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-rw-r--r--fs/kernfs/dir.c1073
1 files changed, 1073 insertions, 0 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
new file mode 100644
index 000000000000..5104cf5d25c5
--- /dev/null
+++ b/fs/kernfs/dir.c
@@ -0,0 +1,1073 @@
+/*
+ * fs/kernfs/dir.c - kernfs directory implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/idr.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include <linux/hash.h>
+
+#include "kernfs-internal.h"
+
+DEFINE_MUTEX(kernfs_mutex);
+
+#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
+
+/**
+ * kernfs_name_hash
+ * @name: Null terminated string to hash
+ * @ns: Namespace tag to hash
+ *
+ * Returns 31 bit hash of ns + name (so it fits in an off_t )
+ */
+static unsigned int kernfs_name_hash(const char *name, const void *ns)
+{
+ unsigned long hash = init_name_hash();
+ unsigned int len = strlen(name);
+ while (len--)
+ hash = partial_name_hash(*name++, hash);
+ hash = (end_name_hash(hash) ^ hash_ptr((void *)ns, 31));
+ hash &= 0x7fffffffU;
+ /* Reserve hash numbers 0, 1 and INT_MAX for magic directory entries */
+ if (hash < 1)
+ hash += 2;
+ if (hash >= INT_MAX)
+ hash = INT_MAX - 1;
+ return hash;
+}
+
+static int kernfs_name_compare(unsigned int hash, const char *name,
+ const void *ns, const struct kernfs_node *kn)
+{
+ if (hash != kn->hash)
+ return hash - kn->hash;
+ if (ns != kn->ns)
+ return ns - kn->ns;
+ return strcmp(name, kn->name);
+}
+
+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);
+}
+
+/**
+ * kernfs_link_sibling - link kernfs_node into sibling rbtree
+ * @kn: kernfs_node of interest
+ *
+ * Link @kn into its sibling rbtree which starts from
+ * @kn->parent->dir.children.
+ *
+ * Locking:
+ * mutex_lock(kernfs_mutex)
+ *
+ * RETURNS:
+ * 0 on susccess -EEXIST on failure.
+ */
+static int kernfs_link_sibling(struct kernfs_node *kn)
+{
+ struct rb_node **node = &kn->parent->dir.children.rb_node;
+ struct rb_node *parent = NULL;
+
+ if (kernfs_type(kn) == KERNFS_DIR)
+ kn->parent->dir.subdirs++;
+
+ while (*node) {
+ struct kernfs_node *pos;
+ int result;
+
+ pos = rb_to_kn(*node);
+ parent = *node;
+ result = kernfs_sd_compare(kn, pos);
+ if (result < 0)
+ node = &pos->rb.rb_left;
+ else if (result > 0)
+ node = &pos->rb.rb_right;
+ else
+ return -EEXIST;
+ }
+ /* add new node and rebalance the tree */
+ rb_link_node(&kn->rb, parent, node);
+ rb_insert_color(&kn->rb, &kn->parent->dir.children);
+ return 0;
+}
+
+/**
+ * kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
+ * @kn: kernfs_node of interest
+ *
+ * Unlink @kn from its sibling rbtree which starts from
+ * kn->parent->dir.children.
+ *
+ * Locking:
+ * mutex_lock(kernfs_mutex)
+ */
+static void kernfs_unlink_sibling(struct kernfs_node *kn)
+{
+ if (kernfs_type(kn) == KERNFS_DIR)
+ kn->parent->dir.subdirs--;
+
+ rb_erase(&kn->rb, &kn->parent->dir.children);
+}
+
+/**
+ * kernfs_get_active - get an active reference to kernfs_node
+ * @kn: kernfs_node to get an active reference to
+ *
+ * Get an active reference of @kn. This function is noop if @kn
+ * is NULL.
+ *
+ * RETURNS:
+ * Pointer to @kn on success, NULL on failure.
+ */
+struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
+{
+ if (unlikely(!kn))
+ return NULL;
+
+ if (!atomic_inc_unless_negative(&kn->active))
+ return NULL;
+
+ if (kn->flags & KERNFS_LOCKDEP)
+ rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
+ return kn;
+}
+
+/**
+ * kernfs_put_active - put an active reference to kernfs_node
+ * @kn: kernfs_node to put an active reference to
+ *
+ * Put an active reference to @kn. This function is noop if @kn
+ * is NULL.
+ */
+void kernfs_put_active(struct kernfs_node *kn)
+{
+ int v;
+
+ if (unlikely(!kn))
+ return;
+
+ if (kn->flags & KERNFS_LOCKDEP)
+ rwsem_release(&kn->dep_map, 1, _RET_IP_);
+ v = atomic_dec_return(&kn->active);
+ if (likely(v != KN_DEACTIVATED_BIAS))
+ return;
+
+ /*
+ * atomic_dec_return() is a mb(), we'll always see the updated
+ * kn->u.completion.
+ */
+ complete(kn->u.completion);
+}
+
+/**
+ * kernfs_deactivate - deactivate kernfs_node
+ * @kn: kernfs_node to deactivate
+ *
+ * Deny new active references and drain existing ones.
+ */
+static void kernfs_deactivate(struct kernfs_node *kn)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ int v;
+
+ BUG_ON(!(kn->flags & KERNFS_REMOVED));
+
+ if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF))
+ return;
+
+ kn->u.completion = (void *)&wait;
+
+ rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
+ /* atomic_add_return() is a mb(), put_active() will always see
+ * the updated kn->u.completion.
+ */
+ v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active);
+
+ if (v != KN_DEACTIVATED_BIAS) {
+ lock_contended(&kn->dep_map, _RET_IP_);
+ wait_for_completion(&wait);
+ }
+
+ lock_acquired(&kn->dep_map, _RET_IP_);
+ rwsem_release(&kn->dep_map, 1, _RET_IP_);
+}
+
+/**
+ * kernfs_get - get a reference count on a kernfs_node
+ * @kn: the target kernfs_node
+ */
+void kernfs_get(struct kernfs_node *kn)
+{
+ if (kn) {
+ WARN_ON(!atomic_read(&kn->count));
+ atomic_inc(&kn->count);
+ }
+}
+EXPORT_SYMBOL_GPL(kernfs_get);
+
+/**
+ * kernfs_put - put a reference count on a kernfs_node
+ * @kn: the target kernfs_node
+ *
+ * Put a reference count of @kn and destroy it if it reached zero.
+ */
+void kernfs_put(struct kernfs_node *kn)
+{
+ struct kernfs_node *parent;
+ struct kernfs_root *root;
+
+ if (!kn || !atomic_dec_and_test(&kn->count))
+ return;
+ root = kernfs_root(kn);
+ repeat:
+ /* 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);
+
+ if (kernfs_type(kn) == KERNFS_LINK)
+ kernfs_put(kn->symlink.target_kn);
+ if (!(kn->flags & KERNFS_STATIC_NAME))
+ kfree(kn->name);
+ if (kn->iattr) {
+ if (kn->iattr->ia_secdata)
+ security_release_secctx(kn->iattr->ia_secdata,
+ kn->iattr->ia_secdata_len);
+ simple_xattrs_free(&kn->iattr->xattrs);
+ }
+ kfree(kn->iattr);
+ ida_simple_remove(&root->ino_ida, kn->ino);
+ kmem_cache_free(kernfs_node_cache, kn);
+
+ kn = parent;
+ if (kn) {
+ if (atomic_dec_and_test(&kn->count))
+ goto repeat;
+ } else {
+ /* just released the root kn, free @root too */
+ ida_destroy(&root->ino_ida);
+ kfree(root);
+ }
+}
+EXPORT_SYMBOL_GPL(kernfs_put);
+
+static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct kernfs_node *kn;
+
+ if (flags & LOOKUP_RCU)
+ return -ECHILD;
+
+ /* Always perform fresh lookup for negatives */
+ if (!dentry->d_inode)
+ goto out_bad_unlocked;
+
+ kn = dentry->d_fsdata;
+ mutex_lock(&kernfs_mutex);
+
+ /* The kernfs node has been deleted */
+ if (kn->flags & KERNFS_REMOVED)
+ goto out_bad;
+
+ /* The kernfs node has been moved? */
+ if (dentry->d_parent->d_fsdata != kn->parent)
+ goto out_bad;
+
+ /* The kernfs node has been renamed */
+ if (strcmp(dentry->d_name.name, kn->name) != 0)
+ goto out_bad;
+
+ /* The kernfs node has been moved to a different namespace */
+ if (kn->parent && kernfs_ns_enabled(kn->parent) &&
+ kernfs_info(dentry->d_sb)->ns != kn->ns)
+ goto out_bad;
+
+ mutex_unlock(&kernfs_mutex);
+out_valid:
+ return 1;
+out_bad:
+ mutex_unlock(&kernfs_mutex);
+out_bad_unlocked:
+ /*
+ * @dentry doesn't match the underlying kernfs node, drop the
+ * dentry and force lookup. If we have submounts we must allow the
+ * vfs caches to lie about the state of the filesystem to prevent
+ * leaks and other nasty things, so use check_submounts_and_drop()
+ * instead of d_drop().
+ */
+ if (check_submounts_and_drop(dentry) != 0)
+ goto out_valid;
+
+ return 0;
+}
+
+static void kernfs_dop_release(struct dentry *dentry)
+{
+ kernfs_put(dentry->d_fsdata);
+}
+
+const struct dentry_operations kernfs_dops = {
+ .d_revalidate = kernfs_dop_revalidate,
+ .d_release = kernfs_dop_release,
+};
+
+static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
+ const char *name, umode_t mode,
+ unsigned flags)
+{
+ char *dup_name = NULL;
+ struct kernfs_node *kn;
+ int ret;
+
+ if (!(flags & KERNFS_STATIC_NAME)) {
+ name = dup_name = kstrdup(name, GFP_KERNEL);
+ if (!name)
+ return NULL;
+ }
+
+ kn = kmem_cache_zalloc(kernfs_node_cache, GFP_KERNEL);
+ if (!kn)
+ goto err_out1;
+
+ ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
+ if (ret < 0)
+ goto err_out2;
+ kn->ino = ret;
+
+ atomic_set(&kn->count, 1);
+ atomic_set(&kn->active, 0);
+
+ kn->name = name;
+ kn->mode = mode;
+ kn->flags = flags | KERNFS_REMOVED;
+
+ return kn;
+
+ err_out2:
+ kmem_cache_free(kernfs_node_cache, kn);
+ err_out1:
+ kfree(dup_name);
+ return NULL;
+}
+
+struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
+ const char *name, umode_t mode,
+ unsigned flags)
+{
+ struct kernfs_node *kn;
+
+ kn = __kernfs_new_node(kernfs_root(parent), name, mode, flags);
+ if (kn) {
+ kernfs_get(parent);
+ kn->parent = parent;
+ }
+ return kn;
+}
+
+/**
+ * kernfs_addrm_start - prepare for kernfs_node add/remove
+ * @acxt: pointer to kernfs_addrm_cxt to be used
+ *
+ * This function is called when the caller is about to add or remove
+ * kernfs_node. This function acquires kernfs_mutex. @acxt is used
+ * to keep and pass context to other addrm functions.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep). kernfs_mutex is locked on
+ * return.
+ */
+void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
+ __acquires(kernfs_mutex)
+{
+ memset(acxt, 0, sizeof(*acxt));
+
+ mutex_lock(&kernfs_mutex);
+}
+
+/**
+ * kernfs_add_one - add kernfs_node to parent without warning
+ * @acxt: addrm context to use
+ * @kn: kernfs_node to be added
+ *
+ * The caller must already have initialized @kn->parent. This
+ * function increments nlink of the parent's inode if @kn is a
+ * directory and link into the children list of the parent.
+ *
+ * This function should be called between calls to
+ * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
+ * the same @acxt as passed to kernfs_addrm_start().
+ *
+ * LOCKING:
+ * Determined by kernfs_addrm_start().
+ *
+ * RETURNS:
+ * 0 on success, -EEXIST if entry with the given name already
+ * exists.
+ */
+int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
+{
+ struct kernfs_node *parent = kn->parent;
+ bool has_ns = kernfs_ns_enabled(parent);
+ struct kernfs_iattrs *ps_iattr;
+ int ret;
+
+ 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);
+ return -EINVAL;
+ }
+
+ if (kernfs_type(parent) != KERNFS_DIR)
+ return -EINVAL;
+
+ if (parent->flags & KERNFS_REMOVED)
+ return -ENOENT;
+
+ kn->hash = kernfs_name_hash(kn->name, kn->ns);
+
+ ret = kernfs_link_sibling(kn);
+ if (ret)
+ return ret;
+
+ /* Update timestamps on the parent */
+ ps_iattr = parent->iattr;
+ if (ps_iattr) {
+ struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
+ ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
+ }
+
+ /* Mark the entry added into directory tree */
+ kn->flags &= ~KERNFS_REMOVED;
+
+ return 0;
+}
+
+/**
+ * kernfs_remove_one - remove kernfs_node from parent
+ * @acxt: addrm context to use
+ * @kn: kernfs_node to be removed
+ *
+ * Mark @kn removed and drop nlink of parent inode if @kn is a
+ * directory. @kn is unlinked from the children list.
+ *
+ * This function should be called between calls to
+ * kernfs_addrm_start() and kernfs_addrm_finish() and should be
+ * passed the same @acxt as passed to kernfs_addrm_start().
+ *
+ * LOCKING:
+ * Determined by kernfs_addrm_start().
+ */
+static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
+ struct kernfs_node *kn)
+{
+ struct kernfs_iattrs *ps_iattr;
+
+ /*
+ * 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)
+ return;
+
+ if (kn->parent) {
+ kernfs_unlink_sibling(kn);
+
+ /* Update timestamps on the parent */
+ ps_iattr = kn->parent->iattr;
+ if (ps_iattr) {
+ ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
+ ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
+ }
+ }
+
+ kn->flags |= KERNFS_REMOVED;
+ kn->u.removed_list = acxt->removed;
+ acxt->removed = kn;
+}
+
+/**
+ * kernfs_addrm_finish - finish up kernfs_node add/remove
+ * @acxt: addrm context to finish up
+ *
+ * Finish up kernfs_node add/remove. Resources acquired by
+ * kernfs_addrm_start() are released and removed kernfs_nodes are
+ * cleaned up.
+ *
+ * LOCKING:
+ * kernfs_mutex is released.
+ */
+void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
+ __releases(kernfs_mutex)
+{
+ /* release resources acquired by kernfs_addrm_start() */
+ mutex_unlock(&kernfs_mutex);
+
+ /* kill removed kernfs_nodes */
+ while (acxt->removed) {
+ struct kernfs_node *kn = acxt->removed;
+
+ acxt->removed = kn->u.removed_list;
+
+ kernfs_deactivate(kn);
+ kernfs_unmap_bin_file(kn);
+ kernfs_put(kn);
+ }
+}
+
+/**
+ * kernfs_find_ns - find kernfs_node with the given name
+ * @parent: kernfs_node to search under
+ * @name: name to look for
+ * @ns: the namespace tag to use
+ *
+ * Look for kernfs_node with name @name under @parent. Returns pointer to
+ * the found kernfs_node on success, %NULL on failure.
+ */
+static struct kernfs_node *kernfs_find_ns(struct kernfs_node *parent,
+ const unsigned char *name,
+ const void *ns)
+{
+ struct rb_node *node = parent->dir.children.rb_node;
+ bool has_ns = kernfs_ns_enabled(parent);
+ unsigned int hash;
+
+ lockdep_assert_held(&kernfs_mutex);
+
+ if (has_ns != (bool)ns) {
+ WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
+ has_ns ? "required" : "invalid", parent->name, name);
+ return NULL;
+ }
+
+ hash = kernfs_name_hash(name, ns);
+ while (node) {
+ struct kernfs_node *kn;
+ int result;
+
+ kn = rb_to_kn(node);
+ result = kernfs_name_compare(hash, name, ns, kn);
+ if (result < 0)
+ node = node->rb_left;
+ else if (result > 0)
+ node = node->rb_right;
+ else
+ return kn;
+ }
+ return NULL;
+}
+
+/**
+ * kernfs_find_and_get_ns - find and get kernfs_node with the given name
+ * @parent: kernfs_node to search under
+ * @name: name to look for
+ * @ns: the namespace tag to use
+ *
+ * Look for kernfs_node with name @name under @parent and get a reference
+ * if found. This function may sleep and returns pointer to the found
+ * kernfs_node on success, %NULL on failure.
+ */
+struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
+ const char *name, const void *ns)
+{
+ struct kernfs_node *kn;
+
+ mutex_lock(&kernfs_mutex);
+ kn = kernfs_find_ns(parent, name, ns);
+ kernfs_get(kn);
+ mutex_unlock(&kernfs_mutex);
+
+ return kn;
+}
+EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
+
+/**
+ * kernfs_create_root - create a new kernfs hierarchy
+ * @kdops: optional directory syscall operations for the hierarchy
+ * @priv: opaque data associated with the new directory
+ *
+ * Returns the root of the new hierarchy on success, ERR_PTR() value on
+ * failure.
+ */
+struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
+{
+ struct kernfs_root *root;
+ struct kernfs_node *kn;
+
+ root = kzalloc(sizeof(*root), GFP_KERNEL);
+ if (!root)
+ return ERR_PTR(-ENOMEM);
+
+ ida_init(&root->ino_ida);
+
+ kn = __kernfs_new_node(root, "", S_IFDIR | S_IRUGO | S_IXUGO,
+ KERNFS_DIR);
+ if (!kn) {
+ ida_destroy(&root->ino_ida);
+ kfree(root);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ kn->flags &= ~KERNFS_REMOVED;
+ kn->priv = priv;
+ kn->dir.root = root;
+
+ root->dir_ops = kdops;
+ root->kn = kn;
+
+ return root;
+}
+
+/**
+ * kernfs_destroy_root - destroy a kernfs hierarchy
+ * @root: root of the hierarchy to destroy
+ *
+ * Destroy the hierarchy anchored at @root by removing all existing
+ * directories and destroying @root.
+ */
+void kernfs_destroy_root(struct kernfs_root *root)
+{
+ kernfs_remove(root->kn); /* will also free @root */
+}
+
+/**
+ * kernfs_create_dir_ns - create a directory
+ * @parent: parent in which to create a new directory
+ * @name: name of the new directory
+ * @mode: mode of the new directory
+ * @priv: opaque data associated with the new directory
+ * @ns: optional namespace tag of the directory
+ *
+ * Returns the created node on success, ERR_PTR() value on failure.
+ */
+struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
+ const char *name, umode_t mode,
+ void *priv, const void *ns)
+{
+ struct kernfs_addrm_cxt acxt;
+ struct kernfs_node *kn;
+ int rc;
+
+ /* allocate */
+ kn = kernfs_new_node(parent, name, mode | S_IFDIR, KERNFS_DIR);
+ if (!kn)
+ return ERR_PTR(-ENOMEM);
+
+ kn->dir.root = parent->dir.root;
+ kn->ns = ns;
+ kn->priv = priv;
+
+ /* link in */
+ kernfs_addrm_start(&acxt);
+ rc = kernfs_add_one(&acxt, kn);
+ kernfs_addrm_finish(&acxt);
+
+ if (!rc)
+ return kn;
+
+ kernfs_put(kn);
+ return ERR_PTR(rc);
+}
+
+static struct dentry *kernfs_iop_lookup(struct inode *dir,
+ struct dentry *dentry,
+ unsigned int flags)
+{
+ struct dentry *ret;
+ struct kernfs_node *parent = dentry->d_parent->d_fsdata;
+ struct kernfs_node *kn;
+ struct inode *inode;
+ const void *ns = NULL;
+
+ mutex_lock(&kernfs_mutex);
+
+ if (kernfs_ns_enabled(parent))
+ ns = kernfs_info(dir->i_sb)->ns;
+
+ kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
+
+ /* no such entry */
+ if (!kn) {
+ ret = NULL;
+ goto out_unlock;
+ }
+ kernfs_get(kn);
+ dentry->d_fsdata = kn;
+
+ /* attach dentry and inode */
+ inode = kernfs_get_inode(dir->i_sb, kn);
+ if (!inode) {
+ ret = ERR_PTR(-ENOMEM);
+ goto out_unlock;
+ }
+
+ /* instantiate and hash dentry */
+ ret = d_materialise_unique(dentry, inode);
+ out_unlock:
+ mutex_unlock(&kernfs_mutex);
+ return ret;
+}
+
+static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
+ umode_t mode)
+{
+ struct kernfs_node *parent = dir->i_private;
+ struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
+
+ if (!kdops || !kdops->mkdir)
+ return -EPERM;
+
+ return kdops->mkdir(parent, dentry->d_name.name, mode);
+}
+
+static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct kernfs_node *kn = dentry->d_fsdata;
+ struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
+
+ if (!kdops || !kdops->rmdir)
+ return -EPERM;
+
+ return kdops->rmdir(kn);
+}
+
+static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
+ struct inode *new_dir, struct dentry *new_dentry)
+{
+ struct kernfs_node *kn = old_dentry->d_fsdata;
+ struct kernfs_node *new_parent = new_dir->i_private;
+ struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
+
+ if (!kdops || !kdops->rename)
+ return -EPERM;
+
+ return kdops->rename(kn, new_parent, new_dentry->d_name.name);
+}
+
+const struct inode_operations kernfs_dir_iops = {
+ .lookup = kernfs_iop_lookup,
+ .permission = kernfs_iop_permission,
+ .setattr = kernfs_iop_setattr,
+ .getattr = kernfs_iop_getattr,
+ .setxattr = kernfs_iop_setxattr,
+ .removexattr = kernfs_iop_removexattr,
+ .getxattr = kernfs_iop_getxattr,
+ .listxattr = kernfs_iop_listxattr,
+
+ .mkdir = kernfs_iop_mkdir,
+ .rmdir = kernfs_iop_rmdir,
+ .rename = kernfs_iop_rename,
+};
+
+static struct kernfs_node *kernfs_leftmost_descendant(struct kernfs_node *pos)
+{
+ struct kernfs_node *last;
+
+ while (true) {
+ struct rb_node *rbn;
+
+ last = pos;
+
+ if (kernfs_type(pos) != KERNFS_DIR)
+ break;
+
+ rbn = rb_first(&pos->dir.children);
+ if (!rbn)
+ break;
+
+ pos = rb_to_kn(rbn);
+ }
+
+ return last;
+}
+
+/**
+ * kernfs_next_descendant_post - find the next descendant for post-order walk
+ * @pos: the current position (%NULL to initiate traversal)
+ * @root: kernfs_node whose descendants to walk
+ *
+ * Find the next descendant to visit for post-order traversal of @root's
+ * descendants. @root is included in the iteration and the last node to be
+ * visited.
+ */
+static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
+ struct kernfs_node *root)
+{
+ struct rb_node *rbn;
+
+ lockdep_assert_held(&kernfs_mutex);
+
+ /* if first iteration, visit leftmost descendant which may be root */
+ if (!pos)
+ return kernfs_leftmost_descendant(root);
+
+ /* if we visited @root, we're done */
+ if (pos == root)
+ return NULL;
+
+ /* if there's an unvisited sibling, visit its leftmost descendant */
+ rbn = rb_next(&pos->rb);
+ if (rbn)
+ return kernfs_leftmost_descendant(rb_to_kn(rbn));
+
+ /* no sibling left, visit parent */
+ return pos->parent;
+}
+
+static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
+ struct kernfs_node *kn)
+{
+ struct kernfs_node *pos, *next;
+
+ if (!kn)
+ return;
+
+ pr_debug("kernfs %s: removing\n", kn->name);
+
+ next = NULL;
+ do {
+ pos = next;
+ next = kernfs_next_descendant_post(pos, kn);
+ if (pos)
+ kernfs_remove_one(acxt, pos);
+ } while (next);
+}
+
+/**
+ * kernfs_remove - remove a kernfs_node recursively
+ * @kn: the kernfs_node to remove
+ *
+ * Remove @kn along with all its subdirectories and files.
+ */
+void kernfs_remove(struct kernfs_node *kn)
+{
+ struct kernfs_addrm_cxt acxt;
+
+ kernfs_addrm_start(&acxt);
+ __kernfs_remove(&acxt, kn);
+ kernfs_addrm_finish(&acxt);
+}
+
+/**
+ * kernfs_remove_by_name_ns - find a kernfs_node by name and remove it
+ * @parent: parent of the target
+ * @name: name of the kernfs_node to remove
+ * @ns: namespace tag of the kernfs_node to remove
+ *
+ * Look for the kernfs_node with @name and @ns under @parent and remove it.
+ * Returns 0 on success, -ENOENT if such entry doesn't exist.
+ */
+int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
+ const void *ns)
+{
+ struct kernfs_addrm_cxt acxt;
+ struct kernfs_node *kn;
+
+ if (!parent) {
+ WARN(1, KERN_WARNING "kernfs: can not remove '%s', no directory\n",
+ name);
+ return -ENOENT;
+ }
+
+ kernfs_addrm_start(&acxt);
+
+ kn = kernfs_find_ns(parent, name, ns);
+ if (kn)
+ __kernfs_remove(&acxt, kn);
+
+ kernfs_addrm_finish(&acxt);
+
+ if (kn)
+ return 0;
+ else
+ return -ENOENT;
+}
+
+/**
+ * kernfs_rename_ns - move and rename a kernfs_node
+ * @kn: target node
+ * @new_parent: new parent to put @sd under
+ * @new_name: new name
+ * @new_ns: new namespace tag
+ */
+int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
+ const char *new_name, const void *new_ns)
+{
+ int error;
+
+ mutex_lock(&kernfs_mutex);
+
+ error = -ENOENT;
+ if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
+ goto out;
+
+ error = 0;
+ if ((kn->parent == new_parent) && (kn->ns == new_ns) &&
+ (strcmp(kn->name, new_name) == 0))
+ goto out; /* nothing to rename */
+
+ error = -EEXIST;
+ if (kernfs_find_ns(new_parent, new_name, new_ns))
+ goto out;
+
+ /* rename kernfs_node */
+ if (strcmp(kn->name, new_name) != 0) {
+ error = -ENOMEM;
+ new_name = kstrdup(new_name, GFP_KERNEL);
+ if (!new_name)
+ goto out;
+
+ if (kn->flags & KERNFS_STATIC_NAME)
+ kn->flags &= ~KERNFS_STATIC_NAME;
+ else
+ kfree(kn->name);
+
+ kn->name = new_name;
+ }
+
+ /*
+ * Move to the appropriate place in the appropriate directories rbtree.
+ */
+ kernfs_unlink_sibling(kn);
+ kernfs_get(new_parent);
+ kernfs_put(kn->parent);
+ kn->ns = new_ns;
+ kn->hash = kernfs_name_hash(kn->name, kn->ns);
+ kn->parent = new_parent;
+ kernfs_link_sibling(kn);
+
+ error = 0;
+ out:
+ mutex_unlock(&kernfs_mutex);
+ return error;
+}
+
+/* Relationship between s_mode and the DT_xxx types */
+static inline unsigned char dt_type(struct kernfs_node *kn)
+{
+ return (kn->mode >> 12) & 15;
+}
+
+static int kernfs_dir_fop_release(struct inode *inode, struct file *filp)
+{
+ kernfs_put(filp->private_data);
+ return 0;
+}
+
+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;
+ kernfs_put(pos);
+ if (!valid)
+ pos = NULL;
+ }
+ if (!pos && (hash > 1) && (hash < INT_MAX)) {
+ struct rb_node *node = parent->dir.children.rb_node;
+ while (node) {
+ pos = rb_to_kn(node);
+
+ if (hash < pos->hash)
+ node = node->rb_left;
+ else if (hash > pos->hash)
+ node = node->rb_right;
+ else
+ break;
+ }
+ }
+ /* Skip over entries in the wrong namespace */
+ while (pos && pos->ns != ns) {
+ struct rb_node *node = rb_next(&pos->rb);
+ if (!node)
+ pos = NULL;
+ else
+ pos = rb_to_kn(node);
+ }
+ return pos;
+}
+
+static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
+ struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
+{
+ pos = kernfs_dir_pos(ns, parent, ino, pos);
+ if (pos)
+ do {
+ struct rb_node *node = rb_next(&pos->rb);
+ if (!node)
+ pos = NULL;
+ else
+ pos = rb_to_kn(node);
+ } while (pos && pos->ns != ns);
+ return pos;
+}
+
+static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
+{
+ struct dentry *dentry = file->f_path.dentry;
+ struct kernfs_node *parent = dentry->d_fsdata;
+ struct kernfs_node *pos = file->private_data;
+ const void *ns = NULL;
+
+ if (!dir_emit_dots(file, ctx))
+ return 0;
+ mutex_lock(&kernfs_mutex);
+
+ if (kernfs_ns_enabled(parent))
+ ns = kernfs_info(dentry->d_sb)->ns;
+
+ 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;
+ unsigned int type = dt_type(pos);
+ int len = strlen(name);
+ ino_t ino = pos->ino;
+
+ ctx->pos = pos->hash;
+ file->private_data = pos;
+ kernfs_get(pos);
+
+ mutex_unlock(&kernfs_mutex);
+ if (!dir_emit(ctx, name, len, ino, type))
+ return 0;
+ mutex_lock(&kernfs_mutex);
+ }
+ mutex_unlock(&kernfs_mutex);
+ file->private_data = NULL;
+ ctx->pos = INT_MAX;
+ return 0;
+}
+
+static loff_t kernfs_dir_fop_llseek(struct file *file, loff_t offset,
+ int whence)
+{
+ struct inode *inode = file_inode(file);
+ loff_t ret;
+
+ mutex_lock(&inode->i_mutex);
+ ret = generic_file_llseek(file, offset, whence);
+ mutex_unlock(&inode->i_mutex);
+
+ return ret;
+}
+
+const struct file_operations kernfs_dir_fops = {
+ .read = generic_read_dir,
+ .iterate = kernfs_fop_readdir,
+ .release = kernfs_dir_fop_release,
+ .llseek = kernfs_dir_fop_llseek,
+};