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/ext4_fs.h>
  25 #include <linux/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 we are the last writer on the inode, drop the block reservation */
  37         if ((filp->f_mode & FMODE_WRITE) &&
  38                         (atomic_read(&inode->i_writecount) == 1))
  39         {
  40                 mutex_lock(&EXT4_I(inode)->truncate_mutex);
  41                 ext4_discard_reservation(inode);
  42                 mutex_unlock(&EXT4_I(inode)->truncate_mutex);
  43         }
  44         if (is_dx(inode) && filp->private_data)
  45                 ext4_htree_free_dir_info(filp->private_data);
  46
  47         return 0;
  48 }
  49
  50 static ssize_t
  51 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  52                 unsigned long nr_segs, loff_t pos)
  53 {
  54         struct file *file = iocb->ki_filp;
  55         struct inode *inode = file->f_path.dentry->d_inode;
  56         ssize_t ret;
  57         int err;
  58
  59         ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
  60
  61         /*
  62          * Skip flushing if there was an error, or if nothing was written.
  63          */
  64         if (ret <= 0)
  65                 return ret;
  66
  67         /*
  68          * If the inode is IS_SYNC, or is O_SYNC and we are doing data
  69          * journalling then we need to make sure that we force the transaction
  70          * to disk to keep all metadata uptodate synchronously.
  71          */
  72         if (file->f_flags & O_SYNC) {
  73                 /*
  74                  * If we are non-data-journaled, then the dirty data has
  75                  * already been flushed to backing store by generic_osync_inode,
  76                  * and the inode has been flushed too if there have been any
  77                  * modifications other than mere timestamp updates.
  78                  *
  79                  * Open question --- do we care about flushing timestamps too
  80                  * if the inode is IS_SYNC?
  81                  */
  82                 if (!ext4_should_journal_data(inode))
  83                         return ret;
  84
  85                 goto force_commit;
  86         }
  87
  88         /*
  89          * So we know that there has been no forced data flush.  If the inode
  90          * is marked IS_SYNC, we need to force one ourselves.
  91          */
  92         if (!IS_SYNC(inode))
  93                 return ret;
  94
  95         /*
  96          * Open question #2 --- should we force data to disk here too?  If we
  97          * don't, the only impact is that data=writeback filesystems won't
  98          * flush data to disk automatically on IS_SYNC, only metadata (but
  99          * historically, that is what ext2 has done.)
 100          */
 101
 102 force_commit:
 103         err = ext4_force_commit(inode->i_sb);
 104         if (err)
 105                 return err;
 106         return ret;
 107 }
 108
 109 const struct file_operations ext4_file_operations = {
 110         .llseek         = generic_file_llseek,
 111         .read           = do_sync_read,
 112         .write          = do_sync_write,
 113         .aio_read       = generic_file_aio_read,
 114         .aio_write      = ext4_file_write,
 115         .ioctl          = ext4_ioctl,
 116 #ifdef CONFIG_COMPAT
 117         .compat_ioctl   = ext4_compat_ioctl,
 118 #endif
 119         .mmap           = generic_file_mmap,
 120         .open           = generic_file_open,
 121         .release        = ext4_release_file,
 122         .fsync          = ext4_sync_file,
 123         .sendfile       = generic_file_sendfile,
 124         .splice_read    = generic_file_splice_read,
 125         .splice_write   = generic_file_splice_write,
 126 };
 127
 128 struct inode_operations ext4_file_inode_operations = {
 129         .truncate       = ext4_truncate,
 130         .setattr        = ext4_setattr,
 131 #ifdef CONFIG_EXT4DEV_FS_XATTR
 132         .setxattr       = generic_setxattr,
 133         .getxattr       = generic_getxattr,
 134         .listxattr      = ext4_listxattr,
 135         .removexattr    = generic_removexattr,
 136 #endif
 137         .permission     = ext4_permission,
 138 };
 139