[linux-2.6-block.git] / fs / btrfs / zstd.c

/*
 * Copyright (c) 2016-present, Facebook, Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */
#include <linux/bio.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/refcount.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/zstd.h>
#include "compression.h"

#define ZSTD_BTRFS_MAX_WINDOWLOG 17
#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
#define ZSTD_BTRFS_DEFAULT_LEVEL 3

static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len)
{
	ZSTD_parameters params = ZSTD_getParams(ZSTD_BTRFS_DEFAULT_LEVEL,
						src_len, 0);

	if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG)
		params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG;
	WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT);
	return params;
}

struct workspace {
	void *mem;
	size_t size;
	char *buf;
	struct list_head list;
	ZSTD_inBuffer in_buf;
	ZSTD_outBuffer out_buf;
};

static void zstd_free_workspace(struct list_head *ws)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);

	kvfree(workspace->mem);
	kfree(workspace->buf);
	kfree(workspace);
}

static struct list_head *zstd_alloc_workspace(void)
{
	ZSTD_parameters params =
			zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
	struct workspace *workspace;

	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
	if (!workspace)
		return ERR_PTR(-ENOMEM);

	workspace->size = max_t(size_t,
			ZSTD_CStreamWorkspaceBound(params.cParams),
			ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
	workspace->mem = kvmalloc(workspace->size, GFP_KERNEL);
	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!workspace->mem || !workspace->buf)
		goto fail;

	INIT_LIST_HEAD(&workspace->list);

	return &workspace->list;
fail:
	zstd_free_workspace(&workspace->list);
	return ERR_PTR(-ENOMEM);
}

static int zstd_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);
	ZSTD_CStream *stream;
	int ret = 0;
	int nr_pages = 0;
	struct page *in_page = NULL;  /* The current page to read */
	struct page *out_page = NULL; /* The current page to write to */
	unsigned long tot_in = 0;
	unsigned long tot_out = 0;
	unsigned long len = *total_out;
	const unsigned long nr_dest_pages = *out_pages;
	unsigned long max_out = nr_dest_pages * PAGE_SIZE;
	ZSTD_parameters params = zstd_get_btrfs_parameters(len);

	*out_pages = 0;
	*total_out = 0;
	*total_in = 0;

	/* Initialize the stream */
	stream = ZSTD_initCStream(params, len, workspace->mem,
			workspace->size);
	if (!stream) {
		pr_warn("BTRFS: ZSTD_initCStream failed\n");
		ret = -EIO;
		goto out;
	}

	/* map in the first page of input data */
	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
	workspace->in_buf.src = kmap(in_page);
	workspace->in_buf.pos = 0;
	workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);


	/* Allocate and map in the output buffer */
	out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (out_page == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	pages[nr_pages++] = out_page;
	workspace->out_buf.dst = kmap(out_page);
	workspace->out_buf.pos = 0;
	workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);

	while (1) {
		size_t ret2;

		ret2 = ZSTD_compressStream(stream, &workspace->out_buf,
				&workspace->in_buf);
		if (ZSTD_isError(ret2)) {
			pr_debug("BTRFS: ZSTD_compressStream returned %d\n",
					ZSTD_getErrorCode(ret2));
			ret = -EIO;
			goto out;
		}

		/* Check to see if we are making it bigger */
		if (tot_in + workspace->in_buf.pos > 8192 &&
				tot_in + workspace->in_buf.pos <
				tot_out + workspace->out_buf.pos) {
			ret = -E2BIG;
			goto out;
		}

		/* We've reached the end of our output range */
		if (workspace->out_buf.pos >= max_out) {
			tot_out += workspace->out_buf.pos;
			ret = -E2BIG;
			goto out;
		}

		/* Check if we need more output space */
		if (workspace->out_buf.pos == workspace->out_buf.size) {
			tot_out += PAGE_SIZE;
			max_out -= PAGE_SIZE;
			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;
			}
			pages[nr_pages++] = out_page;
			workspace->out_buf.dst = kmap(out_page);
			workspace->out_buf.pos = 0;
			workspace->out_buf.size = min_t(size_t, max_out,
							PAGE_SIZE);
		}

