fs: move inode_dio_wait calls into ->setattr

Let filesystems handle waiting for direct I/O requests themselves instead
of doing it beforehand.  This means filesystem-specific locks to prevent
new dio referenes from appearing can be held.  This is important to allow
generalizing i_dio_count to non-DIO_LOCKING filesystems.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/attr.c

@@ -232,9 +232,6 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
 	if (error)
 		return error;
 
-	if (ia_valid & ATTR_SIZE)
-		inode_dio_wait(inode);
-
 	if (inode->i_op->setattr)
 		error = inode->i_op->setattr(dentry, attr);
 	else