[PATCH] uml: implement hostfs syncing

Actually implement the hostfs "sync" method.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/os-Linux/user_syms.c

@@ -83,6 +83,9 @@ EXPORT_SYMBOL_PROTO(statfs64);
 
 EXPORT_SYMBOL_PROTO(getuid);
 
+EXPORT_SYMBOL_PROTO(fsync);
+EXPORT_SYMBOL_PROTO(fdatasync);
+
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
  * Emacs will notice this stuff at the end of the file and automatically

fs/hostfs/hostfs.h

@@ -69,6 +69,7 @@ extern int read_file(int fd, unsigned long long *offset, char *buf, int len);
 extern int write_file(int fd, unsigned long long *offset, const char *buf,
 		      int len);
 extern int lseek_file(int fd, long long offset, int whence);
+extern int fsync_file(int fd, int datasync);
 extern int file_create(char *name, int ur, int uw, int ux, int gr,
 		       int gw, int gx, int or, int ow, int ox);
 extern int set_attr(const char *file, struct hostfs_iattr *attrs);

fs/hostfs/hostfs_kern.c

@@ -382,7 +382,7 @@ int hostfs_file_open(struct inode *ino, struct file *file)
 
 int hostfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 {
-	return(0);
+	return fsync_file(HOSTFS_I(dentry->d_inode)->fd, datasync);
 }
 
 static struct file_operations hostfs_file_fops = {

fs/hostfs/hostfs_user.c

@@ -153,10 +153,24 @@ int lseek_file(int fd, long long offset, int whence)
 	int ret;
 
 	ret = lseek64(fd, offset, whence);
-	if(ret < 0) return(-errno);
+	if(ret < 0)
+		return(-errno);
 	return(0);
 }
 
+int fsync_file(int fd, int datasync)
+{
+	int ret;
+	if (datasync)
+		ret = fdatasync(fd);
+	else
+		ret = fsync(fd);
+
+	if (ret < 0)
+		return -errno;
+	return 0;
+}
+
 void close_file(void *stream)
 {
 	close(*((int *) stream));