On 03/31/2013 07:18 PM, Pavel Machek wrote:
Hi!
Take a look at how many actively used filesystems out there that have
some variant of sillyrename(), and explain what you want to do in those
cases.
Well. Yes, there are non-unix filesystems around. You have to deal
with silly files on them, and this will not be different.
So this would be a local POSIX filesystem only solution to a problem
that has yet to be formulated?
Problem is "clasical create temp file then delete it" is racy. See the
archives. That is useful & common operation.
Which race are you concerned with exactly?
User wants to test for a file with name "foo.txt"
* create "foo.txt~" (or whatever)
* write contents into "foo.txt~"
* rename "foo.txt~" to "foo.txt"
Until rename is done, the file does not exists and is not complete.
You will potentially have a garbage file to clean up if the program
(or system) crashes, but that is not racy in a classic sense, right?
Well. If people rsync from you, they will start fetching incomplete
foo.txt~. Plus the garbage issue.
That is not racy, just garbage (not trying to be pedantic, just trying to
understand). I can see that the "~" file is annoying, but we have dealt with it
for a *long* time :)
Until it has the right name (on either the source or target system for rsync),
it is not the file you are looking for.
This is more of a garbage clean up issue?
Also. Plus sometimes you want temporary "file" that is
deleted. Terminals use it for history, etc...
There you would have a race, you can create a file and unlink it of course and
still write to it, but you would have a potential empty file issue?
Ric
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