[linux.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"

#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;
	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 = kmap(in_page);

	/*
	 * store the size of all chunks of compressed data in
	 * the first 4 bytes
	 */
	out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
	if (out_page == NULL) {
		ret = -ENOMEM;
		goto out;
	}
	cpage_out = kmap(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;

				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;

				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;
		kunmap(in_page);
		put_page(in_page);

		start += PAGE_SIZE;
		in_page = find_get_page(mapping, start >> PAGE_SHIFT);
		data_in = kmap(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 */
	cpage_out = kmap(pages[0]);
	write_compress_length(cpage_out, tot_out);

	kunmap(pages[0]);

	ret = 0;
	*total_out = tot_out;
	*total_in = tot_in;
out:
	*out_pages = nr_pages;
	if (out_page)
		kunmap(out_page);

	if (in_page) {
		kunmap(in_page);
		put_page(in_page);
	}

	return ret;
}

int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
{
	struct workspace *workspace = list_entry(ws, struct workspace, list);
	int ret = 0, ret2;
	char *data_in;
	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;
	unsigned long buf_offset = 0;
	unsigned long bytes;
	unsigned long working_bytes;
	size_t in_len;
	size_t out_len;
	const size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
	unsigned long in_offset;
	unsigned long in_page_bytes_left;
	unsigned long tot_in;
	unsigned long tot_out;
	unsigned long tot_len;
	char *buf;
	bool may_late_unmap, need_unmap;
	struct page **pages_in = cb->compressed_pages;
	u64 disk_start = cb->start;
	struct bio *orig_bio = cb->orig_bio;

	data_in = kmap(pages_in[0]);
	tot_len = read_compress_length(data_in);
	/*
	 * Compressed data header check.
	 *
	 * The real compressed size can't exceed the maximum extent length, and
	 * all pages should be used (whole unused page with just the segment
	 * header is not possible).  If this happens it means the compressed
	 * extent is corrupted.
	 */
	if (tot_len > min_t(size_t, BTRFS_MAX_COMPRESSED, srclen) ||
	    tot_len < srclen - PAGE_SIZE) {
		ret = -EUCLEAN;
		goto done;
	}

	tot_in = LZO_LEN;
	in_offset = LZO_LEN;
	in_page_bytes_left = PAGE_SIZE - LZO_LEN;

	tot_out = 0;

	while (tot_in < tot_len) {
		in_len = read_compress_length(data_in + in_offset);
		in_page_bytes_left -= LZO_LEN;
		in_offset += LZO_LEN;
		tot_in += LZO_LEN;

		/*
		 * Segment header check.
		 *
		 * The segment length must not exceed the maximum LZO
		 * compression size, nor the total compressed size.
		 */
		if (in_len > max_segment_len || tot_in + in_len > tot_len) {
			ret = -EUCLEAN;
			goto done;
		}

		tot_in += in_len;
		working_bytes = in_len;
		may_late_unmap = need_unmap = false;

		/* fast path: avoid using the working buffer */
		if (in_page_bytes_left >= in_len) {
			buf = data_in + in_offset;
			bytes = in_len;
			may_late_unmap = true;
			goto cont;
		}

		/* copy bytes from the pages into the working buffer */
		buf = workspace->cbuf;
		buf_offset = 0;
		while (working_bytes) {
			bytes = min(working_bytes, in_page_bytes_left);

			memcpy(buf + buf_offset, data_in + in_offset, bytes);
			buf_offset += bytes;
cont:
			working_bytes -= bytes;
			in_page_bytes_left -= bytes;
			in_offset += bytes;

			/* check if we need to pick another page */
			if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
			    || in_page_bytes_left == 0) {
				tot_in += in_page_bytes_left;

				if (working_bytes == 0 && tot_in >= tot_len)
					break;

				if (page_in_index + 1 >= total_pages_in) {
					ret = -EIO;
					goto done;
				}

				if (may_late_unmap)
					need_unmap = true;
				else
					kunmap(pages_in[page_in_index]);

				data_in = kmap(pages_in[++page_in_index]);

				in_page_bytes_left = PAGE_SIZE;
				in_offset = 0;
			}
		}

		out_len = max_segment_len;
		ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
					    &out_len);
		if (need_unmap)
			kunmap(pages_in[page_in_index - 1]);
		if (ret != LZO_E_OK) {
			pr_warn("BTRFS: decompress failed\n");
			ret = -EIO;
			break;
		}

		buf_start = tot_out;
		tot_out += out_len;

		ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
						 tot_out, disk_start, orig_bio);
		if (ret2 == 0)
			break;
	}
done:
	kunmap(pages_in[page_in_index]);
	if (!ret)
		zero_fill_bio(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 = kmap_atomic(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);
	kunmap_atomic(kaddr);
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 LZ	16	#include "compression.h"
	17
	18	#define LZO_LEN 4
	19
2a1f7c0c QW	20	/*
	21	* Btrfs LZO compression format
	22	*
	23	* Regular and inlined LZO compressed data extents consist of:
	24	*
	25	* 1. Header
	26	* Fixed size. LZO_LEN (4) bytes long, LE32.
	27	* Records the total size (including the header) of compressed data.
	28	*
	29	* 2. Segment(s)
52042d8e	30	* Variable size. Each segment includes one segment header, followed by data
2a1f7c0c QW	31	* payload.
	32	* One regular LZO compressed extent can have one or more segments.
	33	* For inlined LZO compressed extent, only one segment is allowed.
	34	* One segment represents at most one page of uncompressed data.
	35	*
	36	* 2.1 Segment header
	37	* Fixed size. LZO_LEN (4) bytes long, LE32.
	38	* Records the total size of the segment (not including the header).
	39	* Segment header never crosses page boundary, thus it's possible to
	40	* have at most 3 padding zeros at the end of the page.
	41	*
	42	* 2.2 Data Payload
	43	* Variable size. Size up limit should be lzo1x_worst_compress(PAGE_SIZE)
	44	* which is 4419 for a 4KiB page.
	45	*
	46	* Example:
	47	* Page 1:
	48	* 0 0x2 0x4 0x6 0x8 0xa 0xc 0xe 0x10
	49	* 0x0000 \| Header \| SegHdr 01 \| Data payload 01 ... \|
	50	* ...
	51	* 0x0ff0 \| SegHdr N \| Data payload N ... \|00\|
	52	* ^^ padding zeros
	53	* Page 2:
	54	* 0x1000 \| SegHdr N+1\| Data payload N+1 ... \|
	55	*/
	56
a6fa6fae LZ	57	struct workspace {
a6fa6fae LZ	58	void *mem;
3fb40375 JL	59	void buf; / where decompressed data goes */
3fb40375 JL	60	void cbuf; / where compressed data goes */
a6fa6fae LZ	61	struct list_head list;
	62	};
	63
92ee5530 DZ	64	static struct workspace_manager wsm;
92ee5530 DZ	65
d20f395f	66	void lzo_free_workspace(struct list_head *ws)
a6fa6fae LZ	67	{
	68	struct workspace *workspace = list_entry(ws, struct workspace, list);
	69
6acafd1e DS	70	kvfree(workspace->buf);
	71	kvfree(workspace->cbuf);
	72	kvfree(workspace->mem);
a6fa6fae LZ	73	kfree(workspace);
	74	}
	75
d20f395f	76	struct list_head *lzo_alloc_workspace(unsigned int level)
a6fa6fae LZ	77	{
	78	struct workspace *workspace;
	79
389a6cfc	80	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
a6fa6fae LZ	81	if (!workspace)
	82	return ERR_PTR(-ENOMEM);
	83
6acafd1e DS	84	workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
	85	workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
	86	workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
a6fa6fae LZ	87	if (!workspace->mem \|\| !workspace->buf \|\| !workspace->cbuf)
	88	goto fail;
	89
	90	INIT_LIST_HEAD(&workspace->list);
	91
	92	return &workspace->list;
	93	fail:
	94	lzo_free_workspace(&workspace->list);
	95	return ERR_PTR(-ENOMEM);
	96	}
	97
	98	static inline void write_compress_length(char *buf, size_t len)
	99	{
	100	__le32 dlen;
	101
	102	dlen = cpu_to_le32(len);
	103	memcpy(buf, &dlen, LZO_LEN);
	104	}
	105
14a3357b	106	static inline size_t read_compress_length(const char *buf)
a6fa6fae LZ	107	{
	108	__le32 dlen;
	109
	110	memcpy(&dlen, buf, LZO_LEN);
	111	return le32_to_cpu(dlen);
	112	}
	113
c4bf665a DS	114	int lzo_compress_pages(struct list_head ws, struct address_space mapping,
	115	u64 start, struct page *pages, unsigned long out_pages,
