Date:   Tue, 28 Jun 2022 22:35:54 +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 08/12] nfsd: allow parallel creates from nfsd



> On Jun 13, 2022, at 7:18 PM, NeilBrown <neilb@...e.de> wrote:
> 
> Rather than getting write access, locking the directory, and performing
> a lookup, use
>  filename_create_one_len() for create, or
>  lookup_hash_update_len() for delete
> which combines all these steps and handles shared locking for concurrent
> updates where appropriate.
> 
> As we don't use fh_lock() we need to call fh_fill_pre_attrs()
> explicitly.  However if we only get a shared lock, then the pre/post
> attributes won't be atomic, so we need to ensure that fh know that,
> and doesn't try to encode wcc attrs either.
> 
> Note that there is only one filesystem that allows shared locks for
> create/unlink and that is NFS (for re-export).  NFS does support atomic
> pre/post attributes, so there is no loss in not providing them.
> 
> When some other filesystem supports concurrent updates, we might need to
> consider if the pre/post attributes are more important than the
> parallelism.
> 
> Signed-off-by: NeilBrown <neilb@...e.de>
> ---
> fs/nfsd/nfs3proc.c |   31 +++++-------
> fs/nfsd/nfs4proc.c |   32 +++++-------
> fs/nfsd/nfsfh.c    |    7 ++-
> fs/nfsd/nfsfh.h    |    4 +-
> fs/nfsd/nfsproc.c  |   29 +++++------
> fs/nfsd/vfs.c      |  134 +++++++++++++++++++++++-----------------------------
> 6 files changed, 105 insertions(+), 132 deletions(-)
> 
> diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
> index 981a3a7a6e16..0fdbb9504a87 100644
> --- a/fs/nfsd/nfs3proc.c
> +++ b/fs/nfsd/nfs3proc.c
> @@ -231,12 +231,14 @@ static __be32
> nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 		  struct svc_fh *resfhp, struct nfsd3_createargs *argp)
> {
> +	struct path path;
> 	struct iattr *iap = &argp->attrs;
> -	struct dentry *parent, *child;
> +	struct dentry *child;
> 	__u32 v_mtime, v_atime;
> 	struct inode *inode;
> 	__be32 status;
> 	int host_err;
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	if (isdotent(argp->name, argp->len))
> 		return nfserr_exist;
> @@ -247,20 +249,15 @@ nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 	if (status != nfs_ok)
> 		return status;
> 
> -	parent = fhp->fh_dentry;
> -	inode = d_inode(parent);
> +	path.dentry = fhp->fh_dentry;
> +	path.mnt = fhp->fh_export->ex_path.mnt;
> +	inode = d_inode(path.dentry);
> 
> -	host_err = fh_want_write(fhp);
> -	if (host_err)
> -		return nfserrno(host_err);
> +	child = filename_create_one_len(argp->name, argp->len,
> +					&path, 0, &wq);
> 
> -	fh_lock_nested(fhp, I_MUTEX_PARENT);
> -
> -	child = lookup_one_len(argp->name, parent, argp->len);
> -	if (IS_ERR(child)) {
> -		status = nfserrno(PTR_ERR(child));
> -		goto out;
> -	}
> +	if (IS_ERR(child))
> +		return nfserrno(PTR_ERR(child));
> 
> 	if (d_really_is_negative(child)) {
> 		status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
> @@ -311,6 +308,7 @@ nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 
> 	if (!IS_POSIXACL(inode))
> 		iap->ia_mode &= ~current_umask();
> +	fh_fill_pre_attrs(fhp, (child->d_flags & DCACHE_PAR_UPDATE) == 0);
> 
> 	host_err = vfs_create(&init_user_ns, inode, child, iap->ia_mode, true);
> 	if (host_err < 0) {
> @@ -332,12 +330,9 @@ nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 
> set_attr:
> 	status = nfsd_create_setattr(rqstp, fhp, resfhp, iap);
> -
> +	fh_fill_post_attrs(fhp);
> out:
> -	fh_unlock(fhp);
> -	if (child && !IS_ERR(child))
> -		dput(child);
> -	fh_drop_write(fhp);
> +	done_path_update(&path, child, &wq);
> 	return status;
> }
> 
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 3895eb52d2b1..71a4b8ef77f0 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -285,12 +285,13 @@ static __be32
> nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 		  struct svc_fh *resfhp, struct nfsd4_open *open)
> {
> +	struct path path;
> 	struct iattr *iap = &open->op_iattr;
> -	struct dentry *parent, *child;
> +	struct dentry *child;
> 	__u32 v_mtime, v_atime;
> 	struct inode *inode;
> 	__be32 status;
> -	int host_err;
