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/module.h>
  13 #include <linux/stat.h>
  14 #include <linux/time.h>
  15 #include <linux/smp_lock.h>
  16
  17 /*
  18  * The follow_link operation is special: it must behave as a no-op
  19  * so that a bad root inode can at least be unmounted. To do this
  20  * we must dput() the base and return the dentry with a dget().
  21  */
  22 static int bad_follow_link(struct dentry *dent, struct nameidata *nd)
  23 {
  24         return vfs_follow_link(nd, ERR_PTR(-EIO));
  25 }
  26
  27 static int return_EIO(void)
  28 {
  29         return -EIO;
  30 }
  31
  32 #define EIO_ERROR ((void *) (return_EIO))
  33
  34 static struct file_operations bad_file_ops =
  35 {
  36         .llseek         = EIO_ERROR,
  37         .aio_read       = EIO_ERROR,
  38         .read           = EIO_ERROR,
  39         .write          = EIO_ERROR,
  40         .aio_write      = EIO_ERROR,
  41         .readdir        = EIO_ERROR,
  42         .poll           = EIO_ERROR,
  43         .ioctl          = EIO_ERROR,
  44         .mmap           = EIO_ERROR,
  45         .open           = EIO_ERROR,
  46         .flush          = EIO_ERROR,
  47         .release        = EIO_ERROR,
  48         .fsync          = EIO_ERROR,
  49         .aio_fsync      = EIO_ERROR,
  50         .fasync         = EIO_ERROR,
  51         .lock           = EIO_ERROR,
  52         .readv          = EIO_ERROR,
  53         .writev         = EIO_ERROR,
  54         .sendfile       = EIO_ERROR,
  55         .sendpage       = EIO_ERROR,
  56         .get_unmapped_area = EIO_ERROR,
  57 };
  58
  59 struct inode_operations bad_inode_ops =
  60 {
  61         .create         = EIO_ERROR,
  62         .lookup         = EIO_ERROR,
  63         .link           = EIO_ERROR,
  64         .unlink         = EIO_ERROR,
  65         .symlink        = EIO_ERROR,
  66         .mkdir          = EIO_ERROR,
  67         .rmdir          = EIO_ERROR,
  68         .mknod          = EIO_ERROR,
  69         .rename         = EIO_ERROR,
  70         .readlink       = EIO_ERROR,
  71         .follow_link    = bad_follow_link,
  72         .truncate       = EIO_ERROR,
  73         .permission     = EIO_ERROR,
  74         .getattr        = EIO_ERROR,
  75         .setattr        = EIO_ERROR,
  76         .setxattr       = EIO_ERROR,
  77         .getxattr       = EIO_ERROR,
  78         .listxattr      = EIO_ERROR,
  79         .removexattr    = EIO_ERROR,
  80 };
  81
  82
  83 /*
  84  * When a filesystem is unable to read an inode due to an I/O error in
  85  * its read_inode() function, it can call make_bad_inode() to return a
  86  * set of stubs which will return EIO errors as required.
  87  *
  88  * We only need to do limited initialisation: all other fields are
  89  * preinitialised to zero automatically.
  90  */
  91
  92 /**
  93  *      make_bad_inode - mark an inode bad due to an I/O error
  94  *      @inode: Inode to mark bad
  95  *
  96  *      When an inode cannot be read due to a media or remote network
  97  *      failure this function makes the inode "bad" and causes I/O operations
  98  *      on it to fail from this point on.
  99  */
 100
 101 void make_bad_inode(struct inode * inode)
 102 {
 103         remove_inode_hash(inode);
 104
 105         inode->i_mode = S_IFREG;
 106         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 107         inode->i_op = &bad_inode_ops;
 108         inode->i_fop = &bad_file_ops;
 109 }
 110 EXPORT_SYMBOL(make_bad_inode);
 111
 112 /*
 113  * This tests whether an inode has been flagged as bad. The test uses
 114  * &bad_inode_ops to cover the case of invalidated inodes as well as
 115  * those created by make_bad_inode() above.
 116  */
 117
 118 /**
 119  *      is_bad_inode - is an inode errored
 120  *      @inode: inode to test
 121  *
 122  *      Returns true if the inode in question has been marked as bad.
 123  */
 124
 125 int is_bad_inode(struct inode * inode)
 126 {
 127         return (inode->i_op == &bad_inode_ops);
 128 }
 129
 130 EXPORT_SYMBOL(is_bad_inode);