Patchwork [2/5] blockdev: add refcount to DriveInfo

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Submitter Marcelo Tosatti
Date Jan. 26, 2011, 2:12 p.m.
Message ID <20110126141348.224787741@redhat.com>
Download mbox | patch
Permalink /patch/80513/
State New
Headers show

Comments

Marcelo Tosatti - Jan. 26, 2011, 2:12 p.m.
The host part of a block device can be deleted with in progress
block migration.

To fix this, add a reference count to DriveInfo, freeing resources
on last reference.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>

Patch

Index: qemu/blockdev.c
===================================================================
--- qemu.orig/blockdev.c
+++ qemu/blockdev.c
@@ -40,7 +40,7 @@  void blockdev_auto_del(BlockDriverState 
     DriveInfo *dinfo = drive_get_by_blockdev(bs);
 
     if (dinfo && dinfo->auto_del) {
-        drive_uninit(dinfo);
+        drive_put_ref(dinfo);
     }
 }
 
@@ -110,7 +110,7 @@  static void bdrv_format_print(void *opaq
     fprintf(stderr, " %s", name);
 }
 
-void drive_uninit(DriveInfo *dinfo)
+static void drive_uninit(DriveInfo *dinfo)
 {
     qemu_opts_del(dinfo->opts);
     bdrv_delete(dinfo->bdrv);
@@ -118,6 +118,19 @@  void drive_uninit(DriveInfo *dinfo)
     qemu_free(dinfo);
 }
 
+void drive_put_ref(DriveInfo *dinfo)
+{
+    assert(dinfo->refcount);
+    if (--dinfo->refcount == 0) {
+        drive_uninit(dinfo);
+    }
+}
+
+void drive_get_ref(DriveInfo *dinfo)
+{
+    dinfo->refcount++;
+}
+
 static int parse_block_error_action(const char *buf, int is_read)
 {
     if (!strcmp(buf, "ignore")) {
@@ -421,6 +434,7 @@  DriveInfo *drive_init(QemuOpts *opts, in
     dinfo->bus = bus_id;
     dinfo->unit = unit_id;
     dinfo->opts = opts;
+    dinfo->refcount = 1;
     if (serial)
         strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
     QTAILQ_INSERT_TAIL(&drives, dinfo, next);
Index: qemu/blockdev.h
===================================================================
--- qemu.orig/blockdev.h
+++ qemu/blockdev.h
@@ -29,6 +29,7 @@  struct DriveInfo {
     QemuOpts *opts;
     char serial[BLOCK_SERIAL_STRLEN + 1];
     QTAILQ_ENTRY(DriveInfo) next;
+    int refcount;
 };
 
 #define MAX_IDE_DEVS	2
@@ -36,7 +37,8 @@  struct DriveInfo {
 
 DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit);
 int drive_get_max_bus(BlockInterfaceType type);
-void drive_uninit(DriveInfo *dinfo);
+void drive_get_ref(DriveInfo *dinfo);
+void drive_put_ref(DriveInfo *dinfo);
 DriveInfo *drive_get_by_blockdev(BlockDriverState *bs);
 
 QemuOpts *drive_add(const char *file, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
Index: qemu/hw/pci-hotplug.c
===================================================================
--- qemu.orig/hw/pci-hotplug.c
+++ qemu/hw/pci-hotplug.c
@@ -146,7 +146,7 @@  void drive_hot_add(Monitor *mon, const Q
 
 err:
     if (dinfo)
-        drive_uninit(dinfo);
+        drive_put_ref(dinfo);
     return;
 }