NT4/private/ntos/boot/bootcode/hpfs/i386/fnode.inc

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2001-01-01 00:00:00 +01:00
;** FNODE.H - Fnode definitions
;
; FILESYS
; Gregory A. Jones
; Copyright 1988 Microsoft Corporation
;
; Modification history:
; P.A. Williams 06/01/89 Added fields FN_ACLBASE and FN_NEACNT
; to fnode.
; P.A. Williams 08/01/89 Added typedef FNODE and PFNODE, ALBLK, PALBLK,
; ALLEAF, PALLEAF, ALSEC, and PALSEC.
;
;* File Allocation Tracking
;
; File space is allocated as a list of extents, each extent as
; large as we can make it. This list is kept in a B+TREE format.
; Each B+TREE block consists of a single sector containing an
; ALSEC record, except for the top most block. The topmost block
; consists of just an ALBLK structure, is usually much smaller than
; 512 bytes, and is typically included in another structure.
;
; The leaf block(s) in the tree contain triples which indicate
; the logical to physical mapping for this file. Typically this
; extent list is small enough that it is wholy contained in the
; fnode ALBLK stucture. If more than ALCNT extents are required
; then the tree is split into two levels. Note that when the
; topmost B+TREE block is 'split' no actual split is necessary,
; since the new child block is much bigger than the parent block
; and can contain all of the old records plus the new one. Thus,
; we can have B+TREEs where the root block contains only one
; downpointer.
;
; The following rules apply:
;
; 1) if the file is not empty, there is at least one sector allocated
; to logical offset 0. This simplifys some critical loops.
;
; 2) The last entry in the last node block contains a AN_LOF value of
; FFFFFFFF. This allows us to extend that last leaf block
; without having to update the node block.
;
; 3) For the node records, the AN_SEC points to a node or leaf
; sector which describes extents which occur before that
; record's AN_LOF value.
;
;* Allocation block structure
;
; Each allocation block consists of one of these. This may be
; a small block imbedded in an FNODE or OFT structure, or it
; may occupy a whole sector and be embedded in an ALSEC structure.
;
ALBLK struc
AB_FLAG db ? ; flags
AB_FLAG2 db 3 dup (?) ; unused - sometimes copied with AB_FLAG
AB_FCNT db ? ; free count - slots for ALLEAF or ALNODE
AB_OCNT db ? ; occupied count - # of ALLEAF or ALNODEs
AB_FREP dw ? ; offset to last item+1
; ALLEAF or ALNODE records go here
ALBLK ends
ABF_NODE equ 80h ; if not a leaf node
ABF_BIN equ 40h ; suggest using binary search to find
ABF_FNP equ 20h ; parent is an FNODE
ABF_NFG equ 01h ; not a flag, high order bit of AB_FREP
; Allocation Node Structure
;
; These follow an ALBLK header for a node block
ALNODE struc
AN_LOF dd ? ; logical offset (sectors
AN_SEC dd ? ; sector for guys < this
ALNODE ends
; Allocation Leaf Structure
;
; These follow an ALBLK header in a leaf block
ALLEAF struc
AL_LOF dd ? ; logical sector offset (sectors)
AL_LEN dd ? ; length of extent (sectors)
AL_POF dd ? ; physical sector offset (sectors)
ALLEAF ends
;* Allocation Sector Structure
;
; Root ALBLK structures are contained within other structures,
; such as the FNODE. When the B+TREE is more than one level,
; though, the non-root nodes are each held in a sector.
;
; This structure defines that format
;
ALSEC struc
AS_SIG dd ? ; signature
AS_SEC dd ? ; sector # of this sector
AS_RENT dd ? ; parent sector # or FNODE #
AS_ALBLK db (size ALBLK) dup (?) ; ALBLK goes here
; ALNODE or ALLEAF records start here
ALSEC ends
; # of bytes available for ALLEAF or ALNODE values. Size chosen
; so an integral # of either structure fits
ifdef MASM
ASSIZ equ ((SECSIZE - size ALSEC)/24*24)
.errnz size ALLEAF-12
.errnz size ALNODE-8
.errnz (ASSIZ + AL_LOF + size AL_LOF + size ALBLK) GT 512 ; extra room for an AL_LOF value
else
ASSIZ equ ((SECSIZE - size ALSEC)/24*24)
endif
; AuxInfo Structure
;
; The FNODE contains two AuxInfo structures, one for ACLs and
; one for EAs.
