/* -*- mode: c; c-basic-offset: 8; -*- * vim: noexpandtab sw=8 ts=8 sts=0: * * mmap.c * * Code to deal with the mess that is clustered mmap. * * Copyright (C) 2002, 2004 Oracle. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * 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 the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include <linux/fs.h> #include <linux/types.h> #include <linux/highmem.h> #include <linux/pagemap.h> #include <linux/uio.h> #include <linux/signal.h> #include <linux/rbtree.h> #include <cluster/masklog.h> #include "ocfs2.h" #include "aops.h" #include "dlmglue.h" #include "file.h" #include "inode.h" #include "mmap.h" #include "super.h" #include "ocfs2_trace.h" static int ocfs2_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; sigset_t oldset; int ret; ocfs2_block_signals(&oldset); ret = filemap_fault(vmf); ocfs2_unblock_signals(&oldset); trace_ocfs2_fault(OCFS2_I(vma->vm_file->f_mapping->host)->ip_blkno, vma, vmf->page, vmf->pgoff); return ret; } static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh, struct page *page) { int ret = VM_FAULT_NOPAGE; struct inode *inode = file_inode(file); struct address_space *mapping = inode->i_mapping; loff_t pos = page_offset(page); unsigned int len = PAGE_SIZE; pgoff_t last_index; struct page *locked_page = NULL; void *fsdata; loff_t size = i_size_read(inode); last_index = (size - 1) >> PAGE_SHIFT; /* * There are cases that lead to the page no longer bebongs to the * mapping. * 1) pagecache truncates locally due to memory pressure. * 2) pagecache truncates when another is taking EX lock against * inode lock. see ocfs2_data_convert_worker. * * The i_size check doesn't catch the case where nodes truncated and * then re-extended the file. We'll re-check the page mapping after * taking the page lock inside of ocfs2_write_begin_nolock(). * * Let VM retry with these cases. */ if ((page->mapping != inode->i_mapping) || (!PageUptodate(page)) || (page_offset(page) >= size)) goto out; /* * Call ocfs2_write_begin() and ocfs2_write_end() to take * advantage of the allocation code there. We pass a write * length of the whole page (chopped to i_size) to make sure * the whole thing is allocated. * * Since we know the page is up to date, we don't have to * worry about ocfs2_write_begin() skipping some buffer reads * because the "write" would invalidate their data. */ if (page->index == last_index) len = ((size - 1) & ~PAGE_MASK) + 1; ret = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_MMAP, &locked_page, &fsdata, di_bh, page); if (ret) { if (ret != -ENOSPC) mlog_errno(ret); if (ret == -ENOMEM) ret = VM_FAULT_OOM; else ret = VM_FAULT_SIGBUS; goto out; } if (!locked_page) { ret = VM_FAULT_NOPAGE; goto out; } ret = ocfs2_write_end_nolock(mapping, pos, len, len, fsdata); BUG_ON(ret != len); ret = VM_FAULT_LOCKED; out: return ret; } static int ocfs2_page_mkwrite(struct vm_fault *vmf) { struct page *page = vmf->page; struct inode *inode = file_inode(vmf->vma->vm_file); struct buffer_head *di_bh = NULL; sigset_t oldset; int ret; sb_start_pagefault(inode->i_sb); ocfs2_block_signals(&oldset); /* * The cluster locks taken will block a truncate from another * node. Taking the data lock will also ensure that we don't * attempt page truncation as part of a downconvert. */ ret = ocfs2_inode_lock(inode, &di_bh, 1); if (ret < 0) { mlog_errno(ret); if (ret == -ENOMEM) ret = VM_FAULT_OOM; else ret = VM_FAULT_SIGBUS; goto out; } /* * The alloc sem should be enough to serialize with * ocfs2_truncate_file() changing i_size as well as any thread * modifying the inode btree. */ down_write(&OCFS2_I(inode)->ip_alloc_sem); ret = __ocfs2_page_mkwrite(vmf->vma->vm_file, di_bh, page); up_write(&OCFS2_I(inode)->ip_alloc_sem); brelse(di_bh); ocfs2_inode_unlock(inode, 1); out: ocfs2_unblock_signals(&oldset); sb_end_pagefault(inode->i_sb); return ret; } static const struct vm_operations_struct ocfs2_file_vm_ops = { .fault = ocfs2_fault, .page_mkwrite = ocfs2_page_mkwrite, }; int ocfs2_mmap(struct file *file, struct vm_area_struct *vma) { int ret = 0, lock_level = 0; ret = ocfs2_inode_lock_atime(file_inode(file), file->f_path.mnt, &lock_level, 1); if (ret < 0) { mlog_errno(ret); goto out; } ocfs2_inode_unlock(file_inode(file), lock_level); out: vma->vm_ops = &ocfs2_file_vm_ops; return 0; }