/* SPDX-License-Identifier: GPL-2.0 */

  /*

   *  ext4.h

   *
   * Copyright (C) 1992, 1993, 1994, 1995
   * Remy Card (card@masi.ibp.fr)
   * Laboratoire MASI - Institut Blaise Pascal
   * Universite Pierre et Marie Curie (Paris VI)
   *
   *  from
   *
   *  linux/include/linux/minix_fs.h
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   */

  #ifndef _EXT4_H
  #define _EXT4_H

  
  #include <linux/types.h>

  #include <linux/blkdev.h>

  #include <linux/magic.h>

  #include <linux/jbd2.h>

  #include <linux/quota.h>

  #include <linux/rwsem.h>
  #include <linux/rbtree.h>
  #include <linux/seqlock.h>
  #include <linux/mutex.h>

  #include <linux/timer.h>

  #include <linux/version.h>

  #include <linux/wait.h>

  #include <linux/sched/signal.h>

  #include <linux/blockgroup_lock.h>
  #include <linux/percpu_counter.h>

  #include <linux/ratelimit.h>

  #include <crypto/hash.h>

  #ifdef CONFIG_EXT4_FS_ENCRYPTION
  #include <linux/fscrypt_supp.h>
  #else
  #include <linux/fscrypt_notsupp.h>
  #endif

  #include <linux/falloc.h>

  #include <linux/percpu-rwsem.h>

  #ifdef __KERNEL__
  #include <linux/compat.h>
  #endif

  /*

   * The fourth extended filesystem constants/structures

   */
  
  /*

   * with AGGRESSIVE_CHECK allocator runs consistency checks over
   * structures. these checks slow things down a lot
   */
  #define AGGRESSIVE_CHECK__
  
  /*
   * with DOUBLE_CHECK defined mballoc creates persistent in-core
   * bitmaps, maintains and uses them to check for double allocations
   */
  #define DOUBLE_CHECK__
  
  /*

   * Define EXT4FS_DEBUG to produce debug messages

   */

  #undef EXT4FS_DEBUG

  
  /*

   * Debug code
   */

  #ifdef EXT4FS_DEBUG
  #define ext4_debug(f, a...)						\

  	do {								\

  		printk(KERN_DEBUG "EXT4-fs DEBUG (%s, %d): %s:",	\

  			__FILE__, __LINE__, __func__);			\

  		printk(KERN_DEBUG f, ## a);				\

  	} while (0)
  #else

  #define ext4_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)

  #endif

  /*
   * Turn on EXT_DEBUG to get lots of info about extents operations.
   */
  #define EXT_DEBUG__
  #ifdef EXT_DEBUG
  #define ext_debug(fmt, ...)	printk(fmt, ##__VA_ARGS__)
  #else
  #define ext_debug(fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
  #endif

  /* data type for block offset of block group */
  typedef int ext4_grpblk_t;
  
  /* data type for filesystem-wide blocks number */
  typedef unsigned long long ext4_fsblk_t;
  
  /* data type for file logical block number */
  typedef __u32 ext4_lblk_t;
  
  /* data type for block group number */
  typedef unsigned int ext4_group_t;

  enum SHIFT_DIRECTION {
  	SHIFT_LEFT = 0,
  	SHIFT_RIGHT,
  };

  /*

   * Flags used in mballoc's allocation_context flags field.

   *
   * Also used to show what's going on for debugging purposes when the
   * flag field is exported via the traceport interface
   */

  /* prefer goal again. length */

  #define EXT4_MB_HINT_MERGE		0x0001

  /* blocks already reserved */

  #define EXT4_MB_HINT_RESERVED		0x0002

  /* metadata is being allocated */

  #define EXT4_MB_HINT_METADATA		0x0004

  /* first blocks in the file */

  #define EXT4_MB_HINT_FIRST		0x0008

  /* search for the best chunk */

  #define EXT4_MB_HINT_BEST		0x0010

  /* data is being allocated */

  #define EXT4_MB_HINT_DATA		0x0020

  /* don't preallocate (for tails) */

  #define EXT4_MB_HINT_NOPREALLOC		0x0040

  /* allocate for locality group */

  #define EXT4_MB_HINT_GROUP_ALLOC	0x0080

  /* allocate goal blocks or none */

  #define EXT4_MB_HINT_GOAL_ONLY		0x0100

  /* goal is meaningful */

  #define EXT4_MB_HINT_TRY_GOAL		0x0200

  /* blocks already pre-reserved by delayed allocation */

  #define EXT4_MB_DELALLOC_RESERVED	0x0400

  /* We are doing stream allocation */
  #define EXT4_MB_STREAM_ALLOC		0x0800

  /* Use reserved root blocks if needed */
  #define EXT4_MB_USE_ROOT_BLOCKS		0x1000

  /* Use blocks from reserved pool */
  #define EXT4_MB_USE_RESERVED		0x2000

  
  struct ext4_allocation_request {
  	/* target inode for block we're allocating */
  	struct inode *inode;

  	/* how many blocks we want to allocate */
  	unsigned int len;

  	/* logical block in target inode */
  	ext4_lblk_t logical;

  	/* the closest logical allocated block to the left */
  	ext4_lblk_t lleft;

  	/* the closest logical allocated block to the right */
  	ext4_lblk_t lright;

  	/* phys. target (a hint) */
  	ext4_fsblk_t goal;
  	/* phys. block for the closest logical allocated block to the left */
  	ext4_fsblk_t pleft;
  	/* phys. block for the closest logical allocated block to the right */

  	ext4_fsblk_t pright;

  	/* flags. see above EXT4_MB_HINT_* */

  	unsigned int flags;

  };

  /*

   * Logical to physical block mapping, used by ext4_map_blocks()
   *
   * This structure is used to pass requests into ext4_map_blocks() as
   * well as to store the information returned by ext4_map_blocks().  It
   * takes less room on the stack than a struct buffer_head.
   */
  #define EXT4_MAP_NEW		(1 << BH_New)
  #define EXT4_MAP_MAPPED		(1 << BH_Mapped)
  #define EXT4_MAP_UNWRITTEN	(1 << BH_Unwritten)
  #define EXT4_MAP_BOUNDARY	(1 << BH_Boundary)

  #define EXT4_MAP_FLAGS		(EXT4_MAP_NEW | EXT4_MAP_MAPPED |\

  				 EXT4_MAP_UNWRITTEN | EXT4_MAP_BOUNDARY)

  
  struct ext4_map_blocks {
  	ext4_fsblk_t m_pblk;
  	ext4_lblk_t m_lblk;
  	unsigned int m_len;
  	unsigned int m_flags;
  };
  
  /*

   * Flags for ext4_io_end->flags
   */
  #define	EXT4_IO_END_UNWRITTEN	0x0001

  /*

   * For converting unwritten extents on a work queue. 'handle' is used for

   * buffered writeback.

   */

  typedef struct ext4_io_end {

  	struct list_head	list;		/* per-file finished IO list */

  	handle_t		*handle;	/* handle reserved for extent
  						 * conversion */

  	struct inode		*inode;		/* file being written to */

  	struct bio		*bio;		/* Linked list of completed
  						 * bios covering the extent */

  	unsigned int		flag;		/* unwritten or not */

  	atomic_t		count;		/* reference counter */

  	loff_t			offset;		/* offset in the file */
  	ssize_t			size;		/* size of the extent */

  } ext4_io_end_t;

  struct ext4_io_submit {

  	struct writeback_control *io_wbc;

  	struct bio		*io_bio;
  	ext4_io_end_t		*io_end;

  	sector_t		io_next_block;
  };

  /*

   * Special inodes numbers
   */

  #define	EXT4_BAD_INO		 1	/* Bad blocks inode */
  #define EXT4_ROOT_INO		 2	/* Root inode */

  #define EXT4_USR_QUOTA_INO	 3	/* User quota inode */
  #define EXT4_GRP_QUOTA_INO	 4	/* Group quota inode */

  #define EXT4_BOOT_LOADER_INO	 5	/* Boot loader inode */
  #define EXT4_UNDEL_DIR_INO	 6	/* Undelete directory inode */
  #define EXT4_RESIZE_INO		 7	/* Reserved group descriptors inode */
  #define EXT4_JOURNAL_INO	 8	/* Journal inode */

  /* First non-reserved inode for old ext4 filesystems */
  #define EXT4_GOOD_OLD_FIRST_INO	11

  
  /*
   * Maximal count of links to a file
   */

  #define EXT4_LINK_MAX		65000

  
  /*
   * Macro-instructions used to manage several block sizes
   */

  #define EXT4_MIN_BLOCK_SIZE		1024

  #define	EXT4_MAX_BLOCK_SIZE		65536
  #define EXT4_MIN_BLOCK_LOG_SIZE		10

  #define EXT4_MAX_BLOCK_LOG_SIZE		16

  #define EXT4_MAX_CLUSTER_LOG_SIZE	30

  #ifdef __KERNEL__

  # define EXT4_BLOCK_SIZE(s)		((s)->s_blocksize)

  #else

  # define EXT4_BLOCK_SIZE(s)		(EXT4_MIN_BLOCK_SIZE << (s)->s_log_block_size)

  #endif

  #define	EXT4_ADDR_PER_BLOCK(s)		(EXT4_BLOCK_SIZE(s) / sizeof(__u32))

  #define EXT4_CLUSTER_SIZE(s)		(EXT4_BLOCK_SIZE(s) << \
  					 EXT4_SB(s)->s_cluster_bits)

  #ifdef __KERNEL__

  # define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)

  # define EXT4_CLUSTER_BITS(s)		(EXT4_SB(s)->s_cluster_bits)

  #else

  # define EXT4_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)

  #endif
  #ifdef __KERNEL__

  #define	EXT4_ADDR_PER_BLOCK_BITS(s)	(EXT4_SB(s)->s_addr_per_block_bits)
  #define EXT4_INODE_SIZE(s)		(EXT4_SB(s)->s_inode_size)
  #define EXT4_FIRST_INO(s)		(EXT4_SB(s)->s_first_ino)

  #else

  #define EXT4_INODE_SIZE(s)	(((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
  				 EXT4_GOOD_OLD_INODE_SIZE : \

  				 (s)->s_inode_size)

  #define EXT4_FIRST_INO(s)	(((s)->s_rev_level == EXT4_GOOD_OLD_REV) ? \
  				 EXT4_GOOD_OLD_FIRST_INO : \

  				 (s)->s_first_ino)
  #endif

  #define EXT4_BLOCK_ALIGN(size, blkbits)		ALIGN((size), (1 << (blkbits)))

  #define EXT4_MAX_BLOCKS(size, offset, blkbits) \
  	((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
  								  blkbits))

  /* Translate a block number to a cluster number */
  #define EXT4_B2C(sbi, blk)	((blk) >> (sbi)->s_cluster_bits)
  /* Translate a cluster number to a block number */
  #define EXT4_C2B(sbi, cluster)	((cluster) << (sbi)->s_cluster_bits)
  /* Translate # of blks to # of clusters */
  #define EXT4_NUM_B2C(sbi, blks)	(((blks) + (sbi)->s_cluster_ratio - 1) >> \
  				 (sbi)->s_cluster_bits)

