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David Howells08e0e7c2007-04-26 15:55:03 -07001/* AFS filesystem file handling
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
David Howells08e0e7c2007-04-26 15:55:03 -07003 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/fs.h>
16#include <linux/pagemap.h>
David Howells31143d52007-05-09 02:33:46 -070017#include <linux/writeback.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090018#include <linux/gfp.h>
David Howells91b467e2017-01-05 10:38:35 +000019#include <linux/task_io_accounting_ops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "internal.h"
21
David Howells1cf7a152017-11-02 15:27:52 +000022static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
David Howells416351f2007-05-09 02:33:45 -070023static int afs_readpage(struct file *file, struct page *page);
Lukas Czernerd47992f2013-05-21 23:17:23 -040024static void afs_invalidatepage(struct page *page, unsigned int offset,
25 unsigned int length);
David Howells416351f2007-05-09 02:33:45 -070026static int afs_releasepage(struct page *page, gfp_t gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
David Howells9b3f26c2009-04-03 16:42:41 +010028static int afs_readpages(struct file *filp, struct address_space *mapping,
29 struct list_head *pages, unsigned nr_pages);
30
David Howells00d3b7a2007-04-26 15:57:07 -070031const struct file_operations afs_file_operations = {
32 .open = afs_open,
33 .release = afs_release,
34 .llseek = generic_file_llseek,
Al Viroaad4f8b2014-04-02 14:33:16 -040035 .read_iter = generic_file_read_iter,
Al Viro50b55512014-04-03 14:13:46 -040036 .write_iter = afs_file_write,
David Howells1cf7a152017-11-02 15:27:52 +000037 .mmap = afs_file_mmap,
Jens Axboe5ffc4ef2007-06-01 11:49:19 +020038 .splice_read = generic_file_splice_read,
David Howells31143d52007-05-09 02:33:46 -070039 .fsync = afs_fsync,
David Howellse8d6c552007-07-15 23:40:12 -070040 .lock = afs_lock,
41 .flock = afs_flock,
David Howells00d3b7a2007-04-26 15:57:07 -070042};
43
Arjan van de Ven754661f2007-02-12 00:55:38 -080044const struct inode_operations afs_file_inode_operations = {
David Howells416351f2007-05-09 02:33:45 -070045 .getattr = afs_getattr,
David Howells31143d52007-05-09 02:33:46 -070046 .setattr = afs_setattr,
David Howells00d3b7a2007-04-26 15:57:07 -070047 .permission = afs_permission,
David Howellsd3e3b7ea2017-07-06 15:50:27 +010048 .listxattr = afs_listxattr,
Linus Torvalds1da177e2005-04-16 15:20:36 -070049};
50
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070051const struct address_space_operations afs_fs_aops = {
David Howells416351f2007-05-09 02:33:45 -070052 .readpage = afs_readpage,
David Howells9b3f26c2009-04-03 16:42:41 +010053 .readpages = afs_readpages,
David Howells31143d52007-05-09 02:33:46 -070054 .set_page_dirty = afs_set_page_dirty,
55 .launder_page = afs_launder_page,
David Howells416351f2007-05-09 02:33:45 -070056 .releasepage = afs_releasepage,
57 .invalidatepage = afs_invalidatepage,
Nick Piggin15b46502008-10-15 22:04:32 -070058 .write_begin = afs_write_begin,
59 .write_end = afs_write_end,
David Howells31143d52007-05-09 02:33:46 -070060 .writepage = afs_writepage,
61 .writepages = afs_writepages,
Linus Torvalds1da177e2005-04-16 15:20:36 -070062};
63
David Howells1cf7a152017-11-02 15:27:52 +000064static const struct vm_operations_struct afs_vm_ops = {
65 .fault = filemap_fault,
66 .map_pages = filemap_map_pages,
67 .page_mkwrite = afs_page_mkwrite,
68};
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070/*
David Howells4343d002017-11-02 15:27:52 +000071 * Discard a pin on a writeback key.
72 */
73void afs_put_wb_key(struct afs_wb_key *wbk)
74{
75 if (refcount_dec_and_test(&wbk->usage)) {
76 key_put(wbk->key);
77 kfree(wbk);
78 }
79}
80
81/*
82 * Cache key for writeback.
