#ifndef _LINUX_FS_H
  #define _LINUX_FS_H
  
  /*
   * This file has definitions for some important file table
   * structures etc.
   */

  #include <linux/limits.h>
  #include <linux/ioctl.h>

  #include <linux/blk_types.h>

  #include <linux/types.h>

  
  /*
   * It's silly to have NR_OPEN bigger than NR_FILE, but you can change
   * the file limit at runtime and only root can increase the per-process
   * nr_file rlimit, so it's safe to set up a ridiculously high absolute
   * upper limit on files-per-process.
   *
   * Some programs (notably those using select()) may have to be 
   * recompiled to take full advantage of the new limits..  
   */
  
  /* Fixed constants first: */
  #undef NR_OPEN

  #define INR_OPEN_CUR 1024	/* Initial setting for nfile rlimits */
  #define INR_OPEN_MAX 4096	/* Hard limit for nfile rlimits */

  
  #define BLOCK_SIZE_BITS 10
  #define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)

  #define SEEK_SET	0	/* seek relative to beginning of file */
  #define SEEK_CUR	1	/* seek relative to current file position */
  #define SEEK_END	2	/* seek relative to end of file */

  #define SEEK_DATA	3	/* seek to the next data */
  #define SEEK_HOLE	4	/* seek to the next hole */
  #define SEEK_MAX	SEEK_HOLE

  struct fstrim_range {

  	__u64 start;
  	__u64 len;
  	__u64 minlen;

  };

  /* And dynamically-tunable limits and defaults: */
  struct files_stat_struct {

  	unsigned long nr_files;		/* read only */
  	unsigned long nr_free_files;	/* read only */
  	unsigned long max_files;		/* tunable */

  };

  
  struct inodes_stat_t {
  	int nr_inodes;
  	int nr_unused;

  	int dummy[5];		/* padding for sysctl ABI compatibility */

  };

  
  #define NR_FILE  8192	/* this can well be larger on a larger system */

  #define MAY_EXEC		0x00000001
  #define MAY_WRITE		0x00000002
  #define MAY_READ		0x00000004
  #define MAY_APPEND		0x00000008
  #define MAY_ACCESS		0x00000010
  #define MAY_OPEN		0x00000020
  #define MAY_CHDIR		0x00000040
  /* called from RCU mode, don't block */
  #define MAY_NOT_BLOCK		0x00000080

  /*
   * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
   * to O_WRONLY and O_RDWR via the strange trick in __dentry_open()
   */

  /* file is open for reading */

  #define FMODE_READ		((__force fmode_t)0x1)

  /* file is open for writing */

  #define FMODE_WRITE		((__force fmode_t)0x2)

  /* file is seekable */

  #define FMODE_LSEEK		((__force fmode_t)0x4)

  /* file can be accessed using pread */

  #define FMODE_PREAD		((__force fmode_t)0x8)

  /* file can be accessed using pwrite */

  #define FMODE_PWRITE		((__force fmode_t)0x10)

  /* File is opened for execution with sys_execve / sys_uselib */

  #define FMODE_EXEC		((__force fmode_t)0x20)

  /* File is opened with O_NDELAY (only set for block devices) */

  #define FMODE_NDELAY		((__force fmode_t)0x40)

  /* File is opened with O_EXCL (only set for block devices) */

  #define FMODE_EXCL		((__force fmode_t)0x80)

  /* File is opened using open(.., 3, ..) and is writeable only for ioctls
     (specialy hack for floppy.c) */

  #define FMODE_WRITE_IOCTL	((__force fmode_t)0x100)

  /*
   * Don't update ctime and mtime.
   *
   * Currently a special hack for the XFS open_by_handle ioctl, but we'll
   * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
   */

  #define FMODE_NOCMTIME		((__force fmode_t)0x800)

  /* Expect random access pattern */

  #define FMODE_RANDOM		((__force fmode_t)0x1000)

  /* File is huge (eg. /dev/kmem): treat loff_t as unsigned */
  #define FMODE_UNSIGNED_OFFSET	((__force fmode_t)0x2000)

  /* File is opened with O_PATH; almost nothing can be done with it */
  #define FMODE_PATH		((__force fmode_t)0x4000)

  /* File was opened by fanotify and shouldn't generate fanotify events */

  #define FMODE_NONOTIFY		((__force fmode_t)0x1000000)

  /*
   * The below are the various read and write types that we support. Some of
   * them include behavioral modifiers that send information down to the
   * block layer and IO scheduler. Terminology:
   *
   *	The block layer uses device plugging to defer IO a little bit, in
   *	the hope that we will see more IO very shortly. This increases
   *	coalescing of adjacent IO and thus reduces the number of IOs we
   *	have to send to the device. It also allows for better queuing,
   *	if the IO isn't mergeable. If the caller is going to be waiting
   *	for the IO, then he must ensure that the device is unplugged so
   *	that the IO is dispatched to the driver.
   *
   *	All IO is handled async in Linux. This is fine for background
   *	writes, but for reads or writes that someone waits for completion
   *	on, we want to notify the block layer and IO scheduler so that they
   *	know about it. That allows them to make better scheduling
   *	decisions. So when the below references 'sync' and 'async', it
   *	is referencing this priority hint.
   *
   * With that in mind, the available types are:
   *
   * READ			A normal read operation. Device will be plugged.
   * READ_SYNC		A synchronous read. Device is not plugged, caller can
   *			immediately wait on this read without caring about
   *			unplugging.
   * READA		Used for read-ahead operations. Lower priority, and the

   *			block layer could (in theory) choose to ignore this

   *			request if it runs into resource problems.
   * WRITE		A normal async write. Device will be plugged.

   * WRITE_SYNC		Synchronous write. Identical to WRITE, but passes down

   *			the hint that someone will be waiting on this IO

   *			shortly. The write equivalent of READ_SYNC.
   * WRITE_ODIRECT	Special case write for O_DIRECT only.

   * WRITE_FLUSH		Like WRITE_SYNC but with preceding cache flush.
   * WRITE_FUA		Like WRITE_SYNC but data is guaranteed to be on
   *			non-volatile media on completion.
   * WRITE_FLUSH_FUA	Combination of WRITE_FLUSH and FUA. The IO is preceded
   *			by a cache flush and data is guaranteed to be on
   *			non-volatile media on completion.

   *
   */

  #define RW_MASK			REQ_WRITE
  #define RWA_MASK		REQ_RAHEAD

  
  #define READ			0

  #define WRITE			RW_MASK
  #define READA			RWA_MASK

  #define READ_SYNC		(READ | REQ_SYNC)

  #define WRITE_SYNC		(WRITE | REQ_SYNC | REQ_NOIDLE)
  #define WRITE_ODIRECT		(WRITE | REQ_SYNC)

  #define WRITE_FLUSH		(WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
  #define WRITE_FUA		(WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
  #define WRITE_FLUSH_FUA		(WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)

  
  #define SEL_IN		1
  #define SEL_OUT		2
  #define SEL_EX		4
  
  /* public flags for file_system_type */
  #define FS_REQUIRES_DEV 1 
  #define FS_BINARY_MOUNTDATA 2

  #define FS_HAS_SUBTYPE 4

  #define FS_REVAL_DOT	16384	/* Check the paths ".", ".." for staleness */

  #define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move()
  					 * during rename() internally.
  					 */

  /*
   * These are the fs-independent mount-flags: up to 32 flags are supported
   */
  #define MS_RDONLY	 1	/* Mount read-only */
  #define MS_NOSUID	 2	/* Ignore suid and sgid bits */
  #define MS_NODEV	 4	/* Disallow access to device special files */
  #define MS_NOEXEC	 8	/* Disallow program execution */
  #define MS_SYNCHRONOUS	16	/* Writes are synced at once */
  #define MS_REMOUNT	32	/* Alter flags of a mounted FS */
  #define MS_MANDLOCK	64	/* Allow mandatory locks on an FS */
  #define MS_DIRSYNC	128	/* Directory modifications are synchronous */
  #define MS_NOATIME	1024	/* Do not update access times. */
  #define MS_NODIRATIME	2048	/* Do not update directory access times */
  #define MS_BIND		4096
  #define MS_MOVE		8192
  #define MS_REC		16384

  #define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
  				   MS_VERBOSE is deprecated. */
  #define MS_SILENT	32768

  #define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */

  #define MS_UNBINDABLE	(1<<17)	/* change to unbindable */

  #define MS_PRIVATE	(1<<18)	/* change to private */

  #define MS_SLAVE	(1<<19)	/* change to slave */

  #define MS_SHARED	(1<<20)	/* change to shared */

  #define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */

  #define MS_KERNMOUNT	(1<<22) /* this is a kern_mount call */

  #define MS_I_VERSION	(1<<23) /* Update inode I_version field */

  #define MS_STRICTATIME	(1<<24) /* Always perform atime updates */

  #define MS_NOSEC	(1<<28)

  #define MS_BORN		(1<<29)

  #define MS_ACTIVE	(1<<30)
  #define MS_NOUSER	(1<<31)
  
  /*
   * Superblock flags that can be altered by MS_REMOUNT
   */

  #define MS_RMT_MASK	(MS_RDONLY|MS_SYNCHRONOUS|MS_MANDLOCK|MS_I_VERSION)

  
  /*
   * Old magic mount flag and mask
   */
  #define MS_MGC_VAL 0xC0ED0000
  #define MS_MGC_MSK 0xffff0000
  
  /* Inode flags - they have nothing to superblock flags now */
  
  #define S_SYNC		1	/* Writes are synced at once */
  #define S_NOATIME	2	/* Do not update access times */
  #define S_APPEND	4	/* Append-only file */
  #define S_IMMUTABLE	8	/* Immutable file */
  #define S_DEAD		16	/* removed, but still open directory */
  #define S_NOQUOTA	32	/* Inode is not counted to quota */
  #define S_DIRSYNC	64	/* Directory modifications are synchronous */
  #define S_NOCMTIME	128	/* Do not update file c/mtime */
  #define S_SWAPFILE	256	/* Do not truncate: swapon got its bmaps */
  #define S_PRIVATE	512	/* Inode is fs-internal */

  #define S_IMA		1024	/* Inode has an associated IMA struct */

  #define S_AUTOMOUNT	2048	/* Automount/referral quasi-directory */

  #define S_NOSEC		4096	/* no suid or xattr security attributes */

  
  /*
   * Note that nosuid etc flags are inode-specific: setting some file-system
   * flags just means all the inodes inherit those flags by default. It might be
   * possible to override it selectively if you really wanted to with some
   * ioctl() that is not currently implemented.
   *
   * Exception: MS_RDONLY is always applied to the entire file system.
   *
   * Unfortunately, it is possible to change a filesystems flags with it mounted
   * with files in use.  This means that all of the inodes will not have their
   * i_flags updated.  Hence, i_flags no longer inherit the superblock mount
   * flags, so these have to be checked separately. -- rmk@arm.uk.linux.org
   */
  #define __IS_FLG(inode,flg) ((inode)->i_sb->s_flags & (flg))
  
  #define IS_RDONLY(inode) ((inode)->i_sb->s_flags & MS_RDONLY)
  #define IS_SYNC(inode)		(__IS_FLG(inode, MS_SYNCHRONOUS) || \
  					((inode)->i_flags & S_SYNC))
  #define IS_DIRSYNC(inode)	(__IS_FLG(inode, MS_SYNCHRONOUS|MS_DIRSYNC) || \
  					((inode)->i_flags & (S_SYNC|S_DIRSYNC)))
  #define IS_MANDLOCK(inode)	__IS_FLG(inode, MS_MANDLOCK)

  #define IS_NOATIME(inode)   __IS_FLG(inode, MS_RDONLY|MS_NOATIME)

  #define IS_I_VERSION(inode)   __IS_FLG(inode, MS_I_VERSION)

  
  #define IS_NOQUOTA(inode)	((inode)->i_flags & S_NOQUOTA)
  #define IS_APPEND(inode)	((inode)->i_flags & S_APPEND)
  #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)

  #define IS_POSIXACL(inode)	__IS_FLG(inode, MS_POSIXACL)
  
  #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
  #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)
  #define IS_SWAPFILE(inode)	((inode)->i_flags & S_SWAPFILE)
  #define IS_PRIVATE(inode)	((inode)->i_flags & S_PRIVATE)

  #define IS_IMA(inode)		((inode)->i_flags & S_IMA)

  #define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)

  #define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)

  
  /* the read-only stuff doesn't really belong here, but any other place is
     probably as bad and I don't want to create yet another include file. */
  
  #define BLKROSET   _IO(0x12,93)	/* set device read-only (0 = read-write) */
  #define BLKROGET   _IO(0x12,94)	/* get read-only status (0 = read_write) */
  #define BLKRRPART  _IO(0x12,95)	/* re-read partition table */
  #define BLKGETSIZE _IO(0x12,96)	/* return device size /512 (long *arg) */
  #define BLKFLSBUF  _IO(0x12,97)	/* flush buffer cache */
  #define BLKRASET   _IO(0x12,98)	/* set read ahead for block device */
  #define BLKRAGET   _IO(0x12,99)	/* get current read ahead setting */
  #define BLKFRASET  _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */
  #define BLKFRAGET  _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */
  #define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */
  #define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */
  #define BLKSSZGET  _IO(0x12,104)/* get block device sector size */
  #if 0
  #define BLKPG      _IO(0x12,105)/* See blkpg.h */
  
  /* Some people are morons.  Do not use sizeof! */
  
  #define BLKELVGET  _IOR(0x12,106,size_t)/* elevator get */
  #define BLKELVSET  _IOW(0x12,107,size_t)/* elevator set */
  /* This was here just to show that the number is taken -
     probably all these _IO(0x12,*) ioctls should be moved to blkpg.h. */
  #endif
  /* A jump here: 108-111 have been used for various private purposes. */
  #define BLKBSZGET  _IOR(0x12,112,size_t)
  #define BLKBSZSET  _IOW(0x12,113,size_t)
  #define BLKGETSIZE64 _IOR(0x12,114,size_t)	/* return device size in bytes (u64 *arg) */

  #define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
  #define BLKTRACESTART _IO(0x12,116)
  #define BLKTRACESTOP _IO(0x12,117)
  #define BLKTRACETEARDOWN _IO(0x12,118)

  #define BLKDISCARD _IO(0x12,119)

  #define BLKIOMIN _IO(0x12,120)
  #define BLKIOOPT _IO(0x12,121)
  #define BLKALIGNOFF _IO(0x12,122)
  #define BLKPBSZGET _IO(0x12,123)

  #define BLKDISCARDZEROES _IO(0x12,124)

  #define BLKSECDISCARD _IO(0x12,125)

  
  #define BMAP_IOCTL 1		/* obsolete - kept for compatibility */
  #define FIBMAP	   _IO(0x00,1)	/* bmap access */
  #define FIGETBSZ   _IO(0x00,2)	/* get the block size used for bmap */

  #define FIFREEZE	_IOWR('X', 119, int)	/* Freeze */
  #define FITHAW		_IOWR('X', 120, int)	/* Thaw */

  #define FITRIM		_IOWR('X', 121, struct fstrim_range)	/* Trim */

  #define	FS_IOC_GETFLAGS			_IOR('f', 1, long)
  #define	FS_IOC_SETFLAGS			_IOW('f', 2, long)
  #define	FS_IOC_GETVERSION		_IOR('v', 1, long)
  #define	FS_IOC_SETVERSION		_IOW('v', 2, long)

  #define FS_IOC_FIEMAP			_IOWR('f', 11, struct fiemap)

  #define FS_IOC32_GETFLAGS		_IOR('f', 1, int)
  #define FS_IOC32_SETFLAGS		_IOW('f', 2, int)
  #define FS_IOC32_GETVERSION		_IOR('v', 1, int)
  #define FS_IOC32_SETVERSION		_IOW('v', 2, int)
  
  /*
   * Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
   */
  #define	FS_SECRM_FL			0x00000001 /* Secure deletion */
  #define	FS_UNRM_FL			0x00000002 /* Undelete */
  #define	FS_COMPR_FL			0x00000004 /* Compress file */
  #define FS_SYNC_FL			0x00000008 /* Synchronous updates */
  #define FS_IMMUTABLE_FL			0x00000010 /* Immutable file */
  #define FS_APPEND_FL			0x00000020 /* writes to file may only append */
  #define FS_NODUMP_FL			0x00000040 /* do not dump file */
  #define FS_NOATIME_FL			0x00000080 /* do not update atime */
  /* Reserved for compression usage... */
  #define FS_DIRTY_FL			0x00000100
  #define FS_COMPRBLK_FL			0x00000200 /* One or more compressed clusters */
  #define FS_NOCOMP_FL			0x00000400 /* Don't compress */
  #define FS_ECOMPR_FL			0x00000800 /* Compression error */
  /* End compression flags --- maybe not all used */
  #define FS_BTREE_FL			0x00001000 /* btree format dir */
  #define FS_INDEX_FL			0x00001000 /* hash-indexed directory */
  #define FS_IMAGIC_FL			0x00002000 /* AFS directory */
  #define FS_JOURNAL_DATA_FL		0x00004000 /* Reserved for ext3 */
  #define FS_NOTAIL_FL			0x00008000 /* file tail should not be merged */
  #define FS_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
  #define FS_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/

  #define FS_EXTENT_FL			0x00080000 /* Extents */
  #define FS_DIRECTIO_FL			0x00100000 /* Use direct i/o */

  #define FS_NOCOW_FL			0x00800000 /* Do not cow file */

  #define FS_RESERVED_FL			0x80000000 /* reserved for ext2 lib */
  
  #define FS_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
  #define FS_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */

  #define SYNC_FILE_RANGE_WAIT_BEFORE	1
  #define SYNC_FILE_RANGE_WRITE		2
  #define SYNC_FILE_RANGE_WAIT_AFTER	4

  #ifdef __KERNEL__
  
  #include <linux/linkage.h>
  #include <linux/wait.h>

  #include <linux/kdev_t.h>
  #include <linux/dcache.h>

  #include <linux/path.h>

  #include <linux/stat.h>
  #include <linux/cache.h>

  #include <linux/list.h>
  #include <linux/radix-tree.h>
  #include <linux/prio_tree.h>
  #include <linux/init.h>

  #include <linux/pid.h>

  #include <linux/mutex.h>

  #include <linux/capability.h>

  #include <linux/semaphore.h>

  #include <linux/fiemap.h>

  #include <linux/rculist_bl.h>

  #include <linux/atomic.h>

  #include <linux/shrinker.h>

  #include <asm/byteorder.h>

  struct export_operations;

  struct hd_geometry;

  struct iovec;
  struct nameidata;

  struct kiocb;

  struct kobject;

  struct pipe_inode_info;
  struct poll_table_struct;
  struct kstatfs;
  struct vm_area_struct;
  struct vfsmount;

  struct cred;

  extern void __init inode_init(void);

  extern void __init inode_init_early(void);

  extern void __init files_init(unsigned long);

  extern struct files_stat_struct files_stat;

  extern unsigned long get_max_files(void);

  extern int sysctl_nr_open;
  extern struct inodes_stat_t inodes_stat;
  extern int leases_enable, lease_break_time;

  struct buffer_head;
  typedef int (get_block_t)(struct inode *inode, sector_t iblock,
  			struct buffer_head *bh_result, int create);

  typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,

  			ssize_t bytes, void *private, int ret,
  			bool is_async);

  
  /*
   * Attribute flags.  These should be or-ed together to figure out what
   * has been changed!
   */

