[Buildroot] [PATCH v6 2/2] fs/ext2: Add BR2_TARGET_ROOTFS_EXT2_MKFS_OPTIONS option

[Samuel Martin <s.martin49@gmail.com>]

From: S?bastien Szymanski <sebastien.szymanski@armadeus.com>

This option lets the user specify mke2fs options and/or ext2/3/4
features.

Signed-off-by: S?bastien Szymanski <sebastien.szymanski@armadeus.com>
Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>

---
changes v5->v6:
- wrap help text at 70 chars. (Arnout)
- reword default value explainations (Arnout)

changes v4->v5:
- turn the options to accept any mke2fs options, not only ext2/3/4
  features (Arnout)
- add explaination for the default value for this new option (Arnout)

changes v3->v4:
- none

changes v2->v3:
- none

changes v1->v2:
- rebase
---
 fs/ext2/Config.in | 18 ++++++++++++++++++
 fs/ext2/ext2.mk   |  5 ++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/ext2/Config.in b/fs/ext2/Config.in
index aeee91748..5aec21078 100644
--- a/fs/ext2/Config.in
+++ b/fs/ext2/Config.in
@@ -67,6 +67,24 @@ config BR2_TARGET_ROOTFS_EXT2_RESBLKS
 	  Traditionally, this has been 5%, and all ext-related tools still
 	  default to reserving 5% when creating a new ext filesystem.
 
+config BR2_TARGET_ROOTFS_EXT2_MKFS_OPTIONS
+	string "additional mke2fs options"
+	default "-O ^64bit"
+	help
+	  Specify a space-separated list of mke2fs options, including any
+	  ext2/3/4 filesystem features.
+
+	  For more information about the mke2fs option, see the manual
+	  page mke2fs(8).
+
+	  For more information about the ext2/3/4 features which can be
+	  set, see then manual page ext4(5).
+
+	  The default is "-O ^64bit", i.e. disable the 64-bit filesystem.
+	  This is chosen because U-Boot versions before 2017.02 don't
+	  support that filesystem option, which may render the system
+	  unbootable if it is used.
+
 choice
 	prompt "Compression method"
 	default BR2_TARGET_ROOTFS_EXT2_NONE
diff --git a/fs/ext2/ext2.mk b/fs/ext2/ext2.mk
index b609d36ae..06970f0ee 100644
--- a/fs/ext2/ext2.mk
+++ b/fs/ext2/ext2.mk
@@ -9,6 +9,8 @@ ifeq ($(BR2_TARGET_ROOTFS_EXT2)-$(EXT2_SIZE),y-)
 $(error BR2_TARGET_ROOTFS_EXT2_SIZE cannot be empty)
 endif
 
+EXT2_MKFS_OPTS = $(call qstrip,$(BR2_TARGET_ROOTFS_EXT2_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.
 EXT2_LABEL := $(subst ",,$(BR2_TARGET_ROOTFS_EXT2_LABEL))
@@ -19,7 +21,8 @@ EXT2_OPTS = \
 	-r $(BR2_TARGET_ROOTFS_EXT2_REV) \
 	-N $(BR2_TARGET_ROOTFS_EXT2_INODES) \
 	-m $(BR2_TARGET_ROOTFS_EXT2_RESBLKS) \
-	-L "$(EXT2_LABEL)"
+	-L "$(EXT2_LABEL)" \
+	$(EXT2_MKFS_OPTS)
 
 ROOTFS_EXT2_DEPENDENCIES = host-e2fsprogs
 
-- 
2.13.0