/*-
 *  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.
 *
 *	@(#)ffs_vfsops.c	8.8 (Berkeley) 4/18/94
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/caps.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/bio.h>
#include <sys/buf2.h>
#include <sys/conf.h>
#include <sys/endian.h>
#include <sys/fcntl.h>
#include <sys/malloc.h>
#include <sys/stat.h>
#include <sys/mutex2.h>
#include <sys/nlookup.h>

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

#include <vfs/ext2fs/ext2fs.h>
#include <vfs/ext2fs/ext2_dinode.h>
#include <vfs/ext2fs/ext2_extern.h>
#include <vfs/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);
static int	ext2_mountfs(struct vnode *, struct mount *);
static int	ext2_reload(struct mount *mp);
static int	ext2_sbupdate(struct ext2mount *, int);
static int	ext2_cgupdate(struct ext2mount *, int);
static int	ext2_init(struct vfsconf *);
static int	ext2_uninit(struct vfsconf *);
static vfs_unmount_t		ext2_unmount;
static vfs_root_t		ext2_root;
static vfs_statfs_t		ext2_statfs;
static vfs_statvfs_t		ext2_statvfs;
static vfs_sync_t		ext2_sync;
static vfs_vget_t		ext2_vget;
static vfs_fhtovp_t		ext2_fhtovp;
static vfs_vptofh_t		ext2_vptofh;
static vfs_checkexp_t		ext2_check_export;
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_flags =		0,
	.vfs_mount =		ext2_mount,
	.vfs_unmount =		ext2_unmount,
	.vfs_root =		ext2_root,	/* root inode via vget */
	.vfs_statfs =		ext2_statfs,
	.vfs_statvfs =		ext2_statvfs,
	.vfs_sync =		ext2_sync,
	.vfs_vget =		ext2_vget,
	.vfs_fhtovp =		ext2_fhtovp,
	.vfs_vptofh =		ext2_vptofh,
	.vfs_checkexp =		ext2_check_export,
	.vfs_init =		ext2_init,
	.vfs_uninit =		ext2_uninit
};

VFS_SET(ext2fs_vfsops, ext2fs, VFCF_MPSAFE);
MODULE_VERSION(ext2fs, 1);

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 int ext2fs_inode_hash_lock;

/*
 * VFS Operations.
 *
 * mount system call
 */
static int
ext2_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
{
	struct ext2_args args;
	struct vnode *devvp;
	struct ext2mount *ump = NULL;
	struct m_ext2fs *fs;
	struct nlookupdata nd;
	mode_t accmode;
	int error, flags;
	size_t size;

	if ((error = copyin(data, (caddr_t)&args, sizeof (struct ext2_args))) != 0)
		return (error);

	/*
	 * 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;
		devvp = ump->um_devvp;
		error = 0;
		if (fs->e2fs_ronly == 0 && (mp->mnt_flag & MNT_RDONLY)) {
			error = VFS_SYNC(mp, MNT_WAIT);
			if (error)
				return (error);
			flags = WRITECLOSE;
			if (mp->mnt_flag & MNT_FORCE)
				flags |= FORCECLOSE;
			if (vfs_busy(mp, LK_NOWAIT))
				return (EBUSY);
			error = ext2_flushfiles(mp, flags);
			vfs_unbusy(mp);
			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;
			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
			VOP_OPEN(devvp, FREAD, FSCRED, NULL);
			VOP_CLOSE(devvp, FREAD | FWRITE, NULL);
			vn_unlock(devvp);
		}
		if (!error && (mp->mnt_flag & MNT_RELOAD))
			error = ext2_reload(mp);
		if (error)
			return (error);
		devvp = ump->um_devvp;
		if (fs->e2fs_ronly && (mp->mnt_kern_flag & MNTK_WANTRDWR)) {
			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.
			 */
			if (cred->cr_uid != 0) {
				vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
				error = VOP_EACCESS(devvp, VREAD | VWRITE, cred);
				if (error) {
					vn_unlock(devvp);
					return (error);
				}
				vn_unlock(devvp);
			}

