diff --git a/ChangeLog.txt b/ChangeLog.txt
index ed9e5fa..3dbf183 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,3 +1,8 @@
+2013-02-16:
+	* (seebs) Add wrapper setting which automatically returns a fixed
+	  value from some wrappers. Add fixed-value wrappers for all the
+	  *sync() functions. These are all contingent on --enable-force-async.
+
 2013-02-15:
 	* (seebs) Add support for in-memory DB. This, plus upcoming
 	  fsync-related changes, are expected to be big enough to justify
diff --git a/Makefile.in b/Makefile.in
index 094deba..8046bda 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -24,6 +24,7 @@ SUFFIX=@SUFFIX@
 SQLITE=@SQLITE@
 SQLITE_LIB=@SQLITE_LIB@
 SQLITE_MEMORY=@SQLITE_MEMORY@
+FORCE_ASYNC=@FORCE_ASYNC@
 BITS=@BITS@
 ARCH_FLAGS=@ARCH_FLAGS@
 MARK64=@MARK64@
@@ -38,7 +39,7 @@ LOCALSTATEDIR=$(PREFIX)/$(LOCALSTATE)
 
 CFLAGS_BASE=-pipe -std=gnu99 -Wall -W -Wextra
 CFLAGS_CODE=-fPIC -D_LARGEFILE64_SOURCE -D_ATFILE_SOURCE $(ARCH_FLAGS)
-CFLAGS_DEFS=-DPSEUDO_PREFIX='"$(PREFIX)"' -DPSEUDO_SUFFIX='"$(SUFFIX)"' -DPSEUDO_BINDIR='"$(BIN)"' -DPSEUDO_LIBDIR='"$(LIB)"' -DPSEUDO_LOCALSTATEDIR='"$(LOCALSTATE)"' -DPSEUDO_VERSION='"$(VERSION)"' $(SQLITE_MEMORY)
+CFLAGS_DEFS=-DPSEUDO_PREFIX='"$(PREFIX)"' -DPSEUDO_SUFFIX='"$(SUFFIX)"' -DPSEUDO_BINDIR='"$(BIN)"' -DPSEUDO_LIBDIR='"$(LIB)"' -DPSEUDO_LOCALSTATEDIR='"$(LOCALSTATE)"' -DPSEUDO_VERSION='"$(VERSION)"' $(SQLITE_MEMORY) $(FORCE_ASYNC)
 CFLAGS_DEBUG=-O2 -g
 CFLAGS_SQL=-L$(SQLITE)/$(SQLITE_LIB) -I$(SQLITE)/include $(RPATH)
 CFLAGS_PSEUDO=$(CFLAGS_BASE) $(CFLAGS_CODE) $(CFLAGS_DEFS) \
diff --git a/configure b/configure
index 44bee74..d88a930 100755
--- a/configure
+++ b/configure
@@ -26,6 +26,7 @@ opt_bits=
 opt_sqlite=/usr
 opt_rpath=
 opt_memory=
+opt_async=
 
 compile_x86_32=-m32
 compile_x86_64=-m64
@@ -37,6 +38,7 @@ usage()
     echo >&2 "           [--libdir=...]"
     echo >&2 "           [--suffix=...]"
     echo >&2 "           [--enable-memory-db]"
+    echo >&2 "           [--enable-force-async]"
     echo >&2 "           [--with-sqlite=...]"
     echo >&2 "           [--with-sqlite-lib=...]"
     echo >&2 "           [--enable-static-sqlite]"
@@ -71,6 +73,12 @@ do
         sqlite_ldarg='$(SQLITE)/$(SQLITE_LIB)/libsqlite3.a'
         use_maybe_rpath=false
         ;;
+    --enable-force-async=no | --disable-force-async)
+        opt_async=false
+        ;;
+    --enable-force-async=yes | --enable-force-async)
+        opt_async=true
+	;;
     --enable-memory-db=no)
         opt_memory=false
         ;;
@@ -178,6 +186,16 @@ if [ "${SQLITE3_VERSION}" -lt "03006000" ]; then
     exit 1
 fi
 
