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_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_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_MASK) + 1; 106 107 ret = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_MMAP, 108 &locked_page, &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, fsdata); 124 BUG_ON(ret != len); 125 ret = VM_FAULT_LOCKED; 126 out: 127 return ret; 128 } 129 130 static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 131 { 132 struct page *page = vmf->page; 133 struct inode *inode = file_inode(vma->vm_file); 134 struct buffer_head *di_bh = NULL; 135 sigset_t oldset; 136 int ret; 137 138 sb_start_pagefault(inode->i_sb); 139 ocfs2_block_signals(&oldset); 140 141 /* 142 * The cluster locks taken will block a truncate from another 143 * node. Taking the data lock will also ensure that we don't 144 * attempt page truncation as part of a downconvert. 145 */ 146 ret = ocfs2_inode_lock(inode, &di_bh, 1); 147 if (ret < 0) { 148 mlog_errno(ret); 149 if (ret == -ENOMEM) 150 ret = VM_FAULT_OOM; 151 else 152 ret = VM_FAULT_SIGBUS; 153 goto out; 154 } 155 156 /* 157 * The alloc sem should be enough to serialize with 158 * ocfs2_truncate_file() changing i_size as well as any thread 159 * modifying the inode btree. 160 */ 161 down_write(&OCFS2_I(inode)->ip_alloc_sem); 162 163 ret = __ocfs2_page_mkwrite(vma->vm_file, di_bh, page); 164 165 up_write(&OCFS2_I(inode)->ip_alloc_sem); 166 167 brelse(di_bh); 168 ocfs2_inode_unlock(inode, 1); 169 170 out: 171 ocfs2_unblock_signals(&oldset); 172 sb_end_pagefault(inode->i_sb); 173 return ret; 174 } 175 176 static const struct vm_operations_struct ocfs2_file_vm_ops = { 177 .fault = ocfs2_fault, 178 .page_mkwrite = ocfs2_page_mkwrite, 179 }; 180 181 int ocfs2_mmap(struct file *file, struct vm_area_struct *vma) 182 { 183 int ret = 0, lock_level = 0; 184 185 ret = ocfs2_inode_lock_atime(file_inode(file), 186 file->f_path.mnt, &lock_level); 187 if (ret < 0) { 188 mlog_errno(ret); 189 goto out; 190 } 191 ocfs2_inode_unlock(file_inode(file), lock_level); 192 out: 193 vma->vm_ops = &ocfs2_file_vm_ops; 194 return 0; 195 } 196 197