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