[mirror_ubuntu-zesty-kernel.git] / fs / 9p / fid.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/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 "transport.h"
#include "mux.h"
#include "conv.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, NULL);
	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;
}
Commit	Line	Data
3ed8491c EVH	1	/*
	2	* V9FS FID Management
	3	*
	4	* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to:
	18	* Free Software Foundation
	19	* 51 Franklin Street, Fifth Floor
	20	* Boston, MA 02111-1301 USA
	21	*
	22	*/
	23
	24	#include <linux/config.h>
	25	#include <linux/module.h>
	26	#include <linux/errno.h>
	27	#include <linux/fs.h>
	28	#include <linux/idr.h>
	29
	30	#include "debug.h"
	31	#include "v9fs.h"
	32	#include "9p.h"
	33	#include "v9fs_vfs.h"
	34	#include "transport.h"
	35	#include "mux.h"
	36	#include "conv.h"
	37	#include "fid.h"
	38
	39	/**
	40	* v9fs_fid_insert - add a fid to a dentry
	41	* @fid: fid to add
	42	* @dentry: dentry that it is being added to
	43	*
	44	*/
	45
	46	static int v9fs_fid_insert(struct v9fs_fid fid, struct dentry dentry)
	47	{
	48	struct list_head fid_list = (struct list_head )dentry->d_fsdata;
	49	dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
	50	dentry->d_iname, dentry);
	51	if (dentry->d_fsdata == NULL) {
	52	dentry->d_fsdata =
	53	kmalloc(sizeof(struct list_head), GFP_KERNEL);
	54	if (dentry->d_fsdata == NULL) {
	55	dprintk(DEBUG_ERROR, "Out of memory\n");
	56	return -ENOMEM;
	57	}
	58	fid_list = (struct list_head *)dentry->d_fsdata;
	59	INIT_LIST_HEAD(fid_list); /* Initialize list head */
	60	}
	61
	62	fid->uid = current->uid;
	63	fid->pid = current->pid;
	64	list_add(&fid->list, fid_list);
65	return 0;
66	}
67
68	/**
69	* v9fs_fid_create - allocate a FID structure
70	* @dentry - dentry to link newly created fid to
71	*
72	*/
73
0b8dd177 LI	74	struct v9fs_fid v9fs_fid_create(struct dentry dentry,
0b8dd177 LI	75	struct v9fs_session_info *v9ses, int fid, int create)
3ed8491c EVH	76	{
	77	struct v9fs_fid *new;
	78
0b8dd177 LI	79	dprintk(DEBUG_9P, "fid create dentry %p, fid %d, create %d\n",
	80	dentry, fid, create);
	81
3ed8491c EVH	82	new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
	83	if (new == NULL) {
	84	dprintk(DEBUG_ERROR, "Out of Memory\n");
	85	return ERR_PTR(-ENOMEM);
	86	}
	87
0b8dd177 LI	88	new->fid = fid;
0b8dd177 LI	89	new->v9ses = v9ses;
3ed8491c	90	new->fidopen = 0;
0b8dd177	91	new->fidcreate = create;
3ed8491c EVH	92	new->fidclunked = 0;
3ed8491c EVH	93	new->iounit = 0;
0b8dd177 LI	94	new->rdir_pos = 0;
0b8dd177 LI	95	new->rdir_fcall = NULL;
3ed8491c EVH	96
	97	if (v9fs_fid_insert(new, dentry) == 0)
	98	return new;
	99	else {
	100	dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
	101	kfree(new);
	102	return NULL;
	103	}
	104	}
	105
	106	/**
	107	* v9fs_fid_destroy - deallocate a FID structure
	108	* @fid: fid to destroy
	109	*
	110	*/
	111
	112	void v9fs_fid_destroy(struct v9fs_fid *fid)
	113	{
	114	list_del(&fid->list);
	115	kfree(fid);
	116	}
	117
0b8dd177 LI	118	/**
	119	* v9fs_fid_walk_up - walks from the process current directory
	120	* up to the specified dentry.
