From: Anton Altaparmakov <aia21@cam.ac.uk>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Milosz Tanski <milosz@adfin.com>,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
Mel Gorman <mgorman@suse.de>,
Volker Lendecke <Volker.Lendecke@sernet.de>,
Tejun Heo <tj@kernel.org>, "Theodore Ts'o" <tytso@mit.edu>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-api@vger.kernel.org,
Michael Kerrisk <mtk.manpages@gmail.com>,
linux-arch@vger.kernel.org, ceph-devel@vger.kernel.org,
fuse-devel@lists.sourceforge.net, linux-nfs@vger.kernel.org,
ocfs2-devel@oss.oracle.com, linux-mm@kvack.org
Subject: Re: [PATCH v5 7/7] add a flag for per-operation O_DSYNC semantics
Date: Fri, 7 Nov 2014 06:22:48 +0200 [thread overview]
Message-ID: <BF30FAEC-D4D3-4079-9ECD-2743747279BD@cam.ac.uk> (raw)
In-Reply-To: <x49r3xf28qn.fsf@segfault.boston.devel.redhat.com>
Hi Jeff,
> On 7 Nov 2014, at 01:46, Jeff Moyer <jmoyer@redhat.com> wrote:
>
> Milosz Tanski <milosz@adfin.com> writes:
>
>> - if (type == READ && (flags & RWF_NONBLOCK))
>> - return -EAGAIN;
>> + if (type == READ) {
>> + if (flags & RWF_NONBLOCK)
>> + return -EAGAIN;
>> + } else {
>> + if (flags & RWF_DSYNC)
>> + return -EINVAL;
>> + }
>
> Minor nit, but I'd rather read something that looks like this:
>
> if (type == READ && (flags & RWF_NONBLOCK))
> return -EAGAIN;
> else if (type == WRITE && (flags & RWF_DSYNC))
> return -EINVAL;
But your version is less logically efficient for the case where "type == READ" is true and "flags & RWF_NONBLOCK" is false because your version then has to do the "if (type == WRITE" check before discovering it does not need to take that branch either, whilst the original version does not have to do such a test at all.
Best regards,
Anton
> I won't lose sleep over it, though.
>
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
University of Cambridge Information Services, Roger Needham Building
7 JJ Thomson Avenue, Cambridge, CB3 0RB, UK
WARNING: multiple messages have this Message-ID (diff)
From: Anton Altaparmakov <aia21-KWPb1pKIrIJaa/9Udqfwiw@public.gmane.org>
To: Jeff Moyer <jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Milosz Tanski <milosz-B5zB6C1i6pkAvxtiuMwx3w@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-aio-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
Mel Gorman <mgorman-l3A5Bk7waGM@public.gmane.org>,
Volker Lendecke
<Volker.Lendecke-3ekOc4rQMZmzQB+pC5nmwQ@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Michael Kerrisk
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
ocfs2-devel-N0ozoZBvEnrZJqsBc5GL+g@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Subject: Re: [PATCH v5 7/7] add a flag for per-operation O_DSYNC semantics
Date: Fri, 7 Nov 2014 06:22:48 +0200 [thread overview]
Message-ID: <BF30FAEC-D4D3-4079-9ECD-2743747279BD@cam.ac.uk> (raw)
In-Reply-To: <x49r3xf28qn.fsf-RRHT56Q3PSP4kTEheFKJxxDDeQx5vsVwAInAS/Ez/D0@public.gmane.org>
Hi Jeff,
> On 7 Nov 2014, at 01:46, Jeff Moyer <jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>
> Milosz Tanski <milosz-B5zB6C1i6pkAvxtiuMwx3w@public.gmane.org> writes:
>
>> - if (type == READ && (flags & RWF_NONBLOCK))
>> - return -EAGAIN;
>> + if (type == READ) {
>> + if (flags & RWF_NONBLOCK)
>> + return -EAGAIN;
>> + } else {
>> + if (flags & RWF_DSYNC)
>> + return -EINVAL;
>> + }
>
> Minor nit, but I'd rather read something that looks like this:
>
> if (type == READ && (flags & RWF_NONBLOCK))
> return -EAGAIN;
> else if (type == WRITE && (flags & RWF_DSYNC))
> return -EINVAL;
But your version is less logically efficient for the case where "type == READ" is true and "flags & RWF_NONBLOCK" is false because your version then has to do the "if (type == WRITE" check before discovering it does not need to take that branch either, whilst the original version does not have to do such a test at all.
Best regards,
Anton
> I won't lose sleep over it, though.
