f2fs: fix lost xattrs of directories

This patch enhances the xattr consistency of dirs from suddern power-cuts.

Possible scenario would be:
1. dir->setxattr used by per-file encryption
2. file->setxattr goes into inline_xattr
3. file->fsync

In that case, we should do checkpoint for #1.
Otherwise we'd lose dir's key information for the file given #2.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/checkpoint.c

@@ -1152,6 +1152,7 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 
 	clear_prefree_segments(sbi, cpc);
 	clear_sbi_flag(sbi, SBI_IS_DIRTY);
+	clear_sbi_flag(sbi, SBI_NEED_CP);
 
 	return 0;
 }

fs/f2fs/f2fs.h

@@ -756,6 +756,7 @@ enum {
 	SBI_NEED_FSCK,				/* need fsck.f2fs to fix */
 	SBI_POR_DOING,				/* recovery is doing or not */
 	SBI_NEED_SB_WRITE,			/* need to recover superblock */
+	SBI_NEED_CP,				/* need to checkpoint */
 };
 
 enum {

fs/f2fs/file.c

@@ -135,6 +135,8 @@ static inline bool need_do_checkpoint(struct inode *inode)
 
 	if (!S_ISREG(inode->i_mode) || inode->i_nlink != 1)
 		need_cp = true;
+	else if (is_sbi_flag_set(sbi, SBI_NEED_CP))
+		need_cp = true;
 	else if (file_enc_name(inode) && need_dentry_mark(sbi, inode->i_ino))
 		need_cp = true;
 	else if (file_wrong_pino(inode))

fs/f2fs/xattr.c

@@ -548,6 +548,8 @@ static int __f2fs_setxattr(struct inode *inode, int index,
 			!strcmp(name, F2FS_XATTR_NAME_ENCRYPTION_CONTEXT))
 		f2fs_set_encrypted_inode(inode);
 	f2fs_mark_inode_dirty_sync(inode);
+	if (!error && S_ISDIR(inode->i_mode))
+		set_sbi_flag(F2FS_I_SB(inode), SBI_NEED_CP);
 exit:
 	kzfree(base_addr);
 	return error;