On Thu 09-07-20 14:36:55, Lukas Czerner wrote:
> On Thu, Jul 09, 2020 at 11:58:54AM +0200, Jan Kara wrote:
> > A customer has reported a BUG_ON in ext4_clear_journal_err() hitting
> > during an LTP testing. Either this has been caused by a test setup
> > issue where the filesystem was being overwritten while LTP was mounting
> > it or the journal replay has overwritten the superblock with invalid
> > data. In either case it is preferable we don't take the machine down
> > with a BUG_ON. So handle the situation of unexpectedly missing
> > has_journal feature more gracefully by a WARN_ON_ONCE and bailing out
> > with error.
> >
> > Signed-off-by: Jan Kara <jack@xxxxxxx>
> > ---
> > fs/ext4/super.c | 35 ++++++++++++++++++++++++-----------
> > 1 file changed, 24 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > index 330957ed1f05..d8b7222cb86c 100644
> > --- a/fs/ext4/super.c
> > +++ b/fs/ext4/super.c
> > @@ -68,8 +68,8 @@ static int ext4_show_options(struct seq_file *seq, struct dentry *root);
> > static int ext4_commit_super(struct super_block *sb, int sync);
> > static void ext4_mark_recovery_complete(struct super_block *sb,
> > struct ext4_super_block *es);
> > -static void ext4_clear_journal_err(struct super_block *sb,
> > - struct ext4_super_block *es);
> > +static int ext4_clear_journal_err(struct super_block *sb,
> > + struct ext4_super_block *es);
> > static int ext4_sync_fs(struct super_block *sb, int wait);
> > static int ext4_remount(struct super_block *sb, int *flags, char *data);
> > static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
> > @@ -4956,7 +4956,8 @@ static journal_t *ext4_get_journal(struct super_block *sb,
> > struct inode *journal_inode;
> > journal_t *journal;
> >
> > - BUG_ON(!ext4_has_feature_journal(sb));
> > + if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
> > + return NULL;
> >
> > journal_inode = ext4_get_journal_inode(sb, journal_inum);
> > if (!journal_inode)
> > @@ -4986,7 +4987,8 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb,
> > struct ext4_super_block *es;
> > struct block_device *bdev;
> >
> > - BUG_ON(!ext4_has_feature_journal(sb));
> > + if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
> > + return NULL;
> >
> > bdev = ext4_blkdev_get(j_dev, sb);
> > if (bdev == NULL)
> > @@ -5078,7 +5080,8 @@ static int ext4_load_journal(struct super_block *sb,
> > int err = 0;
> > int really_read_only;
> >
> > - BUG_ON(!ext4_has_feature_journal(sb));
> > + if (WARN_ON_ONCE(!ext4_has_feature_journal(sb)))
> > + return -EFSCORRUPTED;
> >
> > if (journal_devnum &&
> > journal_devnum != le32_to_cpu(es->s_journal_dev)) {
> > @@ -5148,7 +5151,12 @@ static int ext4_load_journal(struct super_block *sb,
> > }
> >
> > EXT4_SB(sb)->s_journal = journal;
> > - ext4_clear_journal_err(sb, es);
> > + err = ext4_clear_journal_err(sb, es);
> > + if (err) {
> > + EXT4_SB(sb)->s_journal = NULL;
> > + jbd2_journal_destroy(journal);
> > + return err;
> > + }
> >
> > if (!really_read_only && journal_devnum &&
> > journal_devnum != le32_to_cpu(es->s_journal_dev)) {
> > @@ -5250,7 +5258,7 @@ static void ext4_mark_recovery_complete(struct super_block *sb,
> > journal_t *journal = EXT4_SB(sb)->s_journal;
> >
> > if (!ext4_has_feature_journal(sb)) {
> > - BUG_ON(journal != NULL);
> > + WARN_ON_ONCE(journal != NULL);
Hi Lukas!
> If this ever happens we will hapily continue with fs operation after
> mount, or remount (remount is ro, so that is probably ok ?) without
> journal feature, but with s_journal set ? I am not quite sure what the
> consequences might be, are you sure this is ok ?
Hum, you're right we should probably fail the mount... In fact looking into
this now, we should probably also handle this situation with ext4_error() so
that filesystem gets marked as corrupted and all that. Thanks for feedback.
I'll rework the patch.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
