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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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include "internal.h"
20
David Howells416351f2007-05-09 02:33:45 -070021static 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);
David Howells31143d52007-05-09 02:33:46 -070024static int afs_launder_page(struct page *page);
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
David Howells9b3f26c2009-04-03 16:42:41 +010026static int afs_readpages(struct file *filp, struct address_space *mapping,
27 struct list_head *pages, unsigned nr_pages);
28
David Howells00d3b7a2007-04-26 15:57:07 -070029const struct file_operations afs_file_operations = {
30 .open = afs_open,
31 .release = afs_release,
32 .llseek = generic_file_llseek,
33 .read = do_sync_read,
David Howells31143d52007-05-09 02:33:46 -070034 .write = do_sync_write,
David Howells00d3b7a2007-04-26 15:57:07 -070035 .aio_read = generic_file_aio_read,
David Howells31143d52007-05-09 02:33:46 -070036 .aio_write = afs_file_write,
David Howells00d3b7a2007-04-26 15:57:07 -070037 .mmap = generic_file_readonly_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,
Linus Torvalds1da177e2005-04-16 15:20:36 -070048};
49
Christoph Hellwigf5e54d62006-06-28 04:26:44 -070050const struct address_space_operations afs_fs_aops = {
David Howells416351f2007-05-09 02:33:45 -070051 .readpage = afs_readpage,
David Howells9b3f26c2009-04-03 16:42:41 +010052 .readpages = afs_readpages,
David Howells31143d52007-05-09 02:33:46 -070053 .set_page_dirty = afs_set_page_dirty,
54 .launder_page = afs_launder_page,
David Howells416351f2007-05-09 02:33:45 -070055 .releasepage = afs_releasepage,
56 .invalidatepage = afs_invalidatepage,
Nick Piggin15b46502008-10-15 22:04:32 -070057 .write_begin = afs_write_begin,
58 .write_end = afs_write_end,
David Howells31143d52007-05-09 02:33:46 -070059 .writepage = afs_writepage,
60 .writepages = afs_writepages,
Linus Torvalds1da177e2005-04-16 15:20:36 -070061};
62
Linus Torvalds1da177e2005-04-16 15:20:36 -070063/*
David Howells00d3b7a2007-04-26 15:57:07 -070064 * 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;
David Howells260a9802007-04-26 15:59:35 -070070 int ret;
David Howells00d3b7a2007-04-26 15:57:07 -070071
David Howells416351f2007-05-09 02:33:45 -070072 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
David Howells00d3b7a2007-04-26 15:57:07 -070073
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
David Howells260a9802007-04-26 15:59:35 -070080 ret = afs_validate(vnode, key);
81 if (ret < 0) {
82 _leave(" = %d [val]", ret);
83 return ret;
84 }
85
David Howells00d3b7a2007-04-26 15:57:07 -070086 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
David Howells416351f2007-05-09 02:33:45 -070098 _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
David Howells00d3b7a2007-04-26 15:57:07 -070099
100 key_put(file->private_data);
101 _leave(" = 0");
102 return 0;
103}
104
Matt Kraai6566abd2009-04-17 12:56:38 +0100105#ifdef CONFIG_AFS_FSCACHE
David Howells00d3b7a2007-04-26 15:57:07 -0700106/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 * deal with notification that a page was read from the cache
108 */
David Howells9b3f26c2009-04-03 16:42:41 +0100109static void afs_file_readpage_read_complete(struct page *page,
110 void *data,
111 int error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112{
David Howells9b3f26c2009-04-03 16:42:41 +0100113 _enter("%p,%p,%d", page, data, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114
David Howells9b3f26c2009-04-03 16:42:41 +0100115 /* if the read completes with an error, we just unlock the page and let
116 * the VM reissue the readpage */
117 if (!error)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 SetPageUptodate(page);
119 unlock_page(page);
David Howellsec268152007-04-26 15:49:28 -0700120}
Matt Kraai6566abd2009-04-17 12:56:38 +0100121#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123/*
David Howells416351f2007-05-09 02:33:45 -0700124 * AFS read page from file, directory or symlink
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 */
David Howells416351f2007-05-09 02:33:45 -0700126static int afs_readpage(struct file *file, struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 struct afs_vnode *vnode;
129 struct inode *inode;
