2022-03-09 18:59:06

by Thiago Rafael Becker

Subject: [RFC PATCH 0/7] Introduce nfs-readahead-udev

This patch series introduces nfs-readahead-udev, a utility to
automatically set NFS readahead when a mountpoint is mounted.

The tool currently supports setting read ahead per mountpoint, nfs major
version, or by a global default value.

Thiago Rafael Becker (7):
Create nfs-readahead-udev
readahead: configure udev
readahead: create logging facility
readahead: only set readahead for nfs devices.
readahead: create the configuration file
readahead: add mountpoint and fstype options
readahead: documentation

.gitignore | 6 +
configure.ac | 4 +
tools/Makefile.am | 2 +-
tools/nfs-readahead-udev/99-nfs_bdi.rules.in | 1 +
tools/nfs-readahead-udev/Makefile.am | 26 +++
tools/nfs-readahead-udev/config_parser.c | 25 +++
tools/nfs-readahead-udev/config_parser.h | 14 ++
tools/nfs-readahead-udev/list.h | 48 ++++
tools/nfs-readahead-udev/log.h | 16 ++
tools/nfs-readahead-udev/main.c | 211 ++++++++++++++++++
.../nfs-readahead-udev/nfs-readahead-udev.man | 47 ++++
tools/nfs-readahead-udev/parser.y | 85 +++++++
tools/nfs-readahead-udev/readahead.conf | 15 ++
tools/nfs-readahead-udev/scanner.l | 19 ++
tools/nfs-readahead-udev/syslog.c | 47 ++++
15 files changed, 565 insertions(+), 1 deletion(-)
create mode 100644 tools/nfs-readahead-udev/99-nfs_bdi.rules.in
create mode 100644 tools/nfs-readahead-udev/Makefile.am
create mode 100644 tools/nfs-readahead-udev/config_parser.c
create mode 100644 tools/nfs-readahead-udev/config_parser.h
create mode 100644 tools/nfs-readahead-udev/list.h
create mode 100644 tools/nfs-readahead-udev/log.h
create mode 100644 tools/nfs-readahead-udev/main.c
create mode 100644 tools/nfs-readahead-udev/nfs-readahead-udev.man
create mode 100644 tools/nfs-readahead-udev/parser.y
create mode 100644 tools/nfs-readahead-udev/readahead.conf
create mode 100644 tools/nfs-readahead-udev/scanner.l
create mode 100644 tools/nfs-readahead-udev/syslog.c

--
2.35.1

2022-03-09 19:19:15

by Thiago Rafael Becker

Subject: [RFC PATCH 4/7] readahead: only set readahead for nfs devices.

Limit setting the readahead for nfs devices.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <[email protected]>
---
tools/nfs-readahead-udev/99-nfs_bdi.rules.in | 2 +-
tools/nfs-readahead-udev/Makefile.am | 1 +
tools/nfs-readahead-udev/main.c | 132 ++++++++++++++++++-
3 files changed, 133 insertions(+), 2 deletions(-)

diff --git a/tools/nfs-readahead-udev/99-nfs_bdi.rules.in b/tools/nfs-readahead-udev/99-nfs_bdi.rules.in
index 15f8a995..744c59be 100644
--- a/tools/nfs-readahead-udev/99-nfs_bdi.rules.in
+++ b/tools/nfs-readahead-udev/99-nfs_bdi.rules.in
@@ -1 +1 @@
-SUBSYSTEM=="bdi", ACTION=="add", PROGRAM="_libexecdir_/nfs-readahead-udev", ATTR{read_ahead_kb}="%c"
+SUBSYSTEM=="bdi", ACTION=="add", PROGRAM="_libexecdir_/nfs-readahead-udev %k", ATTR{read_ahead_kb}="%c"
diff --git a/tools/nfs-readahead-udev/Makefile.am b/tools/nfs-readahead-udev/Makefile.am
index 5078db9a..551d22e9 100644
--- a/tools/nfs-readahead-udev/Makefile.am
+++ b/tools/nfs-readahead-udev/Makefile.am
@@ -1,5 +1,6 @@
libexec_PROGRAMS = nfs-readahead-udev
nfs_readahead_udev_SOURCES = main.c syslog.c
+nfs_readahead_udev_LDFLAGS= -lmount

