FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_jops.c

     /*
      * Copyright (c) 2004-2006 The DragonFly Project.  All rights reserved.
      * 
      * This code is derived from software contributed to The DragonFly Project
      * by Matthew Dillon <dillon@backplane.com>
      * 
      * 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. Neither the name of The DragonFly Project 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 COPYRIGHT HOLDERS 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
     * COPYRIGHT HOLDERS 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.
     *
     * $DragonFly: src/sys/kern/vfs_jops.c,v 1.36 2007/08/21 17:43:52 dillon Exp $
     */
    /*
     * Each mount point may have zero or more independantly configured journals
     * attached to it.  Each journal is represented by a memory FIFO and worker
     * thread.  Journal events are streamed through the FIFO to the thread,
     * batched up (typically on one-second intervals), and written out by the
     * thread. 
     *
     * Journal vnode ops are executed instead of mnt_vn_norm_ops when one or
     * more journals have been installed on a mount point.  It becomes the
     * responsibility of the journal op to call the underlying normal op as
     * appropriate.
     */
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/buf.h>
    #include <sys/conf.h>
    #include <sys/kernel.h>
    #include <sys/queue.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/mount.h>
    #include <sys/unistd.h>
    #include <sys/vnode.h>
    #include <sys/poll.h>
    #include <sys/mountctl.h>
    #include <sys/journal.h>
    #include <sys/file.h>
    #include <sys/proc.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    
    #include <machine/limits.h>
    
    #include <vm/vm.h>
    #include <vm/vm_object.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pager.h>
    #include <vm/vnode_pager.h>
    
    #include <sys/file2.h>
    #include <sys/thread2.h>
    
    static int journal_attach(struct mount *mp);
    static void journal_detach(struct mount *mp);
    static int journal_install_vfs_journal(struct mount *mp, struct file *fp,
                                const struct mountctl_install_journal *info);
    static int journal_restart_vfs_journal(struct mount *mp, struct file *fp,
                                const struct mountctl_restart_journal *info);
    static int journal_remove_vfs_journal(struct mount *mp,
                                const struct mountctl_remove_journal *info);
    static int journal_restart(struct mount *mp, struct file *fp,
                                struct journal *jo, int flags);
    static int journal_destroy(struct mount *mp, struct journal *jo, int flags);
    static int journal_resync_vfs_journal(struct mount *mp, const void *ctl);
    static int journal_status_vfs_journal(struct mount *mp,
                           const struct mountctl_status_journal *info,
                           struct mountctl_journal_ret_status *rstat,
                           int buflen, int *res);
    
    static void jrecord_undo_file(struct jrecord *jrec, struct vnode *vp,
                                 int jrflags, off_t off, off_t bytes);
    
    static int journal_setattr(struct vop_setattr_args *ap);
    static int journal_write(struct vop_write_args *ap);
   static int journal_fsync(struct vop_fsync_args *ap);
   static int journal_putpages(struct vop_putpages_args *ap);
   static int journal_setacl(struct vop_setacl_args *ap);
   static int journal_setextattr(struct vop_setextattr_args *ap);
   static int journal_ncreate(struct vop_ncreate_args *ap);
   static int journal_nmknod(struct vop_nmknod_args *ap);
   static int journal_nlink(struct vop_nlink_args *ap);
   static int journal_nsymlink(struct vop_nsymlink_args *ap);
   static int journal_nwhiteout(struct vop_nwhiteout_args *ap);
   static int journal_nremove(struct vop_nremove_args *ap);
   static int journal_nmkdir(struct vop_nmkdir_args *ap);
   static int journal_nrmdir(struct vop_nrmdir_args *ap);
   static int journal_nrename(struct vop_nrename_args *ap);
   
   #define JRUNDO_SIZE     0x00000001
   #define JRUNDO_UID      0x00000002
   #define JRUNDO_GID      0x00000004
   #define JRUNDO_FSID     0x00000008
   #define JRUNDO_MODES    0x00000010
   #define JRUNDO_INUM     0x00000020
   #define JRUNDO_ATIME    0x00000040
   #define JRUNDO_MTIME    0x00000080
   #define JRUNDO_CTIME    0x00000100
   #define JRUNDO_GEN      0x00000200
   #define JRUNDO_FLAGS    0x00000400
   #define JRUNDO_UDEV     0x00000800
   #define JRUNDO_NLINK    0x00001000
   #define JRUNDO_FILEDATA 0x00010000
   #define JRUNDO_GETVP    0x00020000
   #define JRUNDO_CONDLINK 0x00040000      /* write file data if link count 1 */
   #define JRUNDO_VATTR    (JRUNDO_SIZE|JRUNDO_UID|JRUNDO_GID|JRUNDO_FSID|\
                            JRUNDO_MODES|JRUNDO_INUM|JRUNDO_ATIME|JRUNDO_MTIME|\
                            JRUNDO_CTIME|JRUNDO_GEN|JRUNDO_FLAGS|JRUNDO_UDEV|\
                            JRUNDO_NLINK)
   #define JRUNDO_ALL      (JRUNDO_VATTR|JRUNDO_FILEDATA)
   
   static struct vop_ops journal_vnode_vops = {
       .vop_default =      vop_journal_operate_ap,
       .vop_mountctl =     journal_mountctl,
       .vop_setattr =      journal_setattr,
       .vop_write =        journal_write,
       .vop_fsync =        journal_fsync,
       .vop_putpages =     journal_putpages,
       .vop_setacl =       journal_setacl,
       .vop_setextattr =   journal_setextattr,
       .vop_ncreate =      journal_ncreate,
       .vop_nmknod =       journal_nmknod,
       .vop_nlink =        journal_nlink,
       .vop_nsymlink =     journal_nsymlink,
       .vop_nwhiteout =    journal_nwhiteout,
       .vop_nremove =      journal_nremove,
       .vop_nmkdir =       journal_nmkdir,
       .vop_nrmdir =       journal_nrmdir,
       .vop_nrename =      journal_nrename
   };
   
   int
   journal_mountctl(struct vop_mountctl_args *ap)
   {
       struct mount *mp;
       int error = 0;
   
       mp = ap->a_head.a_ops->head.vv_mount;
       KKASSERT(mp);
   
       if (mp->mnt_vn_journal_ops == NULL) {
           switch(ap->a_op) {
           case MOUNTCTL_INSTALL_VFS_JOURNAL:
               error = journal_attach(mp);
               if (error == 0 && ap->a_ctllen != sizeof(struct mountctl_install_journal))
                   error = EINVAL;
               if (error == 0 && ap->a_fp == NULL)
                   error = EBADF;
               if (error == 0)
                   error = journal_install_vfs_journal(mp, ap->a_fp, ap->a_ctl);
               if (TAILQ_EMPTY(&mp->mnt_jlist))
                   journal_detach(mp);
               break;
           case MOUNTCTL_RESTART_VFS_JOURNAL:
           case MOUNTCTL_REMOVE_VFS_JOURNAL:
           case MOUNTCTL_RESYNC_VFS_JOURNAL:
           case MOUNTCTL_STATUS_VFS_JOURNAL:
               error = ENOENT;
               break;
           default:
               error = EOPNOTSUPP;
               break;
           }
       } else {
           switch(ap->a_op) {
           case MOUNTCTL_INSTALL_VFS_JOURNAL:
               if (ap->a_ctllen != sizeof(struct mountctl_install_journal))
                   error = EINVAL;
               if (error == 0 && ap->a_fp == NULL)
                   error = EBADF;
               if (error == 0)
                   error = journal_install_vfs_journal(mp, ap->a_fp, ap->a_ctl);
               break;
           case MOUNTCTL_RESTART_VFS_JOURNAL:
               if (ap->a_ctllen != sizeof(struct mountctl_restart_journal))
                   error = EINVAL;
               if (error == 0 && ap->a_fp == NULL)
                   error = EBADF;
               if (error == 0)
                   error = journal_restart_vfs_journal(mp, ap->a_fp, ap->a_ctl);
               break;
           case MOUNTCTL_REMOVE_VFS_JOURNAL:
               if (ap->a_ctllen != sizeof(struct mountctl_remove_journal))
                   error = EINVAL;
               if (error == 0)
                   error = journal_remove_vfs_journal(mp, ap->a_ctl);
               if (TAILQ_EMPTY(&mp->mnt_jlist))
                   journal_detach(mp);
               break;
           case MOUNTCTL_RESYNC_VFS_JOURNAL:
               if (ap->a_ctllen != 0)
                   error = EINVAL;
               error = journal_resync_vfs_journal(mp, ap->a_ctl);
               break;
           case MOUNTCTL_STATUS_VFS_JOURNAL:
               if (ap->a_ctllen != sizeof(struct mountctl_status_journal))
                   error = EINVAL;
               if (error == 0) {
                   error = journal_status_vfs_journal(mp, ap->a_ctl, 
                                           ap->a_buf, ap->a_buflen, ap->a_res);
               }
               break;
           default:
               error = EOPNOTSUPP;
               break;
           }
       }
       return (error);
   }
   
   /*
    * High level mount point setup.  When a 
    */
   static int
   journal_attach(struct mount *mp)
   {
       KKASSERT(mp->mnt_jbitmap == NULL);
       vfs_add_vnodeops(mp, &journal_vnode_vops, &mp->mnt_vn_journal_ops);
       mp->mnt_jbitmap = kmalloc(JREC_STREAMID_JMAX/8, M_JOURNAL, M_WAITOK|M_ZERO);
       mp->mnt_streamid = JREC_STREAMID_JMIN;
       return(0);
   }
   
   static void
   journal_detach(struct mount *mp)
   {
       KKASSERT(mp->mnt_jbitmap != NULL);
       if (mp->mnt_vn_journal_ops)
           vfs_rm_vnodeops(mp, &journal_vnode_vops, &mp->mnt_vn_journal_ops);
       kfree(mp->mnt_jbitmap, M_JOURNAL);
       mp->mnt_jbitmap = NULL;
   }
   
   /*
    * Install a journal on a mount point.  Each journal has an associated worker
    * thread which is responsible for buffering and spooling the data to the
    * target.  A mount point may have multiple journals attached to it.  An
    * initial start record is generated when the journal is associated.
    */
   static int
   journal_install_vfs_journal(struct mount *mp, struct file *fp, 
                               const struct mountctl_install_journal *info)
   {
       struct journal *jo;
       struct jrecord jrec;
       int error = 0;
       int size;
   
       jo = kmalloc(sizeof(struct journal), M_JOURNAL, M_WAITOK|M_ZERO);
       bcopy(info->id, jo->id, sizeof(jo->id));
       jo->flags = info->flags & ~(MC_JOURNAL_WACTIVE | MC_JOURNAL_RACTIVE |
                                   MC_JOURNAL_STOP_REQ);
   
