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 "ext4.h"
  27 #include "ext4_jbd2.h"
  28 #include "xattr.h"
  29 #include "acl.h"
  30
  31 /*
  32  * Called when an inode is released. Note that this is different
  33  * from ext4_file_open: open gets called at every open, but release
  34  * gets called only when /all/ the files are closed.
  35  */
  36 static int ext4_release_file(struct inode *inode, struct file *filp)
  37 {
  38         if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
  39                 ext4_alloc_da_blocks(inode);
  40                 EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
  41         }
  42         /* if we are the last writer on the inode, drop the block reservation */
  43         if ((filp->f_mode & FMODE_WRITE) &&
  44                         (atomic_read(&inode->i_writecount) == 1) &&
  45                         !EXT4_I(inode)->i_reserved_data_blocks)
  46         {
  47                 down_write(&EXT4_I(inode)->i_data_sem);
  48                 ext4_discard_preallocations(inode);
  49                 up_write(&EXT4_I(inode)->i_data_sem);
  50         }
  51         if (is_dx(inode) && filp->private_data)
  52                 ext4_htree_free_dir_info(filp->private_data);
  53
  54         return 0;
  55 }
  56
  57 static ssize_t
  58 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  59                 unsigned long nr_segs, loff_t pos)
  60 {
  61         struct file *file = iocb->ki_filp;
  62         struct inode *inode = file->f_path.dentry->d_inode;
  63         ssize_t ret;
  64         int err;
  65
  66         /*
  67          * If we have encountered a bitmap-format file, the size limit
  68          * is smaller than s_maxbytes, which is for extent-mapped files.
  69          */
  70
  71         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
  72                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  73                 size_t length = iov_length(iov, nr_segs);
  74
  75                 if (pos > sbi->s_bitmap_maxbytes)
  76                         return -EFBIG;
  77
  78                 if (pos + length > sbi->s_bitmap_maxbytes) {
  79                         nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
  80                                               sbi->s_bitmap_maxbytes - pos);
  81                 }
  82         }
  83
  84         ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
  85         /*
  86          * Skip flushing if there was an error, or if nothing was written.
  87          */
  88         if (ret <= 0)
  89                 return ret;
  90
  91         /*
  92          * If the inode is IS_SYNC, or is O_SYNC and we are doing data
  93          * journalling then we need to make sure that we force the transaction
  94          * to disk to keep all metadata uptodate synchronously.
  95          */
  96         if (file->f_flags & O_SYNC) {
  97                 /*
  98                  * If we are non-data-journaled, then the dirty data has
  99                  * already been flushed to backing store by generic_osync_inode,
 100                  * and the inode has been flushed too if there have been any
 101                  * modifications other than mere timestamp updates.
 102                  *
 103                  * Open question --- do we care about flushing timestamps too
 104                  * if the inode is IS_SYNC?
 105                  */
 106                 if (!ext4_should_journal_data(inode))
 107                         return ret;
 108
 109                 goto force_commit;
 110         }
 111
 112         /*
 113          * So we know that there has been no forced data flush.  If the inode
 114          * is marked IS_SYNC, we need to force one ourselves.
 115          */
 116         if (!IS_SYNC(inode))
 117                 return ret;
 118
 119         /*
 120          * Open question #2 --- should we force data to disk here too?  If we
 121          * don't, the only impact is that data=writeback filesystems won't
 122          * flush data to disk automatically on IS_SYNC, only metadata (but
 123          * historically, that is what ext2 has done.)
 124          */
 125
 126 force_commit:
 127         err = ext4_force_commit(inode->i_sb);
 128         if (err)
 129                 return err;
 130         return ret;
 131 }
 132
 133 static struct vm_operations_struct ext4_file_vm_ops = {
 134         .fault          = filemap_fault,
 135         .page_mkwrite   = ext4_page_mkwrite,
 136 };
 137
 138 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 139 {
 140         struct address_space *mapping = file->f_mapping;
 141
 142         if (!mapping->a_ops->readpage)
 143                 return -ENOEXEC;
 144         file_accessed(file);
 145         vma->vm_ops = &ext4_file_vm_ops;
 146         vma->vm_flags |= VM_CAN_NONLINEAR;
 147         return 0;
 148 }
 149
 150 static int ext4_file_open(struct inode * inode, struct file * filp)
 151 {
 152         struct super_block *sb = inode->i_sb;
 153         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 154         struct vfsmount *mnt = filp->f_path.mnt;
 155         struct path path;
 156         char buf[64], *cp;
 157
 158         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 159                      !(sb->s_flags & MS_RDONLY))) {
 160                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 161                 /*
 162                  * Sample where the filesystem has been mounted and
 163                  * store it in the superblock for sysadmin convenience
 164                  * when trying to sort through large numbers of block
 165                  * devices or filesystem images.
 166                  */
 167                 memset(buf, 0, sizeof(buf));
 168                 path.mnt = mnt->mnt_parent;
 169                 path.dentry = mnt->mnt_mountpoint;
 170                 path_get(&path);
 171                 cp = d_path(&path, buf, sizeof(buf));
 172                 path_put(&path);
 173                 if (!IS_ERR(cp)) {
 174                         memcpy(sbi->s_es->s_last_mounted, cp,
 175                                sizeof(sbi->s_es->s_last_mounted));
 176                         sb->s_dirt = 1;
 177                 }
 178         }
 179         return generic_file_open(inode, filp);
 180 }
 181
 182 const struct file_operations ext4_file_operations = {
 183         .llseek         = generic_file_llseek,
 184         .read           = do_sync_read,
 185         .write          = do_sync_write,
 186         .aio_read       = generic_file_aio_read,
 187         .aio_write      = ext4_file_write,
 188         .unlocked_ioctl = ext4_ioctl,
 189 #ifdef CONFIG_COMPAT
 190         .compat_ioctl   = ext4_compat_ioctl,
 191 #endif
 192         .mmap           = ext4_file_mmap,
 193         .open           = ext4_file_open,
 194         .release        = ext4_release_file,
 195         .fsync          = ext4_sync_file,
 196         .splice_read    = generic_file_splice_read,
 197         .splice_write   = generic_file_splice_write,
 198 };
 199
 200 const struct inode_operations ext4_file_inode_operations = {
 201         .truncate       = ext4_truncate,
 202         .setattr        = ext4_setattr,
 203         .getattr        = ext4_getattr,
 204 #ifdef CONFIG_EXT4_FS_XATTR
 205         .setxattr       = generic_setxattr,
 206         .getxattr       = generic_getxattr,
 207         .listxattr      = ext4_listxattr,
 208         .removexattr    = generic_removexattr,
 209 #endif
 210         .check_acl      = ext4_check_acl,
 211         .fallocate      = ext4_fallocate,
 212         .fiemap         = ext4_fiemap,
 213 };
 214