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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 int offset,
23 unsigned int length);
24static int afs_releasepage(struct page *page, gfp_t gfp_flags);
25static int afs_launder_page(struct page *page);
26
27static int afs_readpages(struct file *filp, struct address_space *mapping,
28 struct list_head *pages, unsigned nr_pages);
29
30const struct file_operations afs_file_operations = {
31 .open = afs_open,
32 .release = afs_release,
33 .llseek = generic_file_llseek,
34 .read = do_sync_read,
35 .write = do_sync_write,
36 .aio_read = generic_file_aio_read,
37 .aio_write = afs_file_write,
38 .mmap = generic_file_readonly_mmap,
39 .splice_read = generic_file_splice_read,
40 .fsync = afs_fsync,
41 .lock = afs_lock,
42 .flock = afs_flock,
43};
44
45const struct inode_operations afs_file_inode_operations = {
46 .getattr = afs_getattr,
47 .setattr = afs_setattr,
48 .permission = afs_permission,
49};
50
51const struct address_space_operations afs_fs_aops = {
52 .readpage = afs_readpage,
53 .readpages = afs_readpages,
54 .set_page_dirty = afs_set_page_dirty,
55 .launder_page = afs_launder_page,
56 .releasepage = afs_releasepage,
57 .invalidatepage = afs_invalidatepage,
58 .write_begin = afs_write_begin,
59 .write_end = afs_write_end,
60 .writepage = afs_writepage,
61 .writepages = afs_writepages,
62};
63
64/*
65 * open an AFS file or directory and attach a key to it
66 */
67int afs_open(struct inode *inode, struct file *file)
68{
69 struct afs_vnode *vnode = AFS_FS_I(inode);
70 struct key *key;
71 int ret;
72
73 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
74
75 key = afs_request_key(vnode->volume->cell);
76 if (IS_ERR(key)) {
77 _leave(" = %ld [key]", PTR_ERR(key));
78 return PTR_ERR(key);
79 }
80
81 ret = afs_validate(vnode, key);
82 if (ret < 0) {
83 _leave(" = %d [val]", ret);
84 return ret;
85 }
86
87 file->private_data = key;
88 _leave(" = 0");
89 return 0;
90}
91
92/*
93 * release an AFS file or directory and discard its key
94 */
95int afs_release(struct inode *inode, struct file *file)
96{
97 struct afs_vnode *vnode = AFS_FS_I(inode);
98
99 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
100
101 key_put(file->private_data);
102 _leave(" = 0");
103 return 0;
104}
105
106#ifdef CONFIG_AFS_FSCACHE
107/*
108 * deal with notification that a page was read from the cache
109 */
110static void afs_file_readpage_read_complete(struct page *page,
111 void *data,
112 int error)
113{
114 _enter("%p,%p,%d", page, data, error);
115
116 /* if the read completes with an error, we just unlock the page and let
117 * the VM reissue the readpage */
118 if (!error)
119 SetPageUptodate(page);
120 unlock_page(page);
121}
122#endif
123
124/*
125 * read page from file, directory or symlink, given a key to use
126 */
127int afs_page_filler(void *data, struct page *page)
128{
129 struct inode *inode = page->mapping->host;
130 struct afs_vnode *vnode = AFS_FS_I(inode);
131 struct key *key = data;
132 size_t len;
133 off_t offset;
134 int ret;
135
136 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
137
138 BUG_ON(!PageLocked(page));
139
140 ret = -ESTALE;
141 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
142 goto error;
143
144 /* is it cached? */
145#ifdef CONFIG_AFS_FSCACHE
146 ret = fscache_read_or_alloc_page(vnode->cache,
147 page,
148 afs_file_readpage_read_complete,
149 NULL,
150 GFP_KERNEL);
151#else
152 ret = -ENOBUFS;
153#endif
154 switch (ret) {
155 /* read BIO submitted (page in cache) */
156 case 0:
157 break;
158
159 /* page not yet cached */
160 case -ENODATA:
161 _debug("cache said ENODATA");
