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linux/fs/hpfs/hpfs.h
Mikulas Patocka d0969d1949 HPFS: Fix some unaligned accesses 
Fix some unaligned accesses

Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-09 09:04:24 -07:00

569 lines
18 KiB
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/*
* linux/fs/hpfs/hpfs.h
*
* HPFS structures by Chris Smith, 1993
*
* a little bit modified by Mikulas Patocka, 1998-1999
*/
/* The paper
Duncan, Roy
Design goals and implementation of the new High Performance File System
Microsoft Systems Journal Sept 1989 v4 n5 p1(13)
describes what HPFS looked like when it was new, and it is the source
of most of the information given here. The rest is conjecture.
For definitive information on the Duncan paper, see it, not this file.
For definitive information on HPFS, ask somebody else -- this is guesswork.
There are certain to be many mistakes. */
#if !defined(__LITTLE_ENDIAN) && !defined(__BIG_ENDIAN)
#error unknown endian
#endif
/* Notation */
typedef u32 secno; /* sector number, partition relative */
typedef secno dnode_secno; /* sector number of a dnode */
typedef secno fnode_secno; /* sector number of an fnode */
typedef secno anode_secno; /* sector number of an anode */
typedef u32 time32_t; /* 32-bit time_t type */
/* sector 0 */
/* The boot block is very like a FAT boot block, except that the
29h signature byte is 28h instead, and the ID string is "HPFS". */
#define BB_MAGIC 0xaa55
struct hpfs_boot_block
{
u8 jmp[3];
u8 oem_id[8];
u8 bytes_per_sector[2]; /* 512 */
u8 sectors_per_cluster;
u8 n_reserved_sectors[2];
u8 n_fats;
u8 n_rootdir_entries[2];
u8 n_sectors_s[2];
u8 media_byte;
u16 sectors_per_fat;
u16 sectors_per_track;
u16 heads_per_cyl;
u32 n_hidden_sectors;
u32 n_sectors_l; /* size of partition */
u8 drive_number;
u8 mbz;
u8 sig_28h; /* 28h */
u8 vol_serno[4];
u8 vol_label[11];
u8 sig_hpfs[8]; /* "HPFS " */
u8 pad[448];
u16 magic; /* aa55 */
};
/* sector 16 */
/* The super block has the pointer to the root directory. */
#define SB_MAGIC 0xf995e849
struct hpfs_super_block
{
u32 magic; /* f995 e849 */
u32 magic1; /* fa53 e9c5, more magic? */
u8 version; /* version of a filesystem usually 2 */
u8 funcversion; /* functional version - oldest version
of filesystem that can understand
this disk */
u16 zero; /* 0 */
fnode_secno root; /* fnode of root directory */
secno n_sectors; /* size of filesystem */
u32 n_badblocks; /* number of bad blocks */
secno bitmaps; /* pointers to free space bit maps */
u32 zero1; /* 0 */
secno badblocks; /* bad block list */
u32 zero3; /* 0 */
time32_t last_chkdsk; /* date last checked, 0 if never */
time32_t last_optimize; /* date last optimized, 0 if never */
secno n_dir_band; /* number of sectors in dir band */
secno dir_band_start; /* first sector in dir band */
secno dir_band_end; /* last sector in dir band */
secno dir_band_bitmap; /* free space map, 1 dnode per bit */
u8 volume_name[32]; /* not used */
secno user_id_table; /* 8 preallocated sectors - user id */
u32 zero6[103]; /* 0 */
};
/* sector 17 */
/* The spare block has pointers to spare sectors. */
#define SP_MAGIC 0xf9911849
struct hpfs_spare_block
{
u32 magic; /* f991 1849 */
u32 magic1; /* fa52 29c5, more magic? */
#ifdef __LITTLE_ENDIAN
u8 dirty: 1; /* 0 clean, 1 "improperly stopped" */
u8 sparedir_used: 1; /* spare dirblks used */
u8 hotfixes_used: 1; /* hotfixes used */
u8 bad_sector: 1; /* bad sector, corrupted disk (???) */
u8 bad_bitmap: 1; /* bad bitmap */
u8 fast: 1; /* partition was fast formatted */
u8 old_wrote: 1; /* old version wrote to partion */
u8 old_wrote_1: 1; /* old version wrote to partion (?) */
