/*
 *  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/blockgroup_lock.h>
#include <linux/percpu_counter.h>
#include <linux/ratelimit.h>
#include <crypto/hash.h>
#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
#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)))

/* 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         0x204380FF /* User modifiable flags */

#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

/* Encryption algorithms */
#define EXT4_ENCRYPTION_MODE_INVALID            0
#define EXT4_ENCRYPTION_MODE_AES_256_XTS        1
#define EXT4_ENCRYPTION_MODE_AES_256_GCM        2
#define EXT4_ENCRYPTION_MODE_AES_256_CBC        3
#define EXT4_ENCRYPTION_MODE_AES_256_CTS        4

#include "ext4_crypto.h"

/*
 * 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  _IOR('f', 19, struct ext4_encryption_policy)
#define EXT4_IOC_GET_ENCRYPTION_PWSALT  _IOW('f', 20, __u8[16])
#define EXT4_IOC_GET_ENCRYPTION_POLICY  _IOW('f', 21, struct ext4_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

#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

/*
 * 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 LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
                /* Handle legacy encoding of pre-1970 dates with epoch
                 * bits 1,1.  We assume that by kernel version 4.20,
                 * everyone will have run fsck over the affected
                 * filesystems to correct the problem.  (This
                 * backwards compatibility may be removed before this
                 * time, 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 ued 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, these refer to clusters rather than blocks */
        unsigned int i_reserved_data_blocks;
        unsigned int i_reserved_meta_blocks;
        unsigned int i_allocated_meta_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;

#ifdef CONFIG_EXT4_FS_ENCRYPTION
        /* Encryption params */
        struct ext4_crypt_info *i_crypt_info;
#endif
        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_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                0x80000 /* Some quota option set */
#define EXT4_MOUNT_USRQUOTA             0x100000 /* "old" user quota */
#define EXT4_MOUNT_GRPQUOTA             0x200000 /* "old" group quota */
#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_resize_flags;           /* Flags indicating if there
                                                   is a resizer */
        unsigned long s_commit_interval;
        u32 s_max_batch_time;
        u32 s_min_batch_time;
        struct block_device *journal_bdev;
#ifdef CONFIG_QUOTA
        char *s_qf_names[EXT4_MAXQUOTAS];       /* Names of quota files with journalled quota */
        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;

        /* 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_mb_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;
};

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 struct timespec ext4_current_time(struct inode *inode)
{
        return (inode->i_sb->s_time_gran < NSEC_PER_SEC) ?
                current_fs_time(inode->i_sb) : CURRENT_TIME_SEC;
}

static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
{
        return ino == EXT4_ROOT_INO ||
                ino == EXT4_USR_QUOTA_INO ||
                ino == EXT4_GRP_QUOTA_INO ||
                ino == EXT4_BOOT_LOADER_INO ||
                ino == EXT4_JOURNAL_INO ||
                ino == EXT4_RESIZE_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 */
};

#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
 */
static inline int ext4_encrypted_inode(struct inode *inode)
{
#ifdef CONFIG_EXT4_FS_ENCRYPTION
        return ext4_test_inode_flag(inode, EXT4_INODE_ENCRYPT);
#else
        return 0;
#endif
}

#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
 */

/* Use the ext4_{has,set,clear}_feature_* helpers; these will be removed */
#define EXT4_HAS_COMPAT_FEATURE(sb,mask)                        \
        ((EXT4_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask)) != 0)
#define EXT4_HAS_RO_COMPAT_FEATURE(sb,mask)                     \
        ((EXT4_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask)) != 0)
#define EXT4_HAS_INCOMPAT_FEATURE(sb,mask)                      \
        ((EXT4_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask)) != 0)
#define EXT4_SET_COMPAT_FEATURE(sb,mask)                        \
        EXT4_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
#define EXT4_SET_RO_COMPAT_FEATURE(sb,mask)                     \
        EXT4_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
#define EXT4_SET_INCOMPAT_FEATURE(sb,mask)                      \
        EXT4_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
#define EXT4_CLEAR_COMPAT_FEATURE(sb,mask)                      \
        EXT4_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
#define EXT4_CLEAR_RO_COMPAT_FEATURE(sb,mask)                   \
        EXT4_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
#define EXT4_CLEAR_INCOMPAT_FEATURE(sb,mask)                    \
        EXT4_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)

#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_MMP | \
                                         EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
                                         EXT4_FEATURE_INCOMPAT_ENCRYPT | \
                                         EXT4_FEATURE_INCOMPAT_CSUM_SEED)
#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 | \
                                         EXT4_FEATURE_RO_COMPAT_BTREE_DIR |\
                                         EXT4_FEATURE_RO_COMPAT_HUGE_FILE |\
                                         EXT4_FEATURE_RO_COMPAT_BIGALLOC |\
                                         EXT4_FEATURE_RO_COMPAT_METADATA_CSUM|\
                                         EXT4_FEATURE_RO_COMPAT_QUOTA |\
                                         EXT4_FEATURE_RO_COMPAT_PROJECT)

#define EXTN_FEATURE_FUNCS(ver) \
static inline bool ext4_has_unknown_ext##ver##_compat_features(struct super_block *sb) \
{ \
        return ((EXT4_SB(sb)->s_es->s_feature_compat & \
                cpu_to_le32(~EXT##ver##_FEATURE_COMPAT_SUPP)) != 0); \
} \
static inline bool ext4_has_unknown_ext##ver##_ro_compat_features(struct super_block *sb) \
{ \
        return ((EXT4_SB(sb)->s_es->s_feature_ro_compat & \
                cpu_to_le32(~EXT##ver##_FEATURE_RO_COMPAT_SUPP)) != 0); \
} \
static inline bool ext4_has_unknown_ext##ver##_incompat_features(struct super_block *sb) \
{ \
        return ((EXT4_SB(sb)->s_es->s_feature_incompat & \
                cpu_to_le32(~EXT##ver##_FEATURE_INCOMPAT_SUPP)) != 0); \
}