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	if (isdotent(open->op_fname, open->op_fnamelen))
> 		return nfserr_exist;
> @@ -300,20 +301,17 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 	status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
> 	if (status != nfs_ok)
> 		return status;
> -	parent = fhp->fh_dentry;
> -	inode = d_inode(parent);
> 
> -	host_err = fh_want_write(fhp);
> -	if (host_err)
> -		return nfserrno(host_err);
> +	path.dentry = fhp->fh_dentry;
> +	path.mnt = fhp->fh_export->ex_path.mnt;
> +	inode = d_inode(path.dentry);
> 
> -	fh_lock_nested(fhp, I_MUTEX_PARENT);
> +	child = filename_create_one_len(open->op_fname,
> +					open->op_fnamelen,
> +					&path, 0, &wq);
> 
> -	child = lookup_one_len(open->op_fname, parent, open->op_fnamelen);
> -	if (IS_ERR(child)) {
> -		status = nfserrno(PTR_ERR(child));
> -		goto out;
> -	}
> +	if (IS_ERR(child))
> +		return nfserrno(PTR_ERR(child));
> 
> 	if (d_really_is_negative(child)) {
> 		status = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
> @@ -386,6 +384,7 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 	if (!IS_POSIXACL(inode))
> 		iap->ia_mode &= ~current_umask();
> 
> +	fh_fill_pre_attrs(fhp, (child->d_flags & DCACHE_PAR_UPDATE) == 0);
> 	status = nfsd4_vfs_create(fhp, child, open);
> 	if (status != nfs_ok)
> 		goto out;
> @@ -405,12 +404,9 @@ nfsd4_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 
> set_attr:
> 	status = nfsd_create_setattr(rqstp, fhp, resfhp, iap);
> -
> +	fh_fill_post_attrs(fhp);
> out:
> -	fh_unlock(fhp);
> -	if (child && !IS_ERR(child))
> -		dput(child);
> -	fh_drop_write(fhp);
> +	done_path_update(&path, child, &wq);
> 	return status;
> }
> 
> diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
> index c29baa03dfaf..a50db688c60d 100644
> --- a/fs/nfsd/nfsfh.c
> +++ b/fs/nfsd/nfsfh.c
> @@ -616,7 +616,7 @@ fh_update(struct svc_fh *fhp)
>  * @fhp: file handle to be updated
>  *
>  */
> -void fh_fill_pre_attrs(struct svc_fh *fhp)
> +void fh_fill_pre_attrs(struct svc_fh *fhp, bool atomic)

Hi Neil, just noticed this:

  CC [M]  fs/nfsd/nfsfh.o
  CHECK   /home/cel/src/linux/linux/fs/nfsd/nfsfh.c
/home/cel/src/linux/linux/fs/nfsd/nfsfh.c:621: warning: Function parameter or member 'atomic' not described in 'fh_fill_pre_attrs'

And... do you intend to repost this series with the supplemental
fixes applied?

Should we come up with a plan to merge these during the next
window, or do you feel more work is needed?


> {
> 	bool v4 = (fhp->fh_maxsize == NFS4_FHSIZE);
> 	struct inode *inode;
> @@ -626,6 +626,11 @@ void fh_fill_pre_attrs(struct svc_fh *fhp)
> 	if (fhp->fh_no_wcc || fhp->fh_pre_saved)
> 		return;
> 
> +	if (!atomic) {
> +		fhp->fh_no_atomic_attr = true;
> +		fhp->fh_no_wcc = true;
> +	}
> +
> 	inode = d_inode(fhp->fh_dentry);
> 	err = fh_getattr(fhp, &stat);
> 	if (err) {
> diff --git a/fs/nfsd/nfsfh.h b/fs/nfsd/nfsfh.h
> index fb9d358a267e..ecc57fd3fd67 100644
> --- a/fs/nfsd/nfsfh.h
> +++ b/fs/nfsd/nfsfh.h
> @@ -320,7 +320,7 @@ static inline u64 nfsd4_change_attribute(struct kstat *stat,
> 		return time_to_chattr(&stat->ctime);
> }
> 
> -extern void fh_fill_pre_attrs(struct svc_fh *fhp);
> +extern void fh_fill_pre_attrs(struct svc_fh *fhp, bool atomic);
> extern void fh_fill_post_attrs(struct svc_fh *fhp);
> 
> 
> @@ -347,7 +347,7 @@ fh_lock_nested(struct svc_fh *fhp, unsigned int subclass)
> 
> 	inode = d_inode(dentry);
> 	inode_lock_nested(inode, subclass);
> -	fh_fill_pre_attrs(fhp);
> +	fh_fill_pre_attrs(fhp, true);
> 	fhp->fh_locked = true;
> }
> 
> diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
> index fcdab8a8a41f..2dccf77634e8 100644
> --- a/fs/nfsd/nfsproc.c
> +++ b/fs/nfsd/nfsproc.c
> @@ -255,6 +255,7 @@ nfsd_proc_write(struct svc_rqst *rqstp)
> static __be32
> nfsd_proc_create(struct svc_rqst *rqstp)
> {
> +	struct path path;
> 	struct nfsd_createargs *argp = rqstp->rq_argp;
> 	struct nfsd_diropres *resp = rqstp->rq_resp;
> 	svc_fh		*dirfhp = &argp->fh;
> @@ -263,8 +264,8 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 	struct inode	*inode;
> 	struct dentry	*dchild;
> 	int		type, mode;
