From patchwork Mon Apr 18 21:37:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 12817130 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9A5AEC433F5 for ; Mon, 18 Apr 2022 21:37:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2B14F8D0023; Mon, 18 Apr 2022 17:37:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 264A08D001A; Mon, 18 Apr 2022 17:37:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0DBEB8D0023; Mon, 18 Apr 2022 17:37:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id EC32F8D001A for ; Mon, 18 Apr 2022 17:37:27 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id B4407606BC for ; Mon, 18 Apr 2022 21:37:27 +0000 (UTC) X-FDA: 79371311334.18.A1D3158 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by imf23.hostedemail.com (Postfix) with ESMTP id 44DD3140008 for ; Mon, 18 Apr 2022 21:37:27 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: krisman) with ESMTPSA id 2117C1F419FC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1650317846; bh=Y+ucbxeR+Qi5rPHrBhvrhU/yGHcw5E2wDEXDS0A6lTA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L9CgekMQMobPNA/RLWz4ovzCY0yGOFDl8V/g4lc9S1gl6ccLy58WhtNDUHuyHD+G8 radeF2PEzd4xCBi5HHl1lCBjoeedo8GWRvo51FZNxcn5zc+K0BmiRgTS2IeCzoVuvl mDRyqXT/ncSV7XbRUyDfvlFQnZ72jx0MswnjYCYm9xzktnAn2D1xFYBnL64E0qP1RK 3CkGxjPCu1ATn8HNruvg5o3QWnuHdaX/4kTh3aNhh80iqog4DljGeSoOlGLV6ON94i 4qeLSFi0N7r6iqPOm1rmU395Ck9GR7XAe+rZo8wHjUZjhfHhlPTja3Ww3Ohzf4gIg1 5wk4el4Dr96Qw== From: Gabriel Krisman Bertazi To: hughd@google.com, akpm@linux-foundation.org, amir73il@gmail.com Cc: viro@zeniv.linux.org.uk, Gabriel Krisman Bertazi , kernel@collabora.com, Khazhismel Kumykov , Linux MM , linux-fsdevel Subject: [PATCH v3 2/3] shmem: Introduce /sys/fs/tmpfs support Date: Mon, 18 Apr 2022 17:37:12 -0400 Message-Id: <20220418213713.273050-3-krisman@collabora.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220418213713.273050-1-krisman@collabora.com> References: <20220418213713.273050-1-krisman@collabora.com> MIME-Version: 1.0 Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=collabora.com header.s=mail header.b=L9CgekMQ; spf=pass (imf23.hostedemail.com: domain of krisman@collabora.com designates 46.235.227.227 as permitted sender) smtp.mailfrom=krisman@collabora.com; dmarc=pass (policy=none) header.from=collabora.com X-Stat-Signature: 4bp1fh4nryn4ijw6yc3eeg1wu5zpsycd X-Rspamd-Queue-Id: 44DD3140008 X-Rspamd-Server: rspam04 X-Rspam-User: X-HE-Tag: 1650317847-978014 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: In order to expose tmpfs statistics on sysfs, add the boilerplate code to create the /sys/fs/tmpfs structure. As suggested on a previous review, this uses the minor as the volume directory in /sys/fs/. This takes care of not exposing SB_NOUSER mounts. I don't think we have a usecase for showing them and, since they don't appear elsewhere, they might be confusing to users. Signed-off-by: Gabriel Krisman Bertazi Reported-by: kernel test robot Reported-by: Dan Carpenter --- Changes since v2: - Use kobject to release sbinfo (Viro) Changes since v1: - Use minor instead of fsid for directory in sysfs. (Amir) --- include/linux/shmem_fs.h | 2 ++ mm/shmem.c | 46 +++++++++++++++++++++++++++++++++++++--- 2 files changed, 45 insertions(+), 3 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 1a7cd9ea9107..6c1f3a4b8c46 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -47,6 +47,8 @@ struct shmem_sb_info { unsigned long acct_errors; unsigned long space_errors; + + struct kobject kobj; }; static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) diff --git a/mm/shmem.c b/mm/shmem.c index c350fa0a0fff..8fe4a22e83a6 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -250,6 +250,7 @@ static const struct inode_operations shmem_dir_inode_operations; static const struct inode_operations shmem_special_inode_operations; static const struct vm_operations_struct shmem_vm_ops; static struct file_system_type shmem_fs_type; +static struct kobject *shmem_root; bool vma_is_shmem(struct vm_area_struct *vma) { @@ -3582,17 +3583,44 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root) return 0; } +#if defined(CONFIG_SYSFS) +#define TMPFS_SB_ATTR_RO(name) \ + static struct kobj_attribute tmpfs_sb_attr_##name = __ATTR_RO(name) + +static struct attribute *tmpfs_attrs[] = { + NULL +}; +ATTRIBUTE_GROUPS(tmpfs); +#endif /* CONFIG_SYSFS */ + #endif /* CONFIG_TMPFS */ -static void shmem_put_super(struct super_block *sb) +static void tmpfs_sb_release(struct kobject *kobj) { - struct shmem_sb_info *sbinfo = SHMEM_SB(sb); + struct shmem_sb_info *sbinfo = + container_of(kobj, struct shmem_sb_info, kobj); free_percpu(sbinfo->ino_batch); percpu_counter_destroy(&sbinfo->used_blocks); mpol_put(sbinfo->mpol); kfree(sbinfo); +} + +static struct kobj_type tmpfs_sb_ktype = { +#if defined(CONFIG_TMPFS) && defined(CONFIG_SYSFS) + .default_groups = tmpfs_groups, +#endif + .sysfs_ops = &kobj_sysfs_ops, + .release = tmpfs_sb_release, +}; + +static void shmem_put_super(struct super_block *sb) +{ + struct shmem_sb_info *sbinfo = SHMEM_SB(sb); + sb->s_fs_info = NULL; + + kobject_put(&sbinfo->kobj); } static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) @@ -3608,6 +3636,7 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) return -ENOMEM; sb->s_fs_info = sbinfo; + kobject_init(&sbinfo->kobj, &tmpfs_sb_ktype); #ifdef CONFIG_TMPFS /* @@ -3673,6 +3702,11 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_root = d_make_root(inode); if (!sb->s_root) goto failed; + + if (!(sb->s_flags & SB_NOUSER) && + kobject_add(&sbinfo->kobj, shmem_root, "%d", MINOR(sb->s_dev))) + goto failed; + return 0; failed: @@ -3889,11 +3923,15 @@ int __init shmem_init(void) goto out2; } + shmem_root = kobject_create_and_add("tmpfs", fs_kobj); + if (!shmem_root) + goto out1; + shm_mnt = kern_mount(&shmem_fs_type); if (IS_ERR(shm_mnt)) { error = PTR_ERR(shm_mnt); pr_err("Could not kern_mount tmpfs\n"); - goto out1; + goto put_kobj; } #ifdef CONFIG_TRANSPARENT_HUGEPAGE @@ -3904,6 +3942,8 @@ int __init shmem_init(void) #endif return 0; +put_kobj: + kobject_put(shmem_root); out1: unregister_filesystem(&shmem_fs_type); out2: