ext4: Convert ext4_lock_group to use sb_bgl_lock

[mirror_ubuntu-bionic-kernel.git] / fs / ext4 / ext4.h

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

/*
 * The fourth extended filesystem constants/structures
 */

/*
 * 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(f, a...)     do {} while (0)
#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;


/* prefer goal again. length */
#define EXT4_MB_HINT_MERGE              1
/* blocks already reserved */
#define EXT4_MB_HINT_RESERVED           2
/* metadata is being allocated */
#define EXT4_MB_HINT_METADATA           4
/* first blocks in the file */
#define EXT4_MB_HINT_FIRST              8
/* search for the best chunk */
#define EXT4_MB_HINT_BEST               16
/* data is being allocated */
#define EXT4_MB_HINT_DATA               32
/* don't preallocate (for tails) */
#define EXT4_MB_HINT_NOPREALLOC         64
/* allocate for locality group */
#define EXT4_MB_HINT_GROUP_ALLOC        128
/* allocate goal blocks or none */
#define EXT4_MB_HINT_GOAL_ONLY          256
/* goal is meaningful */
#define EXT4_MB_HINT_TRY_GOAL           512
/* blocks already pre-reserved by delayed allocation */
#define EXT4_MB_DELALLOC_RESERVED      1024


struct ext4_allocation_request {
        /* target inode for block we're allocating */
        struct inode *inode;
        /* logical block in target inode */
        ext4_lblk_t logical;
        /* phys. target (a hint) */
        ext4_fsblk_t goal;
        /* the closest logical allocated block to the left */
        ext4_lblk_t lleft;
        /* phys. block for ^^^ */
        ext4_fsblk_t pleft;
        /* the closest logical allocated block to the right */
        ext4_lblk_t lright;
        /* phys. block for ^^^ */
        ext4_fsblk_t pright;
        /* how many blocks we want to allocate */
        unsigned int len;
        /* flags. see above EXT4_MB_HINT_* */
        unsigned int flags;
};

/*
 * Special inodes numbers
 */
#define EXT4_BAD_INO             1      /* Bad blocks inode */
#define EXT4_ROOT_INO            2      /* Root 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
#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))
#ifdef __KERNEL__
# define EXT4_BLOCK_SIZE_BITS(s)        ((s)->s_blocksize_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)))

/*
 * 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) */
        __u32   bg_reserved[2];         /* Likely block/inode bitmap checksum */
        __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 */
        __u32   bg_reserved2[3];
};

/*
 * Structure of a flex block group info
 */

struct flex_groups {
        atomic_t free_inodes;
        atomic_t free_blocks;
        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_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 */
#define EXT4_ECOMPR_FL                  0x00000800 /* Compression error */
/* 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_EXT_MIGRATE                0x00100000 /* Inode is migrating */
#define EXT4_RESERVED_FL                0x80000000 /* reserved for ext4 lib */

#define EXT4_FL_USER_VISIBLE            0x000BDFFF /* User visible flags */
#define EXT4_FL_USER_MODIFIABLE         0x000B80FF /* User modifiable flags */

/* 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_IMMUTABLE_FL | EXT4_APPEND_FL |\
                           EXT4_NODUMP_FL | EXT4_NOATIME_FL |\
                           EXT4_NOCOMPR_FL | EXT4_JOURNAL_DATA_FL |\
                           EXT4_NOTAIL_FL | EXT4_DIRSYNC_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 dynamic state flags
 */
#define EXT4_STATE_JDATA                0x00000001 /* journaled data exists */
#define EXT4_STATE_NEW                  0x00000002 /* inode is newly created */
#define EXT4_STATE_XATTR                0x00000004 /* has in-inode xattrs */
#define EXT4_STATE_NO_EXPAND            0x00000008 /* No space for expansion */
#define EXT4_STATE_DA_ALLOC_CLOSE       0x00000010 /* Alloc DA blks on close */

/* 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;
};

/* 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;
};

/*
 * Following is used by preallocation code to tell get_blocks() that we
 * want uninitialzed extents.
 */
#define EXT4_CREATE_UNINITIALIZED_EXT           2

/*
 * 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
#ifdef CONFIG_JBD2_DEBUG
#define EXT4_IOC_WAIT_FOR_READONLY      _IOR('f', 99, long)
#endif
#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)