  #define ATTR_MODE	(1 << 0)
  #define ATTR_UID	(1 << 1)
  #define ATTR_GID	(1 << 2)
  #define ATTR_SIZE	(1 << 3)
  #define ATTR_ATIME	(1 << 4)
  #define ATTR_MTIME	(1 << 5)
  #define ATTR_CTIME	(1 << 6)
  #define ATTR_ATIME_SET	(1 << 7)
  #define ATTR_MTIME_SET	(1 << 8)
  #define ATTR_FORCE	(1 << 9) /* Not a change, but a change it */
  #define ATTR_ATTR_FLAG	(1 << 10)
  #define ATTR_KILL_SUID	(1 << 11)
  #define ATTR_KILL_SGID	(1 << 12)
  #define ATTR_FILE	(1 << 13)
  #define ATTR_KILL_PRIV	(1 << 14)
  #define ATTR_OPEN	(1 << 15) /* Truncating from open(O_TRUNC) */
  #define ATTR_TIMES_SET	(1 << 16)

  
  /*
   * This is the Inode Attributes structure, used for notify_change().  It
   * uses the above definitions as flags, to know which values have changed.
   * Also, in this manner, a Filesystem can look at only the values it cares
   * about.  Basically, these are the attributes that the VFS layer can
   * request to change from the FS layer.
   *
   * Derek Atkins <warlord@MIT.EDU> 94-10-20
   */
  struct iattr {
  	unsigned int	ia_valid;
  	umode_t		ia_mode;
  	uid_t		ia_uid;
  	gid_t		ia_gid;
  	loff_t		ia_size;
  	struct timespec	ia_atime;
  	struct timespec	ia_mtime;
  	struct timespec	ia_ctime;

  
  	/*

  	 * Not an attribute, but an auxiliary info for filesystems wanting to

  	 * implement an ftruncate() like method.  NOTE: filesystem should
  	 * check for (ia_valid & ATTR_FILE), and not for (ia_file != NULL).
  	 */
  	struct file	*ia_file;

  };
  
  /*

   * Includes for diskquotas.
   */
  #include <linux/quota.h>

  /** 
   * enum positive_aop_returns - aop return codes with specific semantics
   *
   * @AOP_WRITEPAGE_ACTIVATE: Informs the caller that page writeback has
   * 			    completed, that the page is still locked, and
   * 			    should be considered active.  The VM uses this hint
   * 			    to return the page to the active list -- it won't
   * 			    be a candidate for writeback again in the near
   * 			    future.  Other callers must be careful to unlock
   * 			    the page if they get this return.  Returned by
   * 			    writepage(); 
   *
   * @AOP_TRUNCATED_PAGE: The AOP method that was handed a locked page has
   *  			unlocked it and the page might have been truncated.
   *  			The caller should back up to acquiring a new page and
   *  			trying again.  The aop will be taking reasonable
   *  			precautions not to livelock.  If the caller held a page
   *  			reference, it should drop it before retrying.  Returned

   *  			by readpage().

   *
   * address_space_operation functions return these large constants to indicate
   * special semantics to the caller.  These are much larger than the bytes in a
   * page to allow for functions that return the number of bytes operated on in a
   * given page.
   */
  
  enum positive_aop_returns {
  	AOP_WRITEPAGE_ACTIVATE	= 0x80000,
  	AOP_TRUNCATED_PAGE	= 0x80001,
  };

  #define AOP_FLAG_UNINTERRUPTIBLE	0x0001 /* will not do a short write */

  #define AOP_FLAG_CONT_EXPAND		0x0002 /* called from cont_expand */

  #define AOP_FLAG_NOFS			0x0004 /* used by filesystem to direct
  						* helper code (eg buffer layer)
  						* to clear GFP_FS from alloc */

  /*
   * oh the beauties of C type declarations.
   */
  struct page;
  struct address_space;
  struct writeback_control;

  struct iov_iter {
  	const struct iovec *iov;
  	unsigned long nr_segs;
  	size_t iov_offset;
  	size_t count;
  };
  
  size_t iov_iter_copy_from_user_atomic(struct page *page,
  		struct iov_iter *i, unsigned long offset, size_t bytes);
  size_t iov_iter_copy_from_user(struct page *page,
  		struct iov_iter *i, unsigned long offset, size_t bytes);
  void iov_iter_advance(struct iov_iter *i, size_t bytes);

  int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);

  size_t iov_iter_single_seg_count(struct iov_iter *i);
  
  static inline void iov_iter_init(struct iov_iter *i,
  			const struct iovec *iov, unsigned long nr_segs,
  			size_t count, size_t written)
  {
  	i->iov = iov;
  	i->nr_segs = nr_segs;
  	i->iov_offset = 0;
  	i->count = count + written;
  
  	iov_iter_advance(i, written);
  }
  
  static inline size_t iov_iter_count(struct iov_iter *i)
  {
  	return i->count;
  }

  /*
   * "descriptor" for what we're up to with a read.
   * This allows us to use the same read code yet
   * have multiple different users of the data that
   * we read from a file.
   *
   * The simplest case just copies the data to user
   * mode.
   */
  typedef struct {
  	size_t written;
  	size_t count;
  	union {
  		char __user *buf;
  		void *data;
  	} arg;
  	int error;
  } read_descriptor_t;
  
  typedef int (*read_actor_t)(read_descriptor_t *, struct page *,
  		unsigned long, unsigned long);

  struct address_space_operations {
  	int (*writepage)(struct page *page, struct writeback_control *wbc);
  	int (*readpage)(struct file *, struct page *);

  
  	/* Write back some dirty pages from this mapping. */
  	int (*writepages)(struct address_space *, struct writeback_control *);

  	/* Set a page dirty.  Return true if this dirtied it */

  	int (*set_page_dirty)(struct page *page);
  
  	int (*readpages)(struct file *filp, struct address_space *mapping,
  			struct list_head *pages, unsigned nr_pages);

  	int (*write_begin)(struct file *, struct address_space *mapping,
  				loff_t pos, unsigned len, unsigned flags,
  				struct page **pagep, void **fsdata);
  	int (*write_end)(struct file *, struct address_space *mapping,
  				loff_t pos, unsigned len, unsigned copied,
  				struct page *page, void *fsdata);

  	/* Unfortunately this kludge is needed for FIBMAP. Don't use it */
  	sector_t (*bmap)(struct address_space *, sector_t);

  	void (*invalidatepage) (struct page *, unsigned long);

  	int (*releasepage) (struct page *, gfp_t);

  	void (*freepage)(struct page *);

  	ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
  			loff_t offset, unsigned long nr_segs);

  	int (*get_xip_mem)(struct address_space *, pgoff_t, int,
  						void **, unsigned long *);

  	/* migrate the contents of a page to the specified target */

  	int (*migratepage) (struct address_space *,
  			struct page *, struct page *);

  	int (*launder_page) (struct page *);

  	int (*is_partially_uptodate) (struct page *, read_descriptor_t *,
  					unsigned long);

  	int (*error_remove_page)(struct address_space *, struct page *);

  };

  extern const struct address_space_operations empty_aops;

  /*
   * pagecache_write_begin/pagecache_write_end must be used by general code
   * to write into the pagecache.
   */
  int pagecache_write_begin(struct file *, struct address_space *mapping,
  				loff_t pos, unsigned len, unsigned flags,
  				struct page **pagep, void **fsdata);
  
  int pagecache_write_end(struct file *, struct address_space *mapping,
  				loff_t pos, unsigned len, unsigned copied,
  				struct page *page, void *fsdata);

  struct backing_dev_info;
  struct address_space {
  	struct inode		*host;		/* owner: inode, block_device */
  	struct radix_tree_root	page_tree;	/* radix tree of all pages */

  	spinlock_t		tree_lock;	/* and lock protecting it */

  	unsigned int		i_mmap_writable;/* count VM_SHARED mappings */
  	struct prio_tree_root	i_mmap;		/* tree of private and shared mappings */
  	struct list_head	i_mmap_nonlinear;/*list VM_NONLINEAR mappings */

  	struct mutex		i_mmap_mutex;	/* protect tree, count, list */

  	/* Protected by tree_lock together with the radix tree */

  	unsigned long		nrpages;	/* number of total pages */
  	pgoff_t			writeback_index;/* writeback starts here */

  	const struct address_space_operations *a_ops;	/* methods */

  	unsigned long		flags;		/* error bits/gfp mask */
  	struct backing_dev_info *backing_dev_info; /* device readahead, etc */
  	spinlock_t		private_lock;	/* for use by the address_space */
  	struct list_head	private_list;	/* ditto */
  	struct address_space	*assoc_mapping;	/* ditto */
  } __attribute__((aligned(sizeof(long))));
  	/*
  	 * On most architectures that alignment is already the case; but

  	 * must be enforced here for CRIS, to let the least significant bit

  	 * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
  	 */
  
  struct block_device {
  	dev_t			bd_dev;  /* not a kdev_t - it's a search key */

  	int			bd_openers;

  	struct inode *		bd_inode;	/* will die */

  	struct super_block *	bd_super;

  	struct mutex		bd_mutex;	/* open/close mutex */

  	struct list_head	bd_inodes;

  	void *			bd_claiming;

  	void *			bd_holder;
  	int			bd_holders;

  	bool			bd_write_holder;

  #ifdef CONFIG_SYSFS

  	struct list_head	bd_holder_disks;

  #endif

  	struct block_device *	bd_contains;
  	unsigned		bd_block_size;
  	struct hd_struct *	bd_part;
  	/* number of times partitions within this device have been opened. */
  	unsigned		bd_part_count;
  	int			bd_invalidated;
  	struct gendisk *	bd_disk;
  	struct list_head	bd_list;

