[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, followd 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 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);
}

static struct list_head *lzo_alloc_workspace(void)
{
	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);
}

static 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;
}

static 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;
}

static 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;
}

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

const struct btrfs_compress_op btrfs_lzo_compress = {
	.alloc_workspace	= lzo_alloc_workspace,
	.free_workspace		= lzo_free_workspace,
	.compress_pages		= lzo_compress_pages,
	.decompress_bio		= lzo_decompress_bio,
	.decompress		= lzo_decompress,
	.set_level		= lzo_set_level,
};
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)
	30	* Variable size. Each segment includes one segment header, followd by data
	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
	64	static void lzo_free_workspace(struct list_head *ws)
	65	{
	66	struct workspace *workspace = list_entry(ws, struct workspace, list);
	67
6acafd1e DS	68	kvfree(workspace->buf);
	69	kvfree(workspace->cbuf);
	70	kvfree(workspace->mem);
a6fa6fae LZ	71	kfree(workspace);
	72	}
	73
	74	static struct list_head *lzo_alloc_workspace(void)
	75	{
	76	struct workspace *workspace;
	77
389a6cfc	78	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
a6fa6fae LZ	79	if (!workspace)
	80	return ERR_PTR(-ENOMEM);
	81
6acafd1e DS	82	workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
	83	workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
	84	workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
a6fa6fae LZ	85	if (!workspace->mem \|\| !workspace->buf \|\| !workspace->cbuf)
	86	goto fail;
	87
	88	INIT_LIST_HEAD(&workspace->list);
	89
	90	return &workspace->list;
	91	fail:
	92	lzo_free_workspace(&workspace->list);
	93	return ERR_PTR(-ENOMEM);
	94	}
	95
	96	static inline void write_compress_length(char *buf, size_t len)
	97	{
	98	__le32 dlen;
	99
	100	dlen = cpu_to_le32(len);
	101	memcpy(buf, &dlen, LZO_LEN);
	102	}
	103
14a3357b	104	static inline size_t read_compress_length(const char *buf)
a6fa6fae LZ	105	{
	106	__le32 dlen;
	107
	108	memcpy(&dlen, buf, LZO_LEN);
	109	return le32_to_cpu(dlen);
	110	}
	111
	112	static int lzo_compress_pages(struct list_head *ws,
	113	struct address_space *mapping,
38c31464	114	u64 start,
a6fa6fae	115	struct page **pages,
a6fa6fae LZ	116	unsigned long *out_pages,
a6fa6fae LZ	117	unsigned long *total_in,
e5d74902	118	unsigned long *total_out)
a6fa6fae LZ	119	{
	120	struct workspace *workspace = list_entry(ws, struct workspace, list);
	121	int ret = 0;
	122	char *data_in;
	123	char *cpage_out;
	124	int nr_pages = 0;
	125	struct page *in_page = NULL;
	126	struct page *out_page = NULL;
	127	unsigned long bytes_left;
38c31464	128	unsigned long len = *total_out;
4d3a800e	129	unsigned long nr_dest_pages = *out_pages;
e5d74902	130	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
a6fa6fae LZ	131	size_t in_len;
	132	size_t out_len;
	133	char *buf;
	134	unsigned long tot_in = 0;
	135	unsigned long tot_out = 0;
	136	unsigned long pg_bytes_left;
	137	unsigned long out_offset;
	138	unsigned long bytes;
	139
	140	*out_pages = 0;
	141	*total_out = 0;
	142	*total_in = 0;
	143
09cbfeaf	144	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
a6fa6fae LZ	145	data_in = kmap(in_page);
	146
	147	/*
	148	* store the size of all chunks of compressed data in
	149	* the first 4 bytes
	150	*/
	151	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	152	if (out_page == NULL) {
	153	ret = -ENOMEM;
	154	goto out;
	155	}
	156	cpage_out = kmap(out_page);
	157	out_offset = LZO_LEN;
	158	tot_out = LZO_LEN;
	159	pages[0] = out_page;
	160	nr_pages = 1;
09cbfeaf	161	pg_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	162
a6fa6fae LZ	163	/* compress at most one page of data each time */
09cbfeaf	164	in_len = min(len, PAGE_SIZE);
a6fa6fae LZ	165	while (tot_in < len) {
	166	ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
	167	&out_len, workspace->mem);
	168	if (ret != LZO_E_OK) {
036b0217	169	pr_debug("BTRFS: lzo in loop returned %d\n",
a6fa6fae	170	ret);
60e1975a	171	ret = -EIO;
a6fa6fae LZ	172	goto out;
	173	}
	174
	175	/* store the size of this chunk of compressed data */
	176	write_compress_length(cpage_out + out_offset, out_len);
	177	tot_out += LZO_LEN;
	178	out_offset += LZO_LEN;
	179	pg_bytes_left -= LZO_LEN;
	180
	181	tot_in += in_len;
	182	tot_out += out_len;
	183
	184	/* copy bytes from the working buffer into the pages */
	185	buf = workspace->cbuf;
	186	while (out_len) {
	187	bytes = min_t(unsigned long, pg_bytes_left, out_len);
	188
	189	memcpy(cpage_out + out_offset, buf, bytes);
	190
	191	out_len -= bytes;
	192	pg_bytes_left -= bytes;
	193	buf += bytes;
	194	out_offset += bytes;
	195
	196	/*
	197	* we need another page for writing out.
