kernfs: remove KERNFS_REMOVED

[karo-tx-linux.git] / fs / kernfs / dir.c

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 1c9130a33048664a099398a6b751765535041496..7f8afc1d08f144d7e08f36ebf82fb3dce657f98b 100644 (file)
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -127,6 +127,7 @@ static void kernfs_unlink_sibling(struct kernfs_node *kn)
                kn->parent->dir.subdirs--;
 
        rb_erase(&kn->rb, &kn->parent->dir.children);
+       RB_CLEAR_NODE(&kn->rb);
 }
 
 /**
@@ -177,18 +178,16 @@ void kernfs_put_active(struct kernfs_node *kn)
 }
 
 /**
- *     kernfs_deactivate - deactivate kernfs_node
- *     @kn: kernfs_node to deactivate
+ * kernfs_drain - drain kernfs_node
+ * @kn: kernfs_node to drain
  *
- *     Deny new active references and drain existing ones.
+ * Drain existing usages.
  */
-static void kernfs_deactivate(struct kernfs_node *kn)
+static void kernfs_drain(struct kernfs_node *kn)
 {
        struct kernfs_root *root = kernfs_root(kn);
 
-       BUG_ON(!(kn->flags & KERNFS_REMOVED));
-
-       atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
+       WARN_ON_ONCE(atomic_read(&kn->active) >= 0);
 
        if (kernfs_lockdep(kn)) {
                rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
@@ -233,13 +232,15 @@ void kernfs_put(struct kernfs_node *kn)
                return;
        root = kernfs_root(kn);
  repeat:
-       /* Moving/renaming is always done while holding reference.
+       /*
+        * Moving/renaming is always done while holding reference.
         * kn->parent won't change beneath us.
         */
        parent = kn->parent;
 
-       WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
-            parent ? parent->name : "", kn->name);
+       WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
+                 "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
+                 parent ? parent->name : "", kn->name, atomic_read(&kn->active));
 
        if (kernfs_type(kn) == KERNFS_LINK)
                kernfs_put(kn->symlink.target_kn);
@@ -281,8 +282,8 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
        kn = dentry->d_fsdata;
        mutex_lock(&kernfs_mutex);
 
-       /* The kernfs node has been deleted */
-       if (kn->flags & KERNFS_REMOVED)
+       /* Force fresh lookup if removed */
+       if (kn->parent && RB_EMPTY_NODE(&kn->rb))
                goto out_bad;
 
        /* The kernfs node has been moved? */
@@ -350,11 +351,12 @@ struct kernfs_node *kernfs_new_node(struct kernfs_root *root, const char *name,
        kn->ino = ret;
 
        atomic_set(&kn->count, 1);
-       atomic_set(&kn->active, 0);
+       atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
+       RB_CLEAR_NODE(&kn->rb);
 
        kn->name = name;
        kn->mode = mode;
-       kn->flags = flags | KERNFS_REMOVED;
+       kn->flags = flags;
 
        return kn;
 
@@ -413,6 +415,8 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
        struct kernfs_iattrs *ps_iattr;
        int ret;
 
+       WARN_ON_ONCE(atomic_read(&parent->active) < 0);
+
        if (has_ns != (bool)kn->ns) {
                WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
                     has_ns ? "required" : "invalid", parent->name, kn->name);
@@ -422,9 +426,6 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
        if (kernfs_type(parent) != KERNFS_DIR)
                return -EINVAL;
 
-       if (parent->flags & KERNFS_REMOVED)
-               return -ENOENT;
-
        kn->hash = kernfs_name_hash(kn->name, kn->ns);
        kn->parent = parent;
        kernfs_get(parent);
@@ -441,8 +442,7 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn,
        }
 
        /* Mark the entry added into directory tree */
-       kn->flags &= ~KERNFS_REMOVED;
-
+       atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
        return 0;
 }
 
@@ -470,7 +470,7 @@ static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
         * Removal can be called multiple times on the same node.  Only the
         * first invocation is effective and puts the base ref.
         */
-       if (kn->flags & KERNFS_REMOVED)
+       if (atomic_read(&kn->active) < 0)
                return;
 
        if (kn->parent) {
@@ -484,7 +484,7 @@ static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
                }
        }
 
-       kn->flags |= KERNFS_REMOVED;
+       atomic_add(KN_DEACTIVATED_BIAS, &kn->active);
        kn->u.removed_list = acxt->removed;
        acxt->removed = kn;
 }
@@ -512,7 +512,7 @@ void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
 
                acxt->removed = kn->u.removed_list;
 
-               kernfs_deactivate(kn);
+               kernfs_drain(kn);
                kernfs_unmap_bin_file(kn);
                kernfs_put(kn);
        }
@@ -610,7 +610,7 @@ struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
                return ERR_PTR(-ENOMEM);
        }
 
-       kn->flags &= ~KERNFS_REMOVED;
+       atomic_sub(KN_DEACTIVATED_BIAS, &kn->active);
        kn->priv = priv;
        kn->dir.root = root;
 
@@ -662,9 +662,13 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
        kn->priv = priv;
 
        /* link in */
-       kernfs_addrm_start(&acxt);
-       rc = kernfs_add_one(&acxt, kn, parent);
-       kernfs_addrm_finish(&acxt);
+       rc = -ENOENT;
+       if (kernfs_get_active(parent)) {
+               kernfs_addrm_start(&acxt);
+               rc = kernfs_add_one(&acxt, kn, parent);
+               kernfs_addrm_finish(&acxt);
+               kernfs_put_active(parent);
+       }
 
        if (!rc)
                return kn;
@@ -899,27 +903,29 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
 {
        int error;
 
-       mutex_lock(&kernfs_mutex);
-
        error = -ENOENT;
-       if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
+       if (!kernfs_get_active(new_parent))
                goto out;
+       if (!kernfs_get_active(kn))
+               goto out_put_new_parent;
+
+       mutex_lock(&kernfs_mutex);
 
        error = 0;
        if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
            (strcmp(kn->name, new_name) == 0))
-               goto out;       /* nothing to rename */
+               goto out_unlock;        /* nothing to rename */
 
        error = -EEXIST;
        if (kernfs_find_ns(new_parent, new_name, new_ns))
-               goto out;
+               goto out_unlock;
 
        /* rename kernfs_node */
        if (strcmp(kn->name, new_name) != 0) {
                error = -ENOMEM;
                new_name = kstrdup(new_name, GFP_KERNEL);
                if (!new_name)
-                       goto out;
+                       goto out_unlock;
 
                if (kn->flags & KERNFS_STATIC_NAME)
                        kn->flags &= ~KERNFS_STATIC_NAME;
@@ -941,8 +947,12 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
        kernfs_link_sibling(kn);
 
        error = 0;
- out:
+out_unlock:
        mutex_unlock(&kernfs_mutex);
+       kernfs_put_active(kn);
+out_put_new_parent:
+       kernfs_put_active(new_parent);
+out:
        return error;
 }
 
@@ -962,8 +972,7 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns,
        struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
 {
        if (pos) {
-               int valid = !(pos->flags & KERNFS_REMOVED) &&
-                       pos->parent == parent && hash == pos->hash;
+               int valid = pos->parent == parent && hash == pos->hash;
                kernfs_put(pos);
                if (!valid)
                        pos = NULL;