[PATCH 1/2] migration/compress: compress QEMUFile is not writable

[Wei Yang <richardw.yang@linux.intel.com>]

We open a file with empty_ops for compress QEMUFile, which means this is
not writable.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
 migration/qemu-file.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 26fb25ddc1..f3d99a96ec 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -744,11 +744,8 @@ static int qemu_compress_data(z_stream *stream, uint8_t *dest, size_t dest_len,
 /* Compress size bytes of data start at p and store the compressed
  * data to the buffer of f.
  *
- * When f is not writable, return -1 if f has no space to save the
- * compressed data.
- * When f is wirtable and it has no space to save the compressed data,
- * do fflush first, if f still has no space to save the compressed
- * data, return -1.
+ * Since the file is dummy file with empty_ops, return -1 if f has no space to
+ * save the compressed data.
  */
 ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
                                   const uint8_t *p, size_t size)
@@ -756,14 +753,7 @@ ssize_t qemu_put_compression_data(QEMUFile *f, z_stream *stream,
     ssize_t blen = IO_BUF_SIZE - f->buf_index - sizeof(int32_t);
 
     if (blen < compressBound(size)) {
-        if (!qemu_file_is_writable(f)) {
-            return -1;
-        }
-        qemu_fflush(f);
-        blen = IO_BUF_SIZE - sizeof(int32_t);
-        if (blen < compressBound(size)) {
-            return -1;
-        }
+        return -1;
     }
 
     blen = qemu_compress_data(stream, f->buf + f->buf_index + sizeof(int32_t),
-- 
2.17.1