Cross-Referenced Linux and Device Driver Code

   #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>
  
  /*
   * 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
  extern int sysctl_nr_open;
  #define INR_OPEN 1024           /* Initial setting 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_MAX        SEEK_END
  
  /* And dynamically-tunable limits and defaults: */
  struct files_stat_struct {
          int nr_files;           /* read only */
          int nr_free_files;      /* read only */
          int max_files;          /* tunable */
  };
  extern struct files_stat_struct files_stat;
  extern int get_max_files(void);
  
  struct inodes_stat_t {
          int nr_inodes;
          int nr_unused;
          int dummy[5];           /* padding for sysctl ABI compatibility */
  };
  extern struct inodes_stat_t inodes_stat;
  
  extern int leases_enable, lease_break_time;
  
  #ifdef CONFIG_DNOTIFY
  extern int dir_notify_enable;
  #endif
  
  #define NR_FILE  8192   /* this can well be larger on a larger system */
  
  #define MAY_EXEC 1
  #define MAY_WRITE 2
  #define MAY_READ 4
  #define MAY_APPEND 8
  
  #define FMODE_READ 1
  #define FMODE_WRITE 2
  
  /* Internal kernel extensions */
  #define FMODE_LSEEK     4
  #define FMODE_PREAD     8
  #define FMODE_PWRITE    FMODE_PREAD     /* These go hand in hand */
  
  /* File is being opened for execution. Primary users of this flag are
     distributed filesystems that can use it to achieve correct ETXTBUSY
     behavior for cross-node execution/opening_for_writing of files */
  #define FMODE_EXEC      16
  
  #define RW_MASK         1
  #define RWA_MASK        2
  #define READ 0
  #define WRITE 1
  #define READA 2         /* read-ahead  - don't block if no resources */
  #define SWRITE 3        /* for ll_rw_block() - wait for buffer lock */
  #define READ_SYNC       (READ | (1 << BIO_RW_SYNC))
  #define READ_META       (READ | (1 << BIO_RW_META))
  #define WRITE_SYNC      (WRITE | (1 << BIO_RW_SYNC))
  #define WRITE_BARRIER   ((1 << BIO_RW) | (1 << BIO_RW_BARRIER))
  
  #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_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)
 
 /*
  * 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 */
 
 /*
  * 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)
 
 /* 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 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 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_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_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/types.h>
 #include <linux/kdev_t.h>
 #include <linux/dcache.h>
 #include <linux/namei.h>
 #include <linux/stat.h>
 #include <linux/cache.h>
 #include <linux/kobject.h>
 #include <linux/list.h>
 #include <linux/percpu_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/srcu.h>
 
 #include <asm/atomic.h>
 #include <asm/semaphore.h>
 #include <asm/byteorder.h>
 
 struct export_operations;
 struct hd_geometry;
 struct iovec;
 struct nameidata;
 struct kiocb;
 struct pipe_inode_info;
 struct poll_table_struct;
 struct kstatfs;
 struct vm_area_struct;
 struct vfsmount;
 
 extern void __init inode_init(void);
 extern void __init inode_init_early(void);
 extern void __init mnt_init(void);
 extern void __init files_init(unsigned long);
 
 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);
 
 /*
  * Attribute flags.  These should be or-ed together to figure out what
  * has been changed!
  */
 #define ATTR_MODE       1
 #define ATTR_UID        2
 #define ATTR_GID        4
 #define ATTR_SIZE       8
 #define ATTR_ATIME      16
 #define ATTR_MTIME      32
 #define ATTR_CTIME      64
 #define ATTR_ATIME_SET  128
 #define ATTR_MTIME_SET  256
 #define ATTR_FORCE      512     /* Not a change, but a change it */
 #define ATTR_ATTR_FLAG  1024
 #define ATTR_KILL_SUID  2048
 #define ATTR_KILL_SGID  4096
 #define ATTR_FILE       8192
 #define ATTR_KILL_PRIV  16384
 #define ATTR_OPEN       32768   /* Truncating from open(O_TRUNC) */
 
 /*
  * 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 auxilary 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 */
 
 /*
  * 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;
 }
 
 
 struct address_space_operations {
         int (*writepage)(struct page *page, struct writeback_control *wbc);
         int (*readpage)(struct file *, struct page *);
         void (*sync_page)(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);
 
         /*
          * ext3 requires that a successful prepare_write() call be followed
          * by a commit_write() call - they must be balanced
          */
         int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
         int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
 
         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);
         ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
                         loff_t offset, unsigned long nr_segs);
         struct page* (*get_xip_page)(struct address_space *, sector_t,
                         int);
         /* migrate the contents of a page to the specified target */
         int (*migratepage) (struct address_space *,
                         struct page *, struct page *);
         int (*launder_page) (struct page *);
 };
 
