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

/*
 * Copyright (c) 1999-2004 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@
 */


#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <vfs/vfs_support.h>
#include <libkern/libkern.h>

#include "hfs.h"
#include "hfs_catalog.h"
#include "hfs_format.h"
#include "hfs_endian.h"


static int cur_link_id = 0;


/*
 * Create a new indirect link
 *
 * An indirect link is a reference to a data node.  The only useable
 * fields in the link are the link number, parentID, name and text
 * encoding.  All other catalog fields are ignored.
 */
static int
createindirectlink(struct hfsmount *hfsmp, u_int32_t linknum,
			u_int32_t linkparid, char *linkName, cnid_t *linkcnid)
{
	struct FndrFileInfo *fip;
	struct cat_desc desc;
	struct cat_attr attr;
	int result;

	/* Setup the descriptor */
	bzero(&desc, sizeof(desc));
	desc.cd_nameptr = linkName;
	desc.cd_namelen = strlen(linkName);
	desc.cd_parentcnid = linkparid;

	/* Setup the default attributes */
	bzero(&attr, sizeof(attr));
	
	/* links are matched to data nodes by link ID and to volumes by create date */
	attr.ca_rdev = linknum;  /* note: cat backend overloads ca_rdev to be the linknum when nlink = 0 */
	attr.ca_itime = HFSTOVCB(hfsmp)->vcbCrDate;
	attr.ca_mode = S_IFREG;

	fip = (struct FndrFileInfo *)&attr.ca_finderinfo;
	fip->fdType    = SWAP_BE32 (kHardLinkFileType);	/* 'hlnk' */
	fip->fdCreator = SWAP_BE32 (kHFSPlusCreator);	/* 'hfs+' */
	fip->fdFlags   = SWAP_BE16 (kHasBeenInited);

	/* Create the indirect link directly in the catalog */
	result = cat_create(hfsmp, &desc, &attr, NULL);

	if (result == 0 && linkcnid != NULL)
		*linkcnid = attr.ca_fileid;

	return (result);
}


/*
 * 2 locks are needed (dvp and vp)
 * also need catalog lock
 *
 * caller's responsibility:
 *		componentname cleanup
 *		unlocking dvp and vp
 */
static int
hfs_makelink(struct hfsmount *hfsmp, struct cnode *cp, struct cnode *dcp,
		struct componentname *cnp)
{
	vfs_context_t ctx = cnp->cn_context;
	struct proc *p = vfs_context_proc(ctx);
	u_int32_t indnodeno = 0;
	char inodename[32]; 
	struct cat_desc to_desc;
	int newlink = 0;
	int lockflags;
	int retval;
	cat_cookie_t cookie;
	cnid_t orig_cnid;

	if (cur_link_id == 0) {
	    cur_link_id = ((random() & 0x3fffffff) + 100);
	    // printf("hfs: initializing cur link id to: 0x%.8x\n", cur_link_id);
	}
	
	/* We don't allow link nodes in our Private Meta Data folder! */
	if (dcp->c_fileid == hfsmp->hfs_privdir_desc.cd_cnid)
		return (EPERM);

	if (hfs_freeblks(hfsmp, 0) == 0)
		return (ENOSPC);

	bzero(&cookie, sizeof(cat_cookie_t));
	/* Reserve some space in the Catalog file. */
	if ((retval = cat_preflight(hfsmp, (2 * CAT_CREATE)+ CAT_RENAME, &cookie, p))) {
		return (retval);
	}

	lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);

	// save off a copy of the current cnid so we can put 
	// it back if we get errors down below
	orig_cnid = cp->c_desc.cd_cnid;

	/*
	 * If this is a new hardlink then we need to create the data
	 * node (inode) and replace the original file with a link node.
	 */
	if (cp->c_nlink == 2 && (cp->c_flag & C_HARDLINK) == 0) {
		newlink = 1;
		bzero(&to_desc, sizeof(to_desc));
		to_desc.cd_parentcnid = hfsmp->hfs_privdir_desc.cd_cnid;
		to_desc.cd_cnid = cp->c_fileid;

		do {
			/* get a unique indirect node number */
			if (retval == 0) {
			    indnodeno = cp->c_fileid;
			} else {
			    indnodeno = cur_link_id++;
			}

