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 "internal.h"
20
21 static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
22 static int afs_symlink_read_folio(struct file *file, struct folio *folio);
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
32 const struct file_operations afs_file_operations = {
33 .open = afs_open,
34 .release = afs_release,
35 .llseek = generic_file_llseek,
36 .read_iter = afs_file_read_iter,
37 .write_iter = netfs_file_write_iter,
38 .mmap = afs_file_mmap,
39 .splice_read = afs_file_splice_read,
40 .splice_write = iter_file_splice_write,
41 .fsync = afs_fsync,
42 .lock = afs_lock,
43 .flock = afs_flock,
44 };
45
46 const struct inode_operations afs_file_inode_operations = {
47 .getattr = afs_getattr,
48 .setattr = afs_setattr,
49 .permission = afs_permission,
50 };
51
52 const struct address_space_operations afs_file_aops = {
53 .direct_IO = noop_direct_IO,
54 .read_folio = netfs_read_folio,
55 .readahead = netfs_readahead,
56 .dirty_folio = netfs_dirty_folio,
57 .release_folio = netfs_release_folio,
58 .invalidate_folio = netfs_invalidate_folio,
59 .migrate_folio = filemap_migrate_folio,
60 .writepages = afs_writepages,
61 };
62
63 const struct address_space_operations afs_symlink_aops = {
64 .read_folio = afs_symlink_read_folio,
65 .release_folio = netfs_release_folio,
66 .invalidate_folio = netfs_invalidate_folio,
67 .migrate_folio = filemap_migrate_folio,
68 };
69
70 static const struct vm_operations_struct afs_vm_ops = {
71 .open = afs_vm_open,
72 .close = afs_vm_close,
73 .fault = filemap_fault,
74 .map_pages = afs_vm_map_pages,
75 .page_mkwrite = afs_page_mkwrite,
76 };
77
78 /*
79 * Discard a pin on a writeback key.
80 */
81 void afs_put_wb_key(struct afs_wb_key *wbk)
82 {
83 if (wbk && refcount_dec_and_test(&wbk->usage)) {
84 key_put(wbk->key);
85 kfree(wbk);
86 }
87 }
88
89 /*
90 * Cache key for writeback.
91 */
92 int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
93 {
94 struct afs_wb_key *wbk, *p;
95
96 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
97 if (!wbk)
98 return -ENOMEM;
99 refcount_set(&wbk->usage, 2);
100 wbk->key = af->key;
101
102 spin_lock(&vnode->wb_lock);
103 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
104 if (p->key == wbk->key)
105 goto found;
106 }
107
108 key_get(wbk->key);
109 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
110 spin_unlock(&vnode->wb_lock);
111 af->wb = wbk;
112 return 0;
113
114 found:
115 refcount_inc(&p->usage);
116 spin_unlock(&vnode->wb_lock);
117 af->wb = p;
118 kfree(wbk);
119 return 0;
120 }
121
122 /*
123 * open an AFS file or directory and attach a key to it
124 */
125 int afs_open(struct inode *inode, struct file *file)
126 {
127 struct afs_vnode *vnode = AFS_FS_I(inode);
128 struct afs_file *af;
129 struct key *key;
130 int ret;
131
132 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
133
134 key = afs_request_key(vnode->volume->cell);
135 if (IS_ERR(key)) {
136 ret = PTR_ERR(key);
137 goto error;
138 }
139
140 af = kzalloc(sizeof(*af), GFP_KERNEL);
141 if (!af) {
142 ret = -ENOMEM;
143 goto error_key;
144 }
145 af->key = key;
146
147 ret = afs_validate(vnode, key);
148 if (ret < 0)
149 goto error_af;
150
151 if (file->f_mode & FMODE_WRITE) {
152 ret = afs_cache_wb_key(vnode, af);
153 if (ret < 0)
154 goto error_af;
155 }
156
157 if (file->f_flags & O_TRUNC)
158 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
159
160 fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
161
162 file->private_data = af;
163 _leave(" = 0");
164 return 0;
165
166 error_af:
167 kfree(af);
168 error_key:
169 key_put(key);
170 error:
171 _leave(" = %d", ret);
172 return ret;
173 }
174
175 /*
176 * release an AFS file or directory and discard its key
177 */
178 int afs_release(struct inode *inode, struct file *file)
179 {
180 struct afs_vnode_cache_aux aux;
181 struct afs_vnode *vnode = AFS_FS_I(inode);
182 struct afs_file *af = file->private_data;
183 loff_t i_size;
184 int ret = 0;
185
186 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
187
188 if ((file->f_mode & FMODE_WRITE))
189 ret = vfs_fsync(file, 0);
190
191 file->private_data = NULL;
192 if (af->wb)
193 afs_put_wb_key(af->wb);
194
195 if ((file->f_mode & FMODE_WRITE)) {
196 i_size = i_size_read(&vnode->netfs.inode);
197 afs_set_cache_aux(vnode, &aux);
198 fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
199 } else {
200 fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
201 }
202
203 key_put(af->key);
204 kfree(af);
205 afs_prune_wb_keys(vnode);
206 _leave(" = %d", ret);
207 return ret;
208 }
209
210 /*
211 * Allocate a new read record.
