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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
22static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
23static int afs_symlink_read_folio(struct file *file, struct folio *folio);
24
25static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
26static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
27 struct pipe_inode_info *pipe,
28 size_t len, unsigned int flags);
29static void afs_vm_open(struct vm_area_struct *area);
30static void afs_vm_close(struct vm_area_struct *area);
31static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff);
32
33const struct file_operations afs_file_operations = {
34 .open = afs_open,
35 .release = afs_release,
36 .llseek = generic_file_llseek,
37 .read_iter = afs_file_read_iter,
38 .write_iter = netfs_file_write_iter,
39 .mmap = afs_file_mmap,
40 .splice_read = afs_file_splice_read,
41 .splice_write = iter_file_splice_write,
42 .fsync = afs_fsync,
43 .lock = afs_lock,
44 .flock = afs_flock,
45};
46
47const struct inode_operations afs_file_inode_operations = {
48 .getattr = afs_getattr,
49 .setattr = afs_setattr,
50 .permission = afs_permission,
51};
52
53const struct address_space_operations afs_file_aops = {
54 .direct_IO = noop_direct_IO,
55 .read_folio = netfs_read_folio,
56 .readahead = netfs_readahead,
57 .dirty_folio = netfs_dirty_folio,
58 .release_folio = netfs_release_folio,
59 .invalidate_folio = netfs_invalidate_folio,
60 .migrate_folio = filemap_migrate_folio,
61 .writepages = afs_writepages,
62};
63
64const struct address_space_operations afs_symlink_aops = {
65 .read_folio = afs_symlink_read_folio,
66 .release_folio = netfs_release_folio,
67 .invalidate_folio = netfs_invalidate_folio,
68 .migrate_folio = filemap_migrate_folio,
69};
70
71static const struct vm_operations_struct afs_vm_ops = {
72 .open = afs_vm_open,
73 .close = afs_vm_close,
74 .fault = filemap_fault,
75 .map_pages = afs_vm_map_pages,
76 .page_mkwrite = afs_page_mkwrite,
77};
78
79/*
80 * Discard a pin on a writeback key.
81 */
82void afs_put_wb_key(struct afs_wb_key *wbk)
83{
84 if (wbk && refcount_dec_and_test(&wbk->usage)) {
85 key_put(wbk->key);
86 kfree(wbk);
87 }
88}
89
90/*
91 * Cache key for writeback.
92 */
93int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
94{
95 struct afs_wb_key *wbk, *p;
96
97 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
98 if (!wbk)
99 return -ENOMEM;
100 refcount_set(&wbk->usage, 2);
101 wbk->key = af->key;
102
103 spin_lock(&vnode->wb_lock);
104 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
105 if (p->key == wbk->key)
106 goto found;
107 }
108
109 key_get(wbk->key);
110 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
111 spin_unlock(&vnode->wb_lock);
112 af->wb = wbk;
113 return 0;
114
115found:
116 refcount_inc(&p->usage);
117 spin_unlock(&vnode->wb_lock);
118 af->wb = p;
119 kfree(wbk);
120 return 0;
121}
122
123/*
124 * open an AFS file or directory and attach a key to it
125 */
126int afs_open(struct inode *inode, struct file *file)
127{
128 struct afs_vnode *vnode = AFS_FS_I(inode);
129 struct afs_file *af;
130 struct key *key;
131 int ret;
132
133 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
134
135 key = afs_request_key(vnode->volume->cell);
136 if (IS_ERR(key)) {
137 ret = PTR_ERR(key);
138 goto error;
139 }
140
141 af = kzalloc(sizeof(*af), GFP_KERNEL);
142 if (!af) {
143 ret = -ENOMEM;
144 goto error_key;
145 }
146 af->key = key;
147
148 ret = afs_validate(vnode, key);
149 if (ret < 0)
150 goto error_af;
151
152 if (file->f_mode & FMODE_WRITE) {
153 ret = afs_cache_wb_key(vnode, af);
154 if (ret < 0)
155 goto error_af;
156 }
157
158 if (file->f_flags & O_TRUNC)
159 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
160
161 fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
162
163 file->private_data = af;
164 _leave(" = 0");
165 return 0;
166
167error_af:
168 kfree(af);
169error_key:
170 key_put(key);
171error:
172 _leave(" = %d", ret);
173 return ret;
174}
175
176/*
177 * release an AFS file or directory and discard its key
178 */
179int afs_release(struct inode *inode, struct file *file)
180{
181 struct afs_vnode_cache_aux aux;
182 struct afs_vnode *vnode = AFS_FS_I(inode);
183 struct afs_file *af = file->private_data;
184 loff_t i_size;
185 int ret = 0;
186
187 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
188
189 if ((file->f_mode & FMODE_WRITE))
190 ret = vfs_fsync(file, 0);
191
192 file->private_data = NULL;
193 if (af->wb)
194 afs_put_wb_key(af->wb);
195
196 if ((file->f_mode & FMODE_WRITE)) {
197 i_size = i_size_read(&vnode->netfs.inode);
198 afs_set_cache_aux(vnode, &aux);
199 fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
200 } else {
201 fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
202 }
203
204 key_put(af->key);
205 kfree(af);
206 afs_prune_wb_keys(vnode);
207 _leave(" = %d", ret);
208 return ret;
209}
210
211/*
212 * Allocate a new read record.
