From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
Christoph Hellwig <hch@lst.de>,
linux-xfs@vger.kernel.org
Subject: Re: [PATCH 5/5] xfs: introduce an always_cow mode
Date: Fri, 21 Sep 2018 07:23:14 +0200 [thread overview]
Message-ID: <20180921052314.GA12825@lst.de> (raw)
In-Reply-To: <20180920212357.GN27618@dastard>
On Fri, Sep 21, 2018 at 07:23:57AM +1000, Dave Chinner wrote:
> sys/fs/xfs/debug/always_cow is the place for this if it is truly a
> global debug option. However, that's probably not the best way to
> enable this sort of debug for people with XFS root filesystems
> trying to test XFS filesystems. I suspect it should be a per-mount
> configuration (i.e. /sys/fs/xfs/<dev>/debug/always_cow)
True.
> However, this mode of operation seems like it is going to form the
> basis of other per-filesystem features, so it would be good to know
> how/if those features make use of this always_cow mode or are
> controlled by some other set of knobs first.
The current atomic write support is a per-inode fcntl based flag.
(used to be an O_ATOMIC per open file flag, but that had all kinds
of issues).
The zoned device support doesn't really existing for a bit of prototype
write path code, but the current assumption is that all files in
ѕequential write only zones have the RT bit set, and will get this
behavior on that an a per-subperblock flag.
In other words - the know here is supposed to remain a debug build
only debug nob.
prev parent reply other threads:[~2018-09-21 11:10 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 14:42 more reflink fixes & debug Christoph Hellwig
2018-09-20 14:42 ` [PATCH 1/5] xfs: cancel COW blocks before swapext Christoph Hellwig
2018-09-20 20:04 ` Darrick J. Wong
2018-09-27 15:07 ` Brian Foster
2018-09-30 22:50 ` Christoph Hellwig
2018-10-01 11:03 ` Brian Foster
2018-09-20 14:42 ` [PATCH 2/5] xfs: skip delalloc COW blocks in xfs_reflink_end_cow Christoph Hellwig
2018-09-20 20:22 ` Darrick J. Wong
2018-09-20 14:42 ` [PATCH 3/5] xfs: fix fork selection in xfs_find_trim_cow_extent Christoph Hellwig
2018-09-20 14:42 ` [PATCH 4/5] xfs: print dangling delalloc extents Christoph Hellwig
2018-09-20 20:06 ` Darrick J. Wong
2018-09-27 15:07 ` Brian Foster
2018-09-20 14:42 ` [PATCH 5/5] xfs: introduce an always_cow mode Christoph Hellwig
2018-09-20 20:17 ` Darrick J. Wong
2018-09-20 21:23 ` Dave Chinner
2018-09-21 5:23 ` Christoph Hellwig [this message]
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