From nobody Sun Feb 8 11:45:09 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A5EEC001DF for ; Mon, 31 Jul 2023 23:17:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232012AbjGaXRu (ORCPT ); Mon, 31 Jul 2023 19:17:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231926AbjGaXRe (ORCPT ); Mon, 31 Jul 2023 19:17:34 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05E12E46 for ; Mon, 31 Jul 2023 16:17:16 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 28D9F61366 for ; Mon, 31 Jul 2023 23:17:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5874C433C9; Mon, 31 Jul 2023 23:17:07 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1qQc8Q-003fOk-2r; Mon, 31 Jul 2023 19:17:06 -0400 Message-ID: <20230731231706.704342866@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 31 Jul 2023 19:16:43 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton , Ajay Kaher , Ching-lin Yu , kernel test robot Subject: [for-next][PATCH 09/15] eventfs: Implement eventfs dir creation functions References: <20230731231634.031452225@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ajay Kaher Add eventfs_file structure which will hold the properties of the eventfs files and directories. Add following functions to create the directories in eventfs: eventfs_create_events_dir() will create the top level "events" directory within the tracefs file system. eventfs_add_subsystem_dir() creates an eventfs_file descriptor with the given name of the subsystem. eventfs_add_dir() creates an eventfs_file descriptor with the given name of the directory and attached to a eventfs_file of a subsystem. Add tracefs_inode structure to hold the inodes, flags and pointers to private data used by eventfs. Link: https://lkml.kernel.org/r/1690568452-46553-5-git-send-email-akaher@vm= ware.com Signed-off-by: Ajay Kaher Co-developed-by: Steven Rostedt (VMware) Signed-off-by: Steven Rostedt (VMware) Tested-by: Ching-lin Yu Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202305051619.9a469a9a-yujie.liu@inte= l.com Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/Makefile | 1 + fs/tracefs/event_inode.c | 211 +++++++++++++++++++++++++++++++++++++++ fs/tracefs/internal.h | 4 + include/linux/tracefs.h | 11 ++ 4 files changed, 227 insertions(+) create mode 100644 fs/tracefs/event_inode.c diff --git a/fs/tracefs/Makefile b/fs/tracefs/Makefile index 7c35a282b484..73c56da8e284 100644 --- a/fs/tracefs/Makefile +++ b/fs/tracefs/Makefile @@ -1,5 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only tracefs-objs :=3D inode.o +tracefs-objs +=3D event_inode.o =20 obj-$(CONFIG_TRACING) +=3D tracefs.o =20 diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c new file mode 100644 index 000000000000..8f334b122e46 --- /dev/null +++ b/fs/tracefs/event_inode.c @@ -0,0 +1,211 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * event_inode.c - part of tracefs, a pseudo file system for activating t= racing + * + * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt (VMware) + * Copyright (C) 2020-23 VMware Inc, author: Ajay Kaher + * + * eventfs is used to dynamically create inodes and dentries based on the + * meta data provided by the tracing system. + * + * eventfs stores the meta-data of files/dirs and holds off on creating + * inodes/dentries of the files. When accessed, the eventfs will create t= he + * inodes/dentries in a just-in-time (JIT) manner. The eventfs will clean= up + * and delete the inodes/dentries when they are no longer referenced. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +struct eventfs_inode { + struct list_head e_top_files; +}; + +/** + * struct eventfs_file - hold the properties of the eventfs files and + * directories. + * @name: the name of the file or directory to create + * @list: file or directory to be added to parent directory + * @ei: list of files and directories within directory + * @fop: file_operations for file or directory + * @iop: inode_operations for file or directory + * @data: something that the caller will want to get to later on + * @mode: the permission that the file or directory should have + */ +struct eventfs_file { + const char *name; + struct list_head list; + struct eventfs_inode *ei; + const struct file_operations *fop; + const struct inode_operations *iop; + void *data; + umode_t mode; +}; + +static DEFINE_MUTEX(eventfs_mutex); + +static const struct inode_operations eventfs_root_dir_inode_operations =3D= { +}; + +static const struct file_operations eventfs_file_operations =3D { +}; + +/** + * eventfs_prepare_ef - helper function to prepare eventfs_file + * @name: the name of the file/directory to create. + * @mode: the permission that the file should have. + * @fop: struct file_operations that should be used for this file/director= y. + * @iop: struct inode_operations that should be used for this file/directo= ry. + * @data: something that the caller will want to get to later on. The + * inode.i_private pointer will point to this value on the