litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'lib/spinlock_debug.c')

0 files changed, 0 insertions, 0 deletions

/* * linux/fs/pnode.c * * (C) Copyright IBM Corporation 2005. * Released under GPL v2. * Author : Ram Pai (linuxram@us.ibm.com) * */ #include <linux/mnt_namespace.h> #include <linux/mount.h> #include <linux/fs.h> #include "internal.h" #include "pnode.h" /* return the next shared peer mount of @p */ static inline struct mount *next_peer(struct mount *p) { return list_entry(p->mnt_share.next, struct mount, mnt_share); } static inline struct mount *first_slave(struct mount *p) { return list_entry(p->mnt_slave_list.next, struct mount, mnt_slave); } static inline struct mount *next_slave(struct mount *p) { return list_entry(p->mnt_slave.next, struct mount, mnt_slave); } static struct mount *get_peer_under_root(struct mount *mnt, struct mnt_namespace *ns, const struct path *root) { struct mount *m = mnt; do { /* Check the namespace first for optimization */ if (m->mnt_ns == ns && is_path_reachable(m, m->mnt.mnt_root, root)) return m; m = next_peer(m); } while (m != mnt); return NULL; } /* * Get ID of closest dominating peer group having a representative * under the given root. * * Caller must hold namespace_sem */ int get_dominating_id(struct mount *mnt, const struct path *root) { struct mount *m; for (m = mnt->mnt_master; m != NULL; m = m->mnt_master) { struct mount *d = get_peer_under_root(m, mnt->mnt_ns, root); if (d) return d->mnt_group_id; } return 0; } static int do_make_slave(struct mount *mnt) { struct mount *peer_mnt = mnt, *master = mnt->mnt_master; struct mount *slave_mnt; /* * slave 'mnt' to a peer mount that has the * same root dentry. If none is available then * slave it to anything that is available. */ while ((peer_mnt = next_peer(peer_mnt)) != mnt && peer_mnt->mnt.mnt_root != mnt->mnt.mnt_root) ; if (peer_mnt == mnt) { peer_mnt = next_peer(mnt); if (peer_mnt == mnt) peer_mnt = NULL; } if (IS_MNT_SHARED(mnt) && list_empty(&mnt->mnt_share)) mnt_release_group_id(mnt); list_del_init(&mnt->mnt_share); mnt->mnt_group_id = 0; if (peer_mnt) master = peer_mnt; if (master) { list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave) slave_mnt->mnt_master = master; list_move(&mnt->mnt_slave, &master->mnt_slave_list); list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev); INIT_LIST_HEAD(&mnt->mnt_slave_list); } else { struct list_head *p = &mnt->mnt_slave_list; while (!list_empty(p)) { slave_mnt = list_first_entry(p, struct mount, mnt_slave); list_del_init(&slave_mnt->mnt_slave); slave_mnt->mnt_master = NULL; } } mnt->mnt_master = master; CLEAR_MNT_SHARED(mnt); return 0; } /* * vfsmount lock must be held for write */ void change_mnt_propagation(struct mount *mnt, int type) { if (type == MS_SHARED) { set_mnt_shared(mnt); return; } do_make_slave(mnt); if (type != MS_SLAVE) { list_del_init(&mnt->mnt_slave); mnt->mnt_master = NULL; if (type == MS_UNBINDABLE) mnt->mnt.mnt_flags |= MNT_UNBINDABLE; else mnt->mnt.mnt_flags &= ~MNT_UNBINDABLE; } } /* * get the next mount in the propagation tree. * @m: the mount seen last * @origin: the original mount from where the tree walk initiated * * Note that peer groups form contiguous segments of slave lists. * We rely on that in get_source() to be able to find out if * vfsmount found while iterating with propagation_next() is * a peer of one we'd found earlier. */ static struct mount *propagation_next(struct mount *m, struct mount *origin) { /* are there any slaves of this mount? */ if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list)) return first_slave(m); while (1) { struct mount *master = m->mnt_master; if (master == origin->mnt_master) { struct mount *next = next_peer(m); return (next == origin) ? NULL : next; } else if (m->mnt_slave.next != &master->mnt_slave_list) return next_slave(m); /* back at master */ m = master; } } /* * return the source mount to be used for cloning * * @dest the current destination mount * @last_dest the last seen destination mount * @last_src the last seen source mount * @type return CL_SLAVE if the new mount has to be * cloned as a slave. */ static struct mount *get_source(struct mount *dest, struct mount *last_dest,


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