EXTN_FEATURE_FUNCS(2)
EXTN_FEATURE_FUNCS(3)
EXTN_FEATURE_FUNCS(4)

static inline bool ext4_has_compat_features(struct super_block *sb)
{
        return (EXT4_SB(sb)->s_es->s_feature_compat != 0);
}
static inline bool ext4_has_ro_compat_features(struct super_block *sb)
{
        return (EXT4_SB(sb)->s_es->s_feature_ro_compat != 0);
}
static inline bool ext4_has_incompat_features(struct super_block *sb)
{
        return (EXT4_SB(sb)->s_es->s_feature_incompat != 0);
}

/*
 * Default values for user and/or group using reserved blocks
 */
#define EXT4_DEF_RESUID         0
#define EXT4_DEF_RESGID         0

/*
 * Default project ID
 */
#define EXT4_DEF_PROJID         0

#define EXT4_DEF_INODE_READAHEAD_BLKS   32

/*
 * Default mount options
 */
#define EXT4_DEFM_DEBUG         0x0001
#define EXT4_DEFM_BSDGROUPS     0x0002
#define EXT4_DEFM_XATTR_USER    0x0004
#define EXT4_DEFM_ACL           0x0008
#define EXT4_DEFM_UID16         0x0010
#define EXT4_DEFM_JMODE         0x0060
#define EXT4_DEFM_JMODE_DATA    0x0020
#define EXT4_DEFM_JMODE_ORDERED 0x0040
#define EXT4_DEFM_JMODE_WBACK   0x0060
#define EXT4_DEFM_NOBARRIER     0x0100
#define EXT4_DEFM_BLOCK_VALIDITY 0x0200
#define EXT4_DEFM_DISCARD       0x0400
#define EXT4_DEFM_NODELALLOC    0x0800

/*
 * Default journal batch times
 */
#define EXT4_DEF_MIN_BATCH_TIME 0
#define EXT4_DEF_MAX_BATCH_TIME 15000 /* 15ms */

/*
 * Minimum number of groups in a flexgroup before we separate out
 * directories into the first block group of a flexgroup
 */
#define EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME 4

/*
 * Structure of a directory entry
 */
#define EXT4_NAME_LEN 255

struct ext4_dir_entry {
        __le32  inode;                  /* Inode number */
        __le16  rec_len;                /* Directory entry length */
        __le16  name_len;               /* Name length */
        char    name[EXT4_NAME_LEN];    /* File name */
};

/*
 * The new version of the directory entry.  Since EXT4 structures are
 * stored in intel byte order, and the name_len field could never be
 * bigger than 255 chars, it's safe to reclaim the extra byte for the
 * file_type field.
 */
struct ext4_dir_entry_2 {
        __le32  inode;                  /* Inode number */
        __le16  rec_len;                /* Directory entry length */
        __u8    name_len;               /* Name length */
        __u8    file_type;
        char    name[EXT4_NAME_LEN];    /* File name */
};

/*
 * This is a bogus directory entry at the end of each leaf block that
 * records checksums.
 */
struct ext4_dir_entry_tail {
        __le32  det_reserved_zero1;     /* Pretend to be unused */
        __le16  det_rec_len;            /* 12 */
        __u8    det_reserved_zero2;     /* Zero name length */
        __u8    det_reserved_ft;        /* 0xDE, fake file type */
        __le32  det_checksum;           /* crc32c(uuid+inum+dirblock) */
};

#define EXT4_DIRENT_TAIL(block, blocksize) \
        ((struct ext4_dir_entry_tail *)(((void *)(block)) + \
                                        ((blocksize) - \
                                         sizeof(struct ext4_dir_entry_tail))))

/*
 * Ext4 directory file types.  Only the low 3 bits are used.  The
 * other bits are reserved for now.
 */
#define EXT4_FT_UNKNOWN         0
#define EXT4_FT_REG_FILE        1
#define EXT4_FT_DIR             2
#define EXT4_FT_CHRDEV          3
#define EXT4_FT_BLKDEV          4
#define EXT4_FT_FIFO            5
#define EXT4_FT_SOCK            6
#define EXT4_FT_SYMLINK         7

#define EXT4_FT_MAX             8

#define EXT4_FT_DIR_CSUM        0xDE

/*
 * EXT4_DIR_PAD defines the directory entries boundaries
 *
 * NOTE: It must be a multiple of 4
 */
#define EXT4_DIR_PAD                    4
#define EXT4_DIR_ROUND                  (EXT4_DIR_PAD - 1)
#define EXT4_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT4_DIR_ROUND) & \
                                         ~EXT4_DIR_ROUND)
#define EXT4_MAX_REC_LEN                ((1<<16)-1)

/*
 * If we ever get support for fs block sizes > page_size, we'll need
 * to remove the #if statements in the next two functions...
 */
static inline unsigned int
ext4_rec_len_from_disk(__le16 dlen, unsigned blocksize)
{
        unsigned len = le16_to_cpu(dlen);

#if (PAGE_SIZE >= 65536)
        if (len == EXT4_MAX_REC_LEN || len == 0)
                return blocksize;
        return (len & 65532) | ((len & 3) << 16);
#else
        return len;
#endif
}

static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize)
{
        if ((len > blocksize) || (blocksize > (1 << 18)) || (len & 3))
                BUG();
#if (PAGE_SIZE >= 65536)
        if (len < 65536)
                return cpu_to_le16(len);
        if (len == blocksize) {
                if (blocksize == 65536)
                        return cpu_to_le16(EXT4_MAX_REC_LEN);
                else
                        return cpu_to_le16(0);
        }
        return cpu_to_le16((len & 65532) | ((len >> 16) & 3));
#else
        return cpu_to_le16(len);
#endif
}

/*
 * Hash Tree Directory indexing
 * (c) Daniel Phillips, 2001
 */

#define is_dx(dir) (ext4_has_feature_dir_index((dir)->i_sb) && \
                    ext4_test_inode_flag((dir), EXT4_INODE_INDEX))
#define EXT4_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT4_LINK_MAX)
#define EXT4_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)

/* Legal values for the dx_root hash_version field: */

#define DX_HASH_LEGACY          0
#define DX_HASH_HALF_MD4        1
#define DX_HASH_TEA             2
#define DX_HASH_LEGACY_UNSIGNED 3
#define DX_HASH_HALF_MD4_UNSIGNED       4
#define DX_HASH_TEA_UNSIGNED            5

static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc,
                              const void *address, unsigned int length)
{
        struct {
                struct shash_desc shash;
                char ctx[4];
        } desc;
        int err;

        BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver)!=sizeof(desc.ctx));

        desc.shash.tfm = sbi->s_chksum_driver;
        desc.shash.flags = 0;
        *(u32 *)desc.ctx = crc;

        err = crypto_shash_update(&desc.shash, address, length);
        BUG_ON(err);

        return *(u32 *)desc.ctx;
}

#ifdef __KERNEL__

/* hash info structure used by the directory hash */
struct dx_hash_info
{
        u32             hash;
        u32             minor_hash;
        int             hash_version;
        u32             *seed;
};


/* 32 and 64 bit signed EOF for dx directories */
#define EXT4_HTREE_EOF_32BIT   ((1UL  << (32 - 1)) - 1)
#define EXT4_HTREE_EOF_64BIT   ((1ULL << (64 - 1)) - 1)


/*
 * Control parameters used by ext4_htree_next_block
 */
#define HASH_NB_ALWAYS          1

struct ext4_filename {
        const struct qstr *usr_fname;
        struct ext4_str disk_name;
        struct dx_hash_info hinfo;
#ifdef CONFIG_EXT4_FS_ENCRYPTION
        struct ext4_str crypto_buf;
#endif
};

#define fname_name(p) ((p)->disk_name.name)
#define fname_len(p)  ((p)->disk_name.len)

/*
 * Describe an inode's exact location on disk and in memory
 */
struct ext4_iloc
{
        struct buffer_head *bh;
        unsigned long offset;
        ext4_group_t block_group;
};

static inline struct ext4_inode *ext4_raw_inode(struct ext4_iloc *iloc)
{
        return (struct ext4_inode *) (iloc->bh->b_data + iloc->offset);
}

/*
 * This structure is stuffed into the struct file's private_data field
 * for directories.  It is where we put information so that we can do
 * readdir operations in hash tree order.
 */
struct dir_private_info {
        struct rb_root  root;
        struct rb_node  *curr_node;
        struct fname    *extra_fname;
        loff_t          last_pos;
        __u32           curr_hash;
        __u32           curr_minor_hash;
        __u32           next_hash;
};

/* calculate the first block number of the group */
static inline ext4_fsblk_t
ext4_group_first_block_no(struct super_block *sb, ext4_group_t group_no)
{
        return group_no * (ext4_fsblk_t)EXT4_BLOCKS_PER_GROUP(sb) +
                le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
}

/*
 * Special error return code only used by dx_probe() and its callers.
 */
#define ERR_BAD_DX_DIR  (-(MAX_ERRNO - 1))

/*
 * Timeout and state flag for lazy initialization inode thread.
 */
#define EXT4_DEF_LI_WAIT_MULT                   10
#define EXT4_DEF_LI_MAX_START_DELAY             5
#define EXT4_LAZYINIT_QUIT                      0x0001
#define EXT4_LAZYINIT_RUNNING                   0x0002

/*
 * Lazy inode table initialization info
 */
struct ext4_lazy_init {
        unsigned long           li_state;
        struct list_head        li_request_list;
        struct mutex            li_list_mtx;
};

struct ext4_li_request {
        struct super_block      *lr_super;
        struct ext4_sb_info     *lr_sbi;
        ext4_group_t            lr_next_group;
        struct list_head        lr_request;
        unsigned long           lr_next_sched;
        unsigned long           lr_timeout;
};

struct ext4_features {
        struct kobject f_kobj;
        struct completion f_kobj_unregister;
};

/*
 * This structure will be used for multiple mount protection. It will be
 * written into the block number saved in the s_mmp_block field in the
 * superblock. Programs that check MMP should assume that if
 * SEQ_FSCK (or any unknown code above SEQ_MAX) is present then it is NOT safe
 * to use the filesystem, regardless of how old the timestamp is.
 */
#define EXT4_MMP_MAGIC     0x004D4D50U /* ASCII for MMP */
#define EXT4_MMP_SEQ_CLEAN 0xFF4D4D50U /* mmp_seq value for clean unmount */
#define EXT4_MMP_SEQ_FSCK  0xE24D4D50U /* mmp_seq value when being fscked */
#define EXT4_MMP_SEQ_MAX   0xE24D4D4FU /* maximum valid mmp_seq value */

struct mmp_struct {
        __le32  mmp_magic;              /* Magic number for MMP */
        __le32  mmp_seq;                /* Sequence no. updated periodically */

        /*
         * mmp_time, mmp_nodename & mmp_bdevname are only used for information
         * purposes and do not affect the correctness of the algorithm
         */
        __le64  mmp_time;               /* Time last updated */
        char    mmp_nodename[64];       /* Node which last updated MMP block */
        char    mmp_bdevname[32];       /* Bdev which last updated MMP block */

        /*
         * mmp_check_interval is used to verify if the MMP block has been
         * updated on the block device. The value is updated based on the
         * maximum time to write the MMP block during an update cycle.
         */
        __le16  mmp_check_interval;

        __le16  mmp_pad1;
        __le32  mmp_pad2[226];
        __le32  mmp_checksum;           /* crc32c(uuid+mmp_block) */
};

/* arguments passed to the mmp thread */
struct mmpd_data {
        struct buffer_head *bh; /* bh from initial read_mmp_block() */
        struct super_block *sb;  /* super block of the fs */
};

/*
 * Check interval multiplier
 * The MMP block is written every update interval and initially checked every
 * update interval x the multiplier (the value is then adapted based on the
 * write latency). The reason is that writes can be delayed under load and we
 * don't want readers to incorrectly assume that the filesystem is no longer
 * in use.
 */
#define EXT4_MMP_CHECK_MULT             2UL

/*
 * Minimum interval for MMP checking in seconds.
 */
#define EXT4_MMP_MIN_CHECK_INTERVAL     5UL

/*
 * Maximum interval for MMP checking in seconds.
 */
#define EXT4_MMP_MAX_CHECK_INTERVAL     300UL

/*
 * Function prototypes
 */

/*
 * Ok, these declarations are also in <linux/kernel.h> but none of the
 * ext4 source programs needs to include it so they are duplicated here.
 */
# define NORET_TYPE     /**/
# define ATTRIB_NORET   __attribute__((noreturn))
# define NORET_AND      noreturn,

/* bitmap.c */
extern unsigned int ext4_count_free(char *bitmap, unsigned numchars);
void ext4_inode_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
                                struct ext4_group_desc *gdp,
                                struct buffer_head *bh, int sz);
int ext4_inode_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
                                  struct ext4_group_desc *gdp,
                                  struct buffer_head *bh, int sz);
void ext4_block_bitmap_csum_set(struct super_block *sb, ext4_group_t group,
                                struct ext4_group_desc *gdp,
                                struct buffer_head *bh);
int ext4_block_bitmap_csum_verify(struct super_block *sb, ext4_group_t group,
                                  struct ext4_group_desc *gdp,
                                  struct buffer_head *bh);

/* balloc.c */
extern void ext4_get_group_no_and_offset(struct super_block *sb,
                                         ext4_fsblk_t blocknr,
                                         ext4_group_t *blockgrpp,
                                         ext4_grpblk_t *offsetp);
extern ext4_group_t ext4_get_group_number(struct super_block *sb,
                                          ext4_fsblk_t block);

extern unsigned int ext4_block_group(struct super_block *sb,
                        ext4_fsblk_t blocknr);
extern ext4_grpblk_t ext4_block_group_offset(struct super_block *sb,
                        ext4_fsblk_t blocknr);
extern int ext4_bg_has_super(struct super_block *sb, ext4_group_t group);
extern unsigned long ext4_bg_num_gdb(struct super_block *sb,
                        ext4_group_t group);
extern ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
                                         ext4_fsblk_t goal,
                                         unsigned int flags,
                                         unsigned long *count,
                                         int *errp);
extern int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
                                    s64 nclusters, unsigned int flags);
extern ext4_fsblk_t ext4_count_free_clusters(struct super_block *);
extern void ext4_check_blocks_bitmap(struct super_block *);
extern struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
                                                    ext4_group_t block_group,
                                                    struct buffer_head ** bh);
extern int ext4_should_retry_alloc(struct super_block *sb, int *retries);

extern struct buffer_head *ext4_read_block_bitmap_nowait(struct super_block *sb,
                                                ext4_group_t block_group);
extern int ext4_wait_block_bitmap(struct super_block *sb,
                                  ext4_group_t block_group,
                                  struct buffer_head *bh);
extern struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
                                                  ext4_group_t block_group);
extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
                                              ext4_group_t block_group,
                                              struct ext4_group_desc *gdp);
ext4_fsblk_t ext4_inode_to_goal_block(struct inode *);

/* crypto_policy.c */
int ext4_is_child_context_consistent_with_parent(struct inode *parent,
                                                 struct inode *child);
int ext4_inherit_context(struct inode *parent, struct inode *child);
void ext4_to_hex(char *dst, char *src, size_t src_size);
int ext4_process_policy(const struct ext4_encryption_policy *policy,
                        struct inode *inode);
int ext4_get_policy(struct inode *inode,
                    struct ext4_encryption_policy *policy);

/* crypto.c */
extern struct kmem_cache *ext4_crypt_info_cachep;
bool ext4_valid_contents_enc_mode(uint32_t mode);
uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size);
extern struct workqueue_struct *ext4_read_workqueue;
struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode,
                                            gfp_t gfp_flags);
void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx);
void ext4_restore_control_page(struct page *data_page);
struct page *ext4_encrypt(struct inode *inode,
                          struct page *plaintext_page,
                          gfp_t gfp_flags);
int ext4_decrypt(struct page *page);
int ext4_encrypted_zeroout(struct inode *inode, ext4_lblk_t lblk,
                           ext4_fsblk_t pblk, ext4_lblk_t len);
extern const struct dentry_operations ext4_encrypted_d_ops;

#ifdef CONFIG_EXT4_FS_ENCRYPTION
int ext4_init_crypto(void);
void ext4_exit_crypto(void);
static inline int ext4_sb_has_crypto(struct super_block *sb)
{
        return ext4_has_feature_encrypt(sb);
}
#else
static inline int ext4_init_crypto(void) { return 0; }
static inline void ext4_exit_crypto(void) { }
static inline int ext4_sb_has_crypto(struct super_block *sb)
{
        return 0;
}
#endif

/* crypto_fname.c */
bool ext4_valid_filenames_enc_mode(uint32_t mode);
u32 ext4_fname_crypto_round_up(u32 size, u32 blksize);
unsigned ext4_fname_encrypted_size(struct inode *inode, u32 ilen);
int ext4_fname_crypto_alloc_buffer(struct inode *inode,
                                   u32 ilen, struct ext4_str *crypto_str);
int _ext4_fname_disk_to_usr(struct inode *inode,
                            struct dx_hash_info *hinfo,
                            const struct ext4_str *iname,
                            struct ext4_str *oname);
int ext4_fname_disk_to_usr(struct inode *inode,
                           struct dx_hash_info *hinfo,
                           const struct ext4_dir_entry_2 *de,
                           struct ext4_str *oname);
int ext4_fname_usr_to_disk(struct inode *inode,
                           const struct qstr *iname,
                           struct ext4_str *oname);
#ifdef CONFIG_EXT4_FS_ENCRYPTION
void ext4_fname_crypto_free_buffer(struct ext4_str *crypto_str);
int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
                              int lookup, struct ext4_filename *fname);
void ext4_fname_free_filename(struct ext4_filename *fname);
#else
static inline
int ext4_setup_fname_crypto(struct inode *inode)
{
        return 0;
}
static inline void ext4_fname_crypto_free_buffer(struct ext4_str *p) { }
static inline int ext4_fname_setup_filename(struct inode *dir,
                                     const struct qstr *iname,
                                     int lookup, struct ext4_filename *fname)
{
        fname->usr_fname = iname;
        fname->disk_name.name = (unsigned char *) iname->name;
        fname->disk_name.len = iname->len;
        return 0;
}
static inline void ext4_fname_free_filename(struct ext4_filename *fname) { }
#endif


/* crypto_key.c */
void ext4_free_crypt_info(struct ext4_crypt_info *ci);
void ext4_free_encryption_info(struct inode *inode, struct ext4_crypt_info *ci);
int _ext4_get_encryption_info(struct inode *inode);

