From: tang.junhui <tang.jun...@zte.com.cn>

Before merging uevents, these uevents are going to be filtered:
1) Change or addition uevent of a removed path (it indicate by an
deletion uevent occurred later), and
2) Change uevent if addition uevent of a path has not ever been
proccessed.

Change-Id: If00c2c2e23ea466c1d4643c541ed2d8f9a0c8dea
Signed-off-by: tang.junhui <tang.jun...@zte.com.cn>
---
 libmultipath/uevent.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/libmultipath/uevent.c b/libmultipath/uevent.c
index 7282a51..838f128 100644
--- a/libmultipath/uevent.c
+++ b/libmultipath/uevent.c
@@ -144,6 +144,40 @@ uevent_can_discard(struct uevent *uev)
 }
 
 bool
+uevent_can_filter(struct uevent *earlier, struct uevent *later)
+{
+
+       /*
+        * filter earlier uvents if path has removed later. Eg:
+        * "add path1 |chang path1 |add path2 |remove path1"
+        * can filter as:
+        * "add path2 |remove path1"
+        * uevents "add path1" and "chang path1" are filtered out
+        */
+       if (!strcmp(earlier->kernel, later->kernel) &&
+               !strcmp(later->action, "remove") &&
+               strncmp(later->kernel, "dm-", 3)) {
+               return true;
+       }
+
+       /*
+        * filter change uvents if add uevents exist. Eg:
+        * "change path1| add path1 |add path2"
+        * can filter as:
+        * "add path1 |add path2"
+        * uevent "chang path1" is filtered out
+        */
+       if (!strcmp(earlier->kernel, later->kernel) &&
+               !strcmp(earlier->action, "change") &&
+               !strcmp(later->action, "add") &&
+               strncmp(later->kernel, "dm-", 3)) {
+               return true;
+       }
+
+       return false;
+}
+
+bool
 merge_need_stop(struct uevent *earlier, struct uevent *later)
 {
        /*
@@ -215,6 +249,29 @@ uevent_discard(struct list_head *tmpq)
 }
 
 void
+uevent_filter(struct uevent *later, struct list_head *tmpq)
+{
+       struct uevent *earlier, *tmp;
+
+       list_for_some_entry_reverse_safe(earlier, tmp, &later->node, tmpq, 
node) {
+               /*
+                * filter unnessary earlier uevents 
+                * by the later uevent
+                */
+               if (uevent_can_filter(earlier, later)) {
+                       condlog(2, "uevent: %s-%s has filtered by uevent: 
%s-%s",
+                               earlier->kernel, earlier->action, 
+                               later->kernel, later->action);
+
+                       list_del_init(&earlier->node);
+                       if (earlier->udev)
+                               udev_device_unref(earlier->udev);
+                       FREE(earlier);
+               }
+       }
+}
+
+void
 uevent_merge(struct uevent *later, struct list_head *tmpq)
 {
        struct uevent *earlier, *tmp;
@@ -242,6 +299,7 @@ merge_uevq(struct list_head *tmpq)
 
        uevent_discard(tmpq);
        list_for_each_entry_reverse(later, tmpq, node) {
+               uevent_filter(later, tmpq);
                uevent_merge(later, tmpq);
        }
 }
-- 
2.8.1.windows.1


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