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 <scsi/scsi_proto.h>
24 #include <asm/unaligned.h>
25 
26 #include <target/target_core_base.h>
27 #include <target/target_core_backend.h>
28 
29 #include "target_core_file.h"
30 
31 static inline struct fd_dev *FD_DEV(struct se_device *dev)
32 {
33 	return container_of(dev, struct fd_dev, dev);
34 }
35 
36 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
37 {
38 	struct fd_host *fd_host;
39 
40 	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
41 	if (!fd_host) {
42 		pr_err("Unable to allocate memory for struct fd_host\n");
43 		return -ENOMEM;
44 	}
45 
46 	fd_host->fd_host_id = host_id;
47 
48 	hba->hba_ptr = fd_host;
49 
50 	pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
51 		" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
52 		TARGET_CORE_VERSION);
53 	pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic\n",
54 		hba->hba_id, fd_host->fd_host_id);
55 
56 	return 0;
57 }
58 
59 static void fd_detach_hba(struct se_hba *hba)
60 {
61 	struct fd_host *fd_host = hba->hba_ptr;
62 
63 	pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
64 		" Target Core\n", hba->hba_id, fd_host->fd_host_id);
65 
66 	kfree(fd_host);
67 	hba->hba_ptr = NULL;
68 }
69 
70 static struct se_device *fd_alloc_device(struct se_hba *hba, const char *name)
71 {
72 	struct fd_dev *fd_dev;
73 	struct fd_host *fd_host = hba->hba_ptr;
74 
75 	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
76 	if (!fd_dev) {
77 		pr_err("Unable to allocate memory for struct fd_dev\n");
78 		return NULL;
79 	}
80 
81 	fd_dev->fd_host = fd_host;
82 
83 	pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
84 
85 	return &fd_dev->dev;
86 }
87 
88 static int fd_configure_device(struct se_device *dev)
89 {
90 	struct fd_dev *fd_dev = FD_DEV(dev);
91 	struct fd_host *fd_host = dev->se_hba->hba_ptr;
92 	struct file *file;
93 	struct inode *inode = NULL;
94 	int flags, ret = -EINVAL;
95 
96 	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
97 		pr_err("Missing fd_dev_name=\n");
98 		return -EINVAL;
99 	}
100 
101 	/*
102 	 * Use O_DSYNC by default instead of O_SYNC to forgo syncing
103 	 * of pure timestamp updates.
104 	 */
105 	flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
106 
107 	/*
108 	 * Optionally allow fd_buffered_io=1 to be enabled for people
109 	 * who want use the fs buffer cache as an WriteCache mechanism.
110 	 *
111 	 * This means that in event of a hard failure, there is a risk
112 	 * of silent data-loss if the SCSI client has *not* performed a
113 	 * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
114 	 * to write-out the entire device cache.
115 	 */
116 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
117 		pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
118 		flags &= ~O_DSYNC;
119 	}
120 
121 	file = filp_open(fd_dev->fd_dev_name, flags, 0600);
122 	if (IS_ERR(file)) {
123 		pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
124 		ret = PTR_ERR(file);
125 		goto fail;
126 	}
127 	fd_dev->fd_file = file;
128 	/*
129 	 * If using a block backend with this struct file, we extract
130 	 * fd_dev->fd_[block,dev]_size from struct block_device.
131 	 *
132 	 * Otherwise, we use the passed fd_size= from configfs
133 	 */
134 	inode = file->f_mapping->host;
135 	if (S_ISBLK(inode->i_mode)) {
136 		struct request_queue *q = bdev_get_queue(I_BDEV(inode));
137 		unsigned long long dev_size;
138 
139 		fd_dev->fd_block_size = bdev_logical_block_size(I_BDEV(inode));
140 		/*
141 		 * Determine the number of bytes from i_size_read() minus
142 		 * one (1) logical sector from underlying struct block_device
143 		 */
144 		dev_size = (i_size_read(file->f_mapping->host) -
145 				       fd_dev->fd_block_size);
146 
147 		pr_debug("FILEIO: Using size: %llu bytes from struct"
148 			" block_device blocks: %llu logical_block_size: %d\n",
149 			dev_size, div_u64(dev_size, fd_dev->fd_block_size),
150 			fd_dev->fd_block_size);
151 
152 		if (target_configure_unmap_from_queue(&dev->dev_attrib, q))
153 			pr_debug("IFILE: BLOCK Discard support available,"
154 				 " disabled by default\n");
155 		/*
156 		 * Enable write same emulation for IBLOCK and use 0xFFFF as
157 		 * the smaller WRITE_SAME(10) only has a two-byte block count.
158 		 */
159 		dev->dev_attrib.max_write_same_len = 0xFFFF;
160 
161 		if (blk_queue_nonrot(q))
162 			dev->dev_attrib.is_nonrot = 1;
163 	} else {
164 		if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
165 			pr_err("FILEIO: Missing fd_dev_size="
166 				" parameter, and no backing struct"
167 				" block_device\n");
168 			goto fail;
169 		}
170 
171 		fd_dev->fd_block_size = FD_BLOCKSIZE;
172 		/*
173 		 * Limit UNMAP emulation to 8k Number of LBAs (NoLB)
174 		 */
175 		dev->dev_attrib.max_unmap_lba_count = 0x2000;
176 		/*
177 		 * Currently hardcoded to 1 in Linux/SCSI code..
178 		 */
179 		dev->dev_attrib.max_unmap_block_desc_count = 1;
180 		dev->dev_attrib.unmap_granularity = 1;
181 		dev->dev_attrib.unmap_granularity_alignment = 0;
182 
183 		/*
184 		 * Limit WRITE_SAME w/ UNMAP=0 emulation to 8k Number of LBAs (NoLB)
185 		 * based upon struct iovec limit for vfs_writev()
186 		 */
187 		dev->dev_attrib.max_write_same_len = 0x1000;
188 	}
189 
190 	dev->dev_attrib.hw_block_size = fd_dev->fd_block_size;
191 	dev->dev_attrib.max_bytes_per_io = FD_MAX_BYTES;
192 	dev->dev_attrib.hw_max_sectors = FD_MAX_BYTES / fd_dev->fd_block_size;
193 	dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
194 
195 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
196 		pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
197 			" with FDBD_HAS_BUFFERED_IO_WCE\n");
198 		dev->dev_attrib.emulate_write_cache = 1;
199 	}
200 
201 	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
202 	fd_dev->fd_queue_depth = dev->queue_depth;
203 
204 	pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
205 		" %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
206 			fd_dev->fd_dev_name, fd_dev->fd_dev_size);
207 
208 	return 0;
209 fail:
210 	if (fd_dev->fd_file) {
211 		filp_close(fd_dev->fd_file, NULL);
212 		fd_dev->fd_file = NULL;
213 	}
214 	return ret;
215 }
216 
217 static void fd_dev_call_rcu(struct rcu_head *p)
218 {
219 	struct se_device *dev = container_of(p, struct se_device, rcu_head);
220 	struct fd_dev *fd_dev = FD_DEV(dev);
221 
222 	kfree(fd_dev);
223 }
224 
225 static void fd_free_device(struct se_device *dev)
226 {
227 	call_rcu(&dev->rcu_head, fd_dev_call_rcu);
228 }
229 
230 static void fd_destroy_device(struct se_device *dev)
231 {
232 	struct fd_dev *fd_dev = FD_DEV(dev);
233 
234 	if (fd_dev->fd_file) {
235 		filp_close(fd_dev->fd_file, NULL);
236 		fd_dev->fd_file = NULL;
237 	}
238 }
239 
240 struct target_core_file_cmd {
241 	unsigned long	len;
242 	struct se_cmd	*cmd;
243 	struct kiocb	iocb;
244 };
245 
246 static void cmd_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
247 {
248 	struct target_core_file_cmd *cmd;
249 
250 	cmd = container_of(iocb, struct target_core_file_cmd, iocb);
251 
252 	if (ret != cmd->len)
253 		target_complete_cmd(cmd->cmd, SAM_STAT_CHECK_CONDITION);
254 	else
255 		target_complete_cmd(cmd->cmd, SAM_STAT_GOOD);
256 
257 	kfree(cmd);
258 }
259 
260 static sense_reason_t
261 fd_execute_rw_aio(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
262 	      enum dma_data_direction data_direction)
263 {
264 	int is_write = !(data_direction == DMA_FROM_DEVICE);
265 	struct se_device *dev = cmd->se_dev;
266 	struct fd_dev *fd_dev = FD_DEV(dev);
267 	struct file *file = fd_dev->fd_file;
268 	struct target_core_file_cmd *aio_cmd;
269 	struct iov_iter iter = {};
270 	struct scatterlist *sg;
271 	struct bio_vec *bvec;
272 	ssize_t len = 0;
273 	int ret = 0, i;
274 
275 	aio_cmd = kmalloc(sizeof(struct target_core_file_cmd), GFP_KERNEL);
276 	if (!aio_cmd)
277 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
278 
279 	bvec = kcalloc(sgl_nents, sizeof(struct bio_vec), GFP_KERNEL);
280 	if (!bvec) {
281 		kfree(aio_cmd);
282 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
283 	}
284 
285 	for_each_sg(sgl, sg, sgl_nents, i) {
286 		bvec[i].bv_page = sg_page(sg);
287 		bvec[i].bv_len = sg->length;
288 		bvec[i].bv_offset = sg->offset;
289 
290 		len += sg->length;
291 	}
292 
293 	iov_iter_bvec(&iter, is_write, bvec, sgl_nents, len);
294 
295 	aio_cmd->cmd = cmd;
296 	aio_cmd->len = len;
297 	aio_cmd->iocb.ki_pos = cmd->t_task_lba * dev->dev_attrib.block_size;
298 	aio_cmd->iocb.ki_filp = file;
299 	aio_cmd->iocb.ki_complete = cmd_rw_aio_complete;
300 	aio_cmd->iocb.ki_flags = IOCB_DIRECT;
301 
302 	if (is_write && (cmd->se_cmd_flags & SCF_FUA))
303 		aio_cmd->iocb.ki_flags |= IOCB_DSYNC;
304 
305 	if (is_write)
306 		ret = call_write_iter(file, &aio_cmd->iocb, &iter);
307 	else
308 		ret = call_read_iter(file, &aio_cmd->iocb, &iter);
309 
310 	kfree(bvec);
311 
312 	if (ret != -EIOCBQUEUED)
313 		cmd_rw_aio_complete(&aio_cmd->iocb, ret, 0);
314 
315 	return 0;
316 }
317 
318 static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
319 		    u32 block_size, struct scatterlist *sgl,
320 		    u32 sgl_nents, u32 data_length, int is_write)
321 {
322 	struct scatterlist *sg;
323 	struct iov_iter iter;
324 	struct bio_vec *bvec;
325 	ssize_t len = 0;
326 	loff_t pos = (cmd->t_task_lba * block_size);
327 	int ret = 0, i;
328 
329 	bvec = kcalloc(sgl_nents, sizeof(struct bio_vec), GFP_KERNEL);
330 	if (!bvec) {
331 		pr_err("Unable to allocate fd_do_readv iov[]\n");
332 		return -ENOMEM;
333 	}
334 
335 	for_each_sg(sgl, sg, sgl_nents, i) {
336 		bvec[i].bv_page = sg_page(sg);
337 		bvec[i].bv_len = sg->length;
338 		bvec[i].bv_offset = sg->offset;
339 
340 		len += sg->length;
341 	}
342 
343 	iov_iter_bvec(&iter, READ, bvec, sgl_nents, len);
344 	if (is_write)
345 		ret = vfs_iter_write(fd, &iter, &pos, 0);
346 	else
347 		ret = vfs_iter_read(fd, &iter, &pos, 0);
348 
349 	if (is_write) {
350 		if (ret < 0 || ret != data_length) {
351 			pr_err("%s() write returned %d\n", __func__, ret);
352 			if (ret >= 0)
353 				ret = -EINVAL;
354 		}
355 	} else {
356 		/*
357 		 * Return zeros and GOOD status even if the READ did not return
358 		 * the expected virt_size for struct file w/o a backing struct
359 		 * block_device.
