[mirror_ubuntu-jammy-kernel.git] / fs / btrfs / lzo.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2008 Oracle.  All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/slab.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/lzo.h>
#include <linux/refcount.h>
#include "compression.h"
#include "ctree.h"

#define LZO_LEN	4

/*
 * Btrfs LZO compression format
 *
 * Regular and inlined LZO compressed data extents consist of:
 *
 * 1.  Header
 *     Fixed size. LZO_LEN (4) bytes long, LE32.
 *     Records the total size (including the header) of compressed data.
 *
 * 2.  Segment(s)
 *     Variable size. Each segment includes one segment header, followed by data
 *     payload.
 *     One regular LZO compressed extent can have one or more segments.
 *     For inlined LZO compressed extent, only one segment is allowed.
 *     One segment represents at most one page of uncompressed data.
 *
 * 2.1 Segment header
 *     Fixed size. LZO_LEN (4) bytes long, LE32.
 *     Records the total size of the segment (not including the header).
 *     Segment header never crosses page boundary, thus it's possible to
 *     have at most 3 padding zeros at the end of the page.
 *
 * 2.2 Data Payload
 *     Variable size. Size up limit should be lzo1x_worst_compress(PAGE_SIZE)
 *     which is 4419 for a 4KiB page.
 *
 * Example:
 * Page 1:
 *          0     0x2   0x4   0x6   0x8   0xa   0xc   0xe     0x10
 * 0x0000   |  Header   | SegHdr 01 | Data payload 01 ...     |
 * ...
 * 0x0ff0   | SegHdr  N | Data payload  N     ...          |00|
 *                                                          ^^ padding zeros
 * Page 2:
 * 0x1000   | SegHdr N+1| Data payload N+1 ...                |
 */

struct workspace {
	void *mem;
	void *buf;	/* where decompressed data goes */
	void *cbuf;	/* where compressed data goes */
	struct list_head list;
};

static struct workspace_manager wsm;

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

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

struct list_head *lzo_alloc_workspace(unsigned int level)
{
	struct workspace *workspace;

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

	workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
	workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
	workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
	if (!workspace->mem || !workspace->buf || !workspace->cbuf)
		goto fail;

	INIT_LIST_HEAD(&workspace->list);

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

static inline void write_compress_length(char *buf, size_t len)
{
	__le32 dlen;

	dlen = cpu_to_le32(len);
	memcpy(buf, &dlen, LZO_LEN);
}

static inline size_t read_compress_length(const char *buf)
{
	__le32 dlen;

	memcpy(&dlen, buf, LZO_LEN);
	return le32_to_cpu(dlen);
}

int lzo_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 = 0;
	char *data_in;
	char *cpage_out, *sizes_ptr;
	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;
	size_t in_len;
	size_t out_len;
	char *buf;
	unsigned long tot_in = 0;
	unsigned long tot_out = 0;
	unsigned long pg_bytes_left;
	unsigned long out_offset;
	unsigned long bytes;

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

	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
	data_in = page_address(in_page);

	/*
	 * store the size of all chunks of compressed data in
	 * the first 4 bytes
	 */
	out_page = alloc_page(GFP_NOFS);
	if (out_page == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	cpage_out = page_address(out_page);
	out_offset = LZO_LEN;
	tot_out = LZO_LEN;
	pages[0] = out_page;
	nr_pages = 1;
	pg_bytes_left = PAGE_SIZE - LZO_LEN;

	/* compress at most one page of data each time */
	in_len = min(len, PAGE_SIZE);
	while (tot_in < len) {
		ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
				       &out_len, workspace->mem);
		if (ret != LZO_E_OK) {
			pr_debug("BTRFS: lzo in loop returned %d\n",
			       ret);
			ret = -EIO;
			goto out;
		}

		/* store the size of this chunk of compressed data */
		write_compress_length(cpage_out + out_offset, out_len);
		tot_out += LZO_LEN;
		out_offset += LZO_LEN;
		pg_bytes_left -= LZO_LEN;

		tot_in += in_len;
		tot_out += out_len;