udev_rulesdir = /etc/udev/rules.d
udev_rules_DATA = 99-nfs_bdi.rules
diff --git a/tools/nfs-readahead-udev/main.c b/tools/nfs-readahead-udev/main.c
index dd2c9f8c..bbb408c0 100644
--- a/tools/nfs-readahead-udev/main.c
+++ b/tools/nfs-readahead-udev/main.c
@@ -1,15 +1,145 @@
#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#include <libmount/libmount.h>
+#include <sys/sysmacros.h>

#include "log.h"

+#ifndef MOUNTINFO_PATH
+#define MOUNTINFO_PATH "/proc/self/mountinfo"
+#endif
+
+/* 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 dev_t dev_from_arg(const char *device_number)
+{
+ char *s = strdup(device_number), *p;
+ char *maj_s, *min_s;
+ unsigned int maj, min;
+ dev_t dev;
+
+ maj_s = p = s;
+ for ( ; *p != ':'; p++)
+ ;
+
+ *p = '\0';
+ min_s = p + 1;
+
+ maj = strtol(maj_s, NULL, 10);
+ min = strtol(min_s, NULL, 10);
+
+ dev = makedev(maj, min);
+
+ free(s);
+ return dev;
+}
+
+#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 = dev_from_arg(device_number);
+ 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);
+
+ mnttbl = mnt_new_table();
+
+ if ((ret = mnt_table_parse_file(mnttbl, mountinfo_path)) < 0)
+ 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);
+ 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;
+}
+
int main(int argc, char **argv, char **envp)
{
+ int ret = 0;
+ struct device_info device;
unsigned int readahead = 128;

log_open();

- info("Setting the readahead to 128\n");
+ if (argc != 2) {
+ err("Expected device number as argument, got none\n");
+ return -EINVAL;
+ }
+
+ if ((ret = get_device_info(argv[1], &device)) != 0) {
+ err("Failed to find device %s (%d)\n", argv[1], ret);
+ goto out;
+ }
+
+ if (strncmp("nfs", device.fstype, 3) != 0) {
+ ret = -EINVAL;
+ info("Not setting the readahead for fstype %s\n", device.fstype);
+ goto out;
+ }
+
+ info("Setting %s readahead to 128\n", device.mountpoint);

log_close();
printf("%d\n", readahead);
+
+out:
+ free_device_info(&device);
+ return ret;
}
--
2.35.1

2022-03-09 20:06:24

by Thiago Rafael Becker

Subject: [RFC PATCH 1/7] Create nfs-readahead-udev

This tool is invoked by udev to find and set the readahead value to NFS
mounts.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <[email protected]>
---
.gitignore | 1 +
configure.ac | 1 +
tools/Makefile.am | 2 +-
tools/nfs-readahead-udev/Makefile.am | 3 +++
tools/nfs-readahead-udev/main.c | 7 +++++++
5 files changed, 13 insertions(+), 1 deletion(-)
create mode 100644 tools/nfs-readahead-udev/Makefile.am
create mode 100644 tools/nfs-readahead-udev/main.c

diff --git a/.gitignore b/.gitignore
index c89d1cd2..c99269a4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -61,6 +61,7 @@ utils/statd/statd
tools/locktest/testlk
tools/getiversion/getiversion
tools/nfsconf/nfsconf
+tools/nfs-readahead-udev/nfs-readahead-udev
support/export/mount.h
support/export/mount_clnt.c
support/export/mount_xdr.c
diff --git a/configure.ac b/configure.ac
index e0f5a930..7e5ba5d9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -737,6 +737,7 @@ AC_CONFIG_FILES([
tools/rpcgen/Makefile
tools/mountstats/Makefile
tools/nfs-iostat/Makefile
+ tools/nfs-readahead-udev/Makefile
tools/rpcctl/Makefile
tools/nfsdclnts/Makefile
tools/nfsconf/Makefile
diff --git a/tools/Makefile.am b/tools/Makefile.am
index c3feabbe..621cde03 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 nfs-readahead-udev $(OPTDIRS)

