The patch allow to process image compression type defined
in the image header and choose an appropriate method for
image clusters (de)compression.
Signed-off-by: Denis Plotnikov <dplotni...@virtuozzo.com>
---
block/qcow2.c | 93 ++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 73 insertions(+), 20 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 8fa932a349..a107f76e98 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -4005,8 +4005,11 @@ fail:
}
/*
- * qcow2_compress()
+ * qcow2_zlib_compress()
*
+ * Compress @src_size bytes of data using zlib compression method
+ *
+ * @dest_size bytes.
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
@@ -4014,8 +4017,8 @@ fail:
* -1 destination buffer is not enough to store compressed data
* -2 on any other error
*/
-static ssize_t qcow2_compress(void *dest, size_t dest_size,
- const void *src, size_t src_size)
+static ssize_t qcow2_zlib_compress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
{
ssize_t ret;
z_stream strm;
@@ -4025,7 +4028,7 @@ static ssize_t qcow2_compress(void *dest, size_t
dest_size,
ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
-12, 9, Z_DEFAULT_STRATEGY);
if (ret != Z_OK) {
- return -2;
+ return -EIO;
}
/* strm.next_in is not const in old zlib versions, such as those used on
@@ -4039,7 +4042,7 @@ static ssize_t qcow2_compress(void *dest, size_t
dest_size,
if (ret == Z_STREAM_END) {
ret = dest_size - strm.avail_out;
} else {
- ret = (ret == Z_OK ? -1 : -2);
+ ret = (ret == Z_OK ? -ENOMEM : -EIO);
}
deflateEnd(&strm);
@@ -4048,10 +4051,10 @@ static ssize_t qcow2_compress(void *dest, size_t
dest_size,
}
/*
- * qcow2_decompress()
+ * qcow2_zlib_decompress()
*
* Decompress some data (not more than @src_size bytes) to produce exactly
- * @dest_size bytes.
+ * @dest_size bytes using zlib compression method
*
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
@@ -4059,8 +4062,8 @@ static ssize_t qcow2_compress(void *dest, size_t
dest_size,
* Returns: 0 on success
* -1 on fail
*/
-static ssize_t qcow2_decompress(void *dest, size_t dest_size,
- const void *src, size_t src_size)
+static ssize_t qcow2_zlib_decompress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
{
int ret = 0;
z_stream strm;
@@ -4073,7 +4076,7 @@ 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);
@@ -4081,7 +4084,7 @@ static ssize_t qcow2_decompress(void *dest, size_t
dest_size,
/* 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 = -EIO;
}
inflateEnd(&strm);
@@ -4153,20 +4156,67 @@ qcow2_co_do_compress(BlockDriverState *bs, void *dest,
size_t dest_size,
return arg.ret;
}
+/*
+ * qcow2_co_compress()
+ *
+ * Compress @src_size bytes of data using the compression
+ * method defined by the image compression type
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * a negative error code on fail
+ */
static ssize_t coroutine_fn
qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size)
{
- return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
- qcow2_compress);
+ BDRVQcow2State *s = bs->opaque;
+ Qcow2CompressFunc fn;
+
+ switch (s->compression_type) {
+ case QCOW2_COMPRESSION_TYPE_ZLIB:
+ fn = qcow2_zlib_compress;
+ break;
+
+ default:
+ return -ENOTSUP;
+ }
+
+ return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}
+/*
+ * qcow2_co_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using the compression method defined by the image
+ * compression type
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * a negative error code on fail
+ */
static ssize_t coroutine_fn
qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
const void *src, size_t src_size)
{
- return qcow2_co_do_compress(bs, dest, dest_size, src, src_size,
- qcow2_decompress);
+ BDRVQcow2State *s = bs->opaque;
+ Qcow2CompressFunc fn;
+
+ switch (s->compression_type) {
+ case QCOW2_COMPRESSION_TYPE_ZLIB:
+ fn = qcow2_zlib_decompress;
+ break;
+
+ default:
+ return -ENOTSUP;
+ }
+
+ return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}
/* XXX: put compressed sectors first, then all the cluster aligned
@@ -4178,7 +4228,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs,
uint64_t offset,
BDRVQcow2State *s = bs->opaque;
QEMUIOVector hd_qiov;
int ret;
- size_t out_len;
+ ssize_t out_len;
uint8_t *buf, *out_buf;
uint64_t cluster_offset;
@@ -4217,16 +4267,19 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs,
uint64_t offset,
out_len = qcow2_co_compress(bs, out_buf, s->cluster_size - 1,
buf, s->cluster_size);
- if (out_len == -2) {
- ret = -EINVAL;
- goto fail;
- } else if (out_len == -1) {
+ if (out_len == -ENOMEM) {
/* could not compress: write normal cluster */
ret = qcow2_co_pwritev(bs, offset, bytes, qiov, 0);
if (ret < 0) {
goto fail;
}
goto success;
+ } else if (out_len < 0) {
+ /*
+ * encounter other compression issues propagate error to the upper
level
+ */
+ ret = out_len;
+ goto fail;
}
qemu_co_mutex_lock(&s->lock);
--
2.17.0
