common/cpr/cpr_misc.c

	cpr_misc.c revision ae115bc77f6fcde83175c75b4206dc2e50747966
/*
 * 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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/cpuvar.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/pathname.h>
#include <sys/callb.h>
#include <sys/fs/ufs_inode.h>
#include <vm/anon.h>
#include <sys/fs/swapnode.h>    /* for swapfs_minfree */
#include <sys/kmem.h>
#include <sys/cpr.h>
#include <sys/conf.h>

/*
 * CPR miscellaneous support routines
 */
#define cpr_open(path, mode,  vpp)  (vn_open(path, UIO_SYSSPACE, \
        mode, 0600, vpp, CRCREAT, 0))
#define cpr_rdwr(rw, vp, basep, cnt)    (vn_rdwr(rw, vp,  (caddr_t)(basep), \
        cnt, 0LL, UIO_SYSSPACE, 0, (rlim64_t)MAXOFF_T, CRED(), \
        (ssize_t *)NULL))

extern void clkset(time_t);
extern cpu_t *i_cpr_bootcpu(void);
extern caddr_t i_cpr_map_setup(void);
extern void i_cpr_free_memory_resources(void);

extern kmutex_t cpr_slock;
extern size_t cpr_buf_size;
extern char *cpr_buf;
extern size_t cpr_pagedata_size;
extern char *cpr_pagedata;
extern int cpr_bufs_allocated;
extern int cpr_bitmaps_allocated;

static struct cprconfig cprconfig;
static int cprconfig_loaded = 0;
static int cpr_statefile_ok(vnode_t *, int);
static int cpr_p_online(cpu_t *, int);
static void cpr_save_mp_state(void);
int cpr_is_ufs(struct vfs *);

char cpr_default_path[] = CPR_DEFAULT;

#define COMPRESS_PERCENT 40 /* approx compression ratio in percent */
#define SIZE_RATE   115 /* increase size by 15% */
#define INTEGRAL    100 /* for integer math */


/*
 * cmn_err() followed by a 1/4 second delay; this gives the
 * logging service a chance to flush messages and helps avoid
 * intermixing output from prom_printf().
 */
/*PRINTFLIKE2*/
void
cpr_err(int ce, const char *fmt, ...)
{
    va_list adx;

    va_start(adx, fmt);
    vcmn_err(ce, fmt, adx);
    va_end(adx);
    drv_usecwait(MICROSEC >> 2);
}


int
cpr_init(int fcn)
{
    /*
     * Allow only one suspend/resume process.
     */
    if (mutex_tryenter(&cpr_slock) == 0)
        return (EBUSY);

    CPR->c_flags = 0;
    CPR->c_substate = 0;
    CPR->c_cprboot_magic = 0;
    CPR->c_alloc_cnt = 0;

    CPR->c_fcn = fcn;
    if (fcn == AD_CPR_REUSABLE)
        CPR->c_flags |= C_REUSABLE;
    else
        CPR->c_flags |= C_SUSPENDING;
    if (fcn != AD_CPR_NOCOMPRESS && fcn != AD_CPR_TESTNOZ)
        CPR->c_flags |= C_COMPRESSING;
    /*
     * reserve CPR_MAXCONTIG virtual pages for cpr_dump()
     */
    CPR->c_mapping_area = i_cpr_map_setup();
    if (CPR->c_mapping_area == 0) {     /* no space in kernelmap */
        cpr_err(CE_CONT, "Unable to alloc from kernelmap.\n");
        mutex_exit(&cpr_slock);
        return (EAGAIN);
    }
    if (cpr_debug & CPR_DEBUG3)
        cpr_err(CE_CONT, "Reserved virtual range from 0x%p for writing "
            "kas\n", (void *)CPR->c_mapping_area);

    return (0);
}

/*
 * This routine releases any resources used during the checkpoint.
 */
void
cpr_done(void)
{
    cpr_stat_cleanup();
    i_cpr_bitmap_cleanup();

    /*
     * Free pages used by cpr buffers.
     */
    if (cpr_buf) {
        kmem_free(cpr_buf, cpr_buf_size);
        cpr_buf = NULL;
    }
    if (cpr_pagedata) {
        kmem_free(cpr_pagedata, cpr_pagedata_size);
        cpr_pagedata = NULL;
    }

    i_cpr_free_memory_resources();
    mutex_exit(&cpr_slock);
    cpr_err(CE_CONT, "System has been resumed.\n");
}


