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
