Re: [PATCH v3 04/38] vfs: allow mkdir to wait for delegation break on parent

On Thu, 2025-09-25 at 17:58 +0200, Jan Kara wrote:
> On Wed 24-09-25 14:05:50, Jeff Layton wrote:
> > In order to add directory delegation support, we need to break
> > delegations on the parent whenever there is going to be a change in the
> > directory.
> > 
> > Rename the existing vfs_mkdir to __vfs_mkdir, make it static and add a
> > new delegated_inode parameter. Add a new exported vfs_mkdir wrapper
> > around it that passes a NULL pointer for delegated_inode.
> > 
> > Signed-off-by: Jeff Layton <[email protected]>
> 
> The changelog looks stale (__vfs_mkdir() doesn't exist anymore) but
> otherwise the patch looks good. Feel free to add:
> 
> Reviewed-by: Jan Kara <[email protected]>
> 

Thanks, I realized that I had forgotten to fix it after I sent it.

> 								Honza
> 
> > ---
> >  drivers/base/devtmpfs.c  |  2 +-
> >  fs/cachefiles/namei.c    |  2 +-
> >  fs/ecryptfs/inode.c      |  2 +-
> >  fs/init.c                |  2 +-
> >  fs/namei.c               | 24 ++++++++++++++++++------
> >  fs/nfsd/nfs4recover.c    |  2 +-
> >  fs/nfsd/vfs.c            |  2 +-
> >  fs/overlayfs/overlayfs.h |  2 +-
> >  fs/smb/server/vfs.c      |  2 +-
> >  fs/xfs/scrub/orphanage.c |  2 +-
> >  include/linux/fs.h       |  2 +-
> >  11 files changed, 28 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
> > index 31bfb3194b4c29a1d6a002449045bf4e4141911d..a57da600ce7523e9e2755b78f75342bf4fa56ef6 100644
> > --- a/drivers/base/devtmpfs.c
> > +++ b/drivers/base/devtmpfs.c
> > @@ -180,7 +180,7 @@ static int dev_mkdir(const char *name, umode_t mode)
> >  	if (IS_ERR(dentry))
> >  		return PTR_ERR(dentry);
> >  
> > -	dentry = vfs_mkdir(&nop_mnt_idmap, d_inode(path.dentry), dentry, mode);
> > +	dentry = vfs_mkdir(&nop_mnt_idmap, d_inode(path.dentry), dentry, mode, NULL);
> >  	if (!IS_ERR(dentry))
> >  		/* mark as kernel-created inode */
> >  		d_inode(dentry)->i_private = &thread;
> > diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
> > index 91dfd02318772fa63050ecf40fa5625ab48ad589..b3dac91efec622261186fbba8e704ae9e782bea0 100644
> > --- a/fs/cachefiles/namei.c
> > +++ b/fs/cachefiles/namei.c
> > @@ -130,7 +130,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
> >  			goto mkdir_error;
> >  		ret = cachefiles_inject_write_error();
> >  		if (ret == 0)
> > -			subdir = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700);
> > +			subdir = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700, NULL);
> >  		else
> >  			subdir = ERR_PTR(ret);
> >  		if (IS_ERR(subdir)) {
> > diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> > index 72fbe1316ab8831bb4228d573278f32fe52b6b25..00f54c125b102856c33ffff24627475f40dcbc7b 100644
> > --- a/fs/ecryptfs/inode.c
> > +++ b/fs/ecryptfs/inode.c
> > @@ -517,7 +517,7 @@ static struct dentry *ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
> >  		goto out;
> >  
> >  	lower_dentry = vfs_mkdir(&nop_mnt_idmap, lower_dir,
> > -				 lower_dentry, mode);
> > +				 lower_dentry, mode, NULL);
> >  	rc = PTR_ERR(lower_dentry);
> >  	if (IS_ERR(lower_dentry))
> >  		goto out;
> > diff --git a/fs/init.c b/fs/init.c
> > index eef5124885e372ac020d2923692116c5e884b3cf..dd5240ce8ad41f02367a54ddf1b6ac0aa28e9721 100644
> > --- a/fs/init.c
> > +++ b/fs/init.c