83 */
84int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
85{
86 struct afs_wb_key *wbk, *p;
87
88 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
89 if (!wbk)
90 return -ENOMEM;
91 refcount_set(&wbk->usage, 2);
92 wbk->key = af->key;
93
94 spin_lock(&vnode->wb_lock);
95 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
96 if (p->key == wbk->key)
97 goto found;
98 }
99
100 key_get(wbk->key);
101 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
102 spin_unlock(&vnode->wb_lock);
103 af->wb = wbk;
104 return 0;
105
106found:
107 refcount_inc(&p->usage);
108 spin_unlock(&vnode->wb_lock);
109 af->wb = p;
110 kfree(wbk);
111 return 0;
112}
113
114/*
David Howells00d3b7a2007-04-26 15:57:07 -0700115 * open an AFS file or directory and attach a key to it
116 */
117int afs_open(struct inode *inode, struct file *file)
118{
119 struct afs_vnode *vnode = AFS_FS_I(inode);
David Howells215804a2017-11-02 15:27:52 +0000120 struct afs_file *af;
David Howells00d3b7a2007-04-26 15:57:07 -0700121 struct key *key;
David Howells260a9802007-04-26 15:59:35 -0700122 int ret;
David Howells00d3b7a2007-04-26 15:57:07 -0700123
David Howells416351f2007-05-09 02:33:45 -0700124 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
David Howells00d3b7a2007-04-26 15:57:07 -0700125
126 key = afs_request_key(vnode->volume->cell);
127 if (IS_ERR(key)) {
David Howells215804a2017-11-02 15:27:52 +0000128 ret = PTR_ERR(key);
129 goto error;
130 }
131
132 af = kzalloc(sizeof(*af), GFP_KERNEL);
133 if (!af) {
134 ret = -ENOMEM;
135 goto error_key;
David Howells00d3b7a2007-04-26 15:57:07 -0700136 }
David Howells4343d002017-11-02 15:27:52 +0000137 af->key = key;
David Howells00d3b7a2007-04-26 15:57:07 -0700138
David Howells260a9802007-04-26 15:59:35 -0700139 ret = afs_validate(vnode, key);
David Howells215804a2017-11-02 15:27:52 +0000140 if (ret < 0)
141 goto error_af;
David Howells260a9802007-04-26 15:59:35 -0700142
David Howells4343d002017-11-02 15:27:52 +0000143 if (file->f_mode & FMODE_WRITE) {
144 ret = afs_cache_wb_key(vnode, af);
145 if (ret < 0)
146 goto error_af;
147 }
David Howells5a813272018-04-06 14:17:26 +0100148
149 if (file->f_flags & O_TRUNC)
150 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
David Howells4343d002017-11-02 15:27:52 +0000151
David Howells215804a2017-11-02 15:27:52 +0000152 file->private_data = af;
David Howells00d3b7a2007-04-26 15:57:07 -0700153 _leave(" = 0");
154 return 0;
David Howells215804a2017-11-02 15:27:52 +0000155
156error_af:
157 kfree(af);
158error_key:
159 key_put(key);
160error:
161 _leave(" = %d", ret);
162 return ret;
David Howells00d3b7a2007-04-26 15:57:07 -0700163}
164
165/*
166 * release an AFS file or directory and discard its key
167 */
168int afs_release(struct inode *inode, struct file *file)
169{
170 struct afs_vnode *vnode = AFS_FS_I(inode);
David Howells215804a2017-11-02 15:27:52 +0000171 struct afs_file *af = file->private_data;
David Howells00d3b7a2007-04-26 15:57:07 -0700172
David Howells416351f2007-05-09 02:33:45 -0700173 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
David Howells00d3b7a2007-04-26 15:57:07 -0700174
David Howells5a813272018-04-06 14:17:26 +0100175 if ((file->f_mode & FMODE_WRITE))
176 return vfs_fsync(file, 0);
177
David Howells215804a2017-11-02 15:27:52 +0000178 file->private_data = NULL;
David Howells4343d002017-11-02 15:27:52 +0000179 if (af->wb)
180 afs_put_wb_key(af->wb);
David Howells215804a2017-11-02 15:27:52 +0000181 key_put(af->key);
182 kfree(af);
David Howells4343d002017-11-02 15:27:52 +0000183 afs_prune_wb_keys(vnode);
David Howells00d3b7a2007-04-26 15:57:07 -0700184 _leave(" = 0");
185 return 0;
186}
187
David Howells196ee9c2017-01-05 10:38:34 +0000188/*
189 * Dispose of a ref to a read record.
