1 /* 2 * linux/fs/ext2/file.c 3 * 4 * Copyright (C) 1992, 1993, 1994, 1995 5 * Remy Card (card@masi.ibp.fr) 6 * Laboratoire MASI - Institut Blaise Pascal 7 * Universite Pierre et Marie Curie (Paris VI) 8 * 9 * from 10 * 11 * linux/fs/minix/file.c 12 * 13 * Copyright (C) 1991, 1992 Linus Torvalds 14 * 15 * ext2 fs regular file handling primitives 16 * 17 * 64-bit file support on 64-bit platforms by Jakub Jelinek 18 * (jj@sunsite.ms.mff.cuni.cz) 19 */ 20 21 #include <linux/time.h> 22 #include <linux/pagemap.h> 23 #include <linux/dax.h> 24 #include <linux/quotaops.h> 25 #include <linux/iomap.h> 26 #include <linux/uio.h> 27 #include "ext2.h" 28 #include "xattr.h" 29 #include "acl.h" 30 31 #ifdef CONFIG_FS_DAX 32 static ssize_t ext2_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) 33 { 34 struct inode *inode = iocb->ki_filp->f_mapping->host; 35 ssize_t ret; 36 37 if (!iov_iter_count(to)) 38 return 0; /* skip atime */ 39 40 inode_lock_shared(inode); 41 ret = dax_iomap_rw(iocb, to, &ext2_iomap_ops); 42 inode_unlock_shared(inode); 43 44 file_accessed(iocb->ki_filp); 45 return ret; 46 } 47 48 static ssize_t ext2_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) 49 { 50 struct file *file = iocb->ki_filp; 51 struct inode *inode = file->f_mapping->host; 52 ssize_t ret; 53 54 inode_lock(inode); 55 ret = generic_write_checks(iocb, from); 56 if (ret <= 0) 57 goto out_unlock; 58 ret = file_remove_privs(file); 59 if (ret) 60 goto out_unlock; 61 ret = file_update_time(file); 62 if (ret) 63 goto out_unlock; 64 65 ret = dax_iomap_rw(iocb, from, &ext2_iomap_ops); 66 if (ret > 0 && iocb->ki_pos > i_size_read(inode)) { 67 i_size_write(inode, iocb->ki_pos); 68 mark_inode_dirty(inode); 69 } 70 71 out_unlock: 72 inode_unlock(inode); 73 if (ret > 0) 74 ret = generic_write_sync(iocb, ret); 75 return ret; 76 } 77 78 /* 79 * The lock ordering for ext2 DAX fault paths is: 80 * 81 * mmap_sem (MM) 82 * sb_start_pagefault (vfs, freeze) 83 * ext2_inode_info->dax_sem 84 * address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX) 85 * ext2_inode_info->truncate_mutex 86 * 87 * The default page_lock and i_size verification done by non-DAX fault paths 88 * is sufficient because ext2 doesn't support hole punching. 89 */ 90 static int ext2_dax_fault(struct vm_fault *vmf) 91 { 92 struct inode *inode = file_inode(vmf->vma->vm_file); 93 struct ext2_inode_info *ei = EXT2_I(inode); 94 int ret; 95 96 if (vmf->flags & FAULT_FLAG_WRITE) { 97 sb_start_pagefault(inode->i_sb); 98 file_update_time(vmf->vma->vm_file); 99 } 100 down_read(&ei->dax_sem); 101 102 ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &ext2_iomap_ops); 103 104 up_read(&ei->dax_sem); 105 if (vmf->flags & FAULT_FLAG_WRITE) 106 sb_end_pagefault(inode->i_sb); 107 return ret; 108 } 109 110 static int ext2_dax_pfn_mkwrite(struct vm_fault *vmf) 111 { 112 struct inode *inode = file_inode(vmf->vma->vm_file); 113 struct ext2_inode_info *ei = EXT2_I(inode); 114 loff_t size; 115 int ret; 116 117 sb_start_pagefault(inode->i_sb); 118 file_update_time(vmf->vma->vm_file); 119 down_read(&ei->dax_sem); 120 121 /* check that the faulting page hasn't raced with truncate */ 122 size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; 123 if (vmf->pgoff >= size) 124 ret = VM_FAULT_SIGBUS; 125 else 126 ret = dax_pfn_mkwrite(vmf); 127 128 up_read(&ei->dax_sem); 129 sb_end_pagefault(inode->i_sb); 130 return ret; 131 } 132 133 static const struct vm_operations_struct ext2_dax_vm_ops = { 134 .fault = ext2_dax_fault, 135 /* 136 * .huge_fault is not supported for DAX because allocation in ext2 137 * cannot be reliably aligned to huge page sizes and so pmd faults 138 * will always fail and fail back to regular faults. 