			MAKE_INODE_NAME(inodename, indnodeno);

			/* move source file to data node directory */
			to_desc.cd_nameptr = inodename;
			to_desc.cd_namelen = strlen(inodename);
		
			retval = cat_rename(hfsmp, &cp->c_desc, &hfsmp->hfs_privdir_desc,
					&to_desc, NULL);

			if (retval != 0 && retval != EEXIST) {
			    printf("hfs_makelink: cat_rename to %s failed (%d). fileid %d\n",
				inodename, retval, cp->c_fileid);
			}

		} while (retval == EEXIST);
		if (retval)
			goto out;

		/* Replace source file with link node */
		retval = createindirectlink(hfsmp, indnodeno, cp->c_parentcnid,
				cp->c_desc.cd_nameptr, &cp->c_desc.cd_cnid);
		if (retval) {
		    /* put it source file back */
		    int err;

		    // Put this back to what it was before.
		    cp->c_desc.cd_cnid = orig_cnid;

		    err = cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
		    if (err)
			panic("hfs_makelink: error %d from cat_rename backout 1", err);
		    goto out;
		}
		cp->c_rdev = indnodeno;
	} else {
		indnodeno = cp->c_rdev;
	}

	/*
	 * Create a catalog entry for the new link (parentID + name).
	 */
	retval = createindirectlink(hfsmp, indnodeno, dcp->c_fileid, cnp->cn_nameptr, NULL);
	if (retval && newlink) {
	    int err;

	    /* Get rid of new link */
	    (void) cat_delete(hfsmp, &cp->c_desc, &cp->c_attr);
	    
	    // Put this back to what it was before.
	    cp->c_desc.cd_cnid = orig_cnid;

	    /* Put the source file back */
	    err = cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
	    if (err)
		panic("hfs_makelink: error %d from cat_rename backout 2", err);

	    goto out;
	}

	/*
	 * Finally, if this is a new hardlink then:
	 *  - update HFS Private Data dir
	 *  - mark the cnode as a hard link
	 */
	if (newlink) {
		vnode_t vp;
		
	    if (retval != 0) {
		panic("hfs_makelink: retval %d but newlink = 1!\n", retval);
	    }
	    
		hfsmp->hfs_privdir_attr.ca_entries++;
		retval = cat_update(hfsmp, &hfsmp->hfs_privdir_desc,
				    &hfsmp->hfs_privdir_attr, NULL, NULL);
		if (retval != 0) {
		    panic("hfs_makelink: cat_update of privdir failed! (%d)\n",
			  retval);
		}
		hfs_volupdate(hfsmp, VOL_MKFILE, 0);
		cp->c_flag |= C_HARDLINK;
		if ((vp = cp->c_vp) != NULLVP) {
			if (vnode_get(vp) == 0) {
				vnode_set_hard_link(vp);
				vnode_put(vp);
			}
		}
		if ((vp = cp->c_rsrc_vp) != NULLVP) {
			if (vnode_get(vp) == 0) {
				vnode_set_hard_link(vp);
				vnode_put(vp);
			}
		}
		cp->c_touch_chgtime = TRUE;
		cp->c_flag |= C_FORCEUPDATE;
	}
	dcp->c_flag |= C_FORCEUPDATE;

out:
	hfs_systemfile_unlock(hfsmp, lockflags);

	cat_postflight(hfsmp, &cookie, p);
	return (retval);
}


/*
 * link vnode call
#% link		vp	U U U
#% link		tdvp	L U U
#
 vnop_link {
     IN WILLRELE struct vnode *vp;
     IN struct vnode *targetPar_vp;
     IN struct componentname *cnp;
     IN vfs_context_t context;

