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 "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                         !EXT4_I(inode)->i_reserved_data_blocks)
  44         {
  45                 down_write(&EXT4_I(inode)->i_data_sem);
  46                 ext4_discard_preallocations(inode);
  47                 up_write(&EXT4_I(inode)->i_data_sem);
  48         }
  49         if (is_dx(inode) && filp->private_data)
  50                 ext4_htree_free_dir_info(filp->private_data);
  51
  52         return 0;
  53 }
  54
  55 static ssize_t
  56 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  57                 unsigned long nr_segs, loff_t pos)
  58 {
  59         struct file *file = iocb->ki_filp;
  60         struct inode *inode = file->f_path.dentry->d_inode;
  61         ssize_t ret;
  62         int err;
  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         ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
  83         /*
  84          * Skip flushing if there was an error, or if nothing was written.
  85          */
  86         if (ret <= 0)
  87                 return ret;
  88
  89         /*
  90          * If the inode is IS_SYNC, or is O_SYNC and we are doing data
  91          * journalling then we need to make sure that we force the transaction
  92          * to disk to keep all metadata uptodate synchronously.
  93          */
  94         if (file->f_flags & O_SYNC) {
  95                 /*
  96                  * If we are non-data-journaled, then the dirty data has
  97                  * already been flushed to backing store by generic_osync_inode,
  98                  * and the inode has been flushed too if there have been any
  99                  * modifications other than mere timestamp updates.
 100                  *
 101                  * Open question --- do we care about flushing timestamps too
 102                  * if the inode is IS_SYNC?
 103                  */
 104                 if (!ext4_should_journal_data(inode))
 105                         return ret;
 106
 107                 goto force_commit;
 108         }
 109
 110         /*
 111          * So we know that there has been no forced data flush.  If the inode
 112          * is marked IS_SYNC, we need to force one ourselves.
 113          */
 114         if (!IS_SYNC(inode))
 115                 return ret;
 116
 117         /*
 118          * Open question #2 --- should we force data to disk here too?  If we
 119          * don't, the only impact is that data=writeback filesystems won't
 120          * flush data to disk automatically on IS_SYNC, only metadata (but
 121          * historically, that is what ext2 has done.)
 122          */
 123
 124 force_commit:
 125         err = ext4_force_commit(inode->i_sb);
 126         if (err)
 127                 return err;
 128         return ret;
 129 }
 130
 131 static struct vm_operations_struct ext4_file_vm_ops = {
 132         .fault          = filemap_fault,
 133         .page_mkwrite   = ext4_page_mkwrite,
 134 };
 135
 136 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 137 {
 138         struct address_space *mapping = file->f_mapping;
 139
 140         if (!mapping->a_ops->readpage)
 141                 return -ENOEXEC;
 142         file_accessed(file);
 143         vma->vm_ops = &ext4_file_vm_ops;
 144         vma->vm_flags |= VM_CAN_NONLINEAR;
 145         return 0;
 146 }
 147
 148 const struct file_operations ext4_file_operations = {
 149         .llseek         = generic_file_llseek,
 150         .read           = do_sync_read,
 151         .write          = do_sync_write,
 152         .aio_read       = generic_file_aio_read,
 153         .aio_write      = ext4_file_write,
 154         .unlocked_ioctl = ext4_ioctl,
 155 #ifdef CONFIG_COMPAT
 156         .compat_ioctl   = ext4_compat_ioctl,
 157 #endif
 158         .mmap           = ext4_file_mmap,
 159         .open           = generic_file_open,
 160         .release        = ext4_release_file,
 161         .fsync          = ext4_sync_file,
 162         .splice_read    = generic_file_splice_read,
 163         .splice_write   = generic_file_splice_write,
 164 };
 165
 166 const struct inode_operations ext4_file_inode_operations = {
 167         .truncate       = ext4_truncate,
 168         .setattr        = ext4_setattr,
 169         .getattr        = ext4_getattr,
 170 #ifdef CONFIG_EXT4_FS_XATTR
 171         .setxattr       = generic_setxattr,
 172         .getxattr       = generic_getxattr,
 173         .listxattr      = ext4_listxattr,
 174         .removexattr    = generic_removexattr,
 175 #endif
 176         .permission     = ext4_permission,
 177         .fallocate      = ext4_fallocate,
 178         .fiemap         = ext4_fiemap,
 179 };
 180