162 goto go_on;
163
164 /* page will not be cached */
165 case -ENOBUFS:
166 _debug("cache said ENOBUFS");
167 default:
168 go_on:
169 offset = page->index << PAGE_CACHE_SHIFT;
170 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
171
172 /* read the contents of the file from the server into the
173 * page */
174 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
175 if (ret < 0) {
176 if (ret == -ENOENT) {
177 _debug("got NOENT from server"
178 " - marking file deleted and stale");
179 set_bit(AFS_VNODE_DELETED, &vnode->flags);
180 ret = -ESTALE;
181 }
182
183#ifdef CONFIG_AFS_FSCACHE
184 fscache_uncache_page(vnode->cache, page);
185#endif
186 BUG_ON(PageFsCache(page));
187 goto error;
188 }
189
190 SetPageUptodate(page);
191
192 /* send the page to the cache */
193#ifdef CONFIG_AFS_FSCACHE
194 if (PageFsCache(page) &&
195 fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
196 fscache_uncache_page(vnode->cache, page);
197 BUG_ON(PageFsCache(page));
198 }
199#endif
200 unlock_page(page);
201 }
202
203 _leave(" = 0");
204 return 0;
205
206error:
207 SetPageError(page);
208 unlock_page(page);
209 _leave(" = %d", ret);
210 return ret;
211}
212
213/*
214 * read page from file, directory or symlink, given a file to nominate the key
215 * to be used
216 */
217static int afs_readpage(struct file *file, struct page *page)
218{
219 struct key *key;
220 int ret;
221
222 if (file) {
223 key = file->private_data;
224 ASSERT(key != NULL);
225 ret = afs_page_filler(key, page);
226 } else {
227 struct inode *inode = page->mapping->host;
228 key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
229 if (IS_ERR(key)) {
230 ret = PTR_ERR(key);
231 } else {
232 ret = afs_page_filler(key, page);
233 key_put(key);
234 }
235 }
236 return ret;
237}
238
239/*
240 * read a set of pages
241 */
242static int afs_readpages(struct file *file, struct address_space *mapping,
243 struct list_head *pages, unsigned nr_pages)
244{
245 struct key *key = file->private_data;
246 struct afs_vnode *vnode;
247 int ret = 0;
248
249 _enter("{%d},{%lu},,%d",
250 key_serial(key), mapping->host->i_ino, nr_pages);
251
252 ASSERT(key != NULL);
253
254 vnode = AFS_FS_I(mapping->host);
255 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
256 _leave(" = -ESTALE");
257 return -ESTALE;
258 }
259
260 /* attempt to read as many of the pages as possible */
261#ifdef CONFIG_AFS_FSCACHE
262 ret = fscache_read_or_alloc_pages(vnode->cache,
263 mapping,
264 pages,
265 &nr_pages,
266 afs_file_readpage_read_complete,
267 NULL,
268 mapping_gfp_mask(mapping));
269#else
270 ret = -ENOBUFS;
271#endif
272
273 switch (ret) {
274 /* all pages are being read from the cache */
275 case 0:
276 BUG_ON(!list_empty(pages));
277 BUG_ON(nr_pages != 0);
278 _leave(" = 0 [reading all]");
279 return 0;
280
281 /* there were pages that couldn't be read from the cache */
282 case -ENODATA:
283 case -ENOBUFS:
284 break;
285
286 /* other error */
287 default:
288 _leave(" = %d", ret);
289 return ret;
290 }
291
292 /* load the missing pages from the network */
293 ret = read_cache_pages(mapping, pages, afs_page_filler, key);
294
295 _leave(" = %d [netting]", ret);
296 return ret;
297}
298
299/*
300 * write back a dirty page
301 */
302static int afs_launder_page(struct page *page)
303{
304 _enter("{%lu}", page->index);
305
306 return 0;
307}
308
309/*
310 * invalidate part or all of a page
311 * - release a page and clean up its private data if offset is 0 (indicating
312 * the entire page)
313 */
314static void afs_invalidatepage(struct page *page, unsigned int offset,
315 unsigned int length)
316{
