[apple/xnu.git] / bsd / hfs / hfs_chash.c

/*
 * Copyright (c) 2002-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

/*
 * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *	  must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *	  may be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.	IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)hfs_chash.c
 *	derived from @(#)ufs_ihash.c	8.7 (Berkeley) 5/17/95
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/queue.h>


#include "hfs.h"	/* XXX bringup */
#include "hfs_cnode.h"

extern lck_attr_t *  hfs_lock_attr;
extern lck_grp_t *  hfs_mutex_group;
extern lck_grp_t *  hfs_rwlock_group;

lck_grp_t * chash_lck_grp;
lck_grp_attr_t * chash_lck_grp_attr;
lck_attr_t * chash_lck_attr;

/*
 * Structures associated with cnode caching.
 */
LIST_HEAD(cnodehashhead, cnode) *cnodehashtbl;
u_long	cnodehash;		/* size of hash table - 1 */
#define CNODEHASH(device, inum) (&cnodehashtbl[((device) + (inum)) & cnodehash])

lck_mtx_t  hfs_chash_mutex;


/*
 * Initialize cnode hash table.
 */
__private_extern__
void
hfs_chashinit()
{
	cnodehashtbl = hashinit(desiredvnodes, M_HFSMNT, &cnodehash);

	chash_lck_grp_attr= lck_grp_attr_alloc_init();
	chash_lck_grp  = lck_grp_alloc_init("cnode_hash", chash_lck_grp_attr);
	chash_lck_attr = lck_attr_alloc_init();

	lck_mtx_init(&hfs_chash_mutex, chash_lck_grp, chash_lck_attr);
}


/*
 * Use the device, inum pair to find the incore cnode.
 *
 * If it is in core, but locked, wait for it.
 */
__private_extern__
struct vnode *
hfs_chash_getvnode(dev_t dev, ino_t inum, int wantrsrc, int skiplock)
{
	struct cnode *cp;
	struct vnode *vp;
	int error;
	uint32_t vid;

	/* 
	 * Go through the hash list
	 * If a cnode is in the process of being cleaned out or being
	 * allocated, wait for it to be finished and then try again.
	 */
loop:
	lck_mtx_lock(&hfs_chash_mutex);
	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
		if ((cp->c_fileid != inum) || (cp->c_dev != dev))
			continue;
		/* Wait if cnode is being created or reclaimed. */
		if (ISSET(cp->c_hflag, H_ALLOC | H_TRANSIT | H_ATTACH)) {
		        SET(cp->c_hflag, H_WAITING);

			(void) msleep(cp, &hfs_chash_mutex, PDROP | PINOD,
			              "hfs_chash_getvnode", 0);
			goto loop;
		}
		/*
		 * Skip cnodes that are not in the name space anymore
		 * note that this check is done outside of the proper
		 * lock to catch nodes already in this state... this
		 * state must be rechecked after we acquire the cnode lock
		 */
		if (cp->c_flag & (C_NOEXISTS | C_DELETED)) {
			continue;
		}
		/* Obtain the desired vnode. */
		vp = wantrsrc ? cp->c_rsrc_vp : cp->c_vp;
		if (vp == NULLVP)
			goto exit;

		vid = vnode_vid(vp);
		lck_mtx_unlock(&hfs_chash_mutex);

		if ((error = vnode_getwithvid(vp, vid))) {
		        /*
			 * If vnode is being reclaimed, or has
			 * already changed identity, no need to wait
			 */
		        return (NULL);
		}
		if (!skiplock && hfs_lock(cp, HFS_EXCLUSIVE_LOCK) != 0) {
			vnode_put(vp);
			return (NULL);
		}

		/*
		 * Skip cnodes that are not in the name space anymore
		 * we need to check again with the cnode lock held
		 * because we may have blocked acquiring the vnode ref
		 * or the lock on the cnode which would allow the node
		 * to be unlinked
		 */
		if (cp->c_flag & (C_NOEXISTS | C_DELETED)) {
			if (!skiplock)
		        	hfs_unlock(cp);
			vnode_put(vp);

			return (NULL);
		}			
		return (vp);
	}
exit:
	lck_mtx_unlock(&hfs_chash_mutex);
	return (NULL);
}


