// 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 "messages.h"
#include "compression.h"
#include "ctree.h"
#include "super.h"
#include "btrfs_inode.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 sector 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 sector boundary, thus it's possible to
* have at most 3 padding zeros at the end of the sector.
*
* 2.2 Data Payload
* Variable size. Size up limit should be lzo1x_worst_compress(sectorsize)
* which is 4419 for a 4KiB sectorsize.
*
* Example with 4K sectorsize:
* 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 ... |
*/
#define WORKSPACE_BUF_LENGTH (lzo1x_worst_compress(PAGE_SIZE))
#define WORKSPACE_CBUF_LENGTH (lzo1x_worst_compress(PAGE_SIZE))
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 | __GFP_NOWARN);
workspace->buf = kvmalloc(WORKSPACE_BUF_LENGTH, GFP_KERNEL | __GFP_NOWARN);
workspace->cbuf = kvmalloc(WORKSPACE_CBUF_LENGTH, GFP_KERNEL | __GFP_NOWARN);
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);
}
/*
* Will do:
*
* - Write a segment header into the destination
* - Copy the compressed buffer into the destination
* - Make sure we have enough space in the last sector to fit a segment header
* If not, we will pad at most (LZO_LEN (4)) - 1 bytes of zeros.
*
* Will allocate new pages when needed.
*/
static int copy_compressed_data_to_page(char *compressed_data,
size_t compressed_size,
struct folio **out_folios,
unsigned long max_nr_folio,
u32 *cur_out,
const u32 sectorsize)
{
u32 sector_bytes_left;
u32 orig_out;
struct folio *cur_folio;
char *kaddr;
if ((*cur_out / PAGE_SIZE) >= max_nr_folio)
return -E2BIG;
/*
* We never allow a segment header crossing sector boundary, previous
* run should ensure we have enough space left inside the sector.
*/
ASSERT((*cur_out / sectorsize) == (*cur_out + LZO_LEN - 1) / sectorsize);
cur_folio = out_folios[*cur_out / PAGE_SIZE];
/* Allocate a new page */
if (!cur_folio) {
cur_folio = btrfs_alloc_compr_folio();
if (!cur_folio)
return -ENOMEM;
out_folios[*cur_out / PAGE_SIZE] = cur_folio;
}
kaddr = kmap_local_folio(cur_folio, 0);
write_compress_length(kaddr + offset_in_page(*cur_out),
compressed_size);
*cur_out += LZO_LEN;
orig_out = *cur_out;
/* Copy compressed data */
while (*cur_out - orig_out < compressed_size) {
u32 copy_len = min_t(u32, sectorsize - *cur_out % sectorsize,
orig_out + compressed_size - *cur_out);
kunmap_local(kaddr);
if ((*cur_out / PAGE_SIZE) >= max_nr_folio)
return -E2BIG;
cur_folio = out_folios[*cur_out / PAGE_SIZE];
/* Allocate a new page */
if (!cur_folio) {
cur_folio = btrfs_alloc_compr_folio();
if (!cur_folio)
return -ENOMEM;
out_folios[*cur_out / PAGE_SIZE] = cur_folio;
}
kaddr = kmap_local_folio(cur_folio, 0);
memcpy(kaddr + offset_in_page(*cur_out),
compressed_data + *cur_out - orig_out, copy_len);
*cur_out += copy_len;
}
/*
* Check if we can fit the next segment header into the remaining space
* of the sector.
*/
sector_bytes_left = round_up(*cur_out, sectorsize) - *cur_out;
if (sector_bytes_left >= LZO_LEN || sector_bytes_left == 0)
goto out;
/* The remaining size is not enough, pad it with zeros */
memset(kaddr + offset_in_page(*cur_out), 0,
sector_bytes_left);
*cur_out += sector_bytes_left;
out:
kunmap_local(kaddr);
return 0;
}
int lzo_compress_folios(struct list_head *ws, struct address_space *mapping,
u64 start, struct folio **folios, unsigned long *out_folios,
unsigned long *total_in, unsigned long *total_out)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
const u32 sectorsize = inode_to_fs_info(mapping->host)->sectorsize;
struct folio *folio_in = NULL;
char *sizes_ptr;
const unsigned long max_nr_folio = *out_folios;
int ret = 0;
/* Points to the file offset of input data */
u64 cur_in = start;
/* Points to the current output byte */
u32 cur_out = 0;
u32 len = *total_out;
ASSERT(max_nr_folio > 0);
*out_folios = 0;
*total_out = 0;
*total_in = 0;
/*
* Skip the header for now, we will later come back and write the total
* compressed size
*/
cur_out += LZO_LEN;
while (cur_in < start + len) {
char *data_in;
const u32 sectorsize_mask = sectorsize - 1;
u32 sector_off = (cur_in - start) & sectorsize_mask;
u32 in_len;
size_t out_len;
/* Get the input page first */
if (!folio_in) {
ret = btrfs_compress_filemap_get_folio(mapping, cur_in, &folio_in);
if (ret < 0)
goto out;
}
/* Compress at most one sector of data each time */
in_len = min_t(u32, start + len - cur_in, sectorsize - sector_off);
ASSERT(in_len);
data_in = kmap_local_folio(folio_in, 0);
ret = lzo1x_1_compress(data_in +
offset_in_page(cur_in), in_len,
workspace->cbuf, &out_len,
workspace->mem);
kunmap_local(data_in);
if (unlikely(ret < 0)) {
/* lzo1x_1_compress never fails. */
ret = -EIO;
goto out;
}
ret = copy_compressed_data_to_page(workspace->cbuf, out_len,
folios, max_nr_folio,
&cur_out, sectorsize);
if (ret < 0)
goto out;
cur_in += in_len;
/*
* Check if we're making it bigger after two sectors. And if
* it is so, give up.
