fs/zfs/dsl_prop.c

	dsl_prop.c revision e9dbad6f263d5570ed7ff5443ec5b958af8c24d7
/*
 * 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 2006 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_objset.h>
#include <sys/dmu_tx.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_prop.h>
#include <sys/dsl_synctask.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);
        (void) strncpy(buf, zfs_prop_default_string(prop), 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_dir_t *dd, const char *propname,
    int intsz, int numint, void *buf, char *setpoint)
{
    int err = ENOENT;
    zfs_prop_t prop;

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

    prop = zfs_name_to_prop(propname);

    /*
     * Note: dd may be NULL, therefore we shouldn't dereference it
     * ouside this loop.
     */
    for (; dd != NULL; dd = dd->dd_parent) {
        objset_t *mos = dd->dd_pool->dp_meta_objset;
        ASSERT(RW_LOCK_HELD(&dd->dd_pool->dp_config_rwlock));
        err = zap_lookup(mos, dd->dd_phys->dd_props_zapobj,
            propname, intsz, numint, buf);
        if (err != ENOENT) {
            if (setpoint)
                dsl_dir_name(dd, setpoint);
            break;
        }

        /*
         * Break out of this loop for non-inheritable properties.
         */
        if (prop != ZFS_PROP_INVAL &&
            !zfs_prop_inheritable(prop))
            break;
    }
    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 = ds->ds_dir;
    uint64_t value;
    dsl_prop_cb_record_t *cbr;
    int err;
    int need_rwlock;

    need_rwlock = !RW_WRITE_HELD(&dd->dd_pool->dp_config_rwlock);
    if (need_rwlock)
        rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);

    err = dsl_prop_get_impl(dd, propname, 8, 1, &value, NULL);
    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_ds = ds;
    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);

    VERIFY(0 == dsl_dir_open_obj(dd->dd_pool, dd->dd_object,
        NULL, cbr, &dd));
    if (need_rwlock)
        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, 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;

    err = dsl_dir_open(ddname, FTAG, &dd, &tail);
    if (err)
        return (err);
    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 = ds->ds_dir;
    dsl_prop_cb_record_t *cbr;

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

/*
 * Return the number of callbacks that are registered for this dataset.
 */
int
dsl_prop_numcb(dsl_dataset_t *ds)
{
    dsl_dir_t *dd = ds->ds_dir;
    dsl_prop_cb_record_t *cbr;
    int num = 0;

    mutex_enter(&dd->dd_lock);
    for (cbr = list_head(&dd->dd_prop_cbs);
        cbr; cbr = list_next(&dd->dd_prop_cbs, cbr)) {
        if (cbr->cbr_ds == ds)
            num++;
    }
    mutex_exit(&dd->dd_lock);

    return (num);
}

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;
    zap_cursor_t zc;
    zap_attribute_t za;
    int err;

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

    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);

    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);
    }
    zap_cursor_fini(&zc);
    dsl_dir_close(dd, FTAG);
}

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


static void
dsl_prop_set_sync(void *arg1, void *arg2, dmu_tx_t *tx)
{
    dsl_dir_t *dd = arg1;
    struct prop_set_arg *psa = arg2;
    objset_t *mos = dd->dd_pool->dp_meta_objset;
    uint64_t zapobj = dd->dd_phys->dd_props_zapobj;
    uint64_t intval;
    int isint;

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

    if (psa->numints == 0) {
        int err = zap_remove(mos, zapobj, psa->name, tx);
        ASSERT(err == 0 || err == ENOENT);
        if (isint) {
            VERIFY(0 == dsl_prop_get_impl(dd->dd_parent,
                psa->name, 8, 1, &intval, NULL));
        }
    } else {
        VERIFY(0 == zap_update(mos, zapobj, psa->name,
            psa->intsz, psa->numints, psa->buf, tx));
        if (isint)
            intval = *(uint64_t *)psa->buf;
    }

    if (isint) {
        dsl_prop_changed_notify(dd->dd_pool,
            dd->dd_object, psa->name, intval, TRUE);
    }
}

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;

    /*
     * We must do these checks before we get to the syncfunc, since
     * it can't fail.
     */
    if (strlen(propname) >= ZAP_MAXNAMELEN)
        return (ENAMETOOLONG);
    if (intsz * numints >= ZAP_MAXVALUELEN)
        return (E2BIG);

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

    psa.name = propname;
    psa.intsz = intsz;
    psa.numints = numints;
    psa.buf = buf;
    err = dsl_sync_task_do(dd->dd_pool,
        NULL, dsl_prop_set_sync, dd, &psa, 2);

    dsl_dir_close(dd, FTAG);

    return (err);
}

/*
 * Iterate over all properties for this dataset and return them in an nvlist.
 */
int
dsl_prop_get_all(objset_t *os, nvlist_t **nvp)
{
    dsl_dataset_t *ds = os->os->os_dsl_dataset;
    dsl_dir_t *dd = ds->ds_dir;
    int err = 0;
    dsl_pool_t *dp;
    objset_t *mos;
    zap_cursor_t zc;
    zap_attribute_t za;
    char setpoint[MAXNAMELEN];
    char *tmp;
    nvlist_t *propval;
    zfs_prop_t prop;

    if (dsl_dataset_is_snapshot(ds)) {
        VERIFY(nvlist_alloc(nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);
        return (0);
    }

    VERIFY(nvlist_alloc(nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);

    dp = dd->dd_pool;
    mos = dp->dp_meta_objset;

    rw_enter(&dp->dp_config_rwlock, RW_READER);
    for (; dd != NULL; dd = dd->dd_parent) {
        dsl_dir_name(dd, setpoint);

        for (zap_cursor_init(&zc, mos, dd->dd_phys->dd_props_zapobj);
            (err = zap_cursor_retrieve(&zc, &za)) == 0;
            zap_cursor_advance(&zc)) {
            /*
             * Skip non-inheritable properties.
             */
            if ((prop = zfs_name_to_prop(za.za_name)) !=
                ZFS_PROP_INVAL && !zfs_prop_inheritable(prop) &&
                dd != ds->ds_dir)
                continue;

            if (nvlist_lookup_nvlist(*nvp, za.za_name,
                &propval) == 0)
                continue;

            VERIFY(nvlist_alloc(&propval, NV_UNIQUE_NAME,
                KM_SLEEP) == 0);
            if (za.za_integer_length == 1) {
                /*
                 * String property
                 */
                tmp = kmem_alloc(za.za_num_integers, KM_SLEEP);
                err = zap_lookup(mos,
                    dd->dd_phys->dd_props_zapobj,
                    za.za_name, 1, za.za_num_integers,
                    tmp);
                if (err != 0) {
                    kmem_free(tmp, za.za_num_integers);
                    break;
                }
                VERIFY(nvlist_add_string(propval,
                    ZFS_PROP_VALUE, tmp) == 0);
                kmem_free(tmp, za.za_num_integers);
            } else {
                /*
                 * Integer property
                 */
                ASSERT(za.za_integer_length == 8);
                (void) nvlist_add_uint64(propval,
                    ZFS_PROP_VALUE, za.za_first_integer);
            }

            VERIFY(nvlist_add_string(propval,
                ZFS_PROP_SOURCE, setpoint) == 0);
            VERIFY(nvlist_add_nvlist(*nvp, za.za_name,
                propval) == 0);
            nvlist_free(propval);
        }
        zap_cursor_fini(&zc);

        if (err != ENOENT)
            break;
        err = 0;
    }
    rw_exit(&dp->dp_config_rwlock);

    return (err);
}