fs/zfs/dsl_prop.c

	dsl_prop.c revision fa9e4066f08beec538e775443c5be79dd423fcab
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/dmu.h>
#include <sys/dmu_tx.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_prop.h>
#include <sys/spa.h>
#include <sys/zio_checksum.h> /* for the default checksum value */
#include <sys/zap.h>
#include <sys/fs/zfs.h>

#include "zfs_prop.h"

static int
dodefault(const char *propname, int intsz, int numint, void *buf)
{
    zfs_prop_t prop;

    if ((prop = zfs_name_to_prop(propname)) == ZFS_PROP_INVAL ||
        zfs_prop_readonly(prop))
        return (ENOENT);

    if (zfs_prop_get_type(prop) == prop_type_string) {
        if (intsz != 1)
            return (EOVERFLOW);
        zfs_prop_default_string(prop, buf, numint);
    } else {
        if (intsz != 8 || numint < 1)
            return (EOVERFLOW);

        *(uint64_t *)buf = zfs_prop_default_numeric(prop);
    }

    return (0);
}

static int
dsl_prop_get_impl(dsl_pool_t *dp, uint64_t ddobj, const char *propname,
    int intsz, int numint, void *buf, char *setpoint)
{
    int err = 0;
    objset_t *mos = dp->dp_meta_objset;

    if (setpoint)
        setpoint[0] = '\0';

    ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock));

    while (ddobj != 0) {
        dsl_dir_t *dd = dsl_dir_open_obj(dp, ddobj, NULL, FTAG);
        err = zap_lookup(mos, dd->dd_phys->dd_props_zapobj,
            propname, intsz, numint, buf);
        if (err != ENOENT) {
            if (setpoint)
                dsl_dir_name(dd, setpoint);
            dsl_dir_close(dd, FTAG);
            break;
        }
        ASSERT3U(err, ==, ENOENT);
        ddobj = dd->dd_phys->dd_parent_obj;
        dsl_dir_close(dd, FTAG);
    }
    if (err == ENOENT)
        err = dodefault(propname, intsz, numint, buf);

    return (err);
}

/*
 * Register interest in the named property.  We'll call the callback
 * once to notify it of the current property value, and again each time
 * the property changes, until this callback is unregistered.
 *
 * Return 0 on success, errno if the prop is not an integer value.
 */
int
dsl_prop_register(dsl_dataset_t *ds, const char *propname,
    dsl_prop_changed_cb_t *callback, void *cbarg)
{
    dsl_dir_t *dd;
    uint64_t value;
    dsl_prop_cb_record_t *cbr;
    int err;

    dd = ds->ds_dir;

    rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);

    err = dsl_prop_get_impl(dd->dd_pool, dd->dd_object, propname,
        8, 1, &value, NULL);
    if (err == ENOENT) {
        err = 0;
        value = DSL_PROP_VALUE_UNDEFINED;
    }
    if (err != 0) {
        rw_exit(&dd->dd_pool->dp_config_rwlock);
        return (err);
    }

    cbr = kmem_alloc(sizeof (dsl_prop_cb_record_t), KM_SLEEP);
    cbr->cbr_propname = kmem_alloc(strlen(propname)+1, KM_SLEEP);
    (void) strcpy((char *)cbr->cbr_propname, propname);
    cbr->cbr_func = callback;
    cbr->cbr_arg = cbarg;
    mutex_enter(&dd->dd_lock);
    list_insert_head(&dd->dd_prop_cbs, cbr);
    mutex_exit(&dd->dd_lock);

    cbr->cbr_func(cbr->cbr_arg, value);

    (void) dsl_dir_open_obj(dd->dd_pool, dd->dd_object, NULL, cbr);
    rw_exit(&dd->dd_pool->dp_config_rwlock);
    /* Leave dataset open until this callback is unregistered */
    return (0);
}

int
dsl_prop_get_ds(dsl_dir_t *dd, const char *propname,
    int intsz, int numints, void *buf, char *setpoint)
{
    int err;

    rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
    err = dsl_prop_get_impl(dd->dd_pool, dd->dd_object,
        propname, intsz, numints, buf, setpoint);
    rw_exit(&dd->dd_pool->dp_config_rwlock);

    return (err);
}

int
dsl_prop_get(const char *ddname, const char *propname,
    int intsz, int numints, void *buf, char *setpoint)
{
    dsl_dir_t *dd;
    const char *tail;
    int err;

    dd = dsl_dir_open(ddname, FTAG, &tail);
    if (dd == NULL)
        return (ENOENT);
    if (tail && tail[0] != '@') {
        dsl_dir_close(dd, FTAG);
        return (ENOENT);
    }

    err = dsl_prop_get_ds(dd, propname, intsz, numints, buf, setpoint);

    dsl_dir_close(dd, FTAG);
    return (err);
}

/*
 * Return 0 on success, ENOENT if ddname is invalid, EOVERFLOW if
 * valuelen not big enough.
 */
int
dsl_prop_get_string(const char *ddname, const char *propname,
    char *value, int valuelen, char *setpoint)
{
    return (dsl_prop_get(ddname, propname, 1, valuelen, value, setpoint));
}

/*
 * Get the current property value.  It may have changed by the time this
 * function returns, so it is NOT safe to follow up with
 * dsl_prop_register() and assume that the value has not changed in
 * between.
 *
 * Return 0 on success, ENOENT if ddname is invalid.
 */
int
dsl_prop_get_integer(const char *ddname, const char *propname,
    uint64_t *valuep, char *setpoint)
{
    return (dsl_prop_get(ddname, propname, 8, 1, valuep, setpoint));
}

int
dsl_prop_get_ds_integer(dsl_dir_t *dd, const char *propname,
    uint64_t *valuep, char *setpoint)
{
    return (dsl_prop_get_ds(dd, propname, 8, 1, valuep, setpoint));
}

