Loading...
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/netfs.h>
18#include "internal.h"
19
20static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
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);
25
26static void afs_readahead(struct readahead_control *ractl);
27static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter);
28
29const struct file_operations afs_file_operations = {
30 .open = afs_open,
31 .release = afs_release,
32 .llseek = generic_file_llseek,
33 .read_iter = afs_file_read_iter,
34 .write_iter = afs_file_write,
35 .mmap = afs_file_mmap,
36 .splice_read = generic_file_splice_read,
37 .splice_write = iter_file_splice_write,
38 .fsync = afs_fsync,
39 .lock = afs_lock,
40 .flock = afs_flock,
41};
42
43const struct inode_operations afs_file_inode_operations = {
44 .getattr = afs_getattr,
45 .setattr = afs_setattr,
46 .permission = afs_permission,
47};
48
49const struct address_space_operations afs_fs_aops = {
50 .readpage = afs_readpage,
51 .readahead = afs_readahead,
52 .set_page_dirty = afs_set_page_dirty,
53 .launder_page = afs_launder_page,
54 .releasepage = afs_releasepage,
55 .invalidatepage = afs_invalidatepage,
56 .write_begin = afs_write_begin,
57 .write_end = afs_write_end,
58 .writepage = afs_writepage,
59 .writepages = afs_writepages,
60};
61
62static const struct vm_operations_struct afs_vm_ops = {
63 .fault = filemap_fault,
64 .map_pages = filemap_map_pages,
65 .page_mkwrite = afs_page_mkwrite,
66};
67
68/*
69 * Discard a pin on a writeback key.
70 */
71void afs_put_wb_key(struct afs_wb_key *wbk)
72{
73 if (wbk && refcount_dec_and_test(&wbk->usage)) {
74 key_put(wbk->key);
75 kfree(wbk);
76 }
77}
78
79/*
80 * Cache key for writeback.
81 */
82int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
83{
84 struct afs_wb_key *wbk, *p;
85
86 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
87 if (!wbk)
88 return -ENOMEM;
89 refcount_set(&wbk->usage, 2);
90 wbk->key = af->key;
91
92 spin_lock(&vnode->wb_lock);
93 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
94 if (p->key == wbk->key)
95 goto found;
96 }
97
98 key_get(wbk->key);
99 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
100 spin_unlock(&vnode->wb_lock);
101 af->wb = wbk;
102 return 0;
103
104found:
105 refcount_inc(&p->usage);
106 spin_unlock(&vnode->wb_lock);
107 af->wb = p;
108 kfree(wbk);
109 return 0;
110}
111
112/*
113 * open an AFS file or directory and attach a key to it
114 */
115int afs_open(struct inode *inode, struct file *file)
116{
117 struct afs_vnode *vnode = AFS_FS_I(inode);
118 struct afs_file *af;
119 struct key *key;
120 int ret;
121
122 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
123
124 key = afs_request_key(vnode->volume->cell);
125 if (IS_ERR(key)) {
126 ret = PTR_ERR(key);
127 goto error;
128 }
129
130 af = kzalloc(sizeof(*af), GFP_KERNEL);
131 if (!af) {
132 ret = -ENOMEM;
133 goto error_key;
134 }
135 af->key = key;
136
137 ret = afs_validate(vnode, key);
138 if (ret < 0)
139 goto error_af;
140
141 if (file->f_mode & FMODE_WRITE) {
142 ret = afs_cache_wb_key(vnode, af);
143 if (ret < 0)
144 goto error_af;
145 }
146
147 if (file->f_flags & O_TRUNC)
148 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
149
150 file->private_data = af;
151 _leave(" = 0");
152 return 0;
153
154error_af:
155 kfree(af);
156error_key:
157 key_put(key);
158error:
159 _leave(" = %d", ret);
160 return ret;
161}
162
163/*
164 * release an AFS file or directory and discard its key
165 */
166int afs_release(struct inode *inode, struct file *file)
167{
168 struct afs_vnode *vnode = AFS_FS_I(inode);
169 struct afs_file *af = file->private_data;
170 int ret = 0;
171
172 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
173
174 if ((file->f_mode & FMODE_WRITE))
175 ret = vfs_fsync(file, 0);
176
177 file->private_data = NULL;
178 if (af->wb)
179 afs_put_wb_key(af->wb);
180 key_put(af->key);
181 kfree(af);
182 afs_prune_wb_keys(vnode);
183 _leave(" = %d", ret);
184 return ret;
185}
186
187/*
188 * Allocate a new read record.
189 */
190struct afs_read *afs_alloc_read(gfp_t gfp)
191{
192 struct afs_read *req;
193
194 req = kzalloc(sizeof(struct afs_read), gfp);
195 if (req)
196 refcount_set(&req->usage, 1);
197
198 return req;
199}
200
201/*
202 * Dispose of a ref to a read record.