     */
__private_extern__
int
hfs_vnop_link(struct vnop_link_args *ap)
{
	struct hfsmount *hfsmp;
	struct vnode *vp = ap->a_vp;
	struct vnode *tdvp = ap->a_tdvp;
	struct componentname *cnp = ap->a_cnp;
	struct cnode *cp;
	struct cnode *tdcp;
	enum vtype v_type;
	int error, ret, lockflags;
	struct cat_desc cndesc;

	if (VTOVCB(tdvp)->vcbSigWord != kHFSPlusSigWord) {
		return err_link(ap);	/* hfs disks don't support hard links */
	}
	if (VTOHFS(vp)->hfs_privdir_desc.cd_cnid == 0) {
		return err_link(ap);	/* no private metadata dir, no links possible */
	}
	if (vnode_mount(tdvp) != vnode_mount(vp)) {
		return (EXDEV);
	}
	if ((error = hfs_lockpair(VTOC(tdvp), VTOC(vp), HFS_EXCLUSIVE_LOCK))) {
		return (error);
	}
	tdcp = VTOC(tdvp);
	cp = VTOC(vp);
	hfsmp = VTOHFS(vp);

	if (cp->c_nlink >= HFS_LINK_MAX) {
		error = EMLINK;
		goto out;
	}
	if (cp->c_flags & (IMMUTABLE | APPEND)) {
		error = EPERM;
		goto out;
	}
	if (cp->c_flag & (C_NOEXISTS | C_DELETED)) {
	    error = ENOENT;
	    goto out;
	}
	
	v_type = vnode_vtype(vp);
	if (v_type == VBLK || v_type == VCHR) {
		error = EINVAL;  /* cannot link to a special file */
		goto out;
	}

	if (hfs_start_transaction(hfsmp) != 0) {
	    error = EINVAL;  /* cannot link to a special file */
	    goto out;
	}

	cp->c_nlink++;
	cp->c_touch_chgtime = TRUE;

	error = hfs_makelink(hfsmp, cp, tdcp, cnp);
	if (error) {
		cp->c_nlink--;
		hfs_volupdate(hfsmp, VOL_UPDATE, 0);
	} else {
		/* Invalidate negative cache entries in the destination directory */
		if (hfsmp->hfs_flags & HFS_CASE_SENSITIVE)
			cache_purge_negatives(tdvp);

		/* Update the target directory and volume stats */
		tdcp->c_nlink++;
		tdcp->c_entries++;
		tdcp->c_touch_chgtime = TRUE;
		tdcp->c_touch_modtime = TRUE;
		tdcp->c_flag |= C_FORCEUPDATE;

		error = hfs_update(tdvp, 0);
		if (error) {
		    panic("hfs_vnop_link: error updating tdvp 0x%x\n", tdvp);
		}

		hfs_volupdate(hfsmp, VOL_MKFILE,
			(tdcp->c_cnid == kHFSRootFolderID));
	}

	cp->c_flag |= C_FORCEUPDATE;    // otherwise hfs_update() might skip the update

	if ((ret = hfs_update(vp, TRUE)) != 0) {
	    panic("hfs_vnop_link: error %d updating vp @ 0x%x\n", ret, vp);
	}

	hfs_end_transaction(hfsmp);
	
