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From: Terry Lambert <terry@lambert.org>
Newsgroups: comp.unix.bsd.misc
Subject: Re: Q: fast file system
Date: Tue, 11 Jun 1996 19:38:06 -0700
Organization: Me
Lines: 35
Message-ID: <31BE2D8E.136F432E@lambert.org>
References: <31BDB7F7.41C67EA6@uiuc.edu>
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Vlad wrote:
] In fact I have 2 questions:
]
] (1) Is is true that only files without indirect blocks can have
] the last bit allocated in a fragment ?
If you allocate the last block in a frag, it is no longer a frag,
it's an ordinary block.
] (2) If it's correct to say that block pointers in the inode
] structure point to blocks (not fragments) and distinct
] fragments within the same block can be allocated to different
] files, then how does the file system determine which fragments
] in a given fragmented block belong to which file ? I mean I
] understand that free block bitmaps have granularity on
] the fragment level, but that's not enough: there must be a way
] to specify that, say, first 3 1024-fragments in a 4096-block
] belong to this file associated with this inode and the last
] 1024-fragment belongs to that file/inode...etc.
Only the last fractional block in a file may be contained in
a frag. Ie, you can't have:
block frag frag block frag block frag
You can only have:
block block block block block block frag
Terry Lambert
terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.