--- /dev/null
+/* -*- 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_area_struct *area, struct vm_fault *vmf)
+{
+ sigset_t oldset;
+ int ret;
+
+ ocfs2_block_signals(&oldset);
+ ret = filemap_fault(area, vmf);
+ ocfs2_unblock_signals(&oldset);
+
+ trace_ocfs2_fault(OCFS2_I(area->vm_file->f_mapping->host)->ip_blkno,
+ area, 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_CACHE_SIZE;
+ pgoff_t last_index;
+ struct page *locked_page = NULL;
+ void *fsdata;
+ loff_t size = i_size_read(inode);
+
+ last_index = (size - 1) >> PAGE_CACHE_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_CACHE_MASK) + 1;
+
+ ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &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, locked_page,
+ fsdata);
+ BUG_ON(ret != len);
+ ret = VM_FAULT_LOCKED;
+out:
+ return ret;
+}
+
+static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct page *page = vmf->page;
+ struct inode *inode = file_inode(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);
+ 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(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);
+ 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;
+}
+
Code Review / kvmfornfv.git / blobdiff