From: Lachlan McIlroy Date: Wed, 24 Dec 2008 03:07:32 +0000 (+1100) Subject: [XFS] Fix race in xfs_write() between direct and buffered I/O with DMAPI X-Git-Tag: v2.6.29-rc1~552^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=25051158bbed127e8672b43396c71c5eb610e5f1;p=pandora-kernel.git [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 Signed-off-by: Lachlan McIlroy --- Reading git-diff-tree failed