Re: [PATCH] xfs: restore nofs context unconditionally in xfs_trans_roll

[Zhou, Yun]

On 7/13/26 17:09, Christoph Hellwig wrote:
> On Mon, Jul 13, 2026 at 11:55:05AM +0800, Yun Zhou wrote:
> > diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
> > index 7bfbd9f6f0df..1b36cf12d4e3 100644
> > --- a/fs/xfs/xfs_trans.c
> > +++ b/fs/xfs/xfs_trans.c
> > @@ -1029,6 +1029,15 @@ xfs_trans_roll(
> >         * duplicate transaction that gets returned.
> >         */
> >        error = __xfs_trans_commit(tp, true);
> > +
> > +     tp = *tpp;
> > +     /*
> > +      * __xfs_trans_commit cleared the NOFS flag by calling into
> > +      * xfs_trans_free.  Set it again here before doing memory
> > +      * allocations.
> > +      */
> > +     xfs_trans_set_context(tp);
>
> The tp assignment above now returns the incorrect transaction when
> __xfs_trans_commit fails, so you can't do this.
>
> Otherwise yes, this call should move up.  I don't really see how
> it fixes the syzbot report, though.

Thank you very much for your reply. The tp here is a local variable only 
used for convenience within the function. The caller always gets the new 
transaction through *tpp, which was set by xfs_trans_dup() before the 
commit call. Moving tp = *tpp before the error check doesn't change what 
the caller sees - *tpp still points to the new (dup'd) transaction 
regardless.

If I have overlooked any edge cases, please point them out.

BR,
Yun