/*
 * Use the device, fileid pair to find the incore cnode.
 * If no cnode if found one is created
 *
 * If it is in core, but locked, wait for it.
 */
__private_extern__
int
hfs_chash_snoop(dev_t dev, ino_t inum, int (*callout)(const struct cat_desc *,
                const struct cat_attr *, void *), void * arg)
{
	struct cnode *cp;
	int result = ENOENT;

	/* 
	 * Go through the hash list
	 * If a cnode is in the process of being cleaned out or being
	 * allocated, wait for it to be finished and then try again.
	 */
	lck_mtx_lock(&hfs_chash_mutex);
	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
		if ((cp->c_fileid != inum) || (cp->c_dev != dev))
			continue;
		/* Skip cnodes being created or reclaimed. */
		if (!ISSET(cp->c_hflag, H_ALLOC | H_TRANSIT | H_ATTACH)) {
			result = callout(&cp->c_desc, &cp->c_attr, arg);
		}
		break;
	}
	lck_mtx_unlock(&hfs_chash_mutex);
	return (result);
}


/*
 * Use the device, fileid pair to find the incore cnode.
 * If no cnode if found one is created
 *
 * If it is in core, but locked, wait for it.
 */
__private_extern__
struct cnode *
hfs_chash_getcnode(dev_t dev, ino_t inum, struct vnode **vpp, int wantrsrc, int skiplock)
{
	struct cnode	*cp;
	struct cnode	*ncp = NULL;
	vnode_t		vp;
	uint32_t	vid;

	/* 
	 * Go through the hash list
	 * If a cnode is in the process of being cleaned out or being
	 * allocated, wait for it to be finished and then try again.
	 */
loop:
	lck_mtx_lock(&hfs_chash_mutex);

loop_with_lock:
	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
		if ((cp->c_fileid != inum) || (cp->c_dev != dev))
			continue;
		/*
		 * Wait if cnode is being created, attached to or reclaimed.
		 */
		if (ISSET(cp->c_hflag, H_ALLOC | H_ATTACH | H_TRANSIT)) {
		        SET(cp->c_hflag, H_WAITING);

			(void) msleep(cp, &hfs_chash_mutex, PINOD,
			              "hfs_chash_getcnode", 0);
			goto loop_with_lock;
		}
		/*
		 * Skip cnodes that are not in the name space anymore
		 * note that this check is done outside of the proper
		 * lock to catch nodes already in this state... this
		 * state must be rechecked after we acquire the cnode lock
		 */
		if (cp->c_flag & (C_NOEXISTS | C_DELETED)) {
			continue;
		}
		vp = wantrsrc ? cp->c_rsrc_vp : cp->c_vp;
		if (vp == NULL) {
			/*
			 * The desired vnode isn't there so tag the cnode.
			 */
			SET(cp->c_hflag, H_ATTACH);

			lck_mtx_unlock(&hfs_chash_mutex);
		} else {
			vid = vnode_vid(vp);

			lck_mtx_unlock(&hfs_chash_mutex);

			if (vnode_getwithvid(vp, vid))
		        	goto loop;
		}
		if (ncp) {
		        /*
			 * someone else won the race to create
			 * this cnode and add it to the hash
			 * just dump our allocation
			 */
		        FREE_ZONE(ncp, sizeof(struct cnode), M_HFSNODE);
			ncp = NULL;
		}
		if (!skiplock && hfs_lock(cp, HFS_EXCLUSIVE_LOCK) != 0) {
			if (vp != NULLVP)
				vnode_put(vp);
			lck_mtx_lock(&hfs_chash_mutex);

			if (vp == NULLVP)
			        CLR(cp->c_hflag, H_ATTACH);
			goto loop_with_lock;
		}
		/*
		 * Skip cnodes that are not in the name space anymore
		 * we need to check again with the cnode lock held
		 * because we may have blocked acquiring the vnode ref
		 * or the lock on the cnode which would allow the node
		 * to be unlinked
		 */
		if (cp->c_flag & (C_NOEXISTS | C_DELETED)) {
			if (!skiplock)
				hfs_unlock(cp);
			if (vp != NULLVP)
				vnode_put(vp);
			lck_mtx_lock(&hfs_chash_mutex);

			if (vp == NULLVP)
			        CLR(cp->c_hflag, H_ATTACH);
			goto loop_with_lock;
		}
		*vpp = vp;
		return (cp);
	}

