[XFS updates] XFS development tree branch, master, updated. v2.6.28-rc3-1829-g2505115

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The branch, master has been updated
  2505115 [XFS] Fix race in xfs_write() between direct and buffered I/O with DMAPI
      from  ad1ad968f4e7b06c75741575ea077e25a87da49a (commit)

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commit 25051158bbed127e8672b43396c71c5eb610e5f1
Author: Lachlan McIlroy <lachlan at redback.melbourne.sgi.com>
Date:   Wed Dec 24 14:07:32 2008 +1100

    [XFS] Fix race in xfs_write() between direct and buffered I/O with DMAPI
    
    The iolock is dropped and re-acquired around the call to XFS_SEND_NAMESP().
    While the iolock is released the file can become cached.  We then
    'goto retry' and - if we are doing direct I/O - mapping->nrpages may now be
    non zero but need_i_mutex will be zero and we will hit the WARN_ON().
    
    Since we have dropped the I/O lock then the file size may have also changed
    so what we need to do here is 'goto start' like we do for the XFS_SEND_DATA()
    DMAPI event.
    
    We also need to update the filesize before releasing the iolock so that
    needs to be done before the XFS_SEND_NAMESP event.  If we drop the iolock
    before setting the filesize we could race with a truncate.
    
    Reviewed-by: Christoph Hellwig <hch at infradead.org>
    Signed-off-by: Lachlan McIlroy <lachlan at sgi.com>

-----------------------------------------------------------------------

Summary of changes:
 fs/xfs/linux-2.6/xfs_lrw.c |   27 ++++++++++++---------------
 1 files changed, 12 insertions(+), 15 deletions(-)


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