#else
u8 old_wrote_1: 1; /* old version wrote to partion (?) */
u8 old_wrote: 1; /* old version wrote to partion */
u8 fast: 1; /* partition was fast formatted */
u8 bad_bitmap: 1; /* bad bitmap */
u8 bad_sector: 1; /* bad sector, corrupted disk (???) */
u8 hotfixes_used: 1; /* hotfixes used */
u8 sparedir_used: 1; /* spare dirblks used */
u8 dirty: 1; /* 0 clean, 1 "improperly stopped" */
#endif
#ifdef __LITTLE_ENDIAN
u8 install_dasd_limits: 1; /* HPFS386 flags */
u8 resynch_dasd_limits: 1;
u8 dasd_limits_operational: 1;
u8 multimedia_active: 1;
u8 dce_acls_active: 1;
u8 dasd_limits_dirty: 1;
u8 flag67: 2;
#else
u8 flag67: 2;
u8 dasd_limits_dirty: 1;
u8 dce_acls_active: 1;
u8 multimedia_active: 1;
u8 dasd_limits_operational: 1;
u8 resynch_dasd_limits: 1;
u8 install_dasd_limits: 1; /* HPFS386 flags */
#endif
u8 mm_contlgulty;
u8 unused;
secno hotfix_map; /* info about remapped bad sectors */
u32 n_spares_used; /* number of hotfixes */
u32 n_spares; /* number of spares in hotfix map */
u32 n_dnode_spares_free; /* spare dnodes unused */
u32 n_dnode_spares; /* length of spare_dnodes[] list,
follows in this block*/
secno code_page_dir; /* code page directory block */
u32 n_code_pages; /* number of code pages */
u32 super_crc; /* on HPFS386 and LAN Server this is
checksum of superblock, on normal
OS/2 unused */
u32 spare_crc; /* on HPFS386 checksum of spareblock */
u32 zero1[15]; /* unused */
dnode_secno spare_dnodes[100]; /* emergency free dnode list */
u32 zero2[1]; /* room for more? */
};
/* The bad block list is 4 sectors long. The first word must be zero,
the remaining words give n_badblocks bad block numbers.
I bet you can see it coming... */
#define BAD_MAGIC 0
/* The hotfix map is 4 sectors long. It looks like
secno from[n_spares];
secno to[n_spares];
The to[] list is initialized to point to n_spares preallocated empty
sectors. The from[] list contains the sector numbers of bad blocks
which have been remapped to corresponding sectors in the to[] list.
n_spares_used gives the length of the from[] list. */
/* Sectors 18 and 19 are preallocated and unused.
Maybe they're spares for 16 and 17, but simple substitution fails. */
/* The code page info pointed to by the spare block consists of an index
block and blocks containing uppercasing tables. I don't know what
these are for (CHKDSK, maybe?) -- OS/2 does not seem to use them
itself. Linux doesn't use them either. */
/* block pointed to by spareblock->code_page_dir */
#define CP_DIR_MAGIC 0x494521f7
struct code_page_directory
{
u32 magic; /* 4945 21f7 */
u32 n_code_pages; /* number of pointers following */
u32 zero1[2];
struct {
u16 ix; /* index */
u16 code_page_number; /* code page number */
u32 bounds; /* matches corresponding word
in data block */
secno code_page_data; /* sector number of a code_page_data
containing c.p. array */
u16 index; /* index in c.p. array in that sector*/
u16 unknown; /* some unknown value; usually 0;
2 in Japanese version */
} array[31]; /* unknown length */
};
/* blocks pointed to by code_page_directory */
#define CP_DATA_MAGIC 0x894521f7
struct code_page_data
{
u32 magic; /* 8945 21f7 */
u32 n_used; /* # elements used in c_p_data[] */
u32 bounds[3]; /* looks a bit like
(beg1,end1), (beg2,end2)
one byte each */
u16 offs[3]; /* offsets from start of sector
to start of c_p_data[ix] */
struct {
u16 ix; /* index */
u16 code_page_number; /* code page number */
u16 unknown; /* the same as in cp directory */
u8 map[128]; /* upcase table for chars 80..ff */
u16 zero2;
} code_page[3];
u8 incognita[78];
};
/* Free space bitmaps are 4 sectors long, which is 16384 bits.
