[Qemu-block] [PATCH] block: clarify error message for qmp-eject

[John Snow]

If you use HMP's eject but the CDROM tray is locked, you may get a
confusing error message informing you that the "tray isn't open."

As this is the point of eject, we can do a little better and help
clarify that the tray was locked and that it (might) open up later,
so try again.

It's not ideal, but it makes the semantics of the (legacy) eject
command more understandable to end users when they try to use it.

Signed-off-by: John Snow <address@hidden>
---
 blockdev.c | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 1892b8e..feb8484 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2290,16 +2290,26 @@ exit:
     block_job_txn_unref(block_job_txn);
 }
 
+static int do_open_tray(const char *device, bool has_force, bool force,
+                        Error **errp);
+
 void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
 {
     Error *local_err = NULL;
+    int rc;
 
-    qmp_blockdev_open_tray(device, has_force, force, &local_err);
+    rc = do_open_tray(device, has_force, force, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
     }
 
+    if (rc == -EINPROGRESS) {
+        error_setg(errp, "Device '%s' is locked and force was not specified, "
+                   "wait for tray to open and try again", device);
+        return;
+    }
+
     qmp_x_blockdev_remove_medium(device, errp);
 }
 
@@ -2327,8 +2337,8 @@ void qmp_block_passwd(bool has_device, const char *device,
     aio_context_release(aio_context);
 }
 
-void qmp_blockdev_open_tray(const char *device, bool has_force, bool force,
-                            Error **errp)
+static int do_open_tray(const char *device, bool has_force, bool force,
+                        Error **errp)
 {
     BlockBackend *blk;
     bool locked;
@@ -2341,21 +2351,21 @@ void qmp_blockdev_open_tray(const char *device, bool 
has_force, bool force,
     if (!blk) {
         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
                   "Device '%s' not found", device);
-        return;
+        return -ENODEV;
     }
 
     if (!blk_dev_has_removable_media(blk)) {
         error_setg(errp, "Device '%s' is not removable", device);
-        return;
+        return -ENOTSUP;
     }
 
     if (!blk_dev_has_tray(blk)) {
         /* Ignore this command on tray-less devices */
-        return;
+        return -ENOSYS;
     }
 
     if (blk_dev_is_tray_open(blk)) {
-        return;
+        return 0;
     }
 
     locked = blk_dev_is_medium_locked(blk);
@@ -2366,6 +2376,18 @@ void qmp_blockdev_open_tray(const char *device, bool 
has_force, bool force,
     if (!locked || force) {
         blk_dev_change_media_cb(blk, false);
     }
+
+    if (locked && !force) {
+        return -EINPROGRESS;
+    }
+
+    return 0;
+}
+
+void qmp_blockdev_open_tray(const char *device, bool has_force, bool force,
+                            Error **errp)
+{
+    do_open_tray(device, has_force, force, errp);
 }
 
 void qmp_blockdev_close_tray(const char *device, Error **errp)
-- 
2.4.11