> > @@ -232,7 +232,7 @@ int __init init_mkdir(const char *pathname, umode_t mode)
> >  	error = security_path_mkdir(&path, dentry, mode);
> >  	if (!error) {
> >  		dentry = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode,
> > -				  dentry, mode);
> > +				  dentry, mode, NULL);
> >  		if (IS_ERR(dentry))
> >  			error = PTR_ERR(dentry);
> >  	}
> > diff --git a/fs/namei.c b/fs/namei.c
> > index cd517eb232317d326e6d2fc5a60cb4c7569a137d..c939a58f16f9c4edded424475aff52f2c423d301 100644
> > --- a/fs/namei.c
> > +++ b/fs/namei.c
> > @@ -4320,10 +4320,11 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
> >  
> >  /**
> >   * vfs_mkdir - create directory returning correct dentry if possible
> > - * @idmap:	idmap of the mount the inode was found from
> > - * @dir:	inode of the parent directory
> > - * @dentry:	dentry of the child directory
> > - * @mode:	mode of the child directory
> > + * @idmap:		idmap of the mount the inode was found from
> > + * @dir:		inode of the parent directory
> > + * @dentry:		dentry of the child directory
> > + * @mode:		mode of the child directory
> > + * @delegated_inode:	returns victim inode, if the inode is delegated.
> >   *
> >   * Create a directory.
> >   *
> > @@ -4340,7 +4341,8 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
> >   * In case of an error the dentry is dput() and an ERR_PTR() is returned.
> >   */
> >  struct dentry *vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
> > -			 struct dentry *dentry, umode_t mode)
> > +			 struct dentry *dentry, umode_t mode,
> > +			 struct inode **delegated_inode)
> >  {
> >  	int error;
> >  	unsigned max_links = dir->i_sb->s_max_links;
> > @@ -4363,6 +4365,10 @@ struct dentry *vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
> >  	if (max_links && dir->i_nlink >= max_links)
> >  		goto err;
> >  
> > +	error = try_break_deleg(dir, delegated_inode);
> > +	if (error)
> > +		goto err;
> > +
> >  	de = dir->i_op->mkdir(idmap, dir, dentry, mode);
> >  	error = PTR_ERR(de);
> >  	if (IS_ERR(de))
> > @@ -4386,6 +4392,7 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode)
> >  	struct path path;
> >  	int error;
> >  	unsigned int lookup_flags = LOOKUP_DIRECTORY;
> > +	struct inode *delegated_inode = NULL;
> >  
> >  retry:
> >  	dentry = filename_create(dfd, name, &path, lookup_flags);
> > @@ -4397,11 +4404,16 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode)
> >  			mode_strip_umask(path.dentry->d_inode, mode));
> >  	if (!error) {
> >  		dentry = vfs_mkdir(mnt_idmap(path.mnt), path.dentry->d_inode,
> > -				  dentry, mode);
> > +				   dentry, mode, &delegated_inode);
> >  		if (IS_ERR(dentry))
> >  			error = PTR_ERR(dentry);
> >  	}
> >  	done_path_create(&path, dentry);
> > +	if (delegated_inode) {
> > +		error = break_deleg_wait(&delegated_inode);
> > +		if (!error)
> > +			goto retry;
> > +	}
> >  	if (retry_estale(error, lookup_flags)) {
> >  		lookup_flags |= LOOKUP_REVAL;
> >  		goto retry;
> > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> > index b1005abcb9035b2cf743200808a251b00af7e3f4..423dd102b51198ea7c447be2b9a0a5020c950dba 100644
> > --- a/fs/nfsd/nfs4recover.c
> > +++ b/fs/nfsd/nfs4recover.c
> > @@ -202,7 +202,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp)
> >  		 * as well be forgiving and just succeed silently.
