include/linux/umsdos_fs_i.h

   1 #ifndef UMSDOS_FS_I_H
   2 #define UMSDOS_FS_I_H
   3
   4 #ifndef _LINUX_TYPES_H
   5 #include <linux/types.h>
   6 #endif
   7
   8 #include <linux/msdos_fs_i.h>
   9 #include <linux/pipe_fs_i.h>
  10
  11 /* #Specification: strategy / in memory inode
  12  * Here is the information specific to the inode of the UMSDOS file
  13  * system. This information is added to the end of the standard struct
  14  * inode. Each file system has its own extension to struct inode,
  15  * so do the umsdos file system.
  16  *
  17  * The strategy is to have the umsdos_inode_info as a superset of
  18  * the msdos_inode_info, since most of the time the job is done
  19  * by the msdos fs code.
  20  *
  21  * So we duplicate the msdos_inode_info, and add our own info at the
  22  * end.
  23  *
  24  * For all file type (and directory) the inode has a reference to:
  25  * the directory which hold this entry: i_dir_owner
  26  * The EMD file of i_dir_owner: i_emd_owner
  27  * The offset in this EMD file of the entry: pos
  28  *
  29  * For directory, we also have a reference to the inode of its
  30  * own EMD file. Also, we have dir_locking_info to help synchronise
  31  * file creation and file lookup. This data is sharing space with
  32  * the pipe_inode_info not used by directory. See also msdos_fs_i.h
  33  * for more information about pipe_inode_info and msdos_inode_info.
  34  *
  35  * Special file and fifo do have an inode which correspond to an
  36  * empty MSDOS file.
  37  *
  38  * symlink are processed mostly like regular file. The content is the
  39  * link.
  40  *
  41  * fifos add there own extension to the inode. I have reserved some
  42  * space for fifos side by side with msdos_inode_info. This is just
  43  * to for the show, because msdos_inode_info already include the
  44  * pipe_inode_info.
  45  *
  46  * The UMSDOS specific extension is placed after the union.
  47  */
  48
  49 struct dir_locking_info {
  50         wait_queue_head_t p;
  51         short int looking;      /* How many process doing a lookup */
  52         short int creating;     /* Is there any creation going on here
  53                                  *  Only one at a time, although one
  54                                  *  may recursively lock, so it is a counter
  55                                  */
  56         long pid;               /* pid of the process owning the creation */
  57         /* lock */
  58 };
  59
  60 struct umsdos_inode_info {
  61         union {
  62                 struct msdos_inode_info msdos_info;
  63                 struct pipe_inode_info pipe_info;
  64                 struct dir_locking_info dir_info;
  65         } u;
  66         int i_patched;                  /* Inode has been patched */
  67         int i_is_hlink;                 /* Resolved hardlink inode? */
  68         unsigned long i_emd_owner;      /* Is this the EMD file inode? */
  69         off_t pos;                      /* Entry offset in the emd_owner file */
  70         /* The rest is used only if this inode describes a directory */
  71         struct dentry *i_emd_dentry;    /* EMD dentry for this directory */
  72         unsigned long i_emd_dir;        /* Inode of the EMD file */
  73 };
  74
  75 #endif