/*******************************************************************************
   * Filename:  target_core_file.c
   *
   * This file contains the Storage Engine <-> FILEIO transport specific functions
   *

   * (c) Copyright 2005-2013 Datera, Inc.

   *
   * Nicholas A. Bellinger <nab@kernel.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   ******************************************************************************/

  #include <linux/string.h>
  #include <linux/parser.h>
  #include <linux/timer.h>
  #include <linux/blkdev.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>

  #include <linux/module.h>

  #include <linux/vmalloc.h>

  #include <linux/falloc.h>

  #include <scsi/scsi_proto.h>

  #include <asm/unaligned.h>

  
  #include <target/target_core_base.h>

  #include <target/target_core_backend.h>

  
  #include "target_core_file.h"

  static inline struct fd_dev *FD_DEV(struct se_device *dev)
  {
  	return container_of(dev, struct fd_dev, dev);
  }

  static int fd_attach_hba(struct se_hba *hba, u32 host_id)
  {
  	struct fd_host *fd_host;
  
  	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);

  	if (!fd_host) {
  		pr_err("Unable to allocate memory for struct fd_host
  ");

  		return -ENOMEM;

  	}
  
  	fd_host->fd_host_id = host_id;

  	hba->hba_ptr = fd_host;

  	pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"

  		" Target Core Stack %s
  ", hba->hba_id, FD_VERSION,

  		TARGET_CORE_VERSION);

  	pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic
  ",
  		hba->hba_id, fd_host->fd_host_id);

  
  	return 0;
  }
  
  static void fd_detach_hba(struct se_hba *hba)
  {
  	struct fd_host *fd_host = hba->hba_ptr;

  	pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"

  		" Target Core
  ", hba->hba_id, fd_host->fd_host_id);
  
  	kfree(fd_host);
  	hba->hba_ptr = NULL;
  }

  static struct se_device *fd_alloc_device(struct se_hba *hba, const char *name)

  {
  	struct fd_dev *fd_dev;

  	struct fd_host *fd_host = hba->hba_ptr;

  
  	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);

  	if (!fd_dev) {
  		pr_err("Unable to allocate memory for struct fd_dev
  ");

  		return NULL;
  	}
  
  	fd_dev->fd_host = fd_host;

  	pr_debug("FILEIO: Allocated fd_dev for %p
  ", name);

  	return &fd_dev->dev;

  }

  static int fd_configure_device(struct se_device *dev)

  {

  	struct fd_dev *fd_dev = FD_DEV(dev);
  	struct fd_host *fd_host = dev->se_hba->hba_ptr;

  	struct file *file;
  	struct inode *inode = NULL;

  	int flags, ret = -EINVAL;

  	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
  		pr_err("Missing fd_dev_name=
  ");
  		return -EINVAL;
  	}

  	/*

  	 * Use O_DSYNC by default instead of O_SYNC to forgo syncing
  	 * of pure timestamp updates.

  	 */

  	flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;

  	/*
  	 * Optionally allow fd_buffered_io=1 to be enabled for people
  	 * who want use the fs buffer cache as an WriteCache mechanism.
  	 *
  	 * This means that in event of a hard failure, there is a risk
  	 * of silent data-loss if the SCSI client has *not* performed a
  	 * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
  	 * to write-out the entire device cache.
  	 */
  	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
  		pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO
  ");
  		flags &= ~O_DSYNC;
  	}

  	file = filp_open(fd_dev->fd_dev_name, flags, 0600);

  	if (IS_ERR(file)) {

  		pr_err("filp_open(%s) failed
  ", fd_dev->fd_dev_name);

  		ret = PTR_ERR(file);
  		goto fail;
  	}

  	fd_dev->fd_file = file;
  	/*
  	 * If using a block backend with this struct file, we extract
  	 * fd_dev->fd_[block,dev]_size from struct block_device.
  	 *
  	 * Otherwise, we use the passed fd_size= from configfs
  	 */
  	inode = file->f_mapping->host;
  	if (S_ISBLK(inode->i_mode)) {

  		struct request_queue *q = bdev_get_queue(inode->i_bdev);

  		unsigned long long dev_size;

  		fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);

