From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753985AbaBOVhN (ORCPT ); Sat, 15 Feb 2014 16:37:13 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:33754 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753928AbaBOVhK (ORCPT ); Sat, 15 Feb 2014 16:37:10 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Al Viro Cc: "Serge E. Hallyn" , Linux-Fsdevel , Kernel Mailing List , Andy Lutomirski , Rob Landley , Linus Torvalds , Miklos Szeredi , Christoph Hellwig , Karel Zak , "J. Bruce Fields" References: <87a9kkax0j.fsf@xmission.com> <8761v7h2pt.fsf@tw-ebiederman.twitter.com> <87li281wx6.fsf_-_@xmission.com> <87ob28kqks.fsf_-_@xmission.com> Date: Sat, 15 Feb 2014 13:37:03 -0800 In-Reply-To: <87ob28kqks.fsf_-_@xmission.com> (Eric W. Biederman's message of "Sat, 15 Feb 2014 13:34:43 -0800") Message-ID: <87zjlsjbwg.fsf_-_@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1+q8rtJ0ipNytduty54CtskYDnP3KFSNXk= X-SA-Exim-Connect-IP: 98.207.154.105 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 3.0 KHOP_BIG_TO_CC Sent to 10+ recipients instaed of Bcc or a list * 1.5 XMNoVowels Alpha-numberic number with no vowels * -0.5 BAYES_05 BODY: Bayes spam probability is 1 to 5% * [score: 0.0190] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa04 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa04 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ***;Al Viro X-Spam-Relay-Country: Subject: [PATCH 04/11] vfs: Keep a list of mounts on a mount point X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 14:26:46 -0700) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To spot any possible problems call BUG if a mountpoint is put when it's list of mounts is not empty. Signed-off-by: Eric W. Biederman --- fs/mount.h | 2 ++ fs/namespace.c | 6 ++++++ 2 files changed, 8 insertions(+), 0 deletions(-) diff --git a/fs/mount.h b/fs/mount.h index 17d913d86add..50a72d46e7a6 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -21,6 +21,7 @@ struct mnt_pcp { struct mountpoint { struct list_head m_hash; struct dentry *m_dentry; + struct list_head m_list; int m_count; }; @@ -48,6 +49,7 @@ struct mount { struct mount *mnt_master; /* slave is on master->mnt_slave_list */ struct mnt_namespace *mnt_ns; /* containing namespace */ struct mountpoint *mnt_mp; /* where is it mounted */ + struct list_head mnt_mp_list; /* list mounts with the same mountpoint */ #ifdef CONFIG_FSNOTIFY struct hlist_head mnt_fsnotify_marks; __u32 mnt_fsnotify_mask; diff --git a/fs/namespace.c b/fs/namespace.c index 6dc23614d44d..33db9e95bd5c 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -195,6 +195,7 @@ static struct mount *alloc_vfsmnt(const char *name) INIT_LIST_HEAD(&mnt->mnt_share); INIT_LIST_HEAD(&mnt->mnt_slave_list); INIT_LIST_HEAD(&mnt->mnt_slave); + INIT_LIST_HEAD(&mnt->mnt_mp_list); #ifdef CONFIG_FSNOTIFY INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks); #endif @@ -695,6 +696,7 @@ static struct mountpoint *new_mountpoint(struct dentry *dentry) mp->m_dentry = dentry; mp->m_count = 1; list_add(&mp->m_hash, chain); + INIT_LIST_HEAD(&mp->m_list); return mp; } @@ -702,6 +704,7 @@ static void put_mountpoint(struct mountpoint *mp) { if (!--mp->m_count) { struct dentry *dentry = mp->m_dentry; + BUG_ON(!list_empty(&mp->m_list)); spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_MOUNTED; spin_unlock(&dentry->d_lock); @@ -748,6 +751,7 @@ static void detach_mnt(struct mount *mnt, struct path *old_path) mnt->mnt_mountpoint = mnt->mnt.mnt_root; list_del_init(&mnt->mnt_child); list_del_init(&mnt->mnt_hash); + list_del_init(&mnt->mnt_mp_list); put_mountpoint(mnt->mnt_mp); mnt->mnt_mp = NULL; } @@ -764,6 +768,7 @@ void mnt_set_mountpoint(struct mount *mnt, child_mnt->mnt_mountpoint = dget(mp->m_dentry); child_mnt->mnt_parent = mnt; child_mnt->mnt_mp = mp; + list_add_tail(&child_mnt->mnt_mp_list, &mp->m_list); } /* @@ -1246,6 +1251,7 @@ void umount_tree(struct mount *mnt, int how) p->mnt.mnt_flags |= MNT_SYNC_UMOUNT; list_del_init(&p->mnt_child); if (mnt_has_parent(p)) { + list_del_init(&p->mnt_mp_list); put_mountpoint(p->mnt_mp); /* move the reference to mountpoint into ->mnt_ex_mountpoint */ p->mnt_ex_mountpoint.dentry = p->mnt_mountpoint; -- 1.7.5.4