path: root/drivers/target/target_core_file.c

/*******************************************************************************
 * 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/falloc.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.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);
}

/*	fd_attach_hba(): (Part of se_subsystem_api_t template)
 *
 *
 */
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\n");
		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\n", hba->hba_id, FD_VERSION,
		TARGET_CORE_MOD_VERSION);
	pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic\n",
		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\n", 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\n");
		return NULL;
	}

	fd_dev->fd_host = fd_host;

	pr_debug("FILEIO: Allocated fd_dev for %p\n", 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=\n");
		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\n");
		flags &= ~O_DSYNC;
	}

	file = filp_open(fd_dev->fd_dev_name, flags, 0600);
	if (IS_ERR(file)) {
		pr_err("filp_open(%s) failed\n", 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\n",
			dev_size, div_u64(dev_size, fd_dev->fd_block_size),
			fd_dev->fd_block_size);
		/*
		 * Check if the underlying struct block_device request_queue supports