/*
 * reads config data into cprconfig
 */
static int
cpr_get_config(void)
{
    static char config_path[] = CPR_CONFIG;
    struct cprconfig *cf = &cprconfig;
    struct vnode *vp;
    char *fmt;
    int err;

    if (cprconfig_loaded)
        return (0);

    fmt = "cannot %s config file \"%s\", error %d\n";
    if (err = vn_open(config_path, UIO_SYSSPACE, FREAD, 0, &vp, 0, 0)) {
        cpr_err(CE_CONT, fmt, "open", config_path, err);
        return (err);
    }

    err = cpr_rdwr(UIO_READ, vp, cf, sizeof (*cf));
    (void) VOP_CLOSE(vp, FREAD, 1, (offset_t)0, CRED());
    VN_RELE(vp);
    if (err) {
        cpr_err(CE_CONT, fmt, "read", config_path, err);
        return (err);
    }

    if (cf->cf_magic == CPR_CONFIG_MAGIC)
        cprconfig_loaded = 1;
    else {
        cpr_err(CE_CONT, "invalid config file \"%s\", "
            "rerun pmconfig(1M)\n", config_path);
        err = EINVAL;
    }

    return (err);
}


/*
 * concat fs and path fields of the cprconfig structure;
 * returns pointer to the base of static data
 */
static char *
cpr_cprconfig_to_path(void)
{
    static char full_path[MAXNAMELEN];
    struct cprconfig *cf = &cprconfig;
    char *ptr;

    /*
     * build /fs/path without extra '/'
     */
    (void) strcpy(full_path, cf->cf_fs);
    if (strcmp(cf->cf_fs, "/"))
        (void) strcat(full_path, "/");
    ptr = cf->cf_path;
    if (*ptr == '/')
        ptr++;
    (void) strcat(full_path, ptr);
    return (full_path);
}


/*
 * Verify that the information in the configuration file regarding the
 * location for the statefile is still valid, depending on cf_type.
 * for CFT_UFS, cf_fs must still be a mounted filesystem, it must be
 *  mounted on the same device as when pmconfig was last run,
 *  and the translation of that device to a node in the prom's
 *  device tree must be the same as when pmconfig was last run.
 * for CFT_SPEC, cf_path must be the path to a block special file,
 *  it must have no file system mounted on it,
 *  and the translation of that device to a node in the prom's
 *  device tree must be the same as when pmconfig was last run.
 */
static int
cpr_verify_statefile_path(void)
{
    struct cprconfig *cf = &cprconfig;
    static const char long_name[] = "Statefile pathname is too long.\n";
    static const char lookup_fmt[] = "Lookup failed for "
        "cpr statefile device %s.\n";
    static const char path_chg_fmt[] = "Device path for statefile "
        "has changed from %s to %s.\t%s\n";
    static const char rerun[] = "Please rerun pmconfig(1m).";
    struct vfs *vfsp = NULL, *vfsp_save = rootvfs;
    ufsvfs_t *ufsvfsp = (ufsvfs_t *)rootvfs->vfs_data;
    ufsvfs_t *ufsvfsp_save = ufsvfsp;
    int error;
    struct vnode *vp;
    char *slash, *tail, *longest;
    char *errstr;
    int found = 0;
    union {
        char un_devpath[OBP_MAXPATHLEN];
        char un_sfpath[MAXNAMELEN];
    } un;
#define devpath un.un_devpath
#define sfpath  un.un_sfpath

    ASSERT(cprconfig_loaded);
    /*
     * We need not worry about locking or the timing of releasing
     * the vnode, since we are single-threaded now.
     */

    switch (cf->cf_type) {
    case CFT_SPEC:
        if (strlen(cf->cf_path) > sizeof (sfpath)) {
            cpr_err(CE_CONT, long_name);
            return (ENAMETOOLONG);
        }
        if ((error = lookupname(cf->cf_devfs,
            UIO_SYSSPACE, FOLLOW, NULLVPP, &vp)) != 0) {
            cpr_err(CE_CONT, lookup_fmt, cf->cf_devfs);
            return (error);
        }
        if (vp->v_type != VBLK)
            errstr = "statefile must be a block device";
        else if (vfs_devismounted(vp->v_rdev))
            errstr = "statefile device must not "
                "have a file system mounted on it";
        else if (IS_SWAPVP(vp))
            errstr = "statefile device must not "
                "be configured as swap file";
        else
            errstr = NULL;

        VN_RELE(vp);
        if (errstr) {
            cpr_err(CE_CONT, "%s.\n", errstr);
            return (ENOTSUP);
        }

        error = i_devname_to_promname(cf->cf_devfs, devpath,
            OBP_MAXPATHLEN);
        if (error || strcmp(devpath, cf->cf_dev_prom)) {
            cpr_err(CE_CONT, path_chg_fmt,
                cf->cf_dev_prom, devpath, rerun);
        }
        return (error);
    case CFT_UFS:
        break;      /* don't indent all the original code */
    default:
        cpr_err(CE_PANIC, "invalid cf_type");
    }

    /*
     * The original code for UFS statefile
     */
    if (strlen(cf->cf_fs) + strlen(cf->cf_path) + 2 > sizeof (sfpath)) {
        cpr_err(CE_CONT, long_name);
        return (ENAMETOOLONG);
    }

    bzero(sfpath, sizeof (sfpath));
    (void) strcpy(sfpath, cpr_cprconfig_to_path());

    if (*sfpath != '/') {
        cpr_err(CE_CONT, "Statefile pathname %s "
            "must begin with a /\n", sfpath);
        return (EINVAL);
    }

    /*
     * Find the longest prefix of the statefile pathname which
     * is the mountpoint of a filesystem.  This string must
     * match the cf_fs field we read from the config file.  Other-
     * wise the user has changed things without running pmconfig.
     */
    tail = longest = sfpath + 1;    /* pt beyond the leading "/" */
    while ((slash = strchr(tail, '/')) != NULL) {
        *slash = '\0';    /* temporarily terminate the string */
        if ((error = lookupname(sfpath,
            UIO_SYSSPACE, FOLLOW, NULLVPP, &vp)) != 0) {
            *slash = '/';
            cpr_err(CE_CONT, "A directory in the "
                "statefile path %s was not found.\n", sfpath);
            VN_RELE(vp);

            return (error);
        }

        vfs_list_read_lock();
        vfsp = rootvfs;
        do {
            ufsvfsp = (struct ufsvfs *)vfsp->vfs_data;
            if (ufsvfsp != NULL && ufsvfsp->vfs_root == vp) {
                found = 1;
                break;
            }
            vfsp = vfsp->vfs_next;
        } while (vfsp != rootvfs);
        vfs_list_unlock();

        /*
         * If we have found a filesystem mounted on the current
         * path prefix, remember the end of the string in
         * "longest".  If it happens to be the the exact fs
         * saved in the configuration file, save the current
         * ufsvfsp so we can make additional checks further down.
         */
        if (found) {
            longest = slash;
            if (strcmp(cf->cf_fs, sfpath) == 0) {
                ufsvfsp_save = ufsvfsp;
                vfsp_save = vfsp;
            }
            found = 0;
        }

        VN_RELE(vp);
        *slash = '/';
        tail = slash + 1;
    }
    *longest = '\0';
    if (cpr_is_ufs(vfsp_save) == 0 || strcmp(cf->cf_fs, sfpath)) {
        cpr_err(CE_CONT, "Filesystem containing "
            "the statefile when pmconfig was run (%s) has "
            "changed to %s. %s\n", cf->cf_fs, sfpath, rerun);
        return (EINVAL);
    }

    if ((error = lookupname(cf->cf_devfs,
        UIO_SYSSPACE, FOLLOW, NULLVPP, &vp)) != 0) {
        cpr_err(CE_CONT, lookup_fmt, cf->cf_devfs);
        return (error);
    }

    if (ufsvfsp_save->vfs_devvp->v_rdev != vp->v_rdev) {
        cpr_err(CE_CONT, "Filesystem containing "
            "statefile no longer mounted on device %s. "
            "See power.conf(4).", cf->cf_devfs);
        VN_RELE(vp);
        return (ENXIO);
    }
    VN_RELE(vp);

    error = i_devname_to_promname(cf->cf_devfs, devpath, OBP_MAXPATHLEN);
    if (error || strcmp(devpath, cf->cf_dev_prom)) {
        cpr_err(CE_CONT, path_chg_fmt,
            cf->cf_dev_prom, devpath, rerun);
        return (error);
    }

    return (0);
}

/*
 * Make sure that the statefile can be used as a block special statefile
 * (meaning that is exists and has nothing mounted on it)
 * Returns errno if not a valid statefile.
 */
int
cpr_check_spec_statefile(void)
{
    int err;

    if (err = cpr_get_config())
        return (err);
    ASSERT(cprconfig.cf_type == CFT_SPEC);

    if (cprconfig.cf_devfs == NULL)
        return (ENXIO);

    return (cpr_verify_statefile_path());

}

int
cpr_alloc_statefile(int alloc_retry)
{
    register int rc = 0;
    char *str;

    /*
     * Statefile size validation. If checkpoint the first time, disk blocks
     * allocation will be done; otherwise, just do file size check.
     * if statefile allocation is being retried, C_VP will be inited
     */
    if (alloc_retry) {
        str = "\n-->Retrying statefile allocation...";
        if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG7))
            prom_printf(str);
        if (C_VP->v_type != VBLK)
            (void) VOP_DUMPCTL(C_VP, DUMP_FREE, NULL);
    } else {
        /*
         * Open an exiting file for writing, the state file needs to be
         * pre-allocated since we can't and don't want to do allocation
         * during checkpoint (too much of the OS is disabled).
         *    - do a preliminary size checking here, if it is too small,
         *  allocate more space internally and retry.
         *    - check the vp to make sure it's the right type.
         */
        char *path = cpr_build_statefile_path();

        if (path == NULL)
            return (ENXIO);
        else if (rc = cpr_verify_statefile_path())
            return (rc);

        if (rc = vn_open(path, UIO_SYSSPACE,
            FCREAT|FWRITE, 0600, &C_VP, CRCREAT, 0)) {
            cpr_err(CE_WARN, "cannot open statefile %s", path);
            return (rc);
        }
    }

    /*
     * Only ufs and block special statefiles supported
     */
    if (C_VP->v_type != VREG && C_VP->v_type != VBLK) {
        cpr_err(CE_CONT,
            "Statefile must be regular file or block special file.");
        return (EACCES);
    }

    if (rc = cpr_statefile_ok(C_VP, alloc_retry))
        return (rc);

    if (C_VP->v_type != VBLK) {
        /*
         * sync out the fs change due to the statefile reservation.
         */
        (void) VFS_SYNC(C_VP->v_vfsp, 0, CRED());

        /*
         * Validate disk blocks allocation for the state file.
         * Ask the file system prepare itself for the dump operation.
         */
        if (rc = VOP_DUMPCTL(C_VP, DUMP_ALLOC, NULL)) {
            cpr_err(CE_CONT, "Error allocating "
                "blocks for cpr statefile.");
            return (rc);
        }
    }
    return (0);
}


/*
 * lookup device size in blocks,
 * and return available space in bytes
 */
size_t
cpr_get_devsize(dev_t dev)
{
    size_t bytes = 0;
    int64_t Nblocks;
    int nblocks;

    if ((Nblocks = bdev_Size(dev)) != -1)
        bytes = dbtob(Nblocks);
    else if ((nblocks = bdev_size(dev)) != -1)
        bytes = dbtob(nblocks);

    if (bytes > CPR_SPEC_OFFSET)
        bytes -= CPR_SPEC_OFFSET;
    else
        bytes = 0;

    return (bytes);
}


/*
 * increase statefile size
 */
static int
cpr_grow_statefile(vnode_t *vp, u_longlong_t newsize)
{
    extern uchar_t cpr_pagecopy[];
    struct inode *ip = VTOI(vp);
    u_longlong_t offset;
    int error, increase;
    ssize_t resid;

    rw_enter(&ip->i_contents, RW_READER);
    increase = (ip->i_size < newsize);
    offset = ip->i_size;
    rw_exit(&ip->i_contents);

    if (increase == 0)
        return (0);

    /*
     * write to each logical block to reserve disk space
     */
    error = 0;
    cpr_pagecopy[0] = '1';
    for (; offset < newsize; offset += ip->i_fs->fs_bsize) {
        if (error = vn_rdwr(UIO_WRITE, vp, (caddr_t)cpr_pagecopy,
            ip->i_fs->fs_bsize, (offset_t)offset, UIO_SYSSPACE, 0,
            (rlim64_t)MAXOFF_T, CRED(), &resid)) {
            if (error == ENOSPC) {
                cpr_err(CE_WARN, "error %d while reserving "
                    "disk space for statefile %s\n"
                    "wanted %lld bytes, file is %lld short",
                    error, cpr_cprconfig_to_path(),
                    newsize, newsize - offset);
            }
            break;
        }
    }
    return (error);
}


/*
 * do a simple estimate of the space needed to hold the statefile
 * taking compression into account, but be fairly conservative
 * so we have a better chance of completing; when dump fails,
 * the retry cost is fairly high.
 *
 * Do disk blocks allocation for the state file if no space has
 * been allocated yet. Since the state file will not be removed,
 * allocation should only be done once.
 */
static int
cpr_statefile_ok(vnode_t *vp, int alloc_retry)
{
    extern size_t cpr_bitmap_size;
    struct inode *ip = VTOI(vp);
    const int UCOMP_RATE = 20; /* comp. ratio*10 for user pages */
    u_longlong_t size, isize, ksize, raw_data;
    char *str, *est_fmt;
    size_t space;
    int error;

    /*
     * number of pages short for swapping.
     */
    STAT->cs_nosw_pages = k_anoninfo.ani_mem_resv;
    if (STAT->cs_nosw_pages < 0)
        STAT->cs_nosw_pages = 0;

    str = "cpr_statefile_ok:";

    CPR_DEBUG(CPR_DEBUG9, "Phys swap: max=%lu resv=%lu\n",
        k_anoninfo.ani_max, k_anoninfo.ani_phys_resv);
    CPR_DEBUG(CPR_DEBUG9, "Mem swap: max=%ld resv=%lu\n",
        MAX(availrmem - swapfs_minfree, 0),
        k_anoninfo.ani_mem_resv);
    CPR_DEBUG(CPR_DEBUG9, "Total available swap: %ld\n",
        CURRENT_TOTAL_AVAILABLE_SWAP);

    /*
     * try increasing filesize by 15%
     */
    if (alloc_retry) {
        /*
         * block device doesn't get any bigger
         */
        if (vp->v_type == VBLK) {
            if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6))
                prom_printf(
                    "Retry statefile on special file\n");
            return (ENOMEM);
        } else {
            rw_enter(&ip->i_contents, RW_READER);
            size = (ip->i_size * SIZE_RATE) / INTEGRAL;
            rw_exit(&ip->i_contents);
        }
        if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6))
            prom_printf("Retry statefile size = %lld\n", size);
    } else {
        u_longlong_t cpd_size;
        pgcnt_t npages, nback;
        int ndvram;

        ndvram = 0;
        (void) callb_execute_class(CB_CL_CPR_FB,
            (int)(uintptr_t)&ndvram);
        if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6))
            prom_printf("ndvram size = %d\n", ndvram);

        /*
         * estimate 1 cpd_t for every (CPR_MAXCONTIG / 2) pages
         */
        npages = cpr_count_kpages(REGULAR_BITMAP, cpr_nobit);
        cpd_size = sizeof (cpd_t) * (npages / (CPR_MAXCONTIG / 2));
        raw_data = cpd_size + cpr_bitmap_size;
        ksize = ndvram + mmu_ptob(npages);

        est_fmt = "%s estimated size with "
            "%scompression %lld, ksize %lld\n";
        nback = mmu_ptob(STAT->cs_nosw_pages);
        if (CPR->c_flags & C_COMPRESSING) {
            size = ((ksize * COMPRESS_PERCENT) / INTEGRAL) +
                raw_data + ((nback * 10) / UCOMP_RATE);
            CPR_DEBUG(CPR_DEBUG1, est_fmt, str, "", size, ksize);
        } else {
            size = ksize + raw_data + nback;
            CPR_DEBUG(CPR_DEBUG1, est_fmt, str, "no ",
                size, ksize);
        }
    }

    /*
     * All this is much simpler for a block device
     */
    if (vp->v_type == VBLK) {
        space = cpr_get_devsize(vp->v_rdev);
        if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6))
            prom_printf("statefile dev size %lu\n", space);

        /*
         * Export the estimated filesize info, this value will be
         * compared before dumping out the statefile in the case of
         * no compression.
         */
        STAT->cs_est_statefsz = size;
        if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6))
            prom_printf("%s Estimated statefile size %llu, "
                "space %lu\n", str, size, space);
        if (size > space) {
            cpr_err(CE_CONT, "Statefile partition too small.");
            return (ENOMEM);
        }
        return (0);
    } else {
        if (CPR->c_alloc_cnt++ > C_MAX_ALLOC_RETRY) {
            cpr_err(CE_CONT, "Statefile allocation retry failed\n");
            return (ENOMEM);
        }

        /*
         * Estimate space needed for the state file.
         *
         * State file size in bytes:
         *  kernel size + non-cache pte seg +
         *  bitmap size + cpr state file headers size
         * (round up to fs->fs_bsize)
         */
        size = blkroundup(ip->i_fs, size);

        /*
         * Export the estimated filesize info, this value will be
         * compared before dumping out the statefile in the case of
         * no compression.
         */
        STAT->cs_est_statefsz = size;
        error = cpr_grow_statefile(vp, size);
        if (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6)) {
            rw_enter(&ip->i_contents, RW_READER);
            isize = ip->i_size;
            rw_exit(&ip->i_contents);
            prom_printf("%s Estimated statefile size %lld, "
                "i_size %lld\n", str, size, isize);
        }

        return (error);
    }
}


void
cpr_statef_close(void)
{
    if (C_VP) {
        if (!cpr_reusable_mode)
            (void) VOP_DUMPCTL(C_VP, DUMP_FREE, NULL);
        (void) VOP_CLOSE(C_VP, FWRITE, 1, (offset_t)0, CRED());
        VN_RELE(C_VP);
        C_VP = 0;
    }
}


/*
 * open cpr default file and display error
 */
int
cpr_open_deffile(int mode, vnode_t **vpp)
{
    int error;

    if (error = cpr_open(cpr_default_path, mode, vpp))
        cpr_err(CE_CONT, "cannot open \"%s\", error %d\n",
            cpr_default_path, error);
    return (error);
}


/*
 * write cdef_t to disk.  This contains the original values of prom
 * properties that we modify.  We fill in the magic number of the file
 * here as a signal to the booter code that the state file is valid.
 * Be sure the file gets synced, since we may be shutting down the OS.
 */
int
cpr_write_deffile(cdef_t *cdef)
{
    struct vnode *vp;
    char *str;
    int rc;

    if (rc = cpr_open_deffile(FCREAT|FWRITE, &vp))
        return (rc);

    if (rc = cpr_rdwr(UIO_WRITE, vp, cdef, sizeof (*cdef)))
        str = "write";
    else if (rc = VOP_FSYNC(vp, FSYNC, CRED()))
        str = "fsync";
    (void) VOP_CLOSE(vp, FWRITE, 1, (offset_t)0, CRED());
    VN_RELE(vp);

    if (rc) {
        cpr_err(CE_WARN, "%s error %d, file \"%s\"",
            str, rc, cpr_default_path);
    }
    return (rc);
}

/*
 * Clear the magic number in the defaults file.  This tells the booter
 * program that the state file is not current and thus prevents
 * any attempt to restore from an obsolete state file.
 */
void
cpr_clear_definfo(void)
{
    struct vnode *vp;
    cmini_t mini;

    if ((CPR->c_cprboot_magic != CPR_DEFAULT_MAGIC) ||
        cpr_open_deffile(FCREAT|FWRITE, &vp))
        return;
    mini.magic = mini.reusable = 0;
    (void) cpr_rdwr(UIO_WRITE, vp, &mini, sizeof (mini));
    (void) VOP_CLOSE(vp, FWRITE, 1, (offset_t)0, CRED());
    VN_RELE(vp);
}

