From 3c5ec3835d5fd57a993cb814ecd74b48419a7459 Mon Sep 17 00:00:00 2001

From: Mike Christie <michaelc@cs.wisc.edu>

Date: Mon, 29 Jul 2013 14:13:36 -0500

Subject: Make rescan run in parallel

Patch from Saggi Mizrahi:

This fixes a problem where a host which is inaccessible would block the

scan of other hosts in the system.

[compilation and minor cosmetic fixes by Mike Christie]

Signed-off-by: Saggi Mizrahi <smizrahi@redhat.com>

---

 usr/host.c         |  2 +-

 usr/initiator.c    |  3 ++-

 usr/iscsi_sysfs.c  | 61 +++++++++++++++++++++++++++++++++++++++++++++---------

 usr/iscsi_sysfs.h  |  3 ++-

 usr/iscsiadm.c     | 18 +++++++++-------

 usr/iscsid.c       |  3 ++-

 usr/session_info.c |  4 ++--

 usr/session_mgmt.c |  7 ++++---

 8 files changed, 74 insertions(+), 27 deletions(-)

diff --git a/usr/host.c b/usr/host.c

index b03e50f..1fcb350 100644

--- a/usr/host.c

+++ b/usr/host.c

@@ -242,7 +242,7 @@ static int host_info_print_tree(void *data, struct host_info *hinfo)

 	link_info.data = &hinfo->host_no;

 	err = iscsi_sysfs_for_each_session(&link_info, &num_found,

-					   session_info_create_list);

+					   session_info_create_list, 0);

 	if (err || !num_found)

 		return 0;

diff --git a/usr/initiator.c b/usr/initiator.c

index 86df222..a3b24b7 100644

--- a/usr/initiator.c

+++ b/usr/initiator.c

@@ -1855,7 +1855,8 @@ static int session_is_running(node_rec_t *rec)

 	if (session_find_by_rec(rec))

 		return 1;

-	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_session))

+	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_session,

+					 0))

 		return 1;

 	return 0;

diff --git a/usr/iscsi_sysfs.c b/usr/iscsi_sysfs.c

index 64a4ce7..aed10a3 100644

--- a/usr/iscsi_sysfs.c

+++ b/usr/iscsi_sysfs.c

@@ -24,6 +24,7 @@

 #include <dirent.h>

 #include <sys/types.h>

 #include <sys/stat.h>

+#include <sys/wait.h>

 #include "log.h"

 #include "initiator.h"

@@ -1167,11 +1168,13 @@ int iscsi_sysfs_get_sessioninfo_by_id(struct session_info *info, char *session)

 }

 int iscsi_sysfs_for_each_session(void *data, int *nr_found,

-				 iscsi_sysfs_session_op_fn *fn)

+				 iscsi_sysfs_session_op_fn *fn,

+				 int in_parallel)

 {

 	struct dirent **namelist;

-	int rc = 0, n, i;

+	int rc = 0, n, i, chldrc = 0;

 	struct session_info *info;

+	pid_t pid = 0;

 	info = calloc(1, sizeof(*info));

 	if (!info)

@@ -1193,14 +1196,52 @@ int iscsi_sysfs_for_each_session(void *data, int *nr_found,

 			continue;

 		}

-		rc = fn(data, info);

-		if (rc > 0)

-			break;

-		else if (rc == 0)

-			(*nr_found)++;

-		else

-			/* if less than zero it means it was not a match */

-			rc = 0;

+		if (in_parallel) {

+			pid = fork();

+		}

+		if (pid == 0) {

+			rc = fn(data, info);

+			if (in_parallel) {

+				exit(rc);

+			} else {

+				if (rc > 0) {

+					break;

+				} else if (rc == 0) {

+					(*nr_found)++;

+				} else {

+					/* if less than zero it means it was not a match */

+					rc = 0;

+				}

+			}

+		} else if (pid < 0) {

+			log_error("could not fork() for session %s, err %d",

+				   namelist[i]->d_name, errno);

+		}

+	}

+

+	if (in_parallel) {

+		while (1) {

+			if (wait(&chldrc) < 0) {

+				/*

+				 * ECHILD means no more children which is

+				 * expected to happen sooner or later.

