Re: [9fans] bind -c

[Keith Nash <kjn9@citizenearth.com>]

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.