[PATCH] count ghost references to vfsmounts
make propagate_mount_busy() exclude references from the vfsmounts
that had been isolated by umount_tree() and are just waiting for
release_mounts() to dispose of their ->mnt_parent/->mnt_mountpoint.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index 6324dfc..c175218 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -548,6 +548,7 @@
m = mnt->mnt_parent;
mnt->mnt_mountpoint = mnt->mnt_root;
mnt->mnt_parent = mnt;
+ m->mnt_ghosts--;
spin_unlock(&vfsmount_lock);
dput(dentry);
mntput(m);
@@ -572,8 +573,10 @@
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
list_del_init(&p->mnt_child);
- if (p->mnt_parent != p)
+ if (p->mnt_parent != p) {
+ p->mnt_parent->mnt_ghosts++;
p->mnt_mountpoint->d_mounted--;
+ }
change_mnt_propagation(p, MS_PRIVATE);
}
}
diff --git a/fs/pnode.c b/fs/pnode.c
index 05ba692..1d8f544 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -225,7 +225,7 @@
*/
static inline int do_refcount_check(struct vfsmount *mnt, int count)
{
- int mycount = atomic_read(&mnt->mnt_count);
+ int mycount = atomic_read(&mnt->mnt_count) - mnt->mnt_ghosts;
return (mycount > count);
}
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 6d3047d..dac5e67 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -61,6 +61,7 @@
atomic_t mnt_count;
int mnt_expiry_mark; /* true if marked for expiry */
int mnt_pinned;
+ int mnt_ghosts;
};
static inline struct vfsmount *mntget(struct vfsmount *mnt)
