/*-
 *  modified for EXT2FS support in Lites 1.1
 *
 *  Aug 1995, Godmar Back (gback@cs.utah.edu)
 *  University of Utah, Department of Computer Science
 */
/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/endian.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/sdt.h>
#include <sys/stat.h>
#include <sys/mutex.h>

#include <geom/geom.h>
#include <geom/geom_vfs.h>

#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/ext2_mount.h>
#include <fs/ext2fs/inode.h>

#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/ext2_dinode.h>
#include <fs/ext2fs/ext2_extern.h>
#include <fs/ext2fs/ext2_extents.h>

SDT_PROVIDER_DECLARE(ext2fs);
/*
 * ext2fs trace probe:
 * arg0: verbosity. Higher numbers give more verbose messages
 * arg1: Textual message
 */
SDT_PROBE_DEFINE2(ext2fs, , vfsops, trace, "int", "char*");
SDT_PROBE_DEFINE2(ext2fs, , vfsops, ext2_cg_validate_error, "char*", "int");
SDT_PROBE_DEFINE1(ext2fs, , vfsops, ext2_compute_sb_data_error, "char*");

static int      ext2_flushfiles(struct mount *mp, int flags, struct thread *td);
static int      ext2_mountfs(struct vnode *, struct mount *);
static int      ext2_reload(struct mount *mp, struct thread *td);
static int      ext2_sbupdate(struct ext2mount *, int);
static int      ext2_cgupdate(struct ext2mount *, int);
static vfs_unmount_t            ext2_unmount;
static vfs_root_t               ext2_root;
static vfs_statfs_t             ext2_statfs;
static vfs_sync_t               ext2_sync;
static vfs_vget_t               ext2_vget;
static vfs_fhtovp_t             ext2_fhtovp;
static vfs_mount_t              ext2_mount;

MALLOC_DEFINE(M_EXT2NODE, "ext2_node", "EXT2 vnode private part");
static MALLOC_DEFINE(M_EXT2MNT, "ext2_mount", "EXT2 mount structure");

static struct vfsops ext2fs_vfsops = {
        .vfs_fhtovp =           ext2_fhtovp,
        .vfs_mount =            ext2_mount,
        .vfs_root =             ext2_root,      /* root inode via vget */
        .vfs_statfs =           ext2_statfs,
        .vfs_sync =             ext2_sync,
        .vfs_unmount =          ext2_unmount,
        .vfs_vget =             ext2_vget,
};

VFS_SET(ext2fs_vfsops, ext2fs, 0);

static int      ext2_check_sb_compat(struct ext2fs *es, struct cdev *dev,
                    int ronly);
static int      ext2_compute_sb_data(struct vnode * devvp,
                    struct ext2fs * es, struct m_ext2fs * fs);

static const char *ext2_opts[] = { "acls", "async", "noatime", "noclusterr",
    "noclusterw", "noexec", "export", "force", "from", "multilabel",
    "suiddir", "nosymfollow", "sync", "union", NULL };

/*
 * VFS Operations.
 *
 * mount system call
 */
static int
ext2_mount(struct mount *mp)
{
        struct vfsoptlist *opts;
        struct vnode *devvp;
        struct thread *td;
        struct ext2mount *ump = NULL;
        struct m_ext2fs *fs;
        struct nameidata nd, *ndp = &nd;
        accmode_t accmode;
        char *path, *fspec;
        int error, flags, len;

        td = curthread;
        opts = mp->mnt_optnew;

        if (vfs_filteropt(opts, ext2_opts))
                return (EINVAL);

        vfs_getopt(opts, "fspath", (void **)&path, NULL);
        /* Double-check the length of path.. */
        if (strlen(path) >= MAXMNTLEN)
                return (ENAMETOOLONG);

        fspec = NULL;
        error = vfs_getopt(opts, "from", (void **)&fspec, &len);
        if (!error && fspec[len - 1] != '\0')
                return (EINVAL);

        /*
         * If updating, check whether changing from read-only to
         * read/write; if there is no device name, that's all we do.
         */
        if (mp->mnt_flag & MNT_UPDATE) {
                ump = VFSTOEXT2(mp);
                fs = ump->um_e2fs;
                error = 0;
                if (fs->e2fs_ronly == 0 &&
                    vfs_flagopt(opts, "ro", NULL, 0)) {
                        error = VFS_SYNC(mp, MNT_WAIT);
                        if (error)
                                return (error);
                        flags = WRITECLOSE;
                        if (mp->mnt_flag & MNT_FORCE)
                                flags |= FORCECLOSE;
                        error = ext2_flushfiles(mp, flags, td);
                        if (error == 0 && fs->e2fs_wasvalid &&
                            ext2_cgupdate(ump, MNT_WAIT) == 0) {
                                fs->e2fs->e2fs_state =
                                    htole16((le16toh(fs->e2fs->e2fs_state) |
                                    E2FS_ISCLEAN));
                                ext2_sbupdate(ump, MNT_WAIT);
                        }
                        fs->e2fs_ronly = 1;
                        vfs_flagopt(opts, "ro", &mp->mnt_flag, MNT_RDONLY);
                        g_topology_lock();
                        g_access(ump->um_cp, 0, -1, 0);
                        g_topology_unlock();
                }
                if (!error && (mp->mnt_flag & MNT_RELOAD))
                        error = ext2_reload(mp, td);
                if (error)
                        return (error);
                devvp = ump->um_devvp;
                if (fs->e2fs_ronly && !vfs_flagopt(opts, "ro", NULL, 0)) {
                        if (ext2_check_sb_compat(fs->e2fs, devvp->v_rdev, 0))
                                return (EPERM);

                        /*
                         * If upgrade to read-write by non-root, then verify
                         * that user has necessary permissions on the device.
                         */
                        vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
                        error = VOP_ACCESS(devvp, VREAD | VWRITE,
                            td->td_ucred, td);
                        if (error)
                                error = priv_check(td, PRIV_VFS_MOUNT_PERM);
                        if (error) {
                                VOP_UNLOCK(devvp);
                                return (error);
                        }
                        VOP_UNLOCK(devvp);
                        g_topology_lock();
                        error = g_access(ump->um_cp, 0, 1, 0);
                        g_topology_unlock();
                        if (error)
                                return (error);

