kernel-ark/fs/9p/fid.h
Latchesar Ionkov 0b8dd17762 [PATCH] v9fs: fix races in fid allocation
Fid management cleanup.  The patch attempts to fix the races in dentry's
fid management.

Dentries don't keep the opened fids anymore, they are moved to the file
structs.  Ideally there should be no more than one fid with fidcreate equal
to zero in the dentry's list of fids.

v9fs_fid_create initializes the important fields (fid, fidcreated) before
v9fs_fid is added to the list.  v9fs_fid_lookup returns only fids that are
not created by v9fs_create.  v9fs_fid_get_created returns the fid created
by the same process by v9fs_create (if any) and removes it from dentry's
list

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-28 07:46:40 -07:00

61 lines
1.9 KiB
C

/*
* V9FS FID Management
*
* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/list.h>
#define FID_OP 0
#define FID_WALK 1
#define FID_CREATE 2
struct v9fs_fid {
struct list_head list; /* list of fids associated with a dentry */
struct list_head active; /* XXX - debug */
u32 fid;
unsigned char fidopen; /* set when fid is opened */
unsigned char fidcreate; /* set when fid was just created */
unsigned char fidclunked; /* set when fid has already been clunked */
struct v9fs_qid qid;
u32 iounit;
/* readdir stuff */
int rdir_fpos;
loff_t rdir_pos;
struct v9fs_fcall *rdir_fcall;
/* management stuff */
pid_t pid; /* thread associated with this fid */
uid_t uid; /* user associated with this fid */
/* private data */
struct file *filp; /* backpointer to File struct for open files */
struct v9fs_session_info *v9ses; /* session info for this FID */
};
struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry);
struct v9fs_fid *v9fs_fid_get_created(struct dentry *);
void v9fs_fid_destroy(struct v9fs_fid *fid);
struct v9fs_fid *v9fs_fid_create(struct dentry *,
struct v9fs_session_info *v9ses, int fid, int create);