	/* 
	 * Allocate a new cnode
	 */
	if (skiplock)
		panic("%s - should never get here when skiplock is set \n", __FUNCTION__);

	if (ncp == NULL) {
		lck_mtx_unlock(&hfs_chash_mutex);

	        MALLOC_ZONE(ncp, struct cnode *, sizeof(struct cnode), M_HFSNODE, M_WAITOK);
		/*
		 * since we dropped the chash lock, 
		 * we need to go back and re-verify
		 * that this node hasn't come into 
		 * existence...
		 */
		goto loop;
	}
	bzero(ncp, sizeof(struct cnode));
	SET(ncp->c_hflag, H_ALLOC);
	ncp->c_fileid = inum;
	ncp->c_dev = dev;
	TAILQ_INIT(&ncp->c_hintlist); /* make the list empty */

	lck_rw_init(&ncp->c_rwlock, hfs_rwlock_group, hfs_lock_attr);
	if (!skiplock)
		(void) hfs_lock(ncp, HFS_EXCLUSIVE_LOCK);

	/* Insert the new cnode with it's H_ALLOC flag set */
	LIST_INSERT_HEAD(CNODEHASH(dev, inum), ncp, c_hash);
	lck_mtx_unlock(&hfs_chash_mutex);

	*vpp = NULL;
	return (ncp);
}


__private_extern__
void
hfs_chashwakeup(struct cnode *cp, int hflags)
{
	lck_mtx_lock(&hfs_chash_mutex);

	CLR(cp->c_hflag, hflags);

	if (ISSET(cp->c_hflag, H_WAITING)) {
	        CLR(cp->c_hflag, H_WAITING);
		wakeup((caddr_t)cp);
	}
	lck_mtx_unlock(&hfs_chash_mutex);
}


/*
 * Re-hash two cnodes in the hash table.
 */
__private_extern__
void
hfs_chash_rehash(struct cnode *cp1, struct cnode *cp2)
{
	lck_mtx_lock(&hfs_chash_mutex);

	LIST_REMOVE(cp1, c_hash);
	LIST_REMOVE(cp2, c_hash);
	LIST_INSERT_HEAD(CNODEHASH(cp1->c_dev, cp1->c_fileid), cp1, c_hash);
	LIST_INSERT_HEAD(CNODEHASH(cp2->c_dev, cp2->c_fileid), cp2, c_hash);

	lck_mtx_unlock(&hfs_chash_mutex);
}


/*
 * Remove a cnode from the hash table.
 */
__private_extern__
int
hfs_chashremove(struct cnode *cp)
{
	lck_mtx_lock(&hfs_chash_mutex);

	/* Check if a vnode is getting attached */
	if (ISSET(cp->c_hflag, H_ATTACH)) {
		lck_mtx_unlock(&hfs_chash_mutex);
		return (EBUSY);
	}
	LIST_REMOVE(cp, c_hash);
	cp->c_hash.le_next = NULL;
	cp->c_hash.le_prev = NULL;
	
	lck_mtx_unlock(&hfs_chash_mutex);
	return (0);
}

/*
 * Remove a cnode from the hash table and wakeup any waiters.
 */
__private_extern__
void
hfs_chash_abort(struct cnode *cp)
{
	lck_mtx_lock(&hfs_chash_mutex);

	LIST_REMOVE(cp, c_hash);
	cp->c_hash.le_next = NULL;
	cp->c_hash.le_prev = NULL;

	CLR(cp->c_hflag, H_ATTACH | H_ALLOC);
	if (ISSET(cp->c_hflag, H_WAITING)) {
	        CLR(cp->c_hflag, H_WAITING);
		wakeup((caddr_t)cp);
	}
	lck_mtx_unlock(&hfs_chash_mutex);
}


/*
 * mark a cnode as in transistion
 */
__private_extern__
void
hfs_chash_mark_in_transit(struct cnode *cp)
{
	lck_mtx_lock(&hfs_chash_mutex);

