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 33 static 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 49 static 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 72 out_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_sem (MM) 83 * sb_start_pagefault (vfs, freeze) 84 * ext2_inode_info->dax_sem 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 */ 91 static vm_fault_t ext2_dax_fault(struct vm_fault *vmf) 92 { 93 struct inode *inode = file_inode(vmf->vma->vm_file); 94 struct ext2_inode_info *ei = EXT2_I(inode); 95 vm_fault_t ret; 96 97 if (vmf->flags & FAULT_FLAG_WRITE) { 98 sb_start_pagefault(inode->i_sb); 99 file_update_time(vmf->vma->vm_file); 100 } 101 down_read(&ei->dax_sem); 102 103 ret = dax_iomap_fault(vmf, PE_SIZE_PTE, NULL, NULL, &ext2_iomap_ops); 104 105 up_read(&ei->dax_sem); 106 if (vmf->flags & FAULT_FLAG_WRITE) 107 sb_end_pagefault(inode->i_sb); 108 return ret; 109 } 110 111 static const struct vm_operations_struct ext2_dax_vm_ops = { 112 .fault = ext2_dax_fault, 113 /* 114 * .huge_fault is not supported for DAX because allocation in ext2 115 * cannot be reliably aligned to huge page sizes and so pmd faults 116 * will always fail and fail back to regular faults. 117 */ 118 .page_mkwrite = ext2_dax_fault, 119 .pfn_mkwrite = ext2_dax_fault, 120 }; 121 122 static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) 123 { 124 if (!IS_DAX(file_inode(file))) 125 return generic_file_mmap(file, vma); 126 127 file_accessed(file); 128 vma->vm_ops = &ext2_dax_vm_ops; 129 return 0; 130 } 131 #else 132 #define ext2_file_mmap generic_file_mmap 133 #endif 134 135 /* 136 * Called when filp is released. This happens when all file descriptors 137 * for a single struct file are closed. Note that different open() calls 138 * for the same file yield different struct file structures. 139 */ 140 static int ext2_release_file (struct inode * inode, struct file * filp) 141 { 142 if (filp->f_mode & FMODE_WRITE) { 143 mutex_lock(&EXT2_I(inode)->truncate_mutex); 144 ext2_discard_reservation(inode); 145 mutex_unlock(&EXT2_I(inode)->truncate_mutex); 146 } 147 return 0; 148 } 149 150 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) 151 { 152 int ret; 153 struct super_block *sb = file->f_mapping->host->i_sb; 154 155 ret = generic_file_fsync(file, start, end, datasync); 156 if (ret == -EIO) 157 /* We don't really know where the IO error happened... */ 158 ext2_error(sb, __func__, 159 "detected IO error when writing metadata buffers"); 160 return ret; 161 } 162 163 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 164 { 165 #ifdef CONFIG_FS_DAX 166 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 167 return ext2_dax_read_iter(iocb, to); 168 #endif 169 return generic_file_read_iter(iocb, to); 170 } 171 172 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 173 { 174 #ifdef CONFIG_FS_DAX 175 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 176 return ext2_dax_write_iter(iocb, from); 177 #endif 178 return generic_file_write_iter(iocb, from); 179 } 180 181 const struct file_operations ext2_file_operations = { 182 .llseek = generic_file_llseek, 183 .read_iter = ext2_file_read_iter, 184 .write_iter = ext2_file_write_iter, 185 .unlocked_ioctl = ext2_ioctl, 186 #ifdef CONFIG_COMPAT 187 .compat_ioctl = ext2_compat_ioctl, 188 #endif 189 .mmap = ext2_file_mmap, 190 .open = dquot_file_open, 191 .release = ext2_release_file, 192 .fsync = ext2_fsync, 193 .get_unmapped_area = thp_get_unmapped_area, 194 .splice_read = generic_file_splice_read, 195 .splice_write = iter_file_splice_write, 196 }; 197 198 const struct inode_operations ext2_file_inode_operations = { 199 #ifdef CONFIG_EXT2_FS_XATTR 200 .listxattr = ext2_listxattr, 201 #endif 202 .setattr = ext2_setattr, 203 .get_acl = ext2_get_acl, 204 .set_acl = ext2_set_acl, 205 .fiemap = ext2_fiemap, 206 }; 207