From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: [patch] ext4: clean up the flags passed to __blockdev_direct_IO for extent-based files Date: Fri, 24 Feb 2012 15:52:53 -0600 Message-ID: <4F4806B5.1040908@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org To: Jeff Moyer Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1025 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758152Ab2BXVw4 (ORCPT ); Fri, 24 Feb 2012 16:52:56 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q1OLqt15023107 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 24 Feb 2012 16:52:55 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 2/24/12 3:49 PM, Jeff Moyer wrote: > Hi, > > For extent-based files, you can perform DIO to holes, as mentioned in > the comments in ext4_ext_direct_IO. However, that function passes > DIO_SKIP_HOLES to __blockdev_direct_IO, which is *really* confusing to > the uninitiated reader. The key, here, is that the get_block function > passed in, ext4_get_block_write, completely ignores the create flag that > is passed to it (the create flag is passed in from the direct I/O code, > which uses the DIO_SKIP_HOLES flag to determine whether or not it should > be cleared). > > This is a long-winded way of saying that the DIO_SKIP_HOLES flag is > ultimately ignored. So, in the interest of preserving sanity, I propose > the following patch. > > Cheers, > Jeff > > Signed-off-by: Jeff Moyer Thank you sir. Reviewed-by: Eric Sandeen > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index feaa82f..521ca03 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -2940,7 +2940,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, > ext4_get_block_write, > ext4_end_io_dio, > NULL, > - DIO_LOCKING | DIO_SKIP_HOLES); > + DIO_LOCKING); > if (iocb->private) > EXT4_I(inode)->cur_aio_dio = NULL; > /* > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html