[PATCH] Change the global suspend event channel lock file to a per-domain lock file

[Shriram Rajagopalan <rshriram@cs.ubc.ca>]

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This allows multiple guests to be migrated or protected by Remus simultaneously.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>



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# HG changeset patch
# User rshriram@rshriram.cs.ubc.ca
# Date 1272409464 25200
# Node ID 6d2bca1b77539d1830372887e874b55a6f7781f9
# Parent  c87ec146229ab2255ecdf005b862b943b1a5112e
Change the global suspend event channel lock file to a per-domain lock file.
This allows multiple guests to be migrated or protected by Remus simultaneously.

Signed-off-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>

diff -r c87ec146229a -r 6d2bca1b7753 tools/libxc/xc_suspend.c
--- a/tools/libxc/xc_suspend.c	Fri Apr 23 15:04:26 2010 +0100
+++ b/tools/libxc/xc_suspend.c	Tue Apr 27 16:04:24 2010 -0700
@@ -7,18 +7,22 @@
 #include "xc_private.h"
 #include "xenguest.h"
 
-#define SUSPEND_LOCK_FILE "/var/lib/xen/suspend_evtchn_lock.d"
-static int lock_suspend_event(void)
+#define SUSPEND_LOCK_FILE "/var/lib/xen/suspend_evtchn"
+static int lock_suspend_event(int domid)
 {
     int fd, rc;
     mode_t mask;
     char buf[128];
+    char suspend_file[256];
 
+    snprintf(suspend_file, sizeof(suspend_file), "%s_%d_lock.d",
+	    SUSPEND_LOCK_FILE, domid);
     mask = umask(022);
-    fd = open(SUSPEND_LOCK_FILE, O_CREAT | O_EXCL | O_RDWR, 0666);
+    fd = open(suspend_file, O_CREAT | O_EXCL | O_RDWR, 0666);
     if (fd < 0)
     {
-        ERROR("Can't create lock file for suspend event channel\n");
+        ERROR("Can't create lock file for suspend event channel %s\n",
+		suspend_file);
         return -EINVAL;
     }
     umask(mask);
@@ -30,12 +34,15 @@
     return rc;
 }
 
-static int unlock_suspend_event(void)
+static int unlock_suspend_event(int domid)
 {
     int fd, pid, n;
     char buf[128];
+    char suspend_file[256];
 
-    fd = open(SUSPEND_LOCK_FILE, O_RDWR);
+    snprintf(suspend_file, sizeof(suspend_file), "%s_%d_lock.d",
+	    SUSPEND_LOCK_FILE, domid);
+    fd = open(suspend_file, O_RDWR);
 
     if (fd < 0)
         return -EINVAL;
@@ -50,7 +57,7 @@
         /* We are the owner, so we can simply delete the file */
         if (pid == getpid())
         {
-            unlink(SUSPEND_LOCK_FILE);
+            unlink(suspend_file);
             return 0;
         }
     }
@@ -77,19 +84,19 @@
     return 0;
 }
 
-int xc_suspend_evtchn_release(int xce, int suspend_evtchn)
+int xc_suspend_evtchn_release(int xce, int domid, int suspend_evtchn)
 {
     if (suspend_evtchn >= 0)
         xc_evtchn_unbind(xce, suspend_evtchn);
 
-    return unlock_suspend_event();
+    return unlock_suspend_event(domid);
 }
 
 int xc_suspend_evtchn_init(int xc, int xce, int domid, int port)
 {
     int rc, suspend_evtchn = -1;
 
-    if (lock_suspend_event())
+    if (lock_suspend_event(domid))
         return -EINVAL;
 
     suspend_evtchn = xc_evtchn_bind_interdomain(xce, domid, port);
@@ -111,7 +118,7 @@
 
 cleanup:
     if (suspend_evtchn != -1)
-        xc_suspend_evtchn_release(xce, suspend_evtchn);
+        xc_suspend_evtchn_release(xce, domid, suspend_evtchn);
 
     return -1;
 }
diff -r c87ec146229a -r 6d2bca1b7753 tools/libxc/xenguest.h
--- a/tools/libxc/xenguest.h	Fri Apr 23 15:04:26 2010 +0100
+++ b/tools/libxc/xenguest.h	Tue Apr 27 16:04:24 2010 -0700
@@ -157,7 +157,7 @@
                      const char *image_buffer,
                      unsigned long image_size);
 
-int xc_suspend_evtchn_release(int xce, int suspend_evtchn);
+int xc_suspend_evtchn_release(int xce, int domid, int suspend_evtchn);
 
 int xc_suspend_evtchn_init(int xc, int xce, int domid, int port);
 
diff -r c87ec146229a -r 6d2bca1b7753 tools/libxl/libxl_dom.c
--- a/tools/libxl/libxl_dom.c	Fri Apr 23 15:04:26 2010 +0100
+++ b/tools/libxl/libxl_dom.c	Tue Apr 27 16:04:24 2010 -0700
@@ -326,7 +326,7 @@
                    &core_suspend_switch_qemu_logdirty);
 
     if (si.suspend_eventchn > 0)
-        xc_suspend_evtchn_release(si.xce, si.suspend_eventchn);
+        xc_suspend_evtchn_release(si.xce, domid, si.suspend_eventchn);
     if (si.xce > 0)
         xc_evtchn_close(si.xce);
 
diff -r c87ec146229a -r 6d2bca1b7753 tools/python/xen/lowlevel/checkpoint/libcheckpoint.c
--- a/tools/python/xen/lowlevel/checkpoint/libcheckpoint.c	Fri Apr 23 15:04:26 2010 +0100
+++ b/tools/python/xen/lowlevel/checkpoint/libcheckpoint.c	Tue Apr 27 16:04:24 2010 -0700
@@ -360,7 +360,7 @@
 {
   /* TODO: teach xen to clean up if port is unbound */
   if (s->xce >= 0 && s->suspend_evtchn >= 0) {
-    xc_suspend_evtchn_release(s->xce, s->suspend_evtchn);
+    xc_suspend_evtchn_release(s->xce, s->domid, s->suspend_evtchn);
     s->suspend_evtchn = -1;
   }
 }
diff -r c87ec146229a -r 6d2bca1b7753 tools/xcutils/xc_save.c
--- a/tools/xcutils/xc_save.c	Fri Apr 23 15:04:26 2010 +0100
+++ b/tools/xcutils/xc_save.c	Tue Apr 27 16:04:24 2010 -0700
@@ -210,7 +210,7 @@
                          &switch_qemu_logdirty);
 
     if (si.suspend_evtchn > 0)
-        xc_suspend_evtchn_release(si.xce, si.suspend_evtchn);
+	 xc_suspend_evtchn_release(si.xce, si.domid, si.suspend_evtchn);
 
     if (si.xce > 0)
         xc_evtchn_close(si.xce);

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