vfs: now it can be done - make mnt_parent point to struct mount (0714a533) · Commits · 戴 / test

fs/dcache.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -2452,6 +2452,7 @@ static int prepend_path(const struct path *path,
		{
		struct dentry *dentry = path->dentry;
		struct vfsmount *vfsmnt = path->mnt;
		struct mount *mnt = real_mount(vfsmnt);
		bool slash = false;
		int error = 0;

		@@ -2460,12 +2461,12 @@ static int prepend_path(const struct path *path,
		struct dentry * parent;

		if (dentry == vfsmnt->mnt_root \|\| IS_ROOT(dentry)) {
		struct mount *mnt = real_mount(vfsmnt);
		/* Global root? */
		if (!mnt_has_parent(mnt))
		goto global_root;
		dentry = vfsmnt->mnt_mountpoint;
		vfsmnt = mnt->mnt_parent;
		dentry = mnt->mnt.mnt_mountpoint;
		mnt = mnt->mnt_parent;
		vfsmnt = &mnt->mnt;
		continue;
		}
		parent = dentry->d_parent;

fs/mount.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -2,7 +2,7 @@

		struct mount {
		struct list_head mnt_hash;
		struct vfsmount *mnt_parent;
		struct mount *mnt_parent;
		struct vfsmount mnt;
		};

		@@ -13,7 +13,7 @@ static inline struct mount real_mount(struct vfsmount mnt)

		static inline int mnt_has_parent(struct mount *mnt)
		{
		return &mnt->mnt != mnt->mnt_parent;
		return mnt != mnt->mnt_parent;
		}

		extern struct mount __lookup_mnt(struct vfsmount , struct dentry *, int);

fs/namei.c

+13 −11

Original line number	Diff line number	Diff line
		@@ -677,36 +677,38 @@ follow_link(struct path link, struct nameidata nd, void **p)

		static int follow_up_rcu(struct path *path)
		{
		struct vfsmount *parent;
		struct mount *mnt = real_mount(path->mnt);
		struct mount *parent;
		struct dentry *mountpoint;

		parent = real_mount(path->mnt)->mnt_parent;
		if (parent == path->mnt)
		parent = mnt->mnt_parent;
		if (&parent->mnt == path->mnt)
		return 0;
		mountpoint = path->mnt->mnt_mountpoint;
		mountpoint = mnt->mnt.mnt_mountpoint;
		path->dentry = mountpoint;
		path->mnt = parent;
		path->mnt = &parent->mnt;
		return 1;
		}

		int follow_up(struct path *path)
		{
		struct vfsmount *parent;
		struct mount *mnt = real_mount(path->mnt);
		struct mount *parent;
		struct dentry *mountpoint;

		br_read_lock(vfsmount_lock);
		parent = real_mount(path->mnt)->mnt_parent;
		if (parent == path->mnt) {
		parent = mnt->mnt_parent;
		if (&parent->mnt == path->mnt) {
		br_read_unlock(vfsmount_lock);
		return 0;
		}
		mntget(parent);
		mountpoint = dget(path->mnt->mnt_mountpoint);
		mntget(&parent->mnt);
		mountpoint = dget(mnt->mnt.mnt_mountpoint);
		br_read_unlock(vfsmount_lock);
		dput(path->dentry);
		path->dentry = mountpoint;
		mntput(path->mnt);
		path->mnt = parent;
		path->mnt = &parent->mnt;
		return 1;
		}

fs/namespace.c

+26 −26

Original line number	Diff line number	Diff line
		@@ -476,7 +476,7 @@ struct mount __lookup_mnt(struct vfsmount mnt, struct dentry *dentry,
		if (tmp == head)
		break;
		p = list_entry(tmp, struct mount, mnt_hash);
		if (p->mnt_parent == mnt && p->mnt.mnt_mountpoint == dentry) {
		if (&p->mnt_parent->mnt == mnt && p->mnt.mnt_mountpoint == dentry) {
		found = p;
		break;
		}
		@@ -558,8 +558,8 @@ static void dentry_reset_mounted(struct dentry *dentry)
		static void detach_mnt(struct mount mnt, struct path old_path)
		{
		old_path->dentry = mnt->mnt.mnt_mountpoint;
		old_path->mnt = mnt->mnt_parent;
		mnt->mnt_parent = &mnt->mnt;
		old_path->mnt = &mnt->mnt_parent->mnt;
		mnt->mnt_parent = mnt;
		mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
		list_del_init(&mnt->mnt.mnt_child);
		list_del_init(&mnt->mnt_hash);
		@@ -572,7 +572,7 @@ static void detach_mnt(struct mount mnt, struct path old_path)
		void mnt_set_mountpoint(struct vfsmount mnt, struct dentry dentry,
		struct mount *child_mnt)
		{
		child_mnt->mnt_parent = mntget(mnt);
		child_mnt->mnt_parent = real_mount(mntget(mnt));
		child_mnt->mnt.mnt_mountpoint = dget(dentry);
		spin_lock(&dentry->d_lock);
		dentry->d_flags \|= DCACHE_MOUNTED;
		@@ -610,12 +610,12 @@ static inline void __mnt_make_shortterm(struct vfsmount *mnt)
		*/
		static void commit_tree(struct mount *mnt)
		{
		struct vfsmount *parent = mnt->mnt_parent;
		struct mount *parent = mnt->mnt_parent;
		struct vfsmount *m;
		LIST_HEAD(head);
		struct mnt_namespace *n = parent->mnt_ns;
		struct mnt_namespace *n = parent->mnt.mnt_ns;

