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 = iomap_dax_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 = iomap_dax_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_area_struct *vma, struct vm_fault *vmf) 91 { 92 struct inode *inode = file_inode(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(vma->vm_file); 99 } 100 down_read(&ei->dax_sem); 101 102 ret = iomap_dax_fault(vma, vmf, &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_pmd_fault(struct vm_area_struct *vma, unsigned long addr, 111 pmd_t *pmd, unsigned int flags) 112 { 113 struct inode *inode = file_inode(vma->vm_file); 114 struct ext2_inode_info *ei = EXT2_I(inode); 115 int ret; 116 117 if (flags & FAULT_FLAG_WRITE) { 118 sb_start_pagefault(inode->i_sb); 119 file_update_time(vma->vm_file); 120 } 121 down_read(&ei->dax_sem); 122 123 ret = dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block); 124 125 up_read(&ei->dax_sem); 126 if (flags & FAULT_FLAG_WRITE) 127 sb_end_pagefault(inode->i_sb); 128 return ret; 129 } 130 131 static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma, 132 struct vm_fault *vmf) 133 { 134 struct inode *inode = file_inode(vma->vm_file); 135 struct ext2_inode_info *ei = EXT2_I(inode); 136 loff_t size; 137 int ret; 138 139 sb_start_pagefault(inode->i_sb); 140 file_update_time(vma->vm_file); 141 down_read(&ei->dax_sem); 142 143 /* check that the faulting page hasn't raced with truncate */ 144 size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; 145 if (vmf->pgoff >= size) 146 ret = VM_FAULT_SIGBUS; 147 else 148 ret = dax_pfn_mkwrite(vma, vmf); 149 150 up_read(&ei->dax_sem); 151 sb_end_pagefault(inode->i_sb); 152 return ret; 153 } 154 155 static const struct vm_operations_struct ext2_dax_vm_ops = { 156 .fault = ext2_dax_fault, 157 .pmd_fault = ext2_dax_pmd_fault, 158 .page_mkwrite = ext2_dax_fault, 159 .pfn_mkwrite = ext2_dax_pfn_mkwrite, 160 }; 161 162 static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma) 163 { 164 if (!IS_DAX(file_inode(file))) 165 return generic_file_mmap(file, vma); 166 167 file_accessed(file); 168 vma->vm_ops = &ext2_dax_vm_ops; 169 vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; 170 return 0; 171 } 172 #else 173 #define ext2_file_mmap generic_file_mmap 174 #endif 175 176 /* 177 * Called when filp is released. This happens when all file descriptors 178 * for a single struct file are closed. Note that different open() calls 179 * for the same file yield different struct file structures. 180 */ 181 static int ext2_release_file (struct inode * inode, struct file * filp) 182 { 183 if (filp->f_mode & FMODE_WRITE) { 184 mutex_lock(&EXT2_I(inode)->truncate_mutex); 185 ext2_discard_reservation(inode); 186 mutex_unlock(&EXT2_I(inode)->truncate_mutex); 187 } 188 return 0; 189 } 190 191 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync) 192 { 193 int ret; 194 struct super_block *sb = file->f_mapping->host->i_sb; 195 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping; 196 197 ret = generic_file_fsync(file, start, end, datasync); 198 if (ret == -EIO || test_and_clear_bit(AS_EIO, &mapping->flags)) { 199 /* We don't really know where the IO error happened... */ 200 ext2_error(sb, __func__, 201 "detected IO error when writing metadata buffers"); 202 ret = -EIO; 203 } 204 return ret; 205 } 206 207 static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 208 { 209 #ifdef CONFIG_FS_DAX 210 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 211 return ext2_dax_read_iter(iocb, to); 212 #endif 213 return generic_file_read_iter(iocb, to); 214 } 215 216 static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 217 { 218 #ifdef CONFIG_FS_DAX 219 if (IS_DAX(iocb->ki_filp->f_mapping->host)) 220 return ext2_dax_write_iter(iocb, from); 221 #endif 222 return generic_file_write_iter(iocb, from); 223 } 224 225 const struct file_operations ext2_file_operations = { 226 .llseek = generic_file_llseek, 227 .read_iter = ext2_file_read_iter, 228 .write_iter = ext2_file_write_iter, 229 .unlocked_ioctl = ext2_ioctl, 230 #ifdef CONFIG_COMPAT 231 .compat_ioctl = ext2_compat_ioctl, 232 #endif 233 .mmap = ext2_file_mmap, 234 .open = dquot_file_open, 235 .release = ext2_release_file, 236 .fsync = ext2_fsync, 237 .get_unmapped_area = thp_get_unmapped_area, 238 .splice_read = generic_file_splice_read, 239 .splice_write = iter_file_splice_write, 240 }; 241 242 const struct inode_operations ext2_file_inode_operations = { 243 #ifdef CONFIG_EXT2_FS_XATTR 244 .listxattr = ext2_listxattr, 245 #endif 246 .setattr = ext2_setattr, 247 .get_acl = ext2_get_acl, 248 .set_acl = ext2_set_acl, 249 .fiemap = ext2_fiemap, 250 }; 251