1 /* AFS filesystem file handling
3 * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
16 #include <linux/pagemap.h>
17 #include <linux/writeback.h>
18 #include <linux/gfp.h>
19 #include <linux/task_io_accounting_ops.h>
23 static int afs_file_mmap(struct file *file, struct vm_area_struct *vma);
24 static int afs_readpage(struct file *file, struct page *page);
25 static void afs_invalidatepage(struct page *page, unsigned int offset,
27 static int afs_releasepage(struct page *page, gfp_t gfp_flags);
29 static int afs_readpages(struct file *filp, struct address_space *mapping,
30 struct list_head *pages, unsigned nr_pages);
32 const struct file_operations afs_file_operations = {
34 .release = afs_release,
35 .llseek = generic_file_llseek,
36 .read_iter = generic_file_read_iter,
37 .write_iter = afs_file_write,
38 .mmap = afs_file_mmap,
39 .splice_read = generic_file_splice_read,
45 const struct inode_operations afs_file_inode_operations = {
46 .getattr = afs_getattr,
47 .setattr = afs_setattr,
48 .permission = afs_permission,
49 .listxattr = afs_listxattr,
52 const struct address_space_operations afs_fs_aops = {
53 .readpage = afs_readpage,
54 .readpages = afs_readpages,
55 .set_page_dirty = afs_set_page_dirty,
56 .launder_page = afs_launder_page,
57 .releasepage = afs_releasepage,
58 .invalidatepage = afs_invalidatepage,
59 .write_begin = afs_write_begin,
60 .write_end = afs_write_end,
61 .writepage = afs_writepage,
62 .writepages = afs_writepages,
65 static const struct vm_operations_struct afs_vm_ops = {
66 .fault = filemap_fault,
67 .map_pages = filemap_map_pages,
68 .page_mkwrite = afs_page_mkwrite,
72 * Discard a pin on a writeback key.
74 void afs_put_wb_key(struct afs_wb_key *wbk)
76 if (refcount_dec_and_test(&wbk->usage)) {
83 * Cache key for writeback.
85 int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
87 struct afs_wb_key *wbk, *p;
89 wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
92 refcount_set(&wbk->usage, 2);
95 spin_lock(&vnode->wb_lock);
96 list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
97 if (p->key == wbk->key)
102 list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
103 spin_unlock(&vnode->wb_lock);
108 refcount_inc(&p->usage);
109 spin_unlock(&vnode->wb_lock);
116 * open an AFS file or directory and attach a key to it
118 int afs_open(struct inode *inode, struct file *file)
120 struct afs_vnode *vnode = AFS_FS_I(inode);
125 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
127 key = afs_request_key(vnode->volume->cell);
133 af = kzalloc(sizeof(*af), GFP_KERNEL);
140 ret = afs_validate(vnode, key);
144 if (file->f_mode & FMODE_WRITE) {
145 ret = afs_cache_wb_key(vnode, af);
150 if (file->f_flags & O_TRUNC)
151 set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags);
153 file->private_data = af;
162 _leave(" = %d", ret);
167 * release an AFS file or directory and discard its key
169 int afs_release(struct inode *inode, struct file *file)
171 struct afs_vnode *vnode = AFS_FS_I(inode);
172 struct afs_file *af = file->private_data;
175 _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode);
177 if ((file->f_mode & FMODE_WRITE))
178 ret = vfs_fsync(file, 0);
180 file->private_data = NULL;
182 afs_put_wb_key(af->wb);
185 afs_prune_wb_keys(vnode);
186 _leave(" = %d", ret);
191 * Dispose of a ref to a read record.
193 void afs_put_read(struct afs_read *req)
197 if (refcount_dec_and_test(&req->usage)) {
198 for (i = 0; i < req->nr_pages; i++)
200 put_page(req->pages[i]);
201 if (req->pages != req->array)
207 #ifdef CONFIG_AFS_FSCACHE
209 * deal with notification that a page was read from the cache
211 static void afs_file_readpage_read_complete(struct page *page,
215 _enter("%p,%p,%d", page, data, error);
217 /* if the read completes with an error, we just unlock the page and let
218 * the VM reissue the readpage */
220 SetPageUptodate(page);
226 * Fetch file data from the volume.
