Just like what was done for other algorithms, let's propagate detailed
error reasons for LZ4 instead of just -EFSCORRUPTED to users:
"corrupted compressed data":
the compressed data is malformed or
destination buffer is not large enough
"unexpected end of stream":
the compressed stream ends normally, but without producing enough
decompressed data.
"compressed data start not found":
can be returned by z_erofs_fixup_insize().
Signed-off-by: Gao Xiang <[email protected]>
---
fs/erofs/decompressor.c | 42 ++++++++++++++++++++---------------------
1 file changed, 20 insertions(+), 22 deletions(-)
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index d5d090276391..fcbb2502dbf0 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -195,26 +195,25 @@ const char *z_erofs_fixup_insize(struct
z_erofs_decompress_req *rq,
return NULL;
}
-static int z_erofs_lz4_decompress_mem(struct z_erofs_decompress_req *rq, u8
*dst)
+static const char *__z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
+ u8 *dst)
{
- bool support_0padding = false, may_inplace = false;
+ bool zeropadded = erofs_sb_has_zero_padding(EROFS_SB(rq->sb));
+ bool may_inplace = false;
unsigned int inputmargin;
u8 *out, *headpage, *src;
const char *reason;
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;
+ if (zeropadded) {
reason = z_erofs_fixup_insize(rq, headpage + rq->pageofs_in,
min_t(unsigned int, rq->inputsize,
rq->sb->s_blocksize - rq->pageofs_in));
if (reason) {
kunmap_local(headpage);
- return IS_ERR(reason) ? PTR_ERR(reason) : -EFSCORRUPTED;
+ return reason;
}
may_inplace = !((rq->pageofs_in + rq->inputsize) &
(rq->sb->s_blocksize - 1));
@@ -224,26 +223,24 @@ static int z_erofs_lz4_decompress_mem(struct
z_erofs_decompress_req *rq, u8 *dst
src = z_erofs_lz4_handle_overlap(rq, headpage, dst, &inputmargin,
&maptype, may_inplace);
if (IS_ERR(src))
- return PTR_ERR(src);
+ return ERR_CAST(src);
out = dst + rq->pageofs_out;
/* legacy format could compress extra data in a pcluster. */
- if (rq->partial_decoding || !support_0padding)
+ if (rq->partial_decoding || !zeropadded)
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)
+ reason = NULL;
+ else if (ret < 0)
+ reason = "corrupted compressed data";
+ else
+ reason = "unexpected end of stream";
- if (ret != rq->outputsize) {
- if (ret >= 0)
- memset(out + ret, 0, rq->outputsize - ret);
- ret = -EFSCORRUPTED;
- } else {
- ret = 0;
- }
-
- if (maptype == 0) {
+ if (!maptype) {
kunmap_local(headpage);
} else if (maptype == 1) {
vm_unmap_ram(src, rq->inpages);
@@ -251,15 +248,16 @@ static int z_erofs_lz4_decompress_mem(struct
z_erofs_decompress_req *rq, u8 *dst
z_erofs_put_gbuf(src);
} else if (maptype != 3) {
DBG_BUGON(1);
- return -EFAULT;
+ return ERR_PTR(-EFAULT);
}
- return ret;
+ return reason;
}
static const char *z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq,
struct page **pagepool)
{
unsigned int dst_maptype;
+ const char *reason;
void *dst;
int ret;
@@ -283,12 +281,12 @@ static const char *z_erofs_lz4_decompress(struct
z_erofs_decompress_req *rq,
dst_maptype = 2;
}
}
- ret = z_erofs_lz4_decompress_mem(rq, dst);
+ reason = __z_erofs_lz4_decompress(rq, dst);
if (!dst_maptype)
kunmap_local(dst);
else if (dst_maptype == 2)
vm_unmap_ram(dst, rq->outpages);
- return ERR_PTR(ret);
+ return reason;
}
static const char *z_erofs_transform_plain(struct z_erofs_decompress_req *rq,
--
2.43.5