  		/*
  		 * Determine the number of bytes from i_size_read() minus
  		 * one (1) logical sector from underlying struct block_device
  		 */

  		dev_size = (i_size_read(file->f_mapping->host) -

  				       fd_dev->fd_block_size);

  		pr_debug("FILEIO: Using size: %llu bytes from struct"

  			" block_device blocks: %llu logical_block_size: %d
  ",

  			dev_size, div_u64(dev_size, fd_dev->fd_block_size),

  			fd_dev->fd_block_size);

  		if (target_configure_unmap_from_queue(&dev->dev_attrib, q))

  			pr_debug("IFILE: BLOCK Discard support available,"

  				 " disabled by default
  ");

  		/*
  		 * Enable write same emulation for IBLOCK and use 0xFFFF as
  		 * the smaller WRITE_SAME(10) only has a two-byte block count.
  		 */
  		dev->dev_attrib.max_write_same_len = 0xFFFF;

  
  		if (blk_queue_nonrot(q))
  			dev->dev_attrib.is_nonrot = 1;

  	} else {
  		if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {

  			pr_err("FILEIO: Missing fd_dev_size="

  				" parameter, and no backing struct"
  				" block_device
  ");
  			goto fail;
  		}

  		fd_dev->fd_block_size = FD_BLOCKSIZE;

  		/*
  		 * Limit UNMAP emulation to 8k Number of LBAs (NoLB)
  		 */
  		dev->dev_attrib.max_unmap_lba_count = 0x2000;
  		/*
  		 * Currently hardcoded to 1 in Linux/SCSI code..
  		 */
  		dev->dev_attrib.max_unmap_block_desc_count = 1;
  		dev->dev_attrib.unmap_granularity = 1;
  		dev->dev_attrib.unmap_granularity_alignment = 0;
  
  		/*
  		 * Limit WRITE_SAME w/ UNMAP=0 emulation to 8k Number of LBAs (NoLB)
  		 * based upon struct iovec limit for vfs_writev()
  		 */
  		dev->dev_attrib.max_write_same_len = 0x1000;

  	}

  	dev->dev_attrib.hw_block_size = fd_dev->fd_block_size;

  	dev->dev_attrib.max_bytes_per_io = FD_MAX_BYTES;
  	dev->dev_attrib.hw_max_sectors = FD_MAX_BYTES / fd_dev->fd_block_size;

  	dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;

  	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
  		pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
  			" with FDBD_HAS_BUFFERED_IO_WCE
  ");

  		dev->dev_attrib.emulate_write_cache = 1;

  	}

  	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
  	fd_dev->fd_queue_depth = dev->queue_depth;

  	pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"

  		" %llu total bytes
  ", fd_host->fd_host_id, fd_dev->fd_dev_id,
  			fd_dev->fd_dev_name, fd_dev->fd_dev_size);

  	return 0;

  fail:
  	if (fd_dev->fd_file) {
  		filp_close(fd_dev->fd_file, NULL);
  		fd_dev->fd_file = NULL;
  	}

  	return ret;

  }

  static void fd_dev_call_rcu(struct rcu_head *p)

  {

  	struct se_device *dev = container_of(p, struct se_device, rcu_head);

  	struct fd_dev *fd_dev = FD_DEV(dev);

  	kfree(fd_dev);
  }

  static void fd_free_device(struct se_device *dev)

  {

  	struct fd_dev *fd_dev = FD_DEV(dev);

  	if (fd_dev->fd_file) {
  		filp_close(fd_dev->fd_file, NULL);
  		fd_dev->fd_file = NULL;

  	}

  	call_rcu(&dev->rcu_head, fd_dev_call_rcu);

