[RFC PATCH 7/7] readahead: documentation

[Thiago Rafael Becker <trbecker@gmail.com>]

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <trbecker@gmail.com>
---
 tools/nfs-readahead-udev/Makefile.am          |  2 +
 .../nfs-readahead-udev/nfs-readahead-udev.man | 47 +++++++++++++++++++
 tools/nfs-readahead-udev/readahead.conf       | 14 ++++++
 3 files changed, 63 insertions(+)
 create mode 100644 tools/nfs-readahead-udev/nfs-readahead-udev.man

diff --git a/tools/nfs-readahead-udev/Makefile.am b/tools/nfs-readahead-udev/Makefile.am
index 010350aa..eaa9b90e 100644
--- a/tools/nfs-readahead-udev/Makefile.am
+++ b/tools/nfs-readahead-udev/Makefile.am
@@ -10,6 +10,8 @@ udev_rules_DATA = 99-nfs_bdi.rules
 ra_confdir = $(sysconfdir)
 ra_conf_DATA = readahead.conf
 
+man5_MANS = nfs-readahead-udev.man
+
 99-nfs_bdi.rules: 99-nfs_bdi.rules.in $(builddefs)
 	$(SED) "s|_libexecdir_|@libexecdir@|g" 99-nfs_bdi.rules.in > $@
 
diff --git a/tools/nfs-readahead-udev/nfs-readahead-udev.man b/tools/nfs-readahead-udev/nfs-readahead-udev.man
new file mode 100644
index 00000000..2477d5b3
--- /dev/null
+++ b/tools/nfs-readahead-udev/nfs-readahead-udev.man
@@ -0,0 +1,47 @@
+.\" Manpage for nfs-readahead-udev.
+.nh
+.ad l
+.TH man 5 "08 Mar 2022" "1.0" "nfs-readahead-udev man page"
+.SH NAME
+
+nfs-readahead-udev \- Find the readahead for a given NFS mount
+
+.SH SYNOPSIS
+
+nfs-readahead-udev <device>
+
+.SH DESCRIPTION
+
+\fInfs-readahead-udev\fR is a tool intended to be used with udev to set the \fIread_ahead_kb\fR parameter of NFS mounts, according to the configuration file (see \fICONFIGURATION\fR). \fIdevice\fR is the device number for the NFS backing device as provided by the kernel.
+
+.SH CONFIGURATION
+
+The configuration file (\fI/etc/readahead.conf\fR) contains the readahead configuration, and is formatted as follows.
+
+<LINES> ::= <LINES> <LINE> | <LINE>
+
+<LINE> ::= <TOKENS> <ENDL>
+
+<TOKENS> ::= <TOKENS> <TOKEN> | <TOKEN>
+
+<TOKEN> ::= default | <PAIR>
+
+<PAIR> ::= mountpoint = <mountpoint> | fstype = <nfs|nfs4> | readahead = <readahead>
+
+\fImountpoint\fR is the path in the system where the file system is mounted.
+
+\fIreadahead\fR is an integer to readahead.
+
+\fIfstype\fR is either \fInfs\fR or \fInfs4\fR. 
+
+.SH SEE ALSO
+
+mount.nfs(8), nfs(5), udev(7), bcc-readahead(8)
+
+.SH BUGS
+
+No known bugs.
+
+.SH AUTHOR
+
+Thiago Rafael Becker <trbecker@gmail.com>
diff --git a/tools/nfs-readahead-udev/readahead.conf b/tools/nfs-readahead-udev/readahead.conf
index 988b30c7..bce830f1 100644
--- a/tools/nfs-readahead-udev/readahead.conf
+++ b/tools/nfs-readahead-udev/readahead.conf
@@ -1 +1,15 @@
+# nfs-readahead-udev configuration file.
+#
+# This file configures the readahead for nfs mounts when those are anounced by the kernel.
+# The file is composed on lines that can contain either the default configuration (applied to
+# any nfs mount that does not match any of the other lines) or a combination of
+#   mountpoint=<mountpoint> where mountpoint is the mount point for the file system
+#   fstype=<nfs|nfs4> specifies that this configuration should only apply to a specific nfs
+#     version.
+# Every line must contain a readahead option, with the expected readahead value.
 default				readahead=128
+
+# mountpoint=/mnt		readahead=4194304
+# fstype=nfs			readahead=4194304
+# fstype=nfs4			readahead=4194304
+# mountpoint=/mnt	fstype=nfs4	readahead=4194304
-- 
2.35.1