path: root/fs/cachefiles/namei.c

/* CacheFiles path walking and related routines
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/quotaops.h>
#include <linux/xattr.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <linux/slab.h>
#include "internal.h"

#define CACHEFILES_KEYBUF_SIZE 512

/*
 * dump debugging info about an object
 */
static noinline
void __cachefiles_printk_object(struct cachefiles_object *object,
				const char *prefix,
				u8 *keybuf)
{
	struct fscache_cookie *cookie;
	unsigned keylen, loop;

	printk(KERN_ERR "%sobject: OBJ%x\n",
	       prefix, object->fscache.debug_id);
	printk(KERN_ERR "%sobjstate=%s fl=%lx swfl=%lx ev=%lx[%lx]\n",
	       prefix, fscache_object_states[object->fscache.state],
	       object->fscache.flags, object->fscache.work.flags,
	       object->fscache.events,
	       object->fscache.event_mask & FSCACHE_OBJECT_EVENTS_MASK);
	printk(KERN_ERR "%sops=%u inp=%u exc=%u\n",
	       prefix, object->fscache.n_ops, object->fscache.n_in_progress,
	       object->fscache.n_exclusive);
	printk(KERN_ERR "%sparent=%p\n",
	       prefix, object->fscache.parent);

	spin_lock(&object->fscache.lock);
	cookie = object->fscache.cookie;
	if (cookie) {
		printk(KERN_ERR "%scookie=%p [pr=%p nd=%p fl=%lx]\n",
		       prefix,
		       object->fscache.cookie,
		       object->fscache.cookie->parent,
		       object->fscache.cookie->netfs_data,
		       object->fscache.cookie->flags);
		if (keybuf)
			keylen = cookie->def->get_key(cookie->netfs_data, keybuf,
						      CACHEFILES_KEYBUF_SIZE);
		else
			keylen = 0;
	} else {
		printk(KERN_ERR "%scookie=NULL\n", prefix);
		keylen = 0;
	}
	spin_unlock(&object->fscache.lock);

	if (keylen) {
		printk(KERN_ERR "%skey=[%u] '", prefix, keylen);
		for (loop = 0; loop < keylen; loop++)
			printk("%02x", keybuf[loop]);
		printk("'\n");
	}
}

/*
 * dump debugging info about a pair of objects
 */
static noinline void cachefiles_printk_object(struct cachefiles_object *object,
					      struct cachefiles_object *xobject)
{
	u8 *keybuf;

	keybuf = kmalloc(CACHEFILES_KEYBUF_SIZE, GFP_NOIO);
	if (object)
		__cachefiles_printk_object(object, "", keybuf);
	if (xobject)
		__cachefiles_printk_object(xobject, "x", keybuf);
	kfree(keybuf);
}

/*
 * mark the owner of a dentry, if there is one, to indicate that that dentry
 * has been preemptively deleted
 * - the caller must hold the i_mutex on the dentry's parent as required to
 *   call vfs_unlink(), vfs_rmdir() or vfs_rename()
 */
static void cachefiles_mark_object_buried(struct cachefiles_cache *cache,
					  struct dentry *dentry)
{
	struct cachefiles_object *object;
	struct rb_node *p;

	_enter(",'%*.*s'",
	       dentry->d_name.len, dentry->d_name.len, dentry->d_name.name);

	write_lock(&cache->active_lock);

	p = cache->active_nodes.rb_node;
	while (p) {
		object = rb_entry(p, struct cachefiles_object, active_node);
		if (object->dentry > dentry)
			p = p->rb_left;
		else if (object->dentry < dentry)
			p = p->rb_right;
		else
			goto found_dentry;
	}

	write_unlock(&cache->active_lock);
	_leave(" [no owner]");
	return;

	/* found the dentry for  */
found_dentry:
	kdebug("preemptive burial: OBJ%x [%s] %p",
	       object->fscache.debug_id,
	       fscache_object_states[object->fscache.state],
	       dentry);

	if (object->fscache.state < FSCACHE_OBJECT_DYING) {
		printk(KERN_ERR "\n");
		printk(KERN_ERR "CacheFiles: Error:"
		       " Can't preemptively bury live object\n");
		cachefiles_printk_object(object, NULL);
	} else if (test_and_set_bit(CACHEFILES_OBJECT_BURIED, &object->flags)) {
		printk(KERN_ERR "CacheFiles: Error:"
		       " Object already preemptively buried\n");
	}

	write_unlock(&cache->active_lock);
	_leave(" [owner marked]");
}

/*
 * record the fact that an object is now active
 */
static int cachefiles_mark_object_active(struct cachefiles_cache *cache,
					 struct cachefiles_object *object)
{
	struct cachefiles_object *xobject;
	struct rb_node **_p, *_parent </