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c2ec175c39
Change the page_mkwrite prototype to take a struct vm_fault, and return VM_FAULT_xxx flags. There should be no functional change. This makes it possible to return much more detailed error information to the VM (and also can provide more information eg. virtual_address to the driver, which might be important in some special cases). This is required for a subsequent fix. And will also make it easier to merge page_mkwrite() with fault() in future. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Chris Mason <chris.mason@oracle.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Artem Bityutskiy <dedekind@infradead.org> Cc: Felix Blyakher <felixb@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
227 lines
5.6 KiB
C
227 lines
5.6 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/slab.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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#define MLOG_MASK_PREFIX ML_FILE_IO
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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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static inline int ocfs2_vm_op_block_sigs(sigset_t *blocked, sigset_t *oldset)
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{
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/* The best way to deal with signals in the vm path is
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* to block them upfront, rather than allowing the
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* locking paths to return -ERESTARTSYS. */
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sigfillset(blocked);
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/* We should technically never get a bad return value
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* from sigprocmask */
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return sigprocmask(SIG_BLOCK, blocked, oldset);
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}
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static inline int ocfs2_vm_op_unblock_sigs(sigset_t *oldset)
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{
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return sigprocmask(SIG_SETMASK, oldset, NULL);
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}
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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 blocked, oldset;
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int error, ret;
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mlog_entry("(area=%p, page offset=%lu)\n", area, vmf->pgoff);
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error = ocfs2_vm_op_block_sigs(&blocked, &oldset);
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if (error < 0) {
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mlog_errno(error);
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ret = VM_FAULT_SIGBUS;
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goto out;
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}
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ret = filemap_fault(area, vmf);
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error = ocfs2_vm_op_unblock_sigs(&oldset);
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if (error < 0)
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mlog_errno(error);
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out:
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mlog_exit_ptr(vmf->page);
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return ret;
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}
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static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
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struct page *page)
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{
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int ret;
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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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/*
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* Another node might have truncated while we were waiting on
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* cluster locks.
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*/
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last_index = size >> PAGE_CACHE_SHIFT;
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if (page->index > last_index) {
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ret = -EINVAL;
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goto out;
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}
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/*
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* The i_size check above doesn't catch the case where nodes
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* truncated and then re-extended the file. We'll re-check the
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* page mapping after taking the page lock inside of
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* ocfs2_write_begin_nolock().
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*/
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if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
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/*
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* the page has been umapped in ocfs2_data_downconvert_worker.
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* So return 0 here and let VFS retry.
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*/
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ret = 0;
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goto out;
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}
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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 & ~PAGE_CACHE_MASK;
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ret = ocfs2_write_begin_nolock(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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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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if (ret < 0) {
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mlog_errno(ret);
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goto out;
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}
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BUG_ON(ret != len);
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ret = 0;
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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 blocked, oldset;
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int ret, ret2;
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ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
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if (ret < 0) {
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mlog_errno(ret);
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return ret;
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}
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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(inode, 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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ret2 = ocfs2_vm_op_unblock_sigs(&oldset);
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if (ret2 < 0)
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mlog_errno(ret2);
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if (ret)
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ret = VM_FAULT_SIGBUS;
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return ret;
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}
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static 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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