1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3  * Filename:  target_core_file.c
4  *
5  * This file contains the Storage Engine <-> FILEIO transport specific functions
6  *
7  * (c) Copyright 2005-2013 Datera, Inc.
8  *
9  * Nicholas A. Bellinger <nab@kernel.org>
10  *
11  ******************************************************************************/
12 
13 #include <linux/string.h>
14 #include <linux/parser.h>
15 #include <linux/timer.h>
16 #include <linux/blkdev.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19 #include <linux/module.h>
20 #include <linux/vmalloc.h>
21 #include <linux/falloc.h>
22 #include <linux/uio.h>
23 #include <linux/scatterlist.h>
24 #include <scsi/scsi_proto.h>
25 #include <asm/unaligned.h>
26 
27 #include <target/target_core_base.h>
28 #include <target/target_core_backend.h>
29 
30 #include "target_core_file.h"
31 
32 static inline struct fd_dev *FD_DEV(struct se_device *dev)
33 {
34 	return container_of(dev, struct fd_dev, dev);
35 }
36 
37 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
38 {
39 	struct fd_host *fd_host;
40 
41 	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
42 	if (!fd_host) {
43 		pr_err("Unable to allocate memory for struct fd_host\n");
44 		return -ENOMEM;
45 	}
46 
47 	fd_host->fd_host_id = host_id;
48 
49 	hba->hba_ptr = fd_host;
50 
51 	pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
52 		" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
53 		TARGET_CORE_VERSION);
54 	pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic\n",
55 		hba->hba_id, fd_host->fd_host_id);
56 
57 	return 0;
58 }
59 
60 static void fd_detach_hba(struct se_hba *hba)
61 {
62 	struct fd_host *fd_host = hba->hba_ptr;
63 
64 	pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
65 		" Target Core\n", hba->hba_id, fd_host->fd_host_id);
66 
67 	kfree(fd_host);
68 	hba->hba_ptr = NULL;
69 }
70 
71 static struct se_device *fd_alloc_device(struct se_hba *hba, const char *name)
72 {
73 	struct fd_dev *fd_dev;
74 	struct fd_host *fd_host = hba->hba_ptr;
75 
76 	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
77 	if (!fd_dev) {
78 		pr_err("Unable to allocate memory for struct fd_dev\n");
79 		return NULL;
80 	}
81 
82 	fd_dev->fd_host = fd_host;
83 
84 	pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
85 
86 	return &fd_dev->dev;
87 }
88 
89 static bool fd_configure_unmap(struct se_device *dev)
90 {
91 	struct file *file = FD_DEV(dev)->fd_file;
92 	struct inode *inode = file->f_mapping->host;
93 
94 	if (S_ISBLK(inode->i_mode))
95 		return target_configure_unmap_from_queue(&dev->dev_attrib,
96 							 I_BDEV(inode));
97 
98 	/* Limit UNMAP emulation to 8k Number of LBAs (NoLB) */
99 	dev->dev_attrib.max_unmap_lba_count = 0x2000;
100 	/* Currently hardcoded to 1 in Linux/SCSI code. */
101 	dev->dev_attrib.max_unmap_block_desc_count = 1;
102 	dev->dev_attrib.unmap_granularity = 1;
103 	dev->dev_attrib.unmap_granularity_alignment = 0;
104 	return true;
105 }
106 
107 static int fd_configure_device(struct se_device *dev)
108 {
109 	struct fd_dev *fd_dev = FD_DEV(dev);
110 	struct fd_host *fd_host = dev->se_hba->hba_ptr;
111 	struct file *file;
112 	struct inode *inode = NULL;
113 	int flags, ret = -EINVAL;
114 
115 	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
116 		pr_err("Missing fd_dev_name=\n");
117 		return -EINVAL;
118 	}
119 
120 	/*
121 	 * Use O_DSYNC by default instead of O_SYNC to forgo syncing
122 	 * of pure timestamp updates.
123 	 */
124 	flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
125 
126 	/*
127 	 * Optionally allow fd_buffered_io=1 to be enabled for people
128 	 * who want use the fs buffer cache as an WriteCache mechanism.
129 	 *
130 	 * This means that in event of a hard failure, there is a risk
131 	 * of silent data-loss if the SCSI client has *not* performed a
132 	 * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
133 	 * to write-out the entire device cache.