open() c= all. + * + * This function allocates and fills the eventfs_file structure. + */ +static struct eventfs_file *eventfs_prepare_ef(const char *name, umode_t m= ode, + const struct file_operations *fop, + const struct inode_operations *iop, + void *data) +{ + struct eventfs_file *ef; + + ef =3D kzalloc(sizeof(*ef), GFP_KERNEL); + if (!ef) + return ERR_PTR(-ENOMEM); + + ef->name =3D kstrdup(name, GFP_KERNEL); + if (!ef->name) { + kfree(ef); + return ERR_PTR(-ENOMEM); + } + + if (S_ISDIR(mode)) { + ef->ei =3D kzalloc(sizeof(*ef->ei), GFP_KERNEL); + if (!ef->ei) { + kfree(ef->name); + kfree(ef); + return ERR_PTR(-ENOMEM); + } + INIT_LIST_HEAD(&ef->ei->e_top_files); + } else { + ef->ei =3D NULL; + } + + ef->iop =3D iop; + ef->fop =3D fop; + ef->mode =3D mode; + ef->data =3D data; + return ef; +} + +/** + * eventfs_create_events_dir - create the trace event structure + * @name: the name of the directory to create. + * @parent: parent dentry for this file. This should be a directory dentry + * if set. If this parameter is NULL, then the directory will be + * created in the root of the tracefs filesystem. + * + * This function creates the top of the trace event directory. + */ +struct dentry *eventfs_create_events_dir(const char *name, + struct dentry *parent) +{ + struct dentry *dentry =3D tracefs_start_creating(name, parent); + struct eventfs_inode *ei; + struct tracefs_inode *ti; + struct inode *inode; + + if (IS_ERR(dentry)) + return dentry; + + ei =3D kzalloc(sizeof(*ei), GFP_KERNEL); + if (!ei) + return ERR_PTR(-ENOMEM); + inode =3D tracefs_get_inode(dentry->d_sb); + if (unlikely(!inode)) { + kfree(ei); + tracefs_failed_creating(dentry); + return ERR_PTR(-ENOMEM); + } + + INIT_LIST_HEAD(&ei->e_top_files); + + ti =3D get_tracefs(inode); + ti->flags |=3D TRACEFS_EVENT_INODE; + ti->private =3D ei; + + inode->i_mode =3D S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + inode->i_op =3D &eventfs_root_dir_inode_operations; + inode->i_fop =3D &eventfs_file_operations; + + /* directory inodes start off with i_nlink =3D=3D 2 (for "." entry) */ + inc_nlink(inode); + d_instantiate(dentry, inode); + inc_nlink(dentry->d_parent->d_inode); + fsnotify_mkdir(dentry->d_parent->d_inode, dentry); + return tracefs_end_creating(dentry); +} + +/** + * eventfs_add_subsystem_dir - add eventfs subsystem_dir to list to create= later + * @name: the name of the file to create. + * @parent: parent dentry for this dir. + * + * This function adds eventfs subsystem dir to list. + * And all these dirs are created on the fly when they are looked up, + * and the dentry and inodes will be removed when they are done. + */ +struct eventfs_file *eventfs_add_subsystem_dir(const char *name, + struct dentry *parent) +{ + struct tracefs_inode *ti_parent; + struct eventfs_inode *ei_parent; + struct eventfs_file *ef; + + if (!parent) + return ERR_PTR(-EINVAL); + + ti_parent =3D get_tracefs(parent->d_inode); + ei_parent =3D ti_parent->private; + + ef =3D eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL); + if (IS_ERR(ef)) + return ef; + + mutex_lock(&eventfs_mutex); + list_add_tail(&ef->list, &ei_parent->e_top_files); + mutex_unlock(&eventfs_mutex); + return ef; +} + +/** + * eventfs_add_dir - add eventfs dir to list to create later + * @name: the name of the file to create. + * @ef_parent: parent eventfs_file for this dir. + * + * This function adds eventfs dir to list. + * And all these dirs are created on the fly when they are looked up, + * and the dentry and inodes will be removed when they are done. + */ +struct eventfs_file *eventfs_add_dir(const char *name, + struct eventfs_file *ef_parent) +{ + struct eventfs_file *ef; + + if (!ef_parent) + return ERR_PTR(-EINVAL); + + ef =3D eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL); + if (IS_ERR(ef)) + return ef; + + mutex_lock(&eventfs_mutex); + list_add_tail(&ef->list, &ef_parent->ei->e_top_files); + mutex_unlock(&eventfs_mutex); + return ef; +} diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h index 7dfb7ebc1c3f..f0fd565d59ec 100644 --- a/fs/tracefs/internal.h +++ b/fs/tracefs/internal.h @@ -2,6 +2,10 @@ #ifndef _TRACEFS_INTERNAL_H #define _TRACEFS_INTERNAL_H =20 +enum { + TRACEFS_EVENT_INODE =3D BIT(1), +}; + struct tracefs_inode { unsigned long flags; void *private; diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h index 99912445974c..432e5e6f7901 100644 --- a/include/linux/tracefs.h +++ b/include/linux/tracefs.h @@ -21,6 +21,17 @@ struct file_operations; =20 #ifdef CONFIG_TRACING =20 +struct eventfs_file; + +struct dentry *eventfs_create_events_dir(const char *name, + struct dentry *parent); + +struct eventfs_file *eventfs_add_subsystem_dir(const char *name, + struct dentry *parent); + +struct eventfs_file *eventfs_add_dir(const char *name, + struct eventfs_file *ef_parent); + struct dentry *tracefs_create_file(const char *name, umode_t mode, struct dentry *parent, void *data, const struct file_operations *fops); --=20 2.40.1