#endif
}
-static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
-{
- if (!kn)
- return strscpy(buf, "(null)", buflen);
-
- return strscpy(buf, rcu_access_pointer(kn->__parent) ? kn->name : "/", buflen);
-}
-
/* kernfs_node_depth - compute depth from @from to @to */
static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to)
{
/* Calculate how many bytes we need for the rest */
for (i = depth_to - 1; i >= 0; i--) {
+ const char *name;
for (kn = kn_to, j = 0; j < i; j++)
kn = rcu_dereference(kn->__parent);
- len += scnprintf(buf + len, buflen - len, "/%s", kn->name);
+ name = rcu_dereference(kn->name);
+ len += scnprintf(buf + len, buflen - len, "/%s", name);
}
return len;
*/
int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
{
- unsigned long flags;
- int ret;
+ struct kernfs_node *kn_parent;
- read_lock_irqsave(&kernfs_rename_lock, flags);
- ret = kernfs_name_locked(kn, buf, buflen);
- read_unlock_irqrestore(&kernfs_rename_lock, flags);
- return ret;
+ if (!kn)
+ return strscpy(buf, "(null)", buflen);
+
+ guard(rcu)();
+ /*
+ * KERNFS_ROOT_INVARIANT_PARENT is ignored here. The name is RCU freed and
+ * the parent is either existing or not.
+ */
+ kn_parent = rcu_dereference(kn->__parent);
+ return strscpy(buf, kn_parent ? rcu_dereference(kn->name) : "/", buflen);
}
/**
int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
char *buf, size_t buflen)
{
- unsigned long flags;
- int ret;
+ struct kernfs_root *root;
guard(rcu)();
- read_lock_irqsave(&kernfs_rename_lock, flags);
- ret = kernfs_path_from_node_locked(to, from, buf, buflen);
- read_unlock_irqrestore(&kernfs_rename_lock, flags);
- return ret;
+ if (to) {
+ root = kernfs_root(to);
+ if (!(root->flags & KERNFS_ROOT_INVARIANT_PARENT)) {
+ guard(read_lock_irqsave)(&kernfs_rename_lock);
+ return kernfs_path_from_node_locked(to, from, buf, buflen);
+ }
+ }
+ return kernfs_path_from_node_locked(to, from, buf, buflen);
}
EXPORT_SYMBOL_GPL(kernfs_path_from_node);
return -1;
if (ns > kn->ns)
return 1;
- return strcmp(name, kn->name);
+ return strcmp(name, kernfs_rcu_name(kn));
}
static int kernfs_sd_compare(const struct kernfs_node *left,
const struct kernfs_node *right)
{
- return kernfs_name_compare(left->hash, left->name, left->ns, right);
+ return kernfs_name_compare(left->hash, kernfs_rcu_name(left), left->ns, right);
}
/**
{
struct kernfs_node *kn = container_of(rcu, struct kernfs_node, rcu);
- kfree_const(kn->name);
+ /* If the whole node goes away, then name can't be used outside */
+ kfree_const(rcu_access_pointer(kn->name));
if (kn->iattr) {
simple_xattrs_free(&kn->iattr->xattrs, NULL);
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));
+ parent ? rcu_dereference(parent->name) : "",
+ rcu_dereference(kn->name), atomic_read(&kn->active));
if (kernfs_type(kn) == KERNFS_LINK)
kernfs_put(kn->symlink.target_kn);
atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
RB_CLEAR_NODE(&kn->rb);
- kn->name = name;
+ rcu_assign_pointer(kn->name, name);
kn->mode = mode;
kn->flags = flags;
ret = -EINVAL;
has_ns = kernfs_ns_enabled(parent);
if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
- has_ns ? "required" : "invalid", parent->name, kn->name))
+ has_ns ? "required" : "invalid",
+ kernfs_rcu_name(parent), kernfs_rcu_name(kn)))
goto out_unlock;
if (kernfs_type(parent) != KERNFS_DIR)
if (parent->flags & (KERNFS_REMOVING | KERNFS_EMPTY_DIR))
goto out_unlock;
- kn->hash = kernfs_name_hash(kn->name, kn->ns);
+ kn->hash = kernfs_name_hash(kernfs_rcu_name(kn), kn->ns);
ret = kernfs_link_sibling(kn);
if (ret)
if (has_ns != (bool)ns) {
WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
- has_ns ? "required" : "invalid", parent->name, name);
+ has_ns ? "required" : "invalid", kernfs_rcu_name(parent), name);
return NULL;
}
/* Negative hashed dentry? */
if (d_really_is_negative(dentry)) {
- struct kernfs_node *parent;
-
/* If the kernfs parent node has changed discard and
* proceed to ->lookup.
