Recent Linux NFS uses a simulated attibute cache change detection

method based on ctime. Consequenty the amd use of mtime for this
doesn't work properly for some kernel versions.

The problem seen with some kernel versions is a failure to recognize
umounts.

Updating the parent ctime in step with mtime during umount appears
to fix the problem.

From: Ian Kent

diff --git a/amd/autil.c b/amd/autil.c
index cd9514d44ef4b76079c06833d017979729a3f327..efd18ef4202f1f03ed41a91d1c2c779c51dbd95e 100644 (file)
--- a/amd/autil.c
+++ b/amd/autil.c
@@ -709,10 +709,13 @@ am_unmounted(am_node *mp)
     --mp->am_parent->am_fattr.na_nlink;
 
   /*
-   * Update mtime of parent node
+   * Update mtime and ctime of parent node (as ctime is needed for some
+   * Linux NFS kernel versions to properly recognize attribute changes).
    */
-  if (mp->am_parent && mp->am_parent->am_al->al_mnt)
+  if (mp->am_parent && mp->am_parent->am_al->al_mnt) {
     clocktime(&mp->am_parent->am_fattr.na_mtime);
+    mp->am_parent->am_fattr.na_ctime = mp->am_parent->am_fattr.na_mtime;
+  }
 
   if (mp->am_parent && (mp->am_flags & AMF_REMOUNT)) {
     char *fname = xstrdup(mp->am_name);