filesystems.5: Mention sysfs(2)

* man5/filesystems.5 (.SH DESCRIPTION): Add a note that the
  information about available file systems can be obtained
  via sysfs() syscall.

Signed-off-by: Eugene Syromyatnikov <evgsyr@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man5/filesystems.5 b/man5/filesystems.5
index 15fb7dd03b54ebef8128b08fe7ee0561315f230e..0c42c6c75c7a9e096c1d17485c7b7062e1c6d276 100644 (file)
--- a/man5/filesystems.5
+++ b/man5/filesystems.5
@@ -42,10 +42,21 @@ see
 for more details.
 If you need a currently unsupported filesystem, insert the corresponding
 module or recompile the kernel.
+There is also a legacy
+.BR sysfs (2)
+system call (availability of which is controlled by the
+.\" commit: 6af9f7bf3c399e0ab1eee048e13572c6d4e15fe9
+.B CONFIG_SYSFS_SYSCALL
+kernel build configuration option since Linux 3.15)
+that enables enumeration of currently available filesystem types regardless of
+.I /proc
+availability and/or sanity.
 .PP
 In order to use a filesystem, you have to
 .I mount
 it; see
+.BR mount (2)
+and
 .BR mount (8).
 .PP
 Below a short description of the available or historically available