gfs2: Get rid of flush_delayed_work in gfs2_evict_inode

So far, gfs2_evict_inode clears gl->gl_object and then flushes the glock
work queue to make sure that inode glops which dereference gl->gl_object
have finished running before the inode is destroyed.  However, flushing
the work queue may do more work than needed, and in particular, it may
call into DLM, which we want to avoid here.  Use a bit lock
(GIF_GLOP_PENDING) to synchronize between the inode glops and
gfs2_evict_inode instead to get rid of the flushing.

In addition, flush the work queues of existing glocks before reusing
them for new inodes to get those glocks into a known state: the glock
state engine currently doesn't handle glock re-appropriation correctly.
(We may be able to fix the glock state engine instead later.)

Based on a patch by Steven Whitehouse <swhiteho@redhat.com>.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index ab1ef322f7a5..9ad4a6ac6c84 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -257,4 +257,11 @@ static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 	return gh->gh_gl;
 }
 
+static inline void glock_set_object(struct gfs2_glock *gl, void *object)
+{
+	spin_lock(&gl->gl_lockref.lock);
+	gl->gl_object = object;
+	spin_unlock(&gl->gl_lockref.lock);
+}
+
 #endif /* __GLOCK_DOT_H__ */