213 */
214struct afs_read *afs_alloc_read(gfp_t gfp)
215{
216 struct afs_read *req;
217
218 req = kzalloc(sizeof(struct afs_read), gfp);
219 if (req)
220 refcount_set(&req->usage, 1);
221
222 return req;
223}
224
225/*
226 * Dispose of a ref to a read record.
227 */
228void afs_put_read(struct afs_read *req)
229{
230 if (refcount_dec_and_test(&req->usage)) {
231 if (req->cleanup)
232 req->cleanup(req);
233 key_put(req->key);
234 kfree(req);
235 }
236}
237
238static void afs_fetch_data_notify(struct afs_operation *op)
239{
240 struct afs_read *req = op->fetch.req;
241 struct netfs_io_subrequest *subreq = req->subreq;
242 int error = afs_op_error(op);
243
244 req->error = error;
245 if (subreq) {
246 subreq->rreq->i_size = req->file_size;
247 if (req->pos + req->actual_len >= req->file_size)
248 __set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags);
249 netfs_read_subreq_terminated(subreq, error, false);
250 req->subreq = NULL;
251 } else if (req->done) {
252 req->done(req);
253 }
254}
255
256static void afs_fetch_data_success(struct afs_operation *op)
257{
258 struct afs_vnode *vnode = op->file[0].vnode;
259
260 _enter("op=%08x", op->debug_id);
261 afs_vnode_commit_status(op, &op->file[0]);
262 afs_stat_v(vnode, n_fetches);
263 atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
264 afs_fetch_data_notify(op);
265}
266
267static void afs_fetch_data_aborted(struct afs_operation *op)
268{
269 afs_check_for_remote_deletion(op);
270 afs_fetch_data_notify(op);
271}
272
273static void afs_fetch_data_put(struct afs_operation *op)
274{
275 op->fetch.req->error = afs_op_error(op);
276 afs_put_read(op->fetch.req);
277}
278
279static const struct afs_operation_ops afs_fetch_data_operation = {
280 .issue_afs_rpc = afs_fs_fetch_data,
281 .issue_yfs_rpc = yfs_fs_fetch_data,
282 .success = afs_fetch_data_success,
283 .aborted = afs_fetch_data_aborted,
284 .failed = afs_fetch_data_notify,
285 .put = afs_fetch_data_put,
286};
287
288/*
289 * Fetch file data from the volume.
290 */
291int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
292{
293 struct afs_operation *op;
294
295 _enter("%s{%llx:%llu.%u},%x,,,",
296 vnode->volume->name,
297 vnode->fid.vid,
298 vnode->fid.vnode,
299 vnode->fid.unique,
300 key_serial(req->key));
301
302 op = afs_alloc_operation(req->key, vnode->volume);
303 if (IS_ERR(op)) {
304 if (req->subreq)
305 netfs_read_subreq_terminated(req->subreq, PTR_ERR(op), false);
306 return PTR_ERR(op);
307 }
308
309 afs_op_set_vnode(op, 0, vnode);
310
311 op->fetch.req = afs_get_read(req);
312 op->ops = &afs_fetch_data_operation;
313 return afs_do_sync_operation(op);
314}
315
316static void afs_read_worker(struct work_struct *work)
317{
318 struct netfs_io_subrequest *subreq = container_of(work, struct netfs_io_subrequest, work);
319 struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
320 struct afs_read *fsreq;
321
322 fsreq = afs_alloc_read(GFP_NOFS);
323 if (!fsreq)
324 return netfs_read_subreq_terminated(subreq, -ENOMEM, false);
325
326 fsreq->subreq = subreq;
327 fsreq->pos = subreq->start + subreq->transferred;
328 fsreq->len = subreq->len - subreq->transferred;
329 fsreq->key = key_get(subreq->rreq->netfs_priv);
330 fsreq->vnode = vnode;
331 fsreq->iter = &subreq->io_iter;
332
333 trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
334 afs_fetch_data(fsreq->vnode, fsreq);
335 afs_put_read(fsreq);
336}
337
338static void afs_issue_read(struct netfs_io_subrequest *subreq)
339{
340 INIT_WORK(&subreq->work, afs_read_worker);
341 queue_work(system_long_wq, &subreq->work);
342}
343
344static int afs_symlink_read_folio(struct file *file, struct folio *folio)
345{
346 struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);
347 struct afs_read *fsreq;
348 int ret;
349
350 fsreq = afs_alloc_read(GFP_NOFS);
351 if (!fsreq)
352 return -ENOMEM;
353
354 fsreq->pos = folio_pos(folio);
355 fsreq->len = folio_size(folio);
356 fsreq->vnode = vnode;
357 fsreq->iter = &fsreq->def_iter;
358 iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
359 fsreq->pos, fsreq->len);
360
361 ret = afs_fetch_data(fsreq->vnode, fsreq);
362 if (ret == 0)
363 folio_mark_uptodate(folio);
364 folio_unlock(folio);
365 return ret;
366}
367
368static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
369{
370 if (file)
371 rreq->netfs_priv = key_get(afs_file_key(file));
372 rreq->rsize = 256 * 1024;
373 rreq->wsize = 256 * 1024 * 1024;
374 return 0;
375}
376
377static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
378 struct folio **foliop, void **_fsdata)
379{
380 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
381
382 return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
383}
384
385static void afs_free_request(struct netfs_io_request *rreq)
386{
387 key_put(rreq->netfs_priv);
388 afs_put_wb_key(rreq->netfs_priv2);
389}
390
391static void afs_update_i_size(struct inode *inode, loff_t new_i_size)
392{
393 struct afs_vnode *vnode = AFS_FS_I(inode);
394 loff_t i_size;
395
396 write_seqlock(&vnode->cb_lock);
397 i_size = i_size_read(&vnode->netfs.inode);
398 if (new_i_size > i_size) {
399 i_size_write(&vnode->netfs.inode, new_i_size);
400 inode_set_bytes(&vnode->netfs.inode, new_i_size);
401 }
402 write_sequnlock(&vnode->cb_lock);
403 fscache_update_cookie(afs_vnode_cache(vnode), NULL, &new_i_size);
404}
405
406static void afs_netfs_invalidate_cache(struct netfs_io_request *wreq)
407{
408 struct afs_vnode *vnode = AFS_FS_I(wreq->inode);
409
410 afs_invalidate_cache(vnode, 0);
411}
412
413const struct netfs_request_ops afs_req_ops = {
414 .init_request = afs_init_request,
415 .free_request = afs_free_request,
416 .check_write_begin = afs_check_write_begin,
417 .issue_read = afs_issue_read,
418 .update_i_size = afs_update_i_size,
419 .invalidate_cache = afs_netfs_invalidate_cache,
420 .begin_writeback = afs_begin_writeback,
421 .prepare_write = afs_prepare_write,
422 .issue_write = afs_issue_write,
423 .retry_request = afs_retry_request,
424};
425
426static void afs_add_open_mmap(struct afs_vnode *vnode)
427{
428 if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
429 down_write(&vnode->volume->open_mmaps_lock);
430
431 if (list_empty(&vnode->cb_mmap_link))
432 list_add_tail(&vnode->cb_mmap_link, &vnode->volume->open_mmaps);
433
434 up_write(&vnode->volume->open_mmaps_lock);
435 }
436}
437
438static void afs_drop_open_mmap(struct afs_vnode *vnode)
439{
440 if (atomic_add_unless(&vnode->cb_nr_mmap, -1, 1))
441 return;
442
443 down_write(&vnode->volume->open_mmaps_lock);
444
445 read_seqlock_excl(&vnode->cb_lock);
446 // the only place where ->cb_nr_mmap may hit 0
447 // see __afs_break_callback() for the other side...