203 */
204void afs_put_read(struct afs_read *req)
205{
206 if (refcount_dec_and_test(&req->usage)) {
207 if (req->cleanup)
208 req->cleanup(req);
209 key_put(req->key);
210 kfree(req);
211 }
212}
213
214static void afs_fetch_data_notify(struct afs_operation *op)
215{
216 struct afs_read *req = op->fetch.req;
217 struct netfs_read_subrequest *subreq = req->subreq;
218 int error = op->error;
219
220 if (error == -ECONNABORTED)
221 error = afs_abort_to_error(op->ac.abort_code);
222 req->error = error;
223
224 if (subreq) {
225 __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
226 netfs_subreq_terminated(subreq, error ?: req->actual_len, false);
227 req->subreq = NULL;
228 } else if (req->done) {
229 req->done(req);
230 }
231}
232
233static void afs_fetch_data_success(struct afs_operation *op)
234{
235 struct afs_vnode *vnode = op->file[0].vnode;
236
237 _enter("op=%08x", op->debug_id);
238 afs_vnode_commit_status(op, &op->file[0]);
239 afs_stat_v(vnode, n_fetches);
240 atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes);
241 afs_fetch_data_notify(op);
242}
243
244static void afs_fetch_data_put(struct afs_operation *op)
245{
246 op->fetch.req->error = op->error;
247 afs_put_read(op->fetch.req);
248}
249
250static const struct afs_operation_ops afs_fetch_data_operation = {
251 .issue_afs_rpc = afs_fs_fetch_data,
252 .issue_yfs_rpc = yfs_fs_fetch_data,
253 .success = afs_fetch_data_success,
254 .aborted = afs_check_for_remote_deletion,
255 .failed = afs_fetch_data_notify,
256 .put = afs_fetch_data_put,
257};
258
259/*
260 * Fetch file data from the volume.
261 */
262int afs_fetch_data(struct afs_vnode *vnode, struct afs_read *req)
263{
264 struct afs_operation *op;
265
266 _enter("%s{%llx:%llu.%u},%x,,,",
267 vnode->volume->name,
268 vnode->fid.vid,
269 vnode->fid.vnode,
270 vnode->fid.unique,
271 key_serial(req->key));
272
273 op = afs_alloc_operation(req->key, vnode->volume);
274 if (IS_ERR(op)) {
275 if (req->subreq)
276 netfs_subreq_terminated(req->subreq, PTR_ERR(op), false);
277 return PTR_ERR(op);
278 }
279
280 afs_op_set_vnode(op, 0, vnode);
281
282 op->fetch.req = afs_get_read(req);
283 op->ops = &afs_fetch_data_operation;
284 return afs_do_sync_operation(op);
285}
286
287static void afs_req_issue_op(struct netfs_read_subrequest *subreq)
288{
289 struct afs_vnode *vnode = AFS_FS_I(subreq->rreq->inode);
290 struct afs_read *fsreq;
291
292 fsreq = afs_alloc_read(GFP_NOFS);
293 if (!fsreq)
294 return netfs_subreq_terminated(subreq, -ENOMEM, false);
295
296 fsreq->subreq = subreq;
297 fsreq->pos = subreq->start + subreq->transferred;
298 fsreq->len = subreq->len - subreq->transferred;
299 fsreq->key = subreq->rreq->netfs_priv;
300 fsreq->vnode = vnode;
301 fsreq->iter = &fsreq->def_iter;
302
303 iov_iter_xarray(&fsreq->def_iter, READ,
304 &fsreq->vnode->vfs_inode.i_mapping->i_pages,
305 fsreq->pos, fsreq->len);
306
307 afs_fetch_data(fsreq->vnode, fsreq);
308}
309
310static int afs_symlink_readpage(struct page *page)
311{
312 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
313 struct afs_read *fsreq;
314 int ret;
315
316 fsreq = afs_alloc_read(GFP_NOFS);
317 if (!fsreq)
318 return -ENOMEM;
319
320 fsreq->pos = page->index * PAGE_SIZE;
321 fsreq->len = PAGE_SIZE;
322 fsreq->vnode = vnode;
323 fsreq->iter = &fsreq->def_iter;
324 iov_iter_xarray(&fsreq->def_iter, READ, &page->mapping->i_pages,
325 fsreq->pos, fsreq->len);
326
327 ret = afs_fetch_data(fsreq->vnode, fsreq);
328 page_endio(page, false, ret);
329 return ret;
330}
331
332static void afs_init_rreq(struct netfs_read_request *rreq, struct file *file)
333{
334 rreq->netfs_priv = key_get(afs_file_key(file));
335}
336
337static bool afs_is_cache_enabled(struct inode *inode)
338{
339 struct fscache_cookie *cookie = afs_vnode_cache(AFS_FS_I(inode));
340
341 return fscache_cookie_enabled(cookie) && !hlist_empty(&cookie->backing_objects);
342}
343
344static int afs_begin_cache_operation(struct netfs_read_request *rreq)
345{
346 struct afs_vnode *vnode = AFS_FS_I(rreq->inode);
347
348 return fscache_begin_read_operation(rreq, afs_vnode_cache(vnode));
349}
350
351static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
352 struct page *page, void **_fsdata)
353{
354 struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
355
356 return test_bit(AFS_VNODE_DELETED, &vnode->flags) ? -ESTALE : 0;
357}
358
359static void afs_priv_cleanup(struct address_space *mapping, void *netfs_priv)
360{
361 key_put(netfs_priv);
362}
363
364const struct netfs_read_request_ops afs_req_ops = {
365 .init_rreq = afs_init_rreq,
366 .is_cache_enabled = afs_is_cache_enabled,
367 .begin_cache_operation = afs_begin_cache_operation,
368 .check_write_begin = afs_check_write_begin,
369 .issue_op = afs_req_issue_op,
370 .cleanup = afs_priv_cleanup,
371};
372
373static int afs_readpage(struct file *file, struct page *page)
374{
375 if (!file)
376 return afs_symlink_readpage(page);
377
378 return netfs_readpage(file, page, &afs_req_ops, NULL);
379}
380
381static void afs_readahead(struct readahead_control *ractl)
382{
383 netfs_readahead(ractl, &afs_req_ops, NULL);
384}
385
386/*
387 * Adjust the dirty region of the page on truncation or full invalidation,
388 * getting rid of the markers altogether if the region is entirely invalidated.