David Howells00d3b7a2007-04-26 15:57:07 -0700130 struct key *key;
David Howells08e0e7c2007-04-26 15:55:03 -0700131 size_t len;
132 off_t offset;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 int ret;
134
135 inode = page->mapping->host;
136
David Howells9886e832009-08-27 13:09:06 +0100137 if (file) {
138 key = file->private_data;
139 ASSERT(key != NULL);
140 } else {
141 key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
142 if (IS_ERR(key)) {
143 ret = PTR_ERR(key);
144 goto error_nokey;
145 }
146 }
David Howells00d3b7a2007-04-26 15:57:07 -0700147
148 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149
150 vnode = AFS_FS_I(inode);
151
Matt Mackallcd7619d2005-05-01 08:59:01 -0700152 BUG_ON(!PageLocked(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
154 ret = -ESTALE;
David Howells08e0e7c2007-04-26 15:55:03 -0700155 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 goto error;
157
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 /* is it cached? */
David Howells9b3f26c2009-04-03 16:42:41 +0100159#ifdef CONFIG_AFS_FSCACHE
160 ret = fscache_read_or_alloc_page(vnode->cache,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 page,
162 afs_file_readpage_read_complete,
163 NULL,
164 GFP_KERNEL);
165#else
166 ret = -ENOBUFS;
167#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168 switch (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 /* read BIO submitted (page in cache) */
170 case 0:
171 break;
172
David Howells9b3f26c2009-04-03 16:42:41 +0100173 /* page not yet cached */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 case -ENODATA:
David Howells9b3f26c2009-04-03 16:42:41 +0100175 _debug("cache said ENODATA");
176 goto go_on;
177
178 /* page will not be cached */
179 case -ENOBUFS:
180 _debug("cache said ENOBUFS");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 default:
David Howells9b3f26c2009-04-03 16:42:41 +0100182 go_on:
David Howells08e0e7c2007-04-26 15:55:03 -0700183 offset = page->index << PAGE_CACHE_SHIFT;
184 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
186 /* read the contents of the file from the server into the
187 * page */
David Howells00d3b7a2007-04-26 15:57:07 -0700188 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 if (ret < 0) {
David Howells08e0e7c2007-04-26 15:55:03 -0700190 if (ret == -ENOENT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 _debug("got NOENT from server"
192 " - marking file deleted and stale");
David Howells08e0e7c2007-04-26 15:55:03 -0700193 set_bit(AFS_VNODE_DELETED, &vnode->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 ret = -ESTALE;
195 }
David Howells9b3f26c2009-04-03 16:42:41 +0100196
197#ifdef CONFIG_AFS_FSCACHE
198 fscache_uncache_page(vnode->cache, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199#endif
David Howells9b3f26c2009-04-03 16:42:41 +0100200 BUG_ON(PageFsCache(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 goto error;
202 }
203
204 SetPageUptodate(page);
205
David Howells9b3f26c2009-04-03 16:42:41 +0100206 /* send the page to the cache */
207#ifdef CONFIG_AFS_FSCACHE
208 if (PageFsCache(page) &&
209 fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) {
210 fscache_uncache_page(vnode->cache, page);
211 BUG_ON(PageFsCache(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213#endif
David Howells9b3f26c2009-04-03 16:42:41 +0100214 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 }
216
David Howells9886e832009-08-27 13:09:06 +0100217 if (!file)
218 key_put(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 _leave(" = 0");
220 return 0;
221
David Howells08e0e7c2007-04-26 15:55:03 -0700222error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 SetPageError(page);
224 unlock_page(page);
David Howells9886e832009-08-27 13:09:06 +0100225 if (!file)
226 key_put(key);
227error_nokey:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 _leave(" = %d", ret);
229 return ret;
David Howellsec268152007-04-26 15:49:28 -0700230}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232/*
David Howells9b3f26c2009-04-03 16:42:41 +0100233 * read a set of pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 */
David Howells9b3f26c2009-04-03 16:42:41 +0100235static int afs_readpages(struct file *file, struct address_space *mapping,
236 struct list_head *pages, unsigned nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237{
