xref: /linux/drivers/target/target_core_file.c (revision e58e871becec2d3b04ed91c0c16fe8deac9c9dfa)
1 /*******************************************************************************
2  * Filename:  target_core_file.c
3  *
4  * This file contains the Storage Engine <-> FILEIO transport specific functions
5  *
6  * (c) Copyright 2005-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/string.h>
27 #include <linux/parser.h>
28 #include <linux/timer.h>
29 #include <linux/blkdev.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/module.h>
33 #include <linux/vmalloc.h>
34 #include <linux/falloc.h>
35 #include <linux/uio.h>
36 #include <scsi/scsi_proto.h>
37 #include <asm/unaligned.h>
38 
39 #include <target/target_core_base.h>
40 #include <target/target_core_backend.h>
41 
42 #include "target_core_file.h"
43 
44 static inline struct fd_dev *FD_DEV(struct se_device *dev)
45 {
46 	return container_of(dev, struct fd_dev, dev);
47 }
48 
49 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
50 {
51 	struct fd_host *fd_host;
52 
53 	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
54 	if (!fd_host) {
55 		pr_err("Unable to allocate memory for struct fd_host\n");
56 		return -ENOMEM;
57 	}
58 
59 	fd_host->fd_host_id = host_id;
60 
61 	hba->hba_ptr = fd_host;
62 
63 	pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
64 		" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
65 		TARGET_CORE_VERSION);
66 	pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic\n",
67 		hba->hba_id, fd_host->fd_host_id);
68 
69 	return 0;
70 }
71 
72 static void fd_detach_hba(struct se_hba *hba)
73 {
74 	struct fd_host *fd_host = hba->hba_ptr;
75 
76 	pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
77 		" Target Core\n", hba->hba_id, fd_host->fd_host_id);
78 
79 	kfree(fd_host);
80 	hba->hba_ptr = NULL;
81 }
82 
83 static struct se_device *fd_alloc_device(struct se_hba *hba, const char *name)
84 {
85 	struct fd_dev *fd_dev;
86 	struct fd_host *fd_host = hba->hba_ptr;
87 
88 	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
89 	if (!fd_dev) {
90 		pr_err("Unable to allocate memory for struct fd_dev\n");
91 		return NULL;
92 	}
93 
94 	fd_dev->fd_host = fd_host;
95 
96 	pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
97 
98 	return &fd_dev->dev;
99 }
100 
101 static int fd_configure_device(struct se_device *dev)
102 {
103 	struct fd_dev *fd_dev = FD_DEV(dev);
104 	struct fd_host *fd_host = dev->se_hba->hba_ptr;
105 	struct file *file;
106 	struct inode *inode = NULL;
107 	int flags, ret = -EINVAL;
108 
109 	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
110 		pr_err("Missing fd_dev_name=\n");
111 		return -EINVAL;
112 	}
113 
114 	/*
115 	 * Use O_DSYNC by default instead of O_SYNC to forgo syncing
116 	 * of pure timestamp updates.
117 	 */
118 	flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
119 
120 	/*
121 	 * Optionally allow fd_buffered_io=1 to be enabled for people
122 	 * who want use the fs buffer cache as an WriteCache mechanism.
123 	 *
124 	 * This means that in event of a hard failure, there is a risk
125 	 * of silent data-loss if the SCSI client has *not* performed a
126 	 * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
127 	 * to write-out the entire device cache.
128 	 */
129 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
130 		pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
131 		flags &= ~O_DSYNC;
132 	}
133 
134 	file = filp_open(fd_dev->fd_dev_name, flags, 0600);
135 	if (IS_ERR(file)) {
136 		pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
137 		ret = PTR_ERR(file);
138 		goto fail;
139 	}
140 	fd_dev->fd_file = file;
141 	/*
142 	 * If using a block backend with this struct file, we extract
143 	 * fd_dev->fd_[block,dev]_size from struct block_device.
