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

/*
 * Copyright (c) 2002-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_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	3	*
8f6c56a5	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
9bccf70c	5	*
8f6c56a5 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
8ad349bb	24	* limitations under the License.
8f6c56a5 A	25	*
8f6c56a5 A	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
9bccf70c A	27	*/
	28
	29	/*
	30	* Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
	31	* The Regents of the University of California. All rights reserved.
	32	*
	33	* Redistribution and use in source and binary forms, with or without
	34	* modification, are permitted provided that the following conditions
	35	* are met:
	36	* 1. Redistributions of source code must retain the above copyright
	37	* notice, this list of conditions and the following disclaimer.
	38	* 2. Redistributions in binary form must reproduce the above copyright
	39	* notice, this list of conditions and the following disclaimer in the
	40	* documentation and/or other materials provided with the distribution.
	41	* 3. All advertising materials mentioning features or use of this software
	42	* must display the following acknowledgement:
	43	* This product includes software developed by the University of
	44	* California, Berkeley and its contributors.
	45	* 4. Neither the name of the University nor the names of its contributors
	46	* may be used to endorse or promote products derived from this software
	47	* without specific prior written permission.
	48	*
	49	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	50	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	51	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	52	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	53	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	54	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	55	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	56	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	57	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	58	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	59	* SUCH DAMAGE.
	60	*
	61	* @(#)hfs_chash.c
	62	* derived from @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
	63	*/
	64
	65	#include <sys/param.h>
	66	#include <sys/systm.h>
	67	#include <sys/vnode.h>
91447636	68	#include <sys/kernel.h>
9bccf70c A	69	#include <sys/malloc.h>
	70	#include <sys/proc.h>
	71	#include <sys/queue.h>
	72
91447636 A	73
91447636 A	74	#include "hfs.h" /* XXX bringup */
9bccf70c A	75	#include "hfs_cnode.h"
9bccf70c A	76
91447636 A	77	extern lck_attr_t * hfs_lock_attr;
	78	extern lck_grp_t * hfs_mutex_group;
	79	extern lck_grp_t * hfs_rwlock_group;
	80
	81	lck_grp_t * chash_lck_grp;
	82	lck_grp_attr_t * chash_lck_grp_attr;
	83	lck_attr_t * chash_lck_attr;
9bccf70c A	84
	85	/*
	86	* Structures associated with cnode caching.
	87	*/
	88	LIST_HEAD(cnodehashhead, cnode) *cnodehashtbl;
	89	u_long cnodehash; /* size of hash table - 1 */
	90	#define CNODEHASH(device, inum) (&cnodehashtbl[((device) + (inum)) & cnodehash])
91447636 A	91
	92	lck_mtx_t hfs_chash_mutex;
	93
9bccf70c A	94
	95	/*
	96	* Initialize cnode hash table.
	97	*/
	98	__private_extern__
	99	void
	100	hfs_chashinit()
	101	{
	102	cnodehashtbl = hashinit(desiredvnodes, M_HFSMNT, &cnodehash);
91447636 A	103
91447636 A	104	chash_lck_grp_attr= lck_grp_attr_alloc_init();
91447636	105	chash_lck_grp = lck_grp_alloc_init("cnode_hash", chash_lck_grp_attr);
91447636	106	chash_lck_attr = lck_attr_alloc_init();
91447636 A	107
91447636 A	108	lck_mtx_init(&hfs_chash_mutex, chash_lck_grp, chash_lck_attr);
9bccf70c A	109	}
	110
	111
	112	/*
	113	* Use the device, inum pair to find the incore cnode.
	114	*
	115	* If it is in core, but locked, wait for it.
9bccf70c A	116	*/
9bccf70c A	117	__private_extern__
91447636 A	118	struct vnode *
91447636 A	119	hfs_chash_getvnode(dev_t dev, ino_t inum, int wantrsrc, int skiplock)
9bccf70c	120	{
9bccf70c A	121	struct cnode *cp;
	122	struct vnode *vp;
	123	int error;
91447636	124	uint32_t vid;
9bccf70c	125
9bccf70c A	126	/*
	127	* Go through the hash list
	128	* If a cnode is in the process of being cleaned out or being
	129	* allocated, wait for it to be finished and then try again.
