From: Ulrich Drepper Subject: Re: [RFC] Heads up on sys_fallocate() Date: Mon, 05 Mar 2007 07:09:38 -0800 Message-ID: <45EC32B2.1000802@redhat.com> References: <20070117094658.GA17390@amitarora.in.ibm.com> <1172789056.11165.42.camel@kleikamp.austin.ibm.com> <20070301233819.GB31072@infradead.org> <200703032345.33137.arnd@arndb.de> <0DA8B217-DDD4-4E05-B000-DEBE3BE55B94@cam.ac.uk> <45EB4A55.3060908@redhat.com> <20070305001621.GB18691@lazybastard.org> <20070305114945.GB454@lazybastard.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig3DED4E7BCB80D8342A0D9A86" Cc: Arnd Bergmann , Christoph Hellwig , Dave Kleikamp , Andrew Morton , "Amit K. Arora" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, suparna@in.ibm.com, cmm@us.ibm.com, alex@clusterfs.com, suzuki@in.ibm.com To: =?UTF-8?B?SsO2cm4gRW5nZWw=?= Return-path: In-Reply-To: <20070305114945.GB454@lazybastard.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig3DED4E7BCB80D8342A0D9A86 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable J=C3=B6rn Engel wrote: > The bad news for posix_fallocate() is that even if libc is smart enough= > to write random data, mmap() can still cause problems. This is not smart, quite to the contrary. The standard guarantees that all not-yet-written-to places in the file are zero. And if a block has already been written posix_fallocate cannot change it. --=20 =E2=9E=A7 Ulrich Drepper =E2=9E=A7 Red Hat, Inc. =E2=9E=A7 444 Castro St = =E2=9E=A7 Mountain View, CA =E2=9D=96 --------------enig3DED4E7BCB80D8342A0D9A86 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFF7DKy2ijCOnn/RHQRAmODAKCG1Y6pSR7he9Nl3SMAN7RzQHoR1gCgmfRd W3+WDlKW/x/J6f7fHH4KvMw= =Jj6G -----END PGP SIGNATURE----- --------------enig3DED4E7BCB80D8342A0D9A86--