xnu-792.1.5.tar.gz

[apple/xnu.git] / bsd / hfs / hfs_cnode.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@
 */
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/time.h>
#include <sys/ubc.h>
#include <sys/quota.h>
#include <sys/kdebug.h>

#include <kern/locks.h>

#include <miscfs/specfs/specdev.h>
#include <miscfs/fifofs/fifo.h>

#include <hfs/hfs.h>
#include <hfs/hfs_catalog.h>
#include <hfs/hfs_cnode.h>
#include <hfs/hfs_quota.h>

extern int prtactive;

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

static int  hfs_filedone(struct vnode *vp, vfs_context_t context);

static void  hfs_reclaim_cnode(struct cnode *);

static int  hfs_valid_cnode(struct hfsmount *, struct vnode *, struct componentname *, cnid_t);

static int hfs_isordered(struct cnode *, struct cnode *);

int hfs_vnop_inactive(struct vnop_inactive_args *);

int hfs_vnop_reclaim(struct vnop_reclaim_args *);


/*
 * Last reference to an cnode.  If necessary, write or delete it.
 */
__private_extern__
int
hfs_vnop_inactive(struct vnop_inactive_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct cnode *cp;
        struct hfsmount *hfsmp = VTOHFS(vp);
        struct proc *p = vfs_context_proc(ap->a_context);
        int error = 0;
        int recycle = 0;
        int forkcount = 0;
        int truncated = 0;
        int started_tr = 0;
        int took_trunc_lock = 0;
        cat_cookie_t cookie;
        int cat_reserve = 0;
        int lockflags;
        enum vtype v_type;

        v_type = vnode_vtype(vp);
        cp = VTOC(vp);

        if ((hfsmp->hfs_flags & HFS_READ_ONLY) || vnode_issystem(vp)) {
                return (0);
        }
        /*
         * Ignore nodes related to stale file handles.
         */
        if (cp->c_mode == 0) {
                vnode_recycle(vp);
                return (0);
        }

        if ((v_type == VREG) &&
            (ISSET(cp->c_flag, C_DELETED) || VTOF(vp)->ff_blocks)) {
                hfs_lock_truncate(cp, TRUE);
                took_trunc_lock = 1;
        }

        /*
         * We do the ubc_setsize before we take the cnode
         * lock and before the hfs_truncate (since we'll
         * be inside a transaction).
         */
        if ((v_type == VREG || v_type == VLNK) &&
            (cp->c_flag & C_DELETED) &&
            (VTOF(vp)->ff_blocks != 0)) {
                ubc_setsize(vp, 0);
        }

        (void) hfs_lock(cp, HFS_FORCE_LOCK);

        if (v_type == VREG && !ISSET(cp->c_flag, C_DELETED) && VTOF(vp)->ff_blocks) {
                hfs_filedone(vp, ap->a_context);
        }
        /* 
         * Remove any directory hints
         */
        if (v_type == VDIR)
                hfs_reldirhints(cp, 0);

        if (cp->c_datafork)
                ++forkcount;
        if (cp->c_rsrcfork)
                ++forkcount;

        /* If needed, get rid of any fork's data for a deleted file */
        if ((v_type == VREG || v_type == VLNK) && (cp->c_flag & C_DELETED)) {
                if (VTOF(vp)->ff_blocks != 0) {
                    // start the transaction out here so that
                    // the truncate and the removal of the file
                    // are all in one transaction.  otherwise
                    // because this cnode is marked for deletion
                    // the truncate won't cause the catalog entry
                    // to get updated which means that we could
                    // free blocks but still keep a reference to
                    // them in the catalog entry and then double
                    // free them later.
                    //
                    if (hfs_start_transaction(hfsmp) != 0) {
                        error = EINVAL;
                        goto out;
                    }
                    started_tr = 1;
                    
                        /*
                         * Since we're already inside a transaction,
                         * tell hfs_truncate to skip the ubc_setsize.
                         */
                        error = hfs_truncate(vp, (off_t)0, IO_NDELAY, 1, ap->a_context);
                        if (error)
                                goto out;
                        truncated = 1;
                }
                recycle = 1;
        }

