o2fs.h

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#ifndef __FS_O2FS_H__
#define __FS_O2FS_H__
 
/*
 * *** Disk Layout ***
 *
 * +---------------------+
 * | Super Blocks (4MBs) |
 * +---------------------+
 * |                     |
 *           .
 *           .
 *           .
 * |                     |
 * +---------------------+
 * | Super Blocks (4MBs) |
 * +---------------------+
 *
 */
 
#define MAXUSERNAMELEN  32
#define MAXNAMELEN      255
 
/*
 * *** Version History ***
 * 1.0          Initial release
 */
 
#define O2FS_VERSION_MAJOR      1
#define O2FS_VERSION_MINOR      0
 
/*
 * Object ID: Pointer to a block node
 */
typedef struct ObjID {
    uint8_t             hash[32];
    uint64_t            device;
    uint64_t            offset;
} ObjID;
 
/*
 * Super block
 */
typedef struct SuperBlock
{
    uint8_t             magic[8];       /* Superblock Magic */
    uint16_t            versionMajor;   /* Major Version Number */
    uint16_t            versionMinor;   /* Minor Version Number */
    uint32_t            _rsvd0;
    uint64_t            features;       /* Feature Flags */
    uint64_t            blockCount;     /* Total Blocks */
    uint64_t            blockSize;      /* Block Size in Bytes */
    uint64_t            bitmapSize;     /* Free Bitmap Size in Bytes */
    uint64_t            bitmapOffset;   /* Free Bitmap Offset */
 
    uint64_t            version;        /* Snapshot version */
    ObjID               root;           /* Root Tree */
 
    uint8_t             hash[32];
} SuperBlock;
 
#define SUPERBLOCK_MAGIC        "SUPRBLOK"
 
/*
 * Block Pointer: Address raw blocks on the disk
 */
typedef struct BPtr {
    uint8_t             hash[32];
    uint64_t            device;
    uint64_t            offset;
    uint64_t            _rsvd0;
    uint64_t            _rsvd1;
} BPtr;
 
 
#define O2FS_DIRECT_PTR         (64)
 
/*
 * Block Nodes: Contain indirect pointers to pieces of a file
 */
typedef struct BNode
{
    uint8_t             magic[8];
    uint16_t            versionMajor;
    uint16_t            versionMinor;
    uint32_t            flags;
    uint64_t            size;
 
    BPtr                direct[O2FS_DIRECT_PTR];
} BNode;
 
#define BNODE_MAGIC     "BLOKNODE"
 
/*
 * Directory entries are exactly 512 bytes
 */
typedef struct BDirEntry
{
    uint8_t             magic[8];
    ObjID               objId;
    uint64_t            size;
    uint64_t            flags;
    uint64_t            ctime;
    uint64_t            mtime;
    uint8_t             user[MAXUSERNAMELEN]; // Not null terminated
    uint8_t             group[MAXUSERNAMELEN];
    uint8_t             padding[104];
    uint8_t             name[MAXNAMELEN+1]; // Null terminated
} BDirEntry;
 
#define BDIR_MAGIC      "DIRENTRY"
 
#endif /* __FS_O2FS_H__ */