- 根目录:
- fs
- xfs
- xfs_dir2_format.h
/*
* Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_DIR2_FORMAT_H__
#define __XFS_DIR2_FORMAT_H__
/*
* Directory version 2.
*
* There are 4 possible formats:
* - shortform - embedded into the inode
* - single block - data with embedded leaf at the end
* - multiple data blocks, single leaf+freeindex block
* - data blocks, node and leaf blocks (btree), freeindex blocks
*
* Note: many node blocks structures and constants are shared with the attr
* code and defined in xfs_da_btree.h.
*/
#define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */
#define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */
#define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */
/*
* Byte offset in data block and shortform entry.
*/
typedef __uint16_t xfs_dir2_data_off_t;
#define NULLDATAOFF 0xffffU
typedef uint xfs_dir2_data_aoff_t; /* argument form */
/*
* Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
* Only need 16 bits, this is the byte offset into the single block form.
*/
typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
/*
* Offset in data space of a data entry.
*/
typedef __uint32_t xfs_dir2_dataptr_t;
#define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff)
#define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0)
/*
* Byte offset in a directory.
*/
typedef xfs_off_t xfs_dir2_off_t;
/*
* Directory block number (logical dirblk in file)
*/
typedef __uint32_t xfs_dir2_db_t;
/*
* Inode number stored as 8 8-bit values.
*/
typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
/*
* Inode number stored as 4 8-bit values.
* Works a lot of the time, when all the inode numbers in a directory
* fit in 32 bits.
*/
typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
typedef union {
xfs_dir2_ino8_t i8;
xfs_dir2_ino4_t i4;
} xfs_dir2_inou_t;
#define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
/*
* Directory layout when stored internal to an inode.
*
* Small directories are packed as tightly as possible so as to fit into the
* literal area of the inode. These "shortform" directories consist of a
* single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
* structures. Due the different inode number storage size and the variable
* length name field in the xfs_dir2_sf_entry all these structure are
* variable length, and the accessors in this file should be used to iterate
* over them.
*/
typedef struct xfs_dir2_sf_hdr {
__uint8_t count; /* count of entries */
__uint8_t i8count; /* count of 8-byte inode #s */
xfs_dir2_inou_t parent; /* parent dir inode number */
} __arch_pack xfs_dir2_sf_hdr_t;
typedef struct xfs_dir2_sf_entry {
__u8 namelen; /* actual name length */
xfs_dir2_sf_off_t offset; /* saved offset */
__u8 name[]; /* name, variable size */
/*
* A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
* variable offset after the name.
*/
} __arch_pack xfs_dir2_sf_entry_t;
static inline int xfs_dir2_sf_hdr_size(int i8count)
{
return sizeof(struct xfs_dir2_sf_hdr) -
(i8count == 0) *
(sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t));
}
static inline xfs_dir2_data_aoff_t
xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
{
return get_unaligned_be16(&sfep->offset.i);
}
static inline void
xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
{
put_unaligned_be16(off, &sfep->offset.i);
}
static inline int
xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len)
{
return sizeof(struct xfs_dir2_sf_entry) + /* namelen + offset */
len + /* name */
(hdr->i8count ? /* ino */
sizeof(xfs_dir2_ino8_t) :
sizeof(xfs_dir2_ino4_t));
}
static inline struct xfs_dir2_sf_entry *
xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
{
return (struct xfs_dir2_sf_entry *)
((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
}
static inline struct xfs_dir2_sf_entry *
xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
struct xfs_dir2_sf_entry *sfep)
{
return (struct xfs_dir2_sf_entry *)
((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
}
/*
* Data block structures.
*
* A pure data block looks like the following drawing on disk:
*
* +-------------------------------------------------+
* | xfs_dir2_data_hdr_t |
* +-------------------------------------------------+
* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
* | ... |
* +-------------------------------------------------+
* | unused space |
* +-------------------------------------------------+
*
* As all the entries are variable size structures the accessors below should
* be used to iterate over them.
*
* In addition to the pure data blocks for the data and node formats,
* most structures are also used for the combined data/freespace "block"
* format below.
*/
#define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */
#define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG)
#define XFS_DIR2_DATA_FREE_TAG 0xffff
#define XFS_DIR2_DATA_FD_COUNT 3
/*
* Directory address space divided into sections,
* spaces separated by 32GB.
