block/qcow2-threads: fix qcow2_decompress

On success path we return what inflate() returns instead of 0. And it
most probably works for Z_STREAM_END as it is positive, but is
definitely broken for Z_BUF_ERROR.

While being here, switch to errno return code, to be closer to
qcow2_compress API (and usual expectations).

Revert condition in if to be more positive. Drop dead initialization of
ret.

Cc: qemu-stable@nongnu.org # v4.0
Fixes: 341926ab83
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20200302150930.16218-1-vsementsov@virtuozzo.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2020-03-02 18:09:30 +03:00 committed by Max Reitz
parent fc124ea1db
commit e7266570f2

View File

@ -128,12 +128,12 @@ static ssize_t qcow2_compress(void *dest, size_t dest_size,
* @src - source buffer, @src_size bytes
*
* Returns: 0 on success
* -1 on fail
* -EIO on fail
*/
static ssize_t qcow2_decompress(void *dest, size_t dest_size,
const void *src, size_t src_size)
{
int ret = 0;
int ret;
z_stream strm;
memset(&strm, 0, sizeof(strm));
@ -144,17 +144,19 @@ static ssize_t qcow2_decompress(void *dest, size_t dest_size,
ret = inflateInit2(&strm, -12);
if (ret != Z_OK) {
return -1;
return -EIO;
}
ret = inflate(&strm, Z_FINISH);
if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || strm.avail_out != 0) {
if ((ret == Z_STREAM_END || ret == Z_BUF_ERROR) && strm.avail_out == 0) {
/*
* We approve Z_BUF_ERROR because we need @dest buffer to be filled, but
* @src buffer may be processed partly (because in qcow2 we know size of
* compressed data with precision of one sector)
*/
ret = -1;
ret = 0;
} else {
ret = -EIO;
}
inflateEnd(&strm);