xref: /linux/drivers/target/target_core_file.c (revision 97f0b13452198290799fd6780f05fbaa74f927d3)
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/falloc.h>
34 #include <scsi/scsi_proto.h>
35 #include <asm/unaligned.h>
36 
37 #include <target/target_core_base.h>
38 #include <target/target_core_backend.h>
39 #include <target/target_core_backend_configfs.h>
40 
41 #include "target_core_file.h"
42 
43 static inline struct fd_dev *FD_DEV(struct se_device *dev)
44 {
45 	return container_of(dev, struct fd_dev, dev);
46 }
47 
48 /*	fd_attach_hba(): (Part of se_subsystem_api_t template)
49  *
50  *
51  */
52 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
53 {
54 	struct fd_host *fd_host;
55 
56 	fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
57 	if (!fd_host) {
58 		pr_err("Unable to allocate memory for struct fd_host\n");
59 		return -ENOMEM;
60 	}
61 
62 	fd_host->fd_host_id = host_id;
63 
64 	hba->hba_ptr = fd_host;
65 
66 	pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
67 		" Target Core Stack %s\n", hba->hba_id, FD_VERSION,
68 		TARGET_CORE_MOD_VERSION);
69 	pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic\n",
70 		hba->hba_id, fd_host->fd_host_id);
71 
72 	return 0;
73 }
74 
75 static void fd_detach_hba(struct se_hba *hba)
76 {
77 	struct fd_host *fd_host = hba->hba_ptr;
78 
79 	pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
80 		" Target Core\n", hba->hba_id, fd_host->fd_host_id);
81 
82 	kfree(fd_host);
83 	hba->hba_ptr = NULL;
84 }
85 
86 static struct se_device *fd_alloc_device(struct se_hba *hba, const char *name)
87 {
88 	struct fd_dev *fd_dev;
89 	struct fd_host *fd_host = hba->hba_ptr;
90 
91 	fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
92 	if (!fd_dev) {
93 		pr_err("Unable to allocate memory for struct fd_dev\n");
94 		return NULL;
95 	}
96 
97 	fd_dev->fd_host = fd_host;
98 
99 	pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
100 
101 	return &fd_dev->dev;
102 }
103 
104 static int fd_configure_device(struct se_device *dev)
105 {
106 	struct fd_dev *fd_dev = FD_DEV(dev);
107 	struct fd_host *fd_host = dev->se_hba->hba_ptr;
108 	struct file *file;
109 	struct inode *inode = NULL;
110 	int flags, ret = -EINVAL;
111 
112 	if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
113 		pr_err("Missing fd_dev_name=\n");
114 		return -EINVAL;
115 	}
116 
117 	/*
118 	 * Use O_DSYNC by default instead of O_SYNC to forgo syncing
119 	 * of pure timestamp updates.
120 	 */
121 	flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
122 
123 	/*
124 	 * Optionally allow fd_buffered_io=1 to be enabled for people
125 	 * who want use the fs buffer cache as an WriteCache mechanism.
126 	 *
127 	 * This means that in event of a hard failure, there is a risk
128 	 * of silent data-loss if the SCSI client has *not* performed a
129 	 * forced unit access (FUA) write, or issued SYNCHRONIZE_CACHE
130 	 * to write-out the entire device cache.
131 	 */
132 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
133 		pr_debug("FILEIO: Disabling O_DSYNC, using buffered FILEIO\n");
134 		flags &= ~O_DSYNC;
135 	}
136 
137 	file = filp_open(fd_dev->fd_dev_name, flags, 0600);
138 	if (IS_ERR(file)) {
139 		pr_err("filp_open(%s) failed\n", fd_dev->fd_dev_name);
140 		ret = PTR_ERR(file);
141 		goto fail;
142 	}
143 	fd_dev->fd_file = file;
144 	/*
145 	 * If using a block backend with this struct file, we extract
146 	 * fd_dev->fd_[block,dev]_size from struct block_device.
147 	 *
148 	 * Otherwise, we use the passed fd_size= from configfs
149 	 */
150 	inode = file->f_mapping->host;
151 	if (S_ISBLK(inode->i_mode)) {
152 		struct request_queue *q = bdev_get_queue(inode->i_bdev);
153 		unsigned long long dev_size;
154 
155 		fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
156 		/*
157 		 * Determine the number of bytes from i_size_read() minus
158 		 * one (1) logical sector from underlying struct block_device
159 		 */
160 		dev_size = (i_size_read(file->f_mapping->host) -
161 				       fd_dev->fd_block_size);
162 
163 		pr_debug("FILEIO: Using size: %llu bytes from struct"
164 			" block_device blocks: %llu logical_block_size: %d\n",
165 			dev_size, div_u64(dev_size, fd_dev->fd_block_size),
166 			fd_dev->fd_block_size);
167 		/*
168 		 * Check if the underlying struct block_device request_queue supports
169 		 * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
170 		 * in ATA and we need to set TPE=1
171 		 */
172 		if (blk_queue_discard(q)) {
173 			dev->dev_attrib.max_unmap_lba_count =
174 				q->limits.max_discard_sectors;
175 			/*
176 			 * Currently hardcoded to 1 in Linux/SCSI code..
177 			 */
178 			dev->dev_attrib.max_unmap_block_desc_count = 1;
179 			dev->dev_attrib.unmap_granularity =
180 				q->limits.discard_granularity >> 9;
181 			dev->dev_attrib.unmap_granularity_alignment =
182 				q->limits.discard_alignment;
183 			pr_debug("IFILE: BLOCK Discard support available,"
184 					" disabled by default\n");
185 		}
186 		/*
187 		 * Enable write same emulation for IBLOCK and use 0xFFFF as
188 		 * the smaller WRITE_SAME(10) only has a two-byte block count.
189 		 */
190 		dev->dev_attrib.max_write_same_len = 0xFFFF;
191 
192 		if (blk_queue_nonrot(q))
193 			dev->dev_attrib.is_nonrot = 1;
194 	} else {
195 		if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
196 			pr_err("FILEIO: Missing fd_dev_size="
197 				" parameter, and no backing struct"
198 				" block_device\n");
199 			goto fail;
200 		}
201 
202 		fd_dev->fd_block_size = FD_BLOCKSIZE;
203 		/*
204 		 * Limit UNMAP emulation to 8k Number of LBAs (NoLB)
205 		 */
206 		dev->dev_attrib.max_unmap_lba_count = 0x2000;
207 		/*
208 		 * Currently hardcoded to 1 in Linux/SCSI code..
209 		 */
210 		dev->dev_attrib.max_unmap_block_desc_count = 1;
211 		dev->dev_attrib.unmap_granularity = 1;
212 		dev->dev_attrib.unmap_granularity_alignment = 0;
213 
214 		/*
215 		 * Limit WRITE_SAME w/ UNMAP=0 emulation to 8k Number of LBAs (NoLB)
216 		 * based upon struct iovec limit for vfs_writev()
217 		 */
218 		dev->dev_attrib.max_write_same_len = 0x1000;
219 	}
220 
221 	dev->dev_attrib.hw_block_size = fd_dev->fd_block_size;
222 	dev->dev_attrib.max_bytes_per_io = FD_MAX_BYTES;
223 	dev->dev_attrib.hw_max_sectors = FD_MAX_BYTES / fd_dev->fd_block_size;
224 	dev->dev_attrib.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
225 
226 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE) {
227 		pr_debug("FILEIO: Forcing setting of emulate_write_cache=1"
228 			" with FDBD_HAS_BUFFERED_IO_WCE\n");
229 		dev->dev_attrib.emulate_write_cache = 1;
230 	}
231 
232 	fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
233 	fd_dev->fd_queue_depth = dev->queue_depth;
234 
235 	pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
236 		" %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
237 			fd_dev->fd_dev_name, fd_dev->fd_dev_size);
238 
239 	return 0;
240 fail:
241 	if (fd_dev->fd_file) {
242 		filp_close(fd_dev->fd_file, NULL);
243 		fd_dev->fd_file = NULL;
244 	}
245 	return ret;
246 }
247 
248 static void fd_free_device(struct se_device *dev)
249 {
250 	struct fd_dev *fd_dev = FD_DEV(dev);
251 
252 	if (fd_dev->fd_file) {
253 		filp_close(fd_dev->fd_file, NULL);
254 		fd_dev->fd_file = NULL;
255 	}
256 
257 	kfree(fd_dev);
258 }
259 
260 static int fd_do_prot_rw(struct se_cmd *cmd, struct fd_prot *fd_prot,
261 			 int is_write)
262 {
263 	struct se_device *se_dev = cmd->se_dev;
264 	struct fd_dev *dev = FD_DEV(se_dev);
265 	struct file *prot_fd = dev->fd_prot_file;
266 	loff_t pos = (cmd->t_task_lba * se_dev->prot_length);
267 	unsigned char *buf;
268 	u32 prot_size;
269 	int rc, ret = 1;
270 
271 	prot_size = (cmd->data_length / se_dev->dev_attrib.block_size) *
272 		     se_dev->prot_length;
273 
274 	if (!is_write) {
275 		fd_prot->prot_buf = kzalloc(prot_size, GFP_KERNEL);
276 		if (!fd_prot->prot_buf) {
277 			pr_err("Unable to allocate fd_prot->prot_buf\n");
278 			return -ENOMEM;
279 		}
280 		buf = fd_prot->prot_buf;
281 
282 		fd_prot->prot_sg_nents = 1;
283 		fd_prot->prot_sg = kzalloc(sizeof(struct scatterlist),
284 					   GFP_KERNEL);
285 		if (!fd_prot->prot_sg) {
286 			pr_err("Unable to allocate fd_prot->prot_sg\n");
287 			kfree(fd_prot->prot_buf);
288 			return -ENOMEM;
289 		}
290 		sg_init_table(fd_prot->prot_sg, fd_prot->prot_sg_nents);
291 		sg_set_buf(fd_prot->prot_sg, buf, prot_size);
292 	}
293 
294 	if (is_write) {
295 		rc = kernel_write(prot_fd, fd_prot->prot_buf, prot_size, pos);
296 		if (rc < 0 || prot_size != rc) {
297 			pr_err("kernel_write() for fd_do_prot_rw failed:"
298 			       " %d\n", rc);
299 			ret = -EINVAL;
300 		}
301 	} else {
302 		rc = kernel_read(prot_fd, pos, fd_prot->prot_buf, prot_size);
303 		if (rc < 0) {
304 			pr_err("kernel_read() for fd_do_prot_rw failed:"
305 			       " %d\n", rc);
306 			ret = -EINVAL;
307 		}
308 	}
309 
310 	if (is_write || ret < 0) {
311 		kfree(fd_prot->prot_sg);
312 		kfree(fd_prot->prot_buf);
313 	}
314 
315 	return ret;
316 }
317 
318 static int fd_do_rw(struct se_cmd *cmd, struct scatterlist *sgl,
319 		u32 sgl_nents, int is_write)
320 {
321 	struct se_device *se_dev = cmd->se_dev;
322 	struct fd_dev *dev = FD_DEV(se_dev);
323 	struct file *fd = dev->fd_file;
324 	struct scatterlist *sg;
325 	struct iov_iter iter;
326 	struct bio_vec *bvec;
327 	ssize_t len = 0;
328 	loff_t pos = (cmd->t_task_lba * se_dev->dev_attrib.block_size);
329 	int ret = 0, i;
330 
331 	bvec = kcalloc(sgl_nents, sizeof(struct bio_vec), GFP_KERNEL);
332 	if (!bvec) {
333 		pr_err("Unable to allocate fd_do_readv iov[]\n");
334 		return -ENOMEM;
335 	}
336 
337 	for_each_sg(sgl, sg, sgl_nents, i) {
338 		bvec[i].bv_page = sg_page(sg);
339 		bvec[i].bv_len = sg->length;
340 		bvec[i].bv_offset = sg->offset;
341 
342 		len += sg->length;
343 	}
344 
345 	iov_iter_bvec(&iter, ITER_BVEC, bvec, sgl_nents, len);
346 	if (is_write)
347 		ret = vfs_iter_write(fd, &iter, &pos);
348 	else
349 		ret = vfs_iter_read(fd, &iter, &pos);
350 
351 	kfree(bvec);
352 
353 	if (is_write) {
354 		if (ret < 0 || ret != cmd->data_length) {
355 			pr_err("%s() write returned %d\n", __func__, ret);
356 			return (ret < 0 ? ret : -EINVAL);
357 		}
358 	} else {
359 		/*
360 		 * Return zeros and GOOD status even if the READ did not return
361 		 * the expected virt_size for struct file w/o a backing struct
362 		 * block_device.
363 		 */
364 		if (S_ISBLK(file_inode(fd)->i_mode)) {
365 			if (ret < 0 || ret != cmd->data_length) {
366 				pr_err("%s() returned %d, expecting %u for "
367 						"S_ISBLK\n", __func__, ret,
368 						cmd->data_length);
369 				return (ret < 0 ? ret : -EINVAL);
370 			}
371 		} else {
372 			if (ret < 0) {
373 				pr_err("%s() returned %d for non S_ISBLK\n",
374 						__func__, ret);
375 				return ret;
376 			}
377 		}
378 	}
379 	return 1;
380 }
381 
382 static sense_reason_t
383 fd_execute_sync_cache(struct se_cmd *cmd)
384 {
385 	struct se_device *dev = cmd->se_dev;
386 	struct fd_dev *fd_dev = FD_DEV(dev);
387 	int immed = (cmd->t_task_cdb[1] & 0x2);
388 	loff_t start, end;
389 	int ret;
390 
391 	/*
392 	 * If the Immediate bit is set, queue up the GOOD response
393 	 * for this SYNCHRONIZE_CACHE op
394 	 */
395 	if (immed)
396 		target_complete_cmd(cmd, SAM_STAT_GOOD);
397 
398 	/*
399 	 * Determine if we will be flushing the entire device.
400 	 */
401 	if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
402 		start = 0;
403 		end = LLONG_MAX;
404 	} else {
405 		start = cmd->t_task_lba * dev->dev_attrib.block_size;
406 		if (cmd->data_length)
407 			end = start + cmd->data_length - 1;
408 		else
409 			end = LLONG_MAX;
410 	}
411 
412 	ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
413 	if (ret != 0)
414 		pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
415 
416 	if (immed)
417 		return 0;
418 
419 	if (ret)
420 		target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
421 	else
422 		target_complete_cmd(cmd, SAM_STAT_GOOD);
423 
424 	return 0;
425 }
426 
427 static sense_reason_t
428 fd_execute_write_same(struct se_cmd *cmd)
429 {
430 	struct se_device *se_dev = cmd->se_dev;
431 	struct fd_dev *fd_dev = FD_DEV(se_dev);
432 	loff_t pos = cmd->t_task_lba * se_dev->dev_attrib.block_size;
433 	sector_t nolb = sbc_get_write_same_sectors(cmd);
434 	struct iov_iter iter;
435 	struct bio_vec *bvec;
436 	unsigned int len = 0, i;
437 	ssize_t ret;
438 
439 	if (!nolb) {
440 		target_complete_cmd(cmd, SAM_STAT_GOOD);
441 		return 0;
442 	}
443 	if (cmd->prot_op) {
444 		pr_err("WRITE_SAME: Protection information with FILEIO"
445 		       " backends not supported\n");
446 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
447 	}
448 
449 	if (cmd->t_data_nents > 1 ||
450 	    cmd->t_data_sg[0].length != cmd->se_dev->dev_attrib.block_size) {
451 		pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
452 			" block_size: %u\n",
453 			cmd->t_data_nents,
454 			cmd->t_data_sg[0].length,
455 			cmd->se_dev->dev_attrib.block_size);
456 		return TCM_INVALID_CDB_FIELD;
457 	}
458 
459 	bvec = kcalloc(nolb, sizeof(struct bio_vec), GFP_KERNEL);
460 	if (!bvec)
461 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
462 
463 	for (i = 0; i < nolb; i++) {
464 		bvec[i].bv_page = sg_page(&cmd->t_data_sg[0]);
465 		bvec[i].bv_len = cmd->t_data_sg[0].length;
466 		bvec[i].bv_offset = cmd->t_data_sg[0].offset;
467 
468 		len += se_dev->dev_attrib.block_size;
469 	}
470 
471 	iov_iter_bvec(&iter, ITER_BVEC, bvec, nolb, len);
472 	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos);
473 
474 	kfree(bvec);
475 	if (ret < 0 || ret != len) {
476 		pr_err("vfs_iter_write() returned %zd for write same\n", ret);
477 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
478 	}
479 
480 	target_complete_cmd(cmd, SAM_STAT_GOOD);
481 	return 0;
482 }
483 
484 static int
485 fd_do_prot_fill(struct se_device *se_dev, sector_t lba, sector_t nolb,
486 		void *buf, size_t bufsize)
487 {
488 	struct fd_dev *fd_dev = FD_DEV(se_dev);
489 	struct file *prot_fd = fd_dev->fd_prot_file;
490 	sector_t prot_length, prot;
491 	loff_t pos = lba * se_dev->prot_length;
492 
493 	if (!prot_fd) {
494 		pr_err("Unable to locate fd_dev->fd_prot_file\n");
495 		return -ENODEV;
496 	}
497 
