510 lines
12 KiB
C
510 lines
12 KiB
C
|
/*
|
||
|
* Copyright (C) 2008 Oracle. All rights reserved.
|
||
|
*
|
||
|
* This program is free software; you can redistribute it and/or
|
||
|
* modify it under the terms of the GNU General Public
|
||
|
* License v2 as published by the Free Software Foundation.
|
||
|
*
|
||
|
* This program is distributed in the hope that it will be useful,
|
||
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
* General Public License for more details.
|
||
|
*
|
||
|
* You should have received a copy of the GNU General Public
|
||
|
* License along with this program; if not, write to the
|
||
|
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
||
|
* Boston, MA 021110-1307, USA.
|
||
|
*/
|
||
|
|
||
|
#include <linux/kernel.h>
|
||
|
#include <linux/slab.h>
|
||
|
#include <linux/vmalloc.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 "compression.h"
|
||
|
|
||
|
#define LZO_LEN 4
|
||
|
|
||
|
struct workspace {
|
||
|
void *mem;
|
||
|
void *buf; /* where compressed data goes */
|
||
|
void *cbuf; /* where decompressed data goes */
|
||
|
struct list_head list;
|
||
|
};
|
||
|
|
||
|
static void lzo_free_workspace(struct list_head *ws)
|
||
|
{
|
||
|
struct workspace *workspace = list_entry(ws, struct workspace, list);
|
||
|
|
||
|
vfree(workspace->buf);
|
||
|
vfree(workspace->cbuf);
|
||
|
vfree(workspace->mem);
|
||
|
kfree(workspace);
|
||
|
}
|
||
|
|
||
|
static struct list_head *lzo_alloc_workspace(void)
|
||
|
{
|
||
|
struct workspace *workspace;
|
||
|
|
||
|
workspace = kzalloc(sizeof(*workspace), GFP_NOFS);
|
||
|
if (!workspace)
|
||
|
return ERR_PTR(-ENOMEM);
|
||
|
|
||
|
workspace->mem = vmalloc(LZO1X_MEM_COMPRESS);
|
||
|
workspace->buf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
|
||
|
workspace->cbuf = vmalloc(lzo1x_worst_compress(PAGE_CACHE_SIZE));
|
||
|
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(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, unsigned long len,
|
||
|
struct page **pages,
|
||
|
unsigned long nr_dest_pages,
|
||
|
unsigned long *out_pages,
|
||
|
unsigned long *total_in,
|
||
|
unsigned long *total_out,
|
||
|
unsigned long max_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;
|
||
|
|
||
|
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_CACHE_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_CACHE_SIZE - LZO_LEN;
|
||
|
|
||
|
/* compress at most one page of data each time */
|
||
|
in_len = min(len, PAGE_CACHE_SIZE);
|
||
|
while (tot_in < len) {
|
||
|
ret = lzo1x_1_compress(data_in, in_len, workspace->cbuf,
|
||
|
&out_len, workspace->mem);
|
||
|
if (ret != LZO_E_OK) {
|
||
|
printk(KERN_DEBUG "btrfs deflate in loop returned %d\n",
|
||
|
ret);
|
||
|
ret = -1;
|
||
|
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 = -1;
|
||
|
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_CACHE_SIZE;
|
||
|
out_offset = 0;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* we're making it bigger, give up */
|
||
|
if (tot_in > 8192 && tot_in < tot_out)
|
||
|
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);
|
||
|
page_cache_release(in_page);
|
||
|
|
||
|
start += PAGE_CACHE_SIZE;
|
