diff options
| -rw-r--r-- | fs/namespace.c | 64 |
1 files changed, 22 insertions, 42 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index c2ffa0f..65f9c0e 100644 --- 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 vfsmount *p, struct vfsmount *root) 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 vfsmount *old, struct dentry *root) /* 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 dentry *d, struct dentry *dentry) } } -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 vfsmount *mnt, struct dentry *dentry) 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 *nd, char *old_name, int recurse) 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 task_struct *tsk) 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); |