tree c42f93313e79afecfda220fd134f953bdaaaaf56
parent db1866ffeed2e142208a801f7598326b92ebf7c5
author Lars Ellenberg <lars.ellenberg@linbit.com> 1399291554 +0000
committer Philipp Reisner <philipp.reisner@linbit.com> 1405010117 +0200

drbd: debugfs: deal with destructor racing with open of debugfs file

Try to close the race between open() and debugfs_remove_recursive()
from inside an object destructor.
Once open succeeds, the object should stay around.
Open should not succeed if the object has already reached its destructor.

This may be overkill, but to make that happen, we check for existence of
a parent directory, "stale-ness" of "this" dentry, and serialize
kref_get_unless_zero() on the outermost object relevant for this file
with d_delete() on this dentry (using the parent's i_mutex).

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>