Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753160AbdFNQNc (ORCPT ); Wed, 14 Jun 2017 12:13:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:47538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752956AbdFNQM0 (ORCPT ); Wed, 14 Jun 2017 12:12:26 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5AD5239E2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=shli@fb.com From: Shaohua Li To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Cc: tj@kernel.org, gregkh@linuxfoundation.org, hch@lst.de, axboe@fb.com, rostedt@goodmis.org, lizefan@huawei.com, Kernel-team@fb.com, Shaohua Li Subject: [PATCH V2 01/12] kernfs: implement i_generation Date: Wed, 14 Jun 2017 09:11:59 -0700 Message-Id: <74c46215969a0506d7529e559c1f7f2d3885d1e2.1497455937.git.shli@fb.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2230 Lines: 72 From: Shaohua Li Set i_generation for kernfs inode. This is required to implement exportfs operations. Note, the generation is 32-bit, so it's possible the generation wraps up and we find stale files. The possiblity is low, since fhandle matches both inode number and generation. In most fs, the generation is 32-bit. fhandle only export 32-bit generation for most fs. So unless we have solid reason, we'd live with the possible conflict. Signed-off-by: Shaohua Li --- fs/kernfs/dir.c | 2 ++ fs/kernfs/inode.c | 1 + include/linux/kernfs.h | 2 ++ 3 files changed, 5 insertions(+) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index db5900aaa..09d093e 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -634,6 +634,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root, if (ret < 0) goto err_out2; kn->ino = ret; + kn->generation = atomic_inc_return(&root->next_generation); atomic_set(&kn->count, 1); atomic_set(&kn->active, KN_DEACTIVATED_BIAS); @@ -877,6 +878,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, ida_init(&root->ino_ida); INIT_LIST_HEAD(&root->supers); + atomic_set(&root->next_generation, 0); kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR); diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c index fb4b4a7..79cdae4 100644 --- a/fs/kernfs/inode.c +++ b/fs/kernfs/inode.c @@ -220,6 +220,7 @@ static void kernfs_init_inode(struct kernfs_node *kn, struct inode *inode) inode->i_private = kn; inode->i_mapping->a_ops = &kernfs_aops; inode->i_op = &kernfs_iops; + inode->i_generation = kn->generation; set_default_inode_attr(inode, kn->mode); kernfs_refresh_inode(kn, inode); diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index a9b11b8..c5f0fa7 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -135,6 +135,7 @@ struct kernfs_node { umode_t mode; unsigned int ino; struct kernfs_iattrs *iattr; + u32 generation; }; /* @@ -170,6 +171,7 @@ struct kernfs_root { struct list_head supers; wait_queue_head_t deactivate_waitq; + atomic_t next_generation; }; struct kernfs_open_file { -- 2.9.3