Inode table

[Lennart Sorensen]

On Thu, Jan 13, 2005 at 03:51:39PM -0500, David Kreuter wrote:
> hmm - not sure on this - my understanding is that a certain amount of 
> inodes are kept in memory. The inode for the root of the file system is 
> pointed at by the vfs superblock.  My question is how is the in codre 
> indoe table kept.

I suspect the only thing really kept in memory is by the kernel's
caching of raw disc blocks, which avoids a whole lot of complications at
higher levels as everything above can just read the disc everytime they
need to look something up but will just get an instant response from the
block cache layer rather than having to wait for disk, and writes get
flushed to disk fairly frequently to avoid the disk getting too out of
sync with what the system wants it to contain.  Of course any program
that does a sync to flush a file, will only have it's function return
after the data is actualyl flushed to the disk and no longer just in
memory.  Trying to make a cache system for storing the inodes of
different filesystems in memory would just complicate things since they
have to be searched through anyhow, so why not just parse the data as it
comes from disk each time you need it and cache the raw data.  It's much
simpler that way and it allows one cache system to be used by the whole
system.

Lennart Sorensen
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