[mirror_ubuntu-jammy-kernel.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(unsigned int level)
{
	struct list_head *ws = btrfs_get_workspace(&wsm, level);
	struct workspace *workspace = list_entry(ws, struct workspace, list);

	workspace->level = level;

	return ws;
}

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(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 = kvmalloc(workspacesize, GFP_KERNEL);
	workspace->level = level;
	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 unsigned int zlib_set_level(unsigned int level)
{
	if (!level)
		return BTRFS_ZLIB_DEFAULT_LEVEL;

	return min_t(unsigned int, level, 9);
}

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
7bf49943	42	static struct list_head *zlib_get_workspace(unsigned int level)
92ee5530	43	{
d0ab62ce DZ	44	struct list_head *ws = btrfs_get_workspace(&wsm, level);
	45	struct workspace *workspace = list_entry(ws, struct workspace, list);
	46
	47	workspace->level = level;
	48
	49	return ws;
92ee5530 DZ	50	}
	51
	52	static void zlib_put_workspace(struct list_head *ws)
	53	{
	54	btrfs_put_workspace(&wsm, ws);
	55	}
	56
261507a0 LZ	57	static void zlib_free_workspace(struct list_head *ws)
	58	{
	59	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	60
6acafd1e	61	kvfree(workspace->strm.workspace);
261507a0 LZ	62	kfree(workspace->buf);
	63	kfree(workspace);
	64	}
	65
7bf49943	66	static struct list_head *zlib_alloc_workspace(unsigned int level)
c8b97818 CM	67	{
c8b97818 CM	68	struct workspace *workspace;
78809913	69	int workspacesize;
8844355d	70
389a6cfc	71	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
261507a0 LZ	72	if (!workspace)
261507a0 LZ	73	return ERR_PTR(-ENOMEM);
c8b97818	74
78809913 SS	75	workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
78809913 SS	76	zlib_inflate_workspacesize());
6acafd1e	77	workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL);
7bf49943	78	workspace->level = level;
389a6cfc	79	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
78809913	80	if (!workspace->strm.workspace \|\| !workspace->buf)
261507a0	81	goto fail;
c8b97818	82
261507a0	83	INIT_LIST_HEAD(&workspace->list);
c8b97818	84
261507a0 LZ	85	return &workspace->list;
	86	fail:
	87	zlib_free_workspace(&workspace->list);
	88	return ERR_PTR(-ENOMEM);
c8b97818 CM	89	}
c8b97818 CM	90
261507a0 LZ	91	static int zlib_compress_pages(struct list_head *ws,
261507a0 LZ	92	struct address_space *mapping,
38c31464	93	u64 start,
261507a0	94	struct page **pages,
261507a0 LZ	95	unsigned long *out_pages,
261507a0 LZ	96	unsigned long *total_in,
e5d74902	97	unsigned long *total_out)
c8b97818	98	{
261507a0	99	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818	100	int ret;
c8b97818 CM	101	char *data_in;
	102	char *cpage_out;
	103	int nr_pages = 0;
	104	struct page *in_page = NULL;
	105	struct page *out_page = NULL;
c8b97818	106	unsigned long bytes_left;
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
09cbfeaf	124	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
c8b97818 CM	125	data_in = kmap(in_page);
	126
	127	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	128	if (out_page == NULL) {
60e1975a	129	ret = -ENOMEM;
4b72029d LZ	130	goto out;
4b72029d LZ	131	}
c8b97818 CM	132	cpage_out = kmap(out_page);
	133	pages[0] = out_page;
	134	nr_pages = 1;
	135
78809913 SS	136	workspace->strm.next_in = data_in;
78809913 SS	137	workspace->strm.next_out = cpage_out;
09cbfeaf KS	138	workspace->strm.avail_out = PAGE_SIZE;
09cbfeaf KS	139	workspace->strm.avail_in = min(len, PAGE_SIZE);
