kernel/fs/ext2/file.c

   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 "ext2.h"
  26 #include "xattr.h"
  27 #include "acl.h"
  28
  29 #ifdef CONFIG_FS_DAX
  30 /*
  31  * The lock ordering for ext2 DAX fault paths is:
  32  *
  33  * mmap_sem (MM)
  34  *   sb_start_pagefault (vfs, freeze)
  35  *     ext2_inode_info->dax_sem
  36  *       address_space->i_mmap_rwsem or page_lock (mutually exclusive in DAX)
  37  *         ext2_inode_info->truncate_mutex
  38  *
  39  * The default page_lock and i_size verification done by non-DAX fault paths
  40  * is sufficient because ext2 doesn't support hole punching.
  41  */
  42 static int ext2_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
  43 {
  44         struct inode *inode = file_inode(vma->vm_file);
  45         struct ext2_inode_info *ei = EXT2_I(inode);
  46         int ret;
  47
  48         if (vmf->flags & FAULT_FLAG_WRITE) {
  49                 sb_start_pagefault(inode->i_sb);
  50                 file_update_time(vma->vm_file);
  51         }
  52         down_read(&ei->dax_sem);
  53
  54         ret = __dax_fault(vma, vmf, ext2_get_block, NULL);
  55
  56         up_read(&ei->dax_sem);
  57         if (vmf->flags & FAULT_FLAG_WRITE)
  58                 sb_end_pagefault(inode->i_sb);
  59         return ret;
  60 }
  61
  62 static int ext2_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
  63                                                 pmd_t *pmd, unsigned int flags)
  64 {
  65         struct inode *inode = file_inode(vma->vm_file);
  66         struct ext2_inode_info *ei = EXT2_I(inode);
  67         int ret;
  68
  69         if (flags & FAULT_FLAG_WRITE) {
  70                 sb_start_pagefault(inode->i_sb);
  71                 file_update_time(vma->vm_file);
  72         }
  73         down_read(&ei->dax_sem);
  74
  75         ret = __dax_pmd_fault(vma, addr, pmd, flags, ext2_get_block, NULL);
  76
  77         up_read(&ei->dax_sem);
  78         if (flags & FAULT_FLAG_WRITE)
  79                 sb_end_pagefault(inode->i_sb);
  80         return ret;
  81 }
  82
  83 static int ext2_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
  84 {
  85         struct inode *inode = file_inode(vma->vm_file);
  86         struct ext2_inode_info *ei = EXT2_I(inode);
  87         int ret;
  88
  89         sb_start_pagefault(inode->i_sb);
  90         file_update_time(vma->vm_file);
  91         down_read(&ei->dax_sem);
  92
  93         ret = __dax_mkwrite(vma, vmf, ext2_get_block, NULL);
  94
  95         up_read(&ei->dax_sem);
  96         sb_end_pagefault(inode->i_sb);
  97         return ret;
  98 }
  99
 100 static int ext2_dax_pfn_mkwrite(struct vm_area_struct *vma,
 101                 struct vm_fault *vmf)
 102 {
 103         struct inode *inode = file_inode(vma->vm_file);
 104         struct ext2_inode_info *ei = EXT2_I(inode);
 105         int ret = VM_FAULT_NOPAGE;
 106         loff_t size;
 107
 108         sb_start_pagefault(inode->i_sb);
 109         file_update_time(vma->vm_file);
 110         down_read(&ei->dax_sem);
 111
 112         /* check that the faulting page hasn't raced with truncate */
 113         size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT;
 114         if (vmf->pgoff >= size)
 115                 ret = VM_FAULT_SIGBUS;
 116
 117         up_read(&ei->dax_sem);
 118         sb_end_pagefault(inode->i_sb);
 119         return ret;
 120 }
 121
 122 static const struct vm_operations_struct ext2_dax_vm_ops = {
 123         .fault          = ext2_dax_fault,
 124         .pmd_fault      = ext2_dax_pmd_fault,
 125         .page_mkwrite   = ext2_dax_mkwrite,
 126         .pfn_mkwrite    = ext2_dax_pfn_mkwrite,
 127 };
 128
 129 static int ext2_file_mmap(struct file *file, struct vm_area_struct *vma)
 130 {
 131         if (!IS_DAX(file_inode(file)))
 132                 return generic_file_mmap(file, vma);
 133
 134         file_accessed(file);
 135         vma->vm_ops = &ext2_dax_vm_ops;
 136         vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE;
 137         return 0;
 138 }
 139 #else
 140 #define ext2_file_mmap  generic_file_mmap
 141 #endif
 142
 143 /*
 144  * Called when filp is released. This happens when all file descriptors
 145  * for a single struct file are closed. Note that different open() calls
 146  * for the same file yield different struct file structures.
 147  */
 148 static int ext2_release_file (struct inode * inode, struct file * filp)
 149 {
 150         if (filp->f_mode & FMODE_WRITE) {
 151                 mutex_lock(&EXT2_I(inode)->truncate_mutex);
 152                 ext2_discard_reservation(inode);
 153                 mutex_unlock(&EXT2_I(inode)->truncate_mutex);
 154         }
 155         return 0;
 156 }
 157
 158 int ext2_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 159 {
 160         int ret;
 161         struct super_block *sb = file->f_mapping->host->i_sb;
 162         struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
 163
 164         ret = generic_file_fsync(file, start, end, datasync);
 165         if (ret == -EIO || test_and_clear_bit(AS_EIO, &mapping->flags)) {
 166                 /* We don't really know where the IO error happened... */
 167                 ext2_error(sb, __func__,
 168                            "detected IO error when writing metadata buffers");
 169                 ret = -EIO;
 170         }
 171         return ret;
 172 }
 173
 174 /*
 175  * We have mostly NULL's here: the current defaults are ok for
 176  * the ext2 filesystem.
 177  */
 178 const struct file_operations ext2_file_operations = {
 179         .llseek         = generic_file_llseek,
 180         .read_iter      = generic_file_read_iter,
 181         .write_iter     = generic_file_write_iter,
 182         .unlocked_ioctl = ext2_ioctl,
 183 #ifdef CONFIG_COMPAT
 184         .compat_ioctl   = ext2_compat_ioctl,
 185 #endif
 186         .mmap           = ext2_file_mmap,
 187         .open           = dquot_file_open,
 188         .release        = ext2_release_file,
 189         .fsync          = ext2_fsync,
 190         .splice_read    = generic_file_splice_read,
 191         .splice_write   = iter_file_splice_write,
 192 };
 193
 194 const struct inode_operations ext2_file_inode_operations = {
 195 #ifdef CONFIG_EXT2_FS_XATTR
 196         .setxattr       = generic_setxattr,
 197         .getxattr       = generic_getxattr,
 198         .listxattr      = ext2_listxattr,
 199         .removexattr    = generic_removexattr,
 200 #endif
 201         .setattr        = ext2_setattr,
 202         .get_acl        = ext2_get_acl,
 203         .set_acl        = ext2_set_acl,
 204         .fiemap         = ext2_fiemap,
 205 };