+static struct file *
+v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
+ struct opendata *od, unsigned flags, umode_t mode,
+ bool *created)
+{
+ int err;
+ u32 perm;
+ struct file *filp;
+ struct v9fs_inode *v9inode;
+ struct v9fs_session_info *v9ses;
+ struct p9_fid *fid, *inode_fid;
+ struct dentry *res = NULL;
+
+ if (d_unhashed(dentry)) {
+ res = v9fs_vfs_lookup(dir, dentry, NULL);
+ if (IS_ERR(res))
+ return ERR_CAST(res);
+
+ if (res)
+ dentry = res;
+ }
+
+ /* Only creates */
+ if (!(flags & O_CREAT) || dentry->d_inode) {
+ finish_no_open(od, res);
+ return NULL;
+ }
+
+ err = 0;
+ fid = NULL;
+ v9ses = v9fs_inode2v9ses(dir);
+ perm = unixmode2p9mode(v9ses, mode);
+ fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
+ v9fs_uflags2omode(flags,
+ v9fs_proto_dotu(v9ses)));
+ if (IS_ERR(fid)) {
+ err = PTR_ERR(fid);
+ fid = NULL;
+ goto error;
+ }
+
+ v9fs_invalidate_inode_attr(dir);
+ v9inode = V9FS_I(dentry->d_inode);
+ mutex_lock(&v9inode->v_mutex);
+ if (v9ses->cache && !v9inode->writeback_fid &&
+ ((flags & O_ACCMODE) != O_RDONLY)) {
+ /*
+ * clone a fid and add it to writeback_fid
+ * we do it during open time instead of
+ * page dirty time via write_begin/page_mkwrite
+ * because we want write after unlink usecase
+ * to work.
+ */
+ inode_fid = v9fs_writeback_fid(dentry);
+ if (IS_ERR(inode_fid)) {
+ err = PTR_ERR(inode_fid);
+ mutex_unlock(&v9inode->v_mutex);
+ goto error;
+ }
+ v9inode->writeback_fid = (void *) inode_fid;
+ }
+ mutex_unlock(&v9inode->v_mutex);
+ filp = finish_open(od, dentry, generic_file_open);
+ if (IS_ERR(filp)) {
+ err = PTR_ERR(filp);
+ goto error;
+ }
+
+ filp->private_data = fid;
+#ifdef CONFIG_9P_FSCACHE
+ if (v9ses->cache)
+ v9fs_cache_inode_set_cookie(dentry->d_inode, filp);
+#endif
+
+ *created = true;
+out:
+ dput(res);
+ return filp;
+
+error:
+ if (fid)
+ p9_client_clunk(fid);
+
+ filp = ERR_PTR(err);
+ goto out;
+}
+