diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 87 |
1 files changed, 42 insertions, 45 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index d82910f33dc4..a7fd9682bcf9 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -132,16 +132,6 @@ EXPORT_SYMBOL_GPL(fs_kobj); */ __cacheline_aligned_in_smp DEFINE_SEQLOCK(mount_lock); -static inline struct mnt_namespace *node_to_mnt_ns(const struct rb_node *node) -{ - struct ns_common *ns; - - if (!node) - return NULL; - ns = rb_entry(node, struct ns_common, ns_tree_node); - return container_of(ns, struct mnt_namespace, ns); -} - static void mnt_ns_release(struct mnt_namespace *ns) { /* keep alive for {list,stat}mount() */ @@ -151,7 +141,8 @@ static void mnt_ns_release(struct mnt_namespace *ns) kfree(ns); } } -DEFINE_FREE(mnt_ns_release, struct mnt_namespace *, if (_T) mnt_ns_release(_T)) +DEFINE_FREE(mnt_ns_release, struct mnt_namespace *, + if (!IS_ERR(_T)) mnt_ns_release(_T)) static void mnt_ns_release_rcu(struct rcu_head *rcu) { @@ -1345,26 +1336,12 @@ static void delayed_mntput(struct work_struct *unused) } static DECLARE_DELAYED_WORK(delayed_mntput_work, delayed_mntput); -static void mntput_no_expire(struct mount *mnt) +static void noinline mntput_no_expire_slowpath(struct mount *mnt) { LIST_HEAD(list); int count; - rcu_read_lock(); - if (likely(READ_ONCE(mnt->mnt_ns))) { - /* - * Since we don't do lock_mount_hash() here, - * ->mnt_ns can change under us. However, if it's - * non-NULL, then there's a reference that won't - * be dropped until after an RCU delay done after - * turning ->mnt_ns NULL. So if we observe it - * non-NULL under rcu_read_lock(), the reference - * we are dropping is not the final one. - */ - mnt_add_count(mnt, -1); - rcu_read_unlock(); - return; - } + VFS_BUG_ON(mnt->mnt_ns); lock_mount_hash(); /* * make sure that if __legitimize_mnt() has not seen us grab @@ -1415,6 +1392,26 @@ static void mntput_no_expire(struct mount *mnt) cleanup_mnt(mnt); } +static void mntput_no_expire(struct mount *mnt) +{ + rcu_read_lock(); + if (likely(READ_ONCE(mnt->mnt_ns))) { + /* + * Since we don't do lock_mount_hash() here, + * ->mnt_ns can change under us. However, if it's + * non-NULL, then there's a reference that won't + * be dropped until after an RCU delay done after + * turning ->mnt_ns NULL. So if we observe it + * non-NULL under rcu_read_lock(), the reference + * we are dropping is not the final one. + */ + mnt_add_count(mnt, -1); + rcu_read_unlock(); + return; + } + mntput_no_expire_slowpath(mnt); +} + void mntput(struct vfsmount *mnt) { if (mnt) { @@ -5454,11 +5451,11 @@ static int statmount_string(struct kstatmount *s, u64 flag) ret = statmount_sb_source(s, seq); break; case STATMOUNT_MNT_UIDMAP: - sm->mnt_uidmap = start; + offp = &sm->mnt_uidmap; ret = statmount_mnt_uidmap(s, seq); break; case STATMOUNT_MNT_GIDMAP: - sm->mnt_gidmap = start; + offp = &sm->mnt_gidmap; ret = statmount_mnt_gidmap(s, seq); break; default: @@ -5736,7 +5733,7 @@ static int copy_mnt_id_req(const struct mnt_id_req __user *req, ret = copy_struct_from_user(kreq, sizeof(*kreq), req, usize); if (ret) return ret; - if (kreq->spare != 0) + if (kreq->mnt_ns_fd != 0 && kreq->mnt_ns_id) return -EINVAL; /* The first valid unique mount id is MNT_UNIQUE_ID_OFFSET + 1. */ if (kreq->mnt_id <= MNT_UNIQUE_ID_OFFSET) @@ -5753,16 +5750,14 @@ static struct mnt_namespace *grab_requested_mnt_ns(const struct mnt_id_req *kreq { struct mnt_namespace *mnt_ns; - if (kreq->mnt_ns_id && kreq->spare) - return ERR_PTR(-EINVAL); - - if (kreq->mnt_ns_id) - return lookup_mnt_ns(kreq->mnt_ns_id); - - if (kreq->spare) { + if (kreq->mnt_ns_id) { + mnt_ns = lookup_mnt_ns(kreq->mnt_ns_id); + if (!mnt_ns) + return ERR_PTR(-ENOENT); + } else if (kreq->mnt_ns_fd) { struct ns_common *ns; - CLASS(fd, f)(kreq->spare); + CLASS(fd, f)(kreq->mnt_ns_fd); if (fd_empty(f)) return ERR_PTR(-EBADF); @@ -5774,11 +5769,12 @@ static struct mnt_namespace *grab_requested_mnt_ns(const struct mnt_id_req *kreq return ERR_PTR(-EINVAL); mnt_ns = to_mnt_ns(ns); + refcount_inc(&mnt_ns->passive); } else { mnt_ns = current->nsproxy->mnt_ns; + refcount_inc(&mnt_ns->passive); } - refcount_inc(&mnt_ns->passive); return mnt_ns; } @@ -5801,8 +5797,8 @@ SYSCALL_DEFINE4(statmount, const struct mnt_id_req __user *, req, return ret; ns = grab_requested_mnt_ns(&kreq); - if (!ns) - return -ENOENT; + if (IS_ERR(ns)) + return PTR_ERR(ns); if (kreq.mnt_ns_id && (ns != current->nsproxy->mnt_ns) && !ns_capable_noaudit(ns->user_ns, CAP_SYS_ADMIN)) @@ -5912,8 +5908,8 @@ static void __free_klistmount_free(const struct klistmount *kls) static inline int prepare_klistmount(struct klistmount *kls, struct mnt_id_req *kreq, size_t nr_mnt_ids) { - u64 last_mnt_id = kreq->param; + struct mnt_namespace *ns; /* The first valid unique mount id is MNT_UNIQUE_ID_OFFSET + 1. */ if (last_mnt_id != 0 && last_mnt_id <= MNT_UNIQUE_ID_OFFSET) @@ -5927,9 +5923,10 @@ static inline int prepare_klistmount(struct klistmount *kls, struct mnt_id_req * if (!kls->kmnt_ids) return -ENOMEM; - kls->ns = grab_requested_mnt_ns(kreq); - if (!kls->ns) - return -ENOENT; + ns = grab_requested_mnt_ns(kreq); + if (IS_ERR(ns)) + return PTR_ERR(ns); + kls->ns = ns; kls->mnt_parent_id = kreq->mnt_id; return 0; |