Date: Fri, 20 Aug 2010 19:03:27 +0200 From: Ed Schouten <ed@80386.nl> To: Daichi GOTO <daichi@freebsd.org> Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org, ozawa@ongs.co.jp Subject: Whiteout support for tmpfs [Was: unionfs a little improvement] Message-ID: <20100820170327.GL2978@hoeg.nl> In-Reply-To: <4C6B9F51.1060009@freebsd.org> References: <4C6B9F51.1060009@freebsd.org>
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--cW0eHRJ76X8TDo3d Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi all, Even though the proposed fix for unionfs would still be nice to have in SVN, I just wrote a patch for tmpfs to add support for whiteouts: http://80386.nl/pub/tmpfs-whiteout.txt Basically I've implemented it by allowing directory entries to refer to NULL inodes, to indicate the entry is a whiteout. I think the patch should work pretty well, but what I dislike about it, is that when it removes a file and replaces it by a whiteout, it deallocates the entire directory entry, followed by the allocation of a new directory entry for the whiteout. This could be done more efficiently, but the problem is that it turns the code into a mess. Any comments? --=20 Ed Schouten <ed@80386.nl> WWW: http://80386.nl/ --cW0eHRJ76X8TDo3d Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (FreeBSD) iEYEARECAAYFAkxutV8ACgkQ52SDGA2eCwWV2wCdFgiJwRp3LqMCyav+AJfLHg6b /cIAn2MtKM/AEmxHH7mW7WpdU8dKPMdT =UF2+ -----END PGP SIGNATURE----- --cW0eHRJ76X8TDo3d--
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