xref: /linux/fs/afs/file.c (revision aec2f682d47c54ef434b2d440992626d80b1ebdc) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* AFS filesystem file handling
3  *
4  * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/fs.h>
12 #include <linux/pagemap.h>
13 #include <linux/writeback.h>
14 #include <linux/gfp.h>
15 #include <linux/task_io_accounting_ops.h>
16 #include <linux/mm.h>
17 #include <linux/swap.h>
18 #include <linux/netfs.h>
19 #include <trace/events/netfs.h>
20 #include "internal.h"
21 
22 static int afs_file_mmap_prepare(struct vm_area_desc *desc);
23 
24 static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
25 static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
26 				    struct pipe_inode_info *pipe,
27 				    size_t len, unsigned int flags);
28 static void afs_vm_open(struct vm_area_struct *area);
29 static void afs_vm_close(struct vm_area_struct *area);
30 static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff);
31 static int afs_mapped(unsigned long start, unsigned long end, pgoff_t pgoff,
32 		      const struct file *file, void **vm_private_data);
33 
34 const struct file_operations afs_file_operations = {
35 	.open		= afs_open,
36 	.release	= afs_release,
37 	.llseek		= generic_file_llseek,
38 	.read_iter	= afs_file_read_iter,
39 	.write_iter	= netfs_file_write_iter,
40 	.mmap_prepare	= afs_file_mmap_prepare,
41 	.splice_read	= afs_file_splice_read,
42 	.splice_write	= iter_file_splice_write,
43 	.fsync		= afs_fsync,
44 	.lock		= afs_lock,
45 	.flock		= afs_flock,
46 };
47 
48 const struct inode_operations afs_file_inode_operations = {
49 	.getattr	= afs_getattr,
50 	.setattr	= afs_setattr,
51 	.permission	= afs_permission,
52 };
53 
54 const struct address_space_operations afs_file_aops = {
55 	.direct_IO	= noop_direct_IO,
56 	.read_folio	= netfs_read_folio,
57 	.readahead	= netfs_readahead,
58 	.dirty_folio	= netfs_dirty_folio,
59 	.release_folio	= netfs_release_folio,
60 	.invalidate_folio = netfs_invalidate_folio,
61 	.migrate_folio	= filemap_migrate_folio,
62 	.writepages	= afs_writepages,
63 };
64 
65 static const struct vm_operations_struct afs_vm_ops = {
66 	.mapped		= afs_mapped,
67 	.open		= afs_vm_open,
68 	.close		= afs_vm_close,
69 	.fault		= filemap_fault,
70 	.map_pages	= afs_vm_map_pages,
71 	.page_mkwrite	= afs_page_mkwrite,
72 };
73 
74 /*
75  * Discard a pin on a writeback key.
76  */
77 void afs_put_wb_key(struct afs_wb_key *wbk)
78 {
79 	if (wbk && refcount_dec_and_test(&wbk->usage)) {
80 		key_put(wbk->key);
81 		kfree(wbk);
82 	}
83 }
84 
85 /*
86  * Cache key for writeback.
87  */
88 int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
89 {
90 	struct afs_wb_key *wbk, *p;
91 
92 	wbk = kzalloc_obj(struct afs_wb_key);
93 	if (!wbk)
94 		return -ENOMEM;
95 	refcount_set(&wbk->usage, 2);
96 	wbk->key = af->key;
97 
98 	spin_lock(&vnode->wb_lock);
99 	list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
100 		if (p->key == wbk->key)
101 			goto found;
102 	}
103 
104 	key_get(wbk->key);
105 	list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
106 	spin_unlock(&vnode->wb_lock);
107 	af->wb = wbk;
108 	return 0;
109 
110 found:
111 	refcount_inc(&p->usage);
112 	spin_unlock(&vnode->wb_lock);
113 	af->wb = p;
114 	kfree(wbk);
115 	return 0;
116 }
117 
118 /*
119  * open an AFS file or directory and attach a key to it
120  */
121 int afs_open(struct inode *inode, struct file *file)
122 {
123 	struct afs_vnode *vnode = AFS_FS_I(inode);
124 	struct afs_file *af;
125 	struct key *key;
126 	int ret;
127 
128 	_enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
129 
130 	key = afs_request_key(vnode->volume->cell);
131 	if (IS_ERR(key)) {
132 		ret = PTR_ERR(key);
133 		goto error;
134 	}
135 
136 	af = kzalloc_obj(*af);
137 	if (!af) {
138 		ret = -ENOMEM;
139 		goto error_key;
140 	}
141 	af->key = key;
142 
143 	ret = afs_validate(vnode, key);
144 	if (ret < 0)
145 		goto error_af;
146 
147 	if (file->f_mode & FMODE_WRITE) {
148 		ret = afs_cache_wb_key(vnode, af);
149 		if (ret < 0)
150 			goto error_af;
151 	}
152 
153 	if (file->f_flags & O_TRUNC)
154 		set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
155 
156 	fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
157 
158 	file->private_data = af;
159 	_leave(" = 0");
160 	return 0;
161 
162 error_af:
163 	kfree(af);
164 error_key:
165 	key_put(key);
166 error:
167 	_leave(" = %d", ret);
168 	return ret;
169 }
170 
171 /*
172  * release an AFS file or directory and discard its key
173  */
174 int afs_release(struct inode *inode, struct file *file)
175 {
176 	struct afs_vnode_cache_aux aux;
177 	struct afs_vnode *vnode = AFS_FS_I(inode);
178 	struct afs_file *af = file->private_data;
179 	loff_t i_size;
180 	int ret = 0;
181 
182 	_enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
183 
184 	if ((file->f_mode & FMODE_WRITE))
185 		ret = vfs_fsync(file, 0);
186 
187 	file->private_data = NULL;
188 	if (af->wb)
189 		afs_put_wb_key(af->wb);
190 
191 	if ((file->f_mode & FMODE_WRITE)) {
192 		i_size = i_size_read(&vnode->netfs.inode);
193 		afs_set_cache_aux(vnode, &aux);
194 		fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
195 	} else {
196 		fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
197 	}
198 
199 	key_put(af->key);
200 	kfree(af);
201 	afs_prune_wb_keys(vnode);
202 	_leave(" = %d", ret);
203 	return ret;
204 }
205 
206 static void afs_fetch_data_notify(struct afs_operation *op)
207 {
208 	struct netfs_io_subrequest *subreq = op->fetch.subreq;
209 
210 	subreq->error = afs_op_error(op);
211 	netfs_read_subreq_terminated(subreq);
212 }
213 
214 static void afs_fetch_data_success(struct afs_operation *op)
215 {
216 	struct afs_vnode *vnode = op->file[0].vnode;
217 
218 	_enter("op=%08x", op->debug_id);
219 	afs_vnode_commit_status(op, &op->file[0]);
220 	afs_stat_v(vnode, n_fetches);
221 	atomic_long_add(op->fetch.subreq->transferred, &op->net->n_fetch_bytes);
222 	afs_fetch_data_notify(op);
223 }
224 
225 static void afs_fetch_data_aborted(struct afs_operation *op)
226 {
227 	afs_check_for_remote_deletion(op);
228 	afs_fetch_data_notify(op);
229 }
230 
231 const struct afs_operation_ops afs_fetch_data_operation = {
232 	.issue_afs_rpc	= afs_fs_fetch_data,
233 	.issue_yfs_rpc	= yfs_fs_fetch_data,
234 	.success	= afs_fetch_data_success,
235 	.aborted	= afs_fetch_data_aborted,
236 	.failed		= afs_fetch_data_notify,
237 };
238 
239 static void afs_issue_read_call(struct afs_operation *op)
240 {
241 	op->call_responded = false;
242 	op->call_error = 0;
243 	op->call_abort_code = 0;
244 	if (test_bit(AFS_SERVER_FL_IS_YFS, &op->server->flags))
245 		yfs_fs_fetch_data(op);
246 	else
247 		afs_fs_fetch_data(op);
248 }
249 
250 static void afs_end_read(struct afs_operation *op)
251 {
252 	if (op->call_responded && op->server)
253 		set_bit(AFS_SERVER_FL_RESPONDING, &op->server->flags);
254 
255 	if (!afs_op_error(op))
256 		afs_fetch_data_success(op);
257 	else if (op->cumul_error.aborted)
258 		afs_fetch_data_aborted(op);
259 	else
260 		afs_fetch_data_notify(op);
261 
262 	afs_end_vnode_operation(op);
263 	afs_put_operation(op);
264 }
265 
266 /*
267  * Perform I/O processing on an asynchronous call.  The work item carries a ref
268  * to the call struct that we either need to release or to pass on.
269  */
270 static void afs_read_receive(struct afs_call *call)
271 {
272 	struct afs_operation *op = call->op;
273 	enum afs_call_state state;
274 
275 	_enter("");
276 
277 	state = READ_ONCE(call->state);
278 	if (state == AFS_CALL_COMPLETE)
279 		return;
280 	trace_afs_read_recv(op, call);
281 
282 	while (state < AFS_CALL_COMPLETE && READ_ONCE(call->need_attention)) {
283 		WRITE_ONCE(call->need_attention, false);
284 		afs_deliver_to_call(call);
285 		state = READ_ONCE(call->state);
286 	}
287 
288 	if (state < AFS_CALL_COMPLETE) {
289 		netfs_read_subreq_progress(op->fetch.subreq);
290 		if (rxrpc_kernel_check_life(call->net->socket, call->rxcall))
291 			return;
292 		/* rxrpc terminated the call. */
293 		afs_set_call_complete(call, call->error, call->abort_code);
294 	}
295 
296 	op->call_abort_code	= call->abort_code;
297 	op->call_error		= call->error;
298 	op->call_responded	= call->responded;
299 	op->call		= NULL;
300 	call->op		= NULL;
301 	afs_put_call(call);
302 
303 	/* If the call failed, then we need to crank the server rotation
304 	 * handle and try the next.
305 	 */
306 	if (afs_select_fileserver(op)) {
307 		afs_issue_read_call(op);
308 		return;
309 	}
310 
311 	afs_end_read(op);
312 }
313 
314 void afs_fetch_data_async_rx(struct work_struct *work)
315 {
316 	struct afs_call *call = container_of(work, struct afs_call, async_work);
317 
318 	afs_read_receive(call);
319 	afs_put_call(call);
320 }
321 
322 void afs_fetch_data_immediate_cancel(struct afs_call *call)
323 {
324 	if (call->async) {
325 		afs_get_call(call, afs_call_trace_wake);
326 		if (!queue_work(afs_async_calls, &call->async_work))
327 			afs_deferred_put_call(call);
328 		flush_work(&call->async_work);
329 	}
330 }
331 
332 /*
333  * Fetch file data from the volume.