134 	 */
135 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
136 		pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
137 		flags &= ~O_DSYNC;
138 	}
139 
140 	file = filp_open(fd_dev->fd_dev_name, flags, 0600);
141 	if (IS_ERR(file)) {
142 		pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
143 		ret = PTR_ERR(file);
144 		goto fail;
145 	}
146 	fd_dev->fd_file = file;
147 	/*
148 	 * If using a block backend with this struct file, we extract
149 	 * fd_dev->fd_[block,dev]_size from struct block_device.
150 	 *
151 	 * Otherwise, we use the passed fd_size= from configfs
152 	 */
153 	inode = file->f_mapping->host;
154 	if (S_ISBLK(inode->i_mode)) {
155 		struct block_device *bdev = I_BDEV(inode);
156 		unsigned long long dev_size;
157 
158 		fd_dev->fd_block_size = bdev_logical_block_size(bdev);
159 		/*
160 		 * Determine the number of bytes from i_size_read() minus
161 		 * one (1) logical sector from underlying struct block_device
162 		 */
163 		dev_size = (i_size_read(file->f_mapping->host) -
164 				       fd_dev->fd_block_size);
165 
166 		pr_debug("FILEIO: Using size: %llu bytes from struct"
167 			" block_device blocks: %llu logical_block_size: %d\n",
168 			dev_size, div_u64(dev_size, fd_dev->fd_block_size),
169 			fd_dev->fd_block_size);
170 		/*
171 		 * Enable write same emulation for IBLOCK and use 0xFFFF as
172 		 * the smaller WRITE_SAME(10) only has a two-byte block count.
173 		 */
174 		dev->dev_attrib.max_write_same_len = 0xFFFF;
175 
176 		if (bdev_nonrot(bdev))
177 			dev->dev_attrib.is_nonrot = 1;
178 	} else {
179 		if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
180 			pr_err("FILEIO: Missing fd_dev_size="
181 				" parameter, and no backing struct"
182 				" block_device\n");
183 			goto fail;
184 		}
185 
186 		fd_dev->fd_block_size = FD_BLOCKSIZE;
187 
188 		/*
189 		 * Limit WRITE_SAME w/ UNMAP=0 emulation to 8k Number of LBAs (NoLB)
190 		 * based upon struct iovec limit for vfs_writev()
191 		 */
192 		dev->dev_attrib.max_write_same_len = 0x1000;
193 	}
194 
195 	dev->dev_attrib.hw_block_size = fd_dev->fd_block_size;
196 	dev->dev_attrib.max_bytes_per_io = FD_MAX_BYTES;
197 	dev->dev_attrib.hw_max_sectors = FD_MAX_BYTES / fd_dev->fd_block_size;
198 	dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
199 
200 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
201 		pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
202 			" with FDBD_HAS_BUFFERED_IO_WCE\n");
203 		dev->dev_attrib.emulate_write_cache = 1;
204 	}
205 
206 	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
207 	fd_dev->fd_queue_depth = dev->queue_depth;
208 
209 	pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
210 		" %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
211 			fd_dev->fd_dev_name, fd_dev->fd_dev_size);
212 
213 	return 0;
214 fail:
215 	if (fd_dev->fd_file) {
216 		filp_close(fd_dev->fd_file, NULL);
217 		fd_dev->fd_file = NULL;
218 	}
219 	return ret;
220 }
221 
222 static void fd_dev_call_rcu(struct rcu_head *p)
223 {
224 	struct se_device *dev = container_of(p, struct se_device, rcu_head);
225 	struct fd_dev *fd_dev = FD_DEV(dev);
226 
227 	kfree(fd_dev);
228 }
229 
230 static void fd_free_device(struct se_device *dev)
231 {
232 	call_rcu(&dev->rcu_head, fd_dev_call_rcu);
233 }
234 
235 static void fd_destroy_device(struct se_device *dev)
236 {
237 	struct fd_dev *fd_dev = FD_DEV(dev);
238 
239 	if (fd_dev->fd_file) {
