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FreeBSD/Linux Kernel Cross Reference
sys/ufs/ffs/ffs_softdep.c

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    1 /*
    2  * Copyright 1998, 2000 Marshall Kirk McKusick. All Rights Reserved.
    3  *
    4  * The soft updates code is derived from the appendix of a University
    5  * of Michigan technical report (Gregory R. Ganger and Yale N. Patt,
    6  * "Soft Updates: A Solution to the Metadata Update Problem in File
    7  * Systems", CSE-TR-254-95, August 1995).
    8  *
    9  * Further information about soft updates can be obtained from:
   10  *
   11  *      Marshall Kirk McKusick          http://www.mckusick.com/softdep/
   12  *      1614 Oxford Street              mckusick@mckusick.com
   13  *      Berkeley, CA 94709-1608         +1-510-843-9542
   14  *      USA
   15  *
   16  * Redistribution and use in source and binary forms, with or without
   17  * modification, are permitted provided that the following conditions
   18  * are met:
   19  *
   20  * 1. Redistributions of source code must retain the above copyright
   21  *    notice, this list of conditions and the following disclaimer.
   22  * 2. Redistributions in binary form must reproduce the above copyright
   23  *    notice, this list of conditions and the following disclaimer in the
   24  *    documentation and/or other materials provided with the distribution.
   25  *
   26  * THIS SOFTWARE IS PROVIDED BY MARSHALL KIRK MCKUSICK ``AS IS'' AND ANY
   27  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   28  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   29  * DISCLAIMED.  IN NO EVENT SHALL MARSHALL KIRK MCKUSICK BE LIABLE FOR
   30  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   36  * SUCH DAMAGE.
   37  *
   38  *      from: @(#)ffs_softdep.c 9.59 (McKusick) 6/21/00
   39  * $FreeBSD: src/sys/ufs/ffs/ffs_softdep.c,v 1.57.2.16 2005/09/20 22:37:54 tegge Exp $
   40  */
   41 
   42 /*
   43  * For now we want the safety net that the DIAGNOSTIC and DEBUG flags provide.
   44  */
   45 #ifndef DIAGNOSTIC
   46 #define DIAGNOSTIC
   47 #endif
   48 #ifndef DEBUG
   49 #define DEBUG
   50 #endif
   51 
   52 #include <sys/param.h>
   53 #include <sys/kernel.h>
   54 #include <sys/systm.h>
   55 #include <sys/buf.h>
   56 #include <sys/malloc.h>
   57 #include <sys/mount.h>
   58 #include <sys/proc.h>
   59 #include <sys/syslog.h>
   60 #include <sys/vnode.h>
   61 #include <sys/conf.h>
   62 #include <ufs/ufs/dir.h>
   63 #include <ufs/ufs/quota.h>
   64 #include <ufs/ufs/inode.h>
   65 #include <ufs/ufs/ufsmount.h>
   66 #include <ufs/ffs/fs.h>
   67 #include <ufs/ffs/softdep.h>
   68 #include <ufs/ffs/ffs_extern.h>
   69 #include <ufs/ufs/ufs_extern.h>
   70 
   71 /*
   72  * These definitions need to be adapted to the system to which
   73  * this file is being ported.
   74  */
   75 /*
   76  * malloc types defined for the softdep system.
   77  */
   78 MALLOC_DEFINE(M_PAGEDEP, "pagedep","File page dependencies");
   79 MALLOC_DEFINE(M_INODEDEP, "inodedep","Inode dependencies");
   80 MALLOC_DEFINE(M_NEWBLK, "newblk","New block allocation");
   81 MALLOC_DEFINE(M_BMSAFEMAP, "bmsafemap","Block or frag allocated from cyl group map");
   82 MALLOC_DEFINE(M_ALLOCDIRECT, "allocdirect","Block or frag dependency for an inode");
   83 MALLOC_DEFINE(M_INDIRDEP, "indirdep","Indirect block dependencies");
   84 MALLOC_DEFINE(M_ALLOCINDIR, "allocindir","Block dependency for an indirect block");
   85 MALLOC_DEFINE(M_FREEFRAG, "freefrag","Previously used frag for an inode");
   86 MALLOC_DEFINE(M_FREEBLKS, "freeblks","Blocks freed from an inode");
   87 MALLOC_DEFINE(M_FREEFILE, "freefile","Inode deallocated");
   88 MALLOC_DEFINE(M_DIRADD, "diradd","New directory entry");
   89 MALLOC_DEFINE(M_MKDIR, "mkdir","New directory");
   90 MALLOC_DEFINE(M_DIRREM, "dirrem","Directory entry deleted");
   91 
   92 #define M_SOFTDEP_FLAGS         (M_WAITOK | M_USE_RESERVE)
   93 
   94 #define D_PAGEDEP       0
   95 #define D_INODEDEP      1
   96 #define D_NEWBLK        2
   97 #define D_BMSAFEMAP     3
   98 #define D_ALLOCDIRECT   4
   99 #define D_INDIRDEP      5
  100 #define D_ALLOCINDIR    6
  101 #define D_FREEFRAG      7
  102 #define D_FREEBLKS      8
  103 #define D_FREEFILE      9
  104 #define D_DIRADD        10
  105 #define D_MKDIR         11
  106 #define D_DIRREM        12
  107 #define D_LAST          D_DIRREM
  108 
  109 /* 
  110  * translate from workitem type to memory type
  111  * MUST match the defines above, such that memtype[D_XXX] == M_XXX
  112  */
  113 static struct malloc_type *memtype[] = {
  114         M_PAGEDEP,
  115         M_INODEDEP,
  116         M_NEWBLK,
  117         M_BMSAFEMAP,
  118         M_ALLOCDIRECT,
  119         M_INDIRDEP,
  120         M_ALLOCINDIR,
  121         M_FREEFRAG,
  122         M_FREEBLKS,
  123         M_FREEFILE,
  124         M_DIRADD,
  125         M_MKDIR,
  126         M_DIRREM
  127 };
  128 
  129 #define DtoM(type) (memtype[type])
  130 
  131 /*
  132  * Names of malloc types.
  133  */
  134 #define TYPENAME(type)  \
  135         ((unsigned)(type) < D_LAST ? memtype[type]->ks_shortdesc : "???")
  136 #define CURPROC curproc
  137 /*
  138  * End system adaptaion definitions.
  139  */
  140 
  141 /*
  142  * Internal function prototypes.
  143  */
  144 static  void softdep_error __P((char *, int));
  145 static  void drain_output __P((struct vnode *, int));
  146 static  int getdirtybuf __P((struct buf **, int));
  147 static  void clear_remove __P((struct proc *));
  148 static  void clear_inodedeps __P((struct proc *));
  149 static  int flush_pagedep_deps __P((struct vnode *, struct mount *,
  150             struct diraddhd *));
  151 static  int flush_inodedep_deps __P((struct fs *, ino_t));
  152 static  int handle_written_filepage __P((struct pagedep *, struct buf *));
  153 static  void diradd_inode_written __P((struct diradd *, struct inodedep *));
  154 static  int handle_written_inodeblock __P((struct inodedep *, struct buf *));
  155 static  void handle_allocdirect_partdone __P((struct allocdirect *));
  156 static  void handle_allocindir_partdone __P((struct allocindir *));
  157 static  void initiate_write_filepage __P((struct pagedep *, struct buf *));
  158 static  void handle_written_mkdir __P((struct mkdir *, int));
  159 static  void initiate_write_inodeblock __P((struct inodedep *, struct buf *));
  160 static  void handle_workitem_freefile __P((struct freefile *));
  161 static  void handle_workitem_remove __P((struct dirrem *));
  162 static  struct dirrem *newdirrem __P((struct buf *, struct inode *,
  163             struct inode *, int, struct dirrem **));
  164 static  void free_diradd __P((struct diradd *));
  165 static  void free_allocindir __P((struct allocindir *, struct inodedep *));
  166 static  int indir_trunc __P((struct inode *, ufs_daddr_t, int, ufs_lbn_t,
  167             long *));
  168 static  void deallocate_dependencies __P((struct buf *, struct inodedep *));
  169 static  void free_allocdirect __P((struct allocdirectlst *,
  170             struct allocdirect *, int));
  171 static  int check_inode_unwritten __P((struct inodedep *));
  172 static  int free_inodedep __P((struct inodedep *));
  173 static  void handle_workitem_freeblocks __P((struct freeblks *));
  174 static  void merge_inode_lists __P((struct inodedep *));
  175 static  void setup_allocindir_phase2 __P((struct buf *, struct inode *,
  176             struct allocindir *));
  177 static  struct allocindir *newallocindir __P((struct inode *, int, ufs_daddr_t,
  178             ufs_daddr_t));
  179 static  void handle_workitem_freefrag __P((struct freefrag *));
  180 static  struct freefrag *newfreefrag __P((struct inode *, ufs_daddr_t, long));
  181 static  void allocdirect_merge __P((struct allocdirectlst *,
  182             struct allocdirect *, struct allocdirect *));
  183 static  struct bmsafemap *bmsafemap_lookup __P((struct buf *));
  184 static  int newblk_lookup __P((struct fs *, ufs_daddr_t, int,
  185             struct newblk **));
  186 static  int inodedep_lookup __P((struct fs *, ino_t, int, struct inodedep **));
  187 static  int pagedep_lookup __P((struct inode *, ufs_lbn_t, int,
  188             struct pagedep **));
  189 static  void pause_timer __P((void *));
  190 static  int request_cleanup __P((int, int));
  191 static  int process_worklist_item __P((struct mount *, int));
  192 static  void add_to_worklist __P((struct worklist *));
  193 
  194 /*
  195  * Exported softdep operations.
  196  */
  197 static  void softdep_disk_io_initiation __P((struct buf *));
  198 static  void softdep_disk_write_complete __P((struct buf *));
  199 static  void softdep_deallocate_dependencies __P((struct buf *));
  200 static  int softdep_fsync __P((struct vnode *));
  201 static  int softdep_process_worklist __P((struct mount *));
  202 static  void softdep_move_dependencies __P((struct buf *, struct buf *));
  203 static  int softdep_count_dependencies __P((struct buf *bp, int));
  204 
  205 struct bio_ops bioops = {
  206         softdep_disk_io_initiation,             /* io_start */
  207         softdep_disk_write_complete,            /* io_complete */
  208         softdep_deallocate_dependencies,        /* io_deallocate */
  209         softdep_fsync,                          /* io_fsync */
  210         softdep_process_worklist,               /* io_sync */
  211         softdep_move_dependencies,              /* io_movedeps */
  212         softdep_count_dependencies,             /* io_countdeps */
  213 };
  214 
  215 /*
  216  * Locking primitives.
  217  *
  218  * For a uniprocessor, all we need to do is protect against disk
  219  * interrupts. For a multiprocessor, this lock would have to be
  220  * a mutex. A single mutex is used throughout this file, though
  221  * finer grain locking could be used if contention warranted it.
  222  *
  223  * For a multiprocessor, the sleep call would accept a lock and
  224  * release it after the sleep processing was complete. In a uniprocessor
  225  * implementation there is no such interlock, so we simple mark
  226  * the places where it needs to be done with the `interlocked' form
  227  * of the lock calls. Since the uniprocessor sleep already interlocks
  228  * the spl, there is nothing that really needs to be done.
  229  */
  230 #ifndef /* NOT */ DEBUG
  231 static struct lockit {
  232         int     lkt_spl;
  233 } lk = { 0 };
  234 #define ACQUIRE_LOCK(lk)                (lk)->lkt_spl = splbio()
  235 #define FREE_LOCK(lk)                   splx((lk)->lkt_spl)
  236 
  237 #else /* DEBUG */
  238 static struct lockit {
  239         int     lkt_spl;
  240         pid_t   lkt_held;
  241 } lk = { 0, -1 };
  242 static int lockcnt;
  243 
  244 static  void acquire_lock __P((struct lockit *));
  245 static  void free_lock __P((struct lockit *));
  246 void    softdep_panic __P((char *));
  247 
  248 #define ACQUIRE_LOCK(lk)                acquire_lock(lk)
  249 #define FREE_LOCK(lk)                   free_lock(lk)
  250 
  251 static void
  252 acquire_lock(lk)
  253         struct lockit *lk;
  254 {
  255         pid_t holder;
  256 
  257         if (lk->lkt_held != -1) {
  258                 holder = lk->lkt_held;
  259                 FREE_LOCK(lk);
  260                 if (holder == CURPROC->p_pid)
  261                         panic("softdep_lock: locking against myself");
  262                 else
  263                         panic("softdep_lock: lock held by %d", holder);
  264         }
  265         lk->lkt_spl = splbio();
  266         lk->lkt_held = CURPROC->p_pid;
  267         lockcnt++;
  268 }
  269 
  270 static void
  271 free_lock(lk)
  272         struct lockit *lk;
  273 {
  274 
  275         if (lk->lkt_held == -1)
  276                 panic("softdep_unlock: lock not held");
  277         lk->lkt_held = -1;
  278         splx(lk->lkt_spl);
  279 }
  280 
  281 /*
  282  * Function to release soft updates lock and panic.
  283  */
  284 void
  285 softdep_panic(msg)
  286         char *msg;
  287 {
  288 
  289         if (lk.lkt_held != -1)
  290                 FREE_LOCK(&lk);
  291         panic(msg);
  292 }
  293 #endif /* DEBUG */
  294 
  295 static  int interlocked_sleep __P((struct lockit *, int, void *, int,
  296             const char *, int));
  297 
  298 /*
  299  * When going to sleep, we must save our SPL so that it does
  300  * not get lost if some other process uses the lock while we
  301  * are sleeping. We restore it after we have slept. This routine
  302  * wraps the interlocking with functions that sleep. The list
  303  * below enumerates the available set of operations.
  304  */
  305 #define UNKNOWN         0
  306 #define SLEEP           1
  307 #define LOCKBUF         2
  308 
  309 static int
  310 interlocked_sleep(lk, op, ident, flags, wmesg, timo)
  311         struct lockit *lk;
  312         int op;
  313         void *ident;
  314         int flags;
  315         const char *wmesg;
  316         int timo;
  317 {
  318         pid_t holder;
  319         int s, retval;
  320 
  321         s = lk->lkt_spl;
  322 #       ifdef DEBUG
  323         if (lk->lkt_held == -1)
  324                 panic("interlocked_sleep: lock not held");
  325         lk->lkt_held = -1;
  326 #       endif /* DEBUG */
  327         switch (op) {
  328         case SLEEP:
  329                 retval = tsleep(ident, flags, wmesg, timo);
  330                 break;
  331         case LOCKBUF:
  332                 retval = BUF_LOCK((struct buf *)ident, flags);
  333                 break;
  334         default:
  335                 panic("interlocked_sleep: unknown operation");
  336         }
  337 #       ifdef DEBUG
  338         if (lk->lkt_held != -1) {
  339                 holder = lk->lkt_held;
  340                 FREE_LOCK(lk);
  341                 if (holder == CURPROC->p_pid)
  342                         panic("interlocked_sleep: locking against self");
  343                 else
  344                         panic("interlocked_sleep: lock held by %d", holder);
  345         }
  346         lk->lkt_held = CURPROC->p_pid;
  347         lockcnt++;
  348 #       endif /* DEBUG */
  349         lk->lkt_spl = s;
  350         return (retval);
  351 }
  352 
  353 /*
  354  * Place holder for real semaphores.
  355  */
  356 struct sema {
  357         int     value;
  358         pid_t   holder;
  359         char    *name;
  360         int     prio;
  361         int     timo;
  362 };
  363 static  void sema_init __P((struct sema *, char *, int, int));
  364 static  int sema_get __P((struct sema *, struct lockit *));
  365 static  void sema_release __P((struct sema *));
  366 
  367 static void
  368 sema_init(semap, name, prio, timo)
  369         struct sema *semap;
  370         char *name;
  371         int prio, timo;
  372 {
  373 
  374         semap->holder = -1;
  375         semap->value = 0;
  376         semap->name = name;
  377         semap->prio = prio;
  378         semap->timo = timo;
  379 }
  380 
  381 static int
  382 sema_get(semap, interlock)
  383         struct sema *semap;
  384         struct lockit *interlock;
  385 {
  386 
  387         if (semap->value++ > 0) {
  388                 if (interlock != NULL) {
  389                         interlocked_sleep(interlock, SLEEP, (caddr_t)semap,
  390                             semap->prio, semap->name, semap->timo);
  391                         FREE_LOCK(interlock);
  392                 } else {
  393                         tsleep((caddr_t)semap, semap->prio, semap->name,
  394                             semap->timo);
  395                 }
  396                 return (0);
  397         }
  398         semap->holder = CURPROC->p_pid;
  399         if (interlock != NULL)
  400                 FREE_LOCK(interlock);
  401         return (1);
  402 }
  403 
  404 static void
  405 sema_release(semap)
  406         struct sema *semap;
  407 {
  408 
  409         if (semap->value <= 0 || semap->holder != CURPROC->p_pid) {
  410                 if (lk.lkt_held != -1)
  411                         FREE_LOCK(&lk);
  412                 panic("sema_release: not held");
  413         }
  414         if (--semap->value > 0) {
  415                 semap->value = 0;
  416                 wakeup(semap);
  417         }
  418         semap->holder = -1;
  419 }
  420 
  421 /*
  422  * Worklist queue management.
  423  * These routines require that the lock be held.
  424  */
  425 #ifndef /* NOT */ DEBUG
  426 #define WORKLIST_INSERT(head, item) do {        \
  427         (item)->wk_state |= ONWORKLIST;         \
  428         LIST_INSERT_HEAD(head, item, wk_list);  \
  429 } while (0)
  430 #define WORKLIST_REMOVE(item) do {              \
  431         (item)->wk_state &= ~ONWORKLIST;        \
  432         LIST_REMOVE(item, wk_list);             \
  433 } while (0)
  434 #define WORKITEM_FREE(item, type) FREE(item, DtoM(type))
  435 
  436 #else /* DEBUG */
  437 static  void worklist_insert __P((struct workhead *, struct worklist *));
  438 static  void worklist_remove __P((struct worklist *));
  439 static  void workitem_free __P((struct worklist *, int));
  440 
  441 #define WORKLIST_INSERT(head, item) worklist_insert(head, item)
  442 #define WORKLIST_REMOVE(item) worklist_remove(item)
  443 #define WORKITEM_FREE(item, type) workitem_free((struct worklist *)item, type)
  444 
  445 static void
  446 worklist_insert(head, item)
  447         struct workhead *head;
  448         struct worklist *item;
  449 {
  450 
  451         if (lk.lkt_held == -1)
  452                 panic("worklist_insert: lock not held");
  453         if (item->wk_state & ONWORKLIST) {
  454                 FREE_LOCK(&lk);
  455                 panic("worklist_insert: already on list");
  456         }
  457         item->wk_state |= ONWORKLIST;
  458         LIST_INSERT_HEAD(head, item, wk_list);
  459 }
  460 
  461 static void
  462 worklist_remove(item)
  463         struct worklist *item;
  464 {
  465 
  466         if (lk.lkt_held == -1)
  467                 panic("worklist_remove: lock not held");
  468         if ((item->wk_state & ONWORKLIST) == 0) {
  469                 FREE_LOCK(&lk);
  470                 panic("worklist_remove: not on list");
  471         }
  472         item->wk_state &= ~ONWORKLIST;
  473         LIST_REMOVE(item, wk_list);
  474 }
  475 
  476 static void
  477 workitem_free(item, type)
  478         struct worklist *item;
  479         int type;
  480 {
  481 
  482         if (item->wk_state & ONWORKLIST) {
  483                 if (lk.lkt_held != -1)
  484                         FREE_LOCK(&lk);
  485                 panic("workitem_free: still on list");
  486         }
  487         if (item->wk_type != type) {
  488                 if (lk.lkt_held != -1)
  489                         FREE_LOCK(&lk);
  490                 panic("workitem_free: type mismatch");
  491         }
  492         FREE(item, DtoM(type));
  493 }
  494 #endif /* DEBUG */
  495 
  496 /*
  497  * Workitem queue management
  498  */
  499 static struct workhead softdep_workitem_pending;
  500 static int num_on_worklist;     /* number of worklist items to be processed */
  501 static int softdep_worklist_busy; /* 1 => trying to do unmount */
  502 static int softdep_worklist_req; /* serialized waiters */
  503 static int max_softdeps;        /* maximum number of structs before slowdown */
  504 static int tickdelay = 2;       /* number of ticks to pause during slowdown */
  505 static int *stat_countp;        /* statistic to count in proc_waiting timeout */
  506 static int proc_waiting;        /* tracks whether we have a timeout posted */
  507 static struct callout_handle handle; /* handle on posted proc_waiting timeout */
  508 static struct proc *filesys_syncer; /* proc of filesystem syncer process */
  509 static int req_clear_inodedeps; /* syncer process flush some inodedeps */
  510 #define FLUSH_INODES    1
  511 static int req_clear_remove;    /* syncer process flush some freeblks */
  512 #define FLUSH_REMOVE    2
  513 /*
  514  * runtime statistics
  515  */
  516 static int stat_worklist_push;  /* number of worklist cleanups */
  517 static int stat_blk_limit_push; /* number of times block limit neared */
  518 static int stat_ino_limit_push; /* number of times inode limit neared */
  519 static int stat_blk_limit_hit;  /* number of times block slowdown imposed */
  520 static int stat_ino_limit_hit;  /* number of times inode slowdown imposed */
  521 static int stat_sync_limit_hit; /* number of synchronous slowdowns imposed */
  522 static int stat_indir_blk_ptrs; /* bufs redirtied as indir ptrs not written */
  523 static int stat_inode_bitmap;   /* bufs redirtied as inode bitmap not written */
  524 static int stat_direct_blk_ptrs;/* bufs redirtied as direct ptrs not written */
  525 static int stat_dir_entry;      /* bufs redirtied as dir entry cannot write */
  526 #ifdef DEBUG
  527 #include <vm/vm.h>
  528 #include <sys/sysctl.h>
  529 SYSCTL_INT(_debug, OID_AUTO, max_softdeps, CTLFLAG_RW, &max_softdeps, 0, "");
  530 SYSCTL_INT(_debug, OID_AUTO, tickdelay, CTLFLAG_RW, &tickdelay, 0, "");
  531 SYSCTL_INT(_debug, OID_AUTO, worklist_push, CTLFLAG_RW, &stat_worklist_push, 0,"");
  532 SYSCTL_INT(_debug, OID_AUTO, blk_limit_push, CTLFLAG_RW, &stat_blk_limit_push, 0,"");
  533 SYSCTL_INT(_debug, OID_AUTO, ino_limit_push, CTLFLAG_RW, &stat_ino_limit_push, 0,"");
  534 SYSCTL_INT(_debug, OID_AUTO, blk_limit_hit, CTLFLAG_RW, &stat_blk_limit_hit, 0, "");
  535 SYSCTL_INT(_debug, OID_AUTO, ino_limit_hit, CTLFLAG_RW, &stat_ino_limit_hit, 0, "");
  536 SYSCTL_INT(_debug, OID_AUTO, sync_limit_hit, CTLFLAG_RW, &stat_sync_limit_hit, 0, "");
  537 SYSCTL_INT(_debug, OID_AUTO, indir_blk_ptrs, CTLFLAG_RW, &stat_indir_blk_ptrs, 0, "");
  538 SYSCTL_INT(_debug, OID_AUTO, inode_bitmap, CTLFLAG_RW, &stat_inode_bitmap, 0, "");
  539 SYSCTL_INT(_debug, OID_AUTO, direct_blk_ptrs, CTLFLAG_RW, &stat_direct_blk_ptrs, 0, "");
  540 SYSCTL_INT(_debug, OID_AUTO, dir_entry, CTLFLAG_RW, &stat_dir_entry, 0, "");
  541 #endif /* DEBUG */
  542 
  543 /*
  544  * Add an item to the end of the work queue.
  545  * This routine requires that the lock be held.
  546  * This is the only routine that adds items to the list.
  547  * The following routine is the only one that removes items
  548  * and does so in order from first to last.
  549  */
  550 static void
  551 add_to_worklist(wk)
  552         struct worklist *wk;
  553 {
  554         static struct worklist *worklist_tail;
  555 
  556         if (wk->wk_state & ONWORKLIST) {
  557                 if (lk.lkt_held != -1)
  558                         FREE_LOCK(&lk);
  559                 panic("add_to_worklist: already on list");
  560         }
  561         wk->wk_state |= ONWORKLIST;
  562         if (LIST_FIRST(&softdep_workitem_pending) == NULL)
  563                 LIST_INSERT_HEAD(&softdep_workitem_pending, wk, wk_list);
  564         else
  565                 LIST_INSERT_AFTER(worklist_tail, wk, wk_list);
  566         worklist_tail = wk;
  567         num_on_worklist += 1;
  568 }
  569 
  570 /*
  571  * Process that runs once per second to handle items in the background queue.
  572  *
  573  * Note that we ensure that everything is done in the order in which they
  574  * appear in the queue. The code below depends on this property to ensure
  575  * that blocks of a file are freed before the inode itself is freed. This
  576  * ordering ensures that no new <vfsid, inum, lbn> triples will be generated
  577  * until all the old ones have been purged from the dependency lists.
  578  */
  579 static int 
  580 softdep_process_worklist(matchmnt)
  581         struct mount *matchmnt;
  582 {
  583         struct proc *p = CURPROC;
  584         int matchcnt, loopcount;
  585         long starttime;
  586 
  587         /*
  588          * Record the process identifier of our caller so that we can give
  589          * this process preferential treatment in request_cleanup below.
  590          */
  591         filesys_syncer = p;
  592         matchcnt = 0;
  593 
  594         /*
  595          * There is no danger of having multiple processes run this
  596          * code, but we have to single-thread it when softdep_flushfiles()
  597          * is in operation to get an accurate count of the number of items
  598          * related to its mount point that are in the list.
  599          */
  600         if (matchmnt == NULL) {
  601                 if (softdep_worklist_busy < 0)
  602                         return(-1);
  603                 softdep_worklist_busy += 1;
  604         }
  605 
  606         /*
  607          * If requested, try removing inode or removal dependencies.
  608          */
  609         if (req_clear_inodedeps) {
  610                 clear_inodedeps(p);
  611                 req_clear_inodedeps -= 1;
  612                 wakeup_one(&proc_waiting);
  613         }
  614         if (req_clear_remove) {
  615                 clear_remove(p);
  616                 req_clear_remove -= 1;
  617                 wakeup_one(&proc_waiting);
  618         }
  619         loopcount = 1;
  620         starttime = time_second;
  621         while (num_on_worklist > 0) {
  622                 matchcnt += process_worklist_item(matchmnt, 0);
  623 
  624                 /*
  625                  * If a umount operation wants to run the worklist
  626                  * accurately, abort.
  627                  */
  628                 if (softdep_worklist_req && matchmnt == NULL) {
  629                         matchcnt = -1;
  630                         break;
  631                 }
  632 
  633                 /*
  634                  * If requested, try removing inode or removal dependencies.
  635                  */
  636                 if (req_clear_inodedeps) {
  637                         clear_inodedeps(p);
  638                         req_clear_inodedeps -= 1;
  639                         wakeup_one(&proc_waiting);
  640                 }
  641                 if (req_clear_remove) {
  642                         clear_remove(p);
  643                         req_clear_remove -= 1;
  644                         wakeup_one(&proc_waiting);
  645                 }
  646                 /*
  647                  * We do not generally want to stop for buffer space, but if
  648                  * we are really being a buffer hog, we will stop and wait.
  649                  */
  650                 if (loopcount++ % 128 == 0)
  651                         bwillwrite();
  652                 /*
  653                  * Never allow processing to run for more than one
  654                  * second. Otherwise the other syncer tasks may get
  655                  * excessively backlogged.