	HFS_KNOTE(vp, NOTE_LINK);
	HFS_KNOTE(tdvp, NOTE_WRITE);
out:
	hfs_unlockpair(tdcp, cp);
	return (error);
}
Commit	Line	Data
1c79356b	1	/*
91447636	2	* Copyright (c) 1999-2004 Apple Computer, Inc. All rights reserved.
1c79356b	3	*
6601e61a	4	* @APPLE_LICENSE_HEADER_START@
1c79356b	5	*
6601e61a 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.
8f6c56a5	11	*
6601e61a A	12	* This Original Code and all software distributed under the License are
6601e61a A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
8f6c56a5 A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
6601e61a 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.
8f6c56a5	19	*
6601e61a	20	* @APPLE_LICENSE_HEADER_END@
1c79356b A	21	*/
1c79356b A	22
1c79356b A	23
	24	#include <sys/systm.h>
	25	#include <sys/kernel.h>
	26	#include <sys/malloc.h>
9bccf70c	27	#include <sys/mount.h>
1c79356b A	28	#include <sys/stat.h>
	29	#include <sys/vnode.h>
	30	#include <vfs/vfs_support.h>
	31	#include <libkern/libkern.h>
	32
	33	#include "hfs.h"
9bccf70c A	34	#include "hfs_catalog.h"
	35	#include "hfs_format.h"
	36	#include "hfs_endian.h"
1c79356b A	37
1c79356b A	38
91447636 A	39	static int cur_link_id = 0;
	40
	41
1c79356b A	42	/*
	43	* Create a new indirect link
	44	*
9bccf70c A	45	* An indirect link is a reference to a data node. The only useable
	46	* fields in the link are the link number, parentID, name and text
	47	* encoding. All other catalog fields are ignored.
1c79356b A	48	*/
1c79356b A	49	static int
9bccf70c A	50	createindirectlink(struct hfsmount *hfsmp, u_int32_t linknum,
9bccf70c A	51	u_int32_t linkparid, char linkName, cnid_t linkcnid)
1c79356b	52	{
9bccf70c A	53	struct FndrFileInfo *fip;
	54	struct cat_desc desc;
	55	struct cat_attr attr;
1c79356b A	56	int result;
1c79356b A	57
9bccf70c A	58	/* Setup the descriptor */
	59	bzero(&desc, sizeof(desc));
	60	desc.cd_nameptr = linkName;
	61	desc.cd_namelen = strlen(linkName);
	62	desc.cd_parentcnid = linkparid;
1c79356b	63
9bccf70c A	64	/* Setup the default attributes */
	65	bzero(&attr, sizeof(attr));
	66
	67	/* links are matched to data nodes by link ID and to volumes by create date */
	68	attr.ca_rdev = linknum; /* note: cat backend overloads ca_rdev to be the linknum when nlink = 0 */
	69	attr.ca_itime = HFSTOVCB(hfsmp)->vcbCrDate;
	70	attr.ca_mode = S_IFREG;
1c79356b	71
9bccf70c A	72	fip = (struct FndrFileInfo *)&attr.ca_finderinfo;
	73	fip->fdType = SWAP_BE32 (kHardLinkFileType); /* 'hlnk' */
	74	fip->fdCreator = SWAP_BE32 (kHFSPlusCreator); /* 'hfs+' */
	75	fip->fdFlags = SWAP_BE16 (kHasBeenInited);
1c79356b	76
9bccf70c A	77	/* Create the indirect link directly in the catalog */
9bccf70c A	78	result = cat_create(hfsmp, &desc, &attr, NULL);
1c79356b	79
b4c24cb9	80	if (result == 0 && linkcnid != NULL)
9bccf70c	81	*linkcnid = attr.ca_fileid;
1c79356b A	82
	83	return (result);
	84	}
	85
	86
	87	/*
9bccf70c	88	* 2 locks are needed (dvp and vp)
1c79356b A	89	* also need catalog lock
	90	*
