From patchwork Tue Oct 31 22:33:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 160370 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:abcd:0:b0:403:3b70:6f57 with SMTP id f13csp61623vqx; Tue, 31 Oct 2023 15:34:43 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEa7/9w5qZU1Y6TFcjN/az3zplWh4/R7PWq2Y89B21ZpoedSOelnJvIf2QJEv0M4CIkNd7z X-Received: by 2002:a05:6e02:338f:b0:359:3150:c69d with SMTP id bn15-20020a056e02338f00b003593150c69dmr4656014ilb.9.1698791683276; Tue, 31 Oct 2023 15:34:43 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1698791683; cv=none; d=google.com; s=arc-20160816; b=RdXWR7cre6YZg/OQu97wuSy3H0RqdjpRy/w+EIyyrmV61uhKFY0cKDK39jWM2kWiR8 uTsY1anYPmZfazk9WUzr/UUNTatwCvQZaSD8ajM3yaI4yKE0jWzhrxD7weHGnJMQTRv9 crNg2p0GaGhujHR5uKFSBNYH7tyojHZhxs5ryooqVnHtJR6mHKHuktl5jCMt/+3VVQ0Y x5Wqjp42ldQGFEcqRNQo5y8UIeRSyUHMork3jUW+E52az7h2BcYmt2B1f607IHtscEaV gMDjfFuVjAM6KynArM5kuN63U0xxAecycnBCgA/JyMGqReFUxvYv31SeCxPuNypPje+w mdUQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:references:subject:cc:to:from:date :user-agent:message-id; bh=tEP9YlhEGAsgRxzTWzG05ul4f/GQapgygI1SNm+MVmg=; fh=p9qaSGjxjg7fXhZ2SPcVaCB443dWE9yY5/nXWowH5kM=; b=jJkcgVKxSp5lB/ejFgC9ka9Kkc8poKPUAO2nI1L1T+QG9Q029OBXFvBhQzY7LoTLFY 4sFqoMDeEBIdG/H4Cm+ze2S8h4jtlykRdbFrxWvdmUGGOK7BF+SD3biw1hOeU1nx2uu6 IFj2H0IY1X3Oqm8Gk2J8oSn0jiJygHnD3Yh5gfBq2Za0kTCp63ZrxbqejgdrHrNDRuh1 HMKqkC836NVBa015OhBfLtVtuQUiFy+zc7gHIxHFrIc81e7L96WPW67bPGhKPK8btsby 0mY3MNxJxU86flb+8AH1vJ509v9PYR7omVGCoZhdvsNTtsRJnO5wV1/AFojOiHfmSJNI aVfQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from snail.vger.email (snail.vger.email. [23.128.96.37]) by mx.google.com with ESMTPS id a22-20020a056a000c9600b006b9aef36fe8si294409pfv.292.2023.10.31.15.34.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 Oct 2023 15:34:43 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) client-ip=23.128.96.37; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id 4435881121DB; Tue, 31 Oct 2023 15:34:42 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376334AbjJaWej (ORCPT + 33 others); Tue, 31 Oct 2023 18:34:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346797AbjJaWe0 (ORCPT ); Tue, 31 Oct 2023 18:34:26 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 30C69FE for ; Tue, 31 Oct 2023 15:34:23 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C57EDC433C8; Tue, 31 Oct 2023 22:34:22 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.96) (envelope-from ) id 1qxxJU-00EPiX-2R; Tue, 31 Oct 2023 18:34:20 -0400 Message-ID: <20231031223420.568912586@goodmis.org> User-Agent: quilt/0.66 Date: Tue, 31 Oct 2023 18:33:30 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Ajay Kaher , Andrew Morton Subject: [PATCH v5 4/7] eventfs: Save ownership and mode References: <20231031223326.794680978@goodmis.org> MIME-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Tue, 31 Oct 2023 15:34:42 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1781312188391563416 X-GMAIL-MSGID: 1781312188391563416 From: "Steven Rostedt (Google)" Now that inodes and dentries are created on the fly, they are also reclaimed on memory pressure. Since the ownership and file mode are saved in the inode, if they are freed, any changes to the ownership and mode will be lost. To counter this, if the user changes the permissions or ownership, save them, and when creating the inodes again, restore those changes. Signed-off-by: Steven Rostedt (Google) Reviewed-by: Masami Hiramatsu (Google) --- Changes since v4: https://lkml.kernel.org/r/20231031193428.558586557@goodmis.org - Rebased to this series fs/tracefs/event_inode.c | 148 +++++++++++++++++++++++++++++++++++---- fs/tracefs/internal.h | 16 +++++ 2 files changed, 151 insertions(+), 13 deletions(-) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index b28f240bbb6d..d1683bf6d316 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -40,6 +40,15 @@ static DEFINE_MUTEX(eventfs_mutex); */ DEFINE_STATIC_SRCU(eventfs_srcu); +/* Mode is unsigned short, use the upper bits for flags */ +enum { + EVENTFS_SAVE_MODE = BIT(16), + EVENTFS_SAVE_UID = BIT(17), + EVENTFS_SAVE_GID = BIT(18), +}; + +#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1) + static struct dentry *eventfs_root_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); @@ -47,8 +56,89 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file); static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx); static