Re: mpath_ctl observation + some novice questions

On Thu, Sep 15, 2005 at 09:25:38AM -0400, Ray Stell wrote:
> I'm not a developer, but I thought I'd throw out this observation.
> 
> environment:
>  - rhas4 U2 Beta - Linux pecan 2.6.9-16.EL #1 Mon Aug 15 19:58:49 EDT 2005 
> i686 i686 i386 GNU/Linux
>  - multipath-tools-0.4.5.49.  

RPM (which?) or built from source tarball?

> The cpu got eaten up by mpath_ctl and remains that way until reboot:

The latest RPM is device-mapper-multipath-0.4.5-6.0.RHEL4
which contains a patch (attached) that should fix this.

(uxsock.c where this code came from may also have similar issues)

Alasdair
-- 
agk@xxxxxxxxxx


--- multipath-tools-0.4.5.49/multipath/mpath_faker.c    2005-08-01 
22:07:57.000000000 +0100
+++ multipath-tools-0.4.5.49.1/multipath/mpath_faker.c  2005-09-02 
22:55:55.000000000 +0100
@@ -8,17 +8,22 @@
 #include "uxsock.h"
 
 /*
- * keep writing until its all sent
+ * keep writing until it's all sent
  */
-int write_all(int fd, const void *buf, size_t len)
+size_t write_all(int fd, const void *buf, size_t len)
 {
        size_t total = 0;
+
        while (len) {
-               int n = write(fd, buf, len);
+               ssize_t n = write(fd, buf, len);
                if (n < 0) {
+                       if ((errno == EINTR) || (errno == EAGAIN))
+                               continue;
                        perror("failed to send message to multipathd");
                        return total;
                }
+               if (!n)
+                       return total;
                buf = n + (char *)buf;
                len -= n;
                total += n;
@@ -30,19 +35,25 @@ int write_all(int fd, const void *buf, s
 /*
  * keep reading until its all read
  */
-int read_all(int fd, void *buf, size_t len)
+size_t read_all(int fd, void *buf, size_t len)
 {
        size_t total = 0;
+
        while (len) {
-               int n = read(fd, buf, len);
+               ssize_t n = read(fd, buf, len);
                if (n < 0) {
+                       if ((errno == EINTR) || (errno == EAGAIN))
+                               continue;
                        perror("failed to receive message from multipathd");
                        return total;
                }
+               if (!n)
+                       return total;
                buf = n + (char *)buf;
                len -= n;
                total += n;
        }
+
        return total;
 }
 
@@ -57,7 +68,7 @@ int main(int argc, char **argv)
 {
        int sock;
        struct sockaddr_un sun;
-       int len;
+       size_t len;
        char reply[6];
 
        if (argc == 1 || (!strcmp(argv[1], "-h")) ||
@@ -103,6 +114,6 @@ int main(int argc, char **argv)
                exit(1);
        }
        close(sock);
+
        return 0;
 }
-