From 7acb32a4aae236b12d22e3273f54358c74209ef0 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Mon, 11 Mar 2019 15:04:18 +0100
Subject: [PATCH] udf: Fix crash on IO error during truncate

BugLink: https://bugs.launchpad.net/bugs/1822671

commit d3ca4651d05c0ff7259d087d8c949bcf3e14fb46 upstream.

When truncate(2) hits IO error when reading indirect extent block the
code just bugs with:

kernel BUG at linux-4.15.0/fs/udf/truncate.c:249!
...

Fix the problem by bailing out cleanly in case of IO error.

CC: stable@vger.kernel.org
Reported-by: jean-luc malet <jeanluc.malet@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
---
 fs/udf/truncate.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c
index b647f0bd150c..94220ba85628 100644
--- a/fs/udf/truncate.c
+++ b/fs/udf/truncate.c
@@ -260,6 +260,9 @@ void udf_truncate_extents(struct inode *inode)
 			epos.block = eloc;
 			epos.bh = udf_tread(sb,
 					udf_get_lb_pblock(sb, &eloc, 0));
+			/* Error reading indirect block? */
+			if (!epos.bh)
+				return;
 			if (elen)
 				indirect_ext_len =
 					(elen + sb->s_blocksize - 1) >>
-- 
2.39.5