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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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fb89b45cdf
- Add cache=mmap option - Make mmap read-write while keeping it as synchronous as possible - Build writeback fid on mmap creation if it is writable Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
362 lines
8.4 KiB
C
362 lines
8.4 KiB
C
/*
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* linux/fs/9p/vfs_addr.c
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*
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* This file contians vfs address (mmap) ops for 9P2000.
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*
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* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
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* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/inet.h>
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#include <linux/pagemap.h>
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#include <linux/idr.h>
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#include <linux/sched.h>
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#include <linux/aio.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include "v9fs.h"
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#include "v9fs_vfs.h"
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#include "cache.h"
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#include "fid.h"
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/**
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* v9fs_fid_readpage - read an entire page in from 9P
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*
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* @fid: fid being read
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* @page: structure to page
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*
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*/
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static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
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{
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int retval;
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loff_t offset;
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char *buffer;
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struct inode *inode;
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inode = page->mapping->host;
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p9_debug(P9_DEBUG_VFS, "\n");
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BUG_ON(!PageLocked(page));
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retval = v9fs_readpage_from_fscache(inode, page);
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if (retval == 0)
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return retval;
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buffer = kmap(page);
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offset = page_offset(page);
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retval = v9fs_fid_readn(fid, buffer, NULL, PAGE_CACHE_SIZE, offset);
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if (retval < 0) {
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v9fs_uncache_page(inode, page);
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goto done;
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}
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memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
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flush_dcache_page(page);
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SetPageUptodate(page);
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v9fs_readpage_to_fscache(inode, page);
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retval = 0;
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done:
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kunmap(page);
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unlock_page(page);
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return retval;
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}
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/**
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* v9fs_vfs_readpage - read an entire page in from 9P
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*
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* @filp: file being read
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* @page: structure to page
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*
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*/
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static int v9fs_vfs_readpage(struct file *filp, struct page *page)
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{
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return v9fs_fid_readpage(filp->private_data, page);
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}
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/**
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* v9fs_vfs_readpages - read a set of pages from 9P
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*
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* @filp: file being read
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* @mapping: the address space
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* @pages: list of pages to read
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* @nr_pages: count of pages to read
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*
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*/
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static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
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struct list_head *pages, unsigned nr_pages)
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{
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int ret = 0;
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struct inode *inode;
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inode = mapping->host;
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p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
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ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
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if (ret == 0)
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return ret;
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ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
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p9_debug(P9_DEBUG_VFS, " = %d\n", ret);
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return ret;
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}
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/**
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* v9fs_release_page - release the private state associated with a page
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*
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* Returns 1 if the page can be released, false otherwise.
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*/
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static int v9fs_release_page(struct page *page, gfp_t gfp)
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{
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if (PagePrivate(page))
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return 0;
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return v9fs_fscache_release_page(page, gfp);
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}
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/**
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* v9fs_invalidate_page - Invalidate a page completely or partially
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*
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* @page: structure to page
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* @offset: offset in the page
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*/
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static void v9fs_invalidate_page(struct page *page, unsigned int offset,
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unsigned int length)
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{
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/*
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* If called with zero offset, we should release
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* the private state assocated with the page
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*/
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if (offset == 0 && length == PAGE_CACHE_SIZE)
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v9fs_fscache_invalidate_page(page);
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}
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static int v9fs_vfs_writepage_locked(struct page *page)
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{
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char *buffer;
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int retval, len;
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loff_t offset, size;
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mm_segment_t old_fs;
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struct v9fs_inode *v9inode;
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struct inode *inode = page->mapping->host;
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v9inode = V9FS_I(inode);
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size = i_size_read(inode);
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if (page->index == size >> PAGE_CACHE_SHIFT)
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len = size & ~PAGE_CACHE_MASK;
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else
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len = PAGE_CACHE_SIZE;
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set_page_writeback(page);
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buffer = kmap(page);
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offset = page_offset(page);
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old_fs = get_fs();
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set_fs(get_ds());
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/* We should have writeback_fid always set */
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BUG_ON(!v9inode->writeback_fid);
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retval = v9fs_file_write_internal(inode,
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v9inode->writeback_fid,
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(__force const char __user *)buffer,
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len, &offset, 0);
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if (retval > 0)
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retval = 0;
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set_fs(old_fs);
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kunmap(page);
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end_page_writeback(page);
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return retval;
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}
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static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
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{
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int retval;
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p9_debug(P9_DEBUG_VFS, "page %p\n", page);
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retval = v9fs_vfs_writepage_locked(page);
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if (retval < 0) {
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if (retval == -EAGAIN) {
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redirty_page_for_writepage(wbc, page);
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retval = 0;
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} else {
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SetPageError(page);
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mapping_set_error(page->mapping, retval);
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}
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} else
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retval = 0;
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unlock_page(page);
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return retval;
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}
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/**
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* v9fs_launder_page - Writeback a dirty page
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* Returns 0 on success.
