libses/common/ses_snap.c

/*
 * 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) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <scsi/libses.h>
#include "ses_impl.h"

ses_snap_page_t *
ses_snap_find_page(ses_snap_t *sp, ses2_diag_page_t page, boolean_t ctl)
{
    ses_snap_page_t *pp;

    for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next)
        if (pp->ssp_num == page && pp->ssp_control == ctl &&
            (pp->ssp_len > 0 || pp->ssp_control))
            return (pp);

    return (NULL);
}

static int
grow_snap_page(ses_snap_page_t *pp, size_t min)
{
    uint8_t *newbuf;

    if (min == 0 || min < pp->ssp_alloc)
        min = pp->ssp_alloc * 2;

    if ((newbuf = ses_realloc(pp->ssp_page, min)) == NULL)
        return (-1);

    pp->ssp_page = newbuf;
    pp->ssp_alloc = min;

    bzero(newbuf + pp->ssp_len, pp->ssp_alloc - pp->ssp_len);

    return (0);
}

static ses_snap_page_t *
alloc_snap_page(void)
{
    ses_snap_page_t *pp;

    if ((pp = ses_zalloc(sizeof (ses_snap_page_t))) == NULL)
        return (NULL);

    if ((pp->ssp_page = ses_zalloc(SES2_MIN_DIAGPAGE_ALLOC)) == NULL) {
        ses_free(pp);
        return (NULL);
    }

    pp->ssp_num = -1;
    pp->ssp_alloc = SES2_MIN_DIAGPAGE_ALLOC;

    return (pp);
}

static void
free_snap_page(ses_snap_page_t *pp)
{
    if (pp == NULL)
        return;

    if (pp->ssp_mmap_base)
        (void) munmap(pp->ssp_mmap_base, pp->ssp_mmap_len);
    else
        ses_free(pp->ssp_page);
    ses_free(pp);
}

static void
free_all_snap_pages(ses_snap_t *sp)
{
    ses_snap_page_t *pp, *np;

    for (pp = sp->ss_pages; pp != NULL; pp = np) {
        np = pp->ssp_next;
        free_snap_page(pp);
    }

    sp->ss_pages = NULL;
}

/*
 * Grow (if needed) the control page buffer, fill in the page code, page
 * length, and generation count, and return a pointer to the page.  The
 * caller is responsible for filling in the rest of the page data.  If 'unique'
 * is specified, then a new page instance is created instead of sharing the
 * current one.
 */
ses_snap_page_t *
ses_snap_ctl_page(ses_snap_t *sp, ses2_diag_page_t page, size_t dlen,
    boolean_t unique)
{
    ses_target_t *tp = sp->ss_target;
    spc3_diag_page_impl_t *pip;
    ses_snap_page_t *pp, *up, **loc;
    ses_pagedesc_t *dp;
    size_t len;

    pp = ses_snap_find_page(sp, page, B_TRUE);
    if (pp == NULL) {
        (void) ses_set_errno(ESES_NOTSUP);
        return (NULL);
    }

    if (pp->ssp_initialized && !unique)
        return (pp);

    if (unique) {
        /*
         * The user has requested a unique instance of the page.  Create
         * a new ses_snap_page_t instance and chain it off the
         * 'ssp_instances' list of the master page.  These must be
         * appended to the end of the chain, as the order of operations
         * may be important (i.e. microcode download).
         */
        if ((up = alloc_snap_page()) == NULL)
            return (NULL);

        up->ssp_num = pp->ssp_num;
        up->ssp_control = B_TRUE;

        for (loc = &pp->ssp_unique; *loc != NULL;
            loc = &(*loc)->ssp_next)
            ;

        *loc = up;
        pp = up;
    }

    dp = ses_get_pagedesc(tp, page, SES_PAGE_CTL);
    ASSERT(dp != NULL);

    len = dp->spd_ctl_len(sp->ss_n_elem, page, dlen);
    if (pp->ssp_alloc < len && grow_snap_page(pp, len) != 0)
        return (NULL);
    pp->ssp_len = len;
    bzero(pp->ssp_page, len);
    pp->ssp_initialized = B_TRUE;

    pip = (spc3_diag_page_impl_t *)pp->ssp_page;
    pip->sdpi_page_code = (uint8_t)page;
    SCSI_WRITE16(&pip->sdpi_page_length,
        len - offsetof(spc3_diag_page_impl_t, sdpi_data[0]));
    if (dp->spd_gcoff != -1)
        SCSI_WRITE32((uint8_t *)pip + dp->spd_gcoff, sp->ss_generation);

    return (pp);
}

static int
read_status_page(ses_snap_t *sp, ses2_diag_page_t page)
{
    libscsi_action_t *ap;
    ses_snap_page_t *pp;
    ses_target_t *tp;
    spc3_diag_page_impl_t *pip;
    spc3_receive_diagnostic_results_cdb_t *cp;
    uint_t flags;
    uint8_t *buf;
    size_t alloc;
    uint_t retries = 0;
    ses2_diag_page_t retpage;

    for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next)
        if (pp->ssp_num == page && !pp->ssp_control)
            break;

    /*
     * No matching page.  Since the page number is not under consumer or
     * device control, this must be a bug.
     */
    ASSERT(pp != NULL);

    tp = sp->ss_target;

    flags = LIBSCSI_AF_READ | LIBSCSI_AF_SILENT | LIBSCSI_AF_DIAGNOSE |
        LIBSCSI_AF_RQSENSE;

again:
    ap = libscsi_action_alloc(tp->st_scsi_hdl,
        SPC3_CMD_RECEIVE_DIAGNOSTIC_RESULTS, flags, pp->ssp_page,
        pp->ssp_alloc);

    if (ap == NULL)
        return (ses_libscsi_error(tp->st_scsi_hdl, "failed to "
            "allocate SCSI action"));

    cp = (spc3_receive_diagnostic_results_cdb_t *)
        libscsi_action_get_cdb(ap);

    cp->rdrc_page_code = pp->ssp_num;
    cp->rdrc_pcv = 1;
    SCSI_WRITE16(&cp->rdrc_allocation_length,
        MIN(pp->ssp_alloc, UINT16_MAX));

    if (libscsi_exec(ap, tp->st_target) != 0) {
        libscsi_action_free(ap);
        return (ses_libscsi_error(tp->st_scsi_hdl,
            "receive diagnostic results failed"));
    }

    if (libscsi_action_get_status(ap) != 0) {
        (void) ses_scsi_error(ap,
            "receive diagnostic results failed");
        libscsi_action_free(ap);
        return (-1);
    }

    (void) libscsi_action_get_buffer(ap, &buf, &alloc, &pp->ssp_len);
    libscsi_action_free(ap);

    ASSERT(buf == pp->ssp_page);
    ASSERT(alloc == pp->ssp_alloc);

    if (pp->ssp_alloc - pp->ssp_len < 0x80 && pp->ssp_alloc < UINT16_MAX) {
        bzero(pp->ssp_page, pp->ssp_len);
        pp->ssp_len = 0;
        if (grow_snap_page(pp, 0) != 0)
            return (-1);
        goto again;
    }

    if (pp->ssp_len < offsetof(spc3_diag_page_impl_t, sdpi_data)) {
        bzero(pp->ssp_page, pp->ssp_len);
        pp->ssp_len = 0;
        return (ses_error(ESES_BAD_RESPONSE, "target returned "
            "truncated page 0x%x (length %d)", page, pp->ssp_len));
    }

    pip = (spc3_diag_page_impl_t *)buf;

    if (pip->sdpi_page_code == page)
        return (0);

    retpage = pip->sdpi_page_code;

    bzero(pp->ssp_page, pp->ssp_len);
    pp->ssp_len = 0;

    if (retpage == SES2_DIAGPAGE_ENCLOSURE_BUSY) {
        if (++retries > LIBSES_MAX_BUSY_RETRIES)
            return (ses_error(ESES_BUSY, "too many "
                "enclosure busy responses for page 0x%x", page));
        goto again;
    }

    return (ses_error(ESES_BAD_RESPONSE, "target returned page 0x%x "
        "instead of the requested page 0x%x", retpage, page));
}

static int
send_control_page(ses_snap_t *sp, ses_snap_page_t *pp)
{
    ses_target_t *tp;
    libscsi_action_t *ap;
    spc3_send_diagnostic_cdb_t *cp;
    uint_t flags;

    tp = sp->ss_target;

    flags = LIBSCSI_AF_WRITE | LIBSCSI_AF_SILENT | LIBSCSI_AF_DIAGNOSE |
        LIBSCSI_AF_RQSENSE;