                        if ((le16toh(fs->e2fs->e2fs_state) & E2FS_ISCLEAN) == 0 ||
                            (le16toh(fs->e2fs->e2fs_state) & E2FS_ERRORS)) {
                                if (mp->mnt_flag & MNT_FORCE) {
                                        printf(
"WARNING: %s was not properly dismounted\n", fs->e2fs_fsmnt);
                                } else {
                                        printf(
"WARNING: R/W mount of %s denied.  Filesystem is not clean - run fsck\n",
                                            fs->e2fs_fsmnt);
                                        return (EPERM);
                                }
                        }
                        fs->e2fs->e2fs_state =
                            htole16(le16toh(fs->e2fs->e2fs_state) & ~E2FS_ISCLEAN);
                        (void)ext2_cgupdate(ump, MNT_WAIT);
                        fs->e2fs_ronly = 0;
                        MNT_ILOCK(mp);
                        mp->mnt_flag &= ~MNT_RDONLY;
                        MNT_IUNLOCK(mp);
                }
                if (vfs_flagopt(opts, "export", NULL, 0)) {
                        /* Process export requests in vfs_mount.c. */
                        return (error);
                }
        }

        /*
         * Not an update, or updating the name: look up the name
         * and verify that it refers to a sensible disk device.
         */
        if (fspec == NULL)
                return (EINVAL);
        NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, fspec);
        if ((error = namei(ndp)) != 0)
                return (error);
        NDFREE_PNBUF(ndp);
        devvp = ndp->ni_vp;

        if (!vn_isdisk_error(devvp, &error)) {
                vput(devvp);
                return (error);
        }

        /*
         * If mount by non-root, then verify that user has necessary
         * permissions on the device.
         *
         * XXXRW: VOP_ACCESS() enough?
         */
        accmode = VREAD;
        if ((mp->mnt_flag & MNT_RDONLY) == 0)
                accmode |= VWRITE;
        error = VOP_ACCESS(devvp, accmode, td->td_ucred, td);
        if (error)
                error = priv_check(td, PRIV_VFS_MOUNT_PERM);
        if (error) {
                vput(devvp);
                return (error);
        }

        if ((mp->mnt_flag & MNT_UPDATE) == 0) {
                error = ext2_mountfs(devvp, mp);
        } else {
                if (devvp != ump->um_devvp) {
                        vput(devvp);
                        return (EINVAL);        /* needs translation */
                } else
                        vput(devvp);
        }
        if (error) {
                vrele(devvp);
                return (error);
        }
        ump = VFSTOEXT2(mp);
        fs = ump->um_e2fs;

        /*
         * Note that this strncpy() is ok because of a check at the start
         * of ext2_mount().
         */
        strncpy(fs->e2fs_fsmnt, path, MAXMNTLEN);
        fs->e2fs_fsmnt[MAXMNTLEN - 1] = '\0';
        vfs_mountedfrom(mp, fspec);
        return (0);
}

static int
ext2_check_sb_compat(struct ext2fs *es, struct cdev *dev, int ronly)
{
        uint32_t i, mask;

        if (le16toh(es->e2fs_magic) != E2FS_MAGIC) {
                printf("ext2fs: %s: wrong magic number %#x (expected %#x)\n",
                    devtoname(dev), le16toh(es->e2fs_magic), E2FS_MAGIC);
                return (1);
        }
        if (le32toh(es->e2fs_rev) > E2FS_REV0) {
                mask = le32toh(es->e2fs_features_incompat) & ~(EXT2F_INCOMPAT_SUPP);
                if (mask) {
                        printf("WARNING: mount of %s denied due to "
                            "unsupported optional features:\n", devtoname(dev));
                        for (i = 0;
                            i < sizeof(incompat)/sizeof(struct ext2_feature);
                            i++)
                                if (mask & incompat[i].mask)
                                        printf("%s ", incompat[i].name);
                        printf("\n");
                        return (1);
                }
                mask = le32toh(es->e2fs_features_rocompat) & ~EXT2F_ROCOMPAT_SUPP;
                if (!ronly && mask) {
                        printf("WARNING: R/W mount of %s denied due to "
                            "unsupported optional features:\n", devtoname(dev));
                        for (i = 0;
                            i < sizeof(ro_compat)/sizeof(struct ext2_feature);
                            i++)
                                if (mask & ro_compat[i].mask)
                                        printf("%s ", ro_compat[i].name);
                        printf("\n");
                        return (1);
                }
        }
        return (0);
}

static e4fs_daddr_t
ext2_cg_location(struct m_ext2fs *fs, int number)
{
        int cg, descpb, logical_sb, has_super = 0;

        /*
         * Adjust logical superblock block number.
         * Godmar thinks: if the blocksize is greater than 1024, then
         * the superblock is logically part of block zero.
         */
        logical_sb = fs->e2fs_bsize > SBLOCKSIZE ? 0 : 1;

        if (!EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_META_BG) ||
            number < le32toh(fs->e2fs->e3fs_first_meta_bg))
                return (logical_sb + number + 1);

        if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT))
                descpb = fs->e2fs_bsize / sizeof(struct ext2_gd);
        else
                descpb = fs->e2fs_bsize / E2FS_REV0_GD_SIZE;

        cg = descpb * number;

        if (ext2_cg_has_sb(fs, cg))
                has_super = 1;

        return (has_super + cg * (e4fs_daddr_t)EXT2_BLOCKS_PER_GROUP(fs) +
            le32toh(fs->e2fs->e2fs_first_dblock));
}

static int
ext2_cg_validate(struct m_ext2fs *fs)
{
        uint64_t b_bitmap;
        uint64_t i_bitmap;
        uint64_t i_tables;
        uint64_t first_block, last_block, last_cg_block;
        struct ext2_gd *gd;
        unsigned int i, cg_count;

        first_block = le32toh(fs->e2fs->e2fs_first_dblock);
        last_cg_block = ext2_cg_number_gdb(fs, 0);
        cg_count = fs->e2fs_gcount;

        for (i = 0; i < fs->e2fs_gcount; i++) {
                gd = &fs->e2fs_gd[i];

                if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_FLEX_BG) ||
                    i == fs->e2fs_gcount - 1) {
                        last_block = fs->e2fs_bcount - 1;
                } else {
                        last_block = first_block +
                            (EXT2_BLOCKS_PER_GROUP(fs) - 1);
                }