	198	*
	199	* Note if there's less than 4 bytes left, we just
	200	* skip to a new page.
	201	*/
	202	if ((out_len == 0 && pg_bytes_left < LZO_LEN) \|\|
	203	pg_bytes_left == 0) {
	204	if (pg_bytes_left) {
	205	memset(cpage_out + out_offset, 0,
	206	pg_bytes_left);
	207	tot_out += pg_bytes_left;
	208	}
	209
	210	/* we're done, don't allocate new page */
	211	if (out_len == 0 && tot_in >= len)
	212	break;
	213
	214	kunmap(out_page);
	215	if (nr_pages == nr_dest_pages) {
	216	out_page = NULL;
60e1975a	217	ret = -E2BIG;
a6fa6fae LZ	218	goto out;
	219	}
	220
	221	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	222	if (out_page == NULL) {
	223	ret = -ENOMEM;
	224	goto out;
	225	}
	226	cpage_out = kmap(out_page);
	227	pages[nr_pages++] = out_page;
	228
09cbfeaf	229	pg_bytes_left = PAGE_SIZE;
a6fa6fae LZ	230	out_offset = 0;
	231	}
	232	}
	233
	234	/* we're making it bigger, give up */
59516f60	235	if (tot_in > 8192 && tot_in < tot_out) {
60e1975a	236	ret = -E2BIG;
a6fa6fae	237	goto out;
59516f60	238	}
a6fa6fae LZ	239
	240	/* we're all done */
	241	if (tot_in >= len)
	242	break;
	243
	244	if (tot_out > max_out)
	245	break;
	246
	247	bytes_left = len - tot_in;
	248	kunmap(in_page);
09cbfeaf	249	put_page(in_page);
a6fa6fae	250
09cbfeaf KS	251	start += PAGE_SIZE;
09cbfeaf KS	252	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
a6fa6fae	253	data_in = kmap(in_page);
09cbfeaf	254	in_len = min(bytes_left, PAGE_SIZE);
a6fa6fae LZ	255	}
a6fa6fae LZ	256
1e9d7291 TT	257	if (tot_out >= tot_in) {
1e9d7291 TT	258	ret = -E2BIG;
a6fa6fae	259	goto out;
1e9d7291	260	}
a6fa6fae LZ	261
	262	/* store the size of all chunks of compressed data */
	263	cpage_out = kmap(pages[0]);
	264	write_compress_length(cpage_out, tot_out);
	265
	266	kunmap(pages[0]);
	267
	268	ret = 0;
	269	*total_out = tot_out;
	270	*total_in = tot_in;
	271	out:
	272	*out_pages = nr_pages;
	273	if (out_page)
	274	kunmap(out_page);
	275
	276	if (in_page) {
	277	kunmap(in_page);
09cbfeaf	278	put_page(in_page);
a6fa6fae LZ	279	}
	280
	281	return ret;
	282	}
	283
e1ddce71	284	static int lzo_decompress_bio(struct list_head ws, struct compressed_bio cb)
a6fa6fae LZ	285	{
a6fa6fae LZ	286	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	287	int ret = 0, ret2;
a6fa6fae	288	char *data_in;
a6fa6fae	289	unsigned long page_in_index = 0;
e1ddce71	290	size_t srclen = cb->compressed_len;
09cbfeaf	291	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
a6fa6fae LZ	292	unsigned long buf_start;
	293	unsigned long buf_offset = 0;
	294	unsigned long bytes;
	295	unsigned long working_bytes;
a6fa6fae LZ	296	size_t in_len;
a6fa6fae LZ	297	size_t out_len;
314bfa47	298	const size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	299	unsigned long in_offset;
	300	unsigned long in_page_bytes_left;
	301	unsigned long tot_in;
	302	unsigned long tot_out;
	303	unsigned long tot_len;
	304	char *buf;
ca9b688c	305	bool may_late_unmap, need_unmap;
e1ddce71 AJ	306	struct page **pages_in = cb->compressed_pages;
	307	u64 disk_start = cb->start;
	308	struct bio *orig_bio = cb->orig_bio;
a6fa6fae LZ	309
	310	data_in = kmap(pages_in[0]);
	311	tot_len = read_compress_length(data_in);
314bfa47 QW	312	/*
	313	* Compressed data header check.
