Re: [PATCH 0/3] Fixing volatile HEAD in push.default = current

On Thu, 23 May 2013 13:25:55 +0000, Ramkumar Ramachandra wrote:

Junio C Hamano wrote:

quoted

    I have "largedir" I want to get rid of, but there is a directory
    I want to save, "largedir/precious", in it, so I do

        cp -R largedir/precious precious

    and then run 'rm -rf largedir' in another terminal in parallel.

'mv largedir/precious precious; rm -rf largedir'? No race here.

...

Consider a slightly different example: I rename a file while having an
active file handle open in a process that's reading the file.  Will
the rename fail or will the fread() in the process fail?  Nope, both
work fine.  Replace "rename" with "remove", and we still have the same
answer.  Ofcourse there are no guarantees: I can start up another
process to overwrite the sectors corresponding to that file's data
with zeros; unless the complete file is there in the kernel buffer, a
read() will eventually end up slurping in the zeros (or fail?), right?

Oh, there are guarantees, they just don't include the case where you
take a shotgun to the disk. (Or do it on an nfs mount and delete the
file from another machine.)

...

Andreas

-- 
"Totally trivial. Famous last words."
From: Linus Torvalds <torvalds@*.org>
Date: Fri, 22 Jan 2010 07:29:21 -0800