fs/jfs: TRIM support for JFS Filesystem

This patch adds support for the two linux interfaces of the discard/TRIM
command for SSD devices and sparse/thinly-provisioned LUNs.

JFS will support batched discard via FITRIM ioctl and online discard
with the discard mount option.

Signed-off-by: Tino Reichardt <list-jfs@mcmilk.de>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
diff --git a/fs/jfs/jfs_discard.h b/fs/jfs/jfs_discard.h
new file mode 100644
index 0000000..40d1ee6
--- /dev/null
+++ b/fs/jfs/jfs_discard.h
@@ -0,0 +1,26 @@
+/*
+ *   Copyright (C) Tino Reichardt, 2012
+ *
+ *   This program is free software;  you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program;  if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#ifndef _H_JFS_DISCARD
+#define _H_JFS_DISCARD
+
+struct fstrim_range;
+
+extern void jfs_issue_discard(struct inode *ip, u64 blkno, u64 nblocks);
+extern int jfs_ioc_trim(struct inode *ip, struct fstrim_range *range);
+
+#endif /* _H_JFS_DISCARD */