498 	prot_length = nolb * se_dev->prot_length;
499 
500 	for (prot = 0; prot < prot_length;) {
501 		sector_t len = min_t(sector_t, bufsize, prot_length - prot);
502 		ssize_t ret = kernel_write(prot_fd, buf, len, pos + prot);
503 
504 		if (ret != len) {
505 			pr_err("vfs_write to prot file failed: %zd\n", ret);
506 			return ret < 0 ? ret : -ENODEV;
507 		}
508 		prot += ret;
509 	}
510 
511 	return 0;
512 }
513 
514 static int
515 fd_do_prot_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
516 {
517 	void *buf;
518 	int rc;
519 
520 	buf = (void *)__get_free_page(GFP_KERNEL);
521 	if (!buf) {
522 		pr_err("Unable to allocate FILEIO prot buf\n");
523 		return -ENOMEM;
524 	}
525 	memset(buf, 0xff, PAGE_SIZE);
526 
527 	rc = fd_do_prot_fill(cmd->se_dev, lba, nolb, buf, PAGE_SIZE);
528 
529 	free_page((unsigned long)buf);
530 
531 	return rc;
532 }
533 
534 static sense_reason_t
535 fd_do_unmap(struct se_cmd *cmd, void *priv, sector_t lba, sector_t nolb)
536 {
537 	struct file *file = priv;
538 	struct inode *inode = file->f_mapping->host;
539 	int ret;
540 
541 	if (cmd->se_dev->dev_attrib.pi_prot_type) {
542 		ret = fd_do_prot_unmap(cmd, lba, nolb);
543 		if (ret)
544 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
545 	}
546 
547 	if (S_ISBLK(inode->i_mode)) {
548 		/* The backend is block device, use discard */
549 		struct block_device *bdev = inode->i_bdev;
550 
551 		ret = blkdev_issue_discard(bdev, lba,
552 				nolb, GFP_KERNEL, 0);
553 		if (ret < 0) {
554 			pr_warn("FILEIO: blkdev_issue_discard() failed: %d\n",
555 				ret);
556 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
557 		}
558 	} else {
559 		/* The backend is normal file, use fallocate */
560 		struct se_device *se_dev = cmd->se_dev;
561 		loff_t pos = lba * se_dev->dev_attrib.block_size;
562 		unsigned int len = nolb * se_dev->dev_attrib.block_size;
563 		int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
564 
565 		if (!file->f_op->fallocate)
566 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
567 
568 		ret = file->f_op->fallocate(file, mode, pos, len);
569 		if (ret < 0) {
570 			pr_warn("FILEIO: fallocate() failed: %d\n", ret);
571 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
572 		}
573 	}
574 
575 	return 0;
576 }
577 
578 static sense_reason_t
579 fd_execute_write_same_unmap(struct se_cmd *cmd)
580 {
581 	struct se_device *se_dev = cmd->se_dev;
582 	struct fd_dev *fd_dev = FD_DEV(se_dev);
583 	struct file *file = fd_dev->fd_file;
584 	sector_t lba = cmd->t_task_lba;
585 	sector_t nolb = sbc_get_write_same_sectors(cmd);
586 	sense_reason_t ret;
587 
588 	if (!nolb) {
589 		target_complete_cmd(cmd, SAM_STAT_GOOD);
590 		return 0;
591 	}
592 
593 	ret = fd_do_unmap(cmd, file, lba, nolb);
594 	if (ret)
595 		return ret;
596 
597 	target_complete_cmd(cmd, GOOD);
598 	return 0;
599 }
600 
601 static sense_reason_t
602 fd_execute_unmap(struct se_cmd *cmd)
603 {
604 	struct file *file = FD_DEV(cmd->se_dev)->fd_file;
605 
606 	return sbc_execute_unmap(cmd, fd_do_unmap, file);
607 }
608 
609 static sense_reason_t
610 fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
611 	      enum dma_data_direction data_direction)
612 {
613 	struct se_device *dev = cmd->se_dev;
614 	struct fd_prot fd_prot;
615 	sense_reason_t rc;
616 	int ret = 0;
617 	/*
618 	 * We are currently limited by the number of iovecs (2048) per
619 	 * single vfs_[writev,readv] call.
620 	 */
621 	if (cmd->data_length > FD_MAX_BYTES) {
622 		pr_err("FILEIO: Not able to process I/O of %u bytes due to"
623 		       "FD_MAX_BYTES: %u iovec count limitiation\n",
624 			cmd->data_length, FD_MAX_BYTES);
625 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
626 	}
627 	/*
628 	 * Call vectorized fileio functions to map struct scatterlist
629 	 * physical memory addresses to struct iovec virtual memory.