                if ((cg_count == fs->e2fs_gcount) &&
                    !(le16toh(gd->ext4bgd_flags) & EXT2_BG_INODE_ZEROED))
                        cg_count = i;

                b_bitmap = e2fs_gd_get_b_bitmap(gd);
                if (b_bitmap == 0) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "block bitmap is zero", i);
                        return (EINVAL);
                }
                if (b_bitmap <= last_cg_block) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "block bitmap overlaps gds", i);
                        return (EINVAL);
                }
                if (b_bitmap < first_block || b_bitmap > last_block) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "block bitmap not in group", i);
                        return (EINVAL);
                }

                i_bitmap = e2fs_gd_get_i_bitmap(gd);
                if (i_bitmap == 0) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "inode bitmap is zero", i);
                        return (EINVAL);
                }
                if (i_bitmap <= last_cg_block) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "inode bitmap overlaps gds", i);
                        return (EINVAL);
                }
                if (i_bitmap < first_block || i_bitmap > last_block) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "inode bitmap not in group blk", i);
                        return (EINVAL);
                }

                i_tables = e2fs_gd_get_i_tables(gd);
                if (i_tables == 0) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "inode table is zero", i);
                        return (EINVAL);
                }
                if (i_tables <= last_cg_block) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "inode tables overlaps gds", i);
                        return (EINVAL);
                }
                if (i_tables < first_block ||
                    i_tables + fs->e2fs_itpg - 1 > last_block) {
                        SDT_PROBE2(ext2fs, , vfsops, ext2_cg_validate_error,
                            "inode tables not in group blk", i);
                        return (EINVAL);
                }

                if (!EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_FLEX_BG))
                        first_block += EXT2_BLOCKS_PER_GROUP(fs);
        }

        return (0);
}

/*
 * This computes the fields of the m_ext2fs structure from the
 * data in the ext2fs structure read in.
 */
static int
ext2_compute_sb_data(struct vnode *devvp, struct ext2fs *es,
    struct m_ext2fs *fs)
{
        struct buf *bp;
        uint32_t e2fs_descpb, e2fs_gdbcount_alloc;
        int i, j;
        int g_count = 0;
        int error;

        /* Check checksum features */
        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_GDT_CSUM) &&
            EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM)) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "incorrect checksum features combination");
                return (EINVAL);
        }

        /* Precompute checksum seed for all metadata */
        ext2_sb_csum_set_seed(fs);

        /* Verify sb csum if possible */
        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM)) {
                error = ext2_sb_csum_verify(fs);
                if (error) {
                        return (error);
                }
        }

        /* Check for block size = 1K|2K|4K */
        if (le32toh(es->e2fs_log_bsize) > 2) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "bad block size");
                return (EINVAL);
        }

        fs->e2fs_bshift = EXT2_MIN_BLOCK_LOG_SIZE + le32toh(es->e2fs_log_bsize);
        fs->e2fs_bsize = 1U << fs->e2fs_bshift;
        fs->e2fs_fsbtodb = le32toh(es->e2fs_log_bsize) + 1;
        fs->e2fs_qbmask = fs->e2fs_bsize - 1;

        /* Check for fragment size */
        if (le32toh(es->e2fs_log_fsize) >
            (EXT2_MAX_FRAG_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "invalid log cluster size");
                return (EINVAL);
        }

        fs->e2fs_fsize = EXT2_MIN_FRAG_SIZE << le32toh(es->e2fs_log_fsize);
        if (fs->e2fs_fsize != fs->e2fs_bsize) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "fragment size != block size");
                return (EINVAL);
        }

        fs->e2fs_fpb = fs->e2fs_bsize / fs->e2fs_fsize;

        /* Check reserved gdt blocks for future filesystem expansion */
        if (le16toh(es->e2fs_reserved_ngdb) > (fs->e2fs_bsize / 4)) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "number of reserved GDT blocks too large");
                return (EINVAL);
        }

        if (le32toh(es->e2fs_rev) == E2FS_REV0) {
                fs->e2fs_isize = E2FS_REV0_INODE_SIZE;
        } else {
                fs->e2fs_isize = le16toh(es->e2fs_inode_size);

                /*
                 * Check first ino.
                 */
                if (le32toh(es->e2fs_first_ino) < EXT2_FIRSTINO) {
                        SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                            "invalid first ino");
                        return (EINVAL);
                }

                /*
                 * Simple sanity check for superblock inode size value.
                 */
                if (EXT2_INODE_SIZE(fs) < E2FS_REV0_INODE_SIZE ||
                    EXT2_INODE_SIZE(fs) > fs->e2fs_bsize ||
                    (fs->e2fs_isize & (fs->e2fs_isize - 1)) != 0) {
                        SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                            "invalid inode size");
                        return (EINVAL);
                }
        }

        /* Check group descriptors */
        if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT) &&
            le16toh(es->e3fs_desc_size) != E2FS_64BIT_GD_SIZE) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "unsupported 64bit descriptor size");
                return (EINVAL);
        }

        fs->e2fs_bpg = le32toh(es->e2fs_bpg);
        fs->e2fs_fpg = le32toh(es->e2fs_fpg);
        if (fs->e2fs_bpg == 0 || fs->e2fs_fpg == 0) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "zero blocks/fragments per group");
                return (EINVAL);
        } else if (fs->e2fs_bpg != fs->e2fs_fpg) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "blocks per group not equal fragments per group");
                return (EINVAL);
        }

        if (fs->e2fs_bpg != fs->e2fs_bsize * 8) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "non-standard group size unsupported");
                return (EINVAL);
        }

        fs->e2fs_ipb = fs->e2fs_bsize / EXT2_INODE_SIZE(fs);
        if (fs->e2fs_ipb == 0 ||
            fs->e2fs_ipb > fs->e2fs_bsize / E2FS_REV0_INODE_SIZE) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "bad inodes per block size");
                return (EINVAL);
        }

        fs->e2fs_ipg = le32toh(es->e2fs_ipg);
        if (fs->e2fs_ipg < fs->e2fs_ipb || fs->e2fs_ipg >  fs->e2fs_bsize * 8) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "invalid inodes per group");
                return (EINVAL);
        }

        fs->e2fs_itpg = fs->e2fs_ipg / fs->e2fs_ipb;

