[linux-2.6-block.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_put_workspace(struct list_head *ws)
{
	btrfs_put_workspace(&wsm, ws);
}

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,
	.put_workspace		= lzo_put_workspace,
	.alloc_workspace	= lzo_alloc_workspace,
	.free_workspace		= lzo_free_workspace,
	.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_put_workspace(struct list_head *ws)
92ee5530 DZ	67	{
	68	btrfs_put_workspace(&wsm, ws);
	69	}
	70
d20f395f	71	void lzo_free_workspace(struct list_head *ws)
a6fa6fae LZ	72	{
	73	struct workspace *workspace = list_entry(ws, struct workspace, list);
	74
6acafd1e DS	75	kvfree(workspace->buf);
	76	kvfree(workspace->cbuf);
	77	kvfree(workspace->mem);
a6fa6fae LZ	78	kfree(workspace);
	79	}
	80
d20f395f	81	struct list_head *lzo_alloc_workspace(unsigned int level)
a6fa6fae LZ	82	{
	83	struct workspace *workspace;
	84
389a6cfc	85	workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
a6fa6fae LZ	86	if (!workspace)
	87	return ERR_PTR(-ENOMEM);
	88
6acafd1e DS	89	workspace->mem = kvmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
	90	workspace->buf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
	91	workspace->cbuf = kvmalloc(lzo1x_worst_compress(PAGE_SIZE), GFP_KERNEL);
a6fa6fae LZ	92	if (!workspace->mem \|\| !workspace->buf \|\| !workspace->cbuf)
	93	goto fail;
	94
	95	INIT_LIST_HEAD(&workspace->list);
	96
	97	return &workspace->list;
	98	fail:
	99	lzo_free_workspace(&workspace->list);
	100	return ERR_PTR(-ENOMEM);
	101	}
	102
	103	static inline void write_compress_length(char *buf, size_t len)
	104	{
	105	__le32 dlen;
	106
	107	dlen = cpu_to_le32(len);
	108	memcpy(buf, &dlen, LZO_LEN);
	109	}
	110
14a3357b	111	static inline size_t read_compress_length(const char *buf)
a6fa6fae LZ	112	{
	113	__le32 dlen;
	114
	115	memcpy(&dlen, buf, LZO_LEN);
	116	return le32_to_cpu(dlen);
	117	}
	118
c4bf665a DS	119	int lzo_compress_pages(struct list_head ws, struct address_space mapping,
	120	u64 start, struct page *pages, unsigned long out_pages,
	121	unsigned long total_in, unsigned long total_out)
a6fa6fae LZ	122	{
	123	struct workspace *workspace = list_entry(ws, struct workspace, list);
	124	int ret = 0;
	125	char *data_in;
	126	char *cpage_out;
	127	int nr_pages = 0;
	128	struct page *in_page = NULL;
	129	struct page *out_page = NULL;
	130	unsigned long bytes_left;
38c31464	131	unsigned long len = *total_out;
4d3a800e	132	unsigned long nr_dest_pages = *out_pages;
e5d74902	133	const unsigned long max_out = nr_dest_pages * PAGE_SIZE;
a6fa6fae LZ	134	size_t in_len;
	135	size_t out_len;
	136	char *buf;
	137	unsigned long tot_in = 0;
	138	unsigned long tot_out = 0;
	139	unsigned long pg_bytes_left;
	140	unsigned long out_offset;
	141	unsigned long bytes;
	142
	143	*out_pages = 0;
	144	*total_out = 0;
	145	*total_in = 0;
	146
09cbfeaf	147	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
a6fa6fae LZ	148	data_in = kmap(in_page);
	149
	150	/*
	151	* store the size of all chunks of compressed data in
	152	* the first 4 bytes
	153	*/
	154	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	155	if (out_page == NULL) {
	156	ret = -ENOMEM;
	157	goto out;
	158	}
	159	cpage_out = kmap(out_page);
	160	out_offset = LZO_LEN;
	161	tot_out = LZO_LEN;
	162	pages[0] = out_page;
	163	nr_pages = 1;
09cbfeaf	164	pg_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	165
a6fa6fae LZ	166	/* compress at most one page of data each time */
09cbfeaf	167	in_len = min(len, PAGE_SIZE);
a6fa6fae LZ	168	while (tot_in < len) {
	169	ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
	170	&out_len, workspace->mem);
	171	if (ret != LZO_E_OK) {
036b0217	172	pr_debug("BTRFS: lzo in loop returned %d\n",
a6fa6fae	173	ret);
60e1975a	174	ret = -EIO;
a6fa6fae LZ	175	goto out;
	176	}
	177
	178	/* store the size of this chunk of compressed data */
	179	write_compress_length(cpage_out + out_offset, out_len);
	180	tot_out += LZO_LEN;
	181	out_offset += LZO_LEN;
	182	pg_bytes_left -= LZO_LEN;
	183
	184	tot_in += in_len;
	185	tot_out += out_len;
	186
	187	/* copy bytes from the working buffer into the pages */
	188	buf = workspace->cbuf;
	189	while (out_len) {
	190	bytes = min_t(unsigned long, pg_bytes_left, out_len);
	191
	192	memcpy(cpage_out + out_offset, buf, bytes);
	193
	194	out_len -= bytes;
	195	pg_bytes_left -= bytes;
	196	buf += bytes;
	197	out_offset += bytes;
	198
	199	/*
	200	* we need another page for writing out.