	116	unsigned long total_in, unsigned long total_out)
a6fa6fae LZ	117	{
	118	struct workspace *workspace = list_entry(ws, struct workspace, list);
	119	int ret = 0;
	120	char *data_in;
	121	char *cpage_out;
	122	int nr_pages = 0;
	123	struct page *in_page = NULL;
	124	struct page *out_page = NULL;
	125	unsigned long bytes_left;
38c31464	126	unsigned long len = *total_out;
4d3a800e	127	unsigned long nr_dest_pages = *out_pages;
e5d74902	128	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
a6fa6fae LZ	129	size_t in_len;
	130	size_t out_len;
	131	char *buf;
	132	unsigned long tot_in = 0;
	133	unsigned long tot_out = 0;
	134	unsigned long pg_bytes_left;
	135	unsigned long out_offset;
	136	unsigned long bytes;
	137
	138	*out_pages = 0;
	139	*total_out = 0;
	140	*total_in = 0;
	141
09cbfeaf	142	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
a6fa6fae LZ	143	data_in = kmap(in_page);
	144
	145	/*
	146	* store the size of all chunks of compressed data in
	147	* the first 4 bytes
	148	*/
	149	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	150	if (out_page == NULL) {
	151	ret = -ENOMEM;
	152	goto out;
	153	}
	154	cpage_out = kmap(out_page);
	155	out_offset = LZO_LEN;
	156	tot_out = LZO_LEN;
	157	pages[0] = out_page;
	158	nr_pages = 1;
09cbfeaf	159	pg_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	160
a6fa6fae LZ	161	/* compress at most one page of data each time */
09cbfeaf	162	in_len = min(len, PAGE_SIZE);
a6fa6fae LZ	163	while (tot_in < len) {
	164	ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
	165	&out_len, workspace->mem);
	166	if (ret != LZO_E_OK) {
036b0217	167	pr_debug("BTRFS: lzo in loop returned %d\n",
a6fa6fae	168	ret);
60e1975a	169	ret = -EIO;
a6fa6fae LZ	170	goto out;
	171	}
	172
	173	/* store the size of this chunk of compressed data */
	174	write_compress_length(cpage_out + out_offset, out_len);
	175	tot_out += LZO_LEN;
	176	out_offset += LZO_LEN;
	177	pg_bytes_left -= LZO_LEN;
	178
	179	tot_in += in_len;
	180	tot_out += out_len;
	181
	182	/* copy bytes from the working buffer into the pages */
	183	buf = workspace->cbuf;
	184	while (out_len) {
	185	bytes = min_t(unsigned long, pg_bytes_left, out_len);
	186
	187	memcpy(cpage_out + out_offset, buf, bytes);
	188
	189	out_len -= bytes;
	190	pg_bytes_left -= bytes;
	191	buf += bytes;
	192	out_offset += bytes;
	193
	194	/*
	195	* we need another page for writing out.
	196	*
	197	* Note if there's less than 4 bytes left, we just
	198	* skip to a new page.
	199	*/
	200	if ((out_len == 0 && pg_bytes_left < LZO_LEN) \|\|
	201	pg_bytes_left == 0) {
	202	if (pg_bytes_left) {
	203	memset(cpage_out + out_offset, 0,
	204	pg_bytes_left);
	205	tot_out += pg_bytes_left;
	206	}
	207
	208	/* we're done, don't allocate new page */
	209	if (out_len == 0 && tot_in >= len)
	210	break;
	211
	212	kunmap(out_page);
	213	if (nr_pages == nr_dest_pages) {
	214	out_page = NULL;
60e1975a	215	ret = -E2BIG;
a6fa6fae LZ	216	goto out;
	217	}
	218
	219	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	220	if (out_page == NULL) {
	221	ret = -ENOMEM;
	222	goto out;
	223	}
	224	cpage_out = kmap(out_page);
	225	pages[nr_pages++] = out_page;
	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;
	246	kunmap(in_page);
09cbfeaf	247	put_page(in_page);
a6fa6fae	248
09cbfeaf KS	249	start += PAGE_SIZE;
09cbfeaf KS	250	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
a6fa6fae	251	data_in = kmap(in_page);
09cbfeaf	252	in_len = min(bytes_left, PAGE_SIZE);
a6fa6fae LZ	253	}
a6fa6fae LZ	254
1e9d7291 TT	255	if (tot_out >= tot_in) {
