1 /* 2 * file.c - NILFS regular file handling primitives including fsync(). 3 * 4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * Written by Amagai Yoshiji and Ryusuke Konishi. 17 */ 18 19 #include <linux/fs.h> 20 #include <linux/mm.h> 21 #include <linux/writeback.h> 22 #include "nilfs.h" 23 #include "segment.h" 24 25 int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) 26 { 27 /* 28 * Called from fsync() system call 29 * This is the only entry point that can catch write and synch 30 * timing for both data blocks and intermediate blocks. 31 * 32 * This function should be implemented when the writeback function 33 * will be implemented. 34 */ 35 struct the_nilfs *nilfs; 36 struct inode *inode = file->f_mapping->host; 37 int err = 0; 38 39 if (nilfs_inode_dirty(inode)) { 40 if (datasync) 41 err = nilfs_construct_dsync_segment(inode->i_sb, inode, 42 start, end); 43 else 44 err = nilfs_construct_segment(inode->i_sb); 45 } 46 47 nilfs = inode->i_sb->s_fs_info; 48 if (!err) 49 err = nilfs_flush_device(nilfs); 50 51 return err; 52 } 53 54 static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf) 55 { 56 struct vm_area_struct *vma = vmf->vma; 57 struct page *page = vmf->page; 58 struct inode *inode = file_inode(vma->vm_file); 59 struct nilfs_transaction_info ti; 60 int ret = 0; 61 62 if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info))) 63 return VM_FAULT_SIGBUS; /* -ENOSPC */ 64 65 sb_start_pagefault(inode->i_sb); 66 lock_page(page); 67 if (page->mapping != inode->i_mapping || 68 page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) { 69 unlock_page(page); 70 ret = -EFAULT; /* make the VM retry the fault */ 71 goto out; 72 } 73 74 /* 75 * check to see if the page is mapped already (no holes) 76 */ 77 if (PageMappedToDisk(page)) 78 goto mapped; 79 80 if (page_has_buffers(page)) { 81 struct buffer_head *bh, *head; 82 int fully_mapped = 1; 83 84 bh = head = page_buffers(page); 85 do { 86 if (!buffer_mapped(bh)) { 87 fully_mapped = 0; 88 break; 89 } 90 } while (bh = bh->b_this_page, bh != head); 91 92 if (fully_mapped) { 93 SetPageMappedToDisk(page); 94 goto mapped; 95 } 96 } 97 unlock_page(page); 98 99 /* 100 * fill hole blocks 101 */ 102 ret = nilfs_transaction_begin(inode->i_sb, &ti, 1); 103 /* never returns -ENOMEM, but may return -ENOSPC */ 104 if (unlikely(ret)) 105 goto out; 106 107 file_update_time(vma->vm_file); 108 ret = block_page_mkwrite(vma, vmf, nilfs_get_block); 109 if (ret) { 110 nilfs_transaction_abort(inode->i_sb); 111 goto out; 112 } 113 nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits)); 114 nilfs_transaction_commit(inode->i_sb); 115 116 mapped: 117 wait_for_stable_page(page); 118 out: 119 sb_end_pagefault(inode->i_sb); 120 return block_page_mkwrite_return(ret); 121 } 122 123 static const struct vm_operations_struct nilfs_file_vm_ops = { 124 .fault = filemap_fault, 125 .map_pages = filemap_map_pages, 126 .page_mkwrite = nilfs_page_mkwrite, 127 }; 128 129 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma) 130 { 131 file_accessed(file); 132 vma->vm_ops = &nilfs_file_vm_ops; 133 return 0; 134 } 135 136 /* 137 * We have mostly NULL's here: the current defaults are ok for 138 * the nilfs filesystem. 139 */ 140 const struct file_operations nilfs_file_operations = { 141 .llseek = generic_file_llseek, 142 .read_iter = generic_file_read_iter, 143 .write_iter = generic_file_write_iter, 144 .unlocked_ioctl = nilfs_ioctl, 145 #ifdef CONFIG_COMPAT 146 .compat_ioctl = nilfs_compat_ioctl, 147 #endif /* CONFIG_COMPAT */ 148 .mmap = nilfs_file_mmap, 149 .open = generic_file_open, 150 /* .release = nilfs_release_file, */ 151 .fsync = nilfs_sync_file, 152 .splice_read = generic_file_splice_read, 153 }; 154 155 const struct inode_operations nilfs_file_inode_operations = { 156 .setattr = nilfs_setattr, 157 .permission = nilfs_permission, 158 .fiemap = nilfs_fiemap, 159 }; 160 161 /* end of file */ 162