diff -urN ref/fs/namei.c new/fs/namei.c
--- ref/fs/namei.c	Sat Jun  9 00:04:49 2001
+++ new/fs/namei.c	Tue Jun 12 15:37:51 2001
@@ -418,9 +418,13 @@
 {
 	struct dentry *dentry;
 	struct inode *inode;
-	int err;
+	int err, atomic;
 	unsigned int lookup_flags = nd->flags;
 
+	atomic = 0;
+	if (lookup_flags & LOOKUP_ATOMIC)
+		atomic = 1;
+
 	while (*name=='/')
 		name++;
 	if (!*name)
@@ -489,6 +493,9 @@
 		/* This does the actual lookups.. */
 		dentry = cached_lookup(nd->dentry, &this, LOOKUP_CONTINUE);
 		if (!dentry) {
+			err = -EWOULDBLOCKIO;
+			if (atomic)
+				break;
 			dentry = real_lookup(nd->dentry, &this, LOOKUP_CONTINUE);
 			err = PTR_ERR(dentry);
 			if (IS_ERR(dentry))
@@ -552,6 +559,9 @@
 		}
 		dentry = cached_lookup(nd->dentry, &this, 0);
 		if (!dentry) {
+			err = -EWOULDBLOCKIO;
+			if (atomic)
+				break;
 			dentry = real_lookup(nd->dentry, &this, 0);
 			err = PTR_ERR(dentry);
 			if (IS_ERR(dentry))
@@ -884,6 +894,8 @@
 	
 	if (f & O_DIRECTORY)
 		retval |= LOOKUP_DIRECTORY;
+	if (f & O_ATOMICLOOKUP)
+		retval |= LOOKUP_ATOMIC;
 
 	return retval;
 }
diff -urN ref/include/asm-alpha/fcntl.h new/include/asm-alpha/fcntl.h
--- ref/include/asm-alpha/fcntl.h	Thu Nov 16 15:37:42 2000
+++ new/include/asm-alpha/fcntl.h	Tue Jun 12 15:37:51 2001
@@ -21,6 +21,8 @@
 #define O_DIRECTORY	0100000	/* must be a directory */
 #define O_NOFOLLOW	0200000 /* don't follow links */
 #define O_LARGEFILE	0400000 /* will be set by the kernel on every open */
+#define O_ATOMICLOOKUP  01000000 /* do atomic file lookup */
+
 
 #define F_DUPFD		0	/* dup */
 #define F_GETFD		1	/* get close_on_exec */
diff -urN ref/include/asm-i386/fcntl.h new/include/asm-i386/fcntl.h
--- ref/include/asm-i386/fcntl.h	Tue Jun 12 15:35:04 2001
+++ new/include/asm-i386/fcntl.h	Tue Jun 12 15:37:51 2001
@@ -20,6 +20,7 @@
 #define O_LARGEFILE	0100000
 #define O_DIRECTORY	0200000	/* must be a directory */
 #define O_NOFOLLOW	0400000 /* don't follow links */
+#define O_ATOMICLOOKUP	01000000 /* do atomic file lookup */
 
 #define F_DUPFD		0	/* dup */
 #define F_GETFD		1	/* get close_on_exec */
diff -urN ref/include/asm-ia64/fcntl.h new/include/asm-ia64/fcntl.h
--- ref/include/asm-ia64/fcntl.h	Thu Nov 16 15:37:42 2000
+++ new/include/asm-ia64/fcntl.h	Tue Jun 12 15:37:51 2001
@@ -28,6 +28,7 @@
 #define O_LARGEFILE	0100000
 #define O_DIRECTORY	0200000	/* must be a directory */
 #define O_NOFOLLOW	0400000 /* don't follow links */
+#define O_ATOMICLOOKUP  01000000 /* do atomic file lookup */
 
 #define F_DUPFD		0	/* dup */
 #define F_GETFD		1	/* get close_on_exec */
diff -urN ref/include/asm-sparc/fcntl.h new/include/asm-sparc/fcntl.h
--- ref/include/asm-sparc/fcntl.h	Tue Jun 12 15:35:04 2001
+++ new/include/asm-sparc/fcntl.h	Tue Jun 12 15:39:42 2001
@@ -20,6 +20,7 @@
 #define O_DIRECTORY	0x10000	/* must be a directory */
 #define O_NOFOLLOW	0x20000	/* don't follow links */
 #define O_LARGEFILE	0x40000
+#define O_ATOMICLOOKUP  0x80000 /* do atomic file lookup */
 #define O_DIRECT        0x100000 /* direct disk access hint */
 
 #define F_DUPFD		0	/* dup */
diff -urN ref/include/asm-sparc64/fcntl.h new/include/asm-sparc64/fcntl.h
--- ref/include/asm-sparc64/fcntl.h	Tue Jun 12 15:35:04 2001
+++ new/include/asm-sparc64/fcntl.h	Tue Jun 12 15:39:59 2001
@@ -20,6 +20,7 @@
 #define O_DIRECTORY	0x10000	/* must be a directory */
 #define O_NOFOLLOW	0x20000	/* don't follow links */
 #define O_LARGEFILE	0x40000
+#define O_ATOMICLOOKUP  0x80000 /* do atomic file lookup */
 #define O_DIRECT        0x100000 /* direct disk access hint */
 
 
diff -urN ref/include/linux/errno.h new/include/linux/errno.h
--- ref/include/linux/errno.h	Fri Feb 23 21:20:14 2001
+++ new/include/linux/errno.h	Tue Jun 12 15:37:51 2001
@@ -21,6 +21,9 @@
 #define EBADTYPE	527	/* Type not supported by server */
 #define EJUKEBOX	528	/* Request initiated, but will not complete before timeout */
 
+/* Defined for TUX async IO */
+#define EWOULDBLOCKIO	530	/* Would block due to block-IO */
+
 #endif
 
 #endif
diff -urN ref/include/linux/fs.h new/include/linux/fs.h
--- ref/include/linux/fs.h	Tue Jun 12 15:35:04 2001
+++ new/include/linux/fs.h	Tue Jun 12 15:37:51 2001
@@ -1202,6 +1202,7 @@
 #define LOOKUP_POSITIVE		(8)
 #define LOOKUP_PARENT		(16)
 #define LOOKUP_NOALT		(32)
+#define LOOKUP_ATOMIC		(64)
 /*
  * Type of the last component on LOOKUP_PARENT
  */