#ifdef CONFIG_EXT4_FS_ENCRYPTION
int ext4_has_encryption_key(struct inode *inode);

static inline int ext4_get_encryption_info(struct inode *inode)
{
        struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info;

        if (!ci ||
            (ci->ci_keyring_key &&
             (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
                                           (1 << KEY_FLAG_REVOKED) |
                                           (1 << KEY_FLAG_DEAD)))))
                return _ext4_get_encryption_info(inode);
        return 0;
}

static inline struct ext4_crypt_info *ext4_encryption_info(struct inode *inode)
{
        return EXT4_I(inode)->i_crypt_info;
}

#else
static inline int ext4_has_encryption_key(struct inode *inode)
{
        return 0;
}
static inline int ext4_get_encryption_info(struct inode *inode)
{
        return 0;
}
static inline struct ext4_crypt_info *ext4_encryption_info(struct inode *inode)
{
        return NULL;
}
#endif


/* dir.c */
extern int __ext4_check_dir_entry(const char *, unsigned int, struct inode *,
                                  struct file *,
                                  struct ext4_dir_entry_2 *,
                                  struct buffer_head *, char *, int,
                                  unsigned int);
#define ext4_check_dir_entry(dir, filp, de, bh, buf, size, offset)      \
        unlikely(__ext4_check_dir_entry(__func__, __LINE__, (dir), (filp), \
                                        (de), (bh), (buf), (size), (offset)))
extern int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
                                __u32 minor_hash,
                                struct ext4_dir_entry_2 *dirent,
                                struct ext4_str *ent_name);
extern void ext4_htree_free_dir_info(struct dir_private_info *p);
extern int ext4_find_dest_de(struct inode *dir, struct inode *inode,
                             struct buffer_head *bh,
                             void *buf, int buf_size,
                             struct ext4_filename *fname,
                             struct ext4_dir_entry_2 **dest_de);
int ext4_insert_dentry(struct inode *dir,
                       struct inode *inode,
                       struct ext4_dir_entry_2 *de,
                       int buf_size,
                       struct ext4_filename *fname);
static inline void ext4_update_dx_flag(struct inode *inode)
{
        if (!ext4_has_feature_dir_index(inode->i_sb))
                ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
}
static unsigned char ext4_filetype_table[] = {
        DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
};

static inline  unsigned char get_dtype(struct super_block *sb, int filetype)
{
        if (!ext4_has_feature_filetype(sb) || filetype >= EXT4_FT_MAX)
                return DT_UNKNOWN;

        return ext4_filetype_table[filetype];
}
extern int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
                             void *buf, int buf_size);

/* fsync.c */
extern int ext4_sync_file(struct file *, loff_t, loff_t, int);

/* hash.c */
extern int ext4fs_dirhash(const char *name, int len, struct
                          dx_hash_info *hinfo);

/* ialloc.c */
extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
                                      const struct qstr *qstr, __u32 goal,
                                      uid_t *owner, int handle_type,
                                      unsigned int line_no, int nblocks);

#define ext4_new_inode(handle, dir, mode, qstr, goal, owner) \
        __ext4_new_inode((handle), (dir), (mode), (qstr), (goal), (owner), \
                         0, 0, 0)
#define ext4_new_inode_start_handle(dir, mode, qstr, goal, owner, \
                                    type, nblocks)                  \
        __ext4_new_inode(NULL, (dir), (mode), (qstr), (goal), (owner), \
                         (type), __LINE__, (nblocks))


extern void ext4_free_inode(handle_t *, struct inode *);
extern struct inode * ext4_orphan_get(struct super_block *, unsigned long);
extern unsigned long ext4_count_free_inodes(struct super_block *);
extern unsigned long ext4_count_dirs(struct super_block *);
extern void ext4_check_inodes_bitmap(struct super_block *);
extern void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap);
extern int ext4_init_inode_table(struct super_block *sb,
                                 ext4_group_t group, int barrier);
extern void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate);

/* mballoc.c */
extern const struct file_operations ext4_seq_mb_groups_fops;
extern long ext4_mb_stats;
extern long ext4_mb_max_to_scan;
extern int ext4_mb_init(struct super_block *);
extern int ext4_mb_release(struct super_block *);
extern ext4_fsblk_t ext4_mb_new_blocks(handle_t *,
                                struct ext4_allocation_request *, int *);
extern int ext4_mb_reserve_blocks(struct super_block *, int);
extern void ext4_discard_preallocations(struct inode *);
extern int __init ext4_init_mballoc(void);
extern void ext4_exit_mballoc(void);
extern void ext4_free_blocks(handle_t *handle, struct inode *inode,
                             struct buffer_head *bh, ext4_fsblk_t block,
                             unsigned long count, int flags);
extern int ext4_mb_alloc_groupinfo(struct super_block *sb,
                                   ext4_group_t ngroups);
extern int ext4_mb_add_groupinfo(struct super_block *sb,
                ext4_group_t i, struct ext4_group_desc *desc);
extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
                                ext4_fsblk_t block, unsigned long count);
extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);

/* inode.c */
int ext4_inode_is_fast_symlink(struct inode *inode);
struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
                             struct buffer_head *bh_result, int create);
int ext4_dax_get_block(struct inode *inode, sector_t iblock,
                       struct buffer_head *bh_result, int create);
int ext4_get_block(struct inode *inode, sector_t iblock,
                   struct buffer_head *bh_result, int create);
int ext4_dio_get_block(struct inode *inode, sector_t iblock,
                       struct buffer_head *bh_result, int create);
int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                           struct buffer_head *bh, int create);
int ext4_walk_page_buffers(handle_t *handle,
                           struct buffer_head *head,
                           unsigned from,
                           unsigned to,
                           int *partial,
                           int (*fn)(handle_t *handle,
                                     struct buffer_head *bh));
int do_journal_get_write_access(handle_t *handle,
                                struct buffer_head *bh);
#define FALL_BACK_TO_NONDELALLOC 1
#define CONVERT_INLINE_DATA      2