  656                  */
  657                 if (starttime != time_second && matchmnt == NULL) {
  658                         matchcnt = -1;
  659                         break;
  660                 }
  661         }
  662         if (matchmnt == NULL) {
  663                 --softdep_worklist_busy;
  664                 if (softdep_worklist_req && softdep_worklist_busy == 0)
  665                         wakeup(&softdep_worklist_req);
  666         }
  667         return (matchcnt);
  668 }
  669 
  670 /*
  671  * Process one item on the worklist.
  672  */
  673 static int
  674 process_worklist_item(matchmnt, flags)
  675         struct mount *matchmnt;
  676         int flags;
  677 {
  678         struct worklist *wk;
  679         struct dirrem *dirrem;
  680         struct fs *matchfs;
  681         struct vnode *vp;
  682         int matchcnt = 0;
  683 
  684         matchfs = NULL;
  685         if (matchmnt != NULL)
  686                 matchfs = VFSTOUFS(matchmnt)->um_fs;
  687         ACQUIRE_LOCK(&lk);
  688         /*
  689          * Normally we just process each item on the worklist in order.
  690          * However, if we are in a situation where we cannot lock any
  691          * inodes, we have to skip over any dirrem requests whose
  692          * vnodes are resident and locked.
  693          */
  694         LIST_FOREACH(wk, &softdep_workitem_pending, wk_list) {
  695                 if ((flags & LK_NOWAIT) == 0 || wk->wk_type != D_DIRREM)
  696                         break;
  697                 dirrem = WK_DIRREM(wk);
  698                 vp = ufs_ihashlookup(VFSTOUFS(dirrem->dm_mnt)->um_dev,
  699                     dirrem->dm_oldinum);
  700                 if (vp == NULL || !VOP_ISLOCKED(vp, CURPROC))
  701                         break;
  702         }
  703         if (wk == 0) {
  704                 FREE_LOCK(&lk);
  705                 return (0);
  706         }
  707         WORKLIST_REMOVE(wk);
  708         num_on_worklist -= 1;
  709         FREE_LOCK(&lk);
  710         switch (wk->wk_type) {
  711 
  712         case D_DIRREM:
  713                 /* removal of a directory entry */
  714                 if (WK_DIRREM(wk)->dm_mnt == matchmnt)
  715                         matchcnt += 1;
  716                 handle_workitem_remove(WK_DIRREM(wk));
  717                 break;
  718 
  719         case D_FREEBLKS:
  720                 /* releasing blocks and/or fragments from a file */
  721                 if (WK_FREEBLKS(wk)->fb_fs == matchfs)
  722                         matchcnt += 1;
  723                 handle_workitem_freeblocks(WK_FREEBLKS(wk));
  724                 break;
  725 
  726         case D_FREEFRAG:
  727                 /* releasing a fragment when replaced as a file grows */
  728                 if (WK_FREEFRAG(wk)->ff_fs == matchfs)
  729                         matchcnt += 1;
  730                 handle_workitem_freefrag(WK_FREEFRAG(wk));
  731                 break;
  732 
  733         case D_FREEFILE:
  734                 /* releasing an inode when its link count drops to 0 */
  735                 if (WK_FREEFILE(wk)->fx_fs == matchfs)
  736                         matchcnt += 1;
  737                 handle_workitem_freefile(WK_FREEFILE(wk));
  738                 break;
  739 
  740         default:
  741                 panic("%s_process_worklist: Unknown type %s",
  742                     "softdep", TYPENAME(wk->wk_type));
  743                 /* NOTREACHED */
  744         }
  745         return (matchcnt);
  746 }
  747 
  748 /*
  749  * Move dependencies from one buffer to another.
  750  */
  751 static void
  752 softdep_move_dependencies(oldbp, newbp)
  753         struct buf *oldbp;
  754         struct buf *newbp;
  755 {
  756         struct worklist *wk, *wktail;
  757 
  758         if (LIST_FIRST(&newbp->b_dep) != NULL)
  759                 panic("softdep_move_dependencies: need merge code");
  760         wktail = 0;
  761         ACQUIRE_LOCK(&lk);
  762         while ((wk = LIST_FIRST(&oldbp->b_dep)) != NULL) {
  763                 LIST_REMOVE(wk, wk_list);
  764                 if (wktail == 0)
  765                         LIST_INSERT_HEAD(&newbp->b_dep, wk, wk_list);
  766                 else
  767                         LIST_INSERT_AFTER(wktail, wk, wk_list);
  768                 wktail = wk;
  769         }
  770         FREE_LOCK(&lk);
  771 }
  772 
  773 /*
  774  * Purge the work list of all items associated with a particular mount point.
  775  */
  776 int
  777 softdep_flushfiles(oldmnt, flags, p)
  778         struct mount *oldmnt;
  779         int flags;
  780         struct proc *p;
  781 {
  782         struct vnode *devvp;
  783         int error, loopcnt;
  784 
  785         /*
  786          * Await our turn to clear out the queue, then serialize access.
  787          */
  788         while (softdep_worklist_busy != 0) {
  789                 softdep_worklist_req += 1;
  790                 tsleep(&softdep_worklist_req, PRIBIO, "softflush", 0);
  791                 softdep_worklist_req -= 1;
  792         }
  793         softdep_worklist_busy = -1;
  794 
  795         if ((error = ffs_flushfiles(oldmnt, flags, p)) != 0) {
  796                 softdep_worklist_busy = 0;
  797                 if (softdep_worklist_req)
  798                         wakeup(&softdep_worklist_req);
  799                 return (error);
  800         }
  801         /*
  802          * Alternately flush the block device associated with the mount
  803          * point and process any dependencies that the flushing
  804          * creates. In theory, this loop can happen at most twice,
  805          * but we give it a few extra just to be sure.
  806          */
  807         devvp = VFSTOUFS(oldmnt)->um_devvp;
  808         for (loopcnt = 10; loopcnt > 0; ) {
  809                 if (softdep_process_worklist(oldmnt) == 0) {
  810                         loopcnt--;
  811                         /*
  812                          * Do another flush in case any vnodes were brought in
  813                          * as part of the cleanup operations.
  814                          */
  815                         if ((error = ffs_flushfiles(oldmnt, flags, p)) != 0)
  816                                 break;
  817                         /*
  818                          * If we still found nothing to do, we are really done.
  819                          */
  820                         if (softdep_process_worklist(oldmnt) == 0)
  821                                 break;
  822                 }
  823                 vn_lock(devvp, LK_EXCLUSIVE | LK_RETRY, p);
  824                 error = VOP_FSYNC(devvp, p->p_ucred, MNT_WAIT, p);
  825                 VOP_UNLOCK(devvp, 0, p);
  826                 if (error)
  827                         break;
  828         }
  829         softdep_worklist_busy = 0;
  830         if (softdep_worklist_req)
  831                 wakeup(&softdep_worklist_req);
  832 
  833         /*
  834          * If we are unmounting then it is an error to fail. If we
  835          * are simply trying to downgrade to read-only, then filesystem
  836          * activity can keep us busy forever, so we just fail with EBUSY.
  837          */
  838         if (loopcnt == 0) {
  839                 if (oldmnt->mnt_kern_flag & MNTK_UNMOUNT)
  840                         panic("softdep_flushfiles: looping");
  841                 error = EBUSY;
  842         }
  843         return (error);
  844 }
  845 
  846 /*
  847  * Structure hashing.
  848  * 
  849  * There are three types of structures that can be looked up:
  850  *      1) pagedep structures identified by mount point, inode number,
  851  *         and logical block.
  852  *      2) inodedep structures identified by mount point and inode number.
  853  *      3) newblk structures identified by mount point and
  854  *         physical block number.
  855  *
  856  * The "pagedep" and "inodedep" dependency structures are hashed
  857  * separately from the file blocks and inodes to which they correspond.
  858  * This separation helps when the in-memory copy of an inode or
  859  * file block must be replaced. It also obviates the need to access
  860  * an inode or file page when simply updating (or de-allocating)
  861  * dependency structures. Lookup of newblk structures is needed to
  862  * find newly allocated blocks when trying to associate them with
  863  * their allocdirect or allocindir structure.
  864  *
  865  * The lookup routines optionally create and hash a new instance when
  866  * an existing entry is not found.
  867  */
  868 #define DEPALLOC        0x0001  /* allocate structure if lookup fails */
  869 #define NODELAY         0x0002  /* cannot do background work */
  870 
  871 /*
  872  * Structures and routines associated with pagedep caching.
  873  */
  874 LIST_HEAD(pagedep_hashhead, pagedep) *pagedep_hashtbl;
  875 u_long  pagedep_hash;           /* size of hash table - 1 */
  876 #define PAGEDEP_HASH(mp, inum, lbn) \
  877         (&pagedep_hashtbl[((((register_t)(mp)) >> 13) + (inum) + (lbn)) & \
  878             pagedep_hash])
  879 static struct sema pagedep_in_progress;
  880 
  881 /*
  882  * Look up a pagedep. Return 1 if found, 0 if not found.
  883  * If not found, allocate if DEPALLOC flag is passed.
  884  * Found or allocated entry is returned in pagedeppp.
  885  * This routine must be called with splbio interrupts blocked.
  886  */
  887 static int
  888 pagedep_lookup(ip, lbn, flags, pagedeppp)
  889         struct inode *ip;
  890         ufs_lbn_t lbn;
  891         int flags;
  892         struct pagedep **pagedeppp;
  893 {
  894         struct pagedep *pagedep;
  895         struct pagedep_hashhead *pagedephd;
  896         struct mount *mp;
  897         int i;
  898 
  899 #ifdef DEBUG
  900         if (lk.lkt_held == -1)
  901                 panic("pagedep_lookup: lock not held");
  902 #endif
  903         mp = ITOV(ip)->v_mount;
  904         pagedephd = PAGEDEP_HASH(mp, ip->i_number, lbn);
  905 top:
  906         LIST_FOREACH(pagedep, pagedephd, pd_hash)
  907                 if (ip->i_number == pagedep->pd_ino &&
  908                     lbn == pagedep->pd_lbn &&
  909                     mp == pagedep->pd_mnt)
  910                         break;
  911         if (pagedep) {
  912                 *pagedeppp = pagedep;
  913                 return (1);
  914         }
  915         if ((flags & DEPALLOC) == 0) {
  916                 *pagedeppp = NULL;
  917                 return (0);
  918         }
  919         if (sema_get(&pagedep_in_progress, &lk) == 0) {
  920                 ACQUIRE_LOCK(&lk);
  921                 goto top;
  922         }
  923         MALLOC(pagedep, struct pagedep *, sizeof(struct pagedep), M_PAGEDEP,
  924                 M_SOFTDEP_FLAGS);
  925         bzero(pagedep, sizeof(struct pagedep));
  926         pagedep->pd_list.wk_type = D_PAGEDEP;
  927         pagedep->pd_mnt = mp;
  928         pagedep->pd_ino = ip->i_number;
  929         pagedep->pd_lbn = lbn;
  930         LIST_INIT(&pagedep->pd_dirremhd);
  931         LIST_INIT(&pagedep->pd_pendinghd);
  932         for (i = 0; i < DAHASHSZ; i++)
  933                 LIST_INIT(&pagedep->pd_diraddhd[i]);
  934         ACQUIRE_LOCK(&lk);
  935         LIST_INSERT_HEAD(pagedephd, pagedep, pd_hash);
  936         sema_release(&pagedep_in_progress);
  937         *pagedeppp = pagedep;
  938         return (0);
  939 }
  940 
  941 /*
  942  * Structures and routines associated with inodedep caching.
  943  */
  944 LIST_HEAD(inodedep_hashhead, inodedep) *inodedep_hashtbl;
  945 static u_long   inodedep_hash;  /* size of hash table - 1 */
  946 static long     num_inodedep;   /* number of inodedep allocated */
  947 #define INODEDEP_HASH(fs, inum) \
  948       (&inodedep_hashtbl[((((register_t)(fs)) >> 13) + (inum)) & inodedep_hash])
  949 static struct sema inodedep_in_progress;
  950 
  951 /*
  952  * Look up a inodedep. Return 1 if found, 0 if not found.
  953  * If not found, allocate if DEPALLOC flag is passed.
  954  * Found or allocated entry is returned in inodedeppp.
  955  * This routine must be called with splbio interrupts blocked.
  956  */
  957 static int
  958 inodedep_lookup(fs, inum, flags, inodedeppp)
  959         struct fs *fs;
  960         ino_t inum;
  961         int flags;
  962         struct inodedep **inodedeppp;
  963 {
  964         struct inodedep *inodedep;
  965         struct inodedep_hashhead *inodedephd;
  966         int firsttry;
  967 
  968 #ifdef DEBUG
  969         if (lk.lkt_held == -1)
  970                 panic("inodedep_lookup: lock not held");
  971 #endif
  972         firsttry = 1;
  973         inodedephd = INODEDEP_HASH(fs, inum);
  974 top:
  975         LIST_FOREACH(inodedep, inodedephd, id_hash)
  976                 if (inum == inodedep->id_ino && fs == inodedep->id_fs)
  977                         break;
  978         if (inodedep) {
  979                 *inodedeppp = inodedep;
  980                 return (1);
  981         }
  982         if ((flags & DEPALLOC) == 0) {
  983                 *inodedeppp = NULL;
  984                 return (0);
  985         }
  986         /*
  987          * If we are over our limit, try to improve the situation.
  988          */
  989         if (num_inodedep > max_softdeps && firsttry && 
  990             speedup_syncer() == 0 && (flags & NODELAY) == 0 &&
  991             request_cleanup(FLUSH_INODES, 1)) {
  992                 firsttry = 0;
  993                 goto top;
  994         }
  995         if (sema_get(&inodedep_in_progress, &lk) == 0) {
  996                 ACQUIRE_LOCK(&lk);
  997                 goto top;
  998         }
  999         num_inodedep += 1;
 1000         MALLOC(inodedep, struct inodedep *, sizeof(struct inodedep),
 1001                 M_INODEDEP, M_SOFTDEP_FLAGS);
 1002         inodedep->id_list.wk_type = D_INODEDEP;
 1003         inodedep->id_fs = fs;
 1004         inodedep->id_ino = inum;
 1005         inodedep->id_state = ALLCOMPLETE;
 1006         inodedep->id_nlinkdelta = 0;
 1007         inodedep->id_savedino = NULL;
 1008         inodedep->id_savedsize = -1;
 1009         inodedep->id_buf = NULL;
 1010         LIST_INIT(&inodedep->id_pendinghd);
 1011         LIST_INIT(&inodedep->id_inowait);
 1012         LIST_INIT(&inodedep->id_bufwait);
 1013         TAILQ_INIT(&inodedep->id_inoupdt);
 1014         TAILQ_INIT(&inodedep->id_newinoupdt);
 1015         ACQUIRE_LOCK(&lk);
 1016         LIST_INSERT_HEAD(inodedephd, inodedep, id_hash);
 1017         sema_release(&inodedep_in_progress);
 1018         *inodedeppp = inodedep;
 1019         return (0);
 1020 }
 1021 
 1022 /*
 1023  * Structures and routines associated with newblk caching.
 1024  */
 1025 LIST_HEAD(newblk_hashhead, newblk) *newblk_hashtbl;
 1026 u_long  newblk_hash;            /* size of hash table - 1 */
 1027 #define NEWBLK_HASH(fs, inum) \
 1028         (&newblk_hashtbl[((((register_t)(fs)) >> 13) + (inum)) & newblk_hash])
 1029 static struct sema newblk_in_progress;
 1030 
 1031 /*
 1032  * Look up a newblk. Return 1 if found, 0 if not found.
 1033  * If not found, allocate if DEPALLOC flag is passed.
 1034  * Found or allocated entry is returned in newblkpp.
 1035  */
 1036 static int
 1037 newblk_lookup(fs, newblkno, flags, newblkpp)
 1038         struct fs *fs;
 1039         ufs_daddr_t newblkno;
 1040         int flags;
 1041         struct newblk **newblkpp;
 1042 {
 1043         struct newblk *newblk;
 1044         struct newblk_hashhead *newblkhd;
 1045 
 1046         newblkhd = NEWBLK_HASH(fs, newblkno);
 1047 top:
 1048         LIST_FOREACH(newblk, newblkhd, nb_hash)
 1049                 if (newblkno == newblk->nb_newblkno && fs == newblk->nb_fs)
 1050                         break;
 1051         if (newblk) {
 1052                 *newblkpp = newblk;
 1053                 return (1);
 1054         }
 1055         if ((flags & DEPALLOC) == 0) {
 1056                 *newblkpp = NULL;
 1057                 return (0);
 1058         }
 1059         if (sema_get(&newblk_in_progress, 0) == 0)
 1060                 goto top;
 1061         MALLOC(newblk, struct newblk *, sizeof(struct newblk),
 1062                 M_NEWBLK, M_SOFTDEP_FLAGS);
 1063         newblk->nb_state = 0;
 1064         newblk->nb_fs = fs;
 1065         newblk->nb_newblkno = newblkno;
 1066         LIST_INSERT_HEAD(newblkhd, newblk, nb_hash);
 1067         sema_release(&newblk_in_progress);
 1068         *newblkpp = newblk;
 1069         return (0);
 1070 }
 1071 
 1072 /*
 1073  * Executed during filesystem system initialization before
 1074  * mounting any file systems.
 1075  */
 1076 void 
 1077 softdep_initialize()
 1078 {
 1079 
 1080         LIST_INIT(&mkdirlisthd);
 1081         LIST_INIT(&softdep_workitem_pending);
 1082         max_softdeps = min(desiredvnodes * 8,
 1083                 M_INODEDEP->ks_limit / (2 * sizeof(struct inodedep)));
 1084         pagedep_hashtbl = hashinit(desiredvnodes / 5, M_PAGEDEP,
 1085             &pagedep_hash);
 1086         sema_init(&pagedep_in_progress, "pagedep", PRIBIO, 0);
 1087         inodedep_hashtbl = hashinit(desiredvnodes, M_INODEDEP, &inodedep_hash);
 1088         sema_init(&inodedep_in_progress, "inodedep", PRIBIO, 0);
 1089         newblk_hashtbl = hashinit(64, M_NEWBLK, &newblk_hash);
 1090         sema_init(&newblk_in_progress, "newblk", PRIBIO, 0);
 1091 }
 1092 
 1093 /*
 1094  * Called at mount time to notify the dependency code that a
 1095  * filesystem wishes to use it.
 1096  */
 1097 int
 1098 softdep_mount(devvp, mp, fs, cred)
 1099         struct vnode *devvp;
 1100         struct mount *mp;
 1101         struct fs *fs;
 1102         struct ucred *cred;
 1103 {
 1104         struct csum cstotal;
 1105         struct cg *cgp;
 1106         struct buf *bp;
 1107         int error, cyl;
 1108 
 1109         mp->mnt_flag &= ~MNT_ASYNC;
 1110         mp->mnt_flag |= MNT_SOFTDEP;
 1111         /*
 1112          * When doing soft updates, the counters in the
 1113          * superblock may have gotten out of sync, so we have
 1114          * to scan the cylinder groups and recalculate them.
 1115          */
 1116         if (fs->fs_clean != 0)
 1117                 return (0);
 1118         bzero(&cstotal, sizeof cstotal);
 1119         for (cyl = 0; cyl < fs->fs_ncg; cyl++) {
 1120                 if ((error = bread(devvp, fsbtodb(fs, cgtod(fs, cyl)),
 1121                     fs->fs_cgsize, cred, &bp)) != 0) {
 1122                         brelse(bp);
 1123                         return (error);
 1124                 }
 1125                 cgp = (struct cg *)bp->b_data;
 1126                 cstotal.cs_nffree += cgp->cg_cs.cs_nffree;
 1127                 cstotal.cs_nbfree += cgp->cg_cs.cs_nbfree;
 1128                 cstotal.cs_nifree += cgp->cg_cs.cs_nifree;
 1129                 cstotal.cs_ndir += cgp->cg_cs.cs_ndir;
 1130                 fs->fs_cs(fs, cyl) = cgp->cg_cs;
 1131                 brelse(bp);
 1132         }
 1133 #ifdef DEBUG
 1134         if (bcmp(&cstotal, &fs->fs_cstotal, sizeof cstotal))
 1135                 printf("ffs_mountfs: superblock updated for soft updates\n");
 1136 #endif
 1137         bcopy(&cstotal, &fs->fs_cstotal, sizeof cstotal);
 1138         return (0);
 1139 }
 1140 
 1141 /*
 1142  * Protecting the freemaps (or bitmaps).
 1143  * 
 1144  * To eliminate the need to execute fsck before mounting a file system
 1145  * after a power failure, one must (conservatively) guarantee that the
 1146  * on-disk copy of the bitmaps never indicate that a live inode or block is
 1147  * free.  So, when a block or inode is allocated, the bitmap should be
 1148  * updated (on disk) before any new pointers.  When a block or inode is
 1149  * freed, the bitmap should not be updated until all pointers have been
 1150  * reset.  The latter dependency is handled by the delayed de-allocation
 1151  * approach described below for block and inode de-allocation.  The former
 1152  * dependency is handled by calling the following procedure when a block or
 1153  * inode is allocated. When an inode is allocated an "inodedep" is created
 1154  * with its DEPCOMPLETE flag cleared until its bitmap is written to disk.
 1155  * Each "inodedep" is also inserted into the hash indexing structure so
 1156  * that any additional link additions can be made dependent on the inode
 1157  * allocation.
 1158  * 
 1159  * The ufs file system maintains a number of free block counts (e.g., per
 1160  * cylinder group, per cylinder and per <cylinder, rotational position> pair)
 1161  * in addition to the bitmaps.  These counts are used to improve efficiency
 1162  * during allocation and therefore must be consistent with the bitmaps.
 1163  * There is no convenient way to guarantee post-crash consistency of these
 1164  * counts with simple update ordering, for two main reasons: (1) The counts
 1165  * and bitmaps for a single cylinder group block are not in the same disk
 1166  * sector.  If a disk write is interrupted (e.g., by power failure), one may
 1167  * be written and the other not.  (2) Some of the counts are located in the
 1168  * superblock rather than the cylinder group block. So, we focus our soft
 1169  * updates implementation on protecting the bitmaps. When mounting a
 1170  * filesystem, we recompute the auxiliary counts from the bitmaps.
 1171  */
 1172 
 1173 /*
 1174  * Called just after updating the cylinder group block to allocate an inode.
 1175  */
 1176 void
 1177 softdep_setup_inomapdep(bp, ip, newinum)
 1178         struct buf *bp;         /* buffer for cylgroup block with inode map */
 1179         struct inode *ip;       /* inode related to allocation */
 1180         ino_t newinum;          /* new inode number being allocated */
 1181 {
 1182         struct inodedep *inodedep;
 1183         struct bmsafemap *bmsafemap;
 1184 
 1185         /*
 1186          * Create a dependency for the newly allocated inode.
 1187          * Panic if it already exists as something is seriously wrong.
 1188          * Otherwise add it to the dependency list for the buffer holding
 1189          * the cylinder group map from which it was allocated.
 1190          */
 1191         ACQUIRE_LOCK(&lk);
 1192         if ((inodedep_lookup(ip->i_fs, newinum, DEPALLOC|NODELAY, &inodedep))) {
 1193                 FREE_LOCK(&lk);
 1194                 panic("softdep_setup_inomapdep: found inode");
 1195         }
 1196         inodedep->id_buf = bp;
 1197         inodedep->id_state &= ~DEPCOMPLETE;
 1198         bmsafemap = bmsafemap_lookup(bp);
 1199         LIST_INSERT_HEAD(&bmsafemap->sm_inodedephd, inodedep, id_deps);
 1200         FREE_LOCK(&lk);
 1201 }
 1202 
 1203 /*
 1204  * Called just after updating the cylinder group block to
 1205  * allocate block or fragment.
 1206  */
 1207 void
 1208 softdep_setup_blkmapdep(bp, fs, newblkno)
 1209         struct buf *bp;         /* buffer for cylgroup block with block map */
 1210         struct fs *fs;          /* filesystem doing allocation */
 1211         ufs_daddr_t newblkno;   /* number of newly allocated block */
 1212 {
 1213         struct newblk *newblk;
 1214         struct bmsafemap *bmsafemap;
 1215 
 1216         /*
 1217          * Create a dependency for the newly allocated block.
 1218          * Add it to the dependency list for the buffer holding
 1219          * the cylinder group map from which it was allocated.
 1220          */
 1221         if (newblk_lookup(fs, newblkno, DEPALLOC, &newblk) != 0)
 1222                 panic("softdep_setup_blkmapdep: found block");
 1223         ACQUIRE_LOCK(&lk);
 1224         newblk->nb_bmsafemap = bmsafemap = bmsafemap_lookup(bp);
 1225         LIST_INSERT_HEAD(&bmsafemap->sm_newblkhd, newblk, nb_deps);
 1226         FREE_LOCK(&lk);
 1227 }
 1228 
 1229 /*
 1230  * Find the bmsafemap associated with a cylinder group buffer.
 1231  * If none exists, create one. The buffer must be locked when
 1232  * this routine is called and this routine must be called with
 1233  * splbio interrupts blocked.
 1234  */
 1235 static struct bmsafemap *
 1236 bmsafemap_lookup(bp)
 1237         struct buf *bp;
 1238 {
 1239         struct bmsafemap *bmsafemap;
 1240         struct worklist *wk;
 1241 
 1242 #ifdef DEBUG
 1243         if (lk.lkt_held == -1)
 1244                 panic("bmsafemap_lookup: lock not held");
 1245 #endif
 1246         LIST_FOREACH(wk, &bp->b_dep, wk_list)
 1247                 if (wk->wk_type == D_BMSAFEMAP)
 1248                         return (WK_BMSAFEMAP(wk));
 1249         FREE_LOCK(&lk);
 1250         MALLOC(bmsafemap, struct bmsafemap *, sizeof(struct bmsafemap),
 1251                 M_BMSAFEMAP, M_SOFTDEP_FLAGS);
 1252         bmsafemap->sm_list.wk_type = D_BMSAFEMAP;
 1253         bmsafemap->sm_list.wk_state = 0;
 1254         bmsafemap->sm_buf = bp;
 1255         LIST_INIT(&bmsafemap->sm_allocdirecthd);
 1256         LIST_INIT(&bmsafemap->sm_allocindirhd);
 1257         LIST_INIT(&bmsafemap->sm_inodedephd);
 1258         LIST_INIT(&bmsafemap->sm_newblkhd);
 1259         ACQUIRE_LOCK(&lk);
 1260         WORKLIST_INSERT(&bp->b_dep, &bmsafemap->sm_list);
 1261         return (bmsafemap);
 1262 }
 1263 
 1264 /*
 1265  * Direct block allocation dependencies.
 1266  * 
 1267  * When a new block is allocated, the corresponding disk locations must be
 1268  * initialized (with zeros or new data) before the on-disk inode points to
 1269  * them.  Also, the freemap from which the block was allocated must be
 1270  * updated (on disk) before the inode's pointer. These two dependencies are
 1271  * independent of each other and are needed for all file blocks and indirect
 1272  * blocks that are pointed to directly by the inode.  Just before the
 1273  * "in-core" version of the inode is updated with a newly allocated block
 1274  * number, a procedure (below) is called to setup allocation dependency
 1275  * structures.  These structures are removed when the corresponding
 1276  * dependencies are satisfied or when the block allocation becomes obsolete
 1277  * (i.e., the file is deleted, the block is de-allocated, or the block is a
 1278  * fragment that gets upgraded).  All of these cases are handled in
 1279  * procedures described later.
 1280  * 
 1281  * When a file extension causes a fragment to be upgraded, either to a larger
 1282  * fragment or to a full block, the on-disk location may change (if the
 1283  * previous fragment could not simply be extended). In this case, the old
 1284  * fragment must be de-allocated, but not until after the inode's pointer has
 1285  * been updated. In most cases, this is handled by later procedures, which
 1286  * will construct a "freefrag" structure to be added to the workitem queue
 1287  * when the inode update is complete (or obsolete).  The main exception to
 1288  * this is when an allocation occurs while a pending allocation dependency
 1289  * (for the same block pointer) remains.  This case is handled in the main
 1290  * allocation dependency setup procedure by immediately freeing the
 1291  * unreferenced fragments.
