f2fs crypto: activate encryption support for fs APIs

This patch activates the following APIs for encryption support.

The rules quoted by ext4 are:
 - An unencrypted directory may contain encrypted or unencrypted files
   or directories.
 - All files or directories in a directory must be protected using the
   same key as their containing directory.
 - Encrypted inode for regular file should not have inline_data.
 - Encrypted symlink and directory may have inline_data and inline_dentry.

This patch activates the following APIs.
1. f2fs_link              : validate context
2. f2fs_lookup            :      ''
3. f2fs_rename            :      ''
4. f2fs_create/f2fs_mkdir : inherit its dir's context
5. f2fs_direct_IO         : do buffered io for regular files
6. f2fs_open              : check encryption info
7. f2fs_file_mmap         :      ''
8. f2fs_setattr           :      ''
9. f2fs_file_write_iter   :      ''           (Called by sys_io_submit)
10. f2fs_fallocate        : do not support fcollapse
11. f2fs_evict_inode      : free_encryption_info

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 98ce1ddf7186..1bf75f8c40bf 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1975,6 +1975,17 @@ static inline int f2fs_sb_has_crypto(struct super_block *sb)
 #endif
 }
 
+static inline bool f2fs_may_encrypt(struct inode *inode)
+{
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+	mode_t mode = inode->i_mode;
+
+	return (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode));
+#else
+	return 0;
+#endif
+}
+
 /* crypto_policy.c */
 int f2fs_is_child_context_consistent_with_parent(struct inode *,
 							struct inode *);