fs/bad_inode.c

   1 /*
   2  *  linux/fs/bad_inode.c
   3  *
   4  *  Copyright (C) 1997, Stephen Tweedie
   5  *
   6  *  Provide stub functions for unreadable inodes
   7  *
   8  *  Fabian Frederick : August 2003 - All file operations assigned to EIO
   9  */
  10
  11 #include <linux/fs.h>
  12 #include <linux/export.h>
  13 #include <linux/stat.h>
  14 #include <linux/time.h>
  15 #include <linux/namei.h>
  16 #include <linux/poll.h>
  17
  18 static int bad_file_open(struct inode *inode, struct file *filp)
  19 {
  20         return -EIO;
  21 }
  22
  23 static const struct file_operations bad_file_ops =
  24 {
  25         .open           = bad_file_open,
  26 };
  27
  28 static int bad_inode_create (struct inode *dir, struct dentry *dentry,
  29                 umode_t mode, bool excl)
  30 {
  31         return -EIO;
  32 }
  33
  34 static struct dentry *bad_inode_lookup(struct inode *dir,
  35                         struct dentry *dentry, unsigned int flags)
  36 {
  37         return ERR_PTR(-EIO);
  38 }
  39
  40 static int bad_inode_link (struct dentry *old_dentry, struct inode *dir,
  41                 struct dentry *dentry)
  42 {
  43         return -EIO;
  44 }
  45
  46 static int bad_inode_unlink(struct inode *dir, struct dentry *dentry)
  47 {
  48         return -EIO;
  49 }
  50
  51 static int bad_inode_symlink (struct inode *dir, struct dentry *dentry,
  52                 const char *symname)
  53 {
  54         return -EIO;
  55 }
  56
  57 static int bad_inode_mkdir(struct inode *dir, struct dentry *dentry,
  58                         umode_t mode)
  59 {
  60         return -EIO;
  61 }
  62
  63 static int bad_inode_rmdir (struct inode *dir, struct dentry *dentry)
  64 {
  65         return -EIO;
  66 }
  67
  68 static int bad_inode_mknod (struct inode *dir, struct dentry *dentry,
  69                         umode_t mode, dev_t rdev)
  70 {
  71         return -EIO;
  72 }
  73
  74 static int bad_inode_rename2(struct inode *old_dir, struct dentry *old_dentry,
  75                              struct inode *new_dir, struct dentry *new_dentry,
  76                              unsigned int flags)
  77 {
  78         return -EIO;
  79 }
  80
  81 static int bad_inode_readlink(struct dentry *dentry, char __user *buffer,
  82                 int buflen)
  83 {
  84         return -EIO;
  85 }
  86
  87 static int bad_inode_permission(struct inode *inode, int mask)
  88 {
  89         return -EIO;
  90 }
  91
  92 static int bad_inode_getattr(struct vfsmount *mnt, struct dentry *dentry,
  93                         struct kstat *stat)
  94 {
  95         return -EIO;
  96 }
  97
  98 static int bad_inode_setattr(struct dentry *direntry, struct iattr *attrs)
  99 {
 100         return -EIO;
 101 }
 102
 103 static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
 104                         size_t buffer_size)
 105 {
 106         return -EIO;
 107 }
 108
 109 static const struct inode_operations bad_inode_ops =
 110 {
 111         .create         = bad_inode_create,
 112         .lookup         = bad_inode_lookup,
 113         .link           = bad_inode_link,
 114         .unlink         = bad_inode_unlink,
 115         .symlink        = bad_inode_symlink,
 116         .mkdir          = bad_inode_mkdir,
 117         .rmdir          = bad_inode_rmdir,
 118         .mknod          = bad_inode_mknod,
 119         .rename         = bad_inode_rename2,
 120         .readlink       = bad_inode_readlink,
 121         /* follow_link must be no-op, otherwise unmounting this inode
 122            won't work */
 123         /* put_link returns void */
 124         /* truncate returns void */
 125         .permission     = bad_inode_permission,
 126         .getattr        = bad_inode_getattr,
 127         .setattr        = bad_inode_setattr,
 128         .listxattr      = bad_inode_listxattr,
 129 };
 130
 131
 132 /*
 133  * When a filesystem is unable to read an inode due to an I/O error in
 134  * its read_inode() function, it can call make_bad_inode() to return a
 135  * set of stubs which will return EIO errors as required.
 136  *
 137  * We only need to do limited initialisation: all other fields are
 138  * preinitialised to zero automatically.
 139  */
 140
 141 /**
 142  *      make_bad_inode - mark an inode bad due to an I/O error
 143  *      @inode: Inode to mark bad
 144  *
 145  *      When an inode cannot be read due to a media or remote network
 146  *      failure this function makes the inode "bad" and causes I/O operations
 147  *      on it to fail from this point on.
 148  */
 149
 150 void make_bad_inode(struct inode *inode)
 151 {
 152         remove_inode_hash(inode);
 153
 154         inode->i_mode = S_IFREG;
 155         inode->i_atime = inode->i_mtime = inode->i_ctime =
 156                 current_time(inode);
 157         inode->i_op = &bad_inode_ops;
 158         inode->i_opflags &= ~IOP_XATTR;
 159         inode->i_fop = &bad_file_ops;
 160 }
 161 EXPORT_SYMBOL(make_bad_inode);
 162
 163 /*
 164  * This tests whether an inode has been flagged as bad. The test uses
 165  * &bad_inode_ops to cover the case of invalidated inodes as well as
 166  * those created by make_bad_inode() above.
 167  */
 168
 169 /**
 170  *      is_bad_inode - is an inode errored
 171  *      @inode: inode to test
 172  *
 173  *      Returns true if the inode in question has been marked as bad.
 174  */
 175
 176 bool is_bad_inode(struct inode *inode)
 177 {
 178         return (inode->i_op == &bad_inode_ops);
 179 }
 180
 181 EXPORT_SYMBOL(is_bad_inode);
 182
 183 /**
 184  * iget_failed - Mark an under-construction inode as dead and release it
 185  * @inode: The inode to discard
 186  *
 187  * Mark an under-construction inode as dead and release it.
 188  */
 189 void iget_failed(struct inode *inode)
 190 {
 191         make_bad_inode(inode);
 192         unlock_new_inode(inode);
 193         iput(inode);
 194 }
 195 EXPORT_SYMBOL(iget_failed);