        fs->e2fs_bcount = le32toh(es->e2fs_bcount);
        fs->e2fs_rbcount = le32toh(es->e2fs_rbcount);
        fs->e2fs_fbcount = le32toh(es->e2fs_fbcount);
        if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT)) {
                fs->e2fs_bcount |= (uint64_t)(le32toh(es->e4fs_bcount_hi)) << 32;
                fs->e2fs_rbcount |= (uint64_t)(le32toh(es->e4fs_rbcount_hi)) << 32;
                fs->e2fs_fbcount |= (uint64_t)(le32toh(es->e4fs_fbcount_hi)) << 32;
        }
        if (fs->e2fs_rbcount > fs->e2fs_bcount ||
            fs->e2fs_fbcount > fs->e2fs_bcount) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "invalid block count");
                return (EINVAL);
        }

        fs->e2fs_ficount = le32toh(es->e2fs_ficount);
        if (fs->e2fs_ficount > le32toh(es->e2fs_icount)) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "invalid number of free inodes");
                return (EINVAL);
        }

        if (le32toh(es->e2fs_first_dblock) != (fs->e2fs_bsize > 1024 ? 0 : 1) ||
            le32toh(es->e2fs_first_dblock) >= fs->e2fs_bcount) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "first data block out of range");
                return (EINVAL);
        }

        fs->e2fs_gcount = howmany(fs->e2fs_bcount -
            le32toh(es->e2fs_first_dblock), EXT2_BLOCKS_PER_GROUP(fs));
        if (fs->e2fs_gcount > ((uint64_t)1 << 32) - EXT2_DESCS_PER_BLOCK(fs)) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "groups count too large");
                return (EINVAL);
        }

        /* Check for extra isize in big inodes. */
        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_EXTRA_ISIZE) &&
            EXT2_INODE_SIZE(fs) < sizeof(struct ext2fs_dinode)) {
                SDT_PROBE1(ext2fs, , vfsops, ext2_compute_sb_data_error,
                    "no space for extra inode timestamps");
                return (EINVAL);
        }

        /* s_resuid / s_resgid ? */

        if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT)) {
                e2fs_descpb = fs->e2fs_bsize / E2FS_64BIT_GD_SIZE;
                e2fs_gdbcount_alloc = howmany(fs->e2fs_gcount, e2fs_descpb);
        } else {
                e2fs_descpb = fs->e2fs_bsize / E2FS_REV0_GD_SIZE;
                e2fs_gdbcount_alloc = howmany(fs->e2fs_gcount,
                    fs->e2fs_bsize / sizeof(struct ext2_gd));
        }
        fs->e2fs_gdbcount = howmany(fs->e2fs_gcount, e2fs_descpb);
        fs->e2fs_gd = malloc(e2fs_gdbcount_alloc * fs->e2fs_bsize,
            M_EXT2MNT, M_WAITOK | M_ZERO);
        fs->e2fs_contigdirs = malloc(fs->e2fs_gcount *
            sizeof(*fs->e2fs_contigdirs), M_EXT2MNT, M_WAITOK | M_ZERO);

        for (i = 0; i < fs->e2fs_gdbcount; i++) {
                error = bread(devvp,
                    fsbtodb(fs, ext2_cg_location(fs, i)),
                    fs->e2fs_bsize, NOCRED, &bp);
                if (error) {
                        /*
                         * fs->e2fs_gd and fs->e2fs_contigdirs
                         * will be freed later by the caller,
                         * because this function could be called from
                         * MNT_UPDATE path.
                         */
                        return (error);
                }
                if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT)) {
                        memcpy(&fs->e2fs_gd[
                            i * fs->e2fs_bsize / sizeof(struct ext2_gd)],
                            bp->b_data, fs->e2fs_bsize);
                } else {
                        for (j = 0; j < e2fs_descpb &&
                            g_count < fs->e2fs_gcount; j++, g_count++)
                                memcpy(&fs->e2fs_gd[g_count],
                                    bp->b_data + j * E2FS_REV0_GD_SIZE,
                                    E2FS_REV0_GD_SIZE);
                }
                brelse(bp);
                bp = NULL;
        }

        /* Validate cgs consistency */
        error = ext2_cg_validate(fs);
        if (error)
                return (error);

        /* Verfy cgs csum */
        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_GDT_CSUM) ||
            EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM)) {
                error = ext2_gd_csum_verify(fs, devvp->v_rdev);
                if (error)
                        return (error);
        }
        /* Initialization for the ext2 Orlov allocator variant. */
        fs->e2fs_total_dir = 0;
        for (i = 0; i < fs->e2fs_gcount; i++)
                fs->e2fs_total_dir += e2fs_gd_get_ndirs(&fs->e2fs_gd[i]);

        if (le32toh(es->e2fs_rev) == E2FS_REV0 ||
            !EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_LARGEFILE))
                fs->e2fs_maxfilesize = 0x7fffffff;
        else {
                fs->e2fs_maxfilesize = 0xffffffffffff;
                if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_HUGE_FILE))
                        fs->e2fs_maxfilesize = 0x7fffffffffffffff;
        }
        if (le32toh(es->e4fs_flags) & E2FS_UNSIGNED_HASH) {
                fs->e2fs_uhash = 3;
        } else if ((le32toh(es->e4fs_flags) & E2FS_SIGNED_HASH) == 0) {
#ifdef __CHAR_UNSIGNED__
                es->e4fs_flags = htole32(le32toh(es->e4fs_flags) | E2FS_UNSIGNED_HASH);
                fs->e2fs_uhash = 3;
#else
                es->e4fs_flags = htole32(le32toh(es->e4fs_flags) | E2FS_SIGNED_HASH);
#endif
        }
        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
                error = ext2_sb_csum_verify(fs);

        return (error);
}

/*
 * Reload all incore data for a filesystem (used after running fsck on
 * the root filesystem and finding things to fix). The filesystem must
 * be mounted read-only.
 *
 * Things to do to update the mount:
 *      1) invalidate all cached meta-data.
 *      2) re-read superblock from disk.
 *      3) invalidate all cluster summary information.
 *      4) invalidate all inactive vnodes.
 *      5) invalidate all cached file data.
 *      6) re-read inode data for all active vnodes.
 * XXX we are missing some steps, in particular # 3, this has to be reviewed.
 */
static int
ext2_reload(struct mount *mp, struct thread *td)
{
        struct vnode *vp, *mvp, *devvp;
        struct inode *ip;
        struct buf *bp;
        struct ext2fs *es;
        struct m_ext2fs *fs;
        struct csum *sump;
        int error, i;
        int32_t *lp;

        if ((mp->mnt_flag & MNT_RDONLY) == 0)
                return (EINVAL);
        /*
         * Step 1: invalidate all cached meta-data.
         */
        devvp = VFSTOEXT2(mp)->um_devvp;
        vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
        if (vinvalbuf(devvp, 0, 0, 0) != 0)
                panic("ext2_reload: dirty1");
        VOP_UNLOCK(devvp);