228 int afs_fetch_data(struct afs_vnode *vnode, struct key *key, struct afs_read *desc)
230 struct afs_fs_cursor fc;
233 _enter("%s{%llx:%llu.%u},%x,,,",
241 if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
242 while (afs_select_fileserver(&fc)) {
243 fc.cb_break = afs_calc_vnode_cb_break(vnode);
244 afs_fs_fetch_data(&fc, desc);
247 afs_check_for_remote_deletion(&fc, fc.vnode);
248 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
249 ret = afs_end_vnode_operation(&fc);
253 afs_stat_v(vnode, n_fetches);
254 atomic_long_add(desc->actual_len,
255 &afs_v2net(vnode)->n_fetch_bytes);
258 _leave(" = %d", ret);
263 * read page from file, directory or symlink, given a key to use
265 int afs_page_filler(void *data, struct page *page)
267 struct inode *inode = page->mapping->host;
268 struct afs_vnode *vnode = AFS_FS_I(inode);
269 struct afs_read *req;
270 struct key *key = data;
273 _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
275 BUG_ON(!PageLocked(page));
278 if (test_bit(AFS_VNODE_DELETED, &vnode->flags))
282 #ifdef CONFIG_AFS_FSCACHE
283 ret = fscache_read_or_alloc_page(vnode->cache,
285 afs_file_readpage_read_complete,
292 /* read BIO submitted (page in cache) */
296 /* page not yet cached */
298 _debug("cache said ENODATA");
301 /* page will not be cached */
303 _debug("cache said ENOBUFS");
308 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *),
313 /* We request a full page. If the page is a partial one at the
314 * end of the file, the server will return a short read and the
315 * unmarshalling code will clear the unfilled space.
317 refcount_set(&req->usage, 1);
318 req->pos = (loff_t)page->index << PAGE_SHIFT;
319 req->len = PAGE_SIZE;
321 req->pages = req->array;
322 req->pages[0] = page;
325 /* read the contents of the file from the server into the
327 ret = afs_fetch_data(vnode, key, req);
331 if (ret == -ENOENT) {
332 _debug("got NOENT from server"
333 " - marking file deleted and stale");
334 set_bit(AFS_VNODE_DELETED, &vnode->flags);
338 #ifdef CONFIG_AFS_FSCACHE
339 fscache_uncache_page(vnode->cache, page);
341 BUG_ON(PageFsCache(page));
345 ret == -ERESTARTSYS ||
351 SetPageUptodate(page);
353 /* send the page to the cache */
354 #ifdef CONFIG_AFS_FSCACHE
355 if (PageFsCache(page) &&
356 fscache_write_page(vnode->cache, page, vnode->status.size,
358 fscache_uncache_page(vnode->cache, page);
359 BUG_ON(PageFsCache(page));
375 _leave(" = %d", ret);
380 * read page from file, directory or symlink, given a file to nominate the key
383 static int afs_readpage(struct file *file, struct page *page)
389 key = afs_file_key(file);
391 ret = afs_page_filler(key, page);
393 struct inode *inode = page->mapping->host;
394 key = afs_request_key(AFS_FS_S(inode->i_sb)->cell);
398 ret = afs_page_filler(key, page);
406 * Make pages available as they're filled.
408 static void afs_readpages_page_done(struct afs_call *call, struct afs_read *req)
410 #ifdef CONFIG_AFS_FSCACHE
411 struct afs_vnode *vnode = call->xvnode;
413 struct page *page = req->pages[req->index];
415 req->pages[req->index] = NULL;
416 SetPageUptodate(page);
418 /* send the page to the cache */
419 #ifdef CONFIG_AFS_FSCACHE
420 if (PageFsCache(page) &&
421 fscache_write_page(vnode->cache, page, vnode->status.size,
423 fscache_uncache_page(vnode->cache, page);
424 BUG_ON(PageFsCache(page));
432 * Read a contiguous set of pages.
434 static int afs_readpages_one(struct file *file, struct address_space *mapping,
435 struct list_head *pages)
437 struct afs_vnode *vnode = AFS_FS_I(mapping->host);
438 struct afs_read *req;
440 struct page *first, *page;
441 struct key *key = afs_file_key(file);
445 /* Count the number of contiguous pages at the front of the list. Note
446 * that the list goes prev-wards rather than next-wards.