389 */
390static void afs_invalidate_dirty(struct page *page, unsigned int offset,
391 unsigned int length)
392{
393 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
394 unsigned long priv;
395 unsigned int f, t, end = offset + length;
396
397 priv = page_private(page);
398
399 /* we clean up only if the entire page is being invalidated */
400 if (offset == 0 && length == thp_size(page))
401 goto full_invalidate;
402
403 /* If the page was dirtied by page_mkwrite(), the PTE stays writable
404 * and we don't get another notification to tell us to expand it
405 * again.
406 */
407 if (afs_is_page_dirty_mmapped(priv))
408 return;
409
410 /* We may need to shorten the dirty region */
411 f = afs_page_dirty_from(page, priv);
412 t = afs_page_dirty_to(page, priv);
413
414 if (t <= offset || f >= end)
415 return; /* Doesn't overlap */
416
417 if (f < offset && t > end)
418 return; /* Splits the dirty region - just absorb it */
419
420 if (f >= offset && t <= end)
421 goto undirty;
422
423 if (f < offset)
424 t = offset;
425 else
426 f = end;
427 if (f == t)
428 goto undirty;
429
430 priv = afs_page_dirty(page, f, t);
431 set_page_private(page, priv);
432 trace_afs_page_dirty(vnode, tracepoint_string("trunc"), page);
433 return;
434
435undirty:
436 trace_afs_page_dirty(vnode, tracepoint_string("undirty"), page);
437 clear_page_dirty_for_io(page);
438full_invalidate:
439 trace_afs_page_dirty(vnode, tracepoint_string("inval"), page);
440 detach_page_private(page);
441}
442
443/*
444 * invalidate part or all of a page
445 * - release a page and clean up its private data if offset is 0 (indicating
446 * the entire page)
447 */
448static void afs_invalidatepage(struct page *page, unsigned int offset,
449 unsigned int length)
450{
451 _enter("{%lu},%u,%u", page->index, offset, length);
452
453 BUG_ON(!PageLocked(page));
454
455 if (PagePrivate(page))
456 afs_invalidate_dirty(page, offset, length);
457
458 wait_on_page_fscache(page);
459 _leave("");
460}
461
462/*
463 * release a page and clean up its private state if it's not busy
464 * - return true if the page can now be released, false if not
465 */
466static int afs_releasepage(struct page *page, gfp_t gfp_flags)
467{
468 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
469
470 _enter("{{%llx:%llu}[%lu],%lx},%x",
471 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
472 gfp_flags);
473
474 /* deny if page is being written to the cache and the caller hasn't
475 * elected to wait */
476#ifdef CONFIG_AFS_FSCACHE
477 if (PageFsCache(page)) {
478 if (!(gfp_flags & __GFP_DIRECT_RECLAIM) || !(gfp_flags & __GFP_FS))
479 return false;
480 wait_on_page_fscache(page);
481 }
482#endif
483
484 if (PagePrivate(page)) {
485 trace_afs_page_dirty(vnode, tracepoint_string("rel"), page);
486 detach_page_private(page);
487 }
488
489 /* indicate that the page can be released */
490 _leave(" = T");
491 return 1;
492}
493
494/*
495 * Handle setting up a memory mapping on an AFS file.
496 */
497static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
498{
499 int ret;
500
501 ret = generic_file_mmap(file, vma);
502 if (ret == 0)
503 vma->vm_ops = &afs_vm_ops;
504 return ret;
505}
506
507static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
508{
509 struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp));
510 struct afs_file *af = iocb->ki_filp->private_data;
511 int ret;
512
513 ret = afs_validate(vnode, af->key);
514 if (ret < 0)
515 return ret;
516
517 return generic_file_read_iter(iocb, iter);
518}