1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * NVMe Over Fabrics Target File I/O commands implementation.
4  * Copyright (c) 2017-2018 Western Digital Corporation or its
5  * affiliates.
6  */
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 #include <linux/uio.h>
9 #include <linux/falloc.h>
10 #include <linux/file.h>
11 #include <linux/fs.h>
12 #include "nvmet.h"
13 
14 #define NVMET_MAX_MPOOL_BVEC		16
15 #define NVMET_MIN_MPOOL_OBJ		16
16 
17 void nvmet_file_ns_revalidate(struct nvmet_ns *ns)
18 {
19 	ns->size = i_size_read(ns->file->f_mapping->host);
20 }
21 
22 void nvmet_file_ns_disable(struct nvmet_ns *ns)
23 {
24 	if (ns->file) {
25 		if (ns->buffered_io)
26 			flush_workqueue(buffered_io_wq);
27 		mempool_destroy(ns->bvec_pool);
28 		ns->bvec_pool = NULL;
29 		kmem_cache_destroy(ns->bvec_cache);
30 		ns->bvec_cache = NULL;
31 		fput(ns->file);
32 		ns->file = NULL;
33 	}
34 }
35 
36 int nvmet_file_ns_enable(struct nvmet_ns *ns)
37 {
38 	int flags = O_RDWR | O_LARGEFILE;
39 	int ret = 0;
40 
41 	if (!ns->buffered_io)
42 		flags |= O_DIRECT;
43 
44 	ns->file = filp_open(ns->device_path, flags, 0);
45 	if (IS_ERR(ns->file)) {
46 		ret = PTR_ERR(ns->file);
47 		pr_err("failed to open file %s: (%d)\n",
48 			ns->device_path, ret);
49 		ns->file = NULL;
50 		return ret;
51 	}
52 
53 	nvmet_file_ns_revalidate(ns);
54 
55 	/*
56 	 * i_blkbits can be greater than the universally accepted upper bound,
57 	 * so make sure we export a sane namespace lba_shift.
58 	 */
59 	ns->blksize_shift = min_t(u8,
60 			file_inode(ns->file)->i_blkbits, 12);
61 
62 	ns->bvec_cache = kmem_cache_create("nvmet-bvec",
63 			NVMET_MAX_MPOOL_BVEC * sizeof(struct bio_vec),
64 			0, SLAB_HWCACHE_ALIGN, NULL);
65 	if (!ns->bvec_cache) {
66 		ret = -ENOMEM;
67 		goto err;
68 	}
69 
70 	ns->bvec_pool = mempool_create(NVMET_MIN_MPOOL_OBJ, mempool_alloc_slab,
71 			mempool_free_slab, ns->bvec_cache);
72 
73 	if (!ns->bvec_pool) {
74 		ret = -ENOMEM;
75 		goto err;
76 	}
77 
78 	return ret;
79 err:
80 	ns->size = 0;
81 	ns->blksize_shift = 0;
82 	nvmet_file_ns_disable(ns);
83 	return ret;
84 }
85 
86 static void nvmet_file_init_bvec(struct bio_vec *bv, struct scatterlist *sg)
87 {
88 	bv->bv_page = sg_page(sg);
89 	bv->bv_offset = sg->offset;
90 	bv->bv_len = sg->length;
91 }
92 
93 static ssize_t nvmet_file_submit_bvec(struct nvmet_req *req, loff_t pos,
94 		unsigned long nr_segs, size_t count, int ki_flags)
95 {
96 	struct kiocb *iocb = &req->f.iocb;
97 	ssize_t (*call_iter)(struct kiocb *iocb, struct iov_iter *iter);
98 	struct iov_iter iter;
99 	int rw;
100 
101 	if (req->cmd->rw.opcode == nvme_cmd_write) {
102 		if (req->cmd->rw.control & cpu_to_le16(NVME_RW_FUA))
103 			ki_flags |= IOCB_DSYNC;
104 		call_iter = req->ns->file->f_op->write_iter;
105 		rw = WRITE;
106 	} else {
107 		call_iter = req->ns->file->f_op->read_iter;
108 		rw = READ;
109 	}
110 
111 	iov_iter_bvec(&iter, rw, req->f.bvec, nr_segs, count);
112 
113 	iocb->ki_pos = pos;
114 	iocb->ki_filp = req->ns->file;
115 	iocb->ki_flags = ki_flags | iocb_flags(req->ns->file);
116 
117 	return call_iter(iocb, &iter);
118 }
119 
120 static void nvmet_file_io_done(struct kiocb *iocb, long ret)
121 {
122 	struct nvmet_req *req = container_of(iocb, struct nvmet_req, f.iocb);
123 	u16 status = NVME_SC_SUCCESS;
124 
125 	if (req->f.bvec != req->inline_bvec) {
126 		if (likely(req->f.mpool_alloc == false))
127 			kfree(req->f.bvec);
128 		else
129 			mempool_free(req->f.bvec, req->ns->bvec_pool);
130 	}
131 
132 	if (unlikely(ret != req->transfer_len))
133 		status = errno_to_nvme_status(req, ret);
134 	nvmet_req_complete(req, status);
135 }
136 
137 static bool nvmet_file_execute_io(struct nvmet_req *req, int ki_flags)