/*
 * 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)
#ifdef CONFIG_JBD2_DEBUG
#define EXT4_IOC32_WAIT_FOR_READONLY    _IOR('f', 99, int)
#endif
#define EXT4_IOC32_GETVERSION_OLD       FS_IOC32_GETVERSION
#define EXT4_IOC32_SETVERSION_OLD       FS_IOC32_SETVERSION


/*
 *  Mount options
 */
struct ext4_mount_options {
        unsigned long s_mount_opt;
        uid_t s_resuid;
        gid_t s_resgid;
        unsigned long s_commit_interval;
        u32 s_min_batch_time, s_max_batch_time;
#ifdef CONFIG_QUOTA
        int s_jquota_fmt;
        char *s_qf_names[MAXQUOTAS];
#endif
};

/*
 * 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] */
                        __u32   l_i_reserved2;
                } 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_pad1;
        __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 */
};


#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))                   \

static inline __le32 ext4_encode_extra_time(struct timespec *time)
{
       return cpu_to_le32((sizeof(time->tv_sec) > 4 ?
                           time->tv_sec >> 32 : 0) |
                           ((time->tv_nsec << 2) & EXT4_NSEC_MASK));
}

static inline void ext4_decode_extra_time(struct timespec *time, __le32 extra)
{
       if (sizeof(time->tv_sec) > 4)
               time->tv_sec |= (__u64)(le32_to_cpu(extra) & EXT4_EPOCH_MASK)
                               << 32;
       time->tv_nsec = (le32_to_cpu(extra) & EXT4_NSEC_MASK) >> 2;
}

#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);            \
} 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);               \
        if (EXT4_FITS_IN_INODE(raw_inode, einode, xtime ## _extra))            \
                ext4_decode_extra_time(&(einode)->xtime,                       \
                                       raw_inode->xtime ## _extra);            \
} 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_reserved2     osd2.linux2.l_i_reserved2

#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__) */

/*
 * storage for cached extent
 */
struct ext4_ext_cache {
        ext4_fsblk_t    ec_start;
        ext4_lblk_t     ec_block;
        __u32           ec_len; /* must be 32bit to return holes */
        __u32           ec_type;
};

/*
 * fourth extended file system inode data in memory
 */
struct ext4_inode_info {
        __le32  i_data[15];     /* unconverted */
        __u32   i_flags;
        ext4_fsblk_t    i_file_acl;
        __u32   i_dtime;

        /*
         * 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;
        __u32   i_state;                /* Dynamic state flags for ext4 */

        ext4_lblk_t             i_dir_start_lookup;
#ifdef CONFIG_EXT4_FS_XATTR
        /*
         * 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;
#endif
#ifdef CONFIG_EXT4_FS_POSIX_ACL
        struct posix_acl        *i_acl;
        struct posix_acl        *i_default_acl;
#endif

        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;
        struct inode vfs_inode;
        struct jbd2_inode jinode;

        struct ext4_ext_cache i_cached_extent;
        /*
         * 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;

        /* ialloc */
        ext4_group_t    i_last_alloc_group;

        /* allocation reservation info for delalloc */
        unsigned int i_reserved_data_blocks;
        unsigned int i_reserved_meta_blocks;
        unsigned int i_allocated_meta_blocks;
        unsigned short i_delalloc_reserved_flag;

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

        spinlock_t i_block_reservation_lock;
};

/*
 * 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
 */
#define EXT4_MOUNT_OLDALLOC             0x00002  /* Don't use the new Orlov allocator */
#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_MINIX_DF             0x00080 /* Mimics the Minix statfs */
#define EXT4_MOUNT_NOLOAD               0x00100 /* Don't use existing journal*/
#define EXT4_MOUNT_ABORT                0x00200 /* Fatal error detected */
#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_NOBH                 0x40000 /* No bufferheads */
#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_JOURNAL_CHECKSUM     0x800000 /* Journal checksums */
#define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT 0x1000000 /* Journal Async Commit */
#define EXT4_MOUNT_I_VERSION            0x2000000 /* i_version support */
#define EXT4_MOUNT_DELALLOC             0x8000000 /* Delalloc support */
#define EXT4_MOUNT_DATA_ERR_ABORT       0x10000000 /* Abort on file data write */

/* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
#ifndef _LINUX_EXT2_FS_H
#define clear_opt(o, opt)               o &= ~EXT4_MOUNT_##opt
#define set_opt(o, opt)                 o |= EXT4_MOUNT_##opt
#define test_opt(sb, opt)               (EXT4_SB(sb)->s_mount_opt & \
                                         EXT4_MOUNT_##opt)
#else
#define EXT2_MOUNT_NOLOAD               EXT4_MOUNT_NOLOAD
#define EXT2_MOUNT_ABORT                EXT4_MOUNT_ABORT
#define EXT2_MOUNT_DATA_FLAGS           EXT4_MOUNT_DATA_FLAGS
#endif

