@@ -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"
@@ -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
@@ -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;
}
Limit setting the readahead for nfs devices. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1946283 Signed-off-by: Thiago Rafael Becker <trbecker@gmail.com> --- 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(-)