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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: Al Viro <viro@zeniv.linux.org.uk>
hifive-unleashed-5.1
Al Viro 2013-03-16 14:35:16 -04:00
parent 84d17192d2
commit e3197d83d6
1 changed files with 13 additions and 4 deletions
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17
fs/namespace.c
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@ -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;
}