ext4: add shutdown bit and check for it

Add a shutdown bit that will cause ext4 processing to fail immediately
with EIO.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/inline.c

@@ -215,6 +215,9 @@ static void ext4_write_inline_data(struct inode *inode, struct ext4_iloc *iloc,
 	struct ext4_inode *raw_inode;
 	int cp_len = 0;
 
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+		return;
+
 	BUG_ON(!EXT4_I(inode)->i_inline_off);
 	BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);