forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
495 lines
13 KiB
495 lines
13 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Copyright (C) 2008 Oracle. All rights reserved. |
|
*/ |
|
|
|
#include <linux/kernel.h> |
|
#include <linux/slab.h> |
|
#include <linux/mm.h> |
|
#include <linux/init.h> |
|
#include <linux/err.h> |
|
#include <linux/sched.h> |
|
#include <linux/pagemap.h> |
|
#include <linux/bio.h> |
|
#include <linux/lzo.h> |
|
#include <linux/refcount.h> |
|
#include "compression.h" |
|
#include "ctree.h" |
|
|
|
#define LZO_LEN 4 |
|
|
|
/* |
|
* Btrfs LZO compression format |
|
* |
|
* Regular and inlined LZO compressed data extents consist of: |
|
* |
|
* 1. Header |
|
* Fixed size. LZO_LEN (4) bytes long, LE32. |
|
* Records the total size (including the header) of compressed data. |
|
* |
|
* 2. Segment(s) |
|
* Variable size. Each segment includes one segment header, followed by data |
|
* payload. |
|
* One regular LZO compressed extent can have one or more segments. |
|
* For inlined LZO compressed extent, only one segment is allowed. |
|
* One segment represents at most one 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 ... | |
|
*/ |
|
|
|
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); |
|
} |
|
|
|
/* |
|
* 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 page **out_pages, |
|
unsigned long max_nr_page, |
|
u32 *cur_out, |
|
const u32 sectorsize) |
|
{ |
|
u32 sector_bytes_left; |
|
u32 orig_out; |
|
struct page *cur_page; |
|
char *kaddr; |
|
|
|
if ((*cur_out / PAGE_SIZE) >= max_nr_page) |
|
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_page = out_pages[*cur_out / PAGE_SIZE]; |
|
/* Allocate a new page */ |
|
if (!cur_page) { |
|
cur_page = alloc_page(GFP_NOFS); |
|
if (!cur_page) |
|
return -ENOMEM; |
|
out_pages[*cur_out / PAGE_SIZE] = cur_page; |
|
} |
|
|
|
kaddr = kmap(cur_page); |
|
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(cur_page); |
|
|
|
if ((*cur_out / PAGE_SIZE) >= max_nr_page) |
|
return -E2BIG; |
|
|
|
cur_page = out_pages[*cur_out / PAGE_SIZE]; |
|
/* Allocate a new page */ |
|
if (!cur_page) { |
|
cur_page = alloc_page(GFP_NOFS); |
|
if (!cur_page) |
|
return -ENOMEM; |
|
out_pages[*cur_out / PAGE_SIZE] = cur_page; |
|
} |
|
kaddr = kmap(cur_page); |
|
|
|
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(cur_page); |
|
return 0; |
|
} |
|
|
|
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); |
|
const u32 sectorsize = btrfs_sb(mapping->host->i_sb)->sectorsize; |
|
struct page *page_in = NULL; |
|
char *sizes_ptr; |
|
const unsigned long max_nr_page = *out_pages; |
|
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_page > 0); |
|
*out_pages = 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 (!page_in) { |
|
page_in = find_get_page(mapping, cur_in >> PAGE_SHIFT); |
|
ASSERT(page_in); |
|
} |
|
|
|
/* 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(page_in); |
|
ret = lzo1x_1_compress(data_in + |
|
offset_in_page(cur_in), in_len, |
|
workspace->cbuf, &out_len, |
|
workspace->mem); |
|
kunmap(page_in); |
|
if (ret < 0) { |
|
pr_debug("BTRFS: lzo in loop returned %d\n", ret); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
ret = copy_compressed_data_to_page(workspace->cbuf, out_len, |
|
pages, max_nr_page, |
|
&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 (IS_ALIGNED(cur_in, PAGE_SIZE)) { |
|
put_page(page_in); |
|
page_in = NULL; |
|
} |
|
} |
|
|
|
/* Store the size of all chunks of compressed data */ |
|
sizes_ptr = kmap_local_page(pages[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 (page_in) |
|
put_page(page_in); |
|
*out_pages = 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) { |
|
char *kaddr; |
|
struct page *cur_page; |
|
u32 copy_len = min_t(u32, PAGE_SIZE - offset_in_page(*cur_in), |
|
orig_in + len - *cur_in); |
|
|
|
ASSERT(copy_len); |
|
cur_page = cb->compressed_pages[*cur_in / PAGE_SIZE]; |
|
|
|
kaddr = kmap(cur_page); |
|
memcpy(dest + *cur_in - orig_in, |
|
kaddr + offset_in_page(*cur_in), |
|
copy_len); |
|
kunmap(cur_page); |
|
|
|
*cur_in += copy_len; |
|
} |
|
} |
|
|
|
int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) |
|
{ |
|
struct workspace *workspace = list_entry(ws, struct workspace, list); |
