coverity appeasement

[minix.git] / sys / ufs / lfs / lfs_vfsops.c

/*      $NetBSD: lfs_vfsops.c,v 1.291 2011/11/14 18:35:14 hannken Exp $ */

/*-
 * Copyright (c) 1999, 2000, 2001, 2002, 2003, 2007, 2007
 *     The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Konrad E. Schroder <perseant@hhhh.org>.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
/*-
 * Copyright (c) 1989, 1991, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)lfs_vfsops.c        8.20 (Berkeley) 6/10/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: lfs_vfsops.c,v 1.291 2011/11/14 18:35:14 hannken Exp $");

#if defined(_KERNEL_OPT)
#include "opt_lfs.h"
#include "opt_quota.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/kthread.h>
#include <sys/buf.h>
#include <sys/device.h>
#include <sys/mbuf.h>
#include <sys/file.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/pool.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <uvm/uvm_extern.h>
#include <sys/sysctl.h>
#include <sys/conf.h>
#include <sys/kauth.h>
#include <sys/module.h>
#include <sys/syscallvar.h>
#include <sys/syscall.h>
#include <sys/syscallargs.h>

#include <miscfs/specfs/specdev.h>

#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>

#include <uvm/uvm.h>
#include <uvm/uvm_stat.h>
#include <uvm/uvm_pager.h>
#include <uvm/uvm_pdaemon.h>

#include <ufs/lfs/lfs.h>
#include <ufs/lfs/lfs_extern.h>

#include <miscfs/genfs/genfs.h>
#include <miscfs/genfs/genfs_node.h>

MODULE(MODULE_CLASS_VFS, lfs, "ffs");

static int lfs_gop_write(struct vnode *, struct vm_page **, int, int);
static bool lfs_issequential_hole(const struct ufsmount *,
    daddr_t, daddr_t);

static int lfs_mountfs(struct vnode *, struct mount *, struct lwp *);

static struct sysctllog *lfs_sysctl_log;

extern const struct vnodeopv_desc lfs_vnodeop_opv_desc;
extern const struct vnodeopv_desc lfs_specop_opv_desc;
extern const struct vnodeopv_desc lfs_fifoop_opv_desc;

pid_t lfs_writer_daemon = 0;
int lfs_do_flush = 0;
#ifdef LFS_KERNEL_RFW
int lfs_do_rfw = 0;
#endif

const struct vnodeopv_desc * const lfs_vnodeopv_descs[] = {
        &lfs_vnodeop_opv_desc,
        &lfs_specop_opv_desc,
        &lfs_fifoop_opv_desc,
        NULL,
};

struct vfsops lfs_vfsops = {
        MOUNT_LFS,
        sizeof (struct ufs_args),
        lfs_mount,
        ufs_start,
        lfs_unmount,
        ufs_root,
        ufs_quotactl,
        lfs_statvfs,
        lfs_sync,
        lfs_vget,
        lfs_fhtovp,
        lfs_vptofh,
        lfs_init,
        lfs_reinit,
        lfs_done,
        lfs_mountroot,
        (int (*)(struct mount *, struct vnode *, struct timespec *)) eopnotsupp,
        vfs_stdextattrctl,
        (void *)eopnotsupp,     /* vfs_suspendctl */
        genfs_renamelock_enter,
        genfs_renamelock_exit,
        (void *)eopnotsupp,
        lfs_vnodeopv_descs,
        0,
        { NULL, NULL },
};

const struct genfs_ops lfs_genfsops = {
        .gop_size = lfs_gop_size,
        .gop_alloc = ufs_gop_alloc,
        .gop_write = lfs_gop_write,
        .gop_markupdate = ufs_gop_markupdate,
};

static const struct ufs_ops lfs_ufsops = {
        .uo_itimes = NULL,
        .uo_update = lfs_update,
        .uo_truncate = lfs_truncate,
        .uo_valloc = lfs_valloc,
        .uo_vfree = lfs_vfree,
        .uo_balloc = lfs_balloc,
        .uo_unmark_vnode = lfs_unmark_vnode,
};

struct shortlong {
        const char *sname;
        const char *lname;
};

static int
sysctl_lfs_dostats(SYSCTLFN_ARGS)
{
        extern struct lfs_stats lfs_stats;
        extern int lfs_dostats;
        int error;

        error = sysctl_lookup(SYSCTLFN_CALL(rnode));
        if (error || newp == NULL)
                return (error);

        if (lfs_dostats == 0)
                memset(&lfs_stats, 0, sizeof(lfs_stats));

        return (0);
}

static void
lfs_sysctl_setup(struct sysctllog **clog)
{
        int i;
        extern int lfs_writeindir, lfs_dostats, lfs_clean_vnhead,
                   lfs_fs_pagetrip, lfs_ignore_lazy_sync;
#ifdef DEBUG
        extern int lfs_debug_log_subsys[DLOG_MAX];
        struct shortlong dlog_names[DLOG_MAX] = { /* Must match lfs.h ! */
                { "rollforward", "Debug roll-forward code" },
                { "alloc",      "Debug inode allocation and free list" },
                { "avail",      "Debug space-available-now accounting" },
                { "flush",      "Debug flush triggers" },
                { "lockedlist", "Debug locked list accounting" },
                { "vnode_verbose", "Verbose per-vnode-written debugging" },
                { "vnode",      "Debug vnode use during segment write" },
                { "segment",    "Debug segment writing" },
                { "seguse",     "Debug segment used-bytes accounting" },
                { "cleaner",    "Debug cleaning routines" },
                { "mount",      "Debug mount/unmount routines" },
                { "pagecache",  "Debug UBC interactions" },
                { "dirop",      "Debug directory-operation accounting" },
                { "malloc",     "Debug private malloc accounting" },
        };
#endif /* DEBUG */
        struct shortlong stat_names[] = { /* Must match lfs.h! */
                { "segsused",       "Number of new segments allocated" },
                { "psegwrites",     "Number of partial-segment writes" },
                { "psyncwrites",    "Number of synchronous partial-segment"
                                    " writes" },
                { "pcleanwrites",   "Number of partial-segment writes by the"
                                    " cleaner" },
                { "blocktot",       "Number of blocks written" },
                { "cleanblocks",    "Number of blocks written by the cleaner" },
                { "ncheckpoints",   "Number of checkpoints made" },
                { "nwrites",        "Number of whole writes" },
                { "nsync_writes",   "Number of synchronous writes" },
                { "wait_exceeded",  "Number of times writer waited for"
                                    " cleaner" },
                { "write_exceeded", "Number of times writer invoked flush" },
                { "flush_invoked",  "Number of times flush was invoked" },
                { "vflush_invoked", "Number of time vflush was called" },
                { "clean_inlocked", "Number of vnodes skipped for VI_XLOCK" },
                { "clean_vnlocked", "Number of vnodes skipped for vget failure" },
                { "segs_reclaimed", "Number of segments reclaimed" },
        };

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "vfs", NULL,
                       NULL, 0, NULL, 0,
                       CTL_VFS, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "lfs",
                       SYSCTL_DESCR("Log-structured file system"),
                       NULL, 0, NULL, 0,
                       CTL_VFS, 5, CTL_EOL);
        /*
         * XXX the "5" above could be dynamic, thereby eliminating one
         * more instance of the "number to vfs" mapping problem, but
         * "5" is the order as taken from sys/mount.h
         */

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "flushindir", NULL,
                       NULL, 0, &lfs_writeindir, 0,
                       CTL_VFS, 5, LFS_WRITEINDIR, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "clean_vnhead", NULL,
                       NULL, 0, &lfs_clean_vnhead, 0,
                       CTL_VFS, 5, LFS_CLEAN_VNHEAD, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "dostats",
                       SYSCTL_DESCR("Maintain statistics on LFS operations"),
                       sysctl_lfs_dostats, 0, &lfs_dostats, 0,
                       CTL_VFS, 5, LFS_DOSTATS, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "pagetrip",
                       SYSCTL_DESCR("How many dirty pages in fs triggers"
                                    " a flush"),
                       NULL, 0, &lfs_fs_pagetrip, 0,
                       CTL_VFS, 5, LFS_FS_PAGETRIP, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "ignore_lazy_sync",
                       SYSCTL_DESCR("Lazy Sync is ignored entirely"),
                       NULL, 0, &lfs_ignore_lazy_sync, 0,
                       CTL_VFS, 5, LFS_IGNORE_LAZY_SYNC, CTL_EOL);
#ifdef LFS_KERNEL_RFW
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                       CTLTYPE_INT, "rfw",
                       SYSCTL_DESCR("Use in-kernel roll-forward on mount"),
                       NULL, 0, &lfs_do_rfw, 0,
                       CTL_VFS, 5, LFS_DO_RFW, CTL_EOL);
#endif

        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "stats",
                       SYSCTL_DESCR("Debugging options"),
                       NULL, 0, NULL, 0,
                       CTL_VFS, 5, LFS_STATS, CTL_EOL);
        for (i = 0; i < sizeof(struct lfs_stats) / sizeof(u_int); i++) {
                sysctl_createv(clog, 0, NULL, NULL,
                               CTLFLAG_PERMANENT|CTLFLAG_READONLY,
                               CTLTYPE_INT, stat_names[i].sname,
                               SYSCTL_DESCR(stat_names[i].lname),
                               NULL, 0, &(((u_int *)&lfs_stats.segsused)[i]),
                               0, CTL_VFS, 5, LFS_STATS, i, CTL_EOL);
        }

#ifdef DEBUG
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT,
                       CTLTYPE_NODE, "debug",
                       SYSCTL_DESCR("Debugging options"),
                       NULL, 0, NULL, 0,
                       CTL_VFS, 5, LFS_DEBUGLOG, CTL_EOL);
        for (i = 0; i < DLOG_MAX; i++) {
                sysctl_createv(clog, 0, NULL, NULL,
                               CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
                               CTLTYPE_INT, dlog_names[i].sname,
                               SYSCTL_DESCR(dlog_names[i].lname),
                               NULL, 0, &(lfs_debug_log_subsys[i]), 0,
                               CTL_VFS, 5, LFS_DEBUGLOG, i, CTL_EOL);
        }
#endif
}

