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