From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46512) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b2ZXN-00075x-FI for qemu-devel@nongnu.org; Tue, 17 May 2016 03:35:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b2ZXL-0003hC-FU for qemu-devel@nongnu.org; Tue, 17 May 2016 03:35:28 -0400 From: Fam Zheng Date: Tue, 17 May 2016 15:35:10 +0800 Message-Id: <1463470536-8981-2-git-send-email-famz@redhat.com> In-Reply-To: <1463470536-8981-1-git-send-email-famz@redhat.com> References: <1463470536-8981-1-git-send-email-famz@redhat.com> Subject: [Qemu-devel] [PATCH v5 01/27] block: Add flag bits for image locking List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Max Reitz , Jeff Cody , Markus Armbruster , Eric Blake , John Snow , qemu-block@nongnu.org, berrange@redhat.com, pbonzini@redhat.com, den@openvz.org, stefanha@redhat.com Later the block layer will automatically lock the images to avoid unexpected concurrent accesses to the same image, which will easily corrupt the metadata or user data, unless in some very special cases, like migration. The exceptional cases like shared storage migration and testing should set BDRV_O_SHARED_LOCK or BDRV_O_NO_LOCK to advise an appropriate locking mode. Signed-off-by: Fam Zheng --- include/block/block.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/block/block.h b/include/block/block.h index b210832..14f7300 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -94,6 +94,8 @@ typedef struct HDGeometry { select an appropriate protocol driver, ignoring the format layer */ #define BDRV_O_NO_IO 0x10000 /* don't initialize for I/O */ +#define BDRV_O_NO_LOCK 0x20000 /* don't lock image file */ +#define BDRV_O_SHARED_LOCK 0x40000 /* lock the image file in shared mode */ #define BDRV_O_CACHE_MASK (BDRV_O_NOCACHE | BDRV_O_NO_FLUSH) -- 2.8.2