Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw: (51 commits)
  [DLM] block dlm_recv in recovery transition
  [DLM] don't overwrite castparam if it's NULL
  [GFS2] Get superblock a different way
  [GFS2] Don't try to remove buffers that don't exist
  [GFS2] Alternate gfs2_iget to avoid looking up inodes being freed
  [GFS2] Data corruption fix
  [GFS2] Clean up journaled data writing
  [GFS2] GFS2: chmod hung - fix race in thread creation
  [DLM] Make dlm_sendd cond_resched more
  [GFS2] Move inode deletion out of blocking_cb
  [GFS2] flocks from same process trip kernel BUG at fs/gfs2/glock.c:1118!
  [GFS2] Clean up gfs2_trans_add_revoke()
  [GFS2] Use slab operations for all gfs2_bufdata allocations
  [GFS2] Replace revoke structure with bufdata structure
  [GFS2] Fix ordering of dirty/journal for ordered buffer unstuffing
  [GFS2] Clean up ordered write code
  [GFS2] Move pin/unpin into lops.c, clean up locking
  [GFS2] Don't mark jdata dirty in gfs2_unstuffer_page()
  [GFS2] Introduce gfs2_remove_from_ail
  [GFS2] Correct lock ordering in unlink
  ...

1 files changed, 10 insertions, 1 deletions

diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index 66575997861c..4b89e20eebe7 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -24,19 +24,28 @@
 
 
 /* If the start for which we're re-enabling locking (seq) has been superseded
-   by a newer stop (ls_recover_seq), we need to leave locking disabled. */
+   by a newer stop (ls_recover_seq), we need to leave locking disabled.
+
+   We suspend dlm_recv threads here to avoid the race where dlm_recv a) sees
+   locking stopped and b) adds a message to the requestqueue, but dlm_recoverd
+   enables locking and clears the requestqueue between a and b. */
 
 static int enable_locking(struct dlm_ls *ls, uint64_t seq)
 {
 	int error = -EINTR;
 
+	down_write(&ls->ls_recv_active);
+
 	spin_lock(&ls->ls_recover_lock);
 	if (ls->ls_recover_seq == seq) {
 		set_bit(LSFL_RUNNING, &ls->ls_flags);
+		/* unblocks processes waiting to enter the dlm */
 		up_write(&ls->ls_in_recovery);
 		error = 0;
 	}
 	spin_unlock(&ls->ls_recover_lock);
+
+	up_write(&ls->ls_recv_active);
 	return error;
 }