freebsd-dev/sys/gnu/fs/ext2fs/inode.h
Ian Dowse 9b5ad47fb7 Bring in dirhash, a simple hash-based lookup optimisation for large
directories. When enabled via "options UFS_DIRHASH", in-core hash
arrays are maintained for large directories. These allow all
directory operations to take place quickly instead of requiring
long linear searches. For now anyway, dirhash is not enabled by
default.

The in-core hash arrays have a memory requirement that is approximately
half the size of the size of the on-disk directory file. A number
of new sysctl variables allow control over which directories get
hashed and over the maximum amount of memory that dirhash will use:

  vfs.ufs.dirhash_minsize
    The minimum on-disk directory size for which hashing should be
    used. The default is 2560 (2.5k).

  vfs.ufs.dirhash_maxmem
    The system-wide maximum total memory to be used by dirhash data
    structures. The default is 2097152 (2MB).

The current amount of memory being used by dirhash is visible
through the read-only sysctl variable vfs.ufs.dirhash_maxmem.
Finally, some extra sanity checks that are enabled by default, but
which may have an impact on performance, can be disabled by setting
vfs.ufs.dirhash_docheck to 0.

Discussed on: -fs, -hackers
2001-07-10 21:21:29 +00:00

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6.3 KiB
C

/*
* Copyright (c) 1982, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)inode.h 8.9 (Berkeley) 5/14/95
* $FreeBSD$
*/
#ifndef _UFS_UFS_INODE_H_
#define _UFS_UFS_INODE_H_
#include <sys/lock.h>
#include <sys/queue.h>
#include <ufs/ufs/dinode.h>
/*
* The size of a logical block number.
*/
typedef long ufs_lbn_t;
/*
* This must agree with the definition in <ufs/ufs/dir.h>.
*/
#define doff_t int32_t
/*
* The inode is used to describe each active (or recently active) file in the
* UFS filesystem. It is composed of two types of information. The first part
* is the information that is needed only while the file is active (such as
* the identity of the file and linkage to speed its lookup). The second part
* is the permanent meta-data associated with the file which is read in
* from the permanent dinode from long term storage when the file becomes
* active, and is put back when the file is no longer being used.
*/
struct inode {
LIST_ENTRY(inode) i_hash;/* Hash chain. */
TAILQ_ENTRY(inode) i_nextsnap; /* snapshot file list */
struct vnode *i_vnode;/* Vnode associated with this inode. */
struct vnode *i_devvp;/* Vnode for block I/O. */
u_int32_t i_flag; /* flags, see below */
dev_t i_dev; /* Device associated with the inode. */
ino_t i_number; /* The identity of the inode. */
int i_effnlink; /* i_nlink when I/O completes */
union { /* Associated filesystem. */
struct fs *fs; /* FFS */
struct ext2_sb_info *e2fs; /* EXT2FS */
} inode_u;
#define i_fs inode_u.fs
#define i_e2fs inode_u.e2fs
struct dquot *i_dquot[MAXQUOTAS]; /* Dquot structures. */
u_quad_t i_modrev; /* Revision level for NFS lease. */
struct lockf *i_lockf;/* Head of byte-level lock list. */
/*
* Side effects; used during directory lookup.
*/
int32_t i_count; /* Size of free slot in directory. */
doff_t i_endoff; /* End of useful stuff in directory. */
doff_t i_diroff; /* Offset in dir, where we found last entry. */
doff_t i_offset; /* Offset of free space in directory. */
ino_t i_ino; /* Inode number of found directory. */
u_int32_t i_reclen; /* Size of found directory entry. */
u_int32_t i_spare[4]; /* XXX actually non-spare (for ext2fs). */
struct dirhash *i_dirhash; /* Hashing for large directories */
/*
* The on-disk dinode itself.
*/
struct dinode i_din; /* 128 bytes of the on-disk dinode. */
};
#define i_atime i_din.di_atime
#define i_atimensec i_din.di_atimensec
#define i_blocks i_din.di_blocks
#define i_ctime i_din.di_ctime
#define i_ctimensec i_din.di_ctimensec
#define i_db i_din.di_db
#define i_flags i_din.di_flags
#define i_gen i_din.di_gen
#define i_gid i_din.di_gid
#define i_ib i_din.di_ib
#define i_mode i_din.di_mode
#define i_mtime i_din.di_mtime
#define i_mtimensec i_din.di_mtimensec
#define i_nlink i_din.di_nlink
#define i_rdev i_din.di_rdev
#define i_shortlink i_din.di_shortlink
#define i_size i_din.di_size
#define i_uid i_din.di_uid
/* These flags are kept in i_flag. */
#define IN_ACCESS 0x0001 /* Access time update request. */
#define IN_CHANGE 0x0002 /* Inode change time update request. */
#define IN_UPDATE 0x0004 /* Modification time update request. */
#define IN_MODIFIED 0x0008 /* Inode has been modified. */
#define IN_RENAME 0x0010 /* Inode is being renamed. */
#define IN_HASHED 0x0020 /* Inode is on hash list */
#define IN_LAZYMOD 0x0040 /* Modified, but don't write yet. */
#define IN_SPACECOUNTED 0x0080 /* Blocks to be freed in free count. */
#ifdef _KERNEL
/*
* Structure used to pass around logical block paths generated by
* ufs_getlbns and used by truncate and bmap code.
*/
struct indir {
ufs_daddr_t in_lbn; /* Logical block number. */
int in_off; /* Offset in buffer. */
int in_exists; /* Flag if the block exists. */
};
/* Convert between inode pointers and vnode pointers. */
#define VTOI(vp) ((struct inode *)(vp)->v_data)
#define ITOV(ip) ((ip)->i_vnode)
/* Determine if soft dependencies are being done */
#define DOINGSOFTDEP(vp) ((vp)->v_mount->mnt_flag & MNT_SOFTDEP)
#define DOINGASYNC(vp) ((vp)->v_mount->mnt_flag & MNT_ASYNC)
/* This overlays the fid structure (see mount.h). */
struct ufid {
u_int16_t ufid_len; /* Length of structure. */
u_int16_t ufid_pad; /* Force 32-bit alignment. */
ino_t ufid_ino; /* File number (ino). */
int32_t ufid_gen; /* Generation number. */
};
#endif /* _KERNEL */
#endif /* !_UFS_UFS_INODE_H_ */