Looks good!
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
On Wed, May 29, 2024 at 2:50 AM Jan Kara <jack@xxxxxxx> wrote:
>
> On Wed 29-05-24 10:20:29, Luis Henriques (SUSE) wrote:
> > When a full journal commit is on-going, any fast commit has to be enqueued
> > into a different queue: FC_Q_STAGING instead of FC_Q_MAIN. This enqueueing
> > is done only once, i.e. if an inode is already queued in a previous fast
> > commit entry it won't be enqueued again. However, if a full commit starts
> > _after_ the inode is enqueued into FC_Q_MAIN, the next fast commit needs to
> > be done into FC_Q_STAGING. And this is not being done in function
> > ext4_fc_track_template().
> >
> > This patch fixes the issue by re-enqueuing an inode into the STAGING queue
> > during the fast commit clean-up callback if it has a tid (i_sync_tid)
> > greater than the one being handled. The STAGING queue will then be spliced
> > back into MAIN.
> >
> > This bug was found using fstest generic/047. This test creates several 32k
> > bytes files, sync'ing each of them after it's creation, and then shutting
> > down the filesystem. Some data may be loss in this operation; for example a
> > file may have it's size truncated to zero.
> >
> > Signed-off-by: Luis Henriques (SUSE) <luis.henriques@xxxxxxxxx>
>
> Looks good to me! Feel free to add:
>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
>
> Just a typo correction below.
>
> > diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
> > index 87c009e0c59a..088bd509b116 100644
> > --- a/fs/ext4/fast_commit.c
> > +++ b/fs/ext4/fast_commit.c
> > @@ -1282,8 +1282,17 @@ static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
> > list_del_init(&iter->i_fc_list);
> > ext4_clear_inode_state(&iter->vfs_inode,
> > EXT4_STATE_FC_COMMITTING);
> > - if (iter->i_sync_tid <= tid)
> > + if (iter->i_sync_tid <= tid) {
> > ext4_fc_reset_inode(&iter->vfs_inode);
> > + } else {
> > + /*
> > + * re-enqueue inode into STAGING, which later will be
> > + * splice back into MAIN
> ^^^ spliced
>
> > + */
> > + list_add_tail(&EXT4_I(&iter->vfs_inode)->i_fc_list,
> > + &sbi->s_fc_q[FC_Q_STAGING]);
> > + }
> > +
>
> Honza
> --
> Jan Kara <jack@xxxxxxxx>
> SUSE Labs, CR