 /*
  * 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              priv_lock;      /* spinlock protecting various stuffs */
         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 */
         spinlock_t              i_mmap_lock;    /* protect tree, count, list */
         unsigned int            truncate_count; /* Cover race condition with truncate */
         atomic_long_t           __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 signficant bit
          * of struct page's "mapping" pointer be used for PAGE_MAPPING_ANON.
          */
 
 static inline void mapping_nrpages_init(struct address_space *mapping)
 {
         mapping->__nrpages = (atomic_long_t)ATOMIC_LONG_INIT(0);
 }
 
 static inline unsigned long mapping_nrpages(struct address_space *mapping)
 {
         return (unsigned long)atomic_long_read(&mapping->__nrpages);
 }
 
 static inline void mapping_nrpages_inc(struct address_space *mapping)
 {
         atomic_long_inc(&mapping->__nrpages);
 }
 
 static inline void mapping_nrpages_dec(struct address_space *mapping)
 {
         atomic_long_dec(&mapping->__nrpages);
 }
 
 struct block_device {
         dev_t                   bd_dev;  /* not a kdev_t - it's a search key */
         struct inode *          bd_inode;       /* will die */
         int                     bd_openers;
         struct mutex            bd_mutex;       /* open/close mutex */
         struct semaphore        bd_mount_sem;
         struct list_head        bd_inodes;
         void *                  bd_holder;
         int                     bd_holders;
 #ifdef CONFIG_SYSFS
         struct list_head        bd_holder_list;
 #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;
         struct backing_dev_info *bd_inode_backing_dev_info;
         /*
          * 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;
 };
 
 /*
  * Radix-tree tags, for tagging dirty and writeback pages within the pagecache
  * radix trees
  */
 #define PAGECACHE_TAG_DIRTY     0
 #define PAGECACHE_TAG_WRITEBACK 1
 
 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 inode {
         struct hlist_node       i_hash;
         struct list_head        i_list;
         struct list_head        i_sb_list;
         struct list_head        i_dentry;
         unsigned long           i_ino;
         atomic_t                i_count;
         unsigned int            i_nlink;
         uid_t                   i_uid;
         gid_t                   i_gid;
         dev_t                   i_rdev;
         u64                     i_version;
         loff_t                  i_size;
 #ifdef __NEED_I_SIZE_ORDERED
         seqcount_t              i_size_seqcount;
 #endif
         struct timespec         i_atime;
         struct timespec         i_mtime;
         struct timespec         i_ctime;
         unsigned int            i_blkbits;
         blkcnt_t                i_blocks;
         unsigned short          i_bytes;
         umode_t                 i_mode;
         spinlock_t              i_lock; /* i_blocks, i_bytes, maybe i_size */
         struct mutex            i_mutex;
         struct compat_rw_semaphore      i_alloc_sem;
         const struct inode_operations   *i_op;
         const struct file_operations    *i_fop; /* former ->i_op->default_file_ops */
         struct super_block      *i_sb;
         struct file_lock        *i_flock;
         struct address_space    *i_mapping;
         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;
         };
         int                     i_cindex;
 
         __u32                   i_generation;
 
 #ifdef CONFIG_DNOTIFY
         unsigned long           i_dnotify_mask; /* Directory notify events */
         struct dnotify_struct   *i_dnotify; /* for directory notifications */
 #endif
 
 #ifdef CONFIG_INOTIFY
         struct list_head        inotify_watches; /* watches on this inode */
         struct mutex            inotify_mutex;  /* protects the watches list */
 #endif
 
         unsigned long           i_state;
         unsigned long           dirtied_when;   /* jiffies of first dirtying */
 
         unsigned int            i_flags;
 
         atomic_t                i_writecount;
 #ifdef CONFIG_SECURITY
         void                    *i_security;
 #endif
         void                    *i_private; /* fs or device private pointer */
 };
 
 /*
  * 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
 };
 
 extern void inode_double_lock(struct inode *inode1, struct inode *inode2);
 extern void inode_double_unlock(struct inode *inode1, struct inode *inode2);
 
 /*
  * 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 */
         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);
 }
 
 struct file {
         struct {
                 struct lock_list_head   fu_llist;
                 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;
         atomic_t                f_count;
         unsigned int            f_flags;
         mode_t                  f_mode;
         loff_t                  f_pos;
         struct fown_struct      f_owner;
         unsigned int            f_uid, f_gid;
         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;
         spinlock_t              f_ep_lock;
 #endif /* #ifdef CONFIG_EPOLL */
         struct address_space    *f_mapping;
 };
 
 #define get_file(x)     atomic_inc(&(x)->f_count)
 #define file_count(x)   atomic_read(&(x)->f_count)
 
 #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 */
 
 /*
  * 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_insert)(struct file_lock *);  /* lock insertion callback */
         void (*fl_remove)(struct file_lock *);  /* lock removal callback */
         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
         void (*fl_release_private)(struct file_lock *);
 };
 
 struct lock_manager_operations {
         int (*fl_compare_owner)(struct file_lock *, struct file_lock *);
         void (*fl_notify)(struct file_lock *);  /* unblock callback */
         int (*fl_grant)(struct file_lock *, struct file_lock *, int);
         void (*fl_copy_lock)(struct file_lock *, struct file_lock *);
         void (*fl_release_private)(struct file_lock *);
         void (*fl_break)(struct file_lock *);
         int (*fl_mylease)(struct file_lock *, struct file_lock *);
         int (*fl_change)(struct file_lock **, int);
 };
 