		BUG_ON(parent == &mnt->mnt);
		BUG_ON(parent == mnt);

		list_add_tail(&head, &mnt->mnt.mnt_list);
		list_for_each_entry(m, &head, mnt_list) {
		@@ -626,8 +626,8 @@ static void commit_tree(struct mount *mnt)
		list_splice(&head, n->list.prev);

		list_add_tail(&mnt->mnt_hash, mount_hashtable +
		hash(parent, mnt->mnt.mnt_mountpoint));
		list_add_tail(&mnt->mnt.mnt_child, &parent->mnt_mounts);
		hash(&parent->mnt, mnt->mnt.mnt_mountpoint));
		list_add_tail(&mnt->mnt.mnt_child, &parent->mnt.mnt_mounts);
		touch_mnt_namespace(n);
		}

		@@ -639,9 +639,9 @@ static struct mount next_mnt(struct mount p, struct vfsmount *root)
		if (&p->mnt == root)
		return NULL;
		next = p->mnt.mnt_child.next;
		if (next != &p->mnt_parent->mnt_mounts)
		if (next != &p->mnt_parent->mnt.mnt_mounts)
		break;
		p = real_mount(p->mnt_parent);
		p = p->mnt_parent;
		}
		}
		return list_entry(next, struct mount, mnt.mnt_child);
		@@ -682,7 +682,7 @@ vfs_kern_mount(struct file_system_type type, int flags, const char name, void
		mnt->mnt.mnt_root = root;
		mnt->mnt.mnt_sb = root->d_sb;
		mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
		mnt->mnt_parent = &mnt->mnt;
		mnt->mnt_parent = mnt;
		return &mnt->mnt;
		}
		EXPORT_SYMBOL_GPL(vfs_kern_mount);
		@@ -710,7 +710,7 @@ static struct mount clone_mnt(struct mount old, struct dentry *root,
		mnt->mnt.mnt_sb = sb;
		mnt->mnt.mnt_root = dget(root);
		mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
		mnt->mnt_parent = &mnt->mnt;
		mnt->mnt_parent = mnt;

		if (flag & CL_SLAVE) {
		list_add(&mnt->mnt.mnt_slave, &old->mnt.mnt_slave_list);
		@@ -1027,7 +1027,7 @@ static int show_mountinfo(struct seq_file m, void v)
		struct path root = p->root;
		int err = 0;

		seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, r->mnt_parent->mnt_id,
		seq_printf(m, "%i %i %u:%u ", mnt->mnt_id, r->mnt_parent->mnt.mnt_id,
		MAJOR(sb->s_dev), MINOR(sb->s_dev));
		if (sb->s_op->show_path)
		err = sb->s_op->show_path(m, mnt);
		@@ -1202,9 +1202,9 @@ void release_mounts(struct list_head *head)

