diff --git a/.gitignore b/.gitignore

index e97b31f5..e504d492 100644

--- a/.gitignore

+++ b/.gitignore

@@ -60,6 +60,8 @@ utils/statd/statd

 tools/locktest/testlk

 tools/getiversion/getiversion

 tools/nfsconf/nfsconf

+tools/nfsrahead/nfsrahead

+tools/nfsrahead/99-nfs_bdi.rules

 support/export/mount.h

 support/export/mount_clnt.c

 support/export/mount_xdr.c

diff --git a/configure.ac b/configure.ac

index 6d464ac5..f462a645 100644

--- a/configure.ac

+++ b/configure.ac

@@ -639,6 +639,7 @@ AC_CONFIG_FILES([

 	tools/rpcgen/Makefile

 	tools/mountstats/Makefile

 	tools/nfs-iostat/Makefile

+	tools/nfsrahead/Makefile

 	tools/rpcctl/Makefile

 	tools/nfsdclnts/Makefile

 	tools/nfsconf/Makefile

diff --git a/nfs.conf b/nfs.conf

index 86ed7d53..30f9e109 100644

--- a/nfs.conf

+++ b/nfs.conf

@@ -5,6 +5,10 @@

 [general]

 # pipefs-directory=/var/lib/nfs/rpc_pipefs

 #

+[nfsrahead]

+# nfs=15000

+# nfs4=16000

+#

 [exportfs]

 # debug=0

 #

diff --git a/systemd/nfs.conf.man b/systemd/nfs.conf.man

index f32c690b..ebbf28d0 100644

--- a/systemd/nfs.conf.man

+++ b/systemd/nfs.conf.man

@@ -245,6 +245,17 @@ Only

 .B debug=

 is recognized.

+.TP

+.B nfsrahead

+Recognized values:

+.BR nfs ,

+.BR nfsv4 ,

+.BR default .

+

+See

+.BR nfsrahead (5)

+for deatils.

+

 .SH FILES

 .I /etc/nfs.conf

 .SH SEE ALSO

diff --git a/tools/Makefile.am b/tools/Makefile.am

index c3feabbe..40c17c37 100644

--- a/tools/Makefile.am

+++ b/tools/Makefile.am

@@ -12,6 +12,6 @@ if CONFIG_NFSDCLD

 OPTDIRS += nfsdclddb

 endif

-SUBDIRS = locktest rpcdebug nlmtest mountstats nfs-iostat rpcctl nfsdclnts $(OPTDIRS)

+SUBDIRS = locktest rpcdebug nlmtest mountstats nfs-iostat rpcctl nfsdclnts nfsrahead $(OPTDIRS)

 MAINTAINERCLEANFILES = Makefile.in

diff --git a/tools/nfsrahead/99-nfs.rules b/tools/nfsrahead/99-nfs.rules

new file mode 100644

index 00000000..c74914b2

--- /dev/null

+++ b/tools/nfsrahead/99-nfs.rules

@@ -0,0 +1 @@

+SUBSYSTEM=="bdi", ACTION=="add", PROGRAM="/usr/libexec/nfsrahead %k", ATTR{read_ahead_kb}="%c"

diff --git a/tools/nfsrahead/99-nfs.rules.in b/tools/nfsrahead/99-nfs.rules.in

new file mode 100644

index 00000000..648813c5

--- /dev/null

+++ b/tools/nfsrahead/99-nfs.rules.in

@@ -0,0 +1 @@

+SUBSYSTEM=="bdi", ACTION=="add", PROGRAM="_libexecdir_/nfsrahead %k", ATTR{read_ahead_kb}="%c"

diff --git a/tools/nfsrahead/Makefile.am b/tools/nfsrahead/Makefile.am

new file mode 100644

index 00000000..845ea0d5

--- /dev/null

+++ b/tools/nfsrahead/Makefile.am

@@ -0,0 +1,16 @@

+libexec_PROGRAMS = nfsrahead

+nfsrahead_SOURCES = main.c

+nfsrahead_LDFLAGS= -lmount

+nfsrahead_LDADD = ../../support/nfs/libnfsconf.la

+

+man5_MANS = nfsrahead.man

+EXTRA_DIST = $(man5_MANS)

+

+udev_rulesdir = /usr/lib/udev/rules.d/

+udev_rules_DATA = 99-nfs.rules

+

+99-nfs.rules: 99-nfs.rules.in $(builddefs)