       /*
        * Memory FIFO size, round to nearest power of 2
        */
       if (info->membufsize) {
           if (info->membufsize < 65536)
               size = 65536;
           else if (info->membufsize > 128 * 1024 * 1024)
               size = 128 * 1024 * 1024;
           else
               size = (int)info->membufsize;
       } else {
           size = 1024 * 1024;
       }
       jo->fifo.size = 1;
       while (jo->fifo.size < size)
           jo->fifo.size <<= 1;
   
       /*
        * Other parameters.  If not specified the starting transaction id
        * will be the current date.
        */
       if (info->transid) {
           jo->transid = info->transid;
       } else {
           struct timespec ts;
           getnanotime(&ts);
           jo->transid = ((int64_t)ts.tv_sec << 30) | ts.tv_nsec;
       }
   
       jo->fp = fp;
   
       /*
        * Allocate the memory FIFO
        */
       jo->fifo.mask = jo->fifo.size - 1;
       jo->fifo.membase = kmalloc(jo->fifo.size, M_JFIFO, M_WAITOK|M_ZERO|M_NULLOK);
       if (jo->fifo.membase == NULL)
           error = ENOMEM;
   
       /*
        * Create the worker threads and generate the association record.
        */
       if (error) {
           kfree(jo, M_JOURNAL);
       } else {
           fhold(fp);
           journal_create_threads(jo);
           jrecord_init(jo, &jrec, JREC_STREAMID_DISCONT);
           jrecord_write(&jrec, JTYPE_ASSOCIATE, 0);
           jrecord_done(&jrec, 0);
           TAILQ_INSERT_TAIL(&mp->mnt_jlist, jo, jentry);
       }
       return(error);
   }
   
   /*
    * Restart a journal with a new descriptor.   The existing reader and writer
    * threads are terminated and a new descriptor is associated with the
    * journal.  The FIFO rindex is reset to xindex and the threads are then
    * restarted.
    */
   static int
   journal_restart_vfs_journal(struct mount *mp, struct file *fp,
                              const struct mountctl_restart_journal *info)
   {
       struct journal *jo;
       int error;
   
       TAILQ_FOREACH(jo, &mp->mnt_jlist, jentry) {
           if (bcmp(jo->id, info->id, sizeof(jo->id)) == 0)
               break;
       }
       if (jo)
           error = journal_restart(mp, fp, jo, info->flags);
       else
           error = EINVAL;
       return (error);
   }
   
   static int
   journal_restart(struct mount *mp, struct file *fp, 
                   struct journal *jo, int flags)
   {
       /*
        * XXX lock the jo
        */
   
   #if 0
       /*
        * Record the fact that we are doing a restart in the journal.
        * XXX it isn't safe to do this if the journal is being restarted
        * because it was locked up and the writer thread has already exited.
        */
       jrecord_init(jo, &jrec, JREC_STREAMID_RESTART);
       jrecord_write(&jrec, JTYPE_DISASSOCIATE, 0);
       jrecord_done(&jrec, 0);
   #endif
   
       /*
        * Stop the reader and writer threads and clean up the current 
        * descriptor.
        */
       kprintf("RESTART WITH FP %p KILLING %p\n", fp, jo->fp);
       journal_destroy_threads(jo, flags);
   
       if (jo->fp)
           fdrop(jo->fp);
   
       /*
        * Associate the new descriptor, reset the FIFO index, and recreate
        * the threads.
        */
       fhold(fp);
       jo->fp = fp;
       jo->fifo.rindex = jo->fifo.xindex;
       journal_create_threads(jo);
   
       return(0);
   }
   
   /*
    * Disassociate a journal from a mount point and terminate its worker thread.
    * A final termination record is written out before the file pointer is
    * dropped.
    */
   static int
   journal_remove_vfs_journal(struct mount *mp, 
                              const struct mountctl_remove_journal *info)
   {
       struct journal *jo;
       int error;
   
       TAILQ_FOREACH(jo, &mp->mnt_jlist, jentry) {
           if (bcmp(jo->id, info->id, sizeof(jo->id)) == 0)
               break;
       }
       if (jo)
           error = journal_destroy(mp, jo, info->flags);
       else
           error = EINVAL;
       return (error);
   }
   
   /*
    * Remove all journals associated with a mount point.  Usually called
    * by the umount code.
    */
   void
   journal_remove_all_journals(struct mount *mp, int flags)
   {
       struct journal *jo;
   
       while ((jo = TAILQ_FIRST(&mp->mnt_jlist)) != NULL) {
           journal_destroy(mp, jo, flags);
       }
   }
   
   static int
   journal_destroy(struct mount *mp, struct journal *jo, int flags)
   {
       struct jrecord jrec;
   
       TAILQ_REMOVE(&mp->mnt_jlist, jo, jentry);
   
       jrecord_init(jo, &jrec, JREC_STREAMID_DISCONT);
       jrecord_write(&jrec, JTYPE_DISASSOCIATE, 0);
       jrecord_done(&jrec, 0);
   
       journal_destroy_threads(jo, flags);
   
       if (jo->fp)
           fdrop(jo->fp);
       if (jo->fifo.membase)
           kfree(jo->fifo.membase, M_JFIFO);
       kfree(jo, M_JOURNAL);
   
       return(0);
   }
   
   static int
   journal_resync_vfs_journal(struct mount *mp, const void *ctl)
   {
       return(EINVAL);
   }
   
   static int
   journal_status_vfs_journal(struct mount *mp, 
                          const struct mountctl_status_journal *info,
                          struct mountctl_journal_ret_status *rstat,
                          int buflen, int *res)
   {
       struct journal *jo;
       int error = 0;
       int index;
   
       index = 0;
       *res = 0;
       TAILQ_FOREACH(jo, &mp->mnt_jlist, jentry) {
           if (info->index == MC_JOURNAL_INDEX_ID) {
               if (bcmp(jo->id, info->id, sizeof(jo->id)) != 0)
                   continue;
           } else if (info->index >= 0) {
               if (info->index < index)
                   continue;
           } else if (info->index != MC_JOURNAL_INDEX_ALL) {
               continue;
           }
           if (buflen < sizeof(*rstat)) {
               if (*res)
                   rstat[-1].flags |= MC_JOURNAL_STATUS_MORETOCOME;
               else
                   error = EINVAL;
               break;
           }
           bzero(rstat, sizeof(*rstat));
           rstat->recsize = sizeof(*rstat);
           bcopy(jo->id, rstat->id, sizeof(jo->id));
           rstat->index = index;
           rstat->membufsize = jo->fifo.size;
           rstat->membufused = jo->fifo.windex - jo->fifo.xindex;
           rstat->membufunacked = jo->fifo.rindex - jo->fifo.xindex;
           rstat->bytessent = jo->total_acked;
           rstat->fifostalls = jo->fifostalls;
           ++rstat;
           ++index;
           *res += sizeof(*rstat);
           buflen -= sizeof(*rstat);
       }
       return(error);
   }
   
   /************************************************************************
    *                      PARALLEL TRANSACTION SUPPORT ROUTINES           *
    ************************************************************************
    *
    * JRECLIST_*() - routines which create and iterate over jrecord structures,
    *                because a mount point may have multiple attached journals.
    */
   
   /*
    * Initialize the passed jrecord_list and create a jrecord for each 
    * journal we need to write to.  Unnecessary mallocs are avoided by
    * using the passed jrecord structure as the first jrecord in the list.
    * A starting transaction is pushed for each jrecord.
    *
    * Returns non-zero if any of the journals require undo records.
    */
   static
   int
   jreclist_init(struct mount *mp, struct jrecord_list *jreclist, 
                 struct jrecord *jreccache, int16_t rectype)
   {
       struct journal *jo;
       struct jrecord *jrec;
       int wantrev;
       int count;
       int16_t streamid;
   
       TAILQ_INIT(&jreclist->list);
   
       /*
        * Select the stream ID to use for the transaction.  We must select
        * a stream ID that is not currently in use by some other parallel
        * transaction.  
        *
        * Don't bother calculating the next streamid when reassigning
        * mnt_streamid, since parallel transactions are fairly rare.  This
        * also allows someone observing the raw records to clearly see
        * when parallel transactions occur.
        */
       streamid = mp->mnt_streamid;
       count = 0;
       while (mp->mnt_jbitmap[streamid >> 3] & (1 << (streamid & 7))) {
           if (++streamid == JREC_STREAMID_JMAX)
                   streamid = JREC_STREAMID_JMIN;
           if (++count == JREC_STREAMID_JMAX - JREC_STREAMID_JMIN) {
                   kprintf("jreclist_init: all streamid's in use! sleeping\n");
                   tsleep(jreclist, 0, "jsidfl", hz * 10);
                   count = 0;
           }
       }
       mp->mnt_jbitmap[streamid >> 3] |= 1 << (streamid & 7);
       mp->mnt_streamid = streamid;
       jreclist->streamid = streamid;
   
       /*
        * Now initialize a stream on each journal.
        */
       count = 0;
       wantrev = 0;
       TAILQ_FOREACH(jo, &mp->mnt_jlist, jentry) {
           if (count == 0)
               jrec = jreccache;
           else
               jrec = kmalloc(sizeof(*jrec), M_JOURNAL, M_WAITOK);
           jrecord_init(jo, jrec, streamid);
           jrec->user_save = jrecord_push(jrec, rectype);
           TAILQ_INSERT_TAIL(&jreclist->list, jrec, user_entry);
           if (jo->flags & MC_JOURNAL_WANT_REVERSABLE)
               wantrev = 1;
           ++count;
       }
       return(wantrev);
   }
   
   /*
    * Terminate the journaled transactions started by jreclist_init().  If
    * an error occured, the transaction records will be aborted.
    */
   static
   void
   jreclist_done(struct mount *mp, struct jrecord_list *jreclist, int error)
   {
       struct jrecord *jrec;
       int count;
   
       /*
        * Cleanup the jrecord state on each journal.
        */
       TAILQ_FOREACH(jrec, &jreclist->list, user_entry) {
           jrecord_pop(jrec, jrec->user_save);
           jrecord_done(jrec, error);
       }
   
       /*
        * Free allocated jrec's (the first is always supplied)
        */
       count = 0;
       while ((jrec = TAILQ_FIRST(&jreclist->list)) != NULL) {
           TAILQ_REMOVE(&jreclist->list, jrec, user_entry);
           if (count)
               kfree(jrec, M_JOURNAL);
           ++count;
       }
   
       /*
        * Clear the streamid so it can be reused.
        */
       mp->mnt_jbitmap[jreclist->streamid >> 3] &= ~(1 << (jreclist->streamid & 7));
   }
   