        /*
         * Step 2: re-read superblock from disk.
         * constants have been adjusted for ext2
         */
        if ((error = bread(devvp, SBLOCK, SBLOCKBLKSIZE, NOCRED, &bp)) != 0)
                return (error);
        es = (struct ext2fs *)((char *)bp->b_data + SBLOCKOFFSET);
        if (ext2_check_sb_compat(es, devvp->v_rdev, 0) != 0) {
                brelse(bp);
                return (EIO);           /* XXX needs translation */
        }
        fs = VFSTOEXT2(mp)->um_e2fs;
        bcopy(bp->b_data, fs->e2fs, sizeof(struct ext2fs));

        if ((error = ext2_compute_sb_data(devvp, es, fs)) != 0) {
                brelse(bp);
                return (error);
        }

        brelse(bp);

        /*
         * Step 3: invalidate all cluster summary information.
         */
        if (fs->e2fs_contigsumsize > 0) {
                lp = fs->e2fs_maxcluster;
                sump = fs->e2fs_clustersum;
                for (i = 0; i < fs->e2fs_gcount; i++, sump++) {
                        *lp++ = fs->e2fs_contigsumsize;
                        sump->cs_init = 0;
                        bzero(sump->cs_sum, fs->e2fs_contigsumsize + 1);
                }
        }

loop:
        MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
                /*
                 * Step 4: invalidate all cached file data.
                 */
                if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK)) {
                        MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
                        goto loop;
                }
                if (vinvalbuf(vp, 0, 0, 0))
                        panic("ext2_reload: dirty2");

                /*
                 * Step 5: re-read inode data for all active vnodes.
                 */
                ip = VTOI(vp);
                error = bread(devvp, fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
                    (int)fs->e2fs_bsize, NOCRED, &bp);
                if (error) {
                        vput(vp);
                        MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
                        return (error);
                }

                error = ext2_ei2i((struct ext2fs_dinode *)((char *)bp->b_data +
                    EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ip->i_number)), ip);

                brelse(bp);
                vput(vp);

                if (error) {
                        MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
                        return (error);
                }
        }
        return (0);
}

/*
 * Common code for mount and mountroot.
 */
static int
ext2_mountfs(struct vnode *devvp, struct mount *mp)
{
        struct ext2mount *ump;
        struct buf *bp;
        struct m_ext2fs *fs;
        struct ext2fs *es;
        struct cdev *dev = devvp->v_rdev;
        struct g_consumer *cp;
        struct bufobj *bo;
        struct csum *sump;
        int error;
        int ronly;
        int i;
        u_long size;
        int32_t *lp;
        int32_t e2fs_maxcontig;

        bp = NULL;
        ump = NULL;

        ronly = vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0);
        /* XXX: use VOP_ACESS to check FS perms */
        g_topology_lock();
        error = g_vfs_open(devvp, &cp, "ext2fs", ronly ? 0 : 1);
        g_topology_unlock();
        VOP_UNLOCK(devvp);
        if (error)
                return (error);

        if (PAGE_SIZE != SBLOCKBLKSIZE) {
                printf("WARNING: Unsupported page size %d\n", PAGE_SIZE);
                error = EINVAL;
                goto out;
        }
        if (cp->provider->sectorsize > PAGE_SIZE) {
                printf("WARNING: Device sectorsize(%d) is more than %d\n",
                    cp->provider->sectorsize, PAGE_SIZE);
                error = EINVAL;
                goto out;
        }

        bo = &devvp->v_bufobj;
        bo->bo_private = cp;
        bo->bo_ops = g_vfs_bufops;
        if (devvp->v_rdev->si_iosize_max != 0)
                mp->mnt_iosize_max = devvp->v_rdev->si_iosize_max;
        if (mp->mnt_iosize_max > maxphys)
                mp->mnt_iosize_max = maxphys;
        if ((error = bread(devvp, SBLOCK, SBLOCKBLKSIZE, NOCRED, &bp)) != 0)
                goto out;
        es = (struct ext2fs *)((char *)bp->b_data + SBLOCKOFFSET);
        if (ext2_check_sb_compat(es, dev, ronly) != 0) {
                error = EINVAL;         /* XXX needs translation */
                goto out;
        }
        if ((le16toh(es->e2fs_state) & E2FS_ISCLEAN) == 0 ||
            (le16toh(es->e2fs_state) & E2FS_ERRORS)) {
                if (ronly || (mp->mnt_flag & MNT_FORCE)) {
                        printf(
"WARNING: Filesystem was not properly dismounted\n");
                } else {
                        printf(
"WARNING: R/W mount denied.  Filesystem is not clean - run fsck\n");
                        error = EPERM;
                        goto out;
                }
        }
        ump = malloc(sizeof(*ump), M_EXT2MNT, M_WAITOK | M_ZERO);

        /*
         * I don't know whether this is the right strategy. Note that
         * we dynamically allocate both an m_ext2fs and an ext2fs
         * while Linux keeps the super block in a locked buffer.
         */
        ump->um_e2fs = malloc(sizeof(struct m_ext2fs),
            M_EXT2MNT, M_WAITOK | M_ZERO);
        ump->um_e2fs->e2fs = malloc(sizeof(struct ext2fs),
            M_EXT2MNT, M_WAITOK);
        mtx_init(EXT2_MTX(ump), "EXT2FS", "EXT2FS Lock", MTX_DEF);
        bcopy(es, ump->um_e2fs->e2fs, (u_int)sizeof(struct ext2fs));
        if ((error = ext2_compute_sb_data(devvp, ump->um_e2fs->e2fs, ump->um_e2fs)))
                goto out;