MAINTAINERCLEANFILES = Makefile.in
diff --git a/tools/nfs-readahead-udev/Makefile.am b/tools/nfs-readahead-udev/Makefile.am
new file mode 100644
index 00000000..5455e954
--- /dev/null
+++ b/tools/nfs-readahead-udev/Makefile.am
@@ -0,0 +1,3 @@
+libexec_PROGRAMS = nfs-readahead-udev
+nfs_readahead_udev_SOURCES = main.c
+
diff --git a/tools/nfs-readahead-udev/main.c b/tools/nfs-readahead-udev/main.c
new file mode 100644
index 00000000..e454108e
--- /dev/null
+++ b/tools/nfs-readahead-udev/main.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main(int argc, char **argv, char **envp)
+{
+ unsigned int readahead = 128;
+ printf("%d\n", readahead);
+}
--
2.35.1

2022-03-10 00:06:31

by Thiago Rafael Becker

Subject: [RFC PATCH 7/7] readahead: documentation

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <[email protected]>
---
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 <[email protected]>
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

2022-03-10 09:08:13

by Thiago Rafael Becker

Subject: [RFC PATCH 3/7] readahead: create logging facility

Create logs for nfs-readahead-udev, logging to syslog.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <[email protected]>
---
tools/nfs-readahead-udev/Makefile.am | 2 +-
tools/nfs-readahead-udev/log.h | 16 ++++++++++
tools/nfs-readahead-udev/main.c | 8 +++++
tools/nfs-readahead-udev/syslog.c | 47 ++++++++++++++++++++++++++++
4 files changed, 72 insertions(+), 1 deletion(-)
create mode 100644 tools/nfs-readahead-udev/log.h
create mode 100644 tools/nfs-readahead-udev/syslog.c

diff --git a/tools/nfs-readahead-udev/Makefile.am b/tools/nfs-readahead-udev/Makefile.am
index 873cc175..5078db9a 100644
--- a/tools/nfs-readahead-udev/Makefile.am
+++ b/tools/nfs-readahead-udev/Makefile.am
@@ -1,5 +1,5 @@
libexec_PROGRAMS = nfs-readahead-udev
-nfs_readahead_udev_SOURCES = main.c
+nfs_readahead_udev_SOURCES = main.c syslog.c

udev_rulesdir = /etc/udev/rules.d
udev_rules_DATA = 99-nfs_bdi.rules
diff --git a/tools/nfs-readahead-udev/log.h b/tools/nfs-readahead-udev/log.h
new file mode 100644
index 00000000..2a14e552
--- /dev/null
+++ b/tools/nfs-readahead-udev/log.h
@@ -0,0 +1,16 @@
+#ifndef __ra_log_h__
+#define __ra_log_h__
+#include <stdarg.h>
+
+extern void log_open(void);
+extern void log_close(void);
+
+extern void debug(const char *, ...);
+extern void info(const char *, ...);
+extern void notice(const char *, ...);
+extern void warn(const char *, ...);
+extern void err(const char *, ...);
+extern void crit(const char *, ...);
+extern void alert(const char *, ...);
+extern void emerg(const char *, ...);
+#endif
diff --git a/tools/nfs-readahead-udev/main.c b/tools/nfs-readahead-udev/main.c
index e454108e..dd2c9f8c 100644
--- a/tools/nfs-readahead-udev/main.c
+++ b/tools/nfs-readahead-udev/main.c
@@ -1,7 +1,15 @@
#include <stdio.h>