	314	*
	315	* The real compressed size can't exceed the maximum extent length, and
	316	* all pages should be used (whole unused page with just the segment
	317	* header is not possible). If this happens it means the compressed
	318	* extent is corrupted.
	319	*/
	320	if (tot_len > min_t(size_t, BTRFS_MAX_COMPRESSED, srclen) \|\|
	321	tot_len < srclen - PAGE_SIZE) {
	322	ret = -EUCLEAN;
	323	goto done;
	324	}
a6fa6fae LZ	325
	326	tot_in = LZO_LEN;
	327	in_offset = LZO_LEN;
09cbfeaf	328	in_page_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	329
a6fa6fae LZ	330	tot_out = 0;
a6fa6fae LZ	331
	332	while (tot_in < tot_len) {
	333	in_len = read_compress_length(data_in + in_offset);
	334	in_page_bytes_left -= LZO_LEN;
	335	in_offset += LZO_LEN;
	336	tot_in += LZO_LEN;
	337
314bfa47 QW	338	/*
	339	* Segment header check.
	340	*
	341	* The segment length must not exceed the maximum LZO
	342	* compression size, nor the total compressed size.
	343	*/
	344	if (in_len > max_segment_len \|\| tot_in + in_len > tot_len) {
	345	ret = -EUCLEAN;
	346	goto done;
	347	}
	348
a6fa6fae LZ	349	tot_in += in_len;
a6fa6fae LZ	350	working_bytes = in_len;
ca9b688c	351	may_late_unmap = need_unmap = false;
a6fa6fae LZ	352
	353	/* fast path: avoid using the working buffer */
	354	if (in_page_bytes_left >= in_len) {
	355	buf = data_in + in_offset;
	356	bytes = in_len;
ca9b688c	357	may_late_unmap = true;
a6fa6fae LZ	358	goto cont;
	359	}
	360
	361	/* copy bytes from the pages into the working buffer */
	362	buf = workspace->cbuf;
	363	buf_offset = 0;
	364	while (working_bytes) {
	365	bytes = min(working_bytes, in_page_bytes_left);
	366
	367	memcpy(buf + buf_offset, data_in + in_offset, bytes);
	368	buf_offset += bytes;
	369	cont:
	370	working_bytes -= bytes;
	371	in_page_bytes_left -= bytes;
	372	in_offset += bytes;
	373
	374	/* check if we need to pick another page */
	375	if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
	376	\|\| in_page_bytes_left == 0) {
	377	tot_in += in_page_bytes_left;
	378
	379	if (working_bytes == 0 && tot_in >= tot_len)
	380	break;
	381
ca9b688c	382	if (page_in_index + 1 >= total_pages_in) {
60e1975a	383	ret = -EIO;
a6fa6fae LZ	384	goto done;
a6fa6fae LZ	385	}
ca9b688c LZ	386
	387	if (may_late_unmap)
	388	need_unmap = true;
	389	else
	390	kunmap(pages_in[page_in_index]);
	391
	392	data_in = kmap(pages_in[++page_in_index]);
a6fa6fae	393
09cbfeaf	394	in_page_bytes_left = PAGE_SIZE;
a6fa6fae LZ	395	in_offset = 0;
	396	}
	397	}
	398
314bfa47	399	out_len = max_segment_len;
a6fa6fae LZ	400	ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
a6fa6fae LZ	401	&out_len);
ca9b688c LZ	402	if (need_unmap)
ca9b688c LZ	403	kunmap(pages_in[page_in_index - 1]);
a6fa6fae	404	if (ret != LZO_E_OK) {
62e85577	405	pr_warn("BTRFS: decompress failed\n");
60e1975a	406	ret = -EIO;
a6fa6fae LZ	407	break;
	408	}
	409
a6fa6fae	410	buf_start = tot_out;