		/* copy bytes from the working buffer into the pages */
		buf = workspace->cbuf;
		while (out_len) {
			bytes = min_t(unsigned long, pg_bytes_left, out_len);

			memcpy(cpage_out + out_offset, buf, bytes);

			out_len -= bytes;
			pg_bytes_left -= bytes;
			buf += bytes;
			out_offset += bytes;

			/*
			 * we need another page for writing out.
			 *
			 * Note if there's less than 4 bytes left, we just
			 * skip to a new page.
			 */
			if ((out_len == 0 && pg_bytes_left < LZO_LEN) ||
			    pg_bytes_left == 0) {
				if (pg_bytes_left) {
					memset(cpage_out + out_offset, 0,
					       pg_bytes_left);
					tot_out += pg_bytes_left;
				}

				/* we're done, don't allocate new page */
				if (out_len == 0 && tot_in >= len)
					break;

				if (nr_pages == nr_dest_pages) {
					out_page = NULL;
					ret = -E2BIG;
					goto out;
				}

				out_page = alloc_page(GFP_NOFS);
				if (out_page == NULL) {
					ret = -ENOMEM;
					goto out;
				}
				cpage_out = page_address(out_page);
				pages[nr_pages++] = out_page;

				pg_bytes_left = PAGE_SIZE;
				out_offset = 0;
			}
		}

		/* we're making it bigger, give up */
		if (tot_in > 8192 && tot_in < tot_out) {
			ret = -E2BIG;
			goto out;
		}

		/* we're all done */
		if (tot_in >= len)
			break;

		if (tot_out > max_out)
			break;

		bytes_left = len - tot_in;
		put_page(in_page);

		start += PAGE_SIZE;
		in_page = find_get_page(mapping, start >> PAGE_SHIFT);
		data_in = page_address(in_page);
		in_len = min(bytes_left, PAGE_SIZE);
	}

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

	/* store the size of all chunks of compressed data */
	sizes_ptr = page_address(pages[0]);
	write_compress_length(sizes_ptr, tot_out);

	ret = 0;
	*total_out = tot_out;
	*total_in = tot_in;
out:
	*out_pages = nr_pages;

	if (in_page)
		put_page(in_page);

	return ret;
}

/*
 * Copy the compressed segment payload into @dest.
 *
 * For the payload there will be no padding, just need to do page switching.
 */
static void copy_compressed_segment(struct compressed_bio *cb,
				    char *dest, u32 len, u32 *cur_in)
{
	u32 orig_in = *cur_in;

	while (*cur_in < orig_in + len) {
		struct page *cur_page;
		u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
					  orig_in + len - *cur_in);

		ASSERT(copy_len);
		cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE];

		memcpy(dest + *cur_in - orig_in,
			page_address(cur_page) + offset_in_page(*cur_in),
			copy_len);

		*cur_in += copy_len;
	}
}

int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	const struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
	const u32 sectorsize = fs_info->sectorsize;
	int ret;
	/* Compressed data length, can be unaligned */
	u32 len_in;
	/* Offset inside the compressed data */
	u32 cur_in = 0;
	/* Bytes decompressed so far */
	u32 cur_out = 0;

	len_in = read_compress_length(page_address(cb->compressed_pages[0]));
	cur_in += LZO_LEN;

	/*
	 * LZO header length check
	 *
	 * The total length should not exceed the maximum extent length,
	 * and all sectors should be used.
	 * If this happens, it means the compressed extent is corrupted.
	 */
	if (len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) ||
	    round_up(len_in, sectorsize) < cb->compressed_len) {
		btrfs_err(fs_info,
			"invalid lzo header, lzo len %u compressed len %u",
			len_in, cb->compressed_len);
		return -EUCLEAN;
	}

	/* Go through each lzo segment */
	while (cur_in < len_in) {
		struct page *cur_page;
		/* Length of the compressed segment */
		u32 seg_len;
		u32 sector_bytes_left;
		size_t out_len = lzo1x_worst_compress(sectorsize);

		/*
		 * We should always have enough space for one segment header
		 * inside current sector.
		 */
		ASSERT(cur_in / sectorsize ==
		       (cur_in + LZO_LEN - 1) / sectorsize);
		cur_page = cb->compressed_pages[cur_in / PAGE_SIZE];
		ASSERT(cur_page);
		seg_len = read_compress_length(page_address(cur_page) +
					       offset_in_page(cur_in));
		cur_in += LZO_LEN;