190 */
191void afs_put_read(struct afs_read *req)
192{
193 int i;
194
David Howellsf3ddee82018-04-06 14:17:25 +0100195 if (refcount_dec_and_test(&req->usage)) {
David Howells196ee9c2017-01-05 10:38:34 +0000196 for (i = 0; i < req->nr_pages; i++)
197 if (req->pages[i])
198 put_page(req->pages[i]);
David Howellsf3ddee82018-04-06 14:17:25 +0100199 if (req->pages != req->array)
200 kfree(req->pages);
David Howells196ee9c2017-01-05 10:38:34 +0000201 kfree(req);
202 }
203}
204
Matt Kraai6566abd2009-04-17 12:56:38 +0100205#ifdef CONFIG_AFS_FSCACHE
David Howells00d3b7a2007-04-26 15:57:07 -0700206/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 * deal with notification that a page was read from the cache
208 */
David Howells9b3f26c2009-04-03 16:42:41 +0100209static void afs_file_readpage_read_complete(struct page *page,
210 void *data,
211 int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212{
David Howells9b3f26c2009-04-03 16:42:41 +0100213 _enter("%p,%p,%d", page, data, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214
David Howells9b3f26c2009-04-03 16:42:41 +0100215 /* if the read completes with an error, we just unlock the page and let
216 * the VM reissue the readpage */
217 if (!error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 SetPageUptodate(page);
219 unlock_page(page);
David Howellsec268152007-04-26 15:49:28 -0700220}
Matt Kraai6566abd2009-04-17 12:56:38 +0100221#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223/*
David Howellsd2ddc772017-11-02 15:27:50 +0000224 * Fetch file data from the volume.
225 */
226int afs_fetch_data(struct afs_vnode *vnode, struct key *key, struct afs_read *desc)
227{
228 struct afs_fs_cursor fc;
229 int ret;
230
231 _enter("%s{%x:%u.%u},%x,,,",
232 vnode->volume->name,
233 vnode->fid.vid,
234 vnode->fid.vnode,
235 vnode->fid.unique,
236 key_serial(key));
237
238 ret = -ERESTARTSYS;
239 if (afs_begin_vnode_operation(&fc, vnode, key)) {
240 while (afs_select_fileserver(&fc)) {
David Howells68251f02018-05-12 22:31:33 +0100241 fc.cb_break = afs_calc_vnode_cb_break(vnode);
David Howellsd2ddc772017-11-02 15:27:50 +0000242 afs_fs_fetch_data(&fc, desc);
243 }
244
245 afs_check_for_remote_deletion(&fc, fc.vnode);
246 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
247 ret = afs_end_vnode_operation(&fc);
248 }
249
David Howells76a5cb62018-04-06 14:17:26 +0100250 if (ret == 0) {
251 afs_stat_v(vnode, n_fetches);
252 atomic_long_add(desc->actual_len,
253 &afs_v2net(vnode)->n_fetch_bytes);
254 }
255
David Howellsd2ddc772017-11-02 15:27:50 +0000256 _leave(" = %d", ret);
257 return ret;
258}
259
260/*
Al Virof6d335c2010-05-21 15:27:09 +0100261 * read page from file, directory or symlink, given a key to use
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 */
Al Virof6d335c2010-05-21 15:27:09 +0100263int afs_page_filler(void *data, struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264{
Al Virof6d335c2010-05-21 15:27:09 +0100265 struct inode *inode = page->mapping->host;
266 struct afs_vnode *vnode = AFS_FS_I(inode);
David Howells196ee9c2017-01-05 10:38:34 +0000267 struct afs_read *req;
Al Virof6d335c2010-05-21 15:27:09 +0100268 struct key *key = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 int ret;
270
David Howells00d3b7a2007-04-26 15:57:07 -0700271 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
Matt Mackallcd7619d2005-05-01 08:59:01 -0700273 BUG_ON(!PageLocked(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275 ret = -ESTALE;
David Howells08e0e7c2007-04-26 15:55:03 -0700276 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 goto error;
278
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 /* is it cached? */
