diff --git a/Documentation/git.txt b/Documentation/git.txt
index bf1b45eef1..aa62083209 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -531,10 +531,14 @@ git so take care if using Cogito etc.
 	(Useful for excluding slow-loading network directories.)
 
 'GIT_ONE_FILESYSTEM'::
-	If set to a true value ("true" or a non-zero integer), stop at
-	filesystem boundaries when looking for a repository directory.
-	Like 'GIT_CEILING_DIRECTORIES', it will not affect an explicit
-	respository directory set via 'GIT_DIR' or on the command line.
+	When run in a directory that does not have ".git" repository
+	directory, git tries to find such a directory in the parent
+	directories to find the top of the working tree, but by default it
+	does not cross filesystem boundaries.  This environment variable
+	can be set to false value ("false" or zero) to tell git not to
+	stop at filesystem boundaries.  Like 'GIT_CEILING_DIRECTORIES',
+	this will not affect an explicit respository directory set via
+	'GIT_DIR' or on the command line.
 
 git Commits
 ~~~~~~~~~~~
diff --git a/setup.c b/setup.c
index 8b911b1a38..d290633490 100644
--- a/setup.c
+++ b/setup.c
@@ -323,7 +323,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 	const char *gitdirenv;
 	const char *gitfile_dir;
 	int len, offset, ceil_offset, root_len;
-	int current_device = 0, one_filesystem = 0;
+	int current_device = 0, one_filesystem = 1;
 	struct stat buf;
 
 	/*
@@ -444,7 +444,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
 				}
 				cwd[offset] = '\0';
 				die("Not a git repository (or any parent up to mount parent %s)\n"
-					"Stopping at filesystem boundary since GIT_ONE_FILESYSTEM is set.", cwd);
+				"Stopping at filesystem boundary since GIT_ONE_FILESYSTEM is true.", cwd);
 			}
 		}
 		if (chdir("..")) {