#define ZLIB_CONST
#include <zlib.h>
+#ifdef CONFIG_ZSTD
+#include <zstd.h>
+#include <zstd_errors.h>
+#endif
+
#include "qcow2.h"
+#include "block/block-io.h"
#include "block/thread-pool.h"
#include "crypto.h"
{
int ret;
BDRVQcow2State *s = bs->opaque;
- ThreadPool *pool = aio_get_thread_pool(bdrv_get_aio_context(bs));
qemu_co_mutex_lock(&s->lock);
while (s->nb_threads >= QCOW2_MAX_THREADS) {
s->nb_threads++;
qemu_co_mutex_unlock(&s->lock);
- ret = thread_pool_submit_co(pool, func, arg);
+ ret = thread_pool_submit_co(func, arg);
qemu_co_mutex_lock(&s->lock);
s->nb_threads--;
} Qcow2CompressData;
/*
- * qcow2_compress()
+ * qcow2_zlib_compress()
+ *
+ * Compress @src_size bytes of data using zlib compression method
*
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
* -ENOMEM destination buffer is not enough to store compressed data
* -EIO 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;
}
/*
- * 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
* Returns: 0 on success
* -EIO 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;
z_stream strm;
return ret;
}
+#ifdef CONFIG_ZSTD
+
+/*
+ * qcow2_zstd_compress()
+ *
+ * Compress @src_size bytes of data using zstd compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: compressed size on success
+ * -ENOMEM destination buffer is not enough to store compressed data
+ * -EIO on any other error
+ */
+static ssize_t qcow2_zstd_compress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
+{
+ ssize_t ret;
+ size_t zstd_ret;
+ ZSTD_outBuffer output = {
+ .dst = dest,
+ .size = dest_size,
+ .pos = 0
+ };
+ ZSTD_inBuffer input = {
+ .src = src,
+ .size = src_size,
+ .pos = 0
+ };
+ ZSTD_CCtx *cctx = ZSTD_createCCtx();
+
+ if (!cctx) {
+ return -EIO;
+ }
+ /*
+ * Use the zstd streamed interface for symmetry with decompression,
+ * where streaming is essential since we don't record the exact
+ * compressed size.
+ *
+ * ZSTD_compressStream2() tries to compress everything it could
+ * with a single call. Although, ZSTD docs says that:
+ * "You must continue calling ZSTD_compressStream2() with ZSTD_e_end
+ * until it returns 0, at which point you are free to start a new frame",
+ * in out tests we saw the only case when it returned with >0 -
+ * when the output buffer was too small. In that case,
+ * ZSTD_compressStream2() expects a bigger buffer on the next call.
+ * We can't provide a bigger buffer because we are limited with dest_size
+ * which we pass to the ZSTD_compressStream2() at once.
+ * So, we don't need any loops and just abort the compression when we
+ * don't get 0 result on the first call.
+ */
+ zstd_ret = ZSTD_compressStream2(cctx, &output, &input, ZSTD_e_end);
+
+ if (zstd_ret) {
+ if (zstd_ret > output.size - output.pos) {
+ ret = -ENOMEM;
+ } else {
+ ret = -EIO;
+ }
+ goto out;
+ }
+
+ /* make sure that zstd didn't overflow the dest buffer */
+ assert(output.pos <= dest_size);
+ ret = output.pos;
+out:
+ ZSTD_freeCCtx(cctx);
+ return ret;
+}
+
+/*
+ * qcow2_zstd_decompress()
+ *
+ * Decompress some data (not more than @src_size bytes) to produce exactly
+ * @dest_size bytes using zstd compression method
+ *
+ * @dest - destination buffer, @dest_size bytes
+ * @src - source buffer, @src_size bytes
+ *
+ * Returns: 0 on success
+ * -EIO on any error
+ */
+static ssize_t qcow2_zstd_decompress(void *dest, size_t dest_size,
+ const void *src, size_t src_size)
+{
+ size_t zstd_ret = 0;
+ ssize_t ret = 0;
+ ZSTD_outBuffer output = {
+ .dst = dest,
+ .size = dest_size,
+ .pos = 0
+ };
+ ZSTD_inBuffer input = {
+ .src = src,
+ .size = src_size,
+ .pos = 0
+ };
+ ZSTD_DCtx *dctx = ZSTD_createDCtx();
+
+ if (!dctx) {
+ return -EIO;
+ }
+
+ /*
+ * The compressed stream from the input buffer may consist of more
+ * than one zstd frame. So we iterate until we get a fully
+ * uncompressed cluster.
+ * From zstd docs related to ZSTD_decompressStream:
+ * "return : 0 when a frame is completely decoded and fully flushed"
+ * We suppose that this means: each time ZSTD_decompressStream reads
+ * only ONE full frame and returns 0 if and only if that frame
+ * is completely decoded and flushed. Only after returning 0,
+ * ZSTD_decompressStream reads another ONE full frame.
+ */
+ while (output.pos < output.size) {
+ size_t last_in_pos = input.pos;
+ size_t last_out_pos = output.pos;
+ zstd_ret = ZSTD_decompressStream(dctx, &output, &input);
+
+ if (ZSTD_isError(zstd_ret)) {
+ ret = -EIO;
+ break;
+ }
+
+ /*
+ * The ZSTD manual is vague about what to do if it reads
+ * the buffer partially, and we don't want to get stuck
+ * in an infinite loop where ZSTD_decompressStream
+ * returns > 0 waiting for another input chunk. So, we add
+ * a check which ensures that the loop makes some progress
+ * on each step.
+ */
+ if (last_in_pos >= input.pos &&
+ last_out_pos >= output.pos) {
+ ret = -EIO;
+ break;
+ }
+ }
+ /*
+ * Make sure that we have the frame fully flushed here
+ * if not, we somehow managed to get uncompressed cluster
+ * greater then the cluster size, possibly because of its
+ * damage.
+ */
+ if (zstd_ret > 0) {
+ ret = -EIO;
+ }
+
+ ZSTD_freeDCtx(dctx);
+ assert(ret == 0 || ret == -EIO);
+ return ret;
+}
+#endif
+
static int qcow2_compress_pool_func(void *opaque)
{
Qcow2CompressData *data = opaque;
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: compressed size on success
+ * a negative error code on failure
+ */
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;
+
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+ fn = qcow2_zstd_compress;
+ break;
+#endif
+ default:
+ abort();
+ }
+
+ 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 failure
+ */
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;
+
+#ifdef CONFIG_ZSTD
+ case QCOW2_COMPRESSION_TYPE_ZSTD:
+ fn = qcow2_zstd_decompress;
+ break;
+#endif
+ default:
+ abort();
+ }
+
+ return qcow2_co_do_compress(bs, dest, dest_size, src, src_size, fn);
}
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