360 		 */
361 		if (S_ISBLK(file_inode(fd)->i_mode)) {
362 			if (ret < 0 || ret != data_length) {
363 				pr_err("%s() returned %d, expecting %u for "
364 						"S_ISBLK\n", __func__, ret,
365 						data_length);
366 				if (ret >= 0)
367 					ret = -EINVAL;
368 			}
369 		} else {
370 			if (ret < 0) {
371 				pr_err("%s() returned %d for non S_ISBLK\n",
372 						__func__, ret);
373 			} else if (ret != data_length) {
374 				/*
375 				 * Short read case:
376 				 * Probably some one truncate file under us.
377 				 * We must explicitly zero sg-pages to prevent
378 				 * expose uninizialized pages to userspace.
379 				 */
380 				if (ret < data_length)
381 					ret += iov_iter_zero(data_length - ret, &iter);
382 				else
383 					ret = -EINVAL;
384 			}
385 		}
386 	}
387 	kfree(bvec);
388 	return ret;
389 }
390 
391 static sense_reason_t
392 fd_execute_sync_cache(struct se_cmd *cmd)
393 {
394 	struct se_device *dev = cmd->se_dev;
395 	struct fd_dev *fd_dev = FD_DEV(dev);
396 	int immed = (cmd->t_task_cdb[1] & 0x2);
397 	loff_t start, end;
398 	int ret;
399 
400 	/*
401 	 * If the Immediate bit is set, queue up the GOOD response
402 	 * for this SYNCHRONIZE_CACHE op
403 	 */
404 	if (immed)
405 		target_complete_cmd(cmd, SAM_STAT_GOOD);
406 
407 	/*
408 	 * Determine if we will be flushing the entire device.
409 	 */
410 	if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
411 		start = 0;
412 		end = LLONG_MAX;
413 	} else {
414 		start = cmd->t_task_lba * dev->dev_attrib.block_size;
415 		if (cmd->data_length)
416 			end = start + cmd->data_length - 1;
417 		else
418 			end = LLONG_MAX;
419 	}
420 
421 	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
422 	if (ret != 0)
423 		pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
424 
425 	if (immed)
426 		return 0;
427 
428 	if (ret)
429 		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
430 	else
431 		target_complete_cmd(cmd, SAM_STAT_GOOD);
432 
433 	return 0;
434 }
435 
436 static sense_reason_t
437 fd_execute_write_same(struct se_cmd *cmd)
438 {
439 	struct se_device *se_dev = cmd->se_dev;
440 	struct fd_dev *fd_dev = FD_DEV(se_dev);
441 	loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;
442 	sector_t nolb = sbc_get_write_same_sectors(cmd);
443 	struct iov_iter iter;
444 	struct bio_vec *bvec;
445 	unsigned int len = 0, i;
446 	ssize_t ret;
447 
448 	if (!nolb) {
449 		target_complete_cmd(cmd, SAM_STAT_GOOD);
450 		return 0;
451 	}
452 	if (cmd->prot_op) {
453 		pr_err("WRITE_SAME: Protection information with FILEIO"
454 		       " backends not supported\n");
455 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
456 	}
457 
458 	if (cmd->t_data_nents > 1 ||
459 	    cmd->t_data_sg[0].length != cmd->se_dev->dev_attrib.block_size) {
460 		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
461 			" block_size: %u\n",
462 			cmd->t_data_nents,
463 			cmd->t_data_sg[0].length,
464 			cmd->se_dev->dev_attrib.block_size);
465 		return TCM_INVALID_CDB_FIELD;
466 	}
467 
468 	bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
469 	if (!bvec)
470 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
471 
472 	for (i = 0; i < nolb; i++) {
473 		bvec[i].bv_page = sg_page(&cmd->t_data_sg[0]);
474 		bvec[i].bv_len = cmd->t_data_sg[0].length;
475 		bvec[i].bv_offset = cmd->t_data_sg[0].offset;
476 
477 		len += se_dev->dev_attrib.block_size;
478 	}
479 
480 	iov_iter_bvec(&iter, READ, bvec, nolb, len);
481 	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos, 0);
482 
483 	kfree(bvec);
484 	if (ret < 0 || ret != len) {