138 {
139 	ssize_t nr_bvec = req->sg_cnt;
140 	unsigned long bv_cnt = 0;
141 	bool is_sync = false;
142 	size_t len = 0, total_len = 0;
143 	ssize_t ret = 0;
144 	loff_t pos;
145 	int i;
146 	struct scatterlist *sg;
147 
148 	if (req->f.mpool_alloc && nr_bvec > NVMET_MAX_MPOOL_BVEC)
149 		is_sync = true;
150 
151 	pos = le64_to_cpu(req->cmd->rw.slba) << req->ns->blksize_shift;
152 	if (unlikely(pos + req->transfer_len > req->ns->size)) {
153 		nvmet_req_complete(req, errno_to_nvme_status(req, -ENOSPC));
154 		return true;
155 	}
156 
157 	memset(&req->f.iocb, 0, sizeof(struct kiocb));
158 	for_each_sg(req->sg, sg, req->sg_cnt, i) {
159 		nvmet_file_init_bvec(&req->f.bvec[bv_cnt], sg);
160 		len += req->f.bvec[bv_cnt].bv_len;
161 		total_len += req->f.bvec[bv_cnt].bv_len;
162 		bv_cnt++;
163 
164 		WARN_ON_ONCE((nr_bvec - 1) < 0);
165 
166 		if (unlikely(is_sync) &&
167 		    (nr_bvec - 1 == 0 || bv_cnt == NVMET_MAX_MPOOL_BVEC)) {
168 			ret = nvmet_file_submit_bvec(req, pos, bv_cnt, len, 0);
169 			if (ret < 0)
170 				goto complete;
171 
172 			pos += len;
173 			bv_cnt = 0;
174 			len = 0;
175 		}
176 		nr_bvec--;
177 	}
178 
179 	if (WARN_ON_ONCE(total_len != req->transfer_len)) {
180 		ret = -EIO;
181 		goto complete;
182 	}
183 
184 	if (unlikely(is_sync)) {
185 		ret = total_len;
186 		goto complete;
187 	}
188 
189 	/*
190 	 * A NULL ki_complete ask for synchronous execution, which we want
191 	 * for the IOCB_NOWAIT case.
192 	 */
193 	if (!(ki_flags & IOCB_NOWAIT))
194 		req->f.iocb.ki_complete = nvmet_file_io_done;
195 
196 	ret = nvmet_file_submit_bvec(req, pos, bv_cnt, total_len, ki_flags);
197 
198 	switch (ret) {
199 	case -EIOCBQUEUED:
200 		return true;
201 	case -EAGAIN:
202 		if (WARN_ON_ONCE(!(ki_flags & IOCB_NOWAIT)))
203 			goto complete;
204 		return false;
205 	case -EOPNOTSUPP:
206 		/*
207 		 * For file systems returning error -EOPNOTSUPP, handle
208 		 * IOCB_NOWAIT error case separately and retry without
209 		 * IOCB_NOWAIT.
210 		 */
211 		if ((ki_flags & IOCB_NOWAIT))
212 			return false;
213 		break;
214 	}
215 
216 complete:
217 	nvmet_file_io_done(&req->f.iocb, ret);
218 	return true;
219 }
220 
221 static void nvmet_file_buffered_io_work(struct work_struct *w)
222 {
223 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
224 
225 	nvmet_file_execute_io(req, 0);
226 }
227 
228 static void nvmet_file_submit_buffered_io(struct nvmet_req *req)
229 {
230 	INIT_WORK(&req->f.work, nvmet_file_buffered_io_work);
231 	queue_work(buffered_io_wq, &req->f.work);
232 }
233 
234 static void nvmet_file_execute_rw(struct nvmet_req *req)
235 {
236 	ssize_t nr_bvec = req->sg_cnt;
237 
238 	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
239 		return;
240 
241 	if (!req->sg_cnt || !nr_bvec) {
242 		nvmet_req_complete(req, 0);
243 		return;
244 	}
245 
246 	if (nr_bvec > NVMET_MAX_INLINE_BIOVEC)
247 		req->f.bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
248 				GFP_KERNEL);
249 	else
250 		req->f.bvec = req->inline_bvec;
251 
252 	if (unlikely(!req->f.bvec)) {
253 		/* fallback under memory pressure */
254 		req->f.bvec = mempool_alloc(req->ns->bvec_pool, GFP_KERNEL);
255 		req->f.mpool_alloc = true;
256 	} else
257 		req->f.mpool_alloc = false;
258 
259 	if (req->ns->buffered_io) {
260 		if (likely(!req->f.mpool_alloc) &&
261 		    (req->ns->file->f_mode & FMODE_NOWAIT) &&
262 		    nvmet_file_execute_io(req, IOCB_NOWAIT))
263 			return;
264 		nvmet_file_submit_buffered_io(req);
265 	} else
266 		nvmet_file_execute_io(req, 0);
267 }
268 
269 u16 nvmet_file_flush(struct nvmet_req *req)
270 {
271 	return errno_to_nvme_status(req, vfs_fsync(req->ns->file, 1));
272 }
273 
