linux-kernel - Re: [External] : [PATCH] ocfs2: retire ocfs2_drop_inode() and I_WILL

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Message-ID: <CAGudoHHT=P_UyZZpx5tBRHPE+irh1b7PxFXZAHjdHNLcEWOxAQ@mail.gmail.com>
Date: Thu, 4 Sep 2025 18:22:04 +0200
From: Mateusz Guzik <mjguzik@...il.com>
To: Mark Tinguely <mark.tinguely@...cle.com>
Cc: ocfs2-devel@...ts.linux.dev, viro@...iv.linux.org.uk, jack@...e.cz, 
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	josef@...icpanda.com, joseph.qi@...ux.alibaba.com, jlbec@...lplan.org, 
	mark@...heh.com, brauner@...nel.org, willy@...radead.org, david@...morbit.com
Subject: Re: [External] : [PATCH] ocfs2: retire ocfs2_drop_inode() and
 I_WILL_FREE usage

On Thu, Sep 4, 2025 at 6:15 PM Mark Tinguely <mark.tinguely@...cle.com> wrote:
>
> On 9/4/25 10:42 AM, Mateusz Guzik wrote:
> > This postpones the writeout to ocfs2_evict_inode(), which I'm told is
> > fine (tm).
> >
> > The intent is to retire the I_WILL_FREE flag.
> >
> > Signed-off-by: Mateusz Guzik <mjguzik@...il.com>
> > ---
> >
> > ACHTUNG: only compile-time tested. Need an ocfs2 person to ack it.
> >
> > btw grep shows comments referencing ocfs2_drop_inode() which are already
> > stale on the stock kernel, I opted to not touch them.
> >
> > This ties into an effort to remove the I_WILL_FREE flag, unblocking
> > other work. If accepted would be probably best taken through vfs
> > branches with said work, see https://urldefense.com/v3/__https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git/log/?h=vfs-6.18.inode.refcount.preliminaries__;!!ACWV5N9M2RV99hQ!OLwk8DVo7uvC-Pd6XVTiUCgP6MUDMKBMEyuV27h_yPGXOjaq078-kMdC9ILFoYQh-4WX93yb0nMfBDFFY_0$
> >
> >   fs/ocfs2/inode.c       | 23 ++---------------------
> >   fs/ocfs2/inode.h       |  1 -
> >   fs/ocfs2/ocfs2_trace.h |  2 --
> >   fs/ocfs2/super.c       |  2 +-
> >   4 files changed, 3 insertions(+), 25 deletions(-)
> >
> > diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
> > index 6c4f78f473fb..5f4a2cbc505d 100644
> > --- a/fs/ocfs2/inode.c
> > +++ b/fs/ocfs2/inode.c
> > @@ -1290,6 +1290,8 @@ static void ocfs2_clear_inode(struct inode *inode)
> >
> >   void ocfs2_evict_inode(struct inode *inode)
> >   {
> > +     write_inode_now(inode, 1);
> > +
> >       if (!inode->i_nlink ||
> >           (OCFS2_I(inode)->ip_flags & OCFS2_INODE_MAYBE_ORPHANED)) {
> >               ocfs2_delete_inode(inode);
> > @@ -1299,27 +1301,6 @@ void ocfs2_evict_inode(struct inode *inode)
> >       ocfs2_clear_inode(inode);
> >   }
> >
> > -/* Called under inode_lock, with no more references on the
> > - * struct inode, so it's safe here to check the flags field
> > - * and to manipulate i_nlink without any other locks. */
> > -int ocfs2_drop_inode(struct inode *inode)
> > -{
> > -     struct ocfs2_inode_info *oi = OCFS2_I(inode);
> > -
> > -     trace_ocfs2_drop_inode((unsigned long long)oi->ip_blkno,
> > -                             inode->i_nlink, oi->ip_flags);
> > -
> > -     assert_spin_locked(&inode->i_lock);
> > -     inode->i_state |= I_WILL_FREE;
> > -     spin_unlock(&inode->i_lock);
> > -     write_inode_now(inode, 1);
> > -     spin_lock(&inode->i_lock);
> > -     WARN_ON(inode->i_state & I_NEW);
> > -     inode->i_state &= ~I_WILL_FREE;
> > -
> > -     return 1;
> > -}
> > -
> >   /*
> >    * This is called from our getattr.
> >    */
> > diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
> > index accf03d4765e..07bd838e7843 100644
> > --- a/fs/ocfs2/inode.h
> > +++ b/fs/ocfs2/inode.h
> > @@ -116,7 +116,6 @@ static inline struct ocfs2_caching_info *INODE_CACHE(struct inode *inode)
> >   }
> >
> >   void ocfs2_evict_inode(struct inode *inode);
> > -int ocfs2_drop_inode(struct inode *inode);
> >
> >   /* Flags for ocfs2_iget() */
> >   #define OCFS2_FI_FLAG_SYSFILE               0x1
> > diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h
> > index 54ed1495de9a..4b32fb5658ad 100644
> > --- a/fs/ocfs2/ocfs2_trace.h
> > +++ b/fs/ocfs2/ocfs2_trace.h
> > @@ -1569,8 +1569,6 @@ DEFINE_OCFS2_ULL_ULL_UINT_EVENT(ocfs2_delete_inode);
> >
> >   DEFINE_OCFS2_ULL_UINT_EVENT(ocfs2_clear_inode);
> >
> > -DEFINE_OCFS2_ULL_UINT_UINT_EVENT(ocfs2_drop_inode);
> > -
> >   TRACE_EVENT(ocfs2_inode_revalidate,
> >       TP_PROTO(void *inode, unsigned long long ino,
> >                unsigned int flags),
> > diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> > index 53daa4482406..e4b0d25f4869 100644
> > --- a/fs/ocfs2/super.c
> > +++ b/fs/ocfs2/super.c
> > @@ -129,7 +129,7 @@ static const struct super_operations ocfs2_sops = {
> >       .statfs         = ocfs2_statfs,
> >       .alloc_inode    = ocfs2_alloc_inode,
> >       .free_inode     = ocfs2_free_inode,
> > -     .drop_inode     = ocfs2_drop_inode,
> > +     .drop_inode     = generic_delete_inode,
> >       .evict_inode    = ocfs2_evict_inode,
> >       .sync_fs        = ocfs2_sync_fs,
> >       .put_super      = ocfs2_put_super,
>
>
> I agree, fileystems should not use I_FREEING/I_WILL_FREE.
> Doing the sync write_inode_now() should be fine in ocfs_evict_inode().
>
> Question is ocfs_drop_inode. In commit 513e2dae9422:
>   ocfs2: flush inode data to disk and free inode when i_count becomes zero
> the return of 1 drops immediate to fix a memory caching issue.
> Shouldn't .drop_inode() still return 1?

generic_delete_inode is a stub doing just that.

-- 
Mateusz Guzik <mjguzik gmail.com>