		/* We've reached the end of the input */
		if (workspace->in_buf.pos >= len) {
			tot_in += workspace->in_buf.pos;
			break;
		}

		/* Check if we need more input */
		if (workspace->in_buf.pos == workspace->in_buf.size) {
			tot_in += PAGE_SIZE;
			kunmap(in_page);
			put_page(in_page);

			start += PAGE_SIZE;
			len -= PAGE_SIZE;
			in_page = find_get_page(mapping, start >> PAGE_SHIFT);
			workspace->in_buf.src = kmap(in_page);
			workspace->in_buf.pos = 0;
			workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
		}
	}
	while (1) {
		size_t ret2;

		ret2 = ZSTD_endStream(stream, &workspace->out_buf);
		if (ZSTD_isError(ret2)) {
			pr_debug("BTRFS: ZSTD_endStream returned %d\n",
					ZSTD_getErrorCode(ret2));
			ret = -EIO;
			goto out;
		}
		if (ret2 == 0) {
			tot_out += workspace->out_buf.pos;
			break;
		}
		if (workspace->out_buf.pos >= max_out) {
			tot_out += workspace->out_buf.pos;
			ret = -E2BIG;
			goto out;
		}

		tot_out += PAGE_SIZE;
		max_out -= PAGE_SIZE;
		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;
		}
		pages[nr_pages++] = out_page;
		workspace->out_buf.dst = kmap(out_page);
		workspace->out_buf.pos = 0;
		workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
	}

	if (tot_out >= tot_in) {
		ret = -E2BIG;
		goto out;
	}

	ret = 0;
	*total_in = tot_in;
	*total_out = tot_out;
out:
	*out_pages = nr_pages;
	/* Cleanup */
	if (in_page) {
		kunmap(in_page);
		put_page(in_page);
	}
	if (out_page)
		kunmap(out_page);
	return ret;
}

static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	struct page **pages_in = cb->compressed_pages;
	u64 disk_start = cb->start;
	struct bio *orig_bio = cb->orig_bio;
	size_t srclen = cb->compressed_len;
	ZSTD_DStream *stream;
	int ret = 0;
	unsigned long page_in_index = 0;
	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
	unsigned long buf_start;
	unsigned long total_out = 0;

	stream = ZSTD_initDStream(
			ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
	if (!stream) {
		pr_debug("BTRFS: ZSTD_initDStream failed\n");
		ret = -EIO;
		goto done;
	}

	workspace->in_buf.src = kmap(pages_in[page_in_index]);
	workspace->in_buf.pos = 0;
	workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);

	workspace->out_buf.dst = workspace->buf;
	workspace->out_buf.pos = 0;
	workspace->out_buf.size = PAGE_SIZE;

	while (1) {
		size_t ret2;

		ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
				&workspace->in_buf);
		if (ZSTD_isError(ret2)) {
			pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
					ZSTD_getErrorCode(ret2));
			ret = -EIO;
			goto done;
		}
		buf_start = total_out;
		total_out += workspace->out_buf.pos;
		workspace->out_buf.pos = 0;

		ret = btrfs_decompress_buf2page(workspace->out_buf.dst,
				buf_start, total_out, disk_start, orig_bio);
		if (ret == 0)
			break;

		if (workspace->in_buf.pos >= srclen)
			break;