		br_write_lock(vfsmount_lock);
		dentry = mnt->mnt.mnt_mountpoint;
		m = mnt->mnt_parent;
		m = &mnt->mnt_parent->mnt;
		mnt->mnt.mnt_mountpoint = mnt->mnt.mnt_root;
		mnt->mnt_parent = &mnt->mnt;
		mnt->mnt_parent = mnt;
		m->mnt_ghosts--;
		br_write_unlock(vfsmount_lock);
		dput(dentry);
		@@ -1237,7 +1237,7 @@ void umount_tree(struct mount mnt, int propagate, struct list_head kill)
		__mnt_make_shortterm(&p->mnt);
		list_del_init(&p->mnt.mnt_child);
		if (mnt_has_parent(p)) {
		p->mnt_parent->mnt_ghosts++;
		p->mnt_parent->mnt.mnt_ghosts++;
		dentry_reset_mounted(p->mnt.mnt_mountpoint);
		}
		change_mnt_propagation(p, MS_PRIVATE);
		@@ -1435,9 +1435,9 @@ struct mount copy_tree(struct mount mnt, struct dentry *dentry,
		s = skip_mnt_tree(s);
		continue;
		}
		while (p != real_mount(s->mnt_parent)) {
		p = real_mount(p->mnt_parent);
		q = real_mount(q->mnt_parent);
		while (p != s->mnt_parent) {
		p = p->mnt_parent;
		q = q->mnt_parent;
		}
		p = s;
		path.mnt = &q->mnt;
		@@ -1899,7 +1899,7 @@ static int do_move_mount(struct path path, char old_name)
		/*
		* Don't move a mount residing in a shared parent.
		*/
		if (IS_MNT_SHARED(old->mnt_parent))
		if (IS_MNT_SHARED(&old->mnt_parent->mnt))
		goto out1;
		/*
		* Don't move a mount tree containing unbindable mounts to a destination
		@@ -1909,7 +1909,7 @@ static int do_move_mount(struct path path, char old_name)
		tree_contains_unbindable(old))
		goto out1;
		err = -ELOOP;
		for (p = real_mount(path->mnt); mnt_has_parent(p); p = real_mount(p->mnt_parent))
		for (p = real_mount(path->mnt); mnt_has_parent(p); p = p->mnt_parent)
		if (p == old)
		goto out1;

		@@ -2159,7 +2159,7 @@ resume:
		*/
		if (this_parent != parent) {
		next = this_parent->mnt.mnt_child.next;
		this_parent = real_mount(this_parent->mnt_parent);
		this_parent = this_parent->mnt_parent;
		goto resume;
		}
		return found;
		@@ -2565,7 +2565,7 @@ bool is_path_reachable(struct mount mnt, struct dentry dentry,
		{
		while (&mnt->mnt != root->mnt && mnt_has_parent(mnt)) {
		dentry = mnt->mnt.mnt_mountpoint;
		mnt = real_mount(mnt->mnt_parent);
		mnt = mnt->mnt_parent;
		}
		return &mnt->mnt == root->mnt && is_subdir(dentry, root->dentry);
		}
		@@ -2636,8 +2636,8 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
		new_mnt = real_mount(new.mnt);
		root_mnt = real_mount(root.mnt);
		if (IS_MNT_SHARED(old.mnt) \|\|
		IS_MNT_SHARED(new_mnt->mnt_parent) \|\|
		IS_MNT_SHARED(root_mnt->mnt_parent))
		IS_MNT_SHARED(&new_mnt->mnt_parent->mnt) \|\|
		IS_MNT_SHARED(&root_mnt->mnt_parent->mnt))
		goto out4;
		if (!check_mnt(root.mnt) \|\| !check_mnt(new.mnt))
		goto out4;

fs/pnode.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -292,10 +292,10 @@ int propagate_mount_busy(struct mount *mnt, int refcnt)
		{
		struct vfsmount *m;
		struct mount *child;
		struct vfsmount *parent = mnt->mnt_parent;
		struct mount *parent = mnt->mnt_parent;
		int ret = 0;

		if (&mnt->mnt == parent)
		if (mnt == parent)
		return do_refcount_check(mnt, refcnt);

		/*
		@@ -306,8 +306,8 @@ int propagate_mount_busy(struct mount *mnt, int refcnt)
		if (!list_empty(&mnt->mnt.mnt_mounts) \|\| do_refcount_check(mnt, refcnt))
		return 1;

		for (m = propagation_next(parent, parent); m;
		m = propagation_next(m, parent)) {
		for (m = propagation_next(&parent->mnt, &parent->mnt); m;
		m = propagation_next(m, &parent->mnt)) {
		child = __lookup_mnt(m, mnt->mnt.mnt_mountpoint, 0);
		if (child && list_empty(&child->mnt.mnt_mounts) &&
		(ret = do_refcount_check(child, 1)))
		@@ -322,13 +322,13 @@ int propagate_mount_busy(struct mount *mnt, int refcnt)
		*/
		static void __propagate_umount(struct mount *mnt)
		{
		struct vfsmount *parent = mnt->mnt_parent;
		struct mount *parent = mnt->mnt_parent;
		struct vfsmount *m;

		BUG_ON(parent == &mnt->mnt);
		BUG_ON(parent == mnt);

		for (m = propagation_next(parent, parent); m;
		m = propagation_next(m, parent)) {
		for (m = propagation_next(&parent->mnt, &parent->mnt); m;
		m = propagation_next(m, &parent->mnt)) {

		struct mount *child = __lookup_mnt(m,
		mnt->mnt.mnt_mountpoint, 0);

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