From 1c520dfbf391e1617ef61553f815b8006a066c44 Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Fri, 19 Jun 2009 15:14:13 -0700 Subject: ocfs2: Provide the ocfs2_dlm_lvb_valid() stack API. The Lock Value Block (LVB) of a DLM lock can be lost when nodes die and the DLM cannot reconstruct its state. Clients of the DLM need to know this. ocfs2's internal DLM, o2dlm, explicitly zeroes out the LVB when it loses track of the state. This is not a standard behavior, but ocfs2 has always relied on it. Thus, an o2dlm LVB is always "valid". ocfs2 now supports both o2dlm and fs/dlm via the stack glue. When fs/dlm loses track of an LVBs state, it sets a flag (DLM_SBF_VALNOTVALID) on the Lock Status Block (LKSB). The contents of the LVB may be garbage or merely stale. ocfs2 doesn't want to try to guess at the validity of the stale LVB. Instead, it should be checking the VALNOTVALID flag. As this is the 'standard' way of treating LVBs, we will promote this behavior. We add a stack glue API ocfs2_dlm_lvb_valid(). It returns non-zero when the LVB is valid. o2dlm will always return valid, while fs/dlm will check VALNOTVALID. Signed-off-by: Joel Becker Acked-by: Mark Fasheh --- fs/ocfs2/stack_user.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs/ocfs2/stack_user.c') diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c index 9b76d41a8ac6..ff4c798a5635 100644 --- a/fs/ocfs2/stack_user.c +++ b/fs/ocfs2/stack_user.c @@ -738,6 +738,13 @@ static int user_dlm_lock_status(union ocfs2_dlm_lksb *lksb) return lksb->lksb_fsdlm.sb_status; } +static int user_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb) +{ + int invalid = lksb->lksb_fsdlm.sb_flags & DLM_SBF_VALNOTVALID; + + return !invalid; +} + static void *user_dlm_lvb(union ocfs2_dlm_lksb *lksb) { if (!lksb->lksb_fsdlm.sb_lvbptr) @@ -873,6 +880,7 @@ static struct ocfs2_stack_operations ocfs2_user_plugin_ops = { .dlm_lock = user_dlm_lock, .dlm_unlock = user_dlm_unlock, .lock_status = user_dlm_lock_status, + .lvb_valid = user_dlm_lvb_valid, .lock_lvb = user_dlm_lvb, .plock = user_plock, .dump_lksb = user_dlm_dump_lksb, -- cgit v1.2.2