From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0DB21509AC; Tue, 20 Feb 2024 21:22:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708464128; cv=none; b=AXpDa2A1/Pdith6+XkF3FC5PM5kySW8pH6rNNe/fSlc+bqhKGiLIG5gYuu/ejbpMutjSRKaxYBQE+YAokHjMd7JYTRlF4qojEkSJZD/FfNHhWP75QMMeT0Wg3uEUZ7Nb5KTPrjsGcfssknYbZj6g7gRAjsO+ILMINaqlQkKJWvc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708464128; c=relaxed/simple; bh=au50i5Ur79yu9XK5ejn66SGD6+wmmm/Dm3TO9xD9QxI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PQqvyDmpiBS4zA1ia0pffTWmu5ZKfxVAddYbGXHRPPgCkJZU3ImnfvAD+42KsBZxHSJa+7WnuQ4MVngDnq0qTSWUgWEe6tfMdj1wPDD2uJarMhKeFlrjhR5aDX4aMay5Ie+KLckjf/5BVF11hzcaI8m4dh6Rvt2FxNSejH+9/3M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fBbWhw/D; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fBbWhw/D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F1D4C433C7; Tue, 20 Feb 2024 21:22:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708464128; bh=au50i5Ur79yu9XK5ejn66SGD6+wmmm/Dm3TO9xD9QxI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fBbWhw/DZxZnsMtV3AJ4FeexO39H47fKW9rZ8XN1W72p3875K48v38F3QhQd0asxF ZIN6wyTeWY+pZS+ugAnotRCoH7Cj8KYpz+dglFmYIrukiWinblU7Ne4GkrwDOxZBpJ VUBKlGjaBODLcU7fMA5lJUt5oL2eBIl9EwfLz1Zc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Steven Rostedt (Google)" Subject: [PATCH 6.6 260/331] Revert "eventfs: Use simple_recursive_removal() to clean up dentries" Date: Tue, 20 Feb 2024 21:56:16 +0100 Message-ID: <20240220205646.038292109@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240220205637.572693592@linuxfoundation.org> References: <20240220205637.572693592@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Steven Rostedt (Google)" This reverts commit 055907ad2c14838c90d63297f7bab8d180a5d844. The eventfs was not designed properly and may have some hidden bugs in it. Linus rewrote it properly and I trust his version more than this one. Revert the backported patches for 6.6 and re-apply all the changes to make it equivalent to Linus's version. Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- fs/tracefs/event_inode.c | 71 +++++++++++++++++++++++++---------------------- 1 file changed, 38 insertions(+), 33 deletions(-) --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -54,10 +54,12 @@ struct eventfs_file { /* * Union - used for deletion * @llist: for calling dput() if needed after RCU + * @del_list: list of eventfs_file to delete * @rcu: eventfs_file to delete in RCU */ union { struct llist_node llist; + struct list_head del_list; struct rcu_head rcu; }; void *data; @@ -274,6 +276,7 @@ static void free_ef(struct eventfs_file */ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry) { + struct tracefs_inode *ti_parent; struct eventfs_inode *ei; struct eventfs_file *ef; @@ -294,6 +297,10 @@ void eventfs_set_ef_status_free(struct t mutex_lock(&eventfs_mutex); + ti_parent = get_tracefs(dentry->d_parent->d_inode); + if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE)) + goto out; + ef = dentry->d_fsdata; if (!ef) goto out; @@ -866,29 +873,30 @@ static void unhook_dentry(struct dentry { if (!dentry) return; - /* - * Need to add a reference to the dentry that is expected by - * simple_recursive_removal(), which will include a dput(). - */ - dget(dentry); - /* - * Also add a reference for the dput() in eventfs_workfn(). - * That is required as that dput() will free the ei after - * the SRCU grace period is over. - */ + /* Keep the dentry from being freed yet (see eventfs_workfn()) */ dget(dentry); + + dentry->d_fsdata = NULL; + d_invalidate(dentry); + mutex_lock(&eventfs_mutex); + /* dentry should now have at least a single reference */ + WARN_ONCE((int)d_count(dentry) < 1, + "dentry %px (%s) less than one reference (%d) after invalidate\n", + dentry, dentry->d_name.name, d_count(dentry)); + mutex_unlock(&eventfs_mutex); } /** * eventfs_remove_rec - remove eventfs dir or file from list * @ef: eventfs_file to be removed. + * @head: to create list of eventfs_file to be deleted * @level: to check recursion depth * * The helper function eventfs_remove_rec() is used to clean up and free the * associated data from eventfs for both of the added functions. */ -static void eventfs_remove_rec(struct eventfs_file *ef, int level) +static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head, int level) { struct eventfs_file *ef_child; @@ -908,16 +916,14 @@ static void eventfs_remove_rec(struct ev /* search for nested folders or files */ list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list, lockdep_is_held(&eventfs_mutex)) { - eventfs_remove_rec(ef_child, level + 1); + eventfs_remove_rec(ef_child, head, level + 1); } } ef->is_freed = 1; - unhook_dentry(ef->dentry); - list_del_rcu(&ef->list); - call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef); + list_add_tail(&ef->del_list, head); } /** @@ -928,22 +934,28 @@ static void eventfs_remove_rec(struct ev */ void eventfs_remove(struct eventfs_file *ef) { - struct dentry *dentry; + struct eventfs_file *tmp; + LIST_HEAD(ef_del_list); if (!ef) return; + /* + * Move the deleted eventfs_inodes onto the ei_del_list + * which will also set the is_freed value. Note, this has to be + * done under the eventfs_mutex, but the deletions of + * the dentries must be done outside the eventfs_mutex. + * Hence moving them to this temporary list. + */ mutex_lock(&eventfs_mutex); - dentry = ef->dentry; - eventfs_remove_rec(ef, 0); + eventfs_remove_rec(ef, &ef_del_list, 0); mutex_unlock(&eventfs_mutex); - /* - * If any of the ei children has a dentry, then the ei itself - * must have a dentry. - */ - if (dentry) - simple_recursive_removal(dentry, NULL); + list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) { + unhook_dentry(ef->dentry); + list_del(&ef->del_list); + call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef); + } } /** @@ -954,8 +966,6 @@ void eventfs_remove(struct eventfs_file */ void eventfs_remove_events_dir(struct dentry *dentry) { - struct eventfs_file *ef_child; - struct eventfs_inode *ei; struct tracefs_inode *ti; if (!dentry || !dentry->d_inode) @@ -965,11 +975,6 @@ void eventfs_remove_events_dir(struct de if (!ti || !(ti->flags & TRACEFS_EVENT_INODE)) return; - mutex_lock(&eventfs_mutex); - ei = ti->private; - list_for_each_entry_srcu(ef_child, &ei->e_top_files, list, - lockdep_is_held(&eventfs_mutex)) { - eventfs_remove_rec(ef_child, 0); - } - mutex_unlock(&eventfs_mutex); + d_invalidate(dentry); + dput(dentry); }