linux-kernel - Re: [PATCH 12/12] nfsd: discard fh_locked flag and fh_lock/fh

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Date:   Fri, 24 Jun 2022 14:43:39 +0000
From:   Chuck Lever III <chuck.lever@...cle.com>
To:     Neil Brown <neilb@...e.de>
CC:     Al Viro <viro@...iv.linux.org.uk>, Daire Byrne <daire@...g.com>,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Linux NFS Mailing List <linux-nfs@...r.kernel.org>,
        "linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 12/12] nfsd: discard fh_locked flag and fh_lock/fh_unlock



> On Jun 13, 2022, at 7:18 PM, NeilBrown <neilb@...e.de> wrote:
> 
> fh_lock() and fh_unlock() are no longer used, so discard them.
> They are the only real users of ->fh_locked, so discard that too.
> 
> Signed-off-by: NeilBrown <neilb@...e.de>

Reviewed-by: Chuck Lever <chuck.lever@...cle.com>


> ---
> fs/nfsd/nfsfh.c |    2 +-
> fs/nfsd/nfsfh.h |   48 ++++--------------------------------------------
> fs/nfsd/vfs.c   |    4 ----
> 3 files changed, 5 insertions(+), 49 deletions(-)
> 
> diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
> index ae270e4f921f..a3dbe9f34c0e 100644
> --- a/fs/nfsd/nfsfh.c
> +++ b/fs/nfsd/nfsfh.c
> @@ -548,7 +548,7 @@ fh_compose(struct svc_fh *fhp, struct svc_export *exp, struct dentry *dentry,
> 	if (ref_fh == fhp)
> 		fh_put(ref_fh);
> 
> -	if (fhp->fh_locked || fhp->fh_dentry) {
> +	if (fhp->fh_dentry) {
> 		printk(KERN_ERR "fh_compose: fh %pd2 not initialized!\n",
> 		       dentry);
> 	}
> diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
> index c5061cdb1016..559912b1d794 100644
> --- a/fs/nfsd/nfsfh.h
> +++ b/fs/nfsd/nfsfh.h
> @@ -81,7 +81,6 @@ typedef struct svc_fh {
> 	struct dentry *		fh_dentry;	/* validated dentry */
> 	struct svc_export *	fh_export;	/* export pointer */
> 
> -	bool			fh_locked;	/* inode locked by us */
> 	bool			fh_want_write;	/* remount protection taken */
> 	bool			fh_no_wcc;	/* no wcc data needed */
> 	bool			fh_no_atomic_attr;
> @@ -93,7 +92,7 @@ typedef struct svc_fh {
> 	bool			fh_post_saved;	/* post-op attrs saved */
> 	bool			fh_pre_saved;	/* pre-op attrs saved */
> 
> -	/* Pre-op attributes saved during fh_lock */
> +	/* Pre-op attributes saved when inode exclusively locked */
> 	__u64			fh_pre_size;	/* size before operation */
> 	struct timespec64	fh_pre_mtime;	/* mtime before oper */
> 	struct timespec64	fh_pre_ctime;	/* ctime before oper */
> @@ -103,7 +102,7 @@ typedef struct svc_fh {
> 	 */
> 	u64			fh_pre_change;
> 
> -	/* Post-op attributes saved in fh_unlock */
> +	/* Post-op attributes saved in fh_fill_post_attrs() */
> 	struct kstat		fh_post_attr;	/* full attrs after operation */
> 	u64			fh_post_change; /* nfsv4 change; see above */
> } svc_fh;
> @@ -223,8 +222,8 @@ void	fh_put(struct svc_fh *);
> static __inline__ struct svc_fh *
> fh_copy(struct svc_fh *dst, struct svc_fh *src)
> {
> -	WARN_ON(src->fh_dentry || src->fh_locked);
> -			
> +	WARN_ON(src->fh_dentry);
> +
> 	*dst = *src;
> 	return dst;
> }
> @@ -323,43 +322,4 @@ static inline u64 nfsd4_change_attribute(struct kstat *stat,
> extern void fh_fill_pre_attrs(struct svc_fh *fhp, bool atomic);
> extern void fh_fill_post_attrs(struct svc_fh *fhp);
> 
> -static inline void
> -fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
> -{
> -	struct dentry	*dentry = fhp->fh_dentry;
> -	struct inode	*inode;
> -
> -	BUG_ON(!dentry);
> -
> -	if (fhp->fh_locked) {
> -		printk(KERN_WARNING "fh_lock: %pd2 already locked!\n",
> -			dentry);
> -		return;
> -	}
> -
> -	inode = d_inode(dentry);
> -	inode_lock_nested(inode, subclass);
> -	fh_fill_pre_attrs(fhp, true);
> -	fhp->fh_locked = true;
> -}
> -
> -static inline void
> -fh_lock(struct svc_fh *fhp)
> -{
> -	fh_lock_nested(fhp, I_MUTEX_NORMAL);
> -}
> -
> -/*
> - * Unlock a file handle/inode
> - */
> -static inline void
> -fh_unlock(struct svc_fh *fhp)
> -{
> -	if (fhp->fh_locked) {
> -		fh_fill_post_attrs(fhp);
> -		inode_unlock(d_inode(fhp->fh_dentry));
> -		fhp->fh_locked = false;
> -	}
> -}
> -
> #endif /* _LINUX_NFSD_NFSFH_H */
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index f2f4868618bb..0e07b19a0289 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1623,14 +1623,11 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> 		goto out;
> 	}
> 
> -	/* cannot use fh_lock as we need deadlock protective ordering
> -	 * so do it by hand */
> 	trap = lock_rename_lookup_one(tdentry, fdentry, &ndentry, &odentry,
> 				      tname, tlen, fname, flen, 0, 0, &wq);
> 	host_err = PTR_ERR(trap);
> 	if (IS_ERR(trap))
> 		goto out_nfserr;
> -	ffhp->fh_locked = tfhp->fh_locked = true;
> 	fh_fill_pre_attrs(ffhp, (ndentry->d_flags & DCACHE_PAR_UPDATE) == 0);
> 	fh_fill_pre_attrs(tfhp, (ndentry->d_flags & DCACHE_PAR_UPDATE) == 0);
> 
> @@ -1678,7 +1675,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> 	}
>  out_unlock:
> 	unlock_rename_lookup(tdentry, fdentry, ndentry, odentry);
> -	ffhp->fh_locked = tfhp->fh_locked = false;
>  out_nfserr:
> 	err = nfserrno(host_err);
> 	fh_drop_write(ffhp);
> 
> 

--
Chuck Lever