Commit 890b657e authored by John Levon's avatar John Levon Committed by Tomasz Zawadzki
Browse files

examples: detect fio backend fd redirection 



It's useful to be able to run fio daemonized, and very recent versions of fio
redirect stdout/stderr to /dev/null in order to avoid the problem that
previously caused the plugin to abort. Detect if this redirection has happened
and allow fio to run in this case.

Signed-off-by: default avatarJohn Levon <john.levon@nutanix.com>
Change-Id: I8ec13a4c26a0acc67b15fa5e8502dc28d341e441
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/9691


Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarTomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: default avatarAndreas Economides <andreas.economides@nutanix.com>
parent 67519098

examples/bdev/fio_plugin/fio_plugin.c

+30 −7
Original line number Diff line number Diff line
@@ -426,6 +426,27 @@ out: 
	return rc;

}



static bool

fio_redirected_to_dev_null(void)

{

	char path[PATH_MAX] = "";

	ssize_t ret;



	ret = readlink("/proc/self/fd/1", path, sizeof(path));



	if (ret == -1 || strcmp(path, "/dev/null") != 0) {

		return false;

	}



	ret = readlink("/proc/self/fd/2", path, sizeof(path));



	if (ret == -1 || strcmp(path, "/dev/null") != 0) {

		return false;

	}



	return true;

}



/* Called for each thread to fill in the 'real_file_size' member for

 * each file associated with this thread. This is called prior to

 * the init operation (spdk_fio_init()) below. This call will occur
@@ -439,16 +460,18 @@ spdk_fio_setup(struct thread_data *td) 
	unsigned int i;

	struct fio_file *f;



	/* we might be running in a daemonized FIO instance where standard

	 * input and output were closed and fds 0, 1, and 2 are reused

	 * for something important by FIO. We can't ensure we won't print

	 * anything (and so will our dependencies, e.g. DPDK), so abort early.

	 * (is_backend is an fio global variable)

	/*

	 * If we're running in a daemonized FIO instance, it's possible

	 * fd 1/2 were re-used for something important by FIO. Newer fio

	 * versions are careful to redirect those to /dev/null, but if we're

	 * not, we'll abort early, so we don't accidentally write messages to

	 * an important file, etc.

	 */

	if (is_backend) {

	if (is_backend && !fio_redirected_to_dev_null()) {

		char buf[1024];

		snprintf(buf, sizeof(buf),

			 "SPDK FIO plugin won't work with daemonized FIO server.");

			 "SPDK FIO plugin is in daemon mode, but stdout/stderr "

			 "aren't redirected to /dev/null. Aborting.");

		fio_server_text_output(FIO_LOG_ERR, buf, sizeof(buf));

		return -1;

	}

examples/nvme/fio_plugin/fio_plugin.c

+30 −7
Original line number Diff line number Diff line
@@ -501,6 +501,27 @@ static void parse_pract_flag(int pract) 
	}

}



static bool

fio_redirected_to_dev_null(void)

{

	char path[PATH_MAX] = "";

	ssize_t ret;



	ret = readlink("/proc/self/fd/1", path, sizeof(path));



	if (ret == -1 || strcmp(path, "/dev/null") != 0) {

		return false;

	}



	ret = readlink("/proc/self/fd/2", path, sizeof(path));



	if (ret == -1 || strcmp(path, "/dev/null") != 0) {

		return false;

	}



	return true;

}



/* Called once at initialization. This is responsible for gathering the size of

 * each "file", which in our case are in the form

 * 'key=value [key=value] ... ns=value'
@@ -519,16 +540,18 @@ static int spdk_fio_setup(struct thread_data *td) 
	char *trid_info;

	unsigned int i;



	/* we might be running in a daemonized FIO instance where standard

	 * input and output were closed and fds 0, 1, and 2 are reused

	 * for something important by FIO. We can't ensure we won't print

	 * anything (and so will our dependencies, e.g. DPDK), so abort early.

	 * (is_backend is an fio global variable)

	/*

	 * If we're running in a daemonized FIO instance, it's possible

	 * fd 1/2 were re-used for something important by FIO. Newer fio

	 * versions are careful to redirect those to /dev/null, but if we're

	 * not, we'll abort early, so we don't accidentally write messages to

	 * an important file, etc.

	 */

	if (is_backend) {

	if (is_backend && !fio_redirected_to_dev_null()) {

		char buf[1024];

		snprintf(buf, sizeof(buf),

			 "SPDK FIO plugin won't work with daemonized FIO server.");

			 "SPDK FIO plugin is in daemon mode, but stdout/stderr "

			 "aren't redirected to /dev/null. Aborting.");

		fio_server_text_output(FIO_LOG_ERR, buf, sizeof(buf));

		return -1;

	}