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/autofs4/root.c b/fs/autofs4/root.c
index d34896c..7922509 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -436,7 +436,7 @@
spin_lock(&active->d_lock);
/* Already gone? */
- if (atomic_read(&active->d_count) == 0)
+ if (active->d_count == 0)
goto next;
qstr = &active->d_name;
@@ -452,7 +452,7 @@
goto next;
if (d_unhashed(active)) {
- dget(active);
+ dget_dlock(active);
spin_unlock(&active->d_lock);
spin_unlock(&sbi->lookup_lock);
spin_unlock(&dcache_lock);
@@ -507,7 +507,7 @@
goto next;
if (d_unhashed(expiring)) {
- dget(expiring);
+ dget_dlock(expiring);
spin_unlock(&expiring->d_lock);
spin_unlock(&sbi->lookup_lock);
spin_unlock(&dcache_lock);