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

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Message-ID: <f3671198-5231-41cf-b0bc-d1280992947a@oracle.com>
Date: Thu, 4 Sep 2025 11:15:18 -0500
From: Mark Tinguely <mark.tinguely@...cle.com>
To: Mateusz Guzik <mjguzik@...il.com>, ocfs2-devel@...ts.linux.dev
Cc: 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 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?

Mark Tinguely