[Qemu-devel] [PATCH v2] block: output more error messages if failed to create temporary snapshot

[riegamaths]

From: Dunrong Huang <address@hidden>

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 <address@hidden>
---
v1 -> v2:
   Output error message only if fd < 0
 block.c | 7 ++++++-
 1 个文件被修改，插入 6 行(+)，删除 1 行(-)

diff --git a/block.c b/block.c
index 470bdcc..2dd0c5b 100644
--- a/block.c
+++ b/block.c
@@ -433,7 +433,12 @@ int get_tmp_filename(char *filename, int size)
         return -EOVERFLOW;
     }
     fd = mkstemp(filename);
-    if (fd < 0 || close(fd)) {
+    if (fd < 0) {
+        fprintf(stderr, "Could not create temporary snapshot in %s directory: "
+                "%s\n", tmpdir, strerror(errno));
+        return -errno;
+    }
+    if (close(fd) != 0) {
         return -errno;
     }
     return 0;
-- 
1.7.12