        /*
         * Calculate the maximum contiguous blocks and size of cluster summary
         * array.  In FFS this is done by newfs; however, the superblock
         * in ext2fs doesn't have these variables, so we can calculate
         * them here.
         */
        e2fs_maxcontig = MAX(1, maxphys / ump->um_e2fs->e2fs_bsize);
        ump->um_e2fs->e2fs_contigsumsize = MIN(e2fs_maxcontig, EXT2_MAXCONTIG);
        ump->um_e2fs->e2fs_maxsymlinklen = EXT2_MAXSYMLINKLEN;
        if (ump->um_e2fs->e2fs_contigsumsize > 0) {
                size = ump->um_e2fs->e2fs_gcount * sizeof(int32_t);
                ump->um_e2fs->e2fs_maxcluster = malloc(size, M_EXT2MNT, M_WAITOK);
                size = ump->um_e2fs->e2fs_gcount * sizeof(struct csum);
                ump->um_e2fs->e2fs_clustersum = malloc(size, M_EXT2MNT, M_WAITOK);
                lp = ump->um_e2fs->e2fs_maxcluster;
                sump = ump->um_e2fs->e2fs_clustersum;
                for (i = 0; i < ump->um_e2fs->e2fs_gcount; i++, sump++) {
                        *lp++ = ump->um_e2fs->e2fs_contigsumsize;
                        sump->cs_init = 0;
                        sump->cs_sum = malloc((ump->um_e2fs->e2fs_contigsumsize + 1) *
                            sizeof(int32_t), M_EXT2MNT, M_WAITOK | M_ZERO);
                }
        }

        brelse(bp);
        bp = NULL;
        fs = ump->um_e2fs;
        fs->e2fs_ronly = ronly; /* ronly is set according to mnt_flags */

        /*
         * If the fs is not mounted read-only, make sure the super block is
         * always written back on a sync().
         */
        fs->e2fs_wasvalid = le16toh(fs->e2fs->e2fs_state) & E2FS_ISCLEAN ? 1 : 0;
        if (ronly == 0) {
                fs->e2fs_fmod = 1;      /* mark it modified and set fs invalid */
                fs->e2fs->e2fs_state =
                    htole16(le16toh(fs->e2fs->e2fs_state) & ~E2FS_ISCLEAN);
        }
        mp->mnt_data = ump;
        mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
        mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
        MNT_ILOCK(mp);
        mp->mnt_flag |= MNT_LOCAL;
        MNT_IUNLOCK(mp);
        ump->um_mountp = mp;
        ump->um_dev = dev;
        ump->um_devvp = devvp;
        ump->um_bo = &devvp->v_bufobj;
        ump->um_cp = cp;

        /*
         * Setting those two parameters allowed us to use
         * ufs_bmap w/o changse!
         */
        ump->um_nindir = EXT2_ADDR_PER_BLOCK(fs);
        ump->um_bptrtodb = le32toh(fs->e2fs->e2fs_log_bsize) + 1;
        ump->um_seqinc = EXT2_FRAGS_PER_BLOCK(fs);
        if (ronly == 0)
                ext2_sbupdate(ump, MNT_WAIT);
        /*
         * Initialize filesystem stat information in mount struct.
         */
        MNT_ILOCK(mp);
        mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
            MNTK_USES_BCACHE;
        MNT_IUNLOCK(mp);
        return (0);
out:
        if (bp)
                brelse(bp);
        if (cp != NULL) {
                g_topology_lock();
                g_vfs_close(cp);
                g_topology_unlock();
        }
        if (ump) {
                mtx_destroy(EXT2_MTX(ump));
                free(ump->um_e2fs->e2fs_gd, M_EXT2MNT);
                free(ump->um_e2fs->e2fs_contigdirs, M_EXT2MNT);
                free(ump->um_e2fs->e2fs, M_EXT2MNT);
                free(ump->um_e2fs, M_EXT2MNT);
                free(ump, M_EXT2MNT);
                mp->mnt_data = NULL;
        }
        return (error);
}

/*
 * Unmount system call.
 */
static int
ext2_unmount(struct mount *mp, int mntflags)
{
        struct ext2mount *ump;
        struct m_ext2fs *fs;
        struct csum *sump;
        int error, flags, i, ronly;

        flags = 0;
        if (mntflags & MNT_FORCE) {
                if (mp->mnt_flag & MNT_ROOTFS)
                        return (EINVAL);
                flags |= FORCECLOSE;
        }
        if ((error = ext2_flushfiles(mp, flags, curthread)) != 0)
                return (error);
        ump = VFSTOEXT2(mp);
        fs = ump->um_e2fs;
        ronly = fs->e2fs_ronly;
        if (ronly == 0 && ext2_cgupdate(ump, MNT_WAIT) == 0) {
                if (fs->e2fs_wasvalid)
                        fs->e2fs->e2fs_state =
                            htole16(le16toh(fs->e2fs->e2fs_state) | E2FS_ISCLEAN);
                ext2_sbupdate(ump, MNT_WAIT);
        }

        g_topology_lock();
        g_vfs_close(ump->um_cp);
        g_topology_unlock();
        vrele(ump->um_devvp);
        sump = fs->e2fs_clustersum;
        for (i = 0; i < fs->e2fs_gcount; i++, sump++)
                free(sump->cs_sum, M_EXT2MNT);
        free(fs->e2fs_clustersum, M_EXT2MNT);
        free(fs->e2fs_maxcluster, M_EXT2MNT);
        free(fs->e2fs_gd, M_EXT2MNT);
        free(fs->e2fs_contigdirs, M_EXT2MNT);
        free(fs->e2fs, M_EXT2MNT);
        free(fs, M_EXT2MNT);
        free(ump, M_EXT2MNT);
        mp->mnt_data = NULL;
        return (error);
}

/*
 * Flush out all the files in a filesystem.
 */
static int
ext2_flushfiles(struct mount *mp, int flags, struct thread *td)
{
        int error;

        error = vflush(mp, 0, flags, td);
        return (error);
}

/*
 * Get filesystem statistics.
 */
int
ext2_statfs(struct mount *mp, struct statfs *sbp)
{
        struct ext2mount *ump;
        struct m_ext2fs *fs;
        uint32_t overhead, overhead_per_group, ngdb;
        int i, ngroups;

        ump = VFSTOEXT2(mp);
        fs = ump->um_e2fs;
        if (le16toh(fs->e2fs->e2fs_magic) != E2FS_MAGIC)
                panic("ext2_statfs");