+if [ -z "$opt_async" ]; then
+    opt_async=false
+fi
+
+if $opt_async; then
+    FORCE_ASYNC="-DPSEUDO_FORCE_ASYNC"
+else
+    FORCE_ASYNC=""
+fi
+
 if [ -z "$opt_memory" ]; then
     if [ "${SQLITE3_VERSION}" -lt "03007000" ]; then
         echo "Disabling in-memory database by default (sqlite too old)."
@@ -211,6 +229,7 @@ sed -e '
   s,@SQLITE_LDARG@,'"$sqlite_ldarg"',g
   s,@SQLITE_LIB@,'"$opt_sqlite_lib"',g
   s,@SQLITE_MEMORY@,'"$SQLITE_MEMORY"',g
+  s,@FORCE_ASYNC@,'"$FORCE_ASYNC"',g
   s!@RPATH@!'"$opt_rpath"'!g
   s,@MARK64@,'"$opt_mark64"',g
   s,@ARCH@,'"$opt_arch"',g
diff --git a/guts/COPYRIGHT b/guts/COPYRIGHT
index c96e1b1..85c47c7 100644
--- a/guts/COPYRIGHT
+++ b/guts/COPYRIGHT
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008-2010 Wind River Systems, Inc.
+ * Copyright (c) 2008-2013 Wind River Systems, Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the Lesser GNU General Public License version 2.1 as
diff --git a/makewrappers b/makewrappers
index 168fd81..fb919b5 100755
--- a/makewrappers
+++ b/makewrappers
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 #
-# Copyright (c) 2008-2011 Wind River Systems, Inc.
+# Copyright (c) 2008-2011,2013 Wind River Systems, Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the Lesser GNU General Public License version 2.1 as
@@ -219,6 +219,7 @@ class Function:
         self.paths_to_munge = []
         self.specific_dirfds = {}
         self.hand_wrapped = None
+        self.async_skip = None
         # used for the copyright date when creating stub functions
         self.date = datetime.date.today().year
     
@@ -300,6 +301,16 @@ class Function:
         else:
             return ""
 
+    def maybe_async_skip(self):
+        if self.async_skip:
+	    return """/* This function is not called if pseudo is configured --enable-force-async */
+#ifdef PSEUDO_FORCE_ASYNC
+	return %s;
+#endif
+""" % self.async_skip
+        else:
+	    return ""
+
     def comment(self):
         """declare self (in a comment)"""
         return self.decl(comment = True)
diff --git a/ports/darwin/guts/open.c b/ports/darwin/guts/open.c
index 1ed5882..c66cc15 100644
--- a/ports/darwin/guts/open.c
+++ b/ports/darwin/guts/open.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2012 Wind River Systems; see
+ * Copyright (c) 2011-2013 Wind River Systems; see
  * guts/COPYRIGHT for information.
  *
  * int open(const char *path, int flags, ... { int mode })
@@ -9,6 +9,9 @@
 	struct stat buf = { };
 	int existed = 1;
 	int save_errno;
+#ifdef PSEUDO_FORCE_ASYNCH
+        flags &= ~O_SYNC;
+#endif
 