317 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
318
319 _enter("{%lu},%u,%u", page->index, offset, length);
320
321 BUG_ON(!PageLocked(page));
322
323 /* we clean up only if the entire page is being invalidated */
324 if (offset == 0 && length == PAGE_CACHE_SIZE) {
325#ifdef CONFIG_AFS_FSCACHE
326 if (PageFsCache(page)) {
327 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
328 fscache_wait_on_page_write(vnode->cache, page);
329 fscache_uncache_page(vnode->cache, page);
330 }
331#endif
332
333 if (PagePrivate(page)) {
334 if (wb && !PageWriteback(page)) {
335 set_page_private(page, 0);
336 afs_put_writeback(wb);
337 }
338
339 if (!page_private(page))
340 ClearPagePrivate(page);
341 }
342 }
343
344 _leave("");
345}
346
347/*
348 * release a page and clean up its private state if it's not busy
349 * - return true if the page can now be released, false if not
350 */
351static int afs_releasepage(struct page *page, gfp_t gfp_flags)
352{
353 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
354 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
355
356 _enter("{{%x:%u}[%lu],%lx},%x",
357 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
358 gfp_flags);
359
360 /* deny if page is being written to the cache and the caller hasn't
361 * elected to wait */
362#ifdef CONFIG_AFS_FSCACHE
363 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
364 _leave(" = F [cache busy]");
365 return 0;
366 }
367#endif
368
369 if (PagePrivate(page)) {
370 if (wb) {
371 set_page_private(page, 0);
372 afs_put_writeback(wb);
373 }
374 ClearPagePrivate(page);
375 }
376
377 /* indicate that the page can be released */
378 _leave(" = T");
379 return 1;
380}
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
21static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
22static int afs_symlink_read_folio(struct file *file, struct folio *folio);
23static void afs_invalidate_folio(struct folio *folio, size_t offset,
24 size_t length);
25static bool afs_release_folio(struct folio *folio, gfp_t gfp_flags);
26
27static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
28static void afs_vm_open(struct vm_area_struct *area);
29static void afs_vm_close(struct vm_area_struct *area);
30static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff);
31
32const 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 = afs_file_write,
38 .mmap = afs_file_mmap,
39 .splice_read = generic_file_splice_read,
40 .splice_write = iter_file_splice_write,
41 .fsync = afs_fsync,
42 .lock = afs_lock,
43 .flock = afs_flock,
44};
45
46const struct inode_operations afs_file_inode_operations = {
47 .getattr = afs_getattr,
48 .setattr = afs_setattr,
49 .permission = afs_permission,
50};
51
52const struct address_space_operations afs_file_aops = {
53 .read_folio = netfs_read_folio,
54 .readahead = netfs_readahead,
55 .dirty_folio = afs_dirty_folio,
56 .launder_folio = afs_launder_folio,
57 .release_folio = afs_release_folio,
58 .invalidate_folio = afs_invalidate_folio,
59 .write_begin = afs_write_begin,
60 .write_end = afs_write_end,
61 .writepages = afs_writepages,
62 .migrate_folio = filemap_migrate_folio,
63};
64
65const struct address_space_operations afs_symlink_aops = {
66 .read_folio = afs_symlink_read_folio,
67 .release_folio = afs_release_folio,
68 .invalidate_folio = afs_invalidate_folio,
69 .migrate_folio = filemap_migrate_folio,
70};
71
72static const struct vm_operations_struct afs_vm_ops = {
73 .open = afs_vm_open,
74 .close = afs_vm_close,
75 .fault = filemap_fault,
76 .map_pages = afs_vm_map_pages,
77 .page_mkwrite = afs_page_mkwrite,
78};
79
80/*
81 * Discard a pin on a writeback key.
