From b1a86eb532b4d32e4527a5373307873d95729aea Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 18 Apr 2014 15:44:19 +0200 Subject: [PATCH] block: Use BDRV_O_NO_BACKING where appropriate If you open an image temporarily just because you want to check its size or get it flushed, there's no real reason to open the whole backing file chain. This is a backport of c9fbb99d41b05acf0d7b93deb2fcdbf9047c238e to qemu 1.7.1. The backport was done to fix a bug where QEMU 1.7.1 would crash or freeze when the user take around 80 consecutives snapshots in a row. git bisect would lead to commit: ba2ab2f2ca4150a7e314fbb19fa158bd8ddc36eb and it was clear that BDRV_NO_BACKING was missing. Signed-off-by: Kevin Wolf Signed-off-by: Benoit Canet Signed-off-by: Michael Roth --- block.c | 4 ++-- block/qcow2.c | 3 ++- block/vmdk.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/block.c b/block.c index 8f84dbc5cb..68651a9ba4 100644 --- a/block.c +++ b/block.c @@ -1067,9 +1067,9 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options, /* if snapshot, we create a temporary backing file and open it instead of opening 'filename' directly */ - /* if there is a backing file, use it */ bs1 = bdrv_new(""); - ret = bdrv_open(bs1, filename, NULL, 0, drv, &local_err); + ret = bdrv_open(bs1, filename, NULL, BDRV_O_NO_BACKING, drv, + &local_err); if (ret < 0) { bdrv_unref(bs1); goto fail; diff --git a/block/qcow2.c b/block/qcow2.c index b43c7d0a3e..f2897b64aa 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1605,7 +1605,8 @@ static int qcow2_create2(const char *filename, int64_t total_size, /* Reopen the image without BDRV_O_NO_FLUSH to flush it before returning */ ret = bdrv_open(bs, filename, NULL, - BDRV_O_RDWR | BDRV_O_CACHE_WB, drv, &local_err); + BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_BACKING, + drv, &local_err); if (error_is_set(&local_err)) { error_propagate(errp, local_err); goto out; diff --git a/block/vmdk.c b/block/vmdk.c index a7ebd0f125..d35a9d7e02 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -1689,7 +1689,7 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options, } if (backing_file) { BlockDriverState *bs = bdrv_new(""); - ret = bdrv_open(bs, backing_file, NULL, 0, NULL, errp); + ret = bdrv_open(bs, backing_file, NULL, BDRV_O_NO_BACKING, NULL, errp); if (ret != 0) { bdrv_unref(bs); return ret;