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  */
  37 static 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
  58 static ssize_t
  59 ext4_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                     (pos == sbi->s_bitmap_maxbytes && length > 0)))
  75                         return -EFBIG;
  76
  77                 if (pos + length > sbi->s_bitmap_maxbytes) {
  78                         nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
  79                                               sbi->s_bitmap_maxbytes - pos);
  80                 }
  81         }
  82
  83         return generic_file_aio_write(iocb, iov, nr_segs, pos);
  84 }
  85
  86 static const struct vm_operations_struct ext4_file_vm_ops = {
  87         .fault          = filemap_fault,
  88         .page_mkwrite   = ext4_page_mkwrite,
  89 };
  90
  91 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
  92 {
  93         struct address_space *mapping = file->f_mapping;
  94
  95         if (!mapping->a_ops->readpage)
  96                 return -ENOEXEC;
  97         file_accessed(file);
  98         vma->vm_ops = &ext4_file_vm_ops;
  99         vma->vm_flags |= VM_CAN_NONLINEAR;
 100         return 0;
 101 }
 102
 103 static int ext4_file_open(struct inode * inode, struct file * filp)
 104 {
 105         struct super_block *sb = inode->i_sb;
 106         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 107         struct vfsmount *mnt = filp->f_path.mnt;
 108         struct path path;
 109         char buf[64], *cp;
 110
 111         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 112                      !(sb->s_flags & MS_RDONLY))) {
 113                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 114                 /*
 115                  * Sample where the filesystem has been mounted and
 116                  * store it in the superblock for sysadmin convenience
 117                  * when trying to sort through large numbers of block
 118                  * devices or filesystem images.
 119                  */
 120                 memset(buf, 0, sizeof(buf));
 121                 path.mnt = mnt;
 122                 path.dentry = mnt->mnt_root;
 123                 cp = d_path(&path, buf, sizeof(buf));
 124                 if (!IS_ERR(cp)) {
 125                         memcpy(sbi->s_es->s_last_mounted, cp,
 126                                sizeof(sbi->s_es->s_last_mounted));
 127                         ext4_mark_super_dirty(sb);
 128                 }
 129         }
 130         return dquot_file_open(inode, filp);
 131 }
 132
 133 /*
 134  * ext4_llseek() copied from generic_file_llseek() to handle both
 135  * block-mapped and extent-mapped maxbytes values. This should
 136  * otherwise be identical with generic_file_llseek().
 137  */
 138 loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
 139 {
 140         struct inode *inode = file->f_mapping->host;
 141         loff_t maxbytes;
 142
 143         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 144                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
 145         else
 146                 maxbytes = inode->i_sb->s_maxbytes;
 147         mutex_lock(&inode->i_mutex);
 148         switch (origin) {
 149         case SEEK_END:
 150                 offset += inode->i_size;
 151                 break;
 152         case SEEK_CUR:
 153                 if (offset == 0) {
 154                         mutex_unlock(&inode->i_mutex);
 155                         return file->f_pos;
 156                 }
 157                 offset += file->f_pos;
 158                 break;
 159         }
 160
 161         if (offset < 0 || offset > maxbytes) {
 162                 mutex_unlock(&inode->i_mutex);
 163                 return -EINVAL;
 164         }
 165
 166         if (offset != file->f_pos) {
 167                 file->f_pos = offset;
 168                 file->f_version = 0;
 169         }
 170         mutex_unlock(&inode->i_mutex);
 171
 172         return offset;
 173 }
 174
 175 const struct file_operations ext4_file_operations = {
 176         .llseek         = ext4_llseek,
 177         .read           = do_sync_read,
 178         .write          = do_sync_write,
 179         .aio_read       = generic_file_aio_read,
 180         .aio_write      = ext4_file_write,
 181         .unlocked_ioctl = ext4_ioctl,
 182 #ifdef CONFIG_COMPAT
 183         .compat_ioctl   = ext4_compat_ioctl,
 184 #endif
 185         .mmap           = ext4_file_mmap,
 186         .open           = ext4_file_open,
 187         .release        = ext4_release_file,
 188         .fsync          = ext4_sync_file,
 189         .splice_read    = generic_file_splice_read,
 190         .splice_write   = generic_file_splice_write,
 191 };
 192
 193 const struct inode_operations ext4_file_inode_operations = {
 194         .truncate       = ext4_truncate,
 195         .setattr        = ext4_setattr,
 196         .getattr        = ext4_getattr,
 197 #ifdef CONFIG_EXT4_FS_XATTR
 198         .setxattr       = generic_setxattr,
 199         .getxattr       = generic_getxattr,
 200         .listxattr      = ext4_listxattr,
 201         .removexattr    = generic_removexattr,
 202 #endif
 203         .check_acl      = ext4_check_acl,
 204         .fallocate      = ext4_fallocate,
 205         .fiemap         = ext4_fiemap,
 206 };
 207