	201	*
	202	* Note if there's less than 4 bytes left, we just
	203	* skip to a new page.
	204	*/
	205	if ((out_len == 0 && pg_bytes_left < LZO_LEN) \|\|
	206	pg_bytes_left == 0) {
	207	if (pg_bytes_left) {
	208	memset(cpage_out + out_offset, 0,
	209	pg_bytes_left);
	210	tot_out += pg_bytes_left;
	211	}
	212
	213	/* we're done, don't allocate new page */
	214	if (out_len == 0 && tot_in >= len)
	215	break;
	216
	217	kunmap(out_page);
	218	if (nr_pages == nr_dest_pages) {
	219	out_page = NULL;
60e1975a	220	ret = -E2BIG;
a6fa6fae LZ	221	goto out;
	222	}
	223
	224	out_page = alloc_page(GFP_NOFS \| __GFP_HIGHMEM);
	225	if (out_page == NULL) {
	226	ret = -ENOMEM;
	227	goto out;
	228	}
	229	cpage_out = kmap(out_page);
	230	pages[nr_pages++] = out_page;
	231
09cbfeaf	232	pg_bytes_left = PAGE_SIZE;
a6fa6fae LZ	233	out_offset = 0;
	234	}
	235	}
	236
	237	/* we're making it bigger, give up */
59516f60	238	if (tot_in > 8192 && tot_in < tot_out) {
60e1975a	239	ret = -E2BIG;
a6fa6fae	240	goto out;
59516f60	241	}
a6fa6fae LZ	242
	243	/* we're all done */
	244	if (tot_in >= len)
	245	break;
	246
	247	if (tot_out > max_out)
	248	break;
	249
	250	bytes_left = len - tot_in;
	251	kunmap(in_page);
09cbfeaf	252	put_page(in_page);
a6fa6fae	253
09cbfeaf KS	254	start += PAGE_SIZE;
09cbfeaf KS	255	in_page = find_get_page(mapping, start >> PAGE_SHIFT);
a6fa6fae	256	data_in = kmap(in_page);
09cbfeaf	257	in_len = min(bytes_left, PAGE_SIZE);
a6fa6fae LZ	258	}
a6fa6fae LZ	259
1e9d7291 TT	260	if (tot_out >= tot_in) {
1e9d7291 TT	261	ret = -E2BIG;
a6fa6fae	262	goto out;
1e9d7291	263	}
a6fa6fae LZ	264
	265	/* store the size of all chunks of compressed data */
	266	cpage_out = kmap(pages[0]);
	267	write_compress_length(cpage_out, tot_out);
	268
	269	kunmap(pages[0]);
	270
	271	ret = 0;
	272	*total_out = tot_out;
	273	*total_in = tot_in;
	274	out:
	275	*out_pages = nr_pages;
	276	if (out_page)
	277	kunmap(out_page);
	278
	279	if (in_page) {
	280	kunmap(in_page);
09cbfeaf	281	put_page(in_page);
a6fa6fae LZ	282	}
	283
	284	return ret;
	285	}
	286
c4bf665a	287	int lzo_decompress_bio(struct list_head ws, struct compressed_bio cb)
a6fa6fae LZ	288	{
a6fa6fae LZ	289	struct workspace *workspace = list_entry(ws, struct workspace, list);
3a39c18d	290	int ret = 0, ret2;
a6fa6fae	291	char *data_in;
a6fa6fae	292	unsigned long page_in_index = 0;
e1ddce71	293	size_t srclen = cb->compressed_len;
09cbfeaf	294	unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
a6fa6fae LZ	295	unsigned long buf_start;
	296	unsigned long buf_offset = 0;
	297	unsigned long bytes;
	298	unsigned long working_bytes;
a6fa6fae LZ	299	size_t in_len;
a6fa6fae LZ	300	size_t out_len;
314bfa47	301	const size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	302	unsigned long in_offset;
	303	unsigned long in_page_bytes_left;
	304	unsigned long tot_in;
	305	unsigned long tot_out;
	306	unsigned long tot_len;
	307	char *buf;
ca9b688c	308	bool may_late_unmap, need_unmap;
e1ddce71 AJ	309	struct page **pages_in = cb->compressed_pages;
	310	u64 disk_start = cb->start;
	311	struct bio *orig_bio = cb->orig_bio;
a6fa6fae LZ	312
	313	data_in = kmap(pages_in[0]);
	314	tot_len = read_compress_length(data_in);
314bfa47 QW	315	/*
	316	* Compressed data header check.