448 first = lru_to_page(pages);
449 index = first->index + 1;
451 for (p = first->lru.prev; p != pages; p = p->prev) {
452 page = list_entry(p, struct page, lru);
453 if (page->index != index)
459 req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *) * n,
464 refcount_set(&req->usage, 1);
465 req->page_done = afs_readpages_page_done;
466 req->pos = first->index;
467 req->pos <<= PAGE_SHIFT;
468 req->pages = req->array;
470 /* Transfer the pages to the request. We add them in until one fails
471 * to add to the LRU and then we stop (as that'll make a hole in the
474 * Note that it's possible for the file size to change whilst we're
475 * doing this, but we rely on the server returning less than we asked
476 * for if the file shrank. We also rely on this to deal with a partial
477 * page at the end of the file.
480 page = lru_to_page(pages);
481 list_del(&page->lru);
483 if (add_to_page_cache_lru(page, mapping, index,
484 readahead_gfp_mask(mapping))) {
485 #ifdef CONFIG_AFS_FSCACHE
486 fscache_uncache_page(vnode->cache, page);
492 req->pages[req->nr_pages++] = page;
493 req->len += PAGE_SIZE;
494 } while (req->nr_pages < n);
496 if (req->nr_pages == 0) {
501 ret = afs_fetch_data(vnode, key, req);
505 task_io_account_read(PAGE_SIZE * req->nr_pages);
510 if (ret == -ENOENT) {
511 _debug("got NOENT from server"
512 " - marking file deleted and stale");
513 set_bit(AFS_VNODE_DELETED, &vnode->flags);
517 for (i = 0; i < req->nr_pages; i++) {
518 page = req->pages[i];
520 #ifdef CONFIG_AFS_FSCACHE
521 fscache_uncache_page(vnode->cache, page);
533 * read a set of pages
535 static int afs_readpages(struct file *file, struct address_space *mapping,
536 struct list_head *pages, unsigned nr_pages)
538 struct key *key = afs_file_key(file);
539 struct afs_vnode *vnode;
542 _enter("{%d},{%lu},,%d",
543 key_serial(key), mapping->host->i_ino, nr_pages);
547 vnode = AFS_FS_I(mapping->host);
548 if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
549 _leave(" = -ESTALE");
553 /* attempt to read as many of the pages as possible */
554 #ifdef CONFIG_AFS_FSCACHE
555 ret = fscache_read_or_alloc_pages(vnode->cache,
559 afs_file_readpage_read_complete,
561 mapping_gfp_mask(mapping));
567 /* all pages are being read from the cache */
569 BUG_ON(!list_empty(pages));
570 BUG_ON(nr_pages != 0);
571 _leave(" = 0 [reading all]");
574 /* there were pages that couldn't be read from the cache */
581 _leave(" = %d", ret);
585 while (!list_empty(pages)) {
586 ret = afs_readpages_one(file, mapping, pages);
591 _leave(" = %d [netting]", ret);
596 * invalidate part or all of a page
597 * - release a page and clean up its private data if offset is 0 (indicating
600 static void afs_invalidatepage(struct page *page, unsigned int offset,
603 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
606 _enter("{%lu},%u,%u", page->index, offset, length);
608 BUG_ON(!PageLocked(page));
610 /* we clean up only if the entire page is being invalidated */
611 if (offset == 0 && length == PAGE_SIZE) {
612 #ifdef CONFIG_AFS_FSCACHE
613 if (PageFsCache(page)) {
614 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
615 fscache_wait_on_page_write(vnode->cache, page);
616 fscache_uncache_page(vnode->cache, page);
620 if (PagePrivate(page)) {
621 priv = page_private(page);
622 trace_afs_page_dirty(vnode, tracepoint_string("inval"),
624 set_page_private(page, 0);
625 ClearPagePrivate(page);
633 * release a page and clean up its private state if it's not busy
634 * - return true if the page can now be released, false if not
636 static int afs_releasepage(struct page *page, gfp_t gfp_flags)
638 struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
641 _enter("{{%llx:%llu}[%lu],%lx},%x",
642 vnode->fid.vid, vnode->fid.vnode, page->index, page->flags,
645 /* deny if page is being written to the cache and the caller hasn't
647 #ifdef CONFIG_AFS_FSCACHE
648 if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) {
649 _leave(" = F [cache busy]");
654 if (PagePrivate(page)) {
655 priv = page_private(page);
656 trace_afs_page_dirty(vnode, tracepoint_string("rel"),
658 set_page_private(page, 0);
659 ClearPagePrivate(page);
662 /* indicate that the page can be released */
668 * Handle setting up a memory mapping on an AFS file.
670 static int afs_file_mmap(struct file *file, struct vm_area_struct *vma)
674 ret = generic_file_mmap(file, vma);
676 vma->vm_ops = &afs_vm_ops;