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Message-id: <176221480589.1793333.7801494824880510264@noble.neil.brown.name>
Date: Tue, 04 Nov 2025 11:06:45 +1100
From: NeilBrown <neilb@...mail.net>
To: "Jeff Layton" <jlayton@...nel.org>
Cc: "Miklos Szeredi" <miklos@...redi.hu>,
"Alexander Viro" <viro@...iv.linux.org.uk>,
"Christian Brauner" <brauner@...nel.org>, "Jan Kara" <jack@...e.cz>,
"Chuck Lever" <chuck.lever@...cle.com>,
"Alexander Aring" <alex.aring@...il.com>,
"Trond Myklebust" <trondmy@...nel.org>,
"Anna Schumaker" <anna@...nel.org>, "Steve French" <sfrench@...ba.org>,
"Paulo Alcantara" <pc@...guebit.org>,
"Ronnie Sahlberg" <ronniesahlberg@...il.com>,
"Shyam Prasad N" <sprasad@...rosoft.com>, "Tom Talpey" <tom@...pey.com>,
"Bharath SM" <bharathsm@...rosoft.com>,
"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
"Danilo Krummrich" <dakr@...nel.org>,
"David Howells" <dhowells@...hat.com>, "Tyler Hicks" <code@...icks.com>,
"Olga Kornievskaia" <okorniev@...hat.com>,
"Dai Ngo" <Dai.Ngo@...cle.com>, "Amir Goldstein" <amir73il@...il.com>,
"Namjae Jeon" <linkinjeon@...nel.org>,
"Steve French" <smfrench@...il.com>,
"Sergey Senozhatsky" <senozhatsky@...omium.org>,
"Carlos Maiolino" <cem@...nel.org>,
"Kuniyuki Iwashima" <kuniyu@...gle.com>,
"David S. Miller" <davem@...emloft.net>,
"Eric Dumazet" <edumazet@...gle.com>, "Jakub Kicinski" <kuba@...nel.org>,
"Paolo Abeni" <pabeni@...hat.com>, "Simon Horman" <horms@...nel.org>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-nfs@...r.kernel.org, linux-cifs@...r.kernel.org,
samba-technical@...ts.samba.org, netfs@...ts.linux.dev,
ecryptfs@...r.kernel.org, linux-unionfs@...r.kernel.org,
linux-xfs@...r.kernel.org, netdev@...r.kernel.org,
"Jeff Layton" <jlayton@...nel.org>
Subject: Re: [PATCH v4 09/17] vfs: add struct createdata for passing arguments
to vfs_create()
On Mon, 03 Nov 2025, Jeff Layton wrote:
> vfs_create() has grown an uncomfortably long argument list, and a
> following patch will add another. Convert it to take a new struct
> createdata pointer and fix up the callers to pass one in.
>
I know Christian asked for this and he is a Maintainer so.....
but I would like say that I don't think this is a win. The argument
list isn't *that* long, and all the args are quite different so there is
little room for confusion.
I would be in favour of dropping the "dir" arg because it is always
d_inode(dentry->d_parent)
which is stable.
I would rather pass the vfsmnt rather than the idmap, then we could pass
"struct path", for both that and dentry, but I know Christian disagrees.
So if anyone really thinks the arg list is too long, I think there are
better solutions. But I don't even think the length is a problem.
NeilBrown
> Signed-off-by: Jeff Layton <jlayton@...nel.org>
> ---
> fs/ecryptfs/inode.c | 11 ++++++++---
> fs/namei.c | 33 ++++++++++++++++++++-------------
> fs/nfsd/nfs3proc.c | 9 ++++++++-
> fs/nfsd/vfs.c | 19 ++++++++++++-------
> fs/open.c | 9 ++++++---
> fs/overlayfs/overlayfs.h | 7 ++++++-
> fs/smb/server/vfs.c | 9 +++++++--
> include/linux/fs.h | 13 +++++++++++--
> 8 files changed, 78 insertions(+), 32 deletions(-)
>
> diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> index 88631291b32535f623a3fbe4ea9b6ed48a306ca0..51accd166dbf515eb5221b6a39b204622a6b0f7c 100644
> --- a/fs/ecryptfs/inode.c
> +++ b/fs/ecryptfs/inode.c
> @@ -187,9 +187,14 @@ ecryptfs_do_create(struct inode *directory_inode,
> struct inode *inode;
>
> rc = lock_parent(ecryptfs_dentry, &lower_dentry, &lower_dir);
> - if (!rc)
> - rc = vfs_create(&nop_mnt_idmap, lower_dir,
> - lower_dentry, mode, true);
> + if (!rc) {
> + struct createdata args = { .idmap = &nop_mnt_idmap,
> + .dir = lower_dir,
> + .dentry = lower_dentry,
> + .mode = mode,
> + .excl = true };
> + rc = vfs_create(&args);
> + }
> if (rc) {
> printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
> "rc = [%d]\n", __func__, rc);
> diff --git a/fs/namei.c b/fs/namei.c
> index f439429bdfa271ccc64c937771ef4175597feb53..fdf4e78cd041de8c564b7d1d89a46ba2aaf79d53 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -3460,23 +3460,22 @@ static inline umode_t vfs_prepare_mode(struct mnt_idmap *idmap,
>
> /**
> * vfs_create - create new file
> - * @idmap: idmap of the mount the inode was found from
> - * @dir: inode of the parent directory
> - * @dentry: dentry of the child file
> - * @mode: mode of the child file
> - * @want_excl: whether the file must not yet exist
> + * @args: struct createdata describing create to be done
> *
> * Create a new file.