82 */
83void afs_put_wb_key(struct afs_wb_key *wbk)
84{
85 if (wbk && refcount_dec_and_test(&wbk->usage)) {
86 key_put(wbk->key);
87 kfree(wbk);
88 }
89}
90
91/*
92 * Cache key for writeback.
93 */
94int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
95{
96 struct afs_wb_key *wbk, *p;
97
98 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
99 if (!wbk)
100 return -ENOMEM;
101 refcount_set(&wbk->usage, 2);
102 wbk->key = af->key;
103
104 spin_lock(&vnode->wb_lock);
105 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
106 if (p->key == wbk->key)
107 goto found;
108 }
109
110 key_get(wbk->key);
111 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
112 spin_unlock(&vnode->wb_lock);
113 af->wb = wbk;
114 return 0;
115
116found:
117 refcount_inc(&p->usage);
118 spin_unlock(&vnode->wb_lock);
119 af->wb = p;
120 kfree(wbk);
121 return 0;
122}
123
124/*
125 * open an AFS file or directory and attach a key to it
126 */
127int afs_open(struct inode *inode, struct file *file)
128{
129 struct afs_vnode *vnode = AFS_FS_I(inode);
130 struct afs_file *af;
131 struct key *key;
132 int ret;
133
134 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
135
136 key = afs_request_key(vnode->volume->cell);
137 if (IS_ERR(key)) {
138 ret = PTR_ERR(key);
139 goto error;
140 }
141
142 af = kzalloc(sizeof(*af), GFP_KERNEL);
143 if (!af) {
144 ret = -ENOMEM;
145 goto error_key;
146 }
147 af->key = key;
148
149 ret = afs_validate(vnode, key);
150 if (ret < 0)
151 goto error_af;
152
153 if (file->f_mode & FMODE_WRITE) {
154 ret = afs_cache_wb_key(vnode, af);
155 if (ret < 0)
156 goto error_af;
157 }
158
159 if (file->f_flags & O_TRUNC)
160 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
161
162 fscache_use_cookie(afs_vnode_cache(vnode), file->f_mode & FMODE_WRITE);
163
164 file->private_data = af;
165 _leave(" = 0");
166 return 0;
167
168error_af:
169 kfree(af);
170error_key:
171 key_put(key);
172error:
173 _leave(" = %d", ret);
174 return ret;
175}
176
177/*
178 * release an AFS file or directory and discard its key
179 */
180int afs_release(struct inode *inode, struct file *file)
181{
182 struct afs_vnode_cache_aux aux;
183 struct afs_vnode *vnode = AFS_FS_I(inode);
184 struct afs_file *af = file->private_data;
185 loff_t i_size;
186 int ret = 0;
187
188 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
189
190 if ((file->f_mode & FMODE_WRITE))
191 ret = vfs_fsync(file, 0);
192
193 file->private_data = NULL;
194 if (af->wb)
195 afs_put_wb_key(af->wb);
196
197 if ((file->f_mode & FMODE_WRITE)) {
198 i_size = i_size_read(&vnode->netfs.inode);
199 afs_set_cache_aux(vnode, &aux);
200 fscache_unuse_cookie(afs_vnode_cache(vnode), &aux, &i_size);
201 } else {
202 fscache_unuse_cookie(afs_vnode_cache(vnode), NULL, NULL);
203 }
204
205 key_put(af->key);
206 kfree(af);
207 afs_prune_wb_keys(vnode);
208 _leave(" = %d", ret);
209 return ret;
210}
211
212/*
213 * Allocate a new read record.
214 */
215struct afs_read *afs_alloc_read(gfp_t gfp)
216{
217 struct afs_read *req;
218
219 req = kzalloc(sizeof(struct afs_read), gfp);
220 if (req)
221 refcount_set(&req->usage, 1);
222
223 return req;
224}
225
226/*
227 * Dispose of a ref to a read record.
