commit, payload-reflink: do not write to the parent repo

reintroduce the feature that was reverted with commit:

28c7bc6d0e

Differently than the original implementation, now we don't attempt any
test for reflinks support on the parent repository, since the test
requires write access to the repository.

Additionally, also check that the two repositories are on the same
device before attempting any reflink.

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

Closes: #1525
Approved by: cgwalters

tests/installed/nondestructive/itest-payload-link.sh

@@ -30,6 +30,9 @@ date
 # Use /var/tmp so we have O_TMPFILE etc.
 prepare_tmpdir /var/tmp
 trap _tmpdir_cleanup EXIT
+# We use this user down below, it needs access too
+setfacl -d -m u:bin:rwX .
+setfacl -m u:bin:rwX .
 ostree --repo=repo init --mode=archive
 echo -e '[archive]\nzlib-level=1\n' >> repo/config
 
@@ -49,23 +52,40 @@ origin=$(cat ${test_tmpdir}/httpd-address)
 
 cleanup() {
     cd ${test_tmpdir}
-    umount mnt || true
-    test -n "${blkdev:-}" && losetup -d ${blkdev} || true
+    for mnt in ${mnts:-}; do
+        umount ${mnt} || true
+    done
+    for blkdev in ${blkdevs:-}; do
+        losetup -d ${blkdev} || true
+    done
 }
 trap cleanup EXIT
 
-mkdir mnt
-truncate -s 2G testblk.img
-if ! blkdev=$(losetup --find --show $(pwd)/testblk.img); then
-    echo "ok # SKIP not run when cannot setup loop device"
-    exit 0
-fi
-
+truncate -s 2G testblk1.img
+blkdev1=$(losetup --find --show $(pwd)/testblk1.img)
+blkdevs="${blkdev1}"
 # This filesystem must support reflinks
-mkfs.xfs -m reflink=1 ${blkdev}
+mkfs.xfs -m reflink=1 ${blkdev1}
+mkdir mnt1
+mount ${blkdev1} mnt1
+mnts=mnt1
 
-mount ${blkdev} mnt
-cd mnt
+truncate -s 2G testblk2.img
+blkdev2=$(losetup --find --show $(pwd)/testblk2.img)
+blkdevs="${blkdev1} ${blkdev2}"
+mkfs.xfs -m reflink=1 ${blkdev2}
+mkdir mnt2
+mount ${blkdev2} mnt2
+mnts="mnt1 mnt2"
+
+cd mnt1
+# See above for setfacl rationale
+setfacl -d -m u:bin:rwX .
+setfacl -m u:bin:rwX .
+ls -al .
+runuser -u bin mkdir foo
+runuser -u bin touch foo/bar
+ls -al foo
 
 # Test that reflink is really there (not just --reflink=auto)
 touch a
@@ -78,13 +98,44 @@ ostree --repo=repo pull --disable-static-deltas origin dupobjects
 find repo -type l -name '*.payload-link' >payload-links.txt
 assert_streq "$(wc -l < payload-links.txt)" "1"
 
-# Disable logging for inner loop
-set +x
 cat payload-links.txt | while read i; do
     payload_checksum=$(basename $(dirname $i))$(basename $i .payload-link)
     payload_checksum_calculated=$(sha256sum $(readlink -f $i) | cut -d ' ' -f 1)
     assert_streq "${payload_checksum}" "${payload_checksum_calculated}"
 done
-set -x
-echo "ok pull creates .payload-link"
+echo "ok payload link"
+
+ostree --repo=repo checkout dupobjects content
+# And another object which differs just in metadata
+cp --reflink=auto content/bigobject{,3}
+chown operator:0 content/bigobject3
+cat >unpriv-child-repo.sh <<EOF
+#!/bin/bash
+# Check that commit to an user repo that has a parent still works
+set -xeuo pipefail
+ostree --repo=child-repo init --mode=bare-user
+ostree --repo=child-repo remote add origin --set=gpg-verify=false ${origin}
+ostree --repo=child-repo config set core.parent $(pwd)/repo
+ostree --repo=child-repo commit -b test content
+EOF
+chmod a+x unpriv-child-repo.sh
+runuser -u bin ./unpriv-child-repo.sh
+find child-repo -type l -name '*.payload-link' >payload-links.txt
+assert_streq "$(wc -l < payload-links.txt)" "0"
+rm content -rf
+
+echo "ok reflink unprivileged with parent repo"
+
+# We can't reflink across devices though
+cd ../mnt2
+ostree --repo=repo init --mode=archive
+ostree --repo=repo config set core.parent $(cd ../mnt1/repo && pwd)
+ostree --repo=../mnt1/repo checkout dupobjects content
+ostree --repo=repo commit -b dupobjects2 --consume --tree=dir=content
+ostree --repo=repo pull --disable-static-deltas origin dupobjects
+find repo -type l -name '*.payload-link' >payload-links.txt
+assert_streq "$(wc -l < payload-links.txt)" "0"
+
+echo "ok payload link across devices"
+
 date