        SET(cp->c_hflag, H_TRANSIT);

	lck_mtx_unlock(&hfs_chash_mutex);
}
Commit	Line	Data
9bccf70c	1	/*
91447636	2	* Copyright (c) 2002-2005 Apple Computer, Inc. All rights reserved.
9bccf70c A	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
37839358 A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
9bccf70c	11	*
37839358 A	12	* This Original Code and all software distributed under the License are
37839358 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
9bccf70c A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
9bccf70c A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
37839358 A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
9bccf70c A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22
	23	/*
	24	* Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
	25	* The Regents of the University of California. All rights reserved.
	26	*
	27	* Redistribution and use in source and binary forms, with or without
	28	* modification, are permitted provided that the following conditions
	29	* are met:
	30	* 1. Redistributions of source code must retain the above copyright
	31	* notice, this list of conditions and the following disclaimer.
	32	* 2. Redistributions in binary form must reproduce the above copyright
	33	* notice, this list of conditions and the following disclaimer in the
	34	* documentation and/or other materials provided with the distribution.
	35	* 3. All advertising materials mentioning features or use of this software
	36	* must display the following acknowledgement:
	37	* This product includes software developed by the University of
	38	* California, Berkeley and its contributors.
	39	* 4. Neither the name of the University nor the names of its contributors
	40	* may be used to endorse or promote products derived from this software
	41	* without specific prior written permission.
	42	*
	43	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	44	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	45	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	46	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	47	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	48	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	49	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	50	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	51	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	52	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	53	* SUCH DAMAGE.
	54	*
	55	* @(#)hfs_chash.c
	56	* derived from @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
	57	*/
	58
	59	#include <sys/param.h>
	60	#include <sys/systm.h>
	61	#include <sys/vnode.h>
91447636	62	#include <sys/kernel.h>
9bccf70c A	63	#include <sys/malloc.h>
	64	#include <sys/proc.h>
	65	#include <sys/queue.h>
	66
91447636 A	67
91447636 A	68	#include "hfs.h" /* XXX bringup */
9bccf70c A	69	#include "hfs_cnode.h"
9bccf70c A	70
91447636 A	71	extern lck_attr_t * hfs_lock_attr;
	72	extern lck_grp_t * hfs_mutex_group;
	73	extern lck_grp_t * hfs_rwlock_group;
	74
	75	lck_grp_t * chash_lck_grp;
	76	lck_grp_attr_t * chash_lck_grp_attr;
	77	lck_attr_t * chash_lck_attr;
9bccf70c A	78
	79	/*
	80	* Structures associated with cnode caching.
	81	*/
	82	LIST_HEAD(cnodehashhead, cnode) *cnodehashtbl;
	83	u_long cnodehash; /* size of hash table - 1 */
	84	#define CNODEHASH(device, inum) (&cnodehashtbl[((device) + (inum)) & cnodehash])
91447636 A	85
	86	lck_mtx_t hfs_chash_mutex;
	87
9bccf70c A	88
	89	/*
