Re: [PATCH v3 1/2] ext4: commit super block if fs record error when journal record without error

[yebin (H)]

On 2023/2/16 17:17, Baokun Li wrote:
> On 2023/2/16 15:44, yebin (H) wrote:
> > On 2023/2/16 15:17, Baokun Li wrote:
> > > On 2023/2/14 10:29, Ye Bin wrote:
> > > > From: Ye Bin <yebin10@xxxxxxxxxx>
> > > >
> > > > Now, 'es->s_state' maybe covered by recover journal. And journal errno
> > > > maybe not recorded in journal sb as IO error. ext4_update_super() only
> > > > update error information when 'sbi->s_add_error_count' large than 
> > > > zero.
> > > > Then 'EXT4_ERROR_FS' flag maybe lost.
> > > > To solve above issue commit error information after recover journal.
> > > >
> > > > Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
> > > > ---
> > > >   fs/ext4/super.c | 12 ++++++++++++
> > > >   1 file changed, 12 insertions(+)
> > > >
> > > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > > > index dc3907dff13a..b94754ba8556 100644
> > > > --- a/fs/ext4/super.c
> > > > +++ b/fs/ext4/super.c
> > > > @@ -5932,6 +5932,18 @@ static int ext4_load_journal(struct 
> > > > super_block *sb,
> > > >           goto err_out;
> > > >       }
> > > >   +    if (unlikely(es->s_error_count && 
> > > > !jbd2_journal_errno(journal) &&
> > > > +             !(le16_to_cpu(es->s_state) & EXT4_ERROR_FS))) {
> > > > +        EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
> > > > +        es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
> > > > +        err = ext4_commit_super(sb);
> > > > +        if (err) {
> > > > +            ext4_msg(sb, KERN_ERR,
> > > > +                 "Failed to commit error information, please 
> > > > repair fs force!");
> > > > +            goto err_out;
> > > > +        }
> > > > +    }
> > > > +
> > > >       EXT4_SB(sb)->s_journal = journal;
> > > >       err = ext4_clear_journal_err(sb, es);
> > > >       if (err) {
> > > I think we don't need such a complicated judgment, after the journal 
> > > replay and saving the error info,
> > > if there is EXT4_ERROR_FS flag in ext4_sb_info->s_mount_state, just 
> > > add this flag directly to es->s_state.
> > > This way the EXT4_ERROR_FS flag and the error message will be 
> > > written to disk the next time
> >
> > Thanks for your suggestion. There are two reasons for this:
> > 1. We want to write the error mark to the disk as soon as possible.
> > 2. Here we deal with the case where there is no error mark bit but 
> > there is an error record.
> > In this case, the file system should be marked with an error and the 
> > user should be prompted.
> The EXT4_ERROR_FS flag is always written to disk at the same time as 
> the error info,
> except when the journal is replayed. During journal replay the error 
> info is additionally
> copied to disk first, and the EXT4_ERROR_FS flag in the sbi is not 
> written to disk until
> the ext4_put_super() is called. It is only when a failure occurs 
> during this time that
> there is an error info but no EXT4_ERROR_FS flag. So we just need to 
> make sure that
> the EXT4_ERROR_FS flag is also written to disk at the same time as the 
> error info
> after the journal replay.
The situation you said is based on the situation after the repair. What 
about the existing
image with such inconsistency?
> > > ext4_commit_super() is executed. The code change is as follows:
> > >
> > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> > > index 260c1b3e3ef2..341b11c589b3 100644
> > > --- a/fs/ext4/super.c
> > > +++ b/fs/ext4/super.c
> > > @@ -5935,6 +5935,7 @@ static int ext4_load_journal(struct 
> > > super_block *sb,
> > >                         memcpy(((char *) es) + EXT4_S_ERR_START,
> > >                                save, EXT4_S_ERR_LEN);
> > >                 kfree(save);
> > > +               es->s_state |= 
> > > cpu_to_le16(EXT4_SB(sb)->s_mount_state & EXT4_ERROR_FS);
> > >         }
> > >
> > >         if (err) {