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erofs: support unaligned data decompression

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Previously, compressed data was assumed as block-aligned. This
should be changed due to in-block tail-packing inline data.

Link: https://lore.kernel.org/r/20211228054604.114518-4-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This commit is contained in:
Gao Xiang 2021-12-28 13:46:02 +08:00
parent 10e5f6e482
commit ab749badf9
1 changed files with 9 additions and 8 deletions
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17
fs/erofs/decompressor.c
View file

@ -121,7 +121,7 @@ static int z_erofs_lz4_prepare_dstpages(struct z_erofs_lz4_decompress_ctx *ctx,
static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx, static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
void *inpage, unsigned int *inputmargin, int *maptype, void *inpage, unsigned int *inputmargin, int *maptype,
bool support_0padding) bool may_inplace)
{ {
struct z_erofs_decompress_req *rq = ctx->rq; struct z_erofs_decompress_req *rq = ctx->rq;
unsigned int omargin, total, i, j; unsigned int omargin, total, i, j;
@ -130,7 +130,7 @@ static void *z_erofs_lz4_handle_overlap(struct z_erofs_lz4_decompress_ctx *ctx,
if (rq->inplace_io) { if (rq->inplace_io) {
omargin = PAGE_ALIGN(ctx->oend) - ctx->oend; omargin = PAGE_ALIGN(ctx->oend) - ctx->oend;
if (rq->partial_decoding || !support_0padding || if (rq->partial_decoding || !may_inplace ||
omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize)) omargin < LZ4_DECOMPRESS_INPLACE_MARGIN(rq->inputsize))
goto docopy; goto docopy;
@ -206,15 +206,13 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
u8 *out) u8 *out)
{ {
struct z_erofs_decompress_req *rq = ctx->rq; struct z_erofs_decompress_req *rq = ctx->rq;
bool support_0padding = false, may_inplace = false;
unsigned int inputmargin; unsigned int inputmargin;
u8 *headpage, *src; u8 *headpage, *src;
bool support_0padding;
int ret, maptype; int ret, maptype;
DBG_BUGON(*rq->in == NULL); DBG_BUGON(*rq->in == NULL);
headpage = kmap_atomic(*rq->in); headpage = kmap_atomic(*rq->in);
inputmargin = 0;
support_0padding = false;
/* LZ4 decompression inplace is only safe if 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))) { if (erofs_sb_has_zero_padding(EROFS_SB(rq->sb))) {
@ -226,11 +224,13 @@ static int z_erofs_lz4_decompress_mem(struct z_erofs_lz4_decompress_ctx *ctx,
kunmap_atomic(headpage); kunmap_atomic(headpage);
return ret; return ret;
} }
may_inplace = !((rq->pageofs_in + rq->inputsize) &
(EROFS_BLKSIZ - 1));
} }
inputmargin = rq->pageofs_in; inputmargin = rq->pageofs_in;
src = z_erofs_lz4_handle_overlap(ctx, headpage, &inputmargin, src = z_erofs_lz4_handle_overlap(ctx, headpage, &inputmargin,
&maptype, support_0padding); &maptype, may_inplace);
if (IS_ERR(src)) if (IS_ERR(src))
return PTR_ERR(src); return PTR_ERR(src);
@ -320,7 +320,8 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
{ {
const unsigned int nrpages_out = const unsigned int nrpages_out =
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT; PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int righthalf = PAGE_SIZE - rq->pageofs_out; const unsigned int righthalf = min_t(unsigned int, rq->outputsize,
PAGE_SIZE - rq->pageofs_out);
unsigned char *src, *dst; unsigned char *src, *dst;
if (nrpages_out > 2) { if (nrpages_out > 2) {
@ -333,7 +334,7 @@ static int z_erofs_shifted_transform(struct z_erofs_decompress_req *rq,
return 0; return 0;
} }
src = kmap_atomic(*rq->in); src = kmap_atomic(*rq->in) + rq->pageofs_in;
if (rq->out[0]) { if (rq->out[0]) {
dst = kmap_atomic(rq->out[0]); dst = kmap_atomic(rq->out[0]);
memcpy(dst + rq->pageofs_out, src, righthalf); memcpy(dst + rq->pageofs_out, src, righthalf);