From 9b0899aa3d6f6a65ac3af131193be792e29373e9 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Thu, 30 Oct 2014 10:35:00 +1100
Subject: mm: Remove false WARN_ON from pagecache_isize_extended()

commit f55fefd1a5a339b1bd08c120b93312d6eb64a9fb upstream.

The WARN_ON checking whether i_mutex is held in
pagecache_isize_extended() was wrong because some filesystems (e.g.
XFS) use different locks for serialization of truncates / writes. So
just remove the check.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 mm/truncate.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/mm/truncate.c b/mm/truncate.c
index ef13a0753996..143883a59046 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -608,7 +608,6 @@ void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to)
 	struct page *page;
 	pgoff_t index;
 
-	WARN_ON(!mutex_is_locked(&inode->i_mutex));
 	WARN_ON(to > inode->i_size);
 
 	if (from >= to || bsize == PAGE_CACHE_SIZE)
-- 
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