448 if (atomic_dec_and_test(&vnode->cb_nr_mmap))
449 list_del_init(&vnode->cb_mmap_link);
450 read_sequnlock_excl(&vnode->cb_lock);
451
452 up_write(&vnode->volume->open_mmaps_lock);
453 flush_work(&vnode->cb_work);
454}
455
456/*
457 * Handle setting up a memory mapping on an AFS file.
458 */
459static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
460{
461 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
462 int ret;
463
464 afs_add_open_mmap(vnode);
465
466 ret = generic_file_mmap(file, vma);
467 if (ret == 0)
468 vma->vm_ops = &afs_vm_ops;
469 else
470 afs_drop_open_mmap(vnode);
471 return ret;
472}
473
474static void afs_vm_open(struct vm_area_struct *vma)
475{
476 afs_add_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
477}
478
479static void afs_vm_close(struct vm_area_struct *vma)
480{
481 afs_drop_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
482}
483
484static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
485{
486 struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
487
488 if (afs_check_validity(vnode))
489 return filemap_map_pages(vmf, start_pgoff, end_pgoff);
490 return 0;
491}
492
493static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
494{
495 struct inode *inode = file_inode(iocb->ki_filp);
496 struct afs_vnode *vnode = AFS_FS_I(inode);
497 struct afs_file *af = iocb->ki_filp->private_data;
498 ssize_t ret;
499
500 if (iocb->ki_flags & IOCB_DIRECT)
501 return netfs_unbuffered_read_iter(iocb, iter);
502
503 ret = netfs_start_io_read(inode);
504 if (ret < 0)
505 return ret;
506 ret = afs_validate(vnode, af->key);
507 if (ret == 0)
508 ret = filemap_read(iocb, iter, 0);
509 netfs_end_io_read(inode);
510 return ret;
511}
512
513static ssize_t afs_file_splice_read(struct file *in, loff_t *ppos,
514 struct pipe_inode_info *pipe,
515 size_t len, unsigned int flags)
516{
517 struct inode *inode = file_inode(in);
518 struct afs_vnode *vnode = AFS_FS_I(inode);
519 struct afs_file *af = in->private_data;
520 ssize_t ret;
521
522 ret = netfs_start_io_read(inode);
523 if (ret < 0)
524 return ret;
525 ret = afs_validate(vnode, af->key);
526 if (ret == 0)
527 ret = filemap_splice_read(in, ppos, pipe, len, flags);
528 netfs_end_io_read(inode);
529 return ret;
530}
1/* AFS filesystem file handling
2 *
3 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/fs.h>
16#include <linux/pagemap.h>
17#include <linux/writeback.h>
18#include <linux/gfp.h>
19#include "internal.h"
20
21static int afs_readpage(struct file *file, struct page *page);
22static void afs_invalidatepage(struct page *page, unsigned long offset);
23static int afs_releasepage(struct page *page, gfp_t gfp_flags);
24static int afs_launder_page(struct page *page);
25
26static int afs_readpages(struct file *filp, struct address_space *mapping,
27 struct list_head *pages, unsigned nr_pages);
28
29const struct file_operations afs_file_operations = {
30 .open = afs_open,
31 .release = afs_release,
32 .llseek = generic_file_llseek,
33 .read = do_sync_read,
34 .write = do_sync_write,
35 .aio_read = generic_file_aio_read,
36 .aio_write = afs_file_write,
37 .mmap = generic_file_readonly_mmap,
38 .splice_read = generic_file_splice_read,
39 .fsync = afs_fsync,
40 .lock = afs_lock,
41 .flock = afs_flock,
42};
43
44const struct inode_operations afs_file_inode_operations = {
45 .getattr = afs_getattr,
46 .setattr = afs_setattr,
47 .permission = afs_permission,
48};
49
50const struct address_space_operations afs_fs_aops = {
51 .readpage = afs_readpage,
52 .readpages = afs_readpages,
53 .set_page_dirty = afs_set_page_dirty,
54 .launder_page = afs_launder_page,
55 .releasepage = afs_releasepage,
56 .invalidatepage = afs_invalidatepage,
57 .write_begin = afs_write_begin,
58 .write_end = afs_write_end,
