[Qemu-devel] [PATCH v3 0/2] block: fix spurious DEVICE_TRAY_MOVED events on shutdown

[Qemu-devel] [PATCH v3 0/2] block: fix spurious DEVICE_TRAY_MOVED events on shutdown

[Pavel Hrdina]

This fixes a regression introduced by commit 9ca111544.

The first commit is done by Luiz and I've just use it as it is.

The second commit moves the bdrv_dev_change_media_cb() into eject_device(),
called by QMP and HMP eject command, and into qmp_bdrv_open_encrypted(),
called by QMP and HMP change command. These are the only place where I think
that should call the bdrv_dev_change_media_cb() function.

There is no reason to call this function while we are removing the device
from the guest, for example while closing and deleting all devices on shutdown.

* changes from v1:
    - used the first patch from Luiz's series

* changes from v2:
    - added comment that the error QERR_DEVICE_NOT_ENCRYPTED is used as warning

Luiz Capitulino (1):
  block: make bdrv_dev_change_media_cb() public

Pavel Hrdina (1):
  block: move the bdrv_dev_change_media_cb()

 block.c               | 11 +----------
 blockdev.c            |  7 +++++++
 include/block/block.h |  1 +
 3 files changed, 9 insertions(+), 10 deletions(-)

-- 
1.8.1.4

[Qemu-devel] [PATCH v3 1/2] block: make bdrv_dev_change_media_cb() public

[Pavel Hrdina]

From: Luiz Capitulino <lcapitulino@redhat.com>

Next commit wants to use it.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 block.c               | 3 +--
 include/block/block.h | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index 79ad33d..9fbaf1a 100644
--- a/block.c
+++ b/block.c
@@ -56,7 +56,6 @@ typedef enum {
     BDRV_REQ_ZERO_WRITE   = 0x2,
 } BdrvRequestFlags;
 
-static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
 static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
         BlockDriverCompletionFunc *cb, void *opaque);
@@ -1682,7 +1681,7 @@ static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected)
     qobject_decref(data);
 }
 
-static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
+void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
 {
     if (bs->dev_ops && bs->dev_ops->change_media_cb) {
         bool tray_was_closed = !bdrv_dev_is_tray_open(bs);
diff --git a/include/block/block.h b/include/block/block.h
index 2307f67..2cc93ab 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -148,6 +148,7 @@ void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
                       void *opaque);
 void bdrv_dev_eject_request(BlockDriverState *bs, bool force);
 bool bdrv_dev_has_removable_media(BlockDriverState *bs);
+void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
 bool bdrv_dev_is_tray_open(BlockDriverState *bs);
 bool bdrv_dev_is_medium_locked(BlockDriverState *bs);
 int bdrv_read(BlockDriverState *bs, int64_t sector_num,
-- 
1.8.1.4

[Qemu-devel] [PATCH v3 2/2] block: move the bdrv_dev_change_media_cb()

[Pavel Hrdina]

The bdrv_dev_change_media_cb() should be called only for eject and change
commands. We should call that function only if that command is successful.

What this function does is that it calls the change_media_cb() and also emit
the QEVENT_DEVICE_TRAY_MOVED event.

If a password is not required, but user provides some, the error is used as
warning.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 block.c    | 8 --------
 blockdev.c | 7 +++++++
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/block.c b/block.c
index 9fbaf1a..0411c85 100644
--- a/block.c
+++ b/block.c
@@ -1092,10 +1092,6 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
     }
     QDECREF(options);
 
-    if (!bdrv_key_required(bs)) {
-        bdrv_dev_change_media_cb(bs, true);
-    }
-
     /* throttling disk I/O limits */
     if (bs->io_limits_enabled) {
         bdrv_io_limits_enable(bs);
@@ -1394,8 +1390,6 @@ void bdrv_close(BlockDriverState *bs)
         }
     }
 
-    bdrv_dev_change_media_cb(bs, false);
-
     /*throttling disk I/O limits*/
     if (bs->io_limits_enabled) {
         bdrv_io_limits_disable(bs);
@@ -2846,8 +2840,6 @@ int bdrv_set_key(BlockDriverState *bs, const char *key)
         bs->valid_key = 0;
     } else if (!bs->valid_key) {
         bs->valid_key = 1;
-        /* call the change callback now, we skipped it on open */
-        bdrv_dev_change_media_cb(bs, true);
     }
     return ret;
 }
diff --git a/blockdev.c b/blockdev.c
index 9937311..3498413 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1022,6 +1022,7 @@ static void eject_device(BlockDriverState *bs, int force, Error **errp)
     }
 
     bdrv_close(bs);
+    bdrv_dev_change_media_cb(bs, false);
 }
 
 void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
@@ -1071,14 +1072,20 @@ static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
         if (password) {
             if (bdrv_set_key(bs, password) < 0) {
                 error_set(errp, QERR_INVALID_PASSWORD);
+                return;
             }
         } else {
             error_set(errp, QERR_DEVICE_ENCRYPTED, bdrv_get_device_name(bs),
                       bdrv_get_encrypted_filename(bs));
+            return;
         }
     } else if (password) {
+        /* This is only warning that you shoud not use a password for not
+         * encrypted device. */
         error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
     }
+
+    bdrv_dev_change_media_cb(bs, true);
 }
 
 void qmp_change_blockdev(const char *device, const char *filename,
-- 
1.8.1.4

Re: [Qemu-devel] [PATCH v3 2/2] block: move the bdrv_dev_change_media_cb()

[Stefan Hajnoczi]

On Mon, Jun 17, 2013 at 03:21:41PM +0200, Pavel Hrdina wrote:
> The bdrv_dev_change_media_cb() should be called only for eject and change
> commands. We should call that function only if that command is successful.
> 
> What this function does is that it calls the change_media_cb() and also emit
> the QEVENT_DEVICE_TRAY_MOVED event.
> 
> If a password is not required, but user provides some, the error is used as
> warning.
> 
> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
> ---
>  block.c    | 8 --------
>  blockdev.c | 7 +++++++
>  2 files changed, 7 insertions(+), 8 deletions(-)

This commit description explains what the code changes do but it doesn't
explain why.  The cover letter mentions a regression without going into
detail, and that will not be commited to git.  Please add information
about the regression that this patch fixes so the git history has enough
information to justify this patch.

Markus posted a list of places that are affected by this change.  Have
you worked through them to show this patch is safe?

Stefan

Re: [Qemu-devel] [PATCH v3 2/2] block: move the bdrv_dev_change_media_cb()

[Pavel Hrdina]

On 19.6.2013 12:16, Stefan Hajnoczi wrote:
> On Mon, Jun 17, 2013 at 03:21:41PM +0200, Pavel Hrdina wrote:
>> The bdrv_dev_change_media_cb() should be called only for eject and change
>> commands. We should call that function only if that command is successful.
>>
>> What this function does is that it calls the change_media_cb() and also emit
>> the QEVENT_DEVICE_TRAY_MOVED event.
>>
>> If a password is not required, but user provides some, the error is used as
>> warning.
>>
>> Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
>> ---
>>   block.c    | 8 --------
>>   blockdev.c | 7 +++++++
>>   2 files changed, 7 insertions(+), 8 deletions(-)
>
> This commit description explains what the code changes do but it doesn't
> explain why.  The cover letter mentions a regression without going into
> detail, and that will not be commited to git.  Please add information
> about the regression that this patch fixes so the git history has enough
> information to justify this patch.

Thanks, I explain this change directly in the commit message.

>
> Markus posted a list of places that are affected by this change.  Have
> you worked through them to show this patch is safe?

Today I've checked hopefully all possible ways how to get into the
'bdrv_dev_change_media_cb()' regarding Markus' comment.

The only relevant callers are the qmp_change and qmp_eject because
the purpose of the 'bdrv_dev_change_media_cb()' is to call the
devices' handlers for change media event, update the tray status
and also emit the DEVICE_TRAY_MOVED event.

Pavel

>
> Stefan
>