		/* Check if we've hit the end of a frame */
		if (ret2 == 0)
			break;

		if (workspace->in_buf.pos == workspace->in_buf.size) {
			kunmap(pages_in[page_in_index++]);
			if (page_in_index >= total_pages_in) {
				workspace->in_buf.src = NULL;
				ret = -EIO;
				goto done;
			}
			srclen -= PAGE_SIZE;
			workspace->in_buf.src = kmap(pages_in[page_in_index]);
			workspace->in_buf.pos = 0;
			workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
		}
	}
	ret = 0;
	zero_fill_bio(orig_bio);
done:
	if (workspace->in_buf.src)
		kunmap(pages_in[page_in_index]);
	return ret;
}

static int zstd_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);
	ZSTD_DStream *stream;
	int ret = 0;
	size_t ret2;
	unsigned long total_out = 0;
	unsigned long pg_offset = 0;
	char *kaddr;

	stream = ZSTD_initDStream(
			ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
	if (!stream) {
		pr_warn("BTRFS: ZSTD_initDStream failed\n");
		ret = -EIO;
		goto finish;
	}

	destlen = min_t(size_t, destlen, PAGE_SIZE);

	workspace->in_buf.src = data_in;
	workspace->in_buf.pos = 0;
	workspace->in_buf.size = srclen;

	workspace->out_buf.dst = workspace->buf;
	workspace->out_buf.pos = 0;
	workspace->out_buf.size = PAGE_SIZE;

	ret2 = 1;
	while (pg_offset < destlen
	       && workspace->in_buf.pos < workspace->in_buf.size) {
		unsigned long buf_start;
		unsigned long buf_offset;
		unsigned long bytes;

		/* Check if the frame is over and we still need more input */
		if (ret2 == 0) {
			pr_debug("BTRFS: ZSTD_decompressStream ended early\n");
			ret = -EIO;
			goto finish;
		}
		ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
				&workspace->in_buf);
		if (ZSTD_isError(ret2)) {
			pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
					ZSTD_getErrorCode(ret2));
			ret = -EIO;
			goto finish;
		}

		buf_start = total_out;
		total_out += workspace->out_buf.pos;
		workspace->out_buf.pos = 0;

		if (total_out <= start_byte)
			continue;

		if (total_out > start_byte && buf_start < start_byte)
			buf_offset = start_byte - buf_start;
		else
			buf_offset = 0;

		bytes = min_t(unsigned long, destlen - pg_offset,
				workspace->out_buf.size - buf_offset);

		kaddr = kmap_atomic(dest_page);
		memcpy(kaddr + pg_offset, workspace->out_buf.dst + buf_offset,
				bytes);
		kunmap_atomic(kaddr);

		pg_offset += bytes;
	}
	ret = 0;
finish:
	if (pg_offset < destlen) {
		kaddr = kmap_atomic(dest_page);
		memset(kaddr + pg_offset, 0, destlen - pg_offset);
		kunmap_atomic(kaddr);
	}
	return ret;
}