1e9d7291 TT	256	ret = -E2BIG;
a6fa6fae	257	goto out;
1e9d7291	258	}
a6fa6fae LZ	259
	260	/* store the size of all chunks of compressed data */
	261	cpage_out = kmap(pages[0]);
	262	write_compress_length(cpage_out, tot_out);
	263
	264	kunmap(pages[0]);
	265
	266	ret = 0;
	267	*total_out = tot_out;
	268	*total_in = tot_in;
	269	out:
	270	*out_pages = nr_pages;
	271	if (out_page)
	272	kunmap(out_page);
	273
	274	if (in_page) {
	275	kunmap(in_page);
09cbfeaf	276	put_page(in_page);
a6fa6fae LZ	277	}
	278
	279	return ret;
	280	}
	281
c4bf665a	282	int lzo_decompress_bio(struct list_head ws, struct compressed_bio cb)
a6fa6fae LZ	283	{
a6fa6fae LZ	284	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	285	int ret = 0, ret2;
a6fa6fae	286	char *data_in;
a6fa6fae	287	unsigned long page_in_index = 0;
e1ddce71	288	size_t srclen = cb->compressed_len;
09cbfeaf	289	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
a6fa6fae LZ	290	unsigned long buf_start;
	291	unsigned long buf_offset = 0;
	292	unsigned long bytes;
	293	unsigned long working_bytes;
a6fa6fae LZ	294	size_t in_len;
a6fa6fae LZ	295	size_t out_len;
314bfa47	296	const size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	297	unsigned long in_offset;
	298	unsigned long in_page_bytes_left;
	299	unsigned long tot_in;
	300	unsigned long tot_out;
	301	unsigned long tot_len;
	302	char *buf;
ca9b688c	303	bool may_late_unmap, need_unmap;
e1ddce71 AJ	304	struct page **pages_in = cb->compressed_pages;
	305	u64 disk_start = cb->start;
	306	struct bio *orig_bio = cb->orig_bio;
a6fa6fae LZ	307
	308	data_in = kmap(pages_in[0]);
	309	tot_len = read_compress_length(data_in);
314bfa47 QW	310	/*
	311	* Compressed data header check.
	312	*
	313	* The real compressed size can't exceed the maximum extent length, and
	314	* all pages should be used (whole unused page with just the segment
	315	* header is not possible). If this happens it means the compressed
	316	* extent is corrupted.
	317	*/
	318	if (tot_len > min_t(size_t, BTRFS_MAX_COMPRESSED, srclen) \|\|
	319	tot_len < srclen - PAGE_SIZE) {
	320	ret = -EUCLEAN;
	321	goto done;
	322	}
a6fa6fae LZ	323
	324	tot_in = LZO_LEN;
	325	in_offset = LZO_LEN;
09cbfeaf	326	in_page_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	327
a6fa6fae LZ	328	tot_out = 0;
a6fa6fae LZ	329
	330	while (tot_in < tot_len) {
	331	in_len = read_compress_length(data_in + in_offset);
	332	in_page_bytes_left -= LZO_LEN;
	333	in_offset += LZO_LEN;
	334	tot_in += LZO_LEN;
	335
314bfa47 QW	336	/*
	337	* Segment header check.
	338	*
	339	* The segment length must not exceed the maximum LZO
	340	* compression size, nor the total compressed size.
	341	*/
	342	if (in_len > max_segment_len \|\| tot_in + in_len > tot_len) {
	343	ret = -EUCLEAN;
	344	goto done;
	345	}
	346
a6fa6fae LZ	347	tot_in += in_len;
a6fa6fae LZ	348	working_bytes = in_len;
ca9b688c	349	may_late_unmap = need_unmap = false;
a6fa6fae LZ	350
	351	/* fast path: avoid using the working buffer */
	352	if (in_page_bytes_left >= in_len) {
	353	buf = data_in + in_offset;
	354	bytes = in_len;
ca9b688c	355	may_late_unmap = true;
a6fa6fae LZ	356	goto cont;
	357	}
	358
	359	/* copy bytes from the pages into the working buffer */
	360	buf = workspace->cbuf;
	361	buf_offset = 0;
	362	while (working_bytes) {
	363	bytes = min(working_bytes, in_page_bytes_left);
	364
	365	memcpy(buf + buf_offset, data_in + in_offset, bytes);
	366	buf_offset += bytes;
	367	cont:
	368	working_bytes -= bytes;
	369	in_page_bytes_left -= bytes;
	370	in_offset += bytes;
	371
	372	/* check if we need to pick another page */
