vfs: now it can be done - make mnt_parent point to struct mount
Al Viro [Fri, 25 Nov 2011 03:19:58 +0000 (22:19 -0500)]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/dcache.c
fs/mount.h
fs/namei.c
fs/namespace.c
fs/pnode.c

index eef2d54..98b4875 100644 (file)
@@ -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;
index 5126c08..201dd61 100644 (file)
@@ -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);
index 89248bf..2e9110a 100644 (file)
@@ -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;
 }
 
index c6384bc..5e700c6 100644 (file)
@@ -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;
index 2ff4dfa..7fddc67 100644 (file)
@@ -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);