From: Christoph Hellwig <hch@infradead.org>
To: P??draig Brady <P@draigBrady.com>
Cc: Austin S Hemmelgarn <ahferroin7@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
Andy Lutomirski <luto@amacapital.net>,
Anna Schumaker <Anna.Schumaker@netapp.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-nfs@vger.kernel.org,
Linux btrfs Developers List <linux-btrfs@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>, Zach Brown <zab@zabbo.net>,
Al Viro <viro@zeniv.linux.org.uk>, Chris Mason <clm@fb.com>,
Michael Kerrisk-manpages <mtk.manpages@gmail.com>,
andros@netapp.com
Subject: Re: [PATCH v5 8/9] vfs: Add vfs_copy_file_range() support for pagecache copies
Date: Fri, 16 Oct 2015 05:24:53 -0700 [thread overview]
Message-ID: <20151016122453.GB5889@infradead.org> (raw)
In-Reply-To: <5620E74F.50006@draigBrady.com>
On Fri, Oct 16, 2015 at 01:02:23PM +0100, P??draig Brady wrote:
> Right. reflinking is transparent to the user, though its consequences are not.
> Consequences being the possible extra latency or ENOSPC on CoW.
You can get all these consequences without doing the file system reflink
by using a COW file system, any dedup scheme or thinly provisioned or
COW storage devices.
> Therefore reflinking should be an explicit action/flag IMHO.
This still does not make any sense, as it only prevents one of many
ways a file could do COW operations underneath. If you don't want
ENOSPC use fallocate, or the proposed COPY_FALLOC flag. If you want
care about latency you need to carefull benchmark your setup but in
general falloc / COPY_FALLOC might be a good starting point. But for
99% of the copies a reflink is exactly the right thing to do.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
To: P??draig Brady <P@draigBrady.com>
Cc: Austin S Hemmelgarn
<ahferroin7-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
Anna Schumaker
<Anna.Schumaker-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org>,
"Darrick J. Wong"
<darrick.wong-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Linux btrfs Developers List
<linux-btrfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Linux FS Devel
<linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Linux API <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Zach Brown <zab-ugsP4Wv/S6ZeoWH0uzbU5w@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
Chris Mason <clm-b10kYP2dOMg@public.gmane.org>,
Michael Kerrisk-manpages
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
andros-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH v5 8/9] vfs: Add vfs_copy_file_range() support for pagecache copies
Date: Fri, 16 Oct 2015 05:24:53 -0700 [thread overview]
Message-ID: <20151016122453.GB5889@infradead.org> (raw)
In-Reply-To: <5620E74F.50006-V8g9lnOeT5ydJdNcDFJN0w@public.gmane.org>
On Fri, Oct 16, 2015 at 01:02:23PM +0100, P??draig Brady wrote:
> Right. reflinking is transparent to the user, though its consequences are not.
> Consequences being the possible extra latency or ENOSPC on CoW.
You can get all these consequences without doing the file system reflink
by using a COW file system, any dedup scheme or thinly provisioned or
COW storage devices.
> Therefore reflinking should be an explicit action/flag IMHO.
This still does not make any sense, as it only prevents one of many
ways a file could do COW operations underneath. If you don't want
ENOSPC use fallocate, or the proposed COPY_FALLOC flag. If you want
care about latency you need to carefull benchmark your setup but in
general falloc / COPY_FALLOC might be a good starting point. But for
99% of the copies a reflink is exactly the right thing to do.
next prev parent reply other threads:[~2015-10-16 12:24 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-30 17:26 [PATCH v5 0/9] VFS: In-kernel copy system call Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` [PATCH v5 1/9] vfs: add copy_file_range syscall and vfs helper Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` [PATCH v5 2/9] x86: add sys_copy_file_range to syscall tables Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` [PATCH v5 3/9] btrfs: add .copy_file_range file operation Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` [PATCH v5 4/9] vfs: Copy should check len after file open mode Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-10-11 14:22 ` Christoph Hellwig
2015-10-11 14:22 ` Christoph Hellwig