+	$(SED) "s|_libexecdir_|@libexecdir@|g" 99-nfs.rules.in > $@

+

+clean-local:

+	$(RM) 99-nfs.rules

diff --git a/tools/nfsrahead/main.c b/tools/nfsrahead/main.c

new file mode 100644

index 00000000..c83c6f71

--- /dev/null

+++ b/tools/nfsrahead/main.c

@@ -0,0 +1,192 @@

+#include <stdio.h>

+#include <string.h>

+#include <stdlib.h>

+#include <errno.h>

+#include <unistd.h>

+

+#include <libmount/libmount.h>

+#include <sys/sysmacros.h>

+

+#include "xlog.h"

+#include "conffile.h"

+

+#ifndef MOUNTINFO_PATH

+#define MOUNTINFO_PATH "/proc/self/mountinfo"

+#endif

+

+#define CONF_NAME "nfsrahead"

+#define NFS_DEFAULT_READAHEAD 128

+

+/* Device information from the system */

+struct device_info {

+	char *device_number;

+	dev_t dev;

+	char *mountpoint;

+	char *fstype;

+};

+

+/* Convert a string in the format n:m to a device number */

+static int fill_device_number(struct device_info *info)

+{

+	char *s = strdup(info->device_number), *p;

+	char *maj_s, *min_s;

+	unsigned int maj, min;

+	int err = -EINVAL;

+

+	maj_s = p = s;

+	for ( ; *p != ':' && *p != '\0'; p++)

+		;

+

+	if (*p == '\0')

+		goto out_free;

+

+	err = 0;

+	*p = '\0';

+	min_s = p + 1;

+

+	maj = strtol(maj_s, NULL, 10);

+	min = strtol(min_s, NULL, 10);

+

+	info->dev = makedev(maj, min);

+out_free:

+	free(s);

+	return err;

+}

+

+#define sfree(ptr) if (ptr) free(ptr)

+

+/* device_info maintenance */

+static void init_device_info(struct device_info *di, const char *device_number)

+{

+	di->device_number = strdup(device_number);

+	di->dev = 0;

+	di->mountpoint = NULL;

+	di->fstype = NULL;

+}

+

+

+static void free_device_info(struct device_info *di)

+{

+	sfree(di->mountpoint);

+	sfree(di->fstype);

+	sfree(di->device_number);

+}

+

+static int get_mountinfo(const char *device_number, struct device_info *device_info, const char *mountinfo_path)

+{

+	int ret = 0;

+	struct libmnt_table *mnttbl;

+	struct libmnt_fs *fs;

+	char *target;

+

+	init_device_info(device_info, device_number);

+	if ((ret = fill_device_number(device_info)) < 0)

+		goto out_free_device_info;

+

+	mnttbl = mnt_new_table();

+

+	if ((ret = mnt_table_parse_file(mnttbl, mountinfo_path)) < 0) {

+		xlog(D_GENERAL, "Failed to parse %s\n", mountinfo_path);

+		goto out_free_tbl;

+	}

+

+	if ((fs = mnt_table_find_devno(mnttbl, device_info->dev, MNT_ITER_FORWARD)) == NULL) {

+		ret = ENOENT;

+		goto out_free_tbl;

+	}

+

+	if ((target = (char *)mnt_fs_get_target(fs)) == NULL) {

+		ret = ENOENT;

+		goto out_free_fs;

+	}

+

+	device_info->mountpoint = strdup(target);

+	target = (char *)mnt_fs_get_fstype(fs);

+	if (target)

+		device_info->fstype = strdup(target);

+

+out_free_fs:

+	mnt_free_fs(fs);

+out_free_tbl:

+	mnt_free_table(mnttbl);

+out_free_device_info:

+	free(device_info->device_number);

+	device_info->device_number = NULL;

+	return ret;

+}

+

+static int get_device_info(const char *device_number, struct device_info *device_info)

+{

+	int ret = ENOENT;

+	for (int retry_count = 0; retry_count < 10 && ret != 0; retry_count++)

+		ret = get_mountinfo(device_number, device_info, MOUNTINFO_PATH);

+

+	return ret;

+}

+

+static int conf_get_readahead(const char *kind) {

+	int readahead = 0;

+

+	if((readahead = conf_get_num(CONF_NAME, kind, -1)) == -1)

+		readahead = conf_get_num(CONF_NAME, "default", NFS_DEFAULT_READAHEAD);

+	

+	return readahead;

