udf: Fix off-by-one error when discarding preallocation

[ Upstream commit f54aa97fb7 ]

The condition determining whether the preallocation can be used had
an off-by-one error so we didn't discard preallocation when new
allocation was just following it. This can then confuse code in
inode_getblk().

CC: stable@vger.kernel.org
Fixes: 16d0556568 ("udf: Discard preallocation before extending file with a hole")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/udf/inode.c

@@ -442,7 +442,7 @@ static int udf_get_block(struct inode *inode, sector_t block,
 	 * Block beyond EOF and prealloc extents? Just discard preallocation
 	 * as it is not useful and complicates things.
 	 */
-	if (((loff_t)block) << inode->i_blkbits > iinfo->i_lenExtents)
+	if (((loff_t)block) << inode->i_blkbits >= iinfo->i_lenExtents)
 		udf_discard_prealloc(inode);
 	udf_clear_extent_cache(inode);
 	phys = inode_getblk(inode, block, &err, &new);