	130	*/
	131	loop:
91447636	132	lck_mtx_lock(&hfs_chash_mutex);
9bccf70c A	133	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
	134	if ((cp->c_fileid != inum) \|\| (cp->c_dev != dev))
	135	continue;
91447636 A	136	/* Wait if cnode is being created or reclaimed. */
	137	if (ISSET(cp->c_hflag, H_ALLOC \| H_TRANSIT \| H_ATTACH)) {
	138	SET(cp->c_hflag, H_WAITING);
	139
	140	(void) msleep(cp, &hfs_chash_mutex, PDROP \| PINOD,
	141	"hfs_chash_getvnode", 0);
9bccf70c	142	goto loop;
91447636 A	143	}
	144	/*
	145	* Skip cnodes that are not in the name space anymore
	146	* note that this check is done outside of the proper
	147	* lock to catch nodes already in this state... this
	148	* state must be rechecked after we acquire the cnode lock
	149	*/
	150	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	151	continue;
	152	}
	153	/* Obtain the desired vnode. */
	154	vp = wantrsrc ? cp->c_rsrc_vp : cp->c_vp;
	155	if (vp == NULLVP)
	156	goto exit;
	157
	158	vid = vnode_vid(vp);
	159	lck_mtx_unlock(&hfs_chash_mutex);
	160
	161	if ((error = vnode_getwithvid(vp, vid))) {
	162	/*
	163	* If vnode is being reclaimed, or has
	164	* already changed identity, no need to wait
9bccf70c	165	*/
91447636	166	return (NULL);
9bccf70c	167	}
91447636 A	168	if (!skiplock && hfs_lock(cp, HFS_EXCLUSIVE_LOCK) != 0) {
	169	vnode_put(vp);
	170	return (NULL);
	171	}
	172
	173	/*
	174	* Skip cnodes that are not in the name space anymore
	175	* we need to check again with the cnode lock held
	176	* because we may have blocked acquiring the vnode ref
	177	* or the lock on the cnode which would allow the node
	178	* to be unlinked
	179	*/
	180	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	181	if (!skiplock)
	182	hfs_unlock(cp);
	183	vnode_put(vp);
	184
	185	return (NULL);
	186	}
	187	return (vp);
	188	}
	189	exit:
	190	lck_mtx_unlock(&hfs_chash_mutex);
	191	return (NULL);
	192	}
	193
	194
	195	/*
	196	* Use the device, fileid pair to find the incore cnode.
	197	* If no cnode if found one is created
	198	*
	199	* If it is in core, but locked, wait for it.
	200	*/
	201	__private_extern__
	202	int
	203	hfs_chash_snoop(dev_t dev, ino_t inum, int (callout)(const struct cat_desc ,
	204	const struct cat_attr , void ), void * arg)
	205	{
	206	struct cnode *cp;
	207	int result = ENOENT;
	208
	209	/*
	210	* Go through the hash list
	211	* If a cnode is in the process of being cleaned out or being
	212	* allocated, wait for it to be finished and then try again.
	213	*/
	214	lck_mtx_lock(&hfs_chash_mutex);
	215	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
	216	if ((cp->c_fileid != inum) \|\| (cp->c_dev != dev))
9bccf70c	217	continue;
91447636 A	218	/* Skip cnodes being created or reclaimed. */
	219	if (!ISSET(cp->c_hflag, H_ALLOC \| H_TRANSIT \| H_ATTACH)) {
	220	result = callout(&cp->c_desc, &cp->c_attr, arg);
	221	}
	222	break;
	223	}
	224	lck_mtx_unlock(&hfs_chash_mutex);
	225	return (result);
	226	}
	227
9bccf70c	228
91447636 A	229	/*
	230	* Use the device, fileid pair to find the incore cnode.
	231	* If no cnode if found one is created
	232	*
	233	* If it is in core, but locked, wait for it.
	234	*/
	235	__private_extern__
	236	struct cnode *
	237	hfs_chash_getcnode(dev_t dev, ino_t inum, struct vnode **vpp, int wantrsrc, int skiplock)
	238	{
	239	struct cnode *cp;
	240	struct cnode *ncp = NULL;
	241	vnode_t vp;
	242	uint32_t vid;
	243
	244	/*
	245	* Go through the hash list
	246	* If a cnode is in the process of being cleaned out or being
	247	* allocated, wait for it to be finished and then try again.