#define ext4_set_bit                    ext2_set_bit
#define ext4_set_bit_atomic             ext2_set_bit_atomic
#define ext4_clear_bit                  ext2_clear_bit
#define ext4_clear_bit_atomic           ext2_clear_bit_atomic
#define ext4_test_bit                   ext2_test_bit
#define ext4_find_first_zero_bit        ext2_find_first_zero_bit
#define ext4_find_next_zero_bit         ext2_find_next_zero_bit
#define ext4_find_next_bit              ext2_find_next_bit

/*
 * 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

/*
 * 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_obso_log_frag_size;   /* Obsoleted fragment size */
/*20*/  __le32  s_blocks_per_group;     /* # Blocks per group */
        __le32  s_obso_frags_per_group; /* Obsoleted fragments 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_reserved_char_pad;
        __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_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_reserved_char_pad2;
        __le16  s_reserved_pad;
        __le64  s_kbytes_written;       /* nr of lifetime kilobytes written */
        __u32   s_reserved[160];        /* Padding to the end of the block */
};

#ifdef __KERNEL__
/*
 * 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_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 */
        unsigned long s_overhead_last;  /* Last calculated overhead */
        unsigned long s_blocks_last;    /* Last seen block count */
        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 long  s_mount_opt;
        ext4_fsblk_t s_sb_block;
        uid_t s_resuid;
        gid_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;
        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_freeblocks_counter;
        struct percpu_counter s_freeinodes_counter;
        struct percpu_counter s_dirs_counter;
        struct percpu_counter s_dirtyblocks_counter;
        struct blockgroup_lock *s_blockgroup_lock;
        struct proc_dir_entry *s_proc;
        struct kobject s_kobj;
        struct completion s_kobj_unregister;

        /* Journaling */
        struct inode *s_journal_inode;
        struct journal_s *s_journal;
        struct list_head s_orphan;
        struct mutex s_orphan_lock;
        struct mutex s_resize_lock;
        unsigned long s_commit_interval;
        u32 s_max_batch_time;
        u32 s_min_batch_time;
        struct block_device *journal_bdev;
#ifdef CONFIG_JBD2_DEBUG
        struct timer_list turn_ro_timer;        /* For turning read-only (crash simulation) */
        wait_queue_head_t ro_wait_queue;        /* For people waiting for the fs to go read-only */
#endif
#ifdef CONFIG_QUOTA
        char *s_qf_names[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 */

#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;
        long s_blocks_reserved;
        spinlock_t s_reserve_lock;
        spinlock_t s_md_lock;
        tid_t s_last_transaction;
        unsigned short *s_mb_offsets;
        unsigned int *s_mb_maxs;

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

        /* history to debug policy */
        struct ext4_mb_history *s_mb_history;
        int s_mb_history_cur;
        int s_mb_history_max;
        int s_mb_history_num;
        spinlock_t s_mb_history_lock;
        int s_mb_history_filter;

        /* stats for buddy allocator */
        spinlock_t s_mb_pa_lock;
        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;

        /* locality groups */
        struct ext4_locality_group *s_locality_groups;

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

        unsigned int s_log_groups_per_flex;
        struct flex_groups *s_flex_groups;
};

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_JOURNAL_INO ||
                ino == EXT4_RESIZE_INO ||
                (ino >= EXT4_FIRST_INO(sb) &&
                 ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
}
#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

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

/*
 * Codes for operating systems
 */
#define EXT4_OS_LINUX           0
#define EXT4_OS_HURD            1
#define EXT4_OS_MASIX           2
#define EXT4_OS_FREEBSD         3
#define EXT4_OS_LITES           4

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

#define EXT4_CURRENT_REV        EXT4_GOOD_OLD_REV
#define EXT4_MAX_SUPP_REV       EXT4_DYNAMIC_REV

#define EXT4_GOOD_OLD_INODE_SIZE 128

/*
 * Feature set definitions
 */

#define EXT4_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_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_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_COMPAT_SUPP        EXT2_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)
#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)

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

/*
 * 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 */
};

/*
 * 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

/*
 * 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)

