/*
   * Copyright (c) 2016 Tom Haynes <loghyr@primarydata.com>
   *
   * The following implements a super-simple flex-file server
   * where the NFSv4.1 mds is also the ds. And the storage is
   * the same. I.e., writing to the mds via a NFSv4.1 WRITE
   * goes to the same location as the NFSv3 WRITE.
   */
  #include <linux/slab.h>
  
  #include <linux/nfsd/debug.h>
  
  #include <linux/sunrpc/addr.h>
  
  #include "flexfilelayoutxdr.h"
  #include "pnfs.h"
  
  #define NFSDDBG_FACILITY	NFSDDBG_PNFS
  
  static __be32
  nfsd4_ff_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
  		struct nfsd4_layoutget *args)
  {
  	struct nfsd4_layout_seg *seg = &args->lg_seg;
  	u32 device_generation = 0;
  	int error;
  	uid_t u;
  
  	struct pnfs_ff_layout *fl;
  
  	/*
  	 * The super simple flex file server has 1 mirror, 1 data server,
  	 * and 1 file handle. So instead of 4 allocs, do 1 for now.
  	 * Zero it out for the stateid - don't want junk in there!
  	 */
  	error = -ENOMEM;
  	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
  	if (!fl)
  		goto out_error;
  	args->lg_content = fl;
  
  	/*
  	 * Avoid layout commit, try to force the I/O to the DS,
  	 * and for fun, cause all IOMODE_RW layout segments to
  	 * effectively be WRITE only.
  	 */
  	fl->flags = FF_FLAGS_NO_LAYOUTCOMMIT | FF_FLAGS_NO_IO_THRU_MDS |
  		    FF_FLAGS_NO_READ_IO;
  
  	/* Do not allow a IOMODE_READ segment to have write pemissions */
  	if (seg->iomode == IOMODE_READ) {
  		u = from_kuid(&init_user_ns, inode->i_uid) + 1;
  		fl->uid = make_kuid(&init_user_ns, u);
  	} else
  		fl->uid = inode->i_uid;
  	fl->gid = inode->i_gid;
  
  	error = nfsd4_set_deviceid(&fl->deviceid, fhp, device_generation);
  	if (error)
  		goto out_error;
  
  	fl->fh.size = fhp->fh_handle.fh_size;
  	memcpy(fl->fh.data, &fhp->fh_handle.fh_base, fl->fh.size);
  
  	/* Give whole file layout segments */
  	seg->offset = 0;
  	seg->length = NFS4_MAX_UINT64;
  
  	dprintk("GET: 0x%llx:0x%llx %d
  ", seg->offset, seg->length,
  		seg->iomode);
  	return 0;
  
  out_error:
  	seg->length = 0;
  	return nfserrno(error);
  }
  
  static __be32
  nfsd4_ff_proc_getdeviceinfo(struct super_block *sb, struct svc_rqst *rqstp,
  		struct nfs4_client *clp, struct nfsd4_getdeviceinfo *gdp)
  {
  	struct pnfs_ff_device_addr *da;
  
  	u16 port;
  	char addr[INET6_ADDRSTRLEN];
  
  	da = kzalloc(sizeof(struct pnfs_ff_device_addr), GFP_KERNEL);
  	if (!da)
  		return nfserrno(-ENOMEM);
  
  	gdp->gd_device = da;
  
  	da->version = 3;
  	da->minor_version = 0;
  
  	da->rsize = svc_max_payload(rqstp);
  	da->wsize = da->rsize;
  
  	rpc_ntop((struct sockaddr *)&rqstp->rq_daddr,
  		 addr, INET6_ADDRSTRLEN);
  	if (rqstp->rq_daddr.ss_family == AF_INET) {
  		struct sockaddr_in *sin;
  
  		sin = (struct sockaddr_in *)&rqstp->rq_daddr;
  		port = ntohs(sin->sin_port);
  		snprintf(da->netaddr.netid, FF_NETID_LEN + 1, "tcp");
  		da->netaddr.netid_len = 3;
  	} else {
  		struct sockaddr_in6 *sin6;
  
  		sin6 = (struct sockaddr_in6 *)&rqstp->rq_daddr;
  		port = ntohs(sin6->sin6_port);
  		snprintf(da->netaddr.netid, FF_NETID_LEN + 1, "tcp6");
  		da->netaddr.netid_len = 4;
  	}
  
  	da->netaddr.addr_len =
  		snprintf(da->netaddr.addr, FF_ADDR_LEN + 1,
  			 "%s.%hhu.%hhu", addr, port >> 8, port & 0xff);
  
  	da->tightly_coupled = false;
  
  	return 0;
  }
  
  const struct nfsd4_layout_ops ff_layout_ops = {
  	.notify_types		=
  			NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,

  	.disable_recalls	= true,

  	.proc_getdeviceinfo	= nfsd4_ff_proc_getdeviceinfo,
  	.encode_getdeviceinfo	= nfsd4_ff_encode_getdeviceinfo,
  	.proc_layoutget		= nfsd4_ff_proc_layoutget,
  	.encode_layoutget	= nfsd4_ff_encode_layoutget,
  };