+}

+

+int main(int argc, char **argv)

+{

+	int ret = 0, retry, opt;

+	struct device_info device;

+	unsigned int readahead = 128, log_level, log_stderr = 0;

+

+

+	log_level = D_ALL & ~D_GENERAL;

+	while((opt = getopt(argc, argv, "dF")) != -1) {

+		switch (opt) {

+		case 'd':

+			log_level = D_ALL;

+			break;

+		case 'F':

+			log_stderr = 1;

+			break;

+		}

+	}

+

+	conf_init_file(NFS_CONFFILE);

+

+	xlog_stderr(log_stderr);

+	xlog_syslog(~log_stderr);

+	xlog_config(log_level, 1);

+	xlog_open(CONF_NAME);

+

+	// xlog_err causes the system to exit

+	if ((argc - optind) != 1)

+		xlog_err("expected the device number of a BDI; is udev ok?");

+

+	for (retry = 0; retry <= 10; retry++ )

+		if ((ret = get_device_info(argv[optind], &device)) == 0)

+			break;

+

+	if (ret != 0) {

+		xlog(D_GENERAL, "unable to find device %s\n", argv[optind]);

+		goto out;

+	}

+

+	if (strncmp("nfs", device.fstype, 3) != 0) {

+		xlog(D_GENERAL,

+			"not setting readahead for non supported fstype %s on device %s\n",

+			device.fstype, argv[optind]);

+		ret = -EINVAL;

+		goto out;

+	}

+

+	readahead = conf_get_readahead(device.fstype);

+

+	xlog(D_FAC7, "setting %s readahead to %d\n", device.mountpoint, readahead);

+

+	printf("%d\n", readahead);

+

+out:

+	free_device_info(&device);

+	return ret;

+}

diff --git a/tools/nfsrahead/nfsrahead.man b/tools/nfsrahead/nfsrahead.man

new file mode 100644

index 00000000..5488f633

--- /dev/null

+++ b/tools/nfsrahead/nfsrahead.man

@@ -0,0 +1,72 @@

+.\" Manpage for nfsrahead.

+.nh

+.ad l

+.TH man 5 "08 Mar 2022" "1.0" "nfsrahead man page"

+.SH NAME

+

+nfsrahead \- Configure the readahead for NFS mounts

+

+.SH SYNOPSIS

+

+nfsrahead [-F] [-d] <device>

+

+.SH DESCRIPTION

+

+\fInfsrahead\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 OPTIONS

+.TP

+.B -F

+Send messages to 

+.I stderr 

+instead of

+.I syslog

+

+.TP

+.B -d

+Increase the debugging level.

+

+.SH CONFIGURATION

+.I nfsrahead

+is configured in

+.IR /etc/nfs.conf ,

+in the section titled

+.IR nfsrahead .

+It accepts the following configurations.

+

+.TP

+.B nfs=<value>

+The readahead value applied to NFSv3 mounts.

+

+.TP

+.B nfs4=<value>

+The readahead value applied to NFSv4 mounts.

+

+.TP

+.B default=<value>

+The default configuration when none of the configurations above is set.

+

+.SH EXAMPLE CONFIGURATION

+[nfsrahead]

+.br

+nfs=15000              # readahead of 15000 for NFSv3 mounts

+.br

+nfs4=16000             # readahead of 16000 for NFSv4 mounts

+.br

+default=128            # default is 128

+

+.SH SEE ALSO

+

+.BR mount.nfs (8),

+.BR nfs (5),

+.BR nfs.conf (5),

+.BR udev (7),

+.BR bcc-readahead (8)

+

+.SH BUGS

+

+No known bugs.

+

+.SH AUTHOR

+

+Thiago Rafael Becker <trbecker@gmail.com>

diff --git a/utils/nfsidmap/nfsidmap.man b/utils/nfsidmap/nfsidmap.man

index 2af16f31..1911c41b 100644

--- a/utils/nfsidmap/nfsidmap.man

+++ b/utils/nfsidmap/nfsidmap.man

@@ -2,7 +2,7 @@

 .\"@(#)nfsidmap(8) - The NFS idmapper upcall program

 .\"

 .\" Copyright (C) 2010 Bryan Schumaker <bjschuma@netapp.com>

-.TH nfsidmap 5 "1 October 2010"

+.TH nfsidmap 8 "1 October 2010"

 .SH NAME

 nfsidmap \- The NFS idmapper upcall program

 .SH SYNOPSIS