			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;
			mp->mnt_flag &= ~MNT_RDONLY;

			vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
			VOP_OPEN(devvp, FREAD | FWRITE, FSCRED, NULL);
			VOP_CLOSE(devvp, FREAD, NULL);
			vn_unlock(devvp);
		}
		if (args.fspec == NULL) {
			/*
			 * Process export requests.
			 */
			return (vfs_export(mp, &ump->um_export, &args.export));
		}
	}

	/*
	 * Not an update, or updating the name: look up the name
	 * and verify that it refers to a sensible disk device.
	 */
	devvp = NULL;
	error = nlookup_init(&nd, args.fspec, UIO_USERSPACE, NLC_FOLLOW);
	if (error == 0)
		error = nlookup(&nd);
	if (error == 0)
		error = cache_vref(&nd.nl_nch, nd.nl_cred, &devvp);
	nlookup_done(&nd);
	if (error)
		return (error);

	if (!vn_isdisk(devvp, &error)) {
		vrele(devvp);
		return (error);
	}

	/*
	 * If mount by non-root, then verify that user has necessary
	 * permissions on the device.
	 *
	 * XXXRW: VOP_ACCESS() enough?
	 */
	if (cred->cr_uid != 0) {
		accmode = VREAD;
		if ((mp->mnt_flag & MNT_RDONLY) == 0)
			accmode |= VWRITE;
		vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
		if ((error = VOP_EACCESS(devvp, accmode, cred)) != 0) {
			vput(devvp);
			return (error);
		}
		vn_unlock(devvp);
	}

	if ((mp->mnt_flag & MNT_UPDATE) == 0) {
		error = ext2_mountfs(devvp, mp);
	} else {
		if (devvp != ump->um_devvp)
			error = EINVAL;	/* needs translation */
		else
			vrele(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().
	 */
	copyinstr(path, fs->e2fs_fsmnt, sizeof(fs->e2fs_fsmnt) - 1, &size);
	bzero(fs->e2fs_fsmnt + size, sizeof(fs->e2fs_fsmnt) - size);
	copyinstr(args.fspec, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, &size);
	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
	ext2_statfs(mp, &mp->mnt_stat, cred);
	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 > SBSIZE ? 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, fsbtodoff(fs, ext2_cg_location(fs, i)),
		    fs->e2fs_bsize, &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.
			 */
			brelse(bp);
			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);
}

struct scaninfo {
	int rescan;
	int allerror;
	int waitfor;
	struct vnode *devvp;
	struct m_ext2fs *fs;
};

static int
ext2_reload_scan(struct mount *mp, struct vnode *vp, void *data)
{
	struct scaninfo *info = data;
	struct inode *ip;
	struct buf *bp;
	int error;

	/*
	 * Try to recycle
	 */
	if (vrecycle(vp))
		return (0);

	/*
	 * Step 1: invalidate all cached file data.
	 */
	if (vinvalbuf(vp, 0, 0, 0))
		panic("ext2_reload: dirty2");
	/*
	 * Step 2: re-read inode data for all active vnodes.
	 */
	ip = VTOI(vp);
	error = bread(info->devvp,
	    fsbtodoff(info->fs, ino_to_fsba(info->fs, ip->i_number)),
	    (int)info->fs->e2fs_bsize, &bp);
	if (error) {
		brelse(bp);
		return (error);
	}

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

	brelse(bp);
	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 vnode *devvp;
	struct buf *bp;
	struct ext2fs *es;
	struct m_ext2fs *fs;
	struct csum *sump;
	struct scaninfo scaninfo;
	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");
	vn_unlock(devvp);