240 		filp_close(fd_dev->fd_file, NULL);
241 		fd_dev->fd_file = NULL;
242 	}
243 }
244 
245 struct target_core_file_cmd {
246 	unsigned long	len;
247 	struct se_cmd	*cmd;
248 	struct kiocb	iocb;
249 	struct bio_vec	bvecs[];
250 };
251 
252 static void cmd_rw_aio_complete(struct kiocb *iocb, long ret)
253 {
254 	struct target_core_file_cmd *cmd;
255 
256 	cmd = container_of(iocb, struct target_core_file_cmd, iocb);
257 
258 	if (ret != cmd->len)
259 		target_complete_cmd(cmd->cmd, SAM_STAT_CHECK_CONDITION);
260 	else
261 		target_complete_cmd(cmd->cmd, SAM_STAT_GOOD);
262 
263 	kfree(cmd);
264 }
265 
266 static sense_reason_t
267 fd_execute_rw_aio(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
268 	      enum dma_data_direction data_direction)
269 {
270 	int is_write = !(data_direction == DMA_FROM_DEVICE);
271 	struct se_device *dev = cmd->se_dev;
272 	struct fd_dev *fd_dev = FD_DEV(dev);
273 	struct file *file = fd_dev->fd_file;
274 	struct target_core_file_cmd *aio_cmd;
275 	struct iov_iter iter;
276 	struct scatterlist *sg;
277 	ssize_t len = 0;
278 	int ret = 0, i;
279 
280 	aio_cmd = kmalloc(struct_size(aio_cmd, bvecs, sgl_nents), GFP_KERNEL);
281 	if (!aio_cmd)
282 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
283 
284 	for_each_sg(sgl, sg, sgl_nents, i) {
285 		aio_cmd->bvecs[i].bv_page = sg_page(sg);
286 		aio_cmd->bvecs[i].bv_len = sg->length;
287 		aio_cmd->bvecs[i].bv_offset = sg->offset;
288 
289 		len += sg->length;
290 	}
291 
292 	iov_iter_bvec(&iter, is_write, aio_cmd->bvecs, sgl_nents, len);
293 
294 	aio_cmd->cmd = cmd;
295 	aio_cmd->len = len;
296 	aio_cmd->iocb.ki_pos = cmd->t_task_lba * dev->dev_attrib.block_size;
297 	aio_cmd->iocb.ki_filp = file;
298 	aio_cmd->iocb.ki_complete = cmd_rw_aio_complete;
299 	aio_cmd->iocb.ki_flags = IOCB_DIRECT;
300 
301 	if (is_write && (cmd->se_cmd_flags & SCF_FUA))
302 		aio_cmd->iocb.ki_flags |= IOCB_DSYNC;
303 
304 	if (is_write)
305 		ret = call_write_iter(file, &aio_cmd->iocb, &iter);
306 	else
307 		ret = call_read_iter(file, &aio_cmd->iocb, &iter);
308 
309 	if (ret != -EIOCBQUEUED)
310 		cmd_rw_aio_complete(&aio_cmd->iocb, ret);
311 
312 	return 0;
313 }
314 
315 static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
316 		    u32 block_size, struct scatterlist *sgl,
317 		    u32 sgl_nents, u32 data_length, int is_write)
318 {
319 	struct scatterlist *sg;
320 	struct iov_iter iter;
321 	struct bio_vec *bvec;
322 	ssize_t len = 0;
323 	loff_t pos = (cmd->t_task_lba * block_size);
324 	int ret = 0, i;
325 
326 	bvec = kcalloc(sgl_nents, sizeof(struct bio_vec), GFP_KERNEL);
327 	if (!bvec) {
328 		pr_err("Unable to allocate fd_do_readv iov[]\n");
329 		return -ENOMEM;
330 	}
331 
332 	for_each_sg(sgl, sg, sgl_nents, i) {
333 		bvec[i].bv_page = sg_page(sg);
334 		bvec[i].bv_len = sg->length;
335 		bvec[i].bv_offset = sg->offset;
336 
337 		len += sg->length;
338 	}
339 
340 	iov_iter_bvec(&iter, READ, bvec, sgl_nents, len);
341 	if (is_write)
342 		ret = vfs_iter_write(fd, &iter, &pos, 0);
343 	else
344 		ret = vfs_iter_read(fd, &iter, &pos, 0);
345 
346 	if (is_write) {
347 		if (ret < 0 || ret != data_length) {
348 			pr_err("%s() write returned %d\n", __func__, ret);
349 			if (ret >= 0)
350 				ret = -EINVAL;
351 		}
352 	} else {
353 		/*
354 		 * Return zeros and GOOD status even if the READ did not return
355 		 * the expected virt_size for struct file w/o a backing struct
356 		 * block_device.
