include/linux/mount.h

   1 /*
   2  *
   3  * Definitions for mount interface. This describes the in the kernel build
   4  * linkedlist with mounted filesystems.
   5  *
   6  * Author:  Marco van Wieringen <mvw@planets.elm.net>
   7  *
   8  */
   9 #ifndef _LINUX_MOUNT_H
  10 #define _LINUX_MOUNT_H
  11
  12 #include <linux/types.h>
  13 #include <linux/list.h>
  14 #include <linux/nodemask.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/seqlock.h>
  17 #include <linux/atomic.h>
  18
  19 struct super_block;
  20 struct vfsmount;
  21 struct dentry;
  22 struct mnt_namespace;
  23
  24 #define MNT_NOSUID      0x01
  25 #define MNT_NODEV       0x02
  26 #define MNT_NOEXEC      0x04
  27 #define MNT_NOATIME     0x08
  28 #define MNT_NODIRATIME  0x10
  29 #define MNT_RELATIME    0x20
  30 #define MNT_READONLY    0x40    /* does the user want this to be r/o? */
  31
  32 #define MNT_SHRINKABLE  0x100
  33 #define MNT_WRITE_HOLD  0x200
  34
  35 #define MNT_SHARED      0x1000  /* if the vfsmount is a shared mount */
  36 #define MNT_UNBINDABLE  0x2000  /* if the vfsmount is a unbindable mount */
  37 /*
  38  * MNT_SHARED_MASK is the set of flags that should be cleared when a
  39  * mount becomes shared.  Currently, this is only the flag that says a
  40  * mount cannot be bind mounted, since this is how we create a mount
  41  * that shares events with another mount.  If you add a new MNT_*
  42  * flag, consider how it interacts with shared mounts.
  43  */
  44 #define MNT_SHARED_MASK (MNT_UNBINDABLE)
  45 #define MNT_PROPAGATION_MASK    (MNT_SHARED | MNT_UNBINDABLE)
  46
  47
  48 #define MNT_INTERNAL    0x4000
  49
  50 struct vfsmount {
  51         struct dentry *mnt_root;        /* root of the mounted tree */
  52         struct super_block *mnt_sb;     /* pointer to superblock */
  53         int mnt_flags;
  54         /* 4 bytes hole on 64bits arches without fsnotify */
  55 #ifdef CONFIG_FSNOTIFY
  56         __u32 mnt_fsnotify_mask;
  57         struct hlist_head mnt_fsnotify_marks;
  58 #endif
  59         const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  60         struct list_head mnt_list;
  61         struct mnt_namespace *mnt_ns;   /* containing namespace */
  62         int mnt_id;                     /* mount identifier */
  63         int mnt_group_id;               /* peer group identifier */
  64         int mnt_expiry_mark;            /* true if marked for expiry */
  65         int mnt_pinned;
  66         int mnt_ghosts;
  67 };
  68
  69 struct file; /* forward dec */
  70
  71 extern int mnt_want_write(struct vfsmount *mnt);
  72 extern int mnt_want_write_file(struct file *file);
  73 extern int mnt_clone_write(struct vfsmount *mnt);
  74 extern void mnt_drop_write(struct vfsmount *mnt);
  75 extern void mnt_drop_write_file(struct file *file);
  76 extern void mntput(struct vfsmount *mnt);
  77 extern struct vfsmount *mntget(struct vfsmount *mnt);
  78 extern void mnt_pin(struct vfsmount *mnt);
  79 extern void mnt_unpin(struct vfsmount *mnt);
  80 extern int __mnt_is_readonly(struct vfsmount *mnt);
  81
  82 struct file_system_type;
  83 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
  84                                       int flags, const char *name,
  85                                       void *data);
  86
  87 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
  88 extern void mark_mounts_for_expiry(struct list_head *mounts);
  89
  90 extern dev_t name_to_dev_t(char *name);
  91
  92 #endif /* _LINUX_MOUNT_H */