		/* Copy the compressed segment payload into workspace */
		copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in);

		/* Decompress the data */
		ret = lzo1x_decompress_safe(workspace->cbuf, seg_len,
					    workspace->buf, &out_len);
		if (ret != LZO_E_OK) {
			btrfs_err(fs_info, "failed to decompress");
			ret = -EIO;
			goto out;
		}

		/* Copy the data into inode pages */
		ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out);
		cur_out += out_len;

		/* All data read, exit */
		if (ret == 0)
			goto out;
		ret = 0;

		/* Check if the sector has enough space for a segment header */
		sector_bytes_left = sectorsize - (cur_in % sectorsize);
		if (sector_bytes_left >= LZO_LEN)
			continue;

		/* Skip the padding zeros */
		cur_in += sector_bytes_left;
	}
out:
	if (!ret)
		zero_fill_bio(cb->orig_bio);
	return ret;
}

int lzo_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);
	size_t in_len;
	size_t out_len;
	size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
	int ret = 0;
	char *kaddr;
	unsigned long bytes;

	if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2)
		return -EUCLEAN;

	in_len = read_compress_length(data_in);
	if (in_len != srclen)
		return -EUCLEAN;
	data_in += LZO_LEN;

	in_len = read_compress_length(data_in);
	if (in_len != srclen - LZO_LEN * 2) {
		ret = -EUCLEAN;
		goto out;
	}
	data_in += LZO_LEN;

	out_len = PAGE_SIZE;
	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
	if (ret != LZO_E_OK) {
		pr_warn("BTRFS: decompress failed!\n");
		ret = -EIO;
		goto out;
	}

	if (out_len < start_byte) {
		ret = -EIO;
		goto out;
	}

	/*
	 * the caller is already checking against PAGE_SIZE, but lets
	 * move this check closer to the memcpy/memset
	 */
	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
	bytes = min_t(unsigned long, destlen, out_len - start_byte);

	kaddr = page_address(dest_page);
	memcpy(kaddr, workspace->buf + start_byte, bytes);

	/*
	 * btrfs_getblock is doing a zero on the tail of the page too,
	 * but this will cover anything missing from the decompressed
	 * data.
	 */
	if (bytes < destlen)
		memset(kaddr+bytes, 0, destlen-bytes);
out:
	return ret;
}

