From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eric W. Biederman" Subject: [PATCH review 06/19] mnt: Delay removal from the mount hash. Date: Thu, 2 Apr 2015 20:56:10 -0500 Message-ID: <1428026183-14879-6-git-send-email-ebiederm__10369.7099876173$1428026479$gmane$org@xmission.com> References: <87a8yqou41.fsf_-_@x220.int.ebiederm.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <87a8yqou41.fsf_-_-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Linux Containers Cc: Andrey Vagin , Richard Weinberger , Andy Lutomirski , Al Viro , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jann Horn , Omar Sandoval , Willy Tarreau List-Id: containers.vger.kernel.org - Modify __lookup_mnt_hash_last to ignore mounts that have MNT_UMOUNTED set. - Don't remove mounts from the mount hash table in propogate_umount - Don't remove mounts from the mount hash table in umount_tree before the entire list of mounts to be umounted is selected. - Remove mounts from the mount hash table as the last thing that happens in the case where a mount has a parent in umount_tree. Mounts without parents are not hashed (by definition). This paves the way for delaying removal from the mount hash table even farther and fixing the MNT_LOCKED vs MNT_DETACH issue. Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Signed-off-by: "Eric W. Biederman" --- fs/namespace.c | 13 ++++++++----- fs/pnode.c | 1 - 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index d1708147eb45..083e3401a808 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -632,14 +632,17 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) */ struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry) { - struct mount *p, *res; - res = p = __lookup_mnt(mnt, dentry); + struct mount *p, *res = NULL; + p = __lookup_mnt(mnt, dentry); if (!p) goto out; + if (!(p->mnt.mnt_flags & MNT_UMOUNT)) + res = p; hlist_for_each_entry_continue(p, mnt_hash) { if (&p->mnt_parent->mnt != mnt || p->mnt_mountpoint != dentry) break; - res = p; + if (!(p->mnt.mnt_flags & MNT_UMOUNT)) + res = p; } out: return res; @@ -1336,9 +1339,8 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) list_move(&p->mnt_list, &tmp_list); } - /* Hide the mounts from lookup_mnt and mnt_mounts */ + /* Hide the mounts from mnt_mounts */ list_for_each_entry(p, &tmp_list, mnt_list) { - hlist_del_init_rcu(&p->mnt_hash); list_del_init(&p->mnt_child); } @@ -1365,6 +1367,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) p->mnt_mountpoint = p->mnt.mnt_root; p->mnt_parent = p; p->mnt_mp = NULL; + hlist_del_init_rcu(&p->mnt_hash); } change_mnt_propagation(p, MS_PRIVATE); } diff --git a/fs/pnode.c b/fs/pnode.c index ac3aa0d43b90..c27ae38ee250 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -383,7 +383,6 @@ static void __propagate_umount(struct mount *mnt) */ if (child && list_empty(&child->mnt_mounts)) { list_del_init(&child->mnt_child); - hlist_del_init_rcu(&child->mnt_hash); child->mnt.mnt_flags |= MNT_UMOUNT; list_move_tail(&child->mnt_list, &mnt->mnt_list); } -- 2.2.1