Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!umd5!mimsy!chris From: chris@mimsy.UUCP (Chris Torek) Newsgroups: comp.unix.wizards Subject: Re: Delayed writes on removed files Message-ID: <11332@mimsy.UUCP> Date: 3 May 88 16:57:07 GMT References: <13188@brl-adm.ARPA> Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 32 >Amos Shapir : >>... When a file is removed ... [and its] delayed write buffers are >>reallocated, they will be written to the disk, even though their >>contents are no longer relevant. In article <13188@brl-adm.ARPA> rbj@icst-cmr.arpa (Root Boy Jim) writes: >I find this hard to believe. Believe it. In 4.3BSD, though, full blocks are written immediately; only partial blocks are written with B_DELWRI. >If there *are* blocks waiting to be read, Not read---written. >When the file *is* finally closed, ... the system should just ignore >the delayed write flag and move the blocks to the free list. It cannot; the blocks are tagged only by pairs, and the truncation code does not search the cache for each such pair. >Chris, say it ain't so! (Why me?) Anyway, given that writes on full blocks are started immediately via bawrite() (see rwip(), when n+on==bsize), only partial block delayed writes could be avoided, and these are probably rare. Instead of trying to fix it, I say, wait for the `virtual memory filesystem' in 4.4BSD. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris