예제 #1
0
/*! 2016-06-04 study -ing */
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;
	}

	/*! name + ns 로 31bit hash 생성하여 return */
	hash = kernfs_name_hash(name, ns);
	/*! hash 비교해 가면서 원하는 kn을 찾는다.  */
	while (node) {
		struct kernfs_node *kn;
		int result;

		kn = rb_to_kn(node);
		/*! hash 와 kn->hash 비교  */
		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;
}
예제 #2
0
파일: dir.c 프로젝트: AK101111/linux
/**
 *	kernfs_add_one - add kernfs_node to parent without warning
 *	@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.
 *
 *	RETURNS:
 *	0 on success, -EEXIST if entry with the given name already
 *	exists.
 */
int kernfs_add_one(struct kernfs_node *kn)
{
	struct kernfs_node *parent = kn->parent;
	struct kernfs_iattrs *ps_iattr;
	bool has_ns;
	int ret;

	mutex_lock(&kernfs_mutex);

	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))
		goto out_unlock;

	if (kernfs_type(parent) != KERNFS_DIR)
		goto out_unlock;

	ret = -ENOENT;
	if (parent->flags & KERNFS_EMPTY_DIR)
		goto out_unlock;

	if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent))
		goto out_unlock;

	kn->hash = kernfs_name_hash(kn->name, kn->ns);

	ret = kernfs_link_sibling(kn);
	if (ret)
		goto out_unlock;

	/* Update timestamps on the parent */
	ps_iattr = parent->iattr;
	if (ps_iattr) {
		struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
		ktime_get_real_ts(&ps_iattrs->ia_ctime);
		ps_iattrs->ia_mtime = ps_iattrs->ia_ctime;
	}

	mutex_unlock(&kernfs_mutex);

	/*
	 * Activate the new node unless CREATE_DEACTIVATED is requested.
	 * If not activated here, the kernfs user is responsible for
	 * activating the node with kernfs_activate().  A node which hasn't
	 * been activated is not visible to userland and its removal won't
	 * trigger deactivation.
	 */
	if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
		kernfs_activate(kn);
	return 0;

out_unlock:
	mutex_unlock(&kernfs_mutex);
	return ret;
}
예제 #3
0
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;
}
예제 #4
0
/**
 *	sysfs_delete_link - remove symlink in object's directory.
 *	@kobj:	object we're acting for.
 *	@targ:	object we're pointing to.
 *	@name:	name of the symlink to remove.
 *
 *	Unlike sysfs_remove_link sysfs_delete_link has enough information
 *	to successfully delete symlinks in tagged directories.
 */
void sysfs_delete_link(struct kobject *kobj, struct kobject *targ,
                       const char *name)
{
    const void *ns = NULL;

    /*
     * We don't own @target and it may be removed at any time.
     * Synchronize using sysfs_symlink_target_lock.  See
     * sysfs_remove_dir() for details.
     */
    spin_lock(&sysfs_symlink_target_lock);
    if (targ->sd && kernfs_ns_enabled(kobj->sd))
        ns = targ->sd->ns;
    spin_unlock(&sysfs_symlink_target_lock);
    kernfs_remove_by_name_ns(kobj->sd, name, ns);
}
예제 #5
0
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;
}
예제 #6
0
파일: dir.c 프로젝트: andy-shev/linux
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 (d_really_is_negative(dentry))
		goto out_bad_unlocked;

	kn = dentry->d_fsdata;
	mutex_lock(&kernfs_mutex);

	/* The kernfs node has been deactivated */
	if (!kernfs_active(kn))
		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);
	return 1;
out_bad:
	mutex_unlock(&kernfs_mutex);
out_bad_unlocked:
	return 0;
}
예제 #7
0
파일: symlink.c 프로젝트: 020gzh/linux
/**
 * kernfs_create_link - create a symlink
 * @parent: directory to create the symlink in
 * @name: name of the symlink
 * @target: target node for the symlink to point to
 *
 * Returns the created node on success, ERR_PTR() value on error.
 */
struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
				       const char *name,
				       struct kernfs_node *target)
{
	struct kernfs_node *kn;
	int error;

	kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
	if (!kn)
		return ERR_PTR(-ENOMEM);

	if (kernfs_ns_enabled(parent))
		kn->ns = target->ns;
	kn->symlink.target_kn = target;
	kernfs_get(target);	/* ref owned by symlink */

	error = kernfs_add_one(kn);
	if (!error)
		return kn;

	kernfs_put(kn);
	return ERR_PTR(error);
}
예제 #8
0
/*! 2017. 8.12 study -ing */
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;
}
예제 #9
0
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;
}