    ap = libscsi_action_alloc(tp->st_scsi_hdl, SPC3_CMD_SEND_DIAGNOSTIC,
        flags, pp->ssp_page, pp->ssp_len);

    if (ap == NULL)
        return (ses_libscsi_error(tp->st_scsi_hdl, "failed to "
            "allocate SCSI action"));

    cp = (spc3_send_diagnostic_cdb_t *)libscsi_action_get_cdb(ap);

    cp->sdc_pf = 1;
    SCSI_WRITE16(&cp->sdc_parameter_list_length, pp->ssp_len);

    if (libscsi_exec(ap, tp->st_target) != 0) {
        libscsi_action_free(ap);
        return (ses_libscsi_error(tp->st_scsi_hdl,
            "SEND DIAGNOSTIC command failed for page 0x%x",
            pp->ssp_num));
    }

    if (libscsi_action_get_status(ap) != 0) {
        (void) ses_scsi_error(ap, "SEND DIAGNOSTIC command "
            "failed for page 0x%x", pp->ssp_num);
        libscsi_action_free(ap);
        return (-1);
    }

    libscsi_action_free(ap);

    return (0);
}

static int
pages_skel_create(ses_snap_t *sp)
{
    ses_snap_page_t *pp, *np;
    ses_target_t *tp = sp->ss_target;
    ses2_supported_ses_diag_page_impl_t *pip;
    ses2_diag_page_t page;
    size_t npages;
    size_t pagelen;
    off_t i;

    ASSERT(sp->ss_pages == NULL);

    if ((pp = alloc_snap_page()) == NULL)
        return (-1);

    pp->ssp_num = SES2_DIAGPAGE_SUPPORTED_PAGES;
    pp->ssp_control = B_FALSE;
    sp->ss_pages = pp;

    if (read_status_page(sp, SES2_DIAGPAGE_SUPPORTED_PAGES) != 0) {
        free_snap_page(pp);
        sp->ss_pages = NULL;
        return (-1);
    }

    pip = pp->ssp_page;
    pagelen = pp->ssp_len;

    npages = SCSI_READ16(&pip->sssdpi_page_length);

    for (i = 0; i < npages; i++) {
        if (!SES_WITHIN_PAGE(pip->sssdpi_pages + i, 1, pip,
            pagelen))
            break;

        page = (ses2_diag_page_t)pip->sssdpi_pages[i];
        /*
         * Skip the page we already added during the bootstrap.
         */
        if (page == SES2_DIAGPAGE_SUPPORTED_PAGES)
            continue;
        /*
         * The end of the page list may be padded with zeros; ignore
         * them all.
         */
        if (page == 0 && i > 0)
            break;
        if ((np = alloc_snap_page()) == NULL) {
            free_all_snap_pages(sp);
            return (-1);
        }
        np->ssp_num = page;
        pp->ssp_next = np;
        pp = np;

        /*
         * Allocate a control page as well, if we can use it.
         */
        if (ses_get_pagedesc(tp, page, SES_PAGE_CTL) != NULL) {
            if ((np = alloc_snap_page()) == NULL) {
                free_all_snap_pages(sp);
                return (-1);
            }
            np->ssp_num = page;
            np->ssp_control = B_TRUE;
            pp->ssp_next = np;
            pp = np;
        }
    }

    return (0);
}

static void
ses_snap_free(ses_snap_t *sp)
{
    free_all_snap_pages(sp);
    ses_node_teardown(sp->ss_root);
    ses_free(sp->ss_nodes);
    ses_free(sp);
}

static void
ses_snap_rele_unlocked(ses_snap_t *sp)
{
    ses_target_t *tp = sp->ss_target;

    if (--sp->ss_refcnt != 0)
        return;

    if (sp->ss_next != NULL)
        sp->ss_next->ss_prev = sp->ss_prev;

    if (sp->ss_prev != NULL)
        sp->ss_prev->ss_next = sp->ss_next;
    else
        tp->st_snapshots = sp->ss_next;

    ses_snap_free(sp);
}

ses_snap_t *
ses_snap_hold(ses_target_t *tp)
{
    ses_snap_t *sp;

    (void) pthread_mutex_lock(&tp->st_lock);
    sp = tp->st_snapshots;
    sp->ss_refcnt++;
    (void) pthread_mutex_unlock(&tp->st_lock);

    return (sp);
}

void
ses_snap_rele(ses_snap_t *sp)
{
    ses_target_t *tp = sp->ss_target;