 1292  */ 
 1293 void 
 1294 softdep_setup_allocdirect(ip, lbn, newblkno, oldblkno, newsize, oldsize, bp)
 1295         struct inode *ip;       /* inode to which block is being added */
 1296         ufs_lbn_t lbn;          /* block pointer within inode */
 1297         ufs_daddr_t newblkno;   /* disk block number being added */
 1298         ufs_daddr_t oldblkno;   /* previous block number, 0 unless frag */
 1299         long newsize;           /* size of new block */
 1300         long oldsize;           /* size of new block */
 1301         struct buf *bp;         /* bp for allocated block */
 1302 {
 1303         struct allocdirect *adp, *oldadp;
 1304         struct allocdirectlst *adphead;
 1305         struct bmsafemap *bmsafemap;
 1306         struct inodedep *inodedep;
 1307         struct pagedep *pagedep;
 1308         struct newblk *newblk;
 1309 
 1310         MALLOC(adp, struct allocdirect *, sizeof(struct allocdirect),
 1311                 M_ALLOCDIRECT, M_SOFTDEP_FLAGS);
 1312         bzero(adp, sizeof(struct allocdirect));
 1313         adp->ad_list.wk_type = D_ALLOCDIRECT;
 1314         adp->ad_lbn = lbn;
 1315         adp->ad_newblkno = newblkno;
 1316         adp->ad_oldblkno = oldblkno;
 1317         adp->ad_newsize = newsize;
 1318         adp->ad_oldsize = oldsize;
 1319         adp->ad_state = ATTACHED;
 1320         if (newblkno == oldblkno)
 1321                 adp->ad_freefrag = NULL;
 1322         else
 1323                 adp->ad_freefrag = newfreefrag(ip, oldblkno, oldsize);
 1324 
 1325         if (newblk_lookup(ip->i_fs, newblkno, 0, &newblk) == 0)
 1326                 panic("softdep_setup_allocdirect: lost block");
 1327 
 1328         ACQUIRE_LOCK(&lk);
 1329         inodedep_lookup(ip->i_fs, ip->i_number, DEPALLOC | NODELAY, &inodedep);
 1330         adp->ad_inodedep = inodedep;
 1331 
 1332         if (newblk->nb_state == DEPCOMPLETE) {
 1333                 adp->ad_state |= DEPCOMPLETE;
 1334                 adp->ad_buf = NULL;
 1335         } else {
 1336                 bmsafemap = newblk->nb_bmsafemap;
 1337                 adp->ad_buf = bmsafemap->sm_buf;
 1338                 LIST_REMOVE(newblk, nb_deps);
 1339                 LIST_INSERT_HEAD(&bmsafemap->sm_allocdirecthd, adp, ad_deps);
 1340         }
 1341         LIST_REMOVE(newblk, nb_hash);
 1342         FREE(newblk, M_NEWBLK);
 1343 
 1344         WORKLIST_INSERT(&bp->b_dep, &adp->ad_list);
 1345         if (lbn >= NDADDR) {
 1346                 /* allocating an indirect block */
 1347                 if (oldblkno != 0) {
 1348                         FREE_LOCK(&lk);
 1349                         panic("softdep_setup_allocdirect: non-zero indir");
 1350                 }
 1351         } else {
 1352                 /*
 1353                  * Allocating a direct block.
 1354                  *
 1355                  * If we are allocating a directory block, then we must
 1356                  * allocate an associated pagedep to track additions and
 1357                  * deletions.
 1358                  */
 1359                 if ((ip->i_mode & IFMT) == IFDIR &&
 1360                     pagedep_lookup(ip, lbn, DEPALLOC, &pagedep) == 0)
 1361                         WORKLIST_INSERT(&bp->b_dep, &pagedep->pd_list);
 1362         }
 1363         /*
 1364          * The list of allocdirects must be kept in sorted and ascending
 1365          * order so that the rollback routines can quickly determine the
 1366          * first uncommitted block (the size of the file stored on disk
 1367          * ends at the end of the lowest committed fragment, or if there
 1368          * are no fragments, at the end of the highest committed block).
 1369          * Since files generally grow, the typical case is that the new
 1370          * block is to be added at the end of the list. We speed this
 1371          * special case by checking against the last allocdirect in the
 1372          * list before laboriously traversing the list looking for the
 1373          * insertion point.
 1374          */
 1375         adphead = &inodedep->id_newinoupdt;
 1376         oldadp = TAILQ_LAST(adphead, allocdirectlst);
 1377         if (oldadp == NULL || oldadp->ad_lbn <= lbn) {
 1378                 /* insert at end of list */
 1379                 TAILQ_INSERT_TAIL(adphead, adp, ad_next);
 1380                 if (oldadp != NULL && oldadp->ad_lbn == lbn)
 1381                         allocdirect_merge(adphead, adp, oldadp);
 1382                 FREE_LOCK(&lk);
 1383                 return;
 1384         }
 1385         TAILQ_FOREACH(oldadp, adphead, ad_next) {
 1386                 if (oldadp->ad_lbn >= lbn)
 1387                         break;
 1388         }
 1389         if (oldadp == NULL) {
 1390                 FREE_LOCK(&lk);
 1391                 panic("softdep_setup_allocdirect: lost entry");
 1392         }
 1393         /* insert in middle of list */
 1394         TAILQ_INSERT_BEFORE(oldadp, adp, ad_next);
 1395         if (oldadp->ad_lbn == lbn)
 1396                 allocdirect_merge(adphead, adp, oldadp);
 1397         FREE_LOCK(&lk);
 1398 }
 1399 
 1400 /*
 1401  * Replace an old allocdirect dependency with a newer one.
 1402  * This routine must be called with splbio interrupts blocked.
 1403  */
 1404 static void
 1405 allocdirect_merge(adphead, newadp, oldadp)
 1406         struct allocdirectlst *adphead; /* head of list holding allocdirects */
 1407         struct allocdirect *newadp;     /* allocdirect being added */
 1408         struct allocdirect *oldadp;     /* existing allocdirect being checked */
 1409 {
 1410         struct freefrag *freefrag;
 1411 
 1412 #ifdef DEBUG
 1413         if (lk.lkt_held == -1)
 1414                 panic("allocdirect_merge: lock not held");
 1415 #endif
 1416         if (newadp->ad_oldblkno != oldadp->ad_newblkno ||
 1417             newadp->ad_oldsize != oldadp->ad_newsize ||
 1418             newadp->ad_lbn >= NDADDR) {
 1419                 FREE_LOCK(&lk);
 1420                 panic("allocdirect_check: old %d != new %d || lbn %ld >= %d",
 1421                     newadp->ad_oldblkno, oldadp->ad_newblkno, newadp->ad_lbn,
 1422                     NDADDR);
 1423         }
 1424         newadp->ad_oldblkno = oldadp->ad_oldblkno;
 1425         newadp->ad_oldsize = oldadp->ad_oldsize;
 1426         /*
 1427          * If the old dependency had a fragment to free or had never
 1428          * previously had a block allocated, then the new dependency
 1429          * can immediately post its freefrag and adopt the old freefrag.
 1430          * This action is done by swapping the freefrag dependencies.
 1431          * The new dependency gains the old one's freefrag, and the
 1432          * old one gets the new one and then immediately puts it on
 1433          * the worklist when it is freed by free_allocdirect. It is
 1434          * not possible to do this swap when the old dependency had a
 1435          * non-zero size but no previous fragment to free. This condition
 1436          * arises when the new block is an extension of the old block.
 1437          * Here, the first part of the fragment allocated to the new
 1438          * dependency is part of the block currently claimed on disk by
 1439          * the old dependency, so cannot legitimately be freed until the
 1440          * conditions for the new dependency are fulfilled.
 1441          */
 1442         if (oldadp->ad_freefrag != NULL || oldadp->ad_oldblkno == 0) {
 1443                 freefrag = newadp->ad_freefrag;
 1444                 newadp->ad_freefrag = oldadp->ad_freefrag;
 1445                 oldadp->ad_freefrag = freefrag;
 1446         }
 1447         free_allocdirect(adphead, oldadp, 0);
 1448 }
 1449                 
 1450 /*
 1451  * Allocate a new freefrag structure if needed.
 1452  */
 1453 static struct freefrag *
 1454 newfreefrag(ip, blkno, size)
 1455         struct inode *ip;
 1456         ufs_daddr_t blkno;
 1457         long size;
 1458 {
 1459         struct freefrag *freefrag;
 1460         struct fs *fs;
 1461 
 1462         if (blkno == 0)
 1463                 return (NULL);
 1464         fs = ip->i_fs;
 1465         if (fragnum(fs, blkno) + numfrags(fs, size) > fs->fs_frag)
 1466                 panic("newfreefrag: frag size");
 1467         MALLOC(freefrag, struct freefrag *, sizeof(struct freefrag),
 1468                 M_FREEFRAG, M_SOFTDEP_FLAGS);
 1469         freefrag->ff_list.wk_type = D_FREEFRAG;
 1470         freefrag->ff_state = ip->i_uid & ~ONWORKLIST;   /* XXX - used below */
 1471         freefrag->ff_inum = ip->i_number;
 1472         freefrag->ff_fs = fs;
 1473         freefrag->ff_devvp = ip->i_devvp;
 1474         freefrag->ff_blkno = blkno;
 1475         freefrag->ff_fragsize = size;
 1476         return (freefrag);
 1477 }
 1478 
 1479 /*
 1480  * This workitem de-allocates fragments that were replaced during
 1481  * file block allocation.
 1482  */
 1483 static void 
 1484 handle_workitem_freefrag(freefrag)
 1485         struct freefrag *freefrag;
 1486 {
 1487         struct inode tip;
 1488 
 1489         tip.i_fs = freefrag->ff_fs;
 1490         tip.i_devvp = freefrag->ff_devvp;
 1491         tip.i_dev = freefrag->ff_devvp->v_rdev;
 1492         tip.i_number = freefrag->ff_inum;
 1493         tip.i_uid = freefrag->ff_state & ~ONWORKLIST;   /* XXX - set above */
 1494         ffs_blkfree(&tip, freefrag->ff_blkno, freefrag->ff_fragsize);
 1495         FREE(freefrag, M_FREEFRAG);
 1496 }
 1497 
 1498 /*
 1499  * Indirect block allocation dependencies.
 1500  * 
 1501  * The same dependencies that exist for a direct block also exist when
 1502  * a new block is allocated and pointed to by an entry in a block of
 1503  * indirect pointers. The undo/redo states described above are also
 1504  * used here. Because an indirect block contains many pointers that
 1505  * may have dependencies, a second copy of the entire in-memory indirect
 1506  * block is kept. The buffer cache copy is always completely up-to-date.
 1507  * The second copy, which is used only as a source for disk writes,
 1508  * contains only the safe pointers (i.e., those that have no remaining
 1509  * update dependencies). The second copy is freed when all pointers
 1510  * are safe. The cache is not allowed to replace indirect blocks with
 1511  * pending update dependencies. If a buffer containing an indirect
 1512  * block with dependencies is written, these routines will mark it
 1513  * dirty again. It can only be successfully written once all the
 1514  * dependencies are removed. The ffs_fsync routine in conjunction with
 1515  * softdep_sync_metadata work together to get all the dependencies
 1516  * removed so that a file can be successfully written to disk. Three
 1517  * procedures are used when setting up indirect block pointer
 1518  * dependencies. The division is necessary because of the organization
 1519  * of the "balloc" routine and because of the distinction between file
 1520  * pages and file metadata blocks.
 1521  */
 1522 
 1523 /*
 1524  * Allocate a new allocindir structure.
 1525  */
 1526 static struct allocindir *
 1527 newallocindir(ip, ptrno, newblkno, oldblkno)
 1528         struct inode *ip;       /* inode for file being extended */
 1529         int ptrno;              /* offset of pointer in indirect block */
 1530         ufs_daddr_t newblkno;   /* disk block number being added */
 1531         ufs_daddr_t oldblkno;   /* previous block number, 0 if none */
 1532 {
 1533         struct allocindir *aip;
 1534 
 1535         MALLOC(aip, struct allocindir *, sizeof(struct allocindir),
 1536                 M_ALLOCINDIR, M_SOFTDEP_FLAGS);
 1537         bzero(aip, sizeof(struct allocindir));
 1538         aip->ai_list.wk_type = D_ALLOCINDIR;
 1539         aip->ai_state = ATTACHED;
 1540         aip->ai_offset = ptrno;
 1541         aip->ai_newblkno = newblkno;
 1542         aip->ai_oldblkno = oldblkno;
 1543         aip->ai_freefrag = newfreefrag(ip, oldblkno, ip->i_fs->fs_bsize);
 1544         return (aip);
 1545 }
 1546 
 1547 /*
 1548  * Called just before setting an indirect block pointer
 1549  * to a newly allocated file page.
 1550  */
 1551 void
 1552 softdep_setup_allocindir_page(ip, lbn, bp, ptrno, newblkno, oldblkno, nbp)
 1553         struct inode *ip;       /* inode for file being extended */
 1554         ufs_lbn_t lbn;          /* allocated block number within file */
 1555         struct buf *bp;         /* buffer with indirect blk referencing page */
 1556         int ptrno;              /* offset of pointer in indirect block */
 1557         ufs_daddr_t newblkno;   /* disk block number being added */
 1558         ufs_daddr_t oldblkno;   /* previous block number, 0 if none */
 1559         struct buf *nbp;        /* buffer holding allocated page */
 1560 {
 1561         struct allocindir *aip;
 1562         struct pagedep *pagedep;
 1563 
 1564         aip = newallocindir(ip, ptrno, newblkno, oldblkno);
 1565         ACQUIRE_LOCK(&lk);
 1566         /*
 1567          * If we are allocating a directory page, then we must
 1568          * allocate an associated pagedep to track additions and
 1569          * deletions.
 1570          */
 1571         if ((ip->i_mode & IFMT) == IFDIR &&
 1572             pagedep_lookup(ip, lbn, DEPALLOC, &pagedep) == 0)
 1573                 WORKLIST_INSERT(&nbp->b_dep, &pagedep->pd_list);
 1574         WORKLIST_INSERT(&nbp->b_dep, &aip->ai_list);
 1575         FREE_LOCK(&lk);
 1576         setup_allocindir_phase2(bp, ip, aip);
 1577 }
 1578 
 1579 /*
 1580  * Called just before setting an indirect block pointer to a
 1581  * newly allocated indirect block.
 1582  */
 1583 void
 1584 softdep_setup_allocindir_meta(nbp, ip, bp, ptrno, newblkno)
 1585         struct buf *nbp;        /* newly allocated indirect block */
 1586         struct inode *ip;       /* inode for file being extended */
 1587         struct buf *bp;         /* indirect block referencing allocated block */
 1588         int ptrno;              /* offset of pointer in indirect block */
 1589         ufs_daddr_t newblkno;   /* disk block number being added */
 1590 {
 1591         struct allocindir *aip;
 1592 
 1593         aip = newallocindir(ip, ptrno, newblkno, 0);
 1594         ACQUIRE_LOCK(&lk);
 1595         WORKLIST_INSERT(&nbp->b_dep, &aip->ai_list);
 1596         FREE_LOCK(&lk);
 1597         setup_allocindir_phase2(bp, ip, aip);
 1598 }
 1599 
 1600 /*
 1601  * Called to finish the allocation of the "aip" allocated
 1602  * by one of the two routines above.
 1603  */
 1604 static void 
 1605 setup_allocindir_phase2(bp, ip, aip)
 1606         struct buf *bp;         /* in-memory copy of the indirect block */
 1607         struct inode *ip;       /* inode for file being extended */
 1608         struct allocindir *aip; /* allocindir allocated by the above routines */
 1609 {
 1610         struct worklist *wk;
 1611         struct indirdep *indirdep, *newindirdep;
 1612         struct bmsafemap *bmsafemap;
 1613         struct allocindir *oldaip;
 1614         struct freefrag *freefrag;
 1615         struct newblk *newblk;
 1616 
 1617         if (bp->b_lblkno >= 0)
 1618                 panic("setup_allocindir_phase2: not indir blk");
 1619         for (indirdep = NULL, newindirdep = NULL; ; ) {
 1620                 ACQUIRE_LOCK(&lk);
 1621                 LIST_FOREACH(wk, &bp->b_dep, wk_list) {
 1622                         if (wk->wk_type != D_INDIRDEP)
 1623                                 continue;
 1624                         indirdep = WK_INDIRDEP(wk);
 1625                         break;
 1626                 }
 1627                 if (indirdep == NULL && newindirdep) {
 1628                         indirdep = newindirdep;
 1629                         WORKLIST_INSERT(&bp->b_dep, &indirdep->ir_list);
 1630                         newindirdep = NULL;
 1631                 }
 1632                 FREE_LOCK(&lk);
 1633                 if (indirdep) {
 1634                         if (newblk_lookup(ip->i_fs, aip->ai_newblkno, 0,
 1635                             &newblk) == 0)
 1636                                 panic("setup_allocindir: lost block");
 1637                         ACQUIRE_LOCK(&lk);
 1638                         if (newblk->nb_state == DEPCOMPLETE) {
 1639                                 aip->ai_state |= DEPCOMPLETE;
 1640                                 aip->ai_buf = NULL;
 1641                         } else {
 1642                                 bmsafemap = newblk->nb_bmsafemap;
 1643                                 aip->ai_buf = bmsafemap->sm_buf;
 1644                                 LIST_REMOVE(newblk, nb_deps);
 1645                                 LIST_INSERT_HEAD(&bmsafemap->sm_allocindirhd,
 1646                                     aip, ai_deps);
 1647                         }
 1648                         LIST_REMOVE(newblk, nb_hash);
 1649                         FREE(newblk, M_NEWBLK);
 1650                         aip->ai_indirdep = indirdep;
 1651                         /*
 1652                          * Check to see if there is an existing dependency
 1653                          * for this block. If there is, merge the old
 1654                          * dependency into the new one.
 1655                          */
 1656                         if (aip->ai_oldblkno == 0)
 1657                                 oldaip = NULL;
 1658                         else
 1659 
 1660                                 LIST_FOREACH(oldaip, &indirdep->ir_deplisthd, ai_next)
 1661                                         if (oldaip->ai_offset == aip->ai_offset)
 1662                                                 break;
 1663                         if (oldaip != NULL) {
 1664                                 if (oldaip->ai_newblkno != aip->ai_oldblkno) {
 1665                                         FREE_LOCK(&lk);
 1666                                         panic("setup_allocindir_phase2: blkno");
 1667                                 }
 1668                                 aip->ai_oldblkno = oldaip->ai_oldblkno;
 1669                                 freefrag = oldaip->ai_freefrag;
 1670                                 oldaip->ai_freefrag = aip->ai_freefrag;
 1671                                 aip->ai_freefrag = freefrag;
 1672                                 free_allocindir(oldaip, NULL);
 1673                         }
 1674                         LIST_INSERT_HEAD(&indirdep->ir_deplisthd, aip, ai_next);
 1675                         ((ufs_daddr_t *)indirdep->ir_savebp->b_data)
 1676                             [aip->ai_offset] = aip->ai_oldblkno;
 1677                         FREE_LOCK(&lk);
 1678                 }
 1679                 if (newindirdep) {
 1680                         if (indirdep->ir_savebp != NULL)
 1681                                 brelse(newindirdep->ir_savebp);
 1682                         WORKITEM_FREE((caddr_t)newindirdep, D_INDIRDEP);
 1683                 }
 1684                 if (indirdep)
 1685                         break;
 1686                 MALLOC(newindirdep, struct indirdep *, sizeof(struct indirdep),
 1687                         M_INDIRDEP, M_SOFTDEP_FLAGS);
 1688                 newindirdep->ir_list.wk_type = D_INDIRDEP;
 1689                 newindirdep->ir_state = ATTACHED;
 1690                 LIST_INIT(&newindirdep->ir_deplisthd);
 1691                 LIST_INIT(&newindirdep->ir_donehd);
 1692                 if (bp->b_blkno == bp->b_lblkno) {
 1693                         VOP_BMAP(bp->b_vp, bp->b_lblkno, NULL, &bp->b_blkno,
 1694                                 NULL, NULL);
 1695                 }
 1696                 newindirdep->ir_savebp =
 1697                     getblk(ip->i_devvp, bp->b_blkno, bp->b_bcount, 0, 0);
 1698                 BUF_KERNPROC(newindirdep->ir_savebp);
 1699                 bcopy(bp->b_data, newindirdep->ir_savebp->b_data, bp->b_bcount);
 1700         }
 1701 }
 1702 
 1703 /*
 1704  * Block de-allocation dependencies.
 1705  * 
 1706  * When blocks are de-allocated, the on-disk pointers must be nullified before
 1707  * the blocks are made available for use by other files.  (The true
 1708  * requirement is that old pointers must be nullified before new on-disk
 1709  * pointers are set.  We chose this slightly more stringent requirement to
 1710  * reduce complexity.) Our implementation handles this dependency by updating
 1711  * the inode (or indirect block) appropriately but delaying the actual block
 1712  * de-allocation (i.e., freemap and free space count manipulation) until
 1713  * after the updated versions reach stable storage.  After the disk is
 1714  * updated, the blocks can be safely de-allocated whenever it is convenient.
 1715  * This implementation handles only the common case of reducing a file's
 1716  * length to zero. Other cases are handled by the conventional synchronous
 1717  * write approach.
 1718  *
 1719  * The ffs implementation with which we worked double-checks
 1720  * the state of the block pointers and file size as it reduces
 1721  * a file's length.  Some of this code is replicated here in our
 1722  * soft updates implementation.  The freeblks->fb_chkcnt field is
 1723  * used to transfer a part of this information to the procedure
 1724  * that eventually de-allocates the blocks.
 1725  *
 1726  * This routine should be called from the routine that shortens
 1727  * a file's length, before the inode's size or block pointers
 1728  * are modified. It will save the block pointer information for
 1729  * later release and zero the inode so that the calling routine
 1730  * can release it.
 1731  */
 1732 void
 1733 softdep_setup_freeblocks(ip, length)
 1734         struct inode *ip;       /* The inode whose length is to be reduced */
 1735         off_t length;           /* The new length for the file */
 1736 {
 1737         struct freeblks *freeblks;
 1738         struct inodedep *inodedep;
 1739         struct allocdirect *adp;
 1740         struct vnode *vp;
 1741         struct buf *bp;
 1742         struct fs *fs;
 1743         int i, error, delay;
 1744 
 1745         fs = ip->i_fs;
 1746         if (length != 0)
 1747                 panic("softde_setup_freeblocks: non-zero length");
 1748         MALLOC(freeblks, struct freeblks *, sizeof(struct freeblks),
 1749                 M_FREEBLKS, M_SOFTDEP_FLAGS);
 1750         bzero(freeblks, sizeof(struct freeblks));
 1751         freeblks->fb_list.wk_type = D_FREEBLKS;
 1752         freeblks->fb_state = ATTACHED;
 1753         freeblks->fb_uid = ip->i_uid;
 1754         freeblks->fb_previousinum = ip->i_number;
 1755         freeblks->fb_devvp = ip->i_devvp;
 1756         freeblks->fb_fs = fs;
 1757         freeblks->fb_oldsize = ip->i_size;
 1758         freeblks->fb_newsize = length;
 1759         freeblks->fb_chkcnt = ip->i_blocks;
 1760         for (i = 0; i < NDADDR; i++) {
 1761                 freeblks->fb_dblks[i] = ip->i_db[i];
 1762                 ip->i_db[i] = 0;
 1763         }
 1764         for (i = 0; i < NIADDR; i++) {
 1765                 freeblks->fb_iblks[i] = ip->i_ib[i];
 1766                 ip->i_ib[i] = 0;
 1767         }
 1768         ip->i_blocks = 0;
 1769         ip->i_size = 0;
 1770         /*
 1771          * Push the zero'ed inode to to its disk buffer so that we are free
 1772          * to delete its dependencies below. Once the dependencies are gone
 1773          * the buffer can be safely released.
 1774          */
 1775         if ((error = bread(ip->i_devvp,
 1776             fsbtodb(fs, ino_to_fsba(fs, ip->i_number)),
 1777             (int)fs->fs_bsize, NOCRED, &bp)) != 0)
 1778                 softdep_error("softdep_setup_freeblocks", error);
 1779         *((struct dinode *)bp->b_data + ino_to_fsbo(fs, ip->i_number)) =
 1780             ip->i_din;
 1781         /*
 1782          * Find and eliminate any inode dependencies.
 1783          */
 1784         ACQUIRE_LOCK(&lk);
 1785         (void) inodedep_lookup(fs, ip->i_number, DEPALLOC, &inodedep);
 1786         if ((inodedep->id_state & IOSTARTED) != 0) {
 1787                 FREE_LOCK(&lk);
 1788                 panic("softdep_setup_freeblocks: inode busy");
 1789         }
 1790         /*
 1791          * Add the freeblks structure to the list of operations that
 1792          * must await the zero'ed inode being written to disk. If we
 1793          * still have a bitmap dependency (delay == 0), then the inode
 1794          * has never been written to disk, so we can process the
 1795          * freeblks below once we have deleted the dependencies.
 1796          */
 1797         delay = (inodedep->id_state & DEPCOMPLETE);
 1798         if (delay)
 1799                 WORKLIST_INSERT(&inodedep->id_bufwait, &freeblks->fb_list);
 1800         /*
 1801          * Because the file length has been truncated to zero, any
 1802          * pending block allocation dependency structures associated
 1803          * with this inode are obsolete and can simply be de-allocated.
 1804          * We must first merge the two dependency lists to get rid of
 1805          * any duplicate freefrag structures, then purge the merged list.
 1806          */
 1807         merge_inode_lists(inodedep);
 1808         while ((adp = TAILQ_FIRST(&inodedep->id_inoupdt)) != 0)
 1809                 free_allocdirect(&inodedep->id_inoupdt, adp, 1);
 1810         FREE_LOCK(&lk);
 1811         bdwrite(bp);
 1812         /*
 1813          * We must wait for any I/O in progress to finish so that
 1814          * all potential buffers on the dirty list will be visible.
 1815          * Once they are all there, walk the list and get rid of
 1816          * any dependencies.
 1817          */
 1818         vp = ITOV(ip);
 1819         ACQUIRE_LOCK(&lk);
 1820         drain_output(vp, 1);
 1821         while (getdirtybuf(&TAILQ_FIRST(&vp->v_dirtyblkhd), MNT_WAIT)) {
 1822                 bp = TAILQ_FIRST(&vp->v_dirtyblkhd);
 1823                 (void) inodedep_lookup(fs, ip->i_number, 0, &inodedep);
 1824                 deallocate_dependencies(bp, inodedep);
 1825                 bp->b_flags |= B_INVAL | B_NOCACHE;
 1826                 FREE_LOCK(&lk);
 1827                 brelse(bp);
 1828                 ACQUIRE_LOCK(&lk);
 1829         }
 1830         if (inodedep_lookup(fs, ip->i_number, 0, &inodedep) != 0)
 1831                 (void)free_inodedep(inodedep);
 1832 
 1833         if(delay) {
 1834                 freeblks->fb_state |= DEPCOMPLETE;
 1835                 /*
 1836                  * If the inode with zeroed block pointers is now on disk
 1837                  * we can start freeing blocks. Add freeblks to the worklist
 1838                  * instead of calling  handle_workitem_freeblocks directly as
 1839                  * it is more likely that additional IO is needed to complete
 1840                  * the request here than in the !delay case.