	248	*/
	249	loop:
	250	lck_mtx_lock(&hfs_chash_mutex);
	251
	252	loop_with_lock:
	253	for (cp = CNODEHASH(dev, inum)->lh_first; cp; cp = cp->c_hash.le_next) {
	254	if ((cp->c_fileid != inum) \|\| (cp->c_dev != dev))
	255	continue;
9bccf70c	256	/*
91447636	257	* Wait if cnode is being created, attached to or reclaimed.
9bccf70c	258	*/
91447636 A	259	if (ISSET(cp->c_hflag, H_ALLOC \| H_ATTACH \| H_TRANSIT)) {
91447636 A	260	SET(cp->c_hflag, H_WAITING);
9bccf70c	261
91447636 A	262	(void) msleep(cp, &hfs_chash_mutex, PINOD,
	263	"hfs_chash_getcnode", 0);
	264	goto loop_with_lock;
	265	}
	266	/*
	267	* Skip cnodes that are not in the name space anymore
	268	* note that this check is done outside of the proper
	269	* lock to catch nodes already in this state... this
	270	* state must be rechecked after we acquire the cnode lock
	271	*/
	272	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	273	continue;
	274	}
	275	vp = wantrsrc ? cp->c_rsrc_vp : cp->c_vp;
	276	if (vp == NULL) {
9bccf70c	277	/*
91447636	278	* The desired vnode isn't there so tag the cnode.
9bccf70c	279	*/
91447636 A	280	SET(cp->c_hflag, H_ATTACH);
	281
	282	lck_mtx_unlock(&hfs_chash_mutex);
	283	} else {
	284	vid = vnode_vid(vp);
	285
	286	lck_mtx_unlock(&hfs_chash_mutex);
	287
	288	if (vnode_getwithvid(vp, vid))
	289	goto loop;
	290	}
	291	if (ncp) {
	292	/*
	293	* someone else won the race to create
	294	* this cnode and add it to the hash
	295	* just dump our allocation
	296	*/
	297	FREE_ZONE(ncp, sizeof(struct cnode), M_HFSNODE);
	298	ncp = NULL;
9bccf70c	299	}
91447636 A	300	if (!skiplock && hfs_lock(cp, HFS_EXCLUSIVE_LOCK) != 0) {
	301	if (vp != NULLVP)
	302	vnode_put(vp);
	303	lck_mtx_lock(&hfs_chash_mutex);
9bccf70c	304
91447636 A	305	if (vp == NULLVP)
	306	CLR(cp->c_hflag, H_ATTACH);
	307	goto loop_with_lock;
	308	}
9bccf70c	309	/*
91447636 A	310	* Skip cnodes that are not in the name space anymore
	311	* we need to check again with the cnode lock held
	312	* because we may have blocked acquiring the vnode ref
	313	* or the lock on the cnode which would allow the node
	314	* to be unlinked
9bccf70c	315	*/
91447636 A	316	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	317	if (!skiplock)
	318	hfs_unlock(cp);
	319	if (vp != NULLVP)
	320	vnode_put(vp);
	321	lck_mtx_lock(&hfs_chash_mutex);
	322
	323	if (vp == NULLVP)
	324	CLR(cp->c_hflag, H_ATTACH);
	325	goto loop_with_lock;
9bccf70c	326	}
91447636	327	*vpp = vp;
9bccf70c A	328	return (cp);
9bccf70c A	329	}
91447636 A	330
	331	/*
	332	* Allocate a new cnode
	333	*/
	334	if (skiplock)
	335	panic("%s - should never get here when skiplock is set \n", __FUNCTION__);
	336
	337	if (ncp == NULL) {
	338	lck_mtx_unlock(&hfs_chash_mutex);
	339
	340	MALLOC_ZONE(ncp, struct cnode *, sizeof(struct cnode), M_HFSNODE, M_WAITOK);
	341	/*
	342	* since we dropped the chash lock,
	343	* we need to go back and re-verify
	344	* that this node hasn't come into
	345	* existence...
	346	*/
	347	goto loop;
	348	}
	349	bzero(ncp, sizeof(struct cnode));
	350	SET(ncp->c_hflag, H_ALLOC);
	351	ncp->c_fileid = inum;
	352	ncp->c_dev = dev;
b36670ce	353	TAILQ_INIT(&ncp->c_hintlist); /* make the list empty */
91447636 A	354
	355	lck_rw_init(&ncp->c_rwlock, hfs_rwlock_group, hfs_lock_attr);
	356	if (!skiplock)
	357	(void) hfs_lock(ncp, HFS_EXCLUSIVE_LOCK);
	358
	359	/* Insert the new cnode with it's H_ALLOC flag set */
	360	LIST_INSERT_HEAD(CNODEHASH(dev, inum), ncp, c_hash);
	361	lck_mtx_unlock(&hfs_chash_mutex);
	362
	363	*vpp = NULL;
	364	return (ncp);
	365	}
	366
	367
	368	__private_extern__
	369	void
	370	hfs_chashwakeup(struct cnode *cp, int hflags)
	371	{
	372	lck_mtx_lock(&hfs_chash_mutex);
	373
	374	CLR(cp->c_hflag, hflags);
	375
	376	if (ISSET(cp->c_hflag, H_WAITING)) {
	377	CLR(cp->c_hflag, H_WAITING);
	378	wakeup((caddr_t)cp);
	379	}
	380	lck_mtx_unlock(&hfs_chash_mutex);
9bccf70c A	381	}
	382
	383
	384	/*
91447636	385	* Re-hash two cnodes in the hash table.
9bccf70c A	386	*/
	387	__private_extern__
	388	void
91447636	389	hfs_chash_rehash(struct cnode cp1, struct cnode cp2)
9bccf70c	390	{
91447636 A	391	lck_mtx_lock(&hfs_chash_mutex);
	392
	393	LIST_REMOVE(cp1, c_hash);
	394	LIST_REMOVE(cp2, c_hash);
	395	LIST_INSERT_HEAD(CNODEHASH(cp1->c_dev, cp1->c_fileid), cp1, c_hash);
	396	LIST_INSERT_HEAD(CNODEHASH(cp2->c_dev, cp2->c_fileid), cp2, c_hash);
	397
	398	lck_mtx_unlock(&hfs_chash_mutex);
9bccf70c A	399	}
	400
	401
	402	/*
	403	* Remove a cnode from the hash table.
	404	*/
	405	__private_extern__
91447636	406	int
9bccf70c A	407	hfs_chashremove(struct cnode *cp)
9bccf70c A	408	{
91447636 A	409	lck_mtx_lock(&hfs_chash_mutex);
	410
	411	/* Check if a vnode is getting attached */
	412	if (ISSET(cp->c_hflag, H_ATTACH)) {
	413	lck_mtx_unlock(&hfs_chash_mutex);
	414	return (EBUSY);
	415	}
	416	LIST_REMOVE(cp, c_hash);
	417	cp->c_hash.le_next = NULL;
	418	cp->c_hash.le_prev = NULL;
	419
	420	lck_mtx_unlock(&hfs_chash_mutex);
	421	return (0);
	422	}
	423
	424	/*
	425	* Remove a cnode from the hash table and wakeup any waiters.
	426	*/
	427	__private_extern__
	428	void
	429	hfs_chash_abort(struct cnode *cp)
	430	{
	431	lck_mtx_lock(&hfs_chash_mutex);
	432
9bccf70c A	433	LIST_REMOVE(cp, c_hash);
	434	cp->c_hash.le_next = NULL;
	435	cp->c_hash.le_prev = NULL;
91447636 A	436
	437	CLR(cp->c_hflag, H_ATTACH \| H_ALLOC);
	438	if (ISSET(cp->c_hflag, H_WAITING)) {
	439	CLR(cp->c_hflag, H_WAITING);
	440	wakeup((caddr_t)cp);
	441	}
	442	lck_mtx_unlock(&hfs_chash_mutex);
9bccf70c A	443	}
9bccf70c A	444
91447636 A	445
	446	/*
	447	* mark a cnode as in transistion
	448	*/
	449	__private_extern__
	450	void
	451	hfs_chash_mark_in_transit(struct cnode *cp)
	452	{
	453	lck_mtx_lock(&hfs_chash_mutex);
	454
	455	SET(cp->c_hflag, H_TRANSIT);
	456
	457	lck_mtx_unlock(&hfs_chash_mutex);
	458	}