David Howells9b3f26c2009-04-03 16:42:41 +0100280#ifdef CONFIG_AFS_FSCACHE
281 ret = fscache_read_or_alloc_page(vnode->cache,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 page,
283 afs_file_readpage_read_complete,
284 NULL,
285 GFP_KERNEL);
286#else
287 ret = -ENOBUFS;
288#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 switch (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 /* read BIO submitted (page in cache) */
291 case 0:
292 break;
293
David Howells9b3f26c2009-04-03 16:42:41 +0100294 /* page not yet cached */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 case -ENODATA:
David Howells9b3f26c2009-04-03 16:42:41 +0100296 _debug("cache said ENODATA");
297 goto go_on;
298
299 /* page will not be cached */
300 case -ENOBUFS:
301 _debug("cache said ENOBUFS");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 default:
David Howells9b3f26c2009-04-03 16:42:41 +0100303 go_on:
David Howells196ee9c2017-01-05 10:38:34 +0000304 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
305 GFP_KERNEL);
306 if (!req)
307 goto enomem;
308
David Howells6db3ac32017-03-16 16:27:44 +0000309 /* We request a full page. If the page is a partial one at the
310 * end of the file, the server will return a short read and the
311 * unmarshalling code will clear the unfilled space.
312 */
David Howellsf3ddee82018-04-06 14:17:25 +0100313 refcount_set(&req->usage, 1);
David Howells196ee9c2017-01-05 10:38:34 +0000314 req->pos = (loff_t)page->index << PAGE_SHIFT;
David Howells6db3ac32017-03-16 16:27:44 +0000315 req->len = PAGE_SIZE;
David Howells196ee9c2017-01-05 10:38:34 +0000316 req->nr_pages = 1;
David Howellsf3ddee82018-04-06 14:17:25 +0100317 req->pages = req->array;
David Howells196ee9c2017-01-05 10:38:34 +0000318 req->pages[0] = page;
319 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320
321 /* read the contents of the file from the server into the
322 * page */
David Howellsd2ddc772017-11-02 15:27:50 +0000323 ret = afs_fetch_data(vnode, key, req);
David Howells196ee9c2017-01-05 10:38:34 +0000324 afs_put_read(req);
David Howellsdab17c12017-11-02 15:27:52 +0000325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 if (ret < 0) {
David Howells08e0e7c2007-04-26 15:55:03 -0700327 if (ret == -ENOENT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 _debug("got NOENT from server"
329 " - marking file deleted and stale");
David Howells08e0e7c2007-04-26 15:55:03 -0700330 set_bit(AFS_VNODE_DELETED, &vnode->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 ret = -ESTALE;
332 }
David Howells9b3f26c2009-04-03 16:42:41 +0100333
334#ifdef CONFIG_AFS_FSCACHE
335 fscache_uncache_page(vnode->cache, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336#endif
David Howells9b3f26c2009-04-03 16:42:41 +0100337 BUG_ON(PageFsCache(page));
David Howells68ae8492017-03-16 16:27:48 +0000338
339 if (ret == -EINTR ||
340 ret == -ENOMEM ||
341 ret == -ERESTARTSYS ||
342 ret == -EAGAIN)
343 goto error;
344 goto io_error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 }
346
347 SetPageUptodate(page);
348
David Howells9b3f26c2009-04-03 16:42:41 +0100349 /* send the page to the cache */
350#ifdef CONFIG_AFS_FSCACHE
351 if (PageFsCache(page) &&
David Howellsee1235a2018-04-04 13:41:28 +0100352 fscache_write_page(vnode->cache, page, vnode->status.size,
353 GFP_KERNEL) != 0) {
David Howells9b3f26c2009-04-03 16:42:41 +0100354 fscache_uncache_page(vnode->cache, page);
355 BUG_ON(PageFsCache(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357#endif
David Howells9b3f26c2009-04-03 16:42:41 +0100358 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 }
360
361 _leave(" = 0");
362 return 0;
363
David Howells68ae8492017-03-16 16:27:48 +0000364io_error:
365 SetPageError(page);
366 goto error;
David Howells196ee9c2017-01-05 10:38:34 +0000367enomem:
368 ret = -ENOMEM;
David Howells08e0e7c2007-04-26 15:55:03 -0700369error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 _leave(" = %d", ret);
372 return ret;
David Howellsec268152007-04-26 15:49:28 -0700373}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375/*
Al Virof6d335c2010-05-21 15:27:09 +0100376 * read page from file, directory or symlink, given a file to nominate the key
377 * to be used
378 */
379static int afs_readpage(struct file *file, struct page *page)
380{
381 struct key *key;
382 int ret;
383
384 if (file) {
David Howells215804a2017-11-02 15:27:52 +0000385 key = afs_file_key(file);
Al Virof6d335c2010-05-21 15:27:09 +0100386 ASSERT(key != NULL);
387 ret = afs_page_filler(key, page);
388 } else {
389 struct inode *inode = page->mapping->host;
David Howellsd2ddc772017-11-02 15:27:50 +0000390 key = afs_request_key(AFS_FS_S(inode->i_sb)->cell);
Al Virof6d335c2010-05-21 15:27:09 +0100391 if (IS_ERR(key)) {
392 ret = PTR_ERR(key);
393 } else {
394 ret = afs_page_filler(key, page);
395 key_put(key);
396 }
397 }
398 return ret;
399}
400
401/*
David Howells91b467e2017-01-05 10:38:35 +0000402 * Make pages available as they're filled.
403 */
404static void afs_readpages_page_done(struct afs_call *call, struct afs_read *req)
405{
Arnd Bergmann51c89e62017-01-13 14:46:19 +0000406#ifdef CONFIG_AFS_FSCACHE
David Howells97e30432017-11-02 15:27:48 +0000407 struct afs_vnode *vnode = call->reply[0];
Arnd Bergmann51c89e62017-01-13 14:46:19 +0000408#endif
David Howells91b467e2017-01-05 10:38:35 +0000409 struct page *page = req->pages[req->index];
410
411 req->pages[req->index] = NULL;
412 SetPageUptodate(page);
413
414 /* send the page to the cache */
415#ifdef CONFIG_AFS_FSCACHE
416 if (PageFsCache(page) &&
David Howellsee1235a2018-04-04 13:41:28 +0100417 fscache_write_page(vnode->cache, page, vnode->status.size,
418 GFP_KERNEL) != 0) {
David Howells91b467e2017-01-05 10:38:35 +0000419 fscache_uncache_page(vnode->cache, page);
420 BUG_ON(PageFsCache(page));
421 }
422#endif
423 unlock_page(page);
424 put_page(page);
425}
426
427/*
428 * Read a contiguous set of pages.
429 */
430static int afs_readpages_one(struct file *file, struct address_space *mapping,
431 struct list_head *pages)
432{
433 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
434 struct afs_read *req;
435 struct list_head *p;
436 struct page *first, *page;
David Howells215804a2017-11-02 15:27:52 +0000437 struct key *key = afs_file_key(file);
David Howells91b467e2017-01-05 10:38:35 +0000438 pgoff_t index;
439 int ret, n, i;
440
441 /* Count the number of contiguous pages at the front of the list. Note
442 * that the list goes prev-wards rather than next-wards.
443 */
444 first = list_entry(pages->prev, struct page, lru);
445 index = first->index + 1;
446 n = 1;
447 for (p = first->lru.prev; p != pages; p = p->prev) {
448 page = list_entry(p, struct page, lru);
449 if (page->index != index)
450 break;
451 index++;
452 n++;
453 }
454
455 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n,
456 GFP_NOFS);
457 if (!req)
458 return -ENOMEM;
459
David Howellsf3ddee82018-04-06 14:17:25 +0100460 refcount_set(&req->usage, 1);
David Howells91b467e2017-01-05 10:38:35 +0000461 req->page_done = afs_readpages_page_done;
462 req->pos = first->index;
463 req->pos <<= PAGE_SHIFT;
David Howellsf3ddee82018-04-06 14:17:25 +0100464 req->pages = req->array;
David Howells91b467e2017-01-05 10:38:35 +0000465
466 /* Transfer the pages to the request. We add them in until one fails
467 * to add to the LRU and then we stop (as that'll make a hole in the
468 * contiguous run.