static void zstd_set_level(struct list_head *ws, unsigned int type)
{
}

const struct btrfs_compress_op btrfs_zstd_compress = {
	.alloc_workspace = zstd_alloc_workspace,
	.free_workspace = zstd_free_workspace,
	.compress_pages = zstd_compress_pages,
	.decompress_bio = zstd_decompress_bio,
	.decompress = zstd_decompress,
	.set_level = zstd_set_level,
};
Commit	Line	Data
5c1aab1d NT	1	/*
	2	* Copyright (c) 2016-present, Facebook, Inc.
	3	* All rights reserved.
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public
	7	* License v2 as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	12	* General Public License for more details.
	13	*/
	14	#include <linux/bio.h>
	15	#include <linux/err.h>
	16	#include <linux/init.h>
	17	#include <linux/kernel.h>
	18	#include <linux/mm.h>
	19	#include <linux/pagemap.h>
	20	#include <linux/refcount.h>
	21	#include <linux/sched.h>
	22	#include <linux/slab.h>
	23	#include <linux/zstd.h>
	24	#include "compression.h"
	25
	26	#define ZSTD_BTRFS_MAX_WINDOWLOG 17
	27	#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)
	28	#define ZSTD_BTRFS_DEFAULT_LEVEL 3
	29
	30	static ZSTD_parameters zstd_get_btrfs_parameters(size_t src_len)
	31	{
	32	ZSTD_parameters params = ZSTD_getParams(ZSTD_BTRFS_DEFAULT_LEVEL,
	33	src_len, 0);
	34
	35	if (params.cParams.windowLog > ZSTD_BTRFS_MAX_WINDOWLOG)
	36	params.cParams.windowLog = ZSTD_BTRFS_MAX_WINDOWLOG;
	37	WARN_ON(src_len > ZSTD_BTRFS_MAX_INPUT);
	38	return params;
	39	}
	40
	41	struct workspace {
	42	void *mem;
	43	size_t size;
	44	char *buf;
	45	struct list_head list;
431e9822 DS	46	ZSTD_inBuffer in_buf;
431e9822 DS	47	ZSTD_outBuffer out_buf;
5c1aab1d NT	48	};
	49
	50	static void zstd_free_workspace(struct list_head *ws)
	51	{
	52	struct workspace *workspace = list_entry(ws, struct workspace, list);
	53
	54	kvfree(workspace->mem);
	55	kfree(workspace->buf);
	56	kfree(workspace);
	57	}
	58
	59	static struct list_head *zstd_alloc_workspace(void)
	60	{
	61	ZSTD_parameters params =
	62	zstd_get_btrfs_parameters(ZSTD_BTRFS_MAX_INPUT);
	63	struct workspace *workspace;
	64
	65	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
	66	if (!workspace)
	67	return ERR_PTR(-ENOMEM);
	68
	69	workspace->size = max_t(size_t,
	70	ZSTD_CStreamWorkspaceBound(params.cParams),
	71	ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT));
	72	workspace->mem = kvmalloc(workspace->size, GFP_KERNEL);
	73	workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	74	if (!workspace->mem \|\| !workspace->buf)
	75	goto fail;
	76
	77	INIT_LIST_HEAD(&workspace->list);
	78
	79	return &workspace->list;
	80	fail:
	81	zstd_free_workspace(&workspace->list);
	82	return ERR_PTR(-ENOMEM);
	83	}
	84
	85	static int zstd_compress_pages(struct list_head *ws,
	86	struct address_space *mapping,
	87	u64 start,
	88	struct page **pages,
	89	unsigned long *out_pages,
	90	unsigned long *total_in,
	91	unsigned long *total_out)
	92	{
	93	struct workspace *workspace = list_entry(ws, struct workspace, list);
	94	ZSTD_CStream *stream;
	95	int ret = 0;
	96	int nr_pages = 0;
	97	struct page in_page = NULL; / The current page to read */
	98	struct page out_page = NULL; / The current page to write to */
5c1aab1d NT	99	unsigned long tot_in = 0;
	100	unsigned long tot_out = 0;
	101	unsigned long len = *total_out;
	102	const unsigned long nr_dest_pages = *out_pages;
	103	unsigned long max_out = nr_dest_pages * PAGE_SIZE;