extern struct inode *ext4_iget(struct super_block *, unsigned long);
extern struct inode *ext4_iget_normal(struct super_block *, unsigned long);
extern int  ext4_write_inode(struct inode *, struct writeback_control *);
extern int  ext4_setattr(struct dentry *, struct iattr *);
extern int  ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
                                struct kstat *stat);
extern void ext4_evict_inode(struct inode *);
extern void ext4_clear_inode(struct inode *);
extern int  ext4_sync_inode(handle_t *, struct inode *);
extern void ext4_dirty_inode(struct inode *, int);
extern int ext4_change_inode_journal_flag(struct inode *, int);
extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
extern int ext4_inode_attach_jinode(struct inode *inode);
extern int ext4_can_truncate(struct inode *inode);
extern void ext4_truncate(struct inode *);
extern int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length);
extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
extern void ext4_set_inode_flags(struct inode *);
extern void ext4_get_inode_flags(struct ext4_inode_info *);
extern int ext4_alloc_da_blocks(struct inode *inode);
extern void ext4_set_aops(struct inode *inode);
extern int ext4_writepage_trans_blocks(struct inode *);
extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
extern int ext4_zero_partial_blocks(handle_t *handle, struct inode *inode,
                             loff_t lstart, loff_t lend);
extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
extern int ext4_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf);
extern qsize_t *ext4_get_reserved_space(struct inode *inode);
extern int ext4_get_projid(struct inode *inode, kprojid_t *projid);
extern void ext4_da_update_reserve_space(struct inode *inode,
                                        int used, int quota_claim);
extern int ext4_issue_zeroout(struct inode *inode, ext4_lblk_t lblk,
                              ext4_fsblk_t pblk, ext4_lblk_t len);
extern int ext4_get_next_extent(struct inode *inode, ext4_lblk_t lblk,
                                unsigned int map_len,
                                struct extent_status *result);

/* indirect.c */
extern int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
                                struct ext4_map_blocks *map, int flags);
extern int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock);
extern int ext4_ind_trans_blocks(struct inode *inode, int nrblocks);
extern void ext4_ind_truncate(handle_t *, struct inode *inode);
extern int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
                                 ext4_lblk_t start, ext4_lblk_t end);

/* ioctl.c */
extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);

/* migrate.c */
extern int ext4_ext_migrate(struct inode *);
extern int ext4_ind_migrate(struct inode *inode);

/* namei.c */
extern int ext4_dirent_csum_verify(struct inode *inode,
                                   struct ext4_dir_entry *dirent);
extern int ext4_orphan_add(handle_t *, struct inode *);
extern int ext4_orphan_del(handle_t *, struct inode *);
extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
                                __u32 start_minor_hash, __u32 *next_hash);
extern int ext4_search_dir(struct buffer_head *bh,
                           char *search_buf,
                           int buf_size,
                           struct inode *dir,
                           struct ext4_filename *fname,
                           const struct qstr *d_name,
                           unsigned int offset,
                           struct ext4_dir_entry_2 **res_dir);
extern int ext4_generic_delete_entry(handle_t *handle,
                                     struct inode *dir,
                                     struct ext4_dir_entry_2 *de_del,
                                     struct buffer_head *bh,
                                     void *entry_buf,
                                     int buf_size,
                                     int csum_size);
extern int ext4_empty_dir(struct inode *inode);

/* resize.c */
extern int ext4_group_add(struct super_block *sb,
                                struct ext4_new_group_data *input);
extern int ext4_group_extend(struct super_block *sb,
                                struct ext4_super_block *es,
                                ext4_fsblk_t n_blocks_count);
extern int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count);

/* super.c */
extern int ext4_seq_options_show(struct seq_file *seq, void *offset);
extern int ext4_calculate_overhead(struct super_block *sb);
extern void ext4_superblock_csum_set(struct super_block *sb);
extern void *ext4_kvmalloc(size_t size, gfp_t flags);
extern void *ext4_kvzalloc(size_t size, gfp_t flags);
extern int ext4_alloc_flex_bg_array(struct super_block *sb,
                                    ext4_group_t ngroup);
extern const char *ext4_decode_error(struct super_block *sb, int errno,
                                     char nbuf[16]);

extern __printf(4, 5)
void __ext4_error(struct super_block *, const char *, unsigned int,
                  const char *, ...);
extern __printf(5, 6)
void __ext4_error_inode(struct inode *, const char *, unsigned int, ext4_fsblk_t,
                      const char *, ...);
extern __printf(5, 6)
void __ext4_error_file(struct file *, const char *, unsigned int, ext4_fsblk_t,
                     const char *, ...);
extern void __ext4_std_error(struct super_block *, const char *,
                             unsigned int, int);
extern __printf(4, 5)
void __ext4_abort(struct super_block *, const char *, unsigned int,
                  const char *, ...);
extern __printf(4, 5)
void __ext4_warning(struct super_block *, const char *, unsigned int,
                    const char *, ...);
extern __printf(4, 5)
void __ext4_warning_inode(const struct inode *inode, const char *function,
                          unsigned int line, const char *fmt, ...);
extern __printf(3, 4)
void __ext4_msg(struct super_block *, const char *, const char *, ...);
extern void __dump_mmp_msg(struct super_block *, struct mmp_struct *mmp,
                           const char *, unsigned int, const char *);
extern __printf(7, 8)
void __ext4_grp_locked_error(const char *, unsigned int,
                             struct super_block *, ext4_group_t,
                             unsigned long, ext4_fsblk_t,
                             const char *, ...);

#define EXT4_ERROR_INODE(inode, fmt, a...) \
        ext4_error_inode((inode), __func__, __LINE__, 0, (fmt), ## a)

#define EXT4_ERROR_INODE_BLOCK(inode, block, fmt, a...)                 \
        ext4_error_inode((inode), __func__, __LINE__, (block), (fmt), ## a)

#define EXT4_ERROR_FILE(file, block, fmt, a...)                         \
        ext4_error_file((file), __func__, __LINE__, (block), (fmt), ## a)

