[nSLUG] EXT3 missing log file

Ben Armstrong synrg at sanctuary.nslug.ns.ca
Tue Feb 9 14:52:17 AST 2010


On Tue, 9 Feb 2010 14:46:01 -0400
mspencer at tallships.ca (Mike Spencer) wrote:
> By "exists", you mean that there is a table entry somewhere in the
> running kernel that lists it as an "existing, open" file, an entry
> which lsof can find and report on?
> 
> But since you haven't issued EOF to the cat command, where does
> further input to the cat command go if there is no "directory entry
> pointing at it"?  Where does output go when it's to an "existing" file
> that has no storage media/capacity associated with it?
> 
> 
> (I've long had a related question about pipes but I'll avoid confusion
> here and ask that question later.)

Maybe dig the answer out of this article?

http://en.wikipedia.org/wiki/Inode

Here's an excerpt that is relevant:

"# An inode can even have no links at all. Normally such a file would
be removed from the disk and its resources freed for reallocation (the
normal process of deleting a file) but if any processes are holding the
file open, they may continue to access it, and the file will only be
finally deleted when the last reference to it is closed. This includes
executable images which are implicitly held open by the processes
executing them. For this reason, when programs are updated, it is
recommended to delete the old executable first and create a new inode
for the updated version, so that any instances of the old version
currently executing may continue to do so unbothered."

Ben
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