> *
> * If the inode has been found through an idmapped mount the idmap of
> - * the vfsmount must be passed through @idmap. This function will then take
> - * care to map the inode according to @idmap before checking permissions.
> + * the vfsmount must be passed through @args->idmap. This function will then take
> + * care to map the inode according to @args->idmap before checking permissions.
> * On non-idmapped mounts or if permission checking is to be performed on the
> * raw inode simply pass @nop_mnt_idmap.
> */
> -int vfs_create(struct mnt_idmap *idmap, struct inode *dir,
> - struct dentry *dentry, umode_t mode, bool want_excl)
> +int vfs_create(struct createdata *args)
> {
> + struct mnt_idmap *idmap = args->idmap;
> + struct inode *dir = args->dir;
> + struct dentry *dentry = args->dentry;
> + umode_t mode = args->mode;
> int error;
>
> error = may_create(idmap, dir, dentry);
> @@ -3490,7 +3489,7 @@ int vfs_create(struct mnt_idmap *idmap, struct inode *dir,
> error = security_inode_create(dir, dentry, mode);
> if (error)
> return error;
> - error = dir->i_op->create(idmap, dir, dentry, mode, want_excl);
> + error = dir->i_op->create(idmap, dir, dentry, mode, args->excl);
> if (!error)
> fsnotify_create(dir, dentry);
> return error;
> @@ -4382,12 +4381,20 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
>
> idmap = mnt_idmap(path.mnt);
> switch (mode & S_IFMT) {
> - case 0: case S_IFREG:
> - error = vfs_create(idmap, path.dentry->d_inode,
> - dentry, mode, true);
> + case 0:
> + case S_IFREG:
> + {
> + struct createdata args = { .idmap = idmap,
> + .dir = path.dentry->d_inode,
> + .dentry = dentry,
> + .mode = mode,
> + .excl = true };
> +
> + error = vfs_create(&args);
> if (!error)
> security_path_post_mknod(idmap, dentry);
> break;
> + }
> case S_IFCHR: case S_IFBLK:
> error = vfs_mknod(idmap, path.dentry->d_inode,
> dentry, mode, new_decode_dev(dev));
> diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
> index b6d03e1ef5f7a5e8dd111b0d56c061f1e91abff7..dcd7de465e7e33d1c66ee0272c4f220d55e85928 100644
> --- a/fs/nfsd/nfs3proc.c
> +++ b/fs/nfsd/nfs3proc.c
> @@ -258,6 +258,7 @@ nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> struct nfsd_attrs attrs = {
> .na_iattr = iap,
> };
> + struct createdata cargs = { };
> __u32 v_mtime, v_atime;
> struct inode *inode;
> __be32 status;
> @@ -344,7 +345,13 @@ nfsd3_create_file(struct svc_rqst *rqstp, struct svc_fh *fhp,
> status = fh_fill_pre_attrs(fhp);
> if (status != nfs_ok)
> goto out;
> - host_err = vfs_create(&nop_mnt_idmap, inode, child, iap->ia_mode, true);
> +
> + cargs.idmap = &nop_mnt_idmap;
> + cargs.dir = inode;
> + cargs.dentry = child;
> + cargs.mode = iap->ia_mode;
> + cargs.excl = true;
> + host_err = vfs_create(&cargs);
> if (host_err < 0) {
> status = nfserrno(host_err);
> goto out;
> diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
> index c400ea94ff2e837fd59719bf2c4b79ef1d064743..e4ed1952f02c0a66c64528e59453cc9b2352c18f 100644
> --- a/fs/nfsd/vfs.c
> +++ b/fs/nfsd/vfs.c
> @@ -1527,11 +1527,12 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
> struct nfsd_attrs *attrs,
> int type, dev_t rdev, struct svc_fh *resfhp)
> {
> - struct dentry *dentry, *dchild;
> - struct inode *dirp;
> - struct iattr *iap = attrs->na_iattr;
> - __be32 err;
> - int host_err = 0;
> + struct dentry *dentry, *dchild;
> + struct inode *dirp;
> + struct iattr *iap = attrs->na_iattr;
> + __be32 err;
> + int host_err = 0;
> + struct createdata cargs = { };
>
> dentry = fhp->fh_dentry;
> dirp = d_inode(dentry);
> @@ -1552,8 +1553,12 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
> err = 0;
> switch (type) {
> case S_IFREG:
> - host_err = vfs_create(&nop_mnt_idmap, dirp, dchild,
> - iap->ia_mode, true);
