summaryrefslogtreecommitdiffstats
path: root/fs/fuse/file.c
blob: a8dc88527fbe61421c5d199c40fa9d3254cebc73 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2001-2005  Miklos Szeredi <miklos@szeredi.hu>

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/kernel.h>

static struct file_operations fuse_direct_io_file_operations;

int fuse_open_common(struct inode *inode, struct file *file, int isdir)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_req *req;
	struct fuse_open_in inarg;
	struct fuse_open_out outarg;
	struct fuse_file *ff;
	int err;
	/* Restarting the syscall is not allowed if O_CREAT and O_EXCL
	   are both set, because creation will fail on the restart */
	int excl = (file->f_flags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL);

	err = generic_file_open(inode, file);
	if (err)
		return err;

	/* If opening the root node, no lookup has been performed on
	   it, so the attributes must be refreshed */
	if (get_node_id(inode) == FUSE_ROOT_ID) {
		int err = fuse_do_getattr(inode);
		if (err)
		 	return err;
	}

	if (excl)
		req = fuse_get_request_nonint(fc);
	else
		req = fuse_get_request(fc);
	if (!req)
		return excl ? -EINTR : -ERESTARTSYS;

	err = -ENOMEM;
	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
	if (!ff)
		goto out_put_request;

	ff->release_req = fuse_request_alloc();
	if (!ff->release_req) {
		kfree(ff);
		goto out_put_request;
	}

	memset(&inarg, 0, sizeof(inarg));
	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
	req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
	req->in.h.nodeid = get_node_id(inode);
	req->inode = inode;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(outarg);
	req->out.args[0].value = &outarg;
	if (excl)
		request_send_nonint(fc, req);
	else
		request_send(fc, req);
	err = req->out.h.error;
	if (err) {
		fuse_request_free(ff->release_req);
		kfree(ff);
	} else {
		if (!isdir && (outarg.open_flags & FOPEN_DIRECT_IO))
			file->f_op = &fuse_direct_io_file_operations;
		if (!(outarg.open_flags & FOPEN_KEEP_CACHE))
			invalidate_inode_pages(inode->i_mapping);
		ff->fh = outarg.fh;
		file->private_data = ff;
	}

 out_put_request:
	fuse_put_request(fc, req);
	return err;
}

int fuse_release_common(struct inode *inode, struct file *file, int isdir)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req = ff->release_req;
	struct fuse_release_in *inarg = &req->misc.release_in;

	inarg->fh = ff->fh;
	inarg->flags = file->f_flags & ~O_EXCL;
	req->in.h.opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
	req->in.h.nodeid = get_node_id(inode);
	req->inode = inode;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(struct fuse_release_in);
	req->in.args[0].value = inarg;
	request_send_background(fc, req);
	kfree(ff);

	/* Return value is ignored by VFS */
	return 0;
}

static int fuse_open(struct inode *inode, struct file *file)
{
	return fuse_open_common(inode, file, 0);
}

static int fuse_release(struct inode *inode, struct file *file)
{
	return fuse_release_common(inode, file, 0);
}

static int fuse_flush(struct file *file)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req;
	struct fuse_flush_in inarg;
	int err;

	if (fc->no_flush)
		return 0;

	req = fuse_get_request_nonint(fc);
	if (!req)
		return -EINTR;

	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
	req->in.h.opcode = FUSE_FLUSH;
	req->in.h.nodeid = get_node_id(inode);
	req->inode = inode;
	req->file = file;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	request_send_nonint(fc, req);
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS) {
		fc->no_flush = 1;
		err = 0;
	}
	return err;
}

static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
{
	struct inode *inode = de->d_inode;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req;
	struct fuse_fsync_in inarg;
	int err;

	if (fc->no_fsync)
		return 0;

	req = fuse_get_request(fc);
	if (!req)
		return -ERESTARTSYS;

	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
	inarg.fsync_flags = datasync ? 1 : 0;
	req->in.h.opcode = FUSE_FSYNC;
	req->in.h.nodeid = get_node_id(inode);
	req->inode = inode;
	req->file = file;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	request_send(fc, req);
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS) {
		fc->no_fsync = 1;
		err = 0;
	}
	return err;
}

size_t fuse_send_read_common(struct fuse_req *req, struct file *file,
			     struct inode *inode, loff_t pos, size_t count,
			     int isdir)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_read_in inarg;

