Attachment 922917 Details for Bug 1125273 – C program to register a bcache device, trying again when appropriate

C program to register a bcache device, trying again when appropriate

bcreg.c (text/plain), 1.63 KB, created by Ian Pilcher on 2014-07-31 13:20:50 UTC

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Creator: Ian Pilcher

Created: 2014-07-31 13:20:50 UTC

Size: 1.63 KB

patch

obsolete

>#include <stdlib.h>
>#include <string.h>
>#include <unistd.h>
>#include <stdio.h>
>#include <fcntl.h>
>#include <errno.h>
>#include <time.h>
>
>/* How often to wake up and check when waiting for something; 1/10 second */
>#define WAKEUP_NSEC		100000000L
>
>/* Timeouts are in multiples of WAKEUP_NSEC */
>#define SYSFS_TIMEOUT		50	/* 5 seconds */
>#define DEVICE_TIMEOUT		50	/* 5 seconds */
>
>static const char sysfs_reg[] = "/sys/fs/bcache/register";
>
>int main(int argc, char *argv[])
>{
>	struct timespec timeout;
>	size_t len;
>	int i, fd;
>
>	if (argc != 2) {
>		fprintf(stderr, "USAGE: %s <BLOCK_DEVICE>\n", argv[0]);
>		exit(EXIT_FAILURE);
>	}
>
>	i = SYSFS_TIMEOUT;
>
>	while (1) {
>
>		fd = open(sysfs_reg, O_WRONLY);
>		if (fd != -1)
>			break;
>
>		if (errno != ENOENT) {
>			perror(sysfs_reg);
>			exit(EXIT_FAILURE);
>		}
>
>		if (i-- == 0) {
>			fprintf(stderr, "Timed out waiting for %s\n", sysfs_reg);
>			exit(EXIT_FAILURE);
>		}
>
>		timeout.tv_sec = 0;
>		timeout.tv_nsec = WAKEUP_NSEC;
>
>		if (nanosleep(&timeout, NULL) == -1) {
>			perror("nanosleep");
>			exit(EXIT_FAILURE);
>		}
>	}
>
>	len = strlen(argv[1]);
>	i = DEVICE_TIMEOUT;
>
>	while (1) {
>
>		if (lseek(fd, 0, SEEK_SET) == -1) {
>			perror(sysfs_reg);
>			close(fd);
>			exit(EXIT_FAILURE);
>		}
>
>		if (write(fd, argv[1], len) == (ssize_t)len)
>			break;
>
>		if (errno != EBUSY) {
>			perror(argv[1]);
>			close(fd);
>			exit(EXIT_FAILURE);
>		}
>
>		if (i-- == 0) {
>			fprintf(stderr, "Timed out waiting for %s\n", argv[1]);
>			close(fd);
>			exit(EXIT_FAILURE);
>		}
>
>		timeout.tv_sec = 0;
>		timeout.tv_nsec = WAKEUP_NSEC;
>
>		if (nanosleep(&timeout, NULL) == -1) {
>			perror("nanosleep");
>			close(fd);
>			exit(EXIT_FAILURE);
>		}
>	}
>
>	close(fd);
>	return 0;
>}

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Attachments on bug 1125273: 922915 | 922917 | 922929