 1841                  */  
 1842                 if ((freeblks->fb_state & ALLCOMPLETE) == ALLCOMPLETE)
 1843                         add_to_worklist(&freeblks->fb_list);
 1844         }
 1845 
 1846         FREE_LOCK(&lk);
 1847         /*
 1848          * If the inode has never been written to disk (delay == 0),
 1849          * then we can process the freeblks now that we have deleted
 1850          * the dependencies.
 1851          */
 1852         if (!delay)
 1853                 handle_workitem_freeblocks(freeblks);
 1854 }
 1855 
 1856 /*
 1857  * Reclaim any dependency structures from a buffer that is about to
 1858  * be reallocated to a new vnode. The buffer must be locked, thus,
 1859  * no I/O completion operations can occur while we are manipulating
 1860  * its associated dependencies. The mutex is held so that other I/O's
 1861  * associated with related dependencies do not occur.
 1862  */
 1863 static void
 1864 deallocate_dependencies(bp, inodedep)
 1865         struct buf *bp;
 1866         struct inodedep *inodedep;
 1867 {
 1868         struct worklist *wk;
 1869         struct indirdep *indirdep;
 1870         struct allocindir *aip;
 1871         struct pagedep *pagedep;
 1872         struct dirrem *dirrem;
 1873         struct diradd *dap;
 1874         int i;
 1875 
 1876         while ((wk = LIST_FIRST(&bp->b_dep)) != NULL) {
 1877                 switch (wk->wk_type) {
 1878 
 1879                 case D_INDIRDEP:
 1880                         indirdep = WK_INDIRDEP(wk);
 1881                         /*
 1882                          * None of the indirect pointers will ever be visible,
 1883                          * so they can simply be tossed. GOINGAWAY ensures
 1884                          * that allocated pointers will be saved in the buffer
 1885                          * cache until they are freed. Note that they will
 1886                          * only be able to be found by their physical address
 1887                          * since the inode mapping the logical address will
 1888                          * be gone. The save buffer used for the safe copy
 1889                          * was allocated in setup_allocindir_phase2 using
 1890                          * the physical address so it could be used for this
 1891                          * purpose. Hence we swap the safe copy with the real
 1892                          * copy, allowing the safe copy to be freed and holding
 1893                          * on to the real copy for later use in indir_trunc.
 1894                          */
 1895                         if (indirdep->ir_state & GOINGAWAY) {
 1896                                 FREE_LOCK(&lk);
 1897                                 panic("deallocate_dependencies: already gone");
 1898                         }
 1899                         indirdep->ir_state |= GOINGAWAY;
 1900                         while ((aip = LIST_FIRST(&indirdep->ir_deplisthd)) != 0)
 1901                                 free_allocindir(aip, inodedep);
 1902                         if (bp->b_lblkno >= 0 ||
 1903                             bp->b_blkno != indirdep->ir_savebp->b_lblkno) {
 1904                                 FREE_LOCK(&lk);
 1905                                 panic("deallocate_dependencies: not indir");
 1906                         }
 1907                         bcopy(bp->b_data, indirdep->ir_savebp->b_data,
 1908                             bp->b_bcount);
 1909                         WORKLIST_REMOVE(wk);
 1910                         WORKLIST_INSERT(&indirdep->ir_savebp->b_dep, wk);
 1911                         continue;
 1912 
 1913                 case D_PAGEDEP:
 1914                         pagedep = WK_PAGEDEP(wk);
 1915                         /*
 1916                          * None of the directory additions will ever be
 1917                          * visible, so they can simply be tossed.
 1918                          */
 1919                         for (i = 0; i < DAHASHSZ; i++)
 1920                                 while ((dap =
 1921                                     LIST_FIRST(&pagedep->pd_diraddhd[i])))
 1922                                         free_diradd(dap);
 1923                         while ((dap = LIST_FIRST(&pagedep->pd_pendinghd)) != 0)
 1924                                 free_diradd(dap);
 1925                         /*
 1926                          * Copy any directory remove dependencies to the list
 1927                          * to be processed after the zero'ed inode is written.
 1928                          * If the inode has already been written, then they 
 1929                          * can be dumped directly onto the work list.
 1930                          */
 1931                         LIST_FOREACH(dirrem, &pagedep->pd_dirremhd, dm_next) {
 1932                                 LIST_REMOVE(dirrem, dm_next);
 1933                                 dirrem->dm_dirinum = pagedep->pd_ino;
 1934                                 if (inodedep == NULL ||
 1935                                     (inodedep->id_state & ALLCOMPLETE) ==
 1936                                      ALLCOMPLETE)
 1937                                         add_to_worklist(&dirrem->dm_list);
 1938                                 else
 1939                                         WORKLIST_INSERT(&inodedep->id_bufwait,
 1940                                             &dirrem->dm_list);
 1941                         }
 1942                         WORKLIST_REMOVE(&pagedep->pd_list);
 1943                         LIST_REMOVE(pagedep, pd_hash);
 1944                         WORKITEM_FREE(pagedep, D_PAGEDEP);
 1945                         continue;
 1946 
 1947                 case D_ALLOCINDIR:
 1948                         free_allocindir(WK_ALLOCINDIR(wk), inodedep);
 1949                         continue;
 1950 
 1951                 case D_ALLOCDIRECT:
 1952                 case D_INODEDEP:
 1953                         FREE_LOCK(&lk);
 1954                         panic("deallocate_dependencies: Unexpected type %s",
 1955                             TYPENAME(wk->wk_type));
 1956                         /* NOTREACHED */
 1957 
 1958                 default:
 1959                         FREE_LOCK(&lk);
 1960                         panic("deallocate_dependencies: Unknown type %s",
 1961                             TYPENAME(wk->wk_type));
 1962                         /* NOTREACHED */
 1963                 }
 1964         }
 1965 }
 1966 
 1967 /*
 1968  * Free an allocdirect. Generate a new freefrag work request if appropriate.
 1969  * This routine must be called with splbio interrupts blocked.
 1970  */
 1971 static void
 1972 free_allocdirect(adphead, adp, delay)
 1973         struct allocdirectlst *adphead;
 1974         struct allocdirect *adp;
 1975         int delay;
 1976 {
 1977 
 1978 #ifdef DEBUG
 1979         if (lk.lkt_held == -1)
 1980                 panic("free_allocdirect: lock not held");
 1981 #endif
 1982         if ((adp->ad_state & DEPCOMPLETE) == 0)
 1983                 LIST_REMOVE(adp, ad_deps);
 1984         TAILQ_REMOVE(adphead, adp, ad_next);
 1985         if ((adp->ad_state & COMPLETE) == 0)
 1986                 WORKLIST_REMOVE(&adp->ad_list);
 1987         if (adp->ad_freefrag != NULL) {
 1988                 if (delay)
 1989                         WORKLIST_INSERT(&adp->ad_inodedep->id_bufwait,
 1990                             &adp->ad_freefrag->ff_list);
 1991                 else
 1992                         add_to_worklist(&adp->ad_freefrag->ff_list);
 1993         }
 1994         WORKITEM_FREE(adp, D_ALLOCDIRECT);
 1995 }
 1996 
 1997 /*
 1998  * Prepare an inode to be freed. The actual free operation is not
 1999  * done until the zero'ed inode has been written to disk.
 2000  */
 2001 void
 2002 softdep_freefile(pvp, ino, mode)
 2003                 struct vnode *pvp;
 2004                 ino_t ino;
 2005                 int mode;
 2006 {
 2007         struct inode *ip = VTOI(pvp);
 2008         struct inodedep *inodedep;
 2009         struct freefile *freefile;
 2010 
 2011         /*
 2012          * This sets up the inode de-allocation dependency.
 2013          */
 2014         MALLOC(freefile, struct freefile *, sizeof(struct freefile),
 2015                 M_FREEFILE, M_SOFTDEP_FLAGS);
 2016         freefile->fx_list.wk_type = D_FREEFILE;
 2017         freefile->fx_list.wk_state = 0;
 2018         freefile->fx_mode = mode;
 2019         freefile->fx_oldinum = ino;
 2020         freefile->fx_devvp = ip->i_devvp;
 2021         freefile->fx_fs = ip->i_fs;
 2022 
 2023         /*
 2024          * If the inodedep does not exist, then the zero'ed inode has
 2025          * been written to disk. If the allocated inode has never been
 2026          * written to disk, then the on-disk inode is zero'ed. In either
 2027          * case we can free the file immediately.
 2028          */
 2029         ACQUIRE_LOCK(&lk);
 2030         if (inodedep_lookup(ip->i_fs, ino, 0, &inodedep) == 0 ||
 2031             check_inode_unwritten(inodedep)) {
 2032                 FREE_LOCK(&lk);
 2033                 handle_workitem_freefile(freefile);
 2034                 return;
 2035         }
 2036         WORKLIST_INSERT(&inodedep->id_inowait, &freefile->fx_list);
 2037         FREE_LOCK(&lk);
 2038 }
 2039 
 2040 /*
 2041  * Check to see if an inode has never been written to disk. If
 2042  * so free the inodedep and return success, otherwise return failure.
 2043  * This routine must be called with splbio interrupts blocked.
 2044  *
 2045  * If we still have a bitmap dependency, then the inode has never
 2046  * been written to disk. Drop the dependency as it is no longer
 2047  * necessary since the inode is being deallocated. We set the
 2048  * ALLCOMPLETE flags since the bitmap now properly shows that the
 2049  * inode is not allocated. Even if the inode is actively being
 2050  * written, it has been rolled back to its zero'ed state, so we
 2051  * are ensured that a zero inode is what is on the disk. For short
 2052  * lived files, this change will usually result in removing all the
 2053  * dependencies from the inode so that it can be freed immediately.
 2054  */
 2055 static int
 2056 check_inode_unwritten(inodedep)
 2057         struct inodedep *inodedep;
 2058 {
 2059 
 2060         if ((inodedep->id_state & DEPCOMPLETE) != 0 ||
 2061             LIST_FIRST(&inodedep->id_pendinghd) != NULL ||
 2062             LIST_FIRST(&inodedep->id_bufwait) != NULL ||
 2063             LIST_FIRST(&inodedep->id_inowait) != NULL ||
 2064             TAILQ_FIRST(&inodedep->id_inoupdt) != NULL ||
 2065             TAILQ_FIRST(&inodedep->id_newinoupdt) != NULL ||
 2066             inodedep->id_nlinkdelta != 0)
 2067                 return (0);
 2068 
 2069         /*
 2070          * Another process might be in initiate_write_inodeblock
 2071          * trying to allocate memory without holding "Softdep Lock".
 2072          */
 2073         if ((inodedep->id_state & IOSTARTED) != 0 &&
 2074             inodedep->id_savedino == NULL)
 2075                 return (0);
 2076 
 2077         inodedep->id_state |= ALLCOMPLETE;
 2078         LIST_REMOVE(inodedep, id_deps);
 2079         inodedep->id_buf = NULL;
 2080         if (inodedep->id_state & ONWORKLIST)
 2081                 WORKLIST_REMOVE(&inodedep->id_list);
 2082         if (inodedep->id_savedino != NULL) {
 2083                 FREE(inodedep->id_savedino, M_INODEDEP);
 2084                 inodedep->id_savedino = NULL;
 2085         }
 2086         if (free_inodedep(inodedep) == 0) {
 2087                 FREE_LOCK(&lk);
 2088                 panic("check_inode_unwritten: busy inode");
 2089         }
 2090         return (1);
 2091 }
 2092 
 2093 /*
 2094  * Try to free an inodedep structure. Return 1 if it could be freed.
 2095  */
 2096 static int
 2097 free_inodedep(inodedep)
 2098         struct inodedep *inodedep;
 2099 {
 2100 
 2101         if ((inodedep->id_state & ONWORKLIST) != 0 ||
 2102             (inodedep->id_state & ALLCOMPLETE) != ALLCOMPLETE ||
 2103             LIST_FIRST(&inodedep->id_pendinghd) != NULL ||
 2104             LIST_FIRST(&inodedep->id_bufwait) != NULL ||
 2105             LIST_FIRST(&inodedep->id_inowait) != NULL ||
 2106             TAILQ_FIRST(&inodedep->id_inoupdt) != NULL ||
 2107             TAILQ_FIRST(&inodedep->id_newinoupdt) != NULL ||
 2108             inodedep->id_nlinkdelta != 0 || inodedep->id_savedino != NULL)
 2109                 return (0);
 2110         LIST_REMOVE(inodedep, id_hash);
 2111         WORKITEM_FREE(inodedep, D_INODEDEP);
 2112         num_inodedep -= 1;
 2113         return (1);
 2114 }
 2115 
 2116 /*
 2117  * This workitem routine performs the block de-allocation.
 2118  * The workitem is added to the pending list after the updated
 2119  * inode block has been written to disk.  As mentioned above,
 2120  * checks regarding the number of blocks de-allocated (compared
 2121  * to the number of blocks allocated for the file) are also
 2122  * performed in this function.
 2123  */
 2124 static void
 2125 handle_workitem_freeblocks(freeblks)
 2126         struct freeblks *freeblks;
 2127 {
 2128         struct inode tip;
 2129         ufs_daddr_t bn;
 2130         struct fs *fs;
 2131         int i, level, bsize;
 2132         long nblocks, blocksreleased = 0;
 2133         int error, allerror = 0;
 2134         ufs_lbn_t baselbns[NIADDR], tmpval;
 2135 
 2136         tip.i_number = freeblks->fb_previousinum;
 2137         tip.i_devvp = freeblks->fb_devvp;
 2138         tip.i_dev = freeblks->fb_devvp->v_rdev;
 2139         tip.i_fs = freeblks->fb_fs;
 2140         tip.i_size = freeblks->fb_oldsize;
 2141         tip.i_uid = freeblks->fb_uid;
 2142         fs = freeblks->fb_fs;
 2143         tmpval = 1;
 2144         baselbns[0] = NDADDR;
 2145         for (i = 1; i < NIADDR; i++) {
 2146                 tmpval *= NINDIR(fs);
 2147                 baselbns[i] = baselbns[i - 1] + tmpval;
 2148         }
 2149         nblocks = btodb(fs->fs_bsize);
 2150         blocksreleased = 0;
 2151         /*
 2152          * Indirect blocks first.
 2153          */
 2154         for (level = (NIADDR - 1); level >= 0; level--) {
 2155                 if ((bn = freeblks->fb_iblks[level]) == 0)
 2156                         continue;
 2157                 if ((error = indir_trunc(&tip, fsbtodb(fs, bn), level,
 2158                     baselbns[level], &blocksreleased)) == 0)
 2159                         allerror = error;
 2160                 ffs_blkfree(&tip, bn, fs->fs_bsize);
 2161                 blocksreleased += nblocks;
 2162         }
 2163         /*
 2164          * All direct blocks or frags.
 2165          */
 2166         for (i = (NDADDR - 1); i >= 0; i--) {
 2167                 if ((bn = freeblks->fb_dblks[i]) == 0)
 2168                         continue;
 2169                 bsize = blksize(fs, &tip, i);
 2170                 ffs_blkfree(&tip, bn, bsize);
 2171                 blocksreleased += btodb(bsize);
 2172         }
 2173 
 2174 #ifdef DIAGNOSTIC
 2175         if (freeblks->fb_chkcnt != blocksreleased)
 2176                 printf("handle_workitem_freeblocks: block count\n");
 2177         if (allerror)
 2178                 softdep_error("handle_workitem_freeblks", allerror);
 2179 #endif /* DIAGNOSTIC */
 2180         WORKITEM_FREE(freeblks, D_FREEBLKS);
 2181 }
 2182 
 2183 /*
 2184  * Release blocks associated with the inode ip and stored in the indirect
 2185  * block dbn. If level is greater than SINGLE, the block is an indirect block
 2186  * and recursive calls to indirtrunc must be used to cleanse other indirect
 2187  * blocks.
 2188  */
 2189 static int
 2190 indir_trunc(ip, dbn, level, lbn, countp)
 2191         struct inode *ip;
 2192         ufs_daddr_t dbn;
 2193         int level;
 2194         ufs_lbn_t lbn;
 2195         long *countp;
 2196 {
 2197         struct buf *bp;
 2198         ufs_daddr_t *bap;
 2199         ufs_daddr_t nb;
 2200         struct fs *fs;
 2201         struct worklist *wk;
 2202         struct indirdep *indirdep;
 2203         int i, lbnadd, nblocks;
 2204         int error, allerror = 0;
 2205 
 2206         fs = ip->i_fs;
 2207         lbnadd = 1;
 2208         for (i = level; i > 0; i--)
 2209                 lbnadd *= NINDIR(fs);
 2210         /*
 2211          * Get buffer of block pointers to be freed. This routine is not
 2212          * called until the zero'ed inode has been written, so it is safe
 2213          * to free blocks as they are encountered. Because the inode has
 2214          * been zero'ed, calls to bmap on these blocks will fail. So, we
 2215          * have to use the on-disk address and the block device for the
 2216          * filesystem to look them up. If the file was deleted before its
 2217          * indirect blocks were all written to disk, the routine that set
 2218          * us up (deallocate_dependencies) will have arranged to leave
 2219          * a complete copy of the indirect block in memory for our use.
 2220          * Otherwise we have to read the blocks in from the disk.
 2221          */
 2222         ACQUIRE_LOCK(&lk);
 2223         if ((bp = incore(ip->i_devvp, dbn)) != NULL &&
 2224             (wk = LIST_FIRST(&bp->b_dep)) != NULL) {
 2225                 if (wk->wk_type != D_INDIRDEP ||
 2226                     (indirdep = WK_INDIRDEP(wk))->ir_savebp != bp ||
 2227                     (indirdep->ir_state & GOINGAWAY) == 0) {
 2228                         FREE_LOCK(&lk);
 2229                         panic("indir_trunc: lost indirdep");
 2230                 }
 2231                 WORKLIST_REMOVE(wk);
 2232                 WORKITEM_FREE(indirdep, D_INDIRDEP);
 2233                 if (LIST_FIRST(&bp->b_dep) != NULL) {
 2234                         FREE_LOCK(&lk);
 2235                         panic("indir_trunc: dangling dep");
 2236                 }
 2237                 FREE_LOCK(&lk);
 2238         } else {
 2239                 FREE_LOCK(&lk);
 2240                 error = bread(ip->i_devvp, dbn, (int)fs->fs_bsize, NOCRED, &bp);
 2241                 if (error)
 2242                         return (error);
 2243         }
 2244         /*
 2245          * Recursively free indirect blocks.
 2246          */
 2247         bap = (ufs_daddr_t *)bp->b_data;
 2248         nblocks = btodb(fs->fs_bsize);
 2249         for (i = NINDIR(fs) - 1; i >= 0; i--) {
 2250                 if ((nb = bap[i]) == 0)
 2251                         continue;
 2252                 if (level != 0) {
 2253                         if ((error = indir_trunc(ip, fsbtodb(fs, nb),
 2254                              level - 1, lbn + (i * lbnadd), countp)) != 0)
 2255                                 allerror = error;
 2256                 }
 2257                 ffs_blkfree(ip, nb, fs->fs_bsize);
 2258                 *countp += nblocks;
 2259         }
 2260         bp->b_flags |= B_INVAL | B_NOCACHE;
 2261         brelse(bp);
 2262         return (allerror);
 2263 }
 2264 
 2265 /*
 2266  * Free an allocindir.
 2267  * This routine must be called with splbio interrupts blocked.
 2268  */
 2269 static void
 2270 free_allocindir(aip, inodedep)
 2271         struct allocindir *aip;
 2272         struct inodedep *inodedep;
 2273 {
 2274         struct freefrag *freefrag;
 2275 
 2276 #ifdef DEBUG
 2277         if (lk.lkt_held == -1)
 2278                 panic("free_allocindir: lock not held");
 2279 #endif
 2280         if ((aip->ai_state & DEPCOMPLETE) == 0)
 2281                 LIST_REMOVE(aip, ai_deps);
 2282         if (aip->ai_state & ONWORKLIST)
 2283                 WORKLIST_REMOVE(&aip->ai_list);
 2284         LIST_REMOVE(aip, ai_next);
 2285         if ((freefrag = aip->ai_freefrag) != NULL) {
 2286                 if (inodedep == NULL)
 2287                         add_to_worklist(&freefrag->ff_list);
 2288                 else
 2289                         WORKLIST_INSERT(&inodedep->id_bufwait,
 2290                             &freefrag->ff_list);
 2291         }
 2292         WORKITEM_FREE(aip, D_ALLOCINDIR);
 2293 }
 2294 
 2295 /*
 2296  * Directory entry addition dependencies.
 2297  * 
 2298  * When adding a new directory entry, the inode (with its incremented link
 2299  * count) must be written to disk before the directory entry's pointer to it.
 2300  * Also, if the inode is newly allocated, the corresponding freemap must be
 2301  * updated (on disk) before the directory entry's pointer. These requirements
 2302  * are met via undo/redo on the directory entry's pointer, which consists
 2303  * simply of the inode number.
 2304  * 
 2305  * As directory entries are added and deleted, the free space within a
 2306  * directory block can become fragmented.  The ufs file system will compact
 2307  * a fragmented directory block to make space for a new entry. When this
 2308  * occurs, the offsets of previously added entries change. Any "diradd"
 2309  * dependency structures corresponding to these entries must be updated with
 2310  * the new offsets.
 2311  */
 2312 
 2313 /*
 2314  * This routine is called after the in-memory inode's link
 2315  * count has been incremented, but before the directory entry's
 2316  * pointer to the inode has been set.
 2317  */
 2318 void 
 2319 softdep_setup_directory_add(bp, dp, diroffset, newinum, newdirbp)
 2320         struct buf *bp;         /* buffer containing directory block */
 2321         struct inode *dp;       /* inode for directory */
 2322         off_t diroffset;        /* offset of new entry in directory */
 2323         long newinum;           /* inode referenced by new directory entry */
 2324         struct buf *newdirbp;   /* non-NULL => contents of new mkdir */
 2325 {
 2326         int offset;             /* offset of new entry within directory block */
 2327         ufs_lbn_t lbn;          /* block in directory containing new entry */
 2328         struct fs *fs;
 2329         struct diradd *dap;
 2330         struct pagedep *pagedep;
 2331         struct inodedep *inodedep;
 2332         struct mkdir *mkdir1, *mkdir2;
 2333 
 2334         /*
 2335          * Whiteouts have no dependencies.
 2336          */
 2337         if (newinum == WINO) {
 2338                 if (newdirbp != NULL)
 2339                         bdwrite(newdirbp);
 2340                 return;
 2341         }
 2342 
 2343         fs = dp->i_fs;
 2344         lbn = lblkno(fs, diroffset);
 2345         offset = blkoff(fs, diroffset);
 2346         MALLOC(dap, struct diradd *, sizeof(struct diradd), M_DIRADD,
 2347             M_SOFTDEP_FLAGS);
 2348         bzero(dap, sizeof(struct diradd));
 2349         dap->da_list.wk_type = D_DIRADD;
 2350         dap->da_offset = offset;
 2351         dap->da_newinum = newinum;
 2352         dap->da_state = ATTACHED;
 2353         if (newdirbp == NULL) {
 2354                 dap->da_state |= DEPCOMPLETE;
 2355                 ACQUIRE_LOCK(&lk);
 2356         } else {
 2357                 dap->da_state |= MKDIR_BODY | MKDIR_PARENT;
 2358                 MALLOC(mkdir1, struct mkdir *, sizeof(struct mkdir), M_MKDIR,
 2359                     M_SOFTDEP_FLAGS);
 2360                 mkdir1->md_list.wk_type = D_MKDIR;
 2361                 mkdir1->md_state = MKDIR_BODY;
 2362                 mkdir1->md_diradd = dap;
 2363                 MALLOC(mkdir2, struct mkdir *, sizeof(struct mkdir), M_MKDIR,
 2364                     M_SOFTDEP_FLAGS);
 2365                 mkdir2->md_list.wk_type = D_MKDIR;
 2366                 mkdir2->md_state = MKDIR_PARENT;
 2367                 mkdir2->md_diradd = dap;
 2368                 /*
 2369                  * Dependency on "." and ".." being written to disk.
 2370                  */
 2371                 mkdir1->md_buf = newdirbp;
 2372                 ACQUIRE_LOCK(&lk);
 2373                 LIST_INSERT_HEAD(&mkdirlisthd, mkdir1, md_mkdirs);
 2374                 WORKLIST_INSERT(&newdirbp->b_dep, &mkdir1->md_list);
 2375                 FREE_LOCK(&lk);
 2376                 bdwrite(newdirbp);
 2377                 /*
 2378                  * Dependency on link count increase for parent directory
 2379                  */
 2380                 ACQUIRE_LOCK(&lk);
 2381                 if (inodedep_lookup(dp->i_fs, dp->i_number, 0, &inodedep) == 0
 2382                     || (inodedep->id_state & ALLCOMPLETE) == ALLCOMPLETE) {
 2383                         dap->da_state &= ~MKDIR_PARENT;
 2384                         WORKITEM_FREE(mkdir2, D_MKDIR);
 2385                 } else {
 2386                         LIST_INSERT_HEAD(&mkdirlisthd, mkdir2, md_mkdirs);
 2387                         WORKLIST_INSERT(&inodedep->id_bufwait,&mkdir2->md_list);
 2388                 }
 2389         }
 2390         /*
 2391          * Link into parent directory pagedep to await its being written.
 2392          */
 2393         if (pagedep_lookup(dp, lbn, DEPALLOC, &pagedep) == 0)
 2394                 WORKLIST_INSERT(&bp->b_dep, &pagedep->pd_list);
 2395         dap->da_pagedep = pagedep;
 2396         LIST_INSERT_HEAD(&pagedep->pd_diraddhd[DIRADDHASH(offset)], dap,
 2397             da_pdlist);
 2398         /*
 2399          * Link into its inodedep. Put it on the id_bufwait list if the inode
 2400          * is not yet written. If it is written, do the post-inode write
 2401          * processing to put it on the id_pendinghd list.
 2402          */
 2403         (void) inodedep_lookup(fs, newinum, DEPALLOC, &inodedep);
 2404         if ((inodedep->id_state & ALLCOMPLETE) == ALLCOMPLETE)
 2405                 diradd_inode_written(dap, inodedep);
 2406         else
 2407                 WORKLIST_INSERT(&inodedep->id_bufwait, &dap->da_list);
 2408         FREE_LOCK(&lk);
 2409 }
 2410 
 2411 /*
 2412  * This procedure is called to change the offset of a directory
 2413  * entry when compacting a directory block which must be owned
 2414  * exclusively by the caller. Note that the actual entry movement
 2415  * must be done in this procedure to ensure that no I/O completions
 2416  * occur while the move is in progress.
 2417  */
 2418 void 
 2419 softdep_change_directoryentry_offset(dp, base, oldloc, newloc, entrysize)
 2420         struct inode *dp;       /* inode for directory */
 2421         caddr_t base;           /* address of dp->i_offset */
 2422         caddr_t oldloc;         /* address of old directory location */
 2423         caddr_t newloc;         /* address of new directory location */
 2424         int entrysize;          /* size of directory entry */
 2425 {
 2426         int offset, oldoffset, newoffset;
 2427         struct pagedep *pagedep;
 2428         struct diradd *dap;
 2429         ufs_lbn_t lbn;
 2430 
 2431         ACQUIRE_LOCK(&lk);
 2432         lbn = lblkno(dp->i_fs, dp->i_offset);
 2433         offset = blkoff(dp->i_fs, dp->i_offset);
 2434         if (pagedep_lookup(dp, lbn, 0, &pagedep) == 0)
 2435                 goto done;
 2436         oldoffset = offset + (oldloc - base);
 2437         newoffset = offset + (newloc - base);
 2438 
 2439         LIST_FOREACH(dap, &pagedep->pd_diraddhd[DIRADDHASH(oldoffset)], da_pdlist) {
 2440                 if (dap->da_offset != oldoffset)
 2441                         continue;
 2442                 dap->da_offset = newoffset;
 2443                 if (DIRADDHASH(newoffset) == DIRADDHASH(oldoffset))
 2444                         break;
 2445                 LIST_REMOVE(dap, da_pdlist);
 2446                 LIST_INSERT_HEAD(&pagedep->pd_diraddhd[DIRADDHASH(newoffset)],
 2447                     dap, da_pdlist);
 2448                 break;
 2449         }
 2450         if (dap == NULL) {
 2451 
 2452                 LIST_FOREACH(dap, &pagedep->pd_pendinghd, da_pdlist) {
 2453                         if (dap->da_offset == oldoffset) {
 2454                                 dap->da_offset = newoffset;
 2455                                 break;
 2456                         }
 2457                 }
 2458         }
 2459 done:
 2460         bcopy(oldloc, newloc, entrysize);
 2461         FREE_LOCK(&lk);
 2462 }
 2463 
 2464 /*
 2465  * Free a diradd dependency structure. This routine must be called
 2466  * with splbio interrupts blocked.