 /* 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_pid;
         struct pid *fl_nspid;
         wait_queue_head_t fl_wait;
         struct file *fl_file;
         unsigned char fl_flags;
         unsigned char fl_type;
         loff_t fl_start;
         loff_t fl_end;
 
         struct fasync_struct *  fl_fasync; /* for lease break notifications */
         unsigned long fl_break_time;    /* for nonblocking lease breaks */
 
         struct file_lock_operations *fl_ops;    /* Callbacks for filesystems */
         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 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 void send_sigio(struct fown_struct *fown, int fd, int band);
 extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
 extern int fcntl_getlease(struct file *filp);
 
 /* fs/sync.c */
 extern int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
                         loff_t endbyte, unsigned int flags);
 
 /* fs/locks.c */
 extern void locks_init_lock(struct file_lock *);
 extern void locks_copy_lock(struct file_lock *, struct file_lock *);
 extern void locks_remove_posix(struct file *, fl_owner_t);
 extern void locks_remove_flock(struct file *);
 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 struct seq_operations locks_seq_operations;
 
 struct fasync_struct {
         int     magic;
         int     fa_fd;
         struct  fasync_struct   *fa_next; /* singly linked list */
         struct  file            *fa_file;
 };
 
 #define FASYNC_MAGIC 0x4601
 
 /* SMP safe fasync helpers: */
 extern int fasync_helper(int, struct file *, int, struct fasync_struct **);
 /* can be called from interrupts */
 extern void kill_fasync(struct fasync_struct **, int, int);
 /* only for net: no internal synchronization */
 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 */
 
 extern struct list_head super_blocks;
 extern spinlock_t sb_lock;
 
 #define S_BIAS (1<<30)
 struct super_block {
         struct list_head        s_list;         /* Keep this first */
         dev_t                   s_dev;          /* search index; _not_ kdev_t */
         unsigned long           s_blocksize;
         unsigned char           s_blocksize_bits;
         unsigned char           s_dirt;
         unsigned long long      s_maxbytes;     /* Max file size */
         struct file_system_type *s_type;
         const struct super_operations   *s_op;
         struct dquot_operations *dq_op;
         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;
         int                     s_syncing;
         int                     s_need_sync_fs;
         atomic_t                s_active;
 #ifdef CONFIG_SECURITY
         void                    *s_security;
 #endif
         struct xattr_handler    **s_xattr;
 
         struct list_head        s_inodes;       /* all inodes */
         struct list_head        s_dirty;        /* dirty inodes */
         struct list_head        s_io;           /* parked for writeback */
         struct list_head        s_more_io;      /* parked for more writeback */
         struct hlist_head       s_anon;         /* anonymous dentries for (nfs) exporting */
         struct percpu_list      s_files;
         struct qrcu_struct      s_qrcu;
 
         struct block_device     *s_bdev;
         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 */
 
         void                    *s_fs_info;     /* Filesystem private info */
 
         /*
          * 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 */
 
         /* Granularity of c/m/atime in ns.
            Cannot be worse than a second */
         u32                s_time_gran;
 
         /*
          * 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 *s_options;
 };
 
 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)))
 
 #define get_fs_excl() atomic_inc(&current->fs_excl)
 #define put_fs_excl() atomic_dec(&current->fs_excl)
 #define has_fs_excl() atomic_read(&current->fs_excl)
 
 #define is_owner_or_cap(inode)  \
         ((current->fsuid == (inode)->i_uid) || capable(CAP_FOWNER))
 
 /* 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_permission(struct nameidata *, int);
 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 *, int);
 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 int file_permission(struct file *, int);
 
 /*
  * 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
 
 #define OSYNC_METADATA  (1<<0)
 #define OSYNC_DATA      (1<<1)
 #define OSYNC_INODE     (1<<2)
 int generic_osync_inode(struct inode *, struct address_space *, int);
 
 /*
  * 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 {
         int (*open) (struct inode *, struct file *);
         int (*release) (struct inode *, struct file *);
         int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
         long (*unlocked_ioctl) (struct file *, unsigned, unsigned long);
         long (*compat_ioctl) (struct file *, unsigned, unsigned long);
         int (*direct_access) (struct block_device *, sector_t, unsigned long *);
         int (*media_changed) (struct gendisk *);
         int (*revalidate_disk) (struct gendisk *);
         int (*getgeo)(struct block_device *, struct hd_geometry *);
         struct module *owner;
 };
 
 /*
  * "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);
 
 /* 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
 
 /*
  * NOTE:
  * read, write, poll, fsync, readv, writev, unlocked_ioctl and compat_ioctl
  * can be called without the big kernel lock held in all filesystems.
  */
 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 *);
         int (*ioctl) (struct inode *, struct file *, unsigned int, unsigned long);
         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 *, struct dentry *, 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 (*dir_notify)(struct file *filp, unsigned long arg);
         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 **);
 };
 
 struct inode_operations {
         int (*create) (struct inode *,struct dentry *,int, struct nameidata *);
         struct dentry * (*lookup) (struct inode *,struct dentry *, 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 *);
         int (*readlink) (struct dentry *, char __user *,int);
         void * (*follow_link) (struct dentry *, struct nameidata *);
         void (*put_link) (struct dentry *, struct nameidata *, void *);
         void (*truncate) (struct inode *);
         int (*permission) (struct inode *, int, struct nameidata *);
         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);
         long (*fallocate)(struct inode *inode, int mode, loff_t offset,
                           loff_t len);
 };
 
 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);
 
 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 *);
 