||
|
in_page = find_get_page(mapping, start >> PAGE_CACHE_SHIFT);
|
||
|
data_in = kmap(in_page);
|
||
|
in_len = min(bytes_left, PAGE_CACHE_SIZE);
|
||
|
}
|
||
|
|
||
|
if (tot_out > tot_in)
|
||
|
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);
|
||
|
page_cache_release(in_page);
|
||
|
}
|
||
|
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
static int lzo_decompress_biovec(struct list_head *ws,
|
||
|
struct page **pages_in,
|
||
|
u64 disk_start,
|
||
|
struct bio_vec *bvec,
|
||
|
int vcnt,
|
||
|
size_t srclen)
|
||
|
{
|
||
|
struct workspace *workspace = list_entry(ws, struct workspace, list);
|
||
|
int ret = 0;
|
||
|
char *data_in;
|
||
|
unsigned long page_bytes_left;
|
||
|
unsigned long page_in_index = 0;
|
||
|
unsigned long page_out_index = 0;
|
||
|
struct page *page_out;
|
||
|
unsigned long total_pages_in = (srclen + PAGE_CACHE_SIZE - 1) /
|
||
|
PAGE_CACHE_SIZE;
|
||
|
unsigned long buf_start;
|
||
|
unsigned long buf_offset = 0;
|
||
|
unsigned long bytes;
|
||
|
unsigned long working_bytes;
|
||
|
unsigned long pg_offset;
|
||
|
unsigned long start_byte;
|
||
|
unsigned long current_buf_start;
|
||
|
char *kaddr;
|
||
|
|
||
|
size_t in_len;
|
||
|
size_t out_len;
|
||
|
unsigned long in_offset;
|
||
|
unsigned long in_page_bytes_left;
|
||
|
unsigned long tot_in;
|
||
|
unsigned long tot_out;
|
||
|
unsigned long tot_len;
|
||
|
char *buf;
|
||
|
|
||
|
data_in = kmap(pages_in[0]);
|
||
|
tot_len = read_compress_length(data_in);
|
||
|
|
||
|
tot_in = LZO_LEN;
|
||
|
in_offset = LZO_LEN;
|
||
|
tot_len = min_t(size_t, srclen, tot_len);
|
||
|
in_page_bytes_left = PAGE_CACHE_SIZE - LZO_LEN;
|
||
|
|
||
|
tot_out = 0;
|
||
|
page_out = bvec[0].bv_page;
|
||
|
page_bytes_left = PAGE_CACHE_SIZE;
|
||
|
pg_offset = 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;
|
||
|
|
||
|
tot_in += in_len;
|
||
|
working_bytes = in_len;
|
||
|
|
||
|
/* fast path: avoid using the working buffer */
|
||
|
if (in_page_bytes_left >= in_len) {
|
||
|
buf = data_in + in_offset;
|
||
|
bytes = in_len;
|
||
|
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;
|
||
|
|
||
|
kunmap(pages_in[page_in_index]);
|
||
|
page_in_index++;
|
||
|
if (page_in_index >= total_pages_in) {
|
||
|
ret = -1;
|
||
|
data_in = NULL;
|
||
|
goto done;
|
||
|
}
|
||
|
data_in = kmap(pages_in[page_in_index]);
|
||
|
|
||
|
in_page_bytes_left = PAGE_CACHE_SIZE;
|
||
|
in_offset = 0;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
out_len = lzo1x_worst_compress(PAGE_CACHE_SIZE);
|
||
|
ret = lzo1x_decompress_safe(buf, in_len, workspace->buf,
|
||
|
&out_len);
|
||
|
if (ret != LZO_E_OK) {
|
||
|
printk(KERN_WARNING "btrfs decompress failed\n");
|
||
|
ret = -1;
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* buf start is the byte offset we're of the start of
|
||
|
* our workspace buffer
|
||
|
*/
|
||
|
buf_start = tot_out;
|
||
|
|
||
|
/* tot_out is the last byte of the workspace buffer */
|
||
|
tot_out += out_len;
|
||
|
|
||
|
working_bytes = tot_out - buf_start;
|
||
|
|
||
|
/*
|
||
|
* start_byte is the first byte of the page we're currently
|
||
|
* copying into relative to the start of the compressed data.
