src/lxc/bdev.h

   1 #ifndef __LXC_BDEV_H
   2 #define __LXC_BDEV_H
   3 /* blockdev operations for:
   4  * dir, raw, btrfs, overlayfs, aufs, lvm, loop, zfs, btrfs
   5  * someday: qemu-nbd, qcow2, qed
   6  */
   7
   8 #include "config.h"
   9 #include "lxccontainer.h"
  10
  11 struct bdev;
  12
  13 /*
  14  * specifications for how to create a new backing store
  15  */
  16 struct bdev_specs {
  17         union {
  18                 struct {
  19                         char *zfsroot;
  20                 } zfs;
  21                 struct {
  22                         char *vg;
  23                         char *lv;
  24                         char *fstype;
  25                         unsigned long fssize;  // fs size in bytes
  26                 } lvm;
  27         } u;
  28 };
  29
  30 struct bdev_ops {
  31         /* detect whether path is of this bdev type */
  32         int (*detect)(const char *path);
  33         // mount requires src and dest to be set.
  34         int (*mount)(struct bdev *bdev);
  35         int (*umount)(struct bdev *bdev);
  36         int (*destroy)(struct bdev *bdev);
  37         int (*create)(struct bdev *bdev, const char *dest, const char *n,
  38                         struct bdev_specs *specs);
  39         /* given original mount, rename the paths for cloned container */
  40         int (*clone_paths)(struct bdev *orig, struct bdev *new, const char *oldname,
  41                         const char *cname, const char *oldpath, const char *lxcpath,
  42                         int snap, unsigned long newsize);
  43 };
  44
  45 /*
  46  * When lxc-start (conf.c) is mounting a rootfs, then src will be the
  47  * 'lxc.rootfs' value, dest will be mount dir (i.e. $libdir/lxc)  When clone
  48  * or create is doing so, then dest will be $lxcpath/$lxcname/rootfs, since
  49  * we may need to rsync from one to the other.
  50  * data is so far unused.
  51  */
  52 struct bdev {
  53         struct bdev_ops *ops;
  54         char *type;
  55         char *src;
  56         char *dest;
  57         char *data;
  58 };
  59
  60 char *overlayfs_getlower(char *p);
  61
  62 /*
  63  * Instantiate a bdev object.  The src is used to determine which blockdev
  64  * type this should be.  The dst and data are optional, and will be used
  65  * in case of mount/umount.
  66  *
  67  * Optionally, src can be 'dir:/var/lib/lxc/c1' or 'lvm:/dev/lxc/c1'.  For
  68  * other backing stores, this will allow additional options.  In particular,
  69  * "overlayfs:/var/lib/lxc/canonical/rootfs:/var/lib/lxc/c1/delta" will mean
  70  * use /var/lib/lxc/canonical/rootfs as lower dir, and /var/lib/lxc/c1/delta
  71  * as the upper, writeable layer.
  72  */
  73 struct bdev *bdev_init(const char *src, const char *dst, const char *data);
  74
  75 struct bdev *bdev_copy(const char *src, const char *oldname, const char *cname,
  76                         const char *oldpath, const char *lxcpath, const char *bdevtype,
  77                         int snap, const char *bdevdata, unsigned long newsize);
  78 struct bdev *bdev_create(const char *dest, const char *type,
  79                         const char *cname, struct bdev_specs *specs);
  80 void bdev_put(struct bdev *bdev);
  81
  82 /* define constants if the kernel/glibc headers don't define them */
  83 #ifndef MS_DIRSYNC
  84 #define MS_DIRSYNC  128
  85 #endif
  86
  87 #ifndef MS_REC
  88 #define MS_REC 16384
  89 #endif
  90
  91 #ifndef MNT_DETACH
  92 #define MNT_DETACH 2
  93 #endif
  94
  95 #ifndef MS_SLAVE
  96 #define MS_SLAVE (1<<19)
  97 #endif
  98
  99 #ifndef MS_RELATIME
 100 #define MS_RELATIME (1 << 21)
 101 #endif
 102
 103 #ifndef MS_STRICTATIME
 104 #define MS_STRICTATIME (1 << 24)
 105 #endif
 106
 107 #endif