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Commit e3197d83 authored by Al Viro's avatar Al Viro
Browse files

saner umount_tree()/release_mounts(), part 1 



global list of release_mounts() fodder, protected by namespace_sem;
eventually, all umount_tree() callers will use it as kill list.
Helper picking the contents of that list, releasing namespace_sem
and doing release_mounts() on what it got.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 84d17192

fs/namespace.c

+13 −4
Original line number Diff line number Diff line
@@ -1119,6 +1119,8 @@ int may_umount(struct vfsmount *mnt) 


EXPORT_SYMBOL(may_umount);



static LIST_HEAD(unmounted);	/* protected by namespace_sem */



void release_mounts(struct list_head *head)

{

	struct mount *mnt;
@@ -1143,6 +1145,14 @@ void release_mounts(struct list_head *head) 
	}

}



static void namespace_unlock(void)

{

	LIST_HEAD(head);

	list_splice_init(&unmounted, &head);

	up_write(&namespace_sem);

	release_mounts(&head);

}



/*

 * vfsmount lock must be held for write

 * namespace_sem must be held for write
@@ -1252,17 +1262,16 @@ static int do_umount(struct mount *mnt, int flags) 
	event++;



	if (!(flags & MNT_DETACH))

		shrink_submounts(mnt, &umount_list);

		shrink_submounts(mnt, &unmounted);



	retval = -EBUSY;

	if (flags & MNT_DETACH || !propagate_mount_busy(mnt, 2)) {

		if (!list_empty(&mnt->mnt_list))

			umount_tree(mnt, 1, &umount_list);

			umount_tree(mnt, 1, &unmounted);

		retval = 0;

	}

	br_write_unlock(&vfsmount_lock);

	up_write(&namespace_sem);

	release_mounts(&umount_list);

	namespace_unlock();

	return retval;

}