334  */
335 static void afs_issue_read(struct netfs_io_subrequest *subreq)
336 {
337 	struct afs_operation *op;
338 	struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
339 	struct key *key = subreq->rreq->netfs_priv;
340 
341 	_enter("%s{%llx:%llu.%u},%x,,,",
342 	       vnode->volume->name,
343 	       vnode->fid.vid,
344 	       vnode->fid.vnode,
345 	       vnode->fid.unique,
346 	       key_serial(key));
347 
348 	op = afs_alloc_operation(key, vnode->volume);
349 	if (IS_ERR(op)) {
350 		subreq->error = PTR_ERR(op);
351 		netfs_read_subreq_terminated(subreq);
352 		return;
353 	}
354 
355 	afs_op_set_vnode(op, 0, vnode);
356 
357 	op->fetch.subreq = subreq;
358 	op->ops		= &afs_fetch_data_operation;
359 
360 	trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
361 
362 	if (subreq->rreq->origin == NETFS_READAHEAD ||
363 	    subreq->rreq->iocb) {
364 		op->flags |= AFS_OPERATION_ASYNC;
365 
366 		if (!afs_begin_vnode_operation(op)) {
367 			subreq->error = afs_put_operation(op);
368 			netfs_read_subreq_terminated(subreq);
369 			return;
370 		}
371 
372 		if (!afs_select_fileserver(op)) {
373 			afs_end_read(op);
374 			return;
375 		}
376 
377 		afs_issue_read_call(op);
378 	} else {
379 		afs_do_sync_operation(op);
380 	}
381 }
382 
383 static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
384 {
385 	struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
386 
387 	if (file)
388 		rreq->netfs_priv = key_get(afs_file_key(file));
389 	rreq->rsize = 256 * 1024;
390 	rreq->wsize = 256 * 1024 * 1024;
391 
392 	switch (rreq->origin) {
393 	case NETFS_READ_SINGLE:
394 		if (!file) {
395 			struct key *key = afs_request_key(vnode->volume->cell);
396 
397 			if (IS_ERR(key))
398 				return PTR_ERR(key);
399 			rreq->netfs_priv = key;
400 		}
401 		break;
402 	case NETFS_WRITEBACK:
403 	case NETFS_WRITETHROUGH:
404 	case NETFS_UNBUFFERED_WRITE:
405 	case NETFS_DIO_WRITE:
406 		if (S_ISREG(rreq->inode->i_mode))
407 			rreq->io_streams[0].avail = true;
408 		break;
409 	case NETFS_WRITEBACK_SINGLE:
410 	default:
411 		break;
412 	}
413 	return 0;
414 }
415 
416 static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
417 				 struct folio **foliop, void **_fsdata)
418 {
419 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
420 
421 	return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
422 }
423 
424 static void afs_free_request(struct netfs_io_request *rreq)
425 {
426 	key_put(rreq->netfs_priv);
427 	afs_put_wb_key(rreq->netfs_priv2);
428 }
429 
430 static void afs_update_i_size(struct inode *inode, loff_t new_i_size)
431 {
432 	struct afs_vnode *vnode = AFS_FS_I(inode);
433 	loff_t i_size;
434 
435 	write_seqlock(&vnode->cb_lock);
436 	i_size = i_size_read(&vnode->netfs.inode);
437 	if (new_i_size > i_size) {
438 		i_size_write(&vnode->netfs.inode, new_i_size);
439 		inode_set_bytes(&vnode->netfs.inode, new_i_size);
440 	}
441 	write_sequnlock(&vnode->cb_lock);
442 	fscache_update_cookie(afs_vnode_cache(vnode), NULL, &new_i_size);
443 }
444 
445 static void afs_netfs_invalidate_cache(struct netfs_io_request *wreq)
446 {
447 	struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
448 
449 	afs_invalidate_cache(vnode, 0);
450 }
451 
452 const struct netfs_request_ops afs_req_ops = {
453 	.init_request		= afs_init_request,
454 	.free_request		= afs_free_request,
455 	.check_write_begin	= afs_check_write_begin,
456 	.issue_read		= afs_issue_read,
457 	.update_i_size		= afs_update_i_size,
458 	.invalidate_cache	= afs_netfs_invalidate_cache,
459 	.begin_writeback	= afs_begin_writeback,
460 	.prepare_write		= afs_prepare_write,
461 	.issue_write		= afs_issue_write,
462 	.retry_request		= afs_retry_request,
463 };
464 
465 static void afs_add_open_mmap(struct afs_vnode *vnode)
466 {
467 	if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
468 		down_write(&vnode->volume->open_mmaps_lock);
469 
470 		if (list_empty(&vnode->cb_mmap_link))
471 			list_add_tail(&vnode->cb_mmap_link, &vnode->volume->open_mmaps);
472 
473 		up_write(&vnode->volume->open_mmaps_lock);
474 	}
475 }
476 
477 static void afs_drop_open_mmap(struct afs_vnode *vnode)
478 {
479 	if (atomic_add_unless(&vnode->cb_nr_mmap, -1, 1))
480 		return;
481 
482 	down_write(&vnode->volume->open_mmaps_lock);
483 
484 	read_seqlock_excl(&vnode->cb_lock);
485 	// the only place where ->cb_nr_mmap may hit 0
486 	// see __afs_break_callback() for the other side...