;
; These structures point to within FNODE storage and also
; potentially point to an overflow area which is an ALBLK structure.
; The AI_FNL stuff is stored in the FN_FREE area, the ACLs first
; and the EAs second, any free space following. The start of the
; EAs can be found by offseting FN_FREE with FN_ACL.AI_FNL
;
AUXINFO struc
AI_DAL dd ? ; non-fnode Disk Allocation length
AI_SEC dd ? ; sec # of first sec in extent or of ALSEC
AI_FNL dw ? ; length of fnode info
AI_DAT db ? ; non-zero if AI_SEC points to ALSEC
AUXINFO ends
;* Fnode block definition
;
; Every file and directory has an FNODE. The file location
; stuff is only used for files; directories are kept in
; a BTREE of DIRBLK records pointed to by FN_SEC[0].RSEC
;
ALCNT equ 8 ; 8 ALLEAF records in an FN_AT entry
LEAFPERFNODE equ 8 ; 8 ALLEAF records in an FN_AT entry
NODEPERFNODE equ 12 ; 12 ALNODE records in an FNODE.
LEAFPERSEC equ 40 ; ALLEAF records in an allocation sector
NODEPERSEC equ 60 ; ALNODE records in an allocation sector
FNODE struc
; The following file location information is copied into the OFT
; and is used there during normal file access. The stuff in the
; fnode record here may in fact be out of date for open files.
; See the OFN_ in the OFT structure THESE TWO AREAS IN THE
; RESPECTIVE RECORDS MUST HAVE IDENTICAL FORMATS.
;
; There are two kinds of location info: FNSCNT SPTR records
; and then a single, double, triple, and quad indirect block pointer.
; The "block threshold" means the first sector number which is
; contained in that indirect block heirarchy. You use this
; to quickly find out where to start looking.
;
FN_SIG dd ? ; signature value
; History tracking info for softer software
FN_SRH dd ? ; sequential read history
FN_FRH dd ? ; fast read history
FN_NAME db 16 dup (?) ; 1st 18 bytes of file name
FN_CONTFN dd ? ; fnode of directory cont. this file/dir
; stuff not interesting once opened
FN_ACL db (size AUXINFO) dup (?) ; access ctl list aux info structure
FN_HCNT db ? ; count of valid history bits
FN_EA db (size AUXINFO) dup (?) ; ea aux info structure
FN_FLAG db ? ; FNODE flag byte
FN_AB db (size ALBLK) dup (?) ; allocation block structure
FN_ALREC db (ALCNT*size ALLEAF) dup (?) ; referenced from FN_AB
FN_VLEN dd ? ; length of valid data in file. if DIR_SIZE
; is > FN_VLEN then the space inbetween
; must be zapped before being shown to user
FN_NEACNT dd ? ; # of "need eas" in file
; The following fields are unused in this release, they're for
; future compatibility. When deleting files, if FN_EEL is non-zero
; then FN_EEL sectors starting at FN_EEP must be released too.
;
FN_UID db 16 dup (?) ; reserved for UID value
FN_ACLBASE dw ? ; FN_ACLBASE offset of 1st ACE in fnode
FN_SPARE db 10 dup (?); 10 more bytes emergency spares
; Free pool. ACLs and EAs are stored here via the AUXINFO structure
FN_FREE db 316 dup (?) ; free space for perm and env list; perm list
; comes first.
FNODE ends
ifdef MASM
.errnz AL_LOF ; verify validity of FN_DMY1 hack above
.errnz size AL_LOF-4
endif
; Fnode FN_FLAG bits
FNF_DIR equ 01h ; is a directory fnode