  	/*
  	 * Private data.  You must have bd_claim'ed the block_device
  	 * to use this.  NOTE:  bd_claim allows an owner to claim
  	 * the same device multiple times, the owner must take special
  	 * care to not mess up bd_private for that case.
  	 */
  	unsigned long		bd_private;

  
  	/* The counter of freeze processes */
  	int			bd_fsfreeze_count;
  	/* Mutex for freeze */
  	struct mutex		bd_fsfreeze_mutex;

  };
  
  /*
   * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
   * radix trees
   */
  #define PAGECACHE_TAG_DIRTY	0
  #define PAGECACHE_TAG_WRITEBACK	1

  #define PAGECACHE_TAG_TOWRITE	2

  
  int mapping_tagged(struct address_space *mapping, int tag);
  
  /*
   * Might pages of this file be mapped into userspace?
   */
  static inline int mapping_mapped(struct address_space *mapping)
  {
  	return	!prio_tree_empty(&mapping->i_mmap) ||
  		!list_empty(&mapping->i_mmap_nonlinear);
  }
  
  /*
   * Might pages of this file have been modified in userspace?
   * Note that i_mmap_writable counts all VM_SHARED vmas: do_mmap_pgoff
   * marks vma as VM_SHARED if it is shared, and the file was opened for
   * writing i.e. vma may be mprotected writable even if now readonly.
   */
  static inline int mapping_writably_mapped(struct address_space *mapping)
  {
  	return mapping->i_mmap_writable != 0;
  }
  
  /*
   * Use sequence counter to get consistent i_size on 32-bit processors.
   */
  #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
  #include <linux/seqlock.h>
  #define __NEED_I_SIZE_ORDERED
  #define i_size_ordered_init(inode) seqcount_init(&inode->i_size_seqcount)
  #else
  #define i_size_ordered_init(inode) do { } while (0)
  #endif

  struct posix_acl;
  #define ACL_NOT_CACHED ((void *)(-1))

  #define IOP_FASTPERM	0x0001
  #define IOP_LOOKUP	0x0002
  #define IOP_NOFOLLOW	0x0004
  
  /*
   * Keep mostly read-only and often accessed (especially for
   * the RCU path lookup and 'stat' data) fields at the beginning
   * of the 'struct inode'
   */

  struct inode {

  	umode_t			i_mode;

  	unsigned short		i_opflags;

  	uid_t			i_uid;
  	gid_t			i_gid;

  	unsigned int		i_flags;
  
  #ifdef CONFIG_FS_POSIX_ACL
  	struct posix_acl	*i_acl;
  	struct posix_acl	*i_default_acl;
  #endif

  	const struct inode_operations	*i_op;
  	struct super_block	*i_sb;

  	struct address_space	*i_mapping;

  #ifdef CONFIG_SECURITY
  	void			*i_security;
  #endif

  	/* Stat data, not accessed from path walking */
  	unsigned long		i_ino;

  	/*
  	 * Filesystems may only read i_nlink directly.  They shall use the
  	 * following functions for modification:
  	 *
  	 *    (set|clear|inc|drop)_nlink
  	 *    inode_(inc|dec)_link_count
  	 */
  	union {
  		const unsigned int i_nlink;
  		unsigned int __i_nlink;
  	};

  	dev_t			i_rdev;

  	struct timespec		i_atime;
  	struct timespec		i_mtime;
  	struct timespec		i_ctime;

  	spinlock_t		i_lock;	/* i_blocks, i_bytes, maybe i_size */
  	unsigned short          i_bytes;

  	blkcnt_t		i_blocks;

  	loff_t			i_size;

  
  #ifdef __NEED_I_SIZE_ORDERED
  	seqcount_t		i_size_seqcount;
  #endif
  
  	/* Misc */
  	unsigned long		i_state;

  	struct mutex		i_mutex;

  	unsigned long		dirtied_when;	/* jiffies of first dirtying */

  	struct hlist_node	i_hash;

  	struct list_head	i_wb_list;	/* backing dev IO list */
  	struct list_head	i_lru;		/* inode LRU list */

  	struct list_head	i_sb_list;

  	union {
  		struct list_head	i_dentry;
  		struct rcu_head		i_rcu;
  	};

  	atomic_t		i_count;

  	unsigned int		i_blkbits;

  	u64			i_version;

  	atomic_t		i_dio_count;

  	atomic_t		i_writecount;

  	const struct file_operations	*i_fop;	/* former ->i_op->default_file_ops */

  	struct file_lock	*i_flock;

  	struct address_space	i_data;
  #ifdef CONFIG_QUOTA
  	struct dquot		*i_dquot[MAXQUOTAS];
  #endif

  	struct list_head	i_devices;

  	union {
  		struct pipe_inode_info	*i_pipe;

  		struct block_device	*i_bdev;

  		struct cdev		*i_cdev;

  	};

  
  	__u32			i_generation;

  #ifdef CONFIG_FSNOTIFY
  	__u32			i_fsnotify_mask; /* all events this inode cares about */

  	struct hlist_head	i_fsnotify_marks;

  #endif

  #ifdef CONFIG_IMA

  	atomic_t		i_readcount; /* struct files open RO */

  #endif

  	void			*i_private; /* fs or device private pointer */

  };

  static inline int inode_unhashed(struct inode *inode)
  {
  	return hlist_unhashed(&inode->i_hash);
  }

  /*

   * inode->i_mutex nesting subclasses for the lock validator:
   *
   * 0: the object of the current VFS operation
   * 1: parent
   * 2: child/target
   * 3: quota file
   *
   * The locking order between these classes is

   * parent -> child -> normal -> xattr -> quota

   */
  enum inode_i_mutex_lock_class
  {
  	I_MUTEX_NORMAL,
  	I_MUTEX_PARENT,
  	I_MUTEX_CHILD,

  	I_MUTEX_XATTR,

  	I_MUTEX_QUOTA
  };
  
  /*

   * NOTE: in a 32bit arch with a preemptable kernel and
   * an UP compile the i_size_read/write must be atomic
   * with respect to the local cpu (unlike with preempt disabled),
   * but they don't need to be atomic with respect to other cpus like in
   * true SMP (so they need either to either locally disable irq around
   * the read or for example on x86 they can be still implemented as a
   * cmpxchg8b without the need of the lock prefix). For SMP compiles
   * and 64bit archs it makes no difference if preempt is enabled or not.
   */

  static inline loff_t i_size_read(const struct inode *inode)

  {
  #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
  	loff_t i_size;
  	unsigned int seq;
  
  	do {
  		seq = read_seqcount_begin(&inode->i_size_seqcount);
  		i_size = inode->i_size;
  	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
  	return i_size;
  #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
  	loff_t i_size;
  
  	preempt_disable();
  	i_size = inode->i_size;
  	preempt_enable();
  	return i_size;
  #else
  	return inode->i_size;
  #endif
  }

  /*
   * NOTE: unlike i_size_read(), i_size_write() does need locking around it
   * (normally i_mutex), otherwise on 32bit/SMP an update of i_size_seqcount
   * can be lost, resulting in subsequent i_size_read() calls spinning forever.
   */

  static inline void i_size_write(struct inode *inode, loff_t i_size)
  {
  #if BITS_PER_LONG==32 && defined(CONFIG_SMP)
  	write_seqcount_begin(&inode->i_size_seqcount);
  	inode->i_size = i_size;
  	write_seqcount_end(&inode->i_size_seqcount);
  #elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
  	preempt_disable();
  	inode->i_size = i_size;
  	preempt_enable();
  #else
  	inode->i_size = i_size;
  #endif
  }

  static inline unsigned iminor(const struct inode *inode)

  {
  	return MINOR(inode->i_rdev);
  }

  static inline unsigned imajor(const struct inode *inode)

  {
  	return MAJOR(inode->i_rdev);
  }
  
  extern struct block_device *I_BDEV(struct inode *inode);
  
  struct fown_struct {
  	rwlock_t lock;          /* protects pid, uid, euid fields */

  	struct pid *pid;	/* pid or -pgrp where SIGIO should be sent */
  	enum pid_type pid_type;	/* Kind of process group SIGIO should be sent to */

  	uid_t uid, euid;	/* uid/euid of process setting the owner */

  	int signum;		/* posix.1b rt signal to be delivered on IO */
  };
  
  /*
   * Track a single file's readahead state
   */
  struct file_ra_state {

  	pgoff_t start;			/* where readahead started */
  	unsigned int size;		/* # of readahead pages */
  	unsigned int async_size;	/* do asynchronous readahead when

  					   there are only # of pages ahead */

  	unsigned int ra_pages;		/* Maximum readahead window */

  	unsigned int mmap_miss;		/* Cache miss stat for mmap accesses */

  	loff_t prev_pos;		/* Cache last read() position */

  };

  /*

   * Check if @index falls in the readahead windows.
   */
  static inline int ra_has_index(struct file_ra_state *ra, pgoff_t index)
  {

  	return (index >= ra->start &&
  		index <  ra->start + ra->size);

  }

  #define FILE_MNT_WRITE_TAKEN	1
  #define FILE_MNT_WRITE_RELEASED	2

  struct file {

  	/*
  	 * fu_list becomes invalid after file_free is called and queued via
  	 * fu_rcuhead for RCU freeing
  	 */
  	union {
  		struct list_head	fu_list;
  		struct rcu_head 	fu_rcuhead;
  	} f_u;

  	struct path		f_path;
  #define f_dentry	f_path.dentry
  #define f_vfsmnt	f_path.mnt

  	const struct file_operations	*f_op;

  
  	/*
  	 * Protects f_ep_links, f_flags, f_pos vs i_size in lseek SEEK_CUR.
  	 * Must not be taken from IRQ context.
  	 */
  	spinlock_t		f_lock;

  #ifdef CONFIG_SMP
  	int			f_sb_list_cpu;
  #endif

  	atomic_long_t		f_count;

  	unsigned int 		f_flags;

  	fmode_t			f_mode;

  	loff_t			f_pos;
  	struct fown_struct	f_owner;

  	const struct cred	*f_cred;

  	struct file_ra_state	f_ra;

  	u64			f_version;