 2467  */
 2468 static void
 2469 free_diradd(dap)
 2470         struct diradd *dap;
 2471 {
 2472         struct dirrem *dirrem;
 2473         struct pagedep *pagedep;
 2474         struct inodedep *inodedep;
 2475         struct mkdir *mkdir, *nextmd;
 2476 
 2477 #ifdef DEBUG
 2478         if (lk.lkt_held == -1)
 2479                 panic("free_diradd: lock not held");
 2480 #endif
 2481         WORKLIST_REMOVE(&dap->da_list);
 2482         LIST_REMOVE(dap, da_pdlist);
 2483         if ((dap->da_state & DIRCHG) == 0) {
 2484                 pagedep = dap->da_pagedep;
 2485         } else {
 2486                 dirrem = dap->da_previous;
 2487                 pagedep = dirrem->dm_pagedep;
 2488                 dirrem->dm_dirinum = pagedep->pd_ino;
 2489                 add_to_worklist(&dirrem->dm_list);
 2490         }
 2491         if (inodedep_lookup(VFSTOUFS(pagedep->pd_mnt)->um_fs, dap->da_newinum,
 2492             0, &inodedep) != 0)
 2493                 (void) free_inodedep(inodedep);
 2494         if ((dap->da_state & (MKDIR_PARENT | MKDIR_BODY)) != 0) {
 2495                 for (mkdir = LIST_FIRST(&mkdirlisthd); mkdir; mkdir = nextmd) {
 2496                         nextmd = LIST_NEXT(mkdir, md_mkdirs);
 2497                         if (mkdir->md_diradd != dap)
 2498                                 continue;
 2499                         dap->da_state &= ~mkdir->md_state;
 2500                         WORKLIST_REMOVE(&mkdir->md_list);
 2501                         LIST_REMOVE(mkdir, md_mkdirs);
 2502                         WORKITEM_FREE(mkdir, D_MKDIR);
 2503                 }
 2504                 if ((dap->da_state & (MKDIR_PARENT | MKDIR_BODY)) != 0) {
 2505                         FREE_LOCK(&lk);
 2506                         panic("free_diradd: unfound ref");
 2507                 }
 2508         }
 2509         WORKITEM_FREE(dap, D_DIRADD);
 2510 }
 2511 
 2512 /*
 2513  * Directory entry removal dependencies.
 2514  * 
 2515  * When removing a directory entry, the entry's inode pointer must be
 2516  * zero'ed on disk before the corresponding inode's link count is decremented
 2517  * (possibly freeing the inode for re-use). This dependency is handled by
 2518  * updating the directory entry but delaying the inode count reduction until
 2519  * after the directory block has been written to disk. After this point, the
 2520  * inode count can be decremented whenever it is convenient.
 2521  */
 2522 
 2523 /*
 2524  * This routine should be called immediately after removing
 2525  * a directory entry.  The inode's link count should not be
 2526  * decremented by the calling procedure -- the soft updates
 2527  * code will do this task when it is safe.
 2528  */
 2529 void 
 2530 softdep_setup_remove(bp, dp, ip, isrmdir)
 2531         struct buf *bp;         /* buffer containing directory block */
 2532         struct inode *dp;       /* inode for the directory being modified */
 2533         struct inode *ip;       /* inode for directory entry being removed */
 2534         int isrmdir;            /* indicates if doing RMDIR */
 2535 {
 2536         struct dirrem *dirrem, *prevdirrem;
 2537 
 2538         /*
 2539          * Allocate a new dirrem if appropriate and ACQUIRE_LOCK.
 2540          */
 2541         dirrem = newdirrem(bp, dp, ip, isrmdir, &prevdirrem);
 2542 
 2543         /*
 2544          * If the COMPLETE flag is clear, then there were no active
 2545          * entries and we want to roll back to a zeroed entry until
 2546          * the new inode is committed to disk. If the COMPLETE flag is
 2547          * set then we have deleted an entry that never made it to
 2548          * disk. If the entry we deleted resulted from a name change,
 2549          * then the old name still resides on disk. We cannot delete
 2550          * its inode (returned to us in prevdirrem) until the zeroed
 2551          * directory entry gets to disk. The new inode has never been
 2552          * referenced on the disk, so can be deleted immediately.
 2553          */
 2554         if ((dirrem->dm_state & COMPLETE) == 0) {
 2555                 LIST_INSERT_HEAD(&dirrem->dm_pagedep->pd_dirremhd, dirrem,
 2556                     dm_next);
 2557                 FREE_LOCK(&lk);
 2558         } else {
 2559                 if (prevdirrem != NULL)
 2560                         LIST_INSERT_HEAD(&dirrem->dm_pagedep->pd_dirremhd,
 2561                             prevdirrem, dm_next);
 2562                 dirrem->dm_dirinum = dirrem->dm_pagedep->pd_ino;
 2563                 FREE_LOCK(&lk);
 2564                 handle_workitem_remove(dirrem);
 2565         }
 2566 }
 2567 
 2568 /*
 2569  * Allocate a new dirrem if appropriate and return it along with
 2570  * its associated pagedep. Called without a lock, returns with lock.
 2571  */
 2572 static long num_dirrem;         /* number of dirrem allocated */
 2573 static struct dirrem *
 2574 newdirrem(bp, dp, ip, isrmdir, prevdirremp)
 2575         struct buf *bp;         /* buffer containing directory block */
 2576         struct inode *dp;       /* inode for the directory being modified */
 2577         struct inode *ip;       /* inode for directory entry being removed */
 2578         int isrmdir;            /* indicates if doing RMDIR */
 2579         struct dirrem **prevdirremp; /* previously referenced inode, if any */
 2580 {
 2581         int offset;
 2582         ufs_lbn_t lbn;
 2583         struct diradd *dap;
 2584         struct dirrem *dirrem;
 2585         struct pagedep *pagedep;
 2586 
 2587         /*
 2588          * Whiteouts have no deletion dependencies.
 2589          */
 2590         if (ip == NULL)
 2591                 panic("newdirrem: whiteout");
 2592         /*
 2593          * If we are over our limit, try to improve the situation.
 2594          * Limiting the number of dirrem structures will also limit
 2595          * the number of freefile and freeblks structures.
 2596          */
 2597         if (num_dirrem > max_softdeps / 2 && speedup_syncer() == 0)
 2598                 (void) request_cleanup(FLUSH_REMOVE, 0);
 2599         num_dirrem += 1;
 2600         MALLOC(dirrem, struct dirrem *, sizeof(struct dirrem),
 2601                 M_DIRREM, M_SOFTDEP_FLAGS);
 2602         bzero(dirrem, sizeof(struct dirrem));
 2603         dirrem->dm_list.wk_type = D_DIRREM;
 2604         dirrem->dm_state = isrmdir ? RMDIR : 0;
 2605         dirrem->dm_mnt = ITOV(ip)->v_mount;
 2606         dirrem->dm_oldinum = ip->i_number;
 2607         *prevdirremp = NULL;
 2608 
 2609         ACQUIRE_LOCK(&lk);
 2610         lbn = lblkno(dp->i_fs, dp->i_offset);
 2611         offset = blkoff(dp->i_fs, dp->i_offset);
 2612         if (pagedep_lookup(dp, lbn, DEPALLOC, &pagedep) == 0)
 2613                 WORKLIST_INSERT(&bp->b_dep, &pagedep->pd_list);
 2614         dirrem->dm_pagedep = pagedep;
 2615         /*
 2616          * Check for a diradd dependency for the same directory entry.
 2617          * If present, then both dependencies become obsolete and can
 2618          * be de-allocated. Check for an entry on both the pd_dirraddhd
 2619          * list and the pd_pendinghd list.
 2620          */
 2621 
 2622         LIST_FOREACH(dap, &pagedep->pd_diraddhd[DIRADDHASH(offset)], da_pdlist)
 2623                 if (dap->da_offset == offset)
 2624                         break;
 2625         if (dap == NULL) {
 2626 
 2627                 LIST_FOREACH(dap, &pagedep->pd_pendinghd, da_pdlist)
 2628                         if (dap->da_offset == offset)
 2629                                 break;
 2630                 if (dap == NULL)
 2631                         return (dirrem);
 2632         }
 2633         /*
 2634          * Must be ATTACHED at this point.
 2635          */
 2636         if ((dap->da_state & ATTACHED) == 0) {
 2637                 FREE_LOCK(&lk);
 2638                 panic("newdirrem: not ATTACHED");
 2639         }
 2640         if (dap->da_newinum != ip->i_number) {
 2641                 FREE_LOCK(&lk);
 2642                 panic("newdirrem: inum %d should be %d",
 2643                     ip->i_number, dap->da_newinum);
 2644         }
 2645         /*
 2646          * If we are deleting a changed name that never made it to disk,
 2647          * then return the dirrem describing the previous inode (which
 2648          * represents the inode currently referenced from this entry on disk).
 2649          */
 2650         if ((dap->da_state & DIRCHG) != 0) {
 2651                 *prevdirremp = dap->da_previous;
 2652                 dap->da_state &= ~DIRCHG;
 2653                 dap->da_pagedep = pagedep;
 2654         }
 2655         /*
 2656          * We are deleting an entry that never made it to disk.
 2657          * Mark it COMPLETE so we can delete its inode immediately.
 2658          */
 2659         dirrem->dm_state |= COMPLETE;
 2660         free_diradd(dap);
 2661         return (dirrem);
 2662 }
 2663 
 2664 /*
 2665  * Directory entry change dependencies.
 2666  * 
 2667  * Changing an existing directory entry requires that an add operation
 2668  * be completed first followed by a deletion. The semantics for the addition
 2669  * are identical to the description of adding a new entry above except
 2670  * that the rollback is to the old inode number rather than zero. Once
 2671  * the addition dependency is completed, the removal is done as described
 2672  * in the removal routine above.
 2673  */
 2674 
 2675 /*
 2676  * This routine should be called immediately after changing
 2677  * a directory entry.  The inode's link count should not be
 2678  * decremented by the calling procedure -- the soft updates
 2679  * code will perform this task when it is safe.
 2680  */
 2681 void 
 2682 softdep_setup_directory_change(bp, dp, ip, newinum, isrmdir)
 2683         struct buf *bp;         /* buffer containing directory block */
 2684         struct inode *dp;       /* inode for the directory being modified */
 2685         struct inode *ip;       /* inode for directory entry being removed */
 2686         long newinum;           /* new inode number for changed entry */
 2687         int isrmdir;            /* indicates if doing RMDIR */
 2688 {
 2689         int offset;
 2690         struct diradd *dap = NULL;
 2691         struct dirrem *dirrem, *prevdirrem;
 2692         struct pagedep *pagedep;
 2693         struct inodedep *inodedep;
 2694 
 2695         offset = blkoff(dp->i_fs, dp->i_offset);
 2696 
 2697         /*
 2698          * Whiteouts do not need diradd dependencies.
 2699          */
 2700         if (newinum != WINO) {
 2701                 MALLOC(dap, struct diradd *, sizeof(struct diradd),
 2702                     M_DIRADD, M_SOFTDEP_FLAGS);
 2703                 bzero(dap, sizeof(struct diradd));
 2704                 dap->da_list.wk_type = D_DIRADD;
 2705                 dap->da_state = DIRCHG | ATTACHED | DEPCOMPLETE;
 2706                 dap->da_offset = offset;
 2707                 dap->da_newinum = newinum;
 2708         }
 2709 
 2710         /*
 2711          * Allocate a new dirrem and ACQUIRE_LOCK.
 2712          */
 2713         dirrem = newdirrem(bp, dp, ip, isrmdir, &prevdirrem);
 2714         pagedep = dirrem->dm_pagedep;
 2715         /*
 2716          * The possible values for isrmdir:
 2717          *      0 - non-directory file rename
 2718          *      1 - directory rename within same directory
 2719          *   inum - directory rename to new directory of given inode number
 2720          * When renaming to a new directory, we are both deleting and
 2721          * creating a new directory entry, so the link count on the new
 2722          * directory should not change. Thus we do not need the followup
 2723          * dirrem which is usually done in handle_workitem_remove. We set
 2724          * the DIRCHG flag to tell handle_workitem_remove to skip the 
 2725          * followup dirrem.
 2726          */
 2727         if (isrmdir > 1)
 2728                 dirrem->dm_state |= DIRCHG;
 2729 
 2730         /*
 2731          * Whiteouts have no additional dependencies,
 2732          * so just put the dirrem on the correct list.
 2733          */
 2734         if (newinum == WINO) {
 2735                 if ((dirrem->dm_state & COMPLETE) == 0) {
 2736                         LIST_INSERT_HEAD(&pagedep->pd_dirremhd, dirrem,
 2737                             dm_next);
 2738                 } else {
 2739                         dirrem->dm_dirinum = pagedep->pd_ino;
 2740                         add_to_worklist(&dirrem->dm_list);
 2741                 }
 2742                 FREE_LOCK(&lk);
 2743                 return;
 2744         }
 2745 
 2746         /*
 2747          * If the COMPLETE flag is clear, then there were no active
 2748          * entries and we want to roll back to the previous inode until
 2749          * the new inode is committed to disk. If the COMPLETE flag is
 2750          * set, then we have deleted an entry that never made it to disk.
 2751          * If the entry we deleted resulted from a name change, then the old
 2752          * inode reference still resides on disk. Any rollback that we do
 2753          * needs to be to that old inode (returned to us in prevdirrem). If
 2754          * the entry we deleted resulted from a create, then there is
 2755          * no entry on the disk, so we want to roll back to zero rather
 2756          * than the uncommitted inode. In either of the COMPLETE cases we
 2757          * want to immediately free the unwritten and unreferenced inode.
 2758          */
 2759         if ((dirrem->dm_state & COMPLETE) == 0) {
 2760                 dap->da_previous = dirrem;
 2761         } else {
 2762                 if (prevdirrem != NULL) {
 2763                         dap->da_previous = prevdirrem;
 2764                 } else {
 2765                         dap->da_state &= ~DIRCHG;
 2766                         dap->da_pagedep = pagedep;
 2767                 }
 2768                 dirrem->dm_dirinum = pagedep->pd_ino;
 2769                 add_to_worklist(&dirrem->dm_list);
 2770         }
 2771         /*
 2772          * Link into its inodedep. Put it on the id_bufwait list if the inode
 2773          * is not yet written. If it is written, do the post-inode write
 2774          * processing to put it on the id_pendinghd list.
 2775          */
 2776         if (inodedep_lookup(dp->i_fs, newinum, DEPALLOC, &inodedep) == 0 ||
 2777             (inodedep->id_state & ALLCOMPLETE) == ALLCOMPLETE) {
 2778                 dap->da_state |= COMPLETE;
 2779                 LIST_INSERT_HEAD(&pagedep->pd_pendinghd, dap, da_pdlist);
 2780                 WORKLIST_INSERT(&inodedep->id_pendinghd, &dap->da_list);
 2781         } else {
 2782                 LIST_INSERT_HEAD(&pagedep->pd_diraddhd[DIRADDHASH(offset)],
 2783                     dap, da_pdlist);
 2784                 WORKLIST_INSERT(&inodedep->id_bufwait, &dap->da_list);
 2785         }
 2786         FREE_LOCK(&lk);
 2787 }
 2788 
 2789 /*
 2790  * Called whenever the link count on an inode is changed.
 2791  * It creates an inode dependency so that the new reference(s)
 2792  * to the inode cannot be committed to disk until the updated
 2793  * inode has been written.
 2794  */
 2795 void
 2796 softdep_change_linkcnt(ip)
 2797         struct inode *ip;       /* the inode with the increased link count */
 2798 {
 2799         struct inodedep *inodedep;
 2800 
 2801         ACQUIRE_LOCK(&lk);
 2802         (void) inodedep_lookup(ip->i_fs, ip->i_number, DEPALLOC, &inodedep);
 2803         if (ip->i_nlink < ip->i_effnlink) {
 2804                 FREE_LOCK(&lk);
 2805                 panic("softdep_change_linkcnt: bad delta");
 2806         }
 2807         inodedep->id_nlinkdelta = ip->i_nlink - ip->i_effnlink;
 2808         FREE_LOCK(&lk);
 2809 }
 2810 
 2811 /*
 2812  * This workitem decrements the inode's link count.
 2813  * If the link count reaches zero, the file is removed.
 2814  */
 2815 static void 
 2816 handle_workitem_remove(dirrem)
 2817         struct dirrem *dirrem;
 2818 {
 2819         struct proc *p = CURPROC;       /* XXX */
 2820         struct inodedep *inodedep;
 2821         struct vnode *vp;
 2822         struct inode *ip;
 2823         ino_t oldinum;
 2824         int error;
 2825 
 2826         if ((error = VFS_VGET(dirrem->dm_mnt, dirrem->dm_oldinum, &vp)) != 0) {
 2827                 softdep_error("handle_workitem_remove: vget", error);
 2828                 return;
 2829         }
 2830         ip = VTOI(vp);
 2831         ACQUIRE_LOCK(&lk);
 2832         if ((inodedep_lookup(ip->i_fs, dirrem->dm_oldinum, 0, &inodedep)) == 0){
 2833                 FREE_LOCK(&lk);
 2834                 panic("handle_workitem_remove: lost inodedep");
 2835         }
 2836         /*
 2837          * Normal file deletion.
 2838          */
 2839         if ((dirrem->dm_state & RMDIR) == 0) {
 2840                 ip->i_nlink--;
 2841                 ip->i_flag |= IN_CHANGE;
 2842                 if (ip->i_nlink < ip->i_effnlink) {
 2843                         FREE_LOCK(&lk);
 2844                         panic("handle_workitem_remove: bad file delta");
 2845                 }
 2846                 inodedep->id_nlinkdelta = ip->i_nlink - ip->i_effnlink;
 2847                 FREE_LOCK(&lk);
 2848                 vput(vp);
 2849                 num_dirrem -= 1;
 2850                 WORKITEM_FREE(dirrem, D_DIRREM);
 2851                 return;
 2852         }
 2853         /*
 2854          * Directory deletion. Decrement reference count for both the
 2855          * just deleted parent directory entry and the reference for ".".
 2856          * Next truncate the directory to length zero. When the
 2857          * truncation completes, arrange to have the reference count on
 2858          * the parent decremented to account for the loss of "..".
 2859          */
 2860         ip->i_nlink -= 2;
 2861         ip->i_flag |= IN_CHANGE;
 2862         if (ip->i_nlink < ip->i_effnlink) {
 2863                 FREE_LOCK(&lk);
 2864                 panic("handle_workitem_remove: bad dir delta");
 2865         }
 2866         inodedep->id_nlinkdelta = ip->i_nlink - ip->i_effnlink;
 2867         FREE_LOCK(&lk);
 2868         if ((error = UFS_TRUNCATE(vp, (off_t)0, 0, p->p_ucred, p)) != 0)
 2869                 softdep_error("handle_workitem_remove: truncate", error);
 2870         /*
 2871          * Rename a directory to a new parent. Since, we are both deleting
 2872          * and creating a new directory entry, the link count on the new
 2873          * directory should not change. Thus we skip the followup dirrem.
 2874          */
 2875         if (dirrem->dm_state & DIRCHG) {
 2876                 vput(vp);
 2877                 num_dirrem -= 1;
 2878                 WORKITEM_FREE(dirrem, D_DIRREM);
 2879                 return;
 2880         }
 2881         /*
 2882          * If the inodedep does not exist, then the zero'ed inode has
 2883          * been written to disk. If the allocated inode has never been
 2884          * written to disk, then the on-disk inode is zero'ed. In either
 2885          * case we can remove the file immediately.
 2886          */
 2887         ACQUIRE_LOCK(&lk);
 2888         dirrem->dm_state = 0;
 2889         oldinum = dirrem->dm_oldinum;
 2890         dirrem->dm_oldinum = dirrem->dm_dirinum;
 2891         if (inodedep_lookup(ip->i_fs, oldinum, 0, &inodedep) == 0 ||
 2892             check_inode_unwritten(inodedep)) {
 2893                 FREE_LOCK(&lk);
 2894                 vput(vp);
 2895                 handle_workitem_remove(dirrem);
 2896                 return;
 2897         }
 2898         WORKLIST_INSERT(&inodedep->id_inowait, &dirrem->dm_list);
 2899         FREE_LOCK(&lk);
 2900         vput(vp);
 2901 }
 2902 
 2903 /*
 2904  * Inode de-allocation dependencies.
 2905  * 
 2906  * When an inode's link count is reduced to zero, it can be de-allocated. We
 2907  * found it convenient to postpone de-allocation until after the inode is
 2908  * written to disk with its new link count (zero).  At this point, all of the
 2909  * on-disk inode's block pointers are nullified and, with careful dependency
 2910  * list ordering, all dependencies related to the inode will be satisfied and
 2911  * the corresponding dependency structures de-allocated.  So, if/when the
 2912  * inode is reused, there will be no mixing of old dependencies with new
 2913  * ones.  This artificial dependency is set up by the block de-allocation
 2914  * procedure above (softdep_setup_freeblocks) and completed by the
 2915  * following procedure.
 2916  */
 2917 static void 
 2918 handle_workitem_freefile(freefile)
 2919         struct freefile *freefile;
 2920 {
 2921         struct vnode vp;
 2922         struct inode tip;
 2923         struct inodedep *idp;
 2924         int error;
 2925 
 2926 #ifdef DEBUG
 2927         ACQUIRE_LOCK(&lk);
 2928         error = inodedep_lookup(freefile->fx_fs, freefile->fx_oldinum, 0, &idp);
 2929         FREE_LOCK(&lk);
 2930         if (error)
 2931                 panic("handle_workitem_freefile: inodedep survived");
 2932 #endif
 2933         tip.i_devvp = freefile->fx_devvp;
 2934         tip.i_dev = freefile->fx_devvp->v_rdev;
 2935         tip.i_fs = freefile->fx_fs;
 2936         vp.v_data = &tip;
 2937         if ((error = ffs_freefile(&vp, freefile->fx_oldinum, freefile->fx_mode)) != 0)
 2938                 softdep_error("handle_workitem_freefile", error);
 2939         WORKITEM_FREE(freefile, D_FREEFILE);
 2940 }
 2941 
 2942 
 2943 /*
 2944  * Helper function which unlinks marker element from work list and returns
 2945  * the next element on the list.
 2946  */
 2947 static __inline struct worklist *
 2948 markernext(struct worklist *marker)
 2949 {
 2950         struct worklist *next;
 2951         
 2952         next = LIST_NEXT(marker, wk_list);
 2953         LIST_REMOVE(marker, wk_list);
 2954         return next;
 2955 }
 2956 
 2957 /*
 2958  * Disk writes.
 2959  * 
 2960  * The dependency structures constructed above are most actively used when file
 2961  * system blocks are written to disk.  No constraints are placed on when a
 2962  * block can be written, but unsatisfied update dependencies are made safe by
 2963  * modifying (or replacing) the source memory for the duration of the disk
 2964  * write.  When the disk write completes, the memory block is again brought
 2965  * up-to-date.
 2966  *
 2967  * In-core inode structure reclamation.
 2968  * 
 2969  * Because there are a finite number of "in-core" inode structures, they are
 2970  * reused regularly.  By transferring all inode-related dependencies to the
 2971  * in-memory inode block and indexing them separately (via "inodedep"s), we
 2972  * can allow "in-core" inode structures to be reused at any time and avoid
 2973  * any increase in contention.
 2974  *
 2975  * Called just before entering the device driver to initiate a new disk I/O.
 2976  * The buffer must be locked, thus, no I/O completion operations can occur
 2977  * while we are manipulating its associated dependencies.
 2978  */
 2979 static void 
 2980 softdep_disk_io_initiation(bp)
 2981         struct buf *bp;         /* structure describing disk write to occur */
 2982 {
 2983         struct worklist *wk;
 2984         struct worklist marker;
 2985         struct indirdep *indirdep;
 2986 
 2987         /*
 2988          * We only care about write operations. There should never
 2989          * be dependencies for reads.
 2990          */
 2991         if (bp->b_flags & B_READ)
 2992                 panic("softdep_disk_io_initiation: read");
 2993 
 2994         marker.wk_type = D_LAST + 1;    /* Not a normal workitem */
 2995         PHOLD(curproc);                 /* Don't swap out kernel stack */
 2996 
 2997         /*
 2998          * Do any necessary pre-I/O processing.
 2999          */
 3000         for (wk = LIST_FIRST(&bp->b_dep); wk != NULL;
 3001              wk = markernext(&marker)) {
 3002                 LIST_INSERT_AFTER(wk, &marker, wk_list);
 3003                 switch (wk->wk_type) {
 3004 
 3005                 case D_PAGEDEP:
 3006                         initiate_write_filepage(WK_PAGEDEP(wk), bp);
 3007                         continue;
 3008 
 3009                 case D_INODEDEP:
 3010                         initiate_write_inodeblock(WK_INODEDEP(wk), bp);
 3011                         continue;
 3012 
 3013                 case D_INDIRDEP:
 3014                         indirdep = WK_INDIRDEP(wk);
 3015                         if (indirdep->ir_state & GOINGAWAY)
 3016                                 panic("disk_io_initiation: indirdep gone");
 3017                         /*
 3018                          * If there are no remaining dependencies, this
 3019                          * will be writing the real pointers, so the
 3020                          * dependency can be freed.
 3021                          */
 3022                         if (LIST_FIRST(&indirdep->ir_deplisthd) == NULL) {
 3023                                 indirdep->ir_savebp->b_flags |= B_INVAL | B_NOCACHE;
 3024                                 brelse(indirdep->ir_savebp);
 3025                                 /* inline expand WORKLIST_REMOVE(wk); */
 3026                                 wk->wk_state &= ~ONWORKLIST;
 3027                                 LIST_REMOVE(wk, wk_list);
 3028                                 WORKITEM_FREE(indirdep, D_INDIRDEP);
 3029                                 continue;
 3030                         }
 3031                         /*
 3032                          * Replace up-to-date version with safe version.
 3033                          */
 3034                         MALLOC(indirdep->ir_saveddata, caddr_t, bp->b_bcount,
 3035                             M_INDIRDEP, M_SOFTDEP_FLAGS);
 3036                         ACQUIRE_LOCK(&lk);
 3037                         indirdep->ir_state &= ~ATTACHED;
 3038                         indirdep->ir_state |= UNDONE;
 3039                         bcopy(bp->b_data, indirdep->ir_saveddata, bp->b_bcount);
 3040                         bcopy(indirdep->ir_savebp->b_data, bp->b_data,
 3041                             bp->b_bcount);
 3042                         FREE_LOCK(&lk);
 3043                         continue;
 3044 
 3045                 case D_MKDIR:
 3046                 case D_BMSAFEMAP:
 3047                 case D_ALLOCDIRECT:
 3048                 case D_ALLOCINDIR:
 3049                         continue;
 3050 
 3051                 default:
 3052                         panic("handle_disk_io_initiation: Unexpected type %s",
 3053                             TYPENAME(wk->wk_type));
 3054                         /* NOTREACHED */
 3055                 }
 3056         }
 3057         PRELE(curproc);                 /* Allow swapout of kernel stack */
 3058 }
 3059 
 3060 /*
 3061  * Called from within the procedure above to deal with unsatisfied
 3062  * allocation dependencies in a directory. The buffer must be locked,
 3063  * thus, no I/O completion operations can occur while we are
 3064  * manipulating its associated dependencies.