/* old cleaner syscall interface.  see VOP_FCNTL() */
static const struct syscall_package lfs_syscalls[] = {
        { SYS_lfs_bmapv,        0, (sy_call_t *)sys_lfs_bmapv           },
        { SYS_lfs_markv,        0, (sy_call_t *)sys_lfs_markv           },
        { SYS_lfs_segclean,     0, (sy_call_t *)sys___lfs_segwait50     },
        { 0, 0, NULL },
};

static int
lfs_modcmd(modcmd_t cmd, void *arg)
{
        int error;

        switch (cmd) {
        case MODULE_CMD_INIT:
                error = syscall_establish(NULL, lfs_syscalls);
                if (error)
                        return error;
                error = vfs_attach(&lfs_vfsops);
                if (error != 0) {
                        syscall_disestablish(NULL, lfs_syscalls);
                        break;
                }
                lfs_sysctl_setup(&lfs_sysctl_log);
                break;
        case MODULE_CMD_FINI:
                error = vfs_detach(&lfs_vfsops);
                if (error != 0)
                        break;
                syscall_disestablish(NULL, lfs_syscalls);
                sysctl_teardown(&lfs_sysctl_log);
                break;
        default:
                error = ENOTTY;
                break;
        }

        return (error);
}

/*
 * XXX Same structure as FFS inodes?  Should we share a common pool?
 */
struct pool lfs_inode_pool;
struct pool lfs_dinode_pool;
struct pool lfs_inoext_pool;
struct pool lfs_lbnentry_pool;

/*
 * The writer daemon.  UVM keeps track of how many dirty pages we are holding
 * in lfs_subsys_pages; the daemon flushes the filesystem when this value
 * crosses the (user-defined) threshhold LFS_MAX_PAGES.
 */
static void
lfs_writerd(void *arg)
{
        struct mount *mp, *nmp;
        struct lfs *fs;
        int fsflags;
        int loopcount;

        lfs_writer_daemon = curproc->p_pid;

        mutex_enter(&lfs_lock);
        for (;;) {
                mtsleep(&lfs_writer_daemon, PVM | PNORELOCK, "lfswriter", hz/10,
                    &lfs_lock);

                /*
                 * Look through the list of LFSs to see if any of them
                 * have requested pageouts.
                 */
                mutex_enter(&mountlist_lock);
                for (mp = CIRCLEQ_FIRST(&mountlist); mp != (void *)&mountlist;
                     mp = nmp) {
                        if (vfs_busy(mp, &nmp)) {
                                continue;
                        }
                        if (strncmp(mp->mnt_stat.f_fstypename, MOUNT_LFS,
                            sizeof(mp->mnt_stat.f_fstypename)) == 0) {
                                fs = VFSTOUFS(mp)->um_lfs;
                                mutex_enter(&lfs_lock);
                                fsflags = 0;
                                if ((fs->lfs_dirvcount > LFS_MAX_FSDIROP(fs) ||
                                     lfs_dirvcount > LFS_MAX_DIROP) &&
                                    fs->lfs_dirops == 0)
                                        fsflags |= SEGM_CKP;
                                if (fs->lfs_pdflush) {
                                        DLOG((DLOG_FLUSH, "lfs_writerd: pdflush set\n"));
                                        fs->lfs_pdflush = 0;
                                        lfs_flush_fs(fs, fsflags);
                                        mutex_exit(&lfs_lock);
                                } else if (!TAILQ_EMPTY(&fs->lfs_pchainhd)) {
                                        DLOG((DLOG_FLUSH, "lfs_writerd: pchain non-empty\n"));
                                        mutex_exit(&lfs_lock);
                                        lfs_writer_enter(fs, "wrdirop");
                                        lfs_flush_pchain(fs);
                                        lfs_writer_leave(fs);
                                } else
                                        mutex_exit(&lfs_lock);
                        }
                        vfs_unbusy(mp, false, &nmp);
                }
                mutex_exit(&mountlist_lock);

                /*
                 * If global state wants a flush, flush everything.
                 */
                mutex_enter(&lfs_lock);
                loopcount = 0;
                if (lfs_do_flush || locked_queue_count > LFS_MAX_BUFS ||
                        locked_queue_bytes > LFS_MAX_BYTES ||
                        lfs_subsys_pages > LFS_MAX_PAGES) {

                        if (lfs_do_flush) {
                                DLOG((DLOG_FLUSH, "daemon: lfs_do_flush\n"));
                        }
                        if (locked_queue_count > LFS_MAX_BUFS) {
                                DLOG((DLOG_FLUSH, "daemon: lqc = %d, max %d\n",
                                      locked_queue_count, LFS_MAX_BUFS));
                        }
                        if (locked_queue_bytes > LFS_MAX_BYTES) {
                                DLOG((DLOG_FLUSH, "daemon: lqb = %ld, max %ld\n",
                                      locked_queue_bytes, LFS_MAX_BYTES));
                        }
                        if (lfs_subsys_pages > LFS_MAX_PAGES) {
                                DLOG((DLOG_FLUSH, "daemon: lssp = %d, max %d\n",
                                      lfs_subsys_pages, LFS_MAX_PAGES));
                        }

                        lfs_flush(NULL, SEGM_WRITERD, 0);
                        lfs_do_flush = 0;
                }
        }
        /* NOTREACHED */
}

/*
 * Initialize the filesystem, most work done by ufs_init.
 */
void
lfs_init(void)
{

        malloc_type_attach(M_SEGMENT);
        pool_init(&lfs_inode_pool, sizeof(struct inode), 0, 0, 0,
            "lfsinopl", &pool_allocator_nointr, IPL_NONE);
        pool_init(&lfs_dinode_pool, sizeof(struct ufs1_dinode), 0, 0, 0,
            "lfsdinopl", &pool_allocator_nointr, IPL_NONE);
        pool_init(&lfs_inoext_pool, sizeof(struct lfs_inode_ext), 8, 0, 0,
            "lfsinoextpl", &pool_allocator_nointr, IPL_NONE);
        pool_init(&lfs_lbnentry_pool, sizeof(struct lbnentry), 0, 0, 0,
            "lfslbnpool", &pool_allocator_nointr, IPL_NONE);
        ufs_init();

#ifdef DEBUG
        memset(lfs_log, 0, sizeof(lfs_log));
#endif
        mutex_init(&lfs_lock, MUTEX_DEFAULT, IPL_NONE);
        cv_init(&locked_queue_cv, "lfsbuf");
        cv_init(&lfs_writing_cv, "lfsflush");
}

void
lfs_reinit(void)
{
        ufs_reinit();
}

void
lfs_done(void)
{
        ufs_done();
        mutex_destroy(&lfs_lock);
        cv_destroy(&locked_queue_cv);
        cv_destroy(&lfs_writing_cv);
        pool_destroy(&lfs_inode_pool);
        pool_destroy(&lfs_dinode_pool);
        pool_destroy(&lfs_inoext_pool);
        pool_destroy(&lfs_lbnentry_pool);
        malloc_type_detach(M_SEGMENT);
}

/*
 * Called by main() when ufs is going to be mounted as root.
 */
int
lfs_mountroot(void)
{
        extern struct vnode *rootvp;
        struct lfs *fs = NULL;                          /* LFS */
        struct mount *mp;
        struct lwp *l = curlwp;
        struct ufsmount *ump;
        int error;

        if (device_class(root_device) != DV_DISK)
                return (ENODEV);

        if (rootdev == NODEV)
                return (ENODEV);
        if ((error = vfs_rootmountalloc(MOUNT_LFS, "root_device", &mp))) {
                vrele(rootvp);
                return (error);
        }
        if ((error = lfs_mountfs(rootvp, mp, l))) {
                vfs_unbusy(mp, false, NULL);
                vfs_destroy(mp);
                return (error);
        }
        mutex_enter(&mountlist_lock);
        CIRCLEQ_INSERT_TAIL(&mountlist, mp, mnt_list);
        mutex_exit(&mountlist_lock);
        ump = VFSTOUFS(mp);
        fs = ump->um_lfs;
        memset(fs->lfs_fsmnt, 0, sizeof(fs->lfs_fsmnt));
        (void)copystr(mp->mnt_stat.f_mntonname, fs->lfs_fsmnt, MNAMELEN - 1, 0);
        (void)lfs_statvfs(mp, &mp->mnt_stat);
        vfs_unbusy(mp, false, NULL);
        setrootfstime((time_t)(VFSTOUFS(mp)->um_lfs->lfs_tstamp));
        return (0);
}

/*
 * VFS Operations.
 *
 * mount system call
 */
int
lfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
{
        struct lwp *l = curlwp;
        struct vnode *devvp;
        struct ufs_args *args = data;
        struct ufsmount *ump = NULL;
        struct lfs *fs = NULL;                          /* LFS */
        int error = 0, update;
        mode_t accessmode;

        if (*data_len < sizeof *args)
                return EINVAL;

        if (mp->mnt_flag & MNT_GETARGS) {
                ump = VFSTOUFS(mp);
                if (ump == NULL)
                        return EIO;
                args->fspec = NULL;
                *data_len = sizeof *args;
                return 0;
        }

        update = mp->mnt_flag & MNT_UPDATE;

