createiso: Use unique paths for breaking hardlinks

If the data needs to be split into multiple ISOs, we need to make sure
the paths are unique for each image. Otherwise all files will be copied
into the same directory, and once the first image is finished, the whole
staging dir is deleting. That obviously breaks the tasks that are still
in progress.

JIRA: COMPOSE-2610
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>

pungi/paths.py

@@ -287,13 +287,16 @@ class WorkPaths(object):
             makedirs(path)
         return path
 
-    def iso_staging_dir(self, arch, variant, create_dir=True):
+    def iso_staging_dir(self, arch, variant, filename, create_dir=True):
         """
         Examples:
-            work/x86_64/Server/iso-staging-dir
+            work/x86_64/Server/iso-staging-dir/file.iso/
         """
         path = os.path.join(
-            self.topdir(arch, create_dir=create_dir), variant.uid, "iso-staging-dir"
+            self.topdir(arch, create_dir=create_dir),
+            variant.uid,
+            "iso-staging-dir",
+            filename
         )
         if create_dir:
             makedirs(path)

pungi/phases/createiso.py

@@ -208,7 +208,9 @@ class CreateIsoThread(WorkerThread):
                             cmd["bootable"], cmd["disc_num"], cmd["disc_count"])
 
         # Delete staging directory if present.
-        staging_dir = compose.paths.work.iso_staging_dir(arch, variant)
+        staging_dir = compose.paths.work.iso_staging_dir(
+            arch, variant, filename=os.path.basename(cmd["iso_path"])
+        )
         if os.path.exists(staging_dir):
             shutil.rmtree(staging_dir)
 
@@ -451,8 +453,12 @@ def prepare_iso(compose, arch, variant, disc_num=1, disc_count=None, split_iso_d
         data = iso.get_graft_points([iso._paths_from_list(tree_dir, split_iso_data["files"]), iso_dir])
 
     if compose.conf["createiso_break_hardlinks"]:
-        compose.log_debug("Breaking hardlinks for ISO for %s.%s" % (variant, arch))
-        break_hardlinks(data, compose.paths.work.iso_staging_dir(arch, variant))
+        compose.log_debug(
+            "Breaking hardlinks for ISO %s for %s.%s" % (filename, variant, arch)
+        )
+        break_hardlinks(
+            data, compose.paths.work.iso_staging_dir(arch, variant, filename)
+        )
 
     # TODO: /content /graft-points
     gp = "%s-graft-points" % iso_dir