16384 sectors is 8 meg, and each 8 meg band has a 4-sector bitmap.
Bit order in the maps is little-endian. 0 means taken, 1 means free.
Bit map sectors are marked allocated in the bit maps, and so are sectors
off the end of the partition.
Band 0 is sectors 0-3fff, its map is in sectors 18-1b.
Band 1 is 4000-7fff, its map is in 7ffc-7fff.
Band 2 is 8000-ffff, its map is in 8000-8003.
The remaining bands have maps in their first (even) or last (odd) 4 sectors
-- if the last, partial, band is odd its map is in its last 4 sectors.
The bitmap locations are given in a table pointed to by the super block.
No doubt they aren't constrained to be at 18, 7ffc, 8000, ...; that is
just where they usually are.
The "directory band" is a bunch of sectors preallocated for dnodes.
It has a 4-sector free space bitmap of its own. Each bit in the map
corresponds to one 4-sector dnode, bit 0 of the map corresponding to
the first 4 sectors of the directory band. The entire band is marked
allocated in the main bitmap. The super block gives the locations
of the directory band and its bitmap. ("band" doesn't mean it is
8 meg long; it isn't.) */
/* dnode: directory. 4 sectors long */
/* A directory is a tree of dnodes. The fnode for a directory
contains one pointer, to the root dnode of the tree. The fnode
never moves, the dnodes do the B-tree thing, splitting and merging
as files are added and removed. */
#define DNODE_MAGIC 0x77e40aae
struct dnode {
u32 magic; /* 77e4 0aae */
u32 first_free; /* offset from start of dnode to
first free dir entry */
#ifdef __LITTLE_ENDIAN
u8 root_dnode: 1; /* Is it root dnode? */
u8 increment_me: 7; /* some kind of activity counter? */
/* Neither HPFS.IFS nor CHKDSK cares
if you change this word */
#else
u8 increment_me: 7; /* some kind of activity counter? */
/* Neither HPFS.IFS nor CHKDSK cares
if you change this word */
u8 root_dnode: 1; /* Is it root dnode? */
#endif
u8 increment_me2[3];
secno up; /* (root dnode) directory's fnode
(nonroot) parent dnode */
dnode_secno self; /* pointer to this dnode */
u8 dirent[2028]; /* one or more dirents */
};
struct hpfs_dirent {
u16 length; /* offset to next dirent */
#ifdef __LITTLE_ENDIAN
u8 first: 1; /* set on phony ^A^A (".") entry */
u8 has_acl: 1;
u8 down: 1; /* down pointer present (after name) */
u8 last: 1; /* set on phony \377 entry */
u8 has_ea: 1; /* entry has EA */
u8 has_xtd_perm: 1; /* has extended perm list (???) */
u8 has_explicit_acl: 1;
u8 has_needea: 1; /* ?? some EA has NEEDEA set
I have no idea why this is
interesting in a dir entry */
#else
u8 has_needea: 1; /* ?? some EA has NEEDEA set
I have no idea why this is
interesting in a dir entry */
u8 has_explicit_acl: 1;
u8 has_xtd_perm: 1; /* has extended perm list (???) */
u8 has_ea: 1; /* entry has EA */
u8 last: 1; /* set on phony \377 entry */
u8 down: 1; /* down pointer present (after name) */
u8 has_acl: 1;
u8 first: 1; /* set on phony ^A^A (".") entry */
#endif
#ifdef __LITTLE_ENDIAN
u8 read_only: 1; /* dos attrib */
u8 hidden: 1; /* dos attrib */
u8 system: 1; /* dos attrib */
u8 flag11: 1; /* would be volume label dos attrib */
u8 directory: 1; /* dos attrib */
u8 archive: 1; /* dos attrib */
u8 not_8x3: 1; /* name is not 8.3 */
u8 flag15: 1;
#else
u8 flag15: 1;
u8 not_8x3: 1; /* name is not 8.3 */
u8 archive: 1; /* dos attrib */
u8 directory: 1; /* dos attrib */
u8 flag11: 1; /* would be volume label dos attrib */