        /* Check arguments */
        if (args->fspec != NULL) {
                /*
                 * Look up the name and verify that it's sane.
                 */
                error = namei_simple_user(args->fspec,
                                        NSM_FOLLOW_NOEMULROOT, &devvp);
                if (error != 0)
                        return (error);

                if (!update) {
                        /*
                         * Be sure this is a valid block device
                         */
                        if (devvp->v_type != VBLK)
                                error = ENOTBLK;
                        else if (bdevsw_lookup(devvp->v_rdev) == NULL)
                                error = ENXIO;
                } else {
                        /*
                         * Be sure we're still naming the same device
                         * used for our initial mount
                         */
                        ump = VFSTOUFS(mp);
                        if (devvp != ump->um_devvp) {
                                if (devvp->v_rdev != ump->um_devvp->v_rdev)
                                        error = EINVAL;
                                else {
                                        vrele(devvp);
                                        devvp = ump->um_devvp;
                                        vref(devvp);
                                }
                        }
                }
        } else {
                if (!update) {
                        /* New mounts must have a filename for the device */
                        return (EINVAL);
                } else {
                        /* Use the extant mount */
                        ump = VFSTOUFS(mp);
                        devvp = ump->um_devvp;
                        vref(devvp);
                }
        }


        /*
         * If mount by non-root, then verify that user has necessary
         * permissions on the device.
         */
        if (error == 0) {
                accessmode = VREAD;
                if (update ?
                    (mp->mnt_iflag & IMNT_WANTRDWR) != 0 :
                    (mp->mnt_flag & MNT_RDONLY) == 0)
                        accessmode |= VWRITE;
                vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
                error = genfs_can_mount(devvp, accessmode, l->l_cred);
                VOP_UNLOCK(devvp);
        }

        if (error) {
                vrele(devvp);
                return (error);
        }

        if (!update) {
                int flags;

                if (mp->mnt_flag & MNT_RDONLY)
                        flags = FREAD;
                else
                        flags = FREAD|FWRITE;
                vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
                error = VOP_OPEN(devvp, flags, FSCRED);
                VOP_UNLOCK(devvp);
                if (error)
                        goto fail;
                error = lfs_mountfs(devvp, mp, l);              /* LFS */
                if (error) {
                        vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
                        (void)VOP_CLOSE(devvp, flags, NOCRED);
                        VOP_UNLOCK(devvp);
                        goto fail;
                }

                ump = VFSTOUFS(mp);
                fs = ump->um_lfs;
        } else {
                /*
                 * Update the mount.
                 */

                /*
                 * The initial mount got a reference on this
                 * device, so drop the one obtained via
                 * namei(), above.
                 */
                vrele(devvp);

                ump = VFSTOUFS(mp);
                fs = ump->um_lfs;
                if (fs->lfs_ronly && (mp->mnt_iflag & IMNT_WANTRDWR)) {
                        /*
                         * Changing from read-only to read/write.
                         * Note in the superblocks that we're writing.
                         */
                        fs->lfs_ronly = 0;
                        if (fs->lfs_pflags & LFS_PF_CLEAN) {
                                fs->lfs_pflags &= ~LFS_PF_CLEAN;
                                lfs_writesuper(fs, fs->lfs_sboffs[0]);
                                lfs_writesuper(fs, fs->lfs_sboffs[1]);
                        }
                }
                if (args->fspec == NULL)
                        return EINVAL;
        }

        error = set_statvfs_info(path, UIO_USERSPACE, args->fspec,
            UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
        if (error == 0)
                (void)strncpy(fs->lfs_fsmnt, mp->mnt_stat.f_mntonname,
                              sizeof(fs->lfs_fsmnt));
        return error;

fail:
        vrele(devvp);
        return (error);
}


/*
 * Common code for mount and mountroot
 * LFS specific
 */
int
lfs_mountfs(struct vnode *devvp, struct mount *mp, struct lwp *l)
{
        struct dlfs *tdfs, *dfs, *adfs;
        struct lfs *fs;
        struct ufsmount *ump;
        struct vnode *vp;
        struct buf *bp, *abp;
        dev_t dev;
        int error, i, ronly, fsbsize;
        kauth_cred_t cred;
        CLEANERINFO *cip;
        SEGUSE *sup;
        daddr_t sb_addr;

        cred = l ? l->l_cred : NOCRED;

        /*
         * Flush out any old buffers remaining from a previous use.
         */
        vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
        error = vinvalbuf(devvp, V_SAVE, cred, l, 0, 0);
        VOP_UNLOCK(devvp);
        if (error)
                return (error);

        ronly = (mp->mnt_flag & MNT_RDONLY) != 0;

        /* Don't free random space on error. */
        bp = NULL;
        abp = NULL;
        ump = NULL;

        sb_addr = LFS_LABELPAD / DEV_BSIZE;
        while (1) {
                /* Read in the superblock. */
                error = bread(devvp, sb_addr, LFS_SBPAD, cred, 0, &bp);
                if (error)
                        goto out;
                dfs = (struct dlfs *)bp->b_data;

                /* Check the basics. */
                if (dfs->dlfs_magic != LFS_MAGIC || dfs->dlfs_bsize > MAXBSIZE ||
                    dfs->dlfs_version > LFS_VERSION ||
                    dfs->dlfs_bsize < sizeof(struct dlfs)) {
                        DLOG((DLOG_MOUNT, "lfs_mountfs: primary superblock sanity failed\n"));
                        error = EINVAL;         /* XXX needs translation */
                        goto out;
                }
                if (dfs->dlfs_inodefmt > LFS_MAXINODEFMT) {
                        DLOG((DLOG_MOUNT, "lfs_mountfs: unknown inode format %d\n",
                               dfs->dlfs_inodefmt));
                        error = EINVAL;
                        goto out;
                }

                if (dfs->dlfs_version == 1)
                        fsbsize = DEV_BSIZE;
                else {
                        fsbsize = 1 << dfs->dlfs_ffshift;
                        /*
                         * Could be, if the frag size is large enough, that we
                         * don't have the "real" primary superblock.  If that's
                         * the case, get the real one, and try again.
                         */
                        if (sb_addr != (dfs->dlfs_sboffs[0] << (dfs->dlfs_ffshift - DEV_BSHIFT))) {
                                DLOG((DLOG_MOUNT, "lfs_mountfs: sb daddr"
                                      " 0x%llx is not right, trying 0x%llx\n",
                                      (long long)sb_addr,
                                      (long long)(dfs->dlfs_sboffs[0] << (dfs->dlfs_ffshift - DEV_BSHIFT))));
                                sb_addr = dfs->dlfs_sboffs[0] << (dfs->dlfs_ffshift - DEV_BSHIFT);
                                brelse(bp, 0);
                                continue;
                        }
                }
                break;
        }

        /*
         * Check the second superblock to see which is newer; then mount
         * using the older of the two.  This is necessary to ensure that
         * the filesystem is valid if it was not unmounted cleanly.
         */

        if (dfs->dlfs_sboffs[1] &&
            dfs->dlfs_sboffs[1] - LFS_LABELPAD / fsbsize > LFS_SBPAD / fsbsize)
        {
                error = bread(devvp, dfs->dlfs_sboffs[1] * (fsbsize / DEV_BSIZE),
                        LFS_SBPAD, cred, 0, &abp);
                if (error)
                        goto out;
                adfs = (struct dlfs *)abp->b_data;

                if (dfs->dlfs_version == 1) {
                        /* 1s resolution comparison */
                        if (adfs->dlfs_tstamp < dfs->dlfs_tstamp)
                                tdfs = adfs;
                        else
                                tdfs = dfs;
                } else {
                        /* monotonic infinite-resolution comparison */
                        if (adfs->dlfs_serial < dfs->dlfs_serial)
                                tdfs = adfs;
                        else
                                tdfs = dfs;
                }

                /* Check the basics. */
                if (tdfs->dlfs_magic != LFS_MAGIC ||
                    tdfs->dlfs_bsize > MAXBSIZE ||
                    tdfs->dlfs_version > LFS_VERSION ||
                    tdfs->dlfs_bsize < sizeof(struct dlfs)) {
                        DLOG((DLOG_MOUNT, "lfs_mountfs: alt superblock"
                              " sanity failed\n"));
                        error = EINVAL;         /* XXX needs translation */
                        goto out;
                }
        } else {
                DLOG((DLOG_MOUNT, "lfs_mountfs: invalid alt superblock"
                      " daddr=0x%x\n", dfs->dlfs_sboffs[1]));
                error = EINVAL;
                goto out;
        }

        /* Allocate the mount structure, copy the superblock into it. */
        fs = malloc(sizeof(struct lfs), M_UFSMNT, M_WAITOK | M_ZERO);
        memcpy(&fs->lfs_dlfs, tdfs, sizeof(struct dlfs));

        /* Compatibility */
        if (fs->lfs_version < 2) {
                fs->lfs_sumsize = LFS_V1_SUMMARY_SIZE;
                fs->lfs_ibsize = fs->lfs_bsize;
                fs->lfs_start = fs->lfs_sboffs[0];
                fs->lfs_tstamp = fs->lfs_otstamp;
                fs->lfs_fsbtodb = 0;
        }
        if (fs->lfs_resvseg == 0)
                fs->lfs_resvseg = MIN(fs->lfs_minfreeseg - 1, \
                        MAX(MIN_RESV_SEGS, fs->lfs_minfreeseg / 2 + 1));

        /*
         * If we aren't going to be able to write meaningfully to this
         * filesystem, and were not mounted readonly, bomb out now.
         */
        if (fsbtob(fs, LFS_NRESERVE(fs)) > LFS_MAX_BYTES && !ronly) {
                DLOG((DLOG_MOUNT, "lfs_mount: to mount this filesystem read/write,"
                      " we need BUFPAGES >= %lld\n",
                      (long long)((bufmem_hiwater / bufmem_lowater) *
                                  LFS_INVERSE_MAX_BYTES(
                                          fsbtob(fs, LFS_NRESERVE(fs))) >> PAGE_SHIFT)));
                free(fs, M_UFSMNT);
                error = EFBIG; /* XXX needs translation */
                goto out;
        }

