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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/*
Al Virof6d335c2010-05-21 15:27:09 +0100124 * read page from file, directory or symlink, given a key to use
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 */
Al Virof6d335c2010-05-21 15:27:09 +0100126int afs_page_filler(void *data, struct page *page)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127{
Al Virof6d335c2010-05-21 15:27:09 +0100128 struct inode *inode = page->mapping->host;
129 struct afs_vnode *vnode = AFS_FS_I(inode);
130 struct key *key = data;
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
David Howells00d3b7a2007-04-26 15:57:07 -0700135 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Matt Mackallcd7619d2005-05-01 08:59:01 -0700137 BUG_ON(!PageLocked(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
139 ret = -ESTALE;
David Howells08e0e7c2007-04-26 15:55:03 -0700140 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 goto error;
142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 /* is it cached? */
David Howells9b3f26c2009-04-03 16:42:41 +0100144#ifdef CONFIG_AFS_FSCACHE
145 ret = fscache_read_or_alloc_page(vnode->cache,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 page,
147 afs_file_readpage_read_complete,
148 NULL,
149 GFP_KERNEL);
150#else
151 ret = -ENOBUFS;
152#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 switch (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 /* read BIO submitted (page in cache) */
155 case 0:
156 break;
157
David Howells9b3f26c2009-04-03 16:42:41 +0100158 /* page not yet cached */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 case -ENODATA:
David Howells9b3f26c2009-04-03 16:42:41 +0100160 _debug("cache said ENODATA");
161 goto go_on;
162
163 /* page will not be cached */
164 case -ENOBUFS:
165 _debug("cache said ENOBUFS");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 default:
David Howells9b3f26c2009-04-03 16:42:41 +0100167 go_on:
David Howells08e0e7c2007-04-26 15:55:03 -0700168 offset = page->index << PAGE_CACHE_SHIFT;
169 len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170
171 /* read the contents of the file from the server into the
172 * page */
David Howells00d3b7a2007-04-26 15:57:07 -0700173 ret = afs_vnode_fetch_data(vnode, key, offset, len, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 if (ret < 0) {
David Howells08e0e7c2007-04-26 15:55:03 -0700175 if (ret == -ENOENT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 _debug("got NOENT from server"
177 " - marking file deleted and stale");
David Howells08e0e7c2007-04-26 15:55:03 -0700178 set_bit(AFS_VNODE_DELETED, &vnode->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 ret = -ESTALE;
180 }
David Howells9b3f26c2009-04-03 16:42:41 +0100181
182#ifdef CONFIG_AFS_FSCACHE
183 fscache_uncache_page(vnode->cache, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184#endif
David Howells9b3f26c2009-04-03 16:42:41 +0100185 BUG_ON(PageFsCache(page));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 goto error;
187 }
188
189 SetPageUptodate(page);
190
David Howells9b3f26c2009-04-03 16:42:41 +0100191 /* 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));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198#endif
David Howells9b3f26c2009-04-03 16:42:41 +0100199 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 }
201
202 _leave(" = 0");
203 return 0;
204
David Howells08e0e7c2007-04-26 15:55:03 -0700205error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 SetPageError(page);
207 unlock_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 _leave(" = %d", ret);
209 return ret;
David Howellsec268152007-04-26 15:49:28 -0700210}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212/*
Al Virof6d335c2010-05-21 15:27:09 +0100213 * 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/*
David Howells9b3f26c2009-04-03 16:42:41 +0100239 * read a set of pages
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 */
David Howells9b3f26c2009-04-03 16:42:41 +0100241static int afs_readpages(struct file *file, struct address_space *mapping,
242 struct list_head *pages, unsigned nr_pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243{
Al Virof6d335c2010-05-21 15:27:09 +0100244 struct key *key = file->private_data;
David Howells9b3f26c2009-04-03 16:42:41 +0100245 struct afs_vnode *vnode;
246 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247
Al Virof6d335c2010-05-21 15:27:09 +0100248 _enter("{%d},{%lu},,%d",
249 key_serial(key), mapping->host->i_ino, nr_pages);
250
251 ASSERT(key != NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
David Howells9b3f26c2009-04-03 16:42:41 +0100253 vnode = AFS_FS_I(mapping->host);
Dan Carpenterad2a8e62012-03-20 16:58:06 +0000254 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
David Howells9b3f26c2009-04-03 16:42:41 +0100255 _leave(" = -ESTALE");
256 return -ESTALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 }
258
David Howells9b3f26c2009-04-03 16:42:41 +0100259 /* 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 */
Al Virof6d335c2010-05-21 15:27:09 +0100292 ret = read_cache_pages(mapping, pages, afs_page_filler, key);
David Howells9b3f26c2009-04-03 16:42:41 +0100293
294 _leave(" = %d [netting]", ret);
295 return ret;
David Howellsec268152007-04-26 15:49:28 -0700296}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298/*
David Howells31143d52007-05-09 02:33:46 -0700299 * 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/*
David Howells9b3f26c2009-04-03 16:42:41 +0100309 * 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);
David Howells9b3f26c2009-04-03 16:42:41 +0100328 }
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 */
David Howells416351f2007-05-09 02:33:45 -0700349static int afs_releasepage(struct page *page, gfp_t gfp_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350{
David Howells9b3f26c2009-04-03 16:42:41 +0100351 struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
David Howells416351f2007-05-09 02:33:45 -0700352 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353
David Howells416351f2007-05-09 02:33:45 -0700354 _enter("{{%x:%u}[%lu],%lx},%x",
355 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
356 gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357
David Howells9b3f26c2009-04-03 16:42:41 +0100358 /* deny if page is being written to the cache and the caller hasn't
359 * elected to wait */
360#ifdef CONFIG_AFS_FSCACHE
David Howells201a1542009-11-19 18:11:35 +0000361 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
362 _leave(" = F [cache busy]");
363 return 0;
David Howells9b3f26c2009-04-03 16:42:41 +0100364 }
365#endif
366
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 if (PagePrivate(page)) {
David Howells9b3f26c2009-04-03 16:42:41 +0100368 if (wb) {
369 set_page_private(page, 0);
370 afs_put_writeback(wb);
371 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 ClearPagePrivate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 }
374
David Howells9b3f26c2009-04-03 16:42:41 +0100375 /* indicate that the page can be released */
376 _leave(" = T");
377 return 1;
David Howellsec268152007-04-26 15:49:28 -0700378}