*/
#define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
#define XFS_DIR2_DATA_SPACE 0
#define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_DATA_FIRSTDB(mp) \
xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
/*
* Offsets of . and .. in data space (always block 0)
*/
#define XFS_DIR2_DATA_DOT_OFFSET \
((xfs_dir2_data_aoff_t)sizeof(struct xfs_dir2_data_hdr))
#define XFS_DIR2_DATA_DOTDOT_OFFSET \
(XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
#define XFS_DIR2_DATA_FIRST_OFFSET \
(XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))
/*
* Describe a free area in the data block.
*
* The freespace will be formatted as a xfs_dir2_data_unused_t.
*/
typedef struct xfs_dir2_data_free {
__be16 offset; /* start of freespace */
__be16 length; /* length of freespace */
} xfs_dir2_data_free_t;
/*
* Header for the data blocks.
*
* The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
*/
typedef struct xfs_dir2_data_hdr {
__be32 magic; /* XFS_DIR2_DATA_MAGIC or */
/* XFS_DIR2_BLOCK_MAGIC */
xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
} xfs_dir2_data_hdr_t;
/*
* Active entry in a data block.
*
* Aligned to 8 bytes. After the variable length name field there is a
* 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p.
*/
typedef struct xfs_dir2_data_entry {
__be64 inumber; /* inode number */
__u8 namelen; /* name length */
__u8 name[]; /* name bytes, no null */
/* __be16 tag; */ /* starting offset of us */
} xfs_dir2_data_entry_t;
/*
* Unused entry in a data block.
*
* Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed
* using xfs_dir2_data_unused_tag_p.
*/
typedef struct xfs_dir2_data_unused {
__be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */
__be16 length; /* total free length */
/* variable offset */
__be16 tag; /* starting offset of us */
} xfs_dir2_data_unused_t;
/*
* Size of a data entry.
*/
static inline int xfs_dir2_data_entsize(int n)
{
return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n +
(uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
}
/*
* Pointer to an entry's tag word.
*/
static inline __be16 *
xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep)
{
return (__be16 *)((char *)dep +
xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
}
/*
* Pointer to a freespace's tag word.
*/
static inline __be16 *
xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
{
return (__be16 *)((char *)dup +
be16_to_cpu(dup->length) - sizeof(__be16));
}
/*
* Leaf block structures.
*
* A pure leaf block looks like the following drawing on disk:
*
* +---------------------------+
* | xfs_dir2_leaf_hdr_t |
* +---------------------------+
* | xfs_dir2_leaf_entry_t |
* | xfs_dir2_leaf_entry_t |
* | xfs_dir2_leaf_entry_t |
* | xfs_dir2_leaf_entry_t |
* | ... |
* +---------------------------+
* | xfs_dir2_data_off_t |
* | xfs_dir2_data_off_t |
* | xfs_dir2_data_off_t |
* | ... |
* +---------------------------+
* | xfs_dir2_leaf_tail_t |
* +---------------------------+
*
* The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
* for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
* for directories with separate leaf nodes and free space blocks
* (magic = XFS_DIR2_LEAFN_MAGIC).
*
* As all the entries are variable size structures the accessors below should
* be used to iterate over them.
*/
/*
* Offset of the leaf/node space. First block in this space
* is the btree root.
*/
#define XFS_DIR2_LEAF_SPACE 1
#define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_LEAF_FIRSTDB(mp) \
xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)
/*
* Leaf block header.
*/
typedef struct xfs_dir2_leaf_hdr {
xfs_da_blkinfo_t info; /* header for da routines */
__be16 count; /* count of entries */
__be16 stale; /* count of stale entries */
} xfs_dir2_leaf_hdr_t;
/*
* Leaf block entry.
*/
typedef struct xfs_dir2_leaf_entry {
__be32 hashval; /* hash value of name */
__be32 address; /* address of data entry */
} xfs_dir2_leaf_entry_t;
/*
* Leaf block tail.
*/
typedef struct xfs_dir2_leaf_tail {
__be32 bestcount;
} xfs_dir2_leaf_tail_t;
/*
* Leaf block.
*/
typedef struct xfs_dir2_leaf {
xfs_dir2_leaf_hdr_t hdr; /* leaf header */
xfs_dir2_leaf_entry_t ents[]; /* entries */
} xfs_dir2_leaf_t;
/*
* DB blocks here are logical directory block numbers, not filesystem blocks.
*/
static inline int xfs_dir2_max_leaf_ents(struct xfs_mount *mp)
{
return (mp->m_dirblksize - (uint)sizeof(struct xfs_dir2_leaf_hdr)) /
(uint)sizeof(struct xfs_dir2_leaf_entry);
}
/*
* Get address of the bestcount field in the single-leaf block.
