diff --git a/mercurial/osutil.c b/mercurial/osutil.c
--- a/mercurial/osutil.c
+++ b/mercurial/osutil.c
@@ -795,290 +795,284 @@ static PyObject *setprocname(PyObject *s
 #endif /* ndef SETPROCNAME_USE_NONE */
 
 #if defined(HAVE_BSD_STATFS) || defined(HAVE_LINUX_STATFS)
-/* given a directory path, return filesystem type (best-effort), or None */
-const char *getfstype(const char *path) {
-#ifdef HAVE_BSD_STATFS
-	/* need to return a string field */
-	static struct statfs buf;
-#else
-	struct statfs buf;
-#endif
+/* given a directory path and a zero-initialized statfs buffer, return
+ * filesystem type name (best-effort), or NULL. */
+const char *getfstype(const char *path, struct statfs *pbuf) {
 	int r;
-	memset(&buf, 0, sizeof(buf));
-	r = statfs(path, &buf);
+	r = statfs(path, pbuf);
 	if (r != 0)
 		return NULL;
 #if defined(HAVE_BSD_STATFS)
 	/* BSD or OSX provides a f_fstypename field */
-	return buf.f_fstypename;
+	return pbuf->f_fstypename;
 #elif defined(HAVE_LINUX_STATFS)
 	/* Begin of Linux filesystems */
 #ifdef ADFS_SUPER_MAGIC
-	if (buf.f_type == ADFS_SUPER_MAGIC)
+	if (pbuf->f_type == ADFS_SUPER_MAGIC)
 		return "adfs";
 #endif
 #ifdef AFFS_SUPER_MAGIC
-	if (buf.f_type == AFFS_SUPER_MAGIC)
+	if (pbuf->f_type == AFFS_SUPER_MAGIC)
 		return "affs";
 #endif
 #ifdef BDEVFS_MAGIC
-	if (buf.f_type == BDEVFS_MAGIC)
+	if (pbuf->f_type == BDEVFS_MAGIC)
 		return "bdevfs";
 #endif
 #ifdef BEFS_SUPER_MAGIC
-	if (buf.f_type == BEFS_SUPER_MAGIC)
+	if (pbuf->f_type == BEFS_SUPER_MAGIC)
 		return "befs";
 #endif
 #ifdef BFS_MAGIC
-	if (buf.f_type == BFS_MAGIC)
+	if (pbuf->f_type == BFS_MAGIC)
 		return "bfs";
 #endif
 #ifdef BINFMTFS_MAGIC
-	if (buf.f_type == BINFMTFS_MAGIC)
+	if (pbuf->f_type == BINFMTFS_MAGIC)
 		return "binfmtfs";
 #endif
 #ifdef BTRFS_SUPER_MAGIC
-	if (buf.f_type == BTRFS_SUPER_MAGIC)
+	if (pbuf->f_type == BTRFS_SUPER_MAGIC)
 		return "btrfs";
 #endif
 #ifdef CGROUP_SUPER_MAGIC
-	if (buf.f_type == CGROUP_SUPER_MAGIC)
+	if (pbuf->f_type == CGROUP_SUPER_MAGIC)
 		return "cgroup";
 #endif
 #ifdef CIFS_MAGIC_NUMBER
-	if (buf.f_type == CIFS_MAGIC_NUMBER)
+	if (pbuf->f_type == CIFS_MAGIC_NUMBER)
 		return "cifs";
 #endif
 #ifdef CODA_SUPER_MAGIC
-	if (buf.f_type == CODA_SUPER_MAGIC)
+	if (pbuf->f_type == CODA_SUPER_MAGIC)
 		return "coda";
 #endif
 #ifdef COH_SUPER_MAGIC
-	if (buf.f_type == COH_SUPER_MAGIC)
+	if (pbuf->f_type == COH_SUPER_MAGIC)
 		return "coh";
 #endif
 #ifdef CRAMFS_MAGIC
-	if (buf.f_type == CRAMFS_MAGIC)
+	if (pbuf->f_type == CRAMFS_MAGIC)
