Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 392 insertions, 0 deletions

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
new file mode 100644
index 000000000..0cfad7437
--- /dev/null
+++ b/fs/erofs/decompressor.c
@@ -0,0 +1,392 @@
+// 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 >
+			   Z_EROFS_PCLUSTER_MAX_SIZE / EROFS_BLKSIZ) {
+			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, 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 = erofs_get_pcpubuf(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,
+				      EROFS_BLKSIZ - rq->pageofs_in));
+		if (ret) {
+			kunmap_local(headpage);
+			return ret;
+		}
+		may_inplace = !((rq->pageofs_in + rq->inputsize) &
+				(EROFS_BLKSIZ - 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);
+
+		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_local(headpage);
+	} else if (maptype == 1) {
+		vm_unmap_ram(src, ctx->inpages);
+	} else if (maptype == 2) {
+		erofs_put_pcpubuf(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 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);
+}