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file_chmod in unionfs, copy-on-write
From: |
Moritz Schulte |
Subject: |
file_chmod in unionfs, copy-on-write |
Date: |
Thu, 21 Nov 2002 17:20:23 +0100 |
User-agent: |
Gnus/5.090008 (Oort Gnus v0.08) Emacs/21.2 (i686-pc-linux-gnu) |
Hi,
just out of curiosity: how should the yet-to-be-written unionfs
implement copy-on-write for file_chmod()?
unionfs usually gives out ports to the underlying files; when in
copy-on-write mode, it should give out a port to which the user can
safely write without modifying the `real' data. In my understanding
this works, since unionfs notices at open time that the user intents
to write to the file (the O_WRITE flag is specified).
But for file_chmod there is no O_WRITE needed, therefore unionfs is
not able to detect this `write'.
moritz
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moritz@duesseldorf.ccc.de - http://duesseldorf.ccc.de/~moritz/
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- file_chmod in unionfs, copy-on-write,
Moritz Schulte <=