+				 */

+				if (errno != ECHILD) {

+					rc = errno;

+				}

+				break;

+			}

+

+			if ((chldrc > 0) && (rc == 0)) {

+				/*

+				 * The non-parallel code path returns the first

+				 * error so this keeps the same semantics.

+				 */

+				rc = chldrc;

+			} else if (chldrc == 0) {

+				(*nr_found)++;

+			}

+		}

 	}

 	for (i = 0; i < n; i++)

diff --git a/usr/iscsi_sysfs.h b/usr/iscsi_sysfs.h

index d130d36..9a56105 100644

--- a/usr/iscsi_sysfs.h

+++ b/usr/iscsi_sysfs.h

@@ -51,7 +51,8 @@ extern int iscsi_sysfs_for_each_iface_on_host(void *data, uint32_t host_no,

 					      int *nr_found,

 					      iscsi_sysfs_iface_op_fn *fn);

 extern int iscsi_sysfs_for_each_session(void *data, int *nr_found,

-					iscsi_sysfs_session_op_fn *fn);

+					iscsi_sysfs_session_op_fn *fn,

+					int in_parallel);

 extern int iscsi_sysfs_for_each_host(void *data, int *nr_found,

 				     iscsi_sysfs_host_op_fn *fn);

 extern uint32_t iscsi_sysfs_get_host_no_from_sid(uint32_t sid, int *err);

diff --git a/usr/iscsiadm.c b/usr/iscsiadm.c

index 5030894..da0a3ec 100644

--- a/usr/iscsiadm.c

+++ b/usr/iscsiadm.c

@@ -347,7 +347,8 @@ match_startup_mode(node_rec_t *rec, char *mode)

 }

 static int

-for_each_session(struct node_rec *rec, iscsi_sysfs_session_op_fn *fn)

+for_each_session(struct node_rec *rec, iscsi_sysfs_session_op_fn *fn,

+		 int in_parallel)

 {

 	int err, num_found = 0;

@@ -355,7 +356,8 @@ for_each_session(struct node_rec *rec, iscsi_sysfs_session_op_fn *fn)

 		num_found = 1;

 		err = fn(rec, rec->session.info);

 	} else {

-		err = iscsi_sysfs_for_each_session(rec, &num_found, fn);

+		err = iscsi_sysfs_for_each_session(rec, &num_found, fn,

+						   in_parallel);

 	}

 	if (err)

 		log_error("Could not execute operation on all sessions: %s",

@@ -435,7 +437,7 @@ logout_by_startup(char *mode)

 	rc = iscsi_logout_portals(mode, &nr_found, 1, __logout_by_startup);

 	if (rc == ISCSI_ERR_NO_OBJS_FOUND)

 		log_error("No matching sessions found");

-	return rc; 

+	return rc;

 }

 struct startup_data {

@@ -479,7 +481,7 @@ __do_leading_login(void *data, struct list_head *list, struct node_rec *rec)

 	 * If there is an existing session that matcthes the target,

 	 * the leading login is complete.

 	 */

-	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_target)) {

+	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_target, 0)) {

 		log_debug(1, "Skipping %s: Already a session for that target",

 			  rec->name);

 		return -1;

@@ -579,7 +581,7 @@ login_by_startup(char *mode)

 		list_for_each_entry_safe(rec, tmp_rec, &startup.leading_logins,

 					 list) {

 			if (!iscsi_sysfs_for_each_session(rec, &nr_found,

-							  iscsi_match_target))

+							  iscsi_match_target, 0))

 				missed_leading_login++;

 			/*

 			 * Cleanup the list, since 'iscsi_login_portals_safe'