	104	ZSTD_parameters params = zstd_get_btrfs_parameters(len);
	105
	106	*out_pages = 0;
	107	*total_out = 0;
	108	*total_in = 0;
	109
	110	/* Initialize the stream */
	111	stream = ZSTD_initCStream(params, len, workspace->mem,
	112	workspace->size);
	113	if (!stream) {
	114	pr_warn("BTRFS: ZSTD_initCStream failed\n");
	115	ret = -EIO;
	116	goto out;
	117	}
	118
	119	/* map in the first page of input data */
	120	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
431e9822 DS	121	workspace->in_buf.src = kmap(in_page);
	122	workspace->in_buf.pos = 0;
	123	workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
5c1aab1d NT	124
	125
	126	/* Allocate and map in the output buffer */
	127	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	128	if (out_page == NULL) {
	129	ret = -ENOMEM;
	130	goto out;
	131	}
	132	pages[nr_pages++] = out_page;
431e9822 DS	133	workspace->out_buf.dst = kmap(out_page);
	134	workspace->out_buf.pos = 0;
	135	workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
5c1aab1d NT	136
	137	while (1) {
	138	size_t ret2;
	139
431e9822 DS	140	ret2 = ZSTD_compressStream(stream, &workspace->out_buf,
431e9822 DS	141	&workspace->in_buf);
5c1aab1d NT	142	if (ZSTD_isError(ret2)) {
	143	pr_debug("BTRFS: ZSTD_compressStream returned %d\n",
	144	ZSTD_getErrorCode(ret2));
	145	ret = -EIO;
	146	goto out;
	147	}
	148
	149	/* Check to see if we are making it bigger */
431e9822 DS	150	if (tot_in + workspace->in_buf.pos > 8192 &&
	151	tot_in + workspace->in_buf.pos <
	152	tot_out + workspace->out_buf.pos) {
5c1aab1d NT	153	ret = -E2BIG;
	154	goto out;
	155	}
	156
	157	/* We've reached the end of our output range */
431e9822 DS	158	if (workspace->out_buf.pos >= max_out) {
431e9822 DS	159	tot_out += workspace->out_buf.pos;
5c1aab1d NT	160	ret = -E2BIG;
	161	goto out;
	162	}
	163
	164	/* Check if we need more output space */
431e9822	165	if (workspace->out_buf.pos == workspace->out_buf.size) {
5c1aab1d NT	166	tot_out += PAGE_SIZE;
	167	max_out -= PAGE_SIZE;
	168	kunmap(out_page);
	169	if (nr_pages == nr_dest_pages) {
	170	out_page = NULL;
	171	ret = -E2BIG;
	172	goto out;
	173	}
	174	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	175	if (out_page == NULL) {
	176	ret = -ENOMEM;
	177	goto out;
	178	}
	179	pages[nr_pages++] = out_page;
431e9822 DS	180	workspace->out_buf.dst = kmap(out_page);
	181	workspace->out_buf.pos = 0;
	182	workspace->out_buf.size = min_t(size_t, max_out,
	183	PAGE_SIZE);
5c1aab1d NT	184	}
	185
	186	/* We've reached the end of the input */
431e9822 DS	187	if (workspace->in_buf.pos >= len) {
431e9822 DS	188	tot_in += workspace->in_buf.pos;
5c1aab1d NT	189	break;
	190	}
	191
	192	/* Check if we need more input */
431e9822	193	if (workspace->in_buf.pos == workspace->in_buf.size) {
5c1aab1d NT	194	tot_in += PAGE_SIZE;
	195	kunmap(in_page);
	196	put_page(in_page);
	197
	198	start += PAGE_SIZE;
	199	len -= PAGE_SIZE;
	200	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
431e9822 DS	201	workspace->in_buf.src = kmap(in_page);
	202	workspace->in_buf.pos = 0;
	203	workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
5c1aab1d NT	204	}
	205	}
	206	while (1) {
	207	size_t ret2;
	208
431e9822	209	ret2 = ZSTD_endStream(stream, &workspace->out_buf);
5c1aab1d NT	210	if (ZSTD_isError(ret2)) {
	211	pr_debug("BTRFS: ZSTD_endStream returned %d\n",
	212	ZSTD_getErrorCode(ret2));