469 *
470 * Note that it's possible for the file size to change whilst we're
471 * doing this, but we rely on the server returning less than we asked
472 * for if the file shrank. We also rely on this to deal with a partial
473 * page at the end of the file.
474 */
475 do {
476 page = list_entry(pages->prev, struct page, lru);
477 list_del(&page->lru);
478 index = page->index;
479 if (add_to_page_cache_lru(page, mapping, index,
480 readahead_gfp_mask(mapping))) {
481#ifdef CONFIG_AFS_FSCACHE
482 fscache_uncache_page(vnode->cache, page);
483#endif
484 put_page(page);
485 break;
486 }
487
488 req->pages[req->nr_pages++] = page;
489 req->len += PAGE_SIZE;
490 } while (req->nr_pages < n);
491
492 if (req->nr_pages == 0) {
493 kfree(req);
494 return 0;
495 }
496
David Howellsd2ddc772017-11-02 15:27:50 +0000497 ret = afs_fetch_data(vnode, key, req);
David Howells91b467e2017-01-05 10:38:35 +0000498 if (ret < 0)
499 goto error;
500
501 task_io_account_read(PAGE_SIZE * req->nr_pages);
502 afs_put_read(req);
503 return 0;
504
505error:
506 if (ret == -ENOENT) {
507 _debug("got NOENT from server"
508 " - marking file deleted and stale");
509 set_bit(AFS_VNODE_DELETED, &vnode->flags);
510 ret = -ESTALE;
511 }
512
513 for (i = 0; i < req->nr_pages; i++) {
514 page = req->pages[i];
515 if (page) {
516#ifdef CONFIG_AFS_FSCACHE
517 fscache_uncache_page(vnode->cache, page);
518#endif
519 SetPageError(page);
520 unlock_page(page);
521 }
522 }
523
524 afs_put_read(req);
525 return ret;
526}
527
528/*
David Howells9b3f26c2009-04-03 16:42:41 +0100529 * read a set of pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 */
David Howells9b3f26c2009-04-03 16:42:41 +0100531static int afs_readpages(struct file *file, struct address_space *mapping,
532 struct list_head *pages, unsigned nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533{
David Howells215804a2017-11-02 15:27:52 +0000534 struct key *key = afs_file_key(file);
David Howells9b3f26c2009-04-03 16:42:41 +0100535 struct afs_vnode *vnode;
536 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537
Al Virof6d335c2010-05-21 15:27:09 +0100538 _enter("{%d},{%lu},,%d",
539 key_serial(key), mapping->host->i_ino, nr_pages);
540
541 ASSERT(key != NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542
David Howells9b3f26c2009-04-03 16:42:41 +0100543 vnode = AFS_FS_I(mapping->host);
Dan Carpenterad2a8e62012-03-20 16:58:06 +0000544 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
David Howells9b3f26c2009-04-03 16:42:41 +0100545 _leave(" = -ESTALE");
546 return -ESTALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 }
548
David Howells9b3f26c2009-04-03 16:42:41 +0100549 /* attempt to read as many of the pages as possible */
550#ifdef CONFIG_AFS_FSCACHE
551 ret = fscache_read_or_alloc_pages(vnode->cache,
552 mapping,
553 pages,
554 &nr_pages,
555 afs_file_readpage_read_complete,
556 NULL,
557 mapping_gfp_mask(mapping));
558#else
559 ret = -ENOBUFS;
560#endif
561
562 switch (ret) {
563 /* all pages are being read from the cache */
564 case 0:
565 BUG_ON(!list_empty(pages));
566 BUG_ON(nr_pages != 0);
567 _leave(" = 0 [reading all]");
568 return 0;
569
570 /* there were pages that couldn't be read from the cache */
571 case -ENODATA:
572 case -ENOBUFS:
573 break;
574
575 /* other error */
576 default:
577 _leave(" = %d", ret);
578 return ret;
579 }
580
David Howells91b467e2017-01-05 10:38:35 +0000581 while (!list_empty(pages)) {
582 ret = afs_readpages_one(file, mapping, pages);
583 if (ret < 0)
584 break;
585 }
David Howells9b3f26c2009-04-03 16:42:41 +0100586
587 _leave(" = %d [netting]", ret);
588 return ret;
David Howellsec268152007-04-26 15:49:28 -0700589}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591/*
