diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 27 |
1 files changed, 23 insertions, 4 deletions
@@ -845,18 +845,33 @@ fail: return ret; } -int bdrv_open_backing_file(BlockDriverState *bs) +/* + * Opens the backing file for a BlockDriverState if not yet open + * + * options is a QDict of options to pass to the block drivers, or NULL for an + * empty set of options. The reference to the QDict is transferred to this + * function (even on failure), so if the caller intends to reuse the dictionary, + * it needs to use QINCREF() before calling bdrv_file_open. + */ +int bdrv_open_backing_file(BlockDriverState *bs, QDict *options) { char backing_filename[PATH_MAX]; int back_flags, ret; BlockDriver *back_drv = NULL; if (bs->backing_hd != NULL) { + QDECREF(options); return 0; } + /* NULL means an empty set of options */ + if (options == NULL) { + options = qdict_new(); + } + bs->open_flags &= ~BDRV_O_NO_BACKING; - if (bs->backing_file[0] == '\0') { + if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) { + QDECREF(options); return 0; } @@ -871,7 +886,8 @@ int bdrv_open_backing_file(BlockDriverState *bs) /* 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, NULL, + ret = bdrv_open(bs->backing_hd, + *backing_filename ? backing_filename : NULL, options, back_flags, back_drv); if (ret < 0) { bdrv_delete(bs->backing_hd); @@ -1027,7 +1043,10 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options, /* If there is a backing file, use it */ if ((flags & BDRV_O_NO_BACKING) == 0) { - ret = bdrv_open_backing_file(bs); + QDict *backing_options; + + extract_subqdict(options, &backing_options, "backing."); + ret = bdrv_open_backing_file(bs, backing_options); if (ret < 0) { goto close_and_fail; } |