17d539f049
This patch adds a cache for the hash table to the directory code in order to help simplify the way in which the hash table is accessed. This is intended to be a first step towards introducing some performance improvements in the directory code. There are two follow ups that I'm hoping to see fairly shortly. One is to simplify the hash table reading code now that we always read the complete hash table, whether we want one entry or all of them. The other is to introduce readahead on the heads of the hash chains which are referred to from the table. The hash table is a maximum of 128k in size, so it is not worth trying to read it in small chunks. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
70 lines
2.3 KiB
C
70 lines
2.3 KiB
C
/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU General Public License version 2.
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*/
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#ifndef __DIR_DOT_H__
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#define __DIR_DOT_H__
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#include <linux/dcache.h>
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#include <linux/crc32.h>
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struct inode;
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struct gfs2_inode;
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struct gfs2_inum;
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extern struct inode *gfs2_dir_search(struct inode *dir,
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const struct qstr *filename);
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extern int gfs2_dir_check(struct inode *dir, const struct qstr *filename,
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const struct gfs2_inode *ip);
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extern int gfs2_dir_add(struct inode *inode, const struct qstr *filename,
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const struct gfs2_inode *ip);
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extern int gfs2_dir_del(struct gfs2_inode *dip, const struct dentry *dentry);
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extern int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
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filldir_t filldir);
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extern int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
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const struct gfs2_inode *nip, unsigned int new_type);
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extern int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip);
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extern int gfs2_diradd_alloc_required(struct inode *dir,
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const struct qstr *filename);
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extern int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,
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struct buffer_head **bhp);
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extern void gfs2_dir_hash_inval(struct gfs2_inode *ip);
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static inline u32 gfs2_disk_hash(const char *data, int len)
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{
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return crc32_le((u32)~0, data, len) ^ (u32)~0;
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}
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static inline void gfs2_str2qstr(struct qstr *name, const char *fname)
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{
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name->name = fname;
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name->len = strlen(fname);
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name->hash = gfs2_disk_hash(name->name, name->len);
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}
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/* N.B. This probably ought to take inum & type as args as well */
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static inline void gfs2_qstr2dirent(const struct qstr *name, u16 reclen, struct gfs2_dirent *dent)
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{
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dent->de_inum.no_addr = cpu_to_be64(0);
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dent->de_inum.no_formal_ino = cpu_to_be64(0);
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dent->de_hash = cpu_to_be32(name->hash);
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dent->de_rec_len = cpu_to_be16(reclen);
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dent->de_name_len = cpu_to_be16(name->len);
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dent->de_type = cpu_to_be16(0);
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memset(dent->__pad, 0, sizeof(dent->__pad));
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memcpy(dent + 1, name->name, name->len);
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}
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extern struct qstr gfs2_qdot;
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extern struct qstr gfs2_qdotdot;
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#endif /* __DIR_DOT_H__ */
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