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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 
nvmet_file_ns_revalidate(struct nvmet_ns * ns)17 int nvmet_file_ns_revalidate(struct nvmet_ns *ns)
18 {
19 	struct kstat stat;
20 	int ret;
21 
22 	ret = vfs_getattr(&ns->file->f_path, &stat, STATX_SIZE,
23 			  AT_STATX_FORCE_SYNC);
24 	if (!ret)
25 		ns->size = stat.size;
26 	return ret;
27 }
28 
nvmet_file_ns_disable(struct nvmet_ns * ns)29 void nvmet_file_ns_disable(struct nvmet_ns *ns)
30 {
31 	if (ns->file) {
32 		if (ns->buffered_io)
33 			flush_workqueue(buffered_io_wq);
34 		mempool_destroy(ns->bvec_pool);
35 		ns->bvec_pool = NULL;
36 		kmem_cache_destroy(ns->bvec_cache);
37 		ns->bvec_cache = NULL;
38 		fput(ns->file);
39 		ns->file = NULL;
40 	}
41 }
42 
nvmet_file_ns_enable(struct nvmet_ns * ns)43 int nvmet_file_ns_enable(struct nvmet_ns *ns)
44 {
45 	int flags = O_RDWR | O_LARGEFILE;
46 	int ret;
47 
48 	if (!ns->buffered_io)
49 		flags |= O_DIRECT;
50 
51 	ns->file = filp_open(ns->device_path, flags, 0);
52 	if (IS_ERR(ns->file)) {
53 		ret = PTR_ERR(ns->file);
54 		pr_err("failed to open file %s: (%d)\n",
55 			ns->device_path, ret);
56 		ns->file = NULL;
57 		return ret;
58 	}
59 
60 	ret = nvmet_file_ns_revalidate(ns);
61 	if (ret)
62 		goto err;
63 
64 	/*
65 	 * i_blkbits can be greater than the universally accepted upper bound,
66 	 * so make sure we export a sane namespace lba_shift.
67 	 */
68 	ns->blksize_shift = min_t(u8,
69 			file_inode(ns->file)->i_blkbits, 12);
70 
71 	ns->bvec_cache = kmem_cache_create("nvmet-bvec",
72 			NVMET_MAX_MPOOL_BVEC * sizeof(struct bio_vec),
73 			0, SLAB_HWCACHE_ALIGN, NULL);
74 	if (!ns->bvec_cache) {
75 		ret = -ENOMEM;
76 		goto err;
77 	}
78 
79 	ns->bvec_pool = mempool_create(NVMET_MIN_MPOOL_OBJ, mempool_alloc_slab,
80 			mempool_free_slab, ns->bvec_cache);
81 
82 	if (!ns->bvec_pool) {
83 		ret = -ENOMEM;
84 		goto err;
85 	}
86 
87 	return ret;
88 err:
89 	ns->size = 0;
90 	ns->blksize_shift = 0;
91 	nvmet_file_ns_disable(ns);
92 	return ret;
93 }
94 
nvmet_file_init_bvec(struct bio_vec * bv,struct scatterlist * sg)95 static void nvmet_file_init_bvec(struct bio_vec *bv, struct scatterlist *sg)
96 {
97 	bv->bv_page = sg_page(sg);
98 	bv->bv_offset = sg->offset;
99 	bv->bv_len = sg->length;
100 }
101 
nvmet_file_submit_bvec(struct nvmet_req * req,loff_t pos,unsigned long nr_segs,size_t count,int ki_flags)102 static ssize_t nvmet_file_submit_bvec(struct nvmet_req *req, loff_t pos,
103 		unsigned long nr_segs, size_t count, int ki_flags)
104 {
105 	struct kiocb *iocb = &req->f.iocb;
106 	ssize_t (*call_iter)(struct kiocb *iocb, struct iov_iter *iter);
107 	struct iov_iter iter;
108 	int rw;
109 
