udf: Fix crash on IO error during truncate

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>

diff --git a/fs/udf/truncate.c b/fs/udf/truncate.c
index b647f0b..94220ba 100644 (file)
--- 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) >>