[Qemu-trivial] [PATCH] block: output more error messages if failed to create temporary snapshot

[riegamaths@gmail.com]

From: Dunrong Huang <riegamaths@gmail.com>

If we failed to create temporary snapshot, the error message did not match
with the error, for example:

$ TMPDIR=/tmp/bad_path qemu-system-x86_64 -enable-kvm debian.qcow2 -snapshot
qemu-system-x86_64: -enable-kvm: could not open disk image /home/mathslinux/Images/debian.qcow2: No such file or directory

Indeed, the file which cant be created is /tmp/bad_path/vl.xxxxxx,  not
debian.qcow2. so the error message makes users feel confused.

Signed-off-by: Dunrong Huang <riegamaths@gmail.com>
---
 block.c | 2 ++
 1 个文件被修改，插入 2 行(+)

diff --git a/block.c b/block.c
index 470bdcc..c9e5140 100644
--- a/block.c
+++ b/block.c
@@ -434,6 +434,8 @@ int get_tmp_filename(char *filename, int size)
     }
     fd = mkstemp(filename);
     if (fd < 0 || close(fd)) {
+        fprintf(stderr, "Could not create temporary snapshot in %s directory: "
+                "%s\n", tmpdir, strerror(errno));
         return -errno;
     }
     return 0;
-- 
1.7.12