	91	* caller's responsibility:
	92	* componentname cleanup
9bccf70c	93	* unlocking dvp and vp
1c79356b A	94	*/
1c79356b A	95	static int
9bccf70c A	96	hfs_makelink(struct hfsmount hfsmp, struct cnode cp, struct cnode *dcp,
9bccf70c A	97	struct componentname *cnp)
1c79356b	98	{
91447636 A	99	vfs_context_t ctx = cnp->cn_context;
91447636 A	100	struct proc *p = vfs_context_proc(ctx);
1c79356b	101	u_int32_t indnodeno = 0;
91447636	102	char inodename[32];
9bccf70c A	103	struct cat_desc to_desc;
9bccf70c A	104	int newlink = 0;
91447636	105	int lockflags;
1c79356b	106	int retval;
91447636 A	107	cat_cookie_t cookie;
91447636 A	108	cnid_t orig_cnid;
1c79356b	109
91447636 A	110	if (cur_link_id == 0) {
	111	cur_link_id = ((random() & 0x3fffffff) + 100);
	112	// printf("hfs: initializing cur link id to: 0x%.8x\n", cur_link_id);
	113	}
	114
1c79356b	115	/* We don't allow link nodes in our Private Meta Data folder! */
9bccf70c	116	if (dcp->c_fileid == hfsmp->hfs_privdir_desc.cd_cnid)
1c79356b A	117	return (EPERM);
1c79356b A	118
9bccf70c	119	if (hfs_freeblks(hfsmp, 0) == 0)
1c79356b A	120	return (ENOSPC);
1c79356b A	121
91447636	122	bzero(&cookie, sizeof(cat_cookie_t));
55e303ae A	123	/* Reserve some space in the Catalog file. */
	124	if ((retval = cat_preflight(hfsmp, (2 * CAT_CREATE)+ CAT_RENAME, &cookie, p))) {
	125	return (retval);
	126	}
	127
91447636 A	128	lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_EXCLUSIVE_LOCK);
	129
	130	// save off a copy of the current cnid so we can put
	131	// it back if we get errors down below
	132	orig_cnid = cp->c_desc.cd_cnid;
1c79356b A	133
	134	/*
	135	* If this is a new hardlink then we need to create the data
	136	* node (inode) and replace the original file with a link node.
	137	*/
9bccf70c A	138	if (cp->c_nlink == 2 && (cp->c_flag & C_HARDLINK) == 0) {
	139	newlink = 1;
	140	bzero(&to_desc, sizeof(to_desc));
	141	to_desc.cd_parentcnid = hfsmp->hfs_privdir_desc.cd_cnid;
	142	to_desc.cd_cnid = cp->c_fileid;
b4c24cb9	143
1c79356b A	144	do {
1c79356b A	145	/* get a unique indirect node number */
91447636 A	146	if (retval == 0) {
	147	indnodeno = cp->c_fileid;
	148	} else {
	149	indnodeno = cur_link_id++;
	150	}
	151
1c79356b A	152	MAKE_INODE_NAME(inodename, indnodeno);
	153
	154	/* move source file to data node directory */
9bccf70c A	155	to_desc.cd_nameptr = inodename;
	156	to_desc.cd_namelen = strlen(inodename);
	157
	158	retval = cat_rename(hfsmp, &cp->c_desc, &hfsmp->hfs_privdir_desc,
	159	&to_desc, NULL);
1c79356b	160
91447636 A	161	if (retval != 0 && retval != EEXIST) {
	162	printf("hfs_makelink: cat_rename to %s failed (%d). fileid %d\n",
	163	inodename, retval, cp->c_fileid);
	164	}
	165
9bccf70c A	166	} while (retval == EEXIST);
	167	if (retval)
	168	goto out;
1c79356b	169
9bccf70c A	170	/* Replace source file with link node */
	171	retval = createindirectlink(hfsmp, indnodeno, cp->c_parentcnid,
	172	cp->c_desc.cd_nameptr, &cp->c_desc.cd_cnid);
