Re: [PATCH] gfs2: stop logd and quotad before kill_sb log flush

Hi,

Jiaming Zhang <[email protected]> =E4=BA=8E2026=E5=B9=B47=E6=9C=8810=E6=
=97=A5=E5=91=A8=E4=BA=94 17:29=E5=86=99=E9=81=93=EF=BC=9A
>
> gfs2_kill_sb() issues a synchronous log flush before stopping the gfs2_lo=
gd and
> gfs2_quotad kthreads. Given a corrupted filesystem image, that flush can =
spend a
> long time while holding sd_log_flush_lock. Since the background threads a=
re
> still alive at that point, gfs2_logd can be woken and block on sd_log_flu=
sh_lock
> in gfs2_logd(), and gfs2_quotad can block on the same lock through
> gfs2_statfs_sync() -> __gfs2_trans_begin(). The threads can then remain i=
n
> uninterruptible sleep long enough to trigger the hung task.
>
> Stop the background threads before the kill_sb log flush. gfs2_destroy_th=
reads()
> waits for both kthreads to exit via kthread_stop_put(), so after it retur=
ns
> there is no live logd or quotad thread that can wait behind sd_log_flush_=
lock.
>
> Closes: https://lore.kernel.org/lkml/CANypQFasb8voDrg=3DO9xJikYHdRFeupb5V=
[email protected]/
> Assisted-by: Codex:gpt-5.5-xhigh
> Signed-off-by: Jiaming Zhang <[email protected]>
> ---
>  fs/gfs2/ops_fstype.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
> index 9b9e70f14d25..d087845a75d6 100644
> --- a/fs/gfs2/ops_fstype.c
> +++ b/fs/gfs2/ops_fstype.c
> @@ -1776,6 +1776,8 @@ static void gfs2_kill_sb(struct super_block *sb)
>                 return;
>         }
>
> +       gfs2_destroy_threads(sdp);
> +
>         gfs2_log_flush(sdp, NULL, GFS2_LOG_HEAD_FLUSH_SYNC | GFS2_LFC_KIL=
L_SB);
>         dput(sdp->sd_root_dir);
>         dput(sdp->sd_master_dir);
> --
> 2.43.0
>

Friendly ping. Please let me know if there's anything you'd like me to chan=
ge.

Best Regards,
Jiaming Zhang