>
> Reviewed-by: Jeff Moyer <jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
University of Cambridge Information Services, Roger Needham Building
7 JJ Thomson Avenue, Cambridge, CB3 0RB, UK
WARNING: multiple messages have this Message-ID (diff)
From: Anton Altaparmakov <aia21@cam.ac.uk>
To: Jeff Moyer <jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Milosz Tanski <milosz-B5zB6C1i6pkAvxtiuMwx3w@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-aio-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
Mel Gorman <mgorman-l3A5Bk7waGM@public.gmane.org>,
Volker Lendecke
<Volker.Lendecke-3ekOc4rQMZmzQB+pC5nmwQ@public.gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Michael Kerrisk
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
ocfs2-devel-N0ozoZBvEnrZJqsBc5GL+g@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org
Subject: [Ocfs2-devel] [PATCH v5 7/7] add a flag for per-operation O_DSYNC semantics
Date: Fri, 7 Nov 2014 06:22:48 +0200 [thread overview]
Message-ID: <BF30FAEC-D4D3-4079-9ECD-2743747279BD@cam.ac.uk> (raw)
In-Reply-To: <x49r3xf28qn.fsf@segfault.boston.devel.redhat.com>
Hi Jeff,
> On 7 Nov 2014, at 01:46, Jeff Moyer <jmoyer@redhat.com> wrote:
>
> Milosz Tanski <milosz@adfin.com> writes:
>
>> - if (type == READ && (flags & RWF_NONBLOCK))
>> - return -EAGAIN;
>> + if (type == READ) {
>> + if (flags & RWF_NONBLOCK)
>> + return -EAGAIN;
>> + } else {
>> + if (flags & RWF_DSYNC)
>> + return -EINVAL;
>> + }
>
> Minor nit, but I'd rather read something that looks like this:
>
> if (type == READ && (flags & RWF_NONBLOCK))
> return -EAGAIN;
> else if (type == WRITE && (flags & RWF_DSYNC))
> return -EINVAL;
But your version is less logically efficient for the case where "type == READ" is true and "flags & RWF_NONBLOCK" is false because your version then has to do the "if (type == WRITE" check before discovering it does not need to take that branch either, whilst the original version does not have to do such a test at all.
Best regards,
Anton
> I won't lose sleep over it, though.
>
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
--
Anton Altaparmakov <aia21@cam.ac.uk> (replace at with @)
University of Cambridge Information Services, Roger Needham Building
7 JJ Thomson Avenue, Cambridge, CB3 0RB, UK
WARNING: multiple messages have this Message-ID (diff)
From: Anton Altaparmakov <aia21@cam.ac.uk>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: Milosz Tanski <milosz@adfin.com>,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
Mel Gorman <mgorman@suse.de>,
Volker Lendecke <Volker.Lendecke@sernet.de>,
Tejun Heo <tj@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-api@vger.kernel.org,
Michael Kerrisk <mtk.manpages@gmail.com>,
linux-arch@vger.kernel.org, ceph-devel@vger.kernel.org,
fuse-devel@lists.sourceforge.net, linux-nfs@vger.kernel.org,
ocfs2-devel@oss.oracle.com, linux-mm@kvack.org
Subject: Re: [PATCH v5 7/7] add a flag for per-operation O_DSYNC semantics
Date: Fri, 7 Nov 2014 06:22:48 +0200 [thread overview]
Message-ID: <BF30FAEC-D4D3-4079-9ECD-2743747279BD@cam.ac.uk> (raw)
In-Reply-To: <x49r3xf28qn.fsf@segfault.boston.devel.redhat.com>
Hi Jeff,
> On 7 Nov 2014, at 01:46, Jeff Moyer <jmoyer@redhat.com> wrote:
>
> Milosz Tanski <milosz@adfin.com> writes:
>
>> - if (type == READ && (flags & RWF_NONBLOCK))
>> - return -EAGAIN;
>> + if (type == READ) {
>> + if (flags & RWF_NONBLOCK)
>> + return -EAGAIN;
>> + } else {
>> + if (flags & RWF_DSYNC)
>> + return -EINVAL;
>> + }
>
> Minor nit, but I'd rather read something that looks like this:
>
> if (type == READ && (flags & RWF_NONBLOCK))
> return -EAGAIN;
> else if (type == WRITE && (flags & RWF_DSYNC))
> return -EINVAL;
But your version is less logically efficient for the case where "type == READ" is true and "flags & RWF_NONBLOCK" is false because your version then has to do the "if (type == WRITE" check before discovering it does not need to take that branch either, whilst the original version does not have to do such a test at all.
Best regards,
Anton
> I won't lose sleep over it, though.
