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/*
* V9FS FID Management
*
* Copyright (C) 2005, 2006 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 version 2
* as published by the Free Software Foundation.
*
* 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/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/idr.h>
#include <asm/semaphore.h>
#include "debug.h"
#include "v9fs.h"
#include "9p.h"
#include "v9fs_vfs.h"
#include "fid.h"
/**
* v9fs_fid_insert - add a fid to a dentry
* @fid: fid to add
* @dentry: dentry that it is being added to
*
*/
int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
dentry->d_iname, dentry);
if (dentry->d_fsdata == NULL) {
dentry->d_fsdata =
kmalloc(sizeof(struct list_head), GFP_KERNEL);
if (dentry->d_fsdata == NULL) {
dprintk(DEBUG_ERROR, "Out of memory\n");
return -ENOMEM;
}
fid_list = (struct list_head *)dentry->d_fsdata;
INIT_LIST_HEAD(fid_list); /* Initialize list head */
}
fid->uid = current->uid;
list_add(&fid->list, fid_list);
return 0;
}
/**
* v9fs_fid_create - allocate a FID structure
* @dentry - dentry to link newly created fid to
*
*/
struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
{
struct v9fs_fid *new;
dprintk(DEBUG_9P, "fid create fid %d\n", fid);
new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
if (new == NULL) {
dprintk(DEBUG_ERROR, "Out of Memory\n");
return ERR_PTR(-ENOMEM);
}
new->fid = fid;
new->v9ses = v9ses;
new->fidopen = 0;
new->fidclunked = 0;
new->iounit = 0;
new->rdir_pos = 0;
new->rdir_fcall = NULL;
init_MUTEX(&new->lock);
INIT_LIST_HEAD(&new->list);
return new;
}
/**
* v9fs_fid_destroy - deallocate a FID structure
* @fid: fid to destroy
*
*/
void v9fs_fid_destroy(struct v9fs_fid *fid)
{
list_del(&fid->list);
kfree(fid);
}
/**
* v9fs_fid_lookup - return a locked fid from a dentry
* @dentry: dentry to look for fid in
*
* find a fid in the dentry, obtain its semaphore and return a reference to it.
* code calling lookup is responsible for releasing lock
*
* TODO: only match fids that have the same uid as current user
*
*/
struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
struct v9fs_fid *return_fid = NULL;
dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
if (fid_list)
return_fid = list_entry(fid_list->next, struct v9fs_fid, list);
if (!return_fid) {
dprintk(DEBUG_ERROR, "Couldn't find a fid in dentry\n");
return_fid = ERR_PTR(-EBADF);
}
if(down_interruptible(&return_fid->lock))
return ERR_PTR(-EINTR);
return return_fid;
}
/**
* v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and release it
* @dentry: dentry to look for fid in
*
* find a fid in the dentry and then clone to a new private fid
*
* TODO: only match fids that have the same uid as current user
*
*/
struct v9fs_fid *v9fs_fid_clone(struct dentry *dentry)
{
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
struct v9fs_fid *base_fid, *new_fid = ERR_PTR(-EBADF);
struct v9fs_fcall *fcall = NULL;
int fid, err;
base_fid = v9fs_fid_lookup(dentry);
if(IS_ERR(base_fid))
return base_fid;
if(base_fid) { /* clone fid */
fid = v9fs_get_idpool(&v9ses->fidpool);
if (fid < 0) {
eprintk(KERN_WARNING, "newfid fails!\n");
new_fid = ERR_PTR(-ENOSPC);
goto Release_Fid;
}
err = v9fs_t_walk(v9ses, base_fid->fid, fid, NULL, &fcall);
if (err < 0) {
dprintk(DEBUG_ERROR, "clone walk didn't work\n");
v9fs_put_idpool(fid, &v9ses->fidpool);
new_fid = ERR_PTR(err);
goto Free_Fcall;
}
new_fid = v9fs_fid_create(v9ses, fid);
if (new_fid == NULL) {
dprintk(DEBUG_ERROR, "out of memory\n");
new_fid = ERR_PTR(-ENOMEM);
}
Free_Fcall:
kfree(fcall);
}
Release_Fid:
up(&base_fid->lock);
return new_fid;
}
void v9fs_fid_clunk(struct v9fs_session_info *v9ses, struct v9fs_fid *fid)
{
v9fs_t_clunk(v9ses, fid->fid);
v9fs_fid_destroy(fid);
}
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