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aha/include/linux/gfs2_ondisk.h
Steven Whitehouse b6ed2e03df GFS2: Add explanation of extended attr on-disk format 
Some useful info regarding the on-disk representation of
GFS2 extended attributes.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-08-25 13:44:04 +01:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#ifndef __GFS2_ONDISK_DOT_H__
#define __GFS2_ONDISK_DOT_H__
#include <linux/types.h>
#define GFS2_MAGIC 0x01161970
#define GFS2_BASIC_BLOCK 512
#define GFS2_BASIC_BLOCK_SHIFT 9
/* Lock numbers of the LM_TYPE_NONDISK type */
#define GFS2_MOUNT_LOCK 0
#define GFS2_LIVE_LOCK 1
#define GFS2_TRANS_LOCK 2
#define GFS2_RENAME_LOCK 3
/* Format numbers for various metadata types */
#define GFS2_FORMAT_NONE 0
#define GFS2_FORMAT_SB 100
#define GFS2_FORMAT_RG 200
#define GFS2_FORMAT_RB 300
#define GFS2_FORMAT_DI 400
#define GFS2_FORMAT_IN 500
#define GFS2_FORMAT_LF 600
#define GFS2_FORMAT_JD 700
#define GFS2_FORMAT_LH 800
#define GFS2_FORMAT_LD 900
#define GFS2_FORMAT_LB 1000
#define GFS2_FORMAT_EA 1600
#define GFS2_FORMAT_ED 1700
#define GFS2_FORMAT_QC 1400
/* These are format numbers for entities contained in files */
#define GFS2_FORMAT_RI 1100
#define GFS2_FORMAT_DE 1200
#define GFS2_FORMAT_QU 1500
/* These are part of the superblock */
#define GFS2_FORMAT_FS 1801
#define GFS2_FORMAT_MULTI 1900
/*
* An on-disk inode number
*/
struct gfs2_inum {
__be64 no_formal_ino;
__be64 no_addr;
};
/*
* Generic metadata head structure
* Every inplace buffer logged in the journal must start with this.
*/
#define GFS2_METATYPE_NONE 0
#define GFS2_METATYPE_SB 1
#define GFS2_METATYPE_RG 2
#define GFS2_METATYPE_RB 3
#define GFS2_METATYPE_DI 4
#define GFS2_METATYPE_IN 5
#define GFS2_METATYPE_LF 6
#define GFS2_METATYPE_JD 7
#define GFS2_METATYPE_LH 8
#define GFS2_METATYPE_LD 9
#define GFS2_METATYPE_LB 12
#define GFS2_METATYPE_EA 10
#define GFS2_METATYPE_ED 11
#define GFS2_METATYPE_QC 14
struct gfs2_meta_header {
__be32 mh_magic;
__be32 mh_type;
__be64 __pad0; /* Was generation number in gfs1 */
__be32 mh_format;
__be32 __pad1; /* Was incarnation number in gfs1 */
};
/*
* super-block structure
*
* It's probably good if SIZEOF_SB <= GFS2_BASIC_BLOCK (512 bytes)
*
* Order is important, need to be able to read old superblocks to do on-disk
* version upgrades.
