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From: guy@gorodish.Sun.COM (Guy Harris)
Newsgroups: comp.sys.att,comp.unix.wizards
Subject: Re: Wierd 3b inode problem with news.
Message-ID: <33319@sun.uucp>
Date: Sun, 8-Nov-87 18:48:06 EST
Article-I.D.: sun.33319
Posted: Sun Nov  8 18:48:06 1987
Date-Received: Tue, 10-Nov-87 06:04:12 EST
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Keywords: 3b2 inode file system
Xref: mnetor comp.sys.att:1693 comp.unix.wizards:5377

> But in Sys/V, free inodes are also in a linked list, so the
> kernel is dependent on inodes being freed properly.

In the V7 file system, which is used by S5, free inodes are not in any sort of
linked list.  There is a cache in the superblock that saves the i-numbers of a
small number of free inodes.  If this cache is emptied, the system has to make
a linear search through the i-list looking for an inode with a mode word of
zero.  There is an optimization in later versions of this code (including the
S5 version) that tries to remember the i-number of the first free inode, so
that it doesn't have to search the *entire* i-list.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com