[Qemu-devel] [PATCH 13/12] block: add close notifiers

[Paolo Bonzini <pbonzini@redhat.com>]

The first user of close notifiers will be the embedded NBD server.
It is possible to use them to do some of the ad hoc processing
(e.g. for block jobs and I/O limits) that is currently done by
bdrv_close.

Acked-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 Makefile.objs |  3 ++-
 block.c       | 19 ++++++++++++++-----
 block.h       |  1 +
 block_int.h   |  2 ++
 4 file modificati, 19 inserzioni(+), 6 rimozioni(-)

diff --git a/Makefile.objs b/Makefile.objs
index 03da150..124f783 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -43,6 +43,7 @@ coroutine-obj-$(CONFIG_WIN32) += coroutine-win32.o
 
 block-obj-y = cutils.o iov.o cache-utils.o qemu-option.o module.o async.o
 block-obj-y += nbd.o block.o aio.o aes.o qemu-config.o qemu-progress.o qemu-sockets.o
+block-obj-y += notify.o
 block-obj-y += $(coroutine-obj-y) $(qobject-obj-y) $(version-obj-y)
 block-obj-$(CONFIG_POSIX) += posix-aio-compat.o
 block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
@@ -92,7 +93,7 @@ common-obj-y += bt-host.o bt-vhci.o
 
 common-obj-y += iov.o acl.o
 common-obj-$(CONFIG_POSIX) += compatfd.o
-common-obj-y += notify.o event_notifier.o
+common-obj-y += event_notifier.o
 common-obj-y += qemu-timer.o qemu-timer-common.o
 
 common-obj-$(CONFIG_SLIRP) += slirp/
diff --git a/block.c b/block.c
index 470bdcc..cb44dac 100644
--- a/block.c
+++ b/block.c
@@ -28,6 +28,7 @@
 #include "block_int.h"
 #include "module.h"
 #include "qjson.h"
+#include "notify.h"
 #include "qemu-coroutine.h"
 #include "qmp-commands.h"
 #include "qemu-timer.h"
@@ -310,9 +311,16 @@ BlockDriverState *bdrv_new(const char *device_name)
         QTAILQ_INSERT_TAIL(&bdrv_states, bs, list);
     }
     bdrv_iostatus_disable(bs);
+    notifier_list_init(&bs->close_notifiers);
+
     return bs;
 }
 
+void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify)
+{
+    notifier_list_add(&bs->close_notifiers, notify);
+}
+
 BlockDriver *bdrv_find_format(const char *format_name)
 {
     BlockDriver *drv1;
@@ -862,12 +870,13 @@ unlink_and_fail:
 void bdrv_close(BlockDriverState *bs)
 {
     bdrv_flush(bs);
-    if (bs->drv) {
-        if (bs->job) {
-            block_job_cancel_sync(bs->job);
-        }
-        bdrv_drain_all();
+    if (bs->job) {
+        block_job_cancel_sync(bs->job);
+    }
+    bdrv_drain_all();
+    notifier_list_notify(&bs->close_notifiers, bs);
 
+    if (bs->drv) {
         if (bs == bs_snapshots) {
             bs_snapshots = NULL;
         }
diff --git a/block.h b/block.h
index 2e2be11..921c72e 100644
--- a/block.h
+++ b/block.h
@@ -131,6 +131,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags);
 int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
               BlockDriver *drv);
 void bdrv_close(BlockDriverState *bs);
+void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify);
 int bdrv_attach_dev(BlockDriverState *bs, void *dev);
 void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev);
 void bdrv_detach_dev(BlockDriverState *bs, void *dev);
diff --git a/block_int.h b/block_int.h
index 4452f6f..4eb79c2 100644
--- a/block_int.h
+++ b/block_int.h
@@ -293,6 +293,8 @@ struct BlockDriverState {
     BlockDriverState *backing_hd;
     BlockDriverState *file;
 
+    NotifierList close_notifiers;
+
     /* number of in-flight copy-on-read requests */
     unsigned int copy_on_read_in_flight;
 
-- 
1.7.12