1c79356b	173	if (retval) {
91447636 A	174	/* put it source file back */
	175	int err;
	176
	177	// Put this back to what it was before.
	178	cp->c_desc.cd_cnid = orig_cnid;
	179
	180	err = cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
	181	if (err)
	182	panic("hfs_makelink: error %d from cat_rename backout 1", err);
	183	goto out;
1c79356b	184	}
9bccf70c A	185	cp->c_rdev = indnodeno;
	186	} else {
	187	indnodeno = cp->c_rdev;
	188	}
1c79356b A	189
	190	/*
	191	* Create a catalog entry for the new link (parentID + name).
	192	*/
9bccf70c A	193	retval = createindirectlink(hfsmp, indnodeno, dcp->c_fileid, cnp->cn_nameptr, NULL);
9bccf70c A	194	if (retval && newlink) {
91447636 A	195	int err;
	196
	197	/* Get rid of new link */
	198	(void) cat_delete(hfsmp, &cp->c_desc, &cp->c_attr);
	199
	200	// Put this back to what it was before.
	201	cp->c_desc.cd_cnid = orig_cnid;
	202
	203	/* Put the source file back */
	204	err = cat_rename(hfsmp, &to_desc, &dcp->c_desc, &cp->c_desc, NULL);
	205	if (err)
	206	panic("hfs_makelink: error %d from cat_rename backout 2", err);
	207
	208	goto out;
1c79356b A	209	}
	210
	211	/*
9bccf70c A	212	* Finally, if this is a new hardlink then:
	213	* - update HFS Private Data dir
	214	* - mark the cnode as a hard link
1c79356b	215	*/
9bccf70c	216	if (newlink) {
91447636 A	217	vnode_t vp;
	218
	219	if (retval != 0) {
	220	panic("hfs_makelink: retval %d but newlink = 1!\n", retval);
	221	}
	222
9bccf70c	223	hfsmp->hfs_privdir_attr.ca_entries++;
91447636 A	224	retval = cat_update(hfsmp, &hfsmp->hfs_privdir_desc,
	225	&hfsmp->hfs_privdir_attr, NULL, NULL);
	226	if (retval != 0) {
	227	panic("hfs_makelink: cat_update of privdir failed! (%d)\n",
	228	retval);
	229	}
9bccf70c	230	hfs_volupdate(hfsmp, VOL_MKFILE, 0);
91447636 A	231	cp->c_flag \|= C_HARDLINK;
	232	if ((vp = cp->c_vp) != NULLVP) {
	233	if (vnode_get(vp) == 0) {
	234	vnode_set_hard_link(vp);
	235	vnode_put(vp);
	236	}
	237	}
	238	if ((vp = cp->c_rsrc_vp) != NULLVP) {
	239	if (vnode_get(vp) == 0) {
	240	vnode_set_hard_link(vp);
	241	vnode_put(vp);
	242	}
	243	}
	244	cp->c_touch_chgtime = TRUE;
	245	cp->c_flag \|= C_FORCEUPDATE;
1c79356b	246	}
91447636	247	dcp->c_flag \|= C_FORCEUPDATE;
1c79356b A	248
1c79356b A	249	out:
91447636 A	250	hfs_systemfile_unlock(hfsmp, lockflags);
91447636 A	251
55e303ae	252	cat_postflight(hfsmp, &cookie, p);
1c79356b A	253	return (retval);
	254	}
	255
	256
	257	/*
	258	* link vnode call
	259	#% link vp U U U
	260	#% link tdvp L U U
	261	#
91447636	262	vnop_link {
1c79356b A	263	IN WILLRELE struct vnode *vp;
	264	IN struct vnode *targetPar_vp;
	265	IN struct componentname *cnp;
91447636	266	IN vfs_context_t context;
1c79356b A	267
1c79356b A	268	*/
55e303ae	269	__private_extern__
1c79356b	270	int
91447636	271	hfs_vnop_link(struct vnop_link_args *ap)
1c79356b	272	{
b4c24cb9	273	struct hfsmount *hfsmp;
1c79356b A	274	struct vnode *vp = ap->a_vp;
	275	struct vnode *tdvp = ap->a_tdvp;
	276	struct componentname *cnp = ap->a_cnp;