*/
/* Address of superblock in GFS2 basic blocks */
#define GFS2_SB_ADDR 128
/* The lock number for the superblock (must be zero) */
#define GFS2_SB_LOCK 0
/* Requirement: GFS2_LOCKNAME_LEN % 8 == 0
Includes: the fencing zero at the end */
#define GFS2_LOCKNAME_LEN 64
struct gfs2_sb {
struct gfs2_meta_header sb_header;
__be32 sb_fs_format;
__be32 sb_multihost_format;
__u32 __pad0; /* Was superblock flags in gfs1 */
__be32 sb_bsize;
__be32 sb_bsize_shift;
__u32 __pad1; /* Was journal segment size in gfs1 */
struct gfs2_inum sb_master_dir; /* Was jindex dinode in gfs1 */
struct gfs2_inum __pad2; /* Was rindex dinode in gfs1 */
struct gfs2_inum sb_root_dir;
char sb_lockproto[GFS2_LOCKNAME_LEN];
char sb_locktable[GFS2_LOCKNAME_LEN];
struct gfs2_inum __pad3; /* Was quota inode in gfs1 */
struct gfs2_inum __pad4; /* Was licence inode in gfs1 */
#define GFS2_HAS_UUID 1
__u8 sb_uuid[16]; /* The UUID, maybe 0 for backwards compat */
};
/*
* resource index structure
*/
struct gfs2_rindex {
__be64 ri_addr; /* grp block disk address */
__be32 ri_length; /* length of rgrp header in fs blocks */
__u32 __pad;
__be64 ri_data0; /* first data location */
__be32 ri_data; /* num of data blocks in rgrp */
__be32 ri_bitbytes; /* number of bytes in data bitmaps */
__u8 ri_reserved[64];
};
/*
* resource group header structure
*/
/* Number of blocks per byte in rgrp */
#define GFS2_NBBY 4
#define GFS2_BIT_SIZE 2
#define GFS2_BIT_MASK 0x00000003
#define GFS2_BLKST_FREE 0
#define GFS2_BLKST_USED 1
#define GFS2_BLKST_UNLINKED 2
#define GFS2_BLKST_DINODE 3
#define GFS2_RGF_JOURNAL 0x00000001
#define GFS2_RGF_METAONLY 0x00000002
#define GFS2_RGF_DATAONLY 0x00000004
#define GFS2_RGF_NOALLOC 0x00000008
struct gfs2_rgrp {
struct gfs2_meta_header rg_header;
__be32 rg_flags;
__be32 rg_free;
__be32 rg_dinodes;
__be32 __pad;
__be64 rg_igeneration;
__u8 rg_reserved[80]; /* Several fields from gfs1 now reserved */
};
/*
* quota linked list: user quotas and group quotas form two separate
* singly linked lists. ll_next stores uids or gids of next quotas in the
* linked list.
Given the uid/gid, how to calculate the quota file offsets for the corresponding
gfs2_quota structures on disk:
for user quotas, given uid,
offset = uid * sizeof(struct gfs2_quota);
for group quotas, given gid,
offset = (gid * sizeof(struct gfs2_quota)) + sizeof(struct gfs2_quota);
uid:0 gid:0 uid:12 gid:12 uid:17 gid:17 uid:5142 gid:5142
+-------+-------+ +-------+-------+ +-------+- - - -+ +- - - -+-------+
| valid | valid | :: | valid | valid | :: | valid | inval | :: | inval | valid |
+-------+-------+ +-------+-------+ +-------+- - - -+ +- - - -+-------+
next:12 next:12 next:17 next:5142 next:NULL next:NULL
| | | | |<-- user quota list |
\______|___________/ \______|___________/ group quota list -->|
| | |
\__________________/ \_______________________________________/
*/
/*
* quota structure
*/
struct gfs2_quota {
__be64 qu_limit;
__be64 qu_warn;
__be64 qu_value;
__be32 qu_ll_next; /* location of next quota in list */
__u8 qu_reserved[60];
};
/*
* dinode structure
*/
#define GFS2_MAX_META_HEIGHT 10
#define GFS2_DIR_MAX_DEPTH 17
#define DT2IF(dt) (((dt) << 12) & S_IFMT)
#define IF2DT(sif) (((sif) & S_IFMT) >> 12)
enum {
gfs2fl_Jdata = 0,
gfs2fl_ExHash = 1,
gfs2fl_Unused = 2,
gfs2fl_EaIndirect = 3,
gfs2fl_Directio = 4,
