LXR linux/fs/ext4/file.c

   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 */
  37static int ext4_release_file(struct inode *inode, struct file *filp)
  38{
  39        if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
  40                ext4_alloc_da_blocks(inode);
  41                ext4_clear_inode_state(inode, 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
  58static ssize_t
  59ext4_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_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
  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
  85static const struct vm_operations_struct ext4_file_vm_ops = {
  86        .fault          = filemap_fault,
  87        .page_mkwrite   = ext4_page_mkwrite,
  88};
  89
  90static 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
 102static 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;
 121                path.dentry = mnt->mnt_root;
 122                cp = d_path(&path, buf, sizeof(buf));
 123                if (!IS_ERR(cp)) {
 124                        memcpy(sbi->s_es->s_last_mounted, cp,
 125                               sizeof(sbi->s_es->s_last_mounted));
 126                        sb->s_dirt = 1;
 127                }
 128        }
 129        return dquot_file_open(inode, filp);
 130}
 131
 132const struct file_operations ext4_file_operations = {
 133        .llseek         = generic_file_llseek,
 134        .read           = do_sync_read,
 135        .write          = do_sync_write,
 136        .aio_read       = generic_file_aio_read,
 137        .aio_write      = ext4_file_write,
 138        .unlocked_ioctl = ext4_ioctl,
 139#ifdef CONFIG_COMPAT
 140        .compat_ioctl   = ext4_compat_ioctl,
 141#endif
 142        .mmap           = ext4_file_mmap,
 143        .open           = ext4_file_open,
 144        .release        = ext4_release_file,
 145        .fsync          = ext4_sync_file,
 146        .splice_read    = generic_file_splice_read,
 147        .splice_write   = generic_file_splice_write,
 148};
 149
 150const struct inode_operations ext4_file_inode_operations = {
 151        .truncate       = ext4_truncate,
 152        .setattr        = ext4_setattr,
 153        .getattr        = ext4_getattr,
 154#ifdef CONFIG_EXT4_FS_XATTR
 155        .setxattr       = generic_setxattr,
 156        .getxattr       = generic_getxattr,
 157        .listxattr      = ext4_listxattr,
 158        .removexattr    = generic_removexattr,
 159#endif
 160        .check_acl      = ext4_check_acl,
 161        .fallocate      = ext4_fallocate,
 162        .fiemap         = ext4_fiemap,
 163};
 164
 165