144 	 *
145 	 * Otherwise, we use the passed fd_size= from configfs
146 	 */
147 	inode = file->f_mapping->host;
148 	if (S_ISBLK(inode->i_mode)) {
149 		struct request_queue *q = bdev_get_queue(inode->i_bdev);
150 		unsigned long long dev_size;
151 
152 		fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
153 		/*
154 		 * Determine the number of bytes from i_size_read() minus
155 		 * one (1) logical sector from underlying struct block_device
156 		 */
157 		dev_size = (i_size_read(file->f_mapping->host) -
158 				       fd_dev->fd_block_size);
159 
160 		pr_debug("FILEIO: Using size: %llu bytes from struct"
161 			" block_device blocks: %llu logical_block_size: %d\n",
162 			dev_size, div_u64(dev_size, fd_dev->fd_block_size),
163 			fd_dev->fd_block_size);
164 
165 		if (target_configure_unmap_from_queue(&dev->dev_attrib, q))
166 			pr_debug("IFILE: BLOCK Discard support available,"
167 				 " disabled by default\n");
168 		/*
169 		 * Enable write same emulation for IBLOCK and use 0xFFFF as
170 		 * the smaller WRITE_SAME(10) only has a two-byte block count.
171 		 */
172 		dev->dev_attrib.max_write_same_len = 0xFFFF;
173 
174 		if (blk_queue_nonrot(q))
175 			dev->dev_attrib.is_nonrot = 1;
176 	} else {
177 		if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
178 			pr_err("FILEIO: Missing fd_dev_size="
179 				" parameter, and no backing struct"
180 				" block_device\n");
181 			goto fail;
182 		}
183 
184 		fd_dev->fd_block_size = FD_BLOCKSIZE;
185 		/*
186 		 * Limit UNMAP emulation to 8k Number of LBAs (NoLB)
187 		 */
188 		dev->dev_attrib.max_unmap_lba_count = 0x2000;
189 		/*
190 		 * Currently hardcoded to 1 in Linux/SCSI code..
191 		 */
192 		dev->dev_attrib.max_unmap_block_desc_count = 1;
193 		dev->dev_attrib.unmap_granularity = 1;
194 		dev->dev_attrib.unmap_granularity_alignment = 0;
195 
196 		/*
197 		 * Limit WRITE_SAME w/ UNMAP=0 emulation to 8k Number of LBAs (NoLB)
198 		 * based upon struct iovec limit for vfs_writev()
199 		 */
200 		dev->dev_attrib.max_write_same_len = 0x1000;
201 	}
202 
203 	dev->dev_attrib.hw_block_size = fd_dev->fd_block_size;
204 	dev->dev_attrib.max_bytes_per_io = FD_MAX_BYTES;
205 	dev->dev_attrib.hw_max_sectors = FD_MAX_BYTES / fd_dev->fd_block_size;
206 	dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
207 
208 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
209 		pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
210 			" with FDBD_HAS_BUFFERED_IO_WCE\n");
211 		dev->dev_attrib.emulate_write_cache = 1;
212 	}
213 
214 	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
215 	fd_dev->fd_queue_depth = dev->queue_depth;
216 
217 	pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
218 		" %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
219 			fd_dev->fd_dev_name, fd_dev->fd_dev_size);
220 
221 	return 0;
222 fail:
223 	if (fd_dev->fd_file) {
224 		filp_close(fd_dev->fd_file, NULL);
225 		fd_dev->fd_file = NULL;
226 	}
227 	return ret;
228 }
229 
230 static void fd_dev_call_rcu(struct rcu_head *p)