357 		 */
358 		if (S_ISBLK(file_inode(fd)->i_mode)) {
359 			if (ret < 0 || ret != data_length) {
360 				pr_err("%s() returned %d, expecting %u for "
361 						"S_ISBLK\n", __func__, ret,
362 						data_length);
363 				if (ret >= 0)
364 					ret = -EINVAL;
365 			}
366 		} else {
367 			if (ret < 0) {
368 				pr_err("%s() returned %d for non S_ISBLK\n",
369 						__func__, ret);
370 			} else if (ret != data_length) {
371 				/*
372 				 * Short read case:
373 				 * Probably some one truncate file under us.
374 				 * We must explicitly zero sg-pages to prevent
375 				 * expose uninizialized pages to userspace.
376 				 */
377 				if (ret < data_length)
378 					ret += iov_iter_zero(data_length - ret, &iter);
379 				else
380 					ret = -EINVAL;
381 			}
382 		}
383 	}
384 	kfree(bvec);
385 	return ret;
386 }
387 
388 static sense_reason_t
389 fd_execute_sync_cache(struct se_cmd *cmd)
390 {
391 	struct se_device *dev = cmd->se_dev;
392 	struct fd_dev *fd_dev = FD_DEV(dev);
393 	int immed = (cmd->t_task_cdb[1] & 0x2);
394 	loff_t start, end;
395 	int ret;
396 
397 	/*
398 	 * If the Immediate bit is set, queue up the GOOD response
399 	 * for this SYNCHRONIZE_CACHE op
400 	 */
401 	if (immed)
402 		target_complete_cmd(cmd, SAM_STAT_GOOD);
403 
404 	/*
405 	 * Determine if we will be flushing the entire device.
406 	 */
407 	if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
408 		start = 0;
409 		end = LLONG_MAX;
410 	} else {
411 		start = cmd->t_task_lba * dev->dev_attrib.block_size;
412 		if (cmd->data_length)
413 			end = start + cmd->data_length - 1;
414 		else
415 			end = LLONG_MAX;
416 	}
417 
418 	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
419 	if (ret != 0)
420 		pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
421 
422 	if (immed)
423 		return 0;
424 
425 	if (ret)
426 		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
427 	else
428 		target_complete_cmd(cmd, SAM_STAT_GOOD);
429 
430 	return 0;
431 }
432 
433 static sense_reason_t
434 fd_execute_write_same(struct se_cmd *cmd)
435 {
436 	struct se_device *se_dev = cmd->se_dev;
437 	struct fd_dev *fd_dev = FD_DEV(se_dev);
438 	loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;
439 	sector_t nolb = sbc_get_write_same_sectors(cmd);
440 	struct iov_iter iter;
441 	struct bio_vec *bvec;
442 	unsigned int len = 0, i;
443 	ssize_t ret;
444 
445 	if (cmd->prot_op) {
446 		pr_err("WRITE_SAME: Protection information with FILEIO"
447 		       " backends not supported\n");
448 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
449 	}
450 
451 	if (!cmd->t_data_nents)
452 		return TCM_INVALID_CDB_FIELD;
453 
454 	if (cmd->t_data_nents > 1 ||
455 	    cmd->t_data_sg[0].length != cmd->se_dev->dev_attrib.block_size) {
456 		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
457 			" block_size: %u\n",
458 			cmd->t_data_nents,
459 			cmd->t_data_sg[0].length,
460 			cmd->se_dev->dev_attrib.block_size);
461 		return TCM_INVALID_CDB_FIELD;
462 	}
463 
464 	bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
465 	if (!bvec)
466 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
467 
468 	for (i = 0; i < nolb; i++) {
469 		bvec[i].bv_page = sg_page(&cmd->t_data_sg[0]);
470 		bvec[i].bv_len = cmd->t_data_sg[0].length;
471 		bvec[i].bv_offset = cmd->t_data_sg[0].offset;
472 
473 		len += se_dev->dev_attrib.block_size;
474 	}
475 
476 	iov_iter_bvec(&iter, READ, bvec, nolb, len);
477 	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos, 0);
478 
479 	kfree(bvec);
480 	if (ret < 0 || ret != len) {