   /*
    * This procedure writes out UNDO records for available reversable
    * journals.
    *
    * XXX could use improvement.  There is no need to re-read the file
    * for each journal.
    */
   static
   void
   jreclist_undo_file(struct jrecord_list *jreclist, struct vnode *vp, 
                      int jrflags, off_t off, off_t bytes)
   {
       struct jrecord *jrec;
       int error;
   
       error = 0;
       if (jrflags & JRUNDO_GETVP)
           error = vget(vp, LK_SHARED);
       if (error == 0) {
           TAILQ_FOREACH(jrec, &jreclist->list, user_entry) {
               if (jrec->jo->flags & MC_JOURNAL_WANT_REVERSABLE) {
                   jrecord_undo_file(jrec, vp, jrflags, off, bytes);
               }
           }
       }
       if (error == 0 && jrflags & JRUNDO_GETVP)
           vput(vp);
   }
   
   /************************************************************************
    *                      LOW LEVEL UNDO SUPPORT ROUTINE                  *
    ************************************************************************
    *
    * This function is used to support UNDO records.  It will generate an
    * appropriate record with the requested portion of the file data.  Note
    * that file data is only recorded if JRUNDO_FILEDATA is passed.  If bytes
    * is -1, it will be set to the size of the file.
    */
   static void
   jrecord_undo_file(struct jrecord *jrec, struct vnode *vp, int jrflags, 
                     off_t off, off_t bytes)
   {
       struct vattr attr;
       void *save1; /* warning, save pointers do not always remain valid */
       void *save2;
       int error;
   
       /*
        * Setup.  Start the UNDO record, obtain a shared lock on the vnode,
        * and retrieve attribute info.
        */
       save1 = jrecord_push(jrec, JTYPE_UNDO);
       error = VOP_GETATTR(vp, &attr);
       if (error)
           goto done;
   
       /*
        * Generate UNDO records as requested.
        */
       if (jrflags & JRUNDO_VATTR) {
           save2 = jrecord_push(jrec, JTYPE_VATTR);
           jrecord_leaf(jrec, JLEAF_VTYPE, &attr.va_type, sizeof(attr.va_type));
           if ((jrflags & JRUNDO_NLINK) && attr.va_nlink != VNOVAL)
               jrecord_leaf(jrec, JLEAF_NLINK, &attr.va_nlink, sizeof(attr.va_nlink));
           if ((jrflags & JRUNDO_SIZE) && attr.va_size != VNOVAL)
               jrecord_leaf(jrec, JLEAF_SIZE, &attr.va_size, sizeof(attr.va_size));
           if ((jrflags & JRUNDO_UID) && attr.va_uid != VNOVAL)
               jrecord_leaf(jrec, JLEAF_UID, &attr.va_uid, sizeof(attr.va_uid));
           if ((jrflags & JRUNDO_GID) && attr.va_gid != VNOVAL)
               jrecord_leaf(jrec, JLEAF_GID, &attr.va_gid, sizeof(attr.va_gid));
           if ((jrflags & JRUNDO_FSID) && attr.va_fsid != VNOVAL)
               jrecord_leaf(jrec, JLEAF_FSID, &attr.va_fsid, sizeof(attr.va_fsid));
           if ((jrflags & JRUNDO_MODES) && attr.va_mode != (mode_t)VNOVAL)
               jrecord_leaf(jrec, JLEAF_MODES, &attr.va_mode, sizeof(attr.va_mode));
           if ((jrflags & JRUNDO_INUM) && attr.va_fileid != VNOVAL)
               jrecord_leaf(jrec, JLEAF_INUM, &attr.va_fileid, sizeof(attr.va_fileid));
           if ((jrflags & JRUNDO_ATIME) && attr.va_atime.tv_sec != VNOVAL)
               jrecord_leaf(jrec, JLEAF_ATIME, &attr.va_atime, sizeof(attr.va_atime));
           if ((jrflags & JRUNDO_MTIME) && attr.va_mtime.tv_sec != VNOVAL)
               jrecord_leaf(jrec, JLEAF_MTIME, &attr.va_mtime, sizeof(attr.va_mtime));
           if ((jrflags & JRUNDO_CTIME) && attr.va_ctime.tv_sec != VNOVAL)
               jrecord_leaf(jrec, JLEAF_CTIME, &attr.va_ctime, sizeof(attr.va_ctime));
           if ((jrflags & JRUNDO_GEN) && attr.va_gen != VNOVAL)
               jrecord_leaf(jrec, JLEAF_GEN, &attr.va_gen, sizeof(attr.va_gen));
           if ((jrflags & JRUNDO_FLAGS) && attr.va_flags != VNOVAL)
               jrecord_leaf(jrec, JLEAF_FLAGS, &attr.va_flags, sizeof(attr.va_flags));
           if ((jrflags & JRUNDO_UDEV) && attr.va_rmajor != VNOVAL) {
               udev_t rdev = makeudev(attr.va_rmajor, attr.va_rminor);
               jrecord_leaf(jrec, JLEAF_UDEV, &rdev, sizeof(rdev));
               jrecord_leaf(jrec, JLEAF_UMAJOR, &attr.va_rmajor, sizeof(attr.va_rmajor));
               jrecord_leaf(jrec, JLEAF_UMINOR, &attr.va_rminor, sizeof(attr.va_rminor));
           }
           jrecord_pop(jrec, save2);
       }
   
       /*
        * Output the file data being overwritten by reading the file and
        * writing it out to the journal prior to the write operation.  We
        * do not need to write out data past the current file EOF.
        *
        * XXX support JRUNDO_CONDLINK - do not write out file data for files
        * with a link count > 1.  The undo code needs to locate the inode and
        * regenerate the hardlink.
        */
       if ((jrflags & JRUNDO_FILEDATA) && attr.va_type == VREG) {
           if (attr.va_size != VNOVAL) {
               if (bytes == -1)
                   bytes = attr.va_size - off;
               if (off + bytes > attr.va_size)
                   bytes = attr.va_size - off;
               if (bytes > 0)
                   jrecord_file_data(jrec, vp, off, bytes);
           } else {
               error = EINVAL;
           }
       }
       if ((jrflags & JRUNDO_FILEDATA) && attr.va_type == VLNK) {
           struct iovec aiov;
           struct uio auio;
           char *buf;
   
           buf = kmalloc(PATH_MAX, M_JOURNAL, M_WAITOK);
           aiov.iov_base = buf;
           aiov.iov_len = PATH_MAX;
           auio.uio_iov = &aiov;
           auio.uio_iovcnt = 1;
           auio.uio_offset = 0;
           auio.uio_rw = UIO_READ;
           auio.uio_segflg = UIO_SYSSPACE;
           auio.uio_td = curthread;
           auio.uio_resid = PATH_MAX;
           error = VOP_READLINK(vp, &auio, proc0.p_ucred);
           if (error == 0) {
                   jrecord_leaf(jrec, JLEAF_SYMLINKDATA, buf, 
                                   PATH_MAX - auio.uio_resid);
           }
           kfree(buf, M_JOURNAL);
       }
   done:
       if (error)
           jrecord_leaf(jrec, JLEAF_ERROR, &error, sizeof(error));
       jrecord_pop(jrec, save1);
   }
   
   /************************************************************************
    *                      JOURNAL VNOPS                                   *
    ************************************************************************
    *
    * These are function shims replacing the normal filesystem ops.  We become
    * responsible for calling the underlying filesystem ops.  We have the choice
    * of executing the underlying op first and then generating the journal entry,
    * or starting the journal entry, executing the underlying op, and then
    * either completing or aborting it.  
    *
    * The journal is supposed to be a high-level entity, which generally means
    * identifying files by name rather then by inode.  Supplying both allows
    * the journal to be used both for inode-number-compatible 'mirrors' and
    * for simple filesystem replication.
    *
    * Writes are particularly difficult to deal with because a single write may
    * represent a hundred megabyte buffer or more, and both writes and truncations
    * require the 'old' data to be written out as well as the new data if the
    * log is reversable.  Other issues:
    *
    * - How to deal with operations on unlinked files (no path available),
    *   but which may still be filesystem visible due to hard links.
    *
    * - How to deal with modifications made via a memory map.
    *
    * - Future cache coherency support will require cache coherency API calls
    *   both prior to and after the call to the underlying VFS.
    *
    * ALSO NOTE: We do not have to shim compatibility VOPs like MKDIR which have
    * new VFS equivalents (NMKDIR).
    */
   
   /*
    * Journal vop_setattr { a_vp, a_vap, a_cred }
    */
   static
   int
   journal_setattr(struct vop_setattr_args *ap)
   {
       struct jrecord_list jreclist;
       struct jrecord jreccache;
       struct jrecord *jrec;
       struct mount *mp;
       void *save;
       int error;
   
       mp = ap->a_head.a_ops->head.vv_mount;
       if (jreclist_init(mp, &jreclist, &jreccache, JTYPE_SETATTR)) {
           jreclist_undo_file(&jreclist, ap->a_vp, JRUNDO_VATTR, 0, 0);
       }
       error = vop_journal_operate_ap(&ap->a_head);
       if (error == 0) {
           TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
               jrecord_write_cred(jrec, curthread, ap->a_cred);
               jrecord_write_vnode_ref(jrec, ap->a_vp);
               save = jrecord_push(jrec, JTYPE_REDO);
               jrecord_write_vattr(jrec, ap->a_vap);
               jrecord_pop(jrec, save);
           }
       }
       jreclist_done(mp, &jreclist, error);
       return (error);
   }
   
   /*
    * Journal vop_write { a_vp, a_uio, a_ioflag, a_cred }
    */
   static
   int
   journal_write(struct vop_write_args *ap)
   {
       struct jrecord_list jreclist;
       struct jrecord jreccache;
       struct jrecord *jrec;
       struct mount *mp;
       struct uio uio_copy;
       struct iovec uio_one_iovec;
       void *save;
       int error;
   
       /*
        * Special synchronizing writes for VM backing store do not supply any
        * real data
        */
       if (ap->a_uio->uio_segflg == UIO_NOCOPY) {
               error = vop_journal_operate_ap(&ap->a_head);
               return (error);
       }
   
       /*
        * This is really nasty.  UIO's don't retain sufficient information to
        * be reusable once they've gone through the VOP chain.  The iovecs get
        * cleared, so we have to copy the UIO.
        *
        * XXX fix the UIO code to not destroy iov's during a scan so we can
        *     reuse the uio over and over again.
        *
        * XXX UNDO code needs to journal the old data prior to the write.
        */
       uio_copy = *ap->a_uio;
       if (uio_copy.uio_iovcnt == 1) {
           uio_one_iovec = ap->a_uio->uio_iov[0];
           uio_copy.uio_iov = &uio_one_iovec;
       } else {
           uio_copy.uio_iov = kmalloc(uio_copy.uio_iovcnt * sizeof(struct iovec),
                                       M_JOURNAL, M_WAITOK);
           bcopy(ap->a_uio->uio_iov, uio_copy.uio_iov, 
                   uio_copy.uio_iovcnt * sizeof(struct iovec));
       }
   
