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Commit 419148da authored by Al Viro's avatar Al Viro
Browse files

vfs: spread struct mount - attach_mnt/detach_mnt 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 315fc83e

fs/namespace.c

+22 −19
Original line number Diff line number Diff line
@@ -556,14 +556,14 @@ static void dentry_reset_mounted(struct dentry *dentry) 
/*

 * vfsmount lock must be held for write

 */

static void detach_mnt(struct vfsmount *mnt, struct path *old_path)

{

	old_path->dentry = mnt->mnt_mountpoint;

	old_path->mnt = mnt->mnt_parent;

	mnt->mnt_parent = mnt;

	mnt->mnt_mountpoint = mnt->mnt_root;

	list_del_init(&mnt->mnt_child);

	list_del_init(&mnt->mnt_hash);

static void detach_mnt(struct mount *mnt, struct path *old_path)

{

	old_path->dentry = mnt->mnt.mnt_mountpoint;

	old_path->mnt = mnt->mnt.mnt_parent;

	mnt->mnt.mnt_parent = &mnt->mnt;

	mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;

	list_del_init(&mnt->mnt.mnt_child);

	list_del_init(&mnt->mnt.mnt_hash);

	dentry_reset_mounted(old_path->dentry);

}
@@ -583,12 +583,12 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, 
/*

 * vfsmount lock must be held for write

 */

static void attach_mnt(struct vfsmount *mnt, struct path *path)

static void attach_mnt(struct mount *mnt, struct path *path)

{

	mnt_set_mountpoint(path->mnt, path->dentry, mnt);

	list_add_tail(&mnt->mnt_hash, mount_hashtable +

	mnt_set_mountpoint(path->mnt, path->dentry, &mnt->mnt);

	list_add_tail(&mnt->mnt.mnt_hash, mount_hashtable +

			hash(path->mnt, path->dentry));

	list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);

	list_add_tail(&mnt->mnt.mnt_child, &path->mnt->mnt_mounts);

}



static inline void __mnt_make_longterm(struct vfsmount *mnt)
@@ -1446,7 +1446,7 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry, 
				goto Enomem;

			br_write_lock(vfsmount_lock);

			list_add_tail(&q->mnt_list, &res->mnt_list);

			attach_mnt(q, &path);

			attach_mnt(real_mount(q), &path);

			br_write_unlock(vfsmount_lock);

		}

	}
@@ -1612,8 +1612,8 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt, 
			set_mnt_shared(&p->mnt);

	}

	if (parent_path) {

		detach_mnt(source_mnt, parent_path);

		attach_mnt(source_mnt, path);

		detach_mnt(real_mount(source_mnt), parent_path);

		attach_mnt(real_mount(source_mnt), path);

		touch_mnt_namespace(parent_path->mnt->mnt_ns);

	} else {

		mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
@@ -2600,6 +2600,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, 
		const char __user *, put_old)

{

	struct path new, old, parent_path, root_parent, root;

	struct mount *new_mnt, *root_mnt;

	int error;



	if (!capable(CAP_SYS_ADMIN))
@@ -2623,6 +2624,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, 
		goto out3;



	error = -EINVAL;

	new_mnt = real_mount(new.mnt);

	root_mnt = real_mount(root.mnt);

	if (IS_MNT_SHARED(old.mnt) ||

		IS_MNT_SHARED(new.mnt->mnt_parent) ||

		IS_MNT_SHARED(root.mnt->mnt_parent))
@@ -2651,12 +2654,12 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, 
	if (!is_path_reachable(old.mnt, old.dentry, &new))

		goto out4;

	br_write_lock(vfsmount_lock);

	detach_mnt(new.mnt, &parent_path);

	detach_mnt(root.mnt, &root_parent);

	detach_mnt(new_mnt, &parent_path);

	detach_mnt(root_mnt, &root_parent);

	/* mount old root on put_old */

	attach_mnt(root.mnt, &old);

	attach_mnt(root_mnt, &old);

	/* mount new_root on / */

	attach_mnt(new.mnt, &root_parent);

	attach_mnt(new_mnt, &root_parent);

	touch_mnt_namespace(current->nsproxy->mnt_ns);

	br_write_unlock(vfsmount_lock);

	chroot_fs_refs(&root, &new);