  #ifdef CONFIG_SECURITY

  	void			*f_security;

  #endif

  	/* needed for tty driver, and maybe others */
  	void			*private_data;
  
  #ifdef CONFIG_EPOLL
  	/* Used by fs/eventpoll.c to link all the hooks to this file */
  	struct list_head	f_ep_links;

  #endif /* #ifdef CONFIG_EPOLL */
  	struct address_space	*f_mapping;

  #ifdef CONFIG_DEBUG_WRITECOUNT
  	unsigned long f_mnt_write_state;
  #endif

  };

  struct file_handle {
  	__u32 handle_bytes;
  	int handle_type;
  	/* file identifier */
  	unsigned char f_handle[0];
  };

  #define get_file(x)	atomic_long_inc(&(x)->f_count)

  #define fput_atomic(x)	atomic_long_add_unless(&(x)->f_count, -1, 1)

  #define file_count(x)	atomic_long_read(&(x)->f_count)

  #ifdef CONFIG_DEBUG_WRITECOUNT
  static inline void file_take_write(struct file *f)
  {
  	WARN_ON(f->f_mnt_write_state != 0);
  	f->f_mnt_write_state = FILE_MNT_WRITE_TAKEN;
  }
  static inline void file_release_write(struct file *f)
  {
  	f->f_mnt_write_state |= FILE_MNT_WRITE_RELEASED;
  }
  static inline void file_reset_write(struct file *f)
  {
  	f->f_mnt_write_state = 0;
  }
  static inline void file_check_state(struct file *f)
  {
  	/*
  	 * At this point, either both or neither of these bits
  	 * should be set.
  	 */
  	WARN_ON(f->f_mnt_write_state == FILE_MNT_WRITE_TAKEN);
  	WARN_ON(f->f_mnt_write_state == FILE_MNT_WRITE_RELEASED);
  }
  static inline int file_check_writeable(struct file *f)
  {
  	if (f->f_mnt_write_state == FILE_MNT_WRITE_TAKEN)
  		return 0;
  	printk(KERN_WARNING "writeable file with no "
  			    "mnt_want_write()
  ");
  	WARN_ON(1);
  	return -EINVAL;
  }
  #else /* !CONFIG_DEBUG_WRITECOUNT */
  static inline void file_take_write(struct file *filp) {}
  static inline void file_release_write(struct file *filp) {}
  static inline void file_reset_write(struct file *filp) {}
  static inline void file_check_state(struct file *filp) {}
  static inline int file_check_writeable(struct file *filp)
  {
  	return 0;
  }
  #endif /* CONFIG_DEBUG_WRITECOUNT */

  #define	MAX_NON_LFS	((1UL<<31) - 1)
  
  /* Page cache limit. The filesystems should put that into their s_maxbytes 
     limits, otherwise bad things can happen in VM. */ 
  #if BITS_PER_LONG==32
  #define MAX_LFS_FILESIZE	(((u64)PAGE_CACHE_SIZE << (BITS_PER_LONG-1))-1) 
  #elif BITS_PER_LONG==64
  #define MAX_LFS_FILESIZE 	0x7fffffffffffffffUL
  #endif
  
  #define FL_POSIX	1
  #define FL_FLOCK	2
  #define FL_ACCESS	8	/* not trying to lock, just looking */

  #define FL_EXISTS	16	/* when unlocking, test for existence */

  #define FL_LEASE	32	/* lease held on this file */

  #define FL_CLOSE	64	/* unlock on close */

  #define FL_SLEEP	128	/* A blocking lock */

  #define FL_DOWNGRADE_PENDING	256 /* Lease is being downgraded */
  #define FL_UNLOCK_PENDING	512 /* Lease is being broken */

  
  /*

   * Special return value from posix_lock_file() and vfs_lock_file() for
   * asynchronous locking.
   */
  #define FILE_LOCK_DEFERRED 1
  
  /*

   * The POSIX file lock owner is determined by
   * the "struct files_struct" in the thread group
   * (or NULL for no owner - BSD locks).
   *
   * Lockd stuffs a "host" pointer into this.
   */
  typedef struct files_struct *fl_owner_t;
  
  struct file_lock_operations {

  	void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
  	void (*fl_release_private)(struct file_lock *);
  };
  
  struct lock_manager_operations {

  	int (*lm_compare_owner)(struct file_lock *, struct file_lock *);
  	void (*lm_notify)(struct file_lock *);	/* unblock callback */
  	int (*lm_grant)(struct file_lock *, struct file_lock *, int);
  	void (*lm_release_private)(struct file_lock *);
  	void (*lm_break)(struct file_lock *);
  	int (*lm_change)(struct file_lock **, int);

  };

  struct lock_manager {
  	struct list_head list;
  };
  
  void locks_start_grace(struct lock_manager *);
  void locks_end_grace(struct lock_manager *);
  int locks_in_grace(void);

  /* that will die - we need it for nfs_lock_info */
  #include <linux/nfs_fs_i.h>
  
  struct file_lock {
  	struct file_lock *fl_next;	/* singly linked list for this inode  */
  	struct list_head fl_link;	/* doubly linked list of all locks */
  	struct list_head fl_block;	/* circular list of blocked processes */
  	fl_owner_t fl_owner;

  	unsigned int fl_flags;

  	unsigned char fl_type;

  	unsigned int fl_pid;

  	struct pid *fl_nspid;

  	wait_queue_head_t fl_wait;
  	struct file *fl_file;

  	loff_t fl_start;
  	loff_t fl_end;
  
  	struct fasync_struct *	fl_fasync; /* for lease break notifications */

  	/* for lease breaks: */
  	unsigned long fl_break_time;
  	unsigned long fl_downgrade_time;

  	const struct file_lock_operations *fl_ops;	/* Callbacks for filesystems */

  	const struct lock_manager_operations *fl_lmops;	/* Callbacks for lockmanagers */

  	union {
  		struct nfs_lock_info	nfs_fl;

  		struct nfs4_lock_info	nfs4_fl;

  		struct {
  			struct list_head link;	/* link in AFS vnode's pending_locks list */
  			int state;		/* state of grant or error if -ve */
  		} afs;

  	} fl_u;
  };
  
  /* The following constant reflects the upper bound of the file/locking space */
  #ifndef OFFSET_MAX
  #define INT_LIMIT(x)	(~((x)1 << (sizeof(x)*8 - 1)))
  #define OFFSET_MAX	INT_LIMIT(loff_t)
  #define OFFT_OFFSET_MAX	INT_LIMIT(off_t)
  #endif

  #include <linux/fcntl.h>

  extern void send_sigio(struct fown_struct *fown, int fd, int band);

  #ifdef CONFIG_FILE_LOCKING

  extern int fcntl_getlk(struct file *, struct flock __user *);

  extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
  			struct flock __user *);

  
  #if BITS_PER_LONG == 32
  extern int fcntl_getlk64(struct file *, struct flock64 __user *);

  extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
  			struct flock64 __user *);

  #endif

  extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
  extern int fcntl_getlease(struct file *filp);
  
  /* fs/locks.c */

  void locks_free_lock(struct file_lock *fl);

  extern void locks_init_lock(struct file_lock *);

  extern struct file_lock * locks_alloc_lock(void);

  extern void locks_copy_lock(struct file_lock *, struct file_lock *);

  extern void __locks_copy_lock(struct file_lock *, const struct file_lock *);

  extern void locks_remove_posix(struct file *, fl_owner_t);
  extern void locks_remove_flock(struct file *);

  extern void locks_release_private(struct file_lock *);

  extern void posix_test_lock(struct file *, struct file_lock *);

  extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);

  extern int posix_lock_file_wait(struct file *, struct file_lock *);

  extern int posix_unblock_lock(struct file *, struct file_lock *);

  extern int vfs_test_lock(struct file *, struct file_lock *);

  extern int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *);

  extern int vfs_cancel_lock(struct file *filp, struct file_lock *fl);

  extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
  extern int __break_lease(struct inode *inode, unsigned int flags);
  extern void lease_get_mtime(struct inode *, struct timespec *time);

  extern int generic_setlease(struct file *, long, struct file_lock **);

  extern int vfs_setlease(struct file *, long, struct file_lock **);

  extern int lease_modify(struct file_lock **, int);
  extern int lock_may_read(struct inode *, loff_t start, unsigned long count);
  extern int lock_may_write(struct inode *, loff_t start, unsigned long count);

  extern void lock_flocks(void);
  extern void unlock_flocks(void);

  #else /* !CONFIG_FILE_LOCKING */

  static inline int fcntl_getlk(struct file *file, struct flock __user *user)
  {
  	return -EINVAL;
  }
  
  static inline int fcntl_setlk(unsigned int fd, struct file *file,
  			      unsigned int cmd, struct flock __user *user)
  {
  	return -EACCES;
  }

  #if BITS_PER_LONG == 32

  static inline int fcntl_getlk64(struct file *file, struct flock64 __user *user)
  {
  	return -EINVAL;
  }
  
  static inline int fcntl_setlk64(unsigned int fd, struct file *file,
  				unsigned int cmd, struct flock64 __user *user)
  {
  	return -EACCES;
  }