481 		pr_err("vfs_iter_write() returned %zd for write same\n", ret);
482 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
483 	}
484 
485 	target_complete_cmd(cmd, SAM_STAT_GOOD);
486 	return 0;
487 }
488 
489 static int
490 fd_do_prot_fill(struct se_device *se_dev, sector_t lba, sector_t nolb,
491 		void *buf, size_t bufsize)
492 {
493 	struct fd_dev *fd_dev = FD_DEV(se_dev);
494 	struct file *prot_fd = fd_dev->fd_prot_file;
495 	sector_t prot_length, prot;
496 	loff_t pos = lba * se_dev->prot_length;
497 
498 	if (!prot_fd) {
499 		pr_err("Unable to locate fd_dev->fd_prot_file\n");
500 		return -ENODEV;
501 	}
502 
503 	prot_length = nolb * se_dev->prot_length;
504 
505 	memset(buf, 0xff, bufsize);
506 	for (prot = 0; prot < prot_length;) {
507 		sector_t len = min_t(sector_t, bufsize, prot_length - prot);
508 		ssize_t ret = kernel_write(prot_fd, buf, len, &pos);
509 
510 		if (ret != len) {
511 			pr_err("vfs_write to prot file failed: %zd\n", ret);
512 			return ret < 0 ? ret : -ENODEV;
513 		}
514 		prot += ret;
515 	}
516 
517 	return 0;
518 }
519 
520 static int
521 fd_do_prot_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
522 {
523 	void *buf;
524 	int rc;
525 
526 	buf = (void *)__get_free_page(GFP_KERNEL);
527 	if (!buf) {
528 		pr_err("Unable to allocate FILEIO prot buf\n");
529 		return -ENOMEM;
530 	}
531 
532 	rc = fd_do_prot_fill(cmd->se_dev, lba, nolb, buf, PAGE_SIZE);
533 
534 	free_page((unsigned long)buf);
535 
536 	return rc;
537 }
538 
539 static sense_reason_t
540 fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
541 {
542 	struct file *file = FD_DEV(cmd->se_dev)->fd_file;
543 	struct inode *inode = file->f_mapping->host;
544 	int ret;
545 
546 	if (!nolb) {
547 		return 0;
548 	}
549 
550 	if (cmd->se_dev->dev_attrib.pi_prot_type) {
551 		ret = fd_do_prot_unmap(cmd, lba, nolb);
552 		if (ret)
553 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
554 	}
555 
556 	if (S_ISBLK(inode->i_mode)) {
557 		/* The backend is block device, use discard */
558 		struct block_device *bdev = I_BDEV(inode);
559 		struct se_device *dev = cmd->se_dev;
560 
561 		ret = blkdev_issue_discard(bdev,
562 					   target_to_linux_sector(dev, lba),
563 					   target_to_linux_sector(dev,  nolb),
564 					   GFP_KERNEL);
565 		if (ret < 0) {
566 			pr_warn("FILEIO: blkdev_issue_discard() failed: %d\n",
567 				ret);
568 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
569 		}
570 	} else {
571 		/* The backend is normal file, use fallocate */
572 		struct se_device *se_dev = cmd->se_dev;
573 		loff_t pos = lba * se_dev->dev_attrib.block_size;
574 		unsigned int len = nolb * se_dev->dev_attrib.block_size;
575 		int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
576 
577 		if (!file->f_op->fallocate)
578 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
579 
580 		ret = file->f_op->fallocate(file, mode, pos, len);
581 		if (ret < 0) {
582 			pr_warn("FILEIO: fallocate() failed: %d\n", ret);
583 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
584 		}
585 	}
586 
587 	return 0;
588 }
589 
590 static sense_reason_t
591 fd_execute_rw_buffered(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
592 	      enum dma_data_direction data_direction)
593 {
594 	struct se_device *dev = cmd->se_dev;
595 	struct fd_dev *fd_dev = FD_DEV(dev);
596 	struct file *file = fd_dev->fd_file;
597 	struct file *pfile = fd_dev->fd_prot_file;
598 	sense_reason_t rc;
599 	int ret = 0;
600 	/*
601 	 * Call vectorized fileio functions to map struct scatterlist
602 	 * physical memory addresses to struct iovec virtual memory.