110 	if (req->cmd->rw.opcode == nvme_cmd_write) {
111 		if (req->cmd->rw.control & cpu_to_le16(NVME_RW_FUA))
112 			ki_flags |= IOCB_DSYNC;
113 		call_iter = req->ns->file->f_op->write_iter;
114 		rw = WRITE;
115 	} else {
116 		call_iter = req->ns->file->f_op->read_iter;
117 		rw = READ;
118 	}
119 
120 	iov_iter_bvec(&iter, rw, req->f.bvec, nr_segs, count);
121 
122 	iocb->ki_pos = pos;
123 	iocb->ki_filp = req->ns->file;
124 	iocb->ki_flags = ki_flags | iocb_flags(req->ns->file);
125 
126 	return call_iter(iocb, &iter);
127 }
128 
nvmet_file_io_done(struct kiocb * iocb,long ret,long ret2)129 static void nvmet_file_io_done(struct kiocb *iocb, long ret, long ret2)
130 {
131 	struct nvmet_req *req = container_of(iocb, struct nvmet_req, f.iocb);
132 	u16 status = NVME_SC_SUCCESS;
133 
134 	if (req->f.bvec != req->inline_bvec) {
135 		if (likely(req->f.mpool_alloc == false))
136 			kfree(req->f.bvec);
137 		else
138 			mempool_free(req->f.bvec, req->ns->bvec_pool);
139 	}
140 
141 	if (unlikely(ret != req->transfer_len))
142 		status = errno_to_nvme_status(req, ret);
143 	nvmet_req_complete(req, status);
144 }
145 
nvmet_file_execute_io(struct nvmet_req * req,int ki_flags)146 static bool nvmet_file_execute_io(struct nvmet_req *req, int ki_flags)
147 {
148 	ssize_t nr_bvec = req->sg_cnt;
149 	unsigned long bv_cnt = 0;
150 	bool is_sync = false;
151 	size_t len = 0, total_len = 0;
152 	ssize_t ret = 0;
153 	loff_t pos;
154 	int i;
155 	struct scatterlist *sg;
156 
157 	if (req->f.mpool_alloc && nr_bvec > NVMET_MAX_MPOOL_BVEC)
158 		is_sync = true;
159 
160 	pos = le64_to_cpu(req->cmd->rw.slba) << req->ns->blksize_shift;
161 	if (unlikely(pos + req->transfer_len > req->ns->size)) {
162 		nvmet_req_complete(req, errno_to_nvme_status(req, -ENOSPC));
163 		return true;
164 	}
165 
166 	memset(&req->f.iocb, 0, sizeof(struct kiocb));
167 	for_each_sg(req->sg, sg, req->sg_cnt, i) {
168 		nvmet_file_init_bvec(&req->f.bvec[bv_cnt], sg);
169 		len += req->f.bvec[bv_cnt].bv_len;
170 		total_len += req->f.bvec[bv_cnt].bv_len;
171 		bv_cnt++;
172 
173 		WARN_ON_ONCE((nr_bvec - 1) < 0);
174 
175 		if (unlikely(is_sync) &&
176 		    (nr_bvec - 1 == 0 || bv_cnt == NVMET_MAX_MPOOL_BVEC)) {
177 			ret = nvmet_file_submit_bvec(req, pos, bv_cnt, len, 0);
178 			if (ret < 0)
179 				goto complete;
180 
181 			pos += len;
182 			bv_cnt = 0;
183 			len = 0;
184 		}
185 		nr_bvec--;
186 	}
187 
188 	if (WARN_ON_ONCE(total_len != req->transfer_len)) {
189 		ret = -EIO;
190 		goto complete;
191 	}
192 
193 	if (unlikely(is_sync)) {
194 		ret = total_len;
195 		goto complete;
196 	}
197 
198 	/*
199 	 * A NULL ki_complete ask for synchronous execution, which we want
200 	 * for the IOCB_NOWAIT case.