gfs2fl_Immutable = 5,
gfs2fl_AppendOnly = 6,
gfs2fl_NoAtime = 7,
gfs2fl_Sync = 8,
gfs2fl_System = 9,
gfs2fl_TruncInProg = 29,
gfs2fl_InheritDirectio = 30,
gfs2fl_InheritJdata = 31,
};
/* Dinode flags */
#define GFS2_DIF_JDATA 0x00000001
#define GFS2_DIF_EXHASH 0x00000002
#define GFS2_DIF_UNUSED 0x00000004 /* only in gfs1 */
#define GFS2_DIF_EA_INDIRECT 0x00000008
#define GFS2_DIF_DIRECTIO 0x00000010
#define GFS2_DIF_IMMUTABLE 0x00000020
#define GFS2_DIF_APPENDONLY 0x00000040
#define GFS2_DIF_NOATIME 0x00000080
#define GFS2_DIF_SYNC 0x00000100
#define GFS2_DIF_SYSTEM 0x00000200 /* New in gfs2 */
#define GFS2_DIF_TRUNC_IN_PROG 0x20000000 /* New in gfs2 */
#define GFS2_DIF_INHERIT_DIRECTIO 0x40000000
#define GFS2_DIF_INHERIT_JDATA 0x80000000
struct gfs2_dinode {
struct gfs2_meta_header di_header;
struct gfs2_inum di_num;
__be32 di_mode; /* mode of file */
__be32 di_uid; /* owner's user id */
__be32 di_gid; /* owner's group id */
__be32 di_nlink; /* number of links to this file */
__be64 di_size; /* number of bytes in file */
__be64 di_blocks; /* number of blocks in file */
__be64 di_atime; /* time last accessed */
__be64 di_mtime; /* time last modified */
__be64 di_ctime; /* time last changed */
__be32 di_major; /* device major number */
__be32 di_minor; /* device minor number */
/* This section varies from gfs1. Padding added to align with
* remainder of dinode
*/
__be64 di_goal_meta; /* rgrp to alloc from next */
__be64 di_goal_data; /* data block goal */
__be64 di_generation; /* generation number for NFS */
__be32 di_flags; /* GFS2_DIF_... */
__be32 di_payload_format; /* GFS2_FORMAT_... */
__u16 __pad1; /* Was ditype in gfs1 */
__be16 di_height; /* height of metadata */
__u32 __pad2; /* Unused incarnation number from gfs1 */
/* These only apply to directories */
__u16 __pad3; /* Padding */
__be16 di_depth; /* Number of bits in the table */
__be32 di_entries; /* The number of entries in the directory */
struct gfs2_inum __pad4; /* Unused even in current gfs1 */
__be64 di_eattr; /* extended attribute block number */
__be32 di_atime_nsec; /* nsec portion of atime */
__be32 di_mtime_nsec; /* nsec portion of mtime */
__be32 di_ctime_nsec; /* nsec portion of ctime */
__u8 di_reserved[44];
};
/*
* directory structure - many of these per directory file
*/
#define GFS2_FNAMESIZE 255
#define GFS2_DIRENT_SIZE(name_len) ((sizeof(struct gfs2_dirent) + (name_len) + 7) & ~7)
struct gfs2_dirent {
struct gfs2_inum de_inum;
__be32 de_hash;
__be16 de_rec_len;
__be16 de_name_len;
__be16 de_type;
__u8 __pad[14];
};
/*
* Header of leaf directory nodes
*/
struct gfs2_leaf {
struct gfs2_meta_header lf_header;
__be16 lf_depth; /* Depth of leaf */
__be16 lf_entries; /* Number of dirents in leaf */
__be32 lf_dirent_format; /* Format of the dirents */
__be64 lf_next; /* Next leaf, if overflow */
__u8 lf_reserved[64];
};
/*
* Extended attribute header format
*
* This works in a similar way to dirents. There is a fixed size header
* followed by a variable length section made up of the name and the
* associated data. In the case of a "stuffed" entry, the value is
* inline directly after the name, the ea_num_ptrs entry will be
* zero in that case. For non-"stuffed" entries, there will be
* a set of pointers (aligned to 8 byte boundary) to the block(s)
* containing the value.