c8b97818	140
78809913 SS	141	while (workspace->strm.total_in < len) {
78809913 SS	142	ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
c8b97818	143	if (ret != Z_OK) {
62e85577	144	pr_debug("BTRFS: deflate in loop returned %d\n",
c8b97818	145	ret);
78809913	146	zlib_deflateEnd(&workspace->strm);
60e1975a	147	ret = -EIO;
c8b97818 CM	148	goto out;
	149	}
	150
	151	/* we're making it bigger, give up */
78809913 SS	152	if (workspace->strm.total_in > 8192 &&
	153	workspace->strm.total_in <
	154	workspace->strm.total_out) {
130d5b41	155	ret = -E2BIG;
c8b97818 CM	156	goto out;
	157	}
	158	/* we need another page for writing out. Test this
	159	* before the total_in so we will pull in a new page for
	160	* the stream end if required
	161	*/
78809913	162	if (workspace->strm.avail_out == 0) {
c8b97818 CM	163	kunmap(out_page);
	164	if (nr_pages == nr_dest_pages) {
	165	out_page = NULL;
60e1975a	166	ret = -E2BIG;
c8b97818 CM	167	goto out;
	168	}
	169	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
4b72029d	170	if (out_page == NULL) {
60e1975a	171	ret = -ENOMEM;
4b72029d LZ	172	goto out;
4b72029d LZ	173	}
c8b97818 CM	174	cpage_out = kmap(out_page);
	175	pages[nr_pages] = out_page;
	176	nr_pages++;
09cbfeaf	177	workspace->strm.avail_out = PAGE_SIZE;
78809913	178	workspace->strm.next_out = cpage_out;
c8b97818 CM	179	}
c8b97818 CM	180	/* we're all done */
78809913	181	if (workspace->strm.total_in >= len)
c8b97818 CM	182	break;
	183
	184	/* we've read in a full page, get a new one */
78809913 SS	185	if (workspace->strm.avail_in == 0) {
78809913 SS	186	if (workspace->strm.total_out > max_out)
c8b97818 CM	187	break;
c8b97818 CM	188
78809913	189	bytes_left = len - workspace->strm.total_in;
c8b97818	190	kunmap(in_page);
09cbfeaf	191	put_page(in_page);
c8b97818	192
09cbfeaf	193	start += PAGE_SIZE;
c8b97818	194	in_page = find_get_page(mapping,
09cbfeaf	195	start >> PAGE_SHIFT);
c8b97818	196	data_in = kmap(in_page);
78809913	197	workspace->strm.avail_in = min(bytes_left,
09cbfeaf	198	PAGE_SIZE);
78809913	199	workspace->strm.next_in = data_in;
c8b97818 CM	200	}
c8b97818 CM	201	}
78809913 SS	202	workspace->strm.avail_in = 0;
	203	ret = zlib_deflate(&workspace->strm, Z_FINISH);
	204	zlib_deflateEnd(&workspace->strm);
c8b97818 CM	205
c8b97818 CM	206	if (ret != Z_STREAM_END) {
60e1975a	207	ret = -EIO;
c8b97818 CM	208	goto out;
	209	}
	210
78809913	211	if (workspace->strm.total_out >= workspace->strm.total_in) {
60e1975a	212	ret = -E2BIG;
c8b97818 CM	213	goto out;
	214	}
	215
	216	ret = 0;
78809913 SS	217	*total_out = workspace->strm.total_out;
78809913 SS	218	*total_in = workspace->strm.total_in;
c8b97818 CM	219	out:
	220	*out_pages = nr_pages;
	221	if (out_page)
	222	kunmap(out_page);
	223
	224	if (in_page) {
	225	kunmap(in_page);
09cbfeaf	226	put_page(in_page);
c8b97818	227	}
c8b97818 CM	228	return ret;
	229	}
	230
e1ddce71	231	static int zlib_decompress_bio(struct list_head ws, struct compressed_bio cb)
c8b97818	232	{
261507a0	233	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	234	int ret = 0, ret2;
c8b97818	235	int wbits = MAX_WBITS;
c8b97818 CM	236	char *data_in;
c8b97818 CM	237	size_t total_out = 0;
c8b97818	238	unsigned long page_in_index = 0;
e1ddce71	239	size_t srclen = cb->compressed_len;
09cbfeaf	240	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
c8b97818	241	unsigned long buf_start;
e1ddce71 AJ	242	struct page **pages_in = cb->compressed_pages;
	243	u64 disk_start = cb->start;
	244	struct bio *orig_bio = cb->orig_bio;
c8b97818	245