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

#define is_dx(dir) (EXT4_HAS_COMPAT_FEATURE(dir->i_sb, \
                                      EXT4_FEATURE_COMPAT_DIR_INDEX) && \
                      (EXT4_I(dir)->i_flags & EXT4_INDEX_FL))
#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

#ifdef __KERNEL__

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

#define EXT4_HTREE_EOF  0x7fffffff

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


/*
 * 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  -75000

void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
                        ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp);

extern struct proc_dir_entry *ext4_proc_root;

/*
 * 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(struct buffer_head *, unsigned);

/* balloc.c */
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 long *count, int *errp);
extern int ext4_claim_free_blocks(struct ext4_sb_info *sbi, s64 nblocks);
extern int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks);
extern void ext4_free_blocks(handle_t *handle, struct inode *inode,
                        ext4_fsblk_t block, unsigned long count, int metadata);
extern void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
                                ext4_fsblk_t block, unsigned long count);
extern ext4_fsblk_t ext4_count_free_blocks(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);
struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
                                      ext4_group_t block_group);
extern unsigned ext4_init_block_bitmap(struct super_block *sb,
                                       struct buffer_head *bh,
                                       ext4_group_t group,
                                       struct ext4_group_desc *desc);
#define ext4_free_blocks_after_init(sb, group, desc)                    \
                ext4_init_block_bitmap(sb, NULL, group, desc)

/* dir.c */
extern int ext4_check_dir_entry(const char *, struct inode *,
                                struct ext4_dir_entry_2 *,
                                struct buffer_head *, unsigned int);
extern int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
                                    __u32 minor_hash,
                                    struct ext4_dir_entry_2 *dirent);
extern void ext4_htree_free_dir_info(struct dir_private_info *p);

/* fsync.c */
extern int ext4_sync_file(struct file *, struct dentry *, 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 *, int);
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 unsigned ext4_init_inode_bitmap(struct super_block *sb,
                                       struct buffer_head *bh,
                                       ext4_group_t group,
                                       struct ext4_group_desc *desc);
extern void mark_bitmap_end(int start_bit, int end_bit, char *bitmap);

/* mballoc.c */
extern long ext4_mb_stats;
extern long ext4_mb_max_to_scan;
extern int ext4_mb_init(struct super_block *, int);
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 init_ext4_mballoc(void);
extern void exit_ext4_mballoc(void);
extern void ext4_mb_free_blocks(handle_t *, struct inode *,
                unsigned long, unsigned long, int, unsigned long *);
extern int ext4_mb_add_groupinfo(struct super_block *sb,
                ext4_group_t i, struct ext4_group_desc *desc);
extern void ext4_mb_update_group_info(struct ext4_group_info *grp,
                ext4_grpblk_t add);
extern int ext4_mb_get_buddy_cache_lock(struct super_block *, ext4_group_t);
extern void ext4_mb_put_buddy_cache_lock(struct super_block *,
                                                ext4_group_t, int);
/* inode.c */
int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
                struct buffer_head *bh, ext4_fsblk_t blocknr);
struct buffer_head *ext4_getblk(handle_t *, struct inode *,
                                                ext4_lblk_t, int, int *);
struct buffer_head *ext4_bread(handle_t *, struct inode *,
                                                ext4_lblk_t, int, int *);
int ext4_get_block(struct inode *inode, sector_t iblock,
                                struct buffer_head *bh_result, int create);

extern struct inode *ext4_iget(struct super_block *, unsigned long);
extern int  ext4_write_inode(struct inode *, int);
extern int  ext4_setattr(struct dentry *, struct iattr *);
extern int  ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
                                struct kstat *stat);
extern void ext4_delete_inode(struct inode *);
extern int  ext4_sync_inode(handle_t *, struct inode *);
extern void ext4_dirty_inode(struct inode *);
extern int ext4_change_inode_journal_flag(struct inode *, int);
extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
extern int ext4_can_truncate(struct inode *inode);
extern void ext4_truncate(struct inode *);
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_meta_trans_blocks(struct inode *, int nrblocks, int idxblocks);
extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
extern int ext4_block_truncate_page(handle_t *handle,
                struct address_space *mapping, loff_t from);
extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
extern qsize_t ext4_get_reserved_space(struct inode *inode);

/* 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 *);

/* namei.c */
extern unsigned int ext4_rec_len_from_disk(__le16 dlen, unsigned blocksize);
extern __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize);
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);

/* 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);