        /*
         * Check for a postponed deletion.
         * (only delete cnode when the last fork goes inactive)
         */
        if ((cp->c_flag & C_DELETED) && (forkcount <= 1)) {                     
                /*
                 * Mark cnode in transit so that no one can get this 
                 * cnode from cnode hash.
                 */
                hfs_chash_mark_in_transit(cp);

                cp->c_flag &= ~C_DELETED;
                cp->c_flag |= C_NOEXISTS;   // XXXdbg
                cp->c_rdev = 0;

                if (started_tr == 0) {
                    if (hfs_start_transaction(hfsmp) != 0) {
                        error = EINVAL;
                        goto out;
                    }
                    started_tr = 1;
                }
                
                /*
                 * Reserve some space in the Catalog file.
                 */
                if ((error = cat_preflight(hfsmp, CAT_DELETE, &cookie, p))) {
                        goto out;
                }
                cat_reserve = 1;

                lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG | SFL_ATTRIBUTE, HFS_EXCLUSIVE_LOCK);

                if (cp->c_blocks > 0)
                        printf("hfs_inactive: attempting to delete a non-empty file!");


                //
                // release the name pointer in the descriptor so that
                // cat_delete() will use the file-id to do the deletion.
                // in the case of hard links this is imperative (in the
                // case of regular files the fileid and cnid are the
                // same so it doesn't matter).
                //
                cat_releasedesc(&cp->c_desc);
                
                /*
                 * The descriptor name may be zero,
                 * in which case the fileid is used.
                 */
                error = cat_delete(hfsmp, &cp->c_desc, &cp->c_attr);
                
                if (error && truncated && (error != ENXIO))
                        printf("hfs_inactive: couldn't delete a truncated file!");

                /* Update HFS Private Data dir */
                if (error == 0) {
                        hfsmp->hfs_privdir_attr.ca_entries--;
                        (void)cat_update(hfsmp, &hfsmp->hfs_privdir_desc,
                                &hfsmp->hfs_privdir_attr, NULL, NULL);
                }

                if (error == 0) {
                        /* Delete any attributes, ignore errors */
                        (void) hfs_removeallattr(hfsmp, cp->c_fileid);
                }

                hfs_systemfile_unlock(hfsmp, lockflags);

                if (error)
                        goto out;

#if QUOTA
                (void)hfs_chkiq(cp, -1, NOCRED, 0);
#endif /* QUOTA */

                cp->c_mode = 0;
                cp->c_flag |= C_NOEXISTS;
                cp->c_touch_chgtime = TRUE;
                cp->c_touch_modtime = TRUE;

                if (error == 0)
                        hfs_volupdate(hfsmp, VOL_RMFILE, 0);
        }

        if ((cp->c_flag & C_MODIFIED) ||
            cp->c_touch_acctime || cp->c_touch_chgtime || cp->c_touch_modtime) {
                hfs_update(vp, 0);
        }
out:
        if (cat_reserve)
                cat_postflight(hfsmp, &cookie, p);

        // XXXdbg - have to do this because a goto could have come here
        if (started_tr) {
            hfs_end_transaction(hfsmp);
            started_tr = 0;
        }

        hfs_unlock(cp);

        if (took_trunc_lock)
                hfs_unlock_truncate(cp);

        /*
         * If we are done with the vnode, reclaim it
         * so that it can be reused immediately.
         */
        if (cp->c_mode == 0 || recycle)
                vnode_recycle(vp);

        return (error);
}

/*
 * File clean-up (zero fill and shrink peof).
 */
static int
hfs_filedone(struct vnode *vp, vfs_context_t context)
{
        struct cnode *cp;
        struct filefork *fp;
        struct hfsmount *hfsmp;
        off_t leof;
        u_long blks, blocksize;

        cp = VTOC(vp);
        fp = VTOF(vp);
        hfsmp = VTOHFS(vp);
        leof = fp->ff_size;

        if ((hfsmp->hfs_flags & HFS_READ_ONLY) || (fp->ff_blocks == 0))
                return (0);

        hfs_unlock(cp);
        (void) cluster_push(vp, IO_CLOSE);
        hfs_lock(cp, HFS_FORCE_LOCK);

        /*
         * Explicitly zero out the areas of file
         * that are currently marked invalid.
         */
        while (!CIRCLEQ_EMPTY(&fp->ff_invalidranges)) {
                struct rl_entry *invalid_range = CIRCLEQ_FIRST(&fp->ff_invalidranges);
                off_t start = invalid_range->rl_start;
                off_t end = invalid_range->rl_end;
        