const struct btrfs_compress_op btrfs_lzo_compress = {
	.workspace_manager	= &wsm,
	.max_level		= 1,
	.default_level		= 1,
};
Commit	Line	Data
c1d7c514	1	// SPDX-License-Identifier: GPL-2.0
a6fa6fae LZ	2	/*
a6fa6fae LZ	3	* Copyright (C) 2008 Oracle. All rights reserved.
a6fa6fae LZ	4	*/
	5
	6	#include <linux/kernel.h>
	7	#include <linux/slab.h>
6acafd1e	8	#include <linux/mm.h>
a6fa6fae LZ	9	#include <linux/init.h>
	10	#include <linux/err.h>
	11	#include <linux/sched.h>
	12	#include <linux/pagemap.h>
	13	#include <linux/bio.h>
	14	#include <linux/lzo.h>
e1ddce71	15	#include <linux/refcount.h>
a6fa6fae	16	#include "compression.h"
a6e66e6f	17	#include "ctree.h"
a6fa6fae LZ	18
	19	#define LZO_LEN 4
	20
2a1f7c0c QW	21	/*
	22	* Btrfs LZO compression format
	23	*
	24	* Regular and inlined LZO compressed data extents consist of:
	25	*
	26	* 1. Header
	27	* Fixed size. LZO_LEN (4) bytes long, LE32.
	28	* Records the total size (including the header) of compressed data.
	29	*
	30	* 2. Segment(s)
52042d8e	31	* Variable size. Each segment includes one segment header, followed by data
2a1f7c0c QW	32	* payload.
	33	* One regular LZO compressed extent can have one or more segments.
	34	* For inlined LZO compressed extent, only one segment is allowed.
	35	* One segment represents at most one page of uncompressed data.
	36	*
	37	* 2.1 Segment header
	38	* Fixed size. LZO_LEN (4) bytes long, LE32.
	39	* Records the total size of the segment (not including the header).
	40	* Segment header never crosses page boundary, thus it's possible to
	41	* have at most 3 padding zeros at the end of the page.
	42	*
	43	* 2.2 Data Payload
	44	* Variable size. Size up limit should be lzo1x_worst_compress(PAGE_SIZE)
	45	* which is 4419 for a 4KiB page.
	46	*
	47	* Example:
	48	* Page 1:
	49	* 0 0x2 0x4 0x6 0x8 0xa 0xc 0xe 0x10
	50	* 0x0000 \| Header \| SegHdr 01 \| Data payload 01 ... \|
	51	* ...
	52	* 0x0ff0 \| SegHdr N \| Data payload N ... \|00\|
	53	* ^^ padding zeros
	54	* Page 2:
	55	* 0x1000 \| SegHdr N+1\| Data payload N+1 ... \|
	56	*/
	57
a6fa6fae LZ	58	struct workspace {
a6fa6fae LZ	59	void *mem;
3fb40375 JL	60	void buf; / where decompressed data goes */
3fb40375 JL	61	void cbuf; / where compressed data goes */
a6fa6fae LZ	62	struct list_head list;
	63	};
	64
92ee5530 DZ	65	static struct workspace_manager wsm;
92ee5530 DZ	66
d20f395f	67	void lzo_free_workspace(struct list_head *ws)
a6fa6fae LZ	68	{
	69	struct workspace *workspace = list_entry(ws, struct workspace, list);
	70
6acafd1e DS	71	kvfree(workspace->buf);
	72	kvfree(workspace->cbuf);
	73	kvfree(workspace->mem);
a6fa6fae LZ	74	kfree(workspace);
	75	}
	76
d20f395f	77	struct list_head *lzo_alloc_workspace(unsigned int level)
a6fa6fae LZ	78	{
	79	struct workspace *workspace;
	80
389a6cfc	81	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
a6fa6fae LZ	82	if (!workspace)
	83	return ERR_PTR(-ENOMEM);
	84
6acafd1e DS	85	workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
	86	workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
	87	workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
a6fa6fae LZ	88	if (!workspace->mem \|\| !workspace->buf \|\| !workspace->cbuf)
	89	goto fail;
	90
	91	INIT_LIST_HEAD(&workspace->list);
	92
	93	return &workspace->list;
	94	fail:
	95	lzo_free_workspace(&workspace->list);
	96	return ERR_PTR(-ENOMEM);
	97	}
	98
	99	static inline void write_compress_length(char *buf, size_t len)
	100	{
	101	__le32 dlen;
	102
	103	dlen = cpu_to_le32(len);
	104	memcpy(buf, &dlen, LZO_LEN);
	105	}
	106
14a3357b	107	static inline size_t read_compress_length(const char *buf)
