// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2014-2016 Christoph Hellwig.
 */
#include <linux/exportfs.h>
#include <linux/iomap.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/pr.h>

#include <linux/nfsd/debug.h>
#include <scsi/scsi_proto.h>
#include <scsi/scsi_common.h>
#include <scsi/scsi_request.h>

#include "blocklayoutxdr.h"
#include "pnfs.h"

#define NFSDDBG_FACILITY        NFSDDBG_PNFS


static __be32
nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
                struct nfsd4_layoutget *args)
{
        struct nfsd4_layout_seg *seg = &args->lg_seg;
        struct super_block *sb = inode->i_sb;
        u32 block_size = i_blocksize(inode);
        struct pnfs_block_extent *bex;
        struct iomap iomap;
        u32 device_generation = 0;
        int error;

        if (seg->offset & (block_size - 1)) {
                dprintk("pnfsd: I/O misaligned\n");
                goto out_layoutunavailable;
        }

        /*
         * Some clients barf on non-zero block numbers for NONE or INVALID
         * layouts, so make sure to zero the whole structure.
         */
        error = -ENOMEM;
        bex = kzalloc(sizeof(*bex), GFP_KERNEL);
        if (!bex)
                goto out_error;
        args->lg_content = bex;

        error = sb->s_export_op->map_blocks(inode, seg->offset, seg->length,
                                            &iomap, seg->iomode != IOMODE_READ,
                                            &device_generation);
        if (error) {
                if (error == -ENXIO)
                        goto out_layoutunavailable;
                goto out_error;
        }

        if (iomap.length < args->lg_minlength) {
                dprintk("pnfsd: extent smaller than minlength\n");
                goto out_layoutunavailable;
        }

        switch (iomap.type) {
        case IOMAP_MAPPED:
                if (seg->iomode == IOMODE_READ)
                        bex->es = PNFS_BLOCK_READ_DATA;
                else
                        bex->es = PNFS_BLOCK_READWRITE_DATA;
                bex->soff = iomap.addr;
                break;
        case IOMAP_UNWRITTEN:
                if (seg->iomode & IOMODE_RW) {
                        /*
                         * Crack monkey special case from section 2.3.1.
                         */
                        if (args->lg_minlength == 0) {
                                dprintk("pnfsd: no soup for you!\n");
                                goto out_layoutunavailable;
                        }

                        bex->es = PNFS_BLOCK_INVALID_DATA;
                        bex->soff = iomap.addr;
                        break;
                }
                /*FALLTHRU*/
        case IOMAP_HOLE:
                if (seg->iomode == IOMODE_READ) {
                        bex->es = PNFS_BLOCK_NONE_DATA;
                        break;
                }
                /*FALLTHRU*/
        case IOMAP_DELALLOC:
        default:
                WARN(1, "pnfsd: filesystem returned %d extent\n", iomap.type);
                goto out_layoutunavailable;
        }

        error = nfsd4_set_deviceid(&bex->vol_id, fhp, device_generation);
        if (error)
                goto out_error;
        bex->foff = iomap.offset;
        bex->len = iomap.length;

        seg->offset = iomap.offset;
        seg->length = iomap.length;

        dprintk("GET: 0x%llx:0x%llx %d\n", bex->foff, bex->len, bex->es);
        return 0;

out_error:
        seg->length = 0;
        return nfserrno(error);
out_layoutunavailable:
        seg->length = 0;
        return nfserr_layoutunavailable;
}

static __be32
nfsd4_block_commit_blocks(struct inode *inode, struct nfsd4_layoutcommit *lcp,
                struct iomap *iomaps, int nr_iomaps)
{
        loff_t new_size = lcp->lc_last_wr + 1;
        struct iattr iattr = { .ia_valid = 0 };
        int error;

        if (lcp->lc_mtime.tv_nsec == UTIME_NOW ||
            timespec64_compare(&lcp->lc_mtime, &inode->i_mtime) < 0)
                lcp->lc_mtime = current_time(inode);
        iattr.ia_valid |= ATTR_ATIME | ATTR_CTIME | ATTR_MTIME;
        iattr.ia_atime = iattr.ia_ctime = iattr.ia_mtime = lcp->lc_mtime;

        if (new_size > i_size_read(inode)) {
                iattr.ia_valid |= ATTR_SIZE;
                iattr.ia_size = new_size;
        }

        error = inode->i_sb->s_export_op->commit_blocks(inode, iomaps,
                        nr_iomaps, &iattr);
        kfree(iomaps);
        return nfserrno(error);
}