  #endif

  static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
  {
  	return 0;
  }
  
  static inline int fcntl_getlease(struct file *filp)
  {
  	return 0;
  }
  
  static inline void locks_init_lock(struct file_lock *fl)
  {
  	return;
  }
  
  static inline void __locks_copy_lock(struct file_lock *new, struct file_lock *fl)
  {
  	return;
  }
  
  static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
  {
  	return;
  }
  
  static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
  {
  	return;
  }
  
  static inline void locks_remove_flock(struct file *filp)
  {
  	return;
  }
  
  static inline void posix_test_lock(struct file *filp, struct file_lock *fl)
  {
  	return;
  }
  
  static inline int posix_lock_file(struct file *filp, struct file_lock *fl,
  				  struct file_lock *conflock)
  {
  	return -ENOLCK;
  }
  
  static inline int posix_lock_file_wait(struct file *filp, struct file_lock *fl)
  {
  	return -ENOLCK;
  }
  
  static inline int posix_unblock_lock(struct file *filp,
  				     struct file_lock *waiter)
  {
  	return -ENOENT;
  }
  
  static inline int vfs_test_lock(struct file *filp, struct file_lock *fl)
  {
  	return 0;
  }
  
  static inline int vfs_lock_file(struct file *filp, unsigned int cmd,
  				struct file_lock *fl, struct file_lock *conf)
  {
  	return -ENOLCK;
  }
  
  static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
  {
  	return 0;
  }
  
  static inline int flock_lock_file_wait(struct file *filp,
  				       struct file_lock *request)
  {
  	return -ENOLCK;
  }
  
  static inline int __break_lease(struct inode *inode, unsigned int mode)
  {
  	return 0;
  }
  
  static inline void lease_get_mtime(struct inode *inode, struct timespec *time)
  {
  	return;
  }
  
  static inline int generic_setlease(struct file *filp, long arg,
  				    struct file_lock **flp)
  {
  	return -EINVAL;
  }
  
  static inline int vfs_setlease(struct file *filp, long arg,
  			       struct file_lock **lease)
  {
  	return -EINVAL;
  }
  
  static inline int lease_modify(struct file_lock **before, int arg)
  {
  	return -EINVAL;
  }
  
  static inline int lock_may_read(struct inode *inode, loff_t start,
  				unsigned long len)
  {
  	return 1;
  }
  
  static inline int lock_may_write(struct inode *inode, loff_t start,
  				 unsigned long len)
  {
  	return 1;
  }

  static inline void lock_flocks(void)
  {
  }
  
  static inline void unlock_flocks(void)
  {
  }

  #endif /* !CONFIG_FILE_LOCKING */

  
  struct fasync_struct {

  	spinlock_t		fa_lock;
  	int			magic;
  	int			fa_fd;
  	struct fasync_struct	*fa_next; /* singly linked list */
  	struct file		*fa_file;
  	struct rcu_head		fa_rcu;

  };
  
  #define FASYNC_MAGIC 0x4601
  
  /* SMP safe fasync helpers: */
  extern int fasync_helper(int, struct file *, int, struct fasync_struct **);

  extern struct fasync_struct *fasync_insert_entry(int, struct file *, struct fasync_struct **, struct fasync_struct *);
  extern int fasync_remove_entry(struct file *, struct fasync_struct **);
  extern struct fasync_struct *fasync_alloc(void);
  extern void fasync_free(struct fasync_struct *);

  /* can be called from interrupts */
  extern void kill_fasync(struct fasync_struct **, int, int);

  extern int __f_setown(struct file *filp, struct pid *, enum pid_type, int force);

  extern int f_setown(struct file *filp, unsigned long arg, int force);
  extern void f_delown(struct file *filp);

  extern pid_t f_getown(struct file *filp);

  extern int send_sigurg(struct fown_struct *fown);
  
  /*
   *	Umount options
   */
  
  #define MNT_FORCE	0x00000001	/* Attempt to forcibily umount */
  #define MNT_DETACH	0x00000002	/* Just detach from the tree */
  #define MNT_EXPIRE	0x00000004	/* Mark for expiry */

  #define UMOUNT_NOFOLLOW	0x00000008	/* Don't follow symlink on umount */
  #define UMOUNT_UNUSED	0x80000000	/* Flag guaranteed to be unused */

  
  extern struct list_head super_blocks;
  extern spinlock_t sb_lock;

  struct super_block {
  	struct list_head	s_list;		/* Keep this first */
  	dev_t			s_dev;		/* search index; _not_ kdev_t */

  	unsigned char		s_dirt;

  	unsigned char		s_blocksize_bits;
  	unsigned long		s_blocksize;

  	loff_t			s_maxbytes;	/* Max file size */

  	struct file_system_type	*s_type;

  	const struct super_operations	*s_op;

  	const struct dquot_operations	*dq_op;

  	const struct quotactl_ops	*s_qcop;

  	const struct export_operations *s_export_op;

  	unsigned long		s_flags;
  	unsigned long		s_magic;
  	struct dentry		*s_root;
  	struct rw_semaphore	s_umount;

  	struct mutex		s_lock;

  	int			s_count;

  	atomic_t		s_active;

  #ifdef CONFIG_SECURITY

  	void                    *s_security;

  #endif

  	const struct xattr_handler **s_xattr;

  
  	struct list_head	s_inodes;	/* all inodes */

  	struct hlist_bl_head	s_anon;		/* anonymous dentries for (nfs) exporting */

  #ifdef CONFIG_SMP
  	struct list_head __percpu *s_files;
  #else

  	struct list_head	s_files;

  #endif

  	/* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */

  	struct list_head	s_dentry_lru;	/* unused dentry lru */
  	int			s_nr_dentry_unused;	/* # of dentry on lru */

  	/* s_inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */
  	spinlock_t		s_inode_lru_lock ____cacheline_aligned_in_smp;

  	struct list_head	s_inode_lru;		/* unused inode lru */
  	int			s_nr_inodes_unused;	/* # of inodes on lru */

  	struct block_device	*s_bdev;

  	struct backing_dev_info *s_bdi;

  	struct mtd_info		*s_mtd;

  	struct list_head	s_instances;
  	struct quota_info	s_dquot;	/* Diskquota specific options */
  
  	int			s_frozen;
  	wait_queue_head_t	s_wait_unfrozen;
  
  	char s_id[32];				/* Informational name */

  	u8 s_uuid[16];				/* UUID */

  
  	void 			*s_fs_info;	/* Filesystem private info */

  	fmode_t			s_mode;

  	/* Granularity of c/m/atime in ns.
  	   Cannot be worse than a second */
  	u32		   s_time_gran;

  	/*
  	 * The next field is for VFS *only*. No filesystems have any business
  	 * even looking at it. You had been warned.
  	 */

  	struct mutex s_vfs_rename_mutex;	/* Kludge */

  	/*
  	 * Filesystem subtype.  If non-empty the filesystem type field
  	 * in /proc/mounts will be "type.subtype"
  	 */
  	char *s_subtype;

  
  	/*
  	 * Saved mount options for lazy filesystems using
  	 * generic_show_options()
  	 */

  	char __rcu *s_options;

  	const struct dentry_operations *s_d_op; /* default d_op for dentries */

  
  	/*
  	 * Saved pool identifier for cleancache (-1 means none)
  	 */
  	int cleancache_poolid;

  
  	struct shrinker s_shrink;	/* per-sb shrinker handle */

  };

  /* superblock cache pruning functions */
  extern void prune_icache_sb(struct super_block *sb, int nr_to_scan);
  extern void prune_dcache_sb(struct super_block *sb, int nr_to_scan);

  extern struct timespec current_fs_time(struct super_block *sb);
  
  /*
   * Snapshotting support.
   */
  enum {
  	SB_UNFROZEN = 0,
  	SB_FREEZE_WRITE	= 1,
  	SB_FREEZE_TRANS = 2,
  };
  
  #define vfs_check_frozen(sb, level) \
  	wait_event((sb)->s_wait_unfrozen, ((sb)->s_frozen < (level)))

  /*
   * until VFS tracks user namespaces for inodes, just make all files
   * belong to init_user_ns
   */
  extern struct user_namespace init_user_ns;
  #define inode_userns(inode) (&init_user_ns)

  extern bool inode_owner_or_capable(const struct inode *inode);

  /* not quite ready to be deprecated, but... */
  extern void lock_super(struct super_block *);
  extern void unlock_super(struct super_block *);

  
  /*
   * VFS helper functions..
   */
  extern int vfs_create(struct inode *, struct dentry *, int, struct nameidata *);
  extern int vfs_mkdir(struct inode *, struct dentry *, int);
  extern int vfs_mknod(struct inode *, struct dentry *, int, dev_t);

  extern int vfs_symlink(struct inode *, struct dentry *, const char *);

  extern int vfs_link(struct dentry *, struct inode *, struct dentry *);
  extern int vfs_rmdir(struct inode *, struct dentry *);
  extern int vfs_unlink(struct inode *, struct dentry *);
  extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
  
  /*
   * VFS dentry helper functions.
   */
  extern void dentry_unhash(struct dentry *dentry);
  
  /*

   * VFS file helper functions.
   */

  extern void inode_init_owner(struct inode *inode, const struct inode *dir,
  			mode_t mode);

  /*

   * VFS FS_IOC_FIEMAP helper definitions.
   */
  struct fiemap_extent_info {
  	unsigned int fi_flags;		/* Flags as passed from user */
  	unsigned int fi_extents_mapped;	/* Number of mapped extents */
  	unsigned int fi_extents_max;	/* Size of fiemap_extent array */

  	struct fiemap_extent __user *fi_extents_start; /* Start of
  							fiemap_extent array */

  };
  int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
  			    u64 phys, u64 len, u32 flags);
  int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
  
  /*

   * File types
   *
   * NOTE! These match bits 12..15 of stat.st_mode
   * (ie "(i_mode >> 12) & 15").
   */
  #define DT_UNKNOWN	0
  #define DT_FIFO		1
  #define DT_CHR		2
  #define DT_DIR		4
  #define DT_BLK		6
  #define DT_REG		8
  #define DT_LNK		10
  #define DT_SOCK		12
  #define DT_WHT		14

  /*
   * This is the "filldir" function type, used by readdir() to let
   * the kernel specify what kind of dirent layout it wants to have.
   * This allows the kernel to read directories into kernel space or
   * to have different dirent layouts depending on the binary type.
   */

  typedef int (*filldir_t)(void *, const char *, int, loff_t, u64, unsigned);

  struct block_device_operations;

  /* These macros are for out of kernel modules to test that
   * the kernel supports the unlocked_ioctl and compat_ioctl
   * fields in struct file_operations. */
  #define HAVE_COMPAT_IOCTL 1
  #define HAVE_UNLOCKED_IOCTL 1

  struct file_operations {
  	struct module *owner;
  	loff_t (*llseek) (struct file *, loff_t, int);
  	ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);

  	ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);

  	ssize_t (*aio_read) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
  	ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);

  	int (*readdir) (struct file *, void *, filldir_t);
  	unsigned int (*poll) (struct file *, struct poll_table_struct *);

  	long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
  	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
  	int (*mmap) (struct file *, struct vm_area_struct *);
  	int (*open) (struct inode *, struct file *);

  	int (*flush) (struct file *, fl_owner_t id);

  	int (*release) (struct inode *, struct file *);

  	int (*fsync) (struct file *, loff_t, loff_t, int datasync);

  	int (*aio_fsync) (struct kiocb *, int datasync);
  	int (*fasync) (int, struct file *, int);
  	int (*lock) (struct file *, int, struct file_lock *);

  	ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
  	unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
  	int (*check_flags)(int);

  	int (*flock) (struct file *, int, struct file_lock *);

  	ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
  	ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);

  	int (*setlease)(struct file *, long, struct file_lock **);

  	long (*fallocate)(struct file *file, int mode, loff_t offset,
  			  loff_t len);

  };
  
  struct inode_operations {

  	struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameidata *);

  	void * (*follow_link) (struct dentry *, struct nameidata *);

  	int (*permission) (struct inode *, int);

  	struct posix_acl * (*get_acl)(struct inode *, int);

  
  	int (*readlink) (struct dentry *, char __user *,int);
  	void (*put_link) (struct dentry *, struct nameidata *, void *);
  
  	int (*create) (struct inode *,struct dentry *,int, struct nameidata *);

  	int (*link) (struct dentry *,struct inode *,struct dentry *);
  	int (*unlink) (struct inode *,struct dentry *);
  	int (*symlink) (struct inode *,struct dentry *,const char *);
  	int (*mkdir) (struct inode *,struct dentry *,int);
  	int (*rmdir) (struct inode *,struct dentry *);
  	int (*mknod) (struct inode *,struct dentry *,int,dev_t);
  	int (*rename) (struct inode *, struct dentry *,
  			struct inode *, struct dentry *);

  	void (*truncate) (struct inode *);

  	int (*setattr) (struct dentry *, struct iattr *);
  	int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
  	int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
  	ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t);
  	ssize_t (*listxattr) (struct dentry *, char *, size_t);
  	int (*removexattr) (struct dentry *, const char *);

  	void (*truncate_range)(struct inode *, loff_t, loff_t);

  	int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
  		      u64 len);

  } ____cacheline_aligned;

  
  struct seq_file;

  ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,

  			      unsigned long nr_segs, unsigned long fast_segs,
  			      struct iovec *fast_pointer,
  			      struct iovec **ret_pointer,
  			      int check_access);

  extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
  extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
  extern ssize_t vfs_readv(struct file *, const struct iovec __user *,
  		unsigned long, loff_t *);
  extern ssize_t vfs_writev(struct file *, const struct iovec __user *,
  		unsigned long, loff_t *);

  struct super_operations {
     	struct inode *(*alloc_inode)(struct super_block *sb);
  	void (*destroy_inode)(struct inode *);

     	void (*dirty_inode) (struct inode *, int flags);

  	int (*write_inode) (struct inode *, struct writeback_control *wbc);

  	int (*drop_inode) (struct inode *);

  	void (*evict_inode) (struct inode *);

  	void (*put_super) (struct super_block *);
  	void (*write_super) (struct super_block *);
  	int (*sync_fs)(struct super_block *sb, int wait);

  	int (*freeze_fs) (struct super_block *);
  	int (*unfreeze_fs) (struct super_block *);

  	int (*statfs) (struct dentry *, struct kstatfs *);

  	int (*remount_fs) (struct super_block *, int *, char *);

  	void (*umount_begin) (struct super_block *);

  
  	int (*show_options)(struct seq_file *, struct vfsmount *);

  	int (*show_devname)(struct seq_file *, struct vfsmount *);
  	int (*show_path)(struct seq_file *, struct vfsmount *);

  	int (*show_stats)(struct seq_file *, struct vfsmount *);

  #ifdef CONFIG_QUOTA

  	ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
  	ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);

  #endif

  	int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);

  	int (*nr_cached_objects)(struct super_block *);
  	void (*free_cached_objects)(struct super_block *, int);

  };

  /*

   * Inode state bits.  Protected by inode->i_lock

   *
   * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
   * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
   *
   * Four bits define the lifetime of an inode.  Initially, inodes are I_NEW,
   * until that flag is cleared.  I_WILL_FREE, I_FREEING and I_CLEAR are set at
   * various stages of removing an inode.
   *

   * Two bits are used for locking and completion notification, I_NEW and I_SYNC.

   *

   * I_DIRTY_SYNC		Inode is dirty, but doesn't have to be written on
   *			fdatasync().  i_atime is the usual cause.

   * I_DIRTY_DATASYNC	Data-related inode changes pending. We keep track of
   *			these changes separately from I_DIRTY_SYNC so that we
   *			don't have to write inode on fdatasync() when only
   *			mtime has changed in it.

   * I_DIRTY_PAGES	Inode has dirty pages.  Inode itself may be clean.

   * I_NEW		Serves as both a mutex and completion notification.
   *			New inodes set I_NEW.  If two processes both create
   *			the same inode, one of them will release its inode and
   *			wait for I_NEW to be released before returning.
   *			Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
   *			also cause waiting on I_NEW, without I_NEW actually
   *			being set.  find_inode() uses this to prevent returning
   *			nearly-dead inodes.

   * I_WILL_FREE		Must be set when calling write_inode_now() if i_count
   *			is zero.  I_FREEING must be set when I_WILL_FREE is
   *			cleared.
   * I_FREEING		Set when inode is about to be freed but still has dirty
   *			pages or buffers attached or the inode itself is still
   *			dirty.

   * I_CLEAR		Added by end_writeback().  In this state the inode is clean

   *			and can be destroyed.  Inode keeps I_FREEING.

   *
   *			Inodes that are I_WILL_FREE, I_FREEING or I_CLEAR are
   *			prohibited for many purposes.  iget() must wait for
   *			the inode to be completely released, then create it
   *			anew.  Other functions will just ignore such inodes,

   *			if appropriate.  I_NEW is used for waiting.

   *

   * I_SYNC		Synchonized write of dirty inode data.  The bits is
   *			set during data writeback, and cleared with a wakeup
   *			on the bit address once it is done.

   *

   * I_REFERENCED		Marks the inode as recently references on the LRU list.
   *
   * I_DIO_WAKEUP		Never set.  Only used as a key for wait_on_bit().
   *

   * Q: What is the difference between I_WILL_FREE and I_FREEING?

   */

  #define I_DIRTY_SYNC		(1 << 0)
  #define I_DIRTY_DATASYNC	(1 << 1)
  #define I_DIRTY_PAGES		(1 << 2)

  #define __I_NEW			3
  #define I_NEW			(1 << __I_NEW)

  #define I_WILL_FREE		(1 << 4)
  #define I_FREEING		(1 << 5)
  #define I_CLEAR			(1 << 6)

  #define __I_SYNC		7

  #define I_SYNC			(1 << __I_SYNC)

  #define I_REFERENCED		(1 << 8)

  #define __I_DIO_WAKEUP		9
  #define I_DIO_WAKEUP		(1 << I_DIO_WAKEUP)

  
  #define I_DIRTY (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_PAGES)
  
  extern void __mark_inode_dirty(struct inode *, int);
  static inline void mark_inode_dirty(struct inode *inode)
  {
  	__mark_inode_dirty(inode, I_DIRTY);
  }
  
  static inline void mark_inode_dirty_sync(struct inode *inode)
  {
  	__mark_inode_dirty(inode, I_DIRTY_SYNC);
  }

  /**

   * set_nlink - directly set an inode's link count
   * @inode: inode
   * @nlink: new nlink (should be non-zero)
   *
   * This is a low-level filesystem helper to replace any
   * direct filesystem manipulation of i_nlink.
   */
  static inline void set_nlink(struct inode *inode, unsigned int nlink)
  {

  	inode->__i_nlink = nlink;

  }
  
  /**

   * inc_nlink - directly increment an inode's link count
   * @inode: inode
   *
   * This is a low-level filesystem helper to replace any
   * direct filesystem manipulation of i_nlink.  Currently,
   * it is only here for parity with dec_nlink().
   */

  static inline void inc_nlink(struct inode *inode)

  {

  	inode->__i_nlink++;

  }
  
  static inline void inode_inc_link_count(struct inode *inode)
  {
  	inc_nlink(inode);

  	mark_inode_dirty(inode);
  }

  /**
   * drop_nlink - directly drop an inode's link count
   * @inode: inode
   *
   * This is a low-level filesystem helper to replace any
   * direct filesystem manipulation of i_nlink.  In cases
   * where we are attempting to track writes to the
   * filesystem, a decrement to zero means an imminent
   * write when the file is truncated and actually unlinked
   * on the filesystem.
   */

  static inline void drop_nlink(struct inode *inode)

  {

  	inode->__i_nlink--;

  }

  /**
   * clear_nlink - directly zero an inode's link count
   * @inode: inode
   *
   * This is a low-level filesystem helper to replace any
   * direct filesystem manipulation of i_nlink.  See
   * drop_nlink() for why we care about i_nlink hitting zero.
   */

  static inline void clear_nlink(struct inode *inode)
  {

  	inode->__i_nlink = 0;

