kern: vfs: Add 'create' virtual file operation

The create VOP allows the caller to create a node within the parent
directory of a filesystem represented by a vnode.

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 46 insertions, 0 deletions

diff --git a/src/sys/include/os/vnode.h b/src/sys/include/os/vnode.h
index 1bef1e2..628ba68 100644
--- a/src/sys/include/os/vnode.h
+++ b/src/sys/include/os/vnode.h
@@ -32,6 +32,7 @@
 
 #include <sys/types.h>
 #include <sys/atomic.h>
+#include <sys/namei.h>
 
 /* Forward declarations */
 struct vnode;
@@ -83,12 +84,23 @@ struct vop_rw_data {
 };
 
 /*
+ * Arguments to create an entry within a
+ * filesystem
+ *
+ * @ndp: Path component to create
+ */
+struct vop_create_args {
+    struct nameidata *ndp;
+};
+
+/*
  * Represents operations that can be performed on
  * a specific vnode. These are implemented as callbacks
  */
 struct vop {
     int(*lookup)(struct vop_lookup_args *args);
     int(*reclaim)(struct vnode *vp, int flags);
+    int(*create)(struct vop_create_args *args);
     ssize_t(*write)(struct vop_rw_data *data);
     ssize_t(*read)(struct vop_rw_data *data);
 };
@@ -176,4 +188,16 @@ ssize_t vop_read(struct vnode *vp, char *data, off_t off, size_t len);
  */
 int vop_reclaim(struct vnode *vp, int flags);
 
+/*
+ * Create a node within a specific filesystem or
+ * directory
+ *
+ * @vp: Vnode of parent directory
+ * @ndp: Namei descriptor of path component
+ *
+ * Returns zero on success, otherwise a less than zero
+ * value on failure.
+ */
+int vop_create(struct vnode *vp, struct nameidata *ndp);
+
 #endif  /* !_OS_VNODE_H_ */
diff --git a/src/sys/os/vfs_subr.c b/src/sys/os/vfs_subr.c
index 6cb7767..adfcffb 100644
--- a/src/sys/os/vfs_subr.c
+++ b/src/sys/os/vfs_subr.c
@@ -224,3 +224,25 @@ vop_reclaim(struct vnode *vp, int flags)
 
     return vops->reclaim(vp, flags);
 }
+
+int
+vop_create(struct vnode *vp, struct nameidata *ndp)
+{
+    struct vop *vops;
+    struct vop_create_args args;
+
+    if (vp == NULL || ndp == NULL) {
+        return -EINVAL;
+    }
+
+    if ((vops = vp->vops) == NULL) {
+        return -EIO;
+    }
+
+    if (vops->create == NULL) {
+        return -EIO;
+    }
+
+    args.ndp = ndp;
+    return vops->create(&args);
+}