[PATCH 3/3] block: switch to use qemu_open_err for improved errors

["Daniel P. Berrangé" <berrange@redhat.com>]

Currently at startup if using cache=none on a filesystem lacking
O_DIRECT such as tmpfs, at startup QEMU prints

qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: file system may not support O_DIRECT
qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Could not open '/tmp/foo.img': Invalid argument

while at QMP level the hint is missing, so QEMU reports just

  "error": {
      "class": "GenericError",
      "desc": "Could not open '/tmp/foo.img': Invalid argument"
  }

which is close to useless for the end user trying to figure out what
they did wrong

With this change at startup QEMU prints

qemu-system-x86_64: -drive file=/tmp/foo.img,cache=none: Unable to open '/tmp/foo.img' flags 0x4000: filesystem does not support O_DIRECT

while at the QMP level QEMU reports a massively more informative

  "error": {
     "class": "GenericError",
     "desc": "Unable to open '/tmp/foo.img' flags 0x4002: filesystem does not support O_DIRECT"
  }

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 block/file-posix.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 3ab8f5a0fa..2865b789fb 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -574,11 +574,10 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     raw_parse_flags(bdrv_flags, &s->open_flags, false);
 
     s->fd = -1;
-    fd = qemu_open(filename, s->open_flags, 0644);
+    fd = qemu_open_err(filename, s->open_flags, errp, 0644);
     ret = fd < 0 ? -errno : 0;
 
     if (ret < 0) {
-        error_setg_file_open(errp, -ret, filename);
         if (ret == -EROFS) {
             ret = -EACCES;
         }
@@ -970,9 +969,8 @@ static int raw_reconfigure_getfd(BlockDriverState *bs, int flags,
         ret = raw_normalize_devicepath(&normalized_filename, errp);
         if (ret >= 0) {
             assert(!(*open_flags & O_CREAT));
-            fd = qemu_open(normalized_filename, *open_flags);
+            fd = qemu_open_err(normalized_filename, *open_flags, errp);
             if (fd == -1) {
-                error_setg_errno(errp, errno, "Could not reopen file");
                 return -1;
             }
         }
@@ -2324,10 +2322,10 @@ raw_co_create(BlockdevCreateOptions *options, Error **errp)
     }
 
     /* Create file */
-    fd = qemu_open(file_opts->filename, O_RDWR | O_CREAT | O_BINARY, 0644);
+    fd = qemu_open_err(file_opts->filename, O_RDWR | O_CREAT | O_BINARY,
+                       errp, 0644);
     if (fd < 0) {
         result = -errno;
-        error_setg_errno(errp, -result, "Could not create file");
         goto out;
     }
 
-- 
2.26.2