Commit 10e5f6e4 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: introduce z_erofs_fixup_insize 

To prepare for the upcoming ztailpacking feature, introduce
z_erofs_fixup_insize() and pageofs_in to wrap up the process
to get the exact compressed size via zero padding.

Link: https://lore.kernel.org/r/20211228054604.114518-3-hsiangkao@linux.alibaba.com


Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent d67aee76

fs/erofs/compress.h

+3 −1
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ struct z_erofs_decompress_req { 
	struct super_block *sb;

	struct page **in, **out;



	unsigned short pageofs_out;

	unsigned short pageofs_in, pageofs_out;

	unsigned int inputsize, outputsize;



	/* indicate the algorithm will be used for decompression */
@@ -87,6 +87,8 @@ static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi, 
	return page->mapping == MNGD_MAPPING(sbi);

}



int z_erofs_fixup_insize(struct z_erofs_decompress_req *rq, const char *padbuf,

			 unsigned int padbufsize);

int z_erofs_decompress(struct z_erofs_decompress_req *rq,

		       struct page **pagepool);

fs/erofs/decompressor.c

+25 −9
Original line number Diff line number Diff line
@@ -184,6 +184,24 @@ static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx, 
	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)

{
@@ -198,21 +216,19 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx, 
	inputmargin = 0;

	support_0padding = false;



	/* decompression inplace is only safe when zero_padding is enabled */

	/* LZ4 decompression inplace is only safe if zero_padding is enabled */

	if (erofs_sb_has_zero_padding(EROFS_SB(rq->sb))) {

		support_0padding = true;



		while (!headpage[inputmargin & ~PAGE_MASK])

			if (!(++inputmargin & ~PAGE_MASK))

				break;



		if (inputmargin >= rq->inputsize) {

		ret = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,

				min_t(unsigned int, rq->inputsize,

				      EROFS_BLKSIZ - rq->pageofs_in));

		if (ret) {

			kunmap_atomic(headpage);

			return -EIO;

			return ret;

		}

	}



	rq->inputsize -= inputmargin;

	inputmargin = rq->pageofs_in;

	src = z_erofs_lz4_handle_overlap(ctx, headpage, &inputmargin,

					 &maptype, support_0padding);

	if (IS_ERR(src))

fs/erofs/decompressor_lzma.c

+8 −11
Original line number Diff line number Diff line
@@ -156,7 +156,7 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, 
		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;

	const unsigned int nrpages_in =

		PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;

	unsigned int inputmargin, inlen, outlen, pageofs;

	unsigned int inlen, outlen, pageofs;

	struct z_erofs_lzma *strm;

	u8 *kin;

	bool bounced = false;
@@ -164,16 +164,13 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, 


	/* 1. get the exact LZMA compressed size */

	kin = kmap(*rq->in);

	inputmargin = 0;

	while (!kin[inputmargin & ~PAGE_MASK])

		if (!(++inputmargin & ~PAGE_MASK))

			break;



	if (inputmargin >= PAGE_SIZE) {

	err = z_erofs_fixup_insize(rq, kin + rq->pageofs_in,

				   min_t(unsigned int, rq->inputsize,

					 EROFS_BLKSIZ - rq->pageofs_in));

	if (err) {

		kunmap(*rq->in);

		return -EFSCORRUPTED;

		return err;

	}

	rq->inputsize -= inputmargin;



	/* 2. get an available lzma context */

again:
@@ -193,9 +190,9 @@ int z_erofs_lzma_decompress(struct z_erofs_decompress_req *rq, 
	xz_dec_microlzma_reset(strm->state, inlen, outlen,

			       !rq->partial_decoding);

	pageofs = rq->pageofs_out;

	strm->buf.in = kin + inputmargin;

	strm->buf.in = kin + rq->pageofs_in;

	strm->buf.in_pos = 0;

	strm->buf.in_size = min_t(u32, inlen, PAGE_SIZE - inputmargin);

	strm->buf.in_size = min_t(u32, inlen, PAGE_SIZE - rq->pageofs_in);

	inlen -= strm->buf.in_size;

	strm->buf.out = NULL;

	strm->buf.out_pos = 0;