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kernel-fxtec-pro1x/include/uapi/linux/gfs2_ondisk.h
Benjamin Marzinski 471f3db278 gfs2: change gfs2 readdir cookie 
gfs2 currently returns 31 bits of filename hash as a cookie that readdir
uses for an offset into the directory.  When there are a large number of
directory entries, the likelihood of a collision goes up way too
quickly.  GFS2 will now return cookies that are guaranteed unique for a
while, and then fail back to using 30 bits of filename hash.
Specifically, the directory leaf blocks are divided up into chunks based
on the minimum size of a gfs2 directory entry (48 bytes). Each entry's
cookie is based off the chunk where it starts, in the linked list of
leaf blocks that it hashes to (there are 131072 hash buckets). Directory
entries will have unique names until they take reach chunk 8192.
Assuming the largest filenames possible, and the least efficient spacing
possible, this new method will still be able to return unique names when
the previous method has statistically more than a 99% chance of a
collision.  The non-unique names it fails back to are guaranteed to not
collide with the unique names.

unique cookies will be in this format:
- 1 bit "0" to make sure the the returned cookie is positive
- 17 bits for the hash table index
- 1 bit for the mode "0"
- 13 bits for the offset

non-unique cookies will be in this format:
- 1 bit "0" to make sure the the returned cookie is positive
- 17 bits for the hash table index
- 1 bit for the mode "1"
- 13 more bits of the name hash

Another benefit of location based cookies, is that once a directory's
exhash table is fully extended (so that multiple hash table indexs do
not use the same leaf blocks), gfs2 can skip sorting the directory
entries until it reaches the non-unique ones, and then it only needs to
sort these. This provides a significant speed up for directory reads of
very large directories.

The only issue is that for these cookies to continue to point to the
correct entry as files are added and removed from the directory, gfs2
must keep the entries at the same offset in the leaf block when they are
split (see my previous patch). This means that until all the nodes in a
cluster are running with code that will split the directory leaf blocks
this way, none of the nodes can use the new cookie code. To deal with
this, gfs2 now has the mount option loccookie, which, if set, will make
it return these new location based cookies.  This option must not be set
until all nodes in the cluster are at least running this version of the
kernel code, and you have guaranteed that there are no outstanding
cookies required by other software, such as NFS.

gfs2 uses some of the extra space at the end of the gfs2_dirent
structure to store the calculated readdir cookies. This keeps us from
needing to allocate a seperate array to hold these values.  gfs2
recomputes the cookie stored in de_cookie for every readdir call.  The
time it takes to do so is small, and if gfs2 expected this value to be
saved on disk, the new code wouldn't work correctly on filesystems
created with an earlier version of gfs2.

One issue with adding de_cookie to the union in the gfs2_dirent
structure is that it caused the union to align itself to a 4 byte
boundary, instead of its previous 2 byte boundary. This changed the
offset of de_rahead. To solve that, I pulled de_rahead out of the union,
since it does not need to be there.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-12-14 12:19:37 -06:00

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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_FREEZE_LOCK 2
#define GFS2_RENAME_LOCK 3
#define GFS2_CONTROL_LOCK 4
#define GFS2_MOUNTED_LOCK 5
/* 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;
/* This union is to keep userspace happy */
union {
__be32 mh_jid; /* Was incarnation number in gfs1 */
__be32 __pad1;
};
};
/*
* 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
#define GFS2_RGF_TRIMMED 0x00000010
struct gfs2_rgrp_lvb {
__be32 rl_magic;
__be32 rl_flags;
__be32 rl_free;
__be32 rl_dinodes;
__be64 rl_igeneration;
__be32 rl_unlinked;
__be32 __pad;
};
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 structure
*/
struct gfs2_quota {
__be64 qu_limit;
__be64 qu_warn;
__be64 qu_value;
__u8 qu_reserved[64];
};
/*
* 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_TopLevel = 10,
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_TOPDIR 0x00000400 /* New in gfs2 */
#define GFS2_DIF_TRUNC_IN_PROG 0x20000000 /* New in gfs2 */
#define GFS2_DIF_INHERIT_DIRECTIO 0x40000000 /* only in gfs1 */
#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)
#define GFS2_MIN_DIRENT_SIZE (GFS2_DIRENT_SIZE(1))
struct gfs2_dirent {
struct gfs2_inum de_inum;
__be32 de_hash;
__be16 de_rec_len;
__be16 de_name_len;
__be16 de_type;
__be16 de_rahead;
union {
__u8 __pad[12];
struct {
__u32 de_cookie; /* ondisk value not used */
__u8 pad3[8];
};
};
};
/*
* 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 */
union {
__u8 lf_reserved[64];
struct {
__be64 lf_inode; /* Dir inode number */
__be32 lf_dist; /* Dist from inode on chain */
__be32 lf_nsec; /* Last ins/del usecs */
__be64 lf_sec; /* Last ins/del in secs */
__u8 lf_reserved2[40];
};
};
};
/*
* 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 attribute headers.
*
* The maximum 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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