/*
 * Unregister this callback.  Return 0 on success, ENOENT if ddname is
 * invalid, ENOMSG if no matching callback registered.
 */
int
dsl_prop_unregister(dsl_dataset_t *ds, const char *propname,
    dsl_prop_changed_cb_t *callback, void *cbarg)
{
    dsl_dir_t *dd;
    dsl_prop_cb_record_t *cbr;

    dd = ds->ds_dir;

    mutex_enter(&dd->dd_lock);
    for (cbr = list_head(&dd->dd_prop_cbs);
        cbr; cbr = list_next(&dd->dd_prop_cbs, cbr)) {
        if (strcmp(cbr->cbr_propname, propname) == 0 &&
            cbr->cbr_func == callback &&
            cbr->cbr_arg == cbarg)
            break;
    }

    if (cbr == NULL) {
        mutex_exit(&dd->dd_lock);
        return (ENOMSG);
    }

    list_remove(&dd->dd_prop_cbs, cbr);
    mutex_exit(&dd->dd_lock);
    kmem_free((void*)cbr->cbr_propname, strlen(cbr->cbr_propname)+1);
    kmem_free(cbr, sizeof (dsl_prop_cb_record_t));

    /* Clean up from dsl_prop_register */
    dsl_dir_close(dd, cbr);
    return (0);
}

static void
dsl_prop_changed_notify(dsl_pool_t *dp, uint64_t ddobj,
    const char *propname, uint64_t value, int first)
{
    dsl_dir_t *dd;
    dsl_prop_cb_record_t *cbr;
    objset_t *mos = dp->dp_meta_objset;
    int err;

    ASSERT(RW_WRITE_HELD(&dp->dp_config_rwlock));
    dd = dsl_dir_open_obj(dp, ddobj, NULL, FTAG);

    if (!first) {
        /*
         * If the prop is set here, then this change is not
         * being inherited here or below; stop the recursion.
         */
        err = zap_lookup(mos, dd->dd_phys->dd_props_zapobj, propname,
            8, 1, &value);
        if (err == 0) {
            dsl_dir_close(dd, FTAG);
            return;
        }
        ASSERT3U(err, ==, ENOENT);
    }

    mutex_enter(&dd->dd_lock);
    for (cbr = list_head(&dd->dd_prop_cbs);
        cbr; cbr = list_next(&dd->dd_prop_cbs, cbr)) {
        if (strcmp(cbr->cbr_propname, propname) == 0) {
            cbr->cbr_func(cbr->cbr_arg, value);
        }
    }
    mutex_exit(&dd->dd_lock);

    if (dd->dd_phys->dd_child_dir_zapobj) {
        zap_cursor_t zc;
        zap_attribute_t za;

        for (zap_cursor_init(&zc, mos,
            dd->dd_phys->dd_child_dir_zapobj);
            zap_cursor_retrieve(&zc, &za) == 0;
            zap_cursor_advance(&zc)) {
            /* XXX recursion could blow stack; esp. za! */
            dsl_prop_changed_notify(dp, za.za_first_integer,
                propname, value, FALSE);
        }
    }
    dsl_dir_close(dd, FTAG);
}

struct prop_set_arg {
    const char *name;
    int intsz;
    int numints;
    const void *buf;
};

static int
dsl_prop_set_sync(dsl_dir_t *dd, void *arg, dmu_tx_t *tx)
{
    struct prop_set_arg *psa = arg;
    objset_t *mos = dd->dd_pool->dp_meta_objset;
    uint64_t zapobj = dd->dd_phys->dd_props_zapobj;
    uint64_t intval;
    int err, isint;

    rw_enter(&dd->dd_pool->dp_config_rwlock, RW_WRITER);

    isint = (dodefault(psa->name, 8, 1, &intval) == 0);

    if (psa->numints == 0) {
        err = zap_remove(mos, zapobj, psa->name, tx);
        if (err == ENOENT) /* that's fine. */
            err = 0;
        if (err == 0 && isint) {
            err = dsl_prop_get_impl(dd->dd_pool,
                dd->dd_phys->dd_parent_obj, psa->name,
                8, 1, &intval, NULL);
        }
    } else {
        err = zap_update(mos, zapobj, psa->name,
            psa->intsz, psa->numints, psa->buf, tx);
        if (isint)
            intval = *(uint64_t *)psa->buf;
    }

    if (err == 0 && isint) {
        dsl_prop_changed_notify(dd->dd_pool,
            dd->dd_object, psa->name, intval, TRUE);
    }
    rw_exit(&dd->dd_pool->dp_config_rwlock);

    return (err);
}

int
dsl_prop_set(const char *ddname, const char *propname,
    int intsz, int numints, const void *buf)
{
    dsl_dir_t *dd;
    int err;
    struct prop_set_arg psa;

    dd = dsl_dir_open(ddname, FTAG, NULL);
    if (dd == NULL)
        return (ENOENT);

    psa.name = propname;
    psa.intsz = intsz;
    psa.numints = numints;
    psa.buf = buf;
    err = dsl_dir_sync_task(dd, dsl_prop_set_sync, &psa, 0);

    dsl_dir_close(dd, FTAG);

    return (err);
}