#ifndef __SHMEM_FS_H
  #define __SHMEM_FS_H
  
  #include <linux/swap.h>
  #include <linux/mempolicy.h>

  #include <linux/percpu_counter.h>

  
  /* inode in-kernel data */
  
  #define SHMEM_NR_DIRECT 16
  
  struct shmem_inode_info {
  	spinlock_t		lock;
  	unsigned long		flags;
  	unsigned long		alloced;	/* data pages alloced to file */
  	unsigned long		swapped;	/* subtotal assigned to swap */
  	unsigned long		next_index;	/* highest alloced index + 1 */
  	struct shared_policy	policy;		/* NUMA memory alloc policy */
  	struct page		*i_indirect;	/* top indirect blocks page */
  	swp_entry_t		i_direct[SHMEM_NR_DIRECT]; /* first blocks */
  	struct list_head	swaplist;	/* chain of maybes on swap */
  	struct inode		vfs_inode;
  };
  
  struct shmem_sb_info {
  	unsigned long max_blocks;   /* How many blocks are allowed */

  	struct percpu_counter used_blocks;  /* How many are allocated */

  	unsigned long max_inodes;   /* How many inodes are allowed */
  	unsigned long free_inodes;  /* How many are left for allocation */

  	spinlock_t stat_lock;	    /* Serialize shmem_sb_info changes */
  	uid_t uid;		    /* Mount uid for root directory */
  	gid_t gid;		    /* Mount gid for root directory */
  	mode_t mode;		    /* Mount mode for root directory */

  	struct mempolicy *mpol;     /* default memory policy for mappings */

  };
  
  static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
  {
  	return container_of(inode, struct shmem_inode_info, vfs_inode);
  }

  extern int init_tmpfs(void);
  extern int shmem_fill_super(struct super_block *sb, void *data, int silent);

  #endif