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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2008 Oracle. All rights reserved.
*
* Based on jffs2 zlib code:
* Copyright © 2001-2007 Red Hat, Inc.
* Created by David Woodhouse <dwmw2@infradead.org>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/zlib.h>
#include <linux/zutil.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/refcount.h>
#include "compression.h"
/* workspace buffer size for s390 zlib hardware support */
#define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE)
struct workspace {
z_stream strm;
char *buf;
unsigned int buf_size;
struct list_head list;
int level;
};
static struct workspace_manager wsm;
struct list_head *zlib_get_workspace(unsigned int level)
{
struct list_head *ws = btrfs_get_workspace(BTRFS_COMPRESS_ZLIB, level);
struct workspace *workspace = list_entry(ws, struct workspace, list);
workspace->level = level;
return ws;
}
void zlib_free_workspace(struct list_head *ws)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
kvfree(workspace->strm.workspace);
kfree(workspace->buf);
kfree(workspace);
}
struct list_head *zlib_alloc_workspace(unsigned int level)
{
struct workspace *workspace;
int workspacesize;
workspace = kzalloc(sizeof(*workspace), GFP_KERNEL);
if (!workspace)
return ERR_PTR(-ENOMEM);
workspacesize = max(zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL),
zlib_inflate_workspacesize());
workspace->strm.workspace = kvzalloc(workspacesize, GFP_KERNEL | __GFP_NOWARN);
workspace->level = level;
workspace->buf = NULL;
/*
* In case of s390 zlib hardware support, allocate lager workspace
* buffer. If allocator fails, fall back to a single page buffer.
*/
if (zlib_deflate_dfltcc_enabled()) {
workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE,
__GFP_NOMEMALLOC | __GFP_NORETRY |
__GFP_NOWARN | GFP_NOIO);
workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE;
}
if (!workspace->buf) {
workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
workspace->buf_size = PAGE_SIZE;
}
if (!workspace->strm.workspace || !workspace->buf)
goto fail;
INIT_LIST_HEAD(&workspace->list);
return &workspace->list;
fail:
zlib_free_workspace(&workspace->list);
return ERR_PTR(-ENOMEM);
}
int zlib_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);
int ret;
char *data_in = NULL;
char *cfolio_out;
int nr_folios = 0;
struct folio *in_folio = NULL;
struct folio *out_folio = NULL;
unsigned long bytes_left;
unsigned int in_buf_folios;
unsigned long len = *total_out;
unsigned long nr_dest_folios = *out_folios;
const unsigned long max_out = nr_dest_folios * PAGE_SIZE;
*out_folios = 0;
*total_out = 0;
*total_in = 0;
if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
pr_warn("BTRFS: deflateInit failed\n");
ret = -EIO;
goto out;
}
workspace->strm.total_in = 0;
workspace->strm.total_out = 0;
out_folio = btrfs_alloc_compr_folio();
if (out_folio == NULL) {
ret = -ENOMEM;
goto out;
}
cfolio_out = folio_address(out_folio);
folios[0] = out_folio;
nr_folios = 1;
workspace->strm.next_in = workspace->buf;
workspace->strm.avail_in = 0;
workspace->strm.next_out = cfolio_out;
workspace->strm.avail_out = PAGE_SIZE;
while (workspace->strm.total_in < len) {
/*
* Get next input pages and copy the contents to
* the workspace buffer if required.
*/
if (workspace->strm.avail_in == 0) {
bytes_left = len - workspace->strm.total_in;
in_buf_folios = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE),
workspace->buf_size / PAGE_SIZE);
if (in_buf_folios > 1) {
int i;
for (i = 0; i < in_buf_folios; i++) {
if (data_in) {
kunmap_local(data_in);
folio_put(in_folio);
data_in = NULL;
}
ret = btrfs_compress_filemap_get_folio(mapping,
start, &in_folio);
if (ret < 0)
goto out;
data_in = kmap_local_folio(in_folio, 0);
copy_page(workspace->buf + i * PAGE_SIZE,
data_in);
start += PAGE_SIZE;
}
workspace->strm.next_in = workspace->buf;
} else {
if (data_in) {
kunmap_local(data_in);
folio_put(in_folio);
data_in = NULL;
}
ret = btrfs_compress_filemap_get_folio(mapping,
start, &in_folio);
if (ret < 0)
goto out;
data_in = kmap_local_folio(in_folio, 0);
start += PAGE_SIZE;
workspace->strm.next_in = data_in;
}
workspace->strm.avail_in = min(bytes_left,
(unsigned long) workspace->buf_size);
}
ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
if (ret != Z_OK) {
pr_debug("BTRFS: deflate in loop returned %d\n",
ret);
zlib_deflateEnd(&workspace->strm);
ret = -EIO;
goto out;
}
/* we're making it bigger, give up */
if (workspace->strm.total_in > 8192 &&
workspace->strm.total_in <
workspace->strm.total_out) {
ret = -E2BIG;
goto out;
}
/* we need another page for writing out. Test this
* before the total_in so we will pull in a new page for
* the stream end if required
*/
if (workspace->strm.avail_out == 0) {
if (nr_folios == nr_dest_folios) {
ret = -E2BIG;
goto out;
}
out_folio = btrfs_alloc_compr_folio();
if (out_folio == NULL) {
ret = -ENOMEM;
goto out;
}
cfolio_out = folio_address(out_folio);
folios[nr_folios] = out_folio;
nr_folios++;
workspace->strm.avail_out = PAGE_SIZE;
workspace->strm.next_out = cfolio_out;
}
/* we're all done */
if (workspace->strm.total_in >= len)
break;
if (workspace->strm.total_out > max_out)
break;
}
workspace->strm.avail_in = 0;
/*
* Call deflate with Z_FINISH flush parameter providing more output
* space but no more input data, until it returns with Z_STREAM_END.