59 .writepage = afs_writepage,
60 .writepages = afs_writepages,
61};
62
63/*
64 * open an AFS file or directory and attach a key to it
65 */
66int afs_open(struct inode *inode, struct file *file)
67{
68 struct afs_vnode *vnode = AFS_FS_I(inode);
69 struct key *key;
70 int ret;
71
72 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
73
74 key = afs_request_key(vnode->volume->cell);
75 if (IS_ERR(key)) {
76 _leave(" = %ld [key]", PTR_ERR(key));
77 return PTR_ERR(key);
78 }
79
80 ret = afs_validate(vnode, key);
81 if (ret < 0) {
82 _leave(" = %d [val]", ret);
83 return ret;
84 }
85
86 file->private_data = key;
87 _leave(" = 0");
88 return 0;
89}
90
91/*
92 * release an AFS file or directory and discard its key
93 */
94int afs_release(struct inode *inode, struct file *file)
95{
96 struct afs_vnode *vnode = AFS_FS_I(inode);
97
98 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
99
100 key_put(file->private_data);
101 _leave(" = 0");
102 return 0;
103}
104
105#ifdef CONFIG_AFS_FSCACHE
106/*
107 * deal with notification that a page was read from the cache
108 */
109static void afs_file_readpage_read_complete(struct page *page,
110 void *data,
111 int error)
112{
113 _enter("%p,%p,%d", page, data, error);
114
115 /* if the read completes with an error, we just unlock the page and let
116 * the VM reissue the readpage */
117 if (!error)
118 SetPageUptodate(page);
119 unlock_page(page);
120}
121#endif
122
123/*
124 * read page from file, directory or symlink, given a key to use
125 */
126int afs_page_filler(void *data, struct page *page)
127{
128 struct inode *inode = page->mapping->host;
129 struct afs_vnode *vnode = AFS_FS_I(inode);
130 struct key *key = data;
131 size_t len;
132 off_t offset;
133 int ret;
134
135 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
136
137 BUG_ON(!PageLocked(page));
138
139 ret = -ESTALE;
140 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
141 goto error;
142
143 /* is it cached? */
144#ifdef CONFIG_AFS_FSCACHE
145 ret = fscache_read_or_alloc_page(vnode->cache,
146 page,
147 afs_file_readpage_read_complete,
148 NULL,
149 GFP_KERNEL);
150#else
151 ret = -ENOBUFS;
152#endif
153 switch (ret) {
154 /* read BIO submitted (page in cache) */
155 case 0:
156 break;
157
158 /* page not yet cached */
159 case -ENODATA:
160 _debug("cache said ENODATA");
161 goto go_on;
162
163 /* page will not be cached */
164 case -ENOBUFS:
165 _debug("cache said ENOBUFS");
166 default:
167 go_on:
168 offset = page->index << PAGE_CACHE_SHIFT;
169 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
170
171 /* read the contents of the file from the server into the
172 * page */
173 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
174 if (ret < 0) {
175 if (ret == -ENOENT) {
176 _debug("got NOENT from server"
177 " - marking file deleted and stale");
178 set_bit(AFS_VNODE_DELETED, &vnode->flags);
179 ret = -ESTALE;
180 }
181
182#ifdef CONFIG_AFS_FSCACHE
183 fscache_uncache_page(vnode->cache, page);
184#endif
185 BUG_ON(PageFsCache(page));
186 goto error;
187 }
188
189 SetPageUptodate(page);
190
191 /* send the page to the cache */
192#ifdef CONFIG_AFS_FSCACHE
193 if (PageFsCache(page) &&
194 fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
195 fscache_uncache_page(vnode->cache, page);
196 BUG_ON(PageFsCache(page));
197 }
198#endif
199 unlock_page(page);
200 }
201
202 _leave(" = 0");
203 return 0;
204
205error:
206 SetPageError(page);
207 unlock_page(page);
208 _leave(" = %d", ret);
209 return ret;
210}
211
212/*
213 * read page from file, directory or symlink, given a file to nominate the key
214 * to be used
215 */
216static int afs_readpage(struct file *file, struct page *page)
217{
218 struct key *key;
219 int ret;
220
221 if (file) {
222 key = file->private_data;