|
||
|
*/
|
||
|
start_byte = page_offset(page_out) - disk_start;
|
||
|
|
||
|
if (working_bytes == 0) {
|
||
|
/* we didn't make progress in this inflate
|
||
|
* call, we're done
|
||
|
*/
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
/* we haven't yet hit data corresponding to this page */
|
||
|
if (tot_out <= start_byte)
|
||
|
continue;
|
||
|
|
||
|
/*
|
||
|
* the start of the data we care about is offset into
|
||
|
* the middle of our working buffer
|
||
|
*/
|
||
|
if (tot_out > start_byte && buf_start < start_byte) {
|
||
|
buf_offset = start_byte - buf_start;
|
||
|
working_bytes -= buf_offset;
|
||
|
} else {
|
||
|
buf_offset = 0;
|
||
|
}
|
||
|
current_buf_start = buf_start;
|
||
|
|
||
|
/* copy bytes from the working buffer into the pages */
|
||
|
while (working_bytes > 0) {
|
||
|
bytes = min(PAGE_CACHE_SIZE - pg_offset,
|
||
|
PAGE_CACHE_SIZE - buf_offset);
|
||
|
bytes = min(bytes, working_bytes);
|
||
|
kaddr = kmap_atomic(page_out, KM_USER0);
|
||
|
memcpy(kaddr + pg_offset, workspace->buf + buf_offset,
|
||
|
bytes);
|
||
|
kunmap_atomic(kaddr, KM_USER0);
|
||
|
flush_dcache_page(page_out);
|
||
|
|
||
|
pg_offset += bytes;
|
||
|
page_bytes_left -= bytes;
|
||
|
buf_offset += bytes;
|
||
|
working_bytes -= bytes;
|
||
|
current_buf_start += bytes;
|
||
|
|
||
|
/* check if we need to pick another page */
|
||
|
if (page_bytes_left == 0) {
|
||
|
page_out_index++;
|
||
|
if (page_out_index >= vcnt) {
|
||
|
ret = 0;
|
||
|
goto done;
|
||
|
}
|
||
|
|
||
|
page_out = bvec[page_out_index].bv_page;
|
||
|
pg_offset = 0;
|
||
|
page_bytes_left = PAGE_CACHE_SIZE;
|
||
|
start_byte = page_offset(page_out) - disk_start;
|
||
|
|
||
|
/*
|
||
|
* make sure our new page is covered by this
|
||
|
* working buffer
|
||
|
*/
|
||
|
if (tot_out <= start_byte)
|
||
|
break;
|
||
|
|
||
|
/* the next page in the biovec might not
|
||
|
* be adjacent to the last page, but it
|
||
|
* might still be found inside this working
|
||
|
* buffer. bump our offset pointer
|
||
|
*/
|
||
|
if (tot_out > start_byte &&
|
||
|
current_buf_start < start_byte) {
|
||
|
buf_offset = start_byte - buf_start;
|
||
|
working_bytes = tot_out - start_byte;
|
||
|
current_buf_start = buf_start +
|
||
|
buf_offset;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
done:
|
||
|
if (data_in)
|
||
|
kunmap(pages_in[page_in_index]);
|
||
|
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 tot_len;
|
||
|
int ret = 0;
|
||
|
char *kaddr;
|
||
|
unsigned long bytes;
|
||
|
|
||
|
BUG_ON(srclen < LZO_LEN);
|
||
|
|
||
|
tot_len = read_compress_length(data_in);
|
||
|
data_in += LZO_LEN;
|
||
|
|
||
|
in_len = read_compress_length(data_in);
|
||
|
data_in += LZO_LEN;
|
||
|
|
||
|
out_len = PAGE_CACHE_SIZE;
|
||
|
ret = lzo1x_decompress_safe(data_in, in_len, workspace->buf, &out_len);
|
||
|
if (ret != LZO_E_OK) {
|
||
|
printk(KERN_WARNING "btrfs decompress failed!\n");
|
||
|
ret = -1;
|
||
|
goto out;
|
||
|
}
|
||
|
|
||
|
if (out_len < start_byte) {
|
||
|
ret = -1;
|
||
|
goto out;
|
||
|
}
|
||
|
|
||
|
bytes = min_t(unsigned long, destlen, out_len - start_byte);
|
||
|
|
||
|
kaddr = kmap_atomic(dest_page, KM_USER0);
|
||
|
memcpy(kaddr, workspace->buf + start_byte, bytes);
|
||
|
kunmap_atomic(kaddr, KM_USER0);
|
||
|
out:
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
struct btrfs_compress_op btrfs_lzo_compress = {
|
||
|
.alloc_workspace = lzo_alloc_workspace,
|
||
|
.free_workspace = lzo_free_workspace,
|
||
|
.compress_pages = lzo_compress_pages,
|
||
|
.decompress_biovec = lzo_decompress_biovec,
|
||
|
.decompress = lzo_decompress,
|
||
|
};
|