#ifdef CONFIG_PRINTK

#define ext4_error_inode(inode, func, line, block, fmt, ...)            \
        __ext4_error_inode(inode, func, line, block, fmt, ##__VA_ARGS__)
#define ext4_error_file(file, func, line, block, fmt, ...)              \
        __ext4_error_file(file, func, line, block, fmt, ##__VA_ARGS__)
#define ext4_error(sb, fmt, ...)                                        \
        __ext4_error(sb, __func__, __LINE__, fmt, ##__VA_ARGS__)
#define ext4_abort(sb, fmt, ...)                                        \
        __ext4_abort(sb, __func__, __LINE__, fmt, ##__VA_ARGS__)
#define ext4_warning(sb, fmt, ...)                                      \
        __ext4_warning(sb, __func__, __LINE__, fmt, ##__VA_ARGS__)
#define ext4_warning_inode(inode, fmt, ...)                             \
        __ext4_warning_inode(inode, __func__, __LINE__, fmt, ##__VA_ARGS__)
#define ext4_msg(sb, level, fmt, ...)                           \
        __ext4_msg(sb, level, fmt, ##__VA_ARGS__)
#define dump_mmp_msg(sb, mmp, msg)                                      \
        __dump_mmp_msg(sb, mmp, __func__, __LINE__, msg)
#define ext4_grp_locked_error(sb, grp, ino, block, fmt, ...)            \
        __ext4_grp_locked_error(__func__, __LINE__, sb, grp, ino, block, \
                                fmt, ##__VA_ARGS__)

#else

#define ext4_error_inode(inode, func, line, block, fmt, ...)            \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_error_inode(inode, "", 0, block, " ");                   \
} while (0)
#define ext4_error_file(file, func, line, block, fmt, ...)              \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_error_file(file, "", 0, block, " ");                     \
} while (0)
#define ext4_error(sb, fmt, ...)                                        \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_error(sb, "", 0, " ");                                   \
} while (0)
#define ext4_abort(sb, fmt, ...)                                        \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_abort(sb, "", 0, " ");                                   \
} while (0)
#define ext4_warning(sb, fmt, ...)                                      \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_warning(sb, "", 0, " ");                                 \
} while (0)
#define ext4_warning_inode(inode, fmt, ...)                             \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_warning_inode(inode, "", 0, " ");                        \
} while (0)
#define ext4_msg(sb, level, fmt, ...)                                   \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                                  \
        __ext4_msg(sb, "", " ");                                        \
} while (0)
#define dump_mmp_msg(sb, mmp, msg)                                      \
        __dump_mmp_msg(sb, mmp, "", 0, "")
#define ext4_grp_locked_error(sb, grp, ino, block, fmt, ...)            \
do {                                                                    \
        no_printk(fmt, ##__VA_ARGS__);                          \
        __ext4_grp_locked_error("", 0, sb, grp, ino, block, " ");       \
} while (0)

#endif

extern void ext4_update_dynamic_rev(struct super_block *sb);
extern int ext4_update_compat_feature(handle_t *handle, struct super_block *sb,
                                        __u32 compat);
extern int ext4_update_rocompat_feature(handle_t *handle,
                                        struct super_block *sb, __u32 rocompat);
extern int ext4_update_incompat_feature(handle_t *handle,
                                        struct super_block *sb, __u32 incompat);
extern ext4_fsblk_t ext4_block_bitmap(struct super_block *sb,
                                      struct ext4_group_desc *bg);
extern ext4_fsblk_t ext4_inode_bitmap(struct super_block *sb,
                                      struct ext4_group_desc *bg);
extern ext4_fsblk_t ext4_inode_table(struct super_block *sb,
                                     struct ext4_group_desc *bg);
extern __u32 ext4_free_group_clusters(struct super_block *sb,
                                      struct ext4_group_desc *bg);
extern __u32 ext4_free_inodes_count(struct super_block *sb,
                                 struct ext4_group_desc *bg);
extern __u32 ext4_used_dirs_count(struct super_block *sb,
                                struct ext4_group_desc *bg);
extern __u32 ext4_itable_unused_count(struct super_block *sb,
                                   struct ext4_group_desc *bg);
extern void ext4_block_bitmap_set(struct super_block *sb,
                                  struct ext4_group_desc *bg, ext4_fsblk_t blk);
extern void ext4_inode_bitmap_set(struct super_block *sb,
                                  struct ext4_group_desc *bg, ext4_fsblk_t blk);
extern void ext4_inode_table_set(struct super_block *sb,
                                 struct ext4_group_desc *bg, ext4_fsblk_t blk);
extern void ext4_free_group_clusters_set(struct super_block *sb,
                                         struct ext4_group_desc *bg,
                                         __u32 count);
extern void ext4_free_inodes_set(struct super_block *sb,
                                struct ext4_group_desc *bg, __u32 count);
extern void ext4_used_dirs_set(struct super_block *sb,
                                struct ext4_group_desc *bg, __u32 count);
extern void ext4_itable_unused_set(struct super_block *sb,
                                   struct ext4_group_desc *bg, __u32 count);
extern int ext4_group_desc_csum_verify(struct super_block *sb, __u32 group,
                                       struct ext4_group_desc *gdp);
extern void ext4_group_desc_csum_set(struct super_block *sb, __u32 group,
                                     struct ext4_group_desc *gdp);
extern int ext4_register_li_request(struct super_block *sb,
                                    ext4_group_t first_not_zeroed);

static inline int ext4_has_group_desc_csum(struct super_block *sb)
{
        return ext4_has_feature_gdt_csum(sb) ||
               EXT4_SB(sb)->s_chksum_driver != NULL;
}

static inline int ext4_has_metadata_csum(struct super_block *sb)
{
        WARN_ON_ONCE(ext4_has_feature_metadata_csum(sb) &&
                     !EXT4_SB(sb)->s_chksum_driver);

        return (EXT4_SB(sb)->s_chksum_driver != NULL);
}
static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
{
        return ((ext4_fsblk_t)le32_to_cpu(es->s_blocks_count_hi) << 32) |
                le32_to_cpu(es->s_blocks_count_lo);
}

static inline ext4_fsblk_t ext4_r_blocks_count(struct ext4_super_block *es)
{
        return ((ext4_fsblk_t)le32_to_cpu(es->s_r_blocks_count_hi) << 32) |
                le32_to_cpu(es->s_r_blocks_count_lo);
}

static inline ext4_fsblk_t ext4_free_blocks_count(struct ext4_super_block *es)
{
        return ((ext4_fsblk_t)le32_to_cpu(es->s_free_blocks_count_hi) << 32) |
                le32_to_cpu(es->s_free_blocks_count_lo);
}

static inline void ext4_blocks_count_set(struct ext4_super_block *es,
                                         ext4_fsblk_t blk)
{
        es->s_blocks_count_lo = cpu_to_le32((u32)blk);
        es->s_blocks_count_hi = cpu_to_le32(blk >> 32);
}