|
const struct btrfs_fs_info *fs_info = btrfs_sb(cb->inode->i_sb); |
|
const u32 sectorsize = fs_info->sectorsize; |
|
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(cb->compressed_pages[0]); |
|
len_in = read_compress_length(kaddr); |
|
kunmap(cb->compressed_pages[0]); |
|
cur_in += LZO_LEN; |
|
|
|
/* |
|
* LZO header length check |
|
* |
|
* The total length should not exceed the maximum extent length, |
|
* and all sectors should be used. |
|
* If this happens, it means the compressed extent is corrupted. |
|
*/ |
|
if (len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) || |
|
round_up(len_in, sectorsize) < cb->compressed_len) { |
|
btrfs_err(fs_info, |
|
"invalid lzo header, lzo len %u compressed len %u", |
|
len_in, cb->compressed_len); |
|
return -EUCLEAN; |
|
} |
|
|
|
/* Go through each lzo segment */ |
|
while (cur_in < len_in) { |
|
struct page *cur_page; |
|
/* Length of the compressed segment */ |
|
u32 seg_len; |
|
u32 sector_bytes_left; |
|
size_t out_len = lzo1x_worst_compress(sectorsize); |
|
|
|
/* |
|
* We should always have enough space for one segment header |
|
* inside current sector. |
|
*/ |
|
ASSERT(cur_in / sectorsize == |
|
(cur_in + LZO_LEN - 1) / sectorsize); |
|
cur_page = cb->compressed_pages[cur_in / PAGE_SIZE]; |
|
ASSERT(cur_page); |
|
kaddr = kmap(cur_page); |
|
seg_len = read_compress_length(kaddr + offset_in_page(cur_in)); |
|
kunmap(cur_page); |
|
cur_in += LZO_LEN; |
|
|
|
if (seg_len > lzo1x_worst_compress(PAGE_SIZE)) { |
|
/* |
|
* seg_len shouldn't be larger than we have allocated |
|
* for workspace->cbuf |
|
*/ |
|
btrfs_err(fs_info, "unexpectedly large lzo segment len %u", |
|
seg_len); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
/* Copy the compressed segment payload into workspace */ |
|
copy_compressed_segment(cb, workspace->cbuf, seg_len, &cur_in); |
|
|
|
/* Decompress the data */ |
|
ret = lzo1x_decompress_safe(workspace->cbuf, seg_len, |
|
workspace->buf, &out_len); |
|
if (ret != LZO_E_OK) { |
|
btrfs_err(fs_info, "failed to decompress"); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
/* Copy the data into inode pages */ |
|
ret = btrfs_decompress_buf2page(workspace->buf, out_len, cb, cur_out); |
|
cur_out += out_len; |
|
|
|
/* All data read, exit */ |
|
if (ret == 0) |
|
goto out; |
|
ret = 0; |
|
|
|
/* Check if the sector has enough space for a segment header */ |
|
sector_bytes_left = sectorsize - (cur_in % sectorsize); |
|
if (sector_bytes_left >= LZO_LEN) |
|
continue; |
|
|
|
/* Skip the padding zeros */ |
|
cur_in += sector_bytes_left; |
|
} |
|
out: |
|
if (!ret) |
|
zero_fill_bio(cb->orig_bio); |
|
return ret; |
|
} |
|
|
|
int lzo_decompress(struct list_head *ws, unsigned char *data_in, |
|
struct page *dest_page, unsigned long start_byte, size_t srclen, |
|
size_t destlen) |
|
{ |
|
struct workspace *workspace = list_entry(ws, struct workspace, list); |
|
size_t in_len; |
|
size_t out_len; |
|
size_t max_segment_len = lzo1x_worst_compress(PAGE_SIZE); |
|
int ret = 0; |
|
char *kaddr; |
|
unsigned long bytes; |
|
|
|
if (srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2) |
|
return -EUCLEAN; |
|
|
|
in_len = read_compress_length(data_in); |
|
if (in_len != srclen) |
|
return -EUCLEAN; |
|
data_in += LZO_LEN; |
|
|
|
in_len = read_compress_length(data_in); |
|
if (in_len != srclen - LZO_LEN * 2) { |
|
ret = -EUCLEAN; |
|
goto out; |
|
} |
|
data_in += LZO_LEN; |
|
|
|
out_len = PAGE_SIZE; |
|
ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len); |
|
if (ret != LZO_E_OK) { |
|
pr_warn("BTRFS: decompress failed!\n"); |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
if (out_len < start_byte) { |
|
ret = -EIO; |
|
goto out; |
|
} |
|
|
|
/* |
|
* the caller is already checking against PAGE_SIZE, but lets |
|
* move this check closer to the memcpy/memset |
|
*/ |
|
destlen = min_t(unsigned long, destlen, PAGE_SIZE); |
|
bytes = min_t(unsigned long, destlen, out_len - start_byte); |
|
|
|
kaddr = kmap_local_page(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_local(kaddr); |
|
out: |
|
return ret; |
|
} |
|
|
|
const struct btrfs_compress_op btrfs_lzo_compress = { |
|
.workspace_manager = &wsm, |
|
.max_level = 1, |
|
.default_level = 1, |
|
};
|
|
|