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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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5cffff9e29
This patch address two shortcomings in ocfs2_page_mkwrite(): 1. Makes the function return better VM_FAULT_* errors. 2. It handles a error that is triggered when a page is dropped from the mapping due to memory pressure. This patch locks the page to prevent that. [Patch was cleaned up by Sunil Mushran.] Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
193 lines
5.0 KiB
C
193 lines
5.0 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* mmap.c
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*
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* Code to deal with the mess that is clustered mmap.
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*
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* Copyright (C) 2002, 2004 Oracle. All rights reserved.
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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
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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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 GNU
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* 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
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#include <linux/fs.h>
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#include <linux/types.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/uio.h>
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#include <linux/signal.h>
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#include <linux/rbtree.h>
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#include <cluster/masklog.h>
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#include "ocfs2.h"
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#include "aops.h"
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#include "dlmglue.h"
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#include "file.h"
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#include "inode.h"
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#include "mmap.h"
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#include "super.h"
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#include "ocfs2_trace.h"
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static int ocfs2_fault(struct vm_area_struct *area, struct vm_fault *vmf)
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{
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sigset_t oldset;
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int ret;
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ocfs2_block_signals(&oldset);
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ret = filemap_fault(area, vmf);
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ocfs2_unblock_signals(&oldset);
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trace_ocfs2_fault(OCFS2_I(area->vm_file->f_mapping->host)->ip_blkno,
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area, vmf->page, vmf->pgoff);
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return ret;
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}
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static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh,
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struct page *page)
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{
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int ret = VM_FAULT_NOPAGE;
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struct inode *inode = file->f_path.dentry->d_inode;
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struct address_space *mapping = inode->i_mapping;
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loff_t pos = page_offset(page);
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unsigned int len = PAGE_CACHE_SIZE;
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pgoff_t last_index;
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struct page *locked_page = NULL;
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void *fsdata;
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loff_t size = i_size_read(inode);
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last_index = (size - 1) >> PAGE_CACHE_SHIFT;
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/*
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* There are cases that lead to the page no longer bebongs to the
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* mapping.
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* 1) pagecache truncates locally due to memory pressure.
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* 2) pagecache truncates when another is taking EX lock against
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* inode lock. see ocfs2_data_convert_worker.
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*
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* The i_size check doesn't catch the case where nodes truncated and
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* then re-extended the file. We'll re-check the page mapping after
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* taking the page lock inside of ocfs2_write_begin_nolock().
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*
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* Let VM retry with these cases.
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*/
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if ((page->mapping != inode->i_mapping) ||
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(!PageUptodate(page)) ||
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(page_offset(page) >= size))
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goto out;
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/*
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* Call ocfs2_write_begin() and ocfs2_write_end() to take
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* advantage of the allocation code there. We pass a write
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* length of the whole page (chopped to i_size) to make sure
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* the whole thing is allocated.
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*
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* Since we know the page is up to date, we don't have to
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* worry about ocfs2_write_begin() skipping some buffer reads
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* because the "write" would invalidate their data.
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*/
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if (page->index == last_index)
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len = ((size - 1) & ~PAGE_CACHE_MASK) + 1;
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ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &locked_page,
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&fsdata, di_bh, page);
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if (ret) {
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if (ret != -ENOSPC)
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mlog_errno(ret);
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if (ret == -ENOMEM)
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ret = VM_FAULT_OOM;
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else
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ret = VM_FAULT_SIGBUS;
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goto out;
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}
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if (!locked_page) {
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ret = VM_FAULT_NOPAGE;
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goto out;
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}
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ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
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fsdata);
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BUG_ON(ret != len);
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ret = VM_FAULT_LOCKED;
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out:
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return ret;
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}
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static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct page *page = vmf->page;
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struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
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struct buffer_head *di_bh = NULL;
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sigset_t oldset;
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int ret;
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ocfs2_block_signals(&oldset);
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/*
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* The cluster locks taken will block a truncate from another
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* node. Taking the data lock will also ensure that we don't
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* attempt page truncation as part of a downconvert.
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*/
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ret = ocfs2_inode_lock(inode, &di_bh, 1);
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if (ret < 0) {
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mlog_errno(ret);
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goto out;
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}
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/*
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* The alloc sem should be enough to serialize with
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* ocfs2_truncate_file() changing i_size as well as any thread
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* modifying the inode btree.
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*/
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down_write(&OCFS2_I(inode)->ip_alloc_sem);
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ret = __ocfs2_page_mkwrite(vma->vm_file, di_bh, page);
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up_write(&OCFS2_I(inode)->ip_alloc_sem);
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brelse(di_bh);
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ocfs2_inode_unlock(inode, 1);
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out:
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ocfs2_unblock_signals(&oldset);
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return ret;
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}
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static const struct vm_operations_struct ocfs2_file_vm_ops = {
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.fault = ocfs2_fault,
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.page_mkwrite = ocfs2_page_mkwrite,
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};
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int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
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{
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int ret = 0, lock_level = 0;
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ret = ocfs2_inode_lock_atime(file->f_dentry->d_inode,
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file->f_vfsmnt, &lock_level);
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if (ret < 0) {
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mlog_errno(ret);
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goto out;
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}
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ocfs2_inode_unlock(file->f_dentry->d_inode, lock_level);
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out:
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vma->vm_ops = &ocfs2_file_vm_ops;
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vma->vm_flags |= VM_CAN_NONLINEAR;
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return 0;
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}
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