	90	* Initialize cnode hash table.
	91	*/
	92	__private_extern__
	93	void
	94	hfs_chashinit()
	95	{
	96	cnodehashtbl = hashinit(desiredvnodes, M_HFSMNT, &cnodehash);
91447636 A	97
91447636 A	98	chash_lck_grp_attr= lck_grp_attr_alloc_init();
91447636	99	chash_lck_grp = lck_grp_alloc_init("cnode_hash", chash_lck_grp_attr);
91447636	100	chash_lck_attr = lck_attr_alloc_init();
91447636 A	101
91447636 A	102	lck_mtx_init(&hfs_chash_mutex, chash_lck_grp, chash_lck_attr);
9bccf70c A	103	}
	104
	105
	106	/*
	107	* Use the device, inum pair to find the incore cnode.
	108	*
	109	* If it is in core, but locked, wait for it.
9bccf70c A	110	*/
9bccf70c A	111	__private_extern__
91447636 A	112	struct vnode *
91447636 A	113	hfs_chash_getvnode(dev_t dev, ino_t inum, int wantrsrc, int skiplock)
9bccf70c	114	{
9bccf70c A	115	struct cnode *cp;
	116	struct vnode *vp;
	117	int error;
91447636	118	uint32_t vid;
9bccf70c	119
9bccf70c A	120	/*
	121	* Go through the hash list
	122	* If a cnode is in the process of being cleaned out or being
	123	* allocated, wait for it to be finished and then try again.
	124	*/
	125	loop:
91447636	126	lck_mtx_lock(&hfs_chash_mutex);
9bccf70c A	127	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
	128	if ((cp->c_fileid != inum) \|\| (cp->c_dev != dev))
	129	continue;
91447636 A	130	/* Wait if cnode is being created or reclaimed. */
	131	if (ISSET(cp->c_hflag, H_ALLOC \| H_TRANSIT \| H_ATTACH)) {
	132	SET(cp->c_hflag, H_WAITING);
	133
	134	(void) msleep(cp, &hfs_chash_mutex, PDROP \| PINOD,
	135	"hfs_chash_getvnode", 0);
9bccf70c	136	goto loop;
91447636 A	137	}
	138	/*
	139	* Skip cnodes that are not in the name space anymore
	140	* note that this check is done outside of the proper
	141	* lock to catch nodes already in this state... this
	142	* state must be rechecked after we acquire the cnode lock
	143	*/
	144	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	145	continue;
	146	}
	147	/* Obtain the desired vnode. */
	148	vp = wantrsrc ? cp->c_rsrc_vp : cp->c_vp;
	149	if (vp == NULLVP)
	150	goto exit;
	151
	152	vid = vnode_vid(vp);
	153	lck_mtx_unlock(&hfs_chash_mutex);
	154
	155	if ((error = vnode_getwithvid(vp, vid))) {
	156	/*
	157	* If vnode is being reclaimed, or has
	158	* already changed identity, no need to wait
9bccf70c	159	*/
91447636	160	return (NULL);
9bccf70c	161	}
91447636 A	162	if (!skiplock && hfs_lock(cp, HFS_EXCLUSIVE_LOCK) != 0) {
	163	vnode_put(vp);
	164	return (NULL);
	165	}
	166
	167	/*
	168	* Skip cnodes that are not in the name space anymore
	169	* we need to check again with the cnode lock held
	170	* because we may have blocked acquiring the vnode ref
	171	* or the lock on the cnode which would allow the node
	172	* to be unlinked
	173	*/
	174	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	175	if (!skiplock)
	176	hfs_unlock(cp);
	177	vnode_put(vp);
	178
	179	return (NULL);
	180	}
	181	return (vp);
	182	}
	183	exit:
	184	lck_mtx_unlock(&hfs_chash_mutex);
	185	return (NULL);
	186	}
	187
	188
	189	/*
	190	* Use the device, fileid pair to find the incore cnode.
	191	* If no cnode if found one is created
	192	*
	193	* If it is in core, but locked, wait for it.
	194	*/
	195	__private_extern__
	196	int
	197	hfs_chash_snoop(dev_t dev, ino_t inum, int (callout)(const struct cat_desc ,
	198	const struct cat_attr , void ), void * arg)
	199	{
	200	struct cnode *cp;
	201	int result = ENOENT;
	202
	203	/*
	204	* Go through the hash list
	205	* If a cnode is in the process of being cleaned out or being
