[PATCH v5 14/14] VFS: introduce end_creating_keep()

NeilBrown
2025-11-06T00:57:14Z

From: NeilBrown <neil@brown.name>

Occasionally the caller of end_creating() wants to keep using the dentry.
Rather then requiring them to dget() the dentry (when not an error)
before calling end_creating(), provide end_creating_keep() which does
this.

cachefiles and overlayfs make use of this.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: NeilBrown <neil@brown.name>
---
fs/cachefiles/namei.c | 3 +--
fs/overlayfs/dir.c | 8 ++------
fs/overlayfs/super.c | 11 +++--------
include/linux/namei.h | 22 ++++++++++++++++++++++
4 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 59327618ac42..ef22ac19545b 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -155,8 +155,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,

/* Tell rmdir() it's not allowed to delete the subdir */
inode_lock(d_inode(subdir));
- dget(subdir);
- end_creating(subdir);
+ end_creating_keep(subdir);

if (!__cachefiles_mark_inode_in_use(NULL, d_inode(subdir))) {
pr_notice("cachefiles: Inode already in use: %pd (B=%lx)\n",
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index a4a0dc261310..50717ff8cac7 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -252,10 +252,7 @@ struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
if (IS_ERR(ret))
return ret;
ret = ovl_create_real(ofs, workdir, ret, attr);
- if (!IS_ERR(ret))
- dget(ret);
- end_creating(ret);
- return ret;
+ return end_creating_keep(ret);
}

static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
@@ -365,8 +362,7 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
if (IS_ERR(newdentry))
return PTR_ERR(newdentry);

- dget(newdentry);
- end_creating(newdentry);
+ end_creating_keep(newdentry);

if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
!ovl_allow_offline_changes(ofs)) {
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 3acda985c8a3..7b8fc1cab6eb 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -319,8 +319,7 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
};

if (work->d_inode) {
- dget(work);
- end_creating(work);
+ end_creating_keep(work);
if (persist)
return work;
err = -EEXIST;
@@ -336,9 +335,7 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
}

work = ovl_do_mkdir(ofs, dir, work, attr.ia_mode);
- if (!IS_ERR(work))
- dget(work);
- end_creating(work);
+ end_creating_keep(work);
err = PTR_ERR(work);
if (IS_ERR(work))
goto out_err;
@@ -630,9 +627,7 @@ static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs,
if (!child->d_inode)
child = ovl_create_real(ofs, parent, child,
OVL_CATTR(mode));
- if (!IS_ERR(child))
- dget(child);
- end_creating(child);
+ end_creating_keep(child);
}
dput(parent);

diff --git a/include/linux/namei.h b/include/linux/namei.h
index b4d95b79b5a8..58600cf234bc 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -126,6 +126,28 @@ static inline void end_creating(struct dentry *child)
end_dirop(child);
}

+/* end_creating_keep - finish action started with start_creating() and return result
+ * @child: dentry returned by start_creating() or vfs_mkdir()
+ *
+ * Unlock and return the child. This can be called after
+ * start_creating() whether that function succeeded or not,
+ * but it is not needed on failure.
+ *
+ * If vfs_mkdir() was called then the value returned from that function
+ * should be given for @child rather than the original dentry, as vfs_mkdir()
+ * may have provided a new dentry.
+ *
+ * Returns: @child, which may be a dentry or an error.
+ *
+ */
+static inline struct dentry *end_creating_keep(struct dentry *child)
+{
+ if (!IS_ERR(child))
+ dget(child);
+ end_dirop(child);
+ return child;
+}
+
/**
* end_removing - finish action started with start_removing
* @child: dentry returned by start_removing()
--
2.50.0.107.gf914562f5916.dirty