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,
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index bf12865..bb68c79 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -879,8 +879,8 @@
} else if (realdn) {
dout("dn %p (%d) spliced with %p (%d) "
"inode %p ino %llx.%llx\n",
- dn, atomic_read(&dn->d_count),
- realdn, atomic_read(&realdn->d_count),
+ dn, dn->d_count,
+ realdn, realdn->d_count,
realdn->d_inode, ceph_vinop(realdn->d_inode));
dput(dn);
dn = realdn;
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 38800ea..a50fca1 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1486,7 +1486,7 @@
*base = ceph_ino(temp->d_inode);
*plen = len;
dout("build_path on %p %d built %llx '%.*s'\n",
- dentry, atomic_read(&dentry->d_count), *base, len, path);
+ dentry, dentry->d_count, *base, len, path);
return path;
}