        /* Before rolling forward, lock so vget will sleep for other procs */
        if (l != NULL) {
                fs->lfs_flags = LFS_NOTYET;
                fs->lfs_rfpid = l->l_proc->p_pid;
        }

        ump = malloc(sizeof *ump, M_UFSMNT, M_WAITOK | M_ZERO);
        ump->um_lfs = fs;
        ump->um_ops = &lfs_ufsops;
        ump->um_fstype = UFS1;
        if (sizeof(struct lfs) < LFS_SBPAD) {                   /* XXX why? */
                brelse(bp, BC_INVAL);
                brelse(abp, BC_INVAL);
        } else {
                brelse(bp, 0);
                brelse(abp, 0);
        }
        bp = NULL;
        abp = NULL;


        /* Set up the I/O information */
        fs->lfs_devbsize = DEV_BSIZE;
        fs->lfs_iocount = 0;
        fs->lfs_diropwait = 0;
        fs->lfs_activesb = 0;
        fs->lfs_uinodes = 0;
        fs->lfs_ravail = 0;
        fs->lfs_favail = 0;
        fs->lfs_sbactive = 0;

        /* Set up the ifile and lock aflags */
        fs->lfs_doifile = 0;
        fs->lfs_writer = 0;
        fs->lfs_dirops = 0;
        fs->lfs_nadirop = 0;
        fs->lfs_seglock = 0;
        fs->lfs_pdflush = 0;
        fs->lfs_sleepers = 0;
        fs->lfs_pages = 0;
        rw_init(&fs->lfs_fraglock);
        rw_init(&fs->lfs_iflock);
        cv_init(&fs->lfs_stopcv, "lfsstop");

        /* Set the file system readonly/modify bits. */
        fs->lfs_ronly = ronly;
        if (ronly == 0)
                fs->lfs_fmod = 1;

        /* Initialize the mount structure. */
        dev = devvp->v_rdev;
        mp->mnt_data = ump;
        mp->mnt_stat.f_fsidx.__fsid_val[0] = (long)dev;
        mp->mnt_stat.f_fsidx.__fsid_val[1] = makefstype(MOUNT_LFS);
        mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0];
        mp->mnt_stat.f_namemax = LFS_MAXNAMLEN;
        mp->mnt_stat.f_iosize = fs->lfs_bsize;
        mp->mnt_flag |= MNT_LOCAL;
        mp->mnt_fs_bshift = fs->lfs_bshift;
        ump->um_flags = 0;
        ump->um_mountp = mp;
        ump->um_dev = dev;
        ump->um_devvp = devvp;
        ump->um_bptrtodb = fs->lfs_ffshift - DEV_BSHIFT;
        ump->um_seqinc = fs->lfs_frag;
        ump->um_nindir = fs->lfs_nindir;
        ump->um_lognindir = ffs(fs->lfs_nindir) - 1;
        for (i = 0; i < MAXQUOTAS; i++)
                ump->um_quotas[i] = NULLVP;
        ump->um_maxsymlinklen = fs->lfs_maxsymlinklen;
        ump->um_dirblksiz = DIRBLKSIZ;
        ump->um_maxfilesize = fs->lfs_maxfilesize;
        if (ump->um_maxsymlinklen > 0)
                mp->mnt_iflag |= IMNT_DTYPE;
        devvp->v_specmountpoint = mp;

        /* Set up reserved memory for pageout */
        lfs_setup_resblks(fs);
        /* Set up vdirop tailq */
        TAILQ_INIT(&fs->lfs_dchainhd);
        /* and paging tailq */
        TAILQ_INIT(&fs->lfs_pchainhd);
        /* and delayed segment accounting for truncation list */
        LIST_INIT(&fs->lfs_segdhd);

        /*
         * We use the ifile vnode for almost every operation.  Instead of
         * retrieving it from the hash table each time we retrieve it here,
         * artificially increment the reference count and keep a pointer
         * to it in the incore copy of the superblock.
         */
        if ((error = VFS_VGET(mp, LFS_IFILE_INUM, &vp)) != 0) {
                DLOG((DLOG_MOUNT, "lfs_mountfs: ifile vget failed, error=%d\n", error));
                goto out;
        }
        fs->lfs_ivnode = vp;
        vref(vp);

        /* Set up inode bitmap and order free list */
        lfs_order_freelist(fs);

        /* Set up segment usage flags for the autocleaner. */
        fs->lfs_nactive = 0;
        fs->lfs_suflags = (u_int32_t **)malloc(2 * sizeof(u_int32_t *),
                                                M_SEGMENT, M_WAITOK);
        fs->lfs_suflags[0] = (u_int32_t *)malloc(fs->lfs_nseg * sizeof(u_int32_t),
                                                 M_SEGMENT, M_WAITOK);
        fs->lfs_suflags[1] = (u_int32_t *)malloc(fs->lfs_nseg * sizeof(u_int32_t),
                                                 M_SEGMENT, M_WAITOK);
        memset(fs->lfs_suflags[1], 0, fs->lfs_nseg * sizeof(u_int32_t));
        for (i = 0; i < fs->lfs_nseg; i++) {
                int changed;

                LFS_SEGENTRY(sup, fs, i, bp);
                changed = 0;
                if (!ronly) {
                        if (sup->su_nbytes == 0 &&
                            !(sup->su_flags & SEGUSE_EMPTY)) {
                                sup->su_flags |= SEGUSE_EMPTY;
                                ++changed;
                        } else if (!(sup->su_nbytes == 0) &&
                                   (sup->su_flags & SEGUSE_EMPTY)) {
                                sup->su_flags &= ~SEGUSE_EMPTY;
                                ++changed;
                        }
                        if (sup->su_flags & (SEGUSE_ACTIVE|SEGUSE_INVAL)) {
                                sup->su_flags &= ~(SEGUSE_ACTIVE|SEGUSE_INVAL);
                                ++changed;
                        }
                }
                fs->lfs_suflags[0][i] = sup->su_flags;
                if (changed)
                        LFS_WRITESEGENTRY(sup, fs, i, bp);
                else
                        brelse(bp, 0);
        }

#ifdef LFS_KERNEL_RFW
        lfs_roll_forward(fs, mp, l);
#endif

        /* If writing, sb is not clean; record in case of immediate crash */
        if (!fs->lfs_ronly) {
                fs->lfs_pflags &= ~LFS_PF_CLEAN;
                lfs_writesuper(fs, fs->lfs_sboffs[0]);
                lfs_writesuper(fs, fs->lfs_sboffs[1]);
        }

        /* Allow vget now that roll-forward is complete */
        fs->lfs_flags &= ~(LFS_NOTYET);
        wakeup(&fs->lfs_flags);

        /*
         * Initialize the ifile cleaner info with information from
         * the superblock.
         */
        LFS_CLEANERINFO(cip, fs, bp);
        cip->clean = fs->lfs_nclean;
        cip->dirty = fs->lfs_nseg - fs->lfs_nclean;
        cip->avail = fs->lfs_avail;
        cip->bfree = fs->lfs_bfree;
        (void) LFS_BWRITE_LOG(bp); /* Ifile */

        /*
         * Mark the current segment as ACTIVE, since we're going to
         * be writing to it.
         */
        LFS_SEGENTRY(sup, fs, dtosn(fs, fs->lfs_offset), bp);
        sup->su_flags |= SEGUSE_DIRTY | SEGUSE_ACTIVE;
        fs->lfs_nactive++;
        LFS_WRITESEGENTRY(sup, fs, dtosn(fs, fs->lfs_offset), bp);  /* Ifile */

        /* Now that roll-forward is done, unlock the Ifile */
        vput(vp);

        /* Start the pagedaemon-anticipating daemon */
        if (lfs_writer_daemon == 0 && kthread_create(PRI_BIO, 0, NULL,
            lfs_writerd, NULL, NULL, "lfs_writer") != 0)
                panic("fork lfs_writer");
        /*
         * XXX: Get extra reference to LFS vfsops.  This prevents unload,
         * but also prevents kernel panic due to text being unloaded
         * from below lfs_writerd.  When lfs_writerd can exit, remove
         * this!!!
         */
        vfs_getopsbyname(MOUNT_LFS);

        printf("WARNING: the log-structured file system is experimental\n"
            "WARNING: it may cause system crashes and/or corrupt data\n");

        return (0);

out:
        if (bp)
                brelse(bp, 0);
        if (abp)
                brelse(abp, 0);
        if (ump) {
                free(ump->um_lfs, M_UFSMNT);
                free(ump, M_UFSMNT);
                mp->mnt_data = NULL;
        }

        return (error);
}

/*
 * unmount system call
 */
int
lfs_unmount(struct mount *mp, int mntflags)
{
        struct lwp *l = curlwp;
        struct ufsmount *ump;
        struct lfs *fs;
        int error, flags, ronly;
        vnode_t *vp;

        flags = 0;
        if (mntflags & MNT_FORCE)
                flags |= FORCECLOSE;

        ump = VFSTOUFS(mp);
        fs = ump->um_lfs;

        /* Two checkpoints */
        lfs_segwrite(mp, SEGM_CKP | SEGM_SYNC);
        lfs_segwrite(mp, SEGM_CKP | SEGM_SYNC);

        /* wake up the cleaner so it can die */
        lfs_wakeup_cleaner(fs);
        mutex_enter(&lfs_lock);
        while (fs->lfs_sleepers)
                mtsleep(&fs->lfs_sleepers, PRIBIO + 1, "lfs_sleepers", 0,
                        &lfs_lock);
        mutex_exit(&lfs_lock);

#ifdef QUOTA
        if ((error = quota1_umount(mp, flags)) != 0)
                return (error);
#endif
        if ((error = vflush(mp, fs->lfs_ivnode, flags)) != 0)
                return (error);
        if ((error = VFS_SYNC(mp, 1, l->l_cred)) != 0)
                return (error);
        vp = fs->lfs_ivnode;
        mutex_enter(vp->v_interlock);
        if (LIST_FIRST(&vp->v_dirtyblkhd))
                panic("lfs_unmount: still dirty blocks on ifile vnode");
        mutex_exit(vp->v_interlock);

        /* Explicitly write the superblock, to update serial and pflags */
        fs->lfs_pflags |= LFS_PF_CLEAN;
        lfs_writesuper(fs, fs->lfs_sboffs[0]);
        lfs_writesuper(fs, fs->lfs_sboffs[1]);
        mutex_enter(&lfs_lock);
        while (fs->lfs_iocount)
                mtsleep(&fs->lfs_iocount, PRIBIO + 1, "lfs_umount", 0,
                        &lfs_lock);
        mutex_exit(&lfs_lock);

        /* Finish with the Ifile, now that we're done with it */
        vgone(fs->lfs_ivnode);

        ronly = !fs->lfs_ronly;
        if (ump->um_devvp->v_type != VBAD)
                ump->um_devvp->v_specmountpoint = NULL;
        vn_lock(ump->um_devvp, LK_EXCLUSIVE | LK_RETRY);
        error = VOP_CLOSE(ump->um_devvp,
            ronly ? FREAD : FREAD|FWRITE, NOCRED);
        vput(ump->um_devvp);

        /* Complain about page leakage */
        if (fs->lfs_pages > 0)
                printf("lfs_unmount: still claim %d pages (%d in subsystem)\n",
                        fs->lfs_pages, lfs_subsys_pages);

        /* Free per-mount data structures */
        free(fs->lfs_ino_bitmap, M_SEGMENT);
        free(fs->lfs_suflags[0], M_SEGMENT);
        free(fs->lfs_suflags[1], M_SEGMENT);
        free(fs->lfs_suflags, M_SEGMENT);
        lfs_free_resblks(fs);
        cv_destroy(&fs->lfs_stopcv);
        rw_destroy(&fs->lfs_fraglock);
        rw_destroy(&fs->lfs_iflock);
        free(fs, M_UFSMNT);
        free(ump, M_UFSMNT);

        mp->mnt_data = NULL;
        mp->mnt_flag &= ~MNT_LOCAL;
        return (error);
}

/*
 * Get file system statistics.
 *
 * NB: We don't lock to access the superblock here, because it's not
 * really that important if we get it wrong.
 */
int
lfs_statvfs(struct mount *mp, struct statvfs *sbp)
{
        struct lfs *fs;
        struct ufsmount *ump;

        ump = VFSTOUFS(mp);
        fs = ump->um_lfs;
        if (fs->lfs_magic != LFS_MAGIC)
                panic("lfs_statvfs: magic");

        sbp->f_bsize = fs->lfs_bsize;
        sbp->f_frsize = fs->lfs_fsize;
        sbp->f_iosize = fs->lfs_bsize;
        sbp->f_blocks = LFS_EST_NONMETA(fs) - VTOI(fs->lfs_ivnode)->i_lfs_effnblks;

        sbp->f_bfree = LFS_EST_BFREE(fs);
        KASSERT(sbp->f_bfree <= fs->lfs_dsize);
#if 0
        if (sbp->f_bfree < 0)
                sbp->f_bfree = 0;
#endif

        sbp->f_bresvd = LFS_EST_RSVD(fs);
        if (sbp->f_bfree > sbp->f_bresvd)
                sbp->f_bavail = sbp->f_bfree - sbp->f_bresvd;
        else
                sbp->f_bavail = 0;

        sbp->f_files = fs->lfs_bfree / btofsb(fs, fs->lfs_ibsize) * INOPB(fs);
        sbp->f_ffree = sbp->f_files - fs->lfs_nfiles;
        sbp->f_favail = sbp->f_ffree;
        sbp->f_fresvd = 0;
        copy_statvfs_info(sbp, mp);
        return (0);
}

/*
 * Go through the disk queues to initiate sandbagged IO;
 * go through the inodes to write those that have been modified;
 * initiate the writing of the super block if it has been modified.
 *
 * Note: we are always called with the filesystem marked `MPBUSY'.
 */
int
lfs_sync(struct mount *mp, int waitfor, kauth_cred_t cred)
{
        int error;
        struct lfs *fs;

        fs = VFSTOUFS(mp)->um_lfs;
        if (fs->lfs_ronly)
                return 0;

        /* Snapshots should not hose the syncer */
        /*
         * XXX Sync can block here anyway, since we don't have a very
         * XXX good idea of how much data is pending.  If it's more
         * XXX than a segment and lfs_nextseg is close to the end of
         * XXX the log, we'll likely block.
         */
        mutex_enter(&lfs_lock);
        if (fs->lfs_nowrap && fs->lfs_nextseg < fs->lfs_curseg) {
                mutex_exit(&lfs_lock);
                return 0;
        }
        mutex_exit(&lfs_lock);

        lfs_writer_enter(fs, "lfs_dirops");

        /* All syncs must be checkpoints until roll-forward is implemented. */
        DLOG((DLOG_FLUSH, "lfs_sync at 0x%x\n", fs->lfs_offset));
        error = lfs_segwrite(mp, SEGM_CKP | (waitfor ? SEGM_SYNC : 0));
        lfs_writer_leave(fs);
#ifdef QUOTA
        qsync(mp);
#endif
        return (error);
}

/*
 * Look up an LFS dinode number to find its incore vnode.  If not already
 * in core, read it in from the specified device.  Return the inode locked.
 * Detection and handling of mount points must be done by the calling routine.
 */
int
lfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
{
        struct lfs *fs;
        struct ufs1_dinode *dip;
        struct inode *ip;
        struct buf *bp;
        struct ifile *ifp;
        struct vnode *vp;
        struct ufsmount *ump;
        daddr_t daddr;
        dev_t dev;
        int error, retries;
        struct timespec ts;

        memset(&ts, 0, sizeof ts);      /* XXX gcc */

        ump = VFSTOUFS(mp);
        dev = ump->um_dev;
        fs = ump->um_lfs;

        /*
         * If the filesystem is not completely mounted yet, suspend
         * any access requests (wait for roll-forward to complete).
         */
        mutex_enter(&lfs_lock);
        while ((fs->lfs_flags & LFS_NOTYET) && curproc->p_pid != fs->lfs_rfpid)
                mtsleep(&fs->lfs_flags, PRIBIO+1, "lfs_notyet", 0,
                        &lfs_lock);
        mutex_exit(&lfs_lock);

retry:
        if ((*vpp = ufs_ihashget(dev, ino, LK_EXCLUSIVE)) != NULL)
                return (0);

        error = getnewvnode(VT_LFS, mp, lfs_vnodeop_p, NULL, &vp);
        if (error) {
                *vpp = NULL;
                 return (error);
        }

        mutex_enter(&ufs_hashlock);
        if (ufs_ihashget(dev, ino, 0) != NULL) {
                mutex_exit(&ufs_hashlock);
                ungetnewvnode(vp);
                goto retry;
        }

        /* Translate the inode number to a disk address. */
        if (ino == LFS_IFILE_INUM)
                daddr = fs->lfs_idaddr;
        else {
                /* XXX bounds-check this too */
                LFS_IENTRY(ifp, fs, ino, bp);
                daddr = ifp->if_daddr;
                if (fs->lfs_version > 1) {
                        ts.tv_sec = ifp->if_atime_sec;
                        ts.tv_nsec = ifp->if_atime_nsec;
                }

                brelse(bp, 0);
                if (daddr == LFS_UNUSED_DADDR) {
                        *vpp = NULLVP;
                        mutex_exit(&ufs_hashlock);
                        ungetnewvnode(vp);
                        return (ENOENT);
                }
        }

        /* Allocate/init new vnode/inode. */
        lfs_vcreate(mp, ino, vp);

        /*
         * Put it onto its hash chain and lock it so that other requests for
         * this inode will block if they arrive while we are sleeping waiting
         * for old data structures to be purged or for the contents of the
         * disk portion of this inode to be read.
         */
        ip = VTOI(vp);
        ufs_ihashins(ip);
        mutex_exit(&ufs_hashlock);

        /*
         * XXX
         * This may not need to be here, logically it should go down with
         * the i_devvp initialization.
         * Ask Kirk.
         */
        ip->i_lfs = ump->um_lfs;

        /* Read in the disk contents for the inode, copy into the inode. */
        retries = 0;
    again:
        error = bread(ump->um_devvp, fsbtodb(fs, daddr),
                (fs->lfs_version == 1 ? fs->lfs_bsize : fs->lfs_ibsize),
                NOCRED, 0, &bp);
        if (error) {
                /*
                 * The inode does not contain anything useful, so it would
                 * be misleading to leave it on its hash chain. With mode
                 * still zero, it will be unlinked and returned to the free
                 * list by vput().
                 */
                vput(vp);
                brelse(bp, 0);
                *vpp = NULL;
                return (error);
        }

        dip = lfs_ifind(fs, ino, bp);
        if (dip == NULL) {
                /* Assume write has not completed yet; try again */
                brelse(bp, BC_INVAL);
                ++retries;
                if (retries > LFS_IFIND_RETRIES) {
#ifdef DEBUG
                        /* If the seglock is held look at the bpp to see
                           what is there anyway */
                        mutex_enter(&lfs_lock);
                        if (fs->lfs_seglock > 0) {
                                struct buf **bpp;
                                struct ufs1_dinode *dp;
                                int i;