 	/* if a creation has been requested, check whether file exists */
 	if (flags & O_CREAT) {
diff --git a/ports/linux/guts/openat.c b/ports/linux/guts/openat.c
index 14d6c2a..8460073 100644
--- a/ports/linux/guts/openat.c
+++ b/ports/linux/guts/openat.c
@@ -1,5 +1,5 @@
 /* 
- * Copyright (c) 2008-2010 Wind River Systems; see
+ * Copyright (c) 2008-2010, 2013 Wind River Systems; see
  * guts/COPYRIGHT for information.
  *
  * static int
@@ -16,6 +16,25 @@
 		return -1;
 	}
 #endif
+
+#ifdef PSEUDO_FORCE_ASYNCH
+        /* Yes, I'm aware that every Linux system I've seen has
+         * DSYNC and RSYNC being the same value as SYNC.
+         */
+
+        flags &= ~(O_SYNC
+#ifdef O_DIRECT
+                | O_DIRECT
+#endif
+#ifdef O_DSYNC
+                | O_DSYNC
+#endif
+#ifdef O_RSYNC
+                | O_RSYNC
+#endif
+        );
+#endif
+
 	/* if a creation has been requested, check whether file exists */
 	if (flags & O_CREAT) {
 		save_errno = errno;
diff --git a/ports/unix/guts/fdatasync.c b/ports/unix/guts/fdatasync.c
new file mode 100644
index 0000000..4aa77a8
--- /dev/null
+++ b/ports/unix/guts/fdatasync.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2013 Wind River Systems; see
+ * guts/COPYRIGHT for information.
+ *
+ * int fdatasync(int fd)
+ *	int rc = -1;
+ */
+
+	/* note: wrapper will never call this if PSEUDO_FORCE_ASYNC
+	 * is defined.
+	 */
+	rc = real_fdatasync(fd);
+
+/*	return rc;
+ * }
+ */
diff --git a/ports/unix/guts/fsync.c b/ports/unix/guts/fsync.c
new file mode 100644
index 0000000..6c87a56
--- /dev/null
+++ b/ports/unix/guts/fsync.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2013 Wind River Systems; see
+ * guts/COPYRIGHT for information.
+ *
+ * int fsync(int fd)
+ *	int rc = -1;
+ */
+
+	/* note: wrapper will never call this if PSEUDO_FORCE_ASYNC
+	 * is defined.
+	 */
+	rc = real_fsync(fd);
+
+/*	return rc;
+ * }
+ */
diff --git a/ports/unix/guts/msync.c b/ports/unix/guts/msync.c
new file mode 100644
index 0000000..fbc5e26
--- /dev/null
+++ b/ports/unix/guts/msync.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2013 Wind River Systems; see
+ * guts/COPYRIGHT for information.
+ *
+ * int msync(void *addr, size_t length, int flags)
+ *	int rc = -1;
+ */
+
+	/* note: wrapper will never call this if PSEUDO_FORCE_ASYNC
+	 * is defined.
+	 */
+	rc = real_msync(addr, length, flags);
+
+/*	return rc;
+ * }
+ */
diff --git a/ports/unix/guts/sync.c b/ports/unix/guts/sync.c
new file mode 100644
index 0000000..c5d9554
--- /dev/null
+++ b/ports/unix/guts/sync.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2013 Wind River Systems; see
+ * guts/COPYRIGHT for information.
+ *
+ * void sync(void)
+ *	
+ */
+
+	/* note: wrapper will never call this if PSEUDO_FORCE_ASYNC
+	 * is defined.
+	 */
+	(void) real_sync();
+
+/*	return;
+ * }
+ */
diff --git a/ports/unix/guts/sync_file_range.c b/ports/unix/guts/sync_file_range.c
new file mode 100644
index 0000000..03cfc6c
--- /dev/null
+++ b/ports/unix/guts/sync_file_range.c
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2013 Wind River Systems; see
+ * guts/COPYRIGHT for information.
+ *
+ * int sync_file_range(int fd, off64_t offset, off64_t nbytes, unsigned int flags)
+ *	int rc = -1;
+ */
+
+	rc = real_sync_file_range(fd, offset, nbytes, flags);
+
+/*	return rc;
+ * }
+ */
diff --git a/ports/unix/guts/syncfs.c b/ports/unix/guts/syncfs.c
new file mode 100644
index 0000000..2c9a685
--- /dev/null
+++ b/ports/unix/guts/syncfs.c
@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2013 Wind River Systems; see
+ * guts/COPYRIGHT for information.
+ *
+ * int syncfs(int fd)
+ *	int rc = -1;
+ */
+
+	rc = real_syncfs(fd);
+
+/*	return rc;
+ * }
+ */
diff --git a/ports/unix/wrapfuncs.in b/ports/unix/wrapfuncs.in
index 7e205f0..a0f191c 100644
--- a/ports/unix/wrapfuncs.in
+++ b/ports/unix/wrapfuncs.in
@@ -58,3 +58,12 @@ ssize_t readlink(const char *path, char *buf, size_t bufsiz); /* flags=AT_SYMLIN
 ssize_t readlinkat(int dirfd, const char *path, char *buf, size_t bufsiz); /* flags=AT_SYMLINK_NOFOLLOW */
 int system(const char *command);
 FILE *popen(const char *command, const char *mode); /* hand_wrapped=1 */
+# Based on experiments by Richard Purdie: Allow pseudo to eliminate
+# sync-type operations globally, mostly relevant for performance reasons
+# during filesystem assembly.
+int fsync(int fd); /* async_skip=0 */
+int fdatasync(int fd); /* async_skip=0 */
+void sync(void); /* async_skip=0 */
+int syncfs(int fd); /* async_skip=0 */
+int sync_file_range(int fd, off64_t offset, off64_t nbytes, unsigned int flags); /* async_skip=0 */
+int msync(void *addr, size_t length, int flags); /* async_skip=0 */
diff --git a/templates/wrapfuncs.c b/templates/wrapfuncs.c
index 0d0fb52..86fd557 100644
--- a/templates/wrapfuncs.c
+++ b/templates/wrapfuncs.c
@@ -23,6 +23,8 @@ ${name}(${decl_args}) {
 	${variadic_decl}
 	${rc_decl}
 
+${maybe_async_skip}
+
 	if (!pseudo_check_wrappers() || !real_$name) {
 		/* rc was initialized to the "failure" value */
 		pseudo_enosys("${name}");