David Howells9b3f26c2009-04-03 16:42:41 +0100592 * invalidate part or all of a page
593 * - release a page and clean up its private data if offset is 0 (indicating
594 * the entire page)
595 */
Lukas Czernerd47992f2013-05-21 23:17:23 -0400596static void afs_invalidatepage(struct page *page, unsigned int offset,
597 unsigned int length)
David Howells9b3f26c2009-04-03 16:42:41 +0100598{
David Howells13524ab2017-11-02 15:27:53 +0000599 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
600 unsigned long priv;
601
Lukas Czernerd47992f2013-05-21 23:17:23 -0400602 _enter("{%lu},%u,%u", page->index, offset, length);
David Howells9b3f26c2009-04-03 16:42:41 +0100603
604 BUG_ON(!PageLocked(page));
605
606 /* we clean up only if the entire page is being invalidated */
Kirill A. Shutemov09cbfea2016-04-01 15:29:47 +0300607 if (offset == 0 && length == PAGE_SIZE) {
David Howells9b3f26c2009-04-03 16:42:41 +0100608#ifdef CONFIG_AFS_FSCACHE
609 if (PageFsCache(page)) {
610 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
611 fscache_wait_on_page_write(vnode->cache, page);
612 fscache_uncache_page(vnode->cache, page);
David Howells9b3f26c2009-04-03 16:42:41 +0100613 }
614#endif
615
616 if (PagePrivate(page)) {
David Howells13524ab2017-11-02 15:27:53 +0000617 priv = page_private(page);
618 trace_afs_page_dirty(vnode, tracepoint_string("inval"),
619 page->index, priv);
David Howells4343d002017-11-02 15:27:52 +0000620 set_page_private(page, 0);
621 ClearPagePrivate(page);
David Howells9b3f26c2009-04-03 16:42:41 +0100622 }
623 }
624
625 _leave("");
626}
627
628/*
629 * release a page and clean up its private state if it's not busy
630 * - return true if the page can now be released, false if not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 */
David Howells416351f2007-05-09 02:33:45 -0700632static int afs_releasepage(struct page *page, gfp_t gfp_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633{
David Howells416351f2007-05-09 02:33:45 -0700634 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
David Howells13524ab2017-11-02 15:27:53 +0000635 unsigned long priv;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636
David Howells416351f2007-05-09 02:33:45 -0700637 _enter("{{%x:%u}[%lu],%lx},%x",
638 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
639 gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640
David Howells9b3f26c2009-04-03 16:42:41 +0100641 /* deny if page is being written to the cache and the caller hasn't
642 * elected to wait */
643#ifdef CONFIG_AFS_FSCACHE
David Howells201a1542009-11-19 18:11:35 +0000644 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
645 _leave(" = F [cache busy]");
646 return 0;
David Howells9b3f26c2009-04-03 16:42:41 +0100647 }
648#endif
649
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if (PagePrivate(page)) {
David Howells13524ab2017-11-02 15:27:53 +0000651 priv = page_private(page);
652 trace_afs_page_dirty(vnode, tracepoint_string("rel"),
653 page->index, priv);
David Howells4343d002017-11-02 15:27:52 +0000654 set_page_private(page, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 ClearPagePrivate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 }
657
David Howells9b3f26c2009-04-03 16:42:41 +0100658 /* indicate that the page can be released */
659 _leave(" = T");
660 return 1;
David Howellsec268152007-04-26 15:49:28 -0700661}
David Howells1cf7a152017-11-02 15:27:52 +0000662
663/*
664 * Handle setting up a memory mapping on an AFS file.
665 */
666static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
667{
668 int ret;
669
670 ret = generic_file_mmap(file, vma);
671 if (ret == 0)
672 vma->vm_ops = &afs_vm_ops;
673 return ret;
674}