> -	int		hosterr;
> 	dev_t		rdev = 0, wanted = new_decode_dev(attr->ia_size);
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	dprintk("nfsd: CREATE   %s %.*s\n",
> 		SVCFH_fmt(dirfhp), argp->len, argp->name);
> @@ -279,17 +280,13 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 	resp->status = nfserr_exist;
> 	if (isdotent(argp->name, argp->len))
> 		goto done;
> -	hosterr = fh_want_write(dirfhp);
> -	if (hosterr) {
> -		resp->status = nfserrno(hosterr);
> -		goto done;
> -	}
> 
> -	fh_lock_nested(dirfhp, I_MUTEX_PARENT);
> -	dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len);
> +	path.dentry = dirfhp->fh_dentry;
> +	path.mnt = dirfhp->fh_export->ex_path.mnt;
> +	dchild = filename_create_one_len(argp->name, argp->len, &path, 0, &wq);
> 	if (IS_ERR(dchild)) {
> 		resp->status = nfserrno(PTR_ERR(dchild));
> -		goto out_unlock;
> +		goto out_done;
> 	}
> 	fh_init(newfhp, NFS_FHSIZE);
> 	resp->status = fh_compose(newfhp, dirfhp->fh_export, dchild, dirfhp);
> @@ -298,7 +295,7 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 	dput(dchild);
> 	if (resp->status) {
> 		if (resp->status != nfserr_noent)
> -			goto out_unlock;
> +			goto out_done;
> 		/*
> 		 * If the new file handle wasn't verified, we can't tell
> 		 * whether the file exists or not. Time to bail ...
> @@ -307,7 +304,7 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 		if (!newfhp->fh_dentry) {
> 			printk(KERN_WARNING 
> 				"nfsd_proc_create: file handle not verified\n");
> -			goto out_unlock;
> +			goto out_done;
> 		}
> 	}
> 
> @@ -341,7 +338,7 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 								 newfhp->fh_dentry,
> 								 NFSD_MAY_WRITE|NFSD_MAY_LOCAL_ACCESS);
> 					if (resp->status && resp->status != nfserr_rofs)
> -						goto out_unlock;
> +						goto out_done;
> 				}
> 			} else
> 				type = S_IFREG;
> @@ -378,7 +375,7 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 		/* Make sure the type and device matches */
> 		resp->status = nfserr_exist;
> 		if (inode && inode_wrong_type(inode, type))
> -			goto out_unlock;
> +			goto out_done;
> 	}
> 
> 	resp->status = nfs_ok;
> @@ -400,10 +397,8 @@ nfsd_proc_create(struct svc_rqst *rqstp)
> 						    (time64_t)0);
> 	}
> 
> -out_unlock:
> -	/* We don't really need to unlock, as fh_put does it. */
> -	fh_unlock(dirfhp);
> -	fh_drop_write(dirfhp);
> +out_done:
> +	done_path_update(&path, dchild, &wq);
> done:
> 	fh_put(dirfhp);
> 	if (resp->status != nfs_ok)
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index 840e3af63a6f..6cdd5e407600 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1274,12 +1274,6 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 	dirp = d_inode(dentry);
> 
> 	dchild = dget(resfhp->fh_dentry);
> -	if (!fhp->fh_locked) {
> -		WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n",
> -				dentry);
> -		err = nfserr_io;
> -		goto out;
> -	}
> 
> 	err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE);
> 	if (err)
> @@ -1362,9 +1356,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 		char *fname, int flen, struct iattr *iap,
> 		int type, dev_t rdev, struct svc_fh *resfhp)
> {
> -	struct dentry	*dentry, *dchild = NULL;
> +	struct path	path;
> +	struct dentry	*dchild = NULL;
> 	__be32		err;
> 	int		host_err;
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	if (isdotent(fname, flen))
> 		return nfserr_exist;
> @@ -1373,27 +1369,22 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 	if (err)
> 		return err;
> 
> -	dentry = fhp->fh_dentry;
> -
> -	host_err = fh_want_write(fhp);
> -	if (host_err)
> -		return nfserrno(host_err);
> +	path.dentry = fhp->fh_dentry;
> +	path.mnt = fhp->fh_export->ex_path.mnt;
> 
> -	fh_lock_nested(fhp, I_MUTEX_PARENT);
> -	dchild = lookup_one_len(fname, dentry, flen);
> +	dchild = filename_create_one_len(fname, flen, &path, 0, &wq);
> 	host_err = PTR_ERR(dchild);
> 	if (IS_ERR(dchild))
> 		return nfserrno(host_err);
> 	err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
> -	/*
> -	 * We unconditionally drop our ref to dchild as fh_compose will have
> -	 * already grabbed its own ref for it.