@@ -1210,7 +1212,7 @@ do_target_discovery(discovery_rec_t *drec, struct list_head *ifaces,

 		host_no = iscsi_sysfs_get_host_no_from_hwinfo(iface, &rc);

 		if (rc || host_no == -1) {

 			log_debug(1, "Could not match iface" iface_fmt " to "

-				  "host.", iface_str(iface)); 

+				  "host.", iface_str(iface));

 			/* try software iscsi */

 			continue;

 		}

@@ -2116,12 +2118,12 @@ static int exec_node_op(int op, int do_login, int do_logout,

 	}

 	if (do_rescan) {

-		rc = for_each_session(rec, rescan_portal);

+		rc = for_each_session(rec, rescan_portal, 1);

 		goto out;

 	}

 	if (do_stats) {

-		rc = for_each_session(rec, session_stats);

+		rc = for_each_session(rec, session_stats, 0);

 		goto out;

 	}

diff --git a/usr/iscsid.c b/usr/iscsid.c

index b4bb65b..8f19220 100644

--- a/usr/iscsid.c

+++ b/usr/iscsid.c

@@ -511,7 +511,8 @@ int main(int argc, char *argv[])

 	if (pid == 0) {

 		int nr_found = 0;

 		/* child */

-		iscsi_sysfs_for_each_session(NULL, &nr_found, sync_session);

+		/* TODO - test with async support enabled */

+		iscsi_sysfs_for_each_session(NULL, &nr_found, sync_session, 0);

 		exit(0);

 	} else if (pid < 0) {

 		log_error("Fork failed error %d: existing sessions"

diff --git a/usr/session_info.c b/usr/session_info.c

index 1f84c49..de156c6 100644

--- a/usr/session_info.c

+++ b/usr/session_info.c

@@ -368,7 +368,7 @@ int session_info_print(int info_level, struct session_info *info, int do_show)

 			num_found = 1;

 		} else

 			err = iscsi_sysfs_for_each_session(info, &num_found,

-						   session_info_print_flat);

+						   session_info_print_flat, 0);

 		break;

 	case 3:

 		version = iscsi_sysfs_get_iscsi_kernel_version();

@@ -403,7 +403,7 @@ int session_info_print(int info_level, struct session_info *info, int do_show)

 		link_info.match_fn = NULL;

 		err = iscsi_sysfs_for_each_session(&link_info, &num_found,

-						   session_info_create_list);

+						   session_info_create_list, 0);

 		if (err || !num_found)

 			break;

diff --git a/usr/session_mgmt.c b/usr/session_mgmt.c

index 0b7373f..87b8e00 100644

--- a/usr/session_mgmt.c

+++ b/usr/session_mgmt.c

@@ -172,7 +172,7 @@ int iscsi_login_portal(void *data, struct list_head *list, struct node_rec *rec)

 	 * that are missing.

 	 */

 	rc = iscsi_sysfs_for_each_session(rec, &session_count,

-					  iscsi_match_session_count);

+					  iscsi_match_session_count, 0);

 	if (rc) {

 		log_error("Could not count current number of sessions");

 		goto done;

@@ -421,7 +421,7 @@ int iscsi_logout_portals(void *data, int *nr_found, int wait,

 	*nr_found = 0;

 	err = iscsi_sysfs_for_each_session(&link_info, nr_found,

-					   session_info_create_list);

+					   session_info_create_list, 0);

 	if (err && !list_empty(&session_list))

 		log_error("Could not read in all sessions: %s",

 			  iscsi_err_to_str(err));

@@ -466,7 +466,8 @@ free_list:

 int iscsi_check_for_running_session(struct node_rec *rec)

 {

 	int nr_found = 0;

-	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_session))

+	if (iscsi_sysfs_for_each_session(rec, &nr_found, iscsi_match_session,

+					 0))

 		return 1;

 	return 0;

 }

-- 

1.8.1.4