485 		pr_err("vfs_iter_write() returned %zd for write same\n", ret);
486 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
487 	}
488 
489 	target_complete_cmd(cmd, SAM_STAT_GOOD);
490 	return 0;
491 }
492 
493 static int
494 fd_do_prot_fill(struct se_device *se_dev, sector_t lba, sector_t nolb,
495 		void *buf, size_t bufsize)
496 {
497 	struct fd_dev *fd_dev = FD_DEV(se_dev);
498 	struct file *prot_fd = fd_dev->fd_prot_file;
499 	sector_t prot_length, prot;
500 	loff_t pos = lba * se_dev->prot_length;
501 
502 	if (!prot_fd) {
503 		pr_err("Unable to locate fd_dev->fd_prot_file\n");
504 		return -ENODEV;
505 	}
506 
507 	prot_length = nolb * se_dev->prot_length;
508 
509 	for (prot = 0; prot < prot_length;) {
510 		sector_t len = min_t(sector_t, bufsize, prot_length - prot);
511 		ssize_t ret = kernel_write(prot_fd, buf, len, &pos);
512 
513 		if (ret != len) {
514 			pr_err("vfs_write to prot file failed: %zd\n", ret);
515 			return ret < 0 ? ret : -ENODEV;
516 		}
517 		prot += ret;
518 	}
519 
520 	return 0;
521 }
522 
523 static int
524 fd_do_prot_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
525 {
526 	void *buf;
527 	int rc;
528 
529 	buf = (void *)__get_free_page(GFP_KERNEL);
530 	if (!buf) {
531 		pr_err("Unable to allocate FILEIO prot buf\n");
532 		return -ENOMEM;
533 	}
534 	memset(buf, 0xff, PAGE_SIZE);
535 
536 	rc = fd_do_prot_fill(cmd->se_dev, lba, nolb, buf, PAGE_SIZE);
537 
538 	free_page((unsigned long)buf);
539 
540 	return rc;
541 }
542 
543 static sense_reason_t
544 fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
545 {
546 	struct file *file = FD_DEV(cmd->se_dev)->fd_file;
547 	struct inode *inode = file->f_mapping->host;
548 	int ret;
549 
550 	if (!nolb) {
551 		return 0;
552 	}
553 
554 	if (cmd->se_dev->dev_attrib.pi_prot_type) {
555 		ret = fd_do_prot_unmap(cmd, lba, nolb);
556 		if (ret)
557 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
558 	}
559 
560 	if (S_ISBLK(inode->i_mode)) {
561 		/* The backend is block device, use discard */
562 		struct block_device *bdev = I_BDEV(inode);
563 		struct se_device *dev = cmd->se_dev;
564 
565 		ret = blkdev_issue_discard(bdev,
566 					   target_to_linux_sector(dev, lba),
567 					   target_to_linux_sector(dev,  nolb),
568 					   GFP_KERNEL, 0);
569 		if (ret < 0) {
570 			pr_warn("FILEIO: blkdev_issue_discard() failed: %d\n",
571 				ret);
572 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
573 		}
574 	} else {
575 		/* The backend is normal file, use fallocate */
576 		struct se_device *se_dev = cmd->se_dev;
577 		loff_t pos = lba * se_dev->dev_attrib.block_size;
578 		unsigned int len = nolb * se_dev->dev_attrib.block_size;
579 		int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
580 
581 		if (!file->f_op->fallocate)
582 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
583 
584 		ret = file->f_op->fallocate(file, mode, pos, len);
585 		if (ret < 0) {
586 			pr_warn("FILEIO: fallocate() failed: %d\n", ret);
587 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
588 		}
589 	}
590 
591 	return 0;
592 }
593 
594 static sense_reason_t
595 fd_execute_rw_buffered(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
596 	      enum dma_data_direction data_direction)
597 {
598 	struct se_device *dev = cmd->se_dev;
599 	struct fd_dev *fd_dev = FD_DEV(dev);
600 	struct file *file = fd_dev->fd_file;
601 	struct file *pfile = fd_dev->fd_prot_file;
602 	sense_reason_t rc;
603 	int ret = 0;
604 	/*
605 	 * Call vectorized fileio functions to map struct scatterlist
606 	 * physical memory addresses to struct iovec virtual memory.