139 */ 140 .page_mkwrite = ext2_dax_fault, 141 .pfn_mkwrite = ext2_dax_pfn_mkwrite, 142 }; 143 144 static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) 145 { 146 if (!IS_DAX(file_inode(file))) 147 return generic_file_mmap(file, vma); 148 149 file_accessed(file); 150 vma->vm_ops = &ext2_dax_vm_ops; 151 vma->vm_flags |= VM_MIXEDMAP; 152 return 0; 153 } 154 #else 155 #define ext2_file_mmap generic_file_mmap 156 #endif 157 158 /* 159 * Called when filp is released. This happens when all file descriptors 160 * for a single struct file are closed. Note that different open() calls 161 * for the same file yield different struct file structures. 162 */ 163 static int ext2_release_file (struct inode * inode, struct file * filp) 164 { 165 if (filp->f_mode & FMODE_WRITE) { 166 mutex_lock(&EXT2_I(inode)->truncate_mutex); 167 ext2_discard_reservation(inode); 168 mutex_unlock(&EXT2_I(inode)->truncate_mutex); 169 } 170 return 0; 171 } 172 173 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) 174 { 175 int ret; 176 struct super_block *sb = file->f_mapping->host->i_sb; 177 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 178 179 ret = generic_file_fsync(file, start, end, datasync); 180 if (ret == -EIO || test_and_clear_bit(AS_EIO, &mapping->flags)) { 181 /* We don't really know where the IO error happened... */ 182 ext2_error(sb, __func__, 183 "detected IO error when writing metadata buffers"); 184 ret = -EIO; 185 } 186 return ret; 187 } 188 189 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 190 { 191 #ifdef CONFIG_FS_DAX 192 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 193 return ext2_dax_read_iter(iocb, to); 194 #endif 195 return generic_file_read_iter(iocb, to); 196 } 197 198 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 199 { 200 #ifdef CONFIG_FS_DAX 201 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 202 return ext2_dax_write_iter(iocb, from); 203 #endif 204 return generic_file_write_iter(iocb, from); 205 } 206 207 const struct file_operations ext2_file_operations = { 208 .llseek = generic_file_llseek, 209 .read_iter = ext2_file_read_iter, 210 .write_iter = ext2_file_write_iter, 211 .unlocked_ioctl = ext2_ioctl, 212 #ifdef CONFIG_COMPAT 213 .compat_ioctl = ext2_compat_ioctl, 214 #endif 215 .mmap = ext2_file_mmap, 216 .open = dquot_file_open, 217 .release = ext2_release_file, 218 .fsync = ext2_fsync, 219 .get_unmapped_area = thp_get_unmapped_area, 220 .splice_read = generic_file_splice_read, 221 .splice_write = iter_file_splice_write, 222 }; 223 224 const struct inode_operations ext2_file_inode_operations = { 225 #ifdef CONFIG_EXT2_FS_XATTR 226 .listxattr = ext2_listxattr, 227 #endif 228 .setattr = ext2_setattr, 229 .get_acl = ext2_get_acl, 230 .set_acl = ext2_set_acl, 231 .fiemap = ext2_fiemap, 232 }; 233