630 	 */
631 	if (data_direction == DMA_FROM_DEVICE) {
632 		memset(&fd_prot, 0, sizeof(struct fd_prot));
633 
634 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
635 			ret = fd_do_prot_rw(cmd, &fd_prot, false);
636 			if (ret < 0)
637 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
638 		}
639 
640 		ret = fd_do_rw(cmd, sgl, sgl_nents, 0);
641 
642 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {
643 			u32 sectors = cmd->data_length / dev->dev_attrib.block_size;
644 
645 			rc = sbc_dif_verify_read(cmd, cmd->t_task_lba, sectors,
646 						 0, fd_prot.prot_sg, 0);
647 			if (rc) {
648 				kfree(fd_prot.prot_sg);
649 				kfree(fd_prot.prot_buf);
650 				return rc;
651 			}
652 			kfree(fd_prot.prot_sg);
653 			kfree(fd_prot.prot_buf);
654 		}
655 	} else {
656 		memset(&fd_prot, 0, sizeof(struct fd_prot));
657 
658 		if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
659 			u32 sectors = cmd->data_length / dev->dev_attrib.block_size;
660 
661 			ret = fd_do_prot_rw(cmd, &fd_prot, false);
662 			if (ret < 0)
663 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
664 
665 			rc = sbc_dif_verify_write(cmd, cmd->t_task_lba, sectors,
666 						  0, fd_prot.prot_sg, 0);
667 			if (rc) {
668 				kfree(fd_prot.prot_sg);
669 				kfree(fd_prot.prot_buf);
670 				return rc;
671 			}
672 		}
673 
674 		ret = fd_do_rw(cmd, sgl, sgl_nents, 1);
675 		/*
676 		 * Perform implicit vfs_fsync_range() for fd_do_writev() ops
677 		 * for SCSI WRITEs with Forced Unit Access (FUA) set.
678 		 * Allow this to happen independent of WCE=0 setting.
679 		 */
680 		if (ret > 0 &&
681 		    dev->dev_attrib.emulate_fua_write > 0 &&
682 		    (cmd->se_cmd_flags & SCF_FUA)) {
683 			struct fd_dev *fd_dev = FD_DEV(dev);
684 			loff_t start = cmd->t_task_lba *
685 				dev->dev_attrib.block_size;
686 			loff_t end;
687 
688 			if (cmd->data_length)
689 				end = start + cmd->data_length - 1;
690 			else
691 				end = LLONG_MAX;
692 
693 			vfs_fsync_range(fd_dev->fd_file, start, end, 1);
694 		}
695 
696 		if (ret > 0 && cmd->prot_type && dev->dev_attrib.pi_prot_type) {
697 			ret = fd_do_prot_rw(cmd, &fd_prot, true);
698 			if (ret < 0)
699 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
700 		}
701 	}
702 
703 	if (ret < 0) {
704 		kfree(fd_prot.prot_sg);
705 		kfree(fd_prot.prot_buf);
706 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
707 	}
708 
709 	if (ret)
710 		target_complete_cmd(cmd, SAM_STAT_GOOD);
711 	return 0;
712 }
713 
714 enum {
715 	Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
716 };
717 
718 static match_table_t tokens = {
719 	{Opt_fd_dev_name, "fd_dev_name=%s"},
720 	{Opt_fd_dev_size, "fd_dev_size=%s"},
721 	{Opt_fd_buffered_io, "fd_buffered_io=%d"},
722 	{Opt_err, NULL}
723 };
724 
725 static ssize_t fd_set_configfs_dev_params(struct se_device *dev,
726 		const char *page, ssize_t count)
727 {
728 	struct fd_dev *fd_dev = FD_DEV(dev);
729 	char *orig, *ptr, *arg_p, *opts;
730 	substring_t args[MAX_OPT_ARGS];
731 	int ret = 0, arg, token;
732 
733 	opts = kstrdup(page, GFP_KERNEL);
734 	if (!opts)
735 		return -ENOMEM;
736 
737 	orig = opts;
738 
739 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
740 		if (!*ptr)
741 			continue;
742 
743 		token = match_token(ptr, tokens, args);
744 		switch (token) {
745 		case Opt_fd_dev_name:
746 			if (match_strlcpy(fd_dev->fd_dev_name, &args[0],
747 				FD_MAX_DEV_NAME) == 0) {
748 				ret = -EINVAL;
749 				break;
750 			}
751 			pr_debug("FILEIO: Referencing Path: %s\n",
752 					fd_dev->fd_dev_name);
753 			fd_dev->fbd_flags |= FBDF_HAS_PATH;
754 			break;
755 		case Opt_fd_dev_size:
756 			arg_p = match_strdup(&args[0]);
757 			if (!arg_p) {
758 				ret = -ENOMEM;
759 				break;
760 			}
761 			ret = kstrtoull(arg_p, 0, &fd_dev->fd_dev_size);
762 			kfree(arg_p);
763 			if (ret < 0) {
764 				pr_err("kstrtoull() failed for"
765 						" fd_dev_size=\n");
766 				goto out;
767 			}
768 			pr_debug("FILEIO: Referencing Size: %llu"
769 					" bytes\n", fd_dev->fd_dev_size);
770 			fd_dev->fbd_flags |= FBDF_HAS_SIZE;
771 			break;
772 		case Opt_fd_buffered_io:
773 			ret = match_int(args, &arg);
774 			if (ret)
775 				goto out;
776 			if (arg != 1) {
777 				pr_err("bogus fd_buffered_io=%d value\n", arg);
778 				ret = -EINVAL;
779 				goto out;
780 			}
781 
782 			pr_debug("FILEIO: Using buffered I/O"
783 				" operations for struct fd_dev\n");
784 
785 			fd_dev->fbd_flags |= FDBD_HAS_BUFFERED_IO_WCE;
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\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 	return bl;
808 }
809 
810 static sector_t fd_get_blocks(struct se_device *dev)
811 {
812 	struct fd_dev *fd_dev = FD_DEV(dev);
813 	struct file *f = fd_dev->fd_file;
814 	struct inode *i = f->f_mapping->host;
815 	unsigned long long dev_size;
816 	/*
817 	 * When using a file that references an underlying struct block_device,
818 	 * ensure dev_size is always based on the current inode size in order
819 	 * to handle underlying block_device resize operations.
820 	 */
821 	if (S_ISBLK(i->i_mode))
822 		dev_size = i_size_read(i);
823 	else
824 		dev_size = fd_dev->fd_dev_size;
825 
826 	return div_u64(dev_size - dev->dev_attrib.block_size,
827 		       dev->dev_attrib.block_size);
828 }
829 
830 static int fd_init_prot(struct se_device *dev)
831 {
832 	struct fd_dev *fd_dev = FD_DEV(dev);
833 	struct file *prot_file, *file = fd_dev->fd_file;
834 	struct inode *inode;
835 	int ret, flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC;
836 	char buf[FD_MAX_DEV_PROT_NAME];
837 
838 	if (!file) {
839 		pr_err("Unable to locate fd_dev->fd_file\n");
840 		return -ENODEV;
841 	}
842 
843 	inode = file->f_mapping->host;
844 	if (S_ISBLK(inode->i_mode)) {
845 		pr_err("FILEIO Protection emulation only supported on"
846 		       " !S_ISBLK\n");
847 		return -ENOSYS;
848 	}
849 
850 	if (fd_dev->fbd_flags & FDBD_HAS_BUFFERED_IO_WCE)
851 		flags &= ~O_DSYNC;
852 
853 	snprintf(buf, FD_MAX_DEV_PROT_NAME, "%s.protection",
854 		 fd_dev->fd_dev_name);
855 
856 	prot_file = filp_open(buf, flags, 0600);
857 	if (IS_ERR(prot_file)) {
858 		pr_err("filp_open(%s) failed\n", buf);
859 		ret = PTR_ERR(prot_file);
860 		return ret;
861 	}
862 	fd_dev->fd_prot_file = prot_file;
863 
864 	return 0;
865 }
866 
867 static int fd_format_prot(struct se_device *dev)
868 {
869 	unsigned char *buf;
870 	int unit_size = FDBD_FORMAT_UNIT_SIZE * dev->dev_attrib.block_size;
871 	int ret;
872 
873 	if (!dev->dev_attrib.pi_prot_type) {
874 		pr_err("Unable to format_prot while pi_prot_type == 0\n");
875 		return -ENODEV;
876 	}
877 
878 	buf = vzalloc(unit_size);
879 	if (!buf) {
880 		pr_err("Unable to allocate FILEIO prot buf\n");
