duplicate ids in /proc/locks
Red Hat Enterprise Linux Server release 5.4 (Tikanga)
2.6.18-164.11.1.el5xen (Xen release for virtualisation)
I'm trying to track down a problem with a utility that used to work and now hangs indefinitely. Since its hanging, I suspected a locking problem, and went to have a look for the process ids in /proc/locks; I get:
148: FLOCK ADVISORY WRITE 30279 ca:21:49153 0 EOF
148: -> FLOCK ADVISORY READ 30282 ca:21:49153 0 EOF
Now as near as I can tell this shouldn't be my problem, since the two ADVISORY locks - one READ and one WRITE - shouldn't conflict with one another. But I'd like to understand it all the same. I haven't been able to find any kind of definitive guide for the format of /proc/locks entries, but what I did find in the manuals specifically states:
"Each lock has its own line which starts with a unique number. "
Which is obviously not true; both of my lines start with the same number. Also, since most search engines don't seem to play nicely with symbols, I can't find any reference to what the "->" means. Can anyone explain? Or point me to a good reference?