228 */
229void afs_put_read(struct afs_read *req)
230{
231 if (refcount_dec_and_test(&req->usage)) {
232 if (req->cleanup)
233 req->cleanup(req);
234 key_put(req->key);
235 kfree(req);
236 }
237}
238
239static void afs_fetch_data_notify(struct afs_operation *op)
240{
241 struct afs_read *req = op->fetch.req;
242 struct netfs_io_subrequest *subreq = req->subreq;
243 int error = op->error;
244
245 if (error == -ECONNABORTED)
246 error = afs_abort_to_error(op->ac.abort_code);
247 req->error = error;
248
249 if (subreq) {
250 __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
251 netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
252 req->subreq = NULL;
253 } else if (req->done) {
254 req->done(req);
255 }
256}
257
258static void afs_fetch_data_success(struct afs_operation *op)
259{
260 struct afs_vnode *vnode = op->file[0].vnode;
261
262 _enter("op=%08x", op->debug_id);
263 afs_vnode_commit_status(op, &op->file[0]);
264 afs_stat_v(vnode, n_fetches);
265 atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
266 afs_fetch_data_notify(op);
267}
268
269static void afs_fetch_data_put(struct afs_operation *op)
270{
271 op->fetch.req->error = op->error;
272 afs_put_read(op->fetch.req);
273}
274
275static const struct afs_operation_ops afs_fetch_data_operation = {
276 .issue_afs_rpc = afs_fs_fetch_data,
277 .issue_yfs_rpc = yfs_fs_fetch_data,
278 .success = afs_fetch_data_success,
279 .aborted = afs_check_for_remote_deletion,
280 .failed = afs_fetch_data_notify,
281 .put = afs_fetch_data_put,
282};
283
284/*
285 * Fetch file data from the volume.
286 */
287int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
288{
289 struct afs_operation *op;
290
291 _enter("%s{%llx:%llu.%u},%x,,,",
292 vnode->volume->name,
293 vnode->fid.vid,
294 vnode->fid.vnode,
295 vnode->fid.unique,
296 key_serial(req->key));
297
298 op = afs_alloc_operation(req->key, vnode->volume);
299 if (IS_ERR(op)) {
300 if (req->subreq)
301 netfs_subreq_terminated(req->subreq, PTR_ERR(op), false);
302 return PTR_ERR(op);
303 }
304
305 afs_op_set_vnode(op, 0, vnode);
306
307 op->fetch.req = afs_get_read(req);
308 op->ops = &afs_fetch_data_operation;
309 return afs_do_sync_operation(op);
310}
311
312static void afs_issue_read(struct netfs_io_subrequest *subreq)
313{
314 struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
315 struct afs_read *fsreq;
316
317 fsreq = afs_alloc_read(GFP_NOFS);
318 if (!fsreq)
319 return netfs_subreq_terminated(subreq, -ENOMEM, false);
320
321 fsreq->subreq = subreq;
322 fsreq->pos = subreq->start + subreq->transferred;
323 fsreq->len = subreq->len - subreq->transferred;
324 fsreq->key = key_get(subreq->rreq->netfs_priv);
325 fsreq->vnode = vnode;
326 fsreq->iter = &fsreq->def_iter;
327
328 iov_iter_xarray(&fsreq->def_iter, ITER_DEST,
329 &fsreq->vnode->netfs.inode.i_mapping->i_pages,
330 fsreq->pos, fsreq->len);
331
332 afs_fetch_data(fsreq->vnode, fsreq);
333 afs_put_read(fsreq);
334}
335
336static int afs_symlink_read_folio(struct file *file, struct folio *folio)
337{
338 struct afs_vnode *vnode = AFS_FS_I(folio->mapping->host);
339 struct afs_read *fsreq;
340 int ret;
341
342 fsreq = afs_alloc_read(GFP_NOFS);
343 if (!fsreq)
344 return -ENOMEM;
345
346 fsreq->pos = folio_pos(folio);
347 fsreq->len = folio_size(folio);
348 fsreq->vnode = vnode;
349 fsreq->iter = &fsreq->def_iter;
350 iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
351 fsreq->pos, fsreq->len);
352
