fs: dcache scale dentry refcount
Make d_count non-atomic and protect it with d_lock. This allows us to ensure a
0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when
we start protecting many other dentry members with d_lock.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index d902948..3ecf915 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -150,7 +150,9 @@
di = ceph_dentry(dentry);
}
- atomic_inc(&dentry->d_count);
+ spin_lock(&dentry->d_lock);
+ dentry->d_count++;
+ spin_unlock(&dentry->d_lock);
spin_unlock(&dcache_lock);
dout(" %llu (%llu) dentry %p %.*s %p\n", di->offset, filp->f_pos,