f2fs: convert inline_data when i_size becomes large

If i_size becomes large outside of MAX_INLINE_DATA, we shoud convert the inode.
Otherwise, we can make some dirty pages during the truncation, and those pages
will be written through f2fs_write_data_page.
At that moment, the inode has still inline_data, so that it tries to write non-
zero pages into inline_data area.
Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -522,6 +522,12 @@ void f2fs_truncate(struct inode *inode)
 
 	trace_f2fs_truncate(inode);
 
+	/* we should check inline_data size */
+	if (f2fs_has_inline_data(inode) && !f2fs_may_inline(inode)) {
+		if (f2fs_convert_inline_inode(inode))
+			return;
+	}
+
 	if (!truncate_blocks(inode, i_size_read(inode), true)) {
 		inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 		mark_inode_dirty(inode);

fs/f2fs/inline.c

@@ -24,6 +24,9 @@ bool f2fs_may_inline(struct inode *inode)
 	if (!S_ISREG(inode->i_mode))
 		return false;
 
+	if (i_size_read(inode) > MAX_INLINE_DATA)
+		return false;
+
 	return true;
 }