 3065  */
 3066 static void
 3067 initiate_write_filepage(pagedep, bp)
 3068         struct pagedep *pagedep;
 3069         struct buf *bp;
 3070 {
 3071         struct diradd *dap;
 3072         struct direct *ep;
 3073         int i;
 3074 
 3075         if (pagedep->pd_state & IOSTARTED) {
 3076                 /*
 3077                  * This can only happen if there is a driver that does not
 3078                  * understand chaining. Here biodone will reissue the call
 3079                  * to strategy for the incomplete buffers.
 3080                  */
 3081                 printf("initiate_write_filepage: already started\n");
 3082                 return;
 3083         }
 3084         pagedep->pd_state |= IOSTARTED;
 3085         ACQUIRE_LOCK(&lk);
 3086         for (i = 0; i < DAHASHSZ; i++) {
 3087                 LIST_FOREACH(dap, &pagedep->pd_diraddhd[i], da_pdlist) {
 3088                         ep = (struct direct *)
 3089                             ((char *)bp->b_data + dap->da_offset);
 3090                         if (ep->d_ino != dap->da_newinum) {
 3091                                 FREE_LOCK(&lk);
 3092                                 panic("%s: dir inum %d != new %d",
 3093                                     "initiate_write_filepage",
 3094                                     ep->d_ino, dap->da_newinum);
 3095                         }
 3096                         if (dap->da_state & DIRCHG)
 3097                                 ep->d_ino = dap->da_previous->dm_oldinum;
 3098                         else
 3099                                 ep->d_ino = 0;
 3100                         dap->da_state &= ~ATTACHED;
 3101                         dap->da_state |= UNDONE;
 3102                 }
 3103         }
 3104         FREE_LOCK(&lk);
 3105 }
 3106 
 3107 /*
 3108  * Called from within the procedure above to deal with unsatisfied
 3109  * allocation dependencies in an inodeblock. The buffer must be
 3110  * locked, thus, no I/O completion operations can occur while we
 3111  * are manipulating its associated dependencies.
 3112  */
 3113 static void 
 3114 initiate_write_inodeblock(inodedep, bp)
 3115         struct inodedep *inodedep;
 3116         struct buf *bp;                 /* The inode block */
 3117 {
 3118         struct allocdirect *adp, *lastadp;
 3119         struct dinode *dp;
 3120         struct fs *fs;
 3121         ufs_lbn_t prevlbn = 0;
 3122         int i, deplist;
 3123 
 3124         if (inodedep->id_state & IOSTARTED)
 3125                 panic("initiate_write_inodeblock: already started");
 3126         inodedep->id_state |= IOSTARTED;
 3127         fs = inodedep->id_fs;
 3128         dp = (struct dinode *)bp->b_data +
 3129             ino_to_fsbo(fs, inodedep->id_ino);
 3130         /*
 3131          * If the bitmap is not yet written, then the allocated
 3132          * inode cannot be written to disk.
 3133          */
 3134         if ((inodedep->id_state & DEPCOMPLETE) == 0) {
 3135                 if (inodedep->id_savedino != NULL)
 3136                         panic("initiate_write_inodeblock: already doing I/O");
 3137                 MALLOC(inodedep->id_savedino, struct dinode *,
 3138                     sizeof(struct dinode), M_INODEDEP, M_SOFTDEP_FLAGS);
 3139                 *inodedep->id_savedino = *dp;
 3140                 bzero((caddr_t)dp, sizeof(struct dinode));
 3141                 dp->di_gen = inodedep->id_savedino->di_gen;
 3142                 return;
 3143         }
 3144         /*
 3145          * If no dependencies, then there is nothing to roll back.
 3146          */
 3147         inodedep->id_savedsize = dp->di_size;
 3148         if (TAILQ_FIRST(&inodedep->id_inoupdt) == NULL)
 3149                 return;
 3150         /*
 3151          * Set the dependencies to busy.
 3152          */
 3153         ACQUIRE_LOCK(&lk);
 3154         for (deplist = 0, adp = TAILQ_FIRST(&inodedep->id_inoupdt); adp;
 3155              adp = TAILQ_NEXT(adp, ad_next)) {
 3156 #ifdef DIAGNOSTIC
 3157                 if (deplist != 0 && prevlbn >= adp->ad_lbn) {
 3158                         FREE_LOCK(&lk);
 3159                         panic("softdep_write_inodeblock: lbn order");
 3160                 }
 3161                 prevlbn = adp->ad_lbn;
 3162                 if (adp->ad_lbn < NDADDR &&
 3163                     dp->di_db[adp->ad_lbn] != adp->ad_newblkno) {
 3164                         FREE_LOCK(&lk);
 3165                         panic("%s: direct pointer #%ld mismatch %d != %d",
 3166                             "softdep_write_inodeblock", adp->ad_lbn,
 3167                             dp->di_db[adp->ad_lbn], adp->ad_newblkno);
 3168                 }
 3169                 if (adp->ad_lbn >= NDADDR &&
 3170                     dp->di_ib[adp->ad_lbn - NDADDR] != adp->ad_newblkno) {
 3171                         FREE_LOCK(&lk);
 3172                         panic("%s: indirect pointer #%ld mismatch %d != %d",
 3173                             "softdep_write_inodeblock", adp->ad_lbn - NDADDR,
 3174                             dp->di_ib[adp->ad_lbn - NDADDR], adp->ad_newblkno);
 3175                 }
 3176                 deplist |= 1 << adp->ad_lbn;
 3177                 if ((adp->ad_state & ATTACHED) == 0) {
 3178                         FREE_LOCK(&lk);
 3179                         panic("softdep_write_inodeblock: Unknown state 0x%x",
 3180                             adp->ad_state);
 3181                 }
 3182 #endif /* DIAGNOSTIC */
 3183                 adp->ad_state &= ~ATTACHED;
 3184                 adp->ad_state |= UNDONE;
 3185         }
 3186         /*
 3187          * The on-disk inode cannot claim to be any larger than the last
 3188          * fragment that has been written. Otherwise, the on-disk inode
 3189          * might have fragments that were not the last block in the file
 3190          * which would corrupt the filesystem.
 3191          */
 3192         for (lastadp = NULL, adp = TAILQ_FIRST(&inodedep->id_inoupdt); adp;
 3193              lastadp = adp, adp = TAILQ_NEXT(adp, ad_next)) {
 3194                 if (adp->ad_lbn >= NDADDR)
 3195                         break;
 3196                 dp->di_db[adp->ad_lbn] = adp->ad_oldblkno;
 3197                 /* keep going until hitting a rollback to a frag */
 3198                 if (adp->ad_oldsize == 0 || adp->ad_oldsize == fs->fs_bsize)
 3199                         continue;
 3200                 dp->di_size = fs->fs_bsize * adp->ad_lbn + adp->ad_oldsize;
 3201                 for (i = adp->ad_lbn + 1; i < NDADDR; i++) {
 3202 #ifdef DIAGNOSTIC
 3203                         if (dp->di_db[i] != 0 && (deplist & (1 << i)) == 0) {
 3204                                 FREE_LOCK(&lk);
 3205                                 panic("softdep_write_inodeblock: lost dep1");
 3206                         }
 3207 #endif /* DIAGNOSTIC */
 3208                         dp->di_db[i] = 0;
 3209                 }
 3210                 for (i = 0; i < NIADDR; i++) {
 3211 #ifdef DIAGNOSTIC
 3212                         if (dp->di_ib[i] != 0 &&
 3213                             (deplist & ((1 << NDADDR) << i)) == 0) {
 3214                                 FREE_LOCK(&lk);
 3215                                 panic("softdep_write_inodeblock: lost dep2");
 3216                         }
 3217 #endif /* DIAGNOSTIC */
 3218                         dp->di_ib[i] = 0;
 3219                 }
 3220                 FREE_LOCK(&lk);
 3221                 return;
 3222         }
 3223         /*
 3224          * If we have zero'ed out the last allocated block of the file,
 3225          * roll back the size to the last currently allocated block.
 3226          * We know that this last allocated block is a full-sized as
 3227          * we already checked for fragments in the loop above.
 3228          */
 3229         if (lastadp != NULL &&
 3230             dp->di_size <= (lastadp->ad_lbn + 1) * fs->fs_bsize) {
 3231                 for (i = lastadp->ad_lbn; i >= 0; i--)
 3232                         if (dp->di_db[i] != 0)
 3233                                 break;
 3234                 dp->di_size = (i + 1) * fs->fs_bsize;
 3235         }
 3236         /*
 3237          * The only dependencies are for indirect blocks.
 3238          *
 3239          * The file size for indirect block additions is not guaranteed.
 3240          * Such a guarantee would be non-trivial to achieve. The conventional
 3241          * synchronous write implementation also does not make this guarantee.
 3242          * Fsck should catch and fix discrepancies. Arguably, the file size
 3243          * can be over-estimated without destroying integrity when the file
 3244          * moves into the indirect blocks (i.e., is large). If we want to
 3245          * postpone fsck, we are stuck with this argument.
 3246          */
 3247         for (; adp; adp = TAILQ_NEXT(adp, ad_next))
 3248                 dp->di_ib[adp->ad_lbn - NDADDR] = 0;
 3249         FREE_LOCK(&lk);
 3250 }
 3251 
 3252 /*
 3253  * This routine is called during the completion interrupt
 3254  * service routine for a disk write (from the procedure called
 3255  * by the device driver to inform the file system caches of
 3256  * a request completion).  It should be called early in this
 3257  * procedure, before the block is made available to other
 3258  * processes or other routines are called.
 3259  */
 3260 static void 
 3261 softdep_disk_write_complete(bp)
 3262         struct buf *bp;         /* describes the completed disk write */
 3263 {
 3264         struct worklist *wk;
 3265         struct workhead reattach;
 3266         struct newblk *newblk;
 3267         struct allocindir *aip;
 3268         struct allocdirect *adp;
 3269         struct indirdep *indirdep;
 3270         struct inodedep *inodedep;
 3271         struct bmsafemap *bmsafemap;
 3272 
 3273 #ifdef DEBUG
 3274         if (lk.lkt_held != -1)
 3275                 panic("softdep_disk_write_complete: lock is held");
 3276         lk.lkt_held = -2;
 3277 #endif
 3278         LIST_INIT(&reattach);
 3279         while ((wk = LIST_FIRST(&bp->b_dep)) != NULL) {
 3280                 WORKLIST_REMOVE(wk);
 3281                 switch (wk->wk_type) {
 3282 
 3283                 case D_PAGEDEP:
 3284                         if (handle_written_filepage(WK_PAGEDEP(wk), bp))
 3285                                 WORKLIST_INSERT(&reattach, wk);
 3286                         continue;
 3287 
 3288                 case D_INODEDEP:
 3289                         if (handle_written_inodeblock(WK_INODEDEP(wk), bp))
 3290                                 WORKLIST_INSERT(&reattach, wk);
 3291                         continue;
 3292 
 3293                 case D_BMSAFEMAP:
 3294                         bmsafemap = WK_BMSAFEMAP(wk);
 3295                         while ((newblk = LIST_FIRST(&bmsafemap->sm_newblkhd))) {
 3296                                 newblk->nb_state |= DEPCOMPLETE;
 3297                                 newblk->nb_bmsafemap = NULL;
 3298                                 LIST_REMOVE(newblk, nb_deps);
 3299                         }
 3300                         while ((adp =
 3301                            LIST_FIRST(&bmsafemap->sm_allocdirecthd))) {
 3302                                 adp->ad_state |= DEPCOMPLETE;
 3303                                 adp->ad_buf = NULL;
 3304                                 LIST_REMOVE(adp, ad_deps);
 3305                                 handle_allocdirect_partdone(adp);
 3306                         }
 3307                         while ((aip =
 3308                             LIST_FIRST(&bmsafemap->sm_allocindirhd))) {
 3309                                 aip->ai_state |= DEPCOMPLETE;
 3310                                 aip->ai_buf = NULL;
 3311                                 LIST_REMOVE(aip, ai_deps);
 3312                                 handle_allocindir_partdone(aip);
 3313                         }
 3314                         while ((inodedep =
 3315                              LIST_FIRST(&bmsafemap->sm_inodedephd)) != NULL) {
 3316                                 inodedep->id_state |= DEPCOMPLETE;
 3317                                 LIST_REMOVE(inodedep, id_deps);
 3318                                 inodedep->id_buf = NULL;
 3319                         }
 3320                         WORKITEM_FREE(bmsafemap, D_BMSAFEMAP);
 3321                         continue;
 3322 
 3323                 case D_MKDIR:
 3324                         handle_written_mkdir(WK_MKDIR(wk), MKDIR_BODY);
 3325                         continue;
 3326 
 3327                 case D_ALLOCDIRECT:
 3328                         adp = WK_ALLOCDIRECT(wk);
 3329                         adp->ad_state |= COMPLETE;
 3330                         handle_allocdirect_partdone(adp);
 3331                         continue;
 3332 
 3333                 case D_ALLOCINDIR:
 3334                         aip = WK_ALLOCINDIR(wk);
 3335                         aip->ai_state |= COMPLETE;
 3336                         handle_allocindir_partdone(aip);
 3337                         continue;
 3338 
 3339                 case D_INDIRDEP:
 3340                         indirdep = WK_INDIRDEP(wk);
 3341                         if (indirdep->ir_state & GOINGAWAY) {
 3342                                 lk.lkt_held = -1;
 3343                                 panic("disk_write_complete: indirdep gone");
 3344                         }
 3345                         bcopy(indirdep->ir_saveddata, bp->b_data, bp->b_bcount);
 3346                         FREE(indirdep->ir_saveddata, M_INDIRDEP);
 3347                         indirdep->ir_saveddata = 0;
 3348                         indirdep->ir_state &= ~UNDONE;
 3349                         indirdep->ir_state |= ATTACHED;
 3350                         while ((aip = LIST_FIRST(&indirdep->ir_donehd)) != 0) {
 3351                                 handle_allocindir_partdone(aip);
 3352                                 if (aip == LIST_FIRST(&indirdep->ir_donehd)) {
 3353                                         lk.lkt_held = -1;
 3354                                         panic("disk_write_complete: not gone");
 3355                                 }
 3356                         }
 3357                         WORKLIST_INSERT(&reattach, wk);
 3358                         if ((bp->b_flags & B_DELWRI) == 0)
 3359                                 stat_indir_blk_ptrs++;
 3360                         bdirty(bp);
 3361                         continue;
 3362 
 3363                 default:
 3364                         lk.lkt_held = -1;
 3365                         panic("handle_disk_write_complete: Unknown type %s",
 3366                             TYPENAME(wk->wk_type));
 3367                         /* NOTREACHED */
 3368                 }
 3369         }
 3370         /*
 3371          * Reattach any requests that must be redone.
 3372          */
 3373         while ((wk = LIST_FIRST(&reattach)) != NULL) {
 3374                 WORKLIST_REMOVE(wk);
 3375                 WORKLIST_INSERT(&bp->b_dep, wk);
 3376         }
 3377 #ifdef DEBUG
 3378         if (lk.lkt_held != -2)
 3379                 panic("softdep_disk_write_complete: lock lost");
 3380         lk.lkt_held = -1;
 3381 #endif
 3382 }
 3383 
 3384 /*
 3385  * Called from within softdep_disk_write_complete above. Note that
 3386  * this routine is always called from interrupt level with further
 3387  * splbio interrupts blocked.
 3388  */
 3389 static void 
 3390 handle_allocdirect_partdone(adp)
 3391         struct allocdirect *adp;        /* the completed allocdirect */
 3392 {
 3393         struct allocdirect *listadp;
 3394         struct inodedep *inodedep;
 3395         long bsize;
 3396 
 3397         if ((adp->ad_state & ALLCOMPLETE) != ALLCOMPLETE)
 3398                 return;
 3399         if (adp->ad_buf != NULL) {
 3400                 lk.lkt_held = -1;
 3401                 panic("handle_allocdirect_partdone: dangling dep");
 3402         }
 3403         /*
 3404          * The on-disk inode cannot claim to be any larger than the last
 3405          * fragment that has been written. Otherwise, the on-disk inode
 3406          * might have fragments that were not the last block in the file
 3407          * which would corrupt the filesystem. Thus, we cannot free any
 3408          * allocdirects after one whose ad_oldblkno claims a fragment as
 3409          * these blocks must be rolled back to zero before writing the inode.
 3410          * We check the currently active set of allocdirects in id_inoupdt.
 3411          */
 3412         inodedep = adp->ad_inodedep;
 3413         bsize = inodedep->id_fs->fs_bsize;
 3414         TAILQ_FOREACH(listadp, &inodedep->id_inoupdt, ad_next) {
 3415                 /* found our block */
 3416                 if (listadp == adp)
 3417                         break;
 3418                 /* continue if ad_oldlbn is not a fragment */
 3419                 if (listadp->ad_oldsize == 0 ||
 3420                     listadp->ad_oldsize == bsize)
 3421                         continue;
 3422                 /* hit a fragment */
 3423                 return;
 3424         }
 3425         /*
 3426          * If we have reached the end of the current list without
 3427          * finding the just finished dependency, then it must be
 3428          * on the future dependency list. Future dependencies cannot
 3429          * be freed until they are moved to the current list.
 3430          */
 3431         if (listadp == NULL) {
 3432 #ifdef DEBUG
 3433                 TAILQ_FOREACH(listadp, &inodedep->id_newinoupdt, ad_next)
 3434                         /* found our block */
 3435                         if (listadp == adp)
 3436                                 break;
 3437                 if (listadp == NULL) {
 3438                         lk.lkt_held = -1;
 3439                         panic("handle_allocdirect_partdone: lost dep");
 3440                 }
 3441 #endif /* DEBUG */
 3442                 return;
 3443         }
 3444         /*
 3445          * If we have found the just finished dependency, then free
 3446          * it along with anything that follows it that is complete.
 3447          */
 3448         for (; adp; adp = listadp) {
 3449                 listadp = TAILQ_NEXT(adp, ad_next);
 3450                 if ((adp->ad_state & ALLCOMPLETE) != ALLCOMPLETE)
 3451                         return;
 3452                 free_allocdirect(&inodedep->id_inoupdt, adp, 1);
 3453         }
 3454 }
 3455 
 3456 /*
 3457  * Called from within softdep_disk_write_complete above. Note that
 3458  * this routine is always called from interrupt level with further
 3459  * splbio interrupts blocked.
 3460  */
 3461 static void
 3462 handle_allocindir_partdone(aip)
 3463         struct allocindir *aip;         /* the completed allocindir */
 3464 {
 3465         struct indirdep *indirdep;
 3466 
 3467         if ((aip->ai_state & ALLCOMPLETE) != ALLCOMPLETE)
 3468                 return;
 3469         if (aip->ai_buf != NULL) {
 3470                 lk.lkt_held = -1;
 3471                 panic("handle_allocindir_partdone: dangling dependency");
 3472         }
 3473         indirdep = aip->ai_indirdep;
 3474         if (indirdep->ir_state & UNDONE) {
 3475                 LIST_REMOVE(aip, ai_next);
 3476                 LIST_INSERT_HEAD(&indirdep->ir_donehd, aip, ai_next);
 3477                 return;
 3478         }
 3479         ((ufs_daddr_t *)indirdep->ir_savebp->b_data)[aip->ai_offset] =
 3480             aip->ai_newblkno;
 3481         LIST_REMOVE(aip, ai_next);
 3482         if (aip->ai_freefrag != NULL)
 3483                 add_to_worklist(&aip->ai_freefrag->ff_list);
 3484         WORKITEM_FREE(aip, D_ALLOCINDIR);
 3485 }
 3486 
 3487 /*
 3488  * Called from within softdep_disk_write_complete above to restore
 3489  * in-memory inode block contents to their most up-to-date state. Note
 3490  * that this routine is always called from interrupt level with further
 3491  * splbio interrupts blocked.
 3492  */
 3493 static int 
 3494 handle_written_inodeblock(inodedep, bp)
 3495         struct inodedep *inodedep;
 3496         struct buf *bp;         /* buffer containing the inode block */
 3497 {
 3498         struct worklist *wk, *filefree;
 3499         struct allocdirect *adp, *nextadp;
 3500         struct dinode *dp;
 3501         int hadchanges;
 3502 
 3503         if ((inodedep->id_state & IOSTARTED) == 0) {
 3504                 lk.lkt_held = -1;
 3505                 panic("handle_written_inodeblock: not started");
 3506         }
 3507         inodedep->id_state &= ~IOSTARTED;
 3508         dp = (struct dinode *)bp->b_data +
 3509             ino_to_fsbo(inodedep->id_fs, inodedep->id_ino);
 3510         /*
 3511          * If we had to rollback the inode allocation because of
 3512          * bitmaps being incomplete, then simply restore it.
 3513          * Keep the block dirty so that it will not be reclaimed until
 3514          * all associated dependencies have been cleared and the
 3515          * corresponding updates written to disk.
 3516          */
 3517         if (inodedep->id_savedino != NULL) {
 3518                 *dp = *inodedep->id_savedino;
 3519                 FREE(inodedep->id_savedino, M_INODEDEP);
 3520                 inodedep->id_savedino = NULL;
 3521                 if ((bp->b_flags & B_DELWRI) == 0)
 3522                         stat_inode_bitmap++;
 3523                 bdirty(bp);
 3524                 return (1);
 3525         }
 3526         inodedep->id_state |= COMPLETE;
 3527         /*
 3528          * Roll forward anything that had to be rolled back before 
 3529          * the inode could be updated.
 3530          */
 3531         hadchanges = 0;
 3532         for (adp = TAILQ_FIRST(&inodedep->id_inoupdt); adp; adp = nextadp) {
 3533                 nextadp = TAILQ_NEXT(adp, ad_next);
 3534                 if (adp->ad_state & ATTACHED) {
 3535                         lk.lkt_held = -1;
 3536                         panic("handle_written_inodeblock: new entry");
 3537                 }
 3538                 if (adp->ad_lbn < NDADDR) {
 3539                         if (dp->di_db[adp->ad_lbn] != adp->ad_oldblkno) {
 3540                                 lk.lkt_held = -1;
 3541                                 panic("%s: %s #%ld mismatch %d != %d",
 3542                                     "handle_written_inodeblock",
 3543                                     "direct pointer", adp->ad_lbn,
 3544                                     dp->di_db[adp->ad_lbn], adp->ad_oldblkno);
 3545                         }
 3546                         dp->di_db[adp->ad_lbn] = adp->ad_newblkno;
 3547                 } else {
 3548                         if (dp->di_ib[adp->ad_lbn - NDADDR] != 0) {
 3549                                 lk.lkt_held = -1;
 3550                                 panic("%s: %s #%ld allocated as %d",
 3551                                     "handle_written_inodeblock",
 3552                                     "indirect pointer", adp->ad_lbn - NDADDR,
 3553                                     dp->di_ib[adp->ad_lbn - NDADDR]);
 3554                         }
 3555                         dp->di_ib[adp->ad_lbn - NDADDR] = adp->ad_newblkno;
 3556                 }
 3557                 adp->ad_state &= ~UNDONE;
 3558                 adp->ad_state |= ATTACHED;
 3559                 hadchanges = 1;
 3560         }
 3561         if (hadchanges && (bp->b_flags & B_DELWRI) == 0)
 3562                 stat_direct_blk_ptrs++;
 3563         /*
 3564          * Reset the file size to its most up-to-date value.
 3565          */
 3566         if (inodedep->id_savedsize == -1) {
 3567                 lk.lkt_held = -1;
 3568                 panic("handle_written_inodeblock: bad size");
 3569         }
 3570         if (dp->di_size != inodedep->id_savedsize) {
 3571                 dp->di_size = inodedep->id_savedsize;
 3572                 hadchanges = 1;
 3573         }
 3574         inodedep->id_savedsize = -1;
 3575         /*
 3576          * If there were any rollbacks in the inode block, then it must be
 3577          * marked dirty so that its will eventually get written back in
 3578          * its correct form.
 3579          */
 3580         if (hadchanges)
 3581                 bdirty(bp);
 3582         /*
 3583          * Process any allocdirects that completed during the update.
 3584          */
 3585         if ((adp = TAILQ_FIRST(&inodedep->id_inoupdt)) != NULL)
 3586                 handle_allocdirect_partdone(adp);
 3587         /*
 3588          * Process deallocations that were held pending until the
 3589          * inode had been written to disk. Freeing of the inode
 3590          * is delayed until after all blocks have been freed to
 3591          * avoid creation of new <vfsid, inum, lbn> triples
 3592          * before the old ones have been deleted.
 3593          */
 3594         filefree = NULL;
 3595         while ((wk = LIST_FIRST(&inodedep->id_bufwait)) != NULL) {
 3596                 WORKLIST_REMOVE(wk);
 3597                 switch (wk->wk_type) {
 3598 
 3599                 case D_FREEFILE:
 3600                         /*
 3601                          * We defer adding filefree to the worklist until
 3602                          * all other additions have been made to ensure
 3603                          * that it will be done after all the old blocks
 3604                          * have been freed.
 3605                          */
 3606                         if (filefree != NULL) {
 3607                                 lk.lkt_held = -1;
 3608                                 panic("handle_written_inodeblock: filefree");
 3609                         }
 3610                         filefree = wk;
 3611                         continue;
 3612 
 3613                 case D_MKDIR:
 3614                         handle_written_mkdir(WK_MKDIR(wk), MKDIR_PARENT);
 3615                         continue;
 3616 
 3617                 case D_DIRADD:
 3618                         diradd_inode_written(WK_DIRADD(wk), inodedep);
 3619                         continue;
 3620 
 3621                 case D_FREEBLKS:
 3622                         wk->wk_state |= COMPLETE;
 3623                         if ((wk->wk_state  & ALLCOMPLETE) != ALLCOMPLETE)
 3624                                 continue;
 3625                         /* -- fall through -- */
 3626                 case D_FREEFRAG:
 3627                 case D_DIRREM:
 3628                         add_to_worklist(wk);
 3629                         continue;
 3630 
 3631                 default:
 3632                         lk.lkt_held = -1;
 3633                         panic("handle_written_inodeblock: Unknown type %s",
 3634                             TYPENAME(wk->wk_type));
 3635                         /* NOTREACHED */
 3636                 }
 3637         }
 3638         if (filefree != NULL) {
 3639                 if (free_inodedep(inodedep) == 0) {
 3640                         lk.lkt_held = -1;
 3641                         panic("handle_written_inodeblock: live inodedep");
 3642                 }
 3643                 add_to_worklist(filefree);
 3644                 return (0);
 3645         }
 3646 
 3647         /*
 3648          * If no outstanding dependencies, free it.
 3649          */
 3650         if (free_inodedep(inodedep) || TAILQ_FIRST(&inodedep->id_inoupdt) == 0)
 3651                 return (0);
 3652         return (hadchanges);
 3653 }
 3654 
 3655 /*
 3656  * Process a diradd entry after its dependent inode has been written.
 3657  * This routine must be called with splbio interrupts blocked.
 3658  */
 3659 static void
 3660 diradd_inode_written(dap, inodedep)
 3661         struct diradd *dap;
 3662         struct inodedep *inodedep;
 3663 {
 3664         struct pagedep *pagedep;
 3665 
 3666         dap->da_state |= COMPLETE;
 3667         if ((dap->da_state & ALLCOMPLETE) == ALLCOMPLETE) {
 3668                 if (dap->da_state & DIRCHG)
 3669                         pagedep = dap->da_previous->dm_pagedep;
 3670                 else
 3671                         pagedep = dap->da_pagedep;
 3672                 LIST_REMOVE(dap, da_pdlist);
 3673                 LIST_INSERT_HEAD(&pagedep->pd_pendinghd, dap, da_pdlist);
 3674         }
 3675         WORKLIST_INSERT(&inodedep->id_pendinghd, &dap->da_list);
 3676 }
 3677 
 3678 /*
 3679  * Handle the completion of a mkdir dependency.
