linux/fs/erofs/decompressor.c
Sandeep Dhavale 3fc3e45fcd erofs: fix error handling in z_erofs_init_decompressor
If we get a failure at the first decompressor init (i = 0),
the clean up while loop could enter infinite loop due to wrong while
check. Check the value of i now to see if we need any clean up at all.

Fixes: 5a7cce827e ("erofs: refine z_erofs_{init,exit}_subsystem()")
Reported-by: liujinbao1 <liujinbao1@xiaomi.com>
Signed-off-by: Sandeep Dhavale <dhavale@google.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20240905060027.2388893-1-dhavale@google.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2024-09-10 00:46:34 +08:00

559 lines
15 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2019 HUAWEI, Inc.
* https://www.huawei.com/
* Copyright (C) 2024 Alibaba Cloud
*/
#include "compress.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;
};
static int z_erofs_load_lz4_config(struct super_block *sb,
struct erofs_super_block *dsb, void *data, int size)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
struct z_erofs_lz4_cfgs *lz4 = data;
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 z_erofs_gbuf_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];
} else {
victim = __erofs_allocpage(pagepool, rq->gfp, true);
if (!victim)
return -ENOMEM;
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, void *out, unsigned int *inputmargin,
int *maptype, bool may_inplace)
{
struct z_erofs_decompress_req *rq = ctx->rq;
unsigned int omargin, total, i;
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)
if (rq->out[ctx->outpages - ctx->inpages + i] !=
rq->in[i])
goto docopy;
kunmap_local(inpage);
*maptype = 3;
return out + ((ctx->outpages - ctx->inpages) << PAGE_SHIFT);
}
if (ctx->inpages <= 1) {
*maptype = 0;
return inpage;
}
kunmap_local(inpage);
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 = z_erofs_get_gbuf(ctx->inpages);
if (!src) {
DBG_BUGON(1);
kunmap_local(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_local_page(*in);
memcpy(tmp, inpage + *inputmargin, page_copycnt);
kunmap_local(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 *dst)
{
struct z_erofs_decompress_req *rq = ctx->rq;
bool support_0padding = false, may_inplace = false;
unsigned int inputmargin;
u8 *out, *headpage, *src;
int ret, maptype;
DBG_BUGON(*rq->in == NULL);
headpage = kmap_local_page(*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_local(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, dst, &inputmargin,
&maptype, may_inplace);
if (IS_ERR(src))
return PTR_ERR(src);
out = dst + rq->pageofs_out;
/* 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);
if (ret >= 0)
memset(out + ret, 0, rq->outputsize - ret);
ret = -EFSCORRUPTED;
} else {
ret = 0;
}
if (maptype == 0) {
kunmap_local(headpage);
} else if (maptype == 1) {
vm_unmap_ram(src, ctx->inpages);
} else if (maptype == 2) {
z_erofs_put_gbuf(src);
} else if (maptype != 3) {
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_local_page(*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);
if (!dst_maptype)
kunmap_local(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 nrpages_in =
PAGE_ALIGN(rq->pageofs_in + rq->inputsize) >> PAGE_SHIFT;
const unsigned int nrpages_out =
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int bs = rq->sb->s_blocksize;
unsigned int cur = 0, ni = 0, no, pi, po, insz, cnt;
u8 *kin;
if (rq->outputsize > rq->inputsize)
return -EOPNOTSUPP;
if (rq->alg == Z_EROFS_COMPRESSION_INTERLACED) {
cur = bs - (rq->pageofs_out & (bs - 1));
pi = (rq->pageofs_in + rq->inputsize - cur) & ~PAGE_MASK;
cur = min(cur, rq->outputsize);
if (cur && rq->out[0]) {
kin = kmap_local_page(rq->in[nrpages_in - 1]);
if (rq->out[0] == rq->in[nrpages_in - 1]) {
memmove(kin + rq->pageofs_out, kin + pi, cur);
flush_dcache_page(rq->out[0]);
} else {
memcpy_to_page(rq->out[0], rq->pageofs_out,
kin + pi, cur);
}
kunmap_local(kin);
}
rq->outputsize -= cur;
}
for (; rq->outputsize; rq->pageofs_in = 0, cur += PAGE_SIZE, ni++) {
insz = min(PAGE_SIZE - rq->pageofs_in, rq->outputsize);
rq->outputsize -= insz;
if (!rq->in[ni])
continue;
kin = kmap_local_page(rq->in[ni]);
pi = 0;
do {
no = (rq->pageofs_out + cur + pi) >> PAGE_SHIFT;
po = (rq->pageofs_out + cur + pi) & ~PAGE_MASK;
DBG_BUGON(no >= nrpages_out);
cnt = min(insz - pi, PAGE_SIZE - po);
if (rq->out[no] == rq->in[ni]) {
memmove(kin + po,
kin + rq->pageofs_in + pi, cnt);
flush_dcache_page(rq->out[no]);
} else if (rq->out[no]) {
memcpy_to_page(rq->out[no], po,
kin + rq->pageofs_in + pi, cnt);
}
pi += cnt;
} while (pi < insz);
kunmap_local(kin);
}
DBG_BUGON(ni > nrpages_in);