int eventfs_release(struct inode *inode, struct file *file); +static void update_attr(struct eventfs_attr *attr, struct iattr *iattr) +{ + unsigned int ia_valid = iattr->ia_valid; + + if (ia_valid & ATTR_MODE) { + attr->mode = (attr->mode & ~EVENTFS_MODE_MASK) | + (iattr->ia_mode & EVENTFS_MODE_MASK) | + EVENTFS_SAVE_MODE; + } + if (ia_valid & ATTR_UID) { + attr->mode |= EVENTFS_SAVE_UID; + attr->uid = iattr->ia_uid; + } + if (ia_valid & ATTR_GID) { + attr->mode |= EVENTFS_SAVE_GID; + attr->gid = iattr->ia_gid; + } +} + +static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry, + struct iattr *iattr) +{ + const struct eventfs_entry *entry; + struct eventfs_inode *ei; + const char *name; + int ret; + + mutex_lock(&eventfs_mutex); + ei = dentry->d_fsdata; + /* The LSB is set when the eventfs_inode is being freed */ + if (((unsigned long)ei & 1UL) || ei->is_freed) { + /* Do not allow changes if the event is about to be removed. */ + mutex_unlock(&eventfs_mutex); + return -ENODEV; + } + + /* Preallocate the children mode array if necessary */ + if (!(dentry->d_inode->i_mode & S_IFDIR)) { + if (!ei->entry_attrs) { + ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, + GFP_KERNEL); + if (!ei->entry_attrs) { + ret = -ENOMEM; + goto out; + } + } + } + + ret = simple_setattr(idmap, dentry, iattr); + if (ret < 0) + goto out; + + /* + * If this is a dir, then update the ei cache, only the file + * mode is saved in the ei->m_children, and the ownership is + * determined by the parent directory. + */ + if (dentry->d_inode->i_mode & S_IFDIR) { + update_attr(&ei->attr, iattr); + + } else { + name = dentry->d_name.name; + + for (int i = 0; i < ei->nr_entries; i++) { + entry = &ei->entries[i]; + if (strcmp(name, entry->name) == 0) { + update_attr(&ei->entry_attrs[i], iattr); + break; + } + } + } + out: + mutex_unlock(&eventfs_mutex); + return ret; +} + static const struct inode_operations eventfs_root_dir_inode_operations = { .lookup = eventfs_root_lookup, + .setattr = eventfs_set_attr, +}; + +static const struct inode_operations eventfs_file_inode_operations = { + .setattr = eventfs_set_attr, }; static const struct file_operations eventfs_file_operations = { @@ -59,10 +149,30 @@ static const struct file_operations eventfs_file_operations = { .release = eventfs_release, }; +static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode) +{ + if (!attr) { + inode->i_mode = mode; + return; + } + + if (attr->mode & EVENTFS_SAVE_MODE) + inode->i_mode = attr->mode & EVENTFS_MODE_MASK; + else + inode->i_mode = mode; + + if (attr->mode & EVENTFS_SAVE_UID) + inode->i_uid = attr->uid; + + if (attr->mode & EVENTFS_SAVE_GID) + inode->i_gid = attr->gid; +} + /** * create_file - create a file in the tracefs filesystem * @name: the name of the file to create. * @mode: the permission that the file should have. + * @attr: saved attributes changed by user * @parent: parent dentry for this file. * @data: something that the caller will want to get to later on. * @fop: struct file_operations that should be used for this file. @@ -72,6 +182,7 @@ static const struct file_operations eventfs_file_operations = { * call. */ static struct dentry *create_file(const char *name, umode_t mode, + struct eventfs_attr *attr, struct dentry *parent, void *data, const struct file_operations *fop) { @@ -95,7 +206,10 @@ static struct dentry *create_file(const char *name, umode_t mode, if (unlikely(!inode)) return eventfs_failed_creating(dentry); - inode->i_mode = mode; + /* If the user updated the directory's attributes, use them */ + update_inode_attr(inode, attr, mode); + + inode->i_op = &eventfs_file_inode_operations; inode->i_fop = fop; inode->i_private = data; @@ -108,19 +222,19 @@ static struct dentry *create_file(const char *name, umode_t mode, /** * create_dir - create a dir in the tracefs filesystem - * @name: the name of the file to create. + * @ei: the eventfs_inode that represents the directory to create * @parent: parent dentry for this file. * * This function will create a dentry for a directory represented by * a eventfs_inode. */ -static struct dentry *create_dir(const char *name, struct dentry *parent) +static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent) { struct tracefs_inode *ti; struct dentry *dentry; struct inode *inode; - dentry = eventfs_start_creating(name, parent); + dentry = eventfs_start_creating(ei->name, parent); if (IS_ERR(dentry)) return dentry; @@ -128,7 +242,9 @@ static struct dentry *create_dir(const char *name, struct dentry *parent) if (unlikely(!inode)) return eventfs_failed_creating(dentry); - inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; + /* If the user updated the directory's attributes, use them */ + update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO); + inode->i_op = &eventfs_root_dir_inode_operations; inode->i_fop = &eventfs_file_operations; @@ -146,6 +262,7 @@ static void free_ei(struct eventfs_inode *ei) { kfree_const(ei->name); kfree(ei->d_children); + kfree(ei->entry_attrs); kfree(ei); } @@ -231,7 +348,7 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry) /** * create_file_dentry - create a dentry for a file of an eventfs_inode * @ei: the eventfs_inode that the file will be created under - * @e_dentry: a pointer to the d_children[] of the @ei + * @idx: the index into the d_children[] of the @ei * @parent: The parent dentry of the created file. * @name: The name of the file to create * @mode: The mode of the file. @@ -244,10 +361,12 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry) * just do a dget() on it and return. Otherwise create the dentry and attach it. */ static struct dentry * -create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry, +create_file_dentry(struct eventfs_inode *ei, int idx, struct dentry *parent, const char *name, umode_t mode, void *data, const struct file_operations *fops, bool lookup) { + struct eventfs_attr *attr = NULL; + struct dentry **e_dentry = &ei->d_children[idx]; struct dentry *dentry; bool invalidate = false; @@ -264,13 +383,18 @@ create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry, mutex_unlock(&eventfs_mutex); return *e_dentry; } + + /* ei->entry_attrs are protected by SRCU */ + if (ei->entry_attrs) + attr = &ei->entry_attrs[idx]; + mutex_unlock(&eventfs_mutex); /* The lookup already has the parent->d_inode locked */ if (!lookup) inode_lock(parent->d_inode); - dentry = create_file(name, mode, parent, data, fops); + dentry = create_file(name, mode, attr, parent, data, fops); if (!lookup) inode_unlock(parent->d_inode); @@ -378,7 +502,7 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei, if (!lookup) inode_lock(parent->d_inode); - dentry = create_dir(ei->name, parent); + dentry = create_dir(ei, parent); if (!lookup) inode_unlock(parent->d_inode); @@ -495,8 +619,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, if (r <= 0) continue; ret = simple_lookup(dir, dentry, flags); - create_file_dentry(ei, &ei->d_children[i], - ei_dentry, name, mode, cdata, + create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops, true); break; } @@ -629,8 +752,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file) r = entry->callback(name, &mode, &cdata, &fops); if (r <= 0) continue; - d = create_file_dentry(ei, &ei->d_children[i], - parent, name, mode, cdata, fops, false); + d = create_file_dentry(ei, i, parent, name, mode, cdata, fops, false); if (d) { ret = add_dentries(&dentries, d, cnt); if (ret < 0) diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h index 5a98e87dd3d1..5f60bcd69289 100644 --- a/fs/tracefs/internal.h +++ b/fs/tracefs/internal.h @@ -13,6 +13,18 @@ struct tracefs_inode { struct inode vfs_inode; }; +/* + * struct eventfs_attr - cache the mode and ownership of a eventfs entry + * @mode: saved mode plus flags of what is saved + * @uid: saved uid if changed + * @gid: saved gid if changed + */ +struct eventfs_attr { + int mode; + kuid_t uid; + kgid_t gid; +}; + /* * struct eventfs_inode - hold the properties of the eventfs directories. * @list: link list into the parent directory @@ -22,6 +34,8 @@ struct tracefs_inode { * @dentry: the dentry of the directory * @d_parent: pointer to the parent's dentry * @d_children: The array of dentries to represent the files when created + * @entry_attrs: Saved mode and ownership of the @d_children + * @attr: Saved mode and ownership of eventfs_inode itself * @data: The private data to pass to the callbacks * @is_freed: Flag set if the eventfs is on its way to be freed * Note if is_freed is set, then dentry is corrupted. @@ -35,6 +49,8 @@ struct eventfs_inode { struct dentry *dentry; /* Check is_freed to access */ struct dentry *d_parent; struct dentry **d_children; + struct eventfs_attr *entry_attrs; + struct eventfs_attr attr; void *data; /* * Union - used for deletion