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![Alexander Levin](/assets/img/avatar_default.png)
Commit77469c3f57
prevented setting the page as uptodate when we wrote the right amount of data, fix that. Fixes:77469c3f57
("9p: saner ->write_end() on failing copy into non-uptodate page") Reviewed-by: Jan Kara <jack@suse.com> Signed-off-by: Alexander Levin <alexander.levin@verizon.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
349 lines
8.2 KiB
C
349 lines
8.2 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/uio.h>
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#include <linux/bvec.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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struct inode *inode = page->mapping->host;
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struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
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struct iov_iter to;
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int retval, err;
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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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iov_iter_bvec(&to, ITER_BVEC | READ, &bvec, 1, PAGE_SIZE);
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retval = p9_client_read(fid, page_offset(page), &to, &err);
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if (err) {
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v9fs_uncache_page(inode, page);
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retval = err;
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goto done;
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}
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zero_user(page, retval, PAGE_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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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_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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struct inode *inode = page->mapping->host;
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struct v9fs_inode *v9inode = V9FS_I(inode);
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loff_t size = i_size_read(inode);
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struct iov_iter from;
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struct bio_vec bvec;
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int err, len;
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if (page->index == size >> PAGE_SHIFT)
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len = size & ~PAGE_MASK;
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else
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len = PAGE_SIZE;
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bvec.bv_page = page;
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bvec.bv_offset = 0;
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bvec.bv_len = len;
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iov_iter_bvec(&from, ITER_BVEC | WRITE, &bvec, 1, len);
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/* We should have writeback_fid always set */
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BUG_ON(!v9inode->writeback_fid);
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set_page_writeback(page);
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p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
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end_page_writeback(page);
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return err;
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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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* @iocb: target I/O control block
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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(struct kiocb *iocb, struct iov_iter *iter)
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{
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struct file *file = iocb->ki_filp;
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loff_t pos = iocb->ki_pos;
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ssize_t n;
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int err = 0;
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if (iov_iter_rw(iter) == WRITE) {
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n = p9_client_write(file->private_data, pos, iter, &err);
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if (n) {
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struct inode *inode = file_inode(file);
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loff_t i_size = i_size_read(inode);
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if (pos + n > i_size)
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inode_add_bytes(inode, pos + n - i_size);
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}
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} else {
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n = p9_client_read(file->private_data, pos, iter, &err);
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}
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return n ? n : err;
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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_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_SIZE)
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goto out;
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retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
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put_page(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 (!PageUptodate(page)) {
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if (unlikely(copied < len)) {
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copied = 0;
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goto out;
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} else if (len == PAGE_SIZE) {
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SetPageUptodate(page);
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}
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}
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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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out:
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unlock_page(page);
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put_page(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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