	213	ret = -EIO;
	214	goto out;
	215	}
	216	if (ret2 == 0) {
431e9822	217	tot_out += workspace->out_buf.pos;
5c1aab1d NT	218	break;
5c1aab1d NT	219	}
431e9822 DS	220	if (workspace->out_buf.pos >= max_out) {
431e9822 DS	221	tot_out += workspace->out_buf.pos;
5c1aab1d NT	222	ret = -E2BIG;
	223	goto out;
	224	}
	225
	226	tot_out += PAGE_SIZE;
	227	max_out -= PAGE_SIZE;
	228	kunmap(out_page);
	229	if (nr_pages == nr_dest_pages) {
	230	out_page = NULL;
	231	ret = -E2BIG;
	232	goto out;
	233	}
	234	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	235	if (out_page == NULL) {
	236	ret = -ENOMEM;
	237	goto out;
	238	}
	239	pages[nr_pages++] = out_page;
431e9822 DS	240	workspace->out_buf.dst = kmap(out_page);
	241	workspace->out_buf.pos = 0;
	242	workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
5c1aab1d NT	243	}
	244
	245	if (tot_out >= tot_in) {
	246	ret = -E2BIG;
	247	goto out;
	248	}
	249
	250	ret = 0;
	251	*total_in = tot_in;
	252	*total_out = tot_out;
	253	out:
	254	*out_pages = nr_pages;
	255	/* Cleanup */
	256	if (in_page) {
	257	kunmap(in_page);
	258	put_page(in_page);
	259	}
	260	if (out_page)
	261	kunmap(out_page);
	262	return ret;
	263	}
	264
	265	static int zstd_decompress_bio(struct list_head ws, struct compressed_bio cb)
	266	{
	267	struct workspace *workspace = list_entry(ws, struct workspace, list);
	268	struct page **pages_in = cb->compressed_pages;
	269	u64 disk_start = cb->start;
	270	struct bio *orig_bio = cb->orig_bio;
	271	size_t srclen = cb->compressed_len;
	272	ZSTD_DStream *stream;
	273	int ret = 0;
	274	unsigned long page_in_index = 0;
	275	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
	276	unsigned long buf_start;
	277	unsigned long total_out = 0;
5c1aab1d NT	278
	279	stream = ZSTD_initDStream(
	280	ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
	281	if (!stream) {
	282	pr_debug("BTRFS: ZSTD_initDStream failed\n");
	283	ret = -EIO;
	284	goto done;
	285	}
	286
431e9822 DS	287	workspace->in_buf.src = kmap(pages_in[page_in_index]);
	288	workspace->in_buf.pos = 0;
	289	workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
5c1aab1d	290
431e9822 DS	291	workspace->out_buf.dst = workspace->buf;
	292	workspace->out_buf.pos = 0;
	293	workspace->out_buf.size = PAGE_SIZE;
5c1aab1d NT	294
	295	while (1) {
	296	size_t ret2;
	297
431e9822 DS	298	ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
431e9822 DS	299	&workspace->in_buf);
5c1aab1d NT	300	if (ZSTD_isError(ret2)) {
	301	pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
	302	ZSTD_getErrorCode(ret2));
	303	ret = -EIO;
	304	goto done;
	305	}
	306	buf_start = total_out;
431e9822 DS	307	total_out += workspace->out_buf.pos;
431e9822 DS	308	workspace->out_buf.pos = 0;
5c1aab1d	309
431e9822 DS	310	ret = btrfs_decompress_buf2page(workspace->out_buf.dst,
431e9822 DS	311	buf_start, total_out, disk_start, orig_bio);
5c1aab1d NT	312	if (ret == 0)
	313	break;
	314
431e9822	315	if (workspace->in_buf.pos >= srclen)
5c1aab1d NT	316	break;
	317
	318	/* Check if we've hit the end of a frame */
	319	if (ret2 == 0)
	320	break;
	321
431e9822	322	if (workspace->in_buf.pos == workspace->in_buf.size) {
5c1aab1d NT	323	kunmap(pages_in[page_in_index++]);
5c1aab1d NT	324	if (page_in_index >= total_pages_in) {
431e9822	325	workspace->in_buf.src = NULL;
5c1aab1d NT	326	ret = -EIO;
	327	goto done;
	328	}
	329	srclen -= PAGE_SIZE;
