fs/xfs: add support for generating a xfs image

mkfs.xfs is able to populate a filesystem from a directory since
upstream commit [1], included since v6.17.

With this option, it is now possible to create XFS rootfs in
Buildroot. This commit adds this new feature.

[1] https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git/commit/?id=8a4ea72724930cfe262ccda03028264e1a81b145

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Romain Naour <romain.naour@smile.fr>

fs/Config.in

@@ -15,6 +15,7 @@ source "fs/squashfs/Config.in"
 source "fs/tar/Config.in"
 source "fs/ubi/Config.in"
 source "fs/ubifs/Config.in"
+source "fs/xfs/Config.in"
 source "fs/yaffs2/Config.in"
 
 endmenu

fs/xfs/Config.in

@@ -0,0 +1,34 @@
+config BR2_TARGET_ROOTFS_XFS
+	bool "xfs root filesystem"
+	select BR2_PACKAGE_HOST_XFSPROGS
+	help
+	  Build a xfs root filesystem. If you enable this option, you
+	  probably want to enable the xfsprogs package too.
+
+if BR2_TARGET_ROOTFS_XFS
+
+config BR2_TARGET_ROOTFS_XFS_LABEL
+	string "filesystem label"
+	default "rootfs"
+
+config BR2_TARGET_ROOTFS_XFS_SIZE
+	string "exact size"
+	default "300M"
+	help
+	  The size of the filesystem image. This size is passed to the
+	  "truncate -s", so this option recognizes unit suffixes such
+	  as K,M,G (see the manual page truncate(1)). Note the XFS
+	  minimal filesystem size is 300M.
+
+config BR2_TARGET_ROOTFS_XFS_MKFS_OPTIONS
+	string "additional mkfs.xfs options"
+	help
+	  Specify a space-separated list of mkfs.xfs options.
+
+	  For more information about the mke2fs options, see the
+	  manual page mkfs.xfs(8).
+
+	  For more information about the XFS features which can be
+	  set, see also the manual page xfs(5).
+
+endif # BR2_TARGET_ROOTFS_XFS

fs/xfs/xfs.mk

@@ -0,0 +1,33 @@
+################################################################################
+#
+# Build the xfs root filesystem image
+#
+################################################################################
+
+ROOTFS_XFS_SIZE = $(call qstrip,$(BR2_TARGET_ROOTFS_XFS_SIZE))
+ifeq ($(BR2_TARGET_ROOTFS_XFS)-$(ROOTFS_XFS_SIZE),y-)
+$(error BR2_TARGET_ROOTFS_XFS_SIZE cannot be empty)
+endif
+
+ROOTFS_XFS_MKFS_OPTS = $(call qstrip,$(BR2_TARGET_ROOTFS_XFS_MKFS_OPTIONS))
+
+# qstrip results in stripping consecutive spaces into a single one. So the
+# variable is not qstrip-ed to preserve the integrity of the string value.
+ROOTFS_XFS_LABEL = $(subst ",,$(BR2_TARGET_ROOTFS_XFS_LABEL))
+#" comment to balance quotes/parenthesis for syntax highlighting)
+
+ROOTFS_XFS_OPTS = \
+	-f \
+	-p '$(TARGET_DIR)' \
+	-L '$(ROOTFS_XFS_LABEL)' \
+	$(ROOTFS_XFS_MKFS_OPTS)
+
+ROOTFS_XFS_DEPENDENCIES = host-xfsprogs
+
+define ROOTFS_XFS_CMD
+	$(RM) -f $@
+	truncate -s $(ROOTFS_XFS_SIZE) $@
+	$(HOST_DIR)/sbin/mkfs.xfs $(ROOTFS_XFS_OPTS) $@
+endef
+
+$(eval $(rootfs))