file.c (5414B)
1// SPDX-License-Identifier: GPL-2.0 2/* 3 * linux/fs/ext2/file.c 4 * 5 * Copyright (C) 1992, 1993, 1994, 1995 6 * Remy Card (card@masi.ibp.fr) 7 * Laboratoire MASI - Institut Blaise Pascal 8 * Universite Pierre et Marie Curie (Paris VI) 9 * 10 * from 11 * 12 * linux/fs/minix/file.c 13 * 14 * Copyright (C) 1991, 1992 Linus Torvalds 15 * 16 * ext2 fs regular file handling primitives 17 * 18 * 64-bit file support on 64-bit platforms by Jakub Jelinek 19 * (jj@sunsite.ms.mff.cuni.cz) 20 */ 21 22#include <linux/time.h> 23#include <linux/pagemap.h> 24#include <linux/dax.h> 25#include <linux/quotaops.h> 26#include <linux/iomap.h> 27#include <linux/uio.h> 28#include "ext2.h" 29#include "xattr.h" 30#include "acl.h" 31 32#ifdef CONFIG_FS_DAX 33static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) 34{ 35 struct inode *inode = iocb->ki_filp->f_mapping->host; 36 ssize_t ret; 37 38 if (!iov_iter_count(to)) 39 return 0; /* skip atime */ 40 41 inode_lock_shared(inode); 42 ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops); 43 inode_unlock_shared(inode); 44 45 file_accessed(iocb->ki_filp); 46 return ret; 47} 48 49static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) 50{ 51 struct file *file = iocb->ki_filp; 52 struct inode *inode = file->f_mapping->host; 53 ssize_t ret; 54 55 inode_lock(inode); 56 ret = generic_write_checks(iocb, from); 57 if (ret <= 0) 58 goto out_unlock; 59 ret = file_remove_privs(file); 60 if (ret) 61 goto out_unlock; 62 ret = file_update_time(file); 63 if (ret) 64 goto out_unlock; 65 66 ret = dax_iomap_rw(iocb, from, &ext2_iomap_ops); 67 if (ret > 0 && iocb->ki_pos > i_size_read(inode)) { 68 i_size_write(inode, iocb->ki_pos); 69 mark_inode_dirty(inode); 70 } 71 72out_unlock: 73 inode_unlock(inode); 74 if (ret > 0) 75 ret = generic_write_sync(iocb, ret); 76 return ret; 77} 78 79/* 80 * The lock ordering for ext2 DAX fault paths is: 81 * 82 * mmap_lock (MM) 83 * sb_start_pagefault (vfs, freeze) 84 * address_space->invalidate_lock 85 * address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX) 86 * ext2_inode_info->truncate_mutex 87 * 88 * The default page_lock and i_size verification done by non-DAX fault paths 89 * is sufficient because ext2 doesn't support hole punching. 90 */ 91static vm_fault_t ext2_dax_fault(struct vm_fault *vmf) 92{ 93 struct inode *inode = file_inode(vmf->vma->vm_file); 94 vm_fault_t ret; 95 bool write = (vmf->flags & FAULT_FLAG_WRITE) && 96 (vmf->vma->vm_flags & VM_SHARED); 97 98 if (write) { 99 sb_start_pagefault(inode->i_sb); 100 file_update_time(vmf->vma->vm_file); 101 } 102 filemap_invalidate_lock_shared(inode->i_mapping); 103 104 ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, NULL, &ext2_iomap_ops); 105 106 filemap_invalidate_unlock_shared(inode->i_mapping); 107 if (write) 108 sb_end_pagefault(inode->i_sb); 109 return ret; 110} 111 112static const struct vm_operations_struct ext2_dax_vm_ops = { 113 .fault = ext2_dax_fault, 114 /* 115 * .huge_fault is not supported for DAX because allocation in ext2 116 * cannot be reliably aligned to huge page sizes and so pmd faults 117 * will always fail and fail back to regular faults. 118 */ 119 .page_mkwrite = ext2_dax_fault, 120 .pfn_mkwrite = ext2_dax_fault, 121}; 122 123static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) 124{ 125 if (!IS_DAX(file_inode(file))) 126 return generic_file_mmap(file, vma); 127 128 file_accessed(file); 129 vma->vm_ops = &ext2_dax_vm_ops; 130 return 0; 131} 132#else 133#define ext2_file_mmap generic_file_mmap 134#endif 135 136/* 137 * Called when filp is released. This happens when all file descriptors 138 * for a single struct file are closed. Note that different open() calls 139 * for the same file yield different struct file structures. 140 */ 141static int ext2_release_file (struct inode * inode, struct file * filp) 142{ 143 if (filp->f_mode & FMODE_WRITE) { 144 mutex_lock(&EXT2_I(inode)->truncate_mutex); 145 ext2_discard_reservation(inode); 146 mutex_unlock(&EXT2_I(inode)->truncate_mutex); 147 } 148 return 0; 149} 150 151int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) 152{ 153 int ret; 154 struct super_block *sb = file->f_mapping->host->i_sb; 155 156 ret = generic_file_fsync(file, start, end, datasync); 157 if (ret == -EIO) 158 /* We don't really know where the IO error happened... */ 159 ext2_error(sb, __func__, 160 "detected IO error when writing metadata buffers"); 161 return ret; 162} 163 164static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 165{ 166#ifdef CONFIG_FS_DAX 167 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 168 return ext2_dax_read_iter(iocb, to); 169#endif 170 return generic_file_read_iter(iocb, to); 171} 172 173static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 174{ 175#ifdef CONFIG_FS_DAX 176 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 177 return ext2_dax_write_iter(iocb, from); 178#endif 179 return generic_file_write_iter(iocb, from); 180} 181 182const struct file_operations ext2_file_operations = { 183 .llseek = generic_file_llseek, 184 .read_iter = ext2_file_read_iter, 185 .write_iter = ext2_file_write_iter, 186 .unlocked_ioctl = ext2_ioctl, 187#ifdef CONFIG_COMPAT 188 .compat_ioctl = ext2_compat_ioctl, 189#endif 190 .mmap = ext2_file_mmap, 191 .open = dquot_file_open, 192 .release = ext2_release_file, 193 .fsync = ext2_fsync, 194 .get_unmapped_area = thp_get_unmapped_area, 195 .splice_read = generic_file_splice_read, 196 .splice_write = iter_file_splice_write, 197}; 198 199const struct inode_operations ext2_file_inode_operations = { 200 .listxattr = ext2_listxattr, 201 .getattr = ext2_getattr, 202 .setattr = ext2_setattr, 203 .get_acl = ext2_get_acl, 204 .set_acl = ext2_set_acl, 205 .fiemap = ext2_fiemap, 206 .fileattr_get = ext2_fileattr_get, 207 .fileattr_set = ext2_fileattr_set, 208};