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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 <linux/quotaops.h>
  27 #include "ext4.h"
  28 #include "ext4_jbd2.h"
  29 #include "xattr.h"
  30 #include "acl.h"
  31
  32 /*
  33  * Called when an inode is released. Note that this is different
  34  * from ext4_file_open: open gets called at every open, but release
  35  * gets called only when /all/ the files are closed.
  36  */
  37 static int ext4_release_file(struct inode *inode, struct file *filp)
  38 {
  39         if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
  40                 ext4_alloc_da_blocks(inode);
  41                 EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
  42         }
  43         /* if we are the last writer on the inode, drop the block reservation */
  44         if ((filp->f_mode & FMODE_WRITE) &&
  45                         (atomic_read(&inode->i_writecount) == 1) &&
  46                         !EXT4_I(inode)->i_reserved_data_blocks)
  47         {
  48                 down_write(&EXT4_I(inode)->i_data_sem);
  49                 ext4_discard_preallocations(inode);
  50                 up_write(&EXT4_I(inode)->i_data_sem);
  51         }
  52         if (is_dx(inode) && filp->private_data)
  53                 ext4_htree_free_dir_info(filp->private_data);
  54
  55         return 0;
  56 }
  57
  58 static ssize_t
  59 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  60                 unsigned long nr_segs, loff_t pos)
  61 {
  62         struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
  63
  64         /*
  65          * If we have encountered a bitmap-format file, the size limit
  66          * is smaller than s_maxbytes, which is for extent-mapped files.
  67          */
  68
  69         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
  70                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  71                 size_t length = iov_length(iov, nr_segs);
  72
  73                 if (pos > sbi->s_bitmap_maxbytes)
  74                         return -EFBIG;
  75
  76                 if (pos + length > sbi->s_bitmap_maxbytes) {
  77                         nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
  78                                               sbi->s_bitmap_maxbytes - pos);
  79                 }
  80         }
  81
  82         return generic_file_aio_write(iocb, iov, nr_segs, pos);
  83 }
  84
  85 static const struct vm_operations_struct ext4_file_vm_ops = {
  86         .fault          = filemap_fault,
  87         .page_mkwrite   = ext4_page_mkwrite,
  88 };
  89
  90 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
  91 {
  92         struct address_space *mapping = file->f_mapping;
  93
  94         if (!mapping->a_ops->readpage)
  95                 return -ENOEXEC;
  96         file_accessed(file);
  97         vma->vm_ops = &ext4_file_vm_ops;
  98         vma->vm_flags |= VM_CAN_NONLINEAR;
  99         return 0;
 100 }
 101
 102 static int ext4_file_open(struct inode * inode, struct file * filp)
 103 {
 104         struct super_block *sb = inode->i_sb;
 105         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 106         struct vfsmount *mnt = filp->f_path.mnt;
 107         struct path path;
 108         char buf[64], *cp;
 109
 110         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 111                      !(sb->s_flags & MS_RDONLY))) {
 112                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 113                 /*
 114                  * Sample where the filesystem has been mounted and
 115                  * store it in the superblock for sysadmin convenience
 116                  * when trying to sort through large numbers of block
 117                  * devices or filesystem images.
 118                  */
 119                 memset(buf, 0, sizeof(buf));
 120                 path.mnt = mnt->mnt_parent;
 121                 path.dentry = mnt->mnt_mountpoint;
 122                 path_get(&path);
 123                 cp = d_path(&path, buf, sizeof(buf));
 124                 path_put(&path);
 125                 if (!IS_ERR(cp)) {
 126                         memcpy(sbi->s_es->s_last_mounted, cp,
 127                                sizeof(sbi->s_es->s_last_mounted));
 128                         sb->s_dirt = 1;
 129                 }
 130         }
 131         return dquot_file_open(inode, filp);
 132 }
 133
 134 const struct file_operations ext4_file_operations = {
 135         .llseek         = generic_file_llseek,
 136         .read           = do_sync_read,
 137         .write          = do_sync_write,
 138         .aio_read       = generic_file_aio_read,
 139         .aio_write      = ext4_file_write,
 140         .unlocked_ioctl = ext4_ioctl,
 141 #ifdef CONFIG_COMPAT
 142         .compat_ioctl   = ext4_compat_ioctl,
 143 #endif
 144         .mmap           = ext4_file_mmap,
 145         .open           = ext4_file_open,
 146         .release        = ext4_release_file,
 147         .fsync          = ext4_sync_file,
 148         .splice_read    = generic_file_splice_read,
 149         .splice_write   = generic_file_splice_write,
 150 };
 151
 152 const struct inode_operations ext4_file_inode_operations = {
 153         .truncate       = ext4_truncate,
 154         .setattr        = ext4_setattr,
 155         .getattr        = ext4_getattr,
 156 #ifdef CONFIG_EXT4_FS_XATTR
 157         .setxattr       = generic_setxattr,
 158         .getxattr       = generic_getxattr,
 159         .listxattr      = ext4_listxattr,
 160         .removexattr    = generic_removexattr,
 161 #endif
 162         .check_acl      = ext4_check_acl,
 163         .fallocate      = ext4_fallocate,
 164         .fiemap         = ext4_fiemap,
 165 };
 166