[net-next-2.6.git] / fs / 9p / vfs_dentry.c

/*
 *  linux/fs/9p/vfs_dentry.c
 *
 * This file contians vfs dentry ops for the 9P2000 protocol.
 *
 *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  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/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/inet.h>
#include <linux/namei.h>
#include <linux/idr.h>

#include "debug.h"
#include "v9fs.h"
#include "9p.h"
#include "v9fs_vfs.h"
#include "conv.h"
#include "fid.h"

/**
 * v9fs_dentry_validate - VFS dcache hook to validate cache
 * @dentry:  dentry that is being validated
 * @nd: path data
 *
 * dcache really shouldn't be used for 9P2000 as at all due to
 * potential attached semantics to directory traversal (walk).
 *
 * FUTURE: look into how to use dcache to allow multi-stage
 * walks in Plan 9 & potential for better dcache operation which
 * would remain valid for Plan 9 semantics.  Older versions
 * had validation via stat for those interested.  However, since
 * stat has the same approximate overhead as walk there really
 * is no difference.  The only improvement would be from a
 * time-decay cache like NFS has and that undermines the
 * synchronous nature of 9P2000.
 *
 */

static int v9fs_dentry_validate(struct dentry *dentry, struct nameidata *nd)
{
	struct dentry *dc = current->fs->pwd;

	dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
	if (v9fs_fid_lookup(dentry)) {
		dprintk(DEBUG_VFS, "VALID\n");
		return 1;
	}

	while (dc != NULL) {
		if (dc == dentry) {
			dprintk(DEBUG_VFS, "VALID\n");
			return 1;
		}
		if (dc == dc->d_parent)
			break;

		dc = dc->d_parent;
	}

	dprintk(DEBUG_VFS, "INVALID\n");
	return 0;
}

/**
 * v9fs_dentry_release - called when dentry is going to be freed
 * @dentry:  dentry that is being release
 *
 */

void v9fs_dentry_release(struct dentry *dentry)
{
	int err;

	dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);

	if (dentry->d_fsdata != NULL) {
		struct list_head *fid_list = dentry->d_fsdata;
		struct v9fs_fid *temp = NULL;
		struct v9fs_fid *current_fid = NULL;

		list_for_each_entry_safe(current_fid, temp, fid_list, list) {
			err = v9fs_t_clunk(current_fid->v9ses, current_fid->fid);

			if (err < 0)
				dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);

			v9fs_fid_destroy(current_fid);
		}

		kfree(dentry->d_fsdata);	/* free the list_head */
	}
}

struct dentry_operations v9fs_dentry_operations = {
	.d_revalidate = v9fs_dentry_validate,
	.d_release = v9fs_dentry_release,
};
Commit	Line	Data
e69e7fe5 EVH	1	/*
	2	* linux/fs/9p/vfs_dentry.c
	3	*
	4	* This file contians vfs dentry ops for the 9P2000 protocol.
	5	*
	6	* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
	7	* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License, or
	12	* (at your option) any later version.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program; if not, write to:
	21	* Free Software Foundation
	22	* 51 Franklin Street, Fifth Floor
	23	* Boston, MA 02111-1301 USA
	24	*
	25	*/
	26
	27	#include <linux/module.h>
	28	#include <linux/errno.h>
	29	#include <linux/fs.h>
	30	#include <linux/file.h>
	31	#include <linux/pagemap.h>
	32	#include <linux/stat.h>
	33	#include <linux/string.h>
	34	#include <linux/smp_lock.h>
	35	#include <linux/inet.h>
	36	#include <linux/namei.h>
	37	#include <linux/idr.h>
	38
	39	#include "debug.h"
	40	#include "v9fs.h"
	41	#include "9p.h"
	42	#include "v9fs_vfs.h"
	43	#include "conv.h"
	44	#include "fid.h"
	45
	46	/**
	47	* v9fs_dentry_validate - VFS dcache hook to validate cache
	48	* @dentry: dentry that is being validated
	49	* @nd: path data
	50	*
	51	* dcache really shouldn't be used for 9P2000 as at all due to
	52	* potential attached semantics to directory traversal (walk).
	53	*
	54	* FUTURE: look into how to use dcache to allow multi-stage
	55	* walks in Plan 9 & potential for better dcache operation which
	56	* would remain valid for Plan 9 semantics. Older versions
	57	* had validation via stat for those interested. However, since
	58	* stat has the same approximate overhead as walk there really
	59	* is no difference. The only improvement would be from a
	60	* time-decay cache like NFS has and that undermines the
	61	* synchronous nature of 9P2000.
	62	*
	63	*/
	64
65	static int v9fs_dentry_validate(struct dentry dentry, struct nameidata nd)
66	{
67	struct dentry *dc = current->fs->pwd;
68
69	dprintk(DEBUG_VFS, "dentry: %s (%p)\n", dentry->d_iname, dentry);
0b8dd177	70	if (v9fs_fid_lookup(dentry)) {
e69e7fe5 EVH	71	dprintk(DEBUG_VFS, "VALID\n");
	72	return 1;
	73	}
	74
	75	while (dc != NULL) {
	76	if (dc == dentry) {
	77	dprintk(DEBUG_VFS, "VALID\n");
	78	return 1;
	79	}
	80	if (dc == dc->d_parent)
	81	break;
	82
	83	dc = dc->d_parent;
	84	}
	85
	86	dprintk(DEBUG_VFS, "INVALID\n");
	87	return 0;
	88	}
	89
	90	/**
	91	* v9fs_dentry_release - called when dentry is going to be freed
	92	* @dentry: dentry that is being release
	93	*
	94	*/
	95
	96	void v9fs_dentry_release(struct dentry *dentry)
	97	{
3cf6429a LI	98	int err;
3cf6429a LI	99
e69e7fe5 EVH	100	dprintk(DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
	101
	102	if (dentry->d_fsdata != NULL) {
	103	struct list_head *fid_list = dentry->d_fsdata;
	104	struct v9fs_fid *temp = NULL;
	105	struct v9fs_fid *current_fid = NULL;
e69e7fe5 EVH	106
e69e7fe5 EVH	107	list_for_each_entry_safe(current_fid, temp, fid_list, list) {
3cf6429a	108	err = v9fs_t_clunk(current_fid->v9ses, current_fid->fid);
e69e7fe5	109
3cf6429a LI	110	if (err < 0)
3cf6429a LI	111	dprintk(DEBUG_ERROR, "clunk failed: %d\n", err);
e69e7fe5	112
e69e7fe5 EVH	113	v9fs_fid_destroy(current_fid);
	114	}
	115
	116	kfree(dentry->d_fsdata); /* free the list_head */
	117	}
	118	}
	119
	120	struct dentry_operations v9fs_dentry_operations = {
	121	.d_revalidate = v9fs_dentry_validate,
	122	.d_release = v9fs_dentry_release,
	123	};