231 {
232 	struct se_device *dev = container_of(p, struct se_device, rcu_head);
233 	struct fd_dev *fd_dev = FD_DEV(dev);
234 
235 	kfree(fd_dev);
236 }
237 
238 static void fd_free_device(struct se_device *dev)
239 {
240 	struct fd_dev *fd_dev = FD_DEV(dev);
241 
242 	if (fd_dev->fd_file) {
243 		filp_close(fd_dev->fd_file, NULL);
244 		fd_dev->fd_file = NULL;
245 	}
246 	call_rcu(&dev->rcu_head, fd_dev_call_rcu);
247 }
248 
249 static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
250 		    u32 block_size, struct scatterlist *sgl,
251 		    u32 sgl_nents, u32 data_length, int is_write)
252 {
253 	struct scatterlist *sg;
254 	struct iov_iter iter;
255 	struct bio_vec *bvec;
256 	ssize_t len = 0;
257 	loff_t pos = (cmd->t_task_lba * block_size);
258 	int ret = 0, i;
259 
260 	bvec = kcalloc(sgl_nents, sizeof(struct bio_vec), GFP_KERNEL);
261 	if (!bvec) {
262 		pr_err("Unable to allocate fd_do_readv iov[]\n");
263 		return -ENOMEM;
264 	}
265 
266 	for_each_sg(sgl, sg, sgl_nents, i) {
267 		bvec[i].bv_page = sg_page(sg);
268 		bvec[i].bv_len = sg->length;
269 		bvec[i].bv_offset = sg->offset;
270 
271 		len += sg->length;
272 	}
273 
274 	iov_iter_bvec(&iter, ITER_BVEC, bvec, sgl_nents, len);
275 	if (is_write)
276 		ret = vfs_iter_write(fd, &iter, &pos);
277 	else
278 		ret = vfs_iter_read(fd, &iter, &pos);
279 
280 	if (is_write) {
281 		if (ret < 0 || ret != data_length) {
282 			pr_err("%s() write returned %d\n", __func__, ret);
283 			if (ret >= 0)
284 				ret = -EINVAL;
285 		}
286 	} else {
287 		/*
288 		 * Return zeros and GOOD status even if the READ did not return
289 		 * the expected virt_size for struct file w/o a backing struct
290 		 * block_device.
291 		 */
292 		if (S_ISBLK(file_inode(fd)->i_mode)) {
293 			if (ret < 0 || ret != data_length) {
294 				pr_err("%s() returned %d, expecting %u for "
295 						"S_ISBLK\n", __func__, ret,
296 						data_length);
297 				if (ret >= 0)
298 					ret = -EINVAL;
299 			}
300 		} else {
301 			if (ret < 0) {
302 				pr_err("%s() returned %d for non S_ISBLK\n",
303 						__func__, ret);
304 			} else if (ret != data_length) {
305 				/*
306 				 * Short read case:
307 				 * Probably some one truncate file under us.
308 				 * We must explicitly zero sg-pages to prevent
309 				 * expose uninizialized pages to userspace.
310 				 */
311 				if (ret < data_length)
312 					ret += iov_iter_zero(data_length - ret, &iter);
313 				else
314 					ret = -EINVAL;
315 			}
316 		}
317 	}
318 	kfree(bvec);
319 	return ret;
320 }
321 
322 static sense_reason_t
323 fd_execute_sync_cache(struct se_cmd *cmd)
324 {
325 	struct se_device *dev = cmd->se_dev;
326 	struct fd_dev *fd_dev = FD_DEV(dev);
327 	int immed = (cmd->t_task_cdb[1] & 0x2);
328 	loff_t start, end;
329 	int ret;
330 
331 	/*
332 	 * If the Immediate bit is set, queue up the GOOD response
333 	 * for this SYNCHRONIZE_CACHE op
334 	 */
335 	if (immed)
336 		target_complete_cmd(cmd, SAM_STAT_GOOD);
337 
338 	/*
339 	 * Determine if we will be flushing the entire device.
