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Message-ID: <rvavp2omizs6e3qf6xpjpycf6norhfhnkrle4fq4632atgar5v@dghmwbctf2mm>
Date: Mon, 8 Sep 2025 12:23:55 +0200
From: Jan Kara <jack@...e.cz>
To: Joseph Qi <joseph.qi@...ux.alibaba.com>
Cc: Mateusz Guzik <mjguzik@...il.com>,
Mark Tinguely <mark.tinguely@...cle.com>, 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, 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 Mon 08-09-25 09:51:36, Joseph Qi wrote:
> On 2025/9/5 00:22, Mateusz Guzik wrote:
> > 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.
> >
> In case of "drop = 0", it may return directly without calling evict().
> This seems break the expectation of commit 513e2dae9422.
generic_delete_inode() always returns 1 so evict() will be called.
ocfs2_drop_inode() always returns 1 as well after 513e2dae9422. So I'm not
sure which case of "drop = 0" do you see...
Honza
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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