                                for (bpp = fs->lfs_sp->bpp;
                                     bpp != fs->lfs_sp->cbpp; ++bpp) {
                                        if ((*bpp)->b_vp == fs->lfs_ivnode &&
                                            bpp != fs->lfs_sp->bpp) {
                                                /* Inode block */
                                                printf("lfs_vget: block 0x%" PRIx64 ": ",
                                                       (*bpp)->b_blkno);
                                                dp = (struct ufs1_dinode *)(*bpp)->b_data;
                                                for (i = 0; i < INOPB(fs); i++)
                                                        if (dp[i].di_u.inumber)
                                                                printf("%d ", dp[i].di_u.inumber);
                                                printf("\n");
                                        }
                                }
                        }
                        mutex_exit(&lfs_lock);
#endif /* DEBUG */
                        panic("lfs_vget: dinode not found");
                }
                mutex_enter(&lfs_lock);
                if (fs->lfs_iocount) {
                        DLOG((DLOG_VNODE, "lfs_vget: dinode %d not found, retrying...\n", ino));
                        (void)mtsleep(&fs->lfs_iocount, PRIBIO + 1,
                                      "lfs ifind", 1, &lfs_lock);
                } else
                        retries = LFS_IFIND_RETRIES;
                mutex_exit(&lfs_lock);
                goto again;
        }
        *ip->i_din.ffs1_din = *dip;
        brelse(bp, 0);

        if (fs->lfs_version > 1) {
                ip->i_ffs1_atime = ts.tv_sec;
                ip->i_ffs1_atimensec = ts.tv_nsec;
        }

        lfs_vinit(mp, &vp);

        *vpp = vp;

        KASSERT(VOP_ISLOCKED(vp));

        return (0);
}

/*
 * File handle to vnode
 */
int
lfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
{
        struct lfid lfh;
        struct buf *bp;
        IFILE *ifp;
        int32_t daddr;
        struct lfs *fs;
        vnode_t *vp;

        if (fhp->fid_len != sizeof(struct lfid))
                return EINVAL;

        memcpy(&lfh, fhp, sizeof(lfh));
        if (lfh.lfid_ino < LFS_IFILE_INUM)
                return ESTALE;

        fs = VFSTOUFS(mp)->um_lfs;
        if (lfh.lfid_ident != fs->lfs_ident)
                return ESTALE;

        if (lfh.lfid_ino >
            ((VTOI(fs->lfs_ivnode)->i_ffs1_size >> fs->lfs_bshift) -
             fs->lfs_cleansz - fs->lfs_segtabsz) * fs->lfs_ifpb)
                return ESTALE;

        mutex_enter(&ufs_ihash_lock);
        vp = ufs_ihashlookup(VFSTOUFS(mp)->um_dev, lfh.lfid_ino);
        mutex_exit(&ufs_ihash_lock);
        if (vp == NULL) {
                LFS_IENTRY(ifp, fs, lfh.lfid_ino, bp);
                daddr = ifp->if_daddr;
                brelse(bp, 0);
                if (daddr == LFS_UNUSED_DADDR)
                        return ESTALE;
        }

        return (ufs_fhtovp(mp, &lfh.lfid_ufid, vpp));
}

/*
 * Vnode pointer to File handle
 */
/* ARGSUSED */
int
lfs_vptofh(struct vnode *vp, struct fid *fhp, size_t *fh_size)
{
        struct inode *ip;
        struct lfid lfh;

        if (*fh_size < sizeof(struct lfid)) {
                *fh_size = sizeof(struct lfid);
                return E2BIG;
        }
        *fh_size = sizeof(struct lfid);
        ip = VTOI(vp);
        memset(&lfh, 0, sizeof(lfh));
        lfh.lfid_len = sizeof(struct lfid);
        lfh.lfid_ino = ip->i_number;
        lfh.lfid_gen = ip->i_gen;
        lfh.lfid_ident = ip->i_lfs->lfs_ident;
        memcpy(fhp, &lfh, sizeof(lfh));
        return (0);
}

/*
 * ufs_bmaparray callback function for writing.
 *
 * Since blocks will be written to the new segment anyway,
 * we don't care about current daddr of them.
 */
static bool
lfs_issequential_hole(const struct ufsmount *ump,
    daddr_t daddr0, daddr_t daddr1)
{
        daddr0 = (daddr_t)((int32_t)daddr0); /* XXX ondisk32 */
        daddr1 = (daddr_t)((int32_t)daddr1); /* XXX ondisk32 */

        KASSERT(daddr0 == UNWRITTEN ||
            (0 <= daddr0 && daddr0 <= LFS_MAX_DADDR));
        KASSERT(daddr1 == UNWRITTEN ||
            (0 <= daddr1 && daddr1 <= LFS_MAX_DADDR));

        /* NOTE: all we want to know here is 'hole or not'. */
        /* NOTE: UNASSIGNED is converted to 0 by ufs_bmaparray. */

        /*
         * treat UNWRITTENs and all resident blocks as 'contiguous'
         */
        if (daddr0 != 0 && daddr1 != 0)
                return true;

        /*
         * both are in hole?
         */
        if (daddr0 == 0 && daddr1 == 0)
                return true; /* all holes are 'contiguous' for us. */

        return false;
}

/*
 * lfs_gop_write functions exactly like genfs_gop_write, except that
 * (1) it requires the seglock to be held by its caller, and sp->fip
 *     to be properly initialized (it will return without re-initializing
 *     sp->fip, and without calling lfs_writeseg).
 * (2) it uses the remaining space in the segment, rather than VOP_BMAP,
 *     to determine how large a block it can write at once (though it does
 *     still use VOP_BMAP to find holes in the file);
 * (3) it calls lfs_gatherblock instead of VOP_STRATEGY on its blocks
 *     (leaving lfs_writeseg to deal with the cluster blocks, so we might
 *     now have clusters of clusters, ick.)
 */
static int
lfs_gop_write(struct vnode *vp, struct vm_page **pgs, int npages,
    int flags)
{
        int i, error, run, haveeof = 0;
        int fs_bshift;
        vaddr_t kva;
        off_t eof, offset, startoffset = 0;
        size_t bytes, iobytes, skipbytes;
        bool async = (flags & PGO_SYNCIO) == 0;
        daddr_t lbn, blkno;
        struct vm_page *pg;
        struct buf *mbp, *bp;
        struct vnode *devvp = VTOI(vp)->i_devvp;
        struct inode *ip = VTOI(vp);
        struct lfs *fs = ip->i_lfs;
        struct segment *sp = fs->lfs_sp;
        UVMHIST_FUNC("lfs_gop_write"); UVMHIST_CALLED(ubchist);

        ASSERT_SEGLOCK(fs);

        /* The Ifile lives in the buffer cache */
        KASSERT(vp != fs->lfs_ivnode);

        /*
         * We don't want to fill the disk before the cleaner has a chance
         * to make room for us.  If we're in danger of doing that, fail
         * with EAGAIN.  The caller will have to notice this, unlock
         * so the cleaner can run, relock and try again.
         *
         * We must write everything, however, if our vnode is being
         * reclaimed.
         */
        if (LFS_STARVED_FOR_SEGS(fs) && vp != fs->lfs_flushvp)
                goto tryagain;

        /*
         * Sometimes things slip past the filters in lfs_putpages,
         * and the pagedaemon tries to write pages---problem is
         * that the pagedaemon never acquires the segment lock.
         *
         * Alternatively, pages that were clean when we called
         * genfs_putpages may have become dirty in the meantime.  In this
         * case the segment header is not properly set up for blocks
         * to be added to it.
         *
         * Unbusy and unclean the pages, and put them on the ACTIVE
         * queue under the hypothesis that they couldn't have got here
         * unless they were modified *quite* recently.
         *
         * XXXUBC that last statement is an oversimplification of course.
         */
        if (!LFS_SEGLOCK_HELD(fs) ||
            (ip->i_lfs_iflags & LFSI_NO_GOP_WRITE) ||
            (pgs[0]->offset & fs->lfs_bmask) != 0) {
                goto tryagain;
        }

        UVMHIST_LOG(ubchist, "vp %p pgs %p npages %d flags 0x%x",
            vp, pgs, npages, flags);

        GOP_SIZE(vp, vp->v_size, &eof, 0);
        haveeof = 1;

        if (vp->v_type == VREG)
                fs_bshift = vp->v_mount->mnt_fs_bshift;
        else
                fs_bshift = DEV_BSHIFT;
        error = 0;
        pg = pgs[0];
        startoffset = pg->offset;
        KASSERT(eof >= 0);

        if (startoffset >= eof) {
                goto tryagain;
        } else
                bytes = MIN(npages << PAGE_SHIFT, eof - startoffset);
        skipbytes = 0;

        KASSERT(bytes != 0);

        /* Swap PG_DELWRI for PG_PAGEOUT */
        for (i = 0; i < npages; i++) {
                if (pgs[i]->flags & PG_DELWRI) {
                        KASSERT(!(pgs[i]->flags & PG_PAGEOUT));
                        pgs[i]->flags &= ~PG_DELWRI;
                        pgs[i]->flags |= PG_PAGEOUT;
                        uvm_pageout_start(1);
                        mutex_enter(&uvm_pageqlock);
                        uvm_pageunwire(pgs[i]);
                        mutex_exit(&uvm_pageqlock);
                }
        }

        /*
         * Check to make sure we're starting on a block boundary.
         * We'll check later to make sure we always write entire
         * blocks (or fragments).
         */
        if (startoffset & fs->lfs_bmask)
                printf("%" PRId64 " & %" PRId64 " = %" PRId64 "\n",
                       startoffset, fs->lfs_bmask,
                       startoffset & fs->lfs_bmask);
        KASSERT((startoffset & fs->lfs_bmask) == 0);
        if (bytes & fs->lfs_ffmask) {
                printf("lfs_gop_write: asked to write %ld bytes\n", (long)bytes);
                panic("lfs_gop_write: non-integer blocks");
        }