431e9822 DS	330	workspace->in_buf.src = kmap(pages_in[page_in_index]);
	331	workspace->in_buf.pos = 0;
	332	workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
5c1aab1d NT	333	}
	334	}
	335	ret = 0;
	336	zero_fill_bio(orig_bio);
	337	done:
431e9822	338	if (workspace->in_buf.src)
5c1aab1d NT	339	kunmap(pages_in[page_in_index]);
	340	return ret;
	341	}
	342
	343	static int zstd_decompress(struct list_head ws, unsigned char data_in,
	344	struct page *dest_page,
	345	unsigned long start_byte,
	346	size_t srclen, size_t destlen)
	347	{
	348	struct workspace *workspace = list_entry(ws, struct workspace, list);
	349	ZSTD_DStream *stream;
	350	int ret = 0;
	351	size_t ret2;
5c1aab1d NT	352	unsigned long total_out = 0;
	353	unsigned long pg_offset = 0;
	354	char *kaddr;
	355
	356	stream = ZSTD_initDStream(
	357	ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
	358	if (!stream) {
	359	pr_warn("BTRFS: ZSTD_initDStream failed\n");
	360	ret = -EIO;
	361	goto finish;
	362	}
	363
	364	destlen = min_t(size_t, destlen, PAGE_SIZE);
	365
431e9822 DS	366	workspace->in_buf.src = data_in;
	367	workspace->in_buf.pos = 0;
	368	workspace->in_buf.size = srclen;
5c1aab1d	369
431e9822 DS	370	workspace->out_buf.dst = workspace->buf;
	371	workspace->out_buf.pos = 0;
	372	workspace->out_buf.size = PAGE_SIZE;
5c1aab1d NT	373
5c1aab1d NT	374	ret2 = 1;
431e9822 DS	375	while (pg_offset < destlen
431e9822 DS	376	&& workspace->in_buf.pos < workspace->in_buf.size) {
5c1aab1d NT	377	unsigned long buf_start;
	378	unsigned long buf_offset;
	379	unsigned long bytes;
	380
	381	/* Check if the frame is over and we still need more input */
	382	if (ret2 == 0) {
	383	pr_debug("BTRFS: ZSTD_decompressStream ended early\n");
	384	ret = -EIO;
	385	goto finish;
	386	}
431e9822 DS	387	ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
431e9822 DS	388	&workspace->in_buf);
5c1aab1d NT	389	if (ZSTD_isError(ret2)) {
	390	pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
	391	ZSTD_getErrorCode(ret2));
	392	ret = -EIO;
	393	goto finish;
	394	}
	395
	396	buf_start = total_out;
431e9822 DS	397	total_out += workspace->out_buf.pos;
431e9822 DS	398	workspace->out_buf.pos = 0;
5c1aab1d NT	399
	400	if (total_out <= start_byte)
	401	continue;
	402
	403	if (total_out > start_byte && buf_start < start_byte)
	404	buf_offset = start_byte - buf_start;
	405	else
	406	buf_offset = 0;
	407
	408	bytes = min_t(unsigned long, destlen - pg_offset,
431e9822	409	workspace->out_buf.size - buf_offset);
5c1aab1d NT	410
5c1aab1d NT	411	kaddr = kmap_atomic(dest_page);
431e9822 DS	412	memcpy(kaddr + pg_offset, workspace->out_buf.dst + buf_offset,
431e9822 DS	413	bytes);
5c1aab1d NT	414	kunmap_atomic(kaddr);
	415
	416	pg_offset += bytes;
	417	}
	418	ret = 0;
	419	finish:
	420	if (pg_offset < destlen) {
	421	kaddr = kmap_atomic(dest_page);
	422	memset(kaddr + pg_offset, 0, destlen - pg_offset);
	423	kunmap_atomic(kaddr);
	424	}
	425	return ret;
	426	}
	427
f51d2b59 DS	428	static void zstd_set_level(struct list_head *ws, unsigned int type)
	429	{
	430	}
	431
5c1aab1d NT	432	const struct btrfs_compress_op btrfs_zstd_compress = {
	433	.alloc_workspace = zstd_alloc_workspace,
	434	.free_workspace = zstd_free_workspace,
	435	.compress_pages = zstd_compress_pages,
	436	.decompress_bio = zstd_decompress_bio,
	437	.decompress = zstd_decompress,
f51d2b59	438	.set_level = zstd_set_level,
5c1aab1d	439	};