From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <20030308132205.1201.qmail@mail.dirac.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] bind -c
From: Keith Nash <kjn9@citizenearth.com>
Date: Sat,  8 Mar 2003 13:22:05 +0000
Topicbox-Message-UUID: 7d54d908-eacb-11e9-9e20-41e7f4b1d025

It might be useful to have a 'bind -w' option, that would cause a union member to capture all write operations that would otherwise go to members that are 'after' it.  I suppose the problem is that if a file is opened for reading *and* writing, then the file would first have to be copied to the '-w' member; also the response to file deletion would have to be decided.

'bind -w' might cause more problems than it solves; but it seems sub-optimal that at present, if we want modified files to go to one union member, leaving the originals unchanged in another, we have to perform the 'copy-on-write' operation by manually copying files to a '-c' member - and we must do this (or at least create a file with the right name) even if only write access is required to the file, not read-and-write.  Also, it is obvious that we can only do this manual preparation if we know in advance the names of the files that will be written.

Another useful option might be 'bind -r', to switch off all types of write access to a member, not just file creation.


Keith.