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; 65 struct inode *inode = file->f_path.dentry->d_inode; 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 /* 75 * Another node might have truncated while we were waiting on 76 * cluster locks. 77 * We don't check size == 0 before the shift. This is borrowed 78 * from do_generic_file_read. 79 */ 80 last_index = (size - 1) >> PAGE_CACHE_SHIFT; 81 if (unlikely(!size || page->index > last_index)) { 82 ret = -EINVAL; 83 goto out; 84 } 85 86 /* 87 * The i_size check above doesn't catch the case where nodes 88 * truncated and then re-extended the file. We'll re-check the 89 * page mapping after taking the page lock inside of 90 * ocfs2_write_begin_nolock(). 91 */ 92 if (!PageUptodate(page) || page->mapping != inode->i_mapping) { 93 /* 94 * the page has been umapped in ocfs2_data_downconvert_worker. 95 * So return 0 here and let VFS retry. 96 */ 97 ret = 0; 98 goto out; 99 } 100 101 /* 102 * Call ocfs2_write_begin() and ocfs2_write_end() to take 103 * advantage of the allocation code there. We pass a write 104 * length of the whole page (chopped to i_size) to make sure 105 * the whole thing is allocated. 106 * 107 * Since we know the page is up to date, we don't have to 108 * worry about ocfs2_write_begin() skipping some buffer reads 109 * because the "write" would invalidate their data. 110 */ 111 if (page->index == last_index) 112 len = ((size - 1) & ~PAGE_CACHE_MASK) + 1; 113 114 ret = ocfs2_write_begin_nolock(file, mapping, pos, len, 0, &locked_page, 115 &fsdata, di_bh, page); 116 if (ret) { 117 if (ret != -ENOSPC) 118 mlog_errno(ret); 119 goto out; 120 } 121 122 ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page, 123 fsdata); 124 if (ret < 0) { 125 mlog_errno(ret); 126 goto out; 127 } 128 BUG_ON(ret != len); 129 ret = 0; 130 out: 131 return ret; 132 } 133 134 static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 135 { 136 struct page *page = vmf->page; 137 struct inode *inode = vma->vm_file->f_path.dentry->d_inode; 138 struct buffer_head *di_bh = NULL; 139 sigset_t oldset; 140 int ret; 141 142 ocfs2_block_signals(&oldset); 143 144 /* 145 * The cluster locks taken will block a truncate from another 146 * node. Taking the data lock will also ensure that we don't 147 * attempt page truncation as part of a downconvert. 148 */ 149 ret = ocfs2_inode_lock(inode, &di_bh, 1); 150 if (ret < 0) { 151 mlog_errno(ret); 152 goto out; 153 } 154 155 /* 156 * The alloc sem should be enough to serialize with 157 * ocfs2_truncate_file() changing i_size as well as any thread 158 * modifying the inode btree. 159 */ 160 down_write(&OCFS2_I(inode)->ip_alloc_sem); 161 162 ret = __ocfs2_page_mkwrite(vma->vm_file, di_bh, page); 163 164 up_write(&OCFS2_I(inode)->ip_alloc_sem); 165 166 brelse(di_bh); 167 ocfs2_inode_unlock(inode, 1); 168 169 out: 170 ocfs2_unblock_signals(&oldset); 171 if (ret) 172 ret = VM_FAULT_SIGBUS; 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->f_dentry->d_inode, 186 file->f_vfsmnt, &lock_level); 187 if (ret < 0) { 188 mlog_errno(ret); 189 goto out; 190 } 191 ocfs2_inode_unlock(file->f_dentry->d_inode, lock_level); 192 out: 193 vma->vm_ops = &ocfs2_file_vm_ops; 194 vma->vm_flags |= VM_CAN_NONLINEAR; 195 return 0; 196 } 197 198