xfs: reimplement fdatasync support

Add an in-memory only flag to say we logged timestamps only, and use it to
check if fdatasync can optimize away the log force.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 8becef4f9e6..05d924efcea 100644
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -438,7 +438,8 @@ out:
          * games in recovery easier, which isn't a big deal as just about any
          * transaction would dirty it anyway.
          */
-        iip->ili_format.ilf_fields = XFS_ILOG_CORE | iip->ili_fields;
+        iip->ili_format.ilf_fields = XFS_ILOG_CORE |
+                (iip->ili_fields & ~XFS_ILOG_TIMESTAMP);
         iip->ili_format.ilf_size = nvecs;
 }