From 62aab20f08758b1b171a73a54e0c72dd12beb980 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Mon, 3 Oct 2016 09:11:23 -0700
Subject: xfs: adjust refcount when unmapping file blocks

When we're unmapping blocks from a reflinked file, decrease the
refcount of the affected blocks and free the extents that are no
longer in use.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 9d7f61d..907d7b8d 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -48,6 +48,7 @@
 #include "xfs_filestream.h"
 #include "xfs_rmap.h"
 #include "xfs_ag_resv.h"
+#include "xfs_refcount.h"
 
 
 kmem_zone_t		*xfs_bmap_free_item_zone;
@@ -4988,9 +4989,16 @@ xfs_bmap_del_extent(
 	/*
 	 * If we need to, add to list of extents to delete.
 	 */
-	if (do_fx)
-		xfs_bmap_add_free(mp, dfops, del->br_startblock,
-				del->br_blockcount, NULL);
+	if (do_fx) {
+		if (xfs_is_reflink_inode(ip) && whichfork == XFS_DATA_FORK) {
+			error = xfs_refcount_decrease_extent(mp, dfops, del);
+			if (error)
+				goto done;
+		} else
+			xfs_bmap_add_free(mp, dfops, del->br_startblock,
+					del->br_blockcount, NULL);
+	}
+
 	/*
 	 * Adjust inode # blocks in the file.
 	 */
-- 
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