a6fa6fae LZ	108	{
	109	__le32 dlen;
	110
	111	memcpy(&dlen, buf, LZO_LEN);
	112	return le32_to_cpu(dlen);
	113	}
	114
c4bf665a DS	115	int lzo_compress_pages(struct list_head ws, struct address_space mapping,
	116	u64 start, struct page *pages, unsigned long out_pages,
	117	unsigned long total_in, unsigned long total_out)
a6fa6fae LZ	118	{
	119	struct workspace *workspace = list_entry(ws, struct workspace, list);
	120	int ret = 0;
	121	char *data_in;
58c1a35c	122	char cpage_out, sizes_ptr;
a6fa6fae LZ	123	int nr_pages = 0;
	124	struct page *in_page = NULL;
	125	struct page *out_page = NULL;
	126	unsigned long bytes_left;
38c31464	127	unsigned long len = *total_out;
4d3a800e	128	unsigned long nr_dest_pages = *out_pages;
e5d74902	129	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
a6fa6fae LZ	130	size_t in_len;
	131	size_t out_len;
	132	char *buf;
	133	unsigned long tot_in = 0;
	134	unsigned long tot_out = 0;
	135	unsigned long pg_bytes_left;
	136	unsigned long out_offset;
	137	unsigned long bytes;
	138
	139	*out_pages = 0;
	140	*total_out = 0;
	141	*total_in = 0;
	142
09cbfeaf	143	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
8c945d32	144	data_in = page_address(in_page);
a6fa6fae LZ	145
	146	/*
	147	* store the size of all chunks of compressed data in
	148	* the first 4 bytes
	149	*/
b0ee5e1e	150	out_page = alloc_page(GFP_NOFS);
a6fa6fae LZ	151	if (out_page == NULL) {
	152	ret = -ENOMEM;
	153	goto out;
	154	}
8c945d32	155	cpage_out = page_address(out_page);
a6fa6fae LZ	156	out_offset = LZO_LEN;
	157	tot_out = LZO_LEN;
	158	pages[0] = out_page;
	159	nr_pages = 1;
09cbfeaf	160	pg_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	161
a6fa6fae LZ	162	/* compress at most one page of data each time */
09cbfeaf	163	in_len = min(len, PAGE_SIZE);
a6fa6fae LZ	164	while (tot_in < len) {
	165	ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
	166	&out_len, workspace->mem);
	167	if (ret != LZO_E_OK) {
036b0217	168	pr_debug("BTRFS: lzo in loop returned %d\n",
a6fa6fae	169	ret);
60e1975a	170	ret = -EIO;
a6fa6fae LZ	171	goto out;
	172	}
	173
	174	/* store the size of this chunk of compressed data */
	175	write_compress_length(cpage_out + out_offset, out_len);
	176	tot_out += LZO_LEN;
	177	out_offset += LZO_LEN;
	178	pg_bytes_left -= LZO_LEN;
	179
	180	tot_in += in_len;
	181	tot_out += out_len;
	182
	183	/* copy bytes from the working buffer into the pages */
	184	buf = workspace->cbuf;
	185	while (out_len) {
	186	bytes = min_t(unsigned long, pg_bytes_left, out_len);
	187
	188	memcpy(cpage_out + out_offset, buf, bytes);
	189
	190	out_len -= bytes;
	191	pg_bytes_left -= bytes;
	192	buf += bytes;
	193	out_offset += bytes;
	194
	195	/*
	196	* we need another page for writing out.
	197	*
	198	* Note if there's less than 4 bytes left, we just
	199	* skip to a new page.
	200	*/
	201	if ((out_len == 0 && pg_bytes_left < LZO_LEN) \|\|
	202	pg_bytes_left == 0) {
	203	if (pg_bytes_left) {
	204	memset(cpage_out + out_offset, 0,
	205	pg_bytes_left);
	206	tot_out += pg_bytes_left;
	207	}
	208
	209	/* we're done, don't allocate new page */
	210	if (out_len == 0 && tot_in >= len)
	211	break;
	212
a6fa6fae LZ	213	if (nr_pages == nr_dest_pages) {
a6fa6fae LZ	214	out_page = NULL;
60e1975a	215	ret = -E2BIG;
a6fa6fae LZ	216	goto out;
	217	}
	218
b0ee5e1e	219	out_page = alloc_page(GFP_NOFS);
a6fa6fae LZ	220	if (out_page == NULL) {
	221	ret = -ENOMEM;
	222	goto out;
	223	}
8c945d32	224	cpage_out = page_address(out_page);
a6fa6fae LZ	225	pages[nr_pages++] = out_page;
a6fa6fae LZ	226