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*/
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static int v9fs_launder_page(struct page *page)
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{
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int retval;
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struct inode *inode = page->mapping->host;
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v9fs_fscache_wait_on_page_write(inode, page);
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if (clear_page_dirty_for_io(page)) {
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retval = v9fs_vfs_writepage_locked(page);
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if (retval)
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return retval;
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}
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return 0;
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}
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/**
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* v9fs_direct_IO - 9P address space operation for direct I/O
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* @rw: direction (read or write)
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* @iocb: target I/O control block
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* @iov: array of vectors that define I/O buffer
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* @pos: offset in file to begin the operation
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* @nr_segs: size of iovec array
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*
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* The presence of v9fs_direct_IO() in the address space ops vector
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* allowes open() O_DIRECT flags which would have failed otherwise.
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*
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* In the non-cached mode, we shunt off direct read and write requests before
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* the VFS gets them, so this method should never be called.
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*
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* Direct IO is not 'yet' supported in the cached mode. Hence when
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* this routine is called through generic_file_aio_read(), the read/write fails
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* with an error.
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*
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*/
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static ssize_t
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v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
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loff_t pos, unsigned long nr_segs)
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{
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/*
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* FIXME
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* Now that we do caching with cache mode enabled, We need
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* to support direct IO
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*/
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p9_debug(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) off/no(%lld/%lu) EINVAL\n",
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iocb->ki_filp->f_path.dentry->d_name.name,
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(long long)pos, nr_segs);
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return -EINVAL;
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}
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static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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int retval = 0;
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struct page *page;
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struct v9fs_inode *v9inode;
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pgoff_t index = pos >> PAGE_CACHE_SHIFT;
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struct inode *inode = mapping->host;
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p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
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v9inode = V9FS_I(inode);
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start:
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page = grab_cache_page_write_begin(mapping, index, flags);
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if (!page) {
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retval = -ENOMEM;
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goto out;
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}
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BUG_ON(!v9inode->writeback_fid);
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if (PageUptodate(page))
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goto out;
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if (len == PAGE_CACHE_SIZE)
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goto out;
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retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
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page_cache_release(page);
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if (!retval)
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goto start;
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out:
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*pagep = page;
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return retval;
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}
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static int v9fs_write_end(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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loff_t last_pos = pos + copied;
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struct inode *inode = page->mapping->host;
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p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
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if (unlikely(copied < len)) {
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/*
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* zero out the rest of the area
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*/
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unsigned from = pos & (PAGE_CACHE_SIZE - 1);
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zero_user(page, from + copied, len - copied);
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flush_dcache_page(page);
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}
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if (!PageUptodate(page))
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SetPageUptodate(page);
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/*
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* No need to use i_size_read() here, the i_size
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* cannot change under us because we hold the i_mutex.
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*/
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if (last_pos > inode->i_size) {
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inode_add_bytes(inode, last_pos - inode->i_size);
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i_size_write(inode, last_pos);
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}
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set_page_dirty(page);
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unlock_page(page);
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page_cache_release(page);
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return copied;
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}
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const struct address_space_operations v9fs_addr_operations = {
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.readpage = v9fs_vfs_readpage,
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.readpages = v9fs_vfs_readpages,
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.set_page_dirty = __set_page_dirty_nobuffers,
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.writepage = v9fs_vfs_writepage,
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.write_begin = v9fs_write_begin,
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.write_end = v9fs_write_end,
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.releasepage = v9fs_release_page,
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.invalidatepage = v9fs_invalidate_page,
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.launder_page = v9fs_launder_page,
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.direct_IO = v9fs_direct_IO,
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};
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