*/
static inline struct xfs_dir2_leaf_tail *
xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
{
return (struct xfs_dir2_leaf_tail *)
((char *)lp + mp->m_dirblksize -
sizeof(struct xfs_dir2_leaf_tail));
}
/*
* Get address of the bests array in the single-leaf block.
*/
static inline __be16 *
xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
{
return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
}
/*
* Convert dataptr to byte in file space
*/
static inline xfs_dir2_off_t
xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
}
/*
* Convert byte in file space to dataptr. It had better be aligned.
*/
static inline xfs_dir2_dataptr_t
xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
}
/*
* Convert byte in space to (DB) block
*/
static inline xfs_dir2_db_t
xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return (xfs_dir2_db_t)
(by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
}
/*
* Convert dataptr to a block number
*/
static inline xfs_dir2_db_t
xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
}
/*
* Convert byte in space to offset in a block
*/
static inline xfs_dir2_data_aoff_t
xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return (xfs_dir2_data_aoff_t)(by &
((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
}
/*
* Convert dataptr to a byte offset in a block
*/
static inline xfs_dir2_data_aoff_t
xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
{
return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
}
/*
* Convert block and offset to byte in space
*/
static inline xfs_dir2_off_t
xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
xfs_dir2_data_aoff_t o)
{
return ((xfs_dir2_off_t)db <<
(mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
}
/*
* Convert block (DB) to block (dablk)
*/
static inline xfs_dablk_t
xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
{
return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
}
/*
* Convert byte in space to (DA) block
*/
static inline xfs_dablk_t
xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
{
return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));
}
/*
* Convert block and offset to dataptr
*/
static inline xfs_dir2_dataptr_t
xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db,
xfs_dir2_data_aoff_t o)
{
return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o));
}
/*
* Convert block (dablk) to block (DB)
*/
static inline xfs_dir2_db_t
xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da)
{
return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog);
}
/*
* Convert block (dablk) to byte offset in space
*/
static inline xfs_dir2_off_t
xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da)
{
return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0);
}
/*
* Free space block defintions for the node format.
*/
/*
* Offset of the freespace index.
*/
#define XFS_DIR2_FREE_SPACE 2
#define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_FREE_FIRSTDB(mp) \
xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET)
typedef struct xfs_dir2_free_hdr {
__be32 magic; /* XFS_DIR2_FREE_MAGIC */
__be32 firstdb; /* db of first entry */
__be32 nvalid; /* count of valid entries */
__be32 nused; /* count of used entries */
} xfs_dir2_free_hdr_t;
typedef struct xfs_dir2_free {
xfs_dir2_free_hdr_t hdr; /* block header */
__be16 bests[]; /* best free counts */
/* unused entries are -1 */
} xfs_dir2_free_t;
static inline int xfs_dir2_free_max_bests(struct xfs_mount *mp)
{
return (mp->m_dirblksize - sizeof(struct xfs_dir2_free_hdr)) /
sizeof(xfs_dir2_data_off_t);
}
/*
* Convert data space db to the corresponding free db.
*/
static inline xfs_dir2_db_t
xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db)
{
return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir2_free_max_bests(mp);
}
/*
* Convert data space db to the corresponding index in a free db.
*/
static inline int
xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db)
{
return db % xfs_dir2_free_max_bests(mp);
}
/*
* Single block format.
*
* The single block format looks like the following drawing on disk:
*
* +-------------------------------------------------+
* | xfs_dir2_data_hdr_t |
* +-------------------------------------------------+
* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
* | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
* | ... |
* +-------------------------------------------------+
* | unused space |
* +-------------------------------------------------+
* | ... |
* | xfs_dir2_leaf_entry_t |
* | xfs_dir2_leaf_entry_t |
* +-------------------------------------------------+
* | xfs_dir2_block_tail_t |
* +-------------------------------------------------+
*
* As all the entries are variable size structures the accessors below should
* be used to iterate over them.
*/
typedef struct xfs_dir2_block_tail {
__be32 count; /* count of leaf entries */
__be32 stale; /* count of stale lf entries */
} xfs_dir2_block_tail_t;
/*
* Pointer to the leaf header embedded in a data block (1-block format)
*/
static inline struct xfs_dir2_block_tail *
xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr)
{
return ((struct xfs_dir2_block_tail *)
((char *)hdr + mp->m_dirblksize)) - 1;
}
/*
* Pointer to the leaf entries embedded in a data block (1-block format)
*/
static inline struct xfs_dir2_leaf_entry *
xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
{
return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
}
#endif /* __XFS_DIR2_FORMAT_H__ */