 		return "cramfs";
 #endif
 #ifdef DEBUGFS_MAGIC
-	if (buf.f_type == DEBUGFS_MAGIC)
+	if (pbuf->f_type == DEBUGFS_MAGIC)
 		return "debugfs";
 #endif
 #ifdef DEVFS_SUPER_MAGIC
-	if (buf.f_type == DEVFS_SUPER_MAGIC)
+	if (pbuf->f_type == DEVFS_SUPER_MAGIC)
 		return "devfs";
 #endif
 #ifdef DEVPTS_SUPER_MAGIC
-	if (buf.f_type == DEVPTS_SUPER_MAGIC)
+	if (pbuf->f_type == DEVPTS_SUPER_MAGIC)
 		return "devpts";
 #endif
 #ifdef EFIVARFS_MAGIC
-	if (buf.f_type == EFIVARFS_MAGIC)
+	if (pbuf->f_type == EFIVARFS_MAGIC)
 		return "efivarfs";
 #endif
 #ifdef EFS_SUPER_MAGIC
-	if (buf.f_type == EFS_SUPER_MAGIC)
+	if (pbuf->f_type == EFS_SUPER_MAGIC)
 		return "efs";
 #endif
 #ifdef EXT_SUPER_MAGIC
-	if (buf.f_type == EXT_SUPER_MAGIC)
+	if (pbuf->f_type == EXT_SUPER_MAGIC)
 		return "ext";
 #endif
 #ifdef EXT2_OLD_SUPER_MAGIC
-	if (buf.f_type == EXT2_OLD_SUPER_MAGIC)
+	if (pbuf->f_type == EXT2_OLD_SUPER_MAGIC)
 		return "ext2";
 #endif
 #ifdef EXT2_SUPER_MAGIC
-	if (buf.f_type == EXT2_SUPER_MAGIC)
+	if (pbuf->f_type == EXT2_SUPER_MAGIC)
 		return "ext2";
 #endif
 #ifdef EXT3_SUPER_MAGIC
-	if (buf.f_type == EXT3_SUPER_MAGIC)
+	if (pbuf->f_type == EXT3_SUPER_MAGIC)
 		return "ext3";
 #endif
 #ifdef EXT4_SUPER_MAGIC
-	if (buf.f_type == EXT4_SUPER_MAGIC)
+	if (pbuf->f_type == EXT4_SUPER_MAGIC)
 		return "ext4";
 #endif
 #ifdef FUSE_SUPER_MAGIC
-	if (buf.f_type == FUSE_SUPER_MAGIC)
+	if (pbuf->f_type == FUSE_SUPER_MAGIC)
 		return "fuse";
 #endif
 #ifdef FUTEXFS_SUPER_MAGIC
-	if (buf.f_type == FUTEXFS_SUPER_MAGIC)
+	if (pbuf->f_type == FUTEXFS_SUPER_MAGIC)
 		return "futexfs";
 #endif
 #ifdef HFS_SUPER_MAGIC
-	if (buf.f_type == HFS_SUPER_MAGIC)
+	if (pbuf->f_type == HFS_SUPER_MAGIC)
 		return "hfs";
 #endif
 #ifdef HOSTFS_SUPER_MAGIC
-	if (buf.f_type == HOSTFS_SUPER_MAGIC)
+	if (pbuf->f_type == HOSTFS_SUPER_MAGIC)
 		return "hostfs";
 #endif
 #ifdef HPFS_SUPER_MAGIC
-	if (buf.f_type == HPFS_SUPER_MAGIC)
+	if (pbuf->f_type == HPFS_SUPER_MAGIC)
 		return "hpfs";
 #endif
 #ifdef HUGETLBFS_MAGIC
-	if (buf.f_type == HUGETLBFS_MAGIC)
+	if (pbuf->f_type == HUGETLBFS_MAGIC)
 		return "hugetlbfs";
 #endif
 #ifdef ISOFS_SUPER_MAGIC
-	if (buf.f_type == ISOFS_SUPER_MAGIC)
+	if (pbuf->f_type == ISOFS_SUPER_MAGIC)
 		return "isofs";
 #endif
 #ifdef JFFS2_SUPER_MAGIC
-	if (buf.f_type == JFFS2_SUPER_MAGIC)
+	if (pbuf->f_type == JFFS2_SUPER_MAGIC)
 		return "jffs2";
 #endif
 #ifdef JFS_SUPER_MAGIC
-	if (buf.f_type == JFS_SUPER_MAGIC)
+	if (pbuf->f_type == JFS_SUPER_MAGIC)