/*
 * If the cpr default file is invalid, then we must not be in reusable mode
 * if it is valid, it tells us our mode
 */
int
cpr_get_reusable_mode(void)
{
    struct vnode *vp;
    cmini_t mini;
    int rc;

    if (cpr_open(cpr_default_path, FREAD, &vp))
        return (0);

    rc = cpr_rdwr(UIO_READ, vp, &mini, sizeof (mini));
    (void) VOP_CLOSE(vp, FREAD, 1, (offset_t)0, CRED());
    VN_RELE(vp);
    if (rc == 0 && mini.magic == CPR_DEFAULT_MAGIC)
        return (mini.reusable);

    return (0);
}

/*
 * clock/time related routines
 */
static time_t   cpr_time_stamp;


void
cpr_tod_get(cpr_time_t *ctp)
{
    timestruc_t ts;

    mutex_enter(&tod_lock);
    ts = tod_get();
    mutex_exit(&tod_lock);
    ctp->tv_sec = (time32_t)ts.tv_sec;
    ctp->tv_nsec = (int32_t)ts.tv_nsec;
}

void
cpr_tod_fault_reset(void)
{
    mutex_enter(&tod_lock);
    tod_fault_reset();
    mutex_exit(&tod_lock);
}

void
cpr_save_time(void)
{
    cpr_time_stamp = gethrestime_sec();
}

/*
 * correct time based on saved time stamp or hardware clock
 */
void
cpr_restore_time(void)
{
    clkset(cpr_time_stamp);
}

/*
 * CPU ONLINE/OFFLINE CODE
 */
int
cpr_mp_offline(void)
{
    cpu_t *cp, *bootcpu;
    int rc = 0;
    int brought_up_boot = 0;

    /*
     * Do nothing for UP.
     */
    if (ncpus == 1)
        return (0);

    mutex_enter(&cpu_lock);

    cpr_save_mp_state();

    bootcpu = i_cpr_bootcpu();
    if (!CPU_ACTIVE(bootcpu)) {
        if ((rc = cpr_p_online(bootcpu, CPU_CPR_ONLINE))) {
            mutex_exit(&cpu_lock);
            return (rc);
        }
        brought_up_boot = 1;
    }

    cp = cpu_list;
    do {
        if (cp == bootcpu)
            continue;
        if (cp->cpu_flags & CPU_OFFLINE)
            continue;
        if ((rc = cpr_p_online(cp, CPU_CPR_OFFLINE))) {
            mutex_exit(&cpu_lock);
            return (rc);
        }
    } while ((cp = cp->cpu_next) != cpu_list);
    if (brought_up_boot && (cpr_debug & (CPR_DEBUG1 | CPR_DEBUG6)))
        prom_printf("changed cpu %p to state %d\n",
            bootcpu, CPU_CPR_ONLINE);
    mutex_exit(&cpu_lock);

    return (rc);
}

int
cpr_mp_online(void)
{
    cpu_t *cp, *bootcpu = CPU;
    int rc = 0;

    /*
     * Do nothing for UP.
     */
    if (ncpus == 1)
        return (0);

    /*
     * cpr_save_mp_state() sets CPU_CPR_ONLINE in cpu_cpr_flags
     * to indicate a cpu was online at the time of cpr_suspend();
     * now restart those cpus that were marked as CPU_CPR_ONLINE
     * and actually are offline.
     */
    mutex_enter(&cpu_lock);
    for (cp = bootcpu->cpu_next; cp != bootcpu; cp = cp->cpu_next) {
        /*
         * Clear the CPU_FROZEN flag in all cases.
         */
        cp->cpu_flags &= ~CPU_FROZEN;

        if (CPU_CPR_IS_OFFLINE(cp))
            continue;
        if (CPU_ACTIVE(cp))
            continue;
        if ((rc = cpr_p_online(cp, CPU_CPR_ONLINE))) {
            mutex_exit(&cpu_lock);
            return (rc);
        }
    }

    /*
     * turn off the boot cpu if it was offlined
     */
    if (CPU_CPR_IS_OFFLINE(bootcpu)) {
        if ((rc = cpr_p_online(bootcpu, CPU_CPR_OFFLINE))) {
            mutex_exit(&cpu_lock);
            return (rc);
        }
    }
    mutex_exit(&cpu_lock);
    return (0);
}

static void
cpr_save_mp_state(void)
{
    cpu_t *cp;

    ASSERT(MUTEX_HELD(&cpu_lock));

    cp = cpu_list;
    do {
        cp->cpu_cpr_flags &= ~CPU_CPR_ONLINE;
        if (CPU_ACTIVE(cp))
            CPU_SET_CPR_FLAGS(cp, CPU_CPR_ONLINE);
    } while ((cp = cp->cpu_next) != cpu_list);
}