> + cargs.idmap = &nop_mnt_idmap;
> + cargs.dir = dirp;
> + cargs.dentry = dchild;
> + cargs.mode = iap->ia_mode;
> + cargs.excl = true;
> + host_err = vfs_create(&cargs);
> if (!host_err)
> nfsd_check_ignore_resizing(iap);
> break;
> diff --git a/fs/open.c b/fs/open.c
> index fdaa6f08f6f4cac5c2fefd3eafa5e430e51f3979..006cc2aeb1fbbb3db48b32db798108da120f75c2 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -1164,6 +1164,11 @@ struct file *dentry_open_nonotify(const struct path *path, int flags,
> struct file *dentry_create(const struct path *path, int flags, umode_t mode,
> const struct cred *cred)
> {
> + struct createdata cargs = { .idmap = mnt_idmap(path->mnt),
> + .dir = d_inode(path->dentry->d_parent),
> + .dentry = path->dentry,
> + .mode = mode,
> + .excl = true };
> struct file *f;
> int error;
>
> @@ -1171,9 +1176,7 @@ struct file *dentry_create(const struct path *path, int flags, umode_t mode,
> if (IS_ERR(f))
> return f;
>
> - error = vfs_create(mnt_idmap(path->mnt),
> - d_inode(path->dentry->d_parent),
> - path->dentry, mode, true);
> + error = vfs_create(&cargs);
> if (!error)
> error = vfs_open(path, f);
>
> diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> index d215d7349489686b66bb66e939b27046f7d836f6..5fa939ac842ed04df8f0088233f4cba4ac703c05 100644
> --- a/fs/overlayfs/overlayfs.h
> +++ b/fs/overlayfs/overlayfs.h
> @@ -235,7 +235,12 @@ static inline int ovl_do_create(struct ovl_fs *ofs,
> struct inode *dir, struct dentry *dentry,
> umode_t mode)
> {
> - int err = vfs_create(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, true);
> + struct createdata cargs = { .idmap = ovl_upper_mnt_idmap(ofs),
> + .dir = dir,
> + .dentry = dentry,
> + .mode = mode,
> + .excl = true };
> + int err = vfs_create(&cargs);
>
> pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
> return err;
> diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
> index c5f0f3170d586cb2dc4d416b80948c642797fb82..fbc3c34e14b870f1750b945349335afb62d89d0d 100644
> --- a/fs/smb/server/vfs.c
> +++ b/fs/smb/server/vfs.c
> @@ -173,6 +173,7 @@ void ksmbd_vfs_query_maximal_access(struct mnt_idmap *idmap,
> */
> int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode)
> {
> + struct createdata cargs = { };
> struct path path;
> struct dentry *dentry;
> int err;
> @@ -188,8 +189,12 @@ int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode)
> }
>
> mode |= S_IFREG;
> - err = vfs_create(mnt_idmap(path.mnt), d_inode(path.dentry),
> - dentry, mode, true);
> + cargs.idmap = mnt_idmap(path.mnt);
> + cargs.dir = d_inode(path.dentry);
> + cargs.dentry = dentry;
> + cargs.mode = mode;
> + cargs.excl = true;
> + err = vfs_create(&cargs);
> if (!err) {
> ksmbd_vfs_inherit_owner(work, d_inode(path.dentry),
> d_inode(dentry));
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 12873214e1c7811735ea5d2dee3d57e2a5604d8f..b61873767b37591aecadd147623d7dfc866bef82 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2111,8 +2111,17 @@ bool inode_owner_or_capable(struct mnt_idmap *idmap,
> /*
> * VFS helper functions..
> */
> -int vfs_create(struct mnt_idmap *, struct inode *,
> - struct dentry *, umode_t, bool);
> +
> +struct createdata {
> + struct mnt_idmap *idmap; // idmap of the mount the inode was found from
> + struct inode *dir; // inode of parent directory
> + struct dentry *dentry; // dentry of the child file
> + umode_t mode; // mode of the child file
> + bool excl; // whether the file must not yet exist
> +};
> +
> +int vfs_create(struct createdata *);
> +
> struct dentry *vfs_mkdir(struct mnt_idmap *, struct inode *,
> struct dentry *, umode_t, struct delegated_inode *);
> int vfs_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
>
> --
> 2.51.1
>
>
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