607 	 */
608 	if (data_direction == DMA_FROM_DEVICE) {
609 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
610 			ret = fd_do_rw(cmd, pfile, dev->prot_length,
611 				       cmd->t_prot_sg, cmd->t_prot_nents,
612 				       cmd->prot_length, 0);
613 			if (ret < 0)
614 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
615 		}
616 
617 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
618 			       sgl, sgl_nents, cmd->data_length, 0);
619 
620 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type &&
621 		    dev->dev_attrib.pi_prot_verify) {
622 			u32 sectors = cmd->data_length >>
623 					ilog2(dev->dev_attrib.block_size);
624 
625 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
626 					    0, cmd->t_prot_sg, 0);
627 			if (rc)
628 				return rc;
629 		}
630 	} else {
631 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type &&
632 		    dev->dev_attrib.pi_prot_verify) {
633 			u32 sectors = cmd->data_length >>
634 					ilog2(dev->dev_attrib.block_size);
635 
636 			rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors,
637 					    0, cmd->t_prot_sg, 0);
638 			if (rc)
639 				return rc;
640 		}
641 
642 		ret = fd_do_rw(cmd, file, dev->dev_attrib.block_size,
643 			       sgl, sgl_nents, cmd->data_length, 1);
644 		/*
645 		 * Perform implicit vfs_fsync_range() for fd_do_writev() ops
646 		 * for SCSI WRITEs with Forced Unit Access (FUA) set.
647 		 * Allow this to happen independent of WCE=0 setting.
648 		 */
649 		if (ret > 0 && (cmd->se_cmd_flags & SCF_FUA)) {
650 			loff_t start = cmd->t_task_lba *
651 				dev->dev_attrib.block_size;
652 			loff_t end;
653 
654 			if (cmd->data_length)
655 				end = start + cmd->data_length - 1;
656 			else
657 				end = LLONG_MAX;
658 
659 			vfs_fsync_range(fd_dev->fd_file, start, end, 1);
660 		}
661 
662 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {
663 			ret = fd_do_rw(cmd, pfile, dev->prot_length,
664 				       cmd->t_prot_sg, cmd->t_prot_nents,
665 				       cmd->prot_length, 1);
666 			if (ret < 0)
667 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
668 		}
669 	}
670 
671 	if (ret < 0)
672 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
673 
674 	target_complete_cmd(cmd, SAM_STAT_GOOD);
675 	return 0;
676 }
677 
678 static sense_reason_t
679 fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
680 	      enum dma_data_direction data_direction)
681 {
682 	struct se_device *dev = cmd->se_dev;
683 	struct fd_dev *fd_dev = FD_DEV(dev);
684 
685 	/*
686 	 * We are currently limited by the number of iovecs (2048) per
687 	 * single vfs_[writev,readv] call.
688 	 */
689 	if (cmd->data_length > FD_MAX_BYTES) {
690 		pr_err("FILEIO: Not able to process I/O of %u bytes due to"
691 		       "FD_MAX_BYTES: %u iovec count limitation\n",
692 			cmd->data_length, FD_MAX_BYTES);
693 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
694 	}
695 
696 	if (fd_dev->fbd_flags & FDBD_HAS_ASYNC_IO)
697 		return fd_execute_rw_aio(cmd, sgl, sgl_nents, data_direction);
698 	return fd_execute_rw_buffered(cmd, sgl, sgl_nents, data_direction);
699 }
700 
701 enum {
702 	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io,
703 	Opt_fd_async_io, Opt_err
704 };
705 
706 static match_table_t tokens = {
707 	{Opt_fd_dev_name, "fd_dev_name=%s"},
708 	{Opt_fd_dev_size, "fd_dev_size=%s"},