                /* The range about to be written must be validated
                 * first, so that VNOP_BLOCKMAP() will return the
                 * appropriate mapping for the cluster code:
                 */
                rl_remove(start, end, &fp->ff_invalidranges);

                hfs_unlock(cp);
                (void) cluster_write(vp, (struct uio *) 0,
                                     leof, end + 1, start, (off_t)0,
                                     IO_HEADZEROFILL | IO_NOZERODIRTY | IO_NOCACHE);
                hfs_lock(cp, HFS_FORCE_LOCK);
                cp->c_flag |= C_MODIFIED;
        }
        cp->c_flag &= ~C_ZFWANTSYNC;
        cp->c_zftimeout = 0;
        blocksize = VTOVCB(vp)->blockSize;
        blks = leof / blocksize;
        if (((off_t)blks * (off_t)blocksize) != leof)
                blks++;
        /*
         * Shrink the peof to the smallest size neccessary to contain the leof.
         */
        if (blks < fp->ff_blocks)
                (void) hfs_truncate(vp, leof, IO_NDELAY, 0, context);
        hfs_unlock(cp);
        (void) cluster_push(vp, IO_CLOSE);
        hfs_lock(cp, HFS_FORCE_LOCK);
        
        /*
         * If the hfs_truncate didn't happen to flush the vnode's
         * information out to disk, force it to be updated now that
         * all invalid ranges have been zero-filled and validated:
         */
        if (cp->c_flag & C_MODIFIED) {
                hfs_update(vp, 0);
        }
        return (0);
}


/*
 * Reclaim a cnode so that it can be used for other purposes.
 */
__private_extern__
int
hfs_vnop_reclaim(struct vnop_reclaim_args *ap)
{
        struct vnode *vp = ap->a_vp;
        struct cnode *cp;
        struct filefork *fp = NULL;
        struct filefork *altfp = NULL;
        int reclaim_cnode = 0;

        (void) hfs_lock(VTOC(vp), HFS_FORCE_LOCK);
        cp = VTOC(vp);

        /*
         * Keep track of an inactive hot file.
         */
        if (!vnode_isdir(vp) && !vnode_issystem(vp))
                (void) hfs_addhotfile(vp);

        vnode_removefsref(vp);

        /*
         * Find file fork for this vnode (if any)
         * Also check if another fork is active
         */
        if (cp->c_vp == vp) {
                fp = cp->c_datafork;
                altfp = cp->c_rsrcfork;

                cp->c_datafork = NULL;
                cp->c_vp = NULL;
        } else if (cp->c_rsrc_vp == vp) {
                fp = cp->c_rsrcfork;
                altfp = cp->c_datafork;

                cp->c_rsrcfork = NULL;
                cp->c_rsrc_vp = NULL;
        } else {
                panic("hfs_vnop_reclaim: vp points to wrong cnode\n");
        }
        /*
         * On the last fork, remove the cnode from its hash chain.
         */
        if (altfp == NULL) {
                /* If we can't remove it then the cnode must persist! */
                if (hfs_chashremove(cp) == 0)
                        reclaim_cnode = 1;
                /* 
                 * Remove any directory hints
                 */
                if (vnode_isdir(vp)) {
                        hfs_reldirhints(cp, 0);
                }
        }
        /* Release the file fork and related data */
        if (fp) {
                /* Dump cached symlink data */
                if (vnode_islnk(vp) && (fp->ff_symlinkptr != NULL)) {
                        FREE(fp->ff_symlinkptr, M_TEMP);
                }               
                FREE_ZONE(fp, sizeof(struct filefork), M_HFSFORK);
        }

        /* 
         * If there was only one active fork then we can release the cnode.
         */
        if (reclaim_cnode) {
                hfs_chashwakeup(cp, H_ALLOC | H_TRANSIT);
                hfs_reclaim_cnode(cp);
        } else /* cnode in use */ {
                hfs_unlock(cp);
        }

        vnode_clearfsnode(vp);
        return (0);
}


extern int (**hfs_vnodeop_p) (void *);
extern int (**hfs_specop_p)  (void *);
extern int (**hfs_fifoop_p)  (void *);

/*
 * hfs_getnewvnode - get new default vnode
 *
 * The vnode is returned with an iocount and the cnode locked
 */
__private_extern__
int
hfs_getnewvnode(
        struct hfsmount *hfsmp,
        struct vnode *dvp,
        struct componentname *cnp,
        struct cat_desc *descp,
        int wantrsrc,
        struct cat_attr *attrp,
        struct cat_fork *forkp,
        struct vnode **vpp)
{
        struct mount *mp = HFSTOVFS(hfsmp);
        struct vnode *vp = NULL;
        struct vnode **cvpp;
        struct vnode *tvp = NULLVP;
        struct cnode *cp = NULL;
        struct filefork *fp = NULL;
        int i;
        int retval;
        int issystemfile;
        struct vnode_fsparam vfsp;
        enum vtype vtype;

        if (attrp->ca_fileid == 0) {
                *vpp = NULL;
                return (ENOENT);
        }