u8 system: 1; /* dos attrib */
u8 hidden: 1; /* dos attrib */
u8 read_only: 1; /* dos attrib */
#endif
fnode_secno fnode; /* fnode giving allocation info */
time32_t write_date; /* mtime */
u32 file_size; /* file length, bytes */
time32_t read_date; /* atime */
time32_t creation_date; /* ctime */
u32 ea_size; /* total EA length, bytes */
u8 no_of_acls; /* number of ACL's (low 3 bits) */
u8 ix; /* code page index (of filename), see
struct code_page_data */
u8 namelen, name[1]; /* file name */
/* dnode_secno down; btree down pointer, if present,
follows name on next word boundary, or maybe it
precedes next dirent, which is on a word boundary. */
};
/* B+ tree: allocation info in fnodes and anodes */
/* dnodes point to fnodes which are responsible for listing the sectors
assigned to the file. This is done with trees of (length,address)
pairs. (Actually triples, of (length, file-address, disk-address)
which can represent holes. Find out if HPFS does that.)
At any rate, fnodes contain a small tree; if subtrees are needed
they occupy essentially a full block in anodes. A leaf-level tree node
has 3-word entries giving sector runs, a non-leaf node has 2-word
entries giving subtree pointers. A flag in the header says which. */
struct bplus_leaf_node
{
u32 file_secno; /* first file sector in extent */
u32 length; /* length, sectors */
secno disk_secno; /* first corresponding disk sector */
};
struct bplus_internal_node
{
u32 file_secno; /* subtree maps sectors < this */
anode_secno down; /* pointer to subtree */
};
struct bplus_header
{
#ifdef __LITTLE_ENDIAN
u8 hbff: 1; /* high bit of first free entry offset */
u8 flag1234: 4;
u8 fnode_parent: 1; /* ? we're pointed to by an fnode,
the data btree or some ea or the
main ea bootage pointer ea_secno */
/* also can get set in fnodes, which
may be a chkdsk glitch or may mean
this bit is irrelevant in fnodes,
or this interpretation is all wet */
u8 binary_search: 1; /* suggest binary search (unused) */
u8 internal: 1; /* 1 -> (internal) tree of anodes
0 -> (leaf) list of extents */
#else
u8 internal: 1; /* 1 -> (internal) tree of anodes
0 -> (leaf) list of extents */
u8 binary_search: 1; /* suggest binary search (unused) */
u8 fnode_parent: 1; /* ? we're pointed to by an fnode,
the data btree or some ea or the
main ea bootage pointer ea_secno */
/* also can get set in fnodes, which
may be a chkdsk glitch or may mean
this bit is irrelevant in fnodes,
or this interpretation is all wet */
u8 flag1234: 4;
u8 hbff: 1; /* high bit of first free entry offset */
#endif
u8 fill[3];
u8 n_free_nodes; /* free nodes in following array */
u8 n_used_nodes; /* used nodes in following array */
u16 first_free; /* offset from start of header to
first free node in array */
union {
struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
subtree pointers */
struct bplus_leaf_node external[0]; /* (external) 3-word entries giving
sector runs */
} u;
};
/* fnode: root of allocation b+ tree, and EA's */
/* Every file and every directory has one fnode, pointed to by the directory
entry and pointing to the file's sectors or directory's root dnode. EA's
are also stored here, and there are said to be ACL's somewhere here too. */
#define FNODE_MAGIC 0xf7e40aae
struct fnode
{
u32 magic; /* f7e4 0aae */
u32 zero1[2]; /* read history */
u8 len, name[15]; /* true length, truncated name */
