alistair23-linux/fs/gfs2/dir.h
Steven Whitehouse 5a00f3cc97 GFS2: Only do one directory search on create
Creation of a new inode requires a directory search in order to ensure
that we are not trying to create an inode with the same name as an
existing one. This was hidden away inside the create_ok() function.

In the case that there was an existing inode, and a lookup can be
substituted for a create (which is the case with regular files
when the O_EXCL flag is not in use) then we were doing a second
lookup in order to return the inode.

This patch merges these two lookups into one. This can be done by
passing a flag to gfs2_dir_search() to tell it to just return -EEXIST
in the cases where we don't actually want to look up the inode.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2013-06-11 13:45:29 +01:00

71 lines
2.3 KiB
C

/*
* 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 version 2.
*/
#ifndef __DIR_DOT_H__
#define __DIR_DOT_H__
#include <linux/dcache.h>
#include <linux/crc32.h>
struct inode;
struct gfs2_inode;
struct gfs2_inum;
extern struct inode *gfs2_dir_search(struct inode *dir,
const struct qstr *filename,
bool fail_on_exist);
extern int gfs2_dir_check(struct inode *dir, const struct qstr *filename,
const struct gfs2_inode *ip);
extern int gfs2_dir_add(struct inode *inode, const struct qstr *filename,
const struct gfs2_inode *ip);
extern int gfs2_dir_del(struct gfs2_inode *dip, const struct dentry *dentry);
extern int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
filldir_t filldir, struct file_ra_state *f_ra);
extern int gfs2_dir_mvino(struct gfs2_inode *dip, const struct qstr *filename,
const struct gfs2_inode *nip, unsigned int new_type);
extern int gfs2_dir_exhash_dealloc(struct gfs2_inode *dip);
extern int gfs2_diradd_alloc_required(struct inode *dir,
const struct qstr *filename);
extern int gfs2_dir_get_new_buffer(struct gfs2_inode *ip, u64 block,
struct buffer_head **bhp);
extern void gfs2_dir_hash_inval(struct gfs2_inode *ip);
static inline u32 gfs2_disk_hash(const char *data, int len)
{
return crc32_le((u32)~0, data, len) ^ (u32)~0;
}
static inline void gfs2_str2qstr(struct qstr *name, const char *fname)
{
name->name = fname;
name->len = strlen(fname);
name->hash = gfs2_disk_hash(name->name, name->len);
}
/* N.B. This probably ought to take inum & type as args as well */
static inline void gfs2_qstr2dirent(const struct qstr *name, u16 reclen, struct gfs2_dirent *dent)
{
dent->de_inum.no_addr = cpu_to_be64(0);
dent->de_inum.no_formal_ino = cpu_to_be64(0);
dent->de_hash = cpu_to_be32(name->hash);
dent->de_rec_len = cpu_to_be16(reclen);
dent->de_name_len = cpu_to_be16(name->len);
dent->de_type = cpu_to_be16(0);
memset(dent->__pad, 0, sizeof(dent->__pad));
memcpy(dent + 1, name->name, name->len);
}
extern struct qstr gfs2_qdot;
extern struct qstr gfs2_qdotdot;
#endif /* __DIR_DOT_H__ */