Date: Fri, 15 Mar 2002 15:39:36 -0500 From: Chris Mason <mason@suse.com> To: Terry Lambert <tlambert2@mindspring.com>, Josh MacDonald <jmacd@CS.Berkeley.EDU> Cc: Parity Error <bootup@mail.ru>, freebsd-fs@FreeBSD.ORG, reiserfs-dev@namesys.com Subject: Re: [reiserfs-dev] Re: metadata update durability ordering/soft updates Message-ID: <1562810000.1016224776@tiny> In-Reply-To: <3C923C91.454D7710@mindspring.com> References: <E16lReK-000C3T-00@f10.mail.ru> <3C910C57.71C2D823@mindspring.com> <20020315065651.02637@helen.CS.Berkeley.EDU> <3C923C91.454D7710@mindspring.com>
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On Friday, March 15, 2002 10:25:21 AM -0800 Terry Lambert <tlambert2@mindspring.com> wrote: > Josh MacDonald wrote: >> Terry, >> >> I'm not sure what you're talking about with regards to DOW and >> ReiserFS. It doesn't sound right, and I'm pretty sure we're not using >> anything like the patented DOW technique as you've described it. > > As usual, the patent claims are general enough to cover things; > see: > > US: 5666532 > US: 5642501 > > Here is the USPTO patent number search engine: > > http://164.195.100.11/netahtml/srchnum.htm > I haven't read the entire patent, but maybe you can point me to the paragraphs where it covers write-ahead logging in the description. Durning any operation, no attempt at all is made to order the writing of the bitmap, the inode, the directory entries, or any other part of the metadata. It simply makes sure that after a crash the operations are either completed or not. If you mkdir foo and then mkdir foo2, it is entirely possible the blocks for foo2 go to disk first. The reiserfs log is also not a generic system module loosely coupled from with the rest of the filesystem. -chris To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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