diff --git a/contrib/shrink-revlog.py b/contrib/shrink-revlog.py
--- a/contrib/shrink-revlog.py
+++ b/contrib/shrink-revlog.py
@@ -251,8 +251,8 @@ def shrink(ui, repo, **opts):
         if not opts.get('dry_run'):
             # racy, both files cannot be renamed atomically
             # copy files
-            util.os_link(indexfn, oldindexfn)
-            ignoremissing(util.os_link)(datafn, olddatafn)
+            util.oslink(indexfn, oldindexfn)
+            ignoremissing(util.oslink)(datafn, olddatafn)
 
             # rename
             util.rename(tmpindexfn, indexfn)
diff --git a/hgext/relink.py b/hgext/relink.py
--- a/hgext/relink.py
+++ b/hgext/relink.py
@@ -132,7 +132,7 @@ def do_relink(src, dst, files, ui):
         bak = dst + '.bak'
         os.rename(dst, bak)
         try:
-            util.os_link(src, dst)
+            util.oslink(src, dst)
         except OSError:
             os.rename(bak, dst)
             raise
diff --git a/mercurial/posix.py b/mercurial/posix.py
--- a/mercurial/posix.py
+++ b/mercurial/posix.py
@@ -12,7 +12,7 @@ posixfile = open
 nulldev = '/dev/null'
 normpath = os.path.normpath
 samestat = os.path.samestat
-os_link = os.link
+oslink = os.link
 unlink = os.unlink
 rename = os.rename
 expandglobs = False
diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -435,7 +435,7 @@ def copyfiles(src, dst, hardlink=None):
     else:
         if hardlink:
             try:
-                os_link(src, dst)
+                oslink(src, dst)
             except (IOError, OSError):
                 hardlink = False
                 shutil.copy(src, dst)
@@ -624,7 +624,7 @@ def checknlink(testfile):
     fd = None
     try:
         try:
-            os_link(f1, f2)
+            oslink(f1, f2)
         except OSError:
             return False
 
diff --git a/mercurial/win32.py b/mercurial/win32.py
--- a/mercurial/win32.py
+++ b/mercurial/win32.py
@@ -140,7 +140,7 @@ def _getfileinfo(name):
     finally:
         _kernel32.CloseHandle(fh)
 
-def os_link(src, dst):
+def oslink(src, dst):
     try:
         if not _kernel32.CreateHardLinkA(dst, src, None):
             _raiseoserror(src)