709 	{Opt_fd_buffered_io, "fd_buffered_io=%d"},
710 	{Opt_fd_async_io, "fd_async_io=%d"},
711 	{Opt_err, NULL}
712 };
713 
714 static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
715 		const char *page, ssize_t count)
716 {
717 	struct fd_dev *fd_dev = FD_DEV(dev);
718 	char *orig, *ptr, *arg_p, *opts;
719 	substring_t args[MAX_OPT_ARGS];
720 	int ret = 0, arg, token;
721 
722 	opts = kstrdup(page, GFP_KERNEL);
723 	if (!opts)
724 		return -ENOMEM;
725 
726 	orig = opts;
727 
728 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
729 		if (!*ptr)
730 			continue;
731 
732 		token = match_token(ptr, tokens, args);
733 		switch (token) {
734 		case Opt_fd_dev_name:
735 			if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
736 				FD_MAX_DEV_NAME) == 0) {
737 				ret = -EINVAL;
738 				break;
739 			}
740 			pr_debug("FILEIO: Referencing Path: %s\n",
741 					fd_dev->fd_dev_name);
742 			fd_dev->fbd_flags |= FBDF_HAS_PATH;
743 			break;
744 		case Opt_fd_dev_size:
745 			arg_p = match_strdup(&args[0]);
746 			if (!arg_p) {
747 				ret = -ENOMEM;
748 				break;
749 			}
750 			ret = kstrtoull(arg_p, 0, &fd_dev->fd_dev_size);
751 			kfree(arg_p);
752 			if (ret < 0) {
753 				pr_err("kstrtoull() failed for"
754 						" fd_dev_size=\n");
755 				goto out;
756 			}
757 			pr_debug("FILEIO: Referencing Size: %llu"
758 					" bytes\n", fd_dev->fd_dev_size);
759 			fd_dev->fbd_flags |= FBDF_HAS_SIZE;
760 			break;
761 		case Opt_fd_buffered_io:
762 			ret = match_int(args, &arg);
763 			if (ret)
764 				goto out;
765 			if (arg != 1) {
766 				pr_err("bogus fd_buffered_io=%d value\n", arg);
767 				ret = -EINVAL;
768 				goto out;
769 			}
770 
771 			pr_debug("FILEIO: Using buffered I/O"
772 				" operations for struct fd_dev\n");
773 
774 			fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
775 			break;
776 		case Opt_fd_async_io:
777 			ret = match_int(args, &arg);
778 			if (ret)
779 				goto out;
780 			if (arg != 1) {
781 				pr_err("bogus fd_async_io=%d value\n", arg);
782 				ret = -EINVAL;
783 				goto out;
784 			}
785 
786 			pr_debug("FILEIO: Using async I/O"
787 				" operations for struct fd_dev\n");
788 
789 			fd_dev->fbd_flags |= FDBD_HAS_ASYNC_IO;
790 			break;
791 		default:
792 			break;
793 		}
794 	}
795 
796 out:
797 	kfree(orig);
798 	return (!ret) ? count : ret;
799 }
800 
801 static ssize_t fd_show_configfs_dev_params(struct se_device *dev, char *b)
802 {
803 	struct fd_dev *fd_dev = FD_DEV(dev);
804 	ssize_t bl = 0;
805 
806 	bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
807 	bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s Async: %d\n",
808 		fd_dev->fd_dev_name, fd_dev->fd_dev_size,
809 		(fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) ?
810 		"Buffered-WCE" : "O_DSYNC",
811 		!!(fd_dev->fbd_flags & FDBD_HAS_ASYNC_IO));
812 	return bl;
813 }
814 
815 static sector_t fd_get_blocks(struct se_device *dev)
816 {
817 	struct fd_dev *fd_dev = FD_DEV(dev);
818 	struct file *f = fd_dev->fd_file;
819 	struct inode *i = f->f_mapping->host;
820 	unsigned long long dev_size;
821 	/*
822 	 * When using a file that references an underlying struct block_device,
823 	 * ensure dev_size is always based on the current inode size in order
824 	 * to handle underlying block_device resize operations.
