[Qemu-devel] [PATCH v3] 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>
---
v1 -> v2:
   Output error message only if fd < 0
v2 -> v3:
   Output error message in the caller of get_tmp_filename()
 block.c | 2 ++
 1 个文件被修改，插入 2 行(+)

diff --git a/block.c b/block.c
index 470bdcc..074987e 100644
--- a/block.c
+++ b/block.c
@@ -764,6 +764,8 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
 
         ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
         if (ret < 0) {
+            fprintf(stderr, "Could not create temporary snapshot %s: %s\n",
+                    tmp_filename, strerror(errno));
             return ret;
         }
 
-- 
1.7.12