  /* Mask out the low bits to get the starting block of the cluster */
  #define EXT4_PBLK_CMASK(s, pblk) ((pblk) &				\
  				  ~((ext4_fsblk_t) (s)->s_cluster_ratio - 1))
  #define EXT4_LBLK_CMASK(s, lblk) ((lblk) &				\
  				  ~((ext4_lblk_t) (s)->s_cluster_ratio - 1))
  /* Get the cluster offset */
  #define EXT4_PBLK_COFF(s, pblk) ((pblk) &				\
  				 ((ext4_fsblk_t) (s)->s_cluster_ratio - 1))
  #define EXT4_LBLK_COFF(s, lblk) ((lblk) &				\
  				 ((ext4_lblk_t) (s)->s_cluster_ratio - 1))

  /*

   * Structure of a blocks group descriptor
   */

  struct ext4_group_desc

  {

  	__le32	bg_block_bitmap_lo;	/* Blocks bitmap block */

  	__le32	bg_inode_bitmap_lo;	/* Inodes bitmap block */
  	__le32	bg_inode_table_lo;	/* Inodes table block */

  	__le16	bg_free_blocks_count_lo;/* Free blocks count */
  	__le16	bg_free_inodes_count_lo;/* Free inodes count */
  	__le16	bg_used_dirs_count_lo;	/* Directories count */

  	__le16	bg_flags;		/* EXT4_BG_flags (INODE_UNINIT, etc) */

  	__le32  bg_exclude_bitmap_lo;   /* Exclude bitmap for snapshots */
  	__le16  bg_block_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+bbitmap) LE */
  	__le16  bg_inode_bitmap_csum_lo;/* crc32c(s_uuid+grp_num+ibitmap) LE */

  	__le16  bg_itable_unused_lo;	/* Unused inodes count */

  	__le16  bg_checksum;		/* crc16(sb_uuid+group+desc) */

  	__le32	bg_block_bitmap_hi;	/* Blocks bitmap block MSB */
  	__le32	bg_inode_bitmap_hi;	/* Inodes bitmap block MSB */
  	__le32	bg_inode_table_hi;	/* Inodes table block MSB */

  	__le16	bg_free_blocks_count_hi;/* Free blocks count MSB */
  	__le16	bg_free_inodes_count_hi;/* Free inodes count MSB */
  	__le16	bg_used_dirs_count_hi;	/* Directories count MSB */

  	__le16  bg_itable_unused_hi;    /* Unused inodes count MSB */

  	__le32  bg_exclude_bitmap_hi;   /* Exclude bitmap block MSB */
  	__le16  bg_block_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+bbitmap) BE */
  	__le16  bg_inode_bitmap_csum_hi;/* crc32c(s_uuid+grp_num+ibitmap) BE */
  	__u32   bg_reserved;

  };

  #define EXT4_BG_INODE_BITMAP_CSUM_HI_END	\
  	(offsetof(struct ext4_group_desc, bg_inode_bitmap_csum_hi) + \
  	 sizeof(__le16))
  #define EXT4_BG_BLOCK_BITMAP_CSUM_HI_END	\
  	(offsetof(struct ext4_group_desc, bg_block_bitmap_csum_hi) + \
  	 sizeof(__le16))

  /*
   * Structure of a flex block group info
   */
  
  struct flex_groups {

  	atomic64_t	free_clusters;
  	atomic_t	free_inodes;
  	atomic_t	used_dirs;

  };

  #define EXT4_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not in use */
  #define EXT4_BG_BLOCK_UNINIT	0x0002 /* Block bitmap not in use */
  #define EXT4_BG_INODE_ZEROED	0x0004 /* On-disk itable initialized to zero */

  /*
   * Macro-instructions used to manage group descriptors
   */

  #define EXT4_MIN_DESC_SIZE		32

  #define EXT4_MIN_DESC_SIZE_64BIT	64

  #define	EXT4_MAX_DESC_SIZE		EXT4_MIN_BLOCK_SIZE
  #define EXT4_DESC_SIZE(s)		(EXT4_SB(s)->s_desc_size)

  #ifdef __KERNEL__

  # define EXT4_BLOCKS_PER_GROUP(s)	(EXT4_SB(s)->s_blocks_per_group)

  # define EXT4_CLUSTERS_PER_GROUP(s)	(EXT4_SB(s)->s_clusters_per_group)

  # define EXT4_DESC_PER_BLOCK(s)		(EXT4_SB(s)->s_desc_per_block)
  # define EXT4_INODES_PER_GROUP(s)	(EXT4_SB(s)->s_inodes_per_group)
  # define EXT4_DESC_PER_BLOCK_BITS(s)	(EXT4_SB(s)->s_desc_per_block_bits)

  #else

  # define EXT4_BLOCKS_PER_GROUP(s)	((s)->s_blocks_per_group)

  # define EXT4_DESC_PER_BLOCK(s)		(EXT4_BLOCK_SIZE(s) / EXT4_DESC_SIZE(s))

  # define EXT4_INODES_PER_GROUP(s)	((s)->s_inodes_per_group)

  #endif
  
  /*
   * Constants relative to the data blocks
   */

  #define	EXT4_NDIR_BLOCKS		12
  #define	EXT4_IND_BLOCK			EXT4_NDIR_BLOCKS
  #define	EXT4_DIND_BLOCK			(EXT4_IND_BLOCK + 1)
  #define	EXT4_TIND_BLOCK			(EXT4_DIND_BLOCK + 1)
  #define	EXT4_N_BLOCKS			(EXT4_TIND_BLOCK + 1)

  
  /*
   * Inode flags
   */

  #define	EXT4_SECRM_FL			0x00000001 /* Secure deletion */
  #define	EXT4_UNRM_FL			0x00000002 /* Undelete */
  #define	EXT4_COMPR_FL			0x00000004 /* Compress file */
  #define EXT4_SYNC_FL			0x00000008 /* Synchronous updates */
  #define EXT4_IMMUTABLE_FL		0x00000010 /* Immutable file */
  #define EXT4_APPEND_FL			0x00000020 /* writes to file may only append */
  #define EXT4_NODUMP_FL			0x00000040 /* do not dump file */
  #define EXT4_NOATIME_FL			0x00000080 /* do not update atime */

  /* Reserved for compression usage... */

  #define EXT4_DIRTY_FL			0x00000100
  #define EXT4_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
  #define EXT4_NOCOMPR_FL			0x00000400 /* Don't compress */

  	/* nb: was previously EXT2_ECOMPR_FL */
  #define EXT4_ENCRYPT_FL			0x00000800 /* encrypted file */

  /* End compression flags --- maybe not all used */

  #define EXT4_INDEX_FL			0x00001000 /* hash-indexed directory */
  #define EXT4_IMAGIC_FL			0x00002000 /* AFS directory */
  #define EXT4_JOURNAL_DATA_FL		0x00004000 /* file data should be journaled */
  #define EXT4_NOTAIL_FL			0x00008000 /* file tail should not be merged */
  #define EXT4_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
  #define EXT4_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/

  #define EXT4_HUGE_FILE_FL               0x00040000 /* Set to each huge file */

  #define EXT4_EXTENTS_FL			0x00080000 /* Inode uses extents */

  #define EXT4_EA_INODE_FL	        0x00200000 /* Inode used for large EA */

  #define EXT4_EOFBLOCKS_FL		0x00400000 /* Blocks allocated beyond EOF */

  #define EXT4_INLINE_DATA_FL		0x10000000 /* Inode has inline data. */

  #define EXT4_PROJINHERIT_FL		0x20000000 /* Create with parents projid */

  #define EXT4_RESERVED_FL		0x80000000 /* reserved for ext4 lib */

  #define EXT4_FL_USER_VISIBLE		0x304BDFFF /* User visible flags */

  #define EXT4_FL_USER_MODIFIABLE		0x204BC0FF /* User modifiable flags */

  /* Flags we can manipulate with through EXT4_IOC_FSSETXATTR */

  #define EXT4_FL_XFLAG_VISIBLE		(EXT4_SYNC_FL | \
  					 EXT4_IMMUTABLE_FL | \
  					 EXT4_APPEND_FL | \
  					 EXT4_NODUMP_FL | \
  					 EXT4_NOATIME_FL | \
  					 EXT4_PROJINHERIT_FL)

  /* Flags that should be inherited by new inodes from their parent. */
  #define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\

  			   EXT4_SYNC_FL | EXT4_NODUMP_FL | EXT4_NOATIME_FL |\

  			   EXT4_NOCOMPR_FL | EXT4_JOURNAL_DATA_FL |\

  			   EXT4_NOTAIL_FL | EXT4_DIRSYNC_FL |\
  			   EXT4_PROJINHERIT_FL)

  /* Flags that are appropriate for regular files (all but dir-specific ones). */
  #define EXT4_REG_FLMASK (~(EXT4_DIRSYNC_FL | EXT4_TOPDIR_FL))
  
  /* Flags that are appropriate for non-directories/regular files. */
  #define EXT4_OTHER_FLMASK (EXT4_NODUMP_FL | EXT4_NOATIME_FL)
  
  /* Mask out flags that are inappropriate for the given type of inode. */
  static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
  {
  	if (S_ISDIR(mode))
  		return flags;
  	else if (S_ISREG(mode))
  		return flags & EXT4_REG_FLMASK;
  	else
  		return flags & EXT4_OTHER_FLMASK;
  }

  /*
   * Inode flags used for atomic set/get
   */
  enum {
  	EXT4_INODE_SECRM	= 0,	/* Secure deletion */
  	EXT4_INODE_UNRM		= 1,	/* Undelete */
  	EXT4_INODE_COMPR	= 2,	/* Compress file */
  	EXT4_INODE_SYNC		= 3,	/* Synchronous updates */
  	EXT4_INODE_IMMUTABLE	= 4,	/* Immutable file */
  	EXT4_INODE_APPEND	= 5,	/* writes to file may only append */
  	EXT4_INODE_NODUMP	= 6,	/* do not dump file */
  	EXT4_INODE_NOATIME	= 7,	/* do not update atime */
  /* Reserved for compression usage... */
  	EXT4_INODE_DIRTY	= 8,
  	EXT4_INODE_COMPRBLK	= 9,	/* One or more compressed clusters */
  	EXT4_INODE_NOCOMPR	= 10,	/* Don't compress */

  	EXT4_INODE_ENCRYPT	= 11,	/* Encrypted file */

  /* End compression flags --- maybe not all used */
  	EXT4_INODE_INDEX	= 12,	/* hash-indexed directory */
  	EXT4_INODE_IMAGIC	= 13,	/* AFS directory */
  	EXT4_INODE_JOURNAL_DATA	= 14,	/* file data should be journaled */
  	EXT4_INODE_NOTAIL	= 15,	/* file tail should not be merged */
  	EXT4_INODE_DIRSYNC	= 16,	/* dirsync behaviour (directories only) */
  	EXT4_INODE_TOPDIR	= 17,	/* Top of directory hierarchies*/
  	EXT4_INODE_HUGE_FILE	= 18,	/* Set to each huge file */
  	EXT4_INODE_EXTENTS	= 19,	/* Inode uses extents */
  	EXT4_INODE_EA_INODE	= 21,	/* Inode used for large EA */
  	EXT4_INODE_EOFBLOCKS	= 22,	/* Blocks allocated beyond EOF */

  	EXT4_INODE_INLINE_DATA	= 28,	/* Data in inode. */

  	EXT4_INODE_PROJINHERIT	= 29,	/* Create with parents projid */

  	EXT4_INODE_RESERVED	= 31,	/* reserved for ext4 lib */
  };

  /*

   * Since it's pretty easy to mix up bit numbers and hex values, we use a
   * build-time check to make sure that EXT4_XXX_FL is consistent with respect to
   * EXT4_INODE_XXX. If all is well, the macros will be dropped, so, it won't cost
   * any extra space in the compiled kernel image, otherwise, the build will fail.
   * It's important that these values are the same, since we are using
   * EXT4_INODE_XXX to test for flag values, but EXT4_XXX_FL must be consistent
   * with the values of FS_XXX_FL defined in include/linux/fs.h and the on-disk
   * values found in ext2, ext3 and ext4 filesystems, and of course the values
   * defined in e2fsprogs.

   *
   * It's not paranoia if the Murphy's Law really *is* out to get you.  :-)
   */

  #define TEST_FLAG_VALUE(FLAG) (EXT4_##FLAG##_FL == (1 << EXT4_INODE_##FLAG))
  #define CHECK_FLAG_VALUE(FLAG) BUILD_BUG_ON(!TEST_FLAG_VALUE(FLAG))

  static inline void ext4_check_flag_values(void)
  {
  	CHECK_FLAG_VALUE(SECRM);
  	CHECK_FLAG_VALUE(UNRM);
  	CHECK_FLAG_VALUE(COMPR);
  	CHECK_FLAG_VALUE(SYNC);
  	CHECK_FLAG_VALUE(IMMUTABLE);
  	CHECK_FLAG_VALUE(APPEND);
  	CHECK_FLAG_VALUE(NODUMP);
  	CHECK_FLAG_VALUE(NOATIME);
  	CHECK_FLAG_VALUE(DIRTY);
  	CHECK_FLAG_VALUE(COMPRBLK);
  	CHECK_FLAG_VALUE(NOCOMPR);

  	CHECK_FLAG_VALUE(ENCRYPT);

  	CHECK_FLAG_VALUE(INDEX);
  	CHECK_FLAG_VALUE(IMAGIC);
  	CHECK_FLAG_VALUE(JOURNAL_DATA);
  	CHECK_FLAG_VALUE(NOTAIL);
  	CHECK_FLAG_VALUE(DIRSYNC);
  	CHECK_FLAG_VALUE(TOPDIR);
  	CHECK_FLAG_VALUE(HUGE_FILE);
  	CHECK_FLAG_VALUE(EXTENTS);
  	CHECK_FLAG_VALUE(EA_INODE);
  	CHECK_FLAG_VALUE(EOFBLOCKS);

  	CHECK_FLAG_VALUE(INLINE_DATA);

  	CHECK_FLAG_VALUE(PROJINHERIT);

  	CHECK_FLAG_VALUE(RESERVED);
  }

  /* Used to pass group descriptor data when online resize is done */

  struct ext4_new_group_input {

  	__u32 group;		/* Group number for this data */
  	__u64 block_bitmap;	/* Absolute block number of block bitmap */
  	__u64 inode_bitmap;	/* Absolute block number of inode bitmap */
  	__u64 inode_table;	/* Absolute block number of inode table start */
  	__u32 blocks_count;	/* Total number of blocks in this group */
  	__u16 reserved_blocks;	/* Number of reserved blocks in this group */

  	__u16 unused;
  };

  #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
  struct compat_ext4_new_group_input {
  	u32 group;
  	compat_u64 block_bitmap;
  	compat_u64 inode_bitmap;
  	compat_u64 inode_table;
  	u32 blocks_count;
  	u16 reserved_blocks;
  	u16 unused;
  };
  #endif

  /* The struct ext4_new_group_input in kernel space, with free_blocks_count */
  struct ext4_new_group_data {

  	__u32 group;

  	__u64 block_bitmap;
  	__u64 inode_bitmap;
  	__u64 inode_table;

  	__u32 blocks_count;
  	__u16 reserved_blocks;
  	__u16 unused;
  	__u32 free_blocks_count;
  };

  /* Indexes used to index group tables in ext4_new_group_data */
  enum {
  	BLOCK_BITMAP = 0,	/* block bitmap */
  	INODE_BITMAP,		/* inode bitmap */
  	INODE_TABLE,		/* inode tables */
  	GROUP_TABLE_COUNT,
  };

  /*

   * Flags used by ext4_map_blocks()

   */

  	/* Allocate any needed blocks and/or convert an unwritten

  	   extent to be an initialized ext4 */

  #define EXT4_GET_BLOCKS_CREATE			0x0001

  	/* Request the creation of an unwritten extent */
  #define EXT4_GET_BLOCKS_UNWRIT_EXT		0x0002
  #define EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT	(EXT4_GET_BLOCKS_UNWRIT_EXT|\

  						 EXT4_GET_BLOCKS_CREATE)

  	/* Caller is from the delayed allocation writeout path
  	 * finally doing the actual allocation of delayed blocks */

  #define EXT4_GET_BLOCKS_DELALLOC_RESERVE	0x0004

  	/* caller is from the direct IO path, request to creation of an

  	unwritten extents if not allocated, split the unwritten

  	extent if blocks has been preallocated already*/

  #define EXT4_GET_BLOCKS_PRE_IO			0x0008

  #define EXT4_GET_BLOCKS_CONVERT			0x0010

  #define EXT4_GET_BLOCKS_IO_CREATE_EXT		(EXT4_GET_BLOCKS_PRE_IO|\

  					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)

  	/* Convert extent to initialized after IO complete */
  #define EXT4_GET_BLOCKS_IO_CONVERT_EXT		(EXT4_GET_BLOCKS_CONVERT|\

  					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)

  	/* Eventual metadata allocation (due to growing extent tree)
  	 * should not fail, so try to use reserved blocks for that.*/
  #define EXT4_GET_BLOCKS_METADATA_NOFAIL		0x0020

  	/* Don't normalize allocation size (used for fallocate) */
  #define EXT4_GET_BLOCKS_NO_NORMALIZE		0x0040

  	/* Request will not result in inode size update (user for fallocate) */
  #define EXT4_GET_BLOCKS_KEEP_SIZE		0x0080

  	/* Convert written extents to unwritten */

  #define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN	0x0100

  	/* Write zeros to newly created written extents */
  #define EXT4_GET_BLOCKS_ZERO			0x0200
  #define EXT4_GET_BLOCKS_CREATE_ZERO		(EXT4_GET_BLOCKS_CREATE |\
  					EXT4_GET_BLOCKS_ZERO)

  	/* Caller will submit data before dropping transaction handle. This
  	 * allows jbd2 to avoid submitting data before commit. */
  #define EXT4_GET_BLOCKS_IO_SUBMIT		0x0400

  
  /*

   * The bit position of these flags must not overlap with any of the

   * EXT4_GET_BLOCKS_*.  They are used by ext4_find_extent(),

   * read_extent_tree_block(), ext4_split_extent_at(),

   * ext4_ext_insert_extent(), and ext4_ext_create_new_leaf().
   * EXT4_EX_NOCACHE is used to indicate that the we shouldn't be
   * caching the extents when reading from the extent tree while a
   * truncate or punch hole operation is in progress.

   */

  #define EXT4_EX_NOCACHE				0x40000000
  #define EXT4_EX_FORCE_CACHE			0x20000000

  
  /*

   * Flags used by ext4_free_blocks
   */
  #define EXT4_FREE_BLOCKS_METADATA	0x0001
  #define EXT4_FREE_BLOCKS_FORGET		0x0002

  #define EXT4_FREE_BLOCKS_VALIDATED	0x0004

  #define EXT4_FREE_BLOCKS_NO_QUOT_UPDATE	0x0008

  #define EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER	0x0010
  #define EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER	0x0020

  
  /*

   * ioctl commands
   */

  #define	EXT4_IOC_GETFLAGS		FS_IOC_GETFLAGS
  #define	EXT4_IOC_SETFLAGS		FS_IOC_SETFLAGS
  #define	EXT4_IOC_GETVERSION		_IOR('f', 3, long)
  #define	EXT4_IOC_SETVERSION		_IOW('f', 4, long)

  #define	EXT4_IOC_GETVERSION_OLD		FS_IOC_GETVERSION
  #define	EXT4_IOC_SETVERSION_OLD		FS_IOC_SETVERSION

  #define EXT4_IOC_GETRSVSZ		_IOR('f', 5, long)
  #define EXT4_IOC_SETRSVSZ		_IOW('f', 6, long)

  #define EXT4_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
  #define EXT4_IOC_GROUP_ADD		_IOW('f', 8, struct ext4_new_group_input)
  #define EXT4_IOC_MIGRATE		_IO('f', 9)

   /* note ioctl 10 reserved for an early version of the FIEMAP ioctl */

   /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */

  #define EXT4_IOC_ALLOC_DA_BLKS		_IO('f', 12)

  #define EXT4_IOC_MOVE_EXT		_IOWR('f', 15, struct move_extent)

  #define EXT4_IOC_RESIZE_FS		_IOW('f', 16, __u64)

  #define EXT4_IOC_SWAP_BOOT		_IO('f', 17)

  #define EXT4_IOC_PRECACHE_EXTENTS	_IO('f', 18)

  #define EXT4_IOC_SET_ENCRYPTION_POLICY	FS_IOC_SET_ENCRYPTION_POLICY
  #define EXT4_IOC_GET_ENCRYPTION_PWSALT	FS_IOC_GET_ENCRYPTION_PWSALT
  #define EXT4_IOC_GET_ENCRYPTION_POLICY	FS_IOC_GET_ENCRYPTION_POLICY

  #ifndef FS_IOC_FSGETXATTR
  /* Until the uapi changes get merged for project quota... */
  
  #define FS_IOC_FSGETXATTR		_IOR('X', 31, struct fsxattr)
  #define FS_IOC_FSSETXATTR		_IOW('X', 32, struct fsxattr)
  
  /*
   * Structure for FS_IOC_FSGETXATTR and FS_IOC_FSSETXATTR.
   */
  struct fsxattr {
  	__u32		fsx_xflags;	/* xflags field value (get/set) */
  	__u32		fsx_extsize;	/* extsize field value (get/set)*/
  	__u32		fsx_nextents;	/* nextents field value (get)	*/
  	__u32		fsx_projid;	/* project identifier (get/set) */
  	unsigned char	fsx_pad[12];
  };
  
