diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2025-06-17 21:35:22 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2025-06-29 19:03:37 -0400 |
| commit | 663206854f020ec6fc6bfd3d52f501a28ede1403 (patch) | |
| tree | 5d091baf6393554ab406892c1c184f984e7899a2 | |
| parent | dd5a4e1d640bf3542c4583491e6b91d25de3b760 (diff) | |
| download | random-663206854f02.tar.gz | |
copy_tree(): don't link the mounts via mnt_list
The only place that really needs to be adjusted is commit_tree() -
there we need to iterate through the copy and we might as well
use next_mnt() for that. However, in case when our tree has been
slid under something already mounted (propagation to a mountpoint
that already has something mounted on it or a 'beneath' move_mount)
we need to take care not to walk into the overmounting tree.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/mount.h | 3 | ||||
| -rw-r--r-- | fs/namespace.c | 60 | ||||
| -rw-r--r-- | fs/pnode.c | 3 |
3 files changed, 27 insertions, 39 deletions
diff --git a/fs/mount.h b/fs/mount.h index 08583428b10b55..97737051a8b9df 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -193,7 +193,7 @@ static inline bool mnt_ns_empty(const struct mnt_namespace *ns) return RB_EMPTY_ROOT(&ns->mounts); } -static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) +static inline void move_from_ns(struct mount *mnt) { struct mnt_namespace *ns = mnt->mnt_ns; WARN_ON(!mnt_ns_attached(mnt)); @@ -203,7 +203,6 @@ static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) ns->mnt_first_node = rb_next(&mnt->mnt_node); rb_erase(&mnt->mnt_node, &ns->mounts); RB_CLEAR_NODE(&mnt->mnt_node); - list_add_tail(&mnt->mnt_list, dt_list); } bool has_locked_children(struct mount *mnt, struct dentry *dentry); diff --git a/fs/namespace.c b/fs/namespace.c index 38a46b32413d02..bd6c7da901fcab 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1161,34 +1161,6 @@ static void mnt_add_to_ns(struct mnt_namespace *ns, struct mount *mnt) mnt_notify_add(mnt); } -/* - * vfsmount lock must be held for write - */ -static void commit_tree(struct mount *mnt) -{ - struct mount *parent = mnt->mnt_parent; - struct mount *m; - LIST_HEAD(head); - struct mnt_namespace *n = parent->mnt_ns; - - BUG_ON(parent == mnt); - - if (!mnt_ns_attached(mnt)) { - list_add_tail(&head, &mnt->mnt_list); - while (!list_empty(&head)) { - m = list_first_entry(&head, typeof(*m), mnt_list); - list_del(&m->mnt_list); - - mnt_add_to_ns(n, m); - } - n->nr_mounts += n->pending_mounts; - n->pending_mounts = 0; - } - - make_visible(mnt); - touch_mnt_namespace(n); -} - static struct mount *next_mnt(struct mount *p, struct mount *root) { struct list_head *next = p->mnt_mounts.next; @@ -1215,6 +1187,27 @@ static struct mount *skip_mnt_tree(struct mount *p) return p; } +/* + * vfsmount lock must be held for write + */ +static void commit_tree(struct mount *mnt) +{ + struct mnt_namespace *n = mnt->mnt_parent->mnt_ns; + + if (!mnt_ns_attached(mnt)) { + for (struct mount *m = mnt; m; m = next_mnt(m, mnt)) + if (unlikely(mnt_ns_attached(m))) + m = skip_mnt_tree(m); + else + mnt_add_to_ns(n, m); + n->nr_mounts += n->pending_mounts; + n->pending_mounts = 0; + } + + make_visible(mnt); + touch_mnt_namespace(n); +} + /** * vfs_create_mount - Create a mount for a configured superblock * @fc: The configuration context with the superblock attached @@ -1831,9 +1824,8 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how) for (p = mnt; p; p = next_mnt(p, mnt)) { p->mnt.mnt_flags |= MNT_UMOUNT; if (mnt_ns_attached(p)) - move_from_ns(p, &tmp_list); - else - list_move(&p->mnt_list, &tmp_list); + move_from_ns(p); + list_add_tail(&p->mnt_list, &tmp_list); } /* Hide the mounts from mnt_mounts */ @@ -2270,7 +2262,6 @@ struct mount *copy_tree(struct mount *src_root, struct dentry *dentry, list_add(&dst_mnt->mnt_expire, &src_mnt->mnt_expire); } - list_add_tail(&dst_mnt->mnt_list, &res->mnt_list); attach_mnt(dst_mnt, dst_parent, src_parent->mnt_mp); unlock_mount_hash(); } @@ -2686,12 +2677,9 @@ static int attach_recursive_mnt(struct mount *source_mnt, list_del_init(&source_mnt->mnt_expire); } else { if (source_mnt->mnt_ns) { - LIST_HEAD(head); - /* move from anon - the caller will destroy */ for (p = source_mnt; p; p = next_mnt(p, source_mnt)) - move_from_ns(p, &head); - list_del_init(&head); + move_from_ns(p); } } diff --git a/fs/pnode.c b/fs/pnode.c index cbf5f5746252d6..81f7599bdac4fc 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -449,7 +449,8 @@ static void umount_one(struct mount *m, struct list_head *to_umount) { m->mnt.mnt_flags |= MNT_UMOUNT; list_del_init(&m->mnt_child); - move_from_ns(m, to_umount); + move_from_ns(m); + list_add_tail(&m->mnt_list, to_umount); } static void remove_from_candidate_list(struct mount *m) |