	206	* allocated, wait for it to be finished and then try again.
	207	*/
	208	lck_mtx_lock(&hfs_chash_mutex);
	209	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
	210	if ((cp->c_fileid != inum) \|\| (cp->c_dev != dev))
9bccf70c	211	continue;
91447636 A	212	/* Skip cnodes being created or reclaimed. */
	213	if (!ISSET(cp->c_hflag, H_ALLOC \| H_TRANSIT \| H_ATTACH)) {
	214	result = callout(&cp->c_desc, &cp->c_attr, arg);
	215	}
	216	break;
	217	}
	218	lck_mtx_unlock(&hfs_chash_mutex);
	219	return (result);
	220	}
	221
9bccf70c	222
91447636 A	223	/*
	224	* Use the device, fileid pair to find the incore cnode.
	225	* If no cnode if found one is created
	226	*
	227	* If it is in core, but locked, wait for it.
	228	*/
	229	__private_extern__
	230	struct cnode *
	231	hfs_chash_getcnode(dev_t dev, ino_t inum, struct vnode **vpp, int wantrsrc, int skiplock)
	232	{
	233	struct cnode *cp;
	234	struct cnode *ncp = NULL;
	235	vnode_t vp;
	236	uint32_t vid;
	237
	238	/*
	239	* Go through the hash list
	240	* If a cnode is in the process of being cleaned out or being
	241	* allocated, wait for it to be finished and then try again.
	242	*/
	243	loop:
	244	lck_mtx_lock(&hfs_chash_mutex);
	245
	246	loop_with_lock:
	247	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
	248	if ((cp->c_fileid != inum) \|\| (cp->c_dev != dev))
	249	continue;
9bccf70c	250	/*
91447636	251	* Wait if cnode is being created, attached to or reclaimed.
9bccf70c	252	*/
91447636 A	253	if (ISSET(cp->c_hflag, H_ALLOC \| H_ATTACH \| H_TRANSIT)) {
91447636 A	254	SET(cp->c_hflag, H_WAITING);
9bccf70c	255
91447636 A	256	(void) msleep(cp, &hfs_chash_mutex, PINOD,
	257	"hfs_chash_getcnode", 0);
	258	goto loop_with_lock;
	259	}
	260	/*
	261	* Skip cnodes that are not in the name space anymore
	262	* note that this check is done outside of the proper
	263	* lock to catch nodes already in this state... this
	264	* state must be rechecked after we acquire the cnode lock
	265	*/
	266	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	267	continue;
	268	}
	269	vp = wantrsrc ? cp->c_rsrc_vp : cp->c_vp;
	270	if (vp == NULL) {
9bccf70c	271	/*
91447636	272	* The desired vnode isn't there so tag the cnode.
9bccf70c	273	*/
91447636 A	274	SET(cp->c_hflag, H_ATTACH);
	275
	276	lck_mtx_unlock(&hfs_chash_mutex);
	277	} else {
	278	vid = vnode_vid(vp);
	279
	280	lck_mtx_unlock(&hfs_chash_mutex);
	281
	282	if (vnode_getwithvid(vp, vid))
	283	goto loop;
	284	}
	285	if (ncp) {
	286	/*
	287	* someone else won the race to create
	288	* this cnode and add it to the hash
	289	* just dump our allocation
	290	*/
	291	FREE_ZONE(ncp, sizeof(struct cnode), M_HFSNODE);
	292	ncp = NULL;
9bccf70c	293	}
91447636 A	294	if (!skiplock && hfs_lock(cp, HFS_EXCLUSIVE_LOCK) != 0) {
	295	if (vp != NULLVP)
	296	vnode_put(vp);
	297	lck_mtx_lock(&hfs_chash_mutex);
9bccf70c	298
91447636 A	299	if (vp == NULLVP)
	300	CLR(cp->c_hflag, H_ATTACH);
	301	goto loop_with_lock;
	302	}
9bccf70c	303	/*
91447636 A	304	* Skip cnodes that are not in the name space anymore
	305	* we need to check again with the cnode lock held
	306	* because we may have blocked acquiring the vnode ref
	307	* or the lock on the cnode which would allow the node
	308	* to be unlinked
9bccf70c	309	*/
91447636 A	310	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	311	if (!skiplock)
	312	hfs_unlock(cp);
	313	if (vp != NULLVP)
	314	vnode_put(vp);
	315	lck_mtx_lock(&hfs_chash_mutex);
	316