/*
 * change cpu to online/offline
 */
static int
cpr_p_online(cpu_t *cp, int state)
{
    int rc;

    ASSERT(MUTEX_HELD(&cpu_lock));

    switch (state) {
    case CPU_CPR_ONLINE:
        rc = cpu_online(cp);
        break;
    case CPU_CPR_OFFLINE:
        rc = cpu_offline(cp, CPU_FORCED);
        break;
    }
    if (rc) {
        cpr_err(CE_WARN, "Failed to change processor %d to "
            "state %d, (errno %d)", cp->cpu_id, state, rc);
    }
    return (rc);
}

/*
 * Construct the pathname of the state file and return a pointer to
 * caller.  Read the config file to get the mount point of the
 * filesystem and the pathname within fs.
 */
char *
cpr_build_statefile_path(void)
{
    struct cprconfig *cf = &cprconfig;

    if (cpr_get_config())
        return (NULL);

    switch (cf->cf_type) {
    case CFT_UFS:
        if (strlen(cf->cf_path) + strlen(cf->cf_fs) >= MAXNAMELEN - 1) {
            cpr_err(CE_CONT, "Statefile path is too long.\n");
            return (NULL);
        }
        return (cpr_cprconfig_to_path());
    case CFT_SPEC:
        return (cf->cf_devfs);
    default:
        cpr_err(CE_PANIC, "invalid statefile type");
        /*NOTREACHED*/
        return (NULL);
    }
}

int
cpr_statefile_is_spec(void)
{
    if (cpr_get_config())
        return (0);
    return (cprconfig.cf_type == CFT_SPEC);
}

char *
cpr_get_statefile_prom_path(void)
{
    struct cprconfig *cf = &cprconfig;

    ASSERT(cprconfig_loaded);
    ASSERT(cf->cf_magic == CPR_CONFIG_MAGIC);
    ASSERT(cf->cf_type == CFT_SPEC);
    return (cf->cf_dev_prom);
}


/*
 * XXX The following routines need to be in the vfs source code.
 */

int
cpr_is_ufs(struct vfs *vfsp)
{
    char *fsname;

    fsname = vfssw[vfsp->vfs_fstype].vsw_name;
    return (strcmp(fsname, "ufs") == 0);
}

/*
 * This is a list of file systems that are allowed to be writeable when a
 * reusable statefile checkpoint is taken.  They must not have any state that
 * cannot be restored to consistency by simply rebooting using the checkpoint.
 * (In contrast to ufs, cachefs and pcfs which have disk state that could get
 * out of sync with the in-kernel data).
 */
int
cpr_reusable_mount_check(void)
{
    struct vfs *vfsp;
    char *fsname;
    char **cpp;
    static char *cpr_writeok_fss[] = {
        "autofs", "devfs", "fd", "lofs", "mntfs", "namefs", "nfs",
        "proc", "tmpfs", "ctfs", "objfs", "dev", NULL
    };

    vfs_list_read_lock();
    vfsp = rootvfs;
    do {
        if (vfsp->vfs_flag & VFS_RDONLY) {
            vfsp = vfsp->vfs_next;
            continue;
        }
        fsname = vfssw[vfsp->vfs_fstype].vsw_name;
        for (cpp = cpr_writeok_fss; *cpp; cpp++) {
            if (strcmp(fsname, *cpp) == 0)
                break;
        }
        /*
         * if the inner loop reached the NULL terminator,
         * the current fs-type does not match any OK-type
         */
        if (*cpp == NULL) {
            cpr_err(CE_CONT, "a filesystem of type %s is "
                "mounted read/write.\nReusable statefile requires "
                "no writeable filesystem of this type be mounted\n",
                fsname);
            vfs_list_unlock();
            return (EINVAL);
        }
        vfsp = vfsp->vfs_next;
    } while (vfsp != rootvfs);
    vfs_list_unlock();
    return (0);
}

/*
 * Force a fresh read of the cprinfo per uadmin 3 call
 */
void
cpr_forget_cprconfig(void)
{
    cprconfig_loaded = 0;
}


/*
 * return statefile offset in DEV_BSIZE units
 */
int
cpr_statefile_offset(void)
{
    return (cpr_statefile_is_spec() ? btod(CPR_SPEC_OFFSET) : 0);
}