#if !FIFO
        if (IFTOVT(attrp->ca_mode) == VFIFO) {
                *vpp = NULL;
                return (ENOTSUP);
        }
#endif
        vtype = IFTOVT(attrp->ca_mode);
        issystemfile = (descp->cd_flags & CD_ISMETA) && (vtype == VREG);

        /*
         * Get a cnode (new or existing)
         * skip getting the cnode lock if we are getting resource fork (wantrsrc == 2)
         */
        cp = hfs_chash_getcnode(hfsmp->hfs_raw_dev, attrp->ca_fileid, vpp, wantrsrc, (wantrsrc == 2));

        /* Hardlinks may need an updated catalog descriptor */
        if ((cp->c_flag & C_HARDLINK) && descp->cd_nameptr && descp->cd_namelen > 0) {
                replace_desc(cp, descp);
        }
        /* Check if we found a matching vnode */
        if (*vpp != NULL)
                return (0);

        /*
         * If this is a new cnode then initialize it.
         */
        if (ISSET(cp->c_hflag, H_ALLOC)) {
                lck_rw_init(&cp->c_truncatelock, hfs_rwlock_group, hfs_lock_attr);

                /* Make sure its still valid (ie exists on disk). */
                if (!hfs_valid_cnode(hfsmp, dvp, (wantrsrc ? NULL : cnp), cp->c_fileid)) {
                        hfs_chash_abort(cp);
                        hfs_reclaim_cnode(cp);
                        *vpp = NULL;
                        return (ENOENT);
                }
                bcopy(attrp, &cp->c_attr, sizeof(struct cat_attr));
                bcopy(descp, &cp->c_desc, sizeof(struct cat_desc));

                /* The name was inherited so clear descriptor state... */
                descp->cd_namelen = 0;
                descp->cd_nameptr = NULL;
                descp->cd_flags &= ~CD_HASBUF;

                /* Tag hardlinks */
                if (IFTOVT(cp->c_mode) == VREG &&
                    (descp->cd_cnid != attrp->ca_fileid)) {
                        cp->c_flag |= C_HARDLINK;
                }

                /* Take one dev reference for each non-directory cnode */
                if (IFTOVT(cp->c_mode) != VDIR) {
                        cp->c_devvp = hfsmp->hfs_devvp;
                        vnode_ref(cp->c_devvp);
                }
#if QUOTA
                for (i = 0; i < MAXQUOTAS; i++)
                        cp->c_dquot[i] = NODQUOT;
#endif /* QUOTA */
        }

        if (IFTOVT(cp->c_mode) == VDIR) {
                if (cp->c_vp != NULL)
                        panic("hfs_getnewvnode: orphaned vnode (data)");
                cvpp = &cp->c_vp;
        } else {
                if (forkp && attrp->ca_blocks < forkp->cf_blocks)
                        panic("hfs_getnewvnode: bad ca_blocks (too small)");
                /*
                 * Allocate and initialize a file fork...
                 */
                MALLOC_ZONE(fp, struct filefork *, sizeof(struct filefork),
                        M_HFSFORK, M_WAITOK);
                fp->ff_cp = cp;
                if (forkp)
                        bcopy(forkp, &fp->ff_data, sizeof(struct cat_fork));
                else
                        bzero(&fp->ff_data, sizeof(struct cat_fork));
                rl_init(&fp->ff_invalidranges);
                fp->ff_sysfileinfo = 0;

