[PATCH] deb-dl-dir: Fallback to copying when import-export

[Uladzimir Bely <ubely@ilbers.de>]

By default, hardlinks are used when doing DL_DIR import and export.
This fails if DL_DIR's filesystem differs from TMPDIR's one.

Fallback to file copying (with lower performance and huge disk usage)
in this case.

Signed-off-by: Uladzimir Bely <ubely@ilbers.de>
---
 meta/classes/deb-dl-dir.bbclass | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/meta/classes/deb-dl-dir.bbclass b/meta/classes/deb-dl-dir.bbclass
index 7db25251..d572e6fb 100644
--- a/meta/classes/deb-dl-dir.bbclass
+++ b/meta/classes/deb-dl-dir.bbclass
@@ -80,13 +80,20 @@ deb_dl_dir_import() {
     export pc="${DEBDIR}/${2}"
     export rootfs="${1}"
     sudo mkdir -p "${rootfs}"/var/cache/apt/archives/
+
+    # Use hardlinks with fallback to `cp` if different filesystems
+    export cmd="ln -Pf -t"
+    if [ "$(stat -c %m ${pc})" != "$(stat -c %m ${rootfs})" ]; then
+        export cmd="cp -n --no-preserve=owner"
+    fi
+
     [ ! -d "${pc}" ] && return 0
     flock -s "${pc}".lock -c '
         set -e
         printenv | grep -q BB_VERBOSE_LOGS && set -x
 
         sudo find "${pc}" -type f -iname "*\.deb" -exec \
-            ln -Pf -t "${rootfs}"/var/cache/apt/archives/ {} +
+            ${cmd} "${rootfs}"/var/cache/apt/archives/ {} +
     '
 }
 
@@ -94,6 +101,13 @@ deb_dl_dir_export() {
     export pc="${DEBDIR}/${2}"
     export rootfs="${1}"
     mkdir -p "${pc}"
+
+    # Use hardlinks with fallback to `cp` if different filesystems
+    export cmd="ln -Pf"
+    if [ "$(stat -c %m ${pc})" != "$(stat -c %m ${rootfs})" ]; then
+        export cmd="cp -n"
+    fi
+
     flock "${pc}".lock -c '
         set -e
         printenv | grep -q BB_VERBOSE_LOGS && set -x
@@ -109,7 +123,7 @@ deb_dl_dir_export() {
             if [ -n "$package" ]; then
                 cmp --silent "$package" "$p" && continue
             fi
-            sudo ln -Pf "${p}" "${pc}"
+            sudo ${cmd} "${p}" "${pc}"
         done
         sudo chown -R $(id -u):$(id -g) "${pc}"
     '
-- 
2.20.1