09cbfeaf	227	pg_bytes_left = PAGE_SIZE;
a6fa6fae LZ	228	out_offset = 0;
	229	}
	230	}
	231
	232	/* we're making it bigger, give up */
59516f60	233	if (tot_in > 8192 && tot_in < tot_out) {
60e1975a	234	ret = -E2BIG;
a6fa6fae	235	goto out;
59516f60	236	}
a6fa6fae LZ	237
	238	/* we're all done */
	239	if (tot_in >= len)
	240	break;
	241
	242	if (tot_out > max_out)
	243	break;
	244
	245	bytes_left = len - tot_in;
09cbfeaf	246	put_page(in_page);
a6fa6fae	247
09cbfeaf KS	248	start += PAGE_SIZE;
09cbfeaf KS	249	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
8c945d32	250	data_in = page_address(in_page);
09cbfeaf	251	in_len = min(bytes_left, PAGE_SIZE);
a6fa6fae LZ	252	}
a6fa6fae LZ	253
1e9d7291 TT	254	if (tot_out >= tot_in) {
1e9d7291 TT	255	ret = -E2BIG;
a6fa6fae	256	goto out;
1e9d7291	257	}
a6fa6fae LZ	258
a6fa6fae LZ	259	/* store the size of all chunks of compressed data */
8c945d32	260	sizes_ptr = page_address(pages[0]);
58c1a35c	261	write_compress_length(sizes_ptr, tot_out);
a6fa6fae LZ	262
	263	ret = 0;
	264	*total_out = tot_out;
	265	*total_in = tot_in;
	266	out:
	267	*out_pages = nr_pages;
a6fa6fae	268
8c945d32	269	if (in_page)
09cbfeaf	270	put_page(in_page);
a6fa6fae LZ	271
	272	return ret;
	273	}
	274
a6e66e6f QW	275	/*
	276	* Copy the compressed segment payload into @dest.
	277	*
	278	* For the payload there will be no padding, just need to do page switching.
	279	*/
	280	static void copy_compressed_segment(struct compressed_bio *cb,
	281	char dest, u32 len, u32 cur_in)
	282	{
	283	u32 orig_in = *cur_in;
	284
	285	while (*cur_in < orig_in + len) {
	286	struct page *cur_page;
	287	u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
	288	orig_in + len - *cur_in);
	289
	290	ASSERT(copy_len);
	291	cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE];
	292
	293	memcpy(dest + *cur_in - orig_in,
	294	page_address(cur_page) + offset_in_page(*cur_in),
	295	copy_len);
	296
	297	*cur_in += copy_len;
	298	}
	299	}
	300
c4bf665a	301	int lzo_decompress_bio(struct list_head ws, struct compressed_bio cb)
a6fa6fae LZ	302	{
a6fa6fae LZ	303	struct workspace *workspace = list_entry(ws, struct workspace, list);
a6e66e6f QW	304	const struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb);
	305	const u32 sectorsize = fs_info->sectorsize;
	306	int ret;
	307	/* Compressed data length, can be unaligned */
	308	u32 len_in;
	309	/* Offset inside the compressed data */
	310	u32 cur_in = 0;
	311	/* Bytes decompressed so far */
	312	u32 cur_out = 0;
	313
	314	len_in = read_compress_length(page_address(cb->compressed_pages[0]));
	315	cur_in += LZO_LEN;
a6fa6fae	316
314bfa47	317	/*
a6e66e6f	318	* LZO header length check
314bfa47	319	*
a6e66e6f QW	320	* The total length should not exceed the maximum extent length,
	321	* and all sectors should be used.
	322	* If this happens, it means the compressed extent is corrupted.
314bfa47	323	*/
a6e66e6f QW	324	if (len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) \|\|
	325	round_up(len_in, sectorsize) < cb->compressed_len) {
	326	btrfs_err(fs_info,
	327	"invalid lzo header, lzo len %u compressed len %u",
	328	len_in, cb->compressed_len);
	329	return -EUCLEAN;
314bfa47	330	}
a6fa6fae	331
a6e66e6f QW	332	/* Go through each lzo segment */
	333	while (cur_in < len_in) {
	334	struct page *cur_page;
	335	/* Length of the compressed segment */
	336	u32 seg_len;
	337	u32 sector_bytes_left;
	338	size_t out_len = lzo1x_worst_compress(sectorsize);
a6fa6fae	339
314bfa47	340	/*
a6e66e6f QW	341	* We should always have enough space for one segment header
