From: David Howells <dhowells@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org,
viro@zeniv.linux.org.uk, tytso@mit.edu, adilger.kernel@dilger.ca,
darrick.wong@oracle.com, clm@fb.com, josef@toxicpanda.com,
dsterba@suse.com, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: Problems with determining data presence by examining extents?
Date: Wed, 15 Jan 2020 14:15:34 +0000 [thread overview]
Message-ID: <24480.1579097734@warthog.procyon.org.uk> (raw)
In-Reply-To: <20200115083854.GB23039@lst.de>
Christoph Hellwig <hch@lst.de> wrote:
> The whole idea of an out of band interface is going to be racy and suffer
> from implementation loss. I think what you want is something similar to
> the NFSv4.2 READ_PLUS operation - give me that if there is any and
> otherwise tell me that there is a hole. I think this could be a new
> RWF_NOHOLE or similar flag, just how to return the hole size would be
> a little awkward. Maybe return a specific negative error code (ENODATA?)
> and advance the iov anyway.
Just having call_iter_read() return a short read could be made to suffice...
provided the filesystem doesn't return data I haven't written in (which could
cause apparent corruption) and does return data I have written in (otherwise I
have to go back to the server).
David
prev parent reply other threads:[~2020-01-15 14:15 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 16:48 Problems with determining data presence by examining extents? David Howells
2020-01-14 22:49 ` Theodore Y. Ts'o
2020-01-15 13:50 ` David Howells
2020-01-15 3:54 ` Qu Wenruo
2020-01-15 12:46 ` Andreas Dilger
2020-01-15 13:10 ` Qu Wenruo
2020-01-15 13:31 ` Christoph Hellwig
2020-01-15 14:35 ` David Howells
2020-01-15 14:48 ` Christoph Hellwig
2020-01-15 14:59 ` David Howells
2020-01-16 10:13 ` Christoph Hellwig
2020-01-17 16:43 ` David Howells
2020-01-15 19:48 ` Andreas Dilger
2020-01-15 20:55 ` David Howells
2020-01-15 22:11 ` Andreas Dilger
2020-01-15 23:09 ` David Howells
2020-01-26 18:19 ` Zygo Blaxell
2020-01-16 10:16 ` Christoph Hellwig
2020-01-15 14:20 ` David Howells
2020-01-15 14:05 ` David Howells
2020-01-15 14:24 ` Qu Wenruo
2020-01-15 14:50 ` David Howells
2020-01-15 8:38 ` Christoph Hellwig
2020-01-15 14:15 ` David Howells [this message]
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