include/linux/loop.h

   1 #ifndef _LINUX_LOOP_H
   2 #define _LINUX_LOOP_H
   3
   4 /*
   5  * include/linux/loop.h
   6  *
   7  * Written by Theodore Ts'o, 3/29/93.
   8  *
   9  * Copyright 1993 by Theodore Ts'o.  Redistribution of this file is
  10  * permitted under the GNU General Public License.
  11  */
  12
  13 #define LO_NAME_SIZE    64
  14 #define LO_KEY_SIZE     32
  15
  16 #ifdef __KERNEL__
  17 #include <linux/bio.h>
  18 #include <linux/blkdev.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/mutex.h>
  21
  22 /* Possible states of device */
  23 enum {
  24         Lo_unbound,
  25         Lo_bound,
  26         Lo_rundown,
  27 };
  28
  29 struct loop_func_table;
  30
  31 struct loop_device {
  32         int             lo_number;
  33         int             lo_refcnt;
  34         loff_t          lo_offset;
  35         loff_t          lo_sizelimit;
  36         int             lo_flags;
  37         int             (*transfer)(struct loop_device *, int cmd,
  38                                     struct page *raw_page, unsigned raw_off,
  39                                     struct page *loop_page, unsigned loop_off,
  40                                     int size, sector_t real_block);
  41         char            lo_file_name[LO_NAME_SIZE];
  42         char            lo_crypt_name[LO_NAME_SIZE];
  43         char            lo_encrypt_key[LO_KEY_SIZE];
  44         int             lo_encrypt_key_size;
  45         struct loop_func_table *lo_encryption;
  46         __u32           lo_init[2];
  47         uid_t           lo_key_owner;   /* Who set the key */
  48         int             (*ioctl)(struct loop_device *, int cmd,
  49                                  unsigned long arg);
  50
  51         struct file *   lo_backing_file;
  52         struct block_device *lo_device;
  53         struct block_device *fs_bdev;
  54         unsigned        lo_blocksize;
  55         void            *key_data;
  56         unsigned int    lo_switch;
  57
  58         gfp_t           old_gfp_mask;
  59
  60         spinlock_t              lo_lock;
  61         struct bio              *lo_bio;
  62         struct bio              *lo_biotail;
  63         unsigned int            lo_bio_cnt;
  64         int                     lo_state;
  65         struct mutex            lo_ctl_mutex;
  66         struct task_struct      *lo_thread;
  67         wait_queue_head_t       lo_event;
  68         wait_queue_head_t       lo_bio_wait;
  69         struct timer_list       lo_bio_timer;
  70
  71         struct request_queue    *lo_queue;
  72         struct gendisk          *lo_disk;
  73         struct list_head        lo_list;
  74
  75         unsigned int            blkbits;
  76 };
  77
  78 #endif /* __KERNEL__ */
  79
  80 /*
  81  * Loop flags
  82  */
  83 enum {
  84         LO_FLAGS_READ_ONLY      = 1,
  85         LO_FLAGS_USE_AOPS       = 2,
  86         LO_FLAGS_AUTOCLEAR      = 4,
  87         LO_FLAGS_FASTFS         = 8,
  88 };
  89
  90 #include <asm/posix_types.h>    /* for __kernel_old_dev_t */
  91 #include <linux/types.h>        /* for __u64 */
  92
  93 /* Backwards compatibility version */
  94 struct loop_info {
  95         int                lo_number;           /* ioctl r/o */
  96         __kernel_old_dev_t lo_device;           /* ioctl r/o */
  97         unsigned long      lo_inode;            /* ioctl r/o */
  98         __kernel_old_dev_t lo_rdevice;          /* ioctl r/o */
  99         int                lo_offset;
 100         int                lo_encrypt_type;
 101         int                lo_encrypt_key_size;         /* ioctl w/o */
 102         int                lo_flags;                    /* ioctl r/o */
 103         char               lo_name[LO_NAME_SIZE];
 104         unsigned char      lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
 105         unsigned long      lo_init[2];
 106         char               reserved[4];
 107 };
 108
 109 struct loop_info64 {
 110         __u64              lo_device;                   /* ioctl r/o */
 111         __u64              lo_inode;                    /* ioctl r/o */
 112         __u64              lo_rdevice;                  /* ioctl r/o */
 113         __u64              lo_offset;
 114         __u64              lo_sizelimit;/* bytes, 0 == max available */
 115         __u32              lo_number;                   /* ioctl r/o */
 116         __u32              lo_encrypt_type;
 117         __u32              lo_encrypt_key_size;         /* ioctl w/o */
 118         __u32              lo_flags;                    /* ioctl r/o */
 119         __u8               lo_file_name[LO_NAME_SIZE];
 120         __u8               lo_crypt_name[LO_NAME_SIZE];
 121         __u8               lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
 122         __u64              lo_init[2];
 123 };
 124
 125 /*
 126  * Loop filter types
 127  */
 128
 129 #define LO_CRYPT_NONE           0
 130 #define LO_CRYPT_XOR            1
 131 #define LO_CRYPT_DES            2
 132 #define LO_CRYPT_FISH2          3    /* Twofish encryption */
 133 #define LO_CRYPT_BLOW           4
 134 #define LO_CRYPT_CAST128        5
 135 #define LO_CRYPT_IDEA           6
 136 #define LO_CRYPT_DUMMY          9
 137 #define LO_CRYPT_SKIPJACK       10
 138 #define LO_CRYPT_CRYPTOAPI      18
 139 #define MAX_LO_CRYPT            20
 140
 141 #ifdef __KERNEL__
 142 /* Support for loadable transfer modules */
 143 struct loop_func_table {
 144         int number;     /* filter type */
 145         int (*transfer)(struct loop_device *lo, int cmd,
 146                         struct page *raw_page, unsigned raw_off,
 147                         struct page *loop_page, unsigned loop_off,
 148                         int size, sector_t real_block);
 149         int (*init)(struct loop_device *, const struct loop_info64 *);
 150         /* release is called from loop_unregister_transfer or clr_fd */
 151         int (*release)(struct loop_device *);
 152         int (*ioctl)(struct loop_device *, int cmd, unsigned long arg);
 153         struct module *owner;
 154 };
 155
 156 int loop_register_transfer(struct loop_func_table *funcs);
 157 int loop_unregister_transfer(int number);
 158
 159 #endif
 160 /*
 161  * IOCTL commands --- we will commandeer 0x4C ('L')
 162  */
 163
 164 #define LOOP_SET_FD             0x4C00
 165 #define LOOP_CLR_FD             0x4C01
 166 #define LOOP_SET_STATUS         0x4C02
 167 #define LOOP_GET_STATUS         0x4C03
 168 #define LOOP_SET_STATUS64       0x4C04
 169 #define LOOP_GET_STATUS64       0x4C05
 170 #define LOOP_CHANGE_FD          0x4C06
 171 #define LOOP_SET_FASTFS         0x4C07
 172
 173 enum {
 174         LOOP_EXTENT_RW_MAGIC =  0x19283744,
 175         LOOP_SWITCH_RW_MAGIC =  0xfeedbeec,
 176 };
 177
 178 #endif