> >  		 */
> >  		goto out_put;
> > -	dentry = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), dentry, S_IRWXU);
> > +	dentry = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), dentry, 0700, NULL);
> >  	if (IS_ERR(dentry))
> >  		status = PTR_ERR(dentry);
> >  out_put:
> > diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> > index 2026431500ecbc0cf5fb5d4af1a7632c611ce4f4..6f1275fdc8ac831aa0ea8da588f751eddff88df1 100644
> > --- a/fs/nfsd/vfs.c
> > +++ b/fs/nfsd/vfs.c
> > @@ -1560,7 +1560,7 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
> >  			nfsd_check_ignore_resizing(iap);
> >  		break;
> >  	case S_IFDIR:
> > -		dchild = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode);
> > +		dchild = vfs_mkdir(&nop_mnt_idmap, dirp, dchild, iap->ia_mode, NULL);
> >  		if (IS_ERR(dchild)) {
> >  			host_err = PTR_ERR(dchild);
> >  		} else if (d_is_negative(dchild)) {
> > diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> > index bb0d7ded8e763a4a7a6fc506d966ed2f3bdb4f06..4a3a22f422c37d45e49a762cd3c9957aa2c6a485 100644
> > --- a/fs/overlayfs/overlayfs.h
> > +++ b/fs/overlayfs/overlayfs.h
> > @@ -248,7 +248,7 @@ static inline struct dentry *ovl_do_mkdir(struct ovl_fs *ofs,
> >  {
> >  	struct dentry *ret;
> >  
> > -	ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
> > +	ret = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, NULL);
> >  	pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, PTR_ERR_OR_ZERO(ret));
> >  	return ret;
> >  }
> > diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
> > index 04539037108c93e285f4e9d6aa61f93a507ae5da..b0fb73b277876a56797f5cc8a5aa53f156bb7a26 100644
> > --- a/fs/smb/server/vfs.c
> > +++ b/fs/smb/server/vfs.c
> > @@ -229,7 +229,7 @@ int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode)
> >  	idmap = mnt_idmap(path.mnt);
> >  	mode |= S_IFDIR;
> >  	d = dentry;
> > -	dentry = vfs_mkdir(idmap, d_inode(path.dentry), dentry, mode);
> > +	dentry = vfs_mkdir(idmap, d_inode(path.dentry), dentry, mode, NULL);
> >  	if (IS_ERR(dentry))
> >  		err = PTR_ERR(dentry);
> >  	else if (d_is_negative(dentry))
> > diff --git a/fs/xfs/scrub/orphanage.c b/fs/xfs/scrub/orphanage.c
> > index 9c12cb8442311ca26b169e4d1567939ae44a5be0..91c9d07b97f306f57aebb9b69ba564b0c2cb8c17 100644
> > --- a/fs/xfs/scrub/orphanage.c
> > +++ b/fs/xfs/scrub/orphanage.c
> > @@ -167,7 +167,7 @@ xrep_orphanage_create(
> >  	 */
> >  	if (d_really_is_negative(orphanage_dentry)) {
> >  		orphanage_dentry = vfs_mkdir(&nop_mnt_idmap, root_inode,
> > -					     orphanage_dentry, 0750);
> > +					     orphanage_dentry, 0750, NULL);
> >  		error = PTR_ERR(orphanage_dentry);
> >  		if (IS_ERR(orphanage_dentry))
> >  			goto out_unlock_root;
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index 74f2bfc519263c6411a8e3427e1bd6680a1121db..24a091509f12ce65a2c8343d438fccf423d3062b 100644
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -1997,7 +1997,7 @@ bool inode_owner_or_capable(struct mnt_idmap *idmap,
> >  int vfs_create(struct mnt_idmap *, struct inode *,
> >  	       struct dentry *, umode_t, bool);
> >  struct dentry *vfs_mkdir(struct mnt_idmap *, struct inode *,
> > -			 struct dentry *, umode_t);
> > +			 struct dentry *, umode_t, struct inode **);
> >  int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
> >                umode_t, dev_t);
> >  int vfs_symlink(struct mnt_idmap *, struct inode *,
> > 
> > -- 
> > 2.51.0
> > 

-- 
Jeff Layton <[email protected]>