From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 8/8] xfs: introduce an always_cow mode
Date: Wed, 20 Feb 2019 15:58:25 +0100 [thread overview]
Message-ID: <20190220145825.GA27724@lst.de> (raw)
In-Reply-To: <20190219175358.GH32253@magnolia>
On Tue, Feb 19, 2019 at 09:53:58AM -0800, Darrick J. Wong wrote:
> xfsrestore tries to RESVSP space for its index file and fails,
> presumably because the vfs intercepts the RESVSP ioctl and calls
> vfs_fallocate. But then xfsrestore seems to run ALLOCSP, which afaict
> succeeds... ?
s/ALLOCSP/fallocate/ I think.
But not, fallocate on an always_cow inode does not work, because
it can't (modulo the non-persistent delalloc only idea from Dave).
>
> Two questions:
>
> - Are you going to mask off xfs_ioc_space from alwayscow inodes like you
> did for xfs_file_fallocate?
xfs_ioc_space does a few different things:
- it contains a RESVP implementation that actually is dead code,
as the VFS takes care of it.
- it contains a UNRESVSP implementation, this is supported by
always_cow
- it contains a ZERO_RANGE implementation, also supported by
always_cow
So nothing to do there.
> - What are we going to do for xfsrestore if it encounters a filesystem
> where everything is alwayscow?
>
> > xfs/205
>
> "disk full, expected" ?
>
> /me wonders, since this is an ENOSPC test, why would it fail if we run
> out of space.
As far as I can tell because we run out of space too early due to the
transient double block usage due to the COW writes.
next prev parent reply other threads:[~2019-02-20 14:58 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-18 9:18 COW improvements and always_cow support V5 Christoph Hellwig
2019-02-18 9:18 ` [PATCH 1/8] xfs: make xfs_bmbt_to_iomap more useful Christoph Hellwig
2019-02-18 9:18 ` [PATCH 2/8] xfs: fix SEEK_DATA for speculative COW fork preallocation Christoph Hellwig
2019-02-19 5:13 ` Darrick J. Wong
2019-02-18 9:18 ` [PATCH 3/8] xfs: don't use delalloc extents for COW on files with extsize hints Christoph Hellwig
2019-02-19 5:17 ` Darrick J. Wong
2019-02-21 17:58 ` Brian Foster
2019-02-21 22:56 ` Darrick J. Wong
2019-02-22 14:16 ` Christoph Hellwig
2019-02-18 9:18 ` [PATCH 4/8] xfs: also truncate holes covered by COW blocks Christoph Hellwig
2019-02-18 9:18 ` [PATCH 5/8] xfs: merge COW handling into xfs_file_iomap_begin_delay Christoph Hellwig
2019-02-19 18:12 ` Darrick J. Wong
2019-02-21 17:59 ` Brian Foster
2019-02-21 21:30 ` Darrick J. Wong
2019-02-22 12:31 ` Brian Foster
2019-02-22 14:22 ` Christoph Hellwig
2019-02-22 14:20 ` Christoph Hellwig
2019-02-22 15:20 ` Brian Foster
2019-02-18 9:18 ` [PATCH 6/8] xfs: make COW fork unwritten extent conversions more robust Christoph Hellwig
2019-02-19 18:16 ` Darrick J. Wong
2019-02-18 9:18 ` [PATCH 7/8] xfs: report IOMAP_F_SHARED from xfs_file_iomap_begin_delay Christoph Hellwig
2019-02-19 5:20 ` Darrick J. Wong
2019-02-18 9:18 ` [PATCH 8/8] xfs: introduce an always_cow mode Christoph Hellwig
2019-02-19 5:25 ` Darrick J. Wong
2019-02-19 17:53 ` Darrick J. Wong
2019-02-20 14:58 ` Christoph Hellwig [this message]
2019-02-20 15:00 ` Christoph Hellwig
2019-02-19 18:31 ` Darrick J. Wong
2019-02-20 15:08 ` Christoph Hellwig
2019-02-21 17:31 ` Darrick J. Wong
2019-02-18 9:19 ` xfs/420 and xfs/421: don't disturb unwritten status with md5sum Christoph Hellwig
2019-03-09 10:32 ` Eryu Guan
2019-03-09 17:34 ` Darrick J. Wong
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