340 	 */
341 	if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
342 		start = 0;
343 		end = LLONG_MAX;
344 	} else {
345 		start = cmd->t_task_lba * dev->dev_attrib.block_size;
346 		if (cmd->data_length)
347 			end = start + cmd->data_length - 1;
348 		else
349 			end = LLONG_MAX;
350 	}
351 
352 	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
353 	if (ret != 0)
354 		pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
355 
356 	if (immed)
357 		return 0;
358 
359 	if (ret)
360 		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
361 	else
362 		target_complete_cmd(cmd, SAM_STAT_GOOD);
363 
364 	return 0;
365 }
366 
367 static sense_reason_t
368 fd_execute_write_same(struct se_cmd *cmd)
369 {
370 	struct se_device *se_dev = cmd->se_dev;
371 	struct fd_dev *fd_dev = FD_DEV(se_dev);
372 	loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;
373 	sector_t nolb = sbc_get_write_same_sectors(cmd);
374 	struct iov_iter iter;
375 	struct bio_vec *bvec;
376 	unsigned int len = 0, i;
377 	ssize_t ret;
378 
379 	if (!nolb) {
380 		target_complete_cmd(cmd, SAM_STAT_GOOD);
381 		return 0;
382 	}
383 	if (cmd->prot_op) {
384 		pr_err("WRITE_SAME: Protection information with FILEIO"
385 		       " backends not supported\n");
386 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
387 	}
388 
389 	if (cmd->t_data_nents > 1 ||
390 	    cmd->t_data_sg[0].length != cmd->se_dev->dev_attrib.block_size) {
391 		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
392 			" block_size: %u\n",
393 			cmd->t_data_nents,
394 			cmd->t_data_sg[0].length,
395 			cmd->se_dev->dev_attrib.block_size);
396 		return TCM_INVALID_CDB_FIELD;
397 	}
398 
399 	bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
400 	if (!bvec)
401 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
402 
403 	for (i = 0; i < nolb; i++) {
404 		bvec[i].bv_page = sg_page(&cmd->t_data_sg[0]);
405 		bvec[i].bv_len = cmd->t_data_sg[0].length;
406 		bvec[i].bv_offset = cmd->t_data_sg[0].offset;
407 
408 		len += se_dev->dev_attrib.block_size;
409 	}
410 
411 	iov_iter_bvec(&iter, ITER_BVEC, bvec, nolb, len);
412 	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos);
413 
414 	kfree(bvec);
415 	if (ret < 0 || ret != len) {
416 		pr_err("vfs_iter_write() returned %zd for write same\n", ret);
417 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
418 	}
419 
420 	target_complete_cmd(cmd, SAM_STAT_GOOD);
421 	return 0;
422 }
423 
424 static int
425 fd_do_prot_fill(struct se_device *se_dev, sector_t lba, sector_t nolb,
426 		void *buf, size_t bufsize)
427 {
428 	struct fd_dev *fd_dev = FD_DEV(se_dev);
429 	struct file *prot_fd = fd_dev->fd_prot_file;
430 	sector_t prot_length, prot;
431 	loff_t pos = lba * se_dev->prot_length;
432 
433 	if (!prot_fd) {
434 		pr_err("Unable to locate fd_dev->fd_prot_file\n");
435 		return -ENODEV;
436 	}
437 
438 	prot_length = nolb * se_dev->prot_length;
439 
440 	for (prot = 0; prot < prot_length;) {
441 		sector_t len = min_t(sector_t, bufsize, prot_length - prot);
442 		ssize_t ret = kernel_write(prot_fd, buf, len, pos + prot);
443 
444 		if (ret != len) {
445 			pr_err("vfs_write to prot file failed: %zd\n", ret);
446 			return ret < 0 ? ret : -ENODEV;
447 		}
448 		prot += ret;
449 	}
450 
451 	return 0;
452 }
453 
454 static int
455 fd_do_prot_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
456 {
457 	void *buf;
458 	int rc;
459 
460 	buf = (void *)__get_free_page(GFP_KERNEL);
461 	if (!buf) {
462 		pr_err("Unable to allocate FILEIO prot buf\n");
463 		return -ENOMEM;
464 	}
465 	memset(buf, 0xff, PAGE_SIZE);
466 
467 	rc = fd_do_prot_fill(cmd->se_dev, lba, nolb, buf, PAGE_SIZE);
468 
469 	free_page((unsigned long)buf);
470 
471 	return rc;
472 }
473 
474 static sense_reason_t
475 fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
476 {
477 	struct file *file = FD_DEV(cmd->se_dev)->fd_file;
478 	struct inode *inode = file->f_mapping->host;
479 	int ret;
480 
481 	if (cmd->se_dev->dev_attrib.pi_prot_type) {
482 		ret = fd_do_prot_unmap(cmd, lba, nolb);
483 		if (ret)
484 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
485 	}
486 
487 	if (S_ISBLK(inode->i_mode)) {
488 		/* The backend is block device, use discard */
489 		struct block_device *bdev = inode->i_bdev;
490 		struct se_device *dev = cmd->se_dev;
491 
492 		ret = blkdev_issue_discard(bdev,
493 					   target_to_linux_sector(dev, lba),
494 					   target_to_linux_sector(dev,  nolb),
495 					   GFP_KERNEL, 0);
496 		if (ret < 0) {
497 			pr_warn("FILEIO: blkdev_issue_discard() failed: %d\n",
498 				ret);
499 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
500 		}
501 	} else {
502 		/* The backend is normal file, use fallocate */
503 		struct se_device *se_dev = cmd->se_dev;
504 		loff_t pos = lba * se_dev->dev_attrib.block_size;
505 		unsigned int len = nolb * se_dev->dev_attrib.block_size;
506 		int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
507 
508 		if (!file->f_op->fallocate)
509 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
510 
511 		ret = file->f_op->fallocate(file, mode, pos, len);
512 		if (ret < 0) {
513 			pr_warn("FILEIO: fallocate() failed: %d\n", ret);
514 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
515 		}
516 	}
517 
518 	return 0;
519 }
520 
521 static sense_reason_t
522 fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
523 	      enum dma_data_direction data_direction)
524 {
525 	struct se_device *dev = cmd->se_dev;
526 	struct fd_dev *fd_dev = FD_DEV(dev);
527 	struct file *file = fd_dev->fd_file;
528 	struct file *pfile = fd_dev->fd_prot_file;
529 	sense_reason_t rc;
530 	int ret = 0;
531 	/*
532 	 * We are currently limited by the number of iovecs (2048) per
533 	 * single vfs_[writev,readv] call.