static inline void ext4_free_blocks_count_set(struct ext4_super_block *es,
                                              ext4_fsblk_t blk)
{
        es->s_free_blocks_count_lo = cpu_to_le32((u32)blk);
        es->s_free_blocks_count_hi = cpu_to_le32(blk >> 32);
}

static inline void ext4_r_blocks_count_set(struct ext4_super_block *es,
                                           ext4_fsblk_t blk)
{
        es->s_r_blocks_count_lo = cpu_to_le32((u32)blk);
        es->s_r_blocks_count_hi = cpu_to_le32(blk >> 32);
}

static inline loff_t ext4_isize(struct ext4_inode *raw_inode)
{
        if (S_ISREG(le16_to_cpu(raw_inode->i_mode)))
                return ((loff_t)le32_to_cpu(raw_inode->i_size_high) << 32) |
                        le32_to_cpu(raw_inode->i_size_lo);
        else
                return (loff_t) le32_to_cpu(raw_inode->i_size_lo);
}

static inline void ext4_isize_set(struct ext4_inode *raw_inode, loff_t i_size)
{
        raw_inode->i_size_lo = cpu_to_le32(i_size);
        raw_inode->i_size_high = cpu_to_le32(i_size >> 32);
}

static inline
struct ext4_group_info *ext4_get_group_info(struct super_block *sb,
                                            ext4_group_t group)
{
         struct ext4_group_info ***grp_info;
         long indexv, indexh;
         BUG_ON(group >= EXT4_SB(sb)->s_groups_count);
         grp_info = EXT4_SB(sb)->s_group_info;
         indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb));
         indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1);
         return grp_info[indexv][indexh];
}

/*
 * Reading s_groups_count requires using smp_rmb() afterwards.  See
 * the locking protocol documented in the comments of ext4_group_add()
 * in resize.c
 */
static inline ext4_group_t ext4_get_groups_count(struct super_block *sb)
{
        ext4_group_t    ngroups = EXT4_SB(sb)->s_groups_count;

        smp_rmb();
        return ngroups;
}

static inline ext4_group_t ext4_flex_group(struct ext4_sb_info *sbi,
                                             ext4_group_t block_group)
{
        return block_group >> sbi->s_log_groups_per_flex;
}

static inline unsigned int ext4_flex_bg_size(struct ext4_sb_info *sbi)
{
        return 1 << sbi->s_log_groups_per_flex;
}

#define ext4_std_error(sb, errno)                               \
do {                                                            \
        if ((errno))                                            \
                __ext4_std_error((sb), __func__, __LINE__, (errno));    \
} while (0)

#ifdef CONFIG_SMP
/* Each CPU can accumulate percpu_counter_batch clusters in their local
 * counters. So we need to make sure we have free clusters more
 * than percpu_counter_batch  * nr_cpu_ids. Also add a window of 4 times.
 */
#define EXT4_FREECLUSTERS_WATERMARK (4 * (percpu_counter_batch * nr_cpu_ids))
#else
#define EXT4_FREECLUSTERS_WATERMARK 0
#endif

/* Update i_disksize. Requires i_mutex to avoid races with truncate */
static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
{
        WARN_ON_ONCE(S_ISREG(inode->i_mode) &&
                     !inode_is_locked(inode));
        down_write(&EXT4_I(inode)->i_data_sem);
        if (newsize > EXT4_I(inode)->i_disksize)
                EXT4_I(inode)->i_disksize = newsize;
        up_write(&EXT4_I(inode)->i_data_sem);
}

/* Update i_size, i_disksize. Requires i_mutex to avoid races with truncate */
static inline int ext4_update_inode_size(struct inode *inode, loff_t newsize)
{
        int changed = 0;

        if (newsize > inode->i_size) {
                i_size_write(inode, newsize);
                changed = 1;
        }
        if (newsize > EXT4_I(inode)->i_disksize) {
                ext4_update_i_disksize(inode, newsize);
                changed |= 2;
        }
        return changed;
}

int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
                                      loff_t len);

struct ext4_group_info {
        unsigned long   bb_state;
        struct rb_root  bb_free_root;
        ext4_grpblk_t   bb_first_free;  /* first free block */
        ext4_grpblk_t   bb_free;        /* total free blocks */
        ext4_grpblk_t   bb_fragments;   /* nr of freespace fragments */
        ext4_grpblk_t   bb_largest_free_order;/* order of largest frag in BG */
        struct          list_head bb_prealloc_list;
#ifdef DOUBLE_CHECK
        void            *bb_bitmap;
#endif
        struct rw_semaphore alloc_sem;
        ext4_grpblk_t   bb_counters[];  /* Nr of free power-of-two-block
                                         * regions, index is order.
                                         * bb_counters[3] = 5 means
                                         * 5 free 8-block regions. */
};

#define EXT4_GROUP_INFO_NEED_INIT_BIT           0
#define EXT4_GROUP_INFO_WAS_TRIMMED_BIT         1
#define EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT     2
#define EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT     3

#define EXT4_MB_GRP_NEED_INIT(grp)      \
        (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
#define EXT4_MB_GRP_BBITMAP_CORRUPT(grp)        \
        (test_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &((grp)->bb_state)))
#define EXT4_MB_GRP_IBITMAP_CORRUPT(grp)        \
        (test_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &((grp)->bb_state)))

#define EXT4_MB_GRP_WAS_TRIMMED(grp)    \
        (test_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
#define EXT4_MB_GRP_SET_TRIMMED(grp)    \
        (set_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))
#define EXT4_MB_GRP_CLEAR_TRIMMED(grp)  \
        (clear_bit(EXT4_GROUP_INFO_WAS_TRIMMED_BIT, &((grp)->bb_state)))

#define EXT4_MAX_CONTENTION             8
#define EXT4_CONTENTION_THRESHOLD       2

static inline spinlock_t *ext4_group_lock_ptr(struct super_block *sb,
                                              ext4_group_t group)
{
        return bgl_lock_ptr(EXT4_SB(sb)->s_blockgroup_lock, group);
}

/*
 * Returns true if the filesystem is busy enough that attempts to
 * access the block group locks has run into contention.
 */
static inline int ext4_fs_is_busy(struct ext4_sb_info *sbi)
{
        return (atomic_read(&sbi->s_lock_busy) > EXT4_CONTENTION_THRESHOLD);