274 static void nvmet_file_flush_work(struct work_struct *w)
275 {
276 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
277 
278 	nvmet_req_complete(req, nvmet_file_flush(req));
279 }
280 
281 static void nvmet_file_execute_flush(struct nvmet_req *req)
282 {
283 	if (!nvmet_check_transfer_len(req, 0))
284 		return;
285 	INIT_WORK(&req->f.work, nvmet_file_flush_work);
286 	queue_work(nvmet_wq, &req->f.work);
287 }
288 
289 static void nvmet_file_execute_discard(struct nvmet_req *req)
290 {
291 	int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
292 	struct nvme_dsm_range range;
293 	loff_t offset, len;
294 	u16 status = 0;
295 	int ret;
296 	int i;
297 
298 	for (i = 0; i <= le32_to_cpu(req->cmd->dsm.nr); i++) {
299 		status = nvmet_copy_from_sgl(req, i * sizeof(range), &range,
300 					sizeof(range));
301 		if (status)
302 			break;
303 
304 		offset = le64_to_cpu(range.slba) << req->ns->blksize_shift;
305 		len = le32_to_cpu(range.nlb);
306 		len <<= req->ns->blksize_shift;
307 		if (offset + len > req->ns->size) {
308 			req->error_slba = le64_to_cpu(range.slba);
309 			status = errno_to_nvme_status(req, -ENOSPC);
310 			break;
311 		}
312 
313 		ret = vfs_fallocate(req->ns->file, mode, offset, len);
314 		if (ret && ret != -EOPNOTSUPP) {
315 			req->error_slba = le64_to_cpu(range.slba);
316 			status = errno_to_nvme_status(req, ret);
317 			break;
318 		}
319 	}
320 
321 	nvmet_req_complete(req, status);
322 }
323 
324 static void nvmet_file_dsm_work(struct work_struct *w)
325 {
326 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
327 
328 	switch (le32_to_cpu(req->cmd->dsm.attributes)) {
329 	case NVME_DSMGMT_AD:
330 		nvmet_file_execute_discard(req);
331 		return;
332 	case NVME_DSMGMT_IDR:
333 	case NVME_DSMGMT_IDW:
334 	default:
335 		/* Not supported yet */
336 		nvmet_req_complete(req, 0);
337 		return;
338 	}
339 }
340 
341 static void nvmet_file_execute_dsm(struct nvmet_req *req)
342 {
343 	if (!nvmet_check_data_len_lte(req, nvmet_dsm_len(req)))
344 		return;
345 	INIT_WORK(&req->f.work, nvmet_file_dsm_work);
346 	queue_work(nvmet_wq, &req->f.work);
347 }
348 
349 static void nvmet_file_write_zeroes_work(struct work_struct *w)
350 {
351 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
352 	struct nvme_write_zeroes_cmd *write_zeroes = &req->cmd->write_zeroes;
353 	int mode = FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE;
354 	loff_t offset;
355 	loff_t len;
356 	int ret;
357 
358 	offset = le64_to_cpu(write_zeroes->slba) << req->ns->blksize_shift;
359 	len = (((sector_t)le16_to_cpu(write_zeroes->length) + 1) <<
360 			req->ns->blksize_shift);
361 
362 	if (unlikely(offset + len > req->ns->size)) {
363 		nvmet_req_complete(req, errno_to_nvme_status(req, -ENOSPC));
364 		return;
365 	}
366 
367 	ret = vfs_fallocate(req->ns->file, mode, offset, len);
368 	nvmet_req_complete(req, ret < 0 ? errno_to_nvme_status(req, ret) : 0);
369 }
370 
371 static void nvmet_file_execute_write_zeroes(struct nvmet_req *req)
372 {
373 	if (!nvmet_check_transfer_len(req, 0))
374 		return;
375 	INIT_WORK(&req->f.work, nvmet_file_write_zeroes_work);
376 	queue_work(nvmet_wq, &req->f.work);
377 }
378 
379 u16 nvmet_file_parse_io_cmd(struct nvmet_req *req)
380 {
381 	switch (req->cmd->common.opcode) {
382 	case nvme_cmd_read:
383 	case nvme_cmd_write:
384 		req->execute = nvmet_file_execute_rw;
385 		return 0;
386 	case nvme_cmd_flush:
387 		req->execute = nvmet_file_execute_flush;
388 		return 0;
389 	case nvme_cmd_dsm:
390 		req->execute = nvmet_file_execute_dsm;
391 		return 0;
392 	case nvme_cmd_write_zeroes:
393 		req->execute = nvmet_file_execute_write_zeroes;
394 		return 0;
395 	default:
396 		return nvmet_report_invalid_opcode(req);
397 	}
398 }
399