 3680  */
 3681 static void
 3682 handle_written_mkdir(mkdir, type)
 3683         struct mkdir *mkdir;
 3684         int type;
 3685 {
 3686         struct diradd *dap;
 3687         struct pagedep *pagedep;
 3688 
 3689         if (mkdir->md_state != type) {
 3690                 lk.lkt_held = -1;
 3691                 panic("handle_written_mkdir: bad type");
 3692         }
 3693         dap = mkdir->md_diradd;
 3694         dap->da_state &= ~type;
 3695         if ((dap->da_state & (MKDIR_PARENT | MKDIR_BODY)) == 0)
 3696                 dap->da_state |= DEPCOMPLETE;
 3697         if ((dap->da_state & ALLCOMPLETE) == ALLCOMPLETE) {
 3698                 if (dap->da_state & DIRCHG)
 3699                         pagedep = dap->da_previous->dm_pagedep;
 3700                 else
 3701                         pagedep = dap->da_pagedep;
 3702                 LIST_REMOVE(dap, da_pdlist);
 3703                 LIST_INSERT_HEAD(&pagedep->pd_pendinghd, dap, da_pdlist);
 3704         }
 3705         LIST_REMOVE(mkdir, md_mkdirs);
 3706         WORKITEM_FREE(mkdir, D_MKDIR);
 3707 }
 3708 
 3709 /*
 3710  * Called from within softdep_disk_write_complete above.
 3711  * A write operation was just completed. Removed inodes can
 3712  * now be freed and associated block pointers may be committed.
 3713  * Note that this routine is always called from interrupt level
 3714  * with further splbio interrupts blocked.
 3715  */
 3716 static int 
 3717 handle_written_filepage(pagedep, bp)
 3718         struct pagedep *pagedep;
 3719         struct buf *bp;         /* buffer containing the written page */
 3720 {
 3721         struct dirrem *dirrem;
 3722         struct diradd *dap, *nextdap;
 3723         struct direct *ep;
 3724         int i, chgs;
 3725 
 3726         if ((pagedep->pd_state & IOSTARTED) == 0) {
 3727                 lk.lkt_held = -1;
 3728                 panic("handle_written_filepage: not started");
 3729         }
 3730         pagedep->pd_state &= ~IOSTARTED;
 3731         /*
 3732          * Process any directory removals that have been committed.
 3733          */
 3734         while ((dirrem = LIST_FIRST(&pagedep->pd_dirremhd)) != NULL) {
 3735                 LIST_REMOVE(dirrem, dm_next);
 3736                 dirrem->dm_dirinum = pagedep->pd_ino;
 3737                 add_to_worklist(&dirrem->dm_list);
 3738         }
 3739         /*
 3740          * Free any directory additions that have been committed.
 3741          */
 3742         while ((dap = LIST_FIRST(&pagedep->pd_pendinghd)) != NULL)
 3743                 free_diradd(dap);
 3744         /*
 3745          * Uncommitted directory entries must be restored.
 3746          */
 3747         for (chgs = 0, i = 0; i < DAHASHSZ; i++) {
 3748                 for (dap = LIST_FIRST(&pagedep->pd_diraddhd[i]); dap;
 3749                      dap = nextdap) {
 3750                         nextdap = LIST_NEXT(dap, da_pdlist);
 3751                         if (dap->da_state & ATTACHED) {
 3752                                 lk.lkt_held = -1;
 3753                                 panic("handle_written_filepage: attached");
 3754                         }
 3755                         ep = (struct direct *)
 3756                             ((char *)bp->b_data + dap->da_offset);
 3757                         ep->d_ino = dap->da_newinum;
 3758                         dap->da_state &= ~UNDONE;
 3759                         dap->da_state |= ATTACHED;
 3760                         chgs = 1;
 3761                         /*
 3762                          * If the inode referenced by the directory has
 3763                          * been written out, then the dependency can be
 3764                          * moved to the pending list.
 3765                          */
 3766                         if ((dap->da_state & ALLCOMPLETE) == ALLCOMPLETE) {
 3767                                 LIST_REMOVE(dap, da_pdlist);
 3768                                 LIST_INSERT_HEAD(&pagedep->pd_pendinghd, dap,
 3769                                     da_pdlist);
 3770                         }
 3771                 }
 3772         }
 3773         /*
 3774          * If there were any rollbacks in the directory, then it must be
 3775          * marked dirty so that its will eventually get written back in
 3776          * its correct form.
 3777          */
 3778         if (chgs) {
 3779                 if ((bp->b_flags & B_DELWRI) == 0)
 3780                         stat_dir_entry++;
 3781                 bdirty(bp);
 3782         }
 3783         /*
 3784          * If no dependencies remain, the pagedep will be freed.
 3785          * Otherwise it will remain to update the page before it
 3786          * is written back to disk.
 3787          */
 3788         if (LIST_FIRST(&pagedep->pd_pendinghd) == 0) {
 3789                 for (i = 0; i < DAHASHSZ; i++)
 3790                         if (LIST_FIRST(&pagedep->pd_diraddhd[i]) != NULL)
 3791                                 break;
 3792                 if (i == DAHASHSZ) {
 3793                         LIST_REMOVE(pagedep, pd_hash);
 3794                         WORKITEM_FREE(pagedep, D_PAGEDEP);
 3795                         return (0);
 3796                 }
 3797         }
 3798         return (1);
 3799 }
 3800 
 3801 /*
 3802  * Writing back in-core inode structures.
 3803  * 
 3804  * The file system only accesses an inode's contents when it occupies an
 3805  * "in-core" inode structure.  These "in-core" structures are separate from
 3806  * the page frames used to cache inode blocks.  Only the latter are
 3807  * transferred to/from the disk.  So, when the updated contents of the
 3808  * "in-core" inode structure are copied to the corresponding in-memory inode
 3809  * block, the dependencies are also transferred.  The following procedure is
 3810  * called when copying a dirty "in-core" inode to a cached inode block.
 3811  */
 3812 
 3813 /*
 3814  * Called when an inode is loaded from disk. If the effective link count
 3815  * differed from the actual link count when it was last flushed, then we
 3816  * need to ensure that the correct effective link count is put back.
 3817  */
 3818 void 
 3819 softdep_load_inodeblock(ip)
 3820         struct inode *ip;       /* the "in_core" copy of the inode */
 3821 {
 3822         struct inodedep *inodedep;
 3823 
 3824         /*
 3825          * Check for alternate nlink count.
 3826          */
 3827         ip->i_effnlink = ip->i_nlink;
 3828         ACQUIRE_LOCK(&lk);
 3829         if (inodedep_lookup(ip->i_fs, ip->i_number, 0, &inodedep) == 0) {
 3830                 FREE_LOCK(&lk);
 3831                 return;
 3832         }
 3833         ip->i_effnlink -= inodedep->id_nlinkdelta;
 3834         FREE_LOCK(&lk);
 3835 }
 3836 
 3837 /*
 3838  * This routine is called just before the "in-core" inode
 3839  * information is to be copied to the in-memory inode block.
 3840  * Recall that an inode block contains several inodes. If
 3841  * the force flag is set, then the dependencies will be
 3842  * cleared so that the update can always be made. Note that
 3843  * the buffer is locked when this routine is called, so we
 3844  * will never be in the middle of writing the inode block 
 3845  * to disk.
 3846  */
 3847 void 
 3848 softdep_update_inodeblock(ip, bp, waitfor)
 3849         struct inode *ip;       /* the "in_core" copy of the inode */
 3850         struct buf *bp;         /* the buffer containing the inode block */
 3851         int waitfor;            /* nonzero => update must be allowed */
 3852 {
 3853         struct inodedep *inodedep;
 3854         struct worklist *wk;
 3855         int error, gotit;
 3856 
 3857         /*
 3858          * If the effective link count is not equal to the actual link
 3859          * count, then we must track the difference in an inodedep while
 3860          * the inode is (potentially) tossed out of the cache. Otherwise,
 3861          * if there is no existing inodedep, then there are no dependencies
 3862          * to track.
 3863          */
 3864         ACQUIRE_LOCK(&lk);
 3865         if (inodedep_lookup(ip->i_fs, ip->i_number, 0, &inodedep) == 0) {
 3866                 FREE_LOCK(&lk);
 3867                 if (ip->i_effnlink != ip->i_nlink)
 3868                         panic("softdep_update_inodeblock: bad link count");
 3869                 return;
 3870         }
 3871         if (inodedep->id_nlinkdelta != ip->i_nlink - ip->i_effnlink) {
 3872                 FREE_LOCK(&lk);
 3873                 panic("softdep_update_inodeblock: bad delta");
 3874         }
 3875         /*
 3876          * Changes have been initiated. Anything depending on these
 3877          * changes cannot occur until this inode has been written.
 3878          */
 3879         inodedep->id_state &= ~COMPLETE;
 3880         if ((inodedep->id_state & ONWORKLIST) == 0)
 3881                 WORKLIST_INSERT(&bp->b_dep, &inodedep->id_list);
 3882         /*
 3883          * Any new dependencies associated with the incore inode must 
 3884          * now be moved to the list associated with the buffer holding
 3885          * the in-memory copy of the inode. Once merged process any
 3886          * allocdirects that are completed by the merger.
 3887          */
 3888         merge_inode_lists(inodedep);
 3889         if (TAILQ_FIRST(&inodedep->id_inoupdt) != NULL)
 3890                 handle_allocdirect_partdone(TAILQ_FIRST(&inodedep->id_inoupdt));
 3891         /*
 3892          * Now that the inode has been pushed into the buffer, the
 3893          * operations dependent on the inode being written to disk
 3894          * can be moved to the id_bufwait so that they will be
 3895          * processed when the buffer I/O completes.
 3896          */
 3897         while ((wk = LIST_FIRST(&inodedep->id_inowait)) != NULL) {
 3898                 WORKLIST_REMOVE(wk);
 3899                 WORKLIST_INSERT(&inodedep->id_bufwait, wk);
 3900         }
 3901         /*
 3902          * Newly allocated inodes cannot be written until the bitmap
 3903          * that allocates them have been written (indicated by
 3904          * DEPCOMPLETE being set in id_state). If we are doing a
 3905          * forced sync (e.g., an fsync on a file), we force the bitmap
 3906          * to be written so that the update can be done.
 3907          */
 3908         if ((inodedep->id_state & DEPCOMPLETE) != 0 || waitfor == 0) {
 3909                 FREE_LOCK(&lk);
 3910                 return;
 3911         }
 3912         gotit = getdirtybuf(&inodedep->id_buf, MNT_WAIT);
 3913         FREE_LOCK(&lk);
 3914         if (gotit &&
 3915             (error = VOP_BWRITE(inodedep->id_buf->b_vp, inodedep->id_buf)) != 0)
 3916                 softdep_error("softdep_update_inodeblock: bwrite", error);
 3917         if ((inodedep->id_state & DEPCOMPLETE) == 0)
 3918                 panic("softdep_update_inodeblock: update failed");
 3919 }
 3920 
 3921 /*
 3922  * Merge the new inode dependency list (id_newinoupdt) into the old
 3923  * inode dependency list (id_inoupdt). This routine must be called
 3924  * with splbio interrupts blocked.
 3925  */
 3926 static void
 3927 merge_inode_lists(inodedep)
 3928         struct inodedep *inodedep;
 3929 {
 3930         struct allocdirect *listadp, *newadp;
 3931 
 3932         newadp = TAILQ_FIRST(&inodedep->id_newinoupdt);
 3933         for (listadp = TAILQ_FIRST(&inodedep->id_inoupdt); listadp && newadp;) {
 3934                 if (listadp->ad_lbn < newadp->ad_lbn) {
 3935                         listadp = TAILQ_NEXT(listadp, ad_next);
 3936                         continue;
 3937                 }
 3938                 TAILQ_REMOVE(&inodedep->id_newinoupdt, newadp, ad_next);
 3939                 TAILQ_INSERT_BEFORE(listadp, newadp, ad_next);
 3940                 if (listadp->ad_lbn == newadp->ad_lbn) {
 3941                         allocdirect_merge(&inodedep->id_inoupdt, newadp,
 3942                             listadp);
 3943                         listadp = newadp;
 3944                 }
 3945                 newadp = TAILQ_FIRST(&inodedep->id_newinoupdt);
 3946         }
 3947         while ((newadp = TAILQ_FIRST(&inodedep->id_newinoupdt)) != NULL) {
 3948                 TAILQ_REMOVE(&inodedep->id_newinoupdt, newadp, ad_next);
 3949                 TAILQ_INSERT_TAIL(&inodedep->id_inoupdt, newadp, ad_next);
 3950         }
 3951 }
 3952 
 3953 /*
 3954  * If we are doing an fsync, then we must ensure that any directory
 3955  * entries for the inode have been written after the inode gets to disk.
 3956  */
 3957 static int
 3958 softdep_fsync(vp)
 3959         struct vnode *vp;       /* the "in_core" copy of the inode */
 3960 {
 3961         struct inodedep *inodedep;
 3962         struct pagedep *pagedep;
 3963         struct worklist *wk;
 3964         struct diradd *dap;
 3965         struct mount *mnt;
 3966         struct vnode *pvp;
 3967         struct inode *ip;
 3968         struct buf *bp;
 3969         struct fs *fs;
 3970         struct proc *p = CURPROC;               /* XXX */
 3971         int error, flushparent;
 3972         ino_t parentino;
 3973         ufs_lbn_t lbn;
 3974 
 3975         ip = VTOI(vp);
 3976         fs = ip->i_fs;
 3977         ACQUIRE_LOCK(&lk);
 3978         if (inodedep_lookup(fs, ip->i_number, 0, &inodedep) == 0) {
 3979                 FREE_LOCK(&lk);
 3980                 return (0);
 3981         }
 3982         if (LIST_FIRST(&inodedep->id_inowait) != NULL ||
 3983             LIST_FIRST(&inodedep->id_bufwait) != NULL ||
 3984             TAILQ_FIRST(&inodedep->id_inoupdt) != NULL ||
 3985             TAILQ_FIRST(&inodedep->id_newinoupdt) != NULL) {
 3986                 FREE_LOCK(&lk);
 3987                 panic("softdep_fsync: pending ops");
 3988         }
 3989         for (error = 0, flushparent = 0; ; ) {
 3990                 if ((wk = LIST_FIRST(&inodedep->id_pendinghd)) == NULL)
 3991                         break;
 3992                 if (wk->wk_type != D_DIRADD) {
 3993                         FREE_LOCK(&lk);
 3994                         panic("softdep_fsync: Unexpected type %s",
 3995                             TYPENAME(wk->wk_type));
 3996                 }
 3997                 dap = WK_DIRADD(wk);
 3998                 /*
 3999                  * Flush our parent if this directory entry
 4000                  * has a MKDIR_PARENT dependency.
 4001                  */
 4002                 if (dap->da_state & DIRCHG)
 4003                         pagedep = dap->da_previous->dm_pagedep;
 4004                 else
 4005                         pagedep = dap->da_pagedep;
 4006                 mnt = pagedep->pd_mnt;
 4007                 parentino = pagedep->pd_ino;
 4008                 lbn = pagedep->pd_lbn;
 4009                 if ((dap->da_state & (MKDIR_BODY | COMPLETE)) != COMPLETE) {
 4010                         FREE_LOCK(&lk);
 4011                         panic("softdep_fsync: dirty");
 4012                 }
 4013                 flushparent = dap->da_state & MKDIR_PARENT;
 4014                 /*
 4015                  * If we are being fsync'ed as part of vgone'ing this vnode,
 4016                  * then we will not be able to release and recover the
 4017                  * vnode below, so we just have to give up on writing its
 4018                  * directory entry out. It will eventually be written, just
 4019                  * not now, but then the user was not asking to have it
 4020                  * written, so we are not breaking any promises.
 4021                  */
 4022                 if (vp->v_flag & VXLOCK)
 4023                         break;
 4024                 /*
 4025                  * We prevent deadlock by always fetching inodes from the
 4026                  * root, moving down the directory tree. Thus, when fetching
 4027                  * our parent directory, we must unlock ourselves before
 4028                  * requesting the lock on our parent. See the comment in
 4029                  * ufs_lookup for details on possible races.
 4030                  */
 4031                 FREE_LOCK(&lk);
 4032                 VOP_UNLOCK(vp, 0, p);
 4033                 error = VFS_VGET(mnt, parentino, &pvp);
 4034                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 4035                 if (error != 0)
 4036                         return (error);
 4037                 if (flushparent) {
 4038                         if ((error = UFS_UPDATE(pvp, 1)) != 0) {
 4039                                 vput(pvp);
 4040                                 return (error);
 4041                         }
 4042                 }
 4043                 /*
 4044                  * Flush directory page containing the inode's name.
 4045                  */
 4046                 error = bread(pvp, lbn, blksize(fs, VTOI(pvp), lbn), p->p_ucred,
 4047                     &bp);
 4048                 if (error == 0)
 4049                         error = VOP_BWRITE(bp->b_vp, bp);
 4050                 vput(pvp);
 4051                 if (error != 0)
 4052                         return (error);
 4053                 ACQUIRE_LOCK(&lk);
 4054                 if (inodedep_lookup(fs, ip->i_number, 0, &inodedep) == 0)
 4055                         break;
 4056         }
 4057         FREE_LOCK(&lk);
 4058         return (0);
 4059 }
 4060 
 4061 /*
 4062  * Flush all the dirty bitmaps associated with the block device
 4063  * before flushing the rest of the dirty blocks so as to reduce
 4064  * the number of dependencies that will have to be rolled back.
 4065  */
 4066 void
 4067 softdep_fsync_mountdev(vp)
 4068         struct vnode *vp;
 4069 {
 4070         struct buf *bp, *nbp;
 4071         struct worklist *wk;
 4072 
 4073         if (!vn_isdisk(vp, NULL))
 4074                 panic("softdep_fsync_mountdev: vnode not a disk");
 4075         ACQUIRE_LOCK(&lk);
 4076         for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
 4077                 nbp = TAILQ_NEXT(bp, b_vnbufs);
 4078                 /* 
 4079                  * If it is already scheduled, skip to the next buffer.
 4080                  */
 4081                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
 4082                         continue;
 4083                 if ((bp->b_flags & B_DELWRI) == 0) {
 4084                         FREE_LOCK(&lk);
 4085                         panic("softdep_fsync_mountdev: not dirty");
 4086                 }
 4087                 /*
 4088                  * We are only interested in bitmaps with outstanding
 4089                  * dependencies.
 4090                  */
 4091                 if ((wk = LIST_FIRST(&bp->b_dep)) == NULL ||
 4092                     wk->wk_type != D_BMSAFEMAP ||
 4093                     (bp->b_xflags & BX_BKGRDINPROG)) {
 4094                         BUF_UNLOCK(bp);
 4095                         continue;
 4096                 }
 4097                 bremfree(bp);
 4098                 FREE_LOCK(&lk);
 4099                 (void) bawrite(bp);
 4100                 ACQUIRE_LOCK(&lk);
 4101                 /*
 4102                  * Since we may have slept during the I/O, we need 
 4103                  * to start from a known point.
 4104                  */
 4105                 nbp = TAILQ_FIRST(&vp->v_dirtyblkhd);
 4106         }
 4107         drain_output(vp, 1);
 4108         FREE_LOCK(&lk);
 4109 }
 4110 
 4111 /*
 4112  * This routine is called when we are trying to synchronously flush a
 4113  * file. This routine must eliminate any filesystem metadata dependencies
 4114  * so that the syncing routine can succeed by pushing the dirty blocks
 4115  * associated with the file. If any I/O errors occur, they are returned.
 4116  */
 4117 int
 4118 softdep_sync_metadata(ap)
 4119         struct vop_fsync_args /* {
 4120                 struct vnode *a_vp;
 4121                 struct ucred *a_cred;
 4122                 int a_waitfor;
 4123                 struct proc *a_p;
 4124         } */ *ap;
 4125 {
 4126         struct vnode *vp = ap->a_vp;
 4127         struct pagedep *pagedep;
 4128         struct allocdirect *adp;
 4129         struct allocindir *aip;
 4130         struct buf *bp, *nbp;
 4131         struct worklist *wk;
 4132         int i, error, waitfor;
 4133 
 4134         /*
 4135          * Check whether this vnode is involved in a filesystem
 4136          * that is doing soft dependency processing.
 4137          */
 4138         if (!vn_isdisk(vp, NULL)) {
 4139                 if (!DOINGSOFTDEP(vp))
 4140                         return (0);
 4141         } else
 4142                 if (vp->v_specmountpoint == NULL ||
 4143                     (vp->v_specmountpoint->mnt_flag & MNT_SOFTDEP) == 0)
 4144                         return (0);
 4145         /*
 4146          * Ensure that any direct block dependencies have been cleared.
 4147          */
 4148         ACQUIRE_LOCK(&lk);
 4149         if ((error = flush_inodedep_deps(VTOI(vp)->i_fs, VTOI(vp)->i_number))) {
 4150                 FREE_LOCK(&lk);
 4151                 return (error);
 4152         }
 4153         /*
 4154          * For most files, the only metadata dependencies are the
 4155          * cylinder group maps that allocate their inode or blocks.
 4156          * The block allocation dependencies can be found by traversing
 4157          * the dependency lists for any buffers that remain on their
 4158          * dirty buffer list. The inode allocation dependency will
 4159          * be resolved when the inode is updated with MNT_WAIT.
 4160          * This work is done in two passes. The first pass grabs most
 4161          * of the buffers and begins asynchronously writing them. The
 4162          * only way to wait for these asynchronous writes is to sleep
 4163          * on the filesystem vnode which may stay busy for a long time
 4164          * if the filesystem is active. So, instead, we make a second
 4165          * pass over the dependencies blocking on each write. In the
 4166          * usual case we will be blocking against a write that we
 4167          * initiated, so when it is done the dependency will have been
 4168          * resolved. Thus the second pass is expected to end quickly.
 4169          */
 4170         waitfor = MNT_NOWAIT;
 4171 top:
 4172         /*
 4173          * We must wait for any I/O in progress to finish so that
 4174          * all potential buffers on the dirty list will be visible.
 4175          */
 4176         drain_output(vp, 1);
 4177         if (getdirtybuf(&TAILQ_FIRST(&vp->v_dirtyblkhd), MNT_WAIT) == 0) {
 4178                 FREE_LOCK(&lk);
 4179                 return (0);
 4180         }
 4181         bp = TAILQ_FIRST(&vp->v_dirtyblkhd);
 4182 loop:
 4183         /*
 4184          * As we hold the buffer locked, none of its dependencies
 4185          * will disappear.
 4186          */
 4187         LIST_FOREACH(wk, &bp->b_dep, wk_list) {
 4188                 switch (wk->wk_type) {
 4189 
 4190                 case D_ALLOCDIRECT:
 4191                         adp = WK_ALLOCDIRECT(wk);
 4192                         if (adp->ad_state & DEPCOMPLETE)
 4193                                 break;
 4194                         nbp = adp->ad_buf;
 4195                         if (getdirtybuf(&nbp, waitfor) == 0)
 4196                                 break;
 4197                         FREE_LOCK(&lk);
 4198                         if (waitfor == MNT_NOWAIT) {
 4199                                 bawrite(nbp);
 4200                         } else if ((error = VOP_BWRITE(nbp->b_vp, nbp)) != 0) {
 4201                                 bawrite(bp);
 4202                                 return (error);
 4203                         }
 4204                         ACQUIRE_LOCK(&lk);
 4205                         break;
 4206 
 4207                 case D_ALLOCINDIR:
 4208                         aip = WK_ALLOCINDIR(wk);
 4209                         if (aip->ai_state & DEPCOMPLETE)
 4210                                 break;
 4211                         nbp = aip->ai_buf;
 4212                         if (getdirtybuf(&nbp, waitfor) == 0)
 4213                                 break;
 4214                         FREE_LOCK(&lk);
 4215                         if (waitfor == MNT_NOWAIT) {
 4216                                 bawrite(nbp);
 4217                         } else if ((error = VOP_BWRITE(nbp->b_vp, nbp)) != 0) {
 4218                                 bawrite(bp);
 4219                                 return (error);
 4220                         }
 4221                         ACQUIRE_LOCK(&lk);
 4222                         break;
 4223 
 4224                 case D_INDIRDEP:
 4225                 restart:
 4226 
 4227                         LIST_FOREACH(aip, &WK_INDIRDEP(wk)->ir_deplisthd, ai_next) {
 4228                                 if (aip->ai_state & DEPCOMPLETE)
 4229                                         continue;
 4230                                 nbp = aip->ai_buf;
 4231                                 if (getdirtybuf(&nbp, MNT_WAIT) == 0)
 4232                                         goto restart;
 4233                                 FREE_LOCK(&lk);
 4234                                 if ((error = VOP_BWRITE(nbp->b_vp, nbp)) != 0) {
 4235                                         bawrite(bp);
 4236                                         return (error);
 4237                                 }
 4238                                 ACQUIRE_LOCK(&lk);
 4239                                 goto restart;
 4240                         }
 4241                         break;
 4242 
 4243                 case D_INODEDEP:
 4244                         if ((error = flush_inodedep_deps(WK_INODEDEP(wk)->id_fs,
 4245                             WK_INODEDEP(wk)->id_ino)) != 0) {
 4246                                 FREE_LOCK(&lk);
 4247                                 bawrite(bp);
 4248                                 return (error);
 4249                         }
 4250                         break;
 4251 
 4252                 case D_PAGEDEP:
 4253                         /*
 4254                          * We are trying to sync a directory that may
 4255                          * have dependencies on both its own metadata
 4256                          * and/or dependencies on the inodes of any
 4257                          * recently allocated files. We walk its diradd
 4258                          * lists pushing out the associated inode.
 4259                          */
 4260                         pagedep = WK_PAGEDEP(wk);
 4261                         for (i = 0; i < DAHASHSZ; i++) {
 4262                                 if (LIST_FIRST(&pagedep->pd_diraddhd[i]) == 0)
 4263                                         continue;
 4264                                 if ((error =
 4265                                     flush_pagedep_deps(vp, pagedep->pd_mnt,
 4266                                                 &pagedep->pd_diraddhd[i]))) {
 4267                                         FREE_LOCK(&lk);
 4268                                         bawrite(bp);
 4269                                         return (error);
 4270                                 }
 4271                         }
 4272                         break;
 4273 
 4274                 case D_MKDIR:
 4275                         /*
 4276                          * This case should never happen if the vnode has
 4277                          * been properly sync'ed. However, if this function
 4278                          * is used at a place where the vnode has not yet
 4279                          * been sync'ed, this dependency can show up. So,
 4280                          * rather than panic, just flush it.
 4281                          */
 4282                         nbp = WK_MKDIR(wk)->md_buf;
 4283                         if (getdirtybuf(&nbp, waitfor) == 0)
 4284                                 break;
 4285                         FREE_LOCK(&lk);
 4286                         if (waitfor == MNT_NOWAIT) {
 4287                                 bawrite(nbp);
 4288                         } else if ((error = VOP_BWRITE(nbp->b_vp, nbp)) != 0) {
 4289                                 bawrite(bp);
 4290                                 return (error);
 4291                         }
 4292                         ACQUIRE_LOCK(&lk);
 4293                         break;
 4294 
 4295                 case D_BMSAFEMAP:
 4296                         /*
 4297                          * This case should never happen if the vnode has
 4298                          * been properly sync'ed. However, if this function
 4299                          * is used at a place where the vnode has not yet
 4300                          * been sync'ed, this dependency can show up. So,
 4301                          * rather than panic, just flush it.