	317	*
	318	* The real compressed size can't exceed the maximum extent length, and
	319	* all pages should be used (whole unused page with just the segment
	320	* header is not possible). If this happens it means the compressed
	321	* extent is corrupted.
	322	*/
	323	if (tot_len > min_t(size_t, BTRFS_MAX_COMPRESSED, srclen) \|\|
	324	tot_len < srclen - PAGE_SIZE) {
	325	ret = -EUCLEAN;
	326	goto done;
	327	}
a6fa6fae LZ	328
	329	tot_in = LZO_LEN;
	330	in_offset = LZO_LEN;
09cbfeaf	331	in_page_bytes_left = PAGE_SIZE - LZO_LEN;
a6fa6fae LZ	332
a6fa6fae LZ	333	tot_out = 0;
a6fa6fae LZ	334
	335	while (tot_in < tot_len) {
	336	in_len = read_compress_length(data_in + in_offset);
	337	in_page_bytes_left -= LZO_LEN;
	338	in_offset += LZO_LEN;
	339	tot_in += LZO_LEN;
	340
314bfa47 QW	341	/*
	342	* Segment header check.
	343	*
	344	* The segment length must not exceed the maximum LZO
	345	* compression size, nor the total compressed size.
	346	*/
	347	if (in_len > max_segment_len \|\| tot_in + in_len > tot_len) {
	348	ret = -EUCLEAN;
	349	goto done;
	350	}
	351
a6fa6fae LZ	352	tot_in += in_len;
a6fa6fae LZ	353	working_bytes = in_len;
ca9b688c	354	may_late_unmap = need_unmap = false;
a6fa6fae LZ	355
	356	/* fast path: avoid using the working buffer */
	357	if (in_page_bytes_left >= in_len) {
	358	buf = data_in + in_offset;
	359	bytes = in_len;
ca9b688c	360	may_late_unmap = true;
a6fa6fae LZ	361	goto cont;
	362	}
	363
	364	/* copy bytes from the pages into the working buffer */
	365	buf = workspace->cbuf;
	366	buf_offset = 0;
	367	while (working_bytes) {
	368	bytes = min(working_bytes, in_page_bytes_left);
	369
	370	memcpy(buf + buf_offset, data_in + in_offset, bytes);
	371	buf_offset += bytes;
	372	cont:
	373	working_bytes -= bytes;
	374	in_page_bytes_left -= bytes;
	375	in_offset += bytes;
	376
	377	/* check if we need to pick another page */
	378	if ((working_bytes == 0 && in_page_bytes_left < LZO_LEN)
	379	\|\| in_page_bytes_left == 0) {
	380	tot_in += in_page_bytes_left;
	381
	382	if (working_bytes == 0 && tot_in >= tot_len)
	383	break;
	384
ca9b688c	385	if (page_in_index + 1 >= total_pages_in) {
60e1975a	386	ret = -EIO;
a6fa6fae LZ	387	goto done;
a6fa6fae LZ	388	}
ca9b688c LZ	389
	390	if (may_late_unmap)
	391	need_unmap = true;
	392	else
	393	kunmap(pages_in[page_in_index]);
	394
	395	data_in = kmap(pages_in[++page_in_index]);
a6fa6fae	396
09cbfeaf	397	in_page_bytes_left = PAGE_SIZE;
a6fa6fae LZ	398	in_offset = 0;
	399	}
	400	}
	401
314bfa47	402	out_len = max_segment_len;
a6fa6fae LZ	403	ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
a6fa6fae LZ	404	&out_len);
ca9b688c LZ	405	if (need_unmap)
ca9b688c LZ	406	kunmap(pages_in[page_in_index - 1]);
a6fa6fae	407	if (ret != LZO_E_OK) {
62e85577	408	pr_warn("BTRFS: decompress failed\n");
60e1975a	409	ret = -EIO;
a6fa6fae LZ	410	break;