487 	if (atomic_dec_and_test(&vnode->cb_nr_mmap))
488 		list_del_init(&vnode->cb_mmap_link);
489 	read_sequnlock_excl(&vnode->cb_lock);
490 
491 	up_write(&vnode->volume->open_mmaps_lock);
492 	flush_work(&vnode->cb_work);
493 }
494 
495 /*
496  * Handle setting up a memory mapping on an AFS file.
497  */
498 static int afs_file_mmap_prepare(struct vm_area_desc *desc)
499 {
500 	int ret;
501 
502 	ret = generic_file_mmap_prepare(desc);
503 	if (ret)
504 		return ret;
505 
506 	desc->vm_ops = &afs_vm_ops;
507 	return ret;
508 }
509 
510 static int afs_mapped(unsigned long start, unsigned long end, pgoff_t pgoff,
511 		      const struct file *file, void **vm_private_data)
512 {
513 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
514 
515 	afs_add_open_mmap(vnode);
516 	return 0;
517 }
518 
519 static void afs_vm_open(struct vm_area_struct *vma)
520 {
521 	struct file *file = vma->vm_file;
522 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
523 
524 	afs_add_open_mmap(vnode);
525 }
526 
527 static void afs_vm_close(struct vm_area_struct *vma)
528 {
529 	struct file *file = vma->vm_file;
530 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
531 
532 	afs_drop_open_mmap(vnode);
533 }
534 
535 static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
536 {
537 	struct file *file = vmf->vma->vm_file;
538 	struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
539 
540 	if (afs_check_validity(vnode))
541 		return filemap_map_pages(vmf, start_pgoff, end_pgoff);
542 	return 0;
543 }
544 
545 static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
546 {
547 	struct inode *inode = file_inode(iocb->ki_filp);
548 	struct afs_vnode *vnode = AFS_FS_I(inode);
549 	struct afs_file *af = iocb->ki_filp->private_data;
550 	ssize_t ret;
551 
552 	if (iocb->ki_flags & IOCB_DIRECT)
553 		return netfs_unbuffered_read_iter(iocb, iter);
554 
555 	ret = netfs_start_io_read(inode);
556 	if (ret < 0)
557 		return ret;
558 	ret = afs_validate(vnode, af->key);
559 	if (ret == 0)
560 		ret = filemap_read(iocb, iter, 0);
561 	netfs_end_io_read(inode);
562 	return ret;
563 }
564 
565 static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
566 				    struct pipe_inode_info *pipe,
567 				    size_t len, unsigned int flags)
568 {
569 	struct inode *inode = file_inode(in);
570 	struct afs_vnode *vnode = AFS_FS_I(inode);
571 	struct afs_file *af = in->private_data;
572 	ssize_t ret;
573 
574 	ret = netfs_start_io_read(inode);
575 	if (ret < 0)
576 		return ret;
577 	ret = afs_validate(vnode, af->key);
578 	if (ret == 0)
579 		ret = filemap_splice_read(in, ppos, pipe, len, flags);
580 	netfs_end_io_read(inode);
581 	return ret;
582 }
583