/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
 * Copyright 2019 Joyent, Inc.
 */

#include <sys/zfs_context.h>
#include <sys/spa.h>
#include <sys/spa_impl.h>
#include <sys/vdev_file.h>
#include <sys/vdev_impl.h>
#include <sys/vdev_trim.h>
#include <sys/zio.h>
#include <sys/fs/zfs.h>
#include <sys/fm/fs/zfs.h>
#include <sys/abd.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>

/*
 * Virtual device vector for files.
 */

static void
vdev_file_hold(vdev_t *vd)
{
        ASSERT(vd->vdev_path != NULL);
}

static void
vdev_file_rele(vdev_t *vd)
{
        ASSERT(vd->vdev_path != NULL);
}

static int
vdev_file_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
    uint64_t *ashift)
{
        vdev_file_t *vf;
        vnode_t *vp;
        vattr_t vattr;
        int error;

        /*
         * Rotational optimizations only make sense on block devices.
         */
        vd->vdev_nonrot = B_TRUE;

        /*
         * Allow TRIM on file based vdevs.  This may not always be supported,
         * since it depends on your kernel version and underlying filesystem
         * type but it is always safe to attempt.
         */
        vd->vdev_has_trim = B_TRUE;

        /*
         * Disable secure TRIM on file based vdevs.  There is no way to
         * request this behavior from the underlying filesystem.
         */
        vd->vdev_has_securetrim = B_FALSE;

        /*
         * We must have a pathname, and it must be absolute.
         */
        if (vd->vdev_path == NULL || vd->vdev_path[0] != '/') {
                vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
                return (SET_ERROR(EINVAL));
        }

        /*
         * Reopen the device if it's not currently open.  Otherwise,
         * just update the physical size of the device.
         */
        if (vd->vdev_tsd != NULL) {
                ASSERT(vd->vdev_reopening);
                vf = vd->vdev_tsd;
                goto skip_open;
        }

        vf = vd->vdev_tsd = kmem_zalloc(sizeof (vdev_file_t), KM_SLEEP);

        /*
         * We always open the files from the root of the global zone, even if
         * we're in a local zone.  If the user has gotten to this point, the
         * administrator has already decided that the pool should be available
         * to local zone users, so the underlying devices should be as well.
         */
        ASSERT(vd->vdev_path != NULL && vd->vdev_path[0] == '/');
        error = vn_openat(vd->vdev_path + 1, UIO_SYSSPACE,
            spa_mode(vd->vdev_spa) | FOFFMAX, 0, &vp, 0, 0, rootdir, -1);

        if (error) {
                vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
                return (error);
        }

        vf->vf_vnode = vp;

#ifdef _KERNEL
        /*
         * Make sure it's a regular file.
         */
        if (vp->v_type != VREG) {
                vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
                return (SET_ERROR(ENODEV));
        }
#endif

skip_open:
        /*
         * Determine the physical size of the file.
         */
        vattr.va_mask = AT_SIZE;
        error = VOP_GETATTR(vf->vf_vnode, &vattr, 0, kcred, NULL);
        if (error) {
                vd->vdev_stat.vs_aux = VDEV_AUX_OPEN_FAILED;
                return (error);
        }

        *max_psize = *psize = vattr.va_size;
        *ashift = SPA_MINBLOCKSHIFT;

        return (0);
}

static void
vdev_file_close(vdev_t *vd)
{
        vdev_file_t *vf = vd->vdev_tsd;

        if (vd->vdev_reopening || vf == NULL)
                return;

        if (vf->vf_vnode != NULL) {
                (void) VOP_PUTPAGE(vf->vf_vnode, 0, 0, B_INVAL, kcred, NULL);
                (void) VOP_CLOSE(vf->vf_vnode, spa_mode(vd->vdev_spa), 1, 0,
                    kcred, NULL);
                VN_RELE(vf->vf_vnode);
        }

        vd->vdev_delayed_close = B_FALSE;
        kmem_free(vf, sizeof (vdev_file_t));
        vd->vdev_tsd = NULL;
}

/*
 * Implements the interrupt side for file vdev types. This routine will be
 * called when the I/O completes allowing us to transfer the I/O to the
 * interrupt taskqs. For consistency, the code structure mimics disk vdev
 * types.
 */
static int
vdev_file_io_intr(buf_t *bp)
{
        vdev_buf_t *vb = (vdev_buf_t *)bp;
        zio_t *zio = vb->vb_io;

        zio->io_error = (geterror(bp) != 0 ? EIO : 0);
        if (zio->io_error == 0 && bp->b_resid != 0)
                zio->io_error = SET_ERROR(ENOSPC);

        if (zio->io_type == ZIO_TYPE_READ) {
                abd_return_buf_copy(zio->io_abd, bp->b_un.b_addr, zio->io_size);
        } else {
                abd_return_buf(zio->io_abd, bp->b_un.b_addr, zio->io_size);
        }

        kmem_free(vb, sizeof (vdev_buf_t));
        zio_delay_interrupt(zio);
        return (0);
}