  /*
   * Flags for the fsx_xflags field
   */
  #define FS_XFLAG_REALTIME	0x00000001	/* data in realtime volume */
  #define FS_XFLAG_PREALLOC	0x00000002	/* preallocated file extents */
  #define FS_XFLAG_IMMUTABLE	0x00000008	/* file cannot be modified */
  #define FS_XFLAG_APPEND		0x00000010	/* all writes append */
  #define FS_XFLAG_SYNC		0x00000020	/* all writes synchronous */
  #define FS_XFLAG_NOATIME	0x00000040	/* do not update access time */
  #define FS_XFLAG_NODUMP		0x00000080	/* do not include in backups */
  #define FS_XFLAG_RTINHERIT	0x00000100	/* create with rt bit set */
  #define FS_XFLAG_PROJINHERIT	0x00000200	/* create with parents projid */
  #define FS_XFLAG_NOSYMLINKS	0x00000400	/* disallow symlink creation */
  #define FS_XFLAG_EXTSIZE	0x00000800	/* extent size allocator hint */
  #define FS_XFLAG_EXTSZINHERIT	0x00001000	/* inherit inode extent size */
  #define FS_XFLAG_NODEFRAG	0x00002000  	/* do not defragment */
  #define FS_XFLAG_FILESTREAM	0x00004000	/* use filestream allocator */
  #define FS_XFLAG_HASATTR	0x80000000	/* no DIFLAG for this */
  #endif /* !defined(FS_IOC_FSGETXATTR) */
  
  #define EXT4_IOC_FSGETXATTR		FS_IOC_FSGETXATTR
  #define EXT4_IOC_FSSETXATTR		FS_IOC_FSSETXATTR

  #define EXT4_IOC_SHUTDOWN _IOR ('X', 125, __u32)

  
  /*
   * Flags for going down operation
   */
  #define EXT4_GOING_FLAGS_DEFAULT		0x0	/* going down */
  #define EXT4_GOING_FLAGS_LOGFLUSH		0x1	/* flush log but not data */
  #define EXT4_GOING_FLAGS_NOLOGFLUSH		0x2	/* don't flush log nor data */

  #if defined(__KERNEL__) && defined(CONFIG_COMPAT)

  /*
   * ioctl commands in 32 bit emulation
   */

  #define EXT4_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
  #define EXT4_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
  #define EXT4_IOC32_GETVERSION		_IOR('f', 3, int)
  #define EXT4_IOC32_SETVERSION		_IOW('f', 4, int)
  #define EXT4_IOC32_GETRSVSZ		_IOR('f', 5, int)
  #define EXT4_IOC32_SETRSVSZ		_IOW('f', 6, int)
  #define EXT4_IOC32_GROUP_EXTEND		_IOW('f', 7, unsigned int)

  #define EXT4_IOC32_GROUP_ADD		_IOW('f', 8, struct compat_ext4_new_group_input)

  #define EXT4_IOC32_GETVERSION_OLD	FS_IOC32_GETVERSION
  #define EXT4_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION

  #endif

  /* Max physical block we can address w/o extents */

  #define EXT4_MAX_BLOCK_FILE_PHYS	0xFFFFFFFF

  /* Max logical block we can support */
  #define EXT4_MAX_LOGICAL_BLOCK		0xFFFFFFFF

  /*
   * Structure of an inode on the disk
   */

  struct ext4_inode {

  	__le16	i_mode;		/* File mode */
  	__le16	i_uid;		/* Low 16 bits of Owner Uid */

  	__le32	i_size_lo;	/* Size in bytes */

  	__le32	i_atime;	/* Access time */

  	__le32	i_ctime;	/* Inode Change time */

  	__le32	i_mtime;	/* Modification time */
  	__le32	i_dtime;	/* Deletion Time */
  	__le16	i_gid;		/* Low 16 bits of Group Id */
  	__le16	i_links_count;	/* Links count */

  	__le32	i_blocks_lo;	/* Blocks count */

  	__le32	i_flags;	/* File flags */
  	union {
  		struct {

  			__le32  l_i_version;

  		} linux1;
  		struct {
  			__u32  h_i_translator;
  		} hurd1;
  		struct {
  			__u32  m_i_reserved1;
  		} masix1;
  	} osd1;				/* OS dependent 1 */

  	__le32	i_block[EXT4_N_BLOCKS];/* Pointers to blocks */

  	__le32	i_generation;	/* File version (for NFS) */

  	__le32	i_file_acl_lo;	/* File ACL */

  	__le32	i_size_high;

  	__le32	i_obso_faddr;	/* Obsoleted fragment address */

  	union {
  		struct {

  			__le16	l_i_blocks_high; /* were l_i_reserved1 */

  			__le16	l_i_file_acl_high;

  			__le16	l_i_uid_high;	/* these 2 fields */

  			__le16	l_i_gid_high;	/* were reserved2[0] */

  			__le16	l_i_checksum_lo;/* crc32c(uuid+inum+inode) LE */
  			__le16	l_i_reserved;

  		} linux2;
  		struct {

  			__le16	h_i_reserved1;	/* Obsoleted fragment number/size which are removed in ext4 */

  			__u16	h_i_mode_high;
  			__u16	h_i_uid_high;
  			__u16	h_i_gid_high;
  			__u32	h_i_author;
  		} hurd2;
  		struct {

  			__le16	h_i_reserved1;	/* Obsoleted fragment number/size which are removed in ext4 */

  			__le16	m_i_file_acl_high;

  			__u32	m_i_reserved2[2];
  		} masix2;
  	} osd2;				/* OS dependent 2 */
  	__le16	i_extra_isize;

  	__le16	i_checksum_hi;	/* crc32c(uuid+inum+inode) BE */

  	__le32  i_ctime_extra;  /* extra Change time      (nsec << 2 | epoch) */
  	__le32  i_mtime_extra;  /* extra Modification time(nsec << 2 | epoch) */
  	__le32  i_atime_extra;  /* extra Access time      (nsec << 2 | epoch) */
  	__le32  i_crtime;       /* File Creation time */
  	__le32  i_crtime_extra; /* extra FileCreationtime (nsec << 2 | epoch) */

  	__le32  i_version_hi;	/* high 32 bits for 64-bit version */

  	__le32	i_projid;	/* Project ID */

  };

  struct move_extent {
  	__u32 reserved;		/* should be zero */
  	__u32 donor_fd;		/* donor file descriptor */
  	__u64 orig_start;	/* logical start offset in block for orig */
  	__u64 donor_start;	/* logical start offset in block for donor */
  	__u64 len;		/* block length to be moved */
  	__u64 moved_len;	/* moved block length */
  };

  #define EXT4_EPOCH_BITS 2
  #define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
  #define EXT4_NSEC_MASK  (~0UL << EXT4_EPOCH_BITS)
  
  /*
   * Extended fields will fit into an inode if the filesystem was formatted
   * with large inodes (-I 256 or larger) and there are not currently any EAs
   * consuming all of the available space. For new inodes we always reserve
   * enough space for the kernel's known extended fields, but for inodes
   * created with an old kernel this might not have been the case. None of
   * the extended inode fields is critical for correct filesystem operation.
   * This macro checks if a certain field fits in the inode. Note that
   * inode-size = GOOD_OLD_INODE_SIZE + i_extra_isize
   */
  #define EXT4_FITS_IN_INODE(ext4_inode, einode, field)	\
  	((offsetof(typeof(*ext4_inode), field) +	\
  	  sizeof((ext4_inode)->field))			\
  	<= (EXT4_GOOD_OLD_INODE_SIZE +			\
  	    (einode)->i_extra_isize))			\

  /*
   * We use an encoding that preserves the times for extra epoch "00":
   *
   * extra  msb of                         adjust for signed
   * epoch  32-bit                         32-bit tv_sec to
   * bits   time    decoded 64-bit tv_sec  64-bit tv_sec      valid time range
   * 0 0    1    -0x80000000..-0x00000001  0x000000000 1901-12-13..1969-12-31
   * 0 0    0    0x000000000..0x07fffffff  0x000000000 1970-01-01..2038-01-19
   * 0 1    1    0x080000000..0x0ffffffff  0x100000000 2038-01-19..2106-02-07
   * 0 1    0    0x100000000..0x17fffffff  0x100000000 2106-02-07..2174-02-25
   * 1 0    1    0x180000000..0x1ffffffff  0x200000000 2174-02-25..2242-03-16
   * 1 0    0    0x200000000..0x27fffffff  0x200000000 2242-03-16..2310-04-04
   * 1 1    1    0x280000000..0x2ffffffff  0x300000000 2310-04-04..2378-04-22
   * 1 1    0    0x300000000..0x37fffffff  0x300000000 2378-04-22..2446-05-10
   *
   * Note that previous versions of the kernel on 64-bit systems would
   * incorrectly use extra epoch bits 1,1 for dates between 1901 and
   * 1970.  e2fsck will correct this, assuming that it is run on the
   * affected filesystem before 2242.
   */

  static inline __le32 ext4_encode_extra_time(struct timespec *time)
  {

  	u32 extra = sizeof(time->tv_sec) > 4 ?
  		((time->tv_sec - (s32)time->tv_sec) >> 32) & EXT4_EPOCH_MASK : 0;
  	return cpu_to_le32(extra | (time->tv_nsec << EXT4_EPOCH_BITS));

  }
  
  static inline void ext4_decode_extra_time(struct timespec *time, __le32 extra)
  {

  	if (unlikely(sizeof(time->tv_sec) > 4 &&
  			(extra & cpu_to_le32(EXT4_EPOCH_MASK)))) {

  
  #if 1

  		/* Handle legacy encoding of pre-1970 dates with epoch

  		 * bits 1,1. (This backwards compatibility may be removed
  		 * at the discretion of the ext4 developers.)

  		 */
  		u64 extra_bits = le32_to_cpu(extra) & EXT4_EPOCH_MASK;
  		if (extra_bits == 3 && ((time->tv_sec) & 0x80000000) != 0)
  			extra_bits = 0;
  		time->tv_sec += extra_bits << 32;
  #else
  		time->tv_sec += (u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK) << 32;
  #endif
  	}
  	time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> EXT4_EPOCH_BITS;

  }
  
  #define EXT4_INODE_SET_XTIME(xtime, inode, raw_inode)			       \
  do {									       \
  	(raw_inode)->xtime = cpu_to_le32((inode)->xtime.tv_sec);	       \
  	if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra))     \
  		(raw_inode)->xtime ## _extra =				       \
  				ext4_encode_extra_time(&(inode)->xtime);       \
  } while (0)
  
  #define EXT4_EINODE_SET_XTIME(xtime, einode, raw_inode)			       \
  do {									       \
  	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime))		       \
  		(raw_inode)->xtime = cpu_to_le32((einode)->xtime.tv_sec);      \
  	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra))	       \
  		(raw_inode)->xtime ## _extra =				       \
  				ext4_encode_extra_time(&(einode)->xtime);      \
  } while (0)
  
  #define EXT4_INODE_GET_XTIME(xtime, inode, raw_inode)			       \
  do {									       \
  	(inode)->xtime.tv_sec = (signed)le32_to_cpu((raw_inode)->xtime);       \
  	if (EXT4_FITS_IN_INODE(raw_inode, EXT4_I(inode), xtime ## _extra))     \
  		ext4_decode_extra_time(&(inode)->xtime,			       \
  				       raw_inode->xtime ## _extra);	       \

  	else								       \
  		(inode)->xtime.tv_nsec = 0;				       \

  } while (0)
  
  #define EXT4_EINODE_GET_XTIME(xtime, einode, raw_inode)			       \
  do {									       \
  	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime))		       \
  		(einode)->xtime.tv_sec = 				       \
  			(signed)le32_to_cpu((raw_inode)->xtime);	       \

  	else								       \
  		(einode)->xtime.tv_sec = 0;				       \

  	if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra))	       \
  		ext4_decode_extra_time(&(einode)->xtime,		       \
  				       raw_inode->xtime ## _extra);	       \

  	else								       \
  		(einode)->xtime.tv_nsec = 0;				       \

  } while (0)

  #define i_disk_version osd1.linux1.l_i_version

  #if defined(__KERNEL__) || defined(__linux__)
  #define i_reserved1	osd1.linux1.l_i_reserved1

  #define i_file_acl_high	osd2.linux2.l_i_file_acl_high

  #define i_blocks_high	osd2.linux2.l_i_blocks_high

  #define i_uid_low	i_uid
  #define i_gid_low	i_gid
  #define i_uid_high	osd2.linux2.l_i_uid_high
  #define i_gid_high	osd2.linux2.l_i_gid_high

  #define i_checksum_lo	osd2.linux2.l_i_checksum_lo

  
  #elif defined(__GNU__)
  
  #define i_translator	osd1.hurd1.h_i_translator

  #define i_uid_high	osd2.hurd2.h_i_uid_high
  #define i_gid_high	osd2.hurd2.h_i_gid_high
  #define i_author	osd2.hurd2.h_i_author
  
  #elif defined(__masix__)
  
  #define i_reserved1	osd1.masix1.m_i_reserved1

  #define i_file_acl_high	osd2.masix2.m_i_file_acl_high

  #define i_reserved2	osd2.masix2.m_i_reserved2
  
  #endif /* defined(__KERNEL__) || defined(__linux__) */

  #include "extents_status.h"

  /*

   * Lock subclasses for i_data_sem in the ext4_inode_info structure.
   *
   * These are needed to avoid lockdep false positives when we need to
   * allocate blocks to the quota inode during ext4_map_blocks(), while
   * holding i_data_sem for a normal (non-quota) inode.  Since we don't
   * do quota tracking for the quota inode, this avoids deadlock (as
   * well as infinite recursion, since it isn't turtles all the way
   * down...)
   *
   *  I_DATA_SEM_NORMAL - Used for most inodes
   *  I_DATA_SEM_OTHER  - Used by move_inode.c for the second normal inode
   *			  where the second inode has larger inode number
   *			  than the first
   *  I_DATA_SEM_QUOTA  - Used for quota inodes only
   */
  enum {
  	I_DATA_SEM_NORMAL = 0,
  	I_DATA_SEM_OTHER,
  	I_DATA_SEM_QUOTA,
  };
  
  
  /*

   * fourth extended file system inode data in memory
   */
  struct ext4_inode_info {
  	__le32	i_data[15];	/* unconverted */

  	__u32	i_dtime;

  	ext4_fsblk_t	i_file_acl;

  
  	/*
  	 * i_block_group is the number of the block group which contains
  	 * this file's inode.  Constant across the lifetime of the inode,

  	 * it is used for making block allocation decisions - we try to

  	 * place a file's data blocks near its inode block, and new inodes
  	 * near to their parent directory's inode.
  	 */
  	ext4_group_t	i_block_group;

  	ext4_lblk_t	i_dir_start_lookup;

  #if (BITS_PER_LONG < 64)

  	unsigned long	i_state_flags;		/* Dynamic state flags */

  #endif

  	unsigned long	i_flags;

  	/*
  	 * Extended attributes can be read independently of the main file
  	 * data. Taking i_mutex even when reading would cause contention
  	 * between readers of EAs and writers of regular file data, so
  	 * instead we synchronize on xattr_sem when reading or changing
  	 * EAs.
  	 */
  	struct rw_semaphore xattr_sem;

  
  	struct list_head i_orphan;	/* unlinked but open inodes */
  
  	/*
  	 * i_disksize keeps track of what the inode size is ON DISK, not
  	 * in memory.  During truncate, i_size is set to the new size by
  	 * the VFS prior to calling ext4_truncate(), but the filesystem won't
  	 * set i_disksize to 0 until the truncate is actually under way.
  	 *
  	 * The intent is that i_disksize always represents the blocks which
  	 * are used by this file.  This allows recovery to restart truncate
  	 * on orphans if we crash during truncate.  We actually write i_disksize
  	 * into the on-disk inode when writing inodes out, instead of i_size.
  	 *
  	 * The only time when i_disksize and i_size may be different is when
  	 * a truncate is in progress.  The only things which change i_disksize
  	 * are ext4_get_block (growth) and ext4_truncate (shrinkth).
  	 */
  	loff_t	i_disksize;
  
  	/*
  	 * i_data_sem is for serialising ext4_truncate() against
  	 * ext4_getblock().  In the 2.4 ext2 design, great chunks of inode's
  	 * data tree are chopped off during truncate. We can't do that in
  	 * ext4 because whenever we perform intermediate commits during
  	 * truncate, the inode and all the metadata blocks *must* be in a
  	 * consistent state which allows truncation of the orphans to restart
  	 * during recovery.  Hence we must fix the get_block-vs-truncate race
  	 * by other means, so we have i_data_sem.
  	 */
  	struct rw_semaphore i_data_sem;

  	/*
  	 * i_mmap_sem is for serializing page faults with truncate / punch hole
  	 * operations. We have to make sure that new page cannot be faulted in
  	 * a section of the inode that is being punched. We cannot easily use
  	 * i_data_sem for this since we need protection for the whole punch
  	 * operation and i_data_sem ranks below transaction start so we have
  	 * to occasionally drop it.
  	 */
  	struct rw_semaphore i_mmap_sem;

  	struct inode vfs_inode;

  	struct jbd2_inode *jinode;

  	spinlock_t i_raw_lock;	/* protects updates to the raw inode */

  	/*
  	 * File creation time. Its function is same as that of
  	 * struct timespec i_{a,c,m}time in the generic inode.
  	 */
  	struct timespec i_crtime;
  
  	/* mballoc */
  	struct list_head i_prealloc_list;
  	spinlock_t i_prealloc_lock;

  	/* extents status tree */
  	struct ext4_es_tree i_es_tree;
  	rwlock_t i_es_lock;

  	struct list_head i_es_list;

  	unsigned int i_es_all_nr;	/* protected by i_es_lock */

  	unsigned int i_es_shk_nr;	/* protected by i_es_lock */

  	ext4_lblk_t i_es_shrink_lblk;	/* Offset where we start searching for
  					   extents to shrink. Protected by
  					   i_es_lock  */

  	/* ialloc */
  	ext4_group_t	i_last_alloc_group;
  
  	/* allocation reservation info for delalloc */

  	/* In case of bigalloc, this refer to clusters rather than blocks */

  	unsigned int i_reserved_data_blocks;

  	ext4_lblk_t i_da_metadata_calc_last_lblock;

  	int i_da_metadata_calc_len;

  
  	/* on-disk additional length */
  	__u16 i_extra_isize;

  	/* Indicate the inline data space. */
  	u16 i_inline_off;
  	u16 i_inline_size;

  #ifdef CONFIG_QUOTA
  	/* quota space reservation, managed internally by quota code */
  	qsize_t i_reserved_quota;
  #endif

  	/* Lock protecting lists below */

  	spinlock_t i_completed_io_lock;

  	/*
  	 * Completed IOs that need unwritten extents handling and have
  	 * transaction reserved
  	 */
  	struct list_head i_rsv_conversion_list;

  	struct work_struct i_rsv_conversion_work;

  	atomic_t i_unwritten; /* Nr. of inflight conversions pending */

  
  	spinlock_t i_block_reservation_lock;

  
  	/*
  	 * Transactions that contain inode's metadata needed to complete
  	 * fsync and fdatasync, respectively.
  	 */
  	tid_t i_sync_tid;
  	tid_t i_datasync_tid;

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

  	/* Precomputed uuid+inum+igen checksum for seeding inode checksums */
  	__u32 i_csum_seed;

  	kprojid_t i_projid;

  };
  
  /*

   * File system states
   */

  #define	EXT4_VALID_FS			0x0001	/* Unmounted cleanly */
  #define	EXT4_ERROR_FS			0x0002	/* Errors detected */
  #define	EXT4_ORPHAN_FS			0x0004	/* Orphans being recovered */

  
  /*

   * Misc. filesystem flags
   */
  #define EXT2_FLAGS_SIGNED_HASH		0x0001  /* Signed dirhash in use */
  #define EXT2_FLAGS_UNSIGNED_HASH	0x0002  /* Unsigned dirhash in use */
  #define EXT2_FLAGS_TEST_FILESYS		0x0004	/* to test development code */
  
  /*

   * Mount flags set via mount options or defaults

   */

  #define EXT4_MOUNT_NO_MBCACHE		0x00001 /* Do not use mbcache */

  #define EXT4_MOUNT_GRPID		0x00004	/* Create files with directory's group */
  #define EXT4_MOUNT_DEBUG		0x00008	/* Some debugging messages */
  #define EXT4_MOUNT_ERRORS_CONT		0x00010	/* Continue on errors */
  #define EXT4_MOUNT_ERRORS_RO		0x00020	/* Remount fs ro on errors */
  #define EXT4_MOUNT_ERRORS_PANIC		0x00040	/* Panic on errors */

  #define EXT4_MOUNT_ERRORS_MASK		0x00070

  #define EXT4_MOUNT_MINIX_DF		0x00080	/* Mimics the Minix statfs */
  #define EXT4_MOUNT_NOLOAD		0x00100	/* Don't use existing journal*/

  #ifdef CONFIG_FS_DAX
  #define EXT4_MOUNT_DAX			0x00200	/* Direct Access */
  #else
  #define EXT4_MOUNT_DAX			0
  #endif

  #define EXT4_MOUNT_DATA_FLAGS		0x00C00	/* Mode for data writes: */
  #define EXT4_MOUNT_JOURNAL_DATA		0x00400	/* Write data to journal */
  #define EXT4_MOUNT_ORDERED_DATA		0x00800	/* Flush data before commit */
  #define EXT4_MOUNT_WRITEBACK_DATA	0x00C00	/* No data ordering */
  #define EXT4_MOUNT_UPDATE_JOURNAL	0x01000	/* Update the journal format */
  #define EXT4_MOUNT_NO_UID32		0x02000  /* Disable 32-bit UIDs */
  #define EXT4_MOUNT_XATTR_USER		0x04000	/* Extended user attributes */
  #define EXT4_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */

  #define EXT4_MOUNT_NO_AUTO_DA_ALLOC	0x10000	/* No auto delalloc mapping */

  #define EXT4_MOUNT_BARRIER		0x20000 /* Use block barriers */

  #define EXT4_MOUNT_QUOTA		0x40000 /* Some quota option set */
  #define EXT4_MOUNT_USRQUOTA		0x80000 /* "old" user quota,
  						 * enable enforcement for hidden
  						 * quota files */
  #define EXT4_MOUNT_GRPQUOTA		0x100000 /* "old" group quota, enable
  						  * enforcement for hidden quota
  						  * files */
  #define EXT4_MOUNT_PRJQUOTA		0x200000 /* Enable project quota
  						  * enforcement */

  #define EXT4_MOUNT_DIOREAD_NOLOCK	0x400000 /* Enable support for dio read nolocking */

  #define EXT4_MOUNT_JOURNAL_CHECKSUM	0x800000 /* Journal checksums */

  #define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT	0x1000000 /* Journal Async Commit */

  #define EXT4_MOUNT_DELALLOC		0x8000000 /* Delalloc support */

  #define EXT4_MOUNT_DATA_ERR_ABORT	0x10000000 /* Abort on file data write */

  #define EXT4_MOUNT_BLOCK_VALIDITY	0x20000000 /* Block validity checking */

  #define EXT4_MOUNT_DISCARD		0x40000000 /* Issue DISCARD requests */

  #define EXT4_MOUNT_INIT_INODE_TABLE	0x80000000 /* Initialize uninitialized itables */

  /*
   * Mount flags set either automatically (could not be set by mount option)
   * based on per file system feature or property or in special cases such as
   * distinguishing between explicit mount option definition and default.
   */

  #define EXT4_MOUNT2_EXPLICIT_DELALLOC	0x00000001 /* User explicitly
  						      specified delalloc */

  #define EXT4_MOUNT2_STD_GROUP_SIZE	0x00000002 /* We have standard group
  						      size of blocksize * 8
  						      blocks */

  #define EXT4_MOUNT2_HURD_COMPAT		0x00000004 /* Support HURD-castrated
  						      file systems */

  #define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM	0x00000008 /* User explicitly
  						specified journal checksum */

  #define clear_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt &= \
  						~EXT4_MOUNT_##opt
  #define set_opt(sb, opt)		EXT4_SB(sb)->s_mount_opt |= \
  						EXT4_MOUNT_##opt

  #define test_opt(sb, opt)		(EXT4_SB(sb)->s_mount_opt & \
  					 EXT4_MOUNT_##opt)

  #define clear_opt2(sb, opt)		EXT4_SB(sb)->s_mount_opt2 &= \
  						~EXT4_MOUNT2_##opt
  #define set_opt2(sb, opt)		EXT4_SB(sb)->s_mount_opt2 |= \
  						EXT4_MOUNT2_##opt
  #define test_opt2(sb, opt)		(EXT4_SB(sb)->s_mount_opt2 & \
  					 EXT4_MOUNT2_##opt)

  #define ext4_test_and_set_bit		__test_and_set_bit_le
  #define ext4_set_bit			__set_bit_le

  #define ext4_set_bit_atomic		ext2_set_bit_atomic

  #define ext4_test_and_clear_bit		__test_and_clear_bit_le
  #define ext4_clear_bit			__clear_bit_le

  #define ext4_clear_bit_atomic		ext2_clear_bit_atomic

  #define ext4_test_bit			test_bit_le

  #define ext4_find_next_zero_bit		find_next_zero_bit_le
  #define ext4_find_next_bit		find_next_bit_le

  extern void ext4_set_bits(void *bm, int cur, int len);

  /*
   * Maximal mount counts between two filesystem checks
   */

  #define EXT4_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
  #define EXT4_DFL_CHECKINTERVAL		0	/* Don't use interval check */

  
  /*
   * Behaviour when detecting errors
   */

  #define EXT4_ERRORS_CONTINUE		1	/* Continue execution */
  #define EXT4_ERRORS_RO			2	/* Remount fs read-only */
  #define EXT4_ERRORS_PANIC		3	/* Panic */
  #define EXT4_ERRORS_DEFAULT		EXT4_ERRORS_CONTINUE

  /* Metadata checksum algorithm codes */
  #define EXT4_CRC32C_CHKSUM		1

  /*
   * Structure of the super block
   */

  struct ext4_super_block {

  /*00*/	__le32	s_inodes_count;		/* Inodes count */

  	__le32	s_blocks_count_lo;	/* Blocks count */

  	__le32	s_r_blocks_count_lo;	/* Reserved blocks count */
  	__le32	s_free_blocks_count_lo;	/* Free blocks count */

  /*10*/	__le32	s_free_inodes_count;	/* Free inodes count */
  	__le32	s_first_data_block;	/* First Data Block */
  	__le32	s_log_block_size;	/* Block size */

  	__le32	s_log_cluster_size;	/* Allocation cluster size */

  /*20*/	__le32	s_blocks_per_group;	/* # Blocks per group */

  	__le32	s_clusters_per_group;	/* # Clusters per group */

  	__le32	s_inodes_per_group;	/* # Inodes per group */
  	__le32	s_mtime;		/* Mount time */
  /*30*/	__le32	s_wtime;		/* Write time */
  	__le16	s_mnt_count;		/* Mount count */
  	__le16	s_max_mnt_count;	/* Maximal mount count */
  	__le16	s_magic;		/* Magic signature */
  	__le16	s_state;		/* File system state */
  	__le16	s_errors;		/* Behaviour when detecting errors */
  	__le16	s_minor_rev_level;	/* minor revision level */
  /*40*/	__le32	s_lastcheck;		/* time of last check */
  	__le32	s_checkinterval;	/* max. time between checks */
  	__le32	s_creator_os;		/* OS */
  	__le32	s_rev_level;		/* Revision level */
  /*50*/	__le16	s_def_resuid;		/* Default uid for reserved blocks */
  	__le16	s_def_resgid;		/* Default gid for reserved blocks */
  	/*

  	 * These fields are for EXT4_DYNAMIC_REV superblocks only.

  	 *
  	 * Note: the difference between the compatible feature set and
  	 * the incompatible feature set is that if there is a bit set
  	 * in the incompatible feature set that the kernel doesn't
  	 * know about, it should refuse to mount the filesystem.
  	 *
  	 * e2fsck's requirements are more strict; if it doesn't know
  	 * about a feature in either the compatible or incompatible
  	 * feature set, it must abort and not try to meddle with
  	 * things it doesn't understand...
  	 */
  	__le32	s_first_ino;		/* First non-reserved inode */

  	__le16  s_inode_size;		/* size of inode structure */

  	__le16	s_block_group_nr;	/* block group # of this superblock */
  	__le32	s_feature_compat;	/* compatible feature set */
  /*60*/	__le32	s_feature_incompat;	/* incompatible feature set */
  	__le32	s_feature_ro_compat;	/* readonly-compatible feature set */
  /*68*/	__u8	s_uuid[16];		/* 128-bit uuid for volume */
  /*78*/	char	s_volume_name[16];	/* volume name */
  /*88*/	char	s_last_mounted[64];	/* directory where last mounted */
  /*C8*/	__le32	s_algorithm_usage_bitmap; /* For compression */
  	/*
  	 * Performance hints.  Directory preallocation should only

  	 * happen if the EXT4_FEATURE_COMPAT_DIR_PREALLOC flag is on.

  	 */
  	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
  	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
  	__le16	s_reserved_gdt_blocks;	/* Per group desc for online growth */
  	/*

  	 * Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.

  	 */
  /*D0*/	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
  /*E0*/	__le32	s_journal_inum;		/* inode number of journal file */
  	__le32	s_journal_dev;		/* device number of journal file */
  	__le32	s_last_orphan;		/* start of list of inodes to delete */
  	__le32	s_hash_seed[4];		/* HTREE hash seed */
  	__u8	s_def_hash_version;	/* Default hash version to use */

  	__u8	s_jnl_backup_type;

  	__le16  s_desc_size;		/* size of group descriptor */

  /*100*/	__le32	s_default_mount_opts;

  	__le32	s_first_meta_bg;	/* First metablock block group */

  	__le32	s_mkfs_time;		/* When the filesystem was created */
  	__le32	s_jnl_blocks[17];	/* Backup of the journal inode */
  	/* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
  /*150*/	__le32	s_blocks_count_hi;	/* Blocks count */
  	__le32	s_r_blocks_count_hi;	/* Reserved blocks count */
  	__le32	s_free_blocks_count_hi;	/* Free blocks count */

  	__le16	s_min_extra_isize;	/* All inodes have at least # bytes */
  	__le16	s_want_extra_isize; 	/* New inodes should reserve # bytes */
  	__le32	s_flags;		/* Miscellaneous flags */
  	__le16  s_raid_stride;		/* RAID stride */

  	__le16  s_mmp_update_interval;  /* # seconds to wait in MMP checking */

  	__le64  s_mmp_block;            /* Block for multi-mount protection */
  	__le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/

  	__u8	s_log_groups_per_flex;  /* FLEX_BG group size */

  	__u8	s_checksum_type;	/* metadata checksum algorithm used */

  	__u8	s_encryption_level;	/* versioning level for encryption */
  	__u8	s_reserved_pad;		/* Padding to next 32bits */

  	__le64	s_kbytes_written;	/* nr of lifetime kilobytes written */

  	__le32	s_snapshot_inum;	/* Inode number of active snapshot */
  	__le32	s_snapshot_id;		/* sequential ID of active snapshot */
  	__le64	s_snapshot_r_blocks_count; /* reserved blocks for active
  					      snapshot's future use */
  	__le32	s_snapshot_list;	/* inode number of the head of the
  					   on-disk snapshot list */

  #define EXT4_S_ERR_START offsetof(struct ext4_super_block, s_error_count)
  	__le32	s_error_count;		/* number of fs errors */
  	__le32	s_first_error_time;	/* first time an error happened */
  	__le32	s_first_error_ino;	/* inode involved in first error */
  	__le64	s_first_error_block;	/* block involved of first error */
  	__u8	s_first_error_func[32];	/* function where the error happened */
  	__le32	s_first_error_line;	/* line number where error happened */
  	__le32	s_last_error_time;	/* most recent time of an error */
  	__le32	s_last_error_ino;	/* inode involved in last error */
  	__le32	s_last_error_line;	/* line number where error happened */
  	__le64	s_last_error_block;	/* block involved of last error */
  	__u8	s_last_error_func[32];	/* function where the error happened */

  #define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_mount_opts)
  	__u8	s_mount_opts[64];

  	__le32	s_usr_quota_inum;	/* inode for tracking user quota */
  	__le32	s_grp_quota_inum;	/* inode for tracking group quota */
  	__le32	s_overhead_clusters;	/* overhead blocks/clusters in fs */

  	__le32	s_backup_bgs[2];	/* groups with sparse_super2 SBs */

  	__u8	s_encrypt_algos[4];	/* Encryption algorithms in use  */

  	__u8	s_encrypt_pw_salt[16];	/* Salt used for string2key algorithm */
  	__le32	s_lpf_ino;		/* Location of the lost+found inode */

  	__le32	s_prj_quota_inum;	/* inode for tracking project quota */

  	__le32	s_checksum_seed;	/* crc32c(uuid) if csum_seed set */
  	__le32	s_reserved[98];		/* Padding to the end of the block */

  	__le32	s_checksum;		/* crc32c(superblock) */

  };

  #define EXT4_S_ERR_LEN (EXT4_S_ERR_END - EXT4_S_ERR_START)

  #ifdef __KERNEL__

  
  /*

   * run-time mount flags

   */

  #define EXT4_MF_MNTDIR_SAMPLED		0x0001
  #define EXT4_MF_FS_ABORTED		0x0002	/* Fatal error detected */
  #define EXT4_MF_TEST_DUMMY_ENCRYPTION	0x0004
  
  #ifdef CONFIG_EXT4_FS_ENCRYPTION
  #define DUMMY_ENCRYPTION_ENABLED(sbi) (unlikely((sbi)->s_mount_flags & \
  						EXT4_MF_TEST_DUMMY_ENCRYPTION))
  #else
  #define DUMMY_ENCRYPTION_ENABLED(sbi) (0)
  #endif

  /* Number of quota types we support */

  #define EXT4_MAXQUOTAS 3

  /*
   * fourth extended-fs super-block data in memory
   */
  struct ext4_sb_info {
  	unsigned long s_desc_size;	/* Size of a group descriptor in bytes */
  	unsigned long s_inodes_per_block;/* Number of inodes per block */
  	unsigned long s_blocks_per_group;/* Number of blocks in a group */

  	unsigned long s_clusters_per_group; /* Number of clusters in a group */

  	unsigned long s_inodes_per_group;/* Number of inodes in a group */
  	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
  	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
  	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
  	ext4_group_t s_groups_count;	/* Number of groups in the fs */

  	ext4_group_t s_blockfile_groups;/* Groups acceptable for non-extent files */

  	unsigned long s_overhead;  /* # of fs overhead clusters */

  	unsigned int s_cluster_ratio;	/* Number of blocks per cluster */
  	unsigned int s_cluster_bits;	/* log2 of s_cluster_ratio */

  	loff_t s_bitmap_maxbytes;	/* max bytes for bitmap files */
  	struct buffer_head * s_sbh;	/* Buffer containing the super block */
  	struct ext4_super_block *s_es;	/* Pointer to the super block in the buffer */
  	struct buffer_head **s_group_desc;

  	unsigned int s_mount_opt;

  	unsigned int s_mount_opt2;

  	unsigned int s_mount_flags;

  	unsigned int s_def_mount_opt;

  	ext4_fsblk_t s_sb_block;

  	atomic64_t s_resv_clusters;

  	kuid_t s_resuid;
  	kgid_t s_resgid;

  	unsigned short s_mount_state;
  	unsigned short s_pad;
  	int s_addr_per_block_bits;
  	int s_desc_per_block_bits;
  	int s_inode_size;
  	int s_first_ino;
  	unsigned int s_inode_readahead_blks;

  	unsigned int s_inode_goal;

  	spinlock_t s_next_gen_lock;
  	u32 s_next_generation;
  	u32 s_hash_seed[4];
  	int s_def_hash_version;
  	int s_hash_unsigned;	/* 3 if hash should be signed, 0 if not */

  	struct percpu_counter s_freeclusters_counter;

  	struct percpu_counter s_freeinodes_counter;
  	struct percpu_counter s_dirs_counter;

  	struct percpu_counter s_dirtyclusters_counter;

  	struct blockgroup_lock *s_blockgroup_lock;
  	struct proc_dir_entry *s_proc;
  	struct kobject s_kobj;
  	struct completion s_kobj_unregister;

  	struct super_block *s_sb;

  
  	/* Journaling */

  	struct journal_s *s_journal;
  	struct list_head s_orphan;
  	struct mutex s_orphan_lock;

  	unsigned long s_ext4_flags;		/* Ext4 superblock flags */

  	unsigned long s_commit_interval;
  	u32 s_max_batch_time;
  	u32 s_min_batch_time;
  	struct block_device *journal_bdev;

  #ifdef CONFIG_QUOTA

  	/* Names of quota files with journalled quota */
  	char __rcu *s_qf_names[EXT4_MAXQUOTAS];

  	int s_jquota_fmt;			/* Format of quota to use */
  #endif
  	unsigned int s_want_extra_isize; /* New inodes should reserve # bytes */

  	struct rb_root system_blks;

  
  #ifdef EXTENTS_STATS
  	/* ext4 extents stats */
  	unsigned long s_ext_min;
  	unsigned long s_ext_max;
  	unsigned long s_depth_max;
  	spinlock_t s_ext_stats_lock;
  	unsigned long s_ext_blocks;
  	unsigned long s_ext_extents;
  #endif
  
  	/* for buddy allocator */
  	struct ext4_group_info ***s_group_info;
  	struct inode *s_buddy_cache;

  	spinlock_t s_md_lock;

  	unsigned short *s_mb_offsets;
  	unsigned int *s_mb_maxs;

  	unsigned int s_group_info_size;

  	unsigned int s_mb_free_pending;

  	struct list_head s_freed_data_list;	/* List of blocks to be freed
  						   after commit completed */

  
  	/* tunables */
  	unsigned long s_stripe;
  	unsigned int s_mb_stream_request;
  	unsigned int s_mb_max_to_scan;
  	unsigned int s_mb_min_to_scan;
  	unsigned int s_mb_stats;
  	unsigned int s_mb_order2_reqs;
  	unsigned int s_mb_group_prealloc;

  	unsigned int s_max_dir_size_kb;

  	/* where last allocation was done - for stream allocation */
  	unsigned long s_mb_last_group;
  	unsigned long s_mb_last_start;

  	/* stats for buddy allocator */

  	atomic_t s_bal_reqs;	/* number of reqs with len > 1 */
  	atomic_t s_bal_success;	/* we found long enough chunks */
  	atomic_t s_bal_allocated;	/* in blocks */
  	atomic_t s_bal_ex_scanned;	/* total extents scanned */
  	atomic_t s_bal_goals;	/* goal hits */
  	atomic_t s_bal_breaks;	/* too long searches */
  	atomic_t s_bal_2orders;	/* 2^order hits */
  	spinlock_t s_bal_lock;
  	unsigned long s_mb_buddies_generated;
  	unsigned long long s_mb_generation_time;
  	atomic_t s_mb_lost_chunks;
  	atomic_t s_mb_preallocated;
  	atomic_t s_mb_discarded;

  	atomic_t s_lock_busy;

  
  	/* locality groups */

  	struct ext4_locality_group __percpu *s_locality_groups;

  
  	/* for write statistics */
  	unsigned long s_sectors_written_start;
  	u64 s_kbytes_written;

  	/* the size of zero-out chunk */
  	unsigned int s_extent_max_zeroout_kb;

  	unsigned int s_log_groups_per_flex;
  	struct flex_groups *s_flex_groups;

  	ext4_group_t s_flex_groups_allocated;

  	/* workqueue for reserved extent conversions (buffered io) */
  	struct workqueue_struct *rsv_conversion_wq;

  
  	/* timer for periodic error stats printing */
  	struct timer_list s_err_report;

  
  	/* Lazy inode table initialization info */
  	struct ext4_li_request *s_li_request;
  	/* Wait multiplier for lazy initialization thread */
  	unsigned int s_li_wait_mult;

  
  	/* Kernel thread for multiple mount protection */
  	struct task_struct *s_mmp_tsk;

  
  	/* record the last minlen when FITRIM is called. */
  	atomic_t s_last_trim_minblks;

  
  	/* Reference to checksum algorithm driver via cryptoapi */
  	struct crypto_shash *s_chksum_driver;

  
  	/* Precomputed FS UUID checksum for seeding other checksums */
  	__u32 s_csum_seed;

  
  	/* Reclaim extents from extent status tree */
  	struct shrinker s_es_shrinker;

  	struct list_head s_es_list;	/* List of inodes with reclaimable extents */

  	long s_es_nr_inode;

  	struct ext4_es_stats s_es_stats;

  	struct mb_cache *s_ea_block_cache;

  	struct mb_cache *s_ea_inode_cache;

  	spinlock_t s_es_lock ____cacheline_aligned_in_smp;

  
  	/* Ratelimit ext4 messages. */
  	struct ratelimit_state s_err_ratelimit_state;
  	struct ratelimit_state s_warning_ratelimit_state;
  	struct ratelimit_state s_msg_ratelimit_state;

  
  	/* Barrier between changing inodes' journal flags and writepages ops. */
  	struct percpu_rw_semaphore s_journal_flag_rwsem;

  	struct dax_device *s_daxdev;

  };

  static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)

  {
  	return sb->s_fs_info;
  }

  static inline struct ext4_inode_info *EXT4_I(struct inode *inode)

  {

  	return container_of(inode, struct ext4_inode_info, vfs_inode);

  }

  static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)

  {

  	return ino == EXT4_ROOT_INO ||

  		(ino >= EXT4_FIRST_INO(sb) &&
  		 ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));

  }

  
  /*
   * Inode dynamic state flags
   */
  enum {
  	EXT4_STATE_JDATA,		/* journaled data exists */
  	EXT4_STATE_NEW,			/* inode is newly created */
  	EXT4_STATE_XATTR,		/* has in-inode xattrs */
  	EXT4_STATE_NO_EXPAND,		/* No space for expansion */
  	EXT4_STATE_DA_ALLOC_CLOSE,	/* Alloc DA blks on close */
  	EXT4_STATE_EXT_MIGRATE,		/* Inode is migrating */
  	EXT4_STATE_DIO_UNWRITTEN,	/* need convert on dio done*/

  	EXT4_STATE_NEWENTRY,		/* File just added to dir */

  	EXT4_STATE_DIOREAD_LOCK,	/* Disable support for dio read
  					   nolocking */

  	EXT4_STATE_MAY_INLINE_DATA,	/* may have in-inode data */

  	EXT4_STATE_EXT_PRECACHED,	/* extents have been precached */

  	EXT4_STATE_LUSTRE_EA_INODE,	/* Lustre-style ea_inode */

  };

  #define EXT4_INODE_BIT_FNS(name, field, offset)				\

  static inline int ext4_test_inode_##name(struct inode *inode, int bit)	\
  {									\

  	return test_bit(bit + (offset), &EXT4_I(inode)->i_##field);	\

  }									\
  static inline void ext4_set_inode_##name(struct inode *inode, int bit)	\
  {									\

  	set_bit(bit + (offset), &EXT4_I(inode)->i_##field);		\

  }									\
  static inline void ext4_clear_inode_##name(struct inode *inode, int bit) \
  {									\

  	clear_bit(bit + (offset), &EXT4_I(inode)->i_##field);		\

  }

  /* Add these declarations here only so that these functions can be
   * found by name.  Otherwise, they are very hard to locate. */
  static inline int ext4_test_inode_flag(struct inode *inode, int bit);
  static inline void ext4_set_inode_flag(struct inode *inode, int bit);
  static inline void ext4_clear_inode_flag(struct inode *inode, int bit);

  EXT4_INODE_BIT_FNS(flag, flags, 0)

  
  /* Add these declarations here only so that these functions can be
   * found by name.  Otherwise, they are very hard to locate. */
  static inline int ext4_test_inode_state(struct inode *inode, int bit);
  static inline void ext4_set_inode_state(struct inode *inode, int bit);
  static inline void ext4_clear_inode_state(struct inode *inode, int bit);

  #if (BITS_PER_LONG < 64)
  EXT4_INODE_BIT_FNS(state, state_flags, 0)
  
  static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
  {
  	(ei)->i_state_flags = 0;
  }
  #else
  EXT4_INODE_BIT_FNS(state, flags, 32)
  
  static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
  {
  	/* We depend on the fact that callers will set i_flags */
  }
  #endif

  #else

  /* Assume that user mode programs are passing in an ext4fs superblock, not

   * a kernel struct super_block.  This will allow us to call the feature-test
   * macros from user land. */

  #define EXT4_SB(sb)	(sb)

  #endif

  /*
   * Returns true if the inode is inode is encrypted
   */

  #define NEXT_ORPHAN(inode) EXT4_I(inode)->i_dtime

  
  /*
   * Codes for operating systems
   */

  #define EXT4_OS_LINUX		0
  #define EXT4_OS_HURD		1
  #define EXT4_OS_MASIX		2
  #define EXT4_OS_FREEBSD		3
  #define EXT4_OS_LITES		4

  
  /*
   * Revision levels
   */

  #define EXT4_GOOD_OLD_REV	0	/* The good old (original) format */
  #define EXT4_DYNAMIC_REV	1	/* V2 format w/ dynamic inode sizes */

  #define EXT4_CURRENT_REV	EXT4_GOOD_OLD_REV
  #define EXT4_MAX_SUPP_REV	EXT4_DYNAMIC_REV

  #define EXT4_GOOD_OLD_INODE_SIZE 128

  
  /*
   * Feature set definitions
   */

  #define EXT4_FEATURE_COMPAT_DIR_PREALLOC	0x0001
  #define EXT4_FEATURE_COMPAT_IMAGIC_INODES	0x0002
  #define EXT4_FEATURE_COMPAT_HAS_JOURNAL		0x0004
  #define EXT4_FEATURE_COMPAT_EXT_ATTR		0x0008
  #define EXT4_FEATURE_COMPAT_RESIZE_INODE	0x0010
  #define EXT4_FEATURE_COMPAT_DIR_INDEX		0x0020

  #define EXT4_FEATURE_COMPAT_SPARSE_SUPER2	0x0200

  
  #define EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
  #define EXT4_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
  #define EXT4_FEATURE_RO_COMPAT_BTREE_DIR	0x0004

  #define EXT4_FEATURE_RO_COMPAT_HUGE_FILE        0x0008

  #define EXT4_FEATURE_RO_COMPAT_GDT_CSUM		0x0010

  #define EXT4_FEATURE_RO_COMPAT_DIR_NLINK	0x0020

  #define EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE	0x0040

  #define EXT4_FEATURE_RO_COMPAT_QUOTA		0x0100

  #define EXT4_FEATURE_RO_COMPAT_BIGALLOC		0x0200

  /*
   * METADATA_CSUM also enables group descriptor checksums (GDT_CSUM).  When
   * METADATA_CSUM is set, group descriptor checksums use the same algorithm as
   * all other data structures' checksums.  However, the METADATA_CSUM and
   * GDT_CSUM bits are mutually exclusive.
   */

  #define EXT4_FEATURE_RO_COMPAT_METADATA_CSUM	0x0400

  #define EXT4_FEATURE_RO_COMPAT_READONLY		0x1000

  #define EXT4_FEATURE_RO_COMPAT_PROJECT		0x2000

  
  #define EXT4_FEATURE_INCOMPAT_COMPRESSION	0x0001
  #define EXT4_FEATURE_INCOMPAT_FILETYPE		0x0002
  #define EXT4_FEATURE_INCOMPAT_RECOVER		0x0004 /* Needs recovery */
  #define EXT4_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008 /* Journal device */
  #define EXT4_FEATURE_INCOMPAT_META_BG		0x0010

  #define EXT4_FEATURE_INCOMPAT_EXTENTS		0x0040 /* extents support */

  #define EXT4_FEATURE_INCOMPAT_64BIT		0x0080

  #define EXT4_FEATURE_INCOMPAT_MMP               0x0100

  #define EXT4_FEATURE_INCOMPAT_FLEX_BG		0x0200

  #define EXT4_FEATURE_INCOMPAT_EA_INODE		0x0400 /* EA in inode */
  #define EXT4_FEATURE_INCOMPAT_DIRDATA		0x1000 /* data in dirent */

  #define EXT4_FEATURE_INCOMPAT_CSUM_SEED		0x2000

  #define EXT4_FEATURE_INCOMPAT_LARGEDIR		0x4000 /* >2GB or 3-lvl htree */

  #define EXT4_FEATURE_INCOMPAT_INLINE_DATA	0x8000 /* data in inode */

  #define EXT4_FEATURE_INCOMPAT_ENCRYPT		0x10000

  #define EXT4_FEATURE_COMPAT_FUNCS(name, flagname) \
  static inline bool ext4_has_feature_##name(struct super_block *sb) \
  { \
  	return ((EXT4_SB(sb)->s_es->s_feature_compat & \
  		cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname)) != 0); \
  } \
  static inline void ext4_set_feature_##name(struct super_block *sb) \
  { \
  	EXT4_SB(sb)->s_es->s_feature_compat |= \
  		cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname); \
  } \
  static inline void ext4_clear_feature_##name(struct super_block *sb) \
  { \
  	EXT4_SB(sb)->s_es->s_feature_compat &= \
  		~cpu_to_le32(EXT4_FEATURE_COMPAT_##flagname); \
  }
  
  #define EXT4_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
  static inline bool ext4_has_feature_##name(struct super_block *sb) \
  { \
  	return ((EXT4_SB(sb)->s_es->s_feature_ro_compat & \
  		cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname)) != 0); \
  } \
  static inline void ext4_set_feature_##name(struct super_block *sb) \
  { \
  	EXT4_SB(sb)->s_es->s_feature_ro_compat |= \
  		cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname); \
  } \
  static inline void ext4_clear_feature_##name(struct super_block *sb) \
  { \
  	EXT4_SB(sb)->s_es->s_feature_ro_compat &= \
  		~cpu_to_le32(EXT4_FEATURE_RO_COMPAT_##flagname); \
  }
  
  #define EXT4_FEATURE_INCOMPAT_FUNCS(name, flagname) \
  static inline bool ext4_has_feature_##name(struct super_block *sb) \
  { \
  	return ((EXT4_SB(sb)->s_es->s_feature_incompat & \
  		cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname)) != 0); \
  } \
  static inline void ext4_set_feature_##name(struct super_block *sb) \
  { \
  	EXT4_SB(sb)->s_es->s_feature_incompat |= \
  		cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname); \
  } \
  static inline void ext4_clear_feature_##name(struct super_block *sb) \
  { \
  	EXT4_SB(sb)->s_es->s_feature_incompat &= \
  		~cpu_to_le32(EXT4_FEATURE_INCOMPAT_##flagname); \
  }
  
  EXT4_FEATURE_COMPAT_FUNCS(dir_prealloc,		DIR_PREALLOC)
  EXT4_FEATURE_COMPAT_FUNCS(imagic_inodes,	IMAGIC_INODES)
  EXT4_FEATURE_COMPAT_FUNCS(journal,		HAS_JOURNAL)
  EXT4_FEATURE_COMPAT_FUNCS(xattr,		EXT_ATTR)
  EXT4_FEATURE_COMPAT_FUNCS(resize_inode,		RESIZE_INODE)
  EXT4_FEATURE_COMPAT_FUNCS(dir_index,		DIR_INDEX)
  EXT4_FEATURE_COMPAT_FUNCS(sparse_super2,	SPARSE_SUPER2)
  
  EXT4_FEATURE_RO_COMPAT_FUNCS(sparse_super,	SPARSE_SUPER)
  EXT4_FEATURE_RO_COMPAT_FUNCS(large_file,	LARGE_FILE)
  EXT4_FEATURE_RO_COMPAT_FUNCS(btree_dir,		BTREE_DIR)
  EXT4_FEATURE_RO_COMPAT_FUNCS(huge_file,		HUGE_FILE)
  EXT4_FEATURE_RO_COMPAT_FUNCS(gdt_csum,		GDT_CSUM)
  EXT4_FEATURE_RO_COMPAT_FUNCS(dir_nlink,		DIR_NLINK)
  EXT4_FEATURE_RO_COMPAT_FUNCS(extra_isize,	EXTRA_ISIZE)
  EXT4_FEATURE_RO_COMPAT_FUNCS(quota,		QUOTA)
  EXT4_FEATURE_RO_COMPAT_FUNCS(bigalloc,		BIGALLOC)
  EXT4_FEATURE_RO_COMPAT_FUNCS(metadata_csum,	METADATA_CSUM)
  EXT4_FEATURE_RO_COMPAT_FUNCS(readonly,		READONLY)
  EXT4_FEATURE_RO_COMPAT_FUNCS(project,		PROJECT)
  
  EXT4_FEATURE_INCOMPAT_FUNCS(compression,	COMPRESSION)
  EXT4_FEATURE_INCOMPAT_FUNCS(filetype,		FILETYPE)
  EXT4_FEATURE_INCOMPAT_FUNCS(journal_needs_recovery,	RECOVER)
  EXT4_FEATURE_INCOMPAT_FUNCS(journal_dev,	JOURNAL_DEV)
  EXT4_FEATURE_INCOMPAT_FUNCS(meta_bg,		META_BG)
  EXT4_FEATURE_INCOMPAT_FUNCS(extents,		EXTENTS)
  EXT4_FEATURE_INCOMPAT_FUNCS(64bit,		64BIT)
  EXT4_FEATURE_INCOMPAT_FUNCS(mmp,		MMP)
  EXT4_FEATURE_INCOMPAT_FUNCS(flex_bg,		FLEX_BG)
  EXT4_FEATURE_INCOMPAT_FUNCS(ea_inode,		EA_INODE)
  EXT4_FEATURE_INCOMPAT_FUNCS(dirdata,		DIRDATA)
  EXT4_FEATURE_INCOMPAT_FUNCS(csum_seed,		CSUM_SEED)
  EXT4_FEATURE_INCOMPAT_FUNCS(largedir,		LARGEDIR)
  EXT4_FEATURE_INCOMPAT_FUNCS(inline_data,	INLINE_DATA)
  EXT4_FEATURE_INCOMPAT_FUNCS(encrypt,		ENCRYPT)

  #define EXT2_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
  #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
  					 EXT4_FEATURE_INCOMPAT_META_BG)
  #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
  					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
  					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR)
  
  #define EXT3_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR
  #define EXT3_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
  					 EXT4_FEATURE_INCOMPAT_RECOVER| \
  					 EXT4_FEATURE_INCOMPAT_META_BG)
  #define EXT3_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
  					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
  					 EXT4_FEATURE_RO_COMPAT_BTREE_DIR)

  #define EXT4_FEATURE_COMPAT_SUPP	EXT4_FEATURE_COMPAT_EXT_ATTR

  #define EXT4_FEATURE_INCOMPAT_SUPP	(EXT4_FEATURE_INCOMPAT_FILETYPE| \
  					 EXT4_FEATURE_INCOMPAT_RECOVER| \

  					 EXT4_FEATURE_INCOMPAT_META_BG| \

  					 EXT4_FEATURE_INCOMPAT_EXTENTS| \

  					 EXT4_FEATURE_INCOMPAT_64BIT| \

  					 EXT4_FEATURE_INCOMPAT_FLEX_BG| \

  					 EXT4_FEATURE_INCOMPAT_EA_INODE| \

  					 EXT4_FEATURE_INCOMPAT_MMP | \
  					 EXT4_FEATURE_INCOMPAT_INLINE_DATA | \

  					 EXT4_FEATURE_INCOMPAT_ENCRYPT | \

  					 EXT4_FEATURE_INCOMPAT_CSUM_SEED | \
  					 EXT4_FEATURE_INCOMPAT_LARGEDIR)

  #define EXT4_FEATURE_RO_COMPAT_SUPP	(EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
  					 EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \

  					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \

  					 EXT4_FEATURE_RO_COMPAT_DIR_NLINK | \

  					 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE | \