xfs: fix rounding in xfs_free_file_space

The offset passed into xfs_free_file_space() needs to be rounded
down to a certain size, but the rounding mask is built by a 32 bit
variable. Hence the mask will always mask off the upper 32 bits of
the offset and lead to incorrect writeback and invalidation ranges.

This is not actually exposed as a bug because we writeback and
invalidate from the rounded offset to the end of the file, and hence
the offset we are actually punching a hole out of will always be
covered by the code. This needs fixing, however, if we ever want to
use exact ranges for writeback/invalidation here...
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit 28ca489c)

fs/xfs/xfs_vnodeops.c

@@ -1453,7 +1453,7 @@ xfs_free_file_space(
 	xfs_mount_t		*mp;
 	int			nimap;
 	uint			resblks;
-	uint			rounding;
+	xfs_off_t		rounding;
 	int			rt;
 	xfs_fileoff_t		startoffset_fsb;
 	xfs_trans_t		*tp;
@@ -1482,7 +1482,7 @@ xfs_free_file_space(
 		inode_dio_wait(VFS_I(ip));
 	}
 
-	rounding = max_t(uint, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
+	rounding = max_t(xfs_off_t, 1 << mp->m_sb.sb_blocklog, PAGE_CACHE_SIZE);
 	ioffset = offset & ~(rounding - 1);
 	error = -filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
 					      ioffset, -1);