212 */
213 struct afs_read *afs_alloc_read(gfp_t gfp)
214 {
215 struct afs_read *req;
216
217 req = kzalloc(sizeof(struct afs_read), gfp);
218 if (req)
219 refcount_set(&req->usage, 1);
220
221 return req;
222 }
223
224 /*
225 * Dispose of a ref to a read record.
226 */
227 void afs_put_read(struct afs_read *req)
228 {
229 if (refcount_dec_and_test(&req->usage)) {
230 if (req->cleanup)
231 req->cleanup(req);
232 key_put(req->key);
233 kfree(req);
234 }
235 }
236
237 static void afs_fetch_data_notify(struct afs_operation *op)
238 {
239 struct afs_read *req = op->fetch.req;
240 struct netfs_io_subrequest *subreq = req->subreq;
241 int error = afs_op_error(op);
242
243 req->error = error;
244 if (subreq) {
245 if (subreq->rreq->origin != NETFS_DIO_READ)
246 __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
247 netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
248 req->subreq = NULL;
249 } else if (req->done) {
250 req->done(req);
251 }
252 }
253
254 static void afs_fetch_data_success(struct afs_operation *op)
255 {
256 struct afs_vnode *vnode = op->file[0].vnode;
257
258 _enter("op=%08x", op->debug_id);
259 afs_vnode_commit_status(op, &op->file[0]);
260 afs_stat_v(vnode, n_fetches);
261 atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
262 afs_fetch_data_notify(op);
263 }
264
265 static void afs_fetch_data_put(struct afs_operation *op)
266 {
267 op->fetch.req->error = afs_op_error(op);
268 afs_put_read(op->fetch.req);
269 }
270
271 static const struct afs_operation_ops afs_fetch_data_operation = {
272 .issue_afs_rpc = afs_fs_fetch_data,
273 .issue_yfs_rpc = yfs_fs_fetch_data,
274 .success = afs_fetch_data_success,
275 .aborted = afs_check_for_remote_deletion,
276 .failed = afs_fetch_data_notify,
277 .put = afs_fetch_data_put,
278 };
279
280 /*
281 * Fetch file data from the volume.
282 */
283 int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
284 {
285 struct afs_operation *op;
286
287 _enter("%s{%llx:%llu.%u},%x,,,",
288 vnode->volume->name,
289 vnode->fid.vid,
290 vnode->fid.vnode,
291 vnode->fid.unique,
292 key_serial(req->key));
293
294 op = afs_alloc_operation(req->key, vnode->volume);
295 if (IS_ERR(op)) {
296 if (req->subreq)
297 netfs_subreq_terminated(req->subreq, PTR_ERR(op), false);
298 return PTR_ERR(op);
299 }
300
301 afs_op_set_vnode(op, 0, vnode);
302
303 op->fetch.req = afs_get_read(req);
304 op->ops = &afs_fetch_data_operation;
305 return afs_do_sync_operation(op);
306 }
307
308 static void afs_issue_read(struct netfs_io_subrequest *subreq)
309 {
310 struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
311 struct afs_read *fsreq;
312
313 fsreq = afs_alloc_read(GFP_NOFS);
314 if (!fsreq)
315 return netfs_subreq_terminated(subreq, -ENOMEM, false);
316
317 fsreq->subreq = subreq;
318 fsreq->pos = subreq->start + subreq->transferred;
319 fsreq->len = subreq->len - subreq->transferred;
320 fsreq->key = key_get(subreq->rreq->netfs_priv);
321 fsreq->vnode = vnode;
322 fsreq->iter = &subreq->io_iter;
323
324 afs_fetch_data(fsreq->vnode, fsreq);
325 afs_put_read(fsreq);
326 }
327
328 static int afs_symlink_read_folio(struct file *file, struct folio *folio)
329 {
330 struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);
331 struct afs_read *fsreq;
332 int ret;
333
334 fsreq = afs_alloc_read(GFP_NOFS);
335 if (!fsreq)
336 return -ENOMEM;
337
338 fsreq->pos = folio_pos(folio);
339 fsreq->len = folio_size(folio);
340 fsreq->vnode = vnode;
341 fsreq->iter = &fsreq->def_iter;
342 iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
343 fsreq->pos, fsreq->len);
344
345 ret = afs_fetch_data(fsreq->vnode, fsreq);
346 if (ret == 0)
347 folio_mark_uptodate(folio);
348 folio_unlock(folio);
349 return ret;
350 }
351
352 static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
353 {
354 if (file)
355 rreq->netfs_priv = key_get(afs_file_key(file));
356 rreq->rsize = 256 * 1024;
357 rreq->wsize = 256 * 1024 * 1024;
358 return 0;
359 }
360
361 static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
362 struct folio **foliop, void **_fsdata)
363 {
364 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
365
366 return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
367 }
368
369 static void afs_free_request(struct netfs_io_request *rreq)
370 {
371 key_put(rreq->netfs_priv);
372 afs_put_wb_key(rreq->netfs_priv2);
373 }
374
375 static void afs_update_i_size(struct inode *inode, loff_t new_i_size)
376 {
377 struct afs_vnode *vnode = AFS_FS_I(inode);
378 loff_t i_size;
379
380 write_seqlock(&vnode->cb_lock);
381 i_size = i_size_read(&vnode->netfs.inode);
382 if (new_i_size > i_size) {
383 i_size_write(&vnode->netfs.inode, new_i_size);
384 inode_set_bytes(&vnode->netfs.inode, new_i_size);
385 }
386 write_sequnlock(&vnode->cb_lock);
387 fscache_update_cookie(afs_vnode_cache(vnode), NULL, &new_i_size);
388 }
389
390 static void afs_netfs_invalidate_cache(struct netfs_io_request *wreq)
391 {
392 struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
393
394 afs_invalidate_cache(vnode, 0);
395 }
396
397 const struct netfs_request_ops afs_req_ops = {
398 .init_request = afs_init_request,
399 .free_request = afs_free_request,
400 .check_write_begin = afs_check_write_begin,
401 .issue_read = afs_issue_read,
402 .update_i_size = afs_update_i_size,
403 .invalidate_cache = afs_netfs_invalidate_cache,
404 .begin_writeback = afs_begin_writeback,
405 .prepare_write = afs_prepare_write,
406 .issue_write = afs_issue_write,
407 .retry_request = afs_retry_request,
408 };
409
410 static void afs_add_open_mmap(struct afs_vnode *vnode)
411 {
412 if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
413 down_write(&vnode->volume->open_mmaps_lock);
414
415 if (list_empty(&vnode->cb_mmap_link))
416 list_add_tail(&vnode->cb_mmap_link, &vnode->volume->open_mmaps);
417
418 up_write(&vnode->volume->open_mmaps_lock);
419 }
420 }
421
422 static void afs_drop_open_mmap(struct afs_vnode *vnode)
423 {
424 if (atomic_add_unless(&vnode->cb_nr_mmap, -1, 1))
425 return;
426
427 down_write(&vnode->volume->open_mmaps_lock);
428
429 read_seqlock_excl(&vnode->cb_lock);
430 // the only place where ->cb_nr_mmap may hit 0
431 // see __afs_break_callback() for the other side...
432 if (atomic_dec_and_test(&vnode->cb_nr_mmap))
433 list_del_init(&vnode->cb_mmap_link);
434 read_sequnlock_excl(&vnode->cb_lock);
435
436 up_write(&vnode->volume->open_mmaps_lock);
437 flush_work(&vnode->cb_work);
438 }
439
440 /*
441 * Handle setting up a memory mapping on an AFS file.
442 */
443 static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
444 {
445 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
446 int ret;
447
448 afs_add_open_mmap(vnode);
449
450 ret = generic_file_mmap(file, vma);
451 if (ret == 0)
452 vma->vm_ops = &afs_vm_ops;
453 else
454 afs_drop_open_mmap(vnode);
455 return ret;
456 }
457
458 static void afs_vm_open(struct vm_area_struct *vma)
459 {
460 afs_add_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
461 }
462
463 static void afs_vm_close(struct vm_area_struct *vma)
464 {
465 afs_drop_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
466 }
467
468 static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
469 {
470 struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
471
472 if (afs_check_validity(vnode))
473 return filemap_map_pages(vmf, start_pgoff, end_pgoff);
474 return 0;
475 }
476
477 static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
478 {
479 struct inode *inode = file_inode(iocb->ki_filp);
480 struct afs_vnode *vnode = AFS_FS_I(inode);
481 struct afs_file *af = iocb->ki_filp->private_data;
482 ssize_t ret;
483
484 if (iocb->ki_flags & IOCB_DIRECT)
485 return netfs_unbuffered_read_iter(iocb, iter);
486
487 ret = netfs_start_io_read(inode);
488 if (ret < 0)
489 return ret;
490 ret = afs_validate(vnode, af->key);
491 if (ret == 0)
492 ret = filemap_read(iocb, iter, 0);
493 netfs_end_io_read(inode);
494 return ret;
495 }
496
497 static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
498 struct pipe_inode_info *pipe,
499 size_t len, unsigned int flags)
500 {
501 struct inode *inode = file_inode(in);
502 struct afs_vnode *vnode = AFS_FS_I(inode);
503 struct afs_file *af = in->private_data;
504 ssize_t ret;
505
506 ret = netfs_start_io_read(inode);
507 if (ret < 0)
508 return ret;
509 ret = afs_validate(vnode, af->key);
510 if (ret == 0)
511 ret = filemap_splice_read(in, ppos, pipe, len, flags);
512 netfs_end_io_read(inode);
513 return ret;
514 }
515
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