linux/fs/erofs/decompressor.c
Jingbo Xu 3acea5fc33 erofs: avoid hardcoded blocksize for subpage block support
As the first step of converting hardcoded blocksize to that specified in
on-disk superblock, convert all call sites of hardcoded blocksize to
sb->s_blocksize except for:

1) use sbi->blkszbits instead of sb->s_blocksize in
erofs_superblock_csum_verify() since sb->s_blocksize has not been
updated with the on-disk blocksize yet when the function is called.

2) use inode->i_blkbits instead of sb->s_blocksize in erofs_bread(),
since the inode operated on may be an anonymous inode in fscache mode.
Currently the anonymous inode is allocated from an anonymous mount
maintained in erofs, while in the near future we may allocate anonymous
inodes from a generic API directly and thus have no access to the
anonymous inode's i_sb.  Thus we keep the block size in i_blkbits for
anonymous inodes in fscache mode.

Be noted that this patch only gets rid of the hardcoded blocksize, in
preparation for actually setting the on-disk block size in the following
patch.  The hard limit of constraining the block size to PAGE_SIZE still
exists until the next patch.

Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230313135309.75269-2-jefflexu@linux.alibaba.com
[ Gao Xiang: fold a patch to fix incorrect truncated offsets. ]
Link: https://lore.kernel.org/r/20230413035734.15457-1-zhujia.zj@bytedance.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2023-04-17 01:15:44 +08:00