+#include "log.h"
+
int main(int argc, char **argv, char **envp)
{
unsigned int readahead = 128;
+
+ log_open();
+
+ info("Setting the readahead to 128\n");
+
+ log_close();
printf("%d\n", readahead);
}
diff --git a/tools/nfs-readahead-udev/syslog.c b/tools/nfs-readahead-udev/syslog.c
new file mode 100644
index 00000000..5eeb2579
--- /dev/null
+++ b/tools/nfs-readahead-udev/syslog.c
@@ -0,0 +1,47 @@
+#include <syslog.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "log.h"
+
+#define MSG_SIZE (1024 * sizeof(char))
+
+void log_open(void)
+{
+ openlog("nfs_readahead", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);
+ setlogmask(LOG_UPTO(LOG_DEBUG));
+}
+
+void log_close(void)
+{
+ closelog();
+}
+
+static void vlog(int level, const char *fmt, va_list *args)
+{
+ char *msg = malloc(MSG_SIZE);
+ if (!msg)
+ return;
+
+ vsnprintf(msg, MSG_SIZE, fmt, *args);
+ syslog(level, "%s", msg);
+
+ free(msg);
+}
+
+#define GENERATE_LOGGER(name, level) \
+ void name(const char *fmt, ...) { \
+ va_list args; \
+ va_start(args, fmt); \
+ vlog(LOG_##level, fmt, &args); \
+ va_end(args); \
+}
+
+GENERATE_LOGGER(debug, DEBUG);
+GENERATE_LOGGER(info, INFO);
+GENERATE_LOGGER(notice, NOTICE);
+GENERATE_LOGGER(warn, WARNING);
+GENERATE_LOGGER(err, ERR);
+GENERATE_LOGGER(crit, CRIT);
+GENERATE_LOGGER(alert, ALERT);
+GENERATE_LOGGER(emerg, EMERG);
--
2.35.1

2022-03-10 09:27:06

by Thiago Rafael Becker

Subject: [RFC PATCH 2/7] readahead: configure udev

Set the udev rule to call the readahead utility.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <[email protected]>
---
tools/nfs-readahead-udev/99-nfs_bdi.rules.in | 1 +
tools/nfs-readahead-udev/Makefile.am | 8 ++++++++
2 files changed, 9 insertions(+)
create mode 100644 tools/nfs-readahead-udev/99-nfs_bdi.rules.in

diff --git a/tools/nfs-readahead-udev/99-nfs_bdi.rules.in b/tools/nfs-readahead-udev/99-nfs_bdi.rules.in
new file mode 100644
index 00000000..15f8a995
--- /dev/null
+++ b/tools/nfs-readahead-udev/99-nfs_bdi.rules.in
@@ -0,0 +1 @@
+SUBSYSTEM=="bdi", ACTION=="add", PROGRAM="_libexecdir_/nfs-readahead-udev", ATTR{read_ahead_kb}="%c"
diff --git a/tools/nfs-readahead-udev/Makefile.am b/tools/nfs-readahead-udev/Makefile.am
index 5455e954..873cc175 100644
--- a/tools/nfs-readahead-udev/Makefile.am
+++ b/tools/nfs-readahead-udev/Makefile.am
@@ -1,3 +1,11 @@
libexec_PROGRAMS = nfs-readahead-udev
nfs_readahead_udev_SOURCES = main.c

+udev_rulesdir = /etc/udev/rules.d
+udev_rules_DATA = 99-nfs_bdi.rules
+
+99-nfs_bdi.rules: 99-nfs_bdi.rules.in $(builddefs)
+ $(SED) "s|_libexecdir_|@libexecdir@|g" 99-nfs_bdi.rules.in > $@
+
+clean-local:
+ $(RM) 99-nfs_bdi.rules
--
2.35.1

2022-03-10 10:08:42

by Thiago Rafael Becker

Subject: [RFC PATCH 5/7] readahead: create the configuration file

At this stage, the configuration file only accepts the default value.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283
Signed-off-by: Thiago Rafael Becker <[email protected]>
---
.gitignore | 5 ++
configure.ac | 3 +
tools/nfs-readahead-udev/Makefile.am | 16 ++++-
tools/nfs-readahead-udev/config_parser.c | 25 ++++++++
tools/nfs-readahead-udev/config_parser.h | 14 +++++
tools/nfs-readahead-udev/list.h | 48 +++++++++++++++
tools/nfs-readahead-udev/main.c | 68 ++++++++++++++++++++-
tools/nfs-readahead-udev/parser.y | 78 ++++++++++++++++++++++++
tools/nfs-readahead-udev/readahead.conf | 1 +
tools/nfs-readahead-udev/scanner.l | 14 +++++
10 files changed, 269 insertions(+), 3 deletions(-)
create mode 100644 tools/nfs-readahead-udev/config_parser.c
create mode 100644 tools/nfs-readahead-udev/config_parser.h
create mode 100644 tools/nfs-readahead-udev/list.h
create mode 100644 tools/nfs-readahead-udev/parser.y
create mode 100644 tools/nfs-readahead-udev/readahead.conf
create mode 100644 tools/nfs-readahead-udev/scanner.l