 		return "jfs";
 #endif
 #ifdef MINIX_SUPER_MAGIC
-	if (buf.f_type == MINIX_SUPER_MAGIC)
+	if (pbuf->f_type == MINIX_SUPER_MAGIC)
 		return "minix";
 #endif
 #ifdef MINIX2_SUPER_MAGIC
-	if (buf.f_type == MINIX2_SUPER_MAGIC)
+	if (pbuf->f_type == MINIX2_SUPER_MAGIC)
 		return "minix2";
 #endif
 #ifdef MINIX3_SUPER_MAGIC
-	if (buf.f_type == MINIX3_SUPER_MAGIC)
+	if (pbuf->f_type == MINIX3_SUPER_MAGIC)
 		return "minix3";
 #endif
 #ifdef MQUEUE_MAGIC
-	if (buf.f_type == MQUEUE_MAGIC)
+	if (pbuf->f_type == MQUEUE_MAGIC)
 		return "mqueue";
 #endif
 #ifdef MSDOS_SUPER_MAGIC
-	if (buf.f_type == MSDOS_SUPER_MAGIC)
+	if (pbuf->f_type == MSDOS_SUPER_MAGIC)
 		return "msdos";
 #endif
 #ifdef NCP_SUPER_MAGIC
-	if (buf.f_type == NCP_SUPER_MAGIC)
+	if (pbuf->f_type == NCP_SUPER_MAGIC)
 		return "ncp";
 #endif
 #ifdef NFS_SUPER_MAGIC
-	if (buf.f_type == NFS_SUPER_MAGIC)
+	if (pbuf->f_type == NFS_SUPER_MAGIC)
 		return "nfs";
 #endif
 #ifdef NILFS_SUPER_MAGIC
-	if (buf.f_type == NILFS_SUPER_MAGIC)
+	if (pbuf->f_type == NILFS_SUPER_MAGIC)
 		return "nilfs";
 #endif
 #ifdef NTFS_SB_MAGIC
-	if (buf.f_type == NTFS_SB_MAGIC)
+	if (pbuf->f_type == NTFS_SB_MAGIC)
 		return "ntfs-sb";
 #endif
 #ifdef OCFS2_SUPER_MAGIC
-	if (buf.f_type == OCFS2_SUPER_MAGIC)
+	if (pbuf->f_type == OCFS2_SUPER_MAGIC)
 		return "ocfs2";
 #endif
 #ifdef OPENPROM_SUPER_MAGIC
-	if (buf.f_type == OPENPROM_SUPER_MAGIC)
+	if (pbuf->f_type == OPENPROM_SUPER_MAGIC)
 		return "openprom";
 #endif
 #ifdef PIPEFS_MAGIC
-	if (buf.f_type == PIPEFS_MAGIC)
+	if (pbuf->f_type == PIPEFS_MAGIC)
 		return "pipefs";
 #endif
 #ifdef PROC_SUPER_MAGIC
-	if (buf.f_type == PROC_SUPER_MAGIC)
+	if (pbuf->f_type == PROC_SUPER_MAGIC)
 		return "proc";
 #endif
 #ifdef PSTOREFS_MAGIC
-	if (buf.f_type == PSTOREFS_MAGIC)
+	if (pbuf->f_type == PSTOREFS_MAGIC)
 		return "pstorefs";
 #endif
 #ifdef QNX4_SUPER_MAGIC
-	if (buf.f_type == QNX4_SUPER_MAGIC)
+	if (pbuf->f_type == QNX4_SUPER_MAGIC)
 		return "qnx4";
 #endif
 #ifdef QNX6_SUPER_MAGIC
-	if (buf.f_type == QNX6_SUPER_MAGIC)
+	if (pbuf->f_type == QNX6_SUPER_MAGIC)
 		return "qnx6";
 #endif
 #ifdef RAMFS_MAGIC
-	if (buf.f_type == RAMFS_MAGIC)
+	if (pbuf->f_type == RAMFS_MAGIC)
 		return "ramfs";
 #endif
 #ifdef REISERFS_SUPER_MAGIC
-	if (buf.f_type == REISERFS_SUPER_MAGIC)
+	if (pbuf->f_type == REISERFS_SUPER_MAGIC)
 		return "reiserfs";
 #endif
 #ifdef ROMFS_MAGIC
-	if (buf.f_type == ROMFS_MAGIC)
+	if (pbuf->f_type == ROMFS_MAGIC)
 		return "romfs";
 #endif
 #ifdef SELINUX_MAGIC
