From: hch <hch@lst.de>
To: Hans Holmberg <Hans.Holmberg@wdc.com>
Cc: hch <hch@lst.de>, Florian Weimer <fweimer@redhat.com>,
"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
Carlos Maiolino <cem@kernel.org>,
Dave Chinner <david@fromorbit.com>,
"Darrick J . Wong" <djwong@kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [RFC] xfs: fake fallocate success for always CoW inodes
Date: Tue, 11 Nov 2025 10:05:47 +0100 [thread overview]
Message-ID: <20251111090547.GC11723@lst.de> (raw)
In-Reply-To: <8b9e31f4-0ec6-4817-8214-4dfc4e988265@wdc.com>
On Tue, Nov 11, 2025 at 08:31:30AM +0000, Hans Holmberg wrote:
> In stead of returning success in fallocate(2), could we in stead return
> an distinct error code that would tell the caller that:
>
> The optimized allocation not supported, AND there is no use trying to
> preallocate data using writes?
>
> EUSELESS would be nice to have, but that is not available.
>
> Then posix_fallocate could fail with -EINVAL (which looks legit according
> to the man page "the underlying filesystem does not support the operation")
> or skip the writes and return success (whatever is preferable)
The problem is that both the existing direct callers of fallocate(2)
including all currently released glibc versions do not expect that
return value.
next prev parent reply other threads:[~2025-11-11 9:05 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-06 13:35 [RFC] xfs: fake fallocate success for always CoW inodes Hans Holmberg
2025-11-06 13:48 ` Florian Weimer
2025-11-06 13:52 ` Christoph Hellwig
2025-11-06 14:42 ` Matthew Wilcox
2025-11-06 14:46 ` Christoph Hellwig
2025-11-11 8:31 ` Hans Holmberg
2025-11-11 9:05 ` hch [this message]
2025-11-11 9:50 ` Florian Weimer
2025-11-11 13:40 ` hch
2025-11-06 16:31 ` Florian Weimer
2025-11-06 17:05 ` Christoph Hellwig
2025-11-08 12:30 ` Florian Weimer
2025-11-09 22:15 ` Dave Chinner
2025-11-10 5:27 ` Florian Weimer
2025-11-10 9:38 ` Christoph Hellwig
2025-11-10 10:03 ` Florian Weimer
2025-11-10 20:28 ` Dave Chinner
2025-11-11 8:56 ` Christoph Hellwig
2025-11-10 9:37 ` Christoph Hellwig
2025-11-10 9:44 ` Florian Weimer
2025-11-10 21:33 ` Dave Chinner
2025-11-11 9:04 ` Christoph Hellwig
2025-11-11 9:30 ` Florian Weimer
2025-11-10 9:31 ` Christoph Hellwig
2025-11-10 9:48 ` truncatat? was, " Christoph Hellwig
2025-11-10 10:00 ` Florian Weimer
2025-11-10 9:49 ` Florian Weimer
2025-11-10 9:52 ` Christoph Hellwig
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