*/
while (ret != Z_STREAM_END) {
ret = zlib_deflate(&workspace->strm, Z_FINISH);
if (ret == Z_STREAM_END)
break;
if (ret != Z_OK && ret != Z_BUF_ERROR) {
zlib_deflateEnd(&workspace->strm);
ret = -EIO;
goto out;
} else if (workspace->strm.avail_out == 0) {
/* Get another folio for the stream end. */
if (nr_folios == nr_dest_folios) {
ret = -E2BIG;
goto out;
}
out_folio = btrfs_alloc_compr_folio();
if (out_folio == NULL) {
ret = -ENOMEM;
goto out;
}
cfolio_out = folio_address(out_folio);
folios[nr_folios] = out_folio;
nr_folios++;
workspace->strm.avail_out = PAGE_SIZE;
workspace->strm.next_out = cfolio_out;
}
}
zlib_deflateEnd(&workspace->strm);
if (workspace->strm.total_out >= workspace->strm.total_in) {
ret = -E2BIG;
goto out;
}
ret = 0;
*total_out = workspace->strm.total_out;
*total_in = workspace->strm.total_in;
out:
*out_folios = nr_folios;
if (data_in) {
kunmap_local(data_in);
folio_put(in_folio);
}
return ret;
}
int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0, ret2;
int wbits = MAX_WBITS;
char *data_in;
size_t total_out = 0;
unsigned long folio_in_index = 0;
size_t srclen = cb->compressed_len;
unsigned long total_folios_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
unsigned long buf_start;
struct folio **folios_in = cb->compressed_folios;
data_in = kmap_local_folio(folios_in[folio_in_index], 0);
workspace->strm.next_in = data_in;
workspace->strm.avail_in = min_t(size_t, srclen, PAGE_SIZE);
workspace->strm.total_in = 0;
workspace->strm.total_out = 0;
workspace->strm.next_out = workspace->buf;
workspace->strm.avail_out = workspace->buf_size;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
wbits = -((data_in[0] >> 4) + 8);
workspace->strm.next_in += 2;
workspace->strm.avail_in -= 2;
}
if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
pr_warn("BTRFS: inflateInit failed\n");
kunmap_local(data_in);
return -EIO;
}
while (workspace->strm.total_in < srclen) {
ret = zlib_inflate(&workspace->strm, Z_NO_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END)
break;
buf_start = total_out;
total_out = workspace->strm.total_out;
/* we didn't make progress in this inflate call, we're done */
if (buf_start == total_out)
break;
ret2 = btrfs_decompress_buf2page(workspace->buf,
total_out - buf_start, cb, buf_start);
if (ret2 == 0) {
ret = 0;
goto done;
}
workspace->strm.next_out = workspace->buf;
workspace->strm.avail_out = workspace->buf_size;
if (workspace->strm.avail_in == 0) {
unsigned long tmp;
kunmap_local(data_in);
folio_in_index++;
if (folio_in_index >= total_folios_in) {
data_in = NULL;
break;
}
data_in = kmap_local_folio(folios_in[folio_in_index], 0);
workspace->strm.next_in = data_in;
tmp = srclen - workspace->strm.total_in;
workspace->strm.avail_in = min(tmp, PAGE_SIZE);
}
}
if (ret != Z_STREAM_END)
ret = -EIO;
else
ret = 0;
done:
zlib_inflateEnd(&workspace->strm);
if (data_in)
kunmap_local(data_in);
return ret;
}
int zlib_decompress(struct list_head *ws, const u8 *data_in,
struct page *dest_page, unsigned long dest_pgoff, size_t srclen,
size_t destlen)
{
struct workspace *workspace = list_entry(ws, struct workspace, list);
int ret = 0;
int wbits = MAX_WBITS;
unsigned long to_copy;
workspace->strm.next_in = data_in;
workspace->strm.avail_in = srclen;
workspace->strm.total_in = 0;
workspace->strm.next_out = workspace->buf;
workspace->strm.avail_out = workspace->buf_size;
workspace->strm.total_out = 0;
/* If it's deflate, and it's got no preset dictionary, then
we can tell zlib to skip the adler32 check. */
if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
((data_in[0] & 0x0f) == Z_DEFLATED) &&
!(((data_in[0]<<8) + data_in[1]) % 31)) {
wbits = -((data_in[0] >> 4) + 8);
workspace->strm.next_in += 2;
workspace->strm.avail_in -= 2;
}
if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
pr_warn("BTRFS: inflateInit failed\n");
return -EIO;
}
/*
* Everything (in/out buf) should be at most one sector, there should
* be no need to switch any input/output buffer.
*/
ret = zlib_inflate(&workspace->strm, Z_FINISH);
to_copy = min(workspace->strm.total_out, destlen);
if (ret != Z_STREAM_END)
goto out;
memcpy_to_page(dest_page, dest_pgoff, workspace->buf, to_copy);
out:
if (unlikely(to_copy != destlen)) {
pr_warn_ratelimited("BTRFS: inflate failed, decompressed=%lu expected=%zu\n",
to_copy, destlen);
ret = -EIO;
} else {
ret = 0;
}
zlib_inflateEnd(&workspace->strm);
if (unlikely(to_copy < destlen))
memzero_page(dest_page, dest_pgoff + to_copy, destlen - to_copy);
return ret;
}
const struct btrfs_compress_op btrfs_zlib_compress = {
.workspace_manager = &wsm,
.max_level = 9,
.default_level = BTRFS_ZLIB_DEFAULT_LEVEL,
};