*
goto out_bad;
/* The kernfs node has been renamed */
- if (strcmp(dentry->d_name.name, kn->name) != 0)
+ if (strcmp(dentry->d_name.name, kernfs_rcu_name(kn)) != 0)
goto out_bad;
/* The kernfs node has been moved to a different namespace */
if (kernfs_parent(kn) && RB_EMPTY_NODE(&kn->rb))
return;
- pr_debug("kernfs %s: removing\n", kn->name);
+ pr_debug("kernfs %s: removing\n", kernfs_rcu_name(kn));
/* prevent new usage by marking all nodes removing and deactivating */
pos = NULL;
{
struct kernfs_node *old_parent;
struct kernfs_root *root;
- const char *old_name = NULL;
+ const char *old_name;
int error;
/* can't move or rename root */
}
error = 0;
+ old_name = kernfs_rcu_name(kn);
+ if (!new_name)
+ new_name = old_name;
if ((old_parent == new_parent) && (kn->ns == new_ns) &&
- (strcmp(kn->name, new_name) == 0))
+ (strcmp(old_name, new_name) == 0))
goto out; /* nothing to rename */
error = -EEXIST;
goto out;
/* rename kernfs_node */
- if (strcmp(kn->name, new_name) != 0) {
+ if (strcmp(old_name, new_name) != 0) {
error = -ENOMEM;
new_name = kstrdup_const(new_name, GFP_KERNEL);
if (!new_name)
* Move to the appropriate place in the appropriate directories rbtree.
*/
kernfs_unlink_sibling(kn);
- kernfs_get(new_parent);
- /* rename_lock protects ->parent and ->name accessors */
- write_lock_irq(&kernfs_rename_lock);
+ /* rename_lock protects ->parent accessors */
+ if (old_parent != new_parent) {
+ kernfs_get(new_parent);
+ write_lock_irq(&kernfs_rename_lock);
- old_parent = kernfs_parent(kn);
- rcu_assign_pointer(kn->__parent, new_parent);
+ rcu_assign_pointer(kn->__parent, new_parent);
- kn->ns = new_ns;
- if (new_name) {
- old_name = kn->name;
- kn->name = new_name;
- }
+ kn->ns = new_ns;
+ if (new_name)
+ rcu_assign_pointer(kn->name, new_name);
- write_unlock_irq(&kernfs_rename_lock);
+ write_unlock_irq(&kernfs_rename_lock);
+ kernfs_put(old_parent);
+ } else {
+ /* name assignment is RCU protected, parent is the same */
+ kn->ns = new_ns;
+ if (new_name)
+ rcu_assign_pointer(kn->name, new_name);
+ }
- kn->hash = kernfs_name_hash(kn->name, kn->ns);
+ kn->hash = kernfs_name_hash(new_name ?: old_name, kn->ns);
kernfs_link_sibling(kn);
- kernfs_put(old_parent);
- kfree_const(old_name);
+ if (new_name && !is_kernel_rodata((unsigned long)old_name))
+ kfree_rcu_mightsleep(old_name);
error = 0;
out:
for (pos = kernfs_dir_pos(ns, parent, ctx->pos, pos);
pos;
pos = kernfs_dir_next_pos(ns, parent, ctx->pos, pos)) {
- const char *name = pos->name;
+ const char *name = kernfs_rcu_name(pos);
unsigned int type = fs_umode_to_dtype(pos->mode);
int len = strlen(name);
ino_t ino = kernfs_ino(pos);
projects / thirdparty / linux.git / commitdiff