*
* The blocks containing the values and the blocks containing the
* extended attribute headers themselves all start with the common
* metadata header. Each inode, if it has extended attributes, will
* have either a single block containing the extended attribute headers
* or a single indirect block pointing to blocks containing the
* extended attribure headers.
*
* The maximim size of the data part of an extended attribute is 64k
* so the number of blocks required depends upon block size. Since the
* block size also determines the number of pointers in an indirect
* block, its a fairly complicated calculation to work out the maximum
* number of blocks that an inode may have relating to extended attributes.
*
*/
#define GFS2_EA_MAX_NAME_LEN 255
#define GFS2_EA_MAX_DATA_LEN 65536
#define GFS2_EATYPE_UNUSED 0
#define GFS2_EATYPE_USR 1
#define GFS2_EATYPE_SYS 2
#define GFS2_EATYPE_SECURITY 3
#define GFS2_EATYPE_LAST 3
#define GFS2_EATYPE_VALID(x) ((x) <= GFS2_EATYPE_LAST)
#define GFS2_EAFLAG_LAST 0x01 /* last ea in block */
struct gfs2_ea_header {
__be32 ea_rec_len;
__be32 ea_data_len;
__u8 ea_name_len; /* no NULL pointer after the string */
__u8 ea_type; /* GFS2_EATYPE_... */
__u8 ea_flags; /* GFS2_EAFLAG_... */
__u8 ea_num_ptrs;
__u32 __pad;
};
/*
* Log header structure
*/
#define GFS2_LOG_HEAD_UNMOUNT 0x00000001 /* log is clean */
struct gfs2_log_header {
struct gfs2_meta_header lh_header;
__be64 lh_sequence; /* Sequence number of this transaction */
__be32 lh_flags; /* GFS2_LOG_HEAD_... */
__be32 lh_tail; /* Block number of log tail */
__be32 lh_blkno;
__be32 lh_hash;
};
/*
* Log type descriptor
*/
#define GFS2_LOG_DESC_METADATA 300
/* ld_data1 is the number of metadata blocks in the descriptor.
ld_data2 is unused. */
#define GFS2_LOG_DESC_REVOKE 301
/* ld_data1 is the number of revoke blocks in the descriptor.
ld_data2 is unused. */
#define GFS2_LOG_DESC_JDATA 302
/* ld_data1 is the number of data blocks in the descriptor.
ld_data2 is unused. */
struct gfs2_log_descriptor {
struct gfs2_meta_header ld_header;
__be32 ld_type; /* GFS2_LOG_DESC_... */
__be32 ld_length; /* Number of buffers in this chunk */
__be32 ld_data1; /* descriptor-specific field */
__be32 ld_data2; /* descriptor-specific field */
__u8 ld_reserved[32];
};
/*
* Inum Range
* Describe a range of formal inode numbers allocated to
* one machine to assign to inodes.
*/
#define GFS2_INUM_QUANTUM 1048576
struct gfs2_inum_range {
__be64 ir_start;
__be64 ir_length;
};
/*
* Statfs change
* Describes an change to the pool of free and allocated
* blocks.
*/
struct gfs2_statfs_change {
__be64 sc_total;
__be64 sc_free;
__be64 sc_dinodes;
};
/*
* Quota change
* Describes an allocation change for a particular
* user or group.
*/
#define GFS2_QCF_USER 0x00000001
struct gfs2_quota_change {
__be64 qc_change;
__be32 qc_flags; /* GFS2_QCF_... */
__be32 qc_id;
};
struct gfs2_quota_lvb {
__be32 qb_magic;
__u32 __pad;
__be64 qb_limit; /* Hard limit of # blocks to alloc */
__be64 qb_warn; /* Warn user when alloc is above this # */
__be64 qb_value; /* Current # blocks allocated */
};
#endif /* __GFS2_ONDISK_DOT_H__ */
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