[OE-core] [PATCH] classes/image_types_wic.bbclass: fix racing risk on rootfs

[Hongxu Jia]

Since wic image creation will temporarily update rootfs/etc/fstab
(*temporarily* means the fstab will be recovered after wic image creation),
there is still racing risk during the temporarily time for other image
creation (such as tar, ext)

Make a copy of rootfs(as rootfs_wic), and create wic image based on the copy.

Signed-off-by: Hongxu Jia <hongxu.jia at windriver.com>
---
 meta/classes/image_types_wic.bbclass | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/meta/classes/image_types_wic.bbclass b/meta/classes/image_types_wic.bbclass
index f350dc2..2a93143 100644
--- a/meta/classes/image_types_wic.bbclass
+++ b/meta/classes/image_types_wic.bbclass
@@ -26,15 +26,20 @@ def wks_search(files, search_path):
 WIC_CREATE_EXTRA_ARGS ?= ""
 
 IMAGE_CMD_wic () {
+	[ -d "${IMAGE_ROOTFS}_wic" ] && rm -rf "${IMAGE_ROOTFS}_wic"
+	# Refer oe.path.copytree(src, dst): ${WORKDIR}/rootfs -> ${WORKDIR}/rootfs_wic
+	mkdir -p "${IMAGE_ROOTFS}_wic"
+	tar --xattrs --xattrs-include="*" -cf - -S -C "${IMAGE_ROOTFS}" -p . | tar --xattrs --xattrs-include="*" -xf - -C "${IMAGE_ROOTFS}_wic"
+
 	out="${IMGDEPLOYDIR}/${IMAGE_NAME}"
 	wks="${WKS_FULL_PATH}"
 	if [ -z "$wks" ]; then
 		bbfatal "No kickstart files from WKS_FILES were found: ${WKS_FILES}. Please set WKS_FILE or WKS_FILES appropriately."
 	fi
 
-	BUILDDIR="${TOPDIR}" wic create "$wks" --vars "${STAGING_DIR}/${MACHINE}/imgdata/" -e "${IMAGE_BASENAME}" -o "$out/" ${WIC_CREATE_EXTRA_ARGS}
+	BUILDDIR="${TOPDIR}" wic create "$wks" --vars "${STAGING_DIR}/${MACHINE}/imgdata/" -e "${IMAGE_BASENAME}" -r "${IMAGE_ROOTFS}_wic" -o "$out/" ${WIC_CREATE_EXTRA_ARGS}
 	mv "$out/$(basename "${wks%.wks}")"*.direct "$out${IMAGE_NAME_SUFFIX}.wic"
-	rm -rf "$out/"
+	rm -rf "$out/" "${IMAGE_ROOTFS}_wic"
 }
 IMAGE_CMD_wic[vardepsexclude] = "WKS_FULL_PATH WKS_FILES TOPDIR"
 
-- 
2.7.4