223 ASSERT(key != NULL);
224 ret = afs_page_filler(key, page);
225 } else {
226 struct inode *inode = page->mapping->host;
227 key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
228 if (IS_ERR(key)) {
229 ret = PTR_ERR(key);
230 } else {
231 ret = afs_page_filler(key, page);
232 key_put(key);
233 }
234 }
235 return ret;
236}
237
238/*
239 * read a set of pages
240 */
241static int afs_readpages(struct file *file, struct address_space *mapping,
242 struct list_head *pages, unsigned nr_pages)
243{
244 struct key *key = file->private_data;
245 struct afs_vnode *vnode;
246 int ret = 0;
247
248 _enter("{%d},{%lu},,%d",
249 key_serial(key), mapping->host->i_ino, nr_pages);
250
251 ASSERT(key != NULL);
252
253 vnode = AFS_FS_I(mapping->host);
254 if (vnode->flags & AFS_VNODE_DELETED) {
255 _leave(" = -ESTALE");
256 return -ESTALE;
257 }
258
259 /* attempt to read as many of the pages as possible */
260#ifdef CONFIG_AFS_FSCACHE
261 ret = fscache_read_or_alloc_pages(vnode->cache,
262 mapping,
263 pages,
264 &nr_pages,
265 afs_file_readpage_read_complete,
266 NULL,
267 mapping_gfp_mask(mapping));
268#else
269 ret = -ENOBUFS;
270#endif
271
272 switch (ret) {
273 /* all pages are being read from the cache */
274 case 0:
275 BUG_ON(!list_empty(pages));
276 BUG_ON(nr_pages != 0);
277 _leave(" = 0 [reading all]");
278 return 0;
279
280 /* there were pages that couldn't be read from the cache */
281 case -ENODATA:
282 case -ENOBUFS:
283 break;
284
285 /* other error */
286 default:
287 _leave(" = %d", ret);
288 return ret;
289 }
290
291 /* load the missing pages from the network */
292 ret = read_cache_pages(mapping, pages, afs_page_filler, key);
293
294 _leave(" = %d [netting]", ret);
295 return ret;
296}
297
298/*
299 * write back a dirty page
300 */
301static int afs_launder_page(struct page *page)
302{
303 _enter("{%lu}", page->index);
304
305 return 0;
306}
307
308/*
309 * invalidate part or all of a page
310 * - release a page and clean up its private data if offset is 0 (indicating
311 * the entire page)
312 */
313static void afs_invalidatepage(struct page *page, unsigned long offset)
314{
315 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
316
317 _enter("{%lu},%lu", page->index, offset);
318
319 BUG_ON(!PageLocked(page));
320
321 /* we clean up only if the entire page is being invalidated */
322 if (offset == 0) {
323#ifdef CONFIG_AFS_FSCACHE
324 if (PageFsCache(page)) {
325 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
326 fscache_wait_on_page_write(vnode->cache, page);
327 fscache_uncache_page(vnode->cache, page);
328 }
329#endif
330
331 if (PagePrivate(page)) {
332 if (wb && !PageWriteback(page)) {
333 set_page_private(page, 0);
334 afs_put_writeback(wb);
335 }
336
337 if (!page_private(page))
338 ClearPagePrivate(page);
339 }
340 }
341
342 _leave("");
343}
344
345/*
346 * release a page and clean up its private state if it's not busy
347 * - return true if the page can now be released, false if not
348 */
349static int afs_releasepage(struct page *page, gfp_t gfp_flags)
350{
351 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
352 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
353
354 _enter("{{%x:%u}[%lu],%lx},%x",
355 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
356 gfp_flags);
357
358 /* deny if page is being written to the cache and the caller hasn't
359 * elected to wait */
360#ifdef CONFIG_AFS_FSCACHE
361 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
362 _leave(" = F [cache busy]");
363 return 0;
364 }
365#endif
366
367 if (PagePrivate(page)) {
368 if (wb) {
369 set_page_private(page, 0);
370 afs_put_writeback(wb);
371 }
372 ClearPagePrivate(page);
373 }
374
375 /* indicate that the page can be released */
376 _leave(" = T");
377 return 1;
378}