diff --git a/.gitignore b/.gitignore
index c99269a4..340ee8fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,7 @@ aclocal/ltoptions.m4
aclocal/ltsugar.m4
aclocal/ltversion.m4
aclocal/lt~obsolete.m4
+ylwrap
# files generated by configure
confdefs.h
config.cache
@@ -61,7 +62,11 @@ utils/statd/statd
tools/locktest/testlk
tools/getiversion/getiversion
tools/nfsconf/nfsconf
+tools/nfs-readahead-udev/99-nfs_bdi.rules
tools/nfs-readahead-udev/nfs-readahead-udev
+tools/nfs-readahead-udev/parser.c
+tools/nfs-readahead-udev/parser.h
+tools/nfs-readahead-udev/scanner.c
support/export/mount.h
support/export/mount_clnt.c
support/export/mount_xdr.c
diff --git a/configure.ac b/configure.ac
index 7e5ba5d9..03cdf8f6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -300,7 +300,10 @@ AC_PROG_INSTALL
AC_PROG_LN_S
AC_PROG_MAKE_SET
AC_PROG_LIBTOOL
+AC_PROG_YACC
AM_PROG_CC_C_O
+AM_PROG_LEX
+

if test "x$cross_compiling" = "xno"; then
CC_FOR_BUILD=${CC_FOR_BUILD-${CC-gcc}}
diff --git a/tools/nfs-readahead-udev/Makefile.am b/tools/nfs-readahead-udev/Makefile.am
index 551d22e9..010350aa 100644
--- a/tools/nfs-readahead-udev/Makefile.am
+++ b/tools/nfs-readahead-udev/Makefile.am
@@ -1,12 +1,24 @@
libexec_PROGRAMS = nfs-readahead-udev
-nfs_readahead_udev_SOURCES = main.c syslog.c
+BUILT_SOURCES = parser.c parser.h scanner.c
+nfs_readahead_udev_SOURCES = main.c syslog.c config_parser.c parser.y scanner.l
nfs_readahead_udev_LDFLAGS= -lmount
+AM_YFLAGS = -d

-udev_rulesdir = /etc/udev/rules.d
+udev_rulesdir = $(sysconfdir)/udev/rules.d
udev_rules_DATA = 99-nfs_bdi.rules

+ra_confdir = $(sysconfdir)
+ra_conf_DATA = readahead.conf
+
99-nfs_bdi.rules: 99-nfs_bdi.rules.in $(builddefs)
$(SED) "s|_libexecdir_|@libexecdir@|g" 99-nfs_bdi.rules.in > $@

