fs_bfs(4)

fs (bfs) -- format of the bfs file system volume

Synopsis

   #include <sys/types.h>
   #include <sys/fs/bfs.h>

Description

The bfs superblock is stored on sector 0. Its format is:

   struct bfs_bdsuphead
   {
   	long   bh_bfsmagic;   /* Magic number */
   	off_t  bh_start;      /* Filesystem data start offset */
   	off_t  bh_end;        /* Filesystem data end offset */
   };
   
   /*
    * The sanity structure is used to promote sanity in compaction.  Used
    * correctly, a crash at any point during compaction is recoverable.
    */
   struct bfs_sanity
   {
   	daddr_t fromblock;    /* "From" block of current transfer */
   	daddr_t toblock;      /* "To" block of current transfer */
   	daddr_t bfromblock;   /* Backup of "from" block */
   	daddr_t btoblock;     /* Backup of "to" block */
   };
   

   struct bdsuper
   {
   	struct bfs_bdsuphead bdsup_head;  /* Header info */
   	struct bfs_sanity bdsup_sane;     /* Crash recovery info whilst
                                                compacting */
   	char    bdsup_fsname[6];          /* file system name */
   	char    bdsup_volume[6];          /* file system volume name */
   	long    bdsup_filler[118];        /* Padding */
   

   };
   #define BFS_MAGIC   0x1BADFACE         /* bfs magic number */

The sanity structure is used to promote sanity during compaction. It is used by fsck(1M) to recover from a system crash at any point during compaction.

References

inode_bfs(4)