svn commit: r277503 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs

[Will Andrews]

Author: will
Date: Wed Jan 21 19:25:57 2015
New Revision: 277503
URL: https://svnweb.freebsd.org/changeset/base/277503

Log:
  Ignore sync requests from the system syncher, i.e. VFS_SYNC(waitfor=MNT_LAZY).
  
  ZFS already commits outstanding data every zfs_txg_timeout seconds, so these
  syncs are unnecessarily intrusive.
  
  Submitted by:	gibbs
  Sponsored by:	Spectra Logic
  MFSpectraBSD:	1105759 on 2014/12/11

Modified:
  head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c

Modified: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c
==============================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c	Wed Jan 21 19:23:46 2015	(r277502)
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c	Wed Jan 21 19:25:57 2015	(r277503)
@@ -132,6 +132,13 @@ zfs_sync(vfs_t *vfsp, int waitfor)
 	if (panicstr)
 		return (0);
 
+	/*
+	 * Ignore the system syncher.  ZFS already commits async data
+	 * at zfs_txg_timeout intervals.
+	 */
+	if (waitfor == MNT_LAZY)
+		return (0);
+
 	if (vfsp != NULL) {
 		/*
 		 * Sync a specific filesystem.