clean-local:
$(RM) 99-nfs_bdi.rules
+ $(RM) parser.c parser.h scanner.c
+
+parser.$(OBJEXT): CFLAGS += -Wno-strict-prototypes
+
+scanner.$(OBJEXT): CFLAGS += -Wno-strict-prototypes
+
+main.$(OBJEXT): CFLAGS += -DSYSCONFDIR=\"@sysconfdir@\"
diff --git a/tools/nfs-readahead-udev/config_parser.c b/tools/nfs-readahead-udev/config_parser.c
new file mode 100644
index 00000000..24d58a6b
--- /dev/null
+++ b/tools/nfs-readahead-udev/config_parser.c
@@ -0,0 +1,25 @@
+#include <stdlib.h>
+#include <string.h>
+#include "config_parser.h"
+
+struct config_entry *config_entry_new(void);
+
+struct config_entry *config_entry_new(void) {
+ struct config_entry *new = malloc(sizeof(struct config_entry));
+ if (!new) {
+ return NULL; // Make this an err_ptr
+ }
+
+ memset(new, 0, sizeof(struct config_entry));
+ list_init(&new->list);
+ return new;
+}
+
+
+void config_entry_free(struct config_entry *ce)
+{
+#define sfree(ce) if (ce) free(ce)
+ sfree(ce->mountpoint);
+ sfree(ce->fstype);
+#undef sfree
+}
diff --git a/tools/nfs-readahead-udev/config_parser.h b/tools/nfs-readahead-udev/config_parser.h
new file mode 100644
index 00000000..f9f138bb
--- /dev/null
+++ b/tools/nfs-readahead-udev/config_parser.h
@@ -0,0 +1,14 @@
+#ifndef __ra_libparser_h__
+#define __ra_libparser_h__
+#include "list.h"
+
+struct config_entry {
+ struct list_head list;
+ char *mountpoint;
+ char *fstype;
+ int readahead;
+};
+
+extern int parse_config(const char *, struct list_head *config_list);
+extern void config_entry_free(struct config_entry *);
+#endif
diff --git a/tools/nfs-readahead-udev/list.h b/tools/nfs-readahead-udev/list.h
new file mode 100644
index 00000000..69239502
--- /dev/null
+++ b/tools/nfs-readahead-udev/list.h
@@ -0,0 +1,48 @@
+#ifndef __ra_list_h__
+#define __ra_list_h__
+struct list_head
+{
+ struct list_head *next, *prev;
+};
+
+static inline void list_init(struct list_head *lh)
+{
+ lh->next = lh;
+ lh->prev = lh;
+}
+
+#define LIST_DECLARE(name) \
+ struct list_head name; \
+ list_init(&name);
+
+static inline void list_add(struct list_head *l, struct list_head *a)
+{
+ a->prev = l;
+ a->next = l->next;
+ l->next->prev = a;
+ l->next = a;
+}
+
+static inline void list_del(struct list_head *a)
+{
+ a->next->prev = a->prev;
+ a->prev->next = a->next;
+ a->next = a;
+ a->prev = a;
+}
+
+#define list_for_each(pos, head) \
+ for (pos = (head)->next; pos != (head); pos = pos->next)
+
+#define list_free(head, free_func) ({ \
+ for (struct list_head *__lh = (head)->next; \
+ __lh != head; __lh = (head)->next) { \
+ list_del(__lh); \
+ free_func(__lh); \
+ }})
+
+#define containerof(p, type, field) ({ \
+ const __typeof__(((type *)0)->field) *__ptr = (p); \
+ (type *)((char *)__ptr - offsetof(type, field) ); })
+
+#endif
diff --git a/tools/nfs-readahead-udev/main.c b/tools/nfs-readahead-udev/main.c
index bbb408c0..2bd76138 100644
--- a/tools/nfs-readahead-udev/main.c
+++ b/tools/nfs-readahead-udev/main.c
@@ -2,16 +2,23 @@
#include <string.h>
#include <stdlib.h>
#include <errno.h>
+#include <stddef.h>

#include <libmount/libmount.h>
#include <sys/sysmacros.h>

#include "log.h"
+#include "list.h"
+#include "config_parser.h"

#ifndef MOUNTINFO_PATH
#define MOUNTINFO_PATH "/proc/self/mountinfo"
#endif

+#ifndef READAHEAD_CONFIG_FILE
+#define READAHEAD_CONFIG_FILE SYSCONFDIR "/readahead.conf"
+#endif
+
/* Device information from the system */
struct device_info {
char *device_number;
@@ -110,6 +117,60 @@ static int get_device_info(const char *device_number, struct device_info *device
return ret;
}

