From a27a263bae072a499acc77b632238a6dacccf888 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 16 Jun 2011 12:02:23 +0000 Subject: xfs: make log devices with write back caches work There's no reason not to support cache flushing on external log devices. The only thing this really requires is flushing the data device first both in fsync and log commits. A side effect is that we also have to remove the barrier write test during mount, which has been superflous since the new FLUSH+FUA code anyway. Also use the chance to flush the RT subvolume write cache before the fsync commit, which is required for correct semantics. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder --- fs/xfs/xfs_log.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 211930246f20..41d5b8f2bf92 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -1372,8 +1372,17 @@ xlog_sync(xlog_t *log, XFS_BUF_ASYNC(bp); bp->b_flags |= XBF_LOG_BUFFER; - if (log->l_mp->m_flags & XFS_MOUNT_BARRIER) + if (log->l_mp->m_flags & XFS_MOUNT_BARRIER) { + /* + * If we have an external log device, flush the data device + * before flushing the log to make sure all meta data + * written back from the AIL actually made it to disk + * before writing out the new log tail LSN in the log buffer. + */ + if (log->l_mp->m_logdev_targp != log->l_mp->m_ddev_targp) + xfs_blkdev_issue_flush(log->l_mp->m_ddev_targp); XFS_BUF_ORDERED(bp); + } ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1); ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize); -- cgit v1.2.3