/* super.c */
extern void ext4_error(struct super_block *, const char *, const char *, ...)
        __attribute__ ((format (printf, 3, 4)));
extern void __ext4_std_error(struct super_block *, const char *, int);
extern void ext4_abort(struct super_block *, const char *, const char *, ...)
        __attribute__ ((format (printf, 3, 4)));
extern void ext4_warning(struct super_block *, const char *, const char *, ...)
        __attribute__ ((format (printf, 3, 4)));
extern void ext4_grp_locked_error(struct super_block *, ext4_group_t,
                                const char *, const char *, ...)
        __attribute__ ((format (printf, 4, 5)));
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_blks_count(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_blks_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 __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
                                   struct ext4_group_desc *gdp);
extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
                                       struct ext4_group_desc *gdp);

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;
         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__, (errno));      \
} while (0)

#ifdef CONFIG_SMP
/* Each CPU can accumulate percpu_counter_batch blocks in their local
 * counters. So we need to make sure we have free blocks more
 * than percpu_counter_batch  * nr_cpu_ids. Also add a window of 4 times.
 */
#define EXT4_FREEBLOCKS_WATERMARK (4 * (percpu_counter_batch * nr_cpu_ids))
#else
#define EXT4_FREEBLOCKS_WATERMARK 0
#endif

static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
{
        /*
         * XXX: replace with spinlock if seen contended -bzzz
         */
        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);
        return ;
}

struct ext4_group_info {
        unsigned long   bb_state;
        struct rb_root  bb_free_root;
        unsigned short  bb_first_free;
        unsigned short  bb_free;
        unsigned short  bb_fragments;
        struct          list_head bb_prealloc_list;
#ifdef DOUBLE_CHECK
        void            *bb_bitmap;
#endif
        struct rw_semaphore alloc_sem;
        unsigned short  bb_counters[];
};

#define EXT4_GROUP_INFO_NEED_INIT_BIT   0

#define EXT4_MB_GRP_NEED_INIT(grp)      \
        (test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))

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);
}

static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
{
        spin_lock(ext4_group_lock_ptr(sb, group));
}

static inline void ext4_unlock_group(struct super_block *sb,
                                        ext4_group_t group)
{
        spin_unlock(ext4_group_lock_ptr(sb, group));
}

static inline int ext4_is_group_locked(struct super_block *sb,
                                        ext4_group_t group)
{
        return spin_is_locked(ext4_group_lock_ptr(sb, group));
}

/*
 * Inodes and files operations
 */

/* dir.c */
extern const struct file_operations ext4_dir_operations;

/* file.c */
extern const struct inode_operations ext4_file_inode_operations;
extern const struct file_operations ext4_file_operations;

/* namei.c */
extern const struct inode_operations ext4_dir_inode_operations;
extern const struct inode_operations ext4_special_inode_operations;
extern struct dentry *ext4_get_parent(struct dentry *child);

/* symlink.c */
extern const struct inode_operations ext4_symlink_inode_operations;
extern const struct inode_operations ext4_fast_symlink_inode_operations;

/* extents.c */
extern int ext4_ext_tree_init(handle_t *handle, struct inode *);
extern int ext4_ext_writepage_trans_blocks(struct inode *, int);
extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
                                       int chunk);
extern int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
                               ext4_lblk_t iblock, unsigned int max_blocks,
                               struct buffer_head *bh_result,
                               int create, int extend_disksize);
extern void ext4_ext_truncate(struct inode *);
extern void ext4_ext_init(struct super_block *);
extern void ext4_ext_release(struct super_block *);
extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
                          loff_t len);
extern int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode,
                        sector_t block, unsigned int max_blocks,
                        struct buffer_head *bh, int create,
                        int extend_disksize, int flag);
extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                        __u64 start, __u64 len);

/*
 * Add new method to test wether block and inode bitmaps are properly
 * initialized. With uninit_bg reading the block from disk is not enough
 * to mark the bitmap uptodate. We need to also zero-out the bitmap
 */
#define BH_BITMAP_UPTODATE BH_JBDPrivateStart

static inline int bitmap_uptodate(struct buffer_head *bh)
{
        return (buffer_uptodate(bh) &&
                        test_bit(BH_BITMAP_UPTODATE, &(bh)->b_state));
}
static inline void set_bitmap_uptodate(struct buffer_head *bh)
{
        set_bit(BH_BITMAP_UPTODATE, &(bh)->b_state);
}

#endif  /* __KERNEL__ */

#endif  /* _EXT4_H */