        /*
         * We could deadlock here on pager_map with UVMPAGER_MAPIN_WAITOK.
         * If we would, write what we have and try again.  If we don't
         * have anything to write, we'll have to sleep.
         */
        if ((kva = uvm_pagermapin(pgs, npages, UVMPAGER_MAPIN_WRITE |
                                      (((SEGSUM *)(sp->segsum))->ss_nfinfo < 1 ?
                                       UVMPAGER_MAPIN_WAITOK : 0))) == 0x0) {
                DLOG((DLOG_PAGE, "lfs_gop_write: forcing write\n"));
#if 0
                      " with nfinfo=%d at offset 0x%x\n",
                      (int)((SEGSUM *)(sp->segsum))->ss_nfinfo,
                      (unsigned)fs->lfs_offset));
#endif
                lfs_updatemeta(sp);
                lfs_release_finfo(fs);
                (void) lfs_writeseg(fs, sp);

                lfs_acquire_finfo(fs, ip->i_number, ip->i_gen);

                /*
                 * Having given up all of the pager_map we were holding,
                 * we can now wait for aiodoned to reclaim it for us
                 * without fear of deadlock.
                 */
                kva = uvm_pagermapin(pgs, npages, UVMPAGER_MAPIN_WRITE |
                                     UVMPAGER_MAPIN_WAITOK);
        }

        mbp = getiobuf(NULL, true);
        UVMHIST_LOG(ubchist, "vp %p mbp %p num now %d bytes 0x%x",
            vp, mbp, vp->v_numoutput, bytes);
        mbp->b_bufsize = npages << PAGE_SHIFT;
        mbp->b_data = (void *)kva;
        mbp->b_resid = mbp->b_bcount = bytes;
        mbp->b_cflags = BC_BUSY|BC_AGE;
        mbp->b_iodone = uvm_aio_biodone;

        bp = NULL;
        for (offset = startoffset;
            bytes > 0;
            offset += iobytes, bytes -= iobytes) {
                lbn = offset >> fs_bshift;
                error = ufs_bmaparray(vp, lbn, &blkno, NULL, NULL, &run,
                    lfs_issequential_hole);
                if (error) {
                        UVMHIST_LOG(ubchist, "ufs_bmaparray() -> %d",
                            error,0,0,0);
                        skipbytes += bytes;
                        bytes = 0;
                        break;
                }

                iobytes = MIN((((off_t)lbn + 1 + run) << fs_bshift) - offset,
                    bytes);
                if (blkno == (daddr_t)-1) {
                        skipbytes += iobytes;
                        continue;
                }

                /*
                 * Discover how much we can really pack into this buffer.
                 */
                /* If no room in the current segment, finish it up */
                if (sp->sum_bytes_left < sizeof(int32_t) ||
                    sp->seg_bytes_left < (1 << fs->lfs_bshift)) {
                        int vers;

                        lfs_updatemeta(sp);
                        vers = sp->fip->fi_version;
                        lfs_release_finfo(fs);
                        (void) lfs_writeseg(fs, sp);

                        lfs_acquire_finfo(fs, ip->i_number, vers);
                }
                /* Check both for space in segment and space in segsum */
                iobytes = MIN(iobytes, (sp->seg_bytes_left >> fs_bshift)
                                        << fs_bshift);
                iobytes = MIN(iobytes, (sp->sum_bytes_left / sizeof(int32_t))
                                       << fs_bshift);
                KASSERT(iobytes > 0);

                /* if it's really one i/o, don't make a second buf */
                if (offset == startoffset && iobytes == bytes) {
                        bp = mbp;
                        /* 
                         * All the LFS output is done by the segwriter.  It
                         * will increment numoutput by one for all the bufs it
                         * recieves.  However this buffer needs one extra to
                         * account for aiodone.
                         */
                        mutex_enter(vp->v_interlock);
                        vp->v_numoutput++;
                        mutex_exit(vp->v_interlock);
                } else {
                        bp = getiobuf(NULL, true);
                        UVMHIST_LOG(ubchist, "vp %p bp %p num now %d",
                            vp, bp, vp->v_numoutput, 0);
                        nestiobuf_setup(mbp, bp, offset - pg->offset, iobytes);
                        /*
                         * LFS doesn't like async I/O here, dies with
                         * and assert in lfs_bwrite().  Is that assert
                         * valid?  I retained non-async behaviour when
                         * converted this to use nestiobuf --pooka
                         */
                        bp->b_flags &= ~B_ASYNC;
                }

                /* XXX This is silly ... is this necessary? */
                mutex_enter(&bufcache_lock);
                mutex_enter(vp->v_interlock);
                bgetvp(vp, bp);
                mutex_exit(vp->v_interlock);
                mutex_exit(&bufcache_lock);

                bp->b_lblkno = lblkno(fs, offset);
                bp->b_private = mbp;
                if (devvp->v_type == VBLK) {
                        bp->b_dev = devvp->v_rdev;
                }
                VOP_BWRITE(bp->b_vp, bp);
                while (lfs_gatherblock(sp, bp, NULL))
                        continue;
        }

        nestiobuf_done(mbp, skipbytes, error);
        if (skipbytes) {
                UVMHIST_LOG(ubchist, "skipbytes %d", skipbytes, 0,0,0);
        }
        UVMHIST_LOG(ubchist, "returning 0", 0,0,0,0);

        if (!async) {
                /* Start a segment write. */
                UVMHIST_LOG(ubchist, "flushing", 0,0,0,0);
                mutex_enter(&lfs_lock);
                lfs_flush(fs, 0, 1);
                mutex_exit(&lfs_lock);
        }
        return (0);

    tryagain:
        /*
         * We can't write the pages, for whatever reason.
         * Clean up after ourselves, and make the caller try again.
         */
        mutex_enter(vp->v_interlock);

        /* Tell why we're here, if we know */
        if (ip->i_lfs_iflags & LFSI_NO_GOP_WRITE) {
                DLOG((DLOG_PAGE, "lfs_gop_write: clean pages dirtied\n"));
        } else if ((pgs[0]->offset & fs->lfs_bmask) != 0) {
                DLOG((DLOG_PAGE, "lfs_gop_write: not on block boundary\n"));
        } else if (haveeof && startoffset >= eof) {
                DLOG((DLOG_PAGE, "lfs_gop_write: ino %d start 0x%" PRIx64
                      " eof 0x%" PRIx64 " npages=%d\n", VTOI(vp)->i_number,
                      pgs[0]->offset, eof, npages));
        } else if (LFS_STARVED_FOR_SEGS(fs)) {
                DLOG((DLOG_PAGE, "lfs_gop_write: avail too low\n"));
        } else {
                DLOG((DLOG_PAGE, "lfs_gop_write: seglock not held\n"));
        }

        mutex_enter(&uvm_pageqlock);
        for (i = 0; i < npages; i++) {
                pg = pgs[i];

                if (pg->flags & PG_PAGEOUT)
                        uvm_pageout_done(1);
                if (pg->flags & PG_DELWRI) {
                        uvm_pageunwire(pg);
                }
                uvm_pageactivate(pg);
                pg->flags &= ~(PG_CLEAN|PG_DELWRI|PG_PAGEOUT|PG_RELEASED);
                DLOG((DLOG_PAGE, "pg[%d] = %p (vp %p off %" PRIx64 ")\n", i, pg,
                        vp, pg->offset));
                DLOG((DLOG_PAGE, "pg[%d]->flags = %x\n", i, pg->flags));
                DLOG((DLOG_PAGE, "pg[%d]->pqflags = %x\n", i, pg->pqflags));
                DLOG((DLOG_PAGE, "pg[%d]->uanon = %p\n", i, pg->uanon));
                DLOG((DLOG_PAGE, "pg[%d]->uobject = %p\n", i, pg->uobject));
                DLOG((DLOG_PAGE, "pg[%d]->wire_count = %d\n", i,
                      pg->wire_count));
                DLOG((DLOG_PAGE, "pg[%d]->loan_count = %d\n", i,
                      pg->loan_count));
        }
        /* uvm_pageunbusy takes care of PG_BUSY, PG_WANTED */
        uvm_page_unbusy(pgs, npages);
        mutex_exit(&uvm_pageqlock);
        mutex_exit(vp->v_interlock);
        return EAGAIN;
}

/*
 * finish vnode/inode initialization.
 * used by lfs_vget and lfs_fastvget.
 */
void
lfs_vinit(struct mount *mp, struct vnode **vpp)
{
        struct vnode *vp = *vpp;
        struct inode *ip = VTOI(vp);
        struct ufsmount *ump = VFSTOUFS(mp);
        struct lfs *fs = ump->um_lfs;
        int i;

        ip->i_mode = ip->i_ffs1_mode;
        ip->i_nlink = ip->i_ffs1_nlink;
        ip->i_lfs_osize = ip->i_size = ip->i_ffs1_size;
        ip->i_flags = ip->i_ffs1_flags;
        ip->i_gen = ip->i_ffs1_gen;
        ip->i_uid = ip->i_ffs1_uid;
        ip->i_gid = ip->i_ffs1_gid;

        ip->i_lfs_effnblks = ip->i_ffs1_blocks;
        ip->i_lfs_odnlink = ip->i_ffs1_nlink;

        /*
         * Initialize the vnode from the inode, check for aliases.  In all
         * cases re-init ip, the underlying vnode/inode may have changed.
         */
        ufs_vinit(mp, lfs_specop_p, lfs_fifoop_p, &vp);
        ip = VTOI(vp);

        memset(ip->i_lfs_fragsize, 0, NDADDR * sizeof(*ip->i_lfs_fragsize));
        if (vp->v_type != VLNK || ip->i_size >= ip->i_ump->um_maxsymlinklen) {
#ifdef DEBUG
                for (i = (ip->i_size + fs->lfs_bsize - 1) >> fs->lfs_bshift;
                    i < NDADDR; i++) {
                        if ((vp->v_type == VBLK || vp->v_type == VCHR) &&
                            i == 0)
                                continue;
                        if (ip->i_ffs1_db[i] != 0) {
inconsistent:
                                lfs_dump_dinode(ip->i_din.ffs1_din);
                                panic("inconsistent inode");
                        }
                }
                for ( ; i < NDADDR + NIADDR; i++) {
                        if (ip->i_ffs1_ib[i - NDADDR] != 0) {
                                goto inconsistent;
                        }
                }
#endif /* DEBUG */
                for (i = 0; i < NDADDR; i++)
                        if (ip->i_ffs1_db[i] != 0)
                                ip->i_lfs_fragsize[i] = blksize(fs, ip, i);
        }