	memset(&inarg, 0, sizeof(struct fuse_read_in));
	inarg.fh = ff->fh;
	inarg.offset = pos;
	inarg.size = count;
	req->in.h.opcode = isdir ? FUSE_READDIR : FUSE_READ;
	req->in.h.nodeid = get_node_id(inode);
	req->inode = inode;
	req->file = file;
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(struct fuse_read_in);
	req->in.args[0].value = &inarg;
	req->out.argpages = 1;
	req->out.argvar = 1;
	req->out.numargs = 1;
	req->out.args[0].size = count;
	request_send_nonint(fc, req);
	return req->out.args[0].size;
}

static inline size_t fuse_send_read(struct fuse_req *req, struct file *file,
				    struct inode *inode, loff_t pos,
				    size_t count)
{
	return fuse_send_read_common(req, file, inode, pos, count, 0);
}

static int fuse_readpage(struct file *file, struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	loff_t pos = (loff_t) page->index << PAGE_CACHE_SHIFT;
	struct fuse_req *req = fuse_get_request_nonint(fc);
	int err = -EINTR;
	if (!req)
		goto out;

	req->out.page_zeroing = 1;
	req->num_pages = 1;
	req->pages[0] = page;
	fuse_send_read(req, file, inode, pos, PAGE_CACHE_SIZE);
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (!err)
		SetPageUptodate(page);
 out:
	unlock_page(page);
	return err;
}

static int fuse_send_readpages(struct fuse_req *req, struct file *file,
			       struct inode *inode)
{
	loff_t pos = (loff_t) req->pages[0]->index << PAGE_CACHE_SHIFT;
	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
	unsigned i;
	req->out.page_zeroing = 1;
	fuse_send_read(req, file, inode, pos, count);
	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (!req->out.h.error)
			SetPageUptodate(page);
		unlock_page(page);
	}
	return req->out.h.error;
}

struct fuse_readpages_data {
	struct fuse_req *req;
	struct file *file;
	struct inode *inode;
};

static int fuse_readpages_fill(void *_data, struct page *page)
{
	struct fuse_readpages_data *data = _data;
	struct fuse_req *req = data->req;
	struct inode *inode = data->inode;
	struct fuse_conn *fc = get_fuse_conn(inode);

	if (req->num_pages &&
	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
		int err = fuse_send_readpages(req, data->file, inode);
		if (err) {
			unlock_page(page);
			return err;
		}
		fuse_reset_request(req);
	}
	req->pages[req->num_pages] = page;
	req->num_pages ++;
	return 0;
}

static int fuse_readpages(struct file *file, struct address_space *mapping,
			  struct list_head *pages, unsigned nr_pages)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_readpages_data data;
	int err;
	data.file = file;
	data.inode = inode;
	data.req = fuse_get_request_nonint(fc);
	if (!data.req)
		return -EINTR;

	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
	if (!err && data.req->num_pages)
		err = fuse_send_readpages(data.req, file, inode);
	fuse_put_request(fc, data.req);
	return err;
}

static size_t fuse_send_write(struct fuse_req *req, struct file *file,
			      struct inode *inode, loff_t pos, size_t count)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_write_in inarg;
	struct fuse_write_out outarg;

	memset(&inarg, 0, sizeof(struct fuse_write_in));
	inarg.fh = ff->fh;
	inarg.offset = pos;
	inarg.size = count;
	req->in.h.opcode = FUSE_WRITE;
	req->in.h.nodeid = get_node_id(inode);
	req->inode = inode;
	req->file = file;
	req->in.argpages = 1;
	req->in.numargs = 2;
	req->in.args[0].size = sizeof(struct fuse_write_in);
	req->in.args[0].value = &inarg;
	req->in.args[1].size = count;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(struct fuse_write_out);
	req->out.args[0].value = &outarg;
	request_send_nonint(fc, req);
	return outarg.size;
}

static int fuse_prepare_write(struct file *file, struct page *page,
			      unsigned offset, unsigned to)
{
	/* No op */
	return 0;
}

static int fuse_commit_write(struct file *file, struct page *page,
			     unsigned offset, unsigned to)
{
	int err;
	size_t nres;
	unsigned count = to - offset;
	struct inode *inode = page->mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	loff_t pos = ((loff_t) page->index << PAGE_CACHE_SHIFT) + offset;
	struct fuse_req *req = fuse_get_request_nonint(fc);
	if (!req)
		return -EINTR;

	req->num_pages = 1;
	req->pages[0] = page;
	req->page_offset = offset;
	nres = fuse_send_write(req, file, inode, pos, count);
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (!err && nres != count)
		err = -EIO;
	if (!err) {
		pos += count;
		if (pos > i_size_read(inode))
			i_size_write(inode, pos);

		if (offset == 0 && to == PAGE_CACHE_SIZE) {
			clear_page_dirty(page);
			SetPageUptodate(page);
		}
	} else if (err == -EINTR || err == -EIO)
		fuse_invalidate_attr(inode);
	return err;
}

static void fuse_release_user_pages(struct fuse_req *req, int write)
{
	unsigned i;