9bccf70c A	277	struct cnode *cp;
9bccf70c A	278	struct cnode *tdcp;
91447636 A	279	enum vtype v_type;
	280	int error, ret, lockflags;
	281	struct cat_desc cndesc;
1c79356b	282
91447636	283	if (VTOVCB(tdvp)->vcbSigWord != kHFSPlusSigWord) {
1c79356b	284	return err_link(ap); /* hfs disks don't support hard links */
91447636 A	285	}
91447636 A	286	if (VTOHFS(vp)->hfs_privdir_desc.cd_cnid == 0) {
1c79356b	287	return err_link(ap); /* no private metadata dir, no links possible */
1c79356b	288	}
91447636 A	289	if (vnode_mount(tdvp) != vnode_mount(vp)) {
	290	return (EXDEV);
	291	}
	292	if ((error = hfs_lockpair(VTOC(tdvp), VTOC(vp), HFS_EXCLUSIVE_LOCK))) {
	293	return (error);
	294	}
9bccf70c	295	tdcp = VTOC(tdvp);
91447636 A	296	cp = VTOC(vp);
91447636 A	297	hfsmp = VTOHFS(vp);
9bccf70c A	298
9bccf70c A	299	if (cp->c_nlink >= HFS_LINK_MAX) {
1c79356b	300	error = EMLINK;
91447636	301	goto out;
1c79356b	302	}
9bccf70c	303	if (cp->c_flags & (IMMUTABLE \| APPEND)) {
1c79356b	304	error = EPERM;
91447636	305	goto out;
1c79356b	306	}
91447636 A	307	if (cp->c_flag & (C_NOEXISTS \| C_DELETED)) {
	308	error = ENOENT;
	309	goto out;
	310	}
	311
	312	v_type = vnode_vtype(vp);
	313	if (v_type == VBLK \|\| v_type == VCHR) {
1c79356b	314	error = EINVAL; /* cannot link to a special file */
91447636	315	goto out;
1c79356b A	316	}
1c79356b A	317
91447636 A	318	if (hfs_start_transaction(hfsmp) != 0) {
	319	error = EINVAL; /* cannot link to a special file */
	320	goto out;
b4c24cb9 A	321	}
b4c24cb9 A	322
9bccf70c	323	cp->c_nlink++;
91447636	324	cp->c_touch_chgtime = TRUE;
b4c24cb9	325
91447636	326	error = hfs_makelink(hfsmp, cp, tdcp, cnp);
1c79356b	327	if (error) {
9bccf70c	328	cp->c_nlink--;
91447636	329	hfs_volupdate(hfsmp, VOL_UPDATE, 0);
9bccf70c	330	} else {
91447636 A	331	/* Invalidate negative cache entries in the destination directory */
	332	if (hfsmp->hfs_flags & HFS_CASE_SENSITIVE)
	333	cache_purge_negatives(tdvp);
	334
9bccf70c A	335	/* Update the target directory and volume stats */
	336	tdcp->c_nlink++;
	337	tdcp->c_entries++;
91447636 A	338	tdcp->c_touch_chgtime = TRUE;
	339	tdcp->c_touch_modtime = TRUE;
	340	tdcp->c_flag \|= C_FORCEUPDATE;
	341
	342	error = hfs_update(tdvp, 0);
	343	if (error) {
	344	panic("hfs_vnop_link: error updating tdvp 0x%x\n", tdvp);
	345	}
b4c24cb9 A	346
b4c24cb9 A	347	hfs_volupdate(hfsmp, VOL_MKFILE,
9bccf70c	348	(tdcp->c_cnid == kHFSRootFolderID));
1c79356b	349	}
b4c24cb9	350
91447636	351	cp->c_flag \|= C_FORCEUPDATE; // otherwise hfs_update() might skip the update
b4c24cb9	352
91447636 A	353	if ((ret = hfs_update(vp, TRUE)) != 0) {
91447636 A	354	panic("hfs_vnop_link: error %d updating vp @ 0x%x\n", ret, vp);
55e303ae	355	}
91447636 A	356
91447636 A	357	hfs_end_transaction(hfsmp);
55e303ae A	358
	359	HFS_KNOTE(vp, NOTE_LINK);
	360	HFS_KNOTE(tdvp, NOTE_WRITE);
91447636 A	361	out:
91447636 A	362	hfs_unlockpair(tdcp, cp);
1c79356b A	363	return (error);
1c79356b A	364	}