@@ -496,6 +496,7 @@ char *bdrv_get_full_backing_filename(BlockDriverState *bs, Error **errp);
char *bdrv_get_full_backing_filename_from_filename(const char *backed,
const char *backing,
Error **errp);
+char *bdrv_dirname(BlockDriverState *bs, Error **errp);
int path_has_protocol(const char *path);
int path_is_absolute(const char *path);
@@ -131,6 +131,13 @@ struct BlockDriver {
void (*bdrv_refresh_filename)(BlockDriverState *bs, QDict *options);
+ /*
+ * Returns an allocated string which is the directory name of this BDS: It
+ * will be used to make relative filenames absolute by prepending this
+ * function's return value to them.
+ */
+ char *(*bdrv_dirname)(BlockDriverState *bs, Error **errp);
+
/* aio */
BlockAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
@@ -4917,6 +4917,32 @@ void bdrv_refresh_filename(BlockDriverState *bs)
}
}
+char *bdrv_dirname(BlockDriverState *bs, Error **errp)
+{
+ BlockDriver *drv = bs->drv;
+
+ if (!drv) {
+ error_setg(errp, "Node '%s' is ejected", bs->node_name);
+ return NULL;
+ }
+
+ if (drv->bdrv_dirname) {
+ return drv->bdrv_dirname(bs, errp);
+ }
+
+ if (bs->file) {
+ return bdrv_dirname(bs->file->bs, errp);
+ }
+
+ if (bs->exact_filename[0] != '\0') {
+ return path_combine(bs->exact_filename, "");
+ }
+
+ error_setg(errp, "Cannot generate a base directory for %s nodes",
+ drv->format_name);
+ return NULL;
+}
+
/*
* Hot add/remove a BDS's child. So the user can take a child offline when
* it is broken and take a new child online
This function may be implemented by block drivers to derive a directory name from a BDS. Concatenating this g_free()-able string with a relative filename must result in a valid (not necessarily existing) filename, so this is a function that should generally be not implemented by format drivers, because this is protocol-specific. If a BDS's driver does not implement this function, bdrv_dirname() will fall through to the BDS's file if it exists. If it does not, the exact_filename field will be used to generate a directory name. Signed-off-by: Max Reitz <mreitz@redhat.com> --- include/block/block.h | 1 + include/block/block_int.h | 7 +++++++ block.c | 26 ++++++++++++++++++++++++++ 3 files changed, 34 insertions(+)