return 0;
}
int z_erofs_stream_switch_bufs(struct z_erofs_stream_dctx *dctx, void **dst,
void **src, struct page **pgpl)
{
struct z_erofs_decompress_req *rq = dctx->rq;
struct super_block *sb = rq->sb;
struct page **pgo, *tmppage;
unsigned int j;
if (!dctx->avail_out) {
if (++dctx->no >= dctx->outpages || !rq->outputsize) {
erofs_err(sb, "insufficient space for decompressed data");
return -EFSCORRUPTED;
}
if (dctx->kout)
kunmap_local(dctx->kout);
dctx->avail_out = min(rq->outputsize, PAGE_SIZE - rq->pageofs_out);
rq->outputsize -= dctx->avail_out;
pgo = &rq->out[dctx->no];
if (!*pgo && rq->fillgaps) { /* deduped */
*pgo = erofs_allocpage(pgpl, rq->gfp);
if (!*pgo) {
dctx->kout = NULL;
return -ENOMEM;
}
set_page_private(*pgo, Z_EROFS_SHORTLIVED_PAGE);
}
if (*pgo) {
dctx->kout = kmap_local_page(*pgo);
*dst = dctx->kout + rq->pageofs_out;
} else {
*dst = dctx->kout = NULL;
}
rq->pageofs_out = 0;
}
if (dctx->inbuf_pos == dctx->inbuf_sz && rq->inputsize) {
if (++dctx->ni >= dctx->inpages) {
erofs_err(sb, "invalid compressed data");
return -EFSCORRUPTED;
}
if (dctx->kout) /* unlike kmap(), take care of the orders */
kunmap_local(dctx->kout);
kunmap_local(dctx->kin);
dctx->inbuf_sz = min_t(u32, rq->inputsize, PAGE_SIZE);
rq->inputsize -= dctx->inbuf_sz;
dctx->kin = kmap_local_page(rq->in[dctx->ni]);
*src = dctx->kin;
dctx->bounced = false;
if (dctx->kout) {
j = (u8 *)*dst - dctx->kout;
dctx->kout = kmap_local_page(rq->out[dctx->no]);
*dst = dctx->kout + j;
}
dctx->inbuf_pos = 0;
}
/*
* Handle overlapping: Use the given bounce buffer if the input data is
* under processing; Or utilize short-lived pages from the on-stack page
* pool, where pages are shared among the same request. Note that only
* a few inplace I/O pages need to be doubled.
*/
if (!dctx->bounced && rq->out[dctx->no] == rq->in[dctx->ni]) {
memcpy(dctx->bounce, *src, dctx->inbuf_sz);
*src = dctx->bounce;
dctx->bounced = true;
}
for (j = dctx->ni + 1; j < dctx->inpages; ++j) {
if (rq->out[dctx->no] != rq->in[j])
continue;
tmppage = erofs_allocpage(pgpl, rq->gfp);
if (!tmppage)
return -ENOMEM;
set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE);
copy_highpage(tmppage, rq->in[j]);
rq->in[j] = tmppage;
}
return 0;
}
const struct z_erofs_decompressor *z_erofs_decomp[] = {
[Z_EROFS_COMPRESSION_SHIFTED] = &(const struct z_erofs_decompressor) {
.decompress = z_erofs_transform_plain,
.name = "shifted"
},
[Z_EROFS_COMPRESSION_INTERLACED] = &(const struct z_erofs_decompressor) {
.decompress = z_erofs_transform_plain,
.name = "interlaced"
},
[Z_EROFS_COMPRESSION_LZ4] = &(const struct z_erofs_decompressor) {
.config = z_erofs_load_lz4_config,
.decompress = z_erofs_lz4_decompress,
.init = z_erofs_gbuf_init,
.exit = z_erofs_gbuf_exit,
.name = "lz4"
},
#ifdef CONFIG_EROFS_FS_ZIP_LZMA
[Z_EROFS_COMPRESSION_LZMA] = &z_erofs_lzma_decomp,
#endif
#ifdef CONFIG_EROFS_FS_ZIP_DEFLATE
[Z_EROFS_COMPRESSION_DEFLATE] = &z_erofs_deflate_decomp,
#endif
#ifdef CONFIG_EROFS_FS_ZIP_ZSTD
[Z_EROFS_COMPRESSION_ZSTD] = &z_erofs_zstd_decomp,
#endif
};
int z_erofs_parse_cfgs(struct super_block *sb, struct erofs_super_block *dsb)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
unsigned int algs, alg;
erofs_off_t offset;
int size, ret = 0;
if (!erofs_sb_has_compr_cfgs(sbi)) {
sbi->available_compr_algs = 1 << Z_EROFS_COMPRESSION_LZ4;
return z_erofs_load_lz4_config(sb, dsb, NULL, 0);
}
sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
erofs_err(sb, "unidentified algorithms %x, please upgrade kernel",
sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
return -EOPNOTSUPP;
}
erofs_init_metabuf(&buf, sb);
offset = EROFS_SUPER_OFFSET + sbi->sb_size;
alg = 0;
for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
const struct z_erofs_decompressor *dec = z_erofs_decomp[alg];
void *data;
if (!(algs & 1))
continue;
data = erofs_read_metadata(sb, &buf, &offset, &size);
if (IS_ERR(data)) {
ret = PTR_ERR(data);
break;
}
if (alg < Z_EROFS_COMPRESSION_MAX && dec && dec->config) {
ret = dec->config(sb, dsb, data, size);
} else {
erofs_err(sb, "algorithm %d isn't enabled on this kernel",
alg);
ret = -EOPNOTSUPP;
}
kfree(data);
if (ret)
break;
}
erofs_put_metabuf(&buf);
return ret;
}
int __init z_erofs_init_decompressor(void)
{
int i, err;
for (i = 0; i < Z_EROFS_COMPRESSION_MAX; ++i) {
err = z_erofs_decomp[i] ? z_erofs_decomp[i]->init() : 0;
if (err) {
while (i--)
if (z_erofs_decomp[i])
z_erofs_decomp[i]->exit();
return err;
}
}
return 0;
}
void z_erofs_exit_decompressor(void)
{
int i;
for (i = 0; i < Z_EROFS_COMPRESSION_MAX; ++i)
if (z_erofs_decomp[i])
z_erofs_decomp[i]->exit();
}