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From: Christoph Hellwig <hch@infradead.org>
To: P??draig Brady <P@draigBrady.com>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: fallocate vs ENOSPC
Date: Fri, 25 Nov 2011 05:40:50 -0500	[thread overview]
Message-ID: <20111125104050.GA26729@infradead.org> (raw)
In-Reply-To: <4ECF6D41.2040801@draigBrady.com>

On Fri, Nov 25, 2011 at 10:26:09AM +0000, P??draig Brady wrote:
> I was wondering about adding fallocate() to cp,
> where one of the benefits would be immediate indication of ENOSPC.
> I'm now wondering though might fallocate() fail to allocate an
> extent with ENOSPC, but there could be fragmented space available to write()?

fallocate isn't guaranteed to allocate a single or even contiguous
extents, it just allocate the given amount of space, and if the fs isn't
too fragmented and the allocator not braindead it will be sufficiently
contiguous.  Also all Linux implementation may actually still fail a write
later if extreme corner cases when btree splits or other metadata
operations during unwritten extent conversions go over the space limit.


  reply	other threads:[~2011-11-25 10:40 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-25 10:26 fallocate vs ENOSPC Pádraig Brady
2011-11-25 10:40 ` Christoph Hellwig [this message]
2011-11-27  3:14   ` Ted Ts'o
2011-11-27 23:43     ` Dave Chinner
2011-11-28  0:13       ` Pádraig Brady
2011-11-28  3:51         ` Dave Chinner
2011-11-28  0:40       ` Theodore Tso
2011-11-28  5:10         ` Dave Chinner
2011-11-28  8:55           ` Pádraig Brady
2011-11-28 10:41             ` tao.peng
2011-11-28 12:02               ` Pádraig Brady
2011-11-28 14:36             ` Theodore Tso
2011-11-28 14:51               ` Pádraig Brady
2011-11-28 20:29                 ` Ted Ts'o
2011-11-28 20:49                   ` Jeremy Allison
2011-11-29 22:39                     ` Eric Sandeen
2011-11-29 23:04                       ` Jeremy Allison
2011-11-29 23:19                         ` Eric Sandeen
2011-11-28 18:49               ` Jeremy Allison
2011-11-29  0:26                 ` Dave Chinner
2011-11-29  0:45                   ` Jeremy Allison
2011-11-29  0:24             ` Dave Chinner
2011-11-29 14:11               ` Pádraig Brady
2011-11-29 23:37                 ` Dave Chinner
2011-11-30  9:28                   ` Pádraig Brady
2011-11-30 15:32                     ` Ted Ts'o
2011-11-30 16:11                       ` Pádraig Brady
2011-11-30 17:01                         ` Ted Ts'o
2011-11-30 23:39                           ` Dave Chinner
2011-12-01  0:11                           ` Pádraig Brady
2011-12-07 11:42                             ` Pádraig Brady

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