From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030248AbVKHCCP (ORCPT ); Mon, 7 Nov 2005 21:02:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030242AbVKHCB6 (ORCPT ); Mon, 7 Nov 2005 21:01:58 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:24781 "EHLO ZenIV.linux.org.uk") by vger.kernel.org with ESMTP id S965183AbVKHCBg (ORCPT ); Mon, 7 Nov 2005 21:01:36 -0500 To: torvalds@osdl.org Subject: [PATCH 8/18] mount expiry fixes Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linuxram@us.ibm.com Message-Id: From: Al Viro Date: Tue, 08 Nov 2005 02:01:31 +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org From: Ram Pai Date: 1131401842 -0500 1) cleans up the ugliness in may_umount_tree() 2) fixes a bug in do_loopback(). after cloning a tree, do_loopback() unlinks only the topmost mount of the cloned tree, leaving behind the children mounts on their corresponding expiry list. Signed-off-by: Ram Pai (linuxram@us.ibm.com) Signed-off-by: Al Viro --- fs/namespace.c | 64 +++++++++++++++++++------------------------------------- 1 files changed, 22 insertions(+), 42 deletions(-) dff96a6036a64c1cc16161d622db76239d4172b5 diff --git a/fs/namespace.c b/fs/namespace.c --- a/fs/namespace.c +++ b/fs/namespace.c @@ -27,6 +27,8 @@ extern int __init init_rootfs(void); +#define CL_EXPIRE 0x01 + #ifdef CONFIG_SYSFS extern int __init sysfs_init(void); #else @@ -165,7 +167,8 @@ static struct vfsmount *next_mnt(struct return list_entry(next, struct vfsmount, mnt_child); } -static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root) +static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, + int flag) { struct super_block *sb = old->mnt_sb; struct vfsmount *mnt = alloc_vfsmnt(old->mnt_devname); @@ -181,10 +184,12 @@ static struct vfsmount *clone_mnt(struct /* stick the duplicate mount on the same expiry list * as the original if that was on one */ - spin_lock(&vfsmount_lock); - if (!list_empty(&old->mnt_expire)) - list_add(&mnt->mnt_expire, &old->mnt_expire); - spin_unlock(&vfsmount_lock); + if (flag & CL_EXPIRE) { + spin_lock(&vfsmount_lock); + if (!list_empty(&old->mnt_expire)) + list_add(&mnt->mnt_expire, &old->mnt_expire); + spin_unlock(&vfsmount_lock); + } } return mnt; } @@ -331,36 +336,14 @@ struct seq_operations mounts_op = { */ int may_umount_tree(struct vfsmount *mnt) { - struct list_head *next; - struct vfsmount *this_parent = mnt; - int actual_refs; - int minimum_refs; + int actual_refs = 0; + int minimum_refs = 0; + struct vfsmount *p; spin_lock(&vfsmount_lock); - actual_refs = atomic_read(&mnt->mnt_count); - minimum_refs = 2; -repeat: - next = this_parent->mnt_mounts.next; -resume: - while (next != &this_parent->mnt_mounts) { - struct vfsmount *p = - list_entry(next, struct vfsmount, mnt_child); - - next = next->next; - + for (p = mnt; p; p = next_mnt(p, mnt)) { actual_refs += atomic_read(&p->mnt_count); minimum_refs += 2; - - if (!list_empty(&p->mnt_mounts)) { - this_parent = p; - goto repeat; - } - } - - if (this_parent != mnt) { - next = this_parent->mnt_child.next; - this_parent = this_parent->mnt_parent; - goto resume; } spin_unlock(&vfsmount_lock); @@ -596,12 +579,13 @@ static int lives_below_in_same_fs(struct } } -static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry) +static struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, + int flag) { struct vfsmount *res, *p, *q, *r, *s; struct nameidata nd; - res = q = clone_mnt(mnt, dentry); + res = q = clone_mnt(mnt, dentry, flag); if (!q) goto Enomem; q->mnt_mountpoint = mnt->mnt_mountpoint; @@ -619,7 +603,7 @@ static struct vfsmount *copy_tree(struct p = s; nd.mnt = q; nd.dentry = p->mnt_mountpoint; - q = clone_mnt(p, p->mnt_root); + q = clone_mnt(p, p->mnt_root, flag); if (!q) goto Enomem; spin_lock(&vfsmount_lock); @@ -701,18 +685,13 @@ static int do_loopback(struct nameidata err = -ENOMEM; if (recurse) - mnt = copy_tree(old_nd.mnt, old_nd.dentry); + mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0); else - mnt = clone_mnt(old_nd.mnt, old_nd.dentry); + mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0); if (!mnt) goto out; - /* stop bind mounts from expiring */ - spin_lock(&vfsmount_lock); - list_del_init(&mnt->mnt_expire); - spin_unlock(&vfsmount_lock); - err = graft_tree(mnt, nd); if (err) { LIST_HEAD(umount_list); @@ -1155,7 +1134,8 @@ int copy_namespace(int flags, struct tas down_write(&tsk->namespace->sem); /* First pass: copy the tree topology */ - new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root); + new_ns->root = copy_tree(namespace->root, namespace->root->mnt_root, + CL_EXPIRE); if (!new_ns->root) { up_write(&tsk->namespace->sem); kfree(new_ns);