[dm-devel] [PATCH] libmultipath: fix multipath -q command logic

[tang.junhui at zte.com.cn]

Please have a review for this patch, any comment will be highly 
appreciated.




发件人:         tang.junhui at zte.com.cn
收件人:         christophe varoqui <christophe.varoqui at free.fr>, 
抄送:   dm-devel at redhat.com, zhang.kai16 at zte.com.cn, "tang.junhui" 
<tang.junhui at zte.com.cn>
日期:   2016/08/16 19:33
主题:   [PATCH] libmultipath: fix multipath -q command logic



From: "tang.junhui" <tang.junhui at zte.com.cn>

multipath judged whether multipathd service in running by check_daemon() 
when executing
mutipath commands, check_daemon() try to connect to the multipathd service 
and execute
"show dameon" command. The expected result is that the command will be 
failed when the
service is not running, however, mpath_connect() will activate the 
multipathd service when
the service is not running, so check_daemon() always return with true. 
Another problem is that
multipath command with -q parameter is not processed in coalesce_paths(). 
This patch fix for
those two problems.

Signed-off-by: tang.junhui <tang.junhui at zte.com.cn>
---
 libmultipath/configure.c | 85 
+++++++++++++++++++++++++++---------------------
 1 file changed, 48 insertions(+), 37 deletions(-)

diff --git a/libmultipath/configure.c b/libmultipath/configure.c
index 707e6be..d8a17a6 100644
--- a/libmultipath/configure.c
+++ b/libmultipath/configure.c
@@ -715,36 +715,36 @@ deadmap (struct multipath * mpp)
                 return 1; /* dead */
 }
 
-int check_daemon(void)
+static int
+check_daemon(void)
 {
                 int fd;
-                char *reply;
-                int ret = 0;
-                unsigned int timeout;
-                struct config *conf;
-
-                fd = mpath_connect();
-                if (fd == -1)
-                                return 0;
+                struct flock lock;
 
-                if (send_packet(fd, "show daemon") != 0)
-                                goto out;
-                conf = get_multipath_config();
-                timeout = conf->uxsock_timeout;
-                put_multipath_config(conf);
-                if (recv_packet(fd, &reply, timeout) != 0)
-                                goto out;
-
-                if (strstr(reply, "shutdown"))
-                                goto out_free;
-
-                ret = 1;
+                fd = open(DEFAULT_PIDFILE, O_RDONLY);
+                if (fd < 0) {
+                                if (errno == ENOENT)
+                                                return 0;
+                                if (errno == EMFILE)
+                                                condlog(0, "failed to 
open file, increase max_fds at %s", DEFAULT_CONFIGFILE);
+                                else
+                                                condlog(0, "can not open 
pidfile %s: %s", DEFAULT_PIDFILE, strerror(errno));
+                                return -1;
+                }
 
-out_free:
-                FREE(reply);
-out:
-                mpath_disconnect(fd);
-                return ret;
+                lock.l_type = F_WRLCK;
+                lock.l_start = 0;
+                lock.l_whence = SEEK_SET;
+                lock.l_len = 0;
+                if (fcntl(fd, F_GETLK, &lock) < 0) {
+                                condlog(0, "can not get file locker, %s: 
%s", DEFAULT_PIDFILE, strerror(errno));
+                                close(fd);
+                                return -1;
+                }
+                close(fd);
+                if (lock.l_type == F_UNLCK)
+                                return 0;
+                return 1;
 }
 
 extern int
@@ -873,17 +873,28 @@ coalesce_paths (struct vectors * vecs, vector newmp, 
char * refwwid, int force_r
                                 if (r == DOMAP_DRY)
                                                 continue;
 
-                                conf = get_multipath_config();
-                                allow_queueing = conf->allow_queueing;
-                                put_multipath_config(conf);
-                                if (!is_daemon && !allow_queueing && 
!check_daemon()) {
-                                                if (mpp->no_path_retry != 
NO_PATH_RETRY_UNDEF &&
-                                                    mpp->no_path_retry != 
NO_PATH_RETRY_FAIL)
- condlog(3, "%s: multipathd not running, unset "
-  "queue_if_no_path feature", mpp->alias);
-                                                if 
(!dm_queue_if_no_path(mpp->alias, 0))
- remove_feature(&mpp->features,
-         "queue_if_no_path");
+                                /* run as multipath command and the 
service is not running */
+                                if (!is_daemon && !check_daemon()) {
+                                                conf = 
get_multipath_config();
+                                                allow_queueing = 
conf->allow_queueing;
+ put_multipath_config(conf);
+                                                /* no -q choice */
+                                                if (!allow_queueing) {
+                                                                if 
(mpp->no_path_retry != NO_PATH_RETRY_UNDEF &&
+  mpp->no_path_retry != NO_PATH_RETRY_FAIL)
+  condlog(3, "%s: multipathd not running, unset "
+                "queue_if_no_path feature", mpp->alias);
+                                                                if 
(!dm_queue_if_no_path(mpp->alias, 0))
+  remove_feature(&mpp->features,
+                                "queue_if_no_path");
+                                                } else { /* with -q 
choice */
+                                                                if 
(mpp->no_path_retry == NO_PATH_RETRY_UNDEF ||
+  mpp->no_path_retry == NO_PATH_RETRY_FAIL)
+  condlog(3, "%s: multipathd not running, set "
+                "queue_if_no_path feature", mpp->alias);
+                                                                if 
(!dm_queue_if_no_path(mpp->alias, 1))
+  add_feature(&mpp->features, "queue_if_no_path");
+                                                }
                                 }
                                 else if (mpp->no_path_retry != 
NO_PATH_RETRY_UNDEF) {
                                                 if (mpp->no_path_retry == 
NO_PATH_RETRY_FAIL) {
-- 
2.8.1.windows.1



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