diff options
Diffstat (limited to 'tools/nfsrahead/main.c')
| -rw-r--r-- | tools/nfsrahead/main.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/tools/nfsrahead/main.c b/tools/nfsrahead/main.c new file mode 100644 index 0000000..8a11cf1 --- /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 || device.fstype == NULL) { + 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; +} |