        /*
         * Compute the overhead (FS structures)
         */
        overhead_per_group =
            1 /* block bitmap */ +
            1 /* inode bitmap */ +
            fs->e2fs_itpg;
        overhead = le32toh(fs->e2fs->e2fs_first_dblock) +
            fs->e2fs_gcount * overhead_per_group;
        if (le32toh(fs->e2fs->e2fs_rev) > E2FS_REV0 &&
            le32toh(fs->e2fs->e2fs_features_rocompat) & EXT2F_ROCOMPAT_SPARSESUPER) {
                for (i = 0, ngroups = 0; i < fs->e2fs_gcount; i++) {
                        if (ext2_cg_has_sb(fs, i))
                                ngroups++;
                }
        } else {
                ngroups = fs->e2fs_gcount;
        }
        ngdb = fs->e2fs_gdbcount;
        if (le32toh(fs->e2fs->e2fs_rev) > E2FS_REV0 &&
            le32toh(fs->e2fs->e2fs_features_compat) & EXT2F_COMPAT_RESIZE)
                ngdb += le16toh(fs->e2fs->e2fs_reserved_ngdb);
        overhead += ngroups * (1 /* superblock */ + ngdb);

        sbp->f_bsize = EXT2_FRAG_SIZE(fs);
        sbp->f_iosize = EXT2_BLOCK_SIZE(fs);
        sbp->f_blocks = fs->e2fs_bcount - overhead;
        sbp->f_bfree = fs->e2fs_fbcount;
        sbp->f_bavail = sbp->f_bfree - fs->e2fs_rbcount;
        sbp->f_files = le32toh(fs->e2fs->e2fs_icount);
        sbp->f_ffree = fs->e2fs_ficount;
        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'.
 */
static int
ext2_sync(struct mount *mp, int waitfor)
{
        struct vnode *mvp, *vp;
        struct thread *td;
        struct inode *ip;
        struct ext2mount *ump = VFSTOEXT2(mp);
        struct m_ext2fs *fs;
        int error, allerror = 0;

        td = curthread;
        fs = ump->um_e2fs;
        if (fs->e2fs_fmod != 0 && fs->e2fs_ronly != 0) {                /* XXX */
                panic("ext2_sync: rofs mod fs=%s", fs->e2fs_fsmnt);
        }

        /*
         * Write back each (modified) inode.
         */
loop:
        MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
                if (vp->v_type == VNON) {
                        VI_UNLOCK(vp);
                        continue;
                }
                ip = VTOI(vp);
                if ((ip->i_flag &
                    (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE)) == 0 &&
                    (vp->v_bufobj.bo_dirty.bv_cnt == 0 ||
                    waitfor == MNT_LAZY)) {
                        VI_UNLOCK(vp);
                        continue;
                }
                error = vget(vp, LK_EXCLUSIVE | LK_NOWAIT | LK_INTERLOCK);
                if (error) {
                        if (error == ENOENT) {
                                MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
                                goto loop;
                        }
                        continue;
                }
                if ((error = VOP_FSYNC(vp, waitfor, td)) != 0)
                        allerror = error;
                vput(vp);
        }

        /*
         * Force stale filesystem control information to be flushed.
         */
        if (waitfor != MNT_LAZY) {
                vn_lock(ump->um_devvp, LK_EXCLUSIVE | LK_RETRY);
                if ((error = VOP_FSYNC(ump->um_devvp, waitfor, td)) != 0)
                        allerror = error;
                VOP_UNLOCK(ump->um_devvp);
        }

        /*
         * Write back modified superblock.
         */
        if (fs->e2fs_fmod != 0) {
                fs->e2fs_fmod = 0;
                fs->e2fs->e2fs_wtime = htole32(time_second);
                if ((error = ext2_cgupdate(ump, waitfor)) != 0)
                        allerror = error;
        }
        return (allerror);
}

/*
 * Look up an EXT2FS dinode number to find its incore vnode, otherwise read it
 * in from disk.  If it is in core, wait for the lock bit to clear, then
 * return the inode locked.  Detection and handling of mount points must be
 * done by the calling routine.
 */
static int
ext2_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
{
        struct m_ext2fs *fs;
        struct inode *ip;
        struct ext2mount *ump;
        struct buf *bp;
        struct vnode *vp;
        struct thread *td;
        unsigned int i, used_blocks;
        int error;

        td = curthread;
        error = vfs_hash_get(mp, ino, flags, td, vpp, NULL, NULL);
        if (error || *vpp != NULL)
                return (error);

        ump = VFSTOEXT2(mp);
        ip = malloc(sizeof(struct inode), M_EXT2NODE, M_WAITOK | M_ZERO);

        /* Allocate a new vnode/inode. */
        if ((error = getnewvnode("ext2fs", mp, &ext2_vnodeops, &vp)) != 0) {
                *vpp = NULL;
                free(ip, M_EXT2NODE);
                return (error);
        }
        vp->v_data = ip;
        ip->i_vnode = vp;
        ip->i_e2fs = fs = ump->um_e2fs;
        ip->i_ump = ump;
        ip->i_number = ino;
        cluster_init_vn(&ip->i_clusterw);

        lockmgr(vp->v_vnlock, LK_EXCLUSIVE, NULL);
        error = insmntque(vp, mp);
        if (error != 0) {
                free(ip, M_EXT2NODE);
                *vpp = NULL;
                return (error);
        }
        error = vfs_hash_insert(vp, ino, flags, td, vpp, NULL, NULL);
        if (error || *vpp != NULL)
                return (error);

        /* Read in the disk contents for the inode, copy into the inode. */
        if ((error = bread(ump->um_devvp, fsbtodb(fs, ino_to_fsba(fs, ino)),
            (int)fs->e2fs_bsize, NOCRED, &bp)) != 0) {
                /*
                 * 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().
                 */
                brelse(bp);
                vput(vp);
                *vpp = NULL;
                return (error);
        }
        /* convert ext2 inode to dinode */
        error = ext2_ei2i((struct ext2fs_dinode *)((char *)bp->b_data +
            EXT2_INODE_SIZE(fs) * ino_to_fsbo(fs, ino)), ip);
        if (error) {
                brelse(bp);
                vput(vp);
                *vpp = NULL;
                return (error);
        }
        ip->i_block_group = ino_to_cg(fs, ino);
        ip->i_next_alloc_block = 0;
        ip->i_next_alloc_goal = 0;