	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (write)
			set_page_dirty_lock(page);
		put_page(page);
	}
}

static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
			       unsigned nbytes, int write)
{
	unsigned long user_addr = (unsigned long) buf;
	unsigned offset = user_addr & ~PAGE_MASK;
	int npages;

	/* This doesn't work with nfsd */
	if (!current->mm)
		return -EPERM;

	nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
	npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
	npages = min(npages, FUSE_MAX_PAGES_PER_REQ);
	down_read(&current->mm->mmap_sem);
	npages = get_user_pages(current, current->mm, user_addr, npages, write,
				0, req->pages, NULL);
	up_read(&current->mm->mmap_sem);
	if (npages < 0)
		return npages;

	req->num_pages = npages;
	req->page_offset = offset;
	return 0;
}

static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
			      size_t count, loff_t *ppos, int write)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct fuse_conn *fc = get_fuse_conn(inode);
	size_t nmax = write ? fc->max_write : fc->max_read;
	loff_t pos = *ppos;
	ssize_t res = 0;
	struct fuse_req *req = fuse_get_request(fc);
	if (!req)
		return -ERESTARTSYS;

	while (count) {
		size_t tmp;
		size_t nres;
		size_t nbytes = min(count, nmax);
		int err = fuse_get_user_pages(req, buf, nbytes, !write);
		if (err) {
			res = err;
			break;
		}
		tmp = (req->num_pages << PAGE_SHIFT) - req->page_offset;
		nbytes = min(nbytes, tmp);
		if (write)
			nres = fuse_send_write(req, file, inode, pos, nbytes);
		else
			nres = fuse_send_read(req, file, inode, pos, nbytes);
		fuse_release_user_pages(req, !write);
		if (req->out.h.error) {
			if (!res)
				res = req->out.h.error;
			break;
		} else if (nres > nbytes) {
			res = -EIO;
			break;
		}
		count -= nres;
		res += nres;
		pos += nres;
		buf += nres;
		if (nres != nbytes)
			break;
		if (count)
			fuse_reset_request(req);
	}
	fuse_put_request(fc, req);
	if (res > 0) {
		if (write && pos > i_size_read(inode))
			i_size_write(inode, pos);
		*ppos = pos;
	} else if (write && (res == -EINTR || res == -EIO))
		fuse_invalidate_attr(inode);

	return res;
}

static ssize_t fuse_direct_read(struct file *file, char __user *buf,
				     size_t count, loff_t *ppos)
{
	return fuse_direct_io(file, buf, count, ppos, 0);
}

static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
				 size_t count, loff_t *ppos)
{
	struct inode *inode = file->f_dentry->d_inode;
	ssize_t res;
	/* Don't allow parallel writes to the same file */
	down(&inode->i_sem);
	res = fuse_direct_io(file, buf, count, ppos, 1);
	up(&inode->i_sem);
	return res;
}

static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
{
	if ((vma->vm_flags & VM_SHARED)) {
		if ((vma->vm_flags & VM_WRITE))
			return -ENODEV;
		else
			vma->vm_flags &= ~VM_MAYWRITE;
	}
	return generic_file_mmap(file, vma);
}

static int fuse_set_page_dirty(struct page *page)
{
	printk("fuse_set_page_dirty: should not happen\n");
	dump_stack();
	return 0;
}

static struct file_operations fuse_file_operations = {
	.llseek		= generic_file_llseek,
	.read		= generic_file_read,
	.write		= generic_file_write,
	.mmap		= fuse_file_mmap,
	.open		= fuse_open,
	.flush		= fuse_flush,
	.release	= fuse_release,
	.fsync		= fuse_fsync,
	.sendfile	= generic_file_sendfile,
};

static struct file_operations fuse_direct_io_file_operations = {
	.llseek		= generic_file_llseek,
	.read		= fuse_direct_read,
	.write		= fuse_direct_write,
	.open		= fuse_open,
	.flush		= fuse_flush,
	.release	= fuse_release,
	.fsync		= fuse_fsync,
	/* no mmap and sendfile */
};

static struct address_space_operations fuse_file_aops  = {
	.readpage	= fuse_readpage,
	.prepare_write	= fuse_prepare_write,
	.commit_write	= fuse_commit_write,
	.readpages	= fuse_readpages,
	.set_page_dirty	= fuse_set_page_dirty,
};

void fuse_init_file_inode(struct inode *inode)
{
	inode->i_fop = &fuse_file_operations;
	inode->i_data.a_ops = &fuse_file_aops;
}
OpenPOWER on IntegriCloud