                if (wantrsrc) {
                        if (cp->c_rsrcfork != NULL)
                                panic("hfs_getnewvnode: orphaned rsrc fork");
                        if (cp->c_rsrc_vp != NULL)
                                panic("hfs_getnewvnode: orphaned vnode (rsrc)");
                        cp->c_rsrcfork = fp;
                        cvpp = &cp->c_rsrc_vp;
                        if ( (tvp = cp->c_vp) != NULLVP )
                                cp->c_flag |= C_NEED_DVNODE_PUT;
                } else {
                        if (cp->c_datafork != NULL)
                                panic("hfs_getnewvnode: orphaned data fork");
                        if (cp->c_vp != NULL)
                                panic("hfs_getnewvnode: orphaned vnode (data)");
                        cp->c_datafork = fp;
                        cvpp = &cp->c_vp;
                        if ( (tvp = cp->c_rsrc_vp) != NULLVP)
                                cp->c_flag |= C_NEED_RVNODE_PUT;
                }
        }
        if (tvp != NULLVP) {
                /*
                 * grab an iocount on the vnode we weren't
                 * interested in (i.e. we want the resource fork
                 * but the cnode already has the data fork)
                 * to prevent it from being
                 * recycled by us when we call vnode_create
                 * which will result in a deadlock when we
                 * try to take the cnode lock in hfs_vnop_fsync or
                 * hfs_vnop_reclaim... vnode_get can be called here
                 * because we already hold the cnode lock which will
                 * prevent the vnode from changing identity until
                 * we drop it.. vnode_get will not block waiting for
                 * a change of state... however, it will return an
                 * error if the current iocount == 0 and we've already
                 * started to terminate the vnode... we don't need/want to
                 * grab an iocount in the case since we can't cause
                 * the fileystem to be re-entered on this thread for this vp
                 *
                 * the matching vnode_put will happen in hfs_unlock
                 * after we've dropped the cnode lock
                 */
                if ( vnode_get(tvp) != 0)
                        cp->c_flag &= ~(C_NEED_RVNODE_PUT | C_NEED_DVNODE_PUT);
        }
        vfsp.vnfs_mp = mp;
        vfsp.vnfs_vtype = vtype;
        vfsp.vnfs_str = "hfs";
        vfsp.vnfs_dvp = dvp;
        vfsp.vnfs_fsnode = cp;
        vfsp.vnfs_cnp = cnp;
        if (vtype == VFIFO )
                vfsp.vnfs_vops = hfs_fifoop_p;
        else if (vtype == VBLK || vtype == VCHR)
                vfsp.vnfs_vops = hfs_specop_p;
        else
                vfsp.vnfs_vops = hfs_vnodeop_p;
                
        if (vtype == VBLK || vtype == VCHR)
                vfsp.vnfs_rdev = attrp->ca_rdev;
        else
                vfsp.vnfs_rdev = 0;

        if (forkp) 
                vfsp.vnfs_filesize = forkp->cf_size;
        else
                vfsp.vnfs_filesize = 0;

        if (dvp && cnp && (cnp->cn_flags & MAKEENTRY))
                vfsp.vnfs_flags = 0;
        else
                vfsp.vnfs_flags = VNFS_NOCACHE;

        /* Tag system files */
        vfsp.vnfs_marksystem = issystemfile;

        /* Tag root directory */
        if (descp->cd_cnid == kHFSRootFolderID)
                vfsp.vnfs_markroot = 1;
        else    
                vfsp.vnfs_markroot = 0;

        if ((retval = vnode_create(VNCREATE_FLAVOR, VCREATESIZE, &vfsp, cvpp))) {
                if (fp) {
                        if (fp == cp->c_datafork)
                                cp->c_datafork = NULL;
                        else
                                cp->c_rsrcfork = NULL;

                        FREE_ZONE(fp, sizeof(struct filefork), M_HFSFORK);
                }
                /*
                 * If this is a newly created cnode or a vnode reclaim
                 * occurred during the attachment, then cleanup the cnode.
                 */
                if ((cp->c_vp == NULL) && (cp->c_rsrc_vp == NULL)) {
                        hfs_chash_abort(cp);
                        hfs_reclaim_cnode(cp);
                } else {
                        hfs_chashwakeup(cp, H_ALLOC | H_ATTACH);
                        hfs_unlock(cp);
                }
                *vpp = NULL;
                return (retval);
        }
        vp = *cvpp;
        vnode_addfsref(vp);
        vnode_settag(vp, VT_HFS);
        if (cp->c_flag & C_HARDLINK)
                vnode_set_hard_link(vp);
        hfs_chashwakeup(cp, H_ALLOC | H_ATTACH);

        /*
         * Stop tracking an active hot file.
         */
        if (!vnode_isdir(vp) && !vnode_issystem(vp))
                (void) hfs_removehotfile(vp);

        *vpp = vp;
        return (0);
}


static void
hfs_reclaim_cnode(struct cnode *cp)
{
#if QUOTA
        int i;

        for (i = 0; i < MAXQUOTAS; i++) {
                if (cp->c_dquot[i] != NODQUOT) {
                        dqreclaim(cp->c_dquot[i]);
                        cp->c_dquot[i] = NODQUOT;
                }
        }
#endif /* QUOTA */

        if (cp->c_devvp) {
                struct vnode *tmp_vp = cp->c_devvp;

                cp->c_devvp = NULL;
                vnode_rele(tmp_vp);
        }

        /* 
         * If the descriptor has a name then release it
         */
        if (cp->c_desc.cd_flags & CD_HASBUF) {
                char *nameptr;

                nameptr = cp->c_desc.cd_nameptr;
                cp->c_desc.cd_nameptr = 0;
                cp->c_desc.cd_flags &= ~CD_HASBUF;
                cp->c_desc.cd_namelen = 0;
                vfs_removename(nameptr);
        }

        lck_rw_destroy(&cp->c_rwlock, hfs_rwlock_group);
        lck_rw_destroy(&cp->c_truncatelock, hfs_rwlock_group);
        bzero(cp, sizeof(struct cnode));
        FREE_ZONE(cp, sizeof(struct cnode), M_HFSNODE);
}


static int
hfs_valid_cnode(struct hfsmount *hfsmp, struct vnode *dvp, struct componentname *cnp, cnid_t cnid)
{
        struct cat_attr attr;
        struct cat_desc cndesc;
        int stillvalid = 0;
        int lockflags;

        /* System files are always valid */
        if (cnid < kHFSFirstUserCatalogNodeID)
                return (1);

        /* XXX optimization:  check write count in dvp */

        lockflags = hfs_systemfile_lock(hfsmp, SFL_CATALOG, HFS_SHARED_LOCK);

        if (dvp && cnp) {
                bzero(&cndesc, sizeof(cndesc));
                cndesc.cd_nameptr = cnp->cn_nameptr;
                cndesc.cd_namelen = cnp->cn_namelen;
                cndesc.cd_parentcnid = VTOC(dvp)->c_cnid;
                cndesc.cd_hint = VTOC(dvp)->c_childhint;

                if ((cat_lookup(hfsmp, &cndesc, 0, NULL, &attr, NULL, NULL) == 0) &&
                    (cnid == attr.ca_fileid)) {
                        stillvalid = 1;
                }
        } else {
                if (cat_idlookup(hfsmp, cnid, NULL, NULL, NULL) == 0) {
                        stillvalid = 1;
                }
        }
        hfs_systemfile_unlock(hfsmp, lockflags);

        return (stillvalid);
}

/*
 * Touch cnode times based on c_touch_xxx flags
 *
 * cnode must be locked exclusive
 *
 * This will also update the volume modify time
 */
__private_extern__
void
hfs_touchtimes(struct hfsmount *hfsmp, struct cnode* cp)
{
        /* HFS Standard doesn't support access times */
        if (hfsmp->hfs_flags & HFS_STANDARD) {
                cp->c_touch_acctime = FALSE;
        }

        if (cp->c_touch_acctime || cp->c_touch_chgtime || cp->c_touch_modtime) {
                struct timeval tv;
                int touchvol = 0;

                microtime(&tv);
                    
                if (cp->c_touch_acctime) {
                        cp->c_atime = tv.tv_sec;
                        /*
                         * When the access time is the only thing changing
                         * then make sure its sufficiently newer before
                         * committing it to disk.
                         */
                        if ((((u_int32_t)cp->c_atime - (u_int32_t)(cp)->c_attr.ca_atimeondisk) >
                              ATIME_ONDISK_ACCURACY)) {
                                cp->c_flag |= C_MODIFIED;
                        }
                        cp->c_touch_acctime = FALSE;
                }
                if (cp->c_touch_modtime) {
                        cp->c_mtime = tv.tv_sec;
                        cp->c_touch_modtime = FALSE;
                        cp->c_flag |= C_MODIFIED;
                        touchvol = 1;
#if 1
                        /*
                         * HFS dates that WE set must be adjusted for DST
                         */
                        if ((hfsmp->hfs_flags & HFS_STANDARD) && gTimeZone.tz_dsttime) {
                                cp->c_mtime += 3600;
                        }
#endif
                }
                if (cp->c_touch_chgtime) {
                        cp->c_ctime = tv.tv_sec;
                        cp->c_touch_chgtime = FALSE;
                        cp->c_flag |= C_MODIFIED;
                        touchvol = 1;
                }

