[Qemu-devel] [PATCH 2/4] blockdev: Fix 'change' for slot devices

[Max Reitz]

'change' and related operations did not work when used on guest devices
featuring removable media but no actual tray, because
blk_dev_is_tray_open() always returned false for them and the
blockdev-{insert,remove}-medium commands required it to return true.

Fix this by making blockdev-{insert,remove}-medium work on tray-less
devices. Also, blockdev-{open,close}-tray are now explicitly no-ops when
invoked on such devices, and blk_dev_change_media_cb() is instead
called by blockdev-{insert,remove}-medium (for tray-less devices only).

Reported-by: Peter Maydell <peter.mayd...@linaro.org>
Cc: qemu-stable <qemu-sta...@nongnu.org>
Signed-off-by: Max Reitz <mre...@redhat.com>
---
 blockdev.c           | 27 +++++++++++++++++++++++++--
 qapi/block-core.json |  3 +--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 2df0c6d..f053be6 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2305,6 +2305,11 @@ void qmp_blockdev_open_tray(const char *device, bool 
has_force, bool force,
         return;
     }
 
+    if (!blk_dev_has_tray(blk)) {
+        /* Ignore this command on tray-less devices */
+        return;
+    }
+
     if (blk_dev_is_tray_open(blk)) {
         return;
     }
@@ -2335,6 +2340,11 @@ void qmp_blockdev_close_tray(const char *device, Error 
**errp)
         return;
     }
 
+    if (!blk_dev_has_tray(blk)) {
+        /* Ignore this command on tray-less devices */
+        return;
+    }
+
     if (!blk_dev_is_tray_open(blk)) {
         return;
     }
@@ -2364,7 +2374,7 @@ void qmp_x_blockdev_remove_medium(const char *device, 
Error **errp)
         return;
     }
 
-    if (has_device && !blk_dev_is_tray_open(blk)) {
+    if (has_device && blk_dev_has_tray(blk) && !blk_dev_is_tray_open(blk)) {
         error_setg(errp, "Tray of device '%s' is not open", device);
         return;
     }
@@ -2381,6 +2391,12 @@ void qmp_x_blockdev_remove_medium(const char *device, 
Error **errp)
         goto out;
     }
 
+    if (!blk_dev_has_tray(blk)) {
+        /* For tray-less devices, blockdev-open-tray is a no-op (or may not be
+         * called at all); therefore, the medium needs to be ejected here */
+        blk_dev_change_media_cb(blk, false);
+    }
+
     /* This follows the convention established by bdrv_make_anon() */
     if (bs->device_list.tqe_prev) {
         QTAILQ_REMOVE(&bdrv_states, bs, device_list);
@@ -2414,7 +2430,7 @@ static void qmp_blockdev_insert_anon_medium(const char 
*device,
         return;
     }
 
-    if (has_device && !blk_dev_is_tray_open(blk)) {
+    if (has_device && blk_dev_has_tray(blk) && !blk_dev_is_tray_open(blk)) {
         error_setg(errp, "Tray of device '%s' is not open", device);
         return;
     }
@@ -2424,6 +2440,13 @@ static void qmp_blockdev_insert_anon_medium(const char 
*device,
         return;
     }
 
+    if (!blk_dev_has_tray(blk)) {
+        /* For tray-less devices, blockdev-close-tray is a no-op (or may not be
+         * called at all); therefore, the medium needs to be pushed into the
+         * slot here */
+        blk_dev_change_media_cb(blk, true);
+    }
+
     blk_insert_bs(blk, bs);
 
     QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 0a915ed..40239bf 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2098,8 +2098,7 @@
 #   respond to the eject request
 # - if the BlockBackend denoted by @device does not have a guest device 
attached
 #   to it
-# - if the guest device does not have an actual tray and is empty, for instance
-#   for floppy disk drives
+# - if the guest device does not have an actual tray
 #
 # @device: block device name
 #
-- 
2.7.0