	317	if (vp == NULLVP)
	318	CLR(cp->c_hflag, H_ATTACH);
	319	goto loop_with_lock;
9bccf70c	320	}
91447636	321	*vpp = vp;
9bccf70c A	322	return (cp);
9bccf70c A	323	}
91447636 A	324
	325	/*
	326	* Allocate a new cnode
	327	*/
	328	if (skiplock)
	329	panic("%s - should never get here when skiplock is set \n", __FUNCTION__);
	330
	331	if (ncp == NULL) {
	332	lck_mtx_unlock(&hfs_chash_mutex);
	333
	334	MALLOC_ZONE(ncp, struct cnode *, sizeof(struct cnode), M_HFSNODE, M_WAITOK);
	335	/*
	336	* since we dropped the chash lock,
	337	* we need to go back and re-verify
	338	* that this node hasn't come into
	339	* existence...
	340	*/
	341	goto loop;
	342	}
	343	bzero(ncp, sizeof(struct cnode));
	344	SET(ncp->c_hflag, H_ALLOC);
	345	ncp->c_fileid = inum;
	346	ncp->c_dev = dev;
b36670ce	347	TAILQ_INIT(&ncp->c_hintlist); /* make the list empty */
91447636 A	348
	349	lck_rw_init(&ncp->c_rwlock, hfs_rwlock_group, hfs_lock_attr);
	350	if (!skiplock)
	351	(void) hfs_lock(ncp, HFS_EXCLUSIVE_LOCK);
	352
	353	/* Insert the new cnode with it's H_ALLOC flag set */
	354	LIST_INSERT_HEAD(CNODEHASH(dev, inum), ncp, c_hash);
	355	lck_mtx_unlock(&hfs_chash_mutex);
	356
	357	*vpp = NULL;
	358	return (ncp);
	359	}
	360
	361
	362	__private_extern__
	363	void
	364	hfs_chashwakeup(struct cnode *cp, int hflags)
	365	{
	366	lck_mtx_lock(&hfs_chash_mutex);
	367
	368	CLR(cp->c_hflag, hflags);
	369
	370	if (ISSET(cp->c_hflag, H_WAITING)) {
	371	CLR(cp->c_hflag, H_WAITING);
	372	wakeup((caddr_t)cp);
	373	}
	374	lck_mtx_unlock(&hfs_chash_mutex);
9bccf70c A	375	}
	376
	377
	378	/*
91447636	379	* Re-hash two cnodes in the hash table.
9bccf70c A	380	*/
	381	__private_extern__
	382	void
91447636	383	hfs_chash_rehash(struct cnode cp1, struct cnode cp2)
9bccf70c	384	{
91447636 A	385	lck_mtx_lock(&hfs_chash_mutex);
	386
	387	LIST_REMOVE(cp1, c_hash);
	388	LIST_REMOVE(cp2, c_hash);
	389	LIST_INSERT_HEAD(CNODEHASH(cp1->c_dev, cp1->c_fileid), cp1, c_hash);
	390	LIST_INSERT_HEAD(CNODEHASH(cp2->c_dev, cp2->c_fileid), cp2, c_hash);
	391
	392	lck_mtx_unlock(&hfs_chash_mutex);
9bccf70c A	393	}
	394
	395
	396	/*
	397	* Remove a cnode from the hash table.
	398	*/
	399	__private_extern__
91447636	400	int
9bccf70c A	401	hfs_chashremove(struct cnode *cp)
9bccf70c A	402	{
91447636 A	403	lck_mtx_lock(&hfs_chash_mutex);
	404
	405	/* Check if a vnode is getting attached */
	406	if (ISSET(cp->c_hflag, H_ATTACH)) {
	407	lck_mtx_unlock(&hfs_chash_mutex);
	408	return (EBUSY);
	409	}
	410	LIST_REMOVE(cp, c_hash);
	411	cp->c_hash.le_next = NULL;
	412	cp->c_hash.le_prev = NULL;
	413
	414	lck_mtx_unlock(&hfs_chash_mutex);
	415	return (0);
	416	}
	417
	418	/*
	419	* Remove a cnode from the hash table and wakeup any waiters.
	420	*/
	421	__private_extern__
	422	void
	423	hfs_chash_abort(struct cnode *cp)
	424	{
	425	lck_mtx_lock(&hfs_chash_mutex);
	426
9bccf70c A	427	LIST_REMOVE(cp, c_hash);
	428	cp->c_hash.le_next = NULL;
	429	cp->c_hash.le_prev = NULL;
91447636 A	430
	431	CLR(cp->c_hflag, H_ATTACH \| H_ALLOC);
	432	if (ISSET(cp->c_hflag, H_WAITING)) {
	433	CLR(cp->c_hflag, H_WAITING);
	434	wakeup((caddr_t)cp);
	435	}
	436	lck_mtx_unlock(&hfs_chash_mutex);
9bccf70c A	437	}
9bccf70c A	438
91447636 A	439
	440	/*
	441	* mark a cnode as in transistion
	442	*/
	443	__private_extern__
	444	void
	445	hfs_chash_mark_in_transit(struct cnode *cp)
	446	{
	447	lck_mtx_lock(&hfs_chash_mutex);
	448
	449	SET(cp->c_hflag, H_TRANSIT);
	450
	451	lck_mtx_unlock(&hfs_chash_mutex);
	452	}