201 	 */
202 	if (!(ki_flags & IOCB_NOWAIT))
203 		req->f.iocb.ki_complete = nvmet_file_io_done;
204 
205 	ret = nvmet_file_submit_bvec(req, pos, bv_cnt, total_len, ki_flags);
206 
207 	switch (ret) {
208 	case -EIOCBQUEUED:
209 		return true;
210 	case -EAGAIN:
211 		if (WARN_ON_ONCE(!(ki_flags & IOCB_NOWAIT)))
212 			goto complete;
213 		return false;
214 	case -EOPNOTSUPP:
215 		/*
216 		 * For file systems returning error -EOPNOTSUPP, handle
217 		 * IOCB_NOWAIT error case separately and retry without
218 		 * IOCB_NOWAIT.
219 		 */
220 		if ((ki_flags & IOCB_NOWAIT))
221 			return false;
222 		break;
223 	}
224 
225 complete:
226 	nvmet_file_io_done(&req->f.iocb, ret, 0);
227 	return true;
228 }
229 
nvmet_file_buffered_io_work(struct work_struct * w)230 static void nvmet_file_buffered_io_work(struct work_struct *w)
231 {
232 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
233 
234 	nvmet_file_execute_io(req, 0);
235 }
236 
nvmet_file_submit_buffered_io(struct nvmet_req * req)237 static void nvmet_file_submit_buffered_io(struct nvmet_req *req)
238 {
239 	INIT_WORK(&req->f.work, nvmet_file_buffered_io_work);
240 	queue_work(buffered_io_wq, &req->f.work);
241 }
242 
nvmet_file_execute_rw(struct nvmet_req * req)243 static void nvmet_file_execute_rw(struct nvmet_req *req)
244 {
245 	ssize_t nr_bvec = req->sg_cnt;
246 
247 	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
248 		return;
249 
250 	if (!req->sg_cnt || !nr_bvec) {
251 		nvmet_req_complete(req, 0);
252 		return;
253 	}
254 
255 	if (nr_bvec > NVMET_MAX_INLINE_BIOVEC)
256 		req->f.bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
257 				GFP_KERNEL);
258 	else
259 		req->f.bvec = req->inline_bvec;
260 
261 	if (unlikely(!req->f.bvec)) {
262 		/* fallback under memory pressure */
263 		req->f.bvec = mempool_alloc(req->ns->bvec_pool, GFP_KERNEL);
264 		req->f.mpool_alloc = true;
265 	} else
266 		req->f.mpool_alloc = false;
267 
268 	if (req->ns->buffered_io) {
269 		if (likely(!req->f.mpool_alloc) &&
270 		    (req->ns->file->f_mode & FMODE_NOWAIT) &&
271 		    nvmet_file_execute_io(req, IOCB_NOWAIT))
272 			return;
273 		nvmet_file_submit_buffered_io(req);
274 	} else
275 		nvmet_file_execute_io(req, 0);
276 }
277 
nvmet_file_flush(struct nvmet_req * req)278 u16 nvmet_file_flush(struct nvmet_req *req)
279 {
280 	return errno_to_nvme_status(req, vfs_fsync(req->ns->file, 1));
281 }
282 
nvmet_file_flush_work(struct work_struct * w)283 static void nvmet_file_flush_work(struct work_struct *w)
284 {
285 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
286 
287 	nvmet_req_complete(req, nvmet_file_flush(req));
288 }
289 
nvmet_file_execute_flush(struct nvmet_req * req)290 static void nvmet_file_execute_flush(struct nvmet_req *req)
291 {
292 	if (!nvmet_check_transfer_len(req, 0))
293 		return;
294 	INIT_WORK(&req->f.work, nvmet_file_flush_work);
295 	schedule_work(&req->f.work);
296 }
297 
nvmet_file_execute_discard(struct nvmet_req * req)298 static void nvmet_file_execute_discard(struct nvmet_req *req)
299 {
300 	int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
301 	struct nvme_dsm_range range;
302 	loff_t offset, len;
303 	u16 status = 0;
304 	int ret;
305 	int i;
306 
307 	for (i = 0; i <= le32_to_cpu(req->cmd->dsm.nr); i++) {
308 		status = nvmet_copy_from_sgl(req, i * sizeof(range), &range,
309 					sizeof(range));
