f2fs: cover cp_file information with ilock

If a file is linked with other files, it should be checkpointed at every fsync
calls.
For this, we use set_cp_file() with FADVISE_CP_BIT, but previously we didn't
cover the flag by the global lock.
This patch fixes that the inode page stores this correctly.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/dir.c

@@ -346,8 +346,14 @@ static struct page *init_inode_metadata(struct inode *inode,
 
 	init_dent_inode(name, page);
 
-	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
+	/*
+	 * This file should be checkpointed during fsync.
+	 * We lost i_pino from now on.
+	 */
+	if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
+		set_cp_file(inode);
 		inc_nlink(inode);
+	}
 	return page;
 
 error:

fs/f2fs/namei.c

@@ -181,12 +181,6 @@ static int f2fs_link(struct dentry *old_dentry, struct inode *dir,
 	if (err)
 		goto out;
 
-	/*
-	 * This file should be checkpointed during fsync.
-	 * We lost i_pino from now on.
-	 */
-	set_cp_file(inode);
-
 	d_instantiate(dentry, inode);
 	return 0;
 out: