OpenAFS Master Repository branch, master, updated. openafs-devel-1_5_76-3126-gad4e634

[Gerrit Code Review]

The following commit has been merged in the master branch:
commit ad4e634051e18fa5bd07016b6405e53e236c2f45
Author: Andrew Deason <adeason@sinenomine.net>
Date:   Wed Nov 14 18:29:35 2012 -0600

    afs: Do not skip flushing pages for dv-0 files
    
    If the dv for a file is 0, we know the file is empty. Currently we
    skip flushing pages for such files, presumably the idea being there is
    no data in the file, so there should be no pages to flush.
    
    However, Linux seems to keep empty pages around for empty files. So, a
    future read can result in the application reading a page full of
    zeroes, unless we flush the page here. While this has only been found
    to happen on Linux 2.6.22 and later (and distribution-specific
    backports, like RHEL 2.6.18-128), other platforms could in theory also
    choose to do this. It would be difficult to find out when another
    platform started to behave like this, so just remove this skip for
    everyone so we never have to deal with this again.
    
    Replace this code with a comment with a quick explanation, in case
    anyone tries to add a similar optimization here in the future.
    
    Thanks to Richard Brittain.
    
    Change-Id: I68c51bb7612a98a5c75112bb8f4bb1edd949fda1
    Reviewed-on: http://gerrit.openafs.org/8465
    Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
    Tested-by: BuildBot <buildbot@rampaginggeek.com>
    Reviewed-by: Derrick Brashear <shadow@your-file-system.com>

 src/afs/afs_osi_vm.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

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