2015-09-30 17:26 ` [PATCH v5 5/9] vfs: Copy shouldn't forbid ranges inside the same file Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-10-11 14:22 ` Christoph Hellwig
2015-10-14 17:37 ` Anna Schumaker
2015-10-14 17:37 ` Anna Schumaker
2015-10-14 17:37 ` Anna Schumaker
2015-10-14 18:25 ` Christoph Hellwig
2015-10-14 18:27 ` Anna Schumaker
2015-10-14 18:27 ` Anna Schumaker
2015-10-14 18:27 ` Anna Schumaker
2015-09-30 17:26 ` [PATCH v5 6/9] vfs: Copy should use file_out rather than file_in Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-10-11 14:24 ` Christoph Hellwig
2015-09-30 17:26 ` [PATCH v5 7/9] vfs: Remove copy_file_range mountpoint checks Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-10-11 14:23 ` Christoph Hellwig
2015-10-14 17:41 ` Anna Schumaker
2015-10-14 17:41 ` Anna Schumaker
2015-10-14 18:25 ` Christoph Hellwig
2015-10-14 18:25 ` Christoph Hellwig
2015-09-30 17:26 ` [PATCH v5 8/9] vfs: Add vfs_copy_file_range() support for pagecache copies Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-10-08 1:40 ` Neil Brown
2015-10-09 11:15 ` Pádraig Brady
2015-10-09 11:15 ` Pádraig Brady
2015-10-13 20:25 ` Anna Schumaker
2015-10-13 20:25 ` Anna Schumaker
2015-10-14 7:41 ` Christoph Hellwig
2015-10-14 7:41 ` Christoph Hellwig
2015-10-13 19:45 ` Anna Schumaker
2015-10-13 19:45 ` Anna Schumaker
2015-10-13 19:45 ` Anna Schumaker
2015-10-11 14:22 ` Christoph Hellwig
2015-10-11 14:22 ` Christoph Hellwig
2015-10-12 23:17 ` Darrick J. Wong
2015-10-12 23:17 ` Darrick J. Wong
2015-10-13 3:36 ` Trond Myklebust
2015-10-13 7:19 ` Darrick J. Wong
2015-10-13 7:19 ` Darrick J. Wong
2015-10-13 7:30 ` Christoph Hellwig
2015-10-13 7:30 ` Christoph Hellwig
2015-10-13 7:27 ` Christoph Hellwig
2015-10-13 7:27 ` Christoph Hellwig
2015-11-10 6:24 ` Darrick J. Wong
2015-10-14 17:59 ` Anna Schumaker
2015-10-14 17:59 ` Anna Schumaker
2015-10-14 17:59 ` Anna Schumaker
2015-10-14 18:08 ` Andy Lutomirski
2015-10-14 18:27 ` Christoph Hellwig
2015-10-14 18:38 ` Andy Lutomirski
2015-10-14 18:38 ` Andy Lutomirski
2015-10-14 18:49 ` Christoph Hellwig
2015-10-14 18:49 ` Christoph Hellwig
2015-10-14 18:53 ` Andy Lutomirski
2015-10-14 19:14 ` Austin S Hemmelgarn
2015-10-14 19:14 ` Austin S Hemmelgarn
2015-10-14 19:39 ` Pádraig Brady
2015-10-14 19:39 ` Pádraig Brady
2015-10-15 5:56 ` Christoph Hellwig
2015-10-15 5:56 ` Christoph Hellwig
2015-10-14 19:08 ` Austin S Hemmelgarn
2015-10-14 19:08 ` Austin S Hemmelgarn
2015-10-15 6:36 ` Christoph Hellwig
2015-10-15 6:36 ` Christoph Hellwig
2015-10-15 12:24 ` Austin S Hemmelgarn
2015-10-15 12:24 ` Austin S Hemmelgarn
2015-10-16 5:38 ` Christoph Hellwig
2015-10-16 5:38 ` Christoph Hellwig
2015-10-16 11:46 ` Austin S Hemmelgarn
2015-10-16 12:02 ` Pádraig Brady
2015-10-16 12:02 ` Pádraig Brady
2015-10-16 12:24 ` Christoph Hellwig [this message]
2015-10-16 12:24 ` Christoph Hellwig
2015-10-16 12:46 ` Austin S Hemmelgarn
2015-10-16 12:46 ` Austin S Hemmelgarn
2015-10-16 12:21 ` Christoph Hellwig
2015-10-16 12:21 ` Christoph Hellwig
2015-10-16 12:50 ` Austin S Hemmelgarn
2015-10-16 13:12 ` Christoph Hellwig
2015-10-16 14:11 ` Austin S Hemmelgarn
2015-10-14 18:11 ` Darrick J. Wong
2015-10-14 18:11 ` Darrick J. Wong
2015-10-14 18:26 ` Andy Lutomirski
2015-09-30 17:26 ` [PATCH v5 9/9] btrfs: btrfs_copy_file_range() only supports reflinks Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-10-11 14:29 ` Christoph Hellwig
2015-10-11 14:29 ` Christoph Hellwig
2015-10-12 10:23 ` Pádraig Brady
2015-10-12 10:23 ` Pádraig Brady
2015-10-12 14:34 ` Christoph Hellwig
2015-10-12 23:41 ` Darrick J. Wong
2015-10-12 23:41 ` Darrick J. Wong
2015-10-13 7:29 ` Christoph Hellwig
2015-10-13 7:29 ` Christoph Hellwig
2015-10-14 18:46 ` Darrick J. Wong
2015-10-14 18:46 ` Darrick J. Wong
2015-10-15 6:00 ` Christoph Hellwig
2015-10-16 11:49 ` Chris Mason
2015-10-16 11:49 ` Chris Mason
2015-10-16 11:49 ` Chris Mason
2015-10-16 12:25 ` Christoph Hellwig
2015-10-16 12:25 ` Christoph Hellwig
2015-10-16 13:19 ` Chris Mason
2015-10-16 13:19 ` Chris Mason
2015-10-16 13:19 ` Chris Mason
2015-10-16 21:44 ` Dave Chinner
2015-10-17 13:44 ` Chris Mason
2015-10-17 13:44 ` Chris Mason
2015-10-17 13:44 ` Chris Mason
2015-10-15 8:35 ` Dave Chinner
2015-10-15 8:35 ` Dave Chinner
2015-09-30 17:26 ` [PATCH v5 10/9] copy_file_range.2: New page documenting copy_file_range() Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
2015-09-30 17:26 ` Anna Schumaker
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