534 	 */
535 	if (cmd->data_length > FD_MAX_BYTES) {
536 		pr_err("FILEIO: Not able to process I/O of %u bytes due to"
537 		       "FD_MAX_BYTES: %u iovec count limitation\n",
538 			cmd->data_length, FD_MAX_BYTES);
539 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
540 	}
541 	/*
542 	 * Call vectorized fileio functions to map struct scatterlist
543 	 * physical memory addresses to struct iovec virtual memory.
544 	 */
545 	if (data_direction == DMA_FROM_DEVICE) {
546 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
547 			ret = fd_do_rw(cmd, pfile, dev->prot_length,
548 				       cmd->t_prot_sg, cmd->t_prot_nents,
549 				       cmd->prot_length, 0);
550 			if (ret < 0)
551 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
552 		}
553 
554 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
555 			       sgl, sgl_nents, cmd->data_length, 0);
556 
557 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type &&
558 		    dev->dev_attrib.pi_prot_verify) {
559 			u32 sectors = cmd->data_length >>
560 					ilog2(dev->dev_attrib.block_size);
561 
562 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
563 					    0, cmd->t_prot_sg, 0);
564 			if (rc)
565 				return rc;
566 		}
567 	} else {
568 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type &&
569 		    dev->dev_attrib.pi_prot_verify) {
570 			u32 sectors = cmd->data_length >>
571 					ilog2(dev->dev_attrib.block_size);
572 
573 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
574 					    0, cmd->t_prot_sg, 0);
575 			if (rc)
576 				return rc;
577 		}
578 
579 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
580 			       sgl, sgl_nents, cmd->data_length, 1);
581 		/*
582 		 * Perform implicit vfs_fsync_range() for fd_do_writev() ops
583 		 * for SCSI WRITEs with Forced Unit Access (FUA) set.
584 		 * Allow this to happen independent of WCE=0 setting.