    (void) pthread_mutex_lock(&tp->st_lock);
    ses_snap_rele_unlocked(sp);
    (void) pthread_mutex_unlock(&tp->st_lock);
}

ses_snap_t *
ses_snap_new(ses_target_t *tp)
{
    ses_snap_t *sp;
    ses_snap_page_t *pp;
    uint32_t gc;
    uint_t retries = 0;
    ses_pagedesc_t *dp;
    size_t pages, pagesize, pagelen;
    char *scratch;
    boolean_t simple;

    if ((sp = ses_zalloc(sizeof (ses_snap_t))) == NULL)
        return (NULL);

    sp->ss_target = tp;

again:
    free_all_snap_pages(sp);

    if (pages_skel_create(sp) != 0) {
        free(sp);
        return (NULL);
    }

    sp->ss_generation = (uint32_t)-1;
    sp->ss_time = gethrtime();

    /*
     * First check for the short enclosure status diagnostic page and
     * determine if this is a simple subenclosure or not.
     */
    simple = B_FALSE;
    for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next) {
        if (pp->ssp_num == SES2_DIAGPAGE_SHORT_STATUS)
            simple = B_TRUE;
    }

    for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next) {
        /*
         * We skip all of:
         *
         * - Control pages
         * - Pages we've already filled in
         * - Pages we don't understand (those with no descriptor)
         */
        if (pp->ssp_len > 0 || pp->ssp_control)
            continue;
        if ((dp = ses_get_pagedesc(tp, pp->ssp_num,
            SES_PAGE_DIAG)) == NULL)
            continue;

        if (read_status_page(sp, pp->ssp_num) != 0)  {
            /*
             * If this page is required, and this is not a simple
             * subenclosure, then fail the entire snapshot.
             */
            if (dp->spd_req == SES_REQ_MANDATORY_ALL ||
                (dp->spd_req == SES_REQ_MANDATORY_STANDARD &&
                !simple)) {
                ses_snap_free(sp);
                return (NULL);
            }

            continue;
        }

        /*
         * If the generation code has changed, we don't have a valid
         * snapshot.  Start over.
         */
        if (dp->spd_gcoff != -1 &&
            dp->spd_gcoff + 4 <= pp->ssp_len) {
            gc = SCSI_READ32((uint8_t *)pp->ssp_page +
                dp->spd_gcoff);
            if (sp->ss_generation == (uint32_t)-1) {
                sp->ss_generation = gc;
            } else if (sp->ss_generation != gc) {
                if (++retries > LIBSES_MAX_GC_RETRIES) {
                    (void) ses_error(ESES_TOOMUCHCHANGE,
                        "too many generation count "
                        "mismatches: page 0x%x gc %u "
                        "previous page %u", dp->spd_gcoff,
                        gc, sp->ss_generation);
                    ses_snap_free((ses_snap_t *)sp);
                    return (NULL);
                }
                goto again;
            }
        }
    }

    /*
     * The LIBSES_TRUNCATE environment variable is a debugging tool which,
     * if set, randomly truncates all pages (except
     * SES2_DIAGPAGE_SUPPORTED_PAGES).  In order to be truly evil, we
     * mmap() each page with enough space after it so we can move the data
     * up to the end of a page and unmap the following page so that any
     * attempt to read past the end of the page results in a segfault.
     */
    if (sp->ss_target->st_truncate) {
        pagesize = PAGESIZE;

        /*
         * Count the maximum number of pages we will need and allocate
         * the necessary space.
         */
        pages = 0;
        for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next) {
            if (pp->ssp_control || pp->ssp_len == 0)
                continue;

            pages += (P2ROUNDUP(pp->ssp_len, pagesize) /
                pagesize) + 1;
        }

        if ((scratch = mmap(NULL, pages * pagesize,
            PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE,
            -1, 0)) == MAP_FAILED) {
            (void) ses_error(ESES_NOMEM,
                "failed to mmap() pages for truncation");
            ses_snap_free(sp);
            return (NULL);
        }

        for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next) {
            if (pp->ssp_control || pp->ssp_len == 0)
                continue;

            pages = P2ROUNDUP(pp->ssp_len, pagesize) / pagesize;
            pp->ssp_mmap_base = scratch;
            pp->ssp_mmap_len = pages * pagesize;

            pagelen = lrand48() % pp->ssp_len;
            (void) memcpy(pp->ssp_mmap_base + pp->ssp_mmap_len -
                pagelen, pp->ssp_page, pagelen);
            ses_free(pp->ssp_page);
            pp->ssp_page = pp->ssp_mmap_base + pp->ssp_mmap_len -
                pagelen;
            pp->ssp_len = pagelen;