  }

  static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
  		    u32 block_size, struct scatterlist *sgl,
  		    u32 sgl_nents, u32 data_length, int is_write)

  {

  	struct scatterlist *sg;

  	struct iov_iter iter;
  	struct bio_vec *bvec;
  	ssize_t len = 0;

  	loff_t pos = (cmd->t_task_lba * block_size);

  	int ret = 0, i;

  	bvec = kcalloc(sgl_nents, sizeof(struct bio_vec), GFP_KERNEL);
  	if (!bvec) {

  		pr_err("Unable to allocate fd_do_readv iov[]
  ");

  		return -ENOMEM;

  	}

  	for_each_sg(sgl, sg, sgl_nents, i) {

  		bvec[i].bv_page = sg_page(sg);
  		bvec[i].bv_len = sg->length;
  		bvec[i].bv_offset = sg->offset;

  		len += sg->length;
  	}

  	iov_iter_bvec(&iter, ITER_BVEC, bvec, sgl_nents, len);

  	if (is_write)

  		ret = vfs_iter_write(fd, &iter, &pos);

  	else

  		ret = vfs_iter_read(fd, &iter, &pos);

  	kfree(bvec);

  
  	if (is_write) {

  		if (ret < 0 || ret != data_length) {

  			pr_err("%s() write returned %d
  ", __func__, ret);

  			return (ret < 0 ? ret : -EINVAL);

  		}
  	} else {

  		/*
  		 * Return zeros and GOOD status even if the READ did not return
  		 * the expected virt_size for struct file w/o a backing struct
  		 * block_device.
  		 */

  		if (S_ISBLK(file_inode(fd)->i_mode)) {

  			if (ret < 0 || ret != data_length) {

  				pr_err("%s() returned %d, expecting %u for "
  						"S_ISBLK
  ", __func__, ret,

  						data_length);

  				return (ret < 0 ? ret : -EINVAL);
  			}
  		} else {
  			if (ret < 0) {
  				pr_err("%s() returned %d for non S_ISBLK
  ",
  						__func__, ret);
  				return ret;
  			}

  		}
  	}

  	return 1;
  }

  static sense_reason_t
  fd_execute_sync_cache(struct se_cmd *cmd)

  {

  	struct se_device *dev = cmd->se_dev;

  	struct fd_dev *fd_dev = FD_DEV(dev);

  	int immed = (cmd->t_task_cdb[1] & 0x2);

  	loff_t start, end;
  	int ret;
  
  	/*
  	 * If the Immediate bit is set, queue up the GOOD response
  	 * for this SYNCHRONIZE_CACHE op
  	 */
  	if (immed)

  		target_complete_cmd(cmd, SAM_STAT_GOOD);

  
  	/*
  	 * Determine if we will be flushing the entire device.
  	 */

  	if (cmd->t_task_lba == 0 && cmd->data_length == 0) {

  		start = 0;
  		end = LLONG_MAX;
  	} else {

  		start = cmd->t_task_lba * dev->dev_attrib.block_size;

  		if (cmd->data_length)

  			end = start + cmd->data_length - 1;

  		else
  			end = LLONG_MAX;
  	}
  
  	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
  	if (ret != 0)

  		pr_err("FILEIO: vfs_fsync_range() failed: %d
  ", ret);

  	if (immed)

  		return 0;

  	if (ret)

  		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);

  	else

  		target_complete_cmd(cmd, SAM_STAT_GOOD);

  
  	return 0;

  }

  static sense_reason_t
  fd_execute_write_same(struct se_cmd *cmd)
  {
  	struct se_device *se_dev = cmd->se_dev;
  	struct fd_dev *fd_dev = FD_DEV(se_dev);

  	loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;

  	sector_t nolb = sbc_get_write_same_sectors(cmd);
  	struct iov_iter iter;
  	struct bio_vec *bvec;
  	unsigned int len = 0, i;
  	ssize_t ret;

  
  	if (!nolb) {
  		target_complete_cmd(cmd, SAM_STAT_GOOD);
  		return 0;
  	}

  	if (cmd->prot_op) {
  		pr_err("WRITE_SAME: Protection information with FILEIO"
  		       " backends not supported
  ");
  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  	}

  
  	if (cmd->t_data_nents > 1 ||

  	    cmd->t_data_sg[0].length != cmd->se_dev->dev_attrib.block_size) {

  		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"

