Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755719AbaDNVp2 (ORCPT ); Mon, 14 Apr 2014 17:45:28 -0400 Received: from mail-qg0-f41.google.com ([209.85.192.41]:62083 "EHLO mail-qg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755108AbaDNVoN (ORCPT ); Mon, 14 Apr 2014 17:44:13 -0400 From: Tejun Heo To: lizefan@huawei.com Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, john@johnmccutchan.com, rlove@rlove.org, eparis@parisplace.org, gregkh@linuxfoundation.org, serge.hallyn@ubuntu.com, lennart@poettering.net, kay@vrfy.org, Tejun Heo Subject: [PATCH 1/3] kernfs: implement kernfs_root->supers list Date: Mon, 14 Apr 2014 17:44:04 -0400 Message-Id: <1397511846-2904-2-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1397511846-2904-1-git-send-email-tj@kernel.org> References: <1397511846-2904-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, there's no way to find out which super_blocks are associated with a given kernfs_root. Let's implement it - the planned inotify extension to kernfs_notify() needs it. Make kernfs_super_info point back to the super_block and chain it at kernfs_root->supers. Signed-off-by: Tejun Heo Cc: Greg Kroah-Hartman --- fs/kernfs/dir.c | 1 + fs/kernfs/kernfs-internal.h | 5 +++++ fs/kernfs/mount.c | 11 +++++++++++ include/linux/kernfs.h | 4 ++++ 4 files changed, 21 insertions(+) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 78f3403..43aa979 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -711,6 +711,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops, return ERR_PTR(-ENOMEM); ida_init(&root->ino_ida); + INIT_LIST_HEAD(&root->supers); kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO, KERNFS_DIR); diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h index 8be13b2..dc84a3e 100644 --- a/fs/kernfs/kernfs-internal.h +++ b/fs/kernfs/kernfs-internal.h @@ -49,6 +49,8 @@ static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn) * mount.c */ struct kernfs_super_info { + struct super_block *sb; + /* * The root associated with this super_block. Each super_block is * identified by the root and ns it's associated with. @@ -62,6 +64,9 @@ struct kernfs_super_info { * an array and compare kernfs_node tag against every entry. */ const void *ns; + + /* anchored at kernfs_root->supers, protected by kernfs_mutex */ + struct list_head node; }; #define kernfs_info(SB) ((struct kernfs_super_info *)(SB->s_fs_info)) diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index 6a5f04a..f25a7c0 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -68,6 +68,7 @@ static int kernfs_fill_super(struct super_block *sb) struct inode *inode; struct dentry *root; + info->sb = sb; sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = SYSFS_MAGIC; @@ -166,12 +167,18 @@ struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, *new_sb_created = !sb->s_root; if (!sb->s_root) { + struct kernfs_super_info *info = kernfs_info(sb); + error = kernfs_fill_super(sb); if (error) { deactivate_locked_super(sb); return ERR_PTR(error); } sb->s_flags |= MS_ACTIVE; + + mutex_lock(&kernfs_mutex); + list_add(&info->node, &root->supers); + mutex_unlock(&kernfs_mutex); } return dget(sb->s_root); @@ -190,6 +197,10 @@ void kernfs_kill_sb(struct super_block *sb) struct kernfs_super_info *info = kernfs_info(sb); struct kernfs_node *root_kn = sb->s_root->d_fsdata; + mutex_lock(&kernfs_mutex); + list_del(&info->node); + mutex_unlock(&kernfs_mutex); + /* * Remove the superblock from fs_supers/s_instances * so we can't find it, before freeing kernfs_super_info. diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index b0122dc..589318b 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -144,6 +144,10 @@ struct kernfs_root { /* private fields, do not use outside kernfs proper */ struct ida ino_ida; struct kernfs_syscall_ops *syscall_ops; + + /* list of kernfs_super_info of this root, protected by kernfs_mutex */ + struct list_head supers; + wait_queue_head_t deactivate_waitq; }; -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/