603 	 */
604 	if (data_direction == DMA_FROM_DEVICE) {
605 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
606 			ret = fd_do_rw(cmd, pfile, dev->prot_length,
607 				       cmd->t_prot_sg, cmd->t_prot_nents,
608 				       cmd->prot_length, 0);
609 			if (ret < 0)
610 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
611 		}
612 
613 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
614 			       sgl, sgl_nents, cmd->data_length, 0);
615 
616 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type &&
617 		    dev->dev_attrib.pi_prot_verify) {
618 			u32 sectors = cmd->data_length >>
619 					ilog2(dev->dev_attrib.block_size);
620 
621 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
622 					    0, cmd->t_prot_sg, 0);
623 			if (rc)
624 				return rc;
625 		}
626 	} else {
627 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type &&
628 		    dev->dev_attrib.pi_prot_verify) {
629 			u32 sectors = cmd->data_length >>
630 					ilog2(dev->dev_attrib.block_size);
631 
632 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
633 					    0, cmd->t_prot_sg, 0);
634 			if (rc)
635 				return rc;
636 		}
637 
638 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
639 			       sgl, sgl_nents, cmd->data_length, 1);
640 		/*
641 		 * Perform implicit vfs_fsync_range() for fd_do_writev() ops
642 		 * for SCSI WRITEs with Forced Unit Access (FUA) set.
643 		 * Allow this to happen independent of WCE=0 setting.
644 		 */
645 		if (ret > 0 && (cmd->se_cmd_flags & SCF_FUA)) {
646 			loff_t start = cmd->t_task_lba *
647 				dev->dev_attrib.block_size;
648 			loff_t end;
649 
650 			if (cmd->data_length)
651 				end = start + cmd->data_length - 1;
652 			else
653 				end = LLONG_MAX;
654 
655 			vfs_fsync_range(fd_dev->fd_file, start, end, 1);
656 		}
657 
658 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {
659 			ret = fd_do_rw(cmd, pfile, dev->prot_length,
660 				       cmd->t_prot_sg, cmd->t_prot_nents,
661 				       cmd->prot_length, 1);
662 			if (ret < 0)
663 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
664 		}
665 	}
666 
667 	if (ret < 0)
668 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
669 
670 	target_complete_cmd(cmd, SAM_STAT_GOOD);
671 	return 0;
672 }
673 
674 static sense_reason_t
675 fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
676 	      enum dma_data_direction data_direction)
677 {
678 	struct se_device *dev = cmd->se_dev;
679 	struct fd_dev *fd_dev = FD_DEV(dev);
680 
681 	/*
682 	 * We are currently limited by the number of iovecs (2048) per
683 	 * single vfs_[writev,readv] call.
684 	 */
685 	if (cmd->data_length > FD_MAX_BYTES) {
686 		pr_err("FILEIO: Not able to process I/O of %u bytes due to"
687 		       "FD_MAX_BYTES: %u iovec count limitation\n",
688 			cmd->data_length, FD_MAX_BYTES);
689 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
690 	}
691 
692 	if (fd_dev->fbd_flags & FDBD_HAS_ASYNC_IO)
693 		return fd_execute_rw_aio(cmd, sgl, sgl_nents, data_direction);
694 	return fd_execute_rw_buffered(cmd, sgl, sgl_nents, data_direction);
695 }
696 
697 enum {
698 	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io,
699 	Opt_fd_async_io, Opt_err
700 };
701 
702 static match_table_t tokens = {
703 	{Opt_fd_dev_name, "fd_dev_name=%s"},
704 	{Opt_fd_dev_size, "fd_dev_size=%s"},