>
> Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
University of Cambridge Information Services, Roger Needham Building
7 JJ Thomson Avenue, Cambridge, CB3 0RB, UK
--
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next prev parent reply other threads:[~2014-11-07 4:23 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-05 21:14 [PATCH v5 0/7] vfs: Non-blockling buffered fs read (page cache only) Milosz Tanski
2014-11-05 21:14 ` [PATCH v5 1/7] vfs: Prepare for adding a new preadv/pwritev with user flags Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-05 21:14 ` [PATCH v5 2/7] vfs: Define new syscalls preadv2,pwritev2 Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-06 23:25 ` Jeff Moyer
2014-11-06 23:25 ` Jeff Moyer
2014-11-07 16:28 ` Milosz Tanski
2014-11-07 16:28 ` Milosz Tanski
2014-11-05 21:14 ` [PATCH v5 3/7] x86: wire up preadv2 and pwritev2 Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-05 21:14 ` [PATCH v5 4/7] vfs: RWF_NONBLOCK flag for preadv2 Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-05 21:14 ` [Ocfs2-devel] " Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-10 16:07 ` Sage Weil
2014-11-10 16:07 ` Sage Weil
2014-11-10 16:07 ` [Ocfs2-devel] " Sage Weil
2014-11-10 16:07 ` Sage Weil
2014-11-05 21:14 ` [PATCH v5 5/7] xfs: add RWF_NONBLOCK support Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-05 21:14 ` [PATCH v5 6/7] fs: pass iocb to generic_write_sync Milosz Tanski
2014-11-05 21:14 ` [Cluster-devel] " Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-06 10:18 ` [Cluster-devel] " Steven Whitehouse
2014-11-06 10:18 ` Steven Whitehouse
2014-11-06 10:18 ` Steven Whitehouse
2014-11-06 10:52 ` [Linux-NTFS-Dev] " Anton Altaparmakov
2014-11-06 10:52 ` [Cluster-devel] " Anton Altaparmakov
2014-11-06 10:52 ` Anton Altaparmakov
2014-11-06 16:14 ` Milosz Tanski
2014-11-06 16:14 ` [Cluster-devel] " Milosz Tanski
2014-11-06 16:14 ` Milosz Tanski
2014-11-06 12:04 ` Jan Kara
2014-11-06 12:04 ` [Cluster-devel] " Jan Kara
2014-11-06 12:04 ` Jan Kara
2014-11-05 21:14 ` [PATCH v5 7/7] fs: add a flag for per-operation O_DSYNC semantics Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-05 21:14 ` [Ocfs2-devel] " Milosz Tanski
2014-11-05 21:14 ` Milosz Tanski
2014-11-06 23:46 ` Jeff Moyer
2014-11-06 23:46 ` [Ocfs2-devel] " Jeff Moyer
2014-11-06 23:46 ` Jeff Moyer
2014-11-07 4:22 ` Anton Altaparmakov [this message]
2014-11-07 4:22 ` [PATCH v5 7/7] " Anton Altaparmakov
2014-11-07 4:22 ` [Ocfs2-devel] " Anton Altaparmakov
2014-11-07 4:22 ` Anton Altaparmakov
2014-11-07 5:52 ` [fuse-devel] " Anand Avati
2014-11-07 5:52 ` [Ocfs2-devel] " Anand Avati
2014-11-07 6:43 ` Anton Altaparmakov
2014-11-07 6:43 ` Anton Altaparmakov
2014-11-07 6:43 ` [Ocfs2-devel] " Anton Altaparmakov
2014-11-07 14:21 ` Roger Willcocks
2014-11-07 14:21 ` Roger Willcocks
2014-11-07 14:21 ` [Ocfs2-devel] " Roger Willcocks
2014-11-07 14:21 ` Roger Willcocks
2014-11-07 14:21 ` Roger Willcocks
2014-11-07 19:58 ` Milosz Tanski
2014-11-07 19:58 ` [Ocfs2-devel] " Milosz Tanski
2014-11-07 19:58 ` Milosz Tanski
2014-11-10 16:07 ` [PATCH v5 7/7] fs: " Sage Weil
2014-11-10 16:07 ` [Ocfs2-devel] " Sage Weil
2014-11-10 16:07 ` Sage Weil
2014-11-06 7:56 ` [PATCH v5 0/7] vfs: Non-blockling buffered fs read (page cache only) Christoph Hellwig
2014-11-06 7:56 ` Christoph Hellwig
2014-11-06 15:46 ` Milosz Tanski
2014-11-06 15:46 ` Milosz Tanski
2014-11-06 15:44 ` [PATCH v2 1/2] Add preadv2/pwritev2 documentation Milosz Tanski
2014-11-06 15:44 ` Milosz Tanski
2014-11-06 15:44 ` [PATCH v2 2/2] RWF_ODSYNC flag for pwritev2 Milosz Tanski
2014-11-06 15:44 ` Milosz Tanski
2014-11-06 16:16 ` [PATCH v5 0/7] vfs: Non-blockling buffered fs read (page cache only) Milosz Tanski
2014-11-06 16:16 ` Milosz Tanski
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