       /*
        * Write out undo data.  Note that uio_offset is incorrect if
        * IO_APPEND is set, but fortunately we have no undo file data to
        * write out in that case.
        */
       mp = ap->a_head.a_ops->head.vv_mount;
       if (jreclist_init(mp, &jreclist, &jreccache, JTYPE_WRITE)) {
           if (ap->a_ioflag & IO_APPEND) {
               jreclist_undo_file(&jreclist, ap->a_vp, JRUNDO_SIZE|JRUNDO_MTIME, 0, 0);
           } else {
               jreclist_undo_file(&jreclist, ap->a_vp, 
                                  JRUNDO_FILEDATA|JRUNDO_SIZE|JRUNDO_MTIME, 
                                  uio_copy.uio_offset, uio_copy.uio_resid);
           }
       }
       error = vop_journal_operate_ap(&ap->a_head);
   
       /*
        * XXX bad hack to figure out the offset for O_APPEND writes (note: 
        * uio field state after the VFS operation).
        */
       uio_copy.uio_offset = ap->a_uio->uio_offset - 
                             (uio_copy.uio_resid - ap->a_uio->uio_resid);
   
       /*
        * Output the write data to the journal.
        */
       if (error == 0) {
           TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
               jrecord_write_cred(jrec, NULL, ap->a_cred);
               jrecord_write_vnode_ref(jrec, ap->a_vp);
               save = jrecord_push(jrec, JTYPE_REDO);
               jrecord_write_uio(jrec, JLEAF_FILEDATA, &uio_copy);
               jrecord_pop(jrec, save);
           }
       }
       jreclist_done(mp, &jreclist, error);
   
       if (uio_copy.uio_iov != &uio_one_iovec)
           kfree(uio_copy.uio_iov, M_JOURNAL);
       return (error);
   }
   
   /*
    * Journal vop_fsync { a_vp, a_waitfor }
    */
   static
   int
   journal_fsync(struct vop_fsync_args *ap)
   {
   #if 0
       struct mount *mp;
       struct journal *jo;
   #endif
       int error;
   
       error = vop_journal_operate_ap(&ap->a_head);
   #if 0
       mp = ap->a_head.a_ops->head.vv_mount;
       if (error == 0) {
           TAILQ_FOREACH(jo, &mp->mnt_jlist, jentry) {
               /* XXX synchronize pending journal records */
           }
       }
   #endif
       return (error);
   }
   
   /*
    * Journal vop_putpages { a_vp, a_m, a_count, a_sync, a_rtvals, a_offset }
    *
    * note: a_count is in bytes.
    */
   static
   int
   journal_putpages(struct vop_putpages_args *ap)
   {
       struct jrecord_list jreclist;
       struct jrecord jreccache;
       struct jrecord *jrec;
       struct mount *mp;
       void *save;
       int error;
   
       mp = ap->a_head.a_ops->head.vv_mount;
       if (jreclist_init(mp, &jreclist, &jreccache, JTYPE_PUTPAGES) && 
           ap->a_count > 0
       ) {
           jreclist_undo_file(&jreclist, ap->a_vp, 
                              JRUNDO_FILEDATA|JRUNDO_SIZE|JRUNDO_MTIME, 
                              ap->a_offset, btoc(ap->a_count));
       }
       error = vop_journal_operate_ap(&ap->a_head);
       if (error == 0 && ap->a_count > 0) {
           TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
               jrecord_write_vnode_ref(jrec, ap->a_vp);
               save = jrecord_push(jrec, JTYPE_REDO);
               jrecord_write_pagelist(jrec, JLEAF_FILEDATA, ap->a_m, ap->a_rtvals, 
                                      btoc(ap->a_count), ap->a_offset);
               jrecord_pop(jrec, save);
           }
       }
       jreclist_done(mp, &jreclist, error);
       return (error);
   }
   
   /*
    * Journal vop_setacl { a_vp, a_type, a_aclp, a_cred }
    */
   static
   int
   journal_setacl(struct vop_setacl_args *ap)
   {
       struct jrecord_list jreclist;
       struct jrecord jreccache;
       struct jrecord *jrec;
       struct mount *mp;
       int error;
   
