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/*
* 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/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/idr.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
*
*/
static 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;
fid->pid = current->pid;
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 dentry *dentry,
struct v9fs_session_info *v9ses, int fid, int create)
{
struct v9fs_fid *new;
dprintk(DEBUG_9P, "fid create dentry %p, fid %d, create %d\n",
dentry, fid, create);
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->fidcreate = create;
new->fidclunked = 0;
new->iounit = 0;
new->rdir_pos = 0;
new->rdir_fcall = NULL;
if (v9fs_fid_insert(new, dentry) == 0)
return new;
else {
dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
kfree(new);
return NULL;
}
}
/**
* 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_walk_up - walks from the process current directory
* up to the specified dentry.
*/
static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
{
int fidnum, cfidnum, err;
struct v9fs_fid *cfid;
struct dentry *cde;
struct v9fs_session_info *v9ses;
v9ses = v9fs_inode2v9ses(current->fs->pwd->d_inode);
cfid = v9fs_fid_lookup(current->fs->pwd);
if (cfid == NULL) {
dprintk(DEBUG_ERROR, "process cwd doesn't have a fid\n");
return ERR_PTR(-ENOENT);
}
cfidnum = cfid->fid;
cde = current->fs->pwd;
/* TODO: take advantage of multiwalk */
fidnum = v9fs_get_idpool(&v9ses->fidpool);
if (fidnum < 0) {
dprintk(DEBUG_ERROR, "could not get a new fid num\n");
err = -ENOENT;
goto clunk_fid;
}
while (cde != dentry) {
if (cde == cde->d_parent) {
dprintk(DEBUG_ERROR, "can't find dentry\n");
err = -ENOENT;
goto clunk_fid;
}
err = v9fs_t_walk(v9ses, cfidnum, fidnum, "..", NULL);
if (err < 0) {
dprintk(DEBUG_ERROR, "problem walking to parent\n");
goto clunk_fid;
}
cfidnum = fidnum;
cde = cde->d_parent;
}
return v9fs_fid_create(dentry, v9ses, fidnum, 0);
clunk_fid:
v9fs_t_clunk(v9ses, fidnum);
return ERR_PTR(err);
}
/**
* v9fs_fid_lookup - retrieve the right fid from a particular dentry
* @dentry: dentry to look for fid in
* @type: intent of lookup (operation or traversal)
*
* search list of fids associated with a dentry for a fid with a matching
* thread id or uid. If that fails, look up the dentry's parents to see if you
* can find a matching fid.
*
*/
struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
{
struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
struct v9fs_fid *current_fid = NULL;
struct v9fs_fid *temp = NULL;
struct v9fs_fid *return_fid = NULL;
dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
if (fid_list) {
list_for_each_entry_safe(current_fid, temp, fid_list, list) {
if (!current_fid->fidcreate) {
return_fid = current_fid;
break;
}
}
if (!return_fid)
return_fid = current_fid;
}
/* we are at the root but didn't match */
if ((!return_fid) && (dentry->d_parent == dentry)) {
/* TODO: clone attach with new uid */
return_fid = current_fid;
}
if (!return_fid) {
struct dentry *par = current->fs->pwd->d_parent;
int count = 1;
while (par != NULL) {
if (par == dentry)
break;
count++;
if (par == par->d_parent) {
dprintk(DEBUG_ERROR,
"got to root without finding dentry\n");
break;
}
par = par->d_parent;
}
/* XXX - there may be some duplication we can get rid of */
if (par == dentry) {
return_fid = v9fs_fid_walk_up(dentry);
if (IS_ERR(return_fid))
return_fid = NULL;
}
}
return return_fid;
}
struct v9fs_fid *v9fs_fid_get_created(struct dentry *dentry)
{
struct list_head *fid_list;
struct v9fs_fid *fid, *ftmp, *ret;
dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
fid_list = (struct list_head *)dentry->d_fsdata;
ret = NULL;
if (fid_list) {
list_for_each_entry_safe(fid, ftmp, fid_list, list) {
if (fid->fidcreate && fid->pid == current->pid) {
list_del(&fid->list);
ret = fid;
break;
}
}
}
dprintk(DEBUG_9P, "return %p\n", ret);
return ret;
}
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