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 mnt_pcp {
  51         int mnt_count;
  52         int mnt_writers;
  53 };
  54
  55 struct vfsmount {
  56         struct list_head mnt_hash;
  57         struct vfsmount *mnt_parent;    /* fs we are mounted on */
  58         struct dentry *mnt_mountpoint;  /* dentry of mountpoint */
  59         struct dentry *mnt_root;        /* root of the mounted tree */
  60         struct super_block *mnt_sb;     /* pointer to superblock */
  61 #ifdef CONFIG_SMP
  62         struct mnt_pcp __percpu *mnt_pcp;
  63         atomic_t mnt_longterm;          /* how many of the refs are longterm */
  64 #else
  65         int mnt_count;
  66         int mnt_writers;
  67 #endif
  68         struct list_head mnt_mounts;    /* list of children, anchored here */
  69         struct list_head mnt_child;     /* and going through their mnt_child */
  70         int mnt_flags;
  71         /* 4 bytes hole on 64bits arches without fsnotify */
  72 #ifdef CONFIG_FSNOTIFY
  73         __u32 mnt_fsnotify_mask;
  74         struct hlist_head mnt_fsnotify_marks;
  75 #endif
  76         const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  77         struct list_head mnt_list;
  78         struct list_head mnt_expire;    /* link in fs-specific expiry list */
  79         struct list_head mnt_share;     /* circular list of shared mounts */
  80         struct list_head mnt_slave_list;/* list of slave mounts */
  81         struct list_head mnt_slave;     /* slave list entry */
  82         struct vfsmount *mnt_master;    /* slave is on master->mnt_slave_list */
  83         struct mnt_namespace *mnt_ns;   /* containing namespace */
  84         int mnt_id;                     /* mount identifier */
  85         int mnt_group_id;               /* peer group identifier */
  86         int mnt_expiry_mark;            /* true if marked for expiry */
  87         int mnt_pinned;
  88         int mnt_ghosts;
  89 };
  90
  91 struct file; /* forward dec */
  92
  93 extern int mnt_want_write(struct vfsmount *mnt);
  94 extern int mnt_want_write_file(struct file *file);
  95 extern int mnt_clone_write(struct vfsmount *mnt);
  96 extern void mnt_drop_write(struct vfsmount *mnt);
  97 extern void mntput(struct vfsmount *mnt);
  98 extern struct vfsmount *mntget(struct vfsmount *mnt);
  99 extern void mnt_pin(struct vfsmount *mnt);
 100 extern void mnt_unpin(struct vfsmount *mnt);
 101 extern int __mnt_is_readonly(struct vfsmount *mnt);
 102
 103 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
 104                                       const char *name, void *data);
 105
 106 struct file_system_type;
 107 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
 108                                       int flags, const char *name,
 109                                       void *data);
 110
 111 extern void mnt_set_expiry(struct vfsmount *mnt, struct list_head *expiry_list);
 112 extern void mark_mounts_for_expiry(struct list_head *mounts);
 113
 114 extern dev_t name_to_dev_t(char *name);
 115
 116 #endif /* _LINUX_MOUNT_H */