 /*
  * NOTE: write_inode, delete_inode, clear_inode, put_inode can be called
  * without the big kernel lock held in all filesystems.
  */
 struct super_operations {
         struct inode *(*alloc_inode)(struct super_block *sb);
         void (*destroy_inode)(struct inode *);
 
         void (*dirty_inode) (struct inode *);
         int (*write_inode) (struct inode *, int);
         void (*put_inode) (struct inode *);
         void (*drop_inode) (struct inode *);
         void (*delete_inode) (struct inode *);
         void (*put_super) (struct super_block *);
         void (*write_super) (struct super_block *);
         int (*sync_fs)(struct super_block *sb, int wait);
         void (*write_super_lockfs) (struct super_block *);
         void (*unlockfs) (struct super_block *);
         int (*statfs) (struct dentry *, struct kstatfs *);
         int (*remount_fs) (struct super_block *, int *, char *);
         void (*clear_inode) (struct inode *);
         void (*umount_begin) (struct vfsmount *, int);
 
         int (*show_options)(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
 };
 
 /*
  * Inode state bits.  Protected by inode_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_LOCK 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                get_new_inode() sets i_state to I_LOCK|I_NEW.  Both
  *                      are cleared by unlock_new_inode(), called from iget().
  * 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              Set by clear_inode().  In this state the inode is clean
  *                      and can be destroyed.
  *
  *                      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_LOCK is used for waiting.
  *
  * I_LOCK               Serves as both a mutex and completion notification.
  *                      New inodes set I_LOCK.  If two processes both create
  *                      the same inode, one of them will release its inode and
  *                      wait for I_LOCK to be released before returning.
  *                      Inodes in I_WILL_FREE, I_FREEING or I_CLEAR state can
  *                      also cause waiting on I_LOCK, without I_LOCK actually
  *                      being set.  find_inode() uses this to prevent returning
  *                      nearly-dead inodes.
  * I_SYNC               Similar to I_LOCK, but limited in scope to writeback
  *                      of inode dirty data.  Having a separate lock for this
  *                      purpose reduces latency and prevents some filesystem-
  *                      specific deadlocks.
  *
  * Q: What is the difference between I_WILL_FREE and I_FREEING?
  * Q: igrab() only checks on (I_FREEING|I_WILL_FREE).  Should it also check on
  *    I_CLEAR?  If not, why?
  */
 #define I_DIRTY_SYNC            1
 #define I_DIRTY_DATASYNC        2
 #define I_DIRTY_PAGES           4
 #define I_NEW                   8
 #define I_WILL_FREE             16
 #define I_FREEING               32
 #define I_CLEAR                 64
 #define __I_LOCK                7
 #define I_LOCK                  (1 << __I_LOCK)
 #define __I_SYNC                8
 #define I_SYNC                  (1 << __I_SYNC)
 
 #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);
 }
 
 /**
  * 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);
 
 struct file_system_type {
         const char *name;
         int fs_flags;
         int (*get_sb) (struct file_system_type *, int,
                        const char *, void *, struct vfsmount *);
         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 i_lock_key;
         struct lock_class_key i_mutex_key;
         struct lock_class_key i_mutex_dir_key;
         struct lock_class_key i_alloc_sem_key;
 };
 
 extern int get_sb_bdev(struct file_system_type *fs_type,
         int flags, const char *dev_name, void *data,
         int (*fill_super)(struct super_block *, void *, int),
         struct vfsmount *mnt);
 extern int get_sb_single(struct file_system_type *fs_type,
         int flags, void *data,
         int (*fill_super)(struct super_block *, void *, int),
         struct vfsmount *mnt);
 extern int get_sb_nodev(struct file_system_type *fs_type,
         int flags, void *data,
         int (*fill_super)(struct super_block *, void *, int),
         struct vfsmount *mnt);
 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);
 int set_anon_super(struct super_block *s, void *data);
 struct super_block *sget(struct file_system_type *type,
                         int (*test)(struct super_block *,void *),
                         int (*set)(struct super_block *,void *),
                         void *data);
 extern int get_sb_pseudo(struct file_system_type *, char *,
         const struct super_operations *ops, unsigned long,
         struct vfsmount *mnt);
 extern int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb);
 int __put_super(struct super_block *sb);
 int __put_super_and_need_restart(struct super_block *sb);
 void unnamed_dev_init(void);
 
 /* 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 int may_umount_tree(struct vfsmount *);
 extern int may_umount(struct vfsmount *);
 extern void umount_tree(struct vfsmount *, int, struct list_head *);
 extern void release_mounts(struct list_head *);
 extern long do_mount(char *, char *, char *, unsigned long, void *);
 extern struct vfsmount *copy_tree(struct vfsmount *, struct dentry *, int);
 extern void mnt_set_mountpoint(struct vfsmount *, struct dentry *,
                                   struct vfsmount *);
 extern struct vfsmount *collect_mounts(struct vfsmount *, struct dentry *);
 extern void drop_collected_mounts(struct vfsmount *);
 
 extern int vfs_statfs(struct dentry *, struct kstatfs *);
 
 /* /sys/fs */
 extern struct kobject *fs_kobj;
 
 #define FLOCK_VERIFY_READ  1
 #define FLOCK_VERIFY_WRITE 2
 
 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;
 }
 
 extern int rw_verify_area(int, struct file *, loff_t *, size_t);
 
 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;
 }
 
 /* fs/open.c */
 
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
                        struct file *filp);
 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 * dentry_open(struct dentry *, struct vfsmount *, int);
 extern int filp_close(struct file *, fl_owner_t id);
 extern char * getname(const char __user *);
 
 /* 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()     kmem_cache_alloc(names_cachep, 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 void bd_set_size(struct block_device *, loff_t size);
 extern void bd_forget(struct inode *inode);
 extern void bdput(struct block_device *);
 extern struct block_device *open_by_devnum(dev_t, unsigned);
 #else
 static inline void bd_forget(struct inode *inode) {}
 #endif
 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 inode *, struct file *, unsigned, unsigned long);
 extern int blkdev_driver_ioctl(struct inode *inode, struct file *file,
                                struct gendisk *disk, unsigned cmd,
                                unsigned long arg);
 extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
 extern int blkdev_get(struct block_device *, mode_t, unsigned);
 extern int blkdev_put(struct block_device *);
 extern int bd_claim(struct block_device *, void *);
 extern void bd_release(struct block_device *);
 #ifdef CONFIG_SYSFS
 extern int bd_claim_by_disk(struct block_device *, void *, struct gendisk *);
 extern void bd_release_from_disk(struct block_device *, struct gendisk *);
 #else
 #define bd_claim_by_disk(bdev, holder, disk)    bd_claim(bdev, holder)
 #define bd_release_from_disk(bdev, disk)        bd_release(bdev)
 #endif
 #endif
 
 /* fs/char_dev.c */
 #define CHRDEV_MAJOR_HASH_SIZE  255
 extern int alloc_chrdev_region(dev_t *, unsigned, unsigned, const char *);
 extern int register_chrdev_region(dev_t, unsigned, const char *);
 extern int register_chrdev(unsigned int, const char *,
                            const struct file_operations *);
 extern void unregister_chrdev(unsigned int, const char *);
 extern void unregister_chrdev_region(dev_t, unsigned);
 extern void chrdev_show(struct seq_file *,off_t);
 
 /* fs/block_dev.c */
 #define BDEVNAME_SIZE   32      /* Largest string for a blockdev identifier */
 
 #ifdef CONFIG_BLOCK
 #define BLKDEV_MAJOR_HASH_SIZE  255
 extern const char *__bdevname(dev_t, char *buffer);
 extern const char *bdevname(struct block_device *bdev, char *buffer);
 extern struct block_device *lookup_bdev(const char *);
 extern struct block_device *open_bdev_excl(const char *, int, void *);
 extern void close_bdev_excl(struct block_device *);
 extern void blkdev_show(struct seq_file *,off_t);
 #else
 #define BLKDEV_MAJOR_HASH_SIZE  0
 #endif
 
 extern void init_special_inode(struct inode *, umode_t, dev_t);
 
 /* Invalid inode operations -- fs/bad_inode.c */
 extern void make_bad_inode(struct inode *);
 extern int is_bad_inode(struct inode *);
 
 extern const struct file_operations read_fifo_fops;
 extern const struct file_operations write_fifo_fops;
 extern const struct file_operations rdwr_fifo_fops;
 
 extern int fs_may_remount_ro(struct super_block *);
 
 #ifdef CONFIG_BLOCK
 /*
  * return READ, READA, or WRITE
  */
 #define bio_rw(bio)             ((bio)->bi_rw & (RW_MASK | RWA_MASK))
 
 /*
  * return data direction, READ or WRITE
  */
 #define bio_data_dir(bio)       ((bio)->bi_rw & 1)
 
 extern int check_disk_change(struct block_device *);
 extern int __invalidate_device(struct block_device *);
 extern int invalidate_partition(struct gendisk *, int);
 #endif
 extern int invalidate_inodes(struct super_block *);
 unsigned long __invalidate_mapping_pages(struct address_space *mapping,
                                         pgoff_t start, pgoff_t end,
                                         bool be_atomic);
 unsigned long invalidate_mapping_pages(struct address_space *mapping,
                                         pgoff_t start, pgoff_t end);
 
 static inline unsigned long __deprecated
 invalidate_inode_pages(struct address_space *mapping)
 {
         return invalidate_mapping_pages(mapping, 0, ~0UL);
 }
 
 static inline void invalidate_remote_inode(struct inode *inode)
 {
         if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
             S_ISLNK(inode->i_mode))
                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
 }
 extern int invalidate_inode_pages2(struct address_space *mapping);
 extern int invalidate_inode_pages2_range(struct address_space *mapping,
                                          pgoff_t start, pgoff_t end);
 extern int write_inode_now(struct inode *, int);
 extern int filemap_fdatawrite(struct address_space *);
 extern int filemap_flush(struct address_space *);
 extern int filemap_fdatawait(struct address_space *);
 extern int filemap_write_and_wait(struct address_space *mapping);
 extern int filemap_write_and_wait_range(struct address_space *mapping,
                                         loff_t lstart, loff_t lend);
 extern int wait_on_page_writeback_range(struct address_space *mapping,
                                 pgoff_t start, pgoff_t end);
 extern int __filemap_fdatawrite_range(struct address_space *mapping,
                                 loff_t start, loff_t end, int sync_mode);
 
 extern long do_fsync(struct file *file, int datasync);
 extern void sync_supers(void);
 extern void sync_filesystems(int wait);
 extern void __fsync_super(struct super_block *sb);
 extern void emergency_sync(void);
 extern void emergency_remount(void);
 extern int do_remount_sb(struct super_block *sb, int flags,
                          void *data, int force);
 #ifdef CONFIG_BLOCK
 extern sector_t bmap(struct inode *, sector_t);
 #endif
 extern int notify_change(struct dentry *, struct iattr *);
 extern int permission(struct inode *, int, struct nameidata *);
 extern int generic_permission(struct inode *, int,
                 int (*check_acl)(struct inode *, int));
 
 extern int get_write_access(struct inode *);
 extern int deny_write_access(struct file *);
 static inline void put_write_access(struct inode * inode)
 {
         atomic_dec(&inode->i_writecount);
 }
 static inline void allow_write_access(struct file *file)
 {
         if (file)
                 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
 }
 extern int do_pipe(int *);
 extern struct file *create_read_pipe(struct file *f);
 extern struct file *create_write_pipe(void);
 extern void free_write_pipe(struct file *);
 
 extern int open_namei(int dfd, const char *, int, int, struct nameidata *);
 extern int may_open(struct nameidata *, int, int);
 
 extern int kernel_read(struct file *, unsigned long, char *, unsigned long);
 extern struct file * open_exec(const char *);
  
 /* fs/dcache.c -- generic fs support functions */
 extern int is_subdir(struct dentry *, struct dentry *);
 extern ino_t find_inode_number(struct dentry *, struct qstr *);
 
 #include <linux/err.h>
 
 /* needed for stackable file system support */
 extern loff_t default_llseek(struct file *file, loff_t offset, int origin);
 
 extern loff_t vfs_llseek(struct file *file, loff_t offset, int origin);
 
 extern void inode_init_once(struct inode *);
 extern void iput(struct inode *);
 extern struct inode * igrab(struct inode *);
 extern ino_t iunique(struct super_block *, ino_t);
 extern int inode_needs_sync(struct inode *inode);
 extern void generic_delete_inode(struct inode *inode);
 extern void generic_drop_inode(struct inode *inode);
 
 extern struct inode *ilookup5_nowait(struct super_block *sb,
                 unsigned long hashval, int (*test)(struct inode *, void *),
                 void *data);
 extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
                 int (*test)(struct inode *, void *), void *data);
 extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
 
 extern struct inode * iget5_locked(struct super_block *, unsigned long, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
 extern struct inode * iget_locked(struct super_block *, unsigned long);
 extern void unlock_new_inode(struct inode *);
 
 extern void __iget(struct inode * inode);
 extern void iget_failed(struct inode *);
 extern void clear_inode(struct inode *);
 extern void destroy_inode(struct inode *);
 extern struct inode *new_inode(struct super_block *);
 extern int __remove_suid(struct dentry *, int);
 extern int should_remove_suid(struct dentry *);
 extern int remove_suid(struct dentry *);
 
 extern void __insert_inode_hash(struct inode *, unsigned long hashval);
 extern void remove_inode_hash(struct inode *);
 static inline void insert_inode_hash(struct inode *inode) {
         __insert_inode_hash(inode, inode->i_ino);
 }
 
 extern struct file * get_empty_filp(void);
 extern void file_move(struct file *f, struct percpu_list *list);
 extern void file_kill(struct file *f);
 #ifdef CONFIG_BLOCK
 struct bio;
 extern void submit_bio(int, struct bio *);
 extern int bdev_read_only(struct block_device *);
 #endif
 extern int set_blocksize(struct block_device *, int);
 extern int sb_set_blocksize(struct super_block *, int);
 extern int sb_min_blocksize(struct super_block *, int);
 extern int sb_has_dirty_inodes(struct super_block *);
 
 extern int generic_file_mmap(struct file *, struct vm_area_struct *);
 extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
 extern int file_read_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size);
 int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk);
 extern ssize_t generic_file_aio_read(struct kiocb *, const struct iovec *, unsigned long, loff_t);
 extern ssize_t generic_file_aio_write(struct kiocb *, const struct iovec *, unsigned long, loff_t);
 extern ssize_t generic_file_aio_write_nolock(struct kiocb *, const struct iovec *,
                 unsigned long, loff_t);
 extern ssize_t generic_file_direct_write(struct kiocb *, const struct iovec *,
                 unsigned long *, loff_t, loff_t *, size_t, size_t);
 extern ssize_t generic_file_buffered_write(struct kiocb *, const struct iovec *,
                 unsigned long, loff_t, loff_t *, size_t, ssize_t);
 extern ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos);
 extern ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos);
 extern int generic_segment_checks(const struct iovec *iov,
                 unsigned long *nr_segs, size_t *count, int access_flags);
 
 /* fs/splice.c */
 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
                 struct pipe_inode_info *, size_t, unsigned int);
 extern ssize_t generic_file_splice_write(struct pipe_inode_info *,
                 struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_file_splice_write_nolock(struct pipe_inode_info *,
                 struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,
                 struct file *out, loff_t *, size_t len, unsigned int flags);
 extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
                 size_t len, unsigned int flags);
 
 extern void
 file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping);
 extern loff_t no_llseek(struct file *file, loff_t offset, int origin);
 extern loff_t generic_file_llseek(struct file *file, loff_t offset, int origin);
 extern loff_t remote_llseek(struct file *file, loff_t offset, int origin);
 extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);
 
 #ifdef CONFIG_FS_XIP
 extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
                              loff_t *ppos);
 extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
 extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
                               size_t len, loff_t *ppos);
 extern int xip_truncate_page(struct address_space *mapping, loff_t from);
 #else
 static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
 {
         return 0;
 }
 #endif
 
 #ifdef CONFIG_BLOCK
 ssize_t __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
         struct block_device *bdev, const struct iovec *iov, loff_t offset,
         unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
         int lock_type);
 
 enum {
         DIO_LOCKING = 1, /* need locking between buffered and direct access */
         DIO_NO_LOCKING,  /* bdev; no locking at all between buffered/direct */
         DIO_OWN_LOCKING, /* filesystem locks buffered and direct internally */
 };
 
 static inline ssize_t blockdev_direct_IO(int rw, struct kiocb *iocb,
         struct inode *inode, struct block_device *bdev, const struct iovec *iov,
         loff_t offset, unsigned long nr_segs, get_block_t get_block,
         dio_iodone_t end_io)
 {
         return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
                                 nr_segs, get_block, end_io, DIO_LOCKING);
 }
 
 static inline ssize_t blockdev_direct_IO_no_locking(int rw, struct kiocb *iocb,
         struct inode *inode, struct block_device *bdev, const struct iovec *iov,
         loff_t offset, unsigned long nr_segs, get_block_t get_block,
         dio_iodone_t end_io)
 {
         return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
                                 nr_segs, get_block, end_io, DIO_NO_LOCKING);
 }
 
 static inline ssize_t blockdev_direct_IO_own_locking(int rw, struct kiocb *iocb,
         struct inode *inode, struct block_device *bdev, const struct iovec *iov,
         loff_t offset, unsigned long nr_segs, get_block_t get_block,
         dio_iodone_t end_io)
 {
         return __blockdev_direct_IO(rw, iocb, inode, bdev, iov, offset,
                                 nr_segs, get_block, end_io, DIO_OWN_LOCKING);
 }
 #endif
 
 extern const struct file_operations generic_ro_fops;
 
 #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))
 
 extern int vfs_readlink(struct dentry *, char __user *, int, const char *);
 extern int vfs_follow_link(struct nameidata *, const char *);
 extern int page_readlink(struct dentry *, char __user *, int);
 extern void *page_follow_link_light(struct dentry *, struct nameidata *);
 extern void page_put_link(struct dentry *, struct nameidata *, void *);
 extern int __page_symlink(struct inode *inode, const char *symname, int len,
                 gfp_t gfp_mask);
 extern int page_symlink(struct inode *inode, const char *symname, int len);
 extern const struct inode_operations page_symlink_inode_operations;
 extern int generic_readlink(struct dentry *, char __user *, int);
 extern void generic_fillattr(struct inode *, struct kstat *);
 extern int vfs_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 void inode_add_bytes(struct inode *inode, loff_t bytes);
 void inode_sub_bytes(struct inode *inode, loff_t bytes);
 loff_t inode_get_bytes(struct inode *inode);
 void inode_set_bytes(struct inode *inode, loff_t bytes);
 
 extern int vfs_readdir(struct file *, filldir_t, void *);
 
 extern int vfs_stat(char __user *, struct kstat *);
 extern int vfs_lstat(char __user *, struct kstat *);
 extern int vfs_stat_fd(int dfd, char __user *, struct kstat *);
 extern int vfs_lstat_fd(int dfd, char __user *, struct kstat *);
 extern int vfs_fstat(unsigned int, struct kstat *);
 
 extern long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
                     unsigned long arg);
 
 extern void get_filesystem(struct file_system_type *fs);
 extern void put_filesystem(struct file_system_type *fs);
 extern struct file_system_type *get_fs_type(const char *name);
 extern struct super_block *get_super(struct block_device *);
 extern struct super_block *user_get_super(dev_t);
 extern void drop_super(struct super_block *sb);
 
 extern int dcache_dir_open(struct inode *, struct file *);
 extern int dcache_dir_close(struct inode *, struct file *);
 extern loff_t dcache_dir_lseek(struct file *, loff_t, int);
 extern int dcache_readdir(struct file *, void *, filldir_t);
 extern int simple_getattr(struct vfsmount *, struct dentry *, struct kstat *);
 extern int simple_statfs(struct dentry *, struct kstatfs *);
 extern int simple_link(struct dentry *, struct inode *, struct dentry *);
 extern int simple_unlink(struct inode *, struct dentry *);
 extern int simple_rmdir(struct inode *, struct dentry *);
 extern int simple_rename(struct inode *, struct dentry *, struct inode *, struct dentry *);
 extern int simple_sync_file(struct file *, struct dentry *, int);
 extern int simple_empty(struct dentry *);
 extern int simple_readpage(struct file *file, struct page *page);
 extern int simple_prepare_write(struct file *file, struct page *page,
                         unsigned offset, unsigned to);
 extern int simple_write_begin(struct file *file, struct address_space *mapping,
                         loff_t pos, unsigned len, unsigned flags,
                         struct page **pagep, void **fsdata);
 extern int simple_write_end(struct file *file, struct address_space *mapping,
                         loff_t pos, unsigned len, unsigned copied,
                         struct page *page, void *fsdata);
 
 extern struct dentry *simple_lookup(struct inode *, struct dentry *, struct nameidata *);
 extern ssize_t generic_read_dir(struct file *, char __user *, size_t, loff_t *);
 extern const struct file_operations simple_dir_operations;
 extern const struct inode_operations simple_dir_inode_operations;
 struct tree_descr { char *name; const struct file_operations *ops; int mode; };
 struct dentry *d_alloc_name(struct dentry *, const char *);
 extern int simple_fill_super(struct super_block *, int, struct tree_descr *);
 extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
 extern void simple_release_fs(struct vfsmount **mount, int *count);
 
 extern ssize_t simple_read_from_buffer(void __user *, size_t, loff_t *, const void *, size_t);
 
 #ifdef CONFIG_MIGRATION
 extern int buffer_migrate_page(struct address_space *,
                                 struct page *, struct page *);
 #else
 #define buffer_migrate_page NULL
 #endif
 
 extern int inode_change_ok(struct inode *, struct iattr *);
 extern int __must_check inode_setattr(struct inode *, struct iattr *);
 
 extern void file_update_time(struct file *file);
 
 extern int generic_show_options(struct seq_file *m, struct vfsmount *mnt);
 extern void save_mount_options(struct super_block *sb, char *options);
 
 static inline ino_t parent_ino(struct dentry *dentry)
 {
         ino_t res;
 
         spin_lock(&dentry->d_lock);
         res = dentry->d_parent->d_inode->i_ino;
         spin_unlock(&dentry->d_lock);
         return res;
 }
 
 /* kernel/fork.c */
 extern int unshare_files(void);
 
 /* Transaction based IO helpers */
 
 /*
  * An argresp is stored in an allocated page and holds the
  * size of the argument or response, along with its content
  */
 struct simple_transaction_argresp {
         ssize_t size;
         char data[0];
 };
 
 #define SIMPLE_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct simple_transaction_argresp))
 
 char *simple_transaction_get(struct file *file, const char __user *buf,
                                 size_t size);
 ssize_t simple_transaction_read(struct file *file, char __user *buf,
                                 size_t size, loff_t *pos);
 int simple_transaction_release(struct inode *inode, struct file *file);
 
 static inline void simple_transaction_set(struct file *file, size_t n)
 {
         struct simple_transaction_argresp *ar = file->private_data;
 
         BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
 
         /*
          * The barrier ensures that ar->size will really remain zero until
          * ar->data is ready for reading.
          */
         smp_mb();
         ar->size = n;
 }
 
 /*
  * simple attribute files
  *
  * These attributes behave similar to those in sysfs:
  *
  * Writing to an attribute immediately sets a value, an open file can be
  * written to multiple times.
  *
  * Reading from an attribute creates a buffer from the value that might get
  * read with multiple read calls. When the attribute has been read
  * completely, no further read calls are possible until the file is opened
  * again.
  *
  * All attributes contain a text representation of a numeric value
  * that are accessed with the get() and set() functions.
  */
 #define DEFINE_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)            \
 static int __fops ## _open(struct inode *inode, struct file *file)      \
 {                                                                       \
         __simple_attr_check_format(__fmt, 0ull);                        \
         return simple_attr_open(inode, file, __get, __set, __fmt);      \
 }                                                                       \
 static struct file_operations __fops = {                                \
         .owner   = THIS_MODULE,                                         \
         .open    = __fops ## _open,                                     \
         .release = simple_attr_release,                                 \
         .read    = simple_attr_read,                                    \
         .write   = simple_attr_write,                                   \
 };
 
 static inline void __attribute__((format(printf, 1, 2)))
 __simple_attr_check_format(const char *fmt, ...)
 {
         /* don't do anything, just let the compiler check the arguments; */
 }
 
 int simple_attr_open(struct inode *inode, struct file *file,
                      int (*get)(void *, u64 *), int (*set)(void *, u64),
                      const char *fmt);
 int simple_attr_release(struct inode *inode, struct file *file);
 ssize_t simple_attr_read(struct file *file, char __user *buf,
                          size_t len, loff_t *ppos);
 ssize_t simple_attr_write(struct file *file, const char __user *buf,
                           size_t len, loff_t *ppos);
 
 
 #ifdef CONFIG_SECURITY
 static inline char *alloc_secdata(void)
 {
         return (char *)get_zeroed_page(GFP_KERNEL);
 }
 
 static inline void free_secdata(void *secdata)
 {
         free_page((unsigned long)secdata);
 }
 #else
 static inline char *alloc_secdata(void)
 {
         return (char *)1;
 }
 
 static inline void free_secdata(void *secdata)
 { }
 #endif  /* CONFIG_SECURITY */
 
 struct ctl_table;
 int proc_nr_files(struct ctl_table *table, int write, struct file *filp,
                   void __user *buffer, size_t *lenp, loff_t *ppos);
 
 int get_filesystem_list(char * buf);
 
 #endif /* __KERNEL__ */
 #endif /* _LINUX_FS_H */