  			" block_size: %u
  ",
  			cmd->t_data_nents,
  			cmd->t_data_sg[0].length,

  			cmd->se_dev->dev_attrib.block_size);
  		return TCM_INVALID_CDB_FIELD;
  	}

  	bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
  	if (!bvec)

  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

  	for (i = 0; i < nolb; i++) {
  		bvec[i].bv_page = sg_page(&cmd->t_data_sg[0]);
  		bvec[i].bv_len = cmd->t_data_sg[0].length;
  		bvec[i].bv_offset = cmd->t_data_sg[0].offset;

  		len += se_dev->dev_attrib.block_size;
  	}

  	iov_iter_bvec(&iter, ITER_BVEC, bvec, nolb, len);
  	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos);

  	kfree(bvec);
  	if (ret < 0 || ret != len) {
  		pr_err("vfs_iter_write() returned %zd for write same
  ", ret);

  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  	}
  
  	target_complete_cmd(cmd, SAM_STAT_GOOD);
  	return 0;
  }

  static int
  fd_do_prot_fill(struct se_device *se_dev, sector_t lba, sector_t nolb,
  		void *buf, size_t bufsize)
  {
  	struct fd_dev *fd_dev = FD_DEV(se_dev);
  	struct file *prot_fd = fd_dev->fd_prot_file;
  	sector_t prot_length, prot;
  	loff_t pos = lba * se_dev->prot_length;
  
  	if (!prot_fd) {
  		pr_err("Unable to locate fd_dev->fd_prot_file
  ");
  		return -ENODEV;
  	}
  
  	prot_length = nolb * se_dev->prot_length;
  
  	for (prot = 0; prot < prot_length;) {
  		sector_t len = min_t(sector_t, bufsize, prot_length - prot);
  		ssize_t ret = kernel_write(prot_fd, buf, len, pos + prot);
  
  		if (ret != len) {
  			pr_err("vfs_write to prot file failed: %zd
  ", ret);
  			return ret < 0 ? ret : -ENODEV;
  		}
  		prot += ret;
  	}
  
  	return 0;
  }
  
  static int
  fd_do_prot_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
  {
  	void *buf;
  	int rc;
  
  	buf = (void *)__get_free_page(GFP_KERNEL);
  	if (!buf) {
  		pr_err("Unable to allocate FILEIO prot buf
  ");
  		return -ENOMEM;
  	}
  	memset(buf, 0xff, PAGE_SIZE);
  
  	rc = fd_do_prot_fill(cmd->se_dev, lba, nolb, buf, PAGE_SIZE);
  
  	free_page((unsigned long)buf);
  
  	return rc;
  }

  static sense_reason_t

  fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)

  {

  	struct file *file = FD_DEV(cmd->se_dev)->fd_file;

  	struct inode *inode = file->f_mapping->host;

  	int ret;

  	if (cmd->se_dev->dev_attrib.pi_prot_type) {
  		ret = fd_do_prot_unmap(cmd, lba, nolb);
  		if (ret)
  			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  	}

  	if (S_ISBLK(inode->i_mode)) {
  		/* The backend is block device, use discard */
  		struct block_device *bdev = inode->i_bdev;

  		struct se_device *dev = cmd->se_dev;

  		ret = blkdev_issue_discard(bdev,
  					   target_to_linux_sector(dev, lba),
  					   target_to_linux_sector(dev,  nolb),
  					   GFP_KERNEL, 0);

  		if (ret < 0) {
  			pr_warn("FILEIO: blkdev_issue_discard() failed: %d
  ",
  				ret);
  			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  		}
  	} else {
  		/* The backend is normal file, use fallocate */

  		struct se_device *se_dev = cmd->se_dev;
  		loff_t pos = lba * se_dev->dev_attrib.block_size;

  		unsigned int len = nolb * se_dev->dev_attrib.block_size;
  		int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
  
  		if (!file->f_op->fallocate)
  			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  
  		ret = file->f_op->fallocate(file, mode, pos, len);
  		if (ret < 0) {
  			pr_warn("FILEIO: fallocate() failed: %d
  ", ret);
  			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  		}
  	}

  	return 0;
  }
  
  static sense_reason_t

  fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
  	      enum dma_data_direction data_direction)

  {

  	struct se_device *dev = cmd->se_dev;

  	struct fd_dev *fd_dev = FD_DEV(dev);
  	struct file *file = fd_dev->fd_file;
  	struct file *pfile = fd_dev->fd_prot_file;

  	sense_reason_t rc;

  	int ret = 0;

  	/*
  	 * We are currently limited by the number of iovecs (2048) per
  	 * single vfs_[writev,readv] call.
  	 */
  	if (cmd->data_length > FD_MAX_BYTES) {
  		pr_err("FILEIO: Not able to process I/O of %u bytes due to"

  		       "FD_MAX_BYTES: %u iovec count limitation
  ",

  			cmd->data_length, FD_MAX_BYTES);
  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  	}

  	/*
  	 * Call vectorized fileio functions to map struct scatterlist
  	 * physical memory addresses to struct iovec virtual memory.
  	 */

  	if (data_direction == DMA_FROM_DEVICE) {

  		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {

  			ret = fd_do_rw(cmd, pfile, dev->prot_length,
  				       cmd->t_prot_sg, cmd->t_prot_nents,
  				       cmd->prot_length, 0);

  			if (ret < 0)
  				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  		}

  		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
  			       sgl, sgl_nents, cmd->data_length, 0);

  		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {

  			u32 sectors = cmd->data_length >>
  					ilog2(dev->dev_attrib.block_size);

  			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,

  					    0, cmd->t_prot_sg, 0);
  			if (rc)

  				return rc;

  		}

  	} else {

  		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {

  			u32 sectors = cmd->data_length >>
  					ilog2(dev->dev_attrib.block_size);

  			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
  					    0, cmd->t_prot_sg, 0);

  			if (rc)

  				return rc;

  		}

  		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
  			       sgl, sgl_nents, cmd->data_length, 1);

  		/*

  		 * Perform implicit vfs_fsync_range() for fd_do_writev() ops

  		 * for SCSI WRITEs with Forced Unit Access (FUA) set.
  		 * Allow this to happen independent of WCE=0 setting.
  		 */

  		if (ret > 0 && (cmd->se_cmd_flags & SCF_FUA)) {

  			loff_t start = cmd->t_task_lba *

  				dev->dev_attrib.block_size;

  			loff_t end;
  
  			if (cmd->data_length)
  				end = start + cmd->data_length - 1;
  			else
  				end = LLONG_MAX;

  			vfs_fsync_range(fd_dev->fd_file, start, end, 1);
  		}

  		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {

  			ret = fd_do_rw(cmd, pfile, dev->prot_length,
  				       cmd->t_prot_sg, cmd->t_prot_nents,
  				       cmd->prot_length, 1);

  			if (ret < 0)
  				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  		}

  	}

  	if (ret < 0)

  		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

  	if (ret)
  		target_complete_cmd(cmd, SAM_STAT_GOOD);

  	return 0;

  }

  enum {
  	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
  };
  
  static match_table_t tokens = {
  	{Opt_fd_dev_name, "fd_dev_name=%s"},
  	{Opt_fd_dev_size, "fd_dev_size=%s"},

  	{Opt_fd_buffered_io, "fd_buffered_io=%d"},

  	{Opt_err, NULL}
  };

  static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
  		const char *page, ssize_t count)

  {

  	struct fd_dev *fd_dev = FD_DEV(dev);

  	char *orig, *ptr, *arg_p, *opts;
  	substring_t args[MAX_OPT_ARGS];

  	int ret = 0, arg, token;

  
  	opts = kstrdup(page, GFP_KERNEL);
  	if (!opts)
  		return -ENOMEM;
  
  	orig = opts;

  	while ((ptr = strsep(&opts, ",
  ")) != NULL) {

  		if (!*ptr)
  			continue;
  
  		token = match_token(ptr, tokens, args);
  		switch (token) {
  		case Opt_fd_dev_name:

  			if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
  				FD_MAX_DEV_NAME) == 0) {
  				ret = -EINVAL;

  				break;
  			}

  			pr_debug("FILEIO: Referencing Path: %s
  ",

  					fd_dev->fd_dev_name);
  			fd_dev->fbd_flags |= FBDF_HAS_PATH;
  			break;
  		case Opt_fd_dev_size:
  			arg_p = match_strdup(&args[0]);

  			if (!arg_p) {
  				ret = -ENOMEM;
  				break;
  			}

  			ret = kstrtoull(arg_p, 0, &fd_dev->fd_dev_size);

  			kfree(arg_p);

  			if (ret < 0) {

  				pr_err("kstrtoull() failed for"

  						" fd_dev_size=
  ");
  				goto out;
  			}

  			pr_debug("FILEIO: Referencing Size: %llu"

  					" bytes
  ", fd_dev->fd_dev_size);
  			fd_dev->fbd_flags |= FBDF_HAS_SIZE;
  			break;

  		case Opt_fd_buffered_io:

  			ret = match_int(args, &arg);
  			if (ret)
  				goto out;

  			if (arg != 1) {
  				pr_err("bogus fd_buffered_io=%d value
  ", arg);
  				ret = -EINVAL;
  				goto out;
  			}
  
  			pr_debug("FILEIO: Using buffered I/O"
  				" operations for struct fd_dev
  ");
  
  			fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
  			break;

  		default:
  			break;
  		}
  	}
  
  out:
  	kfree(orig);
  	return (!ret) ? count : ret;
  }

  static ssize_t fd_show_configfs_dev_params(struct se_device *dev, char *b)

  {

  	struct fd_dev *fd_dev = FD_DEV(dev);

  	ssize_t bl = 0;
  
  	bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);

  	bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s
  ",
  		fd_dev->fd_dev_name, fd_dev->fd_dev_size,
  		(fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
  		"Buffered-WCE" : "O_DSYNC");

  	return bl;
  }

  static sector_t fd_get_blocks(struct se_device *dev)
  {

  	struct fd_dev *fd_dev = FD_DEV(dev);

  	struct file *f = fd_dev->fd_file;
  	struct inode *i = f->f_mapping->host;
  	unsigned long long dev_size;
  	/*
  	 * When using a file that references an underlying struct block_device,
  	 * ensure dev_size is always based on the current inode size in order
  	 * to handle underlying block_device resize operations.
  	 */
  	if (S_ISBLK(i->i_mode))

  		dev_size = i_size_read(i);

  	else
  		dev_size = fd_dev->fd_dev_size;

  	return div_u64(dev_size - dev->dev_attrib.block_size,
  		       dev->dev_attrib.block_size);

  }

  static int fd_init_prot(struct se_device *dev)
  {
  	struct fd_dev *fd_dev = FD_DEV(dev);
  	struct file *prot_file, *file = fd_dev->fd_file;
  	struct inode *inode;
  	int ret, flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
  	char buf[FD_MAX_DEV_PROT_NAME];
  
  	if (!file) {
  		pr_err("Unable to locate fd_dev->fd_file
  ");
  		return -ENODEV;
  	}
  
  	inode = file->f_mapping->host;
  	if (S_ISBLK(inode->i_mode)) {
  		pr_err("FILEIO Protection emulation only supported on"
  		       " !S_ISBLK
  ");
  		return -ENOSYS;
  	}
  