                /* Touch the volume modtime if needed */
                if (touchvol) {
                        HFSTOVCB(hfsmp)->vcbFlags |= 0xFF00;
                        HFSTOVCB(hfsmp)->vcbLsMod = tv.tv_sec;
                }
        }
}

/*
 * Lock a cnode.
 */
__private_extern__
int
hfs_lock(struct cnode *cp, enum hfslocktype locktype)
{
        void * thread = current_thread();

        /* System files need to keep track of owner */
        if ((cp->c_fileid < kHFSFirstUserCatalogNodeID) &&
            (cp->c_fileid > kHFSRootFolderID) &&
            (locktype != HFS_SHARED_LOCK)) {

                /*
                 * The extents and bitmap file locks support
                 * recursion and are always taken exclusive.
                 */
                if (cp->c_fileid == kHFSExtentsFileID ||
                    cp->c_fileid == kHFSAllocationFileID) {
                        if (cp->c_lockowner == thread) {
                                cp->c_syslockcount++;
                        } else {
                                lck_rw_lock_exclusive(&cp->c_rwlock);
                                cp->c_lockowner = thread;
                                cp->c_syslockcount = 1;
                        }
                } else {
                        lck_rw_lock_exclusive(&cp->c_rwlock);
                        cp->c_lockowner = thread;
                }
        } else if (locktype == HFS_SHARED_LOCK) {
                lck_rw_lock_shared(&cp->c_rwlock);
                cp->c_lockowner = HFS_SHARED_OWNER;
        } else {
                lck_rw_lock_exclusive(&cp->c_rwlock);
                cp->c_lockowner = thread;
        }
        /*
         * Skip cnodes that no longer exist (were deleted).
         */
        if ((locktype != HFS_FORCE_LOCK) &&
            ((cp->c_desc.cd_flags & CD_ISMETA) == 0) &&
            (cp->c_flag & C_NOEXISTS)) {
                hfs_unlock(cp);
                return (ENOENT);
        }
        return (0);
}

/*
 * Lock a pair of cnodes.
 */
__private_extern__
int
hfs_lockpair(struct cnode *cp1, struct cnode *cp2, enum hfslocktype locktype)
{
        struct cnode *first, *last;
        int error;

        /*
         * If cnodes match then just lock one.
         */
        if (cp1 == cp2) {
                return hfs_lock(cp1, locktype);
        }

        /*
         * Lock in cnode parent-child order (if there is a relationship);
         * otherwise lock in cnode address order.
         */
        if ((IFTOVT(cp1->c_mode) == VDIR) && (cp1->c_fileid == cp2->c_parentcnid)) {
                first = cp1;
                last = cp2;
        } else if (cp1 < cp2) {
                first = cp1;
                last = cp2;
        } else {
                first = cp2;
                last = cp1;
        }

        if ( (error = hfs_lock(first, locktype))) {
                return (error);
        }
        if ( (error = hfs_lock(last, locktype))) {
                hfs_unlock(first);
                return (error);
        }
        return (0);
}

/*
 * Check ordering of two cnodes. Return true if they are are in-order.
 */
static int
hfs_isordered(struct cnode *cp1, struct cnode *cp2)
{
        if (cp1 == cp2)
                return (0);
        if (cp1 == NULL || cp2 == (struct cnode *)0xffffffff)
                return (1);
        if (cp2 == NULL || cp1 == (struct cnode *)0xffffffff)
                return (0);
        if (cp1->c_fileid == cp2->c_parentcnid)
                return (1);  /* cp1 is the parent and should go first */
        if (cp2->c_fileid == cp1->c_parentcnid)
                return (0);  /* cp1 is the child and should go last */

        return (cp1 < cp2);  /* fall-back is to use address order */
}

/*
 * Acquire 4 cnode locks.
 *   - locked in cnode parent-child order (if there is a relationship)
 *     otherwise lock in cnode address order (lesser address first).
 *   - all or none of the locks are taken
 *   - only one lock taken per cnode (dup cnodes are skipped)
 *   - some of the cnode pointers may be null
 */
__private_extern__
int
hfs_lockfour(struct cnode *cp1, struct cnode *cp2, struct cnode *cp3,
             struct cnode *cp4, enum hfslocktype locktype)
{
        struct cnode * a[3];
        struct cnode * b[3];
        struct cnode * list[4];
        struct cnode * tmp;
        int i, j, k;
        int error;

        if (hfs_isordered(cp1, cp2)) {
                a[0] = cp1; a[1] = cp2;
        } else {
                a[0] = cp2; a[1] = cp1;
        }
        if (hfs_isordered(cp3, cp4)) {
                b[0] = cp3; b[1] = cp4;
        } else {
                b[0] = cp4; b[1] = cp3;
        }
        a[2] = (struct cnode *)0xffffffff;  /* sentinel value */
        b[2] = (struct cnode *)0xffffffff;  /* sentinel value */

