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   1 /*
   2  *  linux/fs/ext4/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  *  ext4 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/fs.h>
  23 #include <linux/jbd2.h>
  24 #include <linux/mount.h>
  25 #include <linux/path.h>
  26 #include "ext4.h"
  27 #include "ext4_jbd2.h"
  28 #include "xattr.h"
  29 #include "acl.h"
  30
  31 /*
  32  * Called when an inode is released. Note that this is different
  33  * from ext4_file_open: open gets called at every open, but release
  34  * gets called only when /all/ the files are closed.
  35  */
  36 static int ext4_release_file(struct inode *inode, struct file *filp)
  37 {
  38         if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
  39                 ext4_alloc_da_blocks(inode);
  40                 EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
  41         }
  42         /* if we are the last writer on the inode, drop the block reservation */
  43         if ((filp->f_mode & FMODE_WRITE) &&
  44                         (atomic_read(&inode->i_writecount) == 1) &&
  45                         !EXT4_I(inode)->i_reserved_data_blocks)
  46         {
  47                 down_write(&EXT4_I(inode)->i_data_sem);
  48                 ext4_discard_preallocations(inode);
  49                 up_write(&EXT4_I(inode)->i_data_sem);
  50         }
  51         if (is_dx(inode) && filp->private_data)
  52                 ext4_htree_free_dir_info(filp->private_data);
  53
  54         return 0;
  55 }
  56
  57 static ssize_t
  58 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  59                 unsigned long nr_segs, loff_t pos)
  60 {
  61         struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
  62
  63         /*
  64          * If we have encountered a bitmap-format file, the size limit
  65          * is smaller than s_maxbytes, which is for extent-mapped files.
  66          */
  67
  68         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
  69                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  70                 size_t length = iov_length(iov, nr_segs);
  71
  72                 if (pos > sbi->s_bitmap_maxbytes)
  73                         return -EFBIG;
  74
  75                 if (pos + length > sbi->s_bitmap_maxbytes) {
  76                         nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
  77                                               sbi->s_bitmap_maxbytes - pos);
  78                 }
  79         }
  80
  81         return generic_file_aio_write(iocb, iov, nr_segs, pos);
  82 }
  83
  84 static const struct vm_operations_struct ext4_file_vm_ops = {
  85         .fault          = filemap_fault,
  86         .page_mkwrite   = ext4_page_mkwrite,
  87 };
  88
  89 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
  90 {
  91         struct address_space *mapping = file->f_mapping;
  92
  93         if (!mapping->a_ops->readpage)
  94                 return -ENOEXEC;
  95         file_accessed(file);
  96         vma->vm_ops = &ext4_file_vm_ops;
  97         vma->vm_flags |= VM_CAN_NONLINEAR;
  98         return 0;
  99 }
 100
 101 static int ext4_file_open(struct inode * inode, struct file * filp)
 102 {
 103         struct super_block *sb = inode->i_sb;
 104         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 105         struct vfsmount *mnt = filp->f_path.mnt;
 106         struct path path;
 107         char buf[64], *cp;
 108
 109         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 110                      !(sb->s_flags & MS_RDONLY))) {
 111                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 112                 /*
 113                  * Sample where the filesystem has been mounted and
 114                  * store it in the superblock for sysadmin convenience
 115                  * when trying to sort through large numbers of block
 116                  * devices or filesystem images.
 117                  */
 118                 memset(buf, 0, sizeof(buf));
 119                 path.mnt = mnt;
 120                 path.dentry = mnt->mnt_root;
 121                 cp = d_path(&path, buf, sizeof(buf));
 122                 if (!IS_ERR(cp)) {
 123                         memcpy(sbi->s_es->s_last_mounted, cp,
 124                                sizeof(sbi->s_es->s_last_mounted));
 125                         sb->s_dirt = 1;
 126                 }
 127         }
 128         return generic_file_open(inode, filp);
 129 }
 130
 131 const struct file_operations ext4_file_operations = {
 132         .llseek         = generic_file_llseek,
 133         .read           = do_sync_read,
 134         .write          = do_sync_write,
 135         .aio_read       = generic_file_aio_read,
 136         .aio_write      = ext4_file_write,
 137         .unlocked_ioctl = ext4_ioctl,
 138 #ifdef CONFIG_COMPAT
 139         .compat_ioctl   = ext4_compat_ioctl,
 140 #endif
 141         .mmap           = ext4_file_mmap,
 142         .open           = ext4_file_open,
 143         .release        = ext4_release_file,
 144         .fsync          = ext4_sync_file,
 145         .splice_read    = generic_file_splice_read,
 146         .splice_write   = generic_file_splice_write,
 147 };
 148
 149 const struct inode_operations ext4_file_inode_operations = {
 150         .truncate       = ext4_truncate,
 151         .setattr        = ext4_setattr,
 152         .getattr        = ext4_getattr,
 153 #ifdef CONFIG_EXT4_FS_XATTR
 154         .setxattr       = generic_setxattr,
 155         .getxattr       = generic_getxattr,
 156         .listxattr      = ext4_listxattr,
 157         .removexattr    = generic_removexattr,
 158 #endif
 159         .check_acl      = ext4_check_acl,
 160         .fallocate      = ext4_fallocate,
 161         .fiemap         = ext4_fiemap,
 162 };
 163