zfs_onexit.c

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/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/kmem.h>
#include <sys/conf.h>
#include <sys/sunddi.h>
#include <sys/zfs_ioctl.h>
#include <sys/zfs_onexit.h>
#include <sys/zvol.h>

void
zfs_onexit_init(zfs_onexit_t **zop)
{
        zfs_onexit_t *zo;

        zo = *zop = kmem_zalloc(sizeof (zfs_onexit_t), KM_SLEEP);
        mutex_init(&zo->zo_lock, NULL, MUTEX_DEFAULT, NULL);
        list_create(&zo->zo_actions, sizeof (zfs_onexit_action_node_t),
            offsetof(zfs_onexit_action_node_t, za_link));
}

void
zfs_onexit_destroy(zfs_onexit_t *zo)
{
        zfs_onexit_action_node_t *ap;

        mutex_enter(&zo->zo_lock);
        while ((ap = list_head(&zo->zo_actions)) != NULL) {
                list_remove(&zo->zo_actions, ap);
                mutex_exit(&zo->zo_lock);
                ap->za_func(ap->za_data);
                kmem_free(ap, sizeof (zfs_onexit_action_node_t));
                mutex_enter(&zo->zo_lock);
        }
        mutex_exit(&zo->zo_lock);

        list_destroy(&zo->zo_actions);
        mutex_destroy(&zo->zo_lock);
        kmem_free(zo, sizeof (zfs_onexit_t));
}

static int
zfs_onexit_minor_to_state(minor_t minor, zfs_onexit_t **zo)
{
        *zo = zfsdev_get_soft_state(minor, ZSST_CTLDEV);
        if (*zo == NULL)
                return (EBADF);

        return (0);
}

int
zfs_onexit_fd_hold(int fd, minor_t *minorp)
{
        file_t *fp, *tmpfp;
        zfs_onexit_t *zo;
        void *data;
        int error;

        fp = getf(fd);
        if (fp == NULL)
                return (EBADF);

        tmpfp = curthread->td_fpop;
        curthread->td_fpop = fp;
        error = devfs_get_cdevpriv(&data);
        if (error == 0)
                *minorp = (minor_t)(uintptr_t)data;
        curthread->td_fpop = tmpfp;
        if (error != 0)
                return (error);
        return (zfs_onexit_minor_to_state(*minorp, &zo));
}

void
zfs_onexit_fd_rele(int fd)
{
        releasef(fd);
}

int
zfs_onexit_add_cb(minor_t minor, void (*func)(void *), void *data,
    uint64_t *action_handle)
{
        zfs_onexit_t *zo;
        zfs_onexit_action_node_t *ap;
        int error;

        error = zfs_onexit_minor_to_state(minor, &zo);
        if (error)
                return (error);

        ap = kmem_alloc(sizeof (zfs_onexit_action_node_t), KM_SLEEP);
        list_link_init(&ap->za_link);
        ap->za_func = func;
        ap->za_data = data;

        mutex_enter(&zo->zo_lock);
        list_insert_tail(&zo->zo_actions, ap);
        mutex_exit(&zo->zo_lock);
        if (action_handle)
                *action_handle = (uint64_t)(uintptr_t)ap;

        return (0);
}

static zfs_onexit_action_node_t *
zfs_onexit_find_cb(zfs_onexit_t *zo, uint64_t action_handle)
{
        zfs_onexit_action_node_t *match;
        zfs_onexit_action_node_t *ap;
        list_t *l;

        ASSERT(MUTEX_HELD(&zo->zo_lock));

        match = (zfs_onexit_action_node_t *)(uintptr_t)action_handle;
        l = &zo->zo_actions;
        for (ap = list_head(l); ap != NULL; ap = list_next(l, ap)) {
                if (match == ap)
                        break;
        }
        return (ap);
}

int
zfs_onexit_del_cb(minor_t minor, uint64_t action_handle, boolean_t fire)
{
        zfs_onexit_t *zo;
        zfs_onexit_action_node_t *ap;
        int error;

        error = zfs_onexit_minor_to_state(minor, &zo);
        if (error)
                return (error);

        mutex_enter(&zo->zo_lock);
        ap = zfs_onexit_find_cb(zo, action_handle);
        if (ap != NULL) {
                list_remove(&zo->zo_actions, ap);
                mutex_exit(&zo->zo_lock);
                if (fire)
                        ap->za_func(ap->za_data);
                kmem_free(ap, sizeof (zfs_onexit_action_node_t));
        } else {
                mutex_exit(&zo->zo_lock);
                error = ENOENT;
        }

        return (error);
}

int
zfs_onexit_cb_data(minor_t minor, uint64_t action_handle, void **data)
{
        zfs_onexit_t *zo;
        zfs_onexit_action_node_t *ap;
        int error;

        *data = NULL;

        error = zfs_onexit_minor_to_state(minor, &zo);
        if (error)
                return (error);

        mutex_enter(&zo->zo_lock);
        ap = zfs_onexit_find_cb(zo, action_handle);
        if (ap != NULL)
                *data = ap->za_data;
        else
                error = ENOENT;
        mutex_exit(&zo->zo_lock);

        return (error);
}