  }

  static inline void inode_dec_link_count(struct inode *inode)
  {
  	drop_nlink(inode);

  	mark_inode_dirty(inode);
  }

  /**
   * inode_inc_iversion - increments i_version
   * @inode: inode that need to be updated
   *
   * Every time the inode is modified, the i_version field will be incremented.
   * The filesystem has to be mounted with i_version flag
   */
  
  static inline void inode_inc_iversion(struct inode *inode)
  {
         spin_lock(&inode->i_lock);
         inode->i_version++;
         spin_unlock(&inode->i_lock);
  }

  extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry);

  static inline void file_accessed(struct file *file)
  {
  	if (!(file->f_flags & O_NOATIME))

  		touch_atime(file->f_path.mnt, file->f_path.dentry);

  }
  
  int sync_inode(struct inode *inode, struct writeback_control *wbc);

  int sync_inode_metadata(struct inode *inode, int wait);

  struct file_system_type {
  	const char *name;
  	int fs_flags;

  	struct dentry *(*mount) (struct file_system_type *, int,
  		       const char *, void *);

  	void (*kill_sb) (struct super_block *);
  	struct module *owner;
  	struct file_system_type * next;
  	struct list_head fs_supers;

  	struct lock_class_key s_lock_key;

  	struct lock_class_key s_umount_key;

  	struct lock_class_key s_vfs_rename_key;

  
  	struct lock_class_key i_lock_key;
  	struct lock_class_key i_mutex_key;

  	struct lock_class_key i_mutex_dir_key;

  };

  extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags,
  	void *data, int (*fill_super)(struct super_block *, void *, int));

  extern struct dentry *mount_bdev(struct file_system_type *fs_type,
  	int flags, const char *dev_name, void *data,
  	int (*fill_super)(struct super_block *, void *, int));

  extern struct dentry *mount_single(struct file_system_type *fs_type,
  	int flags, void *data,
  	int (*fill_super)(struct super_block *, void *, int));

  extern struct dentry *mount_nodev(struct file_system_type *fs_type,
  	int flags, void *data,
  	int (*fill_super)(struct super_block *, void *, int));

  extern struct dentry *mount_subtree(struct vfsmount *mnt, const char *path);

  void generic_shutdown_super(struct super_block *sb);
  void kill_block_super(struct super_block *sb);
  void kill_anon_super(struct super_block *sb);
  void kill_litter_super(struct super_block *sb);
  void deactivate_super(struct super_block *sb);

  void deactivate_locked_super(struct super_block *sb);

  int set_anon_super(struct super_block *s, void *data);

  int get_anon_bdev(dev_t *);
  void free_anon_bdev(dev_t);

  struct super_block *sget(struct file_system_type *type,
  			int (*test)(struct super_block *,void *),
  			int (*set)(struct super_block *,void *),
  			void *data);

  extern struct dentry *mount_pseudo(struct file_system_type *, char *,

  	const struct super_operations *ops,
  	const struct dentry_operations *dops,
  	unsigned long);

  static inline void sb_mark_dirty(struct super_block *sb)
  {
  	sb->s_dirt = 1;
  }
  static inline void sb_mark_clean(struct super_block *sb)
  {
  	sb->s_dirt = 0;
  }
  static inline int sb_is_dirty(struct super_block *sb)
  {
  	return sb->s_dirt;
  }

  /* Alas, no aliases. Too much hassle with bringing module.h everywhere */
  #define fops_get(fops) \
  	(((fops) && try_module_get((fops)->owner) ? (fops) : NULL))
  #define fops_put(fops) \
  	do { if (fops) module_put((fops)->owner); } while(0)
  
  extern int register_filesystem(struct file_system_type *);
  extern int unregister_filesystem(struct file_system_type *);

  extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
  #define kern_mount(type) kern_mount_data(type, NULL)

  extern void kern_unmount(struct vfsmount *mnt);

  extern int may_umount_tree(struct vfsmount *);
  extern int may_umount(struct vfsmount *);
  extern long do_mount(char *, char *, char *, unsigned long, void *);

  extern struct vfsmount *collect_mounts(struct path *);

  extern void drop_collected_mounts(struct vfsmount *);

  extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
  			  struct vfsmount *);

  extern int vfs_statfs(struct path *, struct kstatfs *);

  extern int user_statfs(const char __user *, struct kstatfs *);
  extern int fd_statfs(int, struct kstatfs *);

  extern int statfs_by_dentry(struct dentry *, struct kstatfs *);

  extern int freeze_super(struct super_block *super);
  extern int thaw_super(struct super_block *super);

  extern bool our_mnt(struct vfsmount *mnt);

  extern int current_umask(void);

  /* /sys/fs */

  extern struct kobject *fs_kobj;

  #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)

  extern int rw_verify_area(int, struct file *, loff_t *, size_t);

  #define FLOCK_VERIFY_READ  1
  #define FLOCK_VERIFY_WRITE 2

  #ifdef CONFIG_FILE_LOCKING

  extern int locks_mandatory_locked(struct inode *);
  extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
  
  /*
   * Candidates for mandatory locking have the setgid bit set
   * but no group execute bit -  an otherwise meaningless combination.
   */

  
  static inline int __mandatory_lock(struct inode *ino)
  {
  	return (ino->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID;
  }
  
  /*
   * ... and these candidates should be on MS_MANDLOCK mounted fs,
   * otherwise these will be advisory locks
   */
  
  static inline int mandatory_lock(struct inode *ino)
  {
  	return IS_MANDLOCK(ino) && __mandatory_lock(ino);
  }

  
  static inline int locks_verify_locked(struct inode *inode)
  {

  	if (mandatory_lock(inode))

  		return locks_mandatory_locked(inode);
  	return 0;
  }

  static inline int locks_verify_truncate(struct inode *inode,
  				    struct file *filp,
  				    loff_t size)
  {

  	if (inode->i_flock && mandatory_lock(inode))

  		return locks_mandatory_area(
  			FLOCK_VERIFY_WRITE, inode, filp,
  			size < inode->i_size ? size : inode->i_size,
  			(size < inode->i_size ? inode->i_size - size
  			 : size - inode->i_size)
  		);
  	return 0;
  }
  
  static inline int break_lease(struct inode *inode, unsigned int mode)
  {
  	if (inode->i_flock)
  		return __break_lease(inode, mode);
  	return 0;
  }

  #else /* !CONFIG_FILE_LOCKING */

  static inline int locks_mandatory_locked(struct inode *inode)
  {
  	return 0;
  }
  
  static inline int locks_mandatory_area(int rw, struct inode *inode,
  				       struct file *filp, loff_t offset,
  				       size_t count)
  {
  	return 0;
  }
  
  static inline int __mandatory_lock(struct inode *inode)
  {
  	return 0;
  }
  
  static inline int mandatory_lock(struct inode *inode)
  {
  	return 0;
  }
  
  static inline int locks_verify_locked(struct inode *inode)
  {
  	return 0;
  }
  
  static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
  					size_t size)
  {
  	return 0;
  }
  
  static inline int break_lease(struct inode *inode, unsigned int mode)
  {
  	return 0;
  }

  #endif /* CONFIG_FILE_LOCKING */

  
  /* fs/open.c */

  extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
  		       struct file *filp);

  extern int do_fallocate(struct file *file, int mode, loff_t offset,
  			loff_t len);

  extern long do_sys_open(int dfd, const char __user *filename, int flags,

  			int mode);

  extern struct file *filp_open(const char *, int, int);

  extern struct file *file_open_root(struct dentry *, struct vfsmount *,
  				   const char *, int);

  extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
  				 const struct cred *);

  extern int filp_close(struct file *, fl_owner_t id);
  extern char * getname(const char __user *);

  /* fs/ioctl.c */
  
  extern int ioctl_preallocate(struct file *filp, void __user *argp);

  /* fs/dcache.c */
  extern void __init vfs_caches_init_early(void);
  extern void __init vfs_caches_init(unsigned long);

  extern struct kmem_cache *names_cachep;

  #define __getname_gfp(gfp)	kmem_cache_alloc(names_cachep, (gfp))
  #define __getname()		__getname_gfp(GFP_KERNEL)
  #define __putname(name)		kmem_cache_free(names_cachep, (void *)(name))

  #ifndef CONFIG_AUDITSYSCALL
  #define putname(name)   __putname(name)
  #else
  extern void putname(const char *name);
  #endif

  #ifdef CONFIG_BLOCK

  extern int register_blkdev(unsigned int, const char *);

  extern void unregister_blkdev(unsigned int, const char *);

  extern struct block_device *bdget(dev_t);

  extern struct block_device *bdgrab(struct block_device *bdev);

  extern void bd_set_size(struct block_device *, loff_t size);
  extern void bd_forget(struct inode *inode);
  extern void bdput(struct block_device *);

  extern void invalidate_bdev(struct block_device *);
  extern int sync_blockdev(struct block_device *bdev);
  extern struct super_block *freeze_bdev(struct block_device *);

  extern void emergency_thaw_all(void);

  extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
  extern int fsync_bdev(struct block_device *);

  #else
  static inline void bd_forget(struct inode *inode) {}

  static inline int sync_blockdev(struct block_device *bdev) { return 0; }
  static inline void invalidate_bdev(struct block_device *bdev) {}
  
  static inline struct super_block *freeze_bdev(struct block_device *sb)
  {
  	return NULL;
  }
  
  static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb)
  {
  	return 0;
  }

  #endif

  extern int sync_filesystem(struct super_block *);

  extern const struct file_operations def_blk_fops;

  extern const struct file_operations def_chr_fops;
  extern const struct file_operations bad_sock_fops;
  extern const struct file_operations def_fifo_fops;

  #ifdef CONFIG_BLOCK

  extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);

  extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);