+static void config_entry_list_head_free(struct list_head *lh) {
+ struct config_entry *ce = containerof(lh, struct config_entry, list);
+ config_entry_free(ce);
+}
+
+static int match_config(struct device_info *di, struct config_entry *ce) {
+#define FIELD_CMP(field) \
+ (ce->field == NULL || (di->field != NULL && strcmp(di->field, ce->field) == 0))
+
+ if (!FIELD_CMP(mountpoint))
+ return 0;
+
+ if (!FIELD_CMP(fstype))
+ return 0;
+
+ debug("Device matched with config\n");
+ return 1;
+#undef FIELD_CMP
+}
+
+static int get_readahead(struct device_info *di, unsigned int *readahead)
+{
+ LIST_DECLARE(configs);
+ struct list_head *lh;
+ int ret = 0;
+ int default_ra = 0;
+
+ if ((ret = parse_config(READAHEAD_CONFIG_FILE, &configs)) != 0) {
+ err("Failed to read configuration (%d)\n", ret);
+ goto out;
+ }
+
+ list_for_each(lh, &configs) {
+ struct config_entry *ce = containerof(lh, struct config_entry, list);
+ if (ce->mountpoint == NULL && ce->fstype == NULL) {
+ default_ra = ce->readahead;
+ continue;
+ }
+
+ if (match_config(di, ce)) {
+ *readahead = ce->readahead;
+ goto out;
+ }
+ }
+
+ /* fallthrough */
+ debug("Setting readahead to default %d\n", default_ra);
+ *readahead = default_ra;
+
+out:
+ list_free(&configs, config_entry_list_head_free);
+ return ret;
+}
+
int main(int argc, char **argv, char **envp)
{
int ret = 0;
@@ -134,7 +195,12 @@ int main(int argc, char **argv, char **envp)
goto out;
}

- info("Setting %s readahead to 128\n", device.mountpoint);
+ if ((ret = get_readahead(&device, &readahead)) != 0) {
+ err("Failed to find readahead (%d)\n", ret);
+ goto out;
+ }
+
+ info("Setting %s readahead to %u\n", device.mountpoint, readahead);

log_close();
printf("%d\n", readahead);
diff --git a/tools/nfs-readahead-udev/parser.y b/tools/nfs-readahead-udev/parser.y
new file mode 100644
index 00000000..f6db05c4
--- /dev/null
+++ b/tools/nfs-readahead-udev/parser.y
@@ -0,0 +1,78 @@
+%{
+#include <stdio.h>
+#include "parser.h"
+#include "config_parser.h"
+#include "log.h"
+
+extern int yylex();
+extern int yyparse();
+extern FILE *yyin;
+void yyerror(const char *s);
+
+// This should be visible only to this file
+extern struct config_entry *config_entry_new(void);
+
+struct config_entry *current;
+%}
+
+%union {
+ int ival;
+}
+
+%token <ival> INT
+%token EQ
+%token ENDL
+%token DEFAULT
+%token READAHEAD
+%token END_CONFIG 0
+
+%%
+config:
+ lines
+lines:
+ lines line | line | endls lines
+line:
+ tokens endls {
+ struct config_entry *new = config_entry_new();
+ list_add(&current->list, &new->list);
+ current = new;
+ }
+
+
+tokens:
+ tokens token | token
+
+token:
+ default | pair
+
+default:
+ DEFAULT
+
+pair:
+ READAHEAD EQ INT { current->readahead = $3; }
+
+endls:
+ endls ENDL | ENDL
+
+%%
+int parse_config(const char *filename, struct list_head *list)
+{
+ int ret;
+
+ yyin = fopen(filename, "r");
+ current = config_entry_new();
+ list_add(list, &current->list);
+
+ ret = yyparse();
+
+ /* The parser will create an empty entry that need to be eliminated */
+ list_del(&current->list);
+ free(current);
+ fclose(yyin);
+
+ return ret;
+}
+
+void yyerror(const char *s) {
+ err("Failed to parse configuration: %s", s);
+}
diff --git a/tools/nfs-readahead-udev/readahead.conf b/tools/nfs-readahead-udev/readahead.conf
new file mode 100644
index 00000000..988b30c7
--- /dev/null
+++ b/tools/nfs-readahead-udev/readahead.conf
@@ -0,0 +1 @@
+default readahead=128
diff --git a/tools/nfs-readahead-udev/scanner.l b/tools/nfs-readahead-udev/scanner.l
new file mode 100644
index 00000000..d1ceb90b
--- /dev/null
+++ b/tools/nfs-readahead-udev/scanner.l
@@ -0,0 +1,14 @@
+%{
+#include "parser.h"
+#define yyterminate() return END_CONFIG
+%}
+%option noyywrap
+%%
+default { return DEFAULT; }
+readahead { return READAHEAD; }
+[ \t] ;
+#[^\n]*\n { return ENDL; }
+\n { return ENDL; }
+[0-9]+ { yylval.ival = atoi(yytext); return INT; }
+= { return EQ; }
+%%
--
2.35.1