> -	 */
> -	dput(dchild);
> -	if (err)
> -		return err;
> -	return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
> -					rdev, resfhp);
> +	if (!err) {
> +		fh_fill_pre_attrs(fhp, (dchild->d_flags & DCACHE_PAR_UPDATE) == 0);
> +		err = nfsd_create_locked(rqstp, fhp, fname, flen, iap, type,
> +					 rdev, resfhp);
> +		fh_fill_post_attrs(fhp);
> +	}
> +	done_path_update(&path, dchild, &wq);
> +	return err;
> }
> 
> /*
> @@ -1441,15 +1432,17 @@ nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp)
> __be32
> nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 				char *fname, int flen,
> -				char *path,
> +				char *lpath,
> 				struct svc_fh *resfhp)
> {
> -	struct dentry	*dentry, *dnew;
> +	struct path	path;
> +	struct dentry	*dnew;
> 	__be32		err, cerr;
> 	int		host_err;
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	err = nfserr_noent;
> -	if (!flen || path[0] == '\0')
> +	if (!flen || lpath[0] == '\0')
> 		goto out;
> 	err = nfserr_exist;
> 	if (isdotent(fname, flen))
> @@ -1459,28 +1452,28 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp,
> 	if (err)
> 		goto out;
> 
> -	host_err = fh_want_write(fhp);
> -	if (host_err)
> -		goto out_nfserr;
> +	path.dentry = fhp->fh_dentry;
> +	path.mnt = fhp->fh_export->ex_path.mnt;
> 
> -	fh_lock(fhp);
> -	dentry = fhp->fh_dentry;
> -	dnew = lookup_one_len(fname, dentry, flen);
> +	dnew = filename_create_one_len(fname, flen, &path, 0, &wq);
> 	host_err = PTR_ERR(dnew);
> 	if (IS_ERR(dnew))
> 		goto out_nfserr;
> 
> -	host_err = vfs_symlink(&init_user_ns, d_inode(dentry), dnew, path);
> +	fh_fill_pre_attrs(fhp, (dnew->d_flags & DCACHE_PAR_UPDATE) == 0);
> +	host_err = vfs_symlink(mnt_user_ns(path.mnt), d_inode(path.dentry),
> +			       dnew, lpath);
> 	err = nfserrno(host_err);
> -	fh_unlock(fhp);
> 	if (!err)
> 		err = nfserrno(commit_metadata(fhp));
> 
> -	fh_drop_write(fhp);
> +	fh_fill_post_attrs(fhp);
> 
> 	cerr = fh_compose(resfhp, fhp->fh_export, dnew, fhp);
> -	dput(dnew);
> -	if (err==0) err = cerr;
> +	if (err==0)
> +		err = cerr;
> +
> +	done_path_update(&path, dnew, &wq);
> out:
> 	return err;
> 
> @@ -1497,10 +1490,12 @@ __be32
> nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
> 				char *name, int len, struct svc_fh *tfhp)
> {
> -	struct dentry	*ddir, *dnew, *dold;
> +	struct path	path;
> +	struct dentry	*dold, *dnew;
> 	struct inode	*dirp;
> 	__be32		err;
> 	int		host_err;
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	err = fh_verify(rqstp, ffhp, S_IFDIR, NFSD_MAY_CREATE);
> 	if (err)
> @@ -1518,17 +1513,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
> 	if (isdotent(name, len))
> 		goto out;
> 
> -	host_err = fh_want_write(tfhp);
> -	if (host_err) {
> -		err = nfserrno(host_err);
> -		goto out;
> -	}
> -
> -	fh_lock_nested(ffhp, I_MUTEX_PARENT);
> -	ddir = ffhp->fh_dentry;
> -	dirp = d_inode(ddir);
> +	path.dentry = ffhp->fh_dentry;
> +	path.mnt = ffhp->fh_export->ex_path.mnt;
> +	dirp = d_inode(path.dentry);
> 
> -	dnew = lookup_one_len(name, ddir, len);
> +	dnew = filename_create_one_len(name, len, &path, 0, &wq);
> 	host_err = PTR_ERR(dnew);
> 	if (IS_ERR(dnew))