825 	 */
826 	if (S_ISBLK(i->i_mode))
827 		dev_size = i_size_read(i);
828 	else
829 		dev_size = fd_dev->fd_dev_size;
830 
831 	return div_u64(dev_size - dev->dev_attrib.block_size,
832 		       dev->dev_attrib.block_size);
833 }
834 
835 static int fd_init_prot(struct se_device *dev)
836 {
837 	struct fd_dev *fd_dev = FD_DEV(dev);
838 	struct file *prot_file, *file = fd_dev->fd_file;
839 	struct inode *inode;
840 	int ret, flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
841 	char buf[FD_MAX_DEV_PROT_NAME];
842 
843 	if (!file) {
844 		pr_err("Unable to locate fd_dev->fd_file\n");
845 		return -ENODEV;
846 	}
847 
848 	inode = file->f_mapping->host;
849 	if (S_ISBLK(inode->i_mode)) {
850 		pr_err("FILEIO Protection emulation only supported on"
851 		       " !S_ISBLK\n");
852 		return -ENOSYS;
853 	}
854 
855 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE)
856 		flags &= ~O_DSYNC;
857 
858 	snprintf(buf, FD_MAX_DEV_PROT_NAME, "%s.protection",
859 		 fd_dev->fd_dev_name);
860 
861 	prot_file = filp_open(buf, flags, 0600);
862 	if (IS_ERR(prot_file)) {
863 		pr_err("filp_open(%s) failed\n", buf);
864 		ret = PTR_ERR(prot_file);
865 		return ret;
866 	}
867 	fd_dev->fd_prot_file = prot_file;
868 
869 	return 0;
870 }
871 
872 static int fd_format_prot(struct se_device *dev)
873 {
874 	unsigned char *buf;
875 	int unit_size = FDBD_FORMAT_UNIT_SIZE * dev->dev_attrib.block_size;
876 	int ret;
877 
878 	if (!dev->dev_attrib.pi_prot_type) {
879 		pr_err("Unable to format_prot while pi_prot_type == 0\n");
880 		return -ENODEV;
881 	}
882 
883 	buf = vzalloc(unit_size);
884 	if (!buf) {
885 		pr_err("Unable to allocate FILEIO prot buf\n");
886 		return -ENOMEM;
887 	}
888 
889 	pr_debug("Using FILEIO prot_length: %llu\n",
890 		 (unsigned long long)(dev->transport->get_blocks(dev) + 1) *
891 					dev->prot_length);
892 
893 	memset(buf, 0xff, unit_size);
894 	ret = fd_do_prot_fill(dev, 0, dev->transport->get_blocks(dev) + 1,
895 			      buf, unit_size);
896 	vfree(buf);
897 	return ret;
898 }
899 
900 static void fd_free_prot(struct se_device *dev)
901 {
902 	struct fd_dev *fd_dev = FD_DEV(dev);
903 
904 	if (!fd_dev->fd_prot_file)
905 		return;
906 
907 	filp_close(fd_dev->fd_prot_file, NULL);
908 	fd_dev->fd_prot_file = NULL;
909 }
910 
911 static struct sbc_ops fd_sbc_ops = {
912 	.execute_rw		= fd_execute_rw,
913 	.execute_sync_cache	= fd_execute_sync_cache,
914 	.execute_write_same	= fd_execute_write_same,
915 	.execute_unmap		= fd_execute_unmap,
916 };
917 
918 static sense_reason_t
919 fd_parse_cdb(struct se_cmd *cmd)
920 {
921 	return sbc_parse_cdb(cmd, &fd_sbc_ops);
922 }
923 
924 static const struct target_backend_ops fileio_ops = {
925 	.name			= "fileio",
926 	.inquiry_prod		= "FILEIO",
927 	.inquiry_rev		= FD_VERSION,
928 	.owner			= THIS_MODULE,
929 	.attach_hba		= fd_attach_hba,
930 	.detach_hba		= fd_detach_hba,
931 	.alloc_device		= fd_alloc_device,
932 	.configure_device	= fd_configure_device,
933 	.destroy_device		= fd_destroy_device,
934 	.free_device		= fd_free_device,
935 	.parse_cdb		= fd_parse_cdb,
936 	.set_configfs_dev_params = fd_set_configfs_dev_params,
937 	.show_configfs_dev_params = fd_show_configfs_dev_params,
938 	.get_device_type	= sbc_get_device_type,
939 	.get_blocks		= fd_get_blocks,
940 	.init_prot		= fd_init_prot,
941 	.format_prot		= fd_format_prot,
942 	.free_prot		= fd_free_prot,
943 	.tb_dev_attrib_attrs	= sbc_attrib_attrs,
944 };
945 
946 static int __init fileio_module_init(void)
947 {
948 	return transport_backend_register(&fileio_ops);
949 }
950 
951 static void __exit fileio_module_exit(void)
952 {
953 	target_backend_unregister(&fileio_ops);
954 }
955 
956 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
957 MODULE_AUTHOR("nab@Linux-iSCSI.org");
958 MODULE_LICENSE("GPL");
959 
960 module_init(fileio_module_init);
961 module_exit(fileio_module_exit);
962