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/*
* linux/fs/9p/vfs_addr.c
*
* This file contians vfs address (mmap) ops for 9P2000.
*
* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/pagemap.h>
#include <linux/idr.h>
#include <linux/sched.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"
/**
* v9fs_vfs_readpage - read an entire page in from 9P
*
* @filp: file being read
* @page: structure to page
*
*/
static int v9fs_vfs_readpage(struct file *filp, struct page *page)
{
int retval;
loff_t offset;
char *buffer;
struct inode *inode;
inode = page->mapping->host;
P9_DPRINTK(P9_DEBUG_VFS, "\n");
BUG_ON(!PageLocked(page));
retval = v9fs_readpage_from_fscache(inode, page);
if (retval == 0)
return retval;
buffer = kmap(page);
offset = page_offset(page);
retval = v9fs_file_readn(filp, buffer, NULL, PAGE_CACHE_SIZE, offset);
if (retval < 0) {
v9fs_uncache_page(inode, page);
goto done;
}
memset(buffer + retval, 0, PAGE_CACHE_SIZE - retval);
flush_dcache_page(page);
SetPageUptodate(page);
v9fs_readpage_to_fscache(inode, page);
retval = 0;
done:
kunmap(page);
unlock_page(page);
return retval;
}
/**
* v9fs_vfs_readpages - read a set of pages from 9P
*
* @filp: file being read
* @mapping: the address space
* @pages: list of pages to read
* @nr_pages: count of pages to read
*
*/
static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
int ret = 0;
struct inode *inode;
inode = mapping->host;
P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
if (ret == 0)
return ret;
ret = read_cache_pages(mapping, pages, (void *)v9fs_vfs_readpage, filp);
P9_DPRINTK(P9_DEBUG_VFS, " = %d\n", ret);
return ret;
}
/**
* v9fs_release_page - release the private state associated with a page
*
* Returns 1 if the page can be released, false otherwise.
*/
static int v9fs_release_page(struct page *page, gfp_t gfp)
{
if (PagePrivate(page))
return 0;
return v9fs_fscache_release_page(page, gfp);
}
/**
* v9fs_invalidate_page - Invalidate a page completely or partially
*
* @page: structure to page
* @offset: offset in the page
*/
static void v9fs_invalidate_page(struct page *page, unsigned long offset)
{
if (offset == 0)
v9fs_fscache_invalidate_page(page);
}
/**
* v9fs_launder_page - Writeback a dirty page
* Since the writes go directly to the server, we simply return a 0
* here to indicate success.
*
* Returns 0 on success.
*/
static int v9fs_launder_page(struct page *page)
{
struct inode *inode = page->mapping->host;
v9fs_fscache_wait_on_page_write(inode, page);
return 0;
}
/**
* v9fs_direct_IO - 9P address space operation for direct I/O
* @rw: direction (read or write)
* @iocb: target I/O control block
* @iov: array of vectors that define I/O buffer
* @pos: offset in file to begin the operation
* @nr_segs: size of iovec array
*
* The presence of v9fs_direct_IO() in the address space ops vector
* allowes open() O_DIRECT flags which would have failed otherwise.
*
* In the non-cached mode, we shunt off direct read and write requests before
* the VFS gets them, so this method should never be called.
*
* Direct IO is not 'yet' supported in the cached mode. Hence when
* this routine is called through generic_file_aio_read(), the read/write fails
* with an error.
*
*/
ssize_t v9fs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t pos, unsigned long nr_segs)
{
P9_DPRINTK(P9_DEBUG_VFS, "v9fs_direct_IO: v9fs_direct_IO (%s) "
"off/no(%lld/%lu) EINVAL\n",
iocb->ki_filp->f_path.dentry->d_name.name,
(long long) pos, nr_segs);
return -EINVAL;
}
const struct address_space_operations v9fs_addr_operations = {
.readpage = v9fs_vfs_readpage,
.readpages = v9fs_vfs_readpages,
.releasepage = v9fs_release_page,
.invalidatepage = v9fs_invalidate_page,
.launder_page = v9fs_launder_page,
.direct_IO = v9fs_direct_IO,
};
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