GFS2: Optimise glock lru and end of life inodes

The GLF_LRU flag introduced in the previous patch can be
used to check if a glock is on the lru list when a new
holder is queued and if so remove it, without having first
to get the lru_lock.

The main purpose of this patch however is to optimise the
glocks left over when an inode at end of life is being
evicted. Previously such glocks were left with the GLF_LFLUSH
flag set, so that when reclaimed, each one required a log flush.
This patch resets the GLF_LFLUSH flag when there is nothing
left to flush thus preventing later log flushes as glocks are
reused or demoted.

In order to do this, we need to keep track of the number of
revokes which are outstanding, and also to clear the GLF_LFLUSH
bit after a log commit when only revokes have been processed.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 48eb1ee..5067bea 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -236,6 +236,7 @@ struct gfs2_glock {
 
 	struct list_head gl_ail_list;
 	atomic_t gl_ail_count;
+	atomic_t gl_revokes;
 	struct delayed_work gl_work;
 	struct work_struct gl_delete;
 	struct rcu_head gl_rcu;