585 		 */
586 		if (ret > 0 && (cmd->se_cmd_flags & SCF_FUA)) {
587 			loff_t start = cmd->t_task_lba *
588 				dev->dev_attrib.block_size;
589 			loff_t end;
590 
591 			if (cmd->data_length)
592 				end = start + cmd->data_length - 1;
593 			else
594 				end = LLONG_MAX;
595 
596 			vfs_fsync_range(fd_dev->fd_file, start, end, 1);
597 		}
598 
599 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {
600 			ret = fd_do_rw(cmd, pfile, dev->prot_length,
601 				       cmd->t_prot_sg, cmd->t_prot_nents,
602 				       cmd->prot_length, 1);
603 			if (ret < 0)
604 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
605 		}
606 	}
607 
608 	if (ret < 0)
609 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
610 
611 	target_complete_cmd(cmd, SAM_STAT_GOOD);
612 	return 0;
613 }
614 
615 enum {
616 	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
617 };
618 
619 static match_table_t tokens = {
620 	{Opt_fd_dev_name, "fd_dev_name=%s"},
621 	{Opt_fd_dev_size, "fd_dev_size=%s"},
622 	{Opt_fd_buffered_io, "fd_buffered_io=%d"},
623 	{Opt_err, NULL}
624 };
625 
626 static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
627 		const char *page, ssize_t count)
628 {
629 	struct fd_dev *fd_dev = FD_DEV(dev);
630 	char *orig, *ptr, *arg_p, *opts;
631 	substring_t args[MAX_OPT_ARGS];
632 	int ret = 0, arg, token;
633 
634 	opts = kstrdup(page, GFP_KERNEL);
635 	if (!opts)
636 		return -ENOMEM;
637 
638 	orig = opts;
639 
640 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
641 		if (!*ptr)
642 			continue;
643 
644 		token = match_token(ptr, tokens, args);
645 		switch (token) {
646 		case Opt_fd_dev_name:
647 			if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
648 				FD_MAX_DEV_NAME) == 0) {
649 				ret = -EINVAL;
650 				break;
651 			}
652 			pr_debug("FILEIO: Referencing Path: %s\n",
653 					fd_dev->fd_dev_name);
654 			fd_dev->fbd_flags |= FBDF_HAS_PATH;
655 			break;
656 		case Opt_fd_dev_size:
657 			arg_p = match_strdup(&args[0]);
658 			if (!arg_p) {
659 				ret = -ENOMEM;
660 				break;
661 			}
662 			ret = kstrtoull(arg_p, 0, &fd_dev->fd_dev_size);
663 			kfree(arg_p);
664 			if (ret < 0) {
665 				pr_err("kstrtoull() failed for"
666 						" fd_dev_size=\n");
667 				goto out;
668 			}
669 			pr_debug("FILEIO: Referencing Size: %llu"
670 					" bytes\n", fd_dev->fd_dev_size);
671 			fd_dev->fbd_flags |= FBDF_HAS_SIZE;
672 			break;
673 		case Opt_fd_buffered_io:
674 			ret = match_int(args, &arg);
675 			if (ret)
676 				goto out;
677 			if (arg != 1) {
678 				pr_err("bogus fd_buffered_io=%d value\n", arg);
679 				ret = -EINVAL;
680 				goto out;
681 			}
682 
683 			pr_debug("FILEIO: Using buffered I/O"
684 				" operations for struct fd_dev\n");
685 
686 			fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
687 			break;
688 		default:
689 			break;
690 		}
691 	}
692 
693 out:
694 	kfree(orig);
695 	return (!ret) ? count : ret;
696 }
697 
698 static ssize_t fd_show_configfs_dev_params(struct se_device *dev, char *b)
699 {
700 	struct fd_dev *fd_dev = FD_DEV(dev);
701 	ssize_t bl = 0;
702 
703 	bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
704 	bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s\n",
705 		fd_dev->fd_dev_name, fd_dev->fd_dev_size,
706 		(fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
707 		"Buffered-WCE" : "O_DSYNC");
708 	return bl;
709 }
710 
711 static sector_t fd_get_blocks(struct se_device *dev)
712 {
713 	struct fd_dev *fd_dev = FD_DEV(dev);
714 	struct file *f = fd_dev->fd_file;
715 	struct inode *i = f->f_mapping->host;
716 	unsigned long long dev_size;
717 	/*
718 	 * When using a file that references an underlying struct block_device,
719 	 * ensure dev_size is always based on the current inode size in order
720 	 * to handle underlying block_device resize operations.
