nilfs2: replace WARN_ONs by nilfs_error for checkpoint acquisition failure

BugLink: https://bugs.launchpad.net/bugs/1995638
commit 723ac751208f6d6540191689cfbf6c77135a7a1b upstream.

If creation or finalization of a checkpoint fails due to anomalies in the
checkpoint metadata on disk, a kernel warning is generated.

This patch replaces the WARN_ONs by nilfs_error, so that a kernel, booted
with panic_on_warn, does not panic.  A nilfs_error is appropriate here to
handle the abnormal filesystem condition.

This also replaces the detected error codes with an I/O error so that
neither of the internal error codes is returned to callers.

Link: https://lkml.kernel.org/r/20220929123330.19658-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+fbb3e0b24e8dae5a16ee@syzkaller.appspotmail.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index a353ca3fc580a6d54e715791037dd759d1ce79e0..96c5cab5c8ae57d7b5c23e62bc8de5db42cefd1b 100644 (file)
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -875,9 +875,11 @@ static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
                nilfs_mdt_mark_dirty(nilfs->ns_cpfile);
                nilfs_cpfile_put_checkpoint(
                        nilfs->ns_cpfile, nilfs->ns_cno, bh_cp);
-       } else
-               WARN_ON(err == -EINVAL || err == -ENOENT);
-
+       } else if (err == -EINVAL || err == -ENOENT) {
+               nilfs_error(sci->sc_super,
+                           "checkpoint creation failed due to metadata corruption.");
+               err = -EIO;
+       }
        return err;
 }
 
@@ -891,7 +893,11 @@ static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
        err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, nilfs->ns_cno, 0,
                                          &raw_cp, &bh_cp);
        if (unlikely(err)) {
-               WARN_ON(err == -EINVAL || err == -ENOENT);
+               if (err == -EINVAL || err == -ENOENT) {
+                       nilfs_error(sci->sc_super,
+                                   "checkpoint finalization failed due to metadata corruption.");
+                       err = -EIO;
+               }
                goto failed_ibh;
        }
        raw_cp->cp_snapshot_list.ssl_next = 0;