2022-03-10 10:31:35

by Chuck Lever III

Subject: Re: [RFC PATCH 0/7] Introduce nfs-readahead-udev

> On Mar 9, 2022, at 1:26 PM, Thiago Rafael Becker <[email protected]> wrote:
>
> This patch series introduces nfs-readahead-udev, a utility to
> automatically set NFS readahead when a mountpoint is mounted.
>
> The tool currently supports setting read ahead per mountpoint, nfs major
> version, or by a global default value.

Hi Thiago --

Your cover letter explains "what", but it should also
explain "why". I don't recall seeing previous discussion
of an issue in this area, but then, my memory isn't what
it used to be. If there is a previous thread (or threads)
please provide some links to the threads on lore.kernel.org
in your cover letter.

Good "why" information includes:

Do you, for example, have some performance results that
demonstrate a problem and some improvement? Are there
one or two specific use cases for adjusting NFS readahead?
What are the requirements for doing this via udev versus
via some other mechanism?

Having that kind of information helps us review your
patches.

Also, since this is a client-side tool (IIUC) please Cc:
Trond and Anna. You don't have to Cc: me, since I'm a
Linux NFS server maintainer.

And also: I'm not sure what Red Hat's contributor
policy is, but do you need "Signed-off-by: Thiago
Rafael Becker <[email protected]?" instead of your
gmail address? Just making sure all the legal p's
and q's are dotted and crossed.


> Thiago Rafael Becker (7):
> Create nfs-readahead-udev
> readahead: configure udev
> readahead: create logging facility
> readahead: only set readahead for nfs devices.
> readahead: create the configuration file
> readahead: add mountpoint and fstype options
> readahead: documentation
>
> .gitignore | 6 +
> configure.ac | 4 +
> tools/Makefile.am | 2 +-
> tools/nfs-readahead-udev/99-nfs_bdi.rules.in | 1 +
> tools/nfs-readahead-udev/Makefile.am | 26 +++
> tools/nfs-readahead-udev/config_parser.c | 25 +++
> tools/nfs-readahead-udev/config_parser.h | 14 ++
> tools/nfs-readahead-udev/list.h | 48 ++++
> tools/nfs-readahead-udev/log.h | 16 ++
> tools/nfs-readahead-udev/main.c | 211 ++++++++++++++++++
> .../nfs-readahead-udev/nfs-readahead-udev.man | 47 ++++
> tools/nfs-readahead-udev/parser.y | 85 +++++++
> tools/nfs-readahead-udev/readahead.conf | 15 ++
> tools/nfs-readahead-udev/scanner.l | 19 ++
> tools/nfs-readahead-udev/syslog.c | 47 ++++
> 15 files changed, 565 insertions(+), 1 deletion(-)
> create mode 100644 tools/nfs-readahead-udev/99-nfs_bdi.rules.in
> create mode 100644 tools/nfs-readahead-udev/Makefile.am
> create mode 100644 tools/nfs-readahead-udev/config_parser.c
> create mode 100644 tools/nfs-readahead-udev/config_parser.h
> create mode 100644 tools/nfs-readahead-udev/list.h
> create mode 100644 tools/nfs-readahead-udev/log.h
> create mode 100644 tools/nfs-readahead-udev/main.c
> create mode 100644 tools/nfs-readahead-udev/nfs-readahead-udev.man
> create mode 100644 tools/nfs-readahead-udev/parser.y
> create mode 100644 tools/nfs-readahead-udev/readahead.conf
> create mode 100644 tools/nfs-readahead-udev/scanner.l
> create mode 100644 tools/nfs-readahead-udev/syslog.c
>
> --
> 2.35.1
>

--
Chuck Lever