linux/fs/9p/vfs_addr.c
Thomas Gleixner 1f32761322 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 27 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.981318839@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:29:21 -07:00

335 lines
7.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
*/
#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 <linux/uio.h>
#include <linux/bvec.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"
#include "fid.h"
/**
* v9fs_fid_readpage - read an entire page in from 9P
*
* @fid: fid being read
* @page: structure to page
*
*/
static int v9fs_fid_readpage(struct p9_fid *fid, struct page *page)
{
struct inode *inode = page->mapping->host;
struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
struct iov_iter to;
int retval, err;
p9_debug(P9_DEBUG_VFS, "\n");
BUG_ON(!PageLocked(page));
retval = v9fs_readpage_from_fscache(inode, page);
if (retval == 0)
return retval;
iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
retval = p9_client_read(fid, page_offset(page), &to, &err);
if (err) {
v9fs_uncache_page(inode, page);
retval = err;
goto done;
}
zero_user(page, retval, PAGE_SIZE - retval);
flush_dcache_page(page);
SetPageUptodate(page);
v9fs_readpage_to_fscache(inode, page);
retval = 0;
done:
unlock_page(page);
return retval;
}
/**
* 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)
{
return v9fs_fid_readpage(filp->private_data, page);
}
/**
* 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_debug(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_debug(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 int offset,
unsigned int length)
{
/*
* If called with zero offset, we should release
* the private state assocated with the page
*/
if (offset == 0 && length == PAGE_SIZE)
v9fs_fscache_invalidate_page(page);
}
static int v9fs_vfs_writepage_locked(struct page *page)
{
struct inode *inode = page->mapping->host;
struct v9fs_inode *v9inode = V9FS_I(inode);
loff_t size = i_size_read(inode);
struct iov_iter from;
struct bio_vec bvec;
int err, len;
if (page->index == size >> PAGE_SHIFT)
len = size & ~PAGE_MASK;
else
len = PAGE_SIZE;
bvec.bv_page = page;
bvec.bv_offset = 0;
bvec.bv_len = len;
iov_iter_bvec(&from, WRITE, &bvec, 1, len);
/* We should have writeback_fid always set */
BUG_ON(!v9inode->writeback_fid);
set_page_writeback(page);
p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
end_page_writeback(page);
return err;
}
static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
{
int retval;
p9_debug(P9_DEBUG_VFS, "page %p\n", page);
retval = v9fs_vfs_writepage_locked(page);
if (retval < 0) {
if (retval == -EAGAIN) {
redirty_page_for_writepage(wbc, page);
retval = 0;
} else {
SetPageError(page);
mapping_set_error(page->mapping, retval);
}
} else
retval = 0;
unlock_page(page);
return retval;
}
/**
* v9fs_launder_page - Writeback a dirty page
* Returns 0 on success.
*/
static int v9fs_launder_page(struct page *page)
{
int retval;
struct inode *inode = page->mapping->host;
v9fs_fscache_wait_on_page_write(inode, page);
if (clear_page_dirty_for_io(page)) {
retval = v9fs_vfs_writepage_locked(page);
if (retval)
return retval;
}
return 0;
}
/**
* v9fs_direct_IO - 9P address space operation for direct I/O
* @iocb: target I/O control block
*
* 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.
*
*/
static ssize_t
v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
loff_t pos = iocb->ki_pos;
ssize_t n;
int err = 0;
if (iov_iter_rw(iter) == WRITE) {
n = p9_client_write(file->private_data, pos, iter, &err);
if (n) {
struct inode *inode = file_inode(file);
loff_t i_size = i_size_read(inode);
if (pos + n > i_size)
inode_add_bytes(inode, pos + n - i_size);
}
} else {
n = p9_client_read(file->private_data, pos, iter, &err);
}
return n ? n : err;
}
static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata)
{
int retval = 0;
struct page *page;
struct v9fs_inode *v9inode;
pgoff_t index = pos >> PAGE_SHIFT;
struct inode *inode = mapping->host;
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
v9inode = V9FS_I(inode);
start:
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page) {
retval = -ENOMEM;
goto out;
}
BUG_ON(!v9inode->writeback_fid);
if (PageUptodate(page))
goto out;
if (len == PAGE_SIZE)
goto out;
retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
put_page(page);
if (!retval)
goto start;
out:
*pagep = page;
return retval;
}
static int v9fs_write_end(struct file *filp, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
loff_t last_pos = pos + copied;
struct inode *inode = page->mapping->host;
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
if (!PageUptodate(page)) {
if (unlikely(copied < len)) {
copied = 0;
goto out;
} else if (len == PAGE_SIZE) {
SetPageUptodate(page);
}
}
/*
* No need to use i_size_read() here, the i_size
* cannot change under us because we hold the i_mutex.
*/
if (last_pos > inode->i_size) {
inode_add_bytes(inode, last_pos - inode->i_size);
i_size_write(inode, last_pos);
}
set_page_dirty(page);
out:
unlock_page(page);
put_page(page);
return copied;
}
const struct address_space_operations v9fs_addr_operations = {
.readpage = v9fs_vfs_readpage,
.readpages = v9fs_vfs_readpages,
.set_page_dirty = __set_page_dirty_nobuffers,
.writepage = v9fs_vfs_writepage,
.write_begin = v9fs_write_begin,
.write_end = v9fs_write_end,
.releasepage = v9fs_release_page,
.invalidatepage = v9fs_invalidate_page,
.launder_page = v9fs_launder_page,
.direct_IO = v9fs_direct_IO,
};