1 /* -*- mode: c; c-basic-offset: 8; -*- 2 * vim: noexpandtab sw=8 ts=8 sts=0: 3 * 4 * mmap.c 5 * 6 * Code to deal with the mess that is clustered mmap. 7 * 8 * Copyright (C) 2002, 2004 Oracle. All rights reserved. 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public 12 * License as published by the Free Software Foundation; either 13 * version 2 of the License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public 21 * License along with this program; if not, write to the 22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 23 * Boston, MA 021110-1307, USA. 24 */ 25 26 #include <linux/fs.h> 27 #include <linux/types.h> 28 #include <linux/highmem.h> 29 #include <linux/pagemap.h> 30 #include <linux/uio.h> 31 #include <linux/signal.h> 32 #include <linux/rbtree.h> 33 34 #include <cluster/masklog.h> 35 36 #include "ocfs2.h" 37 38 #include "aops.h" 39 #include "dlmglue.h" 40 #include "file.h" 41 #include "inode.h" 42 #include "mmap.h" 43 #include "super.h" 44 #include "ocfs2_trace.h" 45 46 47 static int ocfs2_fault(struct vm_area_struct *area, struct vm_fault *vmf) 48 { 49 sigset_t oldset; 50 int ret; 51 52 ocfs2_block_signals(&oldset); 53 ret = filemap_fault(area, vmf); 54 ocfs2_unblock_signals(&oldset); 55 56 trace_ocfs2_fault(OCFS2_I(area->vm_file->f_mapping->host)->ip_blkno, 57 area, vmf->page, vmf->pgoff); 58 return ret; 59 } 60 61 static int __ocfs2_page_mkwrite(struct file *file, struct buffer_head *di_bh, 62 struct page *page) 63 { 64 int ret = VM_FAULT_NOPAGE; 65 struct inode *inode = file_inode(file); 66 struct address_space *mapping = inode->i_mapping; 67 loff_t pos = page_offset(page); 68 unsigned int len = PAGE_CACHE_SIZE; 69 pgoff_t last_index; 70 struct page *locked_page = NULL; 71 void *fsdata; 72 loff_t size = i_size_read(inode); 73 74 last_index = (size - 1) >> PAGE_CACHE_SHIFT; 75 76 /* 77 * There are cases that lead to the page no longer bebongs to the 78 * mapping. 79 * 1) pagecache truncates locally due to memory pressure. 80 * 2) pagecache truncates when another is taking EX lock against 81 * inode lock. see ocfs2_data_convert_worker. 82 * 83 * The i_size check doesn't catch the case where nodes truncated and 84 * then re-extended the file. We'll re-check the page mapping after 85 * taking the page lock inside of ocfs2_write_begin_nolock(). 86 * 87 * Let VM retry with these cases. 88 */ 89 if ((page->mapping != inode->i_mapping) || 90 (!PageUptodate(page)) || 91 (page_offset(page) >= size)) 92 goto out; 93 94 /* 95 * Call ocfs2_write_begin() and ocfs2_write_end() to take 96 * advantage of the allocation code there. We pass a write 97 * length of the whole page (chopped to i_size) to make sure 98 * the whole thing is allocated. 99 * 100 * Since we know the page is up to date, we don't have to 101 * worry about ocfs2_write_begin() skipping some buffer reads 102 * because the "write" would invalidate their data. 103 */ 104 if (page->index == last_index) 105 len = ((size - 1) & ~PAGE_CACHE_MASK) + 1; 106 107 ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &locked_page, 108 &fsdata, di_bh, page); 109 if (ret) { 110 if (ret != -ENOSPC) 111 mlog_errno(ret); 112 if (ret == -ENOMEM) 113 ret = VM_FAULT_OOM; 114 else 115 ret = VM_FAULT_SIGBUS; 116 goto out; 117 } 118 119 if (!locked_page) { 120 ret = VM_FAULT_NOPAGE; 121 goto out; 122 } 123 ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page, 124 fsdata); 125 BUG_ON(ret != len); 126 ret = VM_FAULT_LOCKED; 127 out: 128 return ret; 129 } 130 131 static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 132 { 133 struct page *page = vmf->page; 134 struct inode *inode = file_inode(vma->vm_file); 135 struct buffer_head *di_bh = NULL; 136 sigset_t oldset; 137 int ret; 138 139 sb_start_pagefault(inode->i_sb); 140 ocfs2_block_signals(&oldset); 141 142 /* 143 * The cluster locks taken will block a truncate from another 144 * node. Taking the data lock will also ensure that we don't 145 * attempt page truncation as part of a downconvert. 146 */ 147 ret = ocfs2_inode_lock(inode, &di_bh, 1); 148 if (ret < 0) { 149 mlog_errno(ret); 150 goto out; 151 } 152 153 /* 154 * The alloc sem should be enough to serialize with 155 * ocfs2_truncate_file() changing i_size as well as any thread 156 * modifying the inode btree. 157 */ 158 down_write(&OCFS2_I(inode)->ip_alloc_sem); 159 160 ret = __ocfs2_page_mkwrite(vma->vm_file, di_bh, page); 161 162 up_write(&OCFS2_I(inode)->ip_alloc_sem); 163 164 brelse(di_bh); 165 ocfs2_inode_unlock(inode, 1); 166 167 out: 168 ocfs2_unblock_signals(&oldset); 169 sb_end_pagefault(inode->i_sb); 170 return ret; 171 } 172 173 static const struct vm_operations_struct ocfs2_file_vm_ops = { 174 .fault = ocfs2_fault, 175 .page_mkwrite = ocfs2_page_mkwrite, 176 }; 177 178 int ocfs2_mmap(struct file *file, struct vm_area_struct *vma) 179 { 180 int ret = 0, lock_level = 0; 181 182 ret = ocfs2_inode_lock_atime(file_inode(file), 183 file->f_path.mnt, &lock_level); 184 if (ret < 0) { 185 mlog_errno(ret); 186 goto out; 187 } 188 ocfs2_inode_unlock(file_inode(file), lock_level); 189 out: 190 vma->vm_ops = &ocfs2_file_vm_ops; 191 return 0; 192 } 193 194