[Qemu-devel] [PATCH 3/10] Add bdrv_flush_all()

[Anthony Liguori <aliguori@us.ibm.com>]

This patch adds a bdrv_flush_all() function.  It's necessary to ensure that all
IO operations have been flushed to disk before completely a live migration.

N.B. we don't actually use this now.  We really should flush the block drivers
using an live savevm callback to avoid unnecessary guest down time.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/block.c b/block.c
index 544176f..921d382 100644
--- a/block.c
+++ b/block.c
@@ -884,6 +884,21 @@ void bdrv_flush(BlockDriverState *bs)
         bdrv_flush(bs->backing_hd);
 }
 
+void bdrv_iterate_writeable(void (*it)(BlockDriverState *bs))
+{
+    BlockDriverState *bs;
+
+    for (bs = bdrv_first; bs != NULL; bs = bs->next)
+        if (bs->drv && !bdrv_is_read_only(bs) && 
+            (!bdrv_is_removable(bs) || bdrv_is_inserted(bs)))
+	    it(bs);
+}
+
+void bdrv_flush_all(void)
+{
+    bdrv_iterate_writeable(bdrv_flush);
+}
+
 /*
  * Returns true iff the specified sector is present in the disk image. Drivers
  * not implementing the functionality are assumed to not support backing files,
diff --git a/block.h b/block.h
index fa741b5..8586dc1 100644
--- a/block.h
+++ b/block.h
@@ -112,6 +112,8 @@ int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
 #define BIOS_ATA_TRANSLATION_LARGE  3
 #define BIOS_ATA_TRANSLATION_RECHS  4
 
+void bdrv_flush_all(void);
+
 void bdrv_set_geometry_hint(BlockDriverState *bs,
                             int cyls, int heads, int secs);
 void bdrv_set_type_hint(BlockDriverState *bs, int type);