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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 "ext4.h"
  25 #include "ext4_jbd2.h"
  26 #include "xattr.h"
  27 #include "acl.h"
  28
  29 /*
  30  * Called when an inode is released. Note that this is different
  31  * from ext4_file_open: open gets called at every open, but release
  32  * gets called only when /all/ the files are closed.
  33  */
  34 static int ext4_release_file(struct inode *inode, struct file *filp)
  35 {
  36         if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
  37                 ext4_alloc_da_blocks(inode);
  38                 EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
  39         }
  40         /* if we are the last writer on the inode, drop the block reservation */
  41         if ((filp->f_mode & FMODE_WRITE) &&
  42                         (atomic_read(&inode->i_writecount) == 1))
  43         {
  44                 down_write(&EXT4_I(inode)->i_data_sem);
  45                 ext4_discard_preallocations(inode);
  46                 up_write(&EXT4_I(inode)->i_data_sem);
  47         }
  48         if (is_dx(inode) && filp->private_data)
  49                 ext4_htree_free_dir_info(filp->private_data);
  50
  51         return 0;
  52 }
  53
  54 static ssize_t
  55 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  56                 unsigned long nr_segs, loff_t pos)
  57 {
  58         struct file *file = iocb->ki_filp;
  59         struct inode *inode = file->f_path.dentry->d_inode;
  60         ssize_t ret;
  61         int err;
  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         ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
  82         /*
  83          * Skip flushing if there was an error, or if nothing was written.
  84          */
  85         if (ret <= 0)
  86                 return ret;
  87
  88         /*
  89          * If the inode is IS_SYNC, or is O_SYNC and we are doing data
  90          * journalling then we need to make sure that we force the transaction
  91          * to disk to keep all metadata uptodate synchronously.
  92          */
  93         if (file->f_flags & O_SYNC) {
  94                 /*
  95                  * If we are non-data-journaled, then the dirty data has
  96                  * already been flushed to backing store by generic_osync_inode,
  97                  * and the inode has been flushed too if there have been any
  98                  * modifications other than mere timestamp updates.
  99                  *
 100                  * Open question --- do we care about flushing timestamps too
 101                  * if the inode is IS_SYNC?
 102                  */
 103                 if (!ext4_should_journal_data(inode))
 104                         return ret;
 105
 106                 goto force_commit;
 107         }
 108
 109         /*
 110          * So we know that there has been no forced data flush.  If the inode
 111          * is marked IS_SYNC, we need to force one ourselves.
 112          */
 113         if (!IS_SYNC(inode))
 114                 return ret;
 115
 116         /*
 117          * Open question #2 --- should we force data to disk here too?  If we
 118          * don't, the only impact is that data=writeback filesystems won't
 119          * flush data to disk automatically on IS_SYNC, only metadata (but
 120          * historically, that is what ext2 has done.)
 121          */
 122
 123 force_commit:
 124         err = ext4_force_commit(inode->i_sb);
 125         if (err)
 126                 return err;
 127         return ret;
 128 }
 129
 130 static struct vm_operations_struct ext4_file_vm_ops = {
 131         .fault          = filemap_fault,
 132         .page_mkwrite   = ext4_page_mkwrite,
 133 };
 134
 135 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 136 {
 137         struct address_space *mapping = file->f_mapping;
 138
 139         if (!mapping->a_ops->readpage)
 140                 return -ENOEXEC;
 141         file_accessed(file);
 142         vma->vm_ops = &ext4_file_vm_ops;
 143         vma->vm_flags |= VM_CAN_NONLINEAR;
 144         return 0;
 145 }
 146
 147 const struct file_operations ext4_file_operations = {
 148         .llseek         = generic_file_llseek,
 149         .read           = do_sync_read,
 150         .write          = do_sync_write,
 151         .aio_read       = generic_file_aio_read,
 152         .aio_write      = ext4_file_write,
 153         .unlocked_ioctl = ext4_ioctl,
 154 #ifdef CONFIG_COMPAT
 155         .compat_ioctl   = ext4_compat_ioctl,
 156 #endif
 157         .mmap           = ext4_file_mmap,
 158         .open           = generic_file_open,
 159         .release        = ext4_release_file,
 160         .fsync          = ext4_sync_file,
 161         .splice_read    = generic_file_splice_read,
 162         .splice_write   = generic_file_splice_write,
 163 };
 164
 165 const struct inode_operations ext4_file_inode_operations = {
 166         .truncate       = ext4_truncate,
 167         .setattr        = ext4_setattr,
 168         .getattr        = ext4_getattr,
 169 #ifdef CONFIG_EXT4_FS_XATTR
 170         .setxattr       = generic_setxattr,
 171         .getxattr       = generic_getxattr,
 172         .listxattr      = ext4_listxattr,
 173         .removexattr    = generic_removexattr,
 174 #endif
 175         .permission     = ext4_permission,
 176         .fallocate      = ext4_fallocate,
 177         .fiemap         = ext4_fiemap,
 178 };
 179