> 		goto out_nfserr;
> @@ -1537,9 +1526,10 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
> 
> 	err = nfserr_noent;
> 	if (d_really_is_negative(dold))
> -		goto out_dput;
> +		goto out_done;
> +	fh_fill_pre_attrs(ffhp, (dnew->d_flags & DCACHE_PAR_UPDATE) == 0);
> 	host_err = vfs_link(dold, &init_user_ns, dirp, dnew, NULL);
> -	fh_unlock(ffhp);
> +
> 	if (!host_err) {
> 		err = nfserrno(commit_metadata(ffhp));
> 		if (!err)
> @@ -1550,17 +1540,15 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
> 		else
> 			err = nfserrno(host_err);
> 	}
> -out_dput:
> -	dput(dnew);
> -out_unlock:
> -	fh_unlock(ffhp);
> -	fh_drop_write(tfhp);
> +out_done:
> +	fh_fill_post_attrs(ffhp);
> +	done_path_update(&path, dnew, &wq);
> out:
> 	return err;
> 
> out_nfserr:
> 	err = nfserrno(host_err);
> -	goto out_unlock;
> +	goto out;
> }
> 
> static void
> @@ -1625,8 +1613,8 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
> 	 * so do it by hand */
> 	trap = lock_rename(tdentry, fdentry);
> 	ffhp->fh_locked = tfhp->fh_locked = true;
> -	fh_fill_pre_attrs(ffhp);
> -	fh_fill_pre_attrs(tfhp);
> +	fh_fill_pre_attrs(ffhp, true);
> +	fh_fill_pre_attrs(tfhp, true);
> 
> 	odentry = lookup_one_len(fname, fdentry, flen);
> 	host_err = PTR_ERR(odentry);
> @@ -1717,11 +1705,13 @@ __be32
> nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
> 				char *fname, int flen)
> {
> -	struct dentry	*dentry, *rdentry;
> +	struct dentry	*rdentry;
> 	struct inode	*dirp;
> 	struct inode	*rinode;
> 	__be32		err;
> 	int		host_err;
> +	struct path	path;
> +	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
> 
> 	err = nfserr_acces;
> 	if (!flen || isdotent(fname, flen))
> @@ -1730,24 +1720,18 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
> 	if (err)
> 		goto out;
> 
> -	host_err = fh_want_write(fhp);
> -	if (host_err)
> -		goto out_nfserr;
> +	path.mnt = fhp->fh_export->ex_path.mnt;
> +	path.dentry = fhp->fh_dentry;
> 
> -	fh_lock_nested(fhp, I_MUTEX_PARENT);
> -	dentry = fhp->fh_dentry;
> -	dirp = d_inode(dentry);
> +	rdentry = lookup_hash_update_len(fname, flen, &path, 0, &wq);
> +	dirp = d_inode(path.dentry);
> 
> -	rdentry = lookup_one_len(fname, dentry, flen);
> 	host_err = PTR_ERR(rdentry);
> 	if (IS_ERR(rdentry))
> -		goto out_drop_write;
> +		goto out_nfserr;
> +
> +	fh_fill_pre_attrs(fhp, (rdentry->d_flags & DCACHE_PAR_UPDATE) == 0);
> 
> -	if (d_really_is_negative(rdentry)) {
> -		dput(rdentry);
> -		host_err = -ENOENT;
> -		goto out_drop_write;
> -	}
> 	rinode = d_inode(rdentry);
> 	ihold(rinode);
> 
> @@ -1761,15 +1745,13 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
> 	} else {
> 		host_err = vfs_rmdir(&init_user_ns, dirp, rdentry);
> 	}
> +	fh_fill_post_attrs(fhp);
> 
> -	fh_unlock(fhp);
> +	done_path_update(&path, rdentry, &wq);
> 	if (!host_err)
> 		host_err = commit_metadata(fhp);
> -	dput(rdentry);
> 	iput(rinode);    /* truncate the inode here */
> 
> -out_drop_write:
> -	fh_drop_write(fhp);
> out_nfserr:
> 	if (host_err == -EBUSY) {
> 		/* name is mounted-on. There is no perfect
> 
> 

--
Chuck Lever

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