fnode_secno up; /* pointer to file's directory fnode */
secno acl_size_l;
secno acl_secno;
u16 acl_size_s;
u8 acl_anode;
u8 zero2; /* history bit count */
u32 ea_size_l; /* length of disk-resident ea's */
secno ea_secno; /* first sector of disk-resident ea's*/
u16 ea_size_s; /* length of fnode-resident ea's */
#ifdef __LITTLE_ENDIAN
u8 flag0: 1;
u8 ea_anode: 1; /* 1 -> ea_secno is an anode */
u8 flag234567: 6;
#else
u8 flag234567: 6;
u8 ea_anode: 1; /* 1 -> ea_secno is an anode */
u8 flag0: 1;
#endif
#ifdef __LITTLE_ENDIAN
u8 dirflag: 1; /* 1 -> directory. first & only extent
points to dnode. */
u8 flag9012345: 7;
#else
u8 flag9012345: 7;
u8 dirflag: 1; /* 1 -> directory. first & only extent
points to dnode. */
#endif
struct bplus_header btree; /* b+ tree, 8 extents or 12 subtrees */
union {
struct bplus_leaf_node external[8];
struct bplus_internal_node internal[12];
} u;
u32 file_size; /* file length, bytes */
u32 n_needea; /* number of EA's with NEEDEA set */
u8 user_id[16]; /* unused */
u16 ea_offs; /* offset from start of fnode
to first fnode-resident ea */
u8 dasd_limit_treshhold;
u8 dasd_limit_delta;
u32 dasd_limit;
u32 dasd_usage;
u8 ea[316]; /* zero or more EA's, packed together
with no alignment padding.
(Do not use this name, get here
via fnode + ea_offs. I think.) */
};
/* anode: 99.44% pure allocation tree */
#define ANODE_MAGIC 0x37e40aae
struct anode
{
u32 magic; /* 37e4 0aae */
anode_secno self; /* pointer to this anode */
secno up; /* parent anode or fnode */
struct bplus_header btree; /* b+tree, 40 extents or 60 subtrees */
union {
struct bplus_leaf_node external[40];
struct bplus_internal_node internal[60];
} u;
u32 fill[3]; /* unused */
};
/* extended attributes.
A file's EA info is stored as a list of (name,value) pairs. It is
usually in the fnode, but (if it's large) it is moved to a single
sector run outside the fnode, or to multiple runs with an anode tree
that points to them.
The value of a single EA is stored along with the name, or (if large)
it is moved to a single sector run, or multiple runs pointed to by an
anode tree, pointed to by the value field of the (name,value) pair.
Flags in the EA tell whether the value is immediate, in a single sector
run, or in multiple runs. Flags in the fnode tell whether the EA list
is immediate, in a single run, or in multiple runs. */
struct extended_attribute
{
#ifdef __LITTLE_ENDIAN
u8 indirect: 1; /* 1 -> value gives sector number
where real value starts */
u8 anode: 1; /* 1 -> sector is an anode
that points to fragmented value */
u8 flag23456: 5;
u8 needea: 1; /* required ea */
#else
u8 needea: 1; /* required ea */
u8 flag23456: 5;
u8 anode: 1; /* 1 -> sector is an anode
that points to fragmented value */
u8 indirect: 1; /* 1 -> value gives sector number
where real value starts */
#endif
u8 namelen; /* length of name, bytes */
u8 valuelen_lo; /* length of value, bytes */
u8 valuelen_hi; /* length of value, bytes */
u8 name[0];
/*
u8 name[namelen]; ascii attrib name
u8 nul; terminating '\0', not counted
u8 value[valuelen]; value, arbitrary
if this.indirect, valuelen is 8 and the value is
u32 length; real length of value, bytes
secno secno; sector address where it starts
if this.anode, the above sector number is the root of an anode tree
which points to the value.
*/
};
/*
Local Variables:
comment-column: 40
End:
*/
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