xfs: optimize log flushing in xfs_fsync

If we have a pinned inode it must have a log item attached to it.
Usually that log item will have ili_last_lsn already set, in which
case we only need to flush the log up to that LSN instead of doing a
full log force.  This gives speedups of about 5% in some fsync heavy
workloads.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 43241e289800..ddd2c5d1b854 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -629,8 +629,14 @@ xfs_fsync(
                  */
                 xfs_iunlock(ip, XFS_ILOCK_SHARED);
                 if (xfs_ipincount(ip)) {
-                        error = _xfs_log_force(ip->i_mount, XFS_LOG_SYNC,
-                                               &log_flushed);
+                        if (ip->i_itemp->ili_last_lsn) {
+                                error = _xfs_log_force_lsn(ip->i_mount,
+                                                ip->i_itemp->ili_last_lsn,
+                                                XFS_LOG_SYNC, &log_flushed);
+                        } else {
+                                error = _xfs_log_force(ip->i_mount,
+                                                XFS_LOG_SYNC, &log_flushed);
+                        }
                 }
         } else  {
                 /*