 4302                          */
 4303                         nbp = WK_BMSAFEMAP(wk)->sm_buf;
 4304                         if (getdirtybuf(&nbp, MNT_NOWAIT) == 0)
 4305                                 break;
 4306                         FREE_LOCK(&lk);
 4307                         if (waitfor == MNT_NOWAIT) {
 4308                                 bawrite(nbp);
 4309                         } else if ((error = VOP_BWRITE(nbp->b_vp, nbp)) != 0) {
 4310                                 bawrite(bp);
 4311                                 return (error);
 4312                         }
 4313                         ACQUIRE_LOCK(&lk);
 4314                         break;
 4315 
 4316                 default:
 4317                         FREE_LOCK(&lk);
 4318                         panic("softdep_sync_metadata: Unknown type %s",
 4319                             TYPENAME(wk->wk_type));
 4320                         /* NOTREACHED */
 4321                 }
 4322         }
 4323         (void) getdirtybuf(&TAILQ_NEXT(bp, b_vnbufs), MNT_WAIT);
 4324         nbp = TAILQ_NEXT(bp, b_vnbufs);
 4325         FREE_LOCK(&lk);
 4326         bawrite(bp);
 4327         ACQUIRE_LOCK(&lk);
 4328         if (nbp != NULL) {
 4329                 bp = nbp;
 4330                 goto loop;
 4331         }
 4332         /*
 4333          * The brief unlock is to allow any pent up dependency
 4334          * processing to be done.  Then proceed with the second pass.
 4335          */
 4336         if (waitfor == MNT_NOWAIT) {
 4337                 waitfor = MNT_WAIT;
 4338                 FREE_LOCK(&lk);
 4339                 ACQUIRE_LOCK(&lk);
 4340                 goto top;
 4341         }
 4342 
 4343         /*
 4344          * If we have managed to get rid of all the dirty buffers,
 4345          * then we are done. For certain directories and block
 4346          * devices, we may need to do further work.
 4347          *
 4348          * We must wait for any I/O in progress to finish so that
 4349          * all potential buffers on the dirty list will be visible.
 4350          */
 4351         drain_output(vp, 1);
 4352         if (TAILQ_FIRST(&vp->v_dirtyblkhd) == NULL) {
 4353                 FREE_LOCK(&lk);
 4354                 return (0);
 4355         }
 4356 
 4357         FREE_LOCK(&lk);
 4358         /*
 4359          * If we are trying to sync a block device, some of its buffers may
 4360          * contain metadata that cannot be written until the contents of some
 4361          * partially written files have been written to disk. The only easy
 4362          * way to accomplish this is to sync the entire filesystem (luckily
 4363          * this happens rarely).
 4364          */
 4365         if (vn_isdisk(vp, NULL) && 
 4366             vp->v_specmountpoint && !VOP_ISLOCKED(vp, NULL) &&
 4367             (error = VFS_SYNC(vp->v_specmountpoint, MNT_WAIT, ap->a_cred,
 4368              ap->a_p)) != 0)
 4369                 return (error);
 4370         return (0);
 4371 }
 4372 
 4373 /*
 4374  * Flush the dependencies associated with an inodedep.
 4375  * Called with splbio blocked.
 4376  */
 4377 static int
 4378 flush_inodedep_deps(fs, ino)
 4379         struct fs *fs;
 4380         ino_t ino;
 4381 {
 4382         struct inodedep *inodedep;
 4383         struct allocdirect *adp;
 4384         int error, waitfor;
 4385         struct buf *bp;
 4386 
 4387         /*
 4388          * This work is done in two passes. The first pass grabs most
 4389          * of the buffers and begins asynchronously writing them. The
 4390          * only way to wait for these asynchronous writes is to sleep
 4391          * on the filesystem vnode which may stay busy for a long time
 4392          * if the filesystem is active. So, instead, we make a second
 4393          * pass over the dependencies blocking on each write. In the
 4394          * usual case we will be blocking against a write that we
 4395          * initiated, so when it is done the dependency will have been
 4396          * resolved. Thus the second pass is expected to end quickly.
 4397          * We give a brief window at the top of the loop to allow
 4398          * any pending I/O to complete.
 4399          */
 4400         for (waitfor = MNT_NOWAIT; ; ) {
 4401                 FREE_LOCK(&lk);
 4402                 ACQUIRE_LOCK(&lk);
 4403                 if (inodedep_lookup(fs, ino, 0, &inodedep) == 0)
 4404                         return (0);
 4405                 TAILQ_FOREACH(adp, &inodedep->id_inoupdt, ad_next) {
 4406                         if (adp->ad_state & DEPCOMPLETE)
 4407                                 continue;
 4408                         bp = adp->ad_buf;
 4409                         if (getdirtybuf(&bp, waitfor) == 0) {
 4410                                 if (waitfor == MNT_NOWAIT)
 4411                                         continue;
 4412                                 break;
 4413                         }
 4414                         FREE_LOCK(&lk);
 4415                         if (waitfor == MNT_NOWAIT) {
 4416                                 bawrite(bp);
 4417                         } else if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0) {
 4418                                 ACQUIRE_LOCK(&lk);
 4419                                 return (error);
 4420                         }
 4421                         ACQUIRE_LOCK(&lk);
 4422                         break;
 4423                 }
 4424                 if (adp != NULL)
 4425                         continue;
 4426                 TAILQ_FOREACH(adp, &inodedep->id_newinoupdt, ad_next) {
 4427                         if (adp->ad_state & DEPCOMPLETE)
 4428                                 continue;
 4429                         bp = adp->ad_buf;
 4430                         if (getdirtybuf(&bp, waitfor) == 0) {
 4431                                 if (waitfor == MNT_NOWAIT)
 4432                                         continue;
 4433                                 break;
 4434                         }
 4435                         FREE_LOCK(&lk);
 4436                         if (waitfor == MNT_NOWAIT) {
 4437                                 bawrite(bp);
 4438                         } else if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0) {
 4439                                 ACQUIRE_LOCK(&lk);
 4440                                 return (error);
 4441                         }
 4442                         ACQUIRE_LOCK(&lk);
 4443                         break;
 4444                 }
 4445                 if (adp != NULL)
 4446                         continue;
 4447                 /*
 4448                  * If pass2, we are done, otherwise do pass 2.
 4449                  */
 4450                 if (waitfor == MNT_WAIT)
 4451                         break;
 4452                 waitfor = MNT_WAIT;
 4453         }
 4454         /*
 4455          * Try freeing inodedep in case all dependencies have been removed.
 4456          */
 4457         if (inodedep_lookup(fs, ino, 0, &inodedep) != 0)
 4458                 (void) free_inodedep(inodedep);
 4459         return (0);
 4460 }
 4461 
 4462 /*
 4463  * Eliminate a pagedep dependency by flushing out all its diradd dependencies.
 4464  * Called with splbio blocked.
 4465  */
 4466 static int
 4467 flush_pagedep_deps(pvp, mp, diraddhdp)
 4468         struct vnode *pvp;
 4469         struct mount *mp;
 4470         struct diraddhd *diraddhdp;
 4471 {
 4472         struct proc *p = CURPROC;       /* XXX */
 4473         struct inodedep *inodedep;
 4474         struct ufsmount *ump;
 4475         struct diradd *dap;
 4476         struct vnode *vp;
 4477         int gotit, error = 0;
 4478         struct buf *bp;
 4479         ino_t inum;
 4480 
 4481         ump = VFSTOUFS(mp);
 4482         while ((dap = LIST_FIRST(diraddhdp)) != NULL) {
 4483                 /*
 4484                  * Flush ourselves if this directory entry
 4485                  * has a MKDIR_PARENT dependency.
 4486                  */
 4487                 if (dap->da_state & MKDIR_PARENT) {
 4488                         FREE_LOCK(&lk);
 4489                         if ((error = UFS_UPDATE(pvp, 1)) != 0)
 4490                                 break;
 4491                         ACQUIRE_LOCK(&lk);
 4492                         /*
 4493                          * If that cleared dependencies, go on to next.
 4494                          */
 4495                         if (dap != LIST_FIRST(diraddhdp))
 4496                                 continue;
 4497                         if (dap->da_state & MKDIR_PARENT) {
 4498                                 FREE_LOCK(&lk);
 4499                                 panic("flush_pagedep_deps: MKDIR_PARENT");
 4500                         }
 4501                 }
 4502                 /*
 4503                  * A newly allocated directory must have its "." and
 4504                  * ".." entries written out before its name can be
 4505                  * committed in its parent. We do not want or need
 4506                  * the full semantics of a synchronous VOP_FSYNC as
 4507                  * that may end up here again, once for each directory
 4508                  * level in the filesystem. Instead, we push the blocks
 4509                  * and wait for them to clear. We have to fsync twice
 4510                  * because the first call may choose to defer blocks
 4511                  * that still have dependencies, but deferral will
 4512                  * happen at most once.
 4513                  */
 4514                 inum = dap->da_newinum;
 4515                 if (dap->da_state & MKDIR_BODY) {
 4516                         FREE_LOCK(&lk);
 4517                         if ((error = VFS_VGET(mp, inum, &vp)) != 0)
 4518                                 break;
 4519                         if ((error=VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p)) ||
 4520                             (error=VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p))) {
 4521                                 vput(vp);
 4522                                 break;
 4523                         }
 4524                         drain_output(vp, 0);
 4525                         vput(vp);
 4526                         ACQUIRE_LOCK(&lk);
 4527                         /*
 4528                          * If that cleared dependencies, go on to next.
 4529                          */
 4530                         if (dap != LIST_FIRST(diraddhdp))
 4531                                 continue;
 4532                         if (dap->da_state & MKDIR_BODY) {
 4533                                 FREE_LOCK(&lk);
 4534                                 panic("flush_pagedep_deps: MKDIR_BODY");
 4535                         }
 4536                 }
 4537                 /*
 4538                  * Flush the inode on which the directory entry depends.
 4539                  * Having accounted for MKDIR_PARENT and MKDIR_BODY above,
 4540                  * the only remaining dependency is that the updated inode
 4541                  * count must get pushed to disk. The inode has already
 4542                  * been pushed into its inode buffer (via VOP_UPDATE) at
 4543                  * the time of the reference count change. So we need only
 4544                  * locate that buffer, ensure that there will be no rollback
 4545                  * caused by a bitmap dependency, then write the inode buffer.
 4546                  */
 4547                 if (inodedep_lookup(ump->um_fs, inum, 0, &inodedep) == 0) {
 4548                         FREE_LOCK(&lk);
 4549                         panic("flush_pagedep_deps: lost inode");
 4550                 }
 4551                 /*
 4552                  * If the inode still has bitmap dependencies,
 4553                  * push them to disk.
 4554                  */
 4555                 if ((inodedep->id_state & DEPCOMPLETE) == 0) {
 4556                         gotit = getdirtybuf(&inodedep->id_buf, MNT_WAIT);
 4557                         FREE_LOCK(&lk);
 4558                         if (gotit &&
 4559                             (error = VOP_BWRITE(inodedep->id_buf->b_vp,
 4560                              inodedep->id_buf)) != 0)
 4561                                 break;
 4562                         ACQUIRE_LOCK(&lk);
 4563                         if (dap != LIST_FIRST(diraddhdp))
 4564                                 continue;
 4565                 }
 4566                 /*
 4567                  * If the inode is still sitting in a buffer waiting
 4568                  * to be written, push it to disk.
 4569                  */
 4570                 FREE_LOCK(&lk);
 4571                 if ((error = bread(ump->um_devvp,
 4572                     fsbtodb(ump->um_fs, ino_to_fsba(ump->um_fs, inum)),
 4573                     (int)ump->um_fs->fs_bsize, NOCRED, &bp)) != 0)
 4574                         break;
 4575                 if ((error = VOP_BWRITE(bp->b_vp, bp)) != 0)
 4576                         break;
 4577                 ACQUIRE_LOCK(&lk);
 4578                 /*
 4579                  * If we have failed to get rid of all the dependencies
 4580                  * then something is seriously wrong.
 4581                  */
 4582                 if (dap == LIST_FIRST(diraddhdp)) {
 4583                         FREE_LOCK(&lk);
 4584                         panic("flush_pagedep_deps: flush failed");
 4585                 }
 4586         }
 4587         if (error)
 4588                 ACQUIRE_LOCK(&lk);
 4589         return (error);
 4590 }
 4591 
 4592 /*
 4593  * A large burst of file addition or deletion activity can drive the
 4594  * memory load excessively high. First attempt to slow things down
 4595  * using the techniques below. If that fails, this routine requests
 4596  * the offending operations to fall back to running synchronously
 4597  * until the memory load returns to a reasonable level.
 4598  */
 4599 int
 4600 softdep_slowdown(vp)
 4601         struct vnode *vp;
 4602 {
 4603         int max_softdeps_hard;
 4604 
 4605         max_softdeps_hard = max_softdeps * 11 / 10;
 4606         if (num_dirrem < max_softdeps_hard / 2 &&
 4607             num_inodedep < max_softdeps_hard)
 4608                 return (0);
 4609         stat_sync_limit_hit += 1;
 4610         return (1);
 4611 }
 4612 
 4613 /*
 4614  * If memory utilization has gotten too high, deliberately slow things
 4615  * down and speed up the I/O processing.
 4616  */
 4617 static int
 4618 request_cleanup(resource, islocked)
 4619         int resource;
 4620         int islocked;
 4621 {
 4622         struct proc *p = CURPROC;
 4623 
 4624         /*
 4625          * We never hold up the filesystem syncer process.
 4626          */
 4627         if (p == filesys_syncer)
 4628                 return (0);
 4629         /*
 4630          * First check to see if the work list has gotten backlogged.
 4631          * If it has, co-opt this process to help clean up two entries.
 4632          * Because this process may hold inodes locked, we cannot
 4633          * handle any remove requests that might block on a locked
 4634          * inode as that could lead to deadlock.
 4635          */
 4636         if (num_on_worklist > max_softdeps / 10) {
 4637                 if (islocked)
 4638                         FREE_LOCK(&lk);
 4639                 process_worklist_item(NULL, LK_NOWAIT);
 4640                 process_worklist_item(NULL, LK_NOWAIT);
 4641                 stat_worklist_push += 2;
 4642                 if (islocked)
 4643                         ACQUIRE_LOCK(&lk);
 4644                 return(1);
 4645         }
 4646 
 4647         /*
 4648          * If we are resource constrained on inode dependencies, try
 4649          * flushing some dirty inodes. Otherwise, we are constrained
 4650          * by file deletions, so try accelerating flushes of directories
 4651          * with removal dependencies. We would like to do the cleanup
 4652          * here, but we probably hold an inode locked at this point and 
 4653          * that might deadlock against one that we try to clean. So,
 4654          * the best that we can do is request the syncer daemon to do
 4655          * the cleanup for us.
 4656          */
 4657         switch (resource) {
 4658 
 4659         case FLUSH_INODES:
 4660                 stat_ino_limit_push += 1;
 4661                 req_clear_inodedeps += 1;
 4662                 stat_countp = &stat_ino_limit_hit;
 4663                 break;
 4664 
 4665         case FLUSH_REMOVE:
 4666                 stat_blk_limit_push += 1;
 4667                 req_clear_remove += 1;
 4668                 stat_countp = &stat_blk_limit_hit;
 4669                 break;
 4670 
 4671         default:
 4672                 if (islocked)
 4673                         FREE_LOCK(&lk);
 4674                 panic("request_cleanup: unknown type");
 4675         }
 4676         /*
 4677          * Hopefully the syncer daemon will catch up and awaken us.
 4678          * We wait at most tickdelay before proceeding in any case.
 4679          */
 4680         if (islocked == 0)
 4681                 ACQUIRE_LOCK(&lk);
 4682         proc_waiting += 1;
 4683         if (handle.callout == NULL)
 4684                 handle = timeout(pause_timer, 0, tickdelay > 2 ? tickdelay : 2);
 4685         interlocked_sleep(&lk, SLEEP, (caddr_t)&proc_waiting, PPAUSE,
 4686             "softupdate", 0);
 4687         proc_waiting -= 1;
 4688         if (islocked == 0)
 4689                 FREE_LOCK(&lk);
 4690         return (1);
 4691 }
 4692 
 4693 /*
 4694  * Awaken processes pausing in request_cleanup and clear proc_waiting
 4695  * to indicate that there is no longer a timer running.
 4696  */
 4697 void
 4698 pause_timer(arg)
 4699         void *arg;
 4700 {
 4701 
 4702         *stat_countp += 1;
 4703         wakeup_one(&proc_waiting);
 4704         if (proc_waiting > 0)
 4705                 handle = timeout(pause_timer, 0, tickdelay > 2 ? tickdelay : 2);
 4706         else
 4707                 handle.callout = NULL;
 4708 }
 4709 
 4710 /*
 4711  * Flush out a directory with at least one removal dependency in an effort to
 4712  * reduce the number of dirrem, freefile, and freeblks dependency structures.
 4713  */
 4714 static void
 4715 clear_remove(p)
 4716         struct proc *p;
 4717 {
 4718         struct pagedep_hashhead *pagedephd;
 4719         struct pagedep *pagedep;
 4720         static int next = 0;
 4721         struct mount *mp;
 4722         struct vnode *vp;
 4723         int error, cnt;
 4724         ino_t ino;
 4725 
 4726         ACQUIRE_LOCK(&lk);
 4727         for (cnt = 0; cnt < pagedep_hash; cnt++) {
 4728                 pagedephd = &pagedep_hashtbl[next++];
 4729                 if (next >= pagedep_hash)
 4730                         next = 0;
 4731                 LIST_FOREACH(pagedep, pagedephd, pd_hash) {
 4732                         if (LIST_FIRST(&pagedep->pd_dirremhd) == NULL)
 4733                                 continue;
 4734                         mp = pagedep->pd_mnt;
 4735                         ino = pagedep->pd_ino;
 4736                         FREE_LOCK(&lk);
 4737                         if ((error = VFS_VGET(mp, ino, &vp)) != 0) {
 4738                                 softdep_error("clear_remove: vget", error);
 4739                                 return;
 4740                         }
 4741                         if ((error = VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p)))
 4742                                 softdep_error("clear_remove: fsync", error);
 4743                         drain_output(vp, 0);
 4744                         vput(vp);
 4745                         return;
 4746                 }
 4747         }
 4748         FREE_LOCK(&lk);
 4749 }
 4750 
 4751 /*
 4752  * Clear out a block of dirty inodes in an effort to reduce
 4753  * the number of inodedep dependency structures.
 4754  */
 4755 static void
 4756 clear_inodedeps(p)
 4757         struct proc *p;
 4758 {
 4759         struct inodedep_hashhead *inodedephd;
 4760         struct inodedep *inodedep;
 4761         static int next = 0;
 4762         struct mount *mp;
 4763         struct vnode *vp;
 4764         struct fs *fs;
 4765         int error, cnt;
 4766         ino_t firstino, lastino, ino;
 4767 
 4768         ACQUIRE_LOCK(&lk);
 4769         /*
 4770          * Pick a random inode dependency to be cleared.
 4771          * We will then gather up all the inodes in its block 
 4772          * that have dependencies and flush them out.
 4773          */
 4774         for (cnt = 0; cnt < inodedep_hash; cnt++) {
 4775                 inodedephd = &inodedep_hashtbl[next++];
 4776                 if (next >= inodedep_hash)
 4777                         next = 0;
 4778                 if ((inodedep = LIST_FIRST(inodedephd)) != NULL)
 4779                         break;
 4780         }
 4781         if (inodedep == NULL)
 4782                 return;
 4783         /*
 4784          * Ugly code to find mount point given pointer to superblock.
 4785          */
 4786         fs = inodedep->id_fs;
 4787         TAILQ_FOREACH(mp, &mountlist, mnt_list)
 4788                 if ((mp->mnt_flag & MNT_SOFTDEP) && fs == VFSTOUFS(mp)->um_fs)
 4789                         break;
 4790         /*
 4791          * Find the last inode in the block with dependencies.
 4792          */
 4793         firstino = inodedep->id_ino & ~(INOPB(fs) - 1);
 4794         for (lastino = firstino + INOPB(fs) - 1; lastino > firstino; lastino--)
 4795                 if (inodedep_lookup(fs, lastino, 0, &inodedep) != 0)
 4796                         break;
 4797         /*
 4798          * Asynchronously push all but the last inode with dependencies.
 4799          * Synchronously push the last inode with dependencies to ensure
 4800          * that the inode block gets written to free up the inodedeps.
 4801          */
 4802         for (ino = firstino; ino <= lastino; ino++) {
 4803                 if (inodedep_lookup(fs, ino, 0, &inodedep) == 0)
 4804                         continue;
 4805                 FREE_LOCK(&lk);
 4806                 if ((error = VFS_VGET(mp, ino, &vp)) != 0) {
 4807                         softdep_error("clear_inodedeps: vget", error);
 4808                         return;
 4809                 }
 4810                 if (ino == lastino) {
 4811                         if ((error = VOP_FSYNC(vp, p->p_ucred, MNT_WAIT, p)))
 4812                                 softdep_error("clear_inodedeps: fsync1", error);
 4813                 } else {
 4814                         if ((error = VOP_FSYNC(vp, p->p_ucred, MNT_NOWAIT, p)))
 4815                                 softdep_error("clear_inodedeps: fsync2", error);
 4816                         drain_output(vp, 0);
 4817                 }
 4818                 vput(vp);
 4819                 ACQUIRE_LOCK(&lk);
 4820         }
 4821         FREE_LOCK(&lk);
 4822 }
 4823 
 4824 /*
 4825  * Function to determine if the buffer has outstanding dependencies
 4826  * that will cause a roll-back if the buffer is written. If wantcount
 4827  * is set, return number of dependencies, otherwise just yes or no.
 4828  */
 4829 static int
 4830 softdep_count_dependencies(bp, wantcount)
 4831         struct buf *bp;
 4832         int wantcount;
 4833 {
 4834         struct worklist *wk;
 4835         struct inodedep *inodedep;
 4836         struct indirdep *indirdep;
 4837         struct allocindir *aip;
 4838         struct pagedep *pagedep;
 4839         struct diradd *dap;
 4840         int i, retval;
 4841 
 4842         retval = 0;
 4843         ACQUIRE_LOCK(&lk);
 4844         LIST_FOREACH(wk, &bp->b_dep, wk_list) {
 4845                 switch (wk->wk_type) {
 4846 
 4847                 case D_INODEDEP:
 4848                         inodedep = WK_INODEDEP(wk);
 4849                         if ((inodedep->id_state & DEPCOMPLETE) == 0) {
 4850                                 /* bitmap allocation dependency */
 4851                                 retval += 1;
 4852                                 if (!wantcount)
 4853                                         goto out;
 4854                         }
 4855                         if (TAILQ_FIRST(&inodedep->id_inoupdt)) {
 4856                                 /* direct block pointer dependency */
 4857                                 retval += 1;
 4858                                 if (!wantcount)
 4859                                         goto out;
 4860                         }
 4861                         continue;
 4862 
 4863                 case D_INDIRDEP:
 4864                         indirdep = WK_INDIRDEP(wk);
 4865 
 4866                         LIST_FOREACH(aip, &indirdep->ir_deplisthd, ai_next) {
 4867                                 /* indirect block pointer dependency */
 4868                                 retval += 1;
 4869                                 if (!wantcount)
 4870                                         goto out;
 4871                         }
 4872                         continue;
 4873 
 4874                 case D_PAGEDEP:
 4875                         pagedep = WK_PAGEDEP(wk);
 4876                         for (i = 0; i < DAHASHSZ; i++) {
 4877 
 4878                                 LIST_FOREACH(dap, &pagedep->pd_diraddhd[i], da_pdlist) {
 4879                                         /* directory entry dependency */
 4880                                         retval += 1;
 4881                                         if (!wantcount)
 4882                                                 goto out;
 4883                                 }
 4884                         }
 4885                         continue;
 4886 
 4887                 case D_BMSAFEMAP:
 4888                 case D_ALLOCDIRECT:
 4889                 case D_ALLOCINDIR:
 4890                 case D_MKDIR:
 4891                         /* never a dependency on these blocks */
 4892                         continue;
 4893 
 4894                 default:
 4895                         FREE_LOCK(&lk);
 4896                         panic("softdep_check_for_rollback: Unexpected type %s",
 4897                             TYPENAME(wk->wk_type));
 4898                         /* NOTREACHED */
 4899                 }
 4900         }
 4901 out:
 4902         FREE_LOCK(&lk);
 4903         return retval;
 4904 }
 4905 
 4906 /*
 4907  * Acquire exclusive access to a buffer.
 4908  * Must be called with splbio blocked.
 4909  * Return 1 if buffer was acquired.
 4910  */
 4911 static int
 4912 getdirtybuf(bpp, waitfor)
 4913         struct buf **bpp;
 4914         int waitfor;
 4915 {
 4916         struct buf *bp;
 4917         int error;
 4918 
 4919         for (;;) {
 4920                 if ((bp = *bpp) == NULL)
 4921                         return (0);
 4922                 if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT) == 0) {
 4923                         if ((bp->b_xflags & BX_BKGRDINPROG) == 0)
 4924                                 break;
 4925                         BUF_UNLOCK(bp);
 4926                         if (waitfor != MNT_WAIT)
 4927                                 return (0);
 4928                         bp->b_xflags |= BX_BKGRDWAIT;
 4929                         interlocked_sleep(&lk, SLEEP, &bp->b_xflags, PRIBIO,
 4930                             "getbuf", 0);
 4931                         continue;
 4932                 }
 4933                 if (waitfor != MNT_WAIT)
 4934                         return (0);
 4935                 error = interlocked_sleep(&lk, LOCKBUF, bp,
 4936                     LK_EXCLUSIVE | LK_SLEEPFAIL, 0, 0);
 4937                 if (error != ENOLCK) {
 4938                         FREE_LOCK(&lk);
 4939                         panic("getdirtybuf: inconsistent lock");
 4940                 }
 4941         }
 4942         if ((bp->b_flags & B_DELWRI) == 0) {
 4943                 BUF_UNLOCK(bp);
 4944                 return (0);
 4945         }
 4946         bremfree(bp);
 4947         return (1);
 4948 }
 4949 
 4950 /*
 4951  * Wait for pending output on a vnode to complete.
 4952  * Must be called with vnode locked.
 4953  */
 4954 static void
 4955 drain_output(vp, islocked)
 4956         struct vnode *vp;
 4957         int islocked;
 4958 {
 4959 
 4960         if (!islocked)
 4961                 ACQUIRE_LOCK(&lk);
 4962         while (vp->v_numoutput) {
 4963                 vp->v_flag |= VBWAIT;
 4964                 interlocked_sleep(&lk, SLEEP, (caddr_t)&vp->v_numoutput,
 4965                     PRIBIO + 1, "drainvp", 0);
 4966         }
 4967         if (!islocked)
 4968                 FREE_LOCK(&lk);
 4969 }
 4970 
 4971 /*
 4972  * Called whenever a buffer that is being invalidated or reallocated
 4973  * contains dependencies. This should only happen if an I/O error has
 4974  * occurred. The routine is called with the buffer locked.
 4975  */ 
 4976 static void
 4977 softdep_deallocate_dependencies(bp)
 4978         struct buf *bp;
 4979 {
 4980 
 4981         if ((bp->b_flags & B_ERROR) == 0)
 4982                 panic("softdep_deallocate_dependencies: dangling deps");
 4983         softdep_error(bp->b_vp->v_mount->mnt_stat.f_mntonname, bp->b_error);
 4984         panic("softdep_deallocate_dependencies: unrecovered I/O error");
 4985 }
 4986 
 4987 /*
 4988  * Function to handle asynchronous write errors in the filesystem.
 4989  */
 4990 void
 4991 softdep_error(func, error)
 4992         char *func;
 4993         int error;
 4994 {
 4995 
 4996         /* XXX should do something better! */
 4997         printf("%s: got error %d while accessing filesystem\n", func, error);
 4998 }

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