881 		return -ENOMEM;
882 	}
883 
884 	pr_debug("Using FILEIO prot_length: %llu\n",
885 		 (unsigned long long)(dev->transport->get_blocks(dev) + 1) *
886 					dev->prot_length);
887 
888 	memset(buf, 0xff, unit_size);
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_write_same_unmap = fd_execute_write_same_unmap,
911 	.execute_unmap		= fd_execute_unmap,
912 };
913 
914 static sense_reason_t
915 fd_parse_cdb(struct se_cmd *cmd)
916 {
917 	return sbc_parse_cdb(cmd, &fd_sbc_ops);
918 }
919 
920 DEF_TB_DEFAULT_ATTRIBS(fileio);
921 
922 static struct configfs_attribute *fileio_backend_dev_attrs[] = {
923 	&fileio_dev_attrib_emulate_model_alias.attr,
924 	&fileio_dev_attrib_emulate_dpo.attr,
925 	&fileio_dev_attrib_emulate_fua_write.attr,
926 	&fileio_dev_attrib_emulate_fua_read.attr,
927 	&fileio_dev_attrib_emulate_write_cache.attr,
928 	&fileio_dev_attrib_emulate_ua_intlck_ctrl.attr,
929 	&fileio_dev_attrib_emulate_tas.attr,
930 	&fileio_dev_attrib_emulate_tpu.attr,
931 	&fileio_dev_attrib_emulate_tpws.attr,
932 	&fileio_dev_attrib_emulate_caw.attr,
933 	&fileio_dev_attrib_emulate_3pc.attr,
934 	&fileio_dev_attrib_pi_prot_type.attr,
935 	&fileio_dev_attrib_hw_pi_prot_type.attr,
936 	&fileio_dev_attrib_pi_prot_format.attr,
937 	&fileio_dev_attrib_enforce_pr_isids.attr,
938 	&fileio_dev_attrib_is_nonrot.attr,
939 	&fileio_dev_attrib_emulate_rest_reord.attr,
940 	&fileio_dev_attrib_force_pr_aptpl.attr,
941 	&fileio_dev_attrib_hw_block_size.attr,
942 	&fileio_dev_attrib_block_size.attr,
943 	&fileio_dev_attrib_hw_max_sectors.attr,
944 	&fileio_dev_attrib_optimal_sectors.attr,
945 	&fileio_dev_attrib_hw_queue_depth.attr,
946 	&fileio_dev_attrib_queue_depth.attr,
947 	&fileio_dev_attrib_max_unmap_lba_count.attr,
948 	&fileio_dev_attrib_max_unmap_block_desc_count.attr,
949 	&fileio_dev_attrib_unmap_granularity.attr,
950 	&fileio_dev_attrib_unmap_granularity_alignment.attr,
951 	&fileio_dev_attrib_max_write_same_len.attr,
952 	NULL,
953 };
954 
955 static struct se_subsystem_api fileio_template = {
956 	.name			= "fileio",
957 	.inquiry_prod		= "FILEIO",
958 	.inquiry_rev		= FD_VERSION,
959 	.owner			= THIS_MODULE,
960 	.attach_hba		= fd_attach_hba,
961 	.detach_hba		= fd_detach_hba,
962 	.alloc_device		= fd_alloc_device,
963 	.configure_device	= fd_configure_device,
964 	.free_device		= fd_free_device,
965 	.parse_cdb		= fd_parse_cdb,
966 	.set_configfs_dev_params = fd_set_configfs_dev_params,
967 	.show_configfs_dev_params = fd_show_configfs_dev_params,
968 	.get_device_type	= sbc_get_device_type,
969 	.get_blocks		= fd_get_blocks,
970 	.init_prot		= fd_init_prot,
971 	.format_prot		= fd_format_prot,
972 	.free_prot		= fd_free_prot,
973 };
974 
975 static int __init fileio_module_init(void)
976 {
977 	struct target_backend_cits *tbc = &fileio_template.tb_cits;
978 
979 	target_core_setup_sub_cits(&fileio_template);
980 	tbc->tb_dev_attrib_cit.ct_attrs = fileio_backend_dev_attrs;
981 
982 	return transport_subsystem_register(&fileio_template);
983 }
984 
985 static void __exit fileio_module_exit(void)
986 {
987 	transport_subsystem_release(&fileio_template);
988 }
989 
990 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
991 MODULE_AUTHOR("nab@Linux-iSCSI.org");
992 MODULE_LICENSE("GPL");
993 
994 module_init(fileio_module_init);
995 module_exit(fileio_module_exit);
996