IMA: maintain i_readcount in the VFS layer

ima_counts_get() updated the readcount and invalidated the PCR,
as necessary. Only update the i_readcount in the VFS layer.
Move the PCR invalidation checks to ima_file_check(), where it
belongs.

Maintaining the i_readcount in the VFS layer, will allow other
subsystems to use i_readcount.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/file_table.c b/fs/file_table.c
index c3dee38..0c724de 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -190,7 +190,8 @@
 		file_take_write(file);
 		WARN_ON(mnt_clone_write(path->mnt));
 	}
-	ima_counts_get(file);
+	if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+		i_readcount_inc(path->dentry->d_inode);
 	return file;
 }
 EXPORT_SYMBOL(alloc_file);
@@ -251,6 +252,8 @@
 	fops_put(file->f_op);
 	put_pid(file->f_owner.pid);
 	file_sb_list_del(file);
+	if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+		i_readcount_dec(inode);
 	if (file->f_mode & FMODE_WRITE)
 		drop_file_write_access(file);
 	file->f_path.dentry = NULL;