        /*
         * Now we want to make sure that block pointers for unused
         * blocks are zeroed out - ext2_balloc depends on this
         * although for regular files and directories only
         *
         * If IN_E4EXTENTS is enabled, unused blocks are not zeroed
         * out because we could corrupt the extent tree.
         */
        if (!(ip->i_flag & IN_E4EXTENTS) &&
            (S_ISDIR(ip->i_mode) || S_ISREG(ip->i_mode))) {
                used_blocks = howmany(ip->i_size, fs->e2fs_bsize);
                for (i = used_blocks; i < EXT2_NDIR_BLOCKS; i++)
                        ip->i_db[i] = 0;
        }

        bqrelse(bp);

#ifdef EXT2FS_PRINT_EXTENTS
        ext2_print_inode(ip);
        error = ext4_ext_walk(ip);
        if (error) {
                vput(vp);
                *vpp = NULL;
                return (error);
        }
#endif

        /*
         * Initialize the vnode from the inode, check for aliases.
         * Note that the underlying vnode may have changed.
         */
        if ((error = ext2_vinit(mp, &ext2_fifoops, &vp)) != 0) {
                vput(vp);
                *vpp = NULL;
                return (error);
        }

        /*
         * Finish inode initialization.
         */

        vn_set_state(vp, VSTATE_CONSTRUCTED);
        *vpp = vp;
        return (0);
}

/*
 * File handle to vnode
 *
 * Have to be really careful about stale file handles:
 * - check that the inode number is valid
 * - call ext2_vget() to get the locked inode
 * - check for an unallocated inode (i_mode == 0)
 * - check that the given client host has export rights and return
 *   those rights via. exflagsp and credanonp
 */
static int
ext2_fhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
{
        struct inode *ip;
        struct ufid *ufhp;
        struct vnode *nvp;
        struct m_ext2fs *fs;
        int error;

        ufhp = (struct ufid *)fhp;
        fs = VFSTOEXT2(mp)->um_e2fs;
        if (ufhp->ufid_ino < EXT2_ROOTINO ||
            ufhp->ufid_ino > fs->e2fs_gcount * fs->e2fs_ipg)
                return (ESTALE);

        error = VFS_VGET(mp, ufhp->ufid_ino, LK_EXCLUSIVE, &nvp);
        if (error) {
                *vpp = NULL;
                return (error);
        }
        ip = VTOI(nvp);
        if (ip->i_mode == 0 ||
            ip->i_gen != ufhp->ufid_gen || ip->i_nlink <= 0) {
                vput(nvp);
                *vpp = NULL;
                return (ESTALE);
        }
        *vpp = nvp;
        vnode_create_vobject(*vpp, ip->i_size, curthread);
        return (0);
}

/*
 * Write a superblock and associated information back to disk.
 */
static int
ext2_sbupdate(struct ext2mount *mp, int waitfor)
{
        struct m_ext2fs *fs = mp->um_e2fs;
        struct ext2fs *es = fs->e2fs;
        struct buf *bp;
        int error = 0;

        es->e2fs_bcount = htole32(fs->e2fs_bcount & 0xffffffff);
        es->e2fs_rbcount = htole32(fs->e2fs_rbcount & 0xffffffff);
        es->e2fs_fbcount = htole32(fs->e2fs_fbcount & 0xffffffff);
        if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT)) {
                es->e4fs_bcount_hi = htole32(fs->e2fs_bcount >> 32);
                es->e4fs_rbcount_hi = htole32(fs->e2fs_rbcount >> 32);
                es->e4fs_fbcount_hi = htole32(fs->e2fs_fbcount >> 32);
        }

        es->e2fs_ficount = htole32(fs->e2fs_ficount);

        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
                ext2_sb_csum_set(fs);

        error = bread(mp->um_devvp, SBLOCK, SBLOCKBLKSIZE, NOCRED, &bp);
        if (error != 0)
                return (error);

        memcpy((char *)bp->b_data + SBLOCKOFFSET, (caddr_t)es,
            (u_int)sizeof(struct ext2fs));
        if (waitfor == MNT_WAIT)
                error = bwrite(bp);
        else
                bawrite(bp);

        /*
         * The buffers for group descriptors, inode bitmaps and block bitmaps
         * are not busy at this point and are (hopefully) written by the
         * usual sync mechanism. No need to write them here.
         */
        return (error);
}
int
ext2_cgupdate(struct ext2mount *mp, int waitfor)
{
        struct m_ext2fs *fs = mp->um_e2fs;
        struct buf *bp;
        int i, j, g_count = 0, error = 0, allerror = 0;

        allerror = ext2_sbupdate(mp, waitfor);

        /* Update gd csums */
        if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_GDT_CSUM) ||
            EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM))
                ext2_gd_csum_set(fs);

        for (i = 0; i < fs->e2fs_gdbcount; i++) {
                bp = getblk(mp->um_devvp, fsbtodb(fs,
                    ext2_cg_location(fs, i)),
                    fs->e2fs_bsize, 0, 0, 0);
                if (EXT2_HAS_INCOMPAT_FEATURE(fs, EXT2F_INCOMPAT_64BIT)) {
                        memcpy(bp->b_data, &fs->e2fs_gd[
                            i * fs->e2fs_bsize / sizeof(struct ext2_gd)],
                            fs->e2fs_bsize);
                } else {
                        for (j = 0; j < fs->e2fs_bsize / E2FS_REV0_GD_SIZE &&
                            g_count < fs->e2fs_gcount; j++, g_count++)
                                memcpy(bp->b_data + j * E2FS_REV0_GD_SIZE,
                                    &fs->e2fs_gd[g_count], E2FS_REV0_GD_SIZE);
                }
                if (waitfor == MNT_WAIT)
                        error = bwrite(bp);
                else
                        bawrite(bp);
        }

        if (!allerror && error)
                allerror = error;
        return (allerror);
}

/*
 * Return the root of a filesystem.
 */
static int
ext2_root(struct mount *mp, int flags, struct vnode **vpp)
{
        struct vnode *nvp;
        int error;

        error = VFS_VGET(mp, EXT2_ROOTINO, LK_EXCLUSIVE, &nvp);
        if (error)
                return (error);
        *vpp = nvp;
        return (0);
}