392 lines
10 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 HUAWEI, Inc.
* https://www.huawei.com/
*/
#include "compress.h"
#include <linux/module.h>
#include <linux/lz4.h>
#ifndef LZ4_DISTANCE_MAX /* history window size */
#define LZ4_DISTANCE_MAX 65535 /* set to maximum value by default */
#endif
#define LZ4_MAX_DISTANCE_PAGES (DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
#ifndef LZ4_DECOMPRESS_INPLACE_MARGIN
#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize) (((srcsize) >> 8) + 32)
#endif
struct z_erofs_lz4_decompress_ctx {
struct z_erofs_decompress_req *rq;
/* # of encoded, decoded pages */
unsigned int inpages, outpages;
/* decoded block total length (used for in-place decompression) */
unsigned int oend;
};
int z_erofs_load_lz4_config(struct super_block *sb,
struct erofs_super_block *dsb,
struct z_erofs_lz4_cfgs *lz4, int size)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
u16 distance;
if (lz4) {
if (size < sizeof(struct z_erofs_lz4_cfgs)) {
erofs_err(sb, "invalid lz4 cfgs, size=%u", size);
return -EINVAL;
}
distance = le16_to_cpu(lz4->max_distance);
sbi->lz4.max_pclusterblks = le16_to_cpu(lz4->max_pclusterblks);
if (!sbi->lz4.max_pclusterblks) {
sbi->lz4.max_pclusterblks = 1; /* reserved case */
} else if (sbi->lz4.max_pclusterblks >
erofs_blknr(sb, Z_EROFS_PCLUSTER_MAX_SIZE)) {
erofs_err(sb, "too large lz4 pclusterblks %u",
sbi->lz4.max_pclusterblks);
return -EINVAL;
}
} else {
distance = le16_to_cpu(dsb->u1.lz4_max_distance);
sbi->lz4.max_pclusterblks = 1;
}
sbi->lz4.max_distance_pages = distance ?
DIV_ROUND_UP(distance, PAGE_SIZE) + 1 :
LZ4_MAX_DISTANCE_PAGES;
return erofs_pcpubuf_growsize(sbi->lz4.max_pclusterblks);
}
/*
* Fill all gaps with bounce pages if it's a sparse page list. Also check if
* all physical pages are consecutive, which can be seen for moderate CR.
*/
static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
struct page **pagepool)
{
struct z_erofs_decompress_req *rq = ctx->rq;
struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
BITS_PER_LONG)] = { 0 };
unsigned int lz4_max_distance_pages =
EROFS_SB(rq->sb)->lz4.max_distance_pages;
void *kaddr = NULL;
unsigned int i, j, top;
top = 0;
for (i = j = 0; i < ctx->outpages; ++i, ++j) {
struct page *const page = rq->out[i];
struct page *victim;
if (j >= lz4_max_distance_pages)
j = 0;
/* 'valid' bounced can only be tested after a complete round */
if (!rq->fillgaps && test_bit(j, bounced)) {
DBG_BUGON(i < lz4_max_distance_pages);
DBG_BUGON(top >= lz4_max_distance_pages);
availables[top++] = rq->out[i - lz4_max_distance_pages];
}
if (page) {
__clear_bit(j, bounced);
if (!PageHighMem(page)) {
if (!i) {
kaddr = page_address(page);
continue;
}
if (kaddr &&
kaddr + PAGE_SIZE == page_address(page)) {
kaddr += PAGE_SIZE;
continue;
}
}
kaddr = NULL;
continue;
}
kaddr = NULL;
__set_bit(j, bounced);
if (top) {
victim = availables[--top];
get_page(victim);
} else {
victim = erofs_allocpage(pagepool,
GFP_KERNEL | __GFP_NOFAIL);
set_page_private(victim, Z_EROFS_SHORTLIVED_PAGE);
}
rq->out[i] = victim;
}
return kaddr ? 1 : 0;
}
static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
void *inpage, unsigned int *inputmargin, int *maptype,
bool may_inplace)
{
struct z_erofs_decompress_req *rq = ctx->rq;
unsigned int omargin, total, i, j;
struct page **in;
void *src, *tmp;
if (rq->inplace_io) {
omargin = PAGE_ALIGN(ctx->oend) - ctx->oend;
if (rq->partial_decoding || !may_inplace ||
omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize))
goto docopy;
for (i = 0; i < ctx->inpages; ++i) {
DBG_BUGON(rq->in[i] == NULL);
for (j = 0; j < ctx->outpages - ctx->inpages + i; ++j)
if (rq->out[j] == rq->in[i])
goto docopy;
}
}
if (ctx->inpages <= 1) {
*maptype = 0;
return inpage;
}
kunmap_atomic(inpage);
might_sleep();
src = erofs_vm_map_ram(rq->in, ctx->inpages);
if (!src)
return ERR_PTR(-ENOMEM);
*maptype = 1;
return src;
docopy:
/* Or copy compressed data which can be overlapped to per-CPU buffer */
in = rq->in;
src = erofs_get_pcpubuf(ctx->inpages);
if (!src) {
DBG_BUGON(1);
kunmap_atomic(inpage);
return ERR_PTR(-EFAULT);
}
tmp = src;
total = rq->inputsize;
while (total) {
unsigned int page_copycnt =
min_t(unsigned int, total, PAGE_SIZE - *inputmargin);
if (!inpage)
inpage = kmap_atomic(*in);
memcpy(tmp, inpage + *inputmargin, page_copycnt);
kunmap_atomic(inpage);
inpage = NULL;
tmp += page_copycnt;
total -= page_copycnt;
++in;
*inputmargin = 0;
}
*maptype = 2;
return src;
}
/*
* Get the exact inputsize with zero_padding feature.
* - For LZ4, it should work if zero_padding feature is on (5.3+);
* - For MicroLZMA, it'd be enabled all the time.
*/
int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,
unsigned int padbufsize)
{
const char *padend;
padend = memchr_inv(padbuf, 0, padbufsize);
if (!padend)
