in[page_in_index]);
78809913	285	workspace->strm.next_in = data_in;
09cbfeaf	286	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
78809913	287	workspace->strm.total_in = 0;
c8b97818	288
78809913 SS	289	workspace->strm.total_out = 0;
78809913 SS	290	workspace->strm.next_out = workspace->buf;
3fd396af	291	workspace->strm.avail_out = workspace->buf_size;
c8b97818 CM	292
	293	/* If it's deflate, and it's got no preset dictionary, then
	294	we can tell zlib to skip the adler32 check. */
	295	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	296	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	297	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	298
	299	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	300	workspace->strm.next_in += 2;
78809913 SS	301	workspace->strm.avail_in -= 2;
c8b97818 CM	302	}
c8b97818 CM	303
78809913	304	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	305	pr_warn("BTRFS: inflateInit failed\n");
5a6e6e7c	306	kunmap_local(data_in);
60e1975a	307	return -EIO;
c8b97818	308	}
78809913 SS	309	while (workspace->strm.total_in < srclen) {
78809913 SS	310	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	311	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	312	break;
c8b97818	313
3a39c18d	314	buf_start = total_out;
78809913	315	total_out = workspace->strm.total_out;
c8b97818	316
3a39c18d LZ	317	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	318	if (buf_start == total_out)
c8b97818	319	break;
c8b97818	320
1c3dc173 QW	321	ret2 = btrfs_decompress_buf2page(workspace->buf,
1c3dc173 QW	322	total_out - buf_start, cb, buf_start);
3a39c18d LZ	323	if (ret2 == 0) {
	324	ret = 0;
	325	goto done;
c8b97818	326	}
3a39c18d	327
78809913	328	workspace->strm.next_out = workspace->buf;
3fd396af	329	workspace->strm.avail_out = workspace->buf_size;
c8b97818	330
78809913	331	if (workspace->strm.avail_in == 0) {
c8b97818	332	unsigned long tmp;
5a6e6e7c	333	kunmap_local(data_in);
c8b97818 CM	334	page_in_index++;
	335	if (page_in_index >= total_pages_in) {
	336	data_in = NULL;
	337	break;
	338	}
5a6e6e7c	339	data_in = kmap_local_page(pages_in[page_in_index]);
78809913 SS	340	workspace->strm.next_in = data_in;
78809913 SS	341	tmp = srclen - workspace->strm.total_in;
1c3dc173	342	workspace->strm.avail_in = min(tmp, PAGE_SIZE);
c8b97818 CM	343	}
c8b97818 CM	344	}
d397712b	345	if (ret != Z_STREAM_END)
60e1975a	346	ret = -EIO;
d397712b	347	else
c8b97818	348	ret = 0;
c8b97818	349	done:
78809913	350	zlib_inflateEnd(&workspace->strm);
55276e14	351	if (data_in)
5a6e6e7c	352	kunmap_local(data_in);
c8b97818 CM	353	return ret;
	354	}
	355
3e09b5b2	356	int zlib_decompress(struct list_head ws, const u8 data_in,
c4bf665a DS	357	struct page *dest_page, unsigned long start_byte, size_t srclen,
c4bf665a DS	358	size_t destlen)
c8b97818	359	{
261507a0	360	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	361	int ret = 0;
c8b97818 CM	362	int wbits = MAX_WBITS;
2f19cad9	363	unsigned long bytes_left;
c8b97818	364	unsigned long total_out = 0;
2f19cad9	365	unsigned long pg_offset = 0;
c8b97818	366
2f19cad9 CM	367	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	368	bytes_left = destlen;
	369
78809913 SS	370	workspace->strm.next_in = data_in;
	371	workspace->strm.avail_in = srclen;
	372	workspace->strm.total_in = 0;
c8b97818	373
78809913	374	workspace->strm.next_out = workspace->buf;
3fd396af	375	workspace->strm.avail_out = workspace->buf_size;
78809913	376	workspace->strm.total_out = 0;
c8b97818 CM	377	/* If it's deflate, and it's got no preset dictionary, then
	378	we can tell zlib to skip the adler32 check. */
	379	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	380	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	381	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	382
	383	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	384	workspace->strm.next_in += 2;
78809913 SS	385	workspace->strm.avail_in -= 2;
c8b97818 CM	386	}
c8b97818 CM	387
78809913	388	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	389	pr_warn("BTRFS: inflateInit failed\n");
60e1975a	390	return -EIO;
c8b97818 CM	391	}
c8b97818 CM	392
d397712b	393	while (bytes_left > 0) {
c8b97818 CM	394	unsigned long buf_start;
	395	unsigned long buf_offset;
	396	unsigned long bytes;
c8b97818	397
78809913	398	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	399	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	400	break;
c8b97818 CM	401
c8b97818 CM	402	buf_start = total_out;
78809913	403	total_out = workspace->strm.total_out;
c8b97818 CM	404
c8b97818 CM	405	if (total_out == buf_start) {
60e1975a	406	ret = -EIO;
c8b97818 CM	407	break;
	408	}
	409
d397712b	410	if (total_out <= start_byte)
c8b97818	411	goto next;
c8b97818	412
d397712b	413	if (total_out > start_byte && buf_start < start_byte)
c8b97818	414	buf_offset = start_byte - buf_start;
d397712b	415	else
c8b97818	416	buf_offset = 0;
c8b97818	417
09cbfeaf	418	bytes = min(PAGE_SIZE - pg_offset,
3fd396af	419	PAGE_SIZE - (buf_offset % PAGE_SIZE));
c8b97818 CM	420	bytes = min(bytes, bytes_left);
c8b97818 CM	421
3590ec58 IW	422	memcpy_to_page(dest_page, pg_offset,
3590ec58 IW	423	workspace->buf + buf_offset, bytes);
c8b97818 CM	424
	425	pg_offset += bytes;
	426	bytes_left -= bytes;
	427	next:
78809913	428	workspace->strm.next_out = workspace->buf;
3fd396af	429	workspace->strm.avail_out = workspace->buf_size;
c8b97818	430	}
d397712b CM	431
d397712b CM	432	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	433	ret = -EIO;
d397712b	434	else
c8b97818	435	ret = 0;
d397712b	436
78809913	437	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	438
	439	/*
	440	* this should only happen if zlib returned fewer bytes than we
	441	* expected. btrfs_get_block is responsible for zeroing from the
	442	* end of the inline extent (destlen) to the end of the page
	443	*/
	444	if (pg_offset < destlen) {
d048b9c2	445	memzero_page(dest_page, pg_offset, destlen - pg_offset);
2f19cad9	446	}
c8b97818 CM	447	return ret;
	448	}
	449
e8c9f186	450	const struct btrfs_compress_op btrfs_zlib_compress = {
be951045	451	.workspace_manager = &wsm,
e18333a7 DS	452	.max_level = 9,
e18333a7 DS	453	.default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
261507a0	454	};