c8b97818	246	data_in = kmap(pages_in[page_in_index]);
78809913	247	workspace->strm.next_in = data_in;
09cbfeaf	248	workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
78809913	249	workspace->strm.total_in = 0;
c8b97818	250
78809913 SS	251	workspace->strm.total_out = 0;
78809913 SS	252	workspace->strm.next_out = workspace->buf;
09cbfeaf	253	workspace->strm.avail_out = PAGE_SIZE;
c8b97818 CM	254
	255	/* If it's deflate, and it's got no preset dictionary, then
	256	we can tell zlib to skip the adler32 check. */
	257	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	258	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	259	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	260
	261	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	262	workspace->strm.next_in += 2;
78809913 SS	263	workspace->strm.avail_in -= 2;
c8b97818 CM	264	}
c8b97818 CM	265
78809913	266	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	267	pr_warn("BTRFS: inflateInit failed\n");
d1111a75	268	kunmap(pages_in[page_in_index]);
60e1975a	269	return -EIO;
c8b97818	270	}
78809913 SS	271	while (workspace->strm.total_in < srclen) {
78809913 SS	272	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	273	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	274	break;
c8b97818	275
3a39c18d	276	buf_start = total_out;
78809913	277	total_out = workspace->strm.total_out;
c8b97818	278
3a39c18d LZ	279	/* we didn't make progress in this inflate call, we're done */
3a39c18d LZ	280	if (buf_start == total_out)
c8b97818	281	break;
c8b97818	282
3a39c18d LZ	283	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
3a39c18d LZ	284	total_out, disk_start,
974b1adc	285	orig_bio);
3a39c18d LZ	286	if (ret2 == 0) {
	287	ret = 0;
	288	goto done;
c8b97818	289	}
3a39c18d	290
78809913	291	workspace->strm.next_out = workspace->buf;
09cbfeaf	292	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	293
78809913	294	if (workspace->strm.avail_in == 0) {
c8b97818 CM	295	unsigned long tmp;
	296	kunmap(pages_in[page_in_index]);
	297	page_in_index++;
	298	if (page_in_index >= total_pages_in) {
	299	data_in = NULL;
	300	break;
	301	}
	302	data_in = kmap(pages_in[page_in_index]);
78809913 SS	303	workspace->strm.next_in = data_in;
	304	tmp = srclen - workspace->strm.total_in;
	305	workspace->strm.avail_in = min(tmp,
09cbfeaf	306	PAGE_SIZE);
c8b97818 CM	307	}
c8b97818 CM	308	}
d397712b	309	if (ret != Z_STREAM_END)
60e1975a	310	ret = -EIO;
d397712b	311	else
c8b97818	312	ret = 0;
c8b97818	313	done:
78809913	314	zlib_inflateEnd(&workspace->strm);
c8b97818 CM	315	if (data_in)
c8b97818 CM	316	kunmap(pages_in[page_in_index]);
2f19cad9	317	if (!ret)
974b1adc	318	zero_fill_bio(orig_bio);
c8b97818 CM	319	return ret;
	320	}
	321
261507a0 LZ	322	static int zlib_decompress(struct list_head ws, unsigned char data_in,
	323	struct page *dest_page,
	324	unsigned long start_byte,
	325	size_t srclen, size_t destlen)
c8b97818	326	{
261507a0	327	struct workspace *workspace = list_entry(ws, struct workspace, list);
c8b97818 CM	328	int ret = 0;
c8b97818 CM	329	int wbits = MAX_WBITS;
2f19cad9	330	unsigned long bytes_left;
c8b97818	331	unsigned long total_out = 0;
2f19cad9	332	unsigned long pg_offset = 0;
c8b97818 CM	333	char *kaddr;
c8b97818 CM	334
2f19cad9 CM	335	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	336	bytes_left = destlen;
	337
78809913 SS	338	workspace->strm.next_in = data_in;
	339	workspace->strm.avail_in = srclen;
	340	workspace->strm.total_in = 0;
c8b97818	341
78809913	342	workspace->strm.next_out = workspace->buf;
