![Christoph Hellwig](/assets/img/avatar_default.png)
Same as with already do with the file operations: keep them in .rodata and prevents people from doing runtime patching. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Steven French <sfrench@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
274 lines
6.4 KiB
C
274 lines
6.4 KiB
C
/* file.c: AFS filesystem file handling
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*
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* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/pagemap.h>
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#include <linux/buffer_head.h>
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#include "volume.h"
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#include "vnode.h"
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#include <rxrpc/call.h>
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#include "internal.h"
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#if 0
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static int afs_file_open(struct inode *inode, struct file *file);
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static int afs_file_release(struct inode *inode, struct file *file);
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#endif
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static int afs_file_readpage(struct file *file, struct page *page);
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static void afs_file_invalidatepage(struct page *page, unsigned long offset);
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static int afs_file_releasepage(struct page *page, gfp_t gfp_flags);
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struct inode_operations afs_file_inode_operations = {
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.getattr = afs_inode_getattr,
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};
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const struct address_space_operations afs_fs_aops = {
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.readpage = afs_file_readpage,
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.sync_page = block_sync_page,
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.set_page_dirty = __set_page_dirty_nobuffers,
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.releasepage = afs_file_releasepage,
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.invalidatepage = afs_file_invalidatepage,
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};
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/*****************************************************************************/
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/*
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* deal with notification that a page was read from the cache
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*/
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#ifdef AFS_CACHING_SUPPORT
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static void afs_file_readpage_read_complete(void *cookie_data,
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struct page *page,
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void *data,
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int error)
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{
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_enter("%p,%p,%p,%d", cookie_data, page, data, error);
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if (error)
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SetPageError(page);
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else
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SetPageUptodate(page);
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unlock_page(page);
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} /* end afs_file_readpage_read_complete() */
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#endif
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/*****************************************************************************/
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/*
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* deal with notification that a page was written to the cache
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*/
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#ifdef AFS_CACHING_SUPPORT
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static void afs_file_readpage_write_complete(void *cookie_data,
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struct page *page,
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void *data,
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int error)
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{
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_enter("%p,%p,%p,%d", cookie_data, page, data, error);
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unlock_page(page);
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} /* end afs_file_readpage_write_complete() */
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#endif
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/*****************************************************************************/
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/*
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* AFS read page from file (or symlink)
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*/
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static int afs_file_readpage(struct file *file, struct page *page)
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{
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struct afs_rxfs_fetch_descriptor desc;
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#ifdef AFS_CACHING_SUPPORT
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struct cachefs_page *pageio;
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#endif
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struct afs_vnode *vnode;
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struct inode *inode;
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int ret;
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inode = page->mapping->host;
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_enter("{%lu},{%lu}", inode->i_ino, page->index);
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vnode = AFS_FS_I(inode);
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BUG_ON(!PageLocked(page));
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ret = -ESTALE;
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if (vnode->flags & AFS_VNODE_DELETED)
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goto error;
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#ifdef AFS_CACHING_SUPPORT
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ret = cachefs_page_get_private(page, &pageio, GFP_NOIO);
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if (ret < 0)
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goto error;
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/* is it cached? */
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ret = cachefs_read_or_alloc_page(vnode->cache,
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page,
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afs_file_readpage_read_complete,
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NULL,
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GFP_KERNEL);
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#else
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ret = -ENOBUFS;
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#endif
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switch (ret) {
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/* read BIO submitted and wb-journal entry found */
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case 1:
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BUG(); // TODO - handle wb-journal match
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/* read BIO submitted (page in cache) */
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case 0:
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break;
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/* no page available in cache */
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case -ENOBUFS:
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case -ENODATA:
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default:
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desc.fid = vnode->fid;
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desc.offset = page->index << PAGE_CACHE_SHIFT;
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desc.size = min((size_t) (inode->i_size - desc.offset),
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(size_t) PAGE_SIZE);
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desc.buffer = kmap(page);
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clear_page(desc.buffer);
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/* read the contents of the file from the server into the
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* page */
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ret = afs_vnode_fetch_data(vnode, &desc);
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kunmap(page);
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if (ret < 0) {
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if (ret==-ENOENT) {
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_debug("got NOENT from server"
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" - marking file deleted and stale");
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vnode->flags |= AFS_VNODE_DELETED;
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ret = -ESTALE;
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}
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#ifdef AFS_CACHING_SUPPORT
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cachefs_uncache_page(vnode->cache, page);
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#endif
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goto error;
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}
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SetPageUptodate(page);
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#ifdef AFS_CACHING_SUPPORT
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if (cachefs_write_page(vnode->cache,
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page,
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afs_file_readpage_write_complete,
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NULL,
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GFP_KERNEL) != 0
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) {
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cachefs_uncache_page(vnode->cache, page);
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unlock_page(page);
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}
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#else
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unlock_page(page);
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#endif
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}
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_leave(" = 0");
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return 0;
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error:
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SetPageError(page);
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unlock_page(page);
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_leave(" = %d", ret);
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return ret;
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} /* end afs_file_readpage() */
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/*****************************************************************************/
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/*
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* get a page cookie for the specified page
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*/
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#ifdef AFS_CACHING_SUPPORT
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int afs_cache_get_page_cookie(struct page *page,
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struct cachefs_page **_page_cookie)
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{
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int ret;
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_enter("");
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ret = cachefs_page_get_private(page,_page_cookie, GFP_NOIO);
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_leave(" = %d", ret);
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return ret;
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} /* end afs_cache_get_page_cookie() */
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#endif
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/*****************************************************************************/
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/*
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* invalidate part or all of a page
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*/
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static void afs_file_invalidatepage(struct page *page, unsigned long offset)
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{
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int ret = 1;
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_enter("{%lu},%lu", page->index, offset);
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BUG_ON(!PageLocked(page));
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if (PagePrivate(page)) {
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#ifdef AFS_CACHING_SUPPORT
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struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
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cachefs_uncache_page(vnode->cache,page);
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#endif
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/* We release buffers only if the entire page is being
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* invalidated.
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* The get_block cached value has been unconditionally
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* invalidated, so real IO is not possible anymore.
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*/
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if (offset == 0) {
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BUG_ON(!PageLocked(page));
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ret = 0;
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if (!PageWriteback(page))
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ret = page->mapping->a_ops->releasepage(page,
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0);
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/* possibly should BUG_ON(!ret); - neilb */
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}
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}
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_leave(" = %d", ret);
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} /* end afs_file_invalidatepage() */
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/*****************************************************************************/
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/*
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* release a page and cleanup its private data
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*/
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static int afs_file_releasepage(struct page *page, gfp_t gfp_flags)
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{
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struct cachefs_page *pageio;
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_enter("{%lu},%x", page->index, gfp_flags);
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if (PagePrivate(page)) {
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#ifdef AFS_CACHING_SUPPORT
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struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
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cachefs_uncache_page(vnode->cache, page);
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#endif
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pageio = (struct cachefs_page *) page_private(page);
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set_page_private(page, 0);
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ClearPagePrivate(page);
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kfree(pageio);
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}
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_leave(" = 0");
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return 0;
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} /* end afs_file_releasepage() */
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