static void
vdev_file_io_strategy(void *arg)
{
        buf_t *bp = arg;
        vnode_t *vp = bp->b_private;
        ssize_t resid;
        int error;

        error = vn_rdwr((bp->b_flags & B_READ) ? UIO_READ : UIO_WRITE,
            vp, bp->b_un.b_addr, bp->b_bcount, ldbtob(bp->b_lblkno),
            UIO_SYSSPACE, 0, RLIM64_INFINITY, kcred, &resid);

        if (error == 0) {
                bp->b_resid = resid;
                biodone(bp);
        } else {
                bioerror(bp, error);
                biodone(bp);
        }
}

static void
vdev_file_io_start(zio_t *zio)
{
        vdev_t *vd = zio->io_vd;
        vdev_file_t *vf = vd->vdev_tsd;
        vdev_buf_t *vb;
        buf_t *bp;

        if (zio->io_type == ZIO_TYPE_IOCTL) {
                /* XXPOLICY */
                if (!vdev_readable(vd)) {
                        zio->io_error = SET_ERROR(ENXIO);
                        zio_interrupt(zio);
                        return;
                }

                switch (zio->io_cmd) {
                case DKIOCFLUSHWRITECACHE:
                        zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
                            kcred, NULL);
                        break;
                default:
                        zio->io_error = SET_ERROR(ENOTSUP);
                }

                zio_execute(zio);
                return;
        } else if (zio->io_type == ZIO_TYPE_TRIM) {
                struct flock64 flck;

                ASSERT3U(zio->io_size, !=, 0);
                bzero(&flck, sizeof (flck));
                flck.l_type = F_FREESP;
                flck.l_start = zio->io_offset;
                flck.l_len = zio->io_size;
                flck.l_whence = 0;

                zio->io_error = VOP_SPACE(vf->vf_vnode, F_FREESP, &flck,
                    0, 0, kcred, NULL);

                zio_execute(zio);
                return;
        }

        ASSERT(zio->io_type == ZIO_TYPE_READ || zio->io_type == ZIO_TYPE_WRITE);
        zio->io_target_timestamp = zio_handle_io_delay(zio);

        vb = kmem_alloc(sizeof (vdev_buf_t), KM_SLEEP);

        vb->vb_io = zio;
        bp = &vb->vb_buf;

        bioinit(bp);
        bp->b_flags = (zio->io_type == ZIO_TYPE_READ ? B_READ : B_WRITE);
        bp->b_bcount = zio->io_size;

        if (zio->io_type == ZIO_TYPE_READ) {
                bp->b_un.b_addr =
                    abd_borrow_buf(zio->io_abd, zio->io_size);
        } else {
                bp->b_un.b_addr =
                    abd_borrow_buf_copy(zio->io_abd, zio->io_size);
        }

        bp->b_lblkno = lbtodb(zio->io_offset);
        bp->b_bufsize = zio->io_size;
        bp->b_private = vf->vf_vnode;
        bp->b_iodone = vdev_file_io_intr;

        VERIFY3U(taskq_dispatch(system_taskq, vdev_file_io_strategy, bp,
            TQ_SLEEP), !=, TASKQID_INVALID);
}

/* ARGSUSED */
static void
vdev_file_io_done(zio_t *zio)
{
}

vdev_ops_t vdev_file_ops = {
        .vdev_op_open = vdev_file_open,
        .vdev_op_close = vdev_file_close,
        .vdev_op_asize = vdev_default_asize,
        .vdev_op_io_start = vdev_file_io_start,
        .vdev_op_io_done = vdev_file_io_done,
        .vdev_op_state_change = NULL,
        .vdev_op_need_resilver = NULL,
        .vdev_op_hold = vdev_file_hold,
        .vdev_op_rele = vdev_file_rele,
        .vdev_op_remap = NULL,
        .vdev_op_xlate = vdev_default_xlate,
        .vdev_op_dumpio = NULL,
        .vdev_op_type = VDEV_TYPE_FILE,         /* name of this vdev type */
        .vdev_op_leaf = B_TRUE                  /* leaf vdev */
};

/*
 * From userland we access disks just like files.
 */
#ifndef _KERNEL

vdev_ops_t vdev_disk_ops = {
        .vdev_op_open = vdev_file_open,
        .vdev_op_close = vdev_file_close,
        .vdev_op_asize = vdev_default_asize,
        .vdev_op_io_start = vdev_file_io_start,
        .vdev_op_io_done = vdev_file_io_done,
        .vdev_op_state_change = NULL,
        .vdev_op_need_resilver = NULL,
        .vdev_op_hold = vdev_file_hold,
        .vdev_op_rele = vdev_file_rele,
        .vdev_op_remap = NULL,
        .vdev_op_xlate = vdev_default_xlate,
        .vdev_op_dumpio = NULL,
        .vdev_op_type = VDEV_TYPE_DISK,         /* name of this vdev type */
        .vdev_op_leaf = B_TRUE                  /* leaf vdev */
};

#endif