            (void) munmap(pp->ssp_mmap_base + pages * pagesize,
                pagesize);
            scratch += (pages + 1) * pagesize;
        }
    }


    if (ses_fill_snap(sp) != 0) {
        ses_snap_free(sp);
        return (NULL);
    }

    (void) pthread_mutex_lock(&tp->st_lock);
    if (tp->st_snapshots != NULL)
        ses_snap_rele_unlocked(tp->st_snapshots);
    sp->ss_next = tp->st_snapshots;
    if (tp->st_snapshots != NULL)
        tp->st_snapshots->ss_prev = sp;
    tp->st_snapshots = sp;
    sp->ss_refcnt = 2;
    (void) pthread_mutex_unlock(&tp->st_lock);

    return (sp);
}

int
ses_snap_do_ctl(ses_snap_t *sp)
{
    ses_snap_page_t *pp, *up;
    int ret = -1;

    for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next) {
        if (!pp->ssp_control)
            continue;

        if (pp->ssp_initialized && send_control_page(sp, pp) != 0)
            goto error;

        for (up = pp->ssp_unique; up != NULL; up = up->ssp_next) {
            if (send_control_page(sp, up) != 0)
                goto error;
        }
    }

    ret = 0;
error:
    for (pp = sp->ss_pages; pp != NULL; pp = pp->ssp_next) {
        if (!pp->ssp_control)
            continue;

        pp->ssp_initialized = B_FALSE;
        while ((up = pp->ssp_unique) != NULL) {
            pp->ssp_unique = up->ssp_next;
            free_snap_page(up);
        }
    }


    return (ret);
}

uint32_t
ses_snap_generation(ses_snap_t *sp)
{
    return (sp->ss_generation);
}

static ses_walk_action_t
ses_walk_node(ses_node_t *np, ses_walk_f func, void *arg)
{
    ses_walk_action_t action;

    for (; np != NULL; np = ses_node_sibling(np)) {
        action = func(np, arg);
        if (action == SES_WALK_ACTION_TERMINATE)
            return (SES_WALK_ACTION_TERMINATE);
        if (action == SES_WALK_ACTION_PRUNE ||
            ses_node_child(np) == NULL)
            continue;
        if (ses_walk_node(ses_node_child(np), func, arg) ==
            SES_WALK_ACTION_TERMINATE)
            return (SES_WALK_ACTION_TERMINATE);
    }

    return (SES_WALK_ACTION_CONTINUE);
}

int
ses_walk(ses_snap_t *sp, ses_walk_f func, void *arg)
{
    (void) ses_walk_node(ses_root_node(sp), func, arg);

    return (0);
}

/*ARGSUSED*/
static ses_walk_action_t
ses_fill_nodes(ses_node_t *np, void *unused)
{
    np->sn_snapshot->ss_nodes[np->sn_id] = np;

    return (SES_WALK_ACTION_CONTINUE);
}

/*
 * Given an ID returned by ses_node_id(), lookup and return the corresponding
 * node in the snapshot.  If the snapshot generation count has changed, then
 * return failure.
 */
ses_node_t *
ses_node_lookup(ses_snap_t *sp, uint64_t id)
{
    uint32_t gen = (id >> 32);
    uint32_t idx = (id & 0xFFFFFFFF);

    if (sp->ss_generation != gen) {
        (void) ses_set_errno(ESES_CHANGED);
        return (NULL);
    }

    if (idx >= sp->ss_n_nodes) {
        (void) ses_error(ESES_BAD_NODE,
            "no such node in snapshot");
        return (NULL);
    }

    /*
     * If this is our first lookup attempt, construct the array for fast
     * lookups.
     */
    if (sp->ss_nodes == NULL) {
        if ((sp->ss_nodes = ses_zalloc(
            sp->ss_n_nodes * sizeof (void *))) == NULL)
            return (NULL);

        (void) ses_walk(sp, ses_fill_nodes, NULL);
    }

    if (sp->ss_nodes[idx] == NULL)
        (void) ses_error(ESES_BAD_NODE,
            "no such node in snapshot");
    return (sp->ss_nodes[idx]);
}