diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 56 |
1 files changed, 38 insertions, 18 deletions
@@ -736,6 +736,42 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags) return 0; } +int bdrv_open_backing_file(BlockDriverState *bs) +{ + char backing_filename[PATH_MAX]; + int back_flags, ret; + BlockDriver *back_drv = NULL; + + if (bs->backing_hd != NULL) { + return 0; + } + + bs->open_flags &= ~BDRV_O_NO_BACKING; + if (bs->backing_file[0] == '\0') { + return 0; + } + + bs->backing_hd = bdrv_new(""); + bdrv_get_full_backing_filename(bs, backing_filename, + sizeof(backing_filename)); + + if (bs->backing_format[0] != '\0') { + 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); + + ret = bdrv_open(bs->backing_hd, backing_filename, back_flags, back_drv); + if (ret < 0) { + bdrv_delete(bs->backing_hd); + bs->backing_hd = NULL; + bs->open_flags |= BDRV_O_NO_BACKING; + return ret; + } + return 0; +} + /* * Opens a disk image (raw, qcow2, vmdk, ...) */ @@ -823,24 +859,8 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, } /* If there is a backing file, use it */ - if ((flags & BDRV_O_NO_BACKING) == 0 && bs->backing_file[0] != '\0') { - char backing_filename[PATH_MAX]; - int back_flags; - BlockDriver *back_drv = NULL; - - bs->backing_hd = bdrv_new(""); - bdrv_get_full_backing_filename(bs, backing_filename, - sizeof(backing_filename)); - - if (bs->backing_format[0] != '\0') { - back_drv = bdrv_find_format(bs->backing_format); - } - - /* backing files always opened read-only */ - back_flags = - flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING); - - ret = bdrv_open(bs->backing_hd, backing_filename, back_flags, back_drv); + if ((flags & BDRV_O_NO_BACKING) == 0) { + ret = bdrv_open_backing_file(bs); if (ret < 0) { bdrv_close(bs); return ret; |