a6e66e6f QW	342	* inside current sector.
314bfa47	343	*/
a6e66e6f QW	344	ASSERT(cur_in / sectorsize ==
	345	(cur_in + LZO_LEN - 1) / sectorsize);
	346	cur_page = cb->compressed_pages[cur_in / PAGE_SIZE];
	347	ASSERT(cur_page);
	348	seg_len = read_compress_length(page_address(cur_page) +
	349	offset_in_page(cur_in));
	350	cur_in += LZO_LEN;
	351
	352	/* Copy the compressed segment payload into workspace */
	353	copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in);
	354
	355	/* Decompress the data */
	356	ret = lzo1x_decompress_safe(workspace->cbuf, seg_len,
	357	workspace->buf, &out_len);
a6fa6fae	358	if (ret != LZO_E_OK) {
a6e66e6f	359	btrfs_err(fs_info, "failed to decompress");
60e1975a	360	ret = -EIO;
a6e66e6f	361	goto out;
a6fa6fae LZ	362	}
a6fa6fae LZ	363
a6e66e6f QW	364	/* Copy the data into inode pages */
	365	ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out);
	366	cur_out += out_len;
a6fa6fae	367
a6e66e6f QW	368	/* All data read, exit */
	369	if (ret == 0)
	370	goto out;
	371	ret = 0;
	372
	373	/* Check if the sector has enough space for a segment header */
	374	sector_bytes_left = sectorsize - (cur_in % sectorsize);
	375	if (sector_bytes_left >= LZO_LEN)
	376	continue;
	377
	378	/* Skip the padding zeros */
	379	cur_in += sector_bytes_left;
a6fa6fae	380	}
a6e66e6f	381	out:
2f19cad9	382	if (!ret)
1c3dc173	383	zero_fill_bio(cb->orig_bio);
a6fa6fae LZ	384	return ret;
	385	}
	386
c4bf665a DS	387	int lzo_decompress(struct list_head ws, unsigned char data_in,
	388	struct page *dest_page, unsigned long start_byte, size_t srclen,
	389	size_t destlen)
a6fa6fae LZ	390	{
	391	struct workspace *workspace = list_entry(ws, struct workspace, list);
	392	size_t in_len;
	393	size_t out_len;
de885e3e	394	size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	395	int ret = 0;
	396	char *kaddr;
	397	unsigned long bytes;
	398
de885e3e QW	399	if (srclen < LZO_LEN \|\| srclen > max_segment_len + LZO_LEN * 2)
de885e3e QW	400	return -EUCLEAN;
a6fa6fae	401
de885e3e QW	402	in_len = read_compress_length(data_in);
	403	if (in_len != srclen)
	404	return -EUCLEAN;
a6fa6fae LZ	405	data_in += LZO_LEN;
	406
	407	in_len = read_compress_length(data_in);
de885e3e QW	408	if (in_len != srclen - LZO_LEN * 2) {
	409	ret = -EUCLEAN;
	410	goto out;
	411	}
a6fa6fae LZ	412	data_in += LZO_LEN;
a6fa6fae LZ	413
09cbfeaf	414	out_len = PAGE_SIZE;
a6fa6fae LZ	415	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
a6fa6fae LZ	416	if (ret != LZO_E_OK) {
62e85577	417	pr_warn("BTRFS: decompress failed!\n");
60e1975a	418	ret = -EIO;
a6fa6fae LZ	419	goto out;
	420	}
	421
	422	if (out_len < start_byte) {
60e1975a	423	ret = -EIO;
a6fa6fae LZ	424	goto out;
	425	}
	426
2f19cad9 CM	427	/*
	428	* the caller is already checking against PAGE_SIZE, but lets
	429	* move this check closer to the memcpy/memset
	430	*/
	431	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
a6fa6fae LZ	432	bytes = min_t(unsigned long, destlen, out_len - start_byte);
a6fa6fae LZ	433
8c945d32	434	kaddr = page_address(dest_page);
a6fa6fae	435	memcpy(kaddr, workspace->buf + start_byte, bytes);
2f19cad9 CM	436
	437	/*
	438	* btrfs_getblock is doing a zero on the tail of the page too,
	439	* but this will cover anything missing from the decompressed
	440	* data.
	441	*/
	442	if (bytes < destlen)
	443	memset(kaddr+bytes, 0, destlen-bytes);
a6fa6fae LZ	444	out:
	445	return ret;
	446	}
	447
e8c9f186	448	const struct btrfs_compress_op btrfs_lzo_compress = {
be951045	449	.workspace_manager = &wsm,
e18333a7 DS	450	.max_level = 1,
e18333a7 DS	451	.default_level = 1,
a6fa6fae	452	};