diff options
| -rw-r--r-- | block.c | 23 |
1 files changed, 17 insertions, 6 deletions
@@ -798,6 +798,21 @@ static int bdrv_inherited_flags(int flags) return flags; } +/* + * Returns the flags that bs->backing_hd should get, based on the given flags + * for the parent BDS + */ +static int bdrv_backing_flags(int flags) +{ + /* backing files always opened read-only */ + flags &= ~(BDRV_O_RDWR | BDRV_O_COPY_ON_READ); + + /* snapshot=on is handled on the top layer */ + flags &= ~BDRV_O_SNAPSHOT; + + return flags; +} + static int bdrv_open_flags(BlockDriverState *bs, int flags) { int open_flags = flags | BDRV_O_CACHE_WB; @@ -1093,7 +1108,7 @@ fail: int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) { char *backing_filename = g_malloc0(PATH_MAX); - int back_flags, ret = 0; + int ret = 0; BlockDriver *back_drv = NULL; Error *local_err = NULL; @@ -1121,14 +1136,10 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp) back_drv = bdrv_find_format(bs->backing_format); } - /* backing files always opened read-only */ - back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | - BDRV_O_COPY_ON_READ); - assert(bs->backing_hd == NULL); ret = bdrv_open(&bs->backing_hd, *backing_filename ? backing_filename : NULL, NULL, options, - back_flags, back_drv, &local_err); + bdrv_backing_flags(bs->open_flags), back_drv, &local_err); if (ret < 0) { bs->backing_hd = NULL; bs->open_flags |= BDRV_O_NO_BACKING; |