310 		if (status)
311 			break;
312 
313 		offset = le64_to_cpu(range.slba) << req->ns->blksize_shift;
314 		len = le32_to_cpu(range.nlb);
315 		len <<= req->ns->blksize_shift;
316 		if (offset + len > req->ns->size) {
317 			req->error_slba = le64_to_cpu(range.slba);
318 			status = errno_to_nvme_status(req, -ENOSPC);
319 			break;
320 		}
321 
322 		ret = vfs_fallocate(req->ns->file, mode, offset, len);
323 		if (ret && ret != -EOPNOTSUPP) {
324 			req->error_slba = le64_to_cpu(range.slba);
325 			status = errno_to_nvme_status(req, ret);
326 			break;
327 		}
328 	}
329 
330 	nvmet_req_complete(req, status);
331 }
332 
nvmet_file_dsm_work(struct work_struct * w)333 static void nvmet_file_dsm_work(struct work_struct *w)
334 {
335 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
336 
337 	switch (le32_to_cpu(req->cmd->dsm.attributes)) {
338 	case NVME_DSMGMT_AD:
339 		nvmet_file_execute_discard(req);
340 		return;
341 	case NVME_DSMGMT_IDR:
342 	case NVME_DSMGMT_IDW:
343 	default:
344 		/* Not supported yet */
345 		nvmet_req_complete(req, 0);
346 		return;
347 	}
348 }
349 
nvmet_file_execute_dsm(struct nvmet_req * req)350 static void nvmet_file_execute_dsm(struct nvmet_req *req)
351 {
352 	if (!nvmet_check_data_len_lte(req, nvmet_dsm_len(req)))
353 		return;
354 	INIT_WORK(&req->f.work, nvmet_file_dsm_work);
355 	schedule_work(&req->f.work);
356 }
357 
nvmet_file_write_zeroes_work(struct work_struct * w)358 static void nvmet_file_write_zeroes_work(struct work_struct *w)
359 {
360 	struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
361 	struct nvme_write_zeroes_cmd *write_zeroes = &req->cmd->write_zeroes;
362 	int mode = FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE;
363 	loff_t offset;
364 	loff_t len;
365 	int ret;
366 
367 	offset = le64_to_cpu(write_zeroes->slba) << req->ns->blksize_shift;
368 	len = (((sector_t)le16_to_cpu(write_zeroes->length) + 1) <<
369 			req->ns->blksize_shift);
370 
371 	if (unlikely(offset + len > req->ns->size)) {
372 		nvmet_req_complete(req, errno_to_nvme_status(req, -ENOSPC));
373 		return;
374 	}
375 
376 	ret = vfs_fallocate(req->ns->file, mode, offset, len);
377 	nvmet_req_complete(req, ret < 0 ? errno_to_nvme_status(req, ret) : 0);
378 }
379 
nvmet_file_execute_write_zeroes(struct nvmet_req * req)380 static void nvmet_file_execute_write_zeroes(struct nvmet_req *req)
381 {
382 	if (!nvmet_check_transfer_len(req, 0))
383 		return;
384 	INIT_WORK(&req->f.work, nvmet_file_write_zeroes_work);
385 	schedule_work(&req->f.work);
386 }
387 
nvmet_file_parse_io_cmd(struct nvmet_req * req)388 u16 nvmet_file_parse_io_cmd(struct nvmet_req *req)
389 {
390 	struct nvme_command *cmd = req->cmd;
391 
392 	switch (cmd->common.opcode) {
393 	case nvme_cmd_read:
394 	case nvme_cmd_write:
395 		req->execute = nvmet_file_execute_rw;
396 		return 0;
397 	case nvme_cmd_flush:
398 		req->execute = nvmet_file_execute_flush;
399 		return 0;
400 	case nvme_cmd_dsm:
401 		req->execute = nvmet_file_execute_dsm;
402 		return 0;
403 	case nvme_cmd_write_zeroes:
404 		req->execute = nvmet_file_execute_write_zeroes;
405 		return 0;
406 	default:
407 		pr_err("unhandled cmd for file ns %d on qid %d\n",
408 				cmd->common.opcode, req->sq->qid);
409 		req->error_loc = offsetof(struct nvme_common_command, opcode);
410 		return NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
411 	}
412 }
413