[PATCH v3 06/17] btrfs: add new FEATURE_INCOMPAT_ENCRYPT flag

[Sweet Tea Dorminy <sweettea-kernel@dorminy.me>]

From: Omar Sandoval <osandov@osandov.com>

As encrypted files will be incompatible with older filesystem versions,
new filesystems should be created with an incompat flag for fscrypt,
which will gate access to the encryption ioctls.

Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
 fs/btrfs/fs.h              | 7 ++++---
 fs/btrfs/super.c           | 5 +++++
 fs/btrfs/sysfs.c           | 6 ++++++
 include/uapi/linux/btrfs.h | 1 +
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/fs.h b/fs/btrfs/fs.h
index ef07c6c252d8..15d0dc425e32 100644
--- a/fs/btrfs/fs.h
+++ b/fs/btrfs/fs.h
@@ -223,9 +223,10 @@ enum {
 	 * Features under developmen like Extent tree v2 support is enabled
 	 * only under CONFIG_BTRFS_DEBUG.
 	 */
-#define BTRFS_FEATURE_INCOMPAT_SUPP		\
-	(BTRFS_FEATURE_INCOMPAT_SUPP_STABLE |	\
-	 BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2)
+#define BTRFS_FEATURE_INCOMPAT_SUPP		 \
+	(BTRFS_FEATURE_INCOMPAT_SUPP_STABLE |	 \
+	 BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2 | \
+	 BTRFS_FEATURE_INCOMPAT_ENCRYPT)
 
 #else
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 08b1e2ded5be..0cc9c2909f64 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2421,6 +2421,11 @@ static int __init btrfs_print_mod_info(void)
 			", fsverity=yes"
 #else
 			", fsverity=no"
+#endif
+#ifdef CONFIG_FS_ENCRYPTION
+			", fscrypt=yes"
+#else
+			", fscrypt=no"
 #endif
 			;
 	pr_info("Btrfs loaded%s\n", options);
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index b1d1ac25237b..ac955f920edf 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -301,6 +301,9 @@ BTRFS_FEAT_ATTR_INCOMPAT(extent_tree_v2, EXTENT_TREE_V2);
 #ifdef CONFIG_FS_VERITY
 BTRFS_FEAT_ATTR_COMPAT_RO(verity, VERITY);
 #endif
+#ifdef CONFIG_FS_ENCRYPTION
+BTRFS_FEAT_ATTR_INCOMPAT(encryption, ENCRYPT);
+#endif /* CONFIG_FS_ENCRYPTION */
 
 /*
  * Features which depend on feature bits and may differ between each fs.
@@ -331,6 +334,9 @@ static struct attribute *btrfs_supported_feature_attrs[] = {
 #ifdef CONFIG_FS_VERITY
 	BTRFS_FEAT_ATTR_PTR(verity),
 #endif
+#ifdef CONFIG_FS_ENCRYPTION
+	BTRFS_FEAT_ATTR_PTR(encryption),
+#endif /* CONFIG_FS_ENCRYPTION */
 	NULL
 };
 
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index dbb8b96da50d..98d1fa51a351 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -333,6 +333,7 @@ struct btrfs_ioctl_fs_info_args {
 #define BTRFS_FEATURE_INCOMPAT_RAID1C34		(1ULL << 11)
 #define BTRFS_FEATURE_INCOMPAT_ZONED		(1ULL << 12)
 #define BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2	(1ULL << 13)
+#define BTRFS_FEATURE_INCOMPAT_ENCRYPT		(1ULL << 14)
 
 struct btrfs_ioctl_feature_flags {
 	__u64 compat_flags;
-- 
2.41.0