	121	*/
	122	static struct v9fs_fid v9fs_fid_walk_up(struct dentry dentry)
	123	{
	124	int fidnum, cfidnum, err;
	125	struct v9fs_fid *cfid;
	126	struct dentry *cde;
	127	struct v9fs_session_info *v9ses;
	128
	129	v9ses = v9fs_inode2v9ses(current->fs->pwd->d_inode);
	130	cfid = v9fs_fid_lookup(current->fs->pwd);
	131	if (cfid == NULL) {
	132	dprintk(DEBUG_ERROR, "process cwd doesn't have a fid\n");
	133	return ERR_PTR(-ENOENT);
	134	}
	135
	136	cfidnum = cfid->fid;
	137	cde = current->fs->pwd;
	138	/* TODO: take advantage of multiwalk */
	139
	140	fidnum = v9fs_get_idpool(&v9ses->fidpool);
	141	if (fidnum < 0) {
	142	dprintk(DEBUG_ERROR, "could not get a new fid num\n");
	143	err = -ENOENT;
	144	goto clunk_fid;
	145	}
	146
	147	while (cde != dentry) {
	148	if (cde == cde->d_parent) {
	149	dprintk(DEBUG_ERROR, "can't find dentry\n");
	150	err = -ENOENT;
	151	goto clunk_fid;
	152	}
	153
	154	err = v9fs_t_walk(v9ses, cfidnum, fidnum, "..", NULL);
	155	if (err < 0) {
	156	dprintk(DEBUG_ERROR, "problem walking to parent\n");
	157	goto clunk_fid;
	158	}
	159
	160	cfidnum = fidnum;
	161	cde = cde->d_parent;
	162	}
	163
	164	return v9fs_fid_create(dentry, v9ses, fidnum, 0);
	165
	166	clunk_fid:
	167	v9fs_t_clunk(v9ses, fidnum, NULL);
	168	return ERR_PTR(err);
	169	}
	170
3ed8491c EVH	171	/**
	172	* v9fs_fid_lookup - retrieve the right fid from a particular dentry
	173	* @dentry: dentry to look for fid in
	174	* @type: intent of lookup (operation or traversal)
	175	*
	176	* search list of fids associated with a dentry for a fid with a matching
	177	* thread id or uid. If that fails, look up the dentry's parents to see if you
	178	* can find a matching fid.
	179	*
	180	*/
	181
0b8dd177	182	struct v9fs_fid v9fs_fid_lookup(struct dentry dentry)
3ed8491c EVH	183	{
	184	struct list_head fid_list = (struct list_head )dentry->d_fsdata;
	185	struct v9fs_fid *current_fid = NULL;
	186	struct v9fs_fid *temp = NULL;
	187	struct v9fs_fid *return_fid = NULL;
3ed8491c	188
0b8dd177	189	dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
3ed8491c	190
0b8dd177	191	if (fid_list) {
3ed8491c	192	list_for_each_entry_safe(current_fid, temp, fid_list, list) {
0b8dd177 LI	193	if (!current_fid->fidcreate) {
	194	return_fid = current_fid;
	195	break;
3ed8491c EVH	196	}
3ed8491c EVH	197	}
0b8dd177 LI	198
	199	if (!return_fid)
	200	return_fid = current_fid;
3ed8491c EVH	201	}
	202
	203	/* we are at the root but didn't match */
	204	if ((!return_fid) && (dentry->d_parent == dentry)) {
	205	/* TODO: clone attach with new uid */
	206	return_fid = current_fid;
	207	}
	208
	209	if (!return_fid) {
	210	struct dentry *par = current->fs->pwd->d_parent;
	211	int count = 1;
	212	while (par != NULL) {
	213	if (par == dentry)
	214	break;
	215	count++;
	216	if (par == par->d_parent) {
	217	dprintk(DEBUG_ERROR,
	218	"got to root without finding dentry\n");
	219	break;
	220	}
	221	par = par->d_parent;
	222	}
	223
	224	/* XXX - there may be some duplication we can get rid of */
	225	if (par == dentry) {
0b8dd177 LI	226	return_fid = v9fs_fid_walk_up(dentry);
	227	if (IS_ERR(return_fid))
	228	return_fid = NULL;
	229	}
	230	}
3ed8491c	231
0b8dd177 LI	232	return return_fid;
0b8dd177 LI	233	}
3ed8491c	234
0b8dd177 LI	235	struct v9fs_fid v9fs_fid_get_created(struct dentry dentry)
	236	{
	237	struct list_head *fid_list;
	238	struct v9fs_fid fid, ftmp, *ret;
	239
	240	dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
	241	fid_list = (struct list_head *)dentry->d_fsdata;
	242	ret = NULL;
	243	if (fid_list) {
	244	list_for_each_entry_safe(fid, ftmp, fid_list, list) {
	245	if (fid->fidcreate && fid->pid == current->pid) {
	246	list_del(&fid->list);
	247	ret = fid;
	248	break;
3ed8491c EVH	249	}
	250	}
	251	}
	252
0b8dd177 LI	253	dprintk(DEBUG_9P, "return %p\n", ret);
0b8dd177 LI	254	return ret;
3ed8491c	255	}