705 	{Opt_fd_buffered_io, "fd_buffered_io=%d"},
706 	{Opt_fd_async_io, "fd_async_io=%d"},
707 	{Opt_err, NULL}
708 };
709 
710 static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
711 		const char *page, ssize_t count)
712 {
713 	struct fd_dev *fd_dev = FD_DEV(dev);
714 	char *orig, *ptr, *arg_p, *opts;
715 	substring_t args[MAX_OPT_ARGS];
716 	int ret = 0, arg, token;
717 
718 	opts = kstrdup(page, GFP_KERNEL);
719 	if (!opts)
720 		return -ENOMEM;
721 
722 	orig = opts;
723 
724 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
725 		if (!*ptr)
726 			continue;
727 
728 		token = match_token(ptr, tokens, args);
729 		switch (token) {
730 		case Opt_fd_dev_name:
731 			if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
732 				FD_MAX_DEV_NAME) == 0) {
733 				ret = -EINVAL;
734 				break;
735 			}
736 			pr_debug("FILEIO: Referencing Path: %s\n",
737 					fd_dev->fd_dev_name);
738 			fd_dev->fbd_flags |= FBDF_HAS_PATH;
739 			break;
740 		case Opt_fd_dev_size:
741 			arg_p = match_strdup(&args[0]);
742 			if (!arg_p) {
743 				ret = -ENOMEM;
744 				break;
745 			}
746 			ret = kstrtoull(arg_p, 0, &fd_dev->fd_dev_size);
747 			kfree(arg_p);
748 			if (ret < 0) {
749 				pr_err("kstrtoull() failed for"
750 						" fd_dev_size=\n");
751 				goto out;
752 			}
753 			pr_debug("FILEIO: Referencing Size: %llu"
754 					" bytes\n", fd_dev->fd_dev_size);
755 			fd_dev->fbd_flags |= FBDF_HAS_SIZE;
756 			break;
757 		case Opt_fd_buffered_io:
758 			ret = match_int(args, &arg);
759 			if (ret)
760 				goto out;
761 			if (arg != 1) {
762 				pr_err("bogus fd_buffered_io=%d value\n", arg);
763 				ret = -EINVAL;
764 				goto out;
765 			}
766 
767 			pr_debug("FILEIO: Using buffered I/O"
768 				" operations for struct fd_dev\n");
769 
770 			fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
771 			break;
772 		case Opt_fd_async_io:
773 			ret = match_int(args, &arg);
774 			if (ret)
775 				goto out;
776 			if (arg != 1) {
777 				pr_err("bogus fd_async_io=%d value\n", arg);
778 				ret = -EINVAL;
779 				goto out;
780 			}
781 
782 			pr_debug("FILEIO: Using async I/O"
783 				" operations for struct fd_dev\n");
784 
785 			fd_dev->fbd_flags |= FDBD_HAS_ASYNC_IO;
786 			break;
787 		default:
788 			break;
789 		}
790 	}
791 
792 out:
793 	kfree(orig);
794 	return (!ret) ? count : ret;
795 }
796 
797 static ssize_t fd_show_configfs_dev_params(struct se_device *dev, char *b)
798 {
799 	struct fd_dev *fd_dev = FD_DEV(dev);
800 	ssize_t bl = 0;
801 
802 	bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
803 	bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s Async: %d\n",
804 		fd_dev->fd_dev_name, fd_dev->fd_dev_size,
805 		(fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
806 		"Buffered-WCE" : "O_DSYNC",
807 		!!(fd_dev->fbd_flags & FDBD_HAS_ASYNC_IO));
808 	return bl;
809 }
810 
811 static sector_t fd_get_blocks(struct se_device *dev)
812 {
813 	struct fd_dev *fd_dev = FD_DEV(dev);
814 	struct file *f = fd_dev->fd_file;
815 	struct inode *i = f->f_mapping->host;
816 	unsigned long long dev_size;
817 	/*
818 	 * When using a file that references an underlying struct block_device,
819 	 * ensure dev_size is always based on the current inode size in order
820 	 * to handle underlying block_device resize operations.