-	if (buf.f_type == SELINUX_MAGIC)
+	if (pbuf->f_type == SELINUX_MAGIC)
 		return "selinux";
 #endif
 #ifdef SMACK_MAGIC
-	if (buf.f_type == SMACK_MAGIC)
+	if (pbuf->f_type == SMACK_MAGIC)
 		return "smack";
 #endif
 #ifdef SMB_SUPER_MAGIC
-	if (buf.f_type == SMB_SUPER_MAGIC)
+	if (pbuf->f_type == SMB_SUPER_MAGIC)
 		return "smb";
 #endif
 #ifdef SOCKFS_MAGIC
-	if (buf.f_type == SOCKFS_MAGIC)
+	if (pbuf->f_type == SOCKFS_MAGIC)
 		return "sockfs";
 #endif
 #ifdef SQUASHFS_MAGIC
-	if (buf.f_type == SQUASHFS_MAGIC)
+	if (pbuf->f_type == SQUASHFS_MAGIC)
 		return "squashfs";
 #endif
 #ifdef SYSFS_MAGIC
-	if (buf.f_type == SYSFS_MAGIC)
+	if (pbuf->f_type == SYSFS_MAGIC)
 		return "sysfs";
 #endif
 #ifdef SYSV2_SUPER_MAGIC
-	if (buf.f_type == SYSV2_SUPER_MAGIC)
+	if (pbuf->f_type == SYSV2_SUPER_MAGIC)
 		return "sysv2";
 #endif
 #ifdef SYSV4_SUPER_MAGIC
-	if (buf.f_type == SYSV4_SUPER_MAGIC)
+	if (pbuf->f_type == SYSV4_SUPER_MAGIC)
 		return "sysv4";
 #endif
 #ifdef TMPFS_MAGIC
-	if (buf.f_type == TMPFS_MAGIC)
+	if (pbuf->f_type == TMPFS_MAGIC)
 		return "tmpfs";
 #endif
 #ifdef UDF_SUPER_MAGIC
-	if (buf.f_type == UDF_SUPER_MAGIC)
+	if (pbuf->f_type == UDF_SUPER_MAGIC)
 		return "udf";
 #endif
 #ifdef UFS_MAGIC
-	if (buf.f_type == UFS_MAGIC)
+	if (pbuf->f_type == UFS_MAGIC)
 		return "ufs";
 #endif
 #ifdef USBDEVICE_SUPER_MAGIC
-	if (buf.f_type == USBDEVICE_SUPER_MAGIC)
+	if (pbuf->f_type == USBDEVICE_SUPER_MAGIC)
 		return "usbdevice";
 #endif
 #ifdef V9FS_MAGIC
-	if (buf.f_type == V9FS_MAGIC)
+	if (pbuf->f_type == V9FS_MAGIC)
 		return "v9fs";
 #endif
 #ifdef VXFS_SUPER_MAGIC
-	if (buf.f_type == VXFS_SUPER_MAGIC)
+	if (pbuf->f_type == VXFS_SUPER_MAGIC)
 		return "vxfs";
 #endif
 #ifdef XENFS_SUPER_MAGIC
-	if (buf.f_type == XENFS_SUPER_MAGIC)
+	if (pbuf->f_type == XENFS_SUPER_MAGIC)
 		return "xenfs";
 #endif
 #ifdef XENIX_SUPER_MAGIC
-	if (buf.f_type == XENIX_SUPER_MAGIC)
+	if (pbuf->f_type == XENIX_SUPER_MAGIC)
 		return "xenix";
 #endif
 #ifdef XFS_SUPER_MAGIC
-	if (buf.f_type == XFS_SUPER_MAGIC)
+	if (pbuf->f_type == XFS_SUPER_MAGIC)
 		return "xfs";
 #endif
 	/* End of Linux filesystems */
@@ -1089,10 +1083,12 @@ const char *getfstype(const char *path) 
 static PyObject *pygetfstype(PyObject *self, PyObject *args)
 {
 	const char *path = NULL;
+	struct statfs buf;
 	if (!PyArg_ParseTuple(args, "s", &path))
 		return NULL;
 
-	const char *type = getfstype(path);
+	memset(&buf, 0, sizeof(buf));
+	const char *type = getfstype(path, &buf);
 	if (type == NULL)
 		Py_RETURN_NONE;