721 	 */
722 	if (S_ISBLK(i->i_mode))
723 		dev_size = i_size_read(i);
724 	else
725 		dev_size = fd_dev->fd_dev_size;
726 
727 	return div_u64(dev_size - dev->dev_attrib.block_size,
728 		       dev->dev_attrib.block_size);
729 }
730 
731 static int fd_init_prot(struct se_device *dev)
732 {
733 	struct fd_dev *fd_dev = FD_DEV(dev);
734 	struct file *prot_file, *file = fd_dev->fd_file;
735 	struct inode *inode;
736 	int ret, flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
737 	char buf[FD_MAX_DEV_PROT_NAME];
738 
739 	if (!file) {
740 		pr_err("Unable to locate fd_dev->fd_file\n");
741 		return -ENODEV;
742 	}
743 
744 	inode = file->f_mapping->host;
745 	if (S_ISBLK(inode->i_mode)) {
746 		pr_err("FILEIO Protection emulation only supported on"
747 		       " !S_ISBLK\n");
748 		return -ENOSYS;
749 	}
750 
751 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE)
752 		flags &= ~O_DSYNC;
753 
754 	snprintf(buf, FD_MAX_DEV_PROT_NAME, "%s.protection",
755 		 fd_dev->fd_dev_name);
756 
757 	prot_file = filp_open(buf, flags, 0600);
758 	if (IS_ERR(prot_file)) {
759 		pr_err("filp_open(%s) failed\n", buf);
760 		ret = PTR_ERR(prot_file);
761 		return ret;
762 	}
763 	fd_dev->fd_prot_file = prot_file;
764 
765 	return 0;
766 }
767 
768 static int fd_format_prot(struct se_device *dev)
769 {
770 	unsigned char *buf;
771 	int unit_size = FDBD_FORMAT_UNIT_SIZE * dev->dev_attrib.block_size;
772 	int ret;
773 
774 	if (!dev->dev_attrib.pi_prot_type) {
775 		pr_err("Unable to format_prot while pi_prot_type == 0\n");
776 		return -ENODEV;
777 	}
778 
779 	buf = vzalloc(unit_size);
780 	if (!buf) {
781 		pr_err("Unable to allocate FILEIO prot buf\n");
782 		return -ENOMEM;
783 	}
784 
785 	pr_debug("Using FILEIO prot_length: %llu\n",
786 		 (unsigned long long)(dev->transport->get_blocks(dev) + 1) *
787 					dev->prot_length);
788 
789 	memset(buf, 0xff, unit_size);
790 	ret = fd_do_prot_fill(dev, 0, dev->transport->get_blocks(dev) + 1,
791 			      buf, unit_size);
792 	vfree(buf);
793 	return ret;
794 }
795 
796 static void fd_free_prot(struct se_device *dev)
797 {
798 	struct fd_dev *fd_dev = FD_DEV(dev);
799 
800 	if (!fd_dev->fd_prot_file)
801 		return;
802 
803 	filp_close(fd_dev->fd_prot_file, NULL);
804 	fd_dev->fd_prot_file = NULL;
805 }
806 
807 static struct sbc_ops fd_sbc_ops = {
808 	.execute_rw		= fd_execute_rw,
809 	.execute_sync_cache	= fd_execute_sync_cache,
810 	.execute_write_same	= fd_execute_write_same,
811 	.execute_unmap		= fd_execute_unmap,
812 };
813 
814 static sense_reason_t
815 fd_parse_cdb(struct se_cmd *cmd)
816 {
817 	return sbc_parse_cdb(cmd, &fd_sbc_ops);
818 }
819 
820 static const struct target_backend_ops fileio_ops = {
821 	.name			= "fileio",
822 	.inquiry_prod		= "FILEIO",
823 	.inquiry_rev		= FD_VERSION,
824 	.owner			= THIS_MODULE,
825 	.attach_hba		= fd_attach_hba,
826 	.detach_hba		= fd_detach_hba,
827 	.alloc_device		= fd_alloc_device,
828 	.configure_device	= fd_configure_device,
829 	.free_device		= fd_free_device,
830 	.parse_cdb		= fd_parse_cdb,
831 	.set_configfs_dev_params = fd_set_configfs_dev_params,
832 	.show_configfs_dev_params = fd_show_configfs_dev_params,
833 	.get_device_type	= sbc_get_device_type,
834 	.get_blocks		= fd_get_blocks,
835 	.init_prot		= fd_init_prot,
836 	.format_prot		= fd_format_prot,
837 	.free_prot		= fd_free_prot,
838 	.tb_dev_attrib_attrs	= sbc_attrib_attrs,
839 };
840 
841 static int __init fileio_module_init(void)
842 {
843 	return transport_backend_register(&fileio_ops);
844 }
845 
846 static void __exit fileio_module_exit(void)
847 {
848 	target_backend_unregister(&fileio_ops);
849 }
850 
851 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
852 MODULE_AUTHOR("nab@Linux-iSCSI.org");
853 MODULE_LICENSE("GPL");
854 
855 module_init(fileio_module_init);
856 module_exit(fileio_module_exit);
857