Messages in this thread | | | Date | Sat, 30 Mar 2013 20:49:33 +0100 | From | Pavel Machek <> | Subject | Re: New copyfile system call - discuss before LSF? |
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Hi!
> > I thought the first thing people would ask for is to atomically create a > > new file and copy the old file into it (at least on local file systems). > > The idea is that nothing should see an empty destination file, either > > by race or by crash. (This feature would perhaps be described as a > > pony, but it should be implementable.) > > Having already wasted many week trying to implement your pony, I would > consider it about as possible as winning the lottery three times in a > row. It clearly is in theory and yet,...
Hmm, really? AFAICT it would be simple to provide open_deleted_file("directory") syscall. You'd open_deleted_file(), copy source file into it, then fsync(), then link it into filesystem.
That should have atomicity properties reflected. Pavel (who has too many (*) ponies around) (*) 1 is sometimes too many when we talk about big mammals. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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