#ifdef CONFIG_NFSD_BLOCKLAYOUT
static int
nfsd4_block_get_device_info_simple(struct super_block *sb,
                struct nfsd4_getdeviceinfo *gdp)
{
        struct pnfs_block_deviceaddr *dev;
        struct pnfs_block_volume *b;

        dev = kzalloc(sizeof(struct pnfs_block_deviceaddr) +
                      sizeof(struct pnfs_block_volume), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        gdp->gd_device = dev;

        dev->nr_volumes = 1;
        b = &dev->volumes[0];

        b->type = PNFS_BLOCK_VOLUME_SIMPLE;
        b->simple.sig_len = PNFS_BLOCK_UUID_LEN;
        return sb->s_export_op->get_uuid(sb, b->simple.sig, &b->simple.sig_len,
                        &b->simple.offset);
}

static __be32
nfsd4_block_proc_getdeviceinfo(struct super_block *sb,
                struct svc_rqst *rqstp,
                struct nfs4_client *clp,
                struct nfsd4_getdeviceinfo *gdp)
{
        if (sb->s_bdev != sb->s_bdev->bd_contains)
                return nfserr_inval;
        return nfserrno(nfsd4_block_get_device_info_simple(sb, gdp));
}

static __be32
nfsd4_block_proc_layoutcommit(struct inode *inode,
                struct nfsd4_layoutcommit *lcp)
{
        struct iomap *iomaps;
        int nr_iomaps;

        nr_iomaps = nfsd4_block_decode_layoutupdate(lcp->lc_up_layout,
                        lcp->lc_up_len, &iomaps, i_blocksize(inode));
        if (nr_iomaps < 0)
                return nfserrno(nr_iomaps);

        return nfsd4_block_commit_blocks(inode, lcp, iomaps, nr_iomaps);
}

const struct nfsd4_layout_ops bl_layout_ops = {
        /*
         * Pretend that we send notification to the client.  This is a blatant
         * lie to force recent Linux clients to cache our device IDs.
         * We rarely ever change the device ID, so the harm of leaking deviceids
         * for a while isn't too bad.  Unfortunately RFC5661 is a complete mess
         * in this regard, but I filed errata 4119 for this a while ago, and
         * hopefully the Linux client will eventually start caching deviceids
         * without this again.
         */
        .notify_types           =
                        NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
        .proc_getdeviceinfo     = nfsd4_block_proc_getdeviceinfo,
        .encode_getdeviceinfo   = nfsd4_block_encode_getdeviceinfo,
        .proc_layoutget         = nfsd4_block_proc_layoutget,
        .encode_layoutget       = nfsd4_block_encode_layoutget,
        .proc_layoutcommit      = nfsd4_block_proc_layoutcommit,
};
#endif /* CONFIG_NFSD_BLOCKLAYOUT */

#ifdef CONFIG_NFSD_SCSILAYOUT
static int nfsd4_scsi_identify_device(struct block_device *bdev,
                struct pnfs_block_volume *b)
{
        struct request_queue *q = bdev->bd_disk->queue;
        struct request *rq;
        struct scsi_request *req;
        /*
         * The allocation length (passed in bytes 3 and 4 of the INQUIRY
         * command descriptor block) specifies the number of bytes that have
         * been allocated for the data-in buffer.
         * 252 is the highest one-byte value that is a multiple of 4.
         * 65532 is the highest two-byte value that is a multiple of 4.
         */
        size_t bufflen = 252, maxlen = 65532, len, id_len;
        u8 *buf, *d, type, assoc;
        int retries = 1, error;

        if (WARN_ON_ONCE(!blk_queue_scsi_passthrough(q)))
                return -EINVAL;

again:
        buf = kzalloc(bufflen, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
        if (IS_ERR(rq)) {
                error = -ENOMEM;
                goto out_free_buf;
        }
        req = scsi_req(rq);

        error = blk_rq_map_kern(q, rq, buf, bufflen, GFP_KERNEL);
        if (error)
                goto out_put_request;

        req->cmd[0] = INQUIRY;
        req->cmd[1] = 1;
        req->cmd[2] = 0x83;
        req->cmd[3] = bufflen >> 8;
        req->cmd[4] = bufflen & 0xff;
        req->cmd_len = COMMAND_SIZE(INQUIRY);

        blk_execute_rq(rq->q, NULL, rq, 1);
        if (req->result) {
                pr_err("pNFS: INQUIRY 0x83 failed with: %x\n",
                        req->result);
                error = -EIO;
                goto out_put_request;
        }

        len = (buf[2] << 8) + buf[3] + 4;
        if (len > bufflen) {
                if (len <= maxlen && retries--) {
                        blk_put_request(rq);
                        kfree(buf);
                        bufflen = len;
                        goto again;
                }
                pr_err("pNFS: INQUIRY 0x83 response invalid (len = %zd)\n",
                        len);
                goto out_put_request;
        }

        d = buf + 4;
        for (d = buf + 4; d < buf + len; d += id_len + 4) {
                id_len = d[3];
                type = d[1] & 0xf;
                assoc = (d[1] >> 4) & 0x3;

                /*
                 * We only care about a EUI-64 and NAA designator types
                 * with LU association.
                 */
                if (assoc != 0x00)
                        continue;
                if (type != 0x02 && type != 0x03)
                        continue;
                if (id_len != 8 && id_len != 12 && id_len != 16)
                        continue;

                b->scsi.code_set = PS_CODE_SET_BINARY;
                b->scsi.designator_type = type == 0x02 ?
                        PS_DESIGNATOR_EUI64 : PS_DESIGNATOR_NAA;
                b->scsi.designator_len = id_len;
                memcpy(b->scsi.designator, d + 4, id_len);

                /*
                 * If we found a 8 or 12 byte descriptor continue on to
                 * see if a 16 byte one is available.  If we find a
                 * 16 byte descriptor we're done.
                 */
                if (id_len == 16)
                        break;
        }

out_put_request:
        blk_put_request(rq);
out_free_buf:
        kfree(buf);
        return error;
}

#define NFSD_MDS_PR_KEY         0x0100000000000000ULL

/*
 * We use the client ID as a unique key for the reservations.
 * This allows us to easily fence a client when recalls fail.
 */
static u64 nfsd4_scsi_pr_key(struct nfs4_client *clp)
{
        return ((u64)clp->cl_clientid.cl_boot << 32) | clp->cl_clientid.cl_id;
}

static int
nfsd4_block_get_device_info_scsi(struct super_block *sb,
                struct nfs4_client *clp,
                struct nfsd4_getdeviceinfo *gdp)
{
        struct pnfs_block_deviceaddr *dev;
        struct pnfs_block_volume *b;
        const struct pr_ops *ops;
        int error;

        dev = kzalloc(sizeof(struct pnfs_block_deviceaddr) +
                      sizeof(struct pnfs_block_volume), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        gdp->gd_device = dev;

        dev->nr_volumes = 1;
        b = &dev->volumes[0];

        b->type = PNFS_BLOCK_VOLUME_SCSI;
        b->scsi.pr_key = nfsd4_scsi_pr_key(clp);

        error = nfsd4_scsi_identify_device(sb->s_bdev, b);
        if (error)
                return error;

        ops = sb->s_bdev->bd_disk->fops->pr_ops;
        if (!ops) {
                pr_err("pNFS: device %s does not support PRs.\n",
                        sb->s_id);
                return -EINVAL;
        }

        error = ops->pr_register(sb->s_bdev, 0, NFSD_MDS_PR_KEY, true);
        if (error) {
                pr_err("pNFS: failed to register key for device %s.\n",
                        sb->s_id);
                return -EINVAL;
        }

        error = ops->pr_reserve(sb->s_bdev, NFSD_MDS_PR_KEY,
                        PR_EXCLUSIVE_ACCESS_REG_ONLY, 0);
        if (error) {
                pr_err("pNFS: failed to reserve device %s.\n",
                        sb->s_id);
                return -EINVAL;
        }

        return 0;
}

static __be32
nfsd4_scsi_proc_getdeviceinfo(struct super_block *sb,
                struct svc_rqst *rqstp,
                struct nfs4_client *clp,
                struct nfsd4_getdeviceinfo *gdp)
{
        if (sb->s_bdev != sb->s_bdev->bd_contains)
                return nfserr_inval;
        return nfserrno(nfsd4_block_get_device_info_scsi(sb, clp, gdp));
}
static __be32
nfsd4_scsi_proc_layoutcommit(struct inode *inode,
                struct nfsd4_layoutcommit *lcp)
{
        struct iomap *iomaps;
        int nr_iomaps;

        nr_iomaps = nfsd4_scsi_decode_layoutupdate(lcp->lc_up_layout,
                        lcp->lc_up_len, &iomaps, i_blocksize(inode));
        if (nr_iomaps < 0)
                return nfserrno(nr_iomaps);

        return nfsd4_block_commit_blocks(inode, lcp, iomaps, nr_iomaps);
}

static void
nfsd4_scsi_fence_client(struct nfs4_layout_stateid *ls)
{
        struct nfs4_client *clp = ls->ls_stid.sc_client;
        struct block_device *bdev = ls->ls_file->f_path.mnt->mnt_sb->s_bdev;

        bdev->bd_disk->fops->pr_ops->pr_preempt(bdev, NFSD_MDS_PR_KEY,
                        nfsd4_scsi_pr_key(clp), 0, true);
}

const struct nfsd4_layout_ops scsi_layout_ops = {
        /*
         * Pretend that we send notification to the client.  This is a blatant
         * lie to force recent Linux clients to cache our device IDs.
         * We rarely ever change the device ID, so the harm of leaking deviceids
         * for a while isn't too bad.  Unfortunately RFC5661 is a complete mess
         * in this regard, but I filed errata 4119 for this a while ago, and
         * hopefully the Linux client will eventually start caching deviceids
         * without this again.
         */
        .notify_types           =
                        NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
        .proc_getdeviceinfo     = nfsd4_scsi_proc_getdeviceinfo,
        .encode_getdeviceinfo   = nfsd4_block_encode_getdeviceinfo,
        .proc_layoutget         = nfsd4_block_proc_layoutget,
        .encode_layoutget       = nfsd4_block_encode_layoutget,
        .proc_layoutcommit      = nfsd4_scsi_proc_layoutcommit,
        .fence_client           = nfsd4_scsi_fence_client,
};
#endif /* CONFIG_NFSD_SCSILAYOUT */