X-Recipient: archive-cygwin AT delorie DOT com X-SWARE-Spam-Status: No, hits=-6.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Message-ID: <4D2783A3.5000008@redhat.com> Date: Fri, 07 Jan 2011 14:20:35 -0700 From: Eric Blake User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Mnenhy/0.8.3 Thunderbird/3.1.7 MIME-Version: 1.0 To: cygwin AT cygwin DOT com Subject: Re: Strange fstatat / stat behavour on directories causing tar "file changed as we read it" error References: <3501944D149644D394474781054F5E98 AT multiplay DOT co DOT uk> In-Reply-To: <3501944D149644D394474781054F5E98@multiplay.co.uk> OpenPGP: url=http://people.redhat.com/eblake/eblake.gpg Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enig5CF67219E832FC4C37D53547" X-IsSubscribed: yes Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com --------------enig5CF67219E832FC4C37D53547 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 01/07/2011 11:21 AM, Steven Hartland wrote: > It turns out that the value of st_size returned by a call > to fstatat on a directory can change even though there > have been no changes at all to said directory or its > children. What file system is this on? Someone else reported the same behavior for "Samba share on QNX through Virtual PC." - if the problem is limited to just a subset of (known-buggy) file systems, it would be nicer to limit the workaround to just those file systems (and have st_size always return 0 for directories from those systems). > The attached patch fixes this strange behaviour by ignoring > size changes for directories as well as correcting the file > size check to also detect file shrinks as well as growths, > which seemed very odd. Thanks for the patch - we'll see if I can get enough free time to apply it and ship a patched tar, or whether cygwin 1.7.8 with a better workaround for the issue gets released first (since there was already talk of getting 1.7.8 complete sometime this month). >=20 > Is there some "meta data" caching going on in cygwin or > Windows which causes this very strange behaviour? Giving us more details about your filesystem would help us answer that question. --=20 Eric Blake eblake AT redhat DOT com +1-801-349-2682 Libvirt virtualization library http://libvirt.org --------------enig5CF67219E832FC4C37D53547 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iQEcBAEBCAAGBQJNJ4OjAAoJEKeha0olJ0NqLr0H/RckzqrpqsD98sU8IpJUdsJP kU2/vRNMkBwrXBG/Y/Q/y6ZA4v9KmVcUwuo0hMVRtvnT2txHGG27OjSobj2aUjw+ mjTZSIKWqH1I46HZ6Bki1YzEyMDc0Qk8sZkpdEgUI5cdobVbQIp8rnMcYj9yX63i D6vXmJsIWMmTkeUr4gltUmAZte10aRyAUr34VV3/fTiO9qSDarM3NKodZE1xYz62 2Gx0hJUDrjrR0I+XlRmwuaM8fU5EH8faGG7gRDKh2u81c6rN8BE3Q2tBllYfFz6d Eby+jApZQx1T/MDqxZSbo8dBU1VnxmNgDvK6wKftjgf7idHUzwXVJ3eocAbZlrQ= =gE95 -----END PGP SIGNATURE----- --------------enig5CF67219E832FC4C37D53547--