09cbfeaf	343	workspace->strm.avail_out = PAGE_SIZE;
78809913	344	workspace->strm.total_out = 0;
c8b97818 CM	345	/* If it's deflate, and it's got no preset dictionary, then
	346	we can tell zlib to skip the adler32 check. */
	347	if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
	348	((data_in[0] & 0x0f) == Z_DEFLATED) &&
	349	!(((data_in[0]<<8) + data_in[1]) % 31)) {
	350
	351	wbits = -((data_in[0] >> 4) + 8);
78809913 SS	352	workspace->strm.next_in += 2;
78809913 SS	353	workspace->strm.avail_in -= 2;
c8b97818 CM	354	}
c8b97818 CM	355
78809913	356	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
62e85577	357	pr_warn("BTRFS: inflateInit failed\n");
60e1975a	358	return -EIO;
c8b97818 CM	359	}
c8b97818 CM	360
d397712b	361	while (bytes_left > 0) {
c8b97818 CM	362	unsigned long buf_start;
	363	unsigned long buf_offset;
	364	unsigned long bytes;
c8b97818	365
78809913	366	ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
d397712b	367	if (ret != Z_OK && ret != Z_STREAM_END)
c8b97818	368	break;
c8b97818 CM	369
c8b97818 CM	370	buf_start = total_out;
78809913	371	total_out = workspace->strm.total_out;
c8b97818 CM	372
c8b97818 CM	373	if (total_out == buf_start) {
60e1975a	374	ret = -EIO;
c8b97818 CM	375	break;
	376	}
	377
d397712b	378	if (total_out <= start_byte)
c8b97818	379	goto next;
c8b97818	380
d397712b	381	if (total_out > start_byte && buf_start < start_byte)
c8b97818	382	buf_offset = start_byte - buf_start;
d397712b	383	else
c8b97818	384	buf_offset = 0;
c8b97818	385
09cbfeaf KS	386	bytes = min(PAGE_SIZE - pg_offset,
09cbfeaf KS	387	PAGE_SIZE - buf_offset);
c8b97818 CM	388	bytes = min(bytes, bytes_left);
c8b97818 CM	389
7ac687d9	390	kaddr = kmap_atomic(dest_page);
c8b97818	391	memcpy(kaddr + pg_offset, workspace->buf + buf_offset, bytes);
7ac687d9	392	kunmap_atomic(kaddr);
c8b97818 CM	393
	394	pg_offset += bytes;
	395	bytes_left -= bytes;
	396	next:
78809913	397	workspace->strm.next_out = workspace->buf;
09cbfeaf	398	workspace->strm.avail_out = PAGE_SIZE;
c8b97818	399	}
d397712b CM	400
d397712b CM	401	if (ret != Z_STREAM_END && bytes_left != 0)
60e1975a	402	ret = -EIO;
d397712b	403	else
c8b97818	404	ret = 0;
d397712b	405
78809913	406	zlib_inflateEnd(&workspace->strm);
2f19cad9 CM	407
	408	/*
	409	* this should only happen if zlib returned fewer bytes than we
	410	* expected. btrfs_get_block is responsible for zeroing from the
	411	* end of the inline extent (destlen) to the end of the page
	412	*/
	413	if (pg_offset < destlen) {
	414	kaddr = kmap_atomic(dest_page);
	415	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	416	kunmap_atomic(kaddr);
	417	}
c8b97818 CM	418	return ret;
	419	}
	420
d0ab62ce	421	static unsigned int zlib_set_level(unsigned int level)
f51d2b59	422	{
d0ab62ce DZ	423	if (!level)
d0ab62ce DZ	424	return BTRFS_ZLIB_DEFAULT_LEVEL;
f51d2b59	425
d0ab62ce	426	return min_t(unsigned int, level, 9);
f51d2b59 DS	427	}
f51d2b59 DS	428
e8c9f186	429	const struct btrfs_compress_op btrfs_zlib_compress = {
92ee5530 DZ	430	.init_workspace_manager = zlib_init_workspace_manager,
	431	.cleanup_workspace_manager = zlib_cleanup_workspace_manager,
	432	.get_workspace = zlib_get_workspace,
	433	.put_workspace = zlib_put_workspace,
261507a0 LZ	434	.alloc_workspace = zlib_alloc_workspace,
	435	.free_workspace = zlib_free_workspace,
	436	.compress_pages = zlib_compress_pages,
974b1adc	437	.decompress_bio = zlib_decompress_bio,
261507a0	438	.decompress = zlib_decompress,
f51d2b59	439	.set_level = zlib_set_level,
261507a0	440	};