LXR linux/fs/nilfs2/file.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * file.c - NILFS regular file handling primitives including fsync().
   4 *
   5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6 *
   7 * Written by Amagai Yoshiji and Ryusuke Konishi.
   8 */
   9
  10#include <linux/fs.h>
  11#include <linux/mm.h>
  12#include <linux/writeback.h>
  13#include "nilfs.h"
  14#include "segment.h"
  15
  16int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
  17{
  18        /*
  19         * Called from fsync() system call
  20         * This is the only entry point that can catch write and synch
  21         * timing for both data blocks and intermediate blocks.
  22         *
  23         * This function should be implemented when the writeback function
  24         * will be implemented.
  25         */
  26        struct the_nilfs *nilfs;
  27        struct inode *inode = file->f_mapping->host;
  28        int err = 0;
  29
  30        if (nilfs_inode_dirty(inode)) {
  31                if (datasync)
  32                        err = nilfs_construct_dsync_segment(inode->i_sb, inode,
  33                                                            start, end);
  34                else
  35                        err = nilfs_construct_segment(inode->i_sb);
  36        }
  37
  38        nilfs = inode->i_sb->s_fs_info;
  39        if (!err)
  40                err = nilfs_flush_device(nilfs);
  41
  42        return err;
  43}
  44
  45static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
  46{
  47        struct vm_area_struct *vma = vmf->vma;
  48        struct page *page = vmf->page;
  49        struct inode *inode = file_inode(vma->vm_file);
  50        struct nilfs_transaction_info ti;
  51        int ret = 0;
  52
  53        if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
  54                return VM_FAULT_SIGBUS; /* -ENOSPC */
  55
  56        sb_start_pagefault(inode->i_sb);
  57        lock_page(page);
  58        if (page->mapping != inode->i_mapping ||
  59            page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  60                unlock_page(page);
  61                ret = -EFAULT;  /* make the VM retry the fault */
  62                goto out;
  63        }
  64
  65        /*
  66         * check to see if the page is mapped already (no holes)
  67         */
  68        if (PageMappedToDisk(page))
  69                goto mapped;
  70
  71        if (page_has_buffers(page)) {
  72                struct buffer_head *bh, *head;
  73                int fully_mapped = 1;
  74
  75                bh = head = page_buffers(page);
  76                do {
  77                        if (!buffer_mapped(bh)) {
  78                                fully_mapped = 0;
  79                                break;
  80                        }
  81                } while (bh = bh->b_this_page, bh != head);
  82
  83                if (fully_mapped) {
  84                        SetPageMappedToDisk(page);
  85                        goto mapped;
  86                }
  87        }
  88        unlock_page(page);
  89
  90        /*
  91         * fill hole blocks
  92         */
  93        ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
  94        /* never returns -ENOMEM, but may return -ENOSPC */
  95        if (unlikely(ret))
  96                goto out;
  97
  98        file_update_time(vma->vm_file);
  99        ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 100        if (ret) {
 101                nilfs_transaction_abort(inode->i_sb);
 102                goto out;
 103        }
 104        nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
 105        nilfs_transaction_commit(inode->i_sb);
 106
 107 mapped:
 108        wait_for_stable_page(page);
 109 out:
 110        sb_end_pagefault(inode->i_sb);
 111        return block_page_mkwrite_return(ret);
 112}
 113
 114static const struct vm_operations_struct nilfs_file_vm_ops = {
 115        .fault          = filemap_fault,
 116        .map_pages      = filemap_map_pages,
 117        .page_mkwrite   = nilfs_page_mkwrite,
 118};
 119
 120static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 121{
 122        file_accessed(file);
 123        vma->vm_ops = &nilfs_file_vm_ops;
 124        return 0;
 125}
 126
 127/*
 128 * We have mostly NULL's here: the current defaults are ok for
 129 * the nilfs filesystem.
 130 */
 131const struct file_operations nilfs_file_operations = {
 132        .llseek         = generic_file_llseek,
 133        .read_iter      = generic_file_read_iter,
 134        .write_iter     = generic_file_write_iter,
 135        .unlocked_ioctl = nilfs_ioctl,
 136#ifdef CONFIG_COMPAT
 137        .compat_ioctl   = nilfs_compat_ioctl,
 138#endif  /* CONFIG_COMPAT */
 139        .mmap           = nilfs_file_mmap,
 140        .open           = generic_file_open,
 141        /* .release     = nilfs_release_file, */
 142        .fsync          = nilfs_sync_file,
 143        .splice_read    = generic_file_splice_read,
 144};
 145
 146const struct inode_operations nilfs_file_inode_operations = {
 147        .setattr        = nilfs_setattr,
 148        .permission     = nilfs_permission,
 149        .fiemap         = nilfs_fiemap,
 150};
 151
 152/* end of file */
 153