return -EFSCORRUPTED;
rq->inputsize -= padend - padbuf;
rq->pageofs_in += padend - padbuf;
return 0;
}
static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
u8 *out)
{
struct z_erofs_decompress_req *rq = ctx->rq;
bool support_0padding = false, may_inplace = false;
unsigned int inputmargin;
u8 *headpage, *src;
int ret, maptype;
DBG_BUGON(*rq->in == NULL);
headpage = kmap_atomic(*rq->in);
/* LZ4 decompression inplace is only safe if zero_padding is enabled */
if (erofs_sb_has_zero_padding(EROFS_SB(rq->sb))) {
support_0padding = true;
ret = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,
min_t(unsigned int, rq->inputsize,
rq->sb->s_blocksize - rq->pageofs_in));
if (ret) {
kunmap_atomic(headpage);
return ret;
}
may_inplace = !((rq->pageofs_in + rq->inputsize) &
(rq->sb->s_blocksize - 1));
}
inputmargin = rq->pageofs_in;
src = z_erofs_lz4_handle_overlap(ctx, headpage, &inputmargin,
&maptype, may_inplace);
if (IS_ERR(src))
return PTR_ERR(src);
/* legacy format could compress extra data in a pcluster. */
if (rq->partial_decoding || !support_0padding)
ret = LZ4_decompress_safe_partial(src + inputmargin, out,
rq->inputsize, rq->outputsize, rq->outputsize);
else
ret = LZ4_decompress_safe(src + inputmargin, out,
rq->inputsize, rq->outputsize);
if (ret != rq->outputsize) {
erofs_err(rq->sb, "failed to decompress %d in[%u, %u] out[%u]",
ret, rq->inputsize, inputmargin, rq->outputsize);
print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
16, 1, src + inputmargin, rq->inputsize, true);
print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
16, 1, out, rq->outputsize, true);
if (ret >= 0)
memset(out + ret, 0, rq->outputsize - ret);
ret = -EIO;
} else {
ret = 0;
}
if (maptype == 0) {
kunmap_atomic(headpage);
} else if (maptype == 1) {
vm_unmap_ram(src, ctx->inpages);
} else if (maptype == 2) {
erofs_put_pcpubuf(src);
} else {
DBG_BUGON(1);
return -EFAULT;
}
return ret;
}
static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
struct page **pagepool)
{
struct z_erofs_lz4_decompress_ctx ctx;
unsigned int dst_maptype;
void *dst;
int ret;
ctx.rq = rq;
ctx.oend = rq->pageofs_out + rq->outputsize;
ctx.outpages = PAGE_ALIGN(ctx.oend) >> PAGE_SHIFT;
ctx.inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
/* one optimized fast path only for non bigpcluster cases yet */
if (ctx.inpages == 1 && ctx.outpages == 1 && !rq->inplace_io) {
DBG_BUGON(!*rq->out);
dst = kmap_atomic(*rq->out);
dst_maptype = 0;
goto dstmap_out;
}
/* general decoding path which can be used for all cases */
ret = z_erofs_lz4_prepare_dstpages(&ctx, pagepool);
if (ret < 0) {
return ret;
} else if (ret > 0) {
dst = page_address(*rq->out);
dst_maptype = 1;
} else {
dst = erofs_vm_map_ram(rq->out, ctx.outpages);
if (!dst)
return -ENOMEM;
dst_maptype = 2;
}
dstmap_out:
ret = z_erofs_lz4_decompress_mem(&ctx, dst + rq->pageofs_out);
if (!dst_maptype)
kunmap_atomic(dst);
else if (dst_maptype == 2)
vm_unmap_ram(dst, ctx.outpages);
return ret;
}
static int z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
struct page **pagepool)
{
const unsigned int inpages = PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
const unsigned int outpages =
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
PAGE_SIZE - rq->pageofs_out);
const unsigned int lefthalf = rq->outputsize - righthalf;
const unsigned int interlaced_offset =
rq->alg == Z_EROFS_COMPRESSION_SHIFTED ? 0 : rq->pageofs_out;
unsigned char *src, *dst;
if (outpages > 2 && rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
DBG_BUGON(1);
return -EFSCORRUPTED;
}
if (rq->out[0] == *rq->in) {
DBG_BUGON(rq->pageofs_out);
return 0;
}
src = kmap_local_page(rq->in[inpages - 1]) + rq->pageofs_in;
if (rq->out[0]) {
dst = kmap_local_page(rq->out[0]);
memcpy(dst + rq->pageofs_out, src + interlaced_offset,
righthalf);
kunmap_local(dst);
}
if (outpages > inpages) {
DBG_BUGON(!rq->out[outpages - 1]);
if (rq->out[outpages - 1] != rq->in[inpages - 1]) {
dst = kmap_local_page(rq->out[outpages - 1]);
memcpy(dst, interlaced_offset ? src :
(src + righthalf), lefthalf);
kunmap_local(dst);
} else if (!interlaced_offset) {
memmove(src, src + righthalf, lefthalf);
}
}
kunmap_local(src);
return 0;
}
static struct z_erofs_decompressor decompressors[] = {
[Z_EROFS_COMPRESSION_SHIFTED] = {
.decompress = z_erofs_transform_plain,
.name = "shifted"
},
[Z_EROFS_COMPRESSION_INTERLACED] = {
.decompress = z_erofs_transform_plain,
.name = "interlaced"
},
[Z_EROFS_COMPRESSION_LZ4] = {
.decompress = z_erofs_lz4_decompress,
.name = "lz4"
},
#ifdef CONFIG_EROFS_FS_ZIP_LZMA
[Z_EROFS_COMPRESSION_LZMA] = {
.decompress = z_erofs_lzma_decompress,
.name = "lzma"
},
#endif
};
int z_erofs_decompress(struct z_erofs_decompress_req *rq,
struct page **pagepool)
{
return decompressors[rq->alg].decompress(rq, pagepool);
}