a6fa6fae LZ	411	tot_out += out_len;
a6fa6fae LZ	412
3a39c18d	413	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
974b1adc	414	tot_out, disk_start, orig_bio);
3a39c18d	415	if (ret2 == 0)
a6fa6fae	416	break;
a6fa6fae LZ	417	}
a6fa6fae LZ	418	done:
ca9b688c	419	kunmap(pages_in[page_in_index]);
2f19cad9	420	if (!ret)
974b1adc	421	zero_fill_bio(orig_bio);
a6fa6fae LZ	422	return ret;
	423	}
	424
	425	static int lzo_decompress(struct list_head ws, unsigned char data_in,
	426	struct page *dest_page,
	427	unsigned long start_byte,
	428	size_t srclen, size_t destlen)
	429	{
	430	struct workspace *workspace = list_entry(ws, struct workspace, list);
	431	size_t in_len;
	432	size_t out_len;
de885e3e	433	size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	434	int ret = 0;
	435	char *kaddr;
	436	unsigned long bytes;
	437
de885e3e QW	438	if (srclen < LZO_LEN \|\| srclen > max_segment_len + LZO_LEN * 2)
de885e3e QW	439	return -EUCLEAN;
a6fa6fae	440
de885e3e QW	441	in_len = read_compress_length(data_in);
	442	if (in_len != srclen)
	443	return -EUCLEAN;
a6fa6fae LZ	444	data_in += LZO_LEN;
	445
	446	in_len = read_compress_length(data_in);
de885e3e QW	447	if (in_len != srclen - LZO_LEN * 2) {
	448	ret = -EUCLEAN;
	449	goto out;
	450	}
a6fa6fae LZ	451	data_in += LZO_LEN;
a6fa6fae LZ	452
09cbfeaf	453	out_len = PAGE_SIZE;
a6fa6fae LZ	454	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
a6fa6fae LZ	455	if (ret != LZO_E_OK) {
62e85577	456	pr_warn("BTRFS: decompress failed!\n");
60e1975a	457	ret = -EIO;
a6fa6fae LZ	458	goto out;
	459	}
	460
	461	if (out_len < start_byte) {
60e1975a	462	ret = -EIO;
a6fa6fae LZ	463	goto out;
	464	}
	465
2f19cad9 CM	466	/*
	467	* the caller is already checking against PAGE_SIZE, but lets
	468	* move this check closer to the memcpy/memset
	469	*/
	470	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
a6fa6fae LZ	471	bytes = min_t(unsigned long, destlen, out_len - start_byte);
a6fa6fae LZ	472
7ac687d9	473	kaddr = kmap_atomic(dest_page);
a6fa6fae	474	memcpy(kaddr, workspace->buf + start_byte, bytes);
2f19cad9 CM	475
	476	/*
	477	* btrfs_getblock is doing a zero on the tail of the page too,
	478	* but this will cover anything missing from the decompressed
	479	* data.
	480	*/
	481	if (bytes < destlen)
	482	memset(kaddr+bytes, 0, destlen-bytes);
7ac687d9	483	kunmap_atomic(kaddr);
a6fa6fae LZ	484	out:
	485	return ret;
	486	}
	487
f51d2b59 DS	488	static void lzo_set_level(struct list_head *ws, unsigned int type)
	489	{
	490	}
	491
e8c9f186	492	const struct btrfs_compress_op btrfs_lzo_compress = {
a6fa6fae LZ	493	.alloc_workspace = lzo_alloc_workspace,
	494	.free_workspace = lzo_free_workspace,
	495	.compress_pages = lzo_compress_pages,
974b1adc	496	.decompress_bio = lzo_decompress_bio,
a6fa6fae	497	.decompress = lzo_decompress,
f51d2b59	498	.set_level = lzo_set_level,
a6fa6fae	499	};