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[v6,13/22] block: Don't lock drive-backup target image in none mode

Message ID 1464943756-14143-14-git-send-email-famz@redhat.com
State New
Headers show

Commit Message

Fam Zheng June 3, 2016, 8:49 a.m. UTC 
As a very special case, in sync=none mode, the source is the backing image of
the target, which will be RO opened again. This won't work with image locking
because the first open could be exclusive.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 blockdev.c | 5 +++++
 1 file changed, 5 insertions(+)
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Patch

diff --git a/blockdev.c b/blockdev.c
index 5acb286..fa8b50c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3256,6 +3256,11 @@  static void do_drive_backup(const char *device, const char *target,
         }
     }
     if (sync == MIRROR_SYNC_MODE_NONE) {
+        /* XXX: bs will be open second time as the backing file of target,
+         * disable image locking. Once block layer allows sharing backing BDS,
+         * change below to BDRV_O_NO_BACKING and assign it after bdrv_open().
+         **/
+        flags |= BDRV_O_NO_LOCK;
         source = bs;
     }