From: Christoph Hellwig <hch@lst.de>
Date: Thu, 20 Oct 2016 04:49:03 +0000 (+1100)
Subject: xfs: fix the same_inode check in xfs_file_share_range
X-Git-Tag: v4.9-rc3~32^2~15
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=a62e82b35b97e60e9e22a4e303900f342139822f;p=linux.git

xfs: fix the same_inode check in xfs_file_share_range

The VFS i_ino is an unsigned long, while XFS inode numbers are 64-bit
wide, so checking i_ino for equality could lead to rate false positives
on 32-bit architectures.  Just compare the inode pointers themselves
to be safe.

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

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 194f8f396e4d..d5b835e82b2d 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -965,7 +965,7 @@ xfs_file_share_range(
 	    IS_SWAPFILE(inode_out))
 		return -ETXTBSY;
 
-	same_inode = (inode_in->i_ino == inode_out->i_ino);
+	same_inode = (inode_in == inode_out);
 
 	/* Don't reflink dirs, pipes, sockets... */
 	if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))