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      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 (at) planets.elm.net>
      7  *
      8  * Version: $Id: mount.h,v 2.0 1996/11/17 16:48:14 mvw Exp mvw $
      9  *
     10  */
     11 #ifndef _LINUX_MOUNT_H
     12 #define _LINUX_MOUNT_H
     13 #ifdef __KERNEL__
     14 
     15 #include <linux/types.h>
     16 #include <linux/list.h>
     17 #include <linux/spinlock.h>
     18 #include <asm/atomic.h>
     19 
     20 struct super_block;
     21 struct vfsmount;
     22 struct dentry;
     23 struct namespace;
     24 
     25 #define MNT_NOSUID	0x01
     26 #define MNT_NODEV	0x02
     27 #define MNT_NOEXEC	0x04
     28 #define MNT_NOATIME	0x08
     29 #define MNT_NODIRATIME	0x10
     30 
     31 #define MNT_SHRINKABLE	0x100
     32 
     33 #define MNT_SHARED	0x1000	/* if the vfsmount is a shared mount */
     34 #define MNT_UNBINDABLE	0x2000	/* if the vfsmount is a unbindable mount */
     35 #define MNT_PNODE_MASK	0x3000	/* propogation flag mask */
     36 
     37 struct vfsmount {
     38 	struct list_head mnt_hash;
     39 	struct vfsmount *mnt_parent;	/* fs we are mounted on */
     40 	struct dentry *mnt_mountpoint;	/* dentry of mountpoint */
     41 	struct dentry *mnt_root;	/* root of the mounted tree */
     42 	struct super_block *mnt_sb;	/* pointer to superblock */
     43 	struct list_head mnt_mounts;	/* list of children, anchored here */
     44 	struct list_head mnt_child;	/* and going through their mnt_child */
     45 	atomic_t mnt_count;
     46 	int mnt_flags;
     47 	int mnt_expiry_mark;		/* true if marked for expiry */
     48 	char *mnt_devname;		/* Name of device e.g. /dev/dsk/hda1 */
     49 	struct list_head mnt_list;
     50 	struct list_head mnt_expire;	/* link in fs-specific expiry list */
     51 	struct list_head mnt_share;	/* circular list of shared mounts */
     52 	struct list_head mnt_slave_list;/* list of slave mounts */
     53 	struct list_head mnt_slave;	/* slave list entry */
     54 	struct vfsmount *mnt_master;	/* slave is on master->mnt_slave_list */
     55 	struct namespace *mnt_namespace; /* containing namespace */
     56 	int mnt_pinned;
     57 };
     58 
     59 static inline struct vfsmount *mntget(struct vfsmount *mnt)
     60 {
     61 	if (mnt)
     62 		atomic_inc(&mnt->mnt_count);
     63 	return mnt;
     64 }
     65 
     66 extern void mntput_no_expire(struct vfsmount *mnt);
     67 extern void mnt_pin(struct vfsmount *mnt);
     68 extern void mnt_unpin(struct vfsmount *mnt);
     69 
     70 static inline void mntput(struct vfsmount *mnt)
     71 {
     72 	if (mnt) {
     73 		mnt->mnt_expiry_mark = 0;
     74 		mntput_no_expire(mnt);
     75 	}
     76 }
     77 
     78 extern void free_vfsmnt(struct vfsmount *mnt);
     79 extern struct vfsmount *alloc_vfsmnt(const char *name);
     80 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
     81 				      const char *name, void *data);
     82 
     83 struct file_system_type;
     84 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
     85 				      int flags, const char *name,
     86 				      void *data);
     87 
     88 struct nameidata;
     89 
     90 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
     91 			int mnt_flags, struct list_head *fslist);
     92 
     93 extern void mark_mounts_for_expiry(struct list_head *mounts);
     94 extern void shrink_submounts(struct vfsmount *mountpoint, struct list_head *mounts);
     95 
     96 extern spinlock_t vfsmount_lock;
     97 extern dev_t name_to_dev_t(char *name);
     98 
     99 #endif
    100 #endif /* _LINUX_MOUNT_H */
    101