353 ret = afs_fetch_data(fsreq->vnode, fsreq);
354 if (ret == 0)
355 folio_mark_uptodate(folio);
356 folio_unlock(folio);
357 return ret;
358}
359
360static int afs_init_request(struct netfs_io_request *rreq, struct file *file)
361{
362 rreq->netfs_priv = key_get(afs_file_key(file));
363 return 0;
364}
365
366static int afs_begin_cache_operation(struct netfs_io_request *rreq)
367{
368#ifdef CONFIG_AFS_FSCACHE
369 struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
370
371 return fscache_begin_read_operation(&rreq->cache_resources,
372 afs_vnode_cache(vnode));
373#else
374 return -ENOBUFS;
375#endif
376}
377
378static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
379 struct folio **foliop, void **_fsdata)
380{
381 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
382
383 return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
384}
385
386static void afs_free_request(struct netfs_io_request *rreq)
387{
388 key_put(rreq->netfs_priv);
389}
390
391const struct netfs_request_ops afs_req_ops = {
392 .init_request = afs_init_request,
393 .free_request = afs_free_request,
394 .begin_cache_operation = afs_begin_cache_operation,
395 .check_write_begin = afs_check_write_begin,
396 .issue_read = afs_issue_read,
397};
398
399int afs_write_inode(struct inode *inode, struct writeback_control *wbc)
400{
401 fscache_unpin_writeback(wbc, afs_vnode_cache(AFS_FS_I(inode)));
402 return 0;
403}
404
405/*
406 * Adjust the dirty region of the page on truncation or full invalidation,
407 * getting rid of the markers altogether if the region is entirely invalidated.
408 */
409static void afs_invalidate_dirty(struct folio *folio, size_t offset,
410 size_t length)
411{
412 struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
413 unsigned long priv;
414 unsigned int f, t, end = offset + length;
415
416 priv = (unsigned long)folio_get_private(folio);
417
418 /* we clean up only if the entire page is being invalidated */
419 if (offset == 0 && length == folio_size(folio))
420 goto full_invalidate;
421
422 /* If the page was dirtied by page_mkwrite(), the PTE stays writable
423 * and we don't get another notification to tell us to expand it
424 * again.
425 */
426 if (afs_is_folio_dirty_mmapped(priv))
427 return;
428
429 /* We may need to shorten the dirty region */
430 f = afs_folio_dirty_from(folio, priv);
431 t = afs_folio_dirty_to(folio, priv);
432
433 if (t <= offset || f >= end)
434 return; /* Doesn't overlap */
435
436 if (f < offset && t > end)
437 return; /* Splits the dirty region - just absorb it */
438
439 if (f >= offset && t <= end)
440 goto undirty;
441
442 if (f < offset)
443 t = offset;
444 else
445 f = end;
446 if (f == t)
447 goto undirty;
448
449 priv = afs_folio_dirty(folio, f, t);
450 folio_change_private(folio, (void *)priv);
451 trace_afs_folio_dirty(vnode, tracepoint_string("trunc"), folio);
452 return;
453
454undirty:
455 trace_afs_folio_dirty(vnode, tracepoint_string("undirty"), folio);
456 folio_clear_dirty_for_io(folio);
457full_invalidate:
458 trace_afs_folio_dirty(vnode, tracepoint_string("inval"), folio);
459 folio_detach_private(folio);
460}
461
462/*
463 * invalidate part or all of a page
464 * - release a page and clean up its private data if offset is 0 (indicating
465 * the entire page)
466 */
467static void afs_invalidate_folio(struct folio *folio, size_t offset,
468 size_t length)
469{
470 _enter("{%lu},%zu,%zu", folio->index, offset, length);
471
472 BUG_ON(!folio_test_locked(folio));
473
474 if (folio_get_private(folio))
475 afs_invalidate_dirty(folio, offset, length);
476
477 folio_wait_fscache(folio);
478 _leave("");
479}
480
481/*
482 * release a page and clean up its private state if it's not busy
483 * - return true if the page can now be released, false if not
484 */
485static bool afs_release_folio(struct folio *folio, gfp_t gfp)
486{
487 struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio));
488
489 _enter("{{%llx:%llu}[%lu],%lx},%x",
490 vnode->fid.vid, vnode->fid.vnode, folio_index(folio), folio->flags,
491 gfp);
492
493 /* deny if folio is being written to the cache and the caller hasn't
494 * elected to wait */
495#ifdef CONFIG_AFS_FSCACHE
496 if (folio_test_fscache(folio)) {
497 if (current_is_kswapd() || !(gfp & __GFP_FS))
498 return false;
499 folio_wait_fscache(folio);
500 }
501 fscache_note_page_release(afs_vnode_cache(vnode));
502#endif
503
504 if (folio_test_private(folio)) {
505 trace_afs_folio_dirty(vnode, tracepoint_string("rel"), folio);
506 folio_detach_private(folio);
507 }
508
509 /* Indicate that the folio can be released */
510 _leave(" = T");
511 return true;
512}
513
514static void afs_add_open_mmap(struct afs_vnode *vnode)
515{
516 if (atomic_inc_return(&vnode->cb_nr_mmap) == 1) {
517 down_write(&vnode->volume->cell->fs_open_mmaps_lock);
518
519 if (list_empty(&vnode->cb_mmap_link))
520 list_add_tail(&vnode->cb_mmap_link,
521 &vnode->volume->cell->fs_open_mmaps);
522
523 up_write(&vnode->volume->cell->fs_open_mmaps_lock);
524 }
525}
526
527static void afs_drop_open_mmap(struct afs_vnode *vnode)
528{
529 if (!atomic_dec_and_test(&vnode->cb_nr_mmap))
530 return;
531
532 down_write(&vnode->volume->cell->fs_open_mmaps_lock);
533
534 if (atomic_read(&vnode->cb_nr_mmap) == 0)
535 list_del_init(&vnode->cb_mmap_link);
536
537 up_write(&vnode->volume->cell->fs_open_mmaps_lock);
538 flush_work(&vnode->cb_work);
539}
540
541/*
542 * Handle setting up a memory mapping on an AFS file.
543 */
544static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
545{
546 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
547 int ret;
548
549 afs_add_open_mmap(vnode);
550
551 ret = generic_file_mmap(file, vma);
552 if (ret == 0)
553 vma->vm_ops = &afs_vm_ops;
554 else
555 afs_drop_open_mmap(vnode);
556 return ret;
557}
558
559static void afs_vm_open(struct vm_area_struct *vma)
560{
561 afs_add_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
562}
563
564static void afs_vm_close(struct vm_area_struct *vma)
565{
566 afs_drop_open_mmap(AFS_FS_I(file_inode(vma->vm_file)));
567}
568
569static vm_fault_t afs_vm_map_pages(struct vm_fault *vmf, pgoff_t start_pgoff, pgoff_t end_pgoff)
570{
571 struct afs_vnode *vnode = AFS_FS_I(file_inode(vmf->vma->vm_file));
572 struct afs_file *af = vmf->vma->vm_file->private_data;
573
574 switch (afs_validate(vnode, af->key)) {
575 case 0:
576 return filemap_map_pages(vmf, start_pgoff, end_pgoff);
577 case -ENOMEM:
578 return VM_FAULT_OOM;
579 case -EINTR:
580 case -ERESTARTSYS:
581 return VM_FAULT_RETRY;
582 case -ESTALE:
583 default:
584 return VM_FAULT_SIGBUS;
585 }
586}
587
588static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
589{
590 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
591 struct afs_file *af = iocb->ki_filp->private_data;
592 int ret;
593
594 ret = afs_validate(vnode, af->key);
595 if (ret < 0)
596 return ret;
597
598 return generic_file_read_iter(iocb, iter);
599}