	/*
	 * Step 2: re-read superblock from disk.
	 * constants have been adjusted for ext2
	 */
	if ((error = bread(devvp, SBOFF, SBSIZE, &bp)) != 0) {
		brelse(bp);
		return (error);
	}
	es = (struct ext2fs *)bp->b_data;
	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);
	}
#ifdef UNKLAR
	if (fs->fs_sbsize < SBSIZE)
		bp->b_flags |= B_INVAL;
#endif
	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);
		}
	}

	scaninfo.rescan = 1;
	scaninfo.devvp = devvp;
	scaninfo.fs = fs;
	while (error == 0 && scaninfo.rescan) {
		scaninfo.rescan = 0;
		error = vmntvnodescan(mp, VMSC_GETVX, NULL, ext2_reload_scan,
		    &scaninfo);
	}
	return (error);
}

/*
 * 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 csum *sump;
	int error;
	int ronly;
	int i;
	u_long size;
	int32_t *lp;
	int32_t e2fs_maxcontig;

	/*
	 * Disallow multiple mounts of the same device.
	 * Disallow mounting of a device that is currently in use
	 * (except for root, which might share swap device for miniroot).
	 * Flush out any old buffers remaining from a previous use.
	 */
	if ((error = vfs_mountedon(devvp)) != 0)
		return (error);
	if (vcount(devvp) > 0)
		return (EBUSY);
	if ((error = vinvalbuf(devvp, V_SAVE, 0, 0)) != 0)
		return (error);
#ifdef READONLY
	/* Turn on this to force it to be read-only. */
	mp->mnt_flag |= MNT_RDONLY;
#endif
	ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
	error = VOP_OPEN(devvp, ronly ? FREAD : FREAD | FWRITE, FSCRED, NULL);
	vn_unlock(devvp);
	if (error)
		return (error);

	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;

	bp = NULL;
	ump = NULL;
	if ((error = bread(devvp, SBOFF, SBSIZE, &bp)) != 0)
		goto out;
	es = (struct ext2fs *)bp->b_data;
	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 Lock");
	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);
	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 = (qaddr_t)ump;
	mp->mnt_stat.f_fsid.val[0] = devid_from_dev(dev);
	mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
	mp->mnt_maxsymlinklen = EXT2_MAXSYMLINKLEN;
	mp->mnt_flag |= MNT_LOCAL;
	mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;
	ump->um_mountp = mp;
	ump->um_dev = dev;
	ump->um_devvp = devvp;

	/*
	 * 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);
	dev->si_mountpoint = mp;

	vfs_add_vnodeops(mp, &ext2_vnodeops, &mp->mnt_vn_norm_ops);
	vfs_add_vnodeops(mp, &ext2_specops, &mp->mnt_vn_spec_ops);
	vfs_add_vnodeops(mp, &ext2_fifoops, &mp->mnt_vn_fifo_ops);

	if (ronly == 0)
		ext2_sbupdate(ump, MNT_WAIT);
	return (0);
out:
	if (bp)
		brelse(bp);
	vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY);
	VOP_CLOSE(devvp, ronly ? FREAD : FREAD | FWRITE, NULL);
	vn_unlock(devvp);
	if (ump) {
		mtx_uninit(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)) != 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);
	}

	ump->um_devvp->v_rdev->si_mountpoint = NULL;

	vn_lock(ump->um_devvp, LK_EXCLUSIVE | LK_RETRY);
	error = VOP_CLOSE(ump->um_devvp, ronly ? FREAD : FREAD | FWRITE, NULL);
	vn_unlock(ump->um_devvp);

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

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

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

/*
 * Get filesystem statistics.
 */
static int
ext2_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
{
	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_type = mp->mnt_vfc->vfc_typenum;
	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;
	if (sbp != &mp->mnt_stat) {
		bcopy((caddr_t)mp->mnt_stat.f_mntfromname,
		    (caddr_t)&sbp->f_mntfromname[0], MNAMELEN);
	}
	return (0);
}

static int
ext2_statvfs(struct mount *mp, struct statvfs *sbp, struct ucred *cred)
{
	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_type = mp->mnt_vfc->vfc_typenum;
	sbp->f_bsize = EXT2_FRAG_SIZE(fs);
	sbp->f_frsize = 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);
}

static int
ext2_sync_scan(struct mount *mp, struct vnode *vp, void *data)
{
	struct scaninfo *info = data;
	struct inode *ip;
	int error;

	ip = VTOI(vp);
	if (vp->v_type == VNON ||
	    ((ip->i_flag &
	    (IN_ACCESS | IN_CHANGE | IN_MODIFIED | IN_UPDATE)) == 0 &&
	    (RB_EMPTY(&vp->v_rbdirty_tree) || (info->waitfor & MNT_LAZY))))
	{
		return (0);
	}
	if ((error = VOP_FSYNC(vp, info->waitfor, 0)) != 0)
		info->allerror = error;
	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 ext2mount *ump = VFSTOEXT2(mp);
	struct m_ext2fs *fs;
	struct scaninfo scaninfo;
	int error;

	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.
	 */
	scaninfo.allerror = 0;
	scaninfo.rescan = 1;
	scaninfo.waitfor = waitfor;
	while (scaninfo.rescan) {
		scaninfo.rescan = 0;
		vmntvnodescan(mp, VMSC_GETVP | VMSC_NOWAIT,
			      NULL, ext2_sync_scan, &scaninfo);
	}

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

int
ext2_alloc_vnode(struct mount *mp, ino_t ino, struct vnode **vpp)
{
	struct ext2mount *ump;
	struct vnode *vp;
	struct inode *ip;
	int error;

	ump = VFSTOEXT2(mp);
	/*
	 * Lock out the creation of new entries in the FFS hash table in
	 * case getnewvnode() or MALLOC() blocks, otherwise a duplicate
	 * may occur!
	 */
	if (ext2fs_inode_hash_lock) {
		while (ext2fs_inode_hash_lock) {
			ext2fs_inode_hash_lock = -1;
			tsleep(&ext2fs_inode_hash_lock, 0, "e2vget", 0);
		}
		return (-1);
	}
	ext2fs_inode_hash_lock = 1;

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

	/* Allocate a new vnode/inode. */
	if ((error = getnewvnode(VT_EXT2FS, mp, &vp, VLKTIMEOUT,
	    LK_CANRECURSE)) != 0) {
		if (ext2fs_inode_hash_lock < 0)
			wakeup(&ext2fs_inode_hash_lock);
		ext2fs_inode_hash_lock = 0;
		*vpp = NULL;
		free(ip, M_EXT2NODE);
		return (error);
	}
	//lockmgr(vp->v_vnlock, LK_EXCLUSIVE, NULL);
	vp->v_data = ip;
	ip->i_vnode = vp;
	ip->i_e2fs = ump->um_e2fs;
	ip->i_dev = ump->um_dev;
	ip->i_ump = ump;
	ip->i_number = ino;
	ip->i_block_group = ino_to_cg(ip->i_e2fs, ino);
	ip->i_next_alloc_block = 0;
	ip->i_next_alloc_goal = 0;

	/*
	 * Put it onto its hash chain.  Since our vnode is locked, 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.
	 */
	if (ext2_ihashins(ip)) {
		printf("ext2_alloc_vnode: ihashins collision, retrying inode %ld\n",
		    (long)ip->i_number);
		*vpp = NULL;
		vp->v_type = VBAD;
		vx_put(vp);
		free(ip, M_EXT2NODE);
		return (-1);
	}

	if (ext2fs_inode_hash_lock < 0)
		wakeup(&ext2fs_inode_hash_lock);
	ext2fs_inode_hash_lock = 0;
	*vpp = vp;

	return (0);
}

/*
 * 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, struct vnode *dvp, ino_t ino, struct vnode **vpp)
{
	struct m_ext2fs *fs;
	struct inode *ip;
	struct ext2mount *ump;
	struct buf *bp;
	struct vnode *vp;
	unsigned int i, used_blocks;
	int error;

	ump = VFSTOEXT2(mp);
restart:
	if ((*vpp = ext2_ihashget(ump->um_dev, ino)) != NULL)
		return (0);
	if (ext2_alloc_vnode(mp, ino, &vp) == -1)
		goto restart;
	ip = VTOI(vp);
	fs = ip->i_e2fs;

	/* Read in the disk contents for the inode, copy into the inode. */
	if ((error = bread(ump->um_devvp, fsbtodoff(fs, ino_to_fsba(fs, ino)),
	    (int)fs->e2fs_bsize, &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().
		 */
		vp->v_type = VBAD;
		brelse(bp);
		vx_put(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);
		vx_put(vp);
		*vpp = NULL;
		return (error);
	}

	/*
	 * 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;
	}
#ifdef EXT2FS_PRINT_EXTENTS
	ext2_print_inode(ip);
	ext4_ext_print_extent_tree_status(ip);
#endif
	bqrelse(bp);

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

	/*
	 * Finish inode initialization now that aliasing has been resolved.
	 */
	vref(ip->i_devvp);
	/*
	 * Set up a generation number for this inode if it does not
	 * already have one. This should only happen on old filesystems.
	 */
	if (ip->i_gen == 0) {
		ip->i_gen = krandom() / 2 + 1;
		if ((vp->v_mount->mnt_flag & MNT_RDONLY) == 0)
			ip->i_flag |= IN_MODIFIED;
	}
	/*
	 * Return the locked and refd vnode.
	 */
	vx_downgrade(vp);	/* downgrade VX lock to VN lock */
	*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 vnode *rootvp, struct fid *fhp,
    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, NULL, ufhp->ufid_ino, &nvp);
	if (error) {
		*vpp = NULLVP;
		return (error);
	}
	ip = VTOI(nvp);
	if (ip->i_mode == 0 ||
	    ip->i_gen != ufhp->ufid_gen || ip->i_nlink <= 0) {
		vput(nvp);
		*vpp = NULLVP;
		return (ESTALE);
	}
	*vpp = nvp;
	return (0);
}

/*
 * Vnode pointer to File handle
 */
/* ARGSUSED */
static int
ext2_vptofh(struct vnode *vp, struct fid *fhp)
{
	struct inode *ip;
	struct ufid *ufhp;

	ip = VTOI(vp);
	ufhp = (struct ufid *)fhp;
	ufhp->ufid_len = sizeof(struct ufid);
	ufhp->ufid_ino = ip->i_number;
	ufhp->ufid_gen = ip->i_gen;
	return (0);
}

/*
 * This is the generic part of fhtovp called after the underlying
 * filesystem has validated the file handle.
 *
 * Verify that a host should have access to a filesystem.
 */
static int
ext2_check_export(struct mount *mp, struct sockaddr *nam, int *exflagsp,
                 struct ucred **credanonp)
{
	struct netcred *np;
	struct ext2mount *ump;

	ump = VFSTOEXT2(mp);
	/*
	 * Get the export permission structure for this <mp, client> tuple.
	 */
	np = vfs_export_lookup(mp, &ump->um_export, nam);
	if (np == NULL)
		return (EACCES);

	*exflagsp = np->netc_exflags;
	*credanonp = &np->netc_anon;
	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);

	bp = getblk(mp->um_devvp, SBOFF, SBSIZE, 0, 0);
	bcopy((caddr_t)es, bp->b_data, (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);
}

static 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, fsbtodoff(fs,
		    ext2_cg_location(fs, i)),
		    fs->e2fs_bsize, 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, struct vnode **vpp)
{
	struct vnode *nvp;
	int error;

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

/*
 * Initialize ext2 filesystems, done only once.
 */
static int
ext2_init(struct vfsconf *vfsp)
{
	static int done;

	if (done)
		return (0);
	done = 1;
	ext2_ihashinit();

	return (0);
}

static int
ext2_uninit(struct vfsconf *vfsp)
{

	ext2_ihashuninit();

	return (0);
}