From: Dave Chinner Subject: Re: [PATCH 04/12 v2] xfs: pass LLONG_MAX to truncate_inode_pages_range Date: Mon, 16 Jul 2012 09:11:17 +1000 Message-ID: <20120715231117.GD30524@devil.redhat.com> References: <1342185555-21146-1-git-send-email-lczerner@redhat.com> <1342185555-21146-4-git-send-email-lczerner@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu, achender@linux.vnet.ibm.com To: Lukas Czerner Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32964 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751115Ab2GOXLb (ORCPT ); Sun, 15 Jul 2012 19:11:31 -0400 Content-Disposition: inline In-Reply-To: <1342185555-21146-4-git-send-email-lczerner@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Jul 13, 2012 at 03:19:07PM +0200, Lukas Czerner wrote: > Currently we're passing -1 to truncate_inode_pages_range() which is > actually really confusing since the argument is signed so we do not get > "huge" number as one would expect, but rather just -1. To make things > clearer and easier for truncate_inode_pages_range() just pass LLONG_MAX > since it is actually what was intended anyway. > > It also makes thing easier for allowing truncate_inode_pages_range() to > handle non page aligned regions. Moreover letting the lend argument to > be negative might actually hide some bugs. > > Signed-off-by: Lukas Czerner > Cc: Dave Chinner > --- > fs/xfs/xfs_fs_subr.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/xfs_fs_subr.c b/fs/xfs/xfs_fs_subr.c > index 652b875..6e9b052 100644 > --- a/fs/xfs/xfs_fs_subr.c > +++ b/fs/xfs/xfs_fs_subr.c > @@ -34,7 +34,8 @@ xfs_tosspages( > { > /* can't toss partial tail pages, so mask them out */ > last &= ~(PAGE_SIZE - 1); > - truncate_inode_pages_range(VFS_I(ip)->i_mapping, first, last - 1); > + truncate_inode_pages_range(VFS_I(ip)->i_mapping, first, > + last == -1 ? LLONG_MAX : last); The last paramter changed from (last -1) to last. so if we pass in last = 16384, we now truncate to 16384 (first byte of page index 5) instead of 16383 (last byte of page index 4). That's a change of behaviour and a potential off-by one error, right? > @@ -53,7 +54,8 @@ xfs_flushinval_pages( > ret = filemap_write_and_wait_range(mapping, first, > last == -1 ? LLONG_MAX : last); > if (!ret) > - truncate_inode_pages_range(mapping, first, last); > + truncate_inode_pages_range(mapping, first, > + last == -1 ? LLONG_MAX : last); Given this is also done immediately above in the function, perhaps this should be done before anything: if (last == -1) last = LLONG_MAX; and the parameter simply passed to the two functions without the conditional logic? Cheers, Dave. -- Dave Chinner dchinner@redhat.com