[PATCH v6 10/17] vfs: make vfs_create break delegations on parent directory

Jeff Layton
2025-11-11T14:13:38Z

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.

Add a delegated_inode parameter to vfs_create. Most callers are
converted to pass in NULL, but do_mknodat() is changed to wait for a
delegation break if there is one.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
fs/ecryptfs/inode.c | 2 +-
fs/namei.c | 15 +++++++++++++--
fs/nfsd/nfs3proc.c | 2 +-
fs/nfsd/vfs.c | 2 +-
fs/open.c | 2 +-
fs/overlayfs/overlayfs.h | 2 +-
fs/smb/server/vfs.c | 2 +-
include/linux/fs.h | 3 ++-
8 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index d109e3763a88150bfe64cd2d5564dc9802ef3386..3341f00dd08753c8feab184dd82b8bfa63d3724a 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -188,7 +188,7 @@ ecryptfs_do_create(struct inode *directory_inode,

rc = lock_parent(ecryptfs_dentry, &lower_dentry, &lower_dir);
if (!rc)
- rc = vfs_create(&nop_mnt_idmap, lower_dentry, mode);
+ rc = vfs_create(&nop_mnt_idmap, lower_dentry, mode, NULL);
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 9586c6aba6eae05a9fc3c103b8501d98767bef53..b20f053374a578d36fb764e0df80fb7db9230dbe 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3463,6 +3463,7 @@ static inline umode_t vfs_prepare_mode(struct mnt_idmap *idmap,
* @idmap: idmap of the mount the inode was found from
* @dentry: dentry of the child file
* @mode: mode of the child file
+ * @di: returns parent inode, if the inode is delegated.
*
* Create a new file.
*
@@ -3472,7 +3473,8 @@ static inline umode_t vfs_prepare_mode(struct mnt_idmap *idmap,
* 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 dentry *dentry, umode_t mode)
+int vfs_create(struct mnt_idmap *idmap, struct dentry *dentry, umode_t mode,
+ struct delegated_inode *di)
{
struct inode *dir = d_inode(dentry->d_parent);
int error;
@@ -3486,6 +3488,9 @@ int vfs_create(struct mnt_idmap *idmap, struct dentry *dentry, umode_t mode)

mode = vfs_prepare_mode(idmap, dir, mode, S_IALLUGO, S_IFREG);
error = security_inode_create(dir, dentry, mode);
+ if (error)
+ return error;
+ error = try_break_deleg(dir, di);
if (error)
return error;
error = dir->i_op->create(idmap, dir, dentry, mode, true);
@@ -4358,6 +4363,7 @@ static int may_mknod(umode_t mode)
static int do_mknodat(int dfd, struct filename *name, umode_t mode,
unsigned int dev)
{
+ struct delegated_inode di = { };
struct mnt_idmap *idmap;
struct dentry *dentry;
struct path path;
@@ -4381,7 +4387,7 @@ 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, dentry, mode);
+ error = vfs_create(idmap, dentry, mode, &di);
if (!error)
security_path_post_mknod(idmap, dentry);
break;
@@ -4396,6 +4402,11 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
}
out2:
end_creating_path(&path, dentry);
+ if (is_delegated(&di)) {
+ error = break_deleg_wait(&di);
+ if (!error)
+ goto retry;
+ }
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index 30ea7ffa2affdb9a959b0fd15a630de056d6dc3c..2cb972b5ed994d69995146aeeac8651c1c04fa46 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -344,7 +344,7 @@ 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, child, iap->ia_mode);
+ host_err = vfs_create(&nop_mnt_idmap, child, iap->ia_mode, NULL);
if (host_err < 0) {
status = nfserrno(host_err);
goto out;
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 464fd54675f3b16fce9ae5f05ad22e0e6b363eb3..de5f46f8c6d3ab24fabddeed9bd59adbe7a486df 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1552,7 +1552,7 @@ 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, dchild, iap->ia_mode);
+ host_err = vfs_create(&nop_mnt_idmap, dchild, iap->ia_mode, NULL);
if (!host_err)
nfsd_check_ignore_resizing(iap);
break;
diff --git a/fs/open.c b/fs/open.c
index e440f58e3ce81e137aabdf00510d839342a19219..92cf2e11781b0efd16fe0b751286ce943ea6b4e2 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1171,7 +1171,7 @@ 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), path->dentry, mode);
+ error = vfs_create(mnt_idmap(path->mnt), path->dentry, mode, NULL);
if (!error)
error = vfs_open(path, f);

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 2bdc434941ebc70f6d4f57cca4f68125112a7bc4..e30441cc9c63ff8b6c055db80be7974501d0023b 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -235,7 +235,7 @@ 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), dentry, mode);
+ int err = vfs_create(ovl_upper_mnt_idmap(ofs), dentry, mode, NULL);

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 83ece2de4b23bf9209137e7ca414a72439b5cc2e..3747851b61c8bad4c00e49866c380c32e9f53a4b 100644
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -188,7 +188,7 @@ int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode)
}

mode |= S_IFREG;
- err = vfs_create(mnt_idmap(path.mnt), dentry, mode);
+ err = vfs_create(mnt_idmap(path.mnt), dentry, mode, NULL);
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 21876ef1fec90181b9878372c7c7e710773aae9f..83b05aec4e10c846d3168018fb62284e45ceb1a8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2111,7 +2111,8 @@ bool inode_owner_or_capable(struct mnt_idmap *idmap,
/*
* VFS helper functions..
*/
-int vfs_create(struct mnt_idmap *, struct dentry *, umode_t);
+int vfs_create(struct mnt_idmap *, struct dentry *, umode_t,
+ struct delegated_inode *);
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