	373	if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
	374	\|\| in_page_bytes_left == 0) {
	375	tot_in += in_page_bytes_left;
	376
	377	if (working_bytes == 0 && tot_in >= tot_len)
	378	break;
	379
ca9b688c	380	if (page_in_index + 1 >= total_pages_in) {
60e1975a	381	ret = -EIO;
a6fa6fae LZ	382	goto done;
a6fa6fae LZ	383	}
ca9b688c LZ	384
	385	if (may_late_unmap)
	386	need_unmap = true;
	387	else
	388	kunmap(pages_in[page_in_index]);
	389
	390	data_in = kmap(pages_in[++page_in_index]);
a6fa6fae	391
09cbfeaf	392	in_page_bytes_left = PAGE_SIZE;
a6fa6fae LZ	393	in_offset = 0;
	394	}
	395	}
	396
314bfa47	397	out_len = max_segment_len;
a6fa6fae LZ	398	ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
a6fa6fae LZ	399	&out_len);
ca9b688c LZ	400	if (need_unmap)
ca9b688c LZ	401	kunmap(pages_in[page_in_index - 1]);
a6fa6fae	402	if (ret != LZO_E_OK) {
62e85577	403	pr_warn("BTRFS: decompress failed\n");
60e1975a	404	ret = -EIO;
a6fa6fae LZ	405	break;
	406	}
	407
a6fa6fae	408	buf_start = tot_out;
a6fa6fae LZ	409	tot_out += out_len;
a6fa6fae LZ	410
3a39c18d	411	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
974b1adc	412	tot_out, disk_start, orig_bio);
3a39c18d	413	if (ret2 == 0)
a6fa6fae	414	break;
a6fa6fae LZ	415	}
a6fa6fae LZ	416	done:
ca9b688c	417	kunmap(pages_in[page_in_index]);
2f19cad9	418	if (!ret)
974b1adc	419	zero_fill_bio(orig_bio);
a6fa6fae LZ	420	return ret;
	421	}
	422
c4bf665a DS	423	int lzo_decompress(struct list_head ws, unsigned char data_in,
	424	struct page *dest_page, unsigned long start_byte, size_t srclen,
	425	size_t destlen)
a6fa6fae LZ	426	{
	427	struct workspace *workspace = list_entry(ws, struct workspace, list);
	428	size_t in_len;
	429	size_t out_len;
de885e3e	430	size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	431	int ret = 0;
	432	char *kaddr;
	433	unsigned long bytes;
	434
de885e3e QW	435	if (srclen < LZO_LEN \|\| srclen > max_segment_len + LZO_LEN * 2)
de885e3e QW	436	return -EUCLEAN;
a6fa6fae	437
de885e3e QW	438	in_len = read_compress_length(data_in);
	439	if (in_len != srclen)
	440	return -EUCLEAN;
a6fa6fae LZ	441	data_in += LZO_LEN;
	442
	443	in_len = read_compress_length(data_in);
de885e3e QW	444	if (in_len != srclen - LZO_LEN * 2) {
	445	ret = -EUCLEAN;
	446	goto out;
	447	}
a6fa6fae LZ	448	data_in += LZO_LEN;
a6fa6fae LZ	449
09cbfeaf	450	out_len = PAGE_SIZE;
a6fa6fae LZ	451	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
a6fa6fae LZ	452	if (ret != LZO_E_OK) {
62e85577	453	pr_warn("BTRFS: decompress failed!\n");
60e1975a	454	ret = -EIO;
a6fa6fae LZ	455	goto out;
	456	}
	457
	458	if (out_len < start_byte) {
60e1975a	459	ret = -EIO;
a6fa6fae LZ	460	goto out;
	461	}
	462
2f19cad9 CM	463	/*
	464	* the caller is already checking against PAGE_SIZE, but lets
	465	* move this check closer to the memcpy/memset
	466	*/
	467	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
a6fa6fae LZ	468	bytes = min_t(unsigned long, destlen, out_len - start_byte);
a6fa6fae LZ	469
7ac687d9	470	kaddr = kmap_atomic(dest_page);
a6fa6fae	471	memcpy(kaddr, workspace->buf + start_byte, bytes);
2f19cad9 CM	472
	473	/*
	474	* btrfs_getblock is doing a zero on the tail of the page too,
	475	* but this will cover anything missing from the decompressed
	476	* data.
	477	*/
	478	if (bytes < destlen)
	479	memset(kaddr+bytes, 0, destlen-bytes);
7ac687d9	480	kunmap_atomic(kaddr);
a6fa6fae LZ	481	out:
	482	return ret;
	483	}
	484
e8c9f186	485	const struct btrfs_compress_op btrfs_lzo_compress = {
be951045	486	.workspace_manager = &wsm,
e18333a7 DS	487	.max_level = 1,
e18333a7 DS	488	.default_level = 1,
a6fa6fae	489	};