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authorKevin Wolf <kwolf@redhat.com>2010-10-21 16:43:43 +0200
committerKevin Wolf <kwolf@redhat.com>2010-11-04 12:52:16 +0100
commit205ef7961f781496366e0a93a4ec621ad3724bd7 (patch)
tree7c1861837185ba98074140dba8f03e65941c8c8c /block.c
parent5dba48a882c126ccc86db6506cfa6dcca97badab (diff)
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block: Allow bdrv_flush to return errors
This changes bdrv_flush to return 0 on success and -errno in case of failure. It's a requirement for implementing proper error handle in users of bdrv_flush. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Diffstat (limited to 'block.c')
-rw-r--r--block.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/block.c b/block.c
index 985d0b7..6b505fb 100644
--- a/block.c
+++ b/block.c
@@ -1453,14 +1453,27 @@ const char *bdrv_get_device_name(BlockDriverState *bs)
return bs->device_name;
}
-void bdrv_flush(BlockDriverState *bs)
+int bdrv_flush(BlockDriverState *bs)
{
if (bs->open_flags & BDRV_O_NO_FLUSH) {
- return;
+ return 0;
+ }
+
+ if (bs->drv && bs->drv->bdrv_flush) {
+ return bs->drv->bdrv_flush(bs);
}
- if (bs->drv && bs->drv->bdrv_flush)
- bs->drv->bdrv_flush(bs);
+ /*
+ * Some block drivers always operate in either writethrough or unsafe mode
+ * and don't support bdrv_flush therefore. Usually qemu doesn't know how
+ * the server works (because the behaviour is hardcoded or depends on
+ * server-side configuration), so we can't ensure that everything is safe
+ * on disk. Returning an error doesn't work because that would break guests
+ * even if the server operates in writethrough mode.
+ *
+ * Let's hope the user knows what he's doing.
+ */
+ return 0;
}
void bdrv_flush_all(void)