  	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE)
  		flags &= ~O_DSYNC;
  
  	snprintf(buf, FD_MAX_DEV_PROT_NAME, "%s.protection",
  		 fd_dev->fd_dev_name);
  
  	prot_file = filp_open(buf, flags, 0600);
  	if (IS_ERR(prot_file)) {
  		pr_err("filp_open(%s) failed
  ", buf);
  		ret = PTR_ERR(prot_file);
  		return ret;
  	}
  	fd_dev->fd_prot_file = prot_file;
  
  	return 0;
  }

  static int fd_format_prot(struct se_device *dev)
  {

  	unsigned char *buf;

  	int unit_size = FDBD_FORMAT_UNIT_SIZE * dev->dev_attrib.block_size;

  	int ret;

  
  	if (!dev->dev_attrib.pi_prot_type) {
  		pr_err("Unable to format_prot while pi_prot_type == 0
  ");
  		return -ENODEV;
  	}

  	buf = vzalloc(unit_size);
  	if (!buf) {
  		pr_err("Unable to allocate FILEIO prot buf
  ");
  		return -ENOMEM;
  	}

  
  	pr_debug("Using FILEIO prot_length: %llu
  ",

  		 (unsigned long long)(dev->transport->get_blocks(dev) + 1) *
  					dev->prot_length);

  	memset(buf, 0xff, unit_size);

  	ret = fd_do_prot_fill(dev, 0, dev->transport->get_blocks(dev) + 1,
  			      buf, unit_size);

  	vfree(buf);
  	return ret;
  }
  
  static void fd_free_prot(struct se_device *dev)
  {
  	struct fd_dev *fd_dev = FD_DEV(dev);
  
  	if (!fd_dev->fd_prot_file)
  		return;
  
  	filp_close(fd_dev->fd_prot_file, NULL);
  	fd_dev->fd_prot_file = NULL;
  }

  static struct sbc_ops fd_sbc_ops = {

  	.execute_rw		= fd_execute_rw,

  	.execute_sync_cache	= fd_execute_sync_cache,

  	.execute_write_same	= fd_execute_write_same,

  	.execute_unmap		= fd_execute_unmap,

  };

  static sense_reason_t
  fd_parse_cdb(struct se_cmd *cmd)

  {

  	return sbc_parse_cdb(cmd, &fd_sbc_ops);

  }

  static const struct target_backend_ops fileio_ops = {

  	.name			= "fileio",

  	.inquiry_prod		= "FILEIO",
  	.inquiry_rev		= FD_VERSION,

  	.owner			= THIS_MODULE,

  	.attach_hba		= fd_attach_hba,
  	.detach_hba		= fd_detach_hba,

  	.alloc_device		= fd_alloc_device,
  	.configure_device	= fd_configure_device,

  	.free_device		= fd_free_device,

  	.parse_cdb		= fd_parse_cdb,

  	.set_configfs_dev_params = fd_set_configfs_dev_params,
  	.show_configfs_dev_params = fd_show_configfs_dev_params,

  	.get_device_type	= sbc_get_device_type,

  	.get_blocks		= fd_get_blocks,

  	.init_prot		= fd_init_prot,
  	.format_prot		= fd_format_prot,
  	.free_prot		= fd_free_prot,

  	.tb_dev_attrib_attrs	= sbc_attrib_attrs,

  };
  
  static int __init fileio_module_init(void)
  {

  	return transport_backend_register(&fileio_ops);

  }

  static void __exit fileio_module_exit(void)

  {

  	target_backend_unregister(&fileio_ops);

  }
  
  MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
  MODULE_AUTHOR("nab@Linux-iSCSI.org");
  MODULE_LICENSE("GPL");
  
  module_init(fileio_module_init);
  module_exit(fileio_module_exit);