rm: fix regression when deleting a file

fix a regression caused by 7dcef0769b1521b8f14bdee58339c26140466c85

Closes: https://bodhi.fedoraproject.org/updates/FEDORA-2019-fff1ded16e#comment-958825

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

.travis.yml

@@ -40,6 +40,7 @@ script:
   - (cd /unionmount-testsuite; sudo unshare -m ./run --ov --fuse=fuse-overlayfs --xdev) || travis_terminate 1;
   - (cd /unionmount-testsuite; sudo FUSE_OVERLAYFS_DISABLE_OVL_WHITEOUT=1 unshare -m ./run --ov --fuse=fuse-overlayfs --xdev) || travis_terminate 1;
   - sudo tests/fedora-installs.sh || travis_terminate 1;
+  - sudo tests/fedora-rm.sh || travis_terminate 1;
   - sudo tests/unlink.sh || travis_terminate 1;
   - (cd $GOPATH/src/github.com/containers/storage/tests; sudo STORAGE_OPTION=overlay.mount_program=/sbin/fuse-overlayfs STORAGE_DRIVER=overlay unshare -m ./test_runner.bash) || travis_terminate 1;
   - (cd $GOPATH/src/github.com/containers/storage/tests; sudo FUSE_OVERLAYFS_DISABLE_OVL_WHITEOUT=1 STORAGE_OPTION=overlay.mount_program=/sbin/fuse-overlayfs STORAGE_DRIVER=overlay unshare -m ./test_runner.bash) || travis_terminate 1;

main.c

@@ -637,11 +637,26 @@ hide_node (struct ovl_data *lo, struct ovl_node *node, bool unlink_src)
         {
           if (node->parent)
             {
-              if (create_whiteout (lo, node->parent, node->name, false, false) < 0)
+              /* If we are here, it means we have no permissions to use mknod.  Also
+                 since the file is not yet moved, creating a whiteout would fail on
+                 the mknodat call.  */
+              if (create_whiteout (lo, node->parent, node->name, true, false) < 0)
                 return -1;
             }
           if (renameat (upper_layer_fd (lo), node->path, lo->workdir_fd, newpath) < 0)
-            return -1;
+            {
+              if (node->parent)
+                {
+                  cleanup_free char *whpath = NULL;
+
+                  ret = asprintf (&whpath, "%s/.wh.%s", node->parent->path, node->name);
+                  /* If the rename failed, then try to delete the whiteout file we
+                     created earlier.  */
+                  if (ret == 0)
+                    unlinkat (upper_layer_fd (lo), whpath, 0);
+                }
+              return -1;
+            }
         }
     }
   else

tests/fedora-installs.sh

@@ -1,10 +1,12 @@
-#!/bin/sh
+#!/bin/bash
+
+set -xeuo pipefail
 
 mkdir lower upper workdir merged
 
 fuse-overlayfs -o lowerdir=lower,upperdir=upper,workdir=workdir,suid,dev merged
 
-docker run --rm -ti -v merged:/merged fedora dnf --installroot /merged --releasever 29 install -y glibc-common gedit
+docker run --rm -ti -v merged:/merged fedora dnf --installroot /merged --releasever 30 install -y glibc-common gedit
 
 umount merged
 
@@ -16,8 +18,11 @@ mkdir upper workdir
 fuse-overlayfs -o lowerdir=lower,upperdir=upper,workdir=workdir,suid,dev merged
 
 # Install some big packages
-docker run --rm -ti -v merged:/merged fedora dnf --installroot /merged --releasever 29 install -y emacs texlive
+docker run --rm -ti -v merged:/merged fedora dnf --installroot /merged --releasever 30 install -y emacs texlive
 
-docker run --rm -ti -v merged:/merged fedora sh -c 'rm /usr/share/glib-2.0/schemas/gschemas.compiled; glib-compile-schemas /usr/share/glib-2.0/schemas/'
+docker run --rm -ti -v merged:/merged fedora sh -c 'rm /merged/usr/share/glib-2.0/schemas/gschemas.compiled; glib-compile-schemas /merged/usr/share/glib-2.0/schemas/'
 
 umount merged
+fuse-overlayfs -o lowerdir=lower,upperdir=upper,workdir=workdir,suid,dev merged
+
+docker run --rm -ti -v merged:/merged fedora sh -c 'rm -rf /merged/usr/share/glib-2.0/'