       mp = ap->a_head.a_ops->head.vv_mount;
       jreclist_init(mp, &jreclist, &jreccache, JTYPE_SETACL);
       error = vop_journal_operate_ap(&ap->a_head);
       if (error == 0) {
           TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
   #if 0
               if ((jo->flags & MC_JOURNAL_WANT_REVERSABLE))
                   jrecord_undo_file(jrec, ap->a_vp, JRUNDO_XXX, 0, 0);
  #endif
              jrecord_write_cred(jrec, curthread, ap->a_cred);
              jrecord_write_vnode_ref(jrec, ap->a_vp);
  #if 0
              save = jrecord_push(jrec, JTYPE_REDO);
              /* XXX type, aclp */
              jrecord_pop(jrec, save);
  #endif
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_setextattr { a_vp, a_name, a_uio, a_cred }
   */
  static
  int
  journal_setextattr(struct vop_setextattr_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      void *save;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_SETEXTATTR);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
  #if 0
              if ((jo->flags & MC_JOURNAL_WANT_REVERSABLE))
                  jrecord_undo_file(jrec, ap->a_vp, JRUNDO_XXX, 0, 0);
  #endif
              jrecord_write_cred(jrec, curthread, ap->a_cred);
              jrecord_write_vnode_ref(jrec, ap->a_vp);
              jrecord_leaf(jrec, JLEAF_ATTRNAME, ap->a_attrname,
                          strlen(ap->a_attrname));
              save = jrecord_push(jrec, JTYPE_REDO);
              jrecord_write_uio(jrec, JLEAF_FILEDATA, ap->a_uio);
              jrecord_pop(jrec, save);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_ncreate { a_nch, a_vpp, a_cred, a_vap }
   */
  static
  int
  journal_ncreate(struct vop_ncreate_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      void *save;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_CREATE);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
              if (*ap->a_vpp)
                  jrecord_write_vnode_ref(jrec, *ap->a_vpp);
              save = jrecord_push(jrec, JTYPE_REDO);
              jrecord_write_vattr(jrec, ap->a_vap);
              jrecord_pop(jrec, save);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nmknod { a_nch, a_vpp, a_cred, a_vap }
   */
  static
  int
  journal_nmknod(struct vop_nmknod_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      void *save;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_MKNOD);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
              save = jrecord_push(jrec, JTYPE_REDO);
              jrecord_write_vattr(jrec, ap->a_vap);
              jrecord_pop(jrec, save);
              if (*ap->a_vpp)
                  jrecord_write_vnode_ref(jrec, *ap->a_vpp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nlink { a_nch, a_vp, a_cred }
   */
  static
  int
  journal_nlink(struct vop_nlink_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      void *save;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_LINK);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
              /* XXX PATH to VP and inode number */
              /* XXX this call may not record the correct path when
               * multiple paths are available */
              save = jrecord_push(jrec, JTYPE_REDO);
              jrecord_write_vnode_link(jrec, ap->a_vp, ap->a_nch->ncp);
              jrecord_pop(jrec, save);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_symlink { a_nch, a_vpp, a_cred, a_vap, a_target }
   */
  static
  int
  journal_nsymlink(struct vop_nsymlink_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      void *save;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_SYMLINK);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
              save = jrecord_push(jrec, JTYPE_REDO);
              jrecord_leaf(jrec, JLEAF_SYMLINKDATA,
                          ap->a_target, strlen(ap->a_target));
              jrecord_pop(jrec, save);
              if (*ap->a_vpp)
                  jrecord_write_vnode_ref(jrec, *ap->a_vpp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nwhiteout { a_nch, a_cred, a_flags }
   */
  static
  int
  journal_nwhiteout(struct vop_nwhiteout_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_WHITEOUT);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nremove { a_nch, a_cred }
   */
  static
  int
  journal_nremove(struct vop_nremove_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      if (jreclist_init(mp, &jreclist, &jreccache, JTYPE_REMOVE) &&
          ap->a_nch->ncp->nc_vp
      ) {
          jreclist_undo_file(&jreclist, ap->a_nch->ncp->nc_vp, 
                             JRUNDO_ALL|JRUNDO_GETVP|JRUNDO_CONDLINK, 0, -1);
      }
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nmkdir { a_nch, a_vpp, a_cred, a_vap }
   */
  static
  int
  journal_nmkdir(struct vop_nmkdir_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      jreclist_init(mp, &jreclist, &jreccache, JTYPE_MKDIR);
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
  #if 0
              if (jo->flags & MC_JOURNAL_WANT_AUDIT) {
                  jrecord_write_audit(jrec);
              }
  #endif
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_vattr(jrec, ap->a_vap);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
              if (*ap->a_vpp)
                  jrecord_write_vnode_ref(jrec, *ap->a_vpp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nrmdir { a_nch, a_cred }
   */
  static
  int
  journal_nrmdir(struct vop_nrmdir_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      if (jreclist_init(mp, &jreclist, &jreccache, JTYPE_RMDIR)) {
          jreclist_undo_file(&jreclist, ap->a_nch->ncp->nc_vp,
                             JRUNDO_VATTR|JRUNDO_GETVP, 0, 0);
      }
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_nch->ncp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  
  /*
   * Journal vop_nrename { a_fnch, a_tnch, a_cred }
   */
  static
  int
  journal_nrename(struct vop_nrename_args *ap)
  {
      struct jrecord_list jreclist;
      struct jrecord jreccache;
      struct jrecord *jrec;
      struct mount *mp;
      int error;
  
      mp = ap->a_head.a_ops->head.vv_mount;
      if (jreclist_init(mp, &jreclist, &jreccache, JTYPE_RENAME) &&
          ap->a_tnch->ncp->nc_vp
      ) {
          jreclist_undo_file(&jreclist, ap->a_tnch->ncp->nc_vp, 
                             JRUNDO_ALL|JRUNDO_GETVP|JRUNDO_CONDLINK, 0, -1);
      }
      error = vop_journal_operate_ap(&ap->a_head);
      if (error == 0) {
          TAILQ_FOREACH(jrec, &jreclist.list, user_entry) {
              jrecord_write_cred(jrec, NULL, ap->a_cred);
              jrecord_write_path(jrec, JLEAF_PATH1, ap->a_fnch->ncp);
              jrecord_write_path(jrec, JLEAF_PATH2, ap->a_tnch->ncp);
          }
      }
      jreclist_done(mp, &jreclist, error);
      return (error);
  }
  

Cache object: 2cbdedb4252a6f10a1d19d1192a9e870