#ifdef DIAGNOSTIC
        if (vp->v_type == VNON) {
# ifdef DEBUG
                lfs_dump_dinode(ip->i_din.ffs1_din);
# endif
                panic("lfs_vinit: ino %llu is type VNON! (ifmt=%o)\n",
                      (unsigned long long)ip->i_number,
                      (ip->i_mode & IFMT) >> 12);
        }
#endif /* DIAGNOSTIC */

        /*
         * Finish inode initialization now that aliasing has been resolved.
         */

        ip->i_devvp = ump->um_devvp;
        vref(ip->i_devvp);
        genfs_node_init(vp, &lfs_genfsops);
        uvm_vnp_setsize(vp, ip->i_size);

        /* Initialize hiblk from file size */
        ip->i_lfs_hiblk = lblkno(ip->i_lfs, ip->i_size + ip->i_lfs->lfs_bsize - 1) - 1;

        *vpp = vp;
}

/*
 * Resize the filesystem to contain the specified number of segments.
 */
int
lfs_resize_fs(struct lfs *fs, int newnsegs)
{
        SEGUSE *sup;
        struct buf *bp, *obp;
        daddr_t olast, nlast, ilast, noff, start, end;
        struct vnode *ivp;
        struct inode *ip;
        int error, badnews, inc, oldnsegs;
        int sbbytes, csbbytes, gain, cgain;
        int i;

        /* Only support v2 and up */
        if (fs->lfs_version < 2)
                return EOPNOTSUPP;

        /* If we're doing nothing, do it fast */
        oldnsegs = fs->lfs_nseg;
        if (newnsegs == oldnsegs)
                return 0;

        /* We always have to have two superblocks */
        if (newnsegs <= dtosn(fs, fs->lfs_sboffs[1]))
                return EFBIG;

        ivp = fs->lfs_ivnode;
        ip = VTOI(ivp);
        error = 0;

        /* Take the segment lock so no one else calls lfs_newseg() */
        lfs_seglock(fs, SEGM_PROT);

        /*
         * Make sure the segments we're going to be losing, if any,
         * are in fact empty.  We hold the seglock, so their status
         * cannot change underneath us.  Count the superblocks we lose,
         * while we're at it.
         */
        sbbytes = csbbytes = 0;
        cgain = 0;
        for (i = newnsegs; i < oldnsegs; i++) {
                LFS_SEGENTRY(sup, fs, i, bp);
                badnews = sup->su_nbytes || !(sup->su_flags & SEGUSE_INVAL);
                if (sup->su_flags & SEGUSE_SUPERBLOCK)
                        sbbytes += LFS_SBPAD;
                if (!(sup->su_flags & SEGUSE_DIRTY)) {
                        ++cgain;
                        if (sup->su_flags & SEGUSE_SUPERBLOCK)
                                csbbytes += LFS_SBPAD;
                }
                brelse(bp, 0);
                if (badnews) {
                        error = EBUSY;
                        goto out;
                }
        }

        /* Note old and new segment table endpoints, and old ifile size */
        olast = fs->lfs_cleansz + fs->lfs_segtabsz;
        nlast = howmany(newnsegs, fs->lfs_sepb) + fs->lfs_cleansz;
        ilast = ivp->v_size >> fs->lfs_bshift;
        noff = nlast - olast;

        /*
         * Make sure no one can use the Ifile while we change it around.
         * Even after taking the iflock we need to make sure no one still
         * is holding Ifile buffers, so we get each one, to drain them.
         * (XXX this could be done better.)
         */
        rw_enter(&fs->lfs_iflock, RW_WRITER);
        vn_lock(ivp, LK_EXCLUSIVE | LK_RETRY);
        for (i = 0; i < ilast; i++) {
                bread(ivp, i, fs->lfs_bsize, NOCRED, 0, &bp);
                brelse(bp, 0);
        }

        /* Allocate new Ifile blocks */
        for (i = ilast; i < ilast + noff; i++) {
                if (lfs_balloc(ivp, i * fs->lfs_bsize, fs->lfs_bsize, NOCRED, 0,
                               &bp) != 0)
                        panic("balloc extending ifile");
                memset(bp->b_data, 0, fs->lfs_bsize);
                VOP_BWRITE(bp->b_vp, bp);
        }

        /* Register new ifile size */
        ip->i_size += noff * fs->lfs_bsize; 
        ip->i_ffs1_size = ip->i_size;
        uvm_vnp_setsize(ivp, ip->i_size);

        /* Copy the inode table to its new position */
        if (noff != 0) {
                if (noff < 0) {
                        start = nlast;
                        end = ilast + noff;
                        inc = 1;
                } else {
                        start = ilast + noff - 1;
                        end = nlast - 1;
                        inc = -1;
                }
                for (i = start; i != end; i += inc) {
                        if (bread(ivp, i, fs->lfs_bsize, NOCRED,
                            B_MODIFY, &bp) != 0)
                                panic("resize: bread dst blk failed");
                        if (bread(ivp, i - noff, fs->lfs_bsize,
                            NOCRED, 0, &obp))
                                panic("resize: bread src blk failed");
                        memcpy(bp->b_data, obp->b_data, fs->lfs_bsize);
                        VOP_BWRITE(bp->b_vp, bp);
                        brelse(obp, 0);
                }
        }

        /* If we are expanding, write the new empty SEGUSE entries */
        if (newnsegs > oldnsegs) {
                for (i = oldnsegs; i < newnsegs; i++) {
                        if ((error = bread(ivp, i / fs->lfs_sepb +
                                           fs->lfs_cleansz, fs->lfs_bsize,
                                           NOCRED, B_MODIFY, &bp)) != 0)
                                panic("lfs: ifile read: %d", error);
                        while ((i + 1) % fs->lfs_sepb && i < newnsegs) {
                                sup = &((SEGUSE *)bp->b_data)[i % fs->lfs_sepb];
                                memset(sup, 0, sizeof(*sup));
                                i++;
                        }
                        VOP_BWRITE(bp->b_vp, bp);
                }
        }

        /* Zero out unused superblock offsets */
        for (i = 2; i < LFS_MAXNUMSB; i++)
                if (dtosn(fs, fs->lfs_sboffs[i]) >= newnsegs)
                        fs->lfs_sboffs[i] = 0x0;

        /*
         * Correct superblock entries that depend on fs size.
         * The computations of these are as follows:
         *
         * size  = segtod(fs, nseg)
         * dsize = segtod(fs, nseg - minfreeseg) - btofsb(#super * LFS_SBPAD)
         * bfree = dsize - btofsb(fs, bsize * nseg / 2) - blocks_actually_used
         * avail = segtod(fs, nclean) - btofsb(#clean_super * LFS_SBPAD)
         *         + (segtod(fs, 1) - (offset - curseg))
         *         - segtod(fs, minfreeseg - (minfreeseg / 2))
         *
         * XXX - we should probably adjust minfreeseg as well.
         */
        gain = (newnsegs - oldnsegs);
        fs->lfs_nseg = newnsegs;
        fs->lfs_segtabsz = nlast - fs->lfs_cleansz;
        fs->lfs_size += gain * btofsb(fs, fs->lfs_ssize);
        fs->lfs_dsize += gain * btofsb(fs, fs->lfs_ssize) - btofsb(fs, sbbytes);
        fs->lfs_bfree += gain * btofsb(fs, fs->lfs_ssize) - btofsb(fs, sbbytes)
                       - gain * btofsb(fs, fs->lfs_bsize / 2);
        if (gain > 0) {
                fs->lfs_nclean += gain;
                fs->lfs_avail += gain * btofsb(fs, fs->lfs_ssize);
        } else {
                fs->lfs_nclean -= cgain;
                fs->lfs_avail -= cgain * btofsb(fs, fs->lfs_ssize) -
                                 btofsb(fs, csbbytes);
        }

        /* Resize segment flag cache */
        fs->lfs_suflags[0] = (u_int32_t *)realloc(fs->lfs_suflags[0],
                                                  fs->lfs_nseg * sizeof(u_int32_t),
                                                  M_SEGMENT, M_WAITOK);
        fs->lfs_suflags[1] = (u_int32_t *)realloc(fs->lfs_suflags[1],
                                                  fs->lfs_nseg * sizeof(u_int32_t),
                                                  M_SEGMENT, M_WAITOK);
        for (i = oldnsegs; i < newnsegs; i++)
                fs->lfs_suflags[0][i] = fs->lfs_suflags[1][i] = 0x0;

        /* Truncate Ifile if necessary */
        if (noff < 0)
                lfs_truncate(ivp, ivp->v_size + (noff << fs->lfs_bshift), 0,
                    NOCRED);

        /* Update cleaner info so the cleaner can die */
        bread(ivp, 0, fs->lfs_bsize, NOCRED, B_MODIFY, &bp);
        ((CLEANERINFO *)bp->b_data)->clean = fs->lfs_nclean;
        ((CLEANERINFO *)bp->b_data)->dirty = fs->lfs_nseg - fs->lfs_nclean;
        VOP_BWRITE(bp->b_vp, bp);

        /* Let Ifile accesses proceed */
        VOP_UNLOCK(ivp);
        rw_exit(&fs->lfs_iflock);

    out:
        lfs_segunlock(fs);
        return error;
}