        /*
         * Build the lock list, skipping over duplicates
         */
        for (i = 0, j = 0, k = 0; (i < 2 || j < 2); ) {
                tmp = hfs_isordered(a[i], b[j]) ? a[i++] : b[j++];
                if (k == 0 || tmp != list[k-1])
                        list[k++] = tmp;
        }

        /*
         * Now we can lock using list[0 - k].
         * Skip over NULL entries.
         */
        for (i = 0; i < k; ++i) {
                if (list[i])
                        if ((error = hfs_lock(list[i], locktype))) {
                                /* Drop any locks we acquired. */
                                while (--i >= 0) {
                                        if (list[i])
                                                hfs_unlock(list[i]);
                                }
                                return (error);
                        }
        }
        return (0);
}


/*
 * Unlock a cnode.
 */
__private_extern__
void
hfs_unlock(struct cnode *cp)
{
        vnode_t rvp = NULLVP;
        vnode_t dvp = NULLVP;

        /* System files need to keep track of owner */
        if ((cp->c_fileid < kHFSFirstUserCatalogNodeID) &&
            (cp->c_fileid > kHFSRootFolderID) &&
            (cp->c_datafork != NULL)) {
                /*
                 * The extents and bitmap file locks support
                 * recursion and are always taken exclusive.
                 */
                if (cp->c_fileid == kHFSExtentsFileID ||
                    cp->c_fileid == kHFSAllocationFileID) {
                        if (--cp->c_syslockcount > 0) {
                                return;
                        }
                }
        }
        if (cp->c_flag & C_NEED_DVNODE_PUT)
                dvp = cp->c_vp;

        if (cp->c_flag & C_NEED_RVNODE_PUT)
                rvp = cp->c_rsrc_vp;

        cp->c_flag &= ~(C_NEED_DVNODE_PUT | C_NEED_RVNODE_PUT);

        cp-> c_lockowner = NULL;
        lck_rw_done(&cp->c_rwlock);

        if (dvp)
                vnode_put(dvp);
        if (rvp)
                vnode_put(rvp);
}

/*
 * Unlock a pair of cnodes.
 */
__private_extern__
void
hfs_unlockpair(struct cnode *cp1, struct cnode *cp2)
{
        hfs_unlock(cp1);
        if (cp2 != cp1)
                hfs_unlock(cp2);
}

/*
 * Unlock a group of cnodes.
 */
__private_extern__
void
hfs_unlockfour(struct cnode *cp1, struct cnode *cp2, struct cnode *cp3, struct cnode *cp4)
{
        struct cnode * list[4];
        int i, k = 0;

        if (cp1) {
                hfs_unlock(cp1);
                list[k++] = cp1;
        }
        if (cp2) {
                for (i = 0; i < k; ++i) {
                        if (list[i] == cp2)
                                goto skip1;
                }
                hfs_unlock(cp2);
                list[k++] = cp2;
        }
skip1:
        if (cp3) {
                for (i = 0; i < k; ++i) {
                        if (list[i] == cp3)
                                goto skip2;
                }
                hfs_unlock(cp3);
                list[k++] = cp3;
        }
skip2:
        if (cp4) {
                for (i = 0; i < k; ++i) {
                        if (list[i] == cp4)
                                return;
                }
                hfs_unlock(cp4);
        }
}


/*
 * Protect a cnode against a truncation.
 *
 * Used mainly by read/write since they don't hold the
 * cnode lock across calls to the cluster layer.
 *
 * The process doing a truncation must take the lock
 * exclusive. The read/write processes can take it
 * non-exclusive.
 */
__private_extern__
void
hfs_lock_truncate(struct cnode *cp, int exclusive)
{
        if (cp->c_lockowner == current_thread())
                panic("hfs_lock_truncate: cnode 0x%08x locked!", cp);

        if (exclusive)
                lck_rw_lock_exclusive(&cp->c_truncatelock);
        else
                lck_rw_lock_shared(&cp->c_truncatelock);
}

__private_extern__
void
hfs_unlock_truncate(struct cnode *cp)
{
        lck_rw_done(&cp->c_truncatelock);
}