i386/junos/ucla/src/lab5/inc/fs.h

   1 // See COPYRIGHT for copyright information.
   2
   3 #ifndef JOS_INC_FS_H
   4 #define JOS_INC_FS_H
   5
   6 #include <inc/types.h>
   7 #include <inc/mmu.h>
   8
   9 // Bytes per file system block - same as page size
  10 #define BLKSIZE         PGSIZE
  11
  12 // Maximum size of a filename (a single path component), including null
  13 #define MAXNAMELEN      120
  14
  15 // Maximum size of a complete pathname, including null
  16 #define MAXPATHLEN      1024
  17
  18 // Number of block pointers in an Inode
  19 #define NDIRECT         1018
  20
  21 // Maximum file size
  22 #define MAXFILESIZE     (NDIRECT * BLKSIZE)
  23
  24 // Typedefs for block numbers and inode numbers
  25 typedef int32_t blocknum_t;
  26 typedef int32_t inum_t;
  27
  28
  29 // File system directory entry (in memory and on disk)
  30 struct Direntry {
  31         inum_t de_inum;                 // inode number of entry
  32         int32_t de_namelen;             // length of filename
  33         char de_name[MAXNAMELEN];       // filename
  34 } __attribute__((packed));      // required on some 64-bit machines
  35
  36
  37 // File system super-block (in memory and on disk)
  38 #define FS_MAGIC        0x4A0530AE      // related vaguely to 'J\0S!'
  39
  40 struct Super {
  41         uint32_t s_magic;               // Magic number: FS_MAGIC
  42         blocknum_t s_nblocks;           // number of blocks in file system
  43         inum_t s_ninodes;               // number of inodes in file system
  44
  45         struct Direntry s_root;         // directory entry for root
  46                                         // (convenient to have around)
  47 } __attribute__((packed));      // required on some 64-bit machines
  48
  49
  50 // File system inode (in memory and on disk; sizeof(struct Inode) == BLKSIZE)
  51 struct Inode {
  52         uint32_t i_ftype;               // file type
  53         uint32_t i_refcount;            // number of hard links
  54         off_t i_size;                   // file size in bytes
  55
  56         blocknum_t i_direct[NDIRECT];   // block pointers
  57
  58         // These fields only have meaning in memory:
  59         inum_t i_inum;                  // inode number
  60         uint32_t i_opencount;           // number of memory references
  61         uint32_t i_fsck_refcount : 31;  // used during fsck
  62         unsigned i_fsck_checked : 1;
  63 } __attribute__((packed));      // required on some 64-bit machines
  64
  65 // File types (Inode::i_type)
  66 #define FTYPE_REG       1       // Regular file
  67 #define FTYPE_DIR       2       // Directory
  68
  69
  70 // Buffer cache requests
  71
  72 #define BCREQ_MAP               0       // Map this block without locking
  73 #define BCREQ_MAP_RLOCK         1       // Map this block + shared lock
  74 #define BCREQ_MAP_WLOCK         2       // Map this block + exclusive lock
  75 #define BCREQ_UNLOCK            3       // Unlock previous RLOCK or WLOCK
  76 #define BCREQ_FLUSH             4       // Flush this block's contents to disk
  77 #define BCREQ_UNLOCK_FLUSH      5       // == UNLOCK + FLUSH
  78 #define BCREQ_INITIALIZE        6       // Mark block as initialized
  79
  80 #define MAKE_BCREQ(blockno, reqtype)    ((blockno << 4) | (reqtype))
  81 #define BCREQ_BLOCKNUM(bcreq)           (((bcreq) >> 4) & 0xFFFFFFF)
  82 #define BCREQ_TYPE(bcreq)               ((bcreq) & 0xF)
  83
  84 #endif /* !JOS_INC_FS_H */