David Howells9b3f26c2009-04-03 16:42:41 +0100238 struct afs_vnode *vnode;
239 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
David Howells9b3f26c2009-04-03 16:42:41 +0100241 _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
David Howells9b3f26c2009-04-03 16:42:41 +0100243 vnode = AFS_FS_I(mapping->host);
244 if (vnode->flags & AFS_VNODE_DELETED) {
245 _leave(" = -ESTALE");
246 return -ESTALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 }
248
David Howells9b3f26c2009-04-03 16:42:41 +0100249 /* attempt to read as many of the pages as possible */
250#ifdef CONFIG_AFS_FSCACHE
251 ret = fscache_read_or_alloc_pages(vnode->cache,
252 mapping,
253 pages,
254 &nr_pages,
255 afs_file_readpage_read_complete,
256 NULL,
257 mapping_gfp_mask(mapping));
258#else
259 ret = -ENOBUFS;
260#endif
261
262 switch (ret) {
263 /* all pages are being read from the cache */
264 case 0:
265 BUG_ON(!list_empty(pages));
266 BUG_ON(nr_pages != 0);
267 _leave(" = 0 [reading all]");
268 return 0;
269
270 /* there were pages that couldn't be read from the cache */
271 case -ENODATA:
272 case -ENOBUFS:
273 break;
274
275 /* other error */
276 default:
277 _leave(" = %d", ret);
278 return ret;
279 }
280
281 /* load the missing pages from the network */
282 ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file);
283
284 _leave(" = %d [netting]", ret);
285 return ret;
David Howellsec268152007-04-26 15:49:28 -0700286}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288/*
David Howells31143d52007-05-09 02:33:46 -0700289 * write back a dirty page
290 */
291static int afs_launder_page(struct page *page)
292{
293 _enter("{%lu}", page->index);
294
295 return 0;
296}
297
298/*
David Howells9b3f26c2009-04-03 16:42:41 +0100299 * invalidate part or all of a page
300 * - release a page and clean up its private data if offset is 0 (indicating
301 * the entire page)
302 */
303static void afs_invalidatepage(struct page *page, unsigned long offset)
304{
305 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
306
307 _enter("{%lu},%lu", page->index, offset);
308
309 BUG_ON(!PageLocked(page));
310
311 /* we clean up only if the entire page is being invalidated */
312 if (offset == 0) {
313#ifdef CONFIG_AFS_FSCACHE
314 if (PageFsCache(page)) {
315 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
316 fscache_wait_on_page_write(vnode->cache, page);
317 fscache_uncache_page(vnode->cache, page);
David Howells9b3f26c2009-04-03 16:42:41 +0100318 }
319#endif
320
321 if (PagePrivate(page)) {
322 if (wb && !PageWriteback(page)) {
323 set_page_private(page, 0);
324 afs_put_writeback(wb);
325 }
326
327 if (!page_private(page))
328 ClearPagePrivate(page);
329 }
330 }
331
332 _leave("");
333}
334
335/*
336 * release a page and clean up its private state if it's not busy
337 * - return true if the page can now be released, false if not
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 */
David Howells416351f2007-05-09 02:33:45 -0700339static int afs_releasepage(struct page *page, gfp_t gfp_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340{
David Howells9b3f26c2009-04-03 16:42:41 +0100341 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
David Howells416351f2007-05-09 02:33:45 -0700342 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343
David Howells416351f2007-05-09 02:33:45 -0700344 _enter("{{%x:%u}[%lu],%lx},%x",
345 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
346 gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347
David Howells9b3f26c2009-04-03 16:42:41 +0100348 /* deny if page is being written to the cache and the caller hasn't
349 * elected to wait */
350#ifdef CONFIG_AFS_FSCACHE
David Howells201a1542009-11-19 18:11:35 +0000351 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
352 _leave(" = F [cache busy]");
353 return 0;
David Howells9b3f26c2009-04-03 16:42:41 +0100354 }
355#endif
356
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357 if (PagePrivate(page)) {
David Howells9b3f26c2009-04-03 16:42:41 +0100358 if (wb) {
359 set_page_private(page, 0);
360 afs_put_writeback(wb);
361 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 ClearPagePrivate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 }
364
David Howells9b3f26c2009-04-03 16:42:41 +0100365 /* indicate that the page can be released */
366 _leave(" = T");
367 return 1;
David Howellsec268152007-04-26 15:49:28 -0700368}