	411	}
	412
a6fa6fae	413	buf_start = tot_out;
a6fa6fae LZ	414	tot_out += out_len;
a6fa6fae LZ	415
3a39c18d	416	ret2 = btrfs_decompress_buf2page(workspace->buf, buf_start,
974b1adc	417	tot_out, disk_start, orig_bio);
3a39c18d	418	if (ret2 == 0)
a6fa6fae	419	break;
a6fa6fae LZ	420	}
a6fa6fae LZ	421	done:
ca9b688c	422	kunmap(pages_in[page_in_index]);
2f19cad9	423	if (!ret)
974b1adc	424	zero_fill_bio(orig_bio);
a6fa6fae LZ	425	return ret;
	426	}
	427
c4bf665a DS	428	int lzo_decompress(struct list_head ws, unsigned char data_in,
	429	struct page *dest_page, unsigned long start_byte, size_t srclen,
	430	size_t destlen)
a6fa6fae LZ	431	{
	432	struct workspace *workspace = list_entry(ws, struct workspace, list);
	433	size_t in_len;
	434	size_t out_len;
de885e3e	435	size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE);
a6fa6fae LZ	436	int ret = 0;
	437	char *kaddr;
	438	unsigned long bytes;
	439
de885e3e QW	440	if (srclen < LZO_LEN \|\| srclen > max_segment_len + LZO_LEN * 2)
de885e3e QW	441	return -EUCLEAN;
a6fa6fae	442
de885e3e QW	443	in_len = read_compress_length(data_in);
	444	if (in_len != srclen)
	445	return -EUCLEAN;
a6fa6fae LZ	446	data_in += LZO_LEN;
	447
	448	in_len = read_compress_length(data_in);
de885e3e QW	449	if (in_len != srclen - LZO_LEN * 2) {
	450	ret = -EUCLEAN;
	451	goto out;
	452	}
a6fa6fae LZ	453	data_in += LZO_LEN;
a6fa6fae LZ	454
09cbfeaf	455	out_len = PAGE_SIZE;
a6fa6fae LZ	456	ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
a6fa6fae LZ	457	if (ret != LZO_E_OK) {
62e85577	458	pr_warn("BTRFS: decompress failed!\n");
60e1975a	459	ret = -EIO;
a6fa6fae LZ	460	goto out;
	461	}
	462
	463	if (out_len < start_byte) {
60e1975a	464	ret = -EIO;
a6fa6fae LZ	465	goto out;
	466	}
	467
2f19cad9 CM	468	/*
	469	* the caller is already checking against PAGE_SIZE, but lets
	470	* move this check closer to the memcpy/memset
	471	*/
	472	destlen = min_t(unsigned long, destlen, PAGE_SIZE);
a6fa6fae LZ	473	bytes = min_t(unsigned long, destlen, out_len - start_byte);
a6fa6fae LZ	474
7ac687d9	475	kaddr = kmap_atomic(dest_page);
a6fa6fae	476	memcpy(kaddr, workspace->buf + start_byte, bytes);
2f19cad9 CM	477
	478	/*
	479	* btrfs_getblock is doing a zero on the tail of the page too,
	480	* but this will cover anything missing from the decompressed
	481	* data.
	482	*/
	483	if (bytes < destlen)
	484	memset(kaddr+bytes, 0, destlen-bytes);
7ac687d9	485	kunmap_atomic(kaddr);
a6fa6fae LZ	486	out:
	487	return ret;
	488	}
	489
e8c9f186	490	const struct btrfs_compress_op btrfs_lzo_compress = {
be951045	491	.workspace_manager = &wsm,
92ee5530	492	.put_workspace = lzo_put_workspace,
a6fa6fae LZ	493	.alloc_workspace = lzo_alloc_workspace,
a6fa6fae LZ	494	.free_workspace = lzo_free_workspace,
e18333a7 DS	495	.max_level = 1,
e18333a7 DS	496	.default_level = 1,
a6fa6fae	497	};