*/
if (cur_in - start > sectorsize * 2 && cur_in - start < cur_out) {
ret = -E2BIG;
goto out;
}
/* Check if we have reached page boundary */
if (PAGE_ALIGNED(cur_in)) {
folio_put(folio_in);
folio_in = NULL;
}
}
/* Store the size of all chunks of compressed data */
sizes_ptr = kmap_local_folio(folios[0], 0);
write_compress_length(sizes_ptr, cur_out);
kunmap_local(sizes_ptr);
ret = 0;
*total_out = cur_out;
*total_in = cur_in - start;
out:
if (folio_in)
folio_put(folio_in);
*out_folios = DIV_ROUND_UP(cur_out, PAGE_SIZE);
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 folio *cur_folio;
u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in),
orig_in + len - *cur_in);
ASSERT(copy_len);
cur_folio = cb->compressed_folios[*cur_in / PAGE_SIZE];
memcpy_from_folio(dest + *cur_in - orig_in, cur_folio,
offset_in_folio(cur_folio, *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 = cb->bbio.inode->root->fs_info;
const u32 sectorsize = fs_info->sectorsize;
char *kaddr;
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;
kaddr = kmap_local_folio(cb->compressed_folios[0], 0);
len_in = read_compress_length(kaddr);
kunmap_local(kaddr);
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 (unlikely(len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) ||
round_up(len_in, sectorsize) < cb->compressed_len)) {
struct btrfs_inode *inode = cb->bbio.inode;
btrfs_err(fs_info,
"lzo header invalid, root %llu inode %llu offset %llu lzo len %u compressed len %u",
btrfs_root_id(inode->root), btrfs_ino(inode),
cb->start, len_in, cb->compressed_len);
return -EUCLEAN;
}
/* Go through each lzo segment */
while (cur_in < len_in) {
struct folio *cur_folio;
/* 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_folio = cb->compressed_folios[cur_in / PAGE_SIZE];
ASSERT(cur_folio);
kaddr = kmap_local_folio(cur_folio, 0);
seg_len = read_compress_length(kaddr + offset_in_page(cur_in));
kunmap_local(kaddr);
cur_in += LZO_LEN;
if (unlikely(seg_len > WORKSPACE_CBUF_LENGTH)) {
struct btrfs_inode *inode = cb->bbio.inode;
/*
* seg_len shouldn't be larger than we have allocated
* for workspace->cbuf
*/
btrfs_err(fs_info,
"lzo segment too big, root %llu inode %llu offset %llu len %u",
btrfs_root_id(inode->root), btrfs_ino(inode),
cb->start, seg_len);
return -EIO;
}
/* 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 (unlikely(ret != LZO_E_OK)) {
struct btrfs_inode *inode = cb->bbio.inode;
btrfs_err(fs_info,
"lzo decompression failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode),
cb->start);
return -EIO;
}
/* 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)
return 0;
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;
}
return 0;
}
int lzo_decompress(struct list_head *ws, const u8 *data_in,
struct folio *dest_folio, unsigned long dest_pgoff, size_t srclen,
size_t destlen)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
struct btrfs_fs_info *fs_info = folio_to_fs_info(dest_folio);
const u32 sectorsize = fs_info->sectorsize;
size_t in_len;
size_t out_len;
size_t max_segment_len = WORKSPACE_BUF_LENGTH;
int ret = 0;
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 = sectorsize;
ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
if (unlikely(ret != LZO_E_OK)) {
struct btrfs_inode *inode = folio_to_inode(dest_folio);
btrfs_err(fs_info,
"lzo decompression failed, error %d root %llu inode %llu offset %llu",
ret, btrfs_root_id(inode->root), btrfs_ino(inode),
folio_pos(dest_folio));
ret = -EIO;
goto out;
}
ASSERT(out_len <= sectorsize);
memcpy_to_folio(dest_folio, dest_pgoff, workspace->buf, out_len);
/* Early end, considered as an error. */
if (unlikely(out_len < destlen)) {
ret = -EIO;
folio_zero_range(dest_folio, dest_pgoff + out_len, destlen - out_len);
}
out:
return ret;
}
const struct btrfs_compress_op btrfs_lzo_compress = {
.workspace_manager = &wsm,
.max_level = 1,
.default_level = 1,
};
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