linux-kernel - Re: [PATCH 1/2] ocfs2: Add ocfs2_emergency

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Message-ID: <aSlmFFFxQfbnaRWV@eray-kasa>
Date: Fri, 28 Nov 2025 12:06:28 +0300
From: Ahmet Eray Karadag <eraykrdg1@...il.com>
To: Heming Zhao <heming.zhao@...e.com>
Cc: mark@...heh.com, jlbec@...lplan.org, joseph.qi@...ux.alibaba.com,
	ocfs2-devel@...ts.linux.dev, linux-kernel@...r.kernel.org,
	david.hunter.linux@...il.com, skhan@...uxfoundation.org,
	Albin Babu Varghese <albinbabuvarghese20@...il.com>
Subject: Re: [PATCH 1/2] ocfs2: Add ocfs2_emergency_state helper and apply to
 setattr

On Tue, Nov 25, 2025 at 10:58:32AM +0800, Heming Zhao wrote:
> On Tue, Nov 18, 2025 at 03:26:44AM +0300, Ahmet Eray Karadag wrote:
> > To centralize error checking, follow the pattern of other filesystems
> > like ext4 (which uses `ext4_emergency_state()`), and prepare for
> > future enhancements, this patch introduces a new helper function:
> > `ocfs2_emergency_state()`.
> > 
> > The purpose of this helper is to provide a single, unified location
> > for checking all filesystem-level emergency conditions. In this
> > initial implementation, the function only checks for the existing
> > hard and soft read-only modes, returning -EROFS if either is set.
> > 
> > This provides a foundation where future checks (e.g., for fatal error
> > states returning -EIO, or shutdown states) can be easily added in
> > one place.
> > 
> > This patch also adds this new check to the beginning of
> > `ocfs2_setattr()`. This ensures that operations like `ftruncate`
> > (which triggered the original BUG) fail-fast with -EROFS when the
> > filesystem is already in a read-only state.
> > 
> > Suggested-by: Heming Zhao <heming.zhao@...e.com>
> > Co-developed-by: Albin Babu Varghese <albinbabuvarghese20@...il.com>
> > Signed-off-by: Albin Babu Varghese <albinbabuvarghese20@...il.com>
> > Signed-off-by: Ahmet Eray Karadag <eraykrdg1@...il.com>
> > ---
> >  fs/ocfs2/file.c  | 6 ++++++
> >  fs/ocfs2/ocfs2.h | 8 ++++++++
> >  2 files changed, 14 insertions(+)
> > 
> > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> > index 21d797ccccd0..03a98985ac92 100644
> > --- a/fs/ocfs2/file.c
> > +++ b/fs/ocfs2/file.c
> > @@ -1137,6 +1137,12 @@ int ocfs2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> >  					from_kgid(&init_user_ns, attr->ia_gid) : 0);
> >  
> >  	/* ensuring we don't even attempt to truncate a symlink */
> > +	status = ocfs2_emergency_state(osb);
> > +	if (status < 0) {
> > +		mlog_errno(status);
> > +		goto bail;
> > +	}
> > +
> 
> I prefer the ext4_emerency_state() style, using "if (unlikely(status))" here.
> 
> >  	if (S_ISLNK(inode->i_mode))
> >  		attr->ia_valid &= ~ATTR_SIZE;
> >  
> > diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> > index 6aaa94c554c1..2ac16632dd19 100644
> > --- a/fs/ocfs2/ocfs2.h
> > +++ b/fs/ocfs2/ocfs2.h
> > @@ -680,6 +680,14 @@ static inline int ocfs2_is_soft_readonly(struct ocfs2_super *osb)
> >  	return ret;
> >  }
> >  
> > +static inline int ocfs2_emergency_state(struct ocfs2_super *osb)
> > +{
> > +	if (ocfs2_is_soft_readonly(osb) || ocfs2_is_hard_readonly(osb)) {
> > +		return -EROFS;
> > +	}
> > +	return 0;
> > +}
> > +
> 
> calling ocfs2_is_[soft|hard]_readonly() is a little expensive because it
> involves acquiring the spinlock osb->osb_lock twice. In my view, we could
> introduce a new function, such as ocfs2_is_readonly():
In ext4, the helper functions check read-only flags without acquiring a lock.
Would it be problematic to do the same in ocfs2?
> 
> ```
> static inline int ocfs2_is_readonly(struct ocfs2_super *osb)
> {
>         int ret;
> 
>         spin_lock(&osb->osb_lock);
>         ret = osb->osb_flags & (OCFS2_OSB_SOFT_RO | OCFS2_OSB_HARD_RO);
>         spin_unlock(&osb->osb_lock);
> 
>         return ret
> }
> ```
> 
> Thanks,
> Heming
> 
> >  static inline int ocfs2_clusterinfo_valid(struct ocfs2_super *osb)
> >  {
> >  	return (osb->s_feature_incompat &
> > -- 
> > 2.43.0
> > 
I agree with the other comments. We will send v2.