821 	 */
822 	if (S_ISBLK(i->i_mode))
823 		dev_size = i_size_read(i);
824 	else
825 		dev_size = fd_dev->fd_dev_size;
826 
827 	return div_u64(dev_size - dev->dev_attrib.block_size,
828 		       dev->dev_attrib.block_size);
829 }
830 
831 static int fd_init_prot(struct se_device *dev)
832 {
833 	struct fd_dev *fd_dev = FD_DEV(dev);
834 	struct file *prot_file, *file = fd_dev->fd_file;
835 	struct inode *inode;
836 	int ret, flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
837 	char buf[FD_MAX_DEV_PROT_NAME];
838 
839 	if (!file) {
840 		pr_err("Unable to locate fd_dev->fd_file\n");
841 		return -ENODEV;
842 	}
843 
844 	inode = file->f_mapping->host;
845 	if (S_ISBLK(inode->i_mode)) {
846 		pr_err("FILEIO Protection emulation only supported on"
847 		       " !S_ISBLK\n");
848 		return -ENOSYS;
849 	}
850 
851 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE)
852 		flags &= ~O_DSYNC;
853 
854 	snprintf(buf, FD_MAX_DEV_PROT_NAME, "%s.protection",
855 		 fd_dev->fd_dev_name);
856 
857 	prot_file = filp_open(buf, flags, 0600);
858 	if (IS_ERR(prot_file)) {
859 		pr_err("filp_open(%s) failed\n", buf);
860 		ret = PTR_ERR(prot_file);
861 		return ret;
862 	}
863 	fd_dev->fd_prot_file = prot_file;
864 
865 	return 0;
866 }
867 
868 static int fd_format_prot(struct se_device *dev)
869 {
870 	unsigned char *buf;
871 	int unit_size = FDBD_FORMAT_UNIT_SIZE * dev->dev_attrib.block_size;
872 	int ret;
873 
874 	if (!dev->dev_attrib.pi_prot_type) {
875 		pr_err("Unable to format_prot while pi_prot_type == 0\n");
876 		return -ENODEV;
877 	}
878 
879 	buf = vzalloc(unit_size);
880 	if (!buf) {
881 		pr_err("Unable to allocate FILEIO prot buf\n");
882 		return -ENOMEM;
883 	}
884 
885 	pr_debug("Using FILEIO prot_length: %llu\n",
886 		 (unsigned long long)(dev->transport->get_blocks(dev) + 1) *
887 					dev->prot_length);
888 
889 	ret = fd_do_prot_fill(dev, 0, dev->transport->get_blocks(dev) + 1,
890 			      buf, unit_size);
891 	vfree(buf);
892 	return ret;
893 }
894 
895 static void fd_free_prot(struct se_device *dev)
896 {
897 	struct fd_dev *fd_dev = FD_DEV(dev);
898 
899 	if (!fd_dev->fd_prot_file)
900 		return;
901 
902 	filp_close(fd_dev->fd_prot_file, NULL);
903 	fd_dev->fd_prot_file = NULL;
904 }
905 
906 static struct sbc_ops fd_sbc_ops = {
907 	.execute_rw		= fd_execute_rw,
908 	.execute_sync_cache	= fd_execute_sync_cache,
909 	.execute_write_same	= fd_execute_write_same,
910 	.execute_unmap		= fd_execute_unmap,
911 };
912 
913 static sense_reason_t
914 fd_parse_cdb(struct se_cmd *cmd)
915 {
916 	return sbc_parse_cdb(cmd, &fd_sbc_ops);
917 }
918 
919 static const struct target_backend_ops fileio_ops = {
920 	.name			= "fileio",
921 	.inquiry_prod		= "FILEIO",
922 	.inquiry_rev		= FD_VERSION,
923 	.owner			= THIS_MODULE,
924 	.attach_hba		= fd_attach_hba,
925 	.detach_hba		= fd_detach_hba,
926 	.alloc_device		= fd_alloc_device,
927 	.configure_device	= fd_configure_device,
928 	.destroy_device		= fd_destroy_device,
929 	.free_device		= fd_free_device,
930 	.configure_unmap	= fd_configure_unmap,
931 	.parse_cdb		= fd_parse_cdb,
932 	.set_configfs_dev_params = fd_set_configfs_dev_params,
933 	.show_configfs_dev_params = fd_show_configfs_dev_params,
934 	.get_device_type	= sbc_get_device_type,
935 	.get_blocks		= fd_get_blocks,
936 	.init_prot		= fd_init_prot,
937 	.format_prot		= fd_format_prot,
938 	.free_prot		= fd_free_prot,
939 	.tb_dev_attrib_attrs	= sbc_attrib_attrs,
940 };
941 
942 static int __init fileio_module_init(void)
943 {
944 	return transport_backend_register(&fileio_ops);
945 }
946 
947 static void __exit fileio_module_exit(void)
948 {
949